Microwave accelerate d preparation of [bmim][HSO4] ionic liquid
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第24卷 第6期 武汉纺织大学学报V ol.24 No.62011年12月 J O U R N A L O F W U H A N T E X T I L E U N I V E R S I T Y D e c. 2011________________________________ *通讯作者:杨锋(1963-),男,教授,研究方向:计算化学及理论研究.废弃PET 瓶的微波促乙二醇降解施 川,张露露,杨 锋*(武汉纺织大学 化学与化工学院,湖北 武汉 430073)摘 要:PET 做为一种常用的塑料制品,已经使用了很多年,在为人类生产生活提供便利的同时也产生了环境污染。
通过微波降解PET 具有效率高、时间短、产率高的特点,本文通过微波研究乙二醇的降解,并得出最佳反应条件。
关键词:微波;废弃PET;醇解中图分类号:TQ317.9 文献标识码:A 文章编号:1009-5160(2011)06-0051-04聚对苯二甲酸乙二醇酯(PET)是由对苯二甲酸和乙二醇酯聚合的产物。
由于其具有优良的性能,广泛的用于纺织、餐饮、电器等产业中[1]。
由于人们生活水平不断提高,对PET的需求也越来越大,PET的使用呈逐渐上升的趋势[2]。
截止2005年,全世界的PET中产量达到了4091kt。
我国PET 生产能力和产量也大幅度增长, 截止2005年已达到12530kt。
PET的应用范围也在逐渐扩展,越来越多的取代传统的玻璃、陶瓷、钢铁等材料。
废弃的PET虽说对人体无毒无害,但是其在自然界中降解周期太长,再加上大量的使用,对环境造成了巨大的破坏和资源浪费[3]。
废弃PET的回收和再利用受到重视,一般的都是采取较为简单的方法:融化后再吹瓶、填埋或者直接燃烧。
对废弃PET的处理化学方法有明显的优势。
而且比物理方法有经济上的优势。
常用的方法有:水解法、醇解法。
但是水解法要求温度和和压力比较高,而且一般催化剂都是强酸或者强碱,对环境会进一步污染。
英语中常见的前缀2007年01月02日星期二13:59一.反义前缀1)表示否定意义的前缀a- = not, without表示"无"、"不"a-+ symmetry (对称)→asymmetry不对称a- + typical (典型的)→atypical非典型的dis- = not, deprive of表示"不"、"剥夺"、"取消"dis- + agree(一致,同意)→disagree不一致,意见不合dis- + arm(武装)→disarm解除武装dis-+approve (同意,批准)→disapprove不赞成,不准il-, im-, in-, ir-= not表示"非"、"不"il- + literate(有读写能力的)→illiterate文盲的im- + possible(可能的)→impossible不可能的in- + valuable(有价值的)→invaluable无价的,非常珍贵的ir- + responsible(对……负责任的)→irresponsible不负责任的ir- + religious(宗教的,虔诚的)→irreligious无信仰的,不虔诚的ir- + regular(规则的)→irregular不规则的2)表示相反、对立意义的前缀anti-, counter-, with- = against, opposite to, back表示"反"、"对"、"往回" anti- +warlike(好战的)→antiwarlike非好战的counter-+ measure(措施)→countermeasure对策counter- + attack(攻击)→counterattack反击with- + draw(移动)→withdraw离开,撤退,取消3)表示错误意义的前缀mal- =badly表示"坏的"、"不良的"mal-+ function(功能,作用)→malfunction机能失常,发生故障mal- +treat(对待)→maltreat虐待mal-+ nutrition(营养)→malnutrition营养不良mis- = wrongly, badly表示"误"mis- + advise(劝告)→misadvise给予错误的劝告mis- + place(安放)→misplace误置,误放mis-+ understand(理解)→misunderstand误解二.表示位置方向的前缀1)a- = on, toward表示"在……之上"、"向着"a- + shore(岸)→ashore在岸上a- + side(旁边)→aside在旁边2)circum- = around表示"周围"、"环绕"circum- + lunar(月球的)→circumlunar绕月旋转的circum- +polar(极地的)→circumpolar极地附近的3)de- = down表示"向下"de- + scend(上涌)→descend下降de- + grade(级别)→degrade降级4)ex- = out表示"向外"ex- + press(压)→express表达ex- +port(港口)→export向外运送,出口5)fore- = before表示"先"、"前"fore- + arm(手臂)→forearm前臂fore- + ground(背景)→foreground前景6)inter- = between, among表示"之间"inter- + national(国家的)→international国际间的inter-+ action(行动)→interaction互动inter- + net(网)→internet互联网7)mid- = middle表示"中间的"mid- + night(夜)→midnight半夜mid- + summer(夏天)→midsummer仲夏mid-+ term(学期)→midterm期中8)post- = after表示"在……之后"post- + war(战争)→postwar战后的post- + script(手稿)→postscript附笔9)sub- = under表示"下"、"副"sub- + marine(海洋的)→submarine海底的,潜水艇sub- + way(道路)→subway地铁sub- + title(标题)→subtitle副标题三.表示数量的前缀mono-, uni- = single表示"单一"mono- + tone(音调)→monotone单调uni- +lateral(侧面的,旁边的)→unilateral单边的bi- = double, two表示"两"、"双"bi- + lingual(舌音的)→bilingual双语的bi- + monthly(每月一次的)→bimonthly双月的amphi- = two ways/two sides表示"二,两侧,两端" amphibia 两栖类,amphichroic 两性反应的tri- = three表示"三"tri- + angle(角,角度)→triangle三角形quadra-,quadri- = four表示"四"quadra-,quadri-quadrant 四分体,象限quadriceps 四头肌quadruple 四倍penta-,pento- = five表示"五"pentagon 五角形pentacyclic 五环的hex-,hexa- = six表示"六"hexagonal 六角形hept-,hepta- = seven表示"七"heptagon 七边形octa-,octo- = eight表示"八"octagon 八角形octopus 八爪鱼deci- = tenth表示"十分之一"deci- + mal(形容词词尾)→decimal十进制的deci- + meter(米)→decimeter分米hecto-, centi- = hundred, hundredth表示"百"、"百分之一"hecto- + metre(米)→hectometre <英>(长度单位)百米centi- + meter(米)→centimeter厘米kilo- = thousand表示"千"kilo- + gram(克)→kilogram千克kilo-+ watt(瓦)→kilowatt千瓦milli- = thousandth表示"千分之一"milli-+ gram(克)→milligram毫克milli- + meter(米)→millimeter毫米hemi-, semi- = half表示"半"hemi- + sphere(球体)→hemisphere半球semi- + circle(圆圈)→semicircle半圆形semi- + conductor(导体)→semiconductor半导体micro- = small表示"微小的"micro- + wave(波)→microwave微波micro-+ economics(经济学)→microeconomics微观经济学micro- + analysis(分析)→microanalysis微量分析macro- = large表示"大的"macro-+effect(效应)→macroeffect宏观效应macro- + economics(经济学)→macroeconomics宏观经济学macro-+ molecule(分子)→macromolecule高分子multi- = many, much表示"多的"multi- + color(颜色)→multicolor多种颜色的multi-+ channel(渠道)→multichannel多通话线路的multi- + purpose(目的)→multipurpose多目标的,用途广的英语中常见的后缀2007年01月02日星期二14:01一、名词性后缀1,-age为抽象名词后缀,表示行为,状态和全体总称percentage百分数,百分率,voltage电压,伏特数,lavage灌洗,洗,出法,gavage管词法,curettage刮除法,shortage不足,缺少。
通信英语各章词汇PCM 原理principle 原理be dependent on 依赖, 取决于sample采样/样值quantize量化, 分层code编码/码scheme方案, 设计, 安排describe 叙述, 描述description叙述, 描述ampl itude幅, 幅度binary 二进制的minimum最小值, 最小量theoretical理论上的repeti tion 重复, 反复reexamination再审查, 重考maximum最大值reduce减少, 缩小interchange互换, 转换, 相互影响method方式, 方法, 手段overcome克服, 打败, 征服environment环境, 周围情况lightning电光, 闪电, 雷电strike击, 敲, 打spark发火花, 打火, 闪ignition点火, 点火装置signal-to-noise ratio 信噪比satellite卫星terrestrial地球的, 地面的, 大地的by comparison 比较起来, 相对之下parameter参数, 系数at tenuation衰减, 衰耗inherent固有的, 内在的assume假设, 假定decoder解( 译) 码器codec编译码器interleave交插, 交错, 插接appropriate适当的, 合适的unique 惟一的, 独特的reoccur 再发生, 再次发生抽样量化与编码:sampling,quantizing and coding话路:speech channel幅值: amplitude value抽样频率: sampling frequency抽样速率: sampling rate脉冲流: stream of pulses重复率: repetition rate 编码过程: coding process模拟信号: analog signal传输质量: transmission quality数字通信: digital communication数字传输: digital transmission含噪声的环境: noisy environment传输路由: transmission path信噪比:signal-to-noise ratio信号电平:signal levels噪声功率: noise power地面系统: terrestrial system二进制传输: binary transmission反向操作: reverse operation8-位码序列: 8-digit sequence接受端: receiving terminal 帧格式:frame format同步字:synchronization word实现这三项功能的方案:the schemes for performing these three functions一串幅值: a series of amplitude values电话质量的话路 a speech channel of telephone quality一个8位二进制码的序列: a sequence of 8-binary digits理论上的最小抽样频率:a minimum theoretical sampling frequency占据着300Hz到3.4kHz频率范围的话路: a voice channel occupying the range 300 to 每个样值8-位码: 8-digits per sample value汽车点火系统的打火: the sparking of a car ignition system重复率为64kHz的脉冲流: the stream of the pulses with a repetition rate of 64kHz 真实信号与噪声信号的关系: relationship of the true signal to the noise signal由卫星上接受到的信号:the signal received from a satellite一条特定消息中的全部信息:the complete informatian about a particular message被传信号的波形:the shape of the transmitted signal由传输路由引入的衰减: the attenuation introduced by transmission path将抽样的幅值转换成一串脉冲的单元:the unit that converts sampled amplitude value t o a set of pulses涉及到第一路,第二路及其他各路的序列: a sequence relating to channel 1,2 and so on 被称为同步字的独特码序列: a unique sequence of pulses called synchronization word 地面系统:terrestrial system脉冲的“有”或“无” : the presence or absence of the pulses高速的电子开关: a high-speed electronic switch时分多路复用器:the time division multiplexer时分多路复用:Time Division Multiplexer异步串行数据传输asynchronous 异步的serial串行的, 串联的transmission传输, 发送interface接口receive接收, 收到synchronize 使) 同步, ( 使) 同时或同速进行period周期, 循环, 时期, 阶段, 时间间隔, 时间clock时钟transmitter发送器, 发射机receiver接收器, 接收机necessary必要的, 必需的, 必须做的link连接, 耦合, 线路, 链路teleprinter电传打字机telephone电话Morse code莫尔斯电码signal信号native当地的, 天生的fundamental基本的, 根本的, ( 十分) 重要的split分开, 劈开, 分割, 分离incoming进来的, 入射的, 输入的stream流, 束, 潮流, 倾向individual分别的,各个的,单独的,个体的,独立的unit单元, 元件, 成分, 装置, 设备, 组( 合) ,机组, 块体group组合, 分组, 群聚, 聚集character字母, 字符, 符号, 字, 电码组合, 角色, 人物dot圆点, 小数点dash破折号, 长划线, 猛冲, 冲锋separate( 使) 分离, ( 使) 分隔, 隔开, 区分, 分类intersymbol码间的, 符号间的intercharacter字符间的duration持续时间, 延续时间examine检查, 审查, 实验, 研究, 探讨, 测验, 考试divide 分开, 分配, 分割, 划分, 等分ingenious精巧的, 精致的format格式, 形式orient定向, 定( 方) 位, 标定, ( 使) 适应, 朝向invariably不变地, 总是, 一定, 永恒地comprise包含, 包括, 由……组成plus 加上, 加, 外加; a . 正的control控制frequently时常, 频繁地correspond相当, 对应, 符合, 一致correspond to 相当于, 与……相对应, 与……相吻合encode编码initially最初, 开头, 一开始idle [ aidl ] a . 闲置的, 空闲的traditionally传统地, 惯例地mark level 信号电平logical逻辑的space level 空号电平successive连续的, 顺序进行的, 逐次性的parity奇偶性calculate计算continually屡次地, 再三地, 频频地, 连续地monitor监视( 器) , 监测( 器) detect发觉, 觉察; n . 检测器, 侦察器sample样品, 取样; vt . 抽样, 采样assemble集合, 收集, 装配, 组装flag旗, 标志, 标志位critical决定性的, 关键的, 危险的, 临界的aspect方面, 方位, 外貌, 样子edge边, 边缘, 界限, 边界trigger触发, 起动, 扣扳机, 发射nominal标称的, 额定的thereaf ter此后, 其后situation位置, 地点, 场所, 形势, 情况, 环境, 局面obvious明显的, 明白的, 显而易见的disadvantage不利条件, 不利方面, 有害, 缺点whenever无论何时, 随时, 每当terminal终端dump倾倒, 翻卸, 转储binary二进制的串行接口serial interface 显示终端CRT terminal发送器与接收器transmitter and receiver数据传输data transmission 数据流data stream闲置状态the idle state 传号电平mark level空号电位space level 起始位start bit 停止位stop bitT秒的持续时间duration of T seconds 奇偶校检位parity bit错误标志error flag 传输错误transmission error下降沿fallinf edge 符号间的空格intersymbol space接收机的定时receiver timing 本地时钟local clock磁带magnetic tape 控制比特control bit逻辑1电平logical 1 level 二进制数据binary data明显的缺点obvious disadvantage异步串行数据传输asynchronous serial data transmission最为流行的串行接口the most popular serial interface所传送的数据the transmitted data发送器与接收器的时钟the clocks at the transmitter and receiver电传机的时代the era of teleprinter一个字符的点和划the dots and dashs of a character符号间空格持续时间的三倍three times the duration of intersymbol space被称为字符的比特组the group of bits called characters由7或8个比特的信息组成的固定单元the invariable units comprising 7 or 8 bits of inf ormation由接收机本地产生的时钟a clock generated locally by the receiver在字符后所收到的奇偶校检位the received parity bit following the character起始位的下降沿the falling edge of the start bit数据链路面向字符的特性the character-oriented nature of the data link数据通信undergrounda .地下的via.经过, 通过keyboard键盘visual视觉的, 光学的originate发生, 开始originating call 发端呼叫assembly.组合, 装配temporary暂时的, 临时的temporarily临时地compatible一致的( wit h ) , 兼容的appropriate适当的synchronize使同步derive取得, 得到, 由……导出capacity容量, 能力concern所关切的事, 担心slot狭槽, 缝隙time slot 时隙al location分配, 配给物employ使用simultaneous同时发生的, 同时的linear.线性的, 一次的at tenuation 减少, 衰减ideal理想的ideally .理想地impairment .消弱, 损伤irregulari y不规则tolerate 容忍, 默认compensate补偿, 酬报anyway= anyhow 不管怎样,无论如何redundant过多的, 多余的, 冗余的inherent内在的, 固有的al leviate 减轻, 缓和reverse.颠倒的, 相反的successive连续的whereas而, 却, 反之, ( 公文用语) 有鉴于arbitrary任意的地下电缆underground cable 通信卫星communication satellite微波设备microwave facilities调制器与解调器modulator and demodulator 缓冲器buffer定时信号timing signals 同步脉冲synchronization pulses时隙time slot 移位寄存器shift register传输媒体transmission medium 线形衰弱linear attenuation信息安全information security 数据终端data terminals某种类型的数据转换设备some type of data conversion equipment视频显示终端visual display terminal称为数据调制解调器的双向数据发送接收机two-way data transmistter-receiver called a data modem全双工的数据传输系统full-duplex data trandmission system由数据处理器的运算速率所决定的速率the rate determined by the operating speed of t he data processor由接口部件来的定时信号timing signals from the interface assembly磁心存储器magnetic core memories线性衰减和时延特性linear attenuation and delay characteristics传输损伤transmission impairments语音中的冗余特性the redundant nature of speech在数据发送器中的编码过程coding process in the data transmitter二进制的不归零信号binary nonreturn-to-zero signal互联网giant 巨大的collection.收集, 集成address地址backbone支柱, 骨干, 主干contractor订约人, 承包商survive幸免于, 从……中逃生disaster灾难, 天灾conference会议, 讨论会purpose.目的, 意图complex合成物, 综合企业exactly确切地, 精确地repository仓库, 资源丰富的地方resource资源facil ity设备, 工具entertainment娱乐, 乐趣explosion爆炸, 扩张, 激增majority多数, 大多数account账目, 账户choose选择, 挑选at tach缚, 系, 附加modem调制解调器dictate命令, 支配satisfy使满意definite明确的, 确切的, 肯定的requirement需要, 要求convenient方便的, 便利的hypertext超文本interface接口, 界面ambi tious有抱负的, 雄心勃勃的trigger发射, 引起icon画像, 肖像, 图标stuff原料, 资料, 东西community团体, 社会tradition传统, 惯例网络资源:network resource 信息服务:information services远程终端:remote terminals 互联的系统:interconnected systems命令:command 电子邮件:electronic mail 主机:host 无线信道:wireless channels 搜索工具:searching tools 用户界面:user interface 存取:access文本信息:textual messages 协议:protocol 超文本协议:hypertext protocol分布在全世界的计算机的巨大网络:gaint network of computers located all over the wor ld 主干系统:backbone system 全国范围的网络:nationwild network电子会议:electronic conferences 实时对话:live conversation最大的信息库the largest repository of the computers on the net网络设备资源:network facilities resources在网上的绝大多数计算机:the vast majority of the computer on the netUNIX操作系统:the UNIX operating system在因特网和你的PC机之间传送数据的方法:a way to move data between the internet a nd your PC 方便的搜索工具:the convenient searching tools联网的超文本协议:the network hypertext protocol光纤通信介绍fiber = fibre光纤, 纤维emerge出现, 形成, 浮现emergence浮现, 出现haul用力拖; n . 拖, 拉, 拖运的距离long-haul 长运距的, 长途的trunk干线, 中继线, 中继线路, 局内线dominate支配, 统治; vi 处于支配地位account账目, 报道; vi . 说明account for 解释, ( 数量等) 占rationale( 某事物的) 基本理由, 理论基础clad穿衣的, (金属)包层,覆盖层, ( 用壳) 包盖bundle捆, 束endoscopy内窥术sil ica石英, 二氧化硅publication发表, 出版物cite引用, 举( 例) community 团体, 社会inevitable不可避免的, 必然的, 合情合理的evolve使发展, 推论; vi . 进展, 发展, 进化figure外形, 图形, 人物, 数字fragi le脆的, 易碎的marketplace市场barrier隔板, 障碍, 界限formidable可怕的, 难以应付的, 庞大的consequence结果, 结论accelerate加速rugged强壮的, 艰苦的threshold门槛, 阈, 阈限gal lium aluminum arsenide 镓铝砷激光器photodetector光电探测器, 光电检测器project设计, 抛出; n . 项目, 方案rel iabil ity可靠性trial( 好坏、性能等的) 试验AT& T(American Telephoneand Telegraph Company) 美国电话电报公司commitment作为, 赞助, 委托intercity城市之间的, 市际的gigabit吉比特, 千兆比特spectral pure a . 光谱纯的distributed-feedback(DFB) laser 分布反馈激光器potential潜力, 可能prominent突出的, 杰出的, 重要的metropoli tan首都的, 主要城市的hierarchy 分类等级upgrade使升级wideband n . 宽频带, 宽波段entertainment招待, 娱乐broadband n . 宽频带, 宽波段feasible可实行的, 行得通的, 可能的standard标准光纤通信:optical fiber communications 光源:light source 波长:wavelength激光器:laser 色散:dispersion 传输介质:transmission medium多模光纤:multi-mode fiber 长途干线:long-houl trunks 单模光纤:singer-mode fiber 带宽:bandwidth 带宽用户:wideband subscriber 纤维光学:fiber-optics商用技术:commercial technologe 门限电流:threshod current光检测器:photodetector 波分复用:wavelength multiplexing纤维光网络:fiber-optic network 视频带宽:video bandwidth长途传输:long distance transmission 中继距离:repeater spacing已装光纤的总长度:the total length of installed fiber长途通信系统:long-haul telecommunication system低衰减的石英纤维:the low-loss silica fiber衰减接近瑞利极限的光纤:fibers with losses approaching the Rayleigh limit室温下的门限电流:room temperature threshold currents较长波长区:the longer wavelength region 用户接入工程:subscriber access project 部件性能和可靠性的改进:improvements in component performance and reliability已安装的光纤系统的数据速率:data rates for installed fibre optic system每秒吉比特:gigabit per second range 波分复用:wavelength multiplexing带宽用户环路系统:widebend subscriber loop system多纤连接器:multifibre connectors 设计寿命:projected lifetime光源:light source 分布反馈式激光器:distributed-feedback laser信息容量:information capacity 交换体系:switching hierarchy带宽业务:broadband services同步数字系列hierarchy体系, 分层结构synchronous同步的approve批准, 审订, 通过tributary支流的, 从属的, 辅助的map绘制, 设计, 映射, 变换node节点, 结embark从事, 开始搞provision准备, 预备essence本质,核心in essence 本质上, 实质上advanced先进的, 前进的, 高深的maintenance维护, 保养approximately近似的, 大约地procedure过程, 步骤, 程序, 手续overlay覆盖层, 涂盖层accommodate 提供, 容纳unify使一致, 使一体configure使成形, 使具形体, 构成gateway门口, 入口, 通道mode方式, 样式, 模式variety变化, 多样化, 各种各样cornerstone基石, 柱石, 基础permanent永久的, 持久的lease 出租virtual虚的, 假想的, 虚拟的container容器section节, 段, 部分dimensional维的, 度的marker记号, 符号, 标志intact未经触动的( 地) ,完整的( 地) , 未受损的(地) capacity容量, 能力, 容纳量distinct不同的, 有区别的, 清晰的, 明显的readily很快地, 容易地, 简便地, 直接地accessible可接入的overhead开销, 经常性的开支assemble 集合, 装配, 聚集同步数字系统:synchronous digital hierarchy 国际标准:international standard信号格式:signal format 网络节点接口:network node interface支路信号:tributary signals 数字交叉连接:digital cross-connection网络管理:network management 网络维护:network maintenance网络运营者:network operators 传输速率:transmission rate支路映射:tributary mapping 灵活性:flexibility 用户业务:subscriber services覆盖层:overlay levels 制造商:manufacturer同步传输帧:synchronous transmission frame 线路终端复用器:line terminal multiplex er 分插复用器:add-drop multiplexer 再生中继器:regenerator灵敏度:sensitivity 虚容器:virtual container 成帧字节:framing bytes段开销:section overhead 端到端传输:end-to-end transmission误码监视:error monitoring 信号处理节点:signal processing nodes净负荷:payload 指针:pointer 同步传输系统:synchronous transmission system 覆盖nni的标准:the standard covering the NNI国际标准接口:the international standard interface直接同步复用:direct synchronous multiplexing灵活的通信联网:flexible telecommunication networking点对点的传输技术:point-to-point transmission technology先进的网络管理:advanced network management不同厂家提供的设备:the equipment supplied by different manmufacturersSDH提供的灵活性:the flexibility provided by SDH同步复用设备的运营者:operator of synchronous multiplexers电信联网:telecommunication networking支路信号:tributary signals 维护能力:maintenance capabilities统一的电信网络基础结构:unified telecommunication network infrastructure组件:building blocks 终端复用器:terminal multiplexer贯通方式:through-mode fashion 同步数字交叉链接:synchronous DXC可变带宽:arying bandwidth 各个支路信号:individual tributary signals传输系统:transport system 光载体:optical carrier二维图形:2-dimensional map 传输次序:the order of transmission波分复用visionary幻想家, 梦想家contribute捐献, 贡献significant重大的, 效果显著的, 具有特殊意义的property所有物, 房产, 所有权fundamental基础的, 重要的, 本性的span跨过, 延伸twinkle闪烁, 闪耀, 眨眼equivalent相同的, 同等traffic交通, 通信量, 交易ample充足的, 充分的, 宽敞的evidence证据, 证词phenomena单数为p h en omen o n n . 现象unify使一致, 使化一, 统一video电视的, 视频的, 录像的striking 引人注意的, 显著的advance前进, 提升, 进展magni tude广大, 巨大, 重要corresponding符合的, 对应的,一致的~ly adv . commercial商业的, 商务的demonstrate示范, 展示, 演示rainbow虹, 彩虹approximate近似的, 大概的~ly adv . boost上推, 增加, 提高el iminate除去, 淘汰considerable相当大的, 相当多的simultaneous同时发生的,同时存在的,同时的~ly adv . equalization相等, 均等, 平等optimize乐观的考虑, 使尽可能完善extraordinary非常的, 特别的, 非凡的exacting苛求的, 严格的differentiation分化, 变异, 演变medical医学的, 医术的, 医疗的infrastructure基础, 基础结构exponential指数的, 幂的constitute构成, 组成, 设立majority多数, 半数以上in this regard 在这一点上, 关于此事flexible易弯曲的, 可变通的, 灵活的domain领域, 领地, 范围wrapper包装者, 包装物, 覆盖物standardize使与标准比较, 使合标准, 使标准化twofold两倍的, 两重的identify使等同于, 识别, 鉴定unveil使公诸于众, 揭露, 展出microscopic显微镜的, 微小的, 细微的implement贯彻, 完成, 履行sophisticate使复杂, 使精致intell igence智力, 只能, 理解力router路由器restoration恢复, 复位, 复原aspect样子, 外表, 方面enormous巨大的, 庞大的metropoli tan大城市的, 大都会的materialize使物质化, 使具体化residential居住的, 长住的, 居留的deploy展开, 调度, 部署对光特性的理解:the understanding of the property of light基本重要性:the fundamental important想象今天的通信系统:to imagine the communication system of today光的高速公路:the highway of light巨量的信息:the massive amount of information采用通信新技术:to adopt new communication technology大量的视频信息:the large amounts of video information波分复用:the wave divide multiplexing只发送单个波长:to send only one wavelength传输大量的波长:to transmit a large amount of wavelength无差错传输:the error-free transmission 自愈特性:the self-healing propertys 直接接入光网络:to access directly to the optial network视频信息:the video information导致WDM革命的主要进展:the major advance that led to the revolution光放大器的发明:the invention of the optical amplifier下一段光纤:the next span of fiber提高所有波长信号的功率:to boost the signal power of all wavelength在光放大器方面的进展:the advances in optical amplifier增益均衡技术的发展:the development of gain equalization techniques多波长传输:the multiple-wavelength transmission无线系统的增长:the growth of various application各种各样的业务:the wide various application处理各种业务类型:to handle various types of traffic全光交叉连接:the all-optical cross-connect寻呼系统的发展means方法, 手段, 工具advantag优势, 利益availabi lity可用性, 可得性, 有效, 在场assume假定, 设想dramatic戏剧的,鲜明的consequence结果, 后果essential本质的, 必不可少的complement补充, 补足message同……通信联系, 发信号传达sophisticated复杂的, 尖端的embryonic胚胎的, 开始的paging寻呼acoustical听觉的, 声学的premise( 复) 房屋( 及附属建筑) switchboard交换台perpetual永远的, 永恒的extension延伸, 扩大unquestionable毫无疑问的, 确实的miniaturization小型化instantaneous瞬间的, 即刻的complex复杂的, 综合的dedicate奉献, 把……用在……oblige迫使, 责成designate指明, 指定beep发嘟嘟声substantial多的, 实质的agglomeration成团, 联片tributary附属, 辅助portable轻便的, 手提的cellular蜂窝状的packet一小批, 分组quali tative质量的geostationary与地球相对位置保持固定不动的geostationary satel lite ( 同步) 通信卫星quasi准, 半( 前缀) penalty障碍, 不利后果antenna 天线compensate补偿, 赔偿preference偏爱, 优先prohibitive禁止的, 抑制的proximity最近, 接近segment部分, 切片通信手段:communication means 被叫人:called person紧急通信:urgent communications 移动电话网:mobile telephone network电话交换台:telephone switchboard 寻呼业务:paging service电子电路:electronic circuitry 无线传输:wireless transmission无线发射机:wireless transmitter 个人代码:personal codes 服务区:service area 单向通信:one-way communication 寻呼用户:paging users 顾客:customer技术进步:technological progress 系统的效率:efficiency of the system专用的无线网络:dedicated wireless network 终端设备:terminal equipment全球覆盖:global coverage 无线增益:gain of the antenna 空间站:space station 通信网络的运行:the operation of a communication network有线的和移动的电话网络:the wired and mobile telephone network光和声音的信号装置:optical and acoustical signaling devices本地电话交换台的接线员:the operator of a local telephone switchboard第一代寻呼系统:the first generation of paging system利用无线传输的寻呼系统:the paging system using wireless transmission专用的无线接收机:the dedicated radio receiver社会和经济效益:social and economic advantages电子电路的小型化:the miniaturization of electronic circuitry价格效率比:cost efficiency 小型无线电接收机:the miniature radio receiver显示能力:display capability 全球覆盖:global coverage空间站的天线增益:the space station antenna gain地球同步轨道卫星:geostationary orbit satellite用户终端:user terminal蜂窝式移动电话系统cellular细胞的, 蜂窝状的, 单元的mobile运动的deploy 展开, 使用, 推广应用operational操作( 上) 的, 工作的,使用的limitation界限, 极限, 局限性, 能力有限conventional传统的, 普通的, 会议的performance执行, 完成, 性能, 特性al location配置, 分布, 规定federal联邦的, 联合的;Federal Communications Commission (FCC)美国联邦通信委员会approach向……接近, 探讨; n . 接近,手段,方法al locate分配, 配给; n . 分配, 配给物geographic地理的, 地区的hop使跳过microprocessor微处理机, 微处理器minicompute小型计算机feature形状, 特色, 部件, 零件Large-Scale Integrated (LSI) circuit 大规模集成电路transceiver收发两用机advanced在前面的, 高级的, 先进的encourage鼓励, 赞助, 促进pursue追赶, 追踪, 追求, 继续authorize授权, 委托, 允许feasibi li ty现实性, 可行性severe严重的, 困难的, 简练的vicinity附近, 邻近extend延伸, 扩展multipath多路, 多途径; a . 多路的, 多途径的fading.衰落, 消失, 衰减multipath fading 多径衰落cell 小房间, 蜂房的巢窒, 单元site地点, 基地, 场所coordinate配合的, 协调的; vt . 使配合, 调整switch开关, 接线器, 交换机;交换, 转换interface边界, 接口zone区域, 范围, 环带billing计费subsystem 系统的分部, 子系统, 辅助系统simultaneous同时发生的, 同时做的simultaneously administration管理, 经营supervision监督, 管理wireline 金属线路, 有线线路radius半径范围, 半径, 径向射线蜂窝式移动电话:cellular mobile telephone 服务性能:services performance频谱:frequency spectrum频带:frequency band微处理器:microprocessor移动手机:mobile unit广播业务:broadcast servise天线:antenna子系统:subsystems移动用户:mobile subscriber 服务能力:service capability利用率:utilization带宽:bandwidth 单边带:single-sideband扩频:spread spectrum 大规模集成电路:large scale integrated circuits蜂窝点:cellular site蜂窝交换机:cellular switch无线机架:radio cabinet呼叫处理:call processing频谱利用率:frequency spectrum utilization有限的指定频带:the limited assigend ferquency band 服务区:servise area复杂的特性和功能:complicated features and functions大规模集成电路技术:large-scale integraesd circuit technology试验性的蜂窝系统:developmental cellular system中央协调单元:central coordinating element 蜂窝管理:cellular administration传统移动电话的运行限制:operational limitiation of conventional mobile telephone syst em 有限的服务能力:limitied service capability无线通信行业:radio communcation industry可用的无线电频谱:available radio frequency spectrum所分配的频带:the allocated frequency band 移动收发信机:mobile transceiver技术上的可行性:techological feasibility 严格的频谱限制:severe spectrum limitations 调频广播业务:FM broadcasting services 传播路径衰耗:propagration path loss多径衰耗:multipath fading 电话公司地方局:telephone company zone offices全球移动通信系统GSMpersonalize使个人化convenient便利的, 方便的rapidity快, 迅速severe严格的, 严重的restrict限制, 约束vary改变, 变化, 不同coaxial同轴的, 共轴的interface分界面, 接口conversion变化, 转化complex合成的, 复杂的, 综合的spectrum谱, 频谱vex [ veks ] v . 使烦恼, 使恼火al location分配, 配给generation代, 一代dominate支配, 统治cellular多孔的, 蜂窝状的Simultaneous come into play 同时发生的, 一齐的起作用interference干涉, 打扰maximum最大量, 极限hexagon六角形, 六边形transceiver无线电收发信机register记录器, 寄存器charge要价, 收费uplink上行链路downlink下行链路access接近, 进入burst 突发, 一阵迸发overhead管理费, 开销handover移交, 越区切换algorithm算法entire整个的, 全部的roam漫步, 漫游in addition to 除……之外facsimi le传真in concert 一致, 一齐perspective远景, 前途compatible适合的, 兼容的个人通信personal communication 通信标准communcation standrads固定电话业务fixed telephone services 网络容量network capability移动交换中心mobile switching center 国际漫游international roaming宽带业务broadband services 接口转换interface conversion频谱分配frequency allocation 模拟方式analogue mode蜂窝通信原理cellular communcation principle 拥塞jamming蜂窝裂变cellular splitting 基站base station 寄存器register收费功能billing function 接入方法access method突发脉冲传输方式brusty transimission mode 管理信息overhead information切换算法handover algorithms 短消息服务short message services技术规范technical specification 全接入的通信系统total aceess communcation system global mobile communcation system 全球移动通信系统time division multiple access 时分多址facsimile and short message services 传真和短消息服务fixed communcation networks 固定通信网络a more personalized system 更加个性化的系统the cost and quality of the link 链路的价格和质量market growth 市场的发展fixed telephone service 固定电话服务coxial cable 同轴电缆interface convision 接口转换cellular communcation priciple 蜂窝通信原则frequency reuse and cell splitting 频率复用和蜂窝裂变cochannel interference 共信道干扰theoretical spectual capability 理论上的频谱容量micro-cellular system 微蜂窝系统base station transceiver 基站收发信机subscriber register 用户寄存器burst transmission mode 突发脉冲传输模式overhead information 开销信息advanced handover algorithms 先进的切换算法facsimile and short message services 传真和短消息服务the GSM technique specications GSM技术规范说明电路交换与分组交换destination目的地, 终点allocate分配, 分派, 配给release释放, 放松, 发布jargon行话, 土语manipulate处理, 操纵seize抓住, 占领, 俘获proceed进行, 继续inform 通知, 告诉intervention干预, 干涉, 防碍subnet子网, 分网block一批, 一组, 一块header头, 头部checksum检验和, 检验项regard与……有关, 涉及at tach缚, 系, 捆entirely完全地, 彻底地accordingly相应地queue行列, 长队variat ion变动, 变化, 变更incur招致, 惹起guarantee保证, 担保steady稳定的, 平稳的, 不变的amort ize缓冲, 分摊bursty突发性, 突发randomness 随机, 机遇constraint强迫, 强制, 制约relatively相对地, 比较地response回答, 响应dedicated专用的assign分配, 指派, 委派util ization利用dynamically动态地, 有生气地benefit利益, 好处, 恩惠simultaneously同时地, 同时发生consecutive连续地, 连贯地pipeline用管道输送procedure过程, 步骤entity存在, 实体电路交换circuit switching 分组交换packet switching 报文交换message switching 子网subnet 信头header 目的地址destination address 误差控制error control 存储转发方式store-and-forward manner 突发性bursty传输时延transimission delay 中间交换设备intermediate switching equipment 交换技术switching technique返回信号return signal 报文处理机message processor给定最大长度given maximum length 信息转移information transfer随机性random专用电路dedicated circuit 电路利用率channel ultilizationthe capability of soring or manipulating user's data 存储和处理用户数据的能力the special signaling message 特定的信令信息a well defined block df data callde amessage 被精心定义的称为报文的数据块the information regarding the source and destination address 涉及源和目的地址的信息the computer referred to a message processor 叫做报文处理器的计算机the store-and-forward transmission technique 存储转发传输技术the dynamic allocation of bandwith 带宽的动态分配the overall transmission delay of message 报文整个的传输时延switching technique 交换技术ciruit switching 电路交换message switching 报文交换total path of connected lines 连线的整个通路source-destination pair 源到目的地的一对communication parties 通信各方transmission unit 传输单元intial connection cost incurred in setting up the circuit 在建立电路时的起初连接成本low delay constraint required by the user 用户所需的最短时延的限制the fixed dedicateded end-to-end circuit 固定专用的端到端电路low channel ultization 低的电路利用率异步转移模式ATMasynchronous异步的multiplex多路复用initial 最初的, 开始的universal宇宙的, 普遍的, 通用的packet小包, 分组irrespective不考虑的, 不顾的underlying在下的, 基础的dual双的, 二重的identification识别, 鉴定, 验明virtual虚的simplicity简单, 简明protocol草案, 协议cell小房间, 信元, 小区megabit兆比特recommendation推荐, 建议ratify批准, 认可forum论坛, 讨论会expedite加快, 促进specification规范, 说明书approximation近似traditional传统的, 惯例的equivalent相当的, 等效的dynamical能动的, 动态的rigidly坚硬的, 僵硬的occupy占领, 占用infrastructure基础, 基础结构coordinate使同等, 协调enthusiam热情, 积极性impact冲击, 效果, 影响due to 由于particular 特殊的, 特定的variable易变的, 可变的essential本质的, 必不可少的simplify简化, 精简optimum 最佳条件statistical统计的, 统计学的private私人的, 个人的upheaval激变, 剧变advent出现, 到来analogue模拟异步转移模式asynchronous 逻辑信道logical channel 虚电路virtual circuits虚路径virtual paths 建议recommendation 网络层network level业务与应用层service and application 虚连接virtual connection信息高速公路information superhigh way 点播电视video-on-demand统计复用statistical multiplexing 数字化的信息digital information标识符identifer 协议protocols 网络节点network node宽带网broadband network ATM论坛ATM forum 面向未来future-proofed图象编码image encodeing 虚拟专用网virtual private network数据处理data processing 被叫做信元的短的分组short packets called cells每秒几百兆比特的速率bit rates of several hundred megabits a second独特的复用方法unique multiplexing method任何两个终端之间的物理连接the physical connection between any two terminals交互式的视频业务interactive video services多媒体业务的自然载体 a nature vehicle for multimedia services运营者和用户当前和未来的要求the current and future requirement of both perators a nd users 高比特率信道的交换技术the technique for switching high bit rate channel 异步转换模式asychornous transfer mode复用和交换技术multiplexing and switching technique所承载的传输类型the underlying type of transmission 双重标识dual identification 虚电路virtual circuit 虚路径virtual path信元在网络节点上的转移the transfer of cells to the network nodes每秒几百爪比特hundreds megabits a secondI.121建议recommendation I.121 服务质量the quality of service与实际需求成比例in proportion to the exact requirement网络所传送的应用和业务the applications and service transported over a network构成虚网络的能力the ability to construct virtual networks低价高效的利用网络设施cost-effective use of infrastructure面向未来的future-proofed协调传送不同业务的不同网络coordinating different networks carrying different service s 未来的信息高速公路的基本部件essential components of future information sup erhighways 统计复用statistical multiplexing资源的最佳使用optimum use of resources 虚拟专用网virtual private networks 多媒体Multimediadescribe描述, 形容mixture混合, 混合物consequent作为结果的, 随之发生的confusion混乱, 混乱状态opportunity机会, 良机literal ly逐字地, 字面地in a sense 从某种意义上说immerse沉浸, 使陷入environment环境, 周围presentation呈现, 展示visual视觉的audio听觉的, 声音的enormous巨大的, 庞大的facility设备, 工具majority多数moni tor监视器mature成熟的represent描述, 讲述compression压缩, 浓缩immense广大的, 巨大的photograph照片professional职业的, 专业的definition 定义, 清晰度algorithm算法at tempt尝试, 试图upgrade升级, 上升inferior劣等的, 差的challenge 挑战pixel像素, 像元archi tecture结构, 组织trunk干线server服务器instantly立刻, 即刻estimate估计交互环境interactive environment 视频压缩video compressin高清晰度电视high definition television 数字信号处理器digital signal processor点播业务on-demand services 视频服务器video servers硬件、软件和应用hardware,software and applications 存储storage全活动图象full motion picture 视频编码器vision encodermixture of hardware,software and applications 硬件、软件和应用层interactive environment 交互环境personal desk top computers 个人桌面电脑。
福建省泉州市⾼考英语⽂章突破⼀轮训练(22)泉州市2014⾼考英语⽂章突破⼀轮训练(22)及答案阅读理解、专题训练(**)、说明⽂的阅读(2)阅读下列短⽂,然后按要求完成读写任务Microwaves may be great at warming up food,but whatabout warming people?Using microwaves to directly heat owners of a room would save much of the energy wasted by heating walls and furniture.And despite popular ideas about microwaves,this technique would be safe,according to Charles R.Burlier of the Microwave Research Center in Marlborough,New Hampshire.Low-power microwaves only penetrate (贯穿)the skin (low-power microwave penetration in a ham is about 0.2 inches,for example)and with no negative effects.To test this idea,Buffler subjected himself to microwaves in a special room using a standard 500-watt,2,459 MHz magnetron (磁控管).He found that a person will start to feel warmth at about 20 milliwatts per square centimeter (mw./sq.cm.);a satisfactory feeling of warmth occurs between 35 and 50mw./ sq.cm.By comparison,a person standing in noonday summer sun feels the amount of 85 mw./ sq.cm.And a frozen meat pie in your microwave oven receives about 1,000 mw./ sq.cm.In houses of the future,each room could be provided with its own magnetron,says Buffler.When you stepped into the living room,for example,a motion detector (运动感应器)would turn on the magnetron,filling the room with low-power micr owaves.In the same way that a microwave oven heats up a hamburger,but not the plate it's on,you would feel warmth from the microwaves without changing the temperature of your coffee table.You could,however,make your favorite easy chair even more comfortable by treating it with a radiation-absorbing chemical.While it might be some time before homeowners are comfortable enough with the idea to set up whole-body microwave heaters in houses,Buffler says microwaves may attract livestock(家畜)/doc/5d15849a59fafab069dc5022aaea998fcc2240ae.html mbs that are born outdoors in winter,for example,are frequently lost to cold.Microwaves could warm the lambs safely and quickly.Ⅰ.以约30词概括⽂章⼤意____________________________________________________________________________________________________________________________________________________________________________________________________________________________Ⅱ.根据短⽂内容选择最佳答案1.Which of the following can tell the main idea of the passage?A.A new heating system. B.A new microwave oven.C.A popular technique. D.The magnetron.2.According to Paragraph 2,which of the following does not describe the characteristics of a microwave heater?A.It directly heats people in a room.B.It heats walls and furniture in a room.C.It is safe.D.It saves energy.3.The test conducted by Buffler shows that when a person feels comfortable warmth,he receives about ________. A.20 mw./ sq.cm. B.40 mw./ sq.cm.C.60 mw./ sq.cm. D.85 mw./ sq.cm.4.According to Paragraph 4,which of the following fills the room wi th low-power microwaves?A.The magnetron.B.The motion detector.C.The microwave oven.D.The radiation-absorbing chemical.5.Which of the following statements about microwave heaters would Buffler most probably agree with?A.Microwave heaters will soon be widely used by homeowners.B.Microwave heaters sometimes make people feel uncomfortable.C.Perhaps microwave heaters will be first used by livestock farmers,who wish to protect their lambs in winter.D.Microwave heaters cannot be accepted by the public because they are somewhat unsafe.参考答案ⅠThe passages introduces a new heat system which can heat people directly by using a magnetron controlled by a motion detector.Thus we can save energy wasted by heatingwalls and furniture.(32 words)Ⅱ1.解析:全⽂介绍了⼀种新的加热系统,包括它的⼯作原理、使⽤⽅法等。
whatsoever=whatever0switchboard(电话)交换台bipolar(电子)双极的premise(复)房屋,前提cursor(计算机尺的)游标,指导的elapse(时间)经过,消失vaporize(使)蒸发subsystem(系统的)分部,子系统,辅助系统metallic(像)金属的,含金属的,(声音)刺耳的dispatch(迅速)派遣,急件consensus(意见)一致,同意deadline(最后)期限,截止时间tomographic X线体层摄像的alas唉,哎呀cluster把…集成一束,一组,一簇,一串,一群encyclopedia百科全书millionfold百万倍的semiconductor半导体radius半径范围,半径,径向射线half-duplex transmission半双工传输accompaniment伴随物,附属物reservation保留,预定quotation报价单,行情报告,引语memorandum备忘录redundancy备用be viewed as被看作…be regards as被认为是as such本身;照此;以这种资格textual本文的,正文的verge边界variation变化,变量conversion 变化,转化identity标识;标志criterion标准,准则in parallel on并联到,合并到juxtapose并置,并列dialing pulse拨号脉冲wave-guide波导wavelength division multiplexed波分复用baud rate波特率playback播放(录音带,唱片)no greater than不大于update不断改进,使…适合新的要求,更新asymmetric不对称的irrespective不考虑的,不顾的inevitably不可避免的inevitable不可避免的,不可逃避的,必定的segment部分abrasion擦伤,磨损deploy采用,利用,推广应用take the form of采用…的形式parameter参数,参量layer层dope掺杂FET(field effect transistors)场效应管audio recording唱片ultra-high-frequency(UHF)超高频in excess of超过in excess of超过hypertext超文本ingredient成分,因素ingredient成分,组成部分,要素metropolitan-area network(WAN)城域网metropolitan area network(WAN)城域网,城市网络congestion充满,拥挤,阻塞collision冲突extractive抽出;释放出extract抽取,取出,分离lease出租,租约,租界期限,租界物pass on传递,切换transmission传输facsimile传真innovative=innovatory创新的,富有革新精神的track磁道impetus促进,激励cluster簇stored-program control(SPC)存储程序控制a large number of 大量的peal大声响,发出supersede代替supplant代替,取代out-of-band signaling带外信号simplex transmission单工传输monochromatic单色的,单色光的,黑白的ballistic弹道的,射击的,冲击的conductor导体hierarchy等级制度,层次infrastructure底层结构,基础结构geographic地理的,地区的geographically地理上GIS(ground instrumentation system)地面测量系统ground station地面站earth orbit地球轨道extraterrestrial 地球外的,地球大气圈外的Land-sat地球资源卫星rug地毯,毯子ignite点火,点燃,使兴奋electromagnetic电磁的inductive电感arc电弧telephony电话(学),通话dielectric电介质,绝缘材料;电解质的,绝缘的capacitor电容telecommunication电信,无线电通讯scenario电影剧本,方案modem pool调制解调器(存储)池superimposing叠加,重叠pin钉住,扣住,抓住customize定做,定制monolithic独立的,完全统一的aluminize镀铝strategic对全局有重要意义的,战略的substantial多的,大的,实际上的multi-path fading多径衰落multi-path多路,多途径;多路的,多途径的multi-access多路存取,多路进入multiplex多路复用multiplex多路复用的degradation恶化,降级dioxide二氧化碳LED(light-emitting-diode)发光二极管evolution发展,展开,渐进feedback反馈,回授dimension范围,方向,维,元scenario方案scenario方案,电影剧本amplifer放大器noninvasive非侵略的,非侵害的tariff费率,关税率;对…征税distributed functional plane(DFP)分布功能平面DQDB(distributed queue dual bus)分布式队列双总线hierarchy分层,层次partition分成segmentation分割interface分界面,接口asunder分开地,分离地detached分离的,分开的,孤立的dispense分配allocate分配,配给;配给物centigrade分为百度的,百分度的,摄氏温度的fractal分形molecule分子,微小,些微cellular蜂窝状的cellular蜂窝状的,格形的,多孔的auxiliary storage(also called secondary storage)辅助存储器decay腐烂,衰减,衰退negative负电vicinity附近,邻近vicinity附近地区,近处sophisticated复杂的,高级的,现代化的high-frequency(HF)高频high definition television高清晰度电视chromium铬annotate给…作注解in terms of根据,按照disclosure公布,企业决算公开public network公用网functionality功能,功能度mercury汞resonator共鸣器resonance共振whimsical古怪的,反复无常的administration管理,经营cursor光标(显示器),游标,指针optical computer光计算机photoconductor光敏电阻optical disks光盘optically光学地,光地wide-area networks广域网specification规范,说明书silicon硅the international telecommunication union(ITU)国际电信联盟excess过剩obsolete过时的,废弃的maritime海事的synthetic合成的,人造的,综合的synthetic合成的,综合性的rational合乎理性的rationalization合理化streamline合理化,理顺infrared红外线的,红外线skepticism怀疑论ring network环形网hybrid混合物counterpart伙伴,副本,对应物electromechanical机电的,电动机械的Robot机器人Robotics机器人技术,机器人学accumulation积累infrastructure基础,基础结构substrate基质,底质upheaval激变,剧变compact disc激光磁盘(CD)concentrator集中器,集线器centrex system集中式用户交换功能系统converge on集中于,聚集在…上lumped element集总元件CAI(computer-aided instruction)计算机辅助教学computer-integrated manufacturing(CIM)计算机集成制造computer mediated communication(CMC)计算机中介通信record记录register记录器,寄存器expedite加快,促进weight加权accelerate加速,加快,促进categorize加以类别,分类in addition加之,又,另外hypothetical假设的rigidly坚硬的,僵硬的compatibility兼容性,相容性surveillance监视surveillance监视retrieval检索,(可)补救verification检验simplicity简单,简明film胶片,薄膜take over接管,接任ruggedness结实threshold界限,临界值with the aid of借助于,用,通过wire 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微波反射技术的英文表达Title: Microwave Reflection Technology: Bridging the Gap Between Theory and ApplicationMicrowave reflection technology, a cornerstone in the field of electromagnetic engineering, plays a pivotal role in modern communication systems and radar technology. This essay delves into the core principles of microwave reflection, its diverse applications, and the challenges it presents to researchers and engineers.At the heart of microwave reflection technology lies the concept of electromagnetic wave reflection. When microwaves encounter a surface, a portion of the energy is reflected back, while the rest is absorbed or transmitted. The behavior of these reflected waves is governed by the laws of physics, particularly the Fresnel equations, which describe the reflection and transmission coefficients at the interface between two media.The reflection coefficient, denoted by Γ, is a complex number that quantifies how much of the incident wave is reflected. It depends on the properties of the media, such as the dielectric constant and conductivity, as well as the angle ofincidence and the polarization of the wave. Understanding and manipulating these variables is crucial for optimizing the performance of microwave systems.The applications of microwave reflection technology span various domains, each leveraging its unique properties to solve complex problems.Radar Technology: Radar systems, which rely on microwave reflection for object detection, have been revolutionized by the ability to analyze reflected signals. By measuring the phase and amplitude of the reflected signals, radar can accurately determine the position, velocity, and even the shape of distant objects, making it indispensable in military, meteorological, and civilian navigation applications Microwave Imaging: In medical diagnostics, microwave reflection is used in imaging technologies such as microwave tomography and radar imaging. These systems can detect anomalies in the human body by analyzing the reflected microwave signals, offering a non-invasive alternative toX-rays.Quality Control in Manufacturing: In industries that require non-destructive testing, microwave reflection is used to inspect materials for defects and ensure quality. Thetechnology can detect changes in the material's properties, such as moisture content and density, without causing damage.Despite its widespread applications, microwave reflection technology faces significant challenges that hinder its full potential. These include the complexity of designing systems that can efficiently manipulate microwave signals, the need for accurate models to predict wave behavior in complex environments, and the integration of microwave technology into emerging fields such as 5G communications and quantum computing.Future advancements in microwave reflection technology will likely focus on miniaturization, integration with other technologies, and the development of intelligent systems capable of dynamic adaptation to changing conditions. Research into new materials and manufacturing techniques will also play a critical role in overcoming current limitations and expanding the capabilities of microwave systems.In conclusion, microwave reflection technology, with its foundational principles and broad applications, is a vital area of research and development. As we continue to push the boundaries of what is possible, the future of microwavereflection technology promises to be as exciting as it is transformative.。
Keysight N9038AMXE EMI Receiver–3 Hz up to 44 GHz frequency range–Compliant with CISPR 16-1-1:2010 and MIL-STD-461–± 0.5 dB at 1 GHz amplitude accuracySummary of Key SpecificationsThe X-Series difference Future-readyOptimize your investment and extend instrument longevity with upgradeable processor, memory, connectivity, and more to keep your test assets current today and tomorrow.Consistent measurement frameworkAchieve measurement integrity across your organization and drive more productivity in less time by leveraging a proven foundation for signal analysis and identical operation across the X-Series instruments.Broadest set of applicationsAddress the changing demands of technology with additionalmeasurement applications, the ability to run software inside the openWindows operating system, and a first-to-market track record in emerging standards.Stay ready, stay in sync, and arrive ahead —with the Keysight X-Series./find/X-SeriesKeep the Test Queue FlowingIn EMC testing, success depends on tools that can help you do more in less time—today and tomorrow. That’s why we created the MXE: it’s a standards-compliant EMI receiver and diagnostic signal analyzer built on an upgradeable platform. In the lab and on the bench, it provides the accuracy, repeatability,and reliability you need to test with confidence.The MXE makes it easy to test in accordance with CISPR 16-1-1:2010 and MIL-STD-461. Choose the frequency coverage you need—up to 3.6, 8.4, 26.5, or44 GHz—and fully test devices with outstanding accuracy and excellent sensitivity across the required ranges.Through the front panel or remotely with software, you can evaluate emissions and identify suspect signals using EMC measurements and a variety of intuitive displays. The extensive set of built-in analysis tools helps you diagnose the causes of noncompliant emissions.With all these capabilities and more, the MXE enables you and your team to keep the test queue flowing.Extend instrument longevity with easy upgradabilityTo keep your instrument current and extend its longevity, the MXE offers easy upgradability of hardware and software capabilities. For example, you can enhance platform performance through CPU and memory upgrades, and add functionality with a simple license key.Leverage the proven reliability of a mature hardware platform Uptime is essential in a test lab and that’s why we built the MXE on the robust Keysight X-Series signal analyzer platform. In addition, the MXE carries the benefits of Keysight’s standard three-year warranty and responsive service and support team.The MXE is ideally suited for high-performance EMC testing in commercial and military applications. The instrument offers a range of CISPR- and MIL-STD-compliant capabilities—detectors, bandwidths, and more—as well as features that further enhance the accuracy and throughput of EMC testing and data analysis.Simplify setupThe MXE contains a number of features that simplify the setup process for compliance measurements. For example, you can use setup tables to create specific measurement configurations for a variety of frequency ranges and antennas. You can also reduce overall setup time by saving and recallingfrequently used custom instrument settings. In addition, the MXE can remotely control switching functions in external LISNs.To accelerate identification of suspect emissions, access the built-in library of limit lines and activate the relevant regulatory limits. You can also define custom limit lines with the easy-to-use editor. To ensure appropriate limit testing, the MXE can automatically correct measured amplitudes for specific transducers, antennas, cabling, and external preamplifiers using customer-configured amplitude correction files.Accelerate data collectionThe MXE is designed to help you see signal activity—quickly and easily—from multiple perspectives. The comprehensive user display allows you to see both a broad overview of the emissions environment and a detailed view of the signal amplitude at a single frequency.Easily capture emissions data using built-in automated scan, search, and measure functions that mirror recommended commercial and military testing procedures. The multi-trace and max hold capabilities let you view emissions from the current position of the device under test (DUT) along with themaximum emissions from all DUT positions. During monitoring, the three color-coded detectors are updated simultaneously to ensure accurate results.The MXE receiver display provides a simplified view into the emissions performance of the DUT.Maximize Throughput in Compliance TestingChoose from traditional frequency or rapid time domain scanning.Easily identify suspect signalsWith built-in measurement and analysis functions, the MXE makes it easy to identify suspect emissions. For example, the unique color-coded trace display capability clearly identifies signals that exceed the selected limit lines and margins.When creating suspect lists, you can choose between traditional frequency scanning and rapid time domain scanning. Time domain scans significantly reduce the time needed to create a list of suspect emissions prior to making final measurements.Built-in limit testing makes it easy to create emission suspect lists. The receiver can automatically move out-of-limit signals to the signal list, where you can perform measurements with the touch of a button.Simplify final measurementsThe list function in the MXE makes it easy to perform final emissionsmeasurements for all supported standards. When you need to control tower or turntable position, internal frequency lists can be passed to automationsoftware. When orientation optimization isn’t required, built-in capabilities help you complete final measurements with ease.When final measurements are complete, you can conveniently create reports in HTML or PDF format with customized content that includes amplitude corrections, limits, scan tables, trace data, signal lists, and screen shots.All-digital IF architectureA digital intermediate frequency (IF) receiver architecture improvesmeasurement accuracy. By comparison, an analog IF architecture implements gain blocks, log amps, resolution bandwidths, and detectors with analog hardware. Even the best of these designs exhibit performance differences when receiver settings are changed from the settings used for calibration. These differences are then exacerbated over temperature.The all-digital IF architectureincludes digital realizations of the key components, which operate on the signal after it has been digitized. Digital IF can improve EMC measurement throughput by minimizing the need for users to bring the signal being measured to the top of the reference level. Analog receivers require this step for every measurement to minimize the effects of analog hardware errors.In addition, digital IF architecturereduces the occurrence of IF overload, even if signals are above the reference level.As an EMI receiver and diagnostic signal analyzer, the MXE puts a wealth of capabilities at yourfingertips. New receiver technology reduces measurement time and ensures you are prepared for future requirements.Go faster with time domain scanningThe MXE offers three types offrequency scanning: swept, stepped, and time domain. Time domain scan decreases total test time by reducing overall prescan collection times when longer measurement dwell times are required.Time domain scan speedsmeasurements by using high-overlap fast Fourier transforms (FFTs) tocollect emissions data simultaneously over an acquisition bandwidth that is multiple resolution bandwidths wide. This is in contrast to frequency-domain measurements, whichcollect data in individual resolution bandwidths.With time domain testing, you can collect suspect lists rapidly, greatly improving overall test time and throughput.Automate click measurementsUse the MXE's built-in disturbance analyzer to easily make discontinuous disturbance, or click, measurements as specified in CISPR 14-1. Simplify and automate data collection, analysis, and report generation for these commonly tested emissions for more efficient testing.Enhance Your Lab with the Latest CapabilitiesComparison of resolution and FFT acquisition bandwidths.FrequencyA m p l i t u d eFFT acquisition bandwidthA m p l i t u d eFrequencyReceiver resolution bandwidthSwept or stepped frequency domain scanTime domain scanDwell for each resolution bandwidthDwell for each FFT bandwidth (multiple resolution bandwidth)Simplify and automate data collection, analysis, and report generation for click measurements.Be ready for APD measurementsThe MXE helps future-proof your lab by offering the amplitude probability distribution (APD) function that is being considered by CISPR foremissions testing of microwave ovens. To characterize slowly-varyingemissions, the APD function displays the probability of an emissionreaching or exceeding a given level. To facilitate use of this new function, the MXE also offers specific limit-line types that can be used with built-in evaluation capabilities to simplify DUT testing.Find the maximum with monitor spectrumIn EMC testing, capturing the maximum value of each emissionfrequency is crucial. Doing so enables accurate characterization of the DUT.To ensure that you have identified the frequencies of maximum emissions in your suspect list, the MXE offers a new feature called monitor spectrum. This feature offers both live-spectrum and meter displays that make it easy to see emission levels and find the maximum while adjusting the center frequency. Ultimately, monitor spectrum improves overall measurement time by reducing the time it takes to prepare your signal list for final measurements.Monitor spectrum identifies frequency of peak emissions.Be ready for future applications with the APD function.The global center frequency feature lets you easily track signals in both the receiver and spectrum analyzer.Gain Insight with Extensive Diagnostic CapabilitiesVerifying product compliance is just one facet of EMI testing. Solving emissions problems can present a wide range of challenges, and the MXE offers a number of tools that will help you see and understand what’s happening.Leverage powerful spectrum analysisInvestigate out-of-compliance emissions with the MXE’s built-in X-Series spectrum analysis capabilities, which include a rich set of resolution and video analysis bandwidths, detectors, and marker functions. In addition, the MXE includes the X-Series PowerSuite measurements for characterization of transmitted signals.Switching between receiver and spectrum analyzer modes is greatlysimplified with the global center frequency function, which links the viewed frequencies. When analyzing an emission, any modification of its frequency will be automatically updated in the MXE’s suspect list, simplifying the final measurement process.Enhance precompliance measurementsYou can leverage the power and usability of the MXE when making precompliance measurements. The Keysight EMI measurement applications (N6141A and W6141A) put the functionality of the MXE inside any of our X-Series signalanalyzers: PXA, MXA, EXA, or CXA. The excellent sensitivity of the X-Series signal analyzers translates into highly accurate emissions measurements.For PXA, MXA or EXA:/find/N6141A For CXA:/find/W6141AStrip Chart mode provides a unique, gap-free view that is useful fortracking DUT performance as a function of turntable or antenna position.Spectrogram displays and the signal-marker capability help you understand the amplitude–and time-varying nature of emissions.RTSA lets you see and understand high-speed transient signals that aredifficult to capture.See amplitude variation vs time with Strip ChartCharacterize the variation of signal amplitude versus time using Strip Chart, a Keysight-exclusive feature which plots data for up to three detectors. All collected data isgapless, with a two-hour time record. This feature is especially useful for capturing the azimuthal emissions characteristics of a DUT when testing on a turntable.The frequency used for the Strip Chart display is coupled to the suspect list, making it easy to view each signal in the suspect list.View varying emissions with spectrograph displaysObserve how emissions spanning a broad spectral range change over time using the built-in spectrograph display. Tracking any variations in spectral data can provide clues about the origins of out-of-compliance emissions.Capture transient signals with real-time spectrum analysisDiagnose high-speed transient signals using real-time spectrum analysis (RTSA) with frequencymask trigger capability. Preselected microwave RTSA enables image-free, over-the-air signal analysis so you can more quickly and easily analyze sources of radiated emissions.Build a Complete EMI Test SolutionProtect Your Investment with an Upgradable PlatformOur qualified Keysight Solution Partners provide a single point of contact to purchase complete EMI measurement solutions that meet commercial and military specifications. In addition to the MXE EMI receiver, they can provide equipment including chambers, probes, towers and antennas, and services such as integration, installation, training, and support. To further simplify testing, they also offer automation software that can meet your specific needs.If you need to go beyond emission and immunity, our solution partners can provide ESD, line harmonics, droop testing, and more.To keep your instrument current and extend its longevity, the MXE offers easy upgradability of hardware and software. When needed, you can enhanceplatform performance through upgradable CPU, memory, disk drives, and I/O ports. Internally, the mechanical assembly has three expansion slots that can accommodate future enhancements.On the software side, simple license-key upgrades are all it takes to add functionality or measurement applications. For example, the external source control option lets the MXE interface with a variety of Keysight signalgenerators, enabling stimulus/response testing up to 20 GHz. For detailed signal analysis, the library of available measurement applications includes analog demodulation, phase noise, and noise figure.Upgrade frequencyThrough return-to-Keysight upgrades, you can extend the frequency range of MXE EMI receivers up to 44 GHz. The receiver maintains its options, applications, and serial number.While the receiver is at the service center for a frequency extension, it is a convenient time to add functionality such as time domain scan for fast FFT-based frequency scanning.For precompliance testing, Keysight also offers frequency upgrades on PXA, MXA, or EXA signal /find/frequencyup11 | Keysight | MXE EMI Receiver N9038A - BrochureMXE Front and Rear PanelsView up to threedifferent prehensive display provides view of spectrum, meters, and suspect list.Second inputpulse-protected to 2 kW.Removable CPU enables processor, memory, and I/O upgrades.Auxiliary/IO port for LISN control.Send and receive SCPI commands over the GPIB interface.Identify signals and view information easily on the 21.4-cm, high-resolution XGA display.Acquire IQ waveform data quickly or control the MXE remotely from an external PC over the USB 2.0 (type-B port) interface.Synchronize other test equipment with the analyzer using the external trigger output signals.Get answers quickly with the comprehensive, context-sensitive embedded help system.Connect external peripherals and transfer data via the USB 2.0 (type-A port) interface.Navigate the interface and help system using the front-panel keys, or a mouse and keyboard.Test devices up to 44 GHz.View the display on an external monitor by connecting to the VGA video output.Two USB 2.0 ports conveniently located on the front of the instrument.Control the MXE remotely over1000Base-T LAN.Removable solid-state drive.Additional solid-state driveavailable for instrument security.Save files fast with the quick-save feature.12 | Keysight | MXE EMI Receiver N9038A - BrochureThis information is subject to change without notice.© Keysight Technologies, 2013 - 2018Published in USA, March 27, 20185990-7422ENRelated LiteratureKeysight MXE EMI receiverPublication title Publication number Data Sheet5990-7421EN Configuration Guide5990-7419EN X-Series Measurement Application Brochure5989-8019EN/find/mxeEvolving Since 1939Our unique combination of hardware, software, services, and people can help you reach your next breakthrough. 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英语科技文选试题课程代码:00836PART A: VOCABULARYI. Directions: Add the affix to each word according to the given Chinese, makingchanges when necessary. (8 %)1.accelerate 加速装置 1._________________2.contrast 对比的 2._________________3.alternance 可选择的 3._________________pass 包含 4._________________pare 可比的 5._________________6.bewilder 迷惑不解(名词) 6._________________7.attractive 诱引剂7._________________8.different 区分8._________________II. Directions:Fill in the blanks,each using one of the given words or phrases below in its prope form.(12%)stem from in addition at randompile of in contrast bump intoin the event of in all probability bear outwithin reach of/one’s reach be associated with take one’s place9.I_______________ an old friend of mine at the gas station.10.The new work of his will_______________ among the most important paintings of this century.11.Dependence on alcohol often________________ unhappiness in the home.12.He asked his sister to look after his children________________ his death.13.I’ve no idea where last Saturday’s newspaper is;_______________,it might have been thrown away.14.The facts don’t______________your fears.15.Isabelle placed a wine cup on the table__________________.16.The first thing the secretary does is to sort out the_______________ documents and letters on his desk.17.The lottery numbers are chosen_______________.18.His bad behavior__________________ his difficult childhood.19.It is hot in the day time,but________________it’s very cold at night.20.I need your help.________________ ,I need her support.Ⅲ.Directions:Fill in each blank with a suitable word given below.(10%)massive likely whether Galaxy long hits from off was MilkyThe cloud, called Smith’s Cloud,after the astronomer who discovered it in 1963,contains enough hydrogen to make a million stars like the Sun. Eleven thousand light-years _21_ and 2,500light-years wide,it is only 8,000 light-years_22_our Galaxy’s disk. It is rushing toward our _23_ at more than 150 miles per second,aimed to strike the Milky Way’s disk at an angle of about 45degrees."This is most _24_ a gas cloud left over from the formation of the Milky Way or gas stripped froma neighbor galaxy. When it _25_,it could set off a tremendous burst of star formation. Many of those stars will be very _26_. Over a few million years,it'll look like a celestial New Year’s celebration,with huge firecrackers going _27_in that region of the Galaxy," Lockman said. When Smith’s Cloud _28_ first discovered,and for decades after, the available images did not have enough detail to show _29_ the cloud was part of the Milky Way,somethingbeing blown out of the _30_ Way,or something falling in.PART B:TRANSLATIONⅣ. Directions:Translate the following sentences into English,each using one of the given words or phrases below. (10%)attribute customary subject reminiscent of come into its own31.你的讲述让我想起十年前的一次经历。
我研究微波遥感的英语作文Title: Exploring Microwave Remote Sensing。
Microwave remote sensing is a crucial tool in contemporary scientific research, offering a unique perspective on various aspects of the Earth's surface and atmosphere. In this essay, we will delve into the principles, applications, and advancements in microwave remote sensing.Firstly, it's essential to understand the underlying principles of microwave remote sensing. Microwave radiation, with wavelengths ranging from about one millimeter to one meter, interacts differently with different materials. This interaction provides valuable information about the properties of the target being observed. Unlike visiblelight or infrared radiation, microwave radiation can penetrate clouds, vegetation, and soil, allowing for observations regardless of weather conditions or time of day.Microwave remote sensing finds extensive applications in various fields such as meteorology, agriculture, hydrology, and environmental monitoring. One of its primary applications is in weather forecasting, where microwave sensors onboard satellites provide data on atmospheric temperature, humidity, and cloud cover. This information is crucial for predicting weather patterns and severe weather events.In agriculture, microwave remote sensing helps monitor soil moisture levels, crop growth, and detect anomalies such as drought stress or pest infestations. By analyzing microwave signals reflected or emitted from the Earth's surface, scientists can assess soil moisture content with high precision, aiding in irrigation management and crop yield optimization.Moreover, microwave sensors play a vital role in monitoring Earth's water resources. By measuring microwave radiation emitted by water bodies, scientists can estimate parameters like sea surface temperature, sea ice extent,and ocean salinity. This data is essential for understanding climate dynamics, ocean circulation patterns, and assessing the impact of climate change on marine ecosystems.Furthermore, microwave remote sensing is instrumental in studying Earth's cryosphere, including polar ice caps, glaciers, and permafrost. Microwave sensors onboard satellites provide valuable data on ice extent, thickness, and melting rates, contributing to our understanding of global sea-level rise and polar climate change.In recent years, significant advancements have been made in microwave remote sensing technology, leading to improved data resolution, accuracy, and coverage. New sensor designs, such as synthetic aperture radar (SAR), enable high-resolution imaging of Earth's surface with unparalleled detail. Additionally, advancements in data processing techniques, including machine learning algorithms, facilitate the extraction of meaningful information from vast amounts of remote sensing data.Looking ahead, the future of microwave remote sensing holds promise for further innovations and applications. Continued advancements in sensor technology, coupled with enhanced data processing capabilities, will enable scientists to address pressing environmental challenges with greater precision and efficiency.In conclusion, microwave remote sensing is a powerful tool for studying Earth's surface and atmosphere, offering valuable insights into various environmental processes and phenomena. From weather forecasting to agricultural monitoring and climate change research, microwave remote sensing plays a vital role in advancing our understanding of the planet's dynamic systems. With ongoing technological advancements, the potential for further discoveries and applications in this field is vast.。
一、常考典型错误1、一致性方面的错误1)主谓一致主谓不一致错误是综合改错题内容之一,主要表现为主语名词与谓语动词间隔较长,首尾不能相接,造成视觉上的混淆。
1. The president of the company,together with the workers, are planning a conference for the purpose of solving financial problems.2. In early January 1976 the Netherlands were hit by its worst storm since 1953.3. Ham and egg are a good breakfast.4. The professor and writer are very excited.5. The manager with some workers were working during the holidays.6. Five hours are needed to complete the outline.7. Many a man have done his duty.8. More than one game were lost.2)名词单复数有时名词可以不用复数,但是在特定的句子中由于前面有明确的量词修饰,如many,several, a number of, a variety of等等,就要变成复数形式。
1. Computer,as we all know,has many possible use in different fields.2. The letter contained an important information.3. He is relating to the children his experience as explorer.3)代词与先行词一致代词的主要功能是指代已出现的名词、词组或一个意群,因此代词的出现必须有所指,而且形、数等必须与前面所代的部份相符。
transistor n 晶体管diode n 二极管semiconductor n 半导体resistor n 电阻器capacitor n 电容器alternating adj 交互的amplifier n 扩音器,放大器integrated circuit 集成电路linear time invariant systems 线性时不变系统voltage n 电压,伏特数Condenser=capacitor n 电容器dielectric n 绝缘体;电解质electromagnetic adj 电磁的adj 非传导性的deflection n偏斜;偏转;偏差linear device 线性器件the insulation resistance 绝缘电阻anode n 阳极,正极cathode n 阴极breakdown n 故障;崩溃terminal n 终点站;终端,接线端emitter n 发射器collect v 收集,集聚,集中insulator n 绝缘体,绝热器oscilloscope n 示波镜;示波器gain n 增益,放大倍数forward biased 正向偏置reverse biased 反向偏置P-N junction PN结MOS(metal-oxide semiconductor)金属氧化物半导体enhancement and exhausted 增强型和耗尽型integrated circuits 集成电路analog n 模拟digital adj 数字的,数位的horizontal adj, 水平的,地平线的vertical adj 垂直的,顶点的amplitude n 振幅,广阔,丰富multimeter n 万用表frequency n 频率,周率the cathode-ray tube 阴极射线管dual-trace oscilloscope 双踪示波器signal generating device 信号发生器peak-to-peak output voltage 输出电压峰峰值sine wave 正弦波triangle wave 三角波square wave 方波amplifier 放大器,扩音器oscillator n 振荡器feedback n 反馈,回应phase n 相,阶段,状态filter n 滤波器,过滤器rectifier n整流器;纠正者band-stop filter 带阻滤波器band-pass filter 带通滤波器decimal adj 十进制的,小数的hexadecimal adj/n十六进制的binary adj 二进制的;二元的octal adj 八进制的domain n 域;领域code n代码,密码,编码v编码the Fourier transform 傅里叶变换Fast Fourier Transform 快速傅里叶变换microcontroller n 微处理器;微控制器assembly language instrucions n 汇编语言指令chip n 芯片,碎片modular adj 模块化的;模数的sensor n 传感器plug vt堵,塞,插上n塞子,插头,插销coaxial adj 同轴的,共轴的fiber n 光纤relay contact 继电接触器Artificial Intelligence 人工智能Perceptive Systems 感知系统neural network 神经网络fuzzy logic 模糊逻辑intelligent agent 智能代理electromagnetic adj 电磁的coaxial adj 同轴的,共轴的microwave n 微波charge v充电,使充电insulator n 绝缘体,绝缘物nonconductive adj非导体的,绝缘的simulation n 仿真;模拟prototype n 原型array n 排队,编队vector n 向量,矢量inverse adj倒转的,反转的n反面;相反v倒转high-performance 高精确性,高性能two-dimensional 二维的;缺乏深度的three-dimensional 三维的;立体的;真实的object-oriented programming面向对象的程序设计spectral adj 光谱的distortion n 失真,扭曲,变形wavelength n 波长refractive adj 折射的ivision Multiplexing单工传输simplex transmission半双工传输half-duplex transmission全双工传输full-duplex transmission电路交换circuit switching数字传输技术Digital transmission technology灰度图像Grey scale images灰度级Grey scale level幅度谱Magnitude spectrum相位谱Phase spectrum频谱frequency spectrum相干解调coherent demodulation coherent相干的数字图像压缩digital image compression图像编码image encoding量化quantization人机交互man machine interface交互式会话Conversational interaction路由算法Routing Algorithm目标识别Object recognition话音变换Voice transform中继线trunk line传输时延transmission delay远程监控remote monitoring光链路optical linkhalf-duplex transmission 半双工传输accompaniment 伴随物,附属物reservation 保留,预定quotation 报价单,行情报告,引语memorandum 备忘录redundancy 备用be viewed as 被看作…be regards as 被认为是as such 本身;照此;以这种资格textual 本文的,正文的variation 变化,变量conversion 变化,转化identity 标识;标志criterion 标准,准则in parallel on 并联到,合并到juxtapose 并置,并列dialing pulse 拨号脉冲wave-guide 波导wavelength division multiplexed 波分复用baud rate 波特率playback 播放(录音带,唱片)no greater than 不大于update 不断改进,使…适合新的要求,更新asymmetric 不对称的irrespective 不考虑的,不顾的inevitably 不可避免的inevitable 不可避免的,不可逃避的,必定的segment 部分abrasion 擦伤,磨损deploy 采用,利用,推广应用take the form of 采用…的形式parameter 参数,参量layer 层dope 掺杂FET(field effect transistors) 场效应管audio recording 唱片ultra-high-frequency(UHF) 超高频in excess of 超过in excess of 超过hypertext 超文本ingredient 成分,因素ingredient 成分,组成部分,要素metropolitan-area network(WAN) 城域网metropolitan area network(WAN) 城域网,城市网络congestion 充满,拥挤,阻塞collision 冲突extractive 抽出;释放出extract 抽取,取出,分离lease 出租,租约,租界期限,租界物pass on 传递,切换transmission 传输facsimile 传真innovative=innovatory 创新的,富有革新精神的track 磁道impetus 促进,激励cluster 簇stored-program control(SPC) 存储程序控制a large number of 大量的peal 大声响,发出supersede 代替supplant 代替,取代out-of-band signaling 带外信号simplex transmission 单工传输monochromatic 单色的,单色光的,黑白的ballistic 弹道的,射击的,冲击的conductor 导体hierarchy 等级制度,层次infrastructure 底层结构,基础结构geographic 地理的,地区的geographically 地理上GIS(ground instrumentation system) 地面测量系统ground station 地面站earth orbit 地球轨道extraterrestrial 地球外的,地球大气圈外的Land-sat 地球资源卫星rug 地毯,毯子ignite 点火,点燃,使兴奋electromagnetic 电磁的inductive 电感arc 电弧telephony 电话(学),通话dielectric 电介质,绝缘材料;电解质的,绝缘的capacitor 电容telecommunication 电信,无线电通讯scenario 电影剧本,方案modem pool 调制解调器(存储)池superimposing 叠加,重叠pin 钉住,扣住,抓住customize 定做,定制monolithic 独立的,完全统一的aluminize 镀铝strategic 对全局有重要意义的,战略的substantial 多的,大的,实际上的multi-path fading 多径衰落multi-path 多路,多途径;多路的,多途径的multi-access 多路存取,多路进入multiplex 多路复用multiplex 多路复用的degradation 恶化,降级dioxide 二氧化碳LED(light-emitting-diode) 发光二极管evolution 发展,展开,渐进feedback 反馈,回授dimension 范围,方向,维,元scenario 方案scenario 方案,电影剧本amplifer 放大器noninvasive 非侵略的,非侵害的tariff 费率,关税率;对…征税distributed functional plane(DFP) 分布功能平面DQDB(distributed queue dual bus) 分布式队列双总线hierarchy 分层,层次partition 分成segmentation 分割interface 分界面,接口asunder 分开地,分离地detached 分离的,分开的,孤立的dispense 分配allocate 分配,配给;配给物centigrade 分为百度的,百分度的,摄氏温度的fractal 分形molecule 分子,微小,些微cellular 蜂窝状的cellular 蜂窝状的,格形的,多孔的auxiliary storage(also called secondary storage)辅助存储器decay 腐烂,衰减,衰退negative 负电vicinity 附近,邻近vicinity 附近地区,近处sophisticated 复杂的,高级的,现代化的high-frequency(HF) 高频high definition television 高清晰度电视chromium 铬annotate 给…作注解in terms of 根据,按照disclosure 公布,企业决算公开public network 公用网functionality 功能,功能度mercury 汞resonator 共鸣器resonance 共振whimsical 古怪的,反复无常的administration 管理,经营cursor 光标(显示器),游标,指针optical computer 光计算机photoconductor 光敏电阻optical disks 光盘optically 光学地,光地wide-area networks 广域网specification 规范,说明书silicon 硅the international telecommunication union(ITU)国际电信联盟excess 过剩obsolete 过时的,废弃的maritime 海事的synthetic 合成的,人造的,综合的synthetic 合成的,综合性的rational 合乎理性的rationalization 合理化streamline 合理化,理顺infrared 红外线的,红外线skepticism 怀疑论ring network 环形网hybrid 混合物counterpart 伙伴,副本,对应物electromechanical 机电的,电动机械的Robot 机器人Robotics 机器人技术,机器人学accumulation 积累infrastructure 基础,基础结构substrate 基质,底质upheaval 激变,剧变compact disc 激光磁盘(CD)concentrator 集中器,集线器centrex system 集中式用户交换功能系统converge on 集中于,聚集在…上lumped element 集总元件CAI(computer-aided instruction) 计算机辅助教学computer-integrated manufacturing(CIM) 计算机集成制造computer mediated communication(CMC) 计算机中介通信record 记录register 记录器,寄存器expedite 加快,促进weight 加权accelerate 加速,加快,促进categorize 加以类别,分类in addition 加之,又,另外hypothetical 假设的rigidly 坚硬的,僵硬的compatibility 兼容性,相容性surveillance 监视surveillance 监视retrieval 检索,(可)补救verification 检验simplicity 简单,简明film 胶片,薄膜take over 接管,接任ruggedness 结实threshold 界限,临界值with the aid of 借助于,用,通过wire line 金属线路,有线线路coherent 紧凑的,表达清楚的,粘附的,相干的compact 紧密的approximation 近似undertake 进行,从事transistor 晶体管elaborate 精心制作的,细心完成的,周密安排的vigilant 警戒的,警惕的alcohol 酒精,酒local area networks(LANs) 局域网local-area networks(LANs) 局域网drama 剧本,戏剧,戏剧的演出focus on 聚集在,集中于,注视insulator 绝缘root mean square 均方根uniform 均匀的open-system-interconnection(OSI) 开放系统互连expire 开始无效,满期,终止immunity 抗扰,免除,免疫性take…into account 考虑,重视…programmable industrial automation 可编程工业自动化demountable 可拆卸的tunable 可调的reliable 可靠be likely to 可能,大约,像要videotex video 可视图文电视negligible 可以忽略的aerial 空气的,空中的,无形的,虚幻的;天线broadband 宽(频)带pervasive 扩大的,渗透的tensile 拉力的,张力的romanticism 浪漫精神,浪漫主义discrete 离散,不连续ion 离子force 力量;力stereophonic 立体声的continuum 连续统一体,连续统,闭联集smart 灵巧的;精明的;洒脱的token 令牌on the other hand 另一方面hexagonal 六边形的,六角形的hexagon 六角形,六边形monopoly 垄断,专利video-clip 录像剪辑aluminum 铝pebble 卵石,水晶透镜forum 论坛,讨论会logical relationships 逻辑关系code book 码本pulse code modulation(PCM) 脉冲编码调制roam 漫步,漫游bps(bits per second) 每秒钟传输的比特ZIP codes 美国邮区划分的五位编码susceptible(to) 敏感的,易受…的analog 模拟,模拟量pattern recognition模式识别bibliographic 目录的,文献的neodymium 钕the european telecommunicationstandardization institute(ETSI) 欧洲电信标准局coordinate 配合的,协调的;使配合,调整ratify 批准,认可bias 偏差;偏置deviate 偏离,与…不同spectrum 频谱come into play 其作用entrepreneurial 企业的heuristic methods 启发式方法play a …role(part) 起…作用stem from 起源于;由…发生organic 器官的,有机的,组织的hypothesis 前提front-end 前置,前级potential 潜势的,潜力的intensity 强度coincidence 巧合,吻合,一致scalpel 轻便小刀,解剖刀inventory 清单,报表spherical 球的,球形的distinguish 区别,辨别succumb 屈服,屈从,死global functional plane(GFP) 全局功能平面full-duplex transmission 全双工传输hologram 全息照相,全息图deficiency 缺乏thermonuclear 热核的artifact 人工制品AI(artificial intelligence) 人工智能fusion 熔解,熔化diskettes(also called floppy disk) 软盘sector 扇区entropy 熵uplink 上行链路arsenic 砷neural network 神经网络very-high-frequency(VHF) 甚高频upgrade 升级distortion 失真,畸变identification 识别,鉴定,验明pragmatic 实际的implementation 实施,实现,执行,敷设entity 实体,存在vector quantification 矢量量化mislead 使…误解,给…错误印象,引错vex 使烦恼,使恼火defy 使落空facilitate 使容易,促进retina 视网膜compatible 适合的,兼容的transceiver 收发两用机authorize 授权,委托,允许data security 数据安全性data independence 数据独立data management 数据管理database 数据库database management system(DBMS) 数据库管理信息系统database transaction 数据库事务data integrity 数据完整性,数据一致性attenuation 衰减fading 衰落,衰减,消失dual 双的,二重的transient 瞬时的deterministic 宿命的,确定的algorithm 算法dissipation 损耗carbon 碳diabetes 糖尿病cumbersome 讨厌的,麻烦的,笨重的razor 剃刀,剃go by the name of 通称,普通叫做commucation session 通信会话traffic 通信业务(量)synchronous transmission 同步传输concurrent 同时发生的,共存的simultaneous 同时发生的,同时做的simultaneous 同时发生的,一齐的coaxial 同轴的copper 铜statistical 统计的,统计学的dominate 统治,支配invest in 投资perspective 透视,角度,远景graphics 图示,图解pictorial 图像的coating 涂层,层deduce 推理reasoning strategies 推理策略inference engine 推理机topology 拓扑结构heterodyne 外差法的peripheral 外界的,外部的,周围的gateway 网关hazardous 危险的microwave 微波(的)microprocessor 微处理机,微处理器microelectronic 微电子nuance 微小的差别(色彩等)encompass 围绕,包围,造成,设法做到maintenance 维护;保持;维修satellite communication 卫星通信satellite network 卫星网络transceiver 无线电收发信机radio-relay transmission 无线电中继传输without any doubt 无疑passive satellite 无源卫星sparse 稀少的,稀疏的downlink 下行链路precursor 先驱,前任visualization 显像feasibility 现实性,可行性linearity 线性度constrain 限制,约束,制约considerable 相当的,重要的geo-stationary 相对地面静止by contrast 相反,而,对比起来coorelation 相关性mutual 相互的mutually 相互的,共同的interconnect 相互连接,互连one after the other 相继,依次minicomputer 小型计算机protocol 协议,草案protocol 协议,规约,规程psycho-acoustic 心理(精神)听觉的;传音的channelization 信道化,通信信道选择run length encoding 行程编码groom 修饰,准备virtual ISDN 虚拟ISDNmultitude 许多,大批,大量whirl 旋转preference 选择,喜欢avalanche 雪崩pursue 寻求,从事interrogation 询问dumb 哑的,不说话的,无声的subcategory 亚类,子种类,子范畴orbital 眼眶;轨道oxygen 氧气,氧元素service switching and control points(SSCPs) 业务交换控制点service control points(SCPs) 业务控制点service control function(SCF) 业务控制功能in concert 一致,一齐handover 移交,越区切换at a rate of 以……的速率in the form of 以…的形式base on…以…为基础yttrium 钇(稀有金属,符号Y)asynchronous transmission 异步传输asynchronous 异步的exceptional 异常的,特殊的voice-grade 音频级indium 铟give rise to 引起,使产生cryptic 隐义的,秘密的hard disk 硬盘hard automation 硬自动化by means of 用,依靠equip with 用…装备subscriber 用户telex 用户电报PBX(private branch exchange) 用户小交换机或专用交换机be called upon to 用来…,(被)要求…superiority 优势predominance 优势,显著active satellite 有源卫星in comparison with 与…比较comparable to 与…可比preliminary 预备的,初步的premonition 预感,预兆nucleus 原子核valence 原子价circumference 圆周,周围teleprocessing 远程信息处理,遥控处理perspective 远景,前途constrain 约束,强迫mobile 运动的,流动的,机动的,装在车上的convey 运输,传递,转换impurity 杂质impurity 杂质,混杂物,不洁,不纯regenerative 再生的improve over 在……基础上改善play important role in 在…中起重要作用in close proximity 在附近,在很近underlying 在下的,基础的in this respect 在这方面germanium 锗positive 正电quadrature 正交orthogonal 正交的quadrature amplitude modulation(QAM) 正交幅度调制on the right track 正在轨道上sustain 支撑,撑住,维持,持续outgrowh 支派;长出;副产品dominate 支配,统治knowledge representation 知识表示knowledge engineering 知识工程knowledge base 知识库in diameter 直径helicopter 直升飞机acronym 只取首字母的缩写词as long as 只要,如果tutorial 指导教师的,指导的coin 制造(新字符),杜撰fabrication 制造,装配;捏造事实proton 质子intelligence 智能,智力,信息intelligent network 智能网intermediate 中间的nucleus(pl.nuclei) 中心,核心neutrons 中子terminal 终端,终端设备overlay 重叠,覆盖,涂覆highlight 重要的部分,焦点charge 主管,看管;承载dominant 主要的,控制的,最有力的cylinder 柱面expert system 专家系统private network 专用网络transition 转变,转换,跃迁relay 转播relay 转播,中继repeater 转发器,中继器pursue 追赶,追踪,追求,继续desktop publish 桌面出版ultraviolet 紫外线的,紫外的;紫外线辐射field 字段vendor 自动售货机,厂商naturally 自然的;天生具备的synthesize 综合,合成integrate 综合,使完全ISDN(intergrated services digital network) 综合业务数字网as a whole 总体上bus network 总线形网crossbar 纵横,交叉impedance 阻抗initial 最初的,开始的optimum 最佳条件appear as 作为…出现A Analog 模拟A/D Analog to Digital 模-数转换AAC Advanced Audio Coding 高级音频编码ABB Automatic Black Balance 自动黑平衡ABC American Broadcasting Company 美国广播公司Automatic Bass Compensation 自动低音补偿Automatic Brightness Control 自动亮度控制ABL Automatic Black Level 自动黑电平ABLC Automatic Brightness LimiterCircuit 自动亮度限制电路ABU Asian Broadcasting Union 亚洲广播联盟(亚广联ABS American Bureau of Standard 美国标准局AC Access Conditions 接入条件Audio Center 音频中心ACA Adjacent Channel Attenuation 邻频道衰减ACC Automatic Centering Control 自动中心控制Automatic Chroma Control 自动色度(增益ACK Automatic Chroma Killer 自动消色器ACP Additive Colour Process 加色法ACS Access Control System 接入控制系统Advanced Communication Service 高级通信业务Area Communication System 区域通信系统ADC Analog to Digital Converter 模-数转换器Automatic Degaussirng Circuit 自动消磁电路ADL Acoustic Delay Line 声延迟线ADS Audio Distribution System 音频分配系统AE Audio Erasing 音频(声音AEF Automatic Editing Function 自动编辑功能AES Audio Engineering Society 音频工程协会AF Audio Frequency 音频AFA Audio Frequency Amplifier 音频放大器AFC Automatic Frequency Coder 音频编码器Automatic Frequency Control 自动频率控制AFT Automatic Fine Tuning 自动微调Automatic Frequency Track 自动频率跟踪Automatic Frequency Trim 自动额率微调AGC Automatic Gain Control 自动增益控制AI Artificial Intelligence 人工智能ALM Audio-Level Meter 音频电平表AM Amplitude Modulation 调幅AMS Automatic Music Sensor 自动音乐传感装置ANC Automatic Noise Canceller 自动噪声消除器ANT ANTenna 天线AO Analog Output 模拟输出APS Automatic Program Search 自动节目搜索APPS Automatic Program Pause System 自动节目暂停系统APSS Automatic Program Search System 自动节目搜索系统AR Audio Response 音频响应ARC Automatic Remote Control 自动遥控ASCII American Standard Code for Information Interchange 美国信息交换标准AST Automatic Scanning Tracking 自动扫描跟踪ATC Automatic Timing Control 自动定时控制Automatic Tone Correction 自动音频校正ATM Asynchronous Transfer Mode 异步传输模式ATF Automatic Track Finding 自动寻迹ATS Automatic Test System 自动测试系统ATSC Advanced Television Systems Committee (美国高级电视制式委员会)***C Automatic Volume Control 自动音量控制***R Automatic Voltage Regulator 自动稳压器AWB Automatic White Balance 自动白平衡AZC Automatic Zooming Control 自动变焦控制AZS Automatic Zero Setting 自动调零BA Branch Amplifier 分支放大器Buffer Amplifier 缓冲放大器BAC Binary-Analog Conversion 二进制模拟转换BB Black Burst 黑场信号BBC British Broadcasting Corporation 英国广播公司BBI Beijing Broadcasting Institute 北京广播学院BC Binary Code 二进制码Balanced Current 平衡电流Broadcast Control 广播控制BCT Bandwidth Compression Technique带宽压缩技术BDB Bi-directional Data Bus 双向数据总线BER Basic Encoding Rules 基本编码规则Bit Error Rate 比特误码率BF Burst Flag 色同步旗脉冲BFA Bare Fiber Adapter 裸光纤适配器Brillouin Fiber Amplifier 布里渊光纤放大器BGM Background Music 背景音乐BIOS Basic Input/Output System 基本输入输出系统B-ISDN Broadband-ISDN 宽带综合业务数据网BIU Basic Information Unit 基本信息单元Bus Interface Unit 总线接口单元BM Bi-phase Modulation 双相调制BML Business Management Layer 商务管理层BN Backbone Network 主干网BNT Broadband Network Termination 宽带网络终端设备BO Bus Out 总线输出BPG Basic Pulse Generator 基准脉冲发生器BPS Band Pitch Shift 分频段变调节器BSI British Standard Institute 英国标准学会BSS Broadcast Satellite Service 广播卫星业务BT Block Terminal 分线盒、分组终端British Telecom 英国电信BTA Broadband Terminal Adapter 宽带终端适配器Broadcasting Technology Association (日本BTL Balanced Transformer-Less 桥式推挽放大电路BTS Broadcast Technical Standard 广播技术标准BTU Basic Transmission Unit 基本传输单元BVU Broadcasting Video Unit 广播视频型(一种3/4英寸带录像机记录格式BW BandWidth 带宽BWTV Black and White Television 黑白电视CA Conditional Access 条件接收CAC Conditional Access Control 条件接收控制CAL Continuity Accept Limit 连续性接受极限CAS Conditional Access System 条件接收系统Conditional Access Sub-system 条件接收子系统CATV Cable Television 有线电视,电缆电视Community Antenna Television 共用天线电视C*** Constant Angular Velocity 恒角速度CBC Canadian Broadcasting Corporation加拿大广播公司CBS Columbia Broadcasting System (美国哥伦比亚广播公司CC Concentric Cable 同轴电缆CCG Chinese Character Generator 中文字幕发生器CCIR International Radio ConsultativeCommittee 国际无线电咨询委员会CCITT International Telegraph andTelephone ConsultativeCommittee 国际电话电报咨询委员会CCR Central Control Room 中心控制室CCTV China Central Television 中国中央电视台Close-Circuit Television 闭路电视CCS Center Central System 中心控制系统CCU Camera Control Unit 摄像机控制器CCW Counter Clock-Wise 反时针方向CD Compact Disc 激光唱片CDA Current Dumping Amplifier 电流放大器CD-E Compact Disc Erasable 可抹式激光唱片CDFM Compact Disc File Manager 光盘文件管理(程序CDPG Compact-Disc Plus Graphic 带有静止图像的CD唱盘CD-ROM Compact Disc-Read OnlyMemory 只读式紧凑光盘CETV China Educational Television 中国教育电视台CF Color Framing 彩色成帧CGA Color Graphics Adapter 彩色图形(显示卡CI Common Interface 通用接口CGA Color Graphics Adapter 彩色图形(显示卡CI Common Interface 通用接口CIE Chinese Institute of Electronics 中国电子学会CII China Information Infrastructure 中国信息基础设施CIF Common Intermediate Format 通用中间格式CIS Chinese Industrial Standard 中国工业标准CLV Constant Linear Velocity 恒定线速度CM Colour Monitor 彩色监视器CMTS Cable Modem Termination System线缆调制解调器终端系统CNR Carrier-to-Noise Ratio 载噪比CON Console 操纵台Controller 控制器CPB Corporation of Public Broadcasting(美国公共广播公司CPU Central Processing Unit 中央处理单元CRC Cyclic Redundancy Check 循环冗余校验CRCC CRI Cyclic Redundancy Check Code循环冗余校验码CROM China Radio International 中国国际广播电台CRT Control Read Only Memory 控制只读存储器CS Cathode-Ray Tube 阴极射线管CSC Communication Satellite 通信卫星CSS Color Sub-carrier 彩色副载波Center Storage Server 中央存储服务器Content Scrambling System 内容加扰系统CSU Channel Service Unit 信道业务单元CT Color Temperature 色温CTC Cassette Tape Controller 盒式磁带控制器Channel Traffic Control 通道通信量控制Counter Timer Circuit 计数器定时器电路Counter Timer Control 计数器定时器控制CTE Cable Termination Equipment 线缆终端设备Customer Terminal Equipment 用户终端设备CTV Color Television 彩色电视CVD China Video Disc 中国数字视盘CW Carrie Wave 载波DAB Digital Audio Broadcasting 数字音频广播DASH Digital Audio Stationary Head 数字音频静止磁头DAT Digital Audio Tape 数字音频磁带DBMS Data Base Management System 数据库管理系统DBS Direct Broadcast Satellite 直播卫星DCC Digital Compact Cassette 数字小型盒带Dynamic Contrast Control 动态对比度控制DCT Digital Component Technology 数字分量技术Discrete Cosine Transform 离散余弦变换DCTV Digital Color Television 数字彩色电视DD Direct Drive 直接驱动DDC Direct Digital Control 直接数字控制DDE Dynamic Data Exchange 动态数据交换DDM Data Display Monitor 数据显示监视器DES Data Elementary Stream 数据基本码流Data Encryption Standard 美国数据加密标准DF Dispersion Flattened 色散平坦光纤DG Differential Gain 微分增益DI Digital Interface 数字接口DITEC Digital Television Camera 数字电视摄像机DL Delay Line 延时线DLD Dynamic Linear Drive 动态线性驱动DM Delta Modulation 增量调制Digital Modulation 数字调制DMB Digital Multimedia Broadcasting 数字多媒体广播DMC Dynamic Motion Control 动态控制DME Digital Multiple Effect 数字多功能特技DMS Digital Mastering System 数字主系统DN Data Network 数据网络DNG Digital News Gathering 数字新闻采集DNR Digital Noise Reducer 数字式降噪器DOB Data Output Bus 数据输出总线DOCSIS Data Over Cable Service Interface Specifications 有线数据传输业务接口规范DOC Drop Out Compensation 失落补偿DOS Disc Operating System 磁盘操作系统DP Differential Phase 微分相位Data Pulse 数据脉冲DPCM Differential Pulse Code Modulation 差值脉冲编码调制DPL Dolby Pro Logic 杜比定向逻辑DSB Digital Satellite Broadcasting 数字卫星广播DSC Digital Studio Control 数字演播室控制DSD Dolby Surround Digital 杜比数字环绕声DSE Digital Special Effect 数字特技DSK Down-Stream Key 下游键DSP Digital Signal Processing 数字信号处理Digital Sound Processor 数字声音处理器DSS Digital Satellite System 数字卫星系统DT Digital Technique 数字技术Digital Television 数字电视Data Terminal 数据终端Data Transmission 数据传输DTB Digital Terrestrial Broadcasting 数字地面广播DTBC Digital Time-Base Corrector 数字时基校正器DTC Digital Television Camera 数字电视摄像机DTS Digital Theater System 数字影院系统Digital Tuning System 数字调谐系统Digital Television Standard 数字电视标准DVB Digital Video Broadcasting 数字视频广播DVC Digital Video Compression 数字视频压缩DVE Digital Video Effect 数字视频特技DVS Desktop Video Studio 桌上视频演播DVTR Digital Video Tape Recorder 数字磁带录像机EA Extension Amplifier 延长放大器EB Electron Beam 电子束EBS Emergency Broadcasting System 紧急广播系统EBU European Broadcasting Union 欧洲广播联盟EC Error Correction 误差校正ECN Emergency Communications Network应急通信网络ECS European Communication Satellite 欧洲通信卫星EDC Error Detection Code 错误检测码EDE Electronic Data Exchange 电子数据交换EDF Erbium-Doped Fiber 掺饵光纤EDFA Erbium-Doped Fiber Amplifier 掺饵光纤放大器EDL Edit Decision List 编辑点清单EDTV Extended Definition Television 扩展清晰度电视EE Error Excepted 允许误差EFM Eight to Fourteen Modulation 8-14调制EFP Electronic Field Production 电子现场节目制作EH Ethernet Hosts 以太网主机EIN Equivalent Input Noise 等效输入噪声EIS Electronic Information System 电子信息系统EISA Extended Industrial StandardArchitecture 扩展工业标准总线EL Electro-Luminescent 场致发光EM Error Monitoring 误码监测EN End Node 末端节点ENG Electronic News Gathering 电子新闻采集EOT End of Tape 带尾EP Edit Point 编辑点Error Protocol 错误协议EPG Electronic Program Guides 电子节目指南EPS Emergency Power Supply 应急电源ERP Effective Radiated Power 有效辐射功率ES Elementary Stream 基本码流End System 终端系统ESA European Space Agency 欧洲空间局ETV Education Television 教育电视FA Enhanced Television 增强电视FABM FAS Facial Animation 面部动画FC Fiber Amplifier Booster Module 光纤放大器增强模块Fiber Access System 光纤接入系统Frequency Changer 变频器FCC Fiber Channel 光纤通道FD Film Composer 电影编辑系统Federal Communications Commission 美国联邦通信委员会FDCT Frequency Divider 分频器FDDI FDM Fiber Duct 光纤管道FDP Forward Discrete Cosine Transform离散余弦正变换FE Fiber Distributed Data Interface 分布式光纤数据接口Frequency-Division Multiplexing 频分复用FF Fiber Distribution Point 光纤分配点FG Front End 前端FH Framing Error 成帧误差FIT Fast Forward 快进FN Frequency Generator 频率发生器FOA Frequency Hopping 跳频FOC Frame-Interline Transfer 帧一行间转移Fiber Node 光纤节点Fiber Optic Amplifier 光纤放大器FOM Fiber Optic Cable 光缆FON Fiber Optic Communications 光纤通信FOS Fiber Optic Coupler 光纤耦合器FOTC Fiber Optic Modem 光纤调制解调器FS Fiber Optic Net 光纤网Factor of Safety 安全系数Fiber Optic Trunk Cable 光缆干线FT Frame Scan 帧扫描FTP Frame Store 帧存储器FTTB Frame Synchro 帧同步机FTTC France Telecom 法国电信Absorber Circuit 吸收电路AC/AC Frequency Converter 交交变频电路AC power control交流电力控制AC Power Controller交流调功电路AC Power Electronic Switch交流电力电子开关Ac Voltage Controller交流调压电路Asynchronous Modulation异步调制Baker Clamping Circuit贝克箝位电路Bi-directional Triode Thyristor双向晶闸管Bipolar Junction Transistor-- BJT双极结型晶体管Boost-Buck Chopper升降压斩波电路Boost Chopper升压斩波电路Boost Converter升压变换器Bridge Reversible Chopper桥式可逆斩波电路Buck Chopper降压斩波电路Buck Converter降压变换器Commutation换流Conduction Angle导通角Constant Voltage Constant Frequency --CVCF恒压恒频Continuous Conduction--CCM(电流)连续模式Control Circuit 控制电路Cuk Circuit CUK 斩波电路Current Reversible Chopper电流可逆斩波电路Current Source Type Inverter--CSTI 电流(源)型逆变电路Cyclo convertor周波变流器DC-AC-DC Converter直交直电路DC Chopping直流斩波DC Chopping Circuit直流斩波电路DC-DC Converter直流-直流变换器Device Commutation器件换流Direct Current Control直接电流控制Discontinuous Conduction mode (电流)断续模式displacement factor 位移因数distortion power 畸变功率double end converter 双端电路driving circuit 驱动电路electrical isolation 电气隔离fast acting fuse 快速熔断器fast recovery diode快恢复二极管fast revcovery epitaxial diodes 快恢复外延二极管fast switching thyristor快速晶闸管field controlled thyristor场控晶闸管flyback converter 反激电流forced commutation 强迫换流forward converter 正激电路frequency converter 变频器full bridge converter全桥电路full bridge rectifier 全桥整流电路full wave rectifier 全波整流电路fundamental factor基波因数gate turn-off thyristor——GTO 可关断晶闸管general purpose diode 普通二极管giant transistor——GTR 电力晶体管half bridge converter 半桥电路hard switching 硬开关high voltage IC 高压集成电路hysteresis comparison 带环比较方式indirect current control间接电流控制indirect DC-DC converter直接电流变换电路insulated-gate bipolar transistor---IGBT绝缘栅双极晶体管intelligent power module---IPM智能功率模块integrated gate-commutated thyristor---IGCT 集成门极换流晶闸管inversion 逆变latching effect 擎住效应leakage inductance 漏感light triggered thyristor---LTT光控晶闸管line commutation 电网换流load commutation 负载换流loop current 环流1 backplane 背板2 Band gap voltage reference 带隙电压参考3 bench top supply 工作台电源4 Block Diagram 方块图5 Bode Plot 波特图6 Bootstrap 自举7 Bottom FET Bottom FET8 bucket capacitor 桶形电容9 chassis 机架11 constant current source 恒流源12 Core Saturation 铁芯饱和13 crossover frequency 交叉频率14 current ripple 纹波电流15 Cycle by Cycle 逐周期16 cycle skipping 周期跳步17 Dead Time 死区时间18 DIE Temperature 核心温度19 Disable 非使能,无效,禁用,关断20 dominant pole 主极点21 Enable 使能,有效,启用22 ESD Rating ESD额定值23 Evaluation Board 评估板24 Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. 超过下面的规格使用可能引起永久的设备损害或设备故障。
Ž.Microchemical Journal672000337᎐341Fundamentals,methods and future trends ofenvironmental microwave sample preparationA.Agazzi a,U,C.Pirola ba()FKV Srl,Via Fatebenefratelli,1r5,24010Sorisole BG,Italyb()MILESTONE Srl,Via Fatebenefratelli,1r5,24010Sorisole BG,ItalyAbstractŽ.Microwave MW sample preparation has nowadays become a standard analytical tool.A large section of MW systems,such as open vessel and low to high pressure closed vessel device,are used.Theoretical and practical considerations in the development as well as implementation of MW sample preparation are presented,including methods for total implementation of MW sample preparation are presented,including methods for total decomposi-tion and leaching of trace elements in common environmental samples,such as soil,sludge,sediments,oils,biological materials,water and waste water.In particular,the US Environmental Protection Agency Office of Solid Waste methods3050B,3051,3052are discussed.Supporting reference data and documentation are presented to demon-strate specific alternative capabilities.As a natural extension of this technique,MW-based devices were more recently used to heat solvents and sample matrices as a preparation tool for extraction of organic compounds.Since 1986analysts have been using MW heating to extract various compounds from a variety of sample matrices. Information is provided about the development of an integrated MW solvent extraction technique and its capabili-ties,as well as perspective for extraction applications.The ASTM method D5765-95on solvent extraction of TPHŽ. from soils and sediment as well as the draft of a new US EPA for Volatile Organic Compounds VOCs andŽ.Semi-Volatile Organic Compounds SVOCs from environmental samples are presented.The potential benefits are analogous to those achieved by sample decomposition,i.e.reduced reaction r extraction time,improved efficiency, reduced solvent consumption and better working environment.ᮊ2000Elsevier Science B.V.All rights reserved.Keywords:Microwave technology;Closed-vessel;Acid digestion;US EPA30521.IntroductionIn the last few years the use of microwave technology for sample preparation has been U Corresponding author.widely accepted.It was not uncommon years ago to enter an analytical laboratory and to notice on one side the most advanced and sophisticatedŽ. analytical instruments ICP-AES,ICP-MS,etc. and on another side sample preparation toolsŽdating back to Lavoisier’s time heating blocks,.Bunsen burners,sand baths,etc..0026-265X r00r$-see front matterᮊ2000Elsevier Science B.V.All rights reserved.Ž.PII:S0026-265X0000085-0()A.Agazzi,C.Pirola r Microchemical Journal672000337᎐341 3382.Microwave technologyThe reasons for the large diffusion of mi-crowave technology relate to its clear advantages over more traditional technologies:a shorter acid digestion time;a supposed better recovery of volatile elements and compounds;lower contami-nation levels;minimal volumes of reagents are required,more reproducible procedures;and a better working environment.Furthermore,the closed vessel microwave di-gestion technology has a unique advantage over other closed vessel technologies.Microwaves only heat the liquid phase,while vapors do not absorb microwave energy.The tem-perature of the vapor phase is therefore lower than the temperature of the liquid phase and vapor condensation on cool vessel walls takes place.As a result,the actual vapor pressure is lower than the predicted vapor pressure.This sort of sustained dynamic,thermal non-equilibrium is a key advantage of microwave technology,as veryŽhigh temperatures and in turn short digestion .times can be reached at relatively low pressures. These days several microwave sample prepara-tion methods have been accepted by internationalw xorganizations1.3.Materials and methodsTable1lists some of the most important ap-proved methods.A brief outline of the US EPA methods3015, 3051and3052is given in Table2.Outlining in more detail the latest and more advanced method ᎏthe US EPA method3052ᎏit may be interesting to point out the requirements set re-garding the microwave unit and the pressure ves-w xsel technology2.According to the method US EPA3052, laboratories should not use kitchen type mi-crowave ovens.Instead,microwave systems should be corrosion resistant and have a well-ventilated microwave cavity.Temperature control is a must for performing the US EPA3052method,as temperature obvi-ously plays the most important role in the kinetics of the chemical reactions involved in the sample decomposition.This method also specifies the ramp time to aŽ.defined temperature5min to reach180ЊC andŽthe hold time at a given temperature10min at .180ЊC.These parameters have stimulated the develop-ment of new operating software for the most advanced commercially available microwave units. In some models,the operator has to simply draw a temperature profile,and the microwave unit microprocessor will automatically regulate the microwave power to follow this profile,as shown by in Figs.1and2.Concerning the vessel technology,the US EPA 3052requirements are for vessels made of PFATable1Most important approved methodsASTM D4309-91Standard practice for sample digestion using a closed-vessel microwaveheating technique for the determination of total recoverable metals in waterŽ.ASTM D4643-93Standard test method for the determination of water moisture contentof soil by the microwave oven methodASTM D5258-92Standard practice for acid extraction of elements from sedimentsusing closed-vessel microwave heatingASTM E1358-90Standard test method for the determination of the moisturecontent of particulate wood fuels using a microwave ovenUS EPA3015SW-846Update II Microwave assisted acid digestion of aqueous samples and extractsUS EPA3031SW-846Update III Acid digestion of oils,for metals analysis by FAAS or ICPspectroscopy-proposed microwave adaptationUS EPA3050B SW-846Update III Acid digestion of sediments,sludges,and soils-proposed microwave adaptation US EPA3051SW-856Update II Microwave assisted acid digestion of sediments,sludges,soils and oilsUS EPA3052SW-846Update III Microwave assisted acid digestion of siliceous and organically based matrices()A.Agazzi,C.Pirola r Microchemical Journal 672000337᎐341340Fig.1.Temperature profiles as drawn by the operator.or TFM fluorocarbon polymers,with a volume of 50ml or more,and with an operating pressure of 30bar or more.Also,the removal or reduction of HCl and r or HF is desirable,in this sense the US EPA method 3052is the first one to utilize the concept of a ‘total microwave sample preparation’concept.This means that the method has provisions not only for closed-vessel acid digestion,but also for the subsequent acid evaporation,to beper-Fig.2.Temperature profiles obtained after microwave heating cycle.formed,if possible,in the same microwave sys-tem.Looking at the limitations of the current closed-vessel microwave digestion technologies,perhaps the most limiting factor at present is the amount of sample that can be digested.This is particularly true for organic matrices,while this parameter is not of major concern for inorganic samples,such as minerals,ores and metals.During a microwave closed-vessel acid diges-tion,the heating raises the temperature and the vapor pressure of the solution.Furthermore,theFig.3.The digestion of bovine liver sample.()A.Agazzi,C.Pirola r Microchemical Journal672000337᎐341341Fig.4.Predigestion device with reflux glass condensers. chemical reaction itself may also generate gases further increasing the pressure inside the closed vessel.A simplified reaction between a generic organic sample and nitric acid can be summarized in this form:Ž.ORG q HNO s MetalsNO q CO gas332Ž.Ž.q NO gas q H O1x2Obviously,the larger sample amount,the higher the pressure generated by the reaction.Fig.3 shows the influence of the sample size over the total pressure generated during a closed vessel digestion at afixed temperature of180ЊC.Different quantities of BCR185Bovine Liver were digested.The lowest line represents the pressure profile when only HNO was heated at3180ЊC.The next refers to a digestion of0.25g of BCR185,and the following to0.5,0.75,1and 1.25g,respectively.It can be easily noted that a larger sample amount not only produces a higher pressure,but also a more exothermal reaction.To overcome this limitation,several attempts have been proposed.Perhaps one of the most interesting and promising is the use of an open-reflux system to predigest the sample.Once predigested,the entire vessel is transferred ᎏwithout transfer of the solutionᎏto a pres-sure rotor to complete the digestion.Fig.4shows a detail of a predigestion device,with the reflux glass condensers.Although microwave technology has entered thousands of laboratories worldwide,it is still a relatively new technology.No doubt we will see many innovations in the future,the range of applications of microwave technology extending from acid digestion to solvent extraction and or-ganic synthesis.Referencesw xŽ.1H.M.Skip Kingston,Stephen J.Haswell,in: Microwave-Enhanced Chemistry,Fundamentals,Sample Preparation,and Application;American Chemical Soci-ety,Washington,DC,pp.230᎐236.w xŽ.2H.M.Skip Kingston,Stephen J.Haswell,in: Microwave-Enhanced Chemistry,Fundamentals,Sample Preparation,and Application;American Chemical Soci-ety,Washington,DC,p.226.。
1981AgilentPNA SeriesRF and MicrowaveNetwork Analyzers2E8362/3/4A 20/40/50 GHz, 2-port, 4 receiverApplications TRL calibration for Optional features Filters, amplifiers,the most accurate allow you to add on wafer and on-wafer, in-fixture,only the capabilities in-fixture devicesand waveguide you need measurementsE8356/7/8A 3/6/9 GHz, 2-port, 4 receiver ApplicationsTRL calibration Standard front panel Filters, amplifiers, for the most accurate jumpers for highest on wafer and on-wafer and dynamic range in-fixture devices in-fixturemeasurementsStandard sourceattenuators andbias-tees for your active measurement needs E8801/2/3A 3/6/9 GHz, 2-port, 3 receiverApplications3 measurement Optional features Filters, cablesreceivers give you allow you to add high performance only the capabilities at a great value you needN3381/2/3A 3/6/9 GHz, 3-port, 4 receiverApplications Full 3-port calibration Optional features Duplexers, provides the most allow you to add couplers,accurate characterization only the capabilities circulatorsof your low-isolation you need 3-port devicesPNA Series provides…Rapid evolution of technology presents a growing challenge to component manufacturers in many industries including telecommunications, broadband, and aerospace and defense.…the Performance you Demandmeasurement needs now and well into the future.Use TRL calibration for accurate in-fixture oron-wafer measurements.Accurately measure passband ripple of low insertion lossfilters, such as DRF or LC filters, with low trace noise. Measure base station filters or LAN/receiver filtercombinations with up to 143 dB dynamic range.4Built for SpeedDecreasing test time is critical for your success in the market-place. The PNA Series analyzers are designed with maximum throughput in mind. Use a variety of powerful tools to optimize your measurement processes.Reduce test time with fewer connectionsConnect your 3-port device once for full characterization in just 3sweeps with the new 3-port PNAs.(see specific models on page 11)Decrease calibration time with easy-to-use electronic calibration (ECal)Perform fast, accurate, automatic calibrations with Agilent’s ECal products. Control ECal directly from the analyzer without an external PC.Dramatically increase throughput with segment sweep modeOptimize each sweep by collecting data at frequency segments you define. Specify each segment with the optimum number of points, IF bandwidth and power level for increased speed and dynamic range.Reduce test time with pass/fail testingLet the network analyzerdetermine if measurement results are within limits that you define.Specify limits easily using the limit table.…the Throughput you Strive forReduce test time with a network analyzer optimized to increase throughput.5Gain a competitive advantage withpowerful automation toolsAutomated test is yet another method you can use to eliminate valuable seconds from your test process. Use the flexible automation environment to lower your cost of test.•Control the analyzer using SCPI commands, or gain the speed and connectivity advantage of COM/DCOM.•Execute code directly from the analyzer, or from an external PC through LAN or GPIB.•Develop code in the programming language you want. Languages like Visual Basic, Visual C++,Agilent-VEE, or LabView ™.The COM/DCOM advantage•Quick data transfer rate (<1 ms COM, 50 ms SCPI over GPIB) •Swift command execution •Fewer lines of code•Re-use rather than re-write objects6…the Connectivity you Dream ofSave data easily to floppy disk, internal hard drive, or your external CD-RW drive, PC or server using the familiar Windows ®interface.Import trace data and screen images directly into your Microsoft ®Excel or Word applications using Agilent IntuiLink for post-processing on the analyzer.Download IntuiLink free at:/find/intuilinkSend results to printers over LAN, parallel,serial or USB interfaces.Send test data to a central file server.Access the analyzer remotely for additional troubleshooting capability.variety of I/O interfaces includingGPIB, USB, LAN and parallelconnections.78…the Flexibility you DesireArrange windows for custom viewing or select standard viewing configurations.configurations.The PNA Series family combines powerful features with the benefit of Windows to provide maximummeasurement flexibility and versatility.•Configure up to 16 independent stimulus settings in a single instrument state.•Display up to 4 active traces in each window.•Select 10 coupled or fully-independent markers per trace.High power measurements•Use the configurable test set option to add your own external components in the measurement path.•Internally controlled step attenuators in the source and/or receiver path give you a greater power range.•Bias-tees supply DC power to your active components.High-rejection measurements•Obtain maximum dynamic range at the test port with full 12-term error correction using the configurable test set option.Time-domain analysis•Locate and resolve discontinuities in your device,fixture or cable. Once located, use gating to remove unwanted responses.•Tune cavity-resonator bandpass filters quickly with a simple, deterministic method.9…the Ease of Use you SeekEasily enter limit line and segment sweep values.View choices easily with drop down menus.Input parameters quickly using active entry toolbars.Set up fundamental measurements quickly using front panel keys.Answers when and where you need them with embedded helpAccelerate learning withcontext-sensitive help and robust tutorials. Use on-line help to quickly reference programming and user documentation in French,German, Japanese, Spanish or English languages. Now you can use Favorites to bookmark important topics.Configure measurements easily with intuitive user interfaceNavigate the analyzer efficiently using familiar front panel keys or with a mouse. Use a mouse or hard keys independently, or in combination to best suit your needs. Both methods are optimized in the Windows® environment for fast, intuitive operation.10…the Total Solutions you DeserveCharacterize your balanced devicesReduce training and test time for filtersAgilent’s balanced-measurement systems make complex characterization of fully balanced or bal-anced-to-single-ended RF components a lot easier.Devices such as differential filters and amplifiers,baluns, and balanced transmission lines that were once difficult to measure using a conventional two-port measuring system, can now be completely and accurately tested with Agilent’s solutions. For more information visit/find/balanced For manufacturers of high-performance bandpass filters, Agilent’s new N4261A filter tuning software is the only solution that allows inexperienced filter tuners to rapidly tune multiple-pole filters after only brief instruction. Agilent’s filter tuning software is the industry's first complete solution that helps manufacturers reduce average filter alignment times and significantly reduces personnel training times. For more information visit /find/ftsCalibrate effortlessly with ECalElectronic calibration (ECal) is a precision, single connection, one or two-port calibration technique for Agilent vector network analyzers. ECal offers a full two-port calibration with a single connection to the ECal module with minimal operator interaction.You get faster results, more repeatable calibrations,and less wear on the connectors. PNA Series compatible modules are available to 9 GHz. For more information visit /find/ecal…the Information you Can Rely on Key SpecificationsMeasurement speed (35 kHz IF bandwidth)Model Frequency Points Cycle time (ms)3µs/point Updates/secondAll 1.8 GHz - 2 GHz101989111All 1.8 GHz - 2 GHz1601563518All300 kHz - 9 GHz2015728418E8362/3/4A45 MHz - 20/40/50 GHz201115/160/200746/776/9958/6/5E8362/3/4A45 MHz - 20/40/50 GHz1601135/230/25584/147/1597/4/4Data transfer speed, 32-bit binary (ms)4201 points1601 pointsCOM523 SCPI539 DCOM6314 SCPI over GPIB6957 SCPI over LAN612281.To achieve the highest dynamic range requires receiver access. Thecombination of source and receiver access allows for the highestdynamic range with full 12-term error correction.2.Port 1 = Power source from Port 1;Port 2, 3 = Typical performance power source from Port 2 or 33.Typical performance; includes retrace and band switching times withresponse calibration; full two-port calibration approximately doublescycle time4.Typical performance5.Program executed in the network analyzer6.Program executed on an external PCRF MicrowaveModel E8356/7/8A E8801/2/3A N3381/2/3A E8362/3/4AFrequency range300kHz - 3/6/9 GHz45MHz - 20/40/50 GHzNumber of ports2232Measurement receivers4344Configurable test set1Receiver access Standard Option 014Option 014Option 014Source access Option 015Option 014Option 014Option 014Extended power range Standard Option 1E1Option 1E1Option UNLHigh stability timebase Standard Option 1E5Option 1E5StandardBias tees Standard––Option UNLTime domain Option 010Option 010Option 010Option 010ECal support Yes Yes Yes NoDynamic range (at test port)Port 1/Port 2, 32300 kHz - 1 MHz125 dB125 dB125 dB/123 dB45 MHz - 2 GHz94 - 119 dB1 MHz - 3 GHz128 dB128 dB128 dB/126 dB2 GHz - 20 GHz122 dB3 GHz - 6 GHz118 dB118 dB118 dB/116 dB20 GHz - 40 GHz110 dB6 GHz - 9 GHz113 dB113 dB113 dB/113 dB40 GHz - 50 GHz104 dBDynamic range (receiver access)Port 1/Port 2, 32300 kHz - 1 MHz140 dB140 dB140 dB/138 dB45 MHz - 2 GHz132 dB1 MHz - 3 GHz143 dB143 dB143 dB/141 dB2 GHz - 20 GHz136 dB3 GHz - 6 GHz133 dB133 dB133 dB/131 dB20 GHz - 40 GHz119 dB6 GHz - 9 GHz128 dB128 dB128 dB/128 dB40 GHz - 50 GHz111 dBTrace noise (1kHz IF BW)300 kHz - 9 GHz<0.002 dB<0.002 dB<0.002 dB45 MHz - 50 GHz<0.006 dB<0.010 deg rms<0.010 deg rms<0.010 deg rms<0.1 deg rmsMaximum output powerPort 1/Port 2, 32300 kHz - 6 GHz+10 dBm+10 dBm+10 dBm/+8 dBm45 MHz - 10 GHz+5 dBm6 GHz - 9 GHz+5 dBm+5 dBm+5 dBm/+5 dBm10 GHz - 20 GHz+3 dBm20 GHz - 40 GHz-4 dBm40 GHz - 45 GHz-5 dBm45 GHz - 50 GHz-10 dBm11Key web resourcesVisit our wireless component manufacturerindustry area at:/find/wireless Visit the PNA Series home page at:/find/pnaFor further information about Agilent’s service and support products, please visit:/find/tm_servicesAdditional literaturePNA Series, RF Data Sheet, publication #5980-1236EPNA Series, RF Configuration Guide, publication #5980-1235EPNA Series, Microwave Data Sheet, publication #5988-3992ENPNA Series, Microwave Configuration Guide, publication #5988-3993ENExpand your measurement capabilities with Agilent-qualified Channel Partners.Our Channel Partners offer accessories and measurement solutions that extend your network analysis capabilities.For information about test fixtures and part handlers, contact:Inter-Continental Microwave 1515 Wyatt DriveSanta Clara, CA 95054 USA Telephone: (408) 727-1596Fax: (408) 727-0105Web site: E-mail:******************For information about probing equipment and accessories, contact:Cascade Microtech, Inc 2430 NW 206th Avenue Beaverton, OR 97006 USA Telephone: (503) 601-1000Fax: (503) 601-1002Web site: E-mail:****************Probe station (page 3) courtesy of Cascade Microtech, Inc.Part handler (page 4) courtesy of Inter-Continental MicrowaveMicrosoft ®and Windows ®2000 are U.S. registered trademarks of Microsoft, Corporation.Imagine What you can Achieve Using Agilent’s New Approach to Network Analysis…Agilent Technologies Test and Measurement Support, Services, and AssistanceAgilent Technologies aims to maximize the value you receive, while minimizing your risk and problems. 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技术和食物准备的英语作文Technology and food preparation are two essential aspects of modern life. The advancement of technology has greatly impacted the way we prepare and cook our food. From the invention of the microwave to the development of high-tech kitchen appliances, technology has revolutionized the way we approach food preparation.When it comes to food preparation, there are a variety of techniques and methods that can be used. Whether it's grilling, roasting, baking, or sautéing, each method requires a different set of skills and tools. With the help of technology, these processes have become more efficient and convenient, allowing us to prepare our meals with greater ease and precision.In today's digital age, there are countless apps and online platforms dedicated to food preparation and cooking. These resources provide a wealth of recipes, cooking tips, and instructional videos that can help even the mostinexperienced cooks create delicious and impressive dishes.Furthermore, the use of smart kitchen appliances has made food preparation more streamlined and efficient. From smart ovens that can be controlled remotely to high-speed blenders that can whip up smoothies in seconds, these appliances have transformed the way we approach cooking.In addition to technology, the availability of freshand high-quality ingredients is crucial for successful food preparation. Whether it's sourcing locally grown produce or selecting the finest cuts of meat, the quality ofingredients can greatly impact the outcome of a dish.In conclusion, the intersection of technology and food preparation has resulted in a myriad of advancements that have made cooking more accessible, efficient, and enjoyable. As technology continues to evolve, it will undoubtedly play an increasingly important role in shaping the future offood preparation.。
宇宙怎样运转英语作文How the Universe Works。
The universe is a vast and complex system that has captivated the human imagination for millennia. From the earliest civilizations to modern-day scientists, people have sought to understand how the universe works. In this essay, we will explore some of the key concepts that help us understand the workings of the universe.Firstly, let's consider the Big Bang theory. This theory proposes that the universe began as a singularity, an infinitely dense and hot point in space and time. Around 13.8 billion years ago, this singularity exploded, creating all the matter and energy in the universe. The universe has been expanding ever since, and this expansion is still ongoing.One of the key pieces of evidence for the Big Bang theory is the cosmic microwave background radiation. Thisis a faint glow of radiation that permeates the entire universe, and it is thought to be the afterglow of the Big Bang. It was first detected in 1964 by two radio astronomers, Arno Penzias and Robert Wilson, who were studying radio waves in space.Another important concept in understanding the universe is gravity. Gravity is the force that governs the motion of all objects in the universe, from the tiniest particles to the largest galaxies. It is what holds planets in orbit around stars and stars in orbit around the center of their galaxies.The theory of general relativity, developed by Albert Einstein, is the most accurate description of gravity we have. According to this theory, gravity is not a force that acts between objects, but rather it is the curvature of space and time itself. Objects with mass cause a curvature in space-time, and other objects are then attracted to this curvature.The study of galaxies is another important area ofresearch in understanding the universe. Galaxies are massive collections of stars, gas, and dust that are held together by gravity. There are billions of galaxies in the universe, each with its own unique structure and characteristics.Our own galaxy, the Milky Way, is a spiral galaxy that contains around 100 billion stars. It is thought to have formed around 13.6 billion years ago, shortly after the Big Bang. The center of the Milky Way contains a supermassive black hole, which is thought to be around 4 million times the mass of the sun.Finally, let's consider the concept of dark matter and dark energy. These are two mysterious substances that are thought to make up the majority of the universe, but we cannot see or detect them directly. Dark matter is thought to be a type of matter that does not interact with light, while dark energy is a force that is causing the expansion of the universe to accelerate.In conclusion, the universe is a complex andfascinating system that has been the subject of study for thousands of years. From the Big Bang to the study of galaxies and the mysteries of dark matter and dark energy, there is still much we have yet to discover. However, with each new discovery, we come closer to understanding the workings of the universe and our place within it.。
Microwave assisted synthesis of zeolite A from metakaolinSathy Chandrasekhar *,P.N.PramadaChemical Sciences Division,Regional Research Laboratory,Thiruvananthapuram 695019,Kerala,IndiaReceived 4July 2006;received in revised form 17March 2007;accepted 3April 2007Available online 21April 2007AbstractZeolites are generally synthesized by the hydrothermal reaction of sodium aluminosilicate gels prepared from pure chemicals in alka-line medium using conventional heating systems.In the present study,microwave energy is used as a novel heating tool for the synthesis of zeolite A and metakaolin (Al 2O 3Æ2SiO 2),a calcined product of kaolin (Al 2O 3Æ2SiO 2Æ2H 2O)has been taken as a combined source for silica and alumina.Optimization studies on various reaction parameters have been conducted.Phase pure zeolite A of high crystallinity was synthesized by heating the reaction mixture for 2h at 85°C under microwave hydrothermal system where as conventionally it takes 6–8h.However,initial microwave exposure for 2min at 85°C and 20h ageing at room temperature was found to be a pre-requisite for the crystallization of zeolite A in this system.The products and intermediates at different stages of the reactions were characterized using XRD,IR,solid state NMR and chemical analysis.Morphology was examined using SEM.The crystallization of the zeolite was followed by measuring the water capacities of the product in each experiment.Calcium binding capacity of selected products was also determined.A comparative study of the zeolite A formation from metakaolin under microwave and conventional hydrothermal systems was also carried out.Ó2007Elsevier Inc.All rights reserved.Keywords:Zeolite A;Metakaolin;Microwave;Synthesis;Characterization1.IntroductionZeolites are porous three dimensional aluminosilicates formed by the sharing of oxygen atoms in the frame work aluminium and silicon tetrahedra [1].Out of the various low silica zeolites,Zeolite A is of great commercial impor-tance due to its molecular sieving and ion exchange prop-erties [2].Zeolites are conventionally synthesized from sodium aluminosilicate gel prepared from pure chemicals in air ovens or auto claves [2].Metakaolin (Al 2O 3Æ2SiO 2),a calcined product of kaolin (Al 2O 3Æ2SiO 2Æ2H 2O)with Si/Al ratio $1is a convenient starting material for the syn-thesis of zeolite A [3–5].Microwave energy is a powerful heating source which has not been studied extensively in zeolite synthesis.Thefirst patent is by Chu et al.which reported the synthesis of zeolite A in 12min under microwave heating [6].How-ever,the product was contaminated with hydroxy sodalite and zeolite A was obtained only after prolonged heating.A review on the microwave techniques in zeolite synthesis was reported by Cundy in 1998[7].Slangen et al.reported the effect of ageing on the formation of zeolite A under microwave conditions [8].They reported that ageing of the reactant mixture is a pre-requisite for fast crystalliza-tion of the zeolite.Since the heating by microwaves is rapid,preparation of the reaction mixture has to be more stringent compared to that in the conventional method to get the desired product.Sufficiently aged mixtures can yield zeolite A with crystal sizes ranging from 0.1to 0.3l m,after 1min heating in the microwave.It was also found that zeolite crystallisation from an unaged system can be improved dramatically by adding aged synthesis mixture to it.This suggests that rearrangement of the reaction mix-ture to yield suitable nuclei is the bottle neck in the microwave heating.A two stepped heating at different1387-1811/$-see front matter Ó2007Elsevier Inc.All rights reserved.doi:10.1016/j.micromeso.2007.04.003*Corresponding author.Tel.:+9104712515223;fax:+9104712491712.E-mail address:chandrasekharsathy@rediff (S.Chandrase-khar)./locate/micromesoAvailable online at Microporous and Mesoporous Materials 108(2008)152–161temperatures is reported for the synthesis of zeolite A.i.e. 90s at120°C and then5min at100°C.Microwave assisted crystallization of zeolite A from dense gels was reported by Bonaccorsi et al.[9].Pure zeolite A has been obtained,in a total processing time of1h,by exposing the reaction mixture to a microwave electromagneticfield under atmospheric pressure.A single step with only one output power level was found to be unsuitable for crystal-lizing pure zeolite,even with different exposure times.Fur-ther,it was demonstrated as to how an adequate tailoring of the microwave energy released to a synthesis mixture can lead to pure zeolite A without pre-treatment of the solution.Long ageing is not required and application ofmicrowave radiation is not detrimental even in thefirst stage of the synthesis when a thick gel is formed and nucle-ation has to begin.Finally,it has been established that the strong dissolution effect associated with the oscillating elec-tromagneticfield can be used to reduce water content in zeolite formulation,increasing the yield and production capacity to a point where conventional synthesis leads to impurity formation.Romero synthesized zeolite X by microwave heating and studied its catalytic activity[10].Katsuki et pared microwave and conventional hydrothermal synthesis of zeolite Y.They found that crystallization of zeolite Y in microwave treatment led to increased rate of formation by3–4times than via conventional hydrothermal treatment [11].Somani et al.synthesized ZSM-5at an enhanced crys-tallization rate using microwave energy[12].Inada et al. synthesized zeolite P1from coalfly ash through microwave hydrothermal reaction.They found that the microwave is effective to produce the zeolite from coalfly ash in a short period by control of irradiation schedule in the early stage [13].In all the reported studies on the synthesis of zeolites, sodium aluminosilicate gels prepared from pure chemicals have been taken as the starting material.Even though a number of papers are reported on this,no systematic study has so far been reported on the formation of zeolite A from metakaolin.The present study aims at the optimization of various reaction parameters for the synthesis of zeolite A from metakaolin under microwave(MW)conditions.A comparative study of the zeolite A formed under micro-wave and conventional systems using metakaolin was also carried out.2.Experimental2.1.Raw materialCoating grade kaolin of high purity(Table1)supplied by M/s English Indian Clays Ltd.,Thiruvananthapuram and technical grade sodium hydroxide was used for the synthesis.Metakaolin was prepared by heating the kaolin at700°C for2h at a heating rate of5°C/min in a muffle furnace with a temperature programmer.2.2.SynthesisA fabricated multi mode microwave reactor(MSS05 microwave sintering system)with a thermocouple and pro-grammer for accurate setting and measurement of temper-ature(M/s SV Heat Engineering,Hyderabad)was used for conducting the experiments.Sodium aluminosilicate gel was prepared with the molar ratios SiO2/Al2O3=2;Na2O/SiO2=2.5and H2O/ Na2O=40by mixing calculated amounts of metakaolinite and sodium hydroxide solutions[4].NaOH was dissolved in distilled water and metakaolin was slowly added to the alkali and a thorough mixing was done to get uniformity. The reaction mixture was transferred into100ml teflon vessel and a series of experiments were conducted under different conditions such as ageing time(keeping the sam-ple after mixing for a particular time),heating(reaction) time and temperature(heating the mixture under micro-wave),seeding,etc.Effect of initial microwave exposure of the mixture for a short period before ageing was also studied.The microwave heating was carried out at 2.45GHz and800W.The vessel was not befilled more than50%as a precaution.After each reaction,samples were immediatelyfiltered,washed with alkaline water (pH9–10)and driedfirst over a water bath and then at 110°C for1h.They were then hydrated to equilibrium water content by exposing them to water vapor from satu-rated NaCl solution before characterization.Zeolite A prepared by conventional methods was used as seed material to study its effect on the initiation of the zeolite crystallization.Very small quantities of the zeolite were added in the reaction mixture before the ageing/ hydrothermal treatment.2.3.CharacterizationX-ray diffraction of the sample was carried out in an X’Pert Pro X-ray Diffractometer using Cu K a radiation. The phases formed were identified by comparing the d spacing and relative intensities of the samples with stan-dard reference data in JCPDSfile[14].IR spectra of samples were scanned using a Perkin–Elmer882IR spectrophotometer was used to take the IR Table1Chemical composition of kaolinConstituents%(wt)Theoretical(kaolinite) SiO245.9046.52Al2O338.9039.53Fe2O30.51–TiO20.49–CaO0.05–MgO0.04–Na2O0.08–K2O0.03–LOI13.8013.95Si/Al ratio 1.003 1.0S.Chandrasekhar,P.N.Pramada/Microporous and Mesoporous Materials108(2008)152–161153spectra of the samples in the range400–4000cmÀ1[15]. Morphology of the samples was examined using a scanning electron microscope,JEOL JSM5600LV.Chemical analysis of the product zeolite was carried out essentially tofind out the Si/Al ratio using standard wet chemical analysis procedure[16].Solid state29Si and27Al NMR spectra of the samples were taken using a DSK 300NMR Spectrometer at59.63and78.21MHz, respectively.The conventional method of heating the samples at 300°C for2h,cooling in a desiccator and rehydrating to the equilibrium water content was adopted for the determi-nation of water adsorption capacity of selected samples[4]. Nearly1g of the zeolite was accurately weighed(a)and heated in a muffle furnace to300°C and a holding time of2h was given.The sample was then cooled in a desicca-tor and again weighed(b).The wt.loss is termed as uncal-cined water capacity(UWC)UWC%¼½ðaÀbÞ=b Â100The sample was kept in a hydrator maintained at35% relative humidity by a saturated solution of NaCl for 24h and then weighed(c).The increase in wt.due to the adsorption of water is termed as the calcined water capac-ity(CWC)[17]CWC c%¼½ðcÀbÞ=b Â100The%crystallinity of the zeolite formed was calculated from the calcined water capacity values.The crystallinity of the products can be directly calculated from the CWC value as%crystallinity¼f½CWCÀCWC a =½CWC cÀCWC a gÂ100 where CWC is the theoretical value of zeolite A(22.19)cal-culated from the molecular formula,CWC a is the value for the amorphous phase(2.93),CWC c is that for the products.The calcium binding capacity(CBC)was determined by exchanging the sodium form of zeolite with calcium ion. An accurately weighed sample was stirred with a standard solution of Ca(300mg of CaO per litreÀ0.786g of CaCl2Æ2H2O dissolved in distilled water and made up to 1l)for10min andfiltered.Thefiltrate was analyzed for its Ca content by complexometry and the difference is attributed to the exchanged amount.The values are expressed as milli equivalence of CaO per gram of zeolite.For the estimation of Ca,10ml of thefiltrate was mixed with25ml2N NaOH and0.2g of P&R indicator and immediately titrated with standard EDTA till the colour of the solution changed from pink to blue(a ml) %CaO=[a·X·100]/w where X=Equivalent CaO in g/ml of EDTA and W=weight of the sample3.Results and discussionThe kaolin under study has a chemical composition as given in Table1and the major constituents are silica and alumina.The concentration of other elements like sodium, potassium,calcium,iron and titanium are very low indicat-ing the high purity of kaolin.The mineralogy studied by XRD analysis confirms that the sample contains high amount of kaolinite and ancillary minerals content is too low to be detected/identified by this technique[5].The loss on ignition corresponds to the water of hydration.A series of experiments were conducted to synthesis zeo-lite A from the metakaolin under microwave(MW)condi-tion.Different sodium aluminosilicate gels were prepared by mixing the reactants at different conditions and the sam-ples are designated as MKAG1-7(Table2).The reaction conditions,values of water capacities and the%crystallin-ity of the products for MW reactions are given in Tables 3a–3e.Details of the products of reactions after mixing and heating for different duration at85°C are given in Table3a.Change in the properties of the products obtained by heating the samples for different timing and at different temperatures is given in Table3b.The reaction mixtures aged for20h at room temperature and heated at 85°C for different timings give products as presented in Table2Formation conditions for gelsSample Initial MW(min)Ageing(h)Seed(%) MKAG1–––MKAG2–20–MKAG32––MKAG4–201 MKAG5220–MKAG6001 MKAG7221Table3aReaction conditions and properties of products from MKAG1(85°C) Sample MW heating(min)UWC(%)CWC(%) MKA11011.66 1.49 MKA22010.12 1.69 MKA33016.22 1.95 MKA46018.71 1.38 MKA59010.51 1.29 MKA612019.25 6.68 MKA715011.4610.67 MKA824021.3721.75Table3bReaction conditions and properties of products from MKAG1at different temperaturesSample MW heating UWC(%)CWC(%) Temperature(°C)Time(min)MKA9906018.17 1.71 MKA10956020.90 1.88 MKA119512016.16 1.8 MKA121101033.40BDL MKA131103021.16 1.83 MKA141106017.3315.58154S.Chandrasekhar,P.N.Pramada/Microporous and Mesoporous Materials108(2008)152–161Table 3c .Reactions with different seeding conditions were also tried and are given in Table 3d .Reaction conditions such as the time of initial microwave exposure,ageing and heating and the properties of the products obtained are given in Table 3e .The products are designated as MKA1-54.The sample MKA55is the product formed under a combination of microwave and conventional heat-ing.MKA56is the sample after 4h heating (with out initial MW exposure)in a conventional air oven.3.1.Water capacitiesAmorphous products lose their porosity during heating and cannot be further dehydrated.Crystalline products retain their porosity even after heating at 350°C for 1h which shows the stability of zeolite network structure.When the UWC and CWC values come closer to each other and nearer to 22.19(theoretical value of zeolite A),the crystallinity of the sample becomes high provided the zeolite formed is phase pure.The crystallinity of the zeolite is thus directly correlated to its CWC and hence the zeolite crystallization is monitored by determining the same.The reactants were mixed and heated to 85°C for differ-ent duration under MW condition.Tables 3a and 3b show the results obtained using the gel named MKAG1.No crystalline product was formed up to 90min.Zeolite A started crystallizing after 120min and highly crystalline product (MKA8)was obtained after 4h reaction (Fig.1and Table 3a ).Effect of temperature on the hydrothermal reaction was studied (Table 3b ).No zeolite formation is observed by simply mixing the reactants and heating for 60min at 95°C (MKA10).Zeolite A with moderate crystallinity was formed after 60min heating at 110°C (MKA14).Var-iation of %crystallinity with reaction temperature is given in Fig.2.It is seen that above 100°C,the effect of micro-waves on the rate of crystallization is very high.The forma-tion of zeolites takes place under autogeneous pressure.Above 100°C,the water vapour also contributes to the pressure inside the vessel and therefore faster crystalliza-tion takes place.More over,microwaves act strongly on water in vapor phase.Under microwave heating,formation of nuclei is found to be the limiting factor.Ageing is a nucleation aiding stepTable 3cReaction conditions and properties of products from MKAG2(85°C)Sample MW heating (min)UWC (%)CWC (%)MKA15510.82 1.8MKA161013.370.9MKA172018.180.93MKA183015.35 1.23MKA196016.48 1.47MKA2012018.74 2.89MKA2124015.4610.67Table 3dReaction conditions and properties of products (85°C)–different seeding and heating SampleInitial MW (min)Ageing (h)Seed (%)MW heating (min)UWC (%)CWC (%)MKA22––11018.77 1.63MKA23––13013.55 1.62MKA24––16033.18 1.50MKA25––112018.74 2.89MKA26–2011015.75 1.33MKA27–2013019.210.93MKA28–2016018.60 1.49MKA29–20112017.5 6.81MKA302216015.52 2.0MKA312112013.283.56Table 3eReaction conditions and properties of products (85°C)–different initial MW heating and ageing times Sample Initial MW (min)Ageing (h)MW heating (min)UWC (%)CWC (%)MKA320.5212013.86 1.49MKA33512018.618.24MKA342012014.62 2.25MKA351212013.86 1.49MKA36512013.78 1.3MKA372012020.3216.87MKA38226053.07 2.05MKA39212014.56 4.9MKA4059013.35 1.7MKA41512013.93 4.68MKA42159010.76 1.9MKA431512016.512.28MKA44203014.32 1.65MKA45209014.91 1.74MKA462010013.59 4.99MKA472012048.4522.30MKA484412017.8314.25MKA495212020.54 1.79MKA50512015.42 2.8MKA512012015.4010.44MKA5210212010.39 5.52MKA53512014.54 1.55MKA542012014.427.48aMKA552(MW oven)4h a (air oven)aMKA56––4h a (air oven)aConventional heating.S.Chandrasekhar,P.N.Pramada /Microporous and Mesoporous Materials 108(2008)152–161155in the synthesis of zeolites.It was reported that during the ageing period,pre-nuclei are formed.Nuclei can be defined as the smallest viable system capable of forming an identi-fiable crystal phase that can induce crystal growth.For the formation of these nuclei,first the synthesis mixture should be mixed thoroughly to ensure mixing on a molecular scale. It is expected that these nuclei are more abundant in the longer aged synthesis mixture and therefore the reaction time for crystallization gets reduced.Slangen et al reported that for longer aged synthesis mixtures,the heating time does not reduce significantly and ageing has distinct effect only on the crystal size[8].When20h ageing was given to the reaction mixture before MW heating(Table3c),zeolite A with very low crystallinity is formed after120min at85°C(MKA20). The product obtained after4h heating is moderately crys-talline(MKA21).So ageing of the reaction mixture alone does not have much influence in the formation of nuclei of zeolite A from metakaolin under MW conditions.Mixing on a molecular scale is essential for the nucle-ation of zeolite A.Pockets of silica and alumina are formed during the dissolution of metakaolin in alkali which undergo a rearrangement during ageing.In course of time, these pockets combine to form silica-alumina oligomers, with a silicon aluminium ratio of one.Thorough mixing also removes any pockets in which hydroxy sodalite can nucleate.When metakaolin is mixed with alkali,it takes some time to dissolve the metakaolin and form the reactive species.In conventional synthesis the dissolution and the formation of the nuclei takes place during the slow heating. Since microwave heating is very fast,dissolution and orga-nization has to be carried out before heating.Some experiments were carried out by seeding the reac-tion mixture with zeolite A(1%)and applying various reac-tion conditions like,with and with out ageing,2min initial MW exposure and ageing(MKA22-29)(Table3d).It has been observed that seeding does not have much influence in the nucleation/crystallization rate.An initial short microwave exposure is found to favor the dissolution of metakaolin in alkali(samples MKA30-54,Tables3d and3e)When ageing was given after this short MW exposure,the nucleation of zeolite A is very much enhanced and thus crystalline product is formed.Different short initial MW exposure timings from30s to 10min were tried.A series of reactions with different initial MW exposure(0.5,1,2,5and10min)and ageing times(2, 5and10h)was carried out tofind out the optimum expo-sure time to form crystalline zeolite A.Product with max-imum crystallinity is obtained by irradiating the reaction mixture for2min,ageing for20h and heating2h under MW condition(MKA47)(Fig.3).The reaction mixture aged for short durations contains some pockets of inade-quate mixing(along with the zeolite nuclei)which is the reason for the formation of amorphous material.An initial longer heating time than2min has a retarding effect on the formation of zeolite A(Fig.4).This is because there is an optimum MW energy for the effective orientation of the reactive species to form the zeolite nuclei.When the initial heating time is increased,the reactant species do not get organized and the formation of nuclei becomes difficult.The short MW exposure has very significant role on the synthesis of zeolite A from metakaolin.Reduction of syn-thesis time for crystalline zeolite A from metakaolin under156S.Chandrasekhar,P.N.Pramada/Microporous and Mesoporous Materials108(2008)152–161MW condition is actually achieved through the rate enhancement in the dissolution step(Fig.3).Heating of the reaction mixture for4h in MW condition is result in the formation of highly crystalline zeolite A(MKA8), where as zeolite A with lower crystallinity is formed in the conventional system(MKA56).If an initial2min MW exposure was given to the reaction mixture and heated in an air oven for4h,zeolite A having almost same crystal-linity as MKA8is formed(MKA55).On the contrary6–8h heating is required for the formation of crystalline zeolite A in the conventional synthesis.Efficient synthesis demands carefully controlled initial MW exposure and ageing before heating.When the%crys-tallinity of products is plotted as a function of time,an‘S’shaped curve is obtained.This suggests that crystal growth is preceded by a distinct,slow,nucleation step and a proper understanding of this step is the key to control the synthe-sis conditions[18].3.2.X-ray diffraction analysisXRD patterns of the metakaolin and intermediate gels formed at different stages are shown in Fig.5.Metakaolin has a pattern with a broad hump having maximum at 2h=$22°.The gels formed by mixing the metakaolin with alkali also give amorphous broad bands,but with varia-tions in the height,width and position.These variations are indicative of the differences in the structural environ-ments.The gel formed just after mixing(MKAG1)has the same pattern as metakaolin but with a less hump height.Gel after20h ageing(MKAG2)and the one after 2min MW exposure(MKAG3)show humps slightly broader than that of MKAG1.When1%seeding and 20h ageing was given to the reaction mixture the gel formed is almost like G3but with more broadened band (MKAG4).When2min initial MW exposure and20h age-ing was given,the gel formed is having a hump with a max-imum at2h=$28°(MKAG5).Fig.6gives the XRD patterns of the product after 120min heating(MKA6),after20h ageing and different heating time(MKA18,MKA19and MKA20),the product after20h ageing,with1%seeding and120min heating (MKA29)and the kinetic series after2min initial MW heating and20h ageing(MKA45,MKA46and MKA47).It has been observed that the product with max-imum crystallinity is MKA47formed from the gel MKAG5.Zeolite A with only moderate crystallinity was formed after20h ageing,with1%seeding and120min heating(MKA29)and zeolite A with lower crystallinity by heating the reaction mixture for120min(MKA6), and after20h ageing and120min heating(MKA20).The XRD results are in good agreement with the%crystallinity values and therefore substantiate the values of calcined water capacity.When the reaction mixture after2min ini-tial MW exposure is subjected to conventional heating for 4h,the product obtained is phase pure zeolite(MKA55) with the same crystallinity as obtained after4h heatingS.Chandrasekhar,P.N.Pramada/Microporous and Mesoporous Materials108(2008)152–161157under MW condition(MKA8).Zeolite A with lower crys-tallinity is formed when the reaction mixture was not exposed to initial MW exposure and was heated4h in air oven(MKA56).The XRD analysis support the fact that when the reac-tion mixture is subjected to a microwave exposure for 2min,ageing for20h and heating for2h,zeolite A with maximum crystallinity is formed.The gel MKAG5is found to have the‘‘ideal precursor gel structure’’for the crystal-lization of zeolite A.3.3.Infra red spectraThe spectra of the gel samples formed after(i)mixing (MKAG1),(ii)mixing and20h ageing(MKAG2),(iii) mixing and2min initial MW(MKAG3)and(iv)2min MW and20h ageing(MKAG5)are taken and given in Fig.7.But no characteristic band of zeolite A is observed in the spectra of the gel samples.The spectra of the selected products(MKA46and MKA47)are also given in Fig.8. The typical bands of zeolite A representing theasymmetric Fig.8.Solid sate27Al and29Si NMR spectra of selected samples.a–MK,b–MKAG1,c–MKAG2,d–MKAG3,e–MKAG4,f–MKAG5and g–MKA47. 158S.Chandrasekhar,P.N.Pramada/Microporous and Mesoporous Materials108(2008)152–161and symmetric stretches(1050and74cmÀ1),double rings(557cmÀ1)and T–O bend(465cmÀ1)are observed inMKA47and these bands are less intense in MKA46.TheIR spectral analysis is found to substantiate the XRDresults.3.4.29Si and27Al solid state NMR spectraAluminosilicates like clays and zeolites contain SiO4andAlO6/AlO4units and can be studied by the29Si and27Alsolid state NMR spectroscopy.This technique is a power-ful tool for understanding the structure of various reac-tants,intermediates and products in the synthesis ofzeolites,especially those of the intermediates which areamorphous to X-rays.In the29Si spectrum,there are char-acteristic lines for silicon atoms having different environ-ments like Si–O–Al linkages with1,2,3or4Al atoms.The chemical shift values are different for Al atoms with4,5and6coordination in the27Al NMR spectrum.The 29Si and27Al solid state NMR spectra of the metakaolin, gels prepared at various conditions and product zeoliteare given in Fig.8.3.4.1.29Si spectraMetakaolin shows a broad line atÀ97.5ppm which ischaracteristic of silicon atoms in a highly disordered stateas found in amorphous silicates.When kaolinite is dehydr-oxylated,the silicon atoms experience a range of environ-ments of differing distortion and the broadness ofmetakaolinite line is attributed to these variations in theSi–O–Si(Al)bond angles[19].The gel MKAG1has a sim-ilar spectrum(silicon line atÀ99.5ppm)indicating that nochange takes place just after mixing the metakaolin withalkali.After giving an ageing of20h to this,the gelMKAG2gives a small and broad silicon line atÀ89.4ppm.MKAG4is similar to MKAG2.The silicon atoms in this sample appear to have more distorted struc-ture.The distortion in MKAG3and MKAG5is so high that no silicon line is observed in their spectra.The product formed from MKAG5gives sharp single line atÀ89.5ppm which is typical of Si(4Al)units(MKA47).3.4.2.27Al spectraMetakaolin gives a broad line at$6.2and a small line at $24ppm corresponding to the hexa and penta coordinated Al,respectively[4].The gel MKAG1also appears to have a similar structure.As the metakaolin dissolves in alkali to form a gel the environment of Al atoms undergo a change which is clearly indicated in the spectrum of MKAG2giv-ing a sharp line at$59.5(Al IV)and a small one at $6.7ppm(Al VI).The conversion of most of the Al atoms to the Al IV is indicated in the MKAG3also.This obser-vation supports the XRD results of shifting the peak max-ima towards higher2h value.The gel MKG5gives a sharp single line at59.5ppm which can be assigned to the tetra coordinated aluminium(Al IV).The most appropriate pre-nucei for zeoliteA are abundantly formed in this gel which induces fast crystal growth.Hence this gel act as the most suitable precursor for zeolite A crystallization as concluded from other observations.3.4.3.Products from various gelsProperties of products from MKAG1formed at various conditions are given in Tables3a and3b.The product having maximum crystallinity is MKA8which needs4h heating at85°C to form.Heating at higher temperatures does not give any advantage.The gel MKAG2gave a product with low crystallinity after heating for4h (MKA21and Table3c).It is interesting to see that con-ventional heating in an air oven for4h gives a product similar to MKA8.Hence,in these cases,no advantage of MW heating is achieved in the zeolite formation.The NMR studies give an explanation to this behavior.The Si and Al NMR lines of MKG1are almost the same as those of MK.In MKAG2and MKAG3,the Al line at 6.7ppm is retained even though the Si atoms are more dis-torted.These precursors are not responding to the MW heating and zeolite crystallization is not taking place.On the contrary,the MKAG5gel gives Al line at$59.5and highly distorted Si atoms which behaves as the ideal pre-cursor.The NMR spectra of MKAG4are similar to that of MKAG2,but for the more distortion of Si atoms. Hence,a combination of seeding and ageing(2h)followed by MW heating does not give a product zeolite of high crystallinity.The product with maximum crystallinity, MKA47gives silicon and aluminium lines atÀ89.5and 59.5,respectively,in their NMR spectra which are charac-teristic of zeolite A.3.5.Scanning electron microscopic studyMorphology of selected gel and product samples as examined under an electron microscope are given in Fig.9a–c(MKAG1,MKA46and MKA47).The gel sam-ples MKAG1have a morphology showing distorted pseudohexagonal platelets<1l m size as in the metakaolin [4].The material is mostlyfluffier indicating the typical gel morphology.Some cubic crystals of zeolite A along with the gel are observed in the sample MKA46(Fig.9b).The particles in thefinal product(sample MKA47)are beveled cubes and have almost uniform size(1–1.5l m)(Fig.9c).3.6.Chemical assayThe chemical analysis was carried out mainly to get the Si/Al ratio of the intermediates and the products(Table4). The Si/Al ratio of the gel formed just after mixing is0.89 and it increases slightly to1.00during crystallization.Just after mixing the metakaolin does not dissolve in the alkali and therefore the Si/Al ratio remains the same.The gel after2min MW exposure and20h ageing has almost sim-ilar Si/Al ratio of that of zeolite A.During crystallization, a small part of alumina gets leached out resulting in a higher Si/Al ratio.S.Chandrasekhar,P.N.Pramada/Microporous and Mesoporous Materials108(2008)152–161159。
雅思考试往届阅读试题华师大破解版section 1用微波来测定桥梁的damage段落很多。
主要说的是原来的桥梁损坏的检验只能人工检测。
现在一帮科学家发明了一种microwave探测仪来检验。
然后介绍了microwave探测仪具体的工作过程。
有一座大桥由于政府正好要拆除,便成了这台仪器的实验对象,科学家故意破坏了大桥的某些部位来测验仪器的有效性。
最后张望了这台机器的应用前景。
有单选题,图形题和标题对应单选题第一题问现在大桥的damage是________应该是b,固定地由人工检验第二题问microwave测量的是什么答案是有distance的那一个其他记不清了图形题较简单,对应的是文章的D段和E段。
答案是microwave dish, steel girder, flange和accelerator最后是标题对应ten years on应该对英最后一段Iapplying the knife好像是E段。
put the pressure on好像是D段how the microwave works好像是B段。
现成的试验品对应D段。
就是那个要拆的大桥Section 2厄尔尼诺现象与海鸟讲的是什么是厄尔尼诺现象,海鸟是科学家最好的研究海洋生态的实验工具,因为它的捕食能力很强。
又说今年的厄尔尼诺现象特别肆虐。
接着讲了海鸟作文实验工具的其他好处。
最后说有些人认为ALASKA的物种大量死亡是由于厄尔尼诺现象在作祟。
但是科学家Hatch认为现在下结论为时过早。
最后文章也没有明确的结论。
题目有单选题和T/F/NG单选题记不清了,但都很容易T/F/NG科学家通过海鸟的觅食可以看出当地的生物物种的健康状况。
选TRUE。
文章第一段好像最后一句话有对应。
海鸟通过发现猎物的特征来觅食。
NOT GIVEN。
文章没有寻找海洋生物可能给科学家造成困难。
选TRUE。
文章有相应的说法。
ALASKA动物和ALASKA以北的动物习性相似。
The microwave oven is an indispensable household appliance in modern life, offering convenience and efficiency in cooking and reheating food.Its invention revolutionized the way we prepare meals,allowing for quick and easy cooking options that save time and energy.History and InventionThe concept of a microwave oven was first developed in the1940s by Percy Spencer,an engineer at Raytheon.He discovered that microwaves could heat food when a chocolate bar in his pocket melted while he was working on a radarrelated project.This serendipitous event led to the development of the first microwave oven,which was large and expensive,primarily used in commercial settings.How Microwave Ovens WorkMicrowave ovens operate on the principle of dielectric heating.They generate microwaves,a form of electromagnetic radiation,which are directed at the food.These microwaves cause the water molecules in the food to vibrate,producing heat through friction.This method of heating is much faster than traditional cooking methods,as it heats the food from the inside out.Benefits of Using Microwave Ovens1.TimeSaving:Microwaves cook food rapidly,making them ideal for busy lifestyles.2.EnergyEfficient:They consume less energy compared to conventional ovens,reducing electricity bills.3.Versatility:Suitable for a variety of cooking tasks,including defrosting,reheating,and even baking.4.Cleanliness:Minimal spillage and easy cleanup,as microwaves do not require open flames or hot surfaces.Types of Microwave OvensSolo Microwaves:Designed for basic heating and cooking tasks.Combination Ovens:Incorporate both microwave and conventional oven functions, offering more cooking options.Convection Microwaves:Combine microwave technology with a fan to circulate hot air, providing a more even cooking process.Safety ConsiderationsWhile microwave ovens are generally safe to use,it is important to follow certain guidelines:Avoid using metal containers,as they can cause sparks and damage the oven. Ensure that the door seal is intact to prevent microwave leakage.Use microwavesafe materials for cooking and reheating food.Environmental ImpactMicrowave ovens have a lower carbon footprint due to their energy efficiency.They contribute to reducing energy consumption and greenhouse gas emissions,making them an environmentally friendly choice.Future of Microwave OvensWith advancements in technology,microwave ovens are becoming smarter and more integrated into smart home systems.They are expected to offer more precise cooking controls,better energy management,and integration with mobile apps for remote operation.In conclusion,the microwave oven is a testament to human ingenuity,providing a quick and efficient way to prepare meals.As technology continues to evolve,we can expect even more innovative features and capabilities from these appliances,further enhancing our cooking experiences.。
MMA-粉煤灰漂珠体系凝胶注模成型制备多孔陶瓷林晓亮;余阳;陈泉源【摘要】以甲基丙烯酸甲酯(MMA)为单体,粉煤灰漂珠为骨料,采用非水基凝胶注模成型工艺制备多孔陶瓷.考察了MMA含量对浆料性能的影响、MMA预聚合方式对浆料成型的影响以及生坯的排胶与烧结方法,并对多孔陶瓷性能进行了表征.研究表明:微波预聚合可缩短诱导期、加速MMA本体聚合;过高的微波功率和引发剂用量使反应加速,不利于聚合稳定;提高预聚合程度有助于缩短浆料固化时间、降低生坯体积收缩;为保证浆料的流动性及生坯的完整性,应将MMA预聚液含量控制在45wt%~60wt%;生坯(MMA 50wt%)在380℃排胶1h、1050℃烧结2h,得到的多孔陶瓷抗弯强度为40.35MPa,显气孔率为42.03%,平均孔径为1.12μm.%In order to avoid traditional toxic gelcasting monomer system,a nonaqueous-based gelcasting using methyl methacrylate as organic monomer and fly ash floating beads as the inorganic aggregates was adopted to prepare porous ceramics.The influences of MMA pre-polymerization method and proportion of monomers on the slurry curing were investigated,in combination with which the sintering process was also discussed.In addition,the property of the porous ceramics was characterized.The results showed that microwave pre-polymerization could shorten the induction period and accelerate the MMA bulk polymerization,while stronger microwave power and more initiator dosage could increase the reaction rate,which affect the stability of polymerization.The slurry curing time could be shortened and the volumetric shrinkage of green bodies could be reduced if the larger molecular weight prepolymer were used in thegelcasting.In order to get slurry with good fluid performance and perfect green bodies,the proportion of MMA prepolymer should be set between45wt% and 60wt%.The porous ceramics can be prepared in the conditionof the green bodies dumped at 380℃ for 1h and sintered at 1050℃ for2h.In this case,the bending strength,porosity and average pore size of the porous ceramics were 40.35MPa,42.03%and 1.12μm.【期刊名称】《材料科学与工程学报》【年(卷),期】2017(035)006【总页数】8页(P927-933,962)【关键词】凝胶注模成型;甲基丙烯酸甲酯;粉煤灰漂珠;微波预聚合;多孔陶瓷【作者】林晓亮;余阳;陈泉源【作者单位】东华大学环境科学与工程学院,国家环境保护纺织工业污染防治工程技术中心,上海201620;东华大学环境科学与工程学院,国家环境保护纺织工业污染防治工程技术中心,上海201620;东华大学环境科学与工程学院,国家环境保护纺织工业污染防治工程技术中心,上海201620【正文语种】中文【中图分类】TQ174;TB34凝胶注模成型是利用有机单体聚合将陶瓷骨料原位固定,再经由一系列固化、干燥、排胶、烧结等过程制备出致密陶瓷或多孔陶瓷材料的一种先进陶瓷制备工艺。
Microwave accelerated preparation of [bmim][HSO 4]ionic liquid:an acid catalyst for improved synthesis of coumarinsVasundhara Singha,*,Sukhbir Kaur b ,Varinder Sapehiyia a ,J.Singh b ,G.L.KadbaSchool of Chemistry and Biochemistry,Thapar Institute of Engineering and Technology,Patiala 147004,IndiabDepartment of Chemistry,Panjab University,Chandigarh 160014,IndiaReceived 5March 2004;accepted 29October 2004Available online 8December 2004AbstractA efficient and easy method for preparation of (1-butyl-3-methyl-imidazolium hydrogen sulphate)ionic liquid using sodium bisulphate in place of concentrated sulphuric acid by microwave irradiation had been developed by us with manifold reduction in time.Further,this acidic room temperature ionic liquid has been exploited for the synthesis of coumarins under microwave irra-diation and solventless conditions in short duration of time with quantitative yields,for the first time.Ó2004Elsevier B.V.All rights reserved.Keywords:Room temperature ionic liquid;Pechmann reaction;Acidic counterion;Microwave irradiation;[bmim][HSO 4](1-butyl-3-methyl-imid-azolium hydrogen sulphate)1.IntroductionDue to the environmental concerns the use of benign solvents as an alternative to volatile organic solvents are of much interest to organic chemists.The use of ionic liquids as reaction media and catalyst can offer a solu-tion to solvent emission and catalyst recycle problems [1].Ionic liquids posses the advantages like negligible va-pour pressure,reasonable thermal stability,recyclabil-ity,dissolves many organic and inorganic substrates and they are tunable to specific chemical tasks [2].Re-cently ionic liquids have been successfully employed as solvents with catalytic activity for a variety of reactions but their use as catalyst under solvent free conditions need to be given more attention [3].Ionic liquids with acidic counterions like in 1-hexyl-3-methyl-imidazolium hydrogen sulphate ([hmim][HSO 4])[4],1-butyl-3-meth-yl-imidazolium dihydogen phosphate ([bmim][H 2PO 4])[4],1-[2-(2-hydroxy-ethoxy)ethyl]-3-methyl-imidazolium hydrogen sulphate ([heemim][HSO 4])[4]and 1-butyl-3-methyl-imidazolium chloroaluminate ([bmim]Cl Æ2Al Cl 3)[5]can be used as good acid catalysts.Moreover their polar nature make them ideal for use in microwave oven.Coumarin derivatives are natural products widely distributed in the plant kingdom and their main applica-tions are as fragrances,pharmaceuticals,and agrochem-icals [6].Synthesis of coumarins has been carried out by Pechmann reaction [7],i.e.by condensation of phenols with b -ketoesters in acidic rge number of re-agents have been used for this reaction,e.g.H 2SO 4[8],HClO 4[9],P 2O 5[10]and chloroaluminate ionic liquid [5],however,these reagents are required in excess and their corrosive nature makes them difficult to handle,be-sides the formation of several side products.Literature records few papers on the microwave activation of Pech-mann reaction [11–13].We herein report,a simplified and benign procedure for the preparation of [bmim][HSO 4]using sodium bisulphate,in place of sulphuric acid [4],in a common1566-7367/$-see front matter Ó2004Elsevier B.V.All rights reserved.doi:10.1016/j.catcom.2004.10.011*Corresponding author.Tel.:+911752393303;fax:+911752364498.E-mail address:vasun7@yahoo.co.in (V.Singh)./locate/catcomCatalysis Communications 6(2005)57–60household microwave oven.The acidic nature of [bmim][HSO4]as catalyst has been exploited to promote the Pechmann reaction as shown in Scheme1.2.Experimental2.1.Preparation of[bmim][HSO4]A mixture of[bmim][Br][14](5mmol)and NaH-SO4ÆH2O(5mmol)was taken in a Borosil50ml conical flask and exposed to microwave irradiation at power le-vel1(70W)for(10+10)s.Theflask was allowed to cool and extracted with10·2ml of dichloromethane. The organic phase was decanted,dried over sodium sul-phate and solvent evaporated on rotary evaporator.The resulting viscous liquid was dried under vacuum at a pressure of0.01Torr for3h at70°C to eliminate water and obtain[bmim][HSO4]in92%yield.The anionic metathesis was confirmed for complete conversion by measuring the stoichiometric amount of sodium bro-mide formed as shown in Scheme2.2.2.Preparation of coumarins2.2.1.Preparation of coumarins under MW and thermal heatingA mixture of phenol1–5(1.0mmol)and methyl ace-toacetate(1.0mmol)was taken in a Borosil50ml beaker and to it was added[bmim][HSO4](0.12mmol).The beaker was covered with a watch glass and subjected to microwave irradiation at power level2(140W)for various time intervals(2–10min)and in case of thermal heating in a25ml round bottomflask in an oil bath at 80°C for time intervals(6–20h).The reaction mixture was allowed to cool and crushed ice was added into it. The beaker was scratched to obtain a solid,which was filtered,dried and recrystallised from ethanol to obtain coumarins in good yield and high purity.The results have been given in Table1.The spectral data and melt-ing points are in good agreement with those reported in literature[9,11].3.Results and discussionThe significant advantages of using sodium bisul-phate and microwave irradiation in the preparation of [bmim][HSO4]over the previous method is to avoid the release of corrosive hydrogen bromide and reduction in processing time from48h to20s,respectively.This room temperature ionic liquid(RTIL)formed is neat and in92%yield under microwave irradiation and solventless conditions.When the same experiment was conducted by conventional heating in the presence of 1,2-dichloroethane as solvent,it took3h for completion of reaction.The precursor[bmim][Br]used has also been prepared by microwave irradiation as reported in litera-ture[14].A catalytic quantity of the[bmim][HSO4],a bronsted acid with acidic counterion gives clean prod-ucts by the condensation of phenols and b-ketoesters in high yields(65–96%)and purity as compared to the previous methods using corrosive H2SO4.The reaction has been carried out both by thermal heating and micro-wave irradiation as shown in Table1.The optimization of the process by varying temperature,time and catalyst loading was done to get products in high yields and pur-ity.The yields of the products obtained by microwave irradiation verses thermal heating are higher with remarkable reduction in reaction time due to homoge-neous heating(as a result of strong agitation of reactant molecules)throughout the reaction media by microwave irradiation as compared to convection currents in ther-mal heating.This methodology avoids the use of corro-sive acids,solvents and requires only catalytic amount of the ionic liquid to promote the reaction.4.ConclusionIn conclusion,this preliminary work demonstrates the potential application of ionic liquids with acidic counterions as good acid catalysts in synthesis of hetero-cyclic compounds of biological importance.Further studies of few more ionic liquids with acidic counterions for promoting several other acid catalyzed reactions due their good catalytic activity,efficiency and green nature are underway.58V.Singh et al./Catalysis Communications6(2005)57–60AcknowledgementsThe authors are grateful to Department of Science and Technology(DST),New Delhi and CSIR(S.K.) for thefinancial support provided.References[1](a)T.Welton,Chem.Rev.99(1999)2071;(b)R.Sheldon,mun.(2001)2399.[2]J.Kwan,M.-J.Kim,.Chem.67(2002)6845.[3]T.-S.Li,Z.-H.Zhang,F.Yang,C.-G.Fu,J.Chem.Res.1(1998)38.[4]J.Fraga-Dubreuil,K.Bourahla,M.Rahmouni,J.P.Bazureau,J.Hamelin,mun.3(2002)185.[5]M.K.Potdar,S.S.Mohile,M.M.Salunkhe,Tetrahedron Lett.42(2001)9285.[6]R.OÕKennedy,R.D.Thornes,Coumarins;Biology,Applicationsand Mode of Action,Wiley,Chichester,1997.[7]H.V.Pechmann,C.Duisberg,Ber.16(1883)2119.[8]H.V.Pechmann,C.Duisberg,Ber.17(1884)929.[9]M.Bulut,C.Erk,Dyes Pigments30(1996)99.[10]A.Robertson,W.F.Sandrock,C.B.Henery,J.Chem.Soc.(1931)2426.[11]V.Singh,J.Singh,K.Kaur,G.L.Kad,J.Chem.Res.(1996)58.[12]S.Frere,V.Thiery,T.Besson,Tetrahedron Lett.42(2001)997.[13]J.Singh,J.Kaur,S.Nayyar,G.L.Kad,J.Chem.Res.(1998)280.[14]R.S.Varma,V.V.Namboodiri,mun.(2001)643.60V.Singh et al./Catalysis Communications6(2005)57–60。