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1+x初级云计算考试模拟题（附答案）一、单选题（共60题，每题1分，共60分）1、下列选项中哪个不是软件需求规格目标?A、便于软件维护B、控制系统的实施过程C、便于用户.分析员和软件设计人员进行理解及交流D、作为软件测试和验收以及维护的依据正确答案：A2、SQL线程通过读取______文件中的日志,并解析成具体操作,来实现主从的操作一致,最终达到数据一致。
A、i/o logB、binlogC、relay logD、sql log正确答案：C3、下面关于ADocker Image说法错误的是?A、镜像是一个只读模板B、由Dockerfile文本描述镜像的内容C、镜像定义类似面向用户的类D、构建一个镜像实际就是安装.配置和运行的过程正确答案：C4、Amazon SWF中的SWF代表什么?A、简单的工作流程B、简单的工作流程形成C、简单的Web表单D、简单的工作自动化正确答案：A5、下面哪个说法是正确的。
A、重新开发一个新系统通常要比再工程的成本要低B、只有质量差的软件产品才需要维护C、软件的不断修改将导致系统结构的恶化D、软件的维护成本通常比开发成本低正确答案：C6、以下Cinder命令可以查询云硬盘列表的是?A、cinder volume listB、cinder volume showC、cinder showD、cinder list正确答案：D7、Docker制作镜像的时候,通常使用以下哪种方式来构建A、DockerfileB、Docker composeC、Docker SwarmD、Docker Machine正确答案：A8、读写分离中以下哪个是从库负责的功能?A、查B、增C、删D、改正确答案：A9、下面哪个用户用于存放用户密码信息?A、/varB、/etcC、/devD、/boot正确答案：B10、您可以向一个帐户添加多少个S3存储桶?A、100B、默认为100,但是可以通过联系AWS来增加。
ApacheLogsViewer5.46安装使⽤记录（apache⽇志分析⼯
具）
【安装】
1、先安装“ApacheLogsViewer.exe”
2、在C:\Windows\System32\drivers\etc\hosts⽂件中添加： 127.0.0.1
3、运⾏软件，输⼊以下任意⼀组解锁码即可。
【特别注意】
上边必须先执⾏第2步，再执⾏第3步，否则会激活失败。
假如出现激活失败的情况下，请删除“C:\Users\Administrator\AppData\Roaming\apachelogsview\*.chk”⽂件，然后
确保第2步执⾏好的前提下重新输⼊解锁码。
【⼀些配置】
Edit Preferences
Columns可以勾选需要显⽰的字段
Geolocation是ip地理查询
放⼊程序安装⽬录和下⾯⽬录：
C:\Users\Admin\AppData\Roaming\apachelogsview
重启软件
⽐较看中的是它的筛选功能
例如status是error的，选择之后点击Include，再点Apply Filter筛选：
还有⾃定义⽇志规则：
分析⽇志⽅便很多，通过筛选查找异常数据，追踪⼊侵者变得简单了许多。
apache工具类常用方法
Apache Commons是一组开源工具库，提供了一些实用的方法和工具类，用于简化常见的编程任务。
以下是Apache Commons工具类中一些常用
的方法：
1. Apache Commons Lang：提供了一些用于处理Java基本类型的实用方法，例如字符串操作、数字格式化、数组操作等。
2. Apache Commons IO：提供了一些用于处理文件和IO操作的实用方法，例如文件操作、文件过滤、文件复制等。
3. Apache Commons Collections：提供了一些用于处理集合的实用方法，例如集合转换、集合过滤、集合映射等。
4. Apache Commons Math：提供了一些用于数学计算的实用方法，例如
数学函数、线性代数、统计计算等。
5. Apache Commons Validator：提供了一些用于数据验证的实用方法，
例如字符串验证、电子邮件验证、IP地址验证等。
这些工具类中的方法都是静态的，可以直接通过类名调用，无需创建对象实例。
使用这些工具类可以大大简化代码，提高开发效率。
我和我的家人假期作文英文回答：During the vacation, my family and I had a wonderful time together. We decided to go on a road trip to explore different cities and experience new adventures. It was a great opportunity for us to bond and create lasting memories.Firstly, we visited New York City. The bustling streets, towering skyscrapers, and vibrant atmosphere captivated us. We took a stroll in Central Park, visited the iconic Times Square, and enjoyed a Broadway show. The city's energy was contagious, and we couldn't help but immerse ourselves in the hustle and bustle.Next, we headed to Los Angeles, California. The sunny weather and palm trees welcomed us as we explored the famous Hollywood Walk of Fame. We also visited Universal Studios and had a blast on the thrilling rides. Thehighlight of our trip was a visit to the Griffith Observatory, where we witnessed a stunning sunset over the city.Afterwards, we made our way to Las Vegas, Nevada. The dazzling lights and extravagant hotels amazed us. We tried our luck at the casinos and watched incredible live performances. The city never slept, and there was always something exciting happening around every corner.Moving on, we ventured to San Francisco. The iconic Golden Gate Bridge and the charming streets of Chinatown left a lasting impression on us. We took a ferry to Alcatraz Island and learned about its fascinating history. The city's hilly landscape provided breathtaking views, especially from the top of Twin Peaks.Finally, we concluded our trip in Miami, Florida. The beautiful beaches and crystal-clear waters were perfect for relaxation. We indulged in delicious seafood and enjoyed water sports such as snorkeling and jet skiing. The vibrant nightlife of South Beach added a touch of excitement to ourvacation.中文回答：在假期期间，我和我的家人度过了愉快的时光。
Apache日志轮询使用cronolog和webalizer分割和分析apache日志web服务器的日志对于网站管理者来说有非常重要的作用，对于分析网站的访问情况、搜索引擎的抓取、图片盗链、非法抓取等有很大的帮助。
目前apache是最为广泛应用的web服务器，apache的日志功能能通过访问日志可以比较详细的记录网站服务器的被请求情况，但是要更好的根据日志来维护和管理网站则需要其他的工具来分析日志，以生成便于查看的报表。
默认安装的apache在运行时会产生两个日志文件，access_log用于存放访问记录，error则存放出错记录。
日志的生成格式可以定制的，需要在配置文件中定义LogFormat "%h %l %u %t \"%r\" %>s %b" commonCustomLog logs/access_log common上面的配置是最常用的一种记录格式，产生的日志格式如下：127.0.0.1 - - [02/Jan/2007:19:41:07 +0800] "GET /themes/original/img/s_error.png HTTP/1.1" 200 272这是一条典型的apache访问记录，这条记录里面包含有远程访问IP( 127.0.0.1 )、访问者身份（现在一般缺省，以-代替）、访问者标识（缺省以-代替）、请求时间(02/Jan/2007:19:41:07 +0800)、请求方式(GET)、请求的协议(HTTP/1.1)、请求的资源(/themes/original/img/s_error.png)、响应情况(200，代表成功)、传输的字节数(272)。
还有一种比较常用的格式LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" combined CustomLog log/access_log combined127.0.0.1 - - [02/Jan/2007:19:41:07 +0800] "GET /themes/original/img/s_error.png HTTP/1.1" 200 272"" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.1) Gecko/20061208 Firefox/2.0.0.1"Referer标示记录下来源，User-Agent则会记录客户端浏览器提供的一些识别信息，比如操作系统类别、浏览器类型和版本等，当然也可能是爬虫的信息。
华为HCNP-云运维资深工程师认证考试题库（A）1 通常说灾备是将容灾与备份结合，既本地备份结合远程数据复制实现完善的数据保护。
（）A 对B 错2 ServiceCenter(SC，运营中心)支持部署在FusionSphere OpenStack虚拟化环境中的虚拟机上，支持主备部署和单节点部署。
（）A 对B 错3 ServiceCenter可以通过多少个KeyStone对接非级联FusionSphere资源池？（）A 1B 2C 5D 104 使用ISO镜像创建虚拟机时，规格中的启动源只能是本地磁盘，根磁盘的大小为0，临时磁盘大小等于系统盘的大小。
（）A 对B 错5 虚拟机通讯如何能够绕过网络安全控制措施？（）A 大多网络安全系统无法识别加密的虚机流量B 同一台服务器内部的虚拟机通信对物理安全设备不可见C 虚机镜像可能包含绕开防火墙的工具D 客户操作系统可以激活秘密模式6 TCP/IP V4版本，存在的安全隐患包括哪些？（）A 缺乏数据源验证机制B 缺乏对数据包的确认机制C 缺乏对数据完整性的验证机制D 缺乏机密性保障机制7 在OC上可以监控虚拟机的告警（）A 对B 错8 关于虚拟机VNC登录的描述，哪个选项是错误的？（）A “TightVNC”模式整体依赖Java(TM)插件运行B “noVNC”模式不依赖Java(TM)插件，但无法对虚拟机进行重启，关闭等操作C 64位浏览器可以运行32位的Java(TM)插件D “noVNC”模式的光驱管理功能也需要依赖Java平台9 IPSec中使用AH+ESP方式建立一个IPSec隧道，会建立几个IPSec SA（安全联盟）?（）A 2B 3C 4D 110 eSight（监控软件）本地高可用（一主一备）系统包括主服务器，每个服务器由一台服务器组成。
（）A 对B 错11 清理ManageOne OC磁盘时，下列哪个目录文件可以清理（临时数据可以清理）？（）A /opt/OperationCenter/AppBase/OC/AppBast/var/iemp/data/dump/B /opt/OperationCenter/AppBase/OC/APPBase/var/iemp/logC /opt/Operation/Center/AppBase/OC/AppBase/etc/D /opt/OperaCenter/AppBase/DB/data12 FusionCompute的分布式交换机功能类似于二层物理交换机，通过下列哪些选项连接虚拟机和物理网络？（）A 端口组B VLAN池和子网C 上行链路组D 下行链路组13 关于不同模式下的IT服务组织，描述错误的是哪项？（）A 传统模式下的IT服务组织是内部IT供应商B 私有云模式下的IT服务组织是共享服务单元C 私有云模式下的IT服务组织是内部IT供应商D 公有云模式下的IT服务组织是外部供应商14 假设环境中每台主机拥有4颗8核的物理CPU，总物理核数为32个，一个虚拟机设置了CPU插槽数量为4，CPU数量为8个，下列哪个选项是正确的分配方式？（）A 由主机上一个物理CPU的8个核组成虚拟机的8个虚拟CPUB 一个物理CPU提供5个内核，另一个物理CPU提供3个内核C 一个物理CPU提供4个内核，另外一个CPU提供4个内核D 虚拟机的8个CPU平均由主机上的4个物理CPU提供，每个物理CPU提供2个内核15 云计算服务交付模式主要有IaaS，PaaS和SaaS（）A 对B 错16 eSight为方便用户使用存储资源分配特性，特别设计了使用模板进行资源批量配置和批量回收（）A 对B 错17 以下哪个选项不属于FusionCompute的存储设备？（）A LUNB 本地设备C Advanced SAN存储池或FusionStorge存储池D 本地内存盘18 关于块存储和对象存储的描述错误的是哪个选项？（）A 块存储Cinder是给虚拟机挂载使用，向虚拟机提供额外的磁盘空间B 对象存储Swift存放虚拟机镜像C 在FusionSphere环境中，Giance后端存储默认为Swift对象存储D 在FusionCompute环境中，块存储只包括SAN存储，本地存储19 eSight服务硬盘信息监控不包括的指标是哪个？（）A 硬盘名称B 健康状态C 在位信息D 硬盘利用率20 安装ManagOne SC和OC选择的操作系统是下列哪个选项？（）A CentOSB RadHat LinuxC Windows ServerD SUSE Linux21 关于eSight单机系统软件步骤，描述错误的是以下哪一项？（）A 手动安装操作系统B 手动安装MySQL数据库C 手动安装防病毒软件D 执行安全加固22 入侵防御系统技术特点包括哪些？（）A 在线模式B 实时阻断C 自学习自适应D 直路部署23 关于事件中的升级，我们可以把它分为哪些类型？（）A 技术升级B 服务升级C 管理升级D 混合升级24 eSight单机虚拟化部署支持以下哪些虚拟资源？（）A FusionSphere 5.1B FusionSphere 6.0C VMWare ESXI 5.5D Microsoft Hyper-V25 FusionSphere支持的工具不包含下列哪个选项？（）A FusionCubeB Update toolC FusionCareD WEB-UI26 以下关于FusionSphere Opentack OM资源池配置的描述中，哪个选项是错误的？（）A 创建主机组时，首先指定主机组所属的可用分区，并从该可用分区中选择若干主机，组成主机组B 如果对接FusionCompute，可用分区需要和接入FusionCompute存储集群中设置的“可用分区”保持一致C 外部网络是用于连接系统外网络的网络，但不能是InternetD “fc-nove-computeXXX”实际为FusionSphere OpenStack上一个接入的一组FusionCompute计算集群27 ManagOne OC的日常维护包括哪几项？（）A 软件许可导入B 检查日志C 检查服务器运行状态D 检查单机和双机状态E 检查告警28 常见的数据迁移方案包括以下哪些类型？（）A LVM镜像迁移方案B Rsync迁移方案C Datasync迁移方案D vMotion迁移方案29 下列哪项服务不是PaaS提供的服务？（）A 中间件B 数据库C 安全D 开发工具30 OpenStack的管理数据支持备份，保障系统高可靠性，主要的备份方式有哪些？（）A 共享存储备份B 管理系统无单故障，采取ZooKeeper/Paxos 3节点负荷分组方式高可靠部署，任意一个节点故障都不会影响系统功能C 服务器本地存储双分区D 自动备份管理数据并传输（FTP/S3/HTTPS）到第三方存储设备31 eSight拓扑管理功能包括以下哪项？（）A 设备拓扑B 告警跳转C 设备离线展示D 网元管理器跳转32 在安装和部署FusionCompute时，我们可以配置CNA的VLAN信息，但是不能配置VRM （管理节点）的VLAN信息（）A 对B 错33 外部服务提供商的业务关系管理通常是由一个单独的BRMs的专用职能或客户经理执行。
本教程是在笔者学习JNDI过程中，由于没有合适的免费服务器做为实验，给Sun的JNDI 教程的LDAP服务器使用的又是Sun的服务器，OpenLDAP又没有找到Windows的版本，所以就决定使用Apache的开源LDAP服务器---Apache Directory Server。
下面是Apache 网站对Apache Directory Project的介绍：The Apache Directory Project provides directory solutions entirely written in Java. These include a directory server, which has been certified as LDAP v3 compliant by the Open Group (Apache Directory Server), and Eclipse-based directory tools (Apache Directory Studio).Apache Directory项目提供了用纯Java编写的目录解决方案，其中包含ApacheDS，即Apache Directory Server，它是一个被授权的LDAP v3的服务器。
同时还包含基于Eclipse 的目录工具，即Apache Directory Studio。
ApacheDS基本用户参考指南，主要介绍了如何安装ApacheDS 1.0，通过不同的图形化客户端连接服务器，当然主要还是需要通过JNDI编程来实现服务器的连接，这部分内容在JNDI教程中进行介绍。
同时介绍了如何操作目录服务中的数据以及将ApacheDS和其它软件进行集成。
Apache Directory Server简介ApacheDS 1.0是一个由纯Java语言编写的开源LDAP服务器。
ApacheDS具有可嵌入、可扩展、标准的遵守LDAP协议等特性，同时支持其他的网络协议，例如NTP和Kerberos。
1. ASTRONOMY天文学astronomical 天文的astronomical observatory 天文台astronomical instruments 天文仪器astronomical telescope 天文望远镜astronomical observation 天文观测astronomical unit 天文单位astronomical almanac (yearbook) 天文年历planetarium 天文馆astronomer 天文学家astrophysics 天文物理学astrophysicist 天文物理学家astro photo graph 天体摄影影图astrology 占星学pseudoscience 伪科学hidebound 包紧的；思想狭隘的pinnacle(peak; summit; apex) 巅；顶峰infinite 无限的cosmic 宇宙的cosmic force 宇宙力cosmic dust 宇宙尘cosmic noise 宇宙噪声cosmic radiation 宇宙辐射cosmic rays 宇宙射线cosmic speed 宇宙速度celestial 天的celestial body (heavenly body) 天体celestial map (sky atlas) 天体团celestial sphere 天球celestial globe 天球仪terrestrial … 地球仪celestial mechanics 天体力学celestial navigation (astronavigation)天文导航stellar 星的nebula (复数nebulae 或nebulas) 星云nebular(nebulous)星云的；星云状的dwarf (dwarf star) 矮星quasar 类星体；类星射电源constellation 星座planisphere 平面天球图,星座图cluster 星团solar 太阳的solar system 太阳系solar corona 日冕solar flare 日辉；太阳耀斑solar prominence 日珥solar eclipse 日食solar radiation 太阳辐射planet 行星planetoid (asteroid) 小行星revolve 旋转；绕转twinkle 闪烁naked eye 肉眼Mercury 水星Venus 金星Earth 地球Mars 火星Jupiter 木星Saturn 土星Uranus 天王星Neptune 海王星Pluto 冥王星orbit 轨道spin 旋转satellite 卫星lunar 月球的lunar eclipse 月蚀lunar probe 月球探测器lunar astronaut (lunarnaut) 登月宇航员lunar excursion module登月舱lunar rover (lunar roving vehicle; moonrover) 月面车lunarscape (moonscape) 月面景色phase 月相；阶段meteor 流星meteor shower 流星雨meteoroid 流星体meteorite 陨石space capsule 宇宙飞船座舱；航天舱spacelab 太空实验室spaceman (astronaut; cosmonaut) 宇航员；航天员space suit 宇航服；航天服space shuttle 航天飞机space telescope 空间望远镜2. GEOGRAPHY地理geographer 地理学家hemisphere 半球northern and southern hemispheres 北半球和南半球eastern and western hemispheres 东半球和西半球meridian 子午线；经线parallel 平行圈；纬线latitude 纬度high latitudes 高纬度地区low latitudes 低纬度地区temperate latitudes 温带地区longitude 经度horizon 地平线equator 赤道Tropics 热带地区Arctic 北极Antarctic (Antarctica) 南极expedition 探险zone气候带plateau (highland) 高地lowland 低地basin 盆地cavern (cave) 洞穴terrain 地域subterranean (underground) 地底下coastland 沿海地区island 岛屿continental island 地陆岛volcanovolcanic island 火山岛… eruptioncoral island 珊瑚岛islet 小岛peninsular 半岛continent 大陆continental shelf 大陆架ranges 山脉valley 峡谷canyon (谷底有溪涧流过的)峡谷海峡altitude 高度remote-sensing 遥感的terrestrial 地球的；陆地的globeterrestrial heat (geothermal; heat of theearth’s interior) 地热terrestrial magnetism地磁(geomagnetism) 地磁3.GEOLOGY地质学geologist (geologician) 地质学家geological (geologic) 地质学的geologic age (geological time) 地质时代geologic map 地质图geological survey地质调查continental crust 大陆地壳oceanic crust 海洋地壳layer (stratum; 复数strata) 地层mantle 地幔core 地核plate 板块plate tectonics 板块构造论fault 断层fault plane 断层面fault zone 断层带rift (crack; split)断裂disintegration (decomposition)分解erosion侵蚀fossil化石rock 岩石igneous rock火成岩sedimentary rock沉积岩metamorphic rock变质岩quartz石英limestone石灰岩marble大理石granite花岗岩lithogenqus岩石成的lithosphere岩石圈1word版本可编辑.欢迎下载支持.magma岩浆prospect勘探sounding测探mine采矿mineral矿物ore矿石deposit矿床platinum白金；铂copper黄铜aluminum铝tin锡lead铅unleadedzine锌nickel镍mercury (quicksilver)汞；水银gem宝石diamond钻石emerald绿宝石glacial epoch (age, period)冰川期glacial drift冰碛iceberg冰山(ice)sheet 冰原；冰盖frigid(refrigerated; freezing)寒冷的plummet (气温)急剧下降thaw (melt) 融化retreat后退extinct volcano死火山dormant volcano休眠火山eruption火山喷发crater火山口lava火山岩浆scoria火山渣volcanic火山的volcanic dust火山尘volcanic ash火山灰magnitude震级epicenter震中hypocenter (focus)震源(earthquake; seismic; shock)wave地震波cataclysm灾变4. ECOLOGY 生态学ecological 生态的ecological condition生态环境ecological disaster生态祸害ecosphere(biosphere)生态圈ecocide生态灭绝preservation（对自然区等的）保护fauna 动物群flora植物群rain forest雨林afforestation 植树造林environmental pollution环境污染environmental protection环境保护environmental sanitation环境卫生(environmental)sanitary engineers环卫工人（工程师）environmentalist环境保护主义者acid rain 酸雨greenhouse effect温室效应infrared radiation 红外线辐射ozone layer (ozonosphere)臭氧层紫外线辐射污染控制air pollution空气控制pollution elimination污染消除pollution index污染指数pollution indication organism污染指示生物air pollution空气污染water pollution水污染noise pollution噪音污染soil pollution土壤污染pollution-free无污染pollutant污染物noxious (toxic)有毒的fumes(有毒)废气waste废物waste heat废热waste water废水solid waste固体垃圾sewage(wastewater)污水domestic sewage生活污水sewage purification污水净化sewage disposal污水处理sewage plant污水处理工厂decibel（噪音）分贝abate (reduce) 减少abound 大量存在补充：air monitoring空气监测air pollution空气污染alternative n.二中择一, 可供选择的办法,事物adj.选择性的, 二中择一的atmosphere 大气, 空气, 气氛balance (of nature) 自然界生态平衡burning of coal and oil 煤油燃烧carbon 碳, (一张)复写纸carbon dioxide release二氧化碳排放dioxide 二氧化物clean up 清除干净climate 气候, 风土, 思潮climatic change长期的气候变化coal .煤v.加煤coalification煤化deforest滥伐森林desertification沙漠化deteriorate 恶化disposal废物处理drought干旱ecologist 生态学家ecosystem 生态系统el Niño厄尔尼诺现象emission(汽车废气的)排放energy conservation保护能源energy source 能源资源solar energy太阳能tidal energy潮汐能fuel-efficient节能型的nonrenewable不可再生的Environmental Awareness Clubexhaust fumes废气fauna 动物群flora 植物群food chain食物链flood洪水fossil fuel 矿物燃料fuel-efficient节能型的fumes （有毒）废气garbage垃圾, 废物gas 气体, 煤气, 毒气, 汽油, [矿]瓦斯global warminggreenhouse effect 温室效应ice-cap 冰帽industrial sewage工业污水infrared radiation 红外线辐射litter/trash garbage垃圾long-term climatic change长期的气候变化melt 融化noise pollution 噪音污染non-renewable 不可更新的noxious (toxic) 有毒的offshore spillage 近海岸溢出ozone layer (ozonosphere) 臭氧层pollute/pollutant 污染物pollution control 污染控制pollution污染pollution-free 无污染preservation 保存process of photo synthesis光合作用purify净化rain forest 雨林recycle回收利用recycling center再循环利用中心recycling再循环resource 能源rise in sea level 海平面上升rush hour 高峰期sewage (wastewater) 污水sewage disposal污水处理sewage purification 污水净化sewage污水soil pollution 土壤污染solar energy太阳能solid waste固体废物soot烟尘tidal energy潮汐能traffic jam交通堵塞trash bag垃圾袋ultraviolet radiation 紫外线辐射upper atmosphere上层大气2word版本可编辑.欢迎下载支持.waste 废物wastewater废水water pollution 水污染water shortage 水源缺乏wildness 野生/天然zero emission 零辐射species物种specimen 样本，标本natural selection自然选择biological vacuum生物演变真空期survival生存thwart (block; obstruct)阻碍reverse逆向；倒退degeneration (devolution) 退化alga(复数algae)藻类invertebrate无脊椎动物aquatic (life)水生动物reptile爬行动物amphibian(amphibious animal)两栖动物dinosaur恐龙bird鸟类extinction灭绝mammal哺乳动物primates灵长目动物class 纲order 目family 科genus 属suborder 亚目species 种insect 昆虫antenna (复数antennae) 触须larva 幼虫，幼体camouflage 伪装pest 害虫worm 虫，蠕虫hibernate 冬眠lizard 蜥蜴chameleon 变色蜥蜴regeneration 再生turtle 龟beast 野兽domesticate 驯养predatory (carnivorous ) 食肉的predator 捕食者prey （动词）捕食（名词）被捕食的动物scavenger 食腐动物migrate 迁移wing 翅膀，翼bill （鸟）嘴beak （鹰等的）嘴nest 筑巢dolphin 海豚whale 鲸鱼bat 蝙蝠gorilla 大猩猩chimpanzee 黑猩猩habitat 栖息地rodent 啮齿动物（如松鼠）primate 灵长动物plankton 浮游生物mollusk 软件动物coelenterate 腔肠动物（如珊瑚）shrimp 小虾prawn 对虾lobster 对虾crab 螃蟹clam 蛤蜊sponge 海绵coral 珊瑚starfish 海星canary 金丝雀chirp (鸟，虫的叫声)唧唧squeak （老鼠等）吱吱porpoise 海豚sloth 树懒slothful 懒惰的hygiene 卫生sanitation 卫生parasite 寄生虫moth 蛾caterpillar 毛虫hordes (昆虫等)群swarms (昆虫等)群flock （鸟，羊等）群herd 兽群bunch （花等）束，捧beaver 海狸community 动物的群落或人的部落monogamous 一夫一妻的polygamous一夫多妻的，一雄多雌的polyandrous 一妻多夫的，一雌多雄的trapper 诱捕动物者rhinoceros 犀牛niche 小生态环境vestige 退化器官，遗迹oyster 牡蛎fertilizer 使…受精larvae 幼虫tentacle 触角homotherm 恒温动物poikilotherm 变温动物metabolism 新陈代谢baboon 狒狒breed (名词)品种，（动词）繁殖multiply （reproduce）繁殖hatch 孵spawn (鱼、虾、蛙等)孵offspring (young) 解剖学anatomy 解剖学appetite 食欲creature 生物microbe 微生物herbivorous 食草的carnivorous 食肉的杂食的antennae)触须compound eye复眼thorax 胸部wing翅膀larva幼虫；幼体camouflage伪装beneficial有益的pest害虫pesticideworm虫；蠕虫flatworm扁虫（低等蠕虫）roundworm蛔虫；线虫segmented (worm)分节的adder小毒蛇rattlesnake响尾蛇cobra眼镜蛇venom毒液fang毒牙molt蜕皮coil盘绕caterpillarregeneration再生crocodile鳄鱼alligator美洲鳄驯养domesticationpre’datory (carnivorous) 食肉的prey（动词）捕食；（名词）被捕食的动物scavenger食腐动物falcon隼migrate迁移wing翅膀；翼bill（鸟）嘴beak（鹰等的）嘴nest筑巢nestleperch（鸟）飞落；暂栖flock to habitatmolt （鸟）脱羽毛dolphin海豚whale鲸鱼bat蝙蝠chimpanzee黑猩猩baboonprimitive(men)原始的civilized (men)文明的diversity品种多样gregarious (social)群居的habitat栖息地breed（名词）品种；（动物）繁殖reproduce繁殖, 复制, 使...在脑海中重现multiply (reproduce)繁殖mating交配hatch孵spawn（鱼、蛙等）产卵后代botanical (botanic) 植物的3word版本可编辑.欢迎下载支持.plant植物seed plant种子植物garden plant园艺植物…ing toolstropical plant热带植物grassland plant草原植物tundra plant冻原植物desert plant沙漠植物alpine plant高山植物marsh plant沼泽植物aquatic plant水生植物parasitic plant寄生植物host plant root 根stemmeshwork网状结构canopy树冠层；顶蓬foliage (leaf)叶leaflet小叶rosette(叶的)丛生stem茎stalk杆leafstalk叶柄shoot (sprout)嫩芽；抽枝flower花bud花蕾blossompetal花瓣wilt, fade 枯萎，凋谢flesh果肉stone果核core果心kernel果仁peel (skin)果皮shell (硬)果壳husk (干)果壳；（玉米）苞叶trunk树干branch树枝bough大或粗树枝twig小树枝bark树皮jungle丛林blade (of grass) 一片草叶tuft一丛草lawn草坪meadow草地；牧场prairie 大草原shrub (bush)灌木cluster 一簇（灌木）vine藤liana藤本植物fern蕨类植物herb芳草herbal teaphotosynthesis光合作用symbiosis共生autotrophic自养的heterotrophic异养的wither (shrivel; fade)凋谢wiltdieback顶死；回枯pollen花粉pollinate传授花粉pollination传粉；已授粉状态bacterium(pl.bacteria)细菌disinfection消毒enzymes酵母fermentation发酵inflection传染(感染)microbe微生物microorganism微生物sterilization灭菌toxin毒素氨基酸carbohydrate 碳水化合物carbon dioxide二氧化碳glucose 葡萄糖organism 有机物oxidation氧化protein 蛋白质civilized文明的brute-like野蛮的community社区；社会organization(association)组织institution 机构settlement定居；居民点custom风俗习惯incumbent 现任monarchy君主制abhorrence憎恶；讨厌empire帝国anarchism无政府主义federal system联邦制presidential system总统制Congress美国国会House of Senate 参议院ethnic(racial)种族的ethic 道德的poll民意调查pollster民意调查人questionnaire问题单；调查表respondent民意调查对象census人口调查（普查）protocol（外交）礼节courtesy有礼貌的举止manners (conduct)举止；礼貌office manners办公室礼仪solitude孤独isolationcompanion伙伴sociable善于交际ethics(morality)道德observe(abide by)遵守violate(breach)违反；破坏报答富裕的poverty贫困inequality不平等discontent不满grumbling(complaint)抱怨enmity(hatred) 仇视slander污蔑libel诽谤rebellion 反叛conflict(clash)冲突crash=collidediscord(disagreement)不和harmony和睦stability稳定交通与通信traffic signal 交通信号traffic marking 交通（道路）标线traffic regulation 交通规则traffic emergency 交通紧急情况traffic congestion(jam) 交通阻塞transport (动词)运输transportation (名词)运输；运输工具vehicle 交通工具；车辆prototype 原型wagon(carriage) 马车；篷车vessel 船；容器automobile (auto; car) 汽车taxicab (cab; taxi) 出租汽车bus 公共汽车truck 卡车van 运货车motorcycle 摩托车bicycle (bike) 自行车pedal 脚蹬；踏板handbar 车把gear 齿轮；（排）档engine 引擎；发动机gasoline engine 汽油发动机diesel engine 柴油发动机internal combustion 内燃cylinder 汽缸piston 活塞tank 油箱lubrication 润滑brake （名词）闸；（动词）刹车exhaust （名词和动词）排气emission 散发；排出（动词emit）fume 废气assemble 装配4word版本可编辑.欢迎下载支持.service (maintenance) 维修mechanic 机修工garage 车库license 执照parking 执照parking停车parking lot停车场（收费机）toll通行费driveway私人车道interchange交换道cloverleaf四叶式立体交叉intersection道路交叉口lane车道avenue(thoroughfare) 马路；街passenger 乘客crosswalk（穿马路）人行横道sidewalk（马路旁）人行道subterranean(underground)地底下platform站台locomotive火车头switch扳道；道岔car车厢commuter（来往于市郊之间）旅客haul拖；拉；运送freight 货物；货运container集装箱subway 地铁token专用辅币turnstile旋转栅门canoe 独木舟ship船；舰sailing航海；张帆航行Viking 斯堪的纳维亚人；北欧海盗cargo 货物barge驳船tanker油船steamboat汽船；轮船ocean liner远洋轮submarine潜水艇ferry渡船oar桨paddle（名词）短浆；（动词）用桨划row划船steer掌舵；驾驶bow(prow)船首stern船尾port左舷starboard右舷deck甲板on board(aboard)在船上；在汽车、火车、飞机上navigate航行（海、河、空中）log航海日志wreck沉船；残骸supersonic超音速jet喷气式飞机jet lag时差综合症runway机场跑道pilot飞行员crew全体机务人员；全体船员helicopter直升飞机vertical垂直的rotor旋翼hover空中盘旋rescue营救inaccessible难以到达（进入）的compass 指南针aeronautical航空的gesture手势printing印刷postal邮政的postage邮资postmark盖邮戳telegraph电报code密码decode 解密transmitter发报机cable电缆telephone(phone)电话telephone exchange电话局pager (beeper)拷机；BP机handset耳机；听筒dial拨电话operator接线员phonograph 留声机digital数字的；数字显示式videotape录像带telex电传broadcasting电台广播frequency频率entertainment娱乐dis jockey (DJ)音乐唱片节目播音员newscast新闻节目talk show访谈节目host (访谈)节目主持人；（女主持人hostess）announcer节目报告员；时事评论员；比赛讲解员walkie-talkie步话机remote control遥控studio播音室；演播室soundproof隔音control panel控制盘收费电视closed-circuit television闭路电视direct——broadcastsatellite(DBS)system卫星直播telecast (动词)电视广播；（名词）电视广播节目live现场直播relay转播zoom（可变焦距镜头）推近或拉远piecemeal零碎地；一个个地screen屏幕antenna天线confines(boundary)限制；边界linger延续；逗留8. PSYCHOLOGY心理学applied psychology应用心理学psychologist心理学家psychiatrist 精神病医师, 精神病学家psychological心理的psychological test心理测试psychological moment心理最佳时刻psychological warfare心理战psychotherapy 心理疗法conformity 一致；符合；从众majority 多数人mental 精神的minority 少数人physical 躯体的，物质的，物理的mental 心理的spiritual 精神的；心灵的subject受实验物件；学科threshold judgment （心理学）初始性behavioral pattern行为模式deportment (demeanor)行为举止；风度factor因素elementcause起因aspect方面motive动机modify (动词)矫正；修改negative displacementpositive …modification (名词)矫正overt 公开的extrovertedcovert 隐蔽的introverted 内向的, 含蓄的, 闭关自守的learning学习cognitive认识过程的；认识能力的empirical经验的；以经验为依据的conditioning条件作用association联想；观念的联合retarded智力迟钝的intelligence quotient (IQ)智商arithmetic 算术, 算法mental age智力年龄；心理年龄chronological age实龄chronicle .编年史v.编入编年史voluntary 自愿的5word版本可编辑.欢迎下载支持.6word 版本可编辑.欢迎下载支持.involuntary 本能的；非自愿的 behaviorism 行为主义；行为主义心理学派unconscious 潜意识的 subconscious 下意识； instinct 本能psychiatric 精神病学的 mentally ill 精神疾患mental disorder 心理紊乱（失调） (psychopathology)变态心理学 耶洗别 jezebel 无耻放荡的女人，恶毒的女人 irrational 不合情理的 neuro-sis 神经机能病neurotic 神经官能症患者psychosis 神经错乱 psychotic 患精神病的insane(mad; lunatic)精神失常insane asylum(mental hospital)精神病院 flying over cockoo’s nest delusion 妄想；错觉 hysteria 歇斯底里；癔病 phobia 恐惧症 mania 狂躁paranoia 妄想；多疑 diffusion of responsibility9. PHYSIOLOGY 生理学physiologist 生理学家anatomy 解剖学；人体结构autopsy (postmortem examination)（尸体）解剖dissect (anatomize)解剖 scalpel 解剖刀 cell 细胞 tissue 组织 organ器官saliva 唾液intestine (bowel)肠 small intestine 小肠 large intestine 大肠 abdomen 腹部 anus 肛门 excrete 排泄 pancreas 胰腺 bile 胆汁skull 头颅 rib 肋骨spine 脊椎 muscle fiber 肌纤维voluntary muscle 随意肌；横纹肌 involuntary muscle (smooth muscle)平滑肌contract 收缩windpipe 气管 lung 肺 exhale 呼气 inhale 吸气arteriosclerosis 动脉硬化 (blood)vessel 血管artery 动脉 vein 静脉capillary 毛细管 plasma 血浆 liver 肝脏urinary bladder 膀胱 kidney 肾脏 puberty 发育期 egg 卵sperm 精子uterus (womb)子宫 fertilize 使受精chromosome 染色体pregnant 怀孕gene 基因 genetically embryo 胚胎 fetus 胎儿hormone 荷尔蒙 neuron 神经细胞；神经元 reflex 条件反射neuroscience (neurobiology)神经系统科学（神经生物学）10. FOOD 食品food chain 食物链health food (green foodstuff)保健食品（绿色食品）convenience food方便食品 edible 可食用的 inedible 不可食用的 diet 日常饮食 dietary 饮食的FDA (the Food and Drugflour 面粉 bread 面包 pastry 面点心pista 面条类食品yeast (leaven; ferment)（名词）酵母；（动物）发酵 fruit 水果(beef) steak 牛排；鱼排ground beef (hamburger) 绞牛肉；牛肉酱 pork 猪肉 mutton 羊肉cheese 奶酪 cream 奶油ice cream 冰淇淋 粉）；糖类glucose 葡萄糖 fructose 果糖 maltose 麦芽糖 starch 淀粉 fat 脂肪fat-free 不含脂肪的the least fattening, of course protein 蛋白质 vitamin 维生素 calorie 卡（路里）nourishing (nutritious) 有营养的 malnourished 营养不良preserve 保存 additive 添加剂 packaging 包装快餐部 coffee shop 咖啡馆；小吃店 cafeteria 自助餐馆 menu 菜谱bar 酒吧beverage 饮料 wine 葡萄酒 liquor 烈性酒alcoholic 含酒精的buffet (meal)自助餐7word 版本可编辑.欢迎下载支持.egg （鸡）蛋fried egg (sunny-side up; over)荷包蛋（单煎一面；煎两面） scrambled egg 炒鸡蛋 poached egg 水煮荷包蛋ham and eggs(bacon; sausage)火腿蛋（熏咸肉；香肠） appetizer 开胃食品 course 一道菜dessert 甜食refreshments 茶点；点心spice (seasoning)香料；调味品 spread 涂抹食品的酱 dressing 填馅；调料 icing 蛋糕糖衣bake 烘（糕点等） roast 烤（肉等） barbecue 烧烤broil (grill)（在烤架等上面）烤 toast 烤（面包） stew (simmer)炖；焖 gourmet 美食家 connoisseur 鉴赏家11. PERSONALITY 个性character 性格characteristic(trait)特性；特征；特点 disposition(nature)性情；性格 temperament 气质；禀性 introvert 内向的 extrovert 外向的jubilant(exultant; rejoiced)喜悦的；喜气洋洋的ardent(fervent; passionate)热忱的 enthusiastic(warmhearted; zealous) 热心的；热情的sociable(social) 爱交际的 courteous 有礼貌的cordial(hearty; genial)热诚的；友善的 sincere(earnest; genuine)认真的；真心的 candid (frank; straightforward) 坦率的；直截了当的trustworthy(reliable; dependable)可信任的ingenuous 单纯的；天真无邪的amiable (amicable; affable)和蔼的；温柔的 considerate(thoughtful)体贴的；考虑周到的hospitable 殷勤好客的charitable(bountiful; generous)慈善的；慷慨的lenient(merciful; tolerant)宽容的；仁慈的 altruistic(unselfish)利他（主义）的 sympathetic(compassionate)同情的；怜悯的benevolent(humane; philanthropic)仁shrewd(sharp-minded)精明的 humorous 幽默的witty 机灵的；爱说风趣话的versatile (many-sided; multifaceted)多才多艺的competent(qualified)有才能的；够资格的prodigy(talent) 天才（尤指神童） assiduous(diligent; arduous; laborious)勤奋的；努力的ingenious(clever)心灵手巧的 judicious(wise; sensible)明智的frugal(thrifty; economical)勤俭节约的 intrusive(obtrusive)打扰人的；闯入的 impetuous(hasty)急躁的；鲁莽的 impulsive(rash)动的；莽撞的whimsical(odd; eccentric)多怪念头的；古怪的fanatic 狂热的vigilant(alert; watchful; wary)警觉的 incredulous(unbelieving)不轻信的 cautious (careful; prudent)谨慎的 scrupulous(discreet)严谨的 reticent (quiet; silent)缄默的composed (cool; calm; self-controlled)镇静的抑郁的；沉闷的depressed(dejected)压抑的 frustrated(disappointed)沮丧的 disillusioned 失望的；幻想破灭的 dispirited(down-hearted)情绪低落的 remorseful(regretful)悔恨的 pessimistic 悲观的忧虑的 dependent 依赖的docile(obedient)顺从的humble(unpretentious)谦恭的 sluggish(inactive; inert)无生气的tardy(unpunctual)行动缓慢的；不准时的adamant(dogged; insistent; unbending)坚定不移的indomitable(tenacious)不屈不饶的 undaunted(dauntless; intrepid)大无畏的 defiant(disobedient; challenging)公然不服从的conceited(proud)骄傲的 haughty(arrogant; supercilious)高傲的 dominant(governing)支配的；统治的 domineering(overbearing; tyrannical)盛气凌人的；专横的presumptuous(daring; audacious)放肆的；胆大妄为的imprudent (indiscreet; heedless)鲁莽的；厚颜的hostile(unfriendly)敌视的 sadistic 虐待狂的impertinent (rude; insolent)粗鲁的；无理的offensive (irritating; annoying)冒犯的；恼人的bad-tempered(ill-humored)坏脾气的 relentless(unrelenting)无情的 reckless(heedless)不顾后果的fraudulent (deceitful; dishonest)欺诈的；骗人的volatile(fickle; capricious; frivolous)多变的；反复无常的spiteful(hurtful, malicious)恶毒的avaricious(rapacious; greedy)贪婪的 stingy(miserly)吝啬的 snobbish 势利的clumsy(awkward)笨拙的ignorant(uninformed) 无知的incompetent(incapable; unfit)无能的；不胜任的irresponsible(untrustworthy; unreliable)不负责任的；不可靠的不冷不热的 placid(mild)温和的；宁静的apathetic(indifferent; unconcerned)冷漠的 detached(impartial)不偏不倚的 disinterested(fair; unbiased; unprejudiced)公正的12. MEDICINE 医学medicinal 药的；药用的 medicinal herb 草药medical 医学的；内科的medical care (treatment)医疗medical examination (checkup)体格检查 medical certificate 医生证明remedy(therapy)疗法injection注射anesthetic (narcotic)麻醉剂hypnosis催眠术surgery外科手术antibiotic抗生素antiviral抗病毒药antitumor drug抗肿瘤药；抗癌药sulfa磺胺类药analgesic (pain-killer) 镇痛药tranquilizer镇静剂opiate 镇静剂；麻醉剂contraceptive避孕药tonic补药lotion药水ointment药膏elixir (panacea; cure-all)万灵药euthanasia (mercy killing)安乐死administer服用（药物）pediatrician儿科医生dentist (dental surgeon)牙科医生gerontologist老年病医生dietician营养学家therapist (某种疗法制)治疗专家radiologist放射科医生anesthetist麻醉师pharmacist (druggist) 药剂师practitioner （私人）开业医生dispensary (pharmacy) 药房急救afflict 使受（疾病）之苦symptom症状coma (unconsciousness; faint)昏厥indigestion消化不良nauseate (vomit)呕吐diarrhea泻肚injury(cut; wound)受伤bruise淤伤；青肿hemorrhage (bleeding)出血disabled (handicapped)残废deformity (malformation; misshape)畸形cripple (limp; lame)跛足myopia (nearsightedness)近视眼AIDS 爱滋病syphillis梅毒cancer癌症carcinogen致癌物benign良性malignant恶性epidemic流行病endemic地方流行的（病）incidence发病率toll伤亡；死亡influenza (flu)流感measles麻疹malaria疟疾cholera霍乱contagious（接触）传染的contaminate污染；感染inflammation炎症microorganism(germ; bacteria)微生物；细菌virus病毒susceptible 易患（某种）疾病chicken pox水痘mumps腮腺炎tuberculosis肺炎hepatitis 肝炎polio脊髓灰质炎；小儿麻痹症血吸虫病hypertension (high blood pressure)高血压heart attack心力衰竭；心脏病发作stroke中风electrocardiograph心电图arthritis关节炎rheumatism风湿病diabetes糖尿病bronchitis支气管炎anemia 贫血insomnia失眠症obesity肥胖症allergy过敏asthma气喘；哮喘appendicitis阑尾炎chronic慢性inspect（食品等的）检查immunization免疫vaccination疫苗complication并发症incubator（婴儿）恒温箱13. MATHEMATICS数学pure mathematics纯粹数学applied mathematics应用数学calculator计算器abacus算盘numeral数字sum和total (sum total)总和；总数aggregate总计fraction分数；小数decimal 十进位；（十进）小数digit数字；数位percentage 百分比addition加法plus加以subtraction减法minus减去multiplication乘法multiplication table乘法表multiply乘以times（介词）乘以power乘方square平方division除法divide除以over(介词)除以denominator分母numerator分子quotient商unknown quantity未知数（量）equation方程式；等式formula (复数formulas formulae)公式root根square root平方根平面几何solid geometry立体几何geometric几何的dimension维parallel （形容词）平行的；（名词）平行线perpendicular (vertical) 垂直的quadrilateral四边形square正方形area面积rectangle (oblong)长方形；矩形polygon多边形rhombus菱形；菱形六面体trapezoid 梯形cube立方形volume体积sphere球形circle圆形ellipse (oval)椭圆形cone圆锥形circumference圆周diameter直径equilateral triangle等边三角形angle角right angle直角acute angle锐角obtuse angle钝角degree （角）度8word版本可编辑.欢迎下载支持.9word 版本可编辑.欢迎下载支持.微分学 integral calculus 积分学statistics 统计 tabulating 列表quantitative 量的；数量的 qualitative 质的；质量的 summarization 总结；归纳sample 抽样random 随机的；任意的 logic 逻辑deduction (inference) 推论；演绎 induction 归纳hi-tech (high tech; high technology)高科技sophisticated (advanced)先进的 precision 精密；精确electronic robot 电子机器人 electronic camera 电子摄像 electronic organ 电子琴electronic hearing aid 电子助听器Internet 电脑互联网络；因特网 World Wide Web WWW 网络 modem 调制——解调器information superhighway 信息高速公路 on-line service 网上服务 microcomputer 微型电脑cellular phone (telephone)大哥大；移动电话cordless telephone 无绳电话通讯卫星微波炉 激光唱片；光盘 CD-ROM 光盘只读存储器fiber-optic cable 光纤电缆fiber-optic communication system光纤solar collector (furnace)太阳能收集器 solar cell 太阳电池synthetic （名词）合成物 counterpart 对应的物或人 synthetic resin 合成树脂organ transplanting 器官移值 artificial insemination 人工授精 clone 克隆；复制15. EDUCATION 教育preschool(preelementary)education 学龄前儿童教育elementary (primary) education 初等教育 secondary education 中等教育tertiary(higher) education 高等教育 adult education(continuing education)成人教育special education 特殊教育 education 教育的educational facilities 教育设施 compulsory 义务的；强制的 intellectual 智力的human resource development (training)人才开发；培训 acquisition 获得moral character 道德品质elementary school 小学 middle school 初中 high school 高中vocational high school 职业学校 technical high school 技校institution of higher learning(education))学院 community college 社区大学 institute （专科）学院；研究院 department 系 campus 校园catering (meals)膳食accommodation （lodging ）住宿 grader 某年级学生freshman （大学和高中）一年级学生 sophomore （大学和高中）二年级学生 junior （大学和高中）三年级学生senior （大学和高中）四年级学生 undergraduate 本科生 graduate(student)研究生fellow （大学接受奖学金的）研究生 academic 学术的academic performance 学习/业表现 transcript 学生成绩报告单 credit (credit hour)学分grade(score)分数；分数等级 grade point 积分点grade-point average 平均积分点 pass-fail option 考查课graduation thesis(paper)毕业论文 completion (of studies)完成学业satisfy (fulfil; meet) the requirements 达到要求（考试及格）commencement (graduation)exercise admissions office 招生办公室 entrance examination 入学考试Scholastic Aptitude Test (SAT)学习能力倾向测验recipient 接受者 semester(term)学期 quarter 学季summer session 夏季班 tuition学费non-refundable 不退还的prospective 未来的；即将成为的 financial aid (assistance)资助 stipend 奖学金scholarship （本科生）奖学金 fellowship （研究生）奖学金assistantship （半工半读）奖学金 program 教学计划；课程 discipline 学科liberal arts(humanities)文科 science course 理科 engineering course 工科 curriculum 全部课程 extracurricular 课外的 syllabus 教学大纲 vacation(holiday)假日 course 课程introductory course 基础课程 required course 必修课 elective(course)选修课treasurer 生活委员/财务大臣 elective system 选课制度 learn by rote 死记硬背encyclopedias 百科全书/专科全书 honor course(为)优秀生（开的）课 major 专业seminar 讨论会；研究班课程award (confer)授予（学位、证书） diploma (graduation certificate)毕业证书 degree 学位associate degree 准学士学位 bachelor’s degree 学士学位 master’s degree 硕士学位do ctor’s degree (doctorate)博士学位 educational background (education)学历 qualification 资格 honor 奖励；荣誉experience (work experience)工作经历 special skill 特殊技能proficiency （语言）精通；熟练 expertise 专长personal (personal information)个人情况marital status婚姻状况reference推荐人；介绍人推荐信professor（正）教授associate professor副教授assistant professor助理教授instructor（大学）讲师tutor（大学）助教chairman(chair) 系主任dean（大学学院）院长principal(中、小学)校长president (chancellor)（大学）校长alumnus（复数alumni）男/校友alumna(复数alumnae)女校友alma mater母校16. 建筑学a glass-shelf framed in a metal gridprototype原型architecture建筑学architect建筑学家beam 梁building material建筑材料building technique 建筑工艺construct/construction建设design element 设计元素elevator 电梯gas station 加油站glass boxlog structure 原木结构metal-frame 金属结构new material 新材料office building写字楼planetarium天文馆archives档案馆aquarium水族馆cabin 小木屋castle城堡cathedral大教堂mosque清真寺pyramid金字塔repair person修理工skyscraper摩天楼Sphinx狮身人面像the Statue of Liberty自由女神像the Triumphal Arch凯旋门wing 辐楼/侧楼17. 电影animated cartoon卡通片cameraman摄影caption字幕cartoon卡通片cast演员表；全体演员close-up特写镜头director导演documentary纪录片editing剪接feature film故事片illumination照明light effect灯光效果long shot远摄montage蒙太奇newsreel新闻片review试演script电影剧本setting布景shoot film拍摄电影sound effect音响效果studio电影厂theme song主题歌18. 摄影photographycamera lens相机镜头close-up特写darkroom暗室depth of field景深developing冲洗enlarge放大exposure爆光filter滤色镜focus焦点background背景foreground 前景high definition高清晰度instant camera拍立得lens镜头focus lens长镜头out of focus调焦不准panorama全景照photographer摄影家snap shot快照tripod三角架wide angle lens广角镜头19. 美术(绘画和雕塑)brush 画笔canvas油画布drawing board画板caricature漫画charcoal drawing木炭画engraving版画landscape painting风景画lithograph石版画fresco 壁画mural壁画mural painting壁画Oil painting油画pastel 彩粉画portrait肖像画sketch速写；素描still life静物画water color水彩画tempera蛋彩画panorama全景画pastel彩色蜡笔画poster海报/招贴画genuine真的fake假的fine arts美术gallery美术馆mix colors 调色original原作copy临本perspective 透视画法replica复制品reproduction复制品sculptor雕塑家statue塑像bust半身雕塑像figurine小雕像sculpture雕塑framing装框pigment 颜色，色素autograph 真迹calligraphy书法paste裱糊impressionistic style印象派风格animator 漫画家indigo靛蓝purple紫色20. 文学prose散文diary日记autobiography传记editorial社论narrative prose 叙述descriptive prose描写性essay随笔poetry 诗歌ballad 民谣Lullaby 催眠曲Fiction 小说allegory 寓言fairy tale 童话legend 传说proverb谚语prelude序曲prologue 序言epilogue 尾声model人物原型leading character主人公main plot主要情节protagonist主人公literary criticism文学批评literary studies文学研究Schools of literature文学流派Comparative literature比较文学Realism现实主义Modernism现代主义Aestheticism唯美主义Futurism 未来主义vignette小品文prolific多产21. 舞蹈10word版本可编辑.欢迎下载支持.。
Java中的RPC框架比较和选择随着分布式系统的普及和发展，远程过程调用（RPC）框架在构建高性能、可扩展性的应用程序中扮演着至关重要的角色。
Java作为一种广泛使用的编程语言，有许多优秀的RPC框架可供选择。
本文将介绍几种常见的Java RPC框架，并对比它们的特点和适用场景，以帮助开发者在选择RPC框架时做出明智的决策。
1. Apache DubboApache Dubbo是一款高性能、轻量级的开源RPC框架。
它支持多种通信协议和序列化方式，可以很好地满足不同场景下的需求。
Dubbo 具有简单易用的特点，提供了丰富的扩展点，可实现自定义的负载均衡、容错策略等功能。
它还支持服务治理，包括服务注册与发现、动态路由等，使得服务的管理更加便捷。
Dubbo广泛应用于大规模分布式系统。
2. Spring Cloud NetflixSpring Cloud Netflix是基于Spring Cloud的一套组件，其中包括了Netflix开源的一些框架，如Eureka、Ribbon、Hystrix等。
Spring Cloud Netflix提供了一套完整的微服务解决方案，包括服务注册与发现、负载均衡、熔断器等，使得开发者可以更方便地实现分布式系统。
它与Spring框架完美集成，使用起来十分方便。
3. gRPCgRPC是由Google开发的一种高性能、跨语言的RPC框架。
它使用Protocol Buffers作为接口定义语言，并基于HTTP/2协议进行通信。
gRPC支持多种编程语言，包括Java、C++、Python等，可以方便地构建跨平台的分布式系统。
gRPC提供了异步和流式处理等功能，能够显著提高性能和效率。
4. Apache ThriftApache Thrift是一款多语言的开源RPC框架，支持多种传输协议和序列化方式。
它可以自动生成代码，提供了简单易用的接口定义语言，使得开发者可以方便地定义和实现跨语言的服务。
cfrunloopobservercreate方法CFRunLoopObserver是Core Foundation框架中的一个重要类，用于观察和控制运行循环（RunLoop）的行为。
在Core Foundation框架中，RunLoop是用于处理事件循环的机制，它负责管理线程的事件分发和处理。
而Observer则是观察者模式中的一个关键角色，它可以在特定的事件发生时被触发并执行相应的操作。
在Core Foundation框架中，Observer模式通常用于处理异步操作和事件驱动的应用程序。
通过使用Observer模式，应用程序可以轻松地实现事件监听和响应机制，从而简化代码的编写和维护。
cfrunloopobservercreate方法是Core Foundation框架中用于创建RunLoop观察者的方法。
该方法用于创建一个Observer对象，并将其注册到指定的RunLoop中。
通过调用cfrunloopobservercreate 方法，您可以为特定的对象或线程注册一个观察者，以便在特定的事件发生时触发相应的操作。
下面是一个简单的示例代码，演示如何使用cfrunloopobservercreate方法创建一个RunLoop观察者：```objectivec// 创建观察者对象CFRunLoopObserver *observer = (CFRunLoopObserver*)[NSClassFromString(@"YourObserverClass") new];// 创建运行循环对象CFRunLoopRef runLoop = CFRunLoopGetCurrent();// 将观察者注册到运行循环中if (CFRunLoopAddObserver(runLoop, observer, kCFRunLoopDefaultMode) != kCFReturnSuccess) {// 注册失败的处理逻辑}```在上面的示例中，我们首先创建了一个观察者对象，并将其类型强制转换为CFRunLoopObserver类型。
APOLLO:Multiplexed Lunar Laser Ranging T.W.Murphy,Jr.,E.G.Adelberger,J.D.Strasburg,&C.W.Stubbs Dept.of Physics,University of Washington,Seattle,WA98195-1560AbstractThe Apache Point Observatory Lunar Laser-ranging Operation(APOLLO)is a next-generation lunar laser ranging(LLR)campaign aimed at order-of-magnitude improvementsin tests of gravitational physics via millimeter range precision.We will employ the3.5mtelescope at the Apache Point Observatory(APO),located in southern New Mexico at analtitude of2800m.As a result of the large aperture size and excellent seeing conditionsat the site,APOLLO expects to detect2–10lunar return photons per pulse.Relativebackground immunity permits operation in daylight and at full moon,resulting in bettersampling of the lunar orbit.We will use avalanche photodiode(APD)arrays as the detector for APOLLO,allow-ing multiple photons within a single return pulse to be individually time-tagged with highprecision.Immediate advantages are shot-by-shot range profiles,as well as guaranteed cal-ibration for each shot.In conjunction with a high time-precision start photodiode,onequickly builds an accurate representation of the convolved laser-detector-electronics tempo-ral response.We describe here the hierarchical,multiplexed APOLLO timing system andits implementation using commercial electronics and a programmable logic controller.Wealso discuss the various calibration procedures geared toward millimeter precision.Thereis no practical limit to the number of channels employed in our timing scheme,allowing anupgrade path to larger APD array formats(10×10or larger)in the future.1IntroductionLunar laser ranging(LLR)has provided a laboratory for tests of fundamental physics for over three decades[1,2].Centimeter-precision range information provides measurements at the part in 1013level by comparison to solar-system-scale phenomena.As we build the lunar-range database, some measurements become increasingly sensitive with the passage of time even without im-provements in the range precision.For example,sensitivity to the time variation of Newton’s gravitational constant,G,improves as the square of the observation time—now constrained at the impressive level of less than a part per trillion change per year[3].While LLR may still deliver improved tests of physics in the years to come,the poten-tial for order-of-magnitude improvements is best enabled by a new campaign intent on making order-of-magnitude improvements to the range precision itself.Current systems deliver range normal-points with typical uncertainties around2cm[4].The greatest impediment to substan-tial improvement in range precision is photon number.Because the strength of the return signal from a passive reflector varies as the inverse fourth-power of distance,laser ranging to the moon is at the very limit of detectability.For example,the McDonald Laser Ranging Station(MLRS, [5])at its very best detects just over one photon per minute(600laser shots),placing about15 photons into one normal point.From a purely statistical standpoint,order-of-magnitude range improvements would necessitate∼1500photons per normal point—well beyond the capabilities of current LLR stations.By establishing lunar range capability on the3.5m telescope at the Apache Point Observatory, we anticipate moving into the multiple-photon-per-pulse regime[6].At a20Hz pulse repetition rate,the requisite photon number is accumulated in a matter of minutes.However,the high photon return rate presents instrumental challenges if one is to measure the lunar distance in an unbiased way.In particular,a signal consisting of a few photons is not large enough to reliably define a pulse shape on which one could perform a meaningful centroid or leading-edge measurement.Nor is this signal strength suitable for single-photon detectors such as avalanche photodiodes(APDs),which ignore all but thefirst detected photon.We will describe here the technique adopted for APOLLO to perform an unbiased measurement on a pulse containing a small number of photons.This paper will largely concentrate on the timing scheme employed to accommodate an arbitrary number of single-photon detector channels,which for APOLLO assumes the form of an APD array.APOLLO expects to deliver range precision in the neighborhood of one millimeter.This high level of precision will undoubtedly expose many model deficiencies,almost all of which will be associated with earth deformations and atmospheric influence.Even before the model has time to catch up to APOLLO’s precision,we will be able to extract gravitational physics measurements out of the dataset,since these appear at very well-defined frequencies,unlikely to be mimicked by aperiodic backgrounds or by periodic influences at different frequencies.Within the course of several years,APOLLO will produce order-of-magnitude improvements in fundamental physics parameters.Specifically,APOLLO will provide the very best tests of the following aspects of gravity,to the precisions indicated:•Test of the strong equivalence principle to3×10−5•Test of the weak equivalence principle with∆a/a≈10−14•Measurement of˙G/G to10−13yr−1•Test of the1/r2law at the lunar distance scale to∼10−12•Measurement of geodetic(de Sitter-Fokker)precession to∼3×10−4The test of the strong equivalence principle tests how gravitational energy itself gravitates—a crucial nonlinearity predicted by general relativity[7,8,9].The weak equivalence principle probes compositional differences in the accelerations of two bodies,and will exceed laboratory tests of the same[10].Characterization of˙G addresses the evolution of fundamental coupling constants against the backdrop of the expanding universe[11,e.g.].The test of the inverse square law searches for new long-range forces,and may be able to subject certain brane-world cosmological scenarios to critical tests[12,13].Measurement of relativistic geodetic precession provides a measure of the curvature of local spacetime,and the effect this has on the orientation of coordinate systems[14].In addition to the aformentioned gravitational measurements,APOLLO will deliver order-of-magnitude gains in lunar science,geodesy,coordinate determinations,etc.Especially improved will be lunar science,because the high photon return rate will enable range measurements to the complete set of lunar reflectors during each observation.Thus the lunar orientation and deformation will be very precisely determined.2APOLLO Photon RateThe high photon rate expected from APOLLO is the key to achieving substantial gains in pre-cision.The principal factors enabling APOLLO to accomplish its millimeter goal are the large telescope aperture and the excellent atmospheric seeing experienced at the site.The median net image quality of the APO3.5m telescope for long exposures is1.05arcseconds.A crude scaling of APOLLO to OCA(Observatoire de la Cˆo te d’Azur:1.5m,2.5arcsecond image quality [15])and MLRS(0.78m,4arcsecond image quality[5])indicates a signal gain of35and300, respectively.A gain of this magnitude(roughly102)is necessary for a single order-of-magnitude improvement in random range uncertainty.A bottom-up calculation of the expected photon return rate based on the familiar link ef-ficiency equation is also illuminating.For APOLLO’s parameters,we calculate the following number of return photons per laser pulse:N det=5.4× E115mJη0.42 f0.25Q0.3n1001asecΦ2 10asecφ2rr4photons.Here,E is the pulse energy,ηis the one-way optical efficiency,f is the receiver throughput (dominated by narrow-bandfilter),and Q is the detector efficiency.We assume one arcsecond seeing,pointing toward the smaller of the Apollo arrays(100array elements),10arcsecond divergence out of the corner cubes,and the moon at its mean distance.We have been intentionally pessimistic with regard to optical efficiencies,but nonetheless calculate a detection rate of5 photons per pulse.This return rate exceeds that routinely experienced at OCA and MLRS by a factor of roughly1000—at odds with the simpler scaling in the previous paragraph.Although the link efficiency equation as applied to current LLR stations yields photon rates roughly an order-of-magnitude too optimistic for current LLR stations,this is not the case when applied to the LLR system that once operated on the2.7m telescope at McDonald Observatory. At roughly0.8photons per pulse,this system had a high enough photon return rate to enable real-time optimization of the system[16].APOLLO will likewise operate in this regime.Even a factor of100degradation in efficiency(due to pointing,focus,etc.)will produce one photon per second—enough to attempt real-time adjustment of pointing,focus,transmit/receive misalignment,and beam collimation.All of these adjustments are actuated in APOLLO,allowing an automated optimization routine tofind the parameters that yield peak performance.Another indication that this expectation may be reasonable comes from the best historical performance of the MLRS and OCA LLR stations.Without the ability tofine-tune performance in a closed-loop,algorithmic manner,the idealized system capabilities are perhaps best charac-terized by the lucky occasions when the systems happened to be tuned to optimum performance. MLRS,for instance,reports receiving120photons in41minutes on the Apollo15reflector[17]. Considering the time spent steering the telescope,one might estimate a peak instantaneous rate of one photon every10seconds,or0.01photons per pulse.For OCA,a return rate of0.1pho-tons per pulse was obtained on the Apollo15reflector[18].Blindly scaling these rates by the factors computed above based on aperture and seeing alone,one predicts a peak photon rate for APOLLO of about3photons per pulse.So far,the issue of background noise has been left out of the discussion,but here too APOLLO enters a new regime—owing largely to the very small acceptedfield of view of1.2arcsec.Because of this,APOLLO will be able to operate in full moon or daylight conditions without significant noise contamination.We predict about0.2photons per pulse per100ns gate,on the full moon.Figure1:The4×4APD array APOLLO will use,courtesy of Lincoln Labs.The array elements are30µm in diameter,separated by100µm.Spatial information is preserved in the pixelated grid,and may be used to perform real-time guiding on the return signal.Within the∼1ns spread of lunar photon returns,our signal-to-noise ratio is∼500with a signal return as low as one photon per pulse.3Array DetectorTraditionally,laser ranging(e.g.,to satellites)has operated in either the single-photon mode—relying on the assumption that“double”photons are rare—or in large-signal mode,whereby the pulse shape is represented directly in the detector response.For our intermediate photon rate,neither is particularly suitable.Ideally,we would like to time-tag each detected photon individually.A single detector is incapable of this,because the detector response time is longer than the duration of the photon bundle.A multiplexed scheme is called for.One technique would string many single-element detectors along a chain of beam-splitters,such that each detector statistically receives some fraction of the incident light.Another technique is to use an array detector,spreading the return light spatially across the array such that any given element is again statistically likely to receive some fraction of the input light.In collaboration with MIT Lincoln Laboratories,we have access to the APD array technology developed there.By fabricating APD structures into a monolithic silicon substrate,they have produced4×4and32×32array formats(see Figure1).The elements have active areas of20, 30,or40microns,placed on a square array pattern with100µm spacing.Details about the detector arrays may be found elsewhere[19].The APD array that will initially be used in APOLLO is a4×4format with30µm elements (Figure1).Because we want each of the elements to operate in single-photon mode(or an approximation to this),we want the likelihood of photon detection per element to be<0.25, or about4photons across the array per pulse.At this upper limit,25%of the detections will statistically be“double”detections,and a substantial bias correction must be applied—less for weaker returns.It has yet to be determined how high this upper limit should be for recovery of millimeter net accuracy in locating the geometrical center of the retroreflector array palette.The “comfort-zone”for an array of this size is around1–3photons per pulse,right where APOLLO expects to operate.4Multi-photon CalibrationThe technique of measuring the time of departure of the outgoing laser pulse through the use of a corner-cube or other reflector in the telescope exit aperture is here called calibration .Serving as a time fiducial,this internal “return”allows one to make a differential measurement of target range by referencing the target return time to that of the corner-cube return.If measured in the same way as the target return,the calibration return eliminates systematic errors that are common to both paths.Because it is necessary to measure both signals in the same manner,the calibration return must be attenuated to the level of the target return—down to the few-photon level.Here,the multiplexed approach offers a benefit over single-photon mode in that one may tune the calibration signal to generate several detected photons per pulse,and in doing so greatly reduce the number of pulses that have no fiducial reference.For example,if the system is operating at the 0.1photon-per-pulse level,and the calibration is tuned to the same,only about 1%of the target returns will by chance have a calibration return associated with the same pulse.On the other hand,if the system is operating at N photons-per-pulse,the likelihood of detecting no calibration photons in a given pulse is e −N ,or less than 5%for N =3.Thus one achieves greater assurance that each return shot has a fiducial time against which to compare.Complete reliance on the calibration pulse to compute the round-trip travel time ∆t =t target −t cal would tend to produce uncertainties that are √2times worse than the uncertainty of the target or calibration measurements separately.One can improve on this by also measuring the laser fire time using a fast photodiode and a constant-fraction discriminator to obtain a high signal-to-noise ratio estimate of the laser pulse time [21].Comparison of the photodiode start with the target return does not qualify as a differential measurement,since the two are measured in wholly different ways.But one may nonetheless reference the calibration-return-time to the laser-fire-time,using the laser fire as a precision “anchor ”.The interval between the time anchor and the calibration return may vary as environmental conditions change—such as optical paths,cable delays,and electronics responses.But these changes are likely to be slow,with timescales of several minutes or more.Under the assumption that the anchor drifts slowly,over short timescales one may reference the time of each calibration photon to this temporary fiducial.In this way,even calibration returns of only one photon may be properly placed with respect to the departure time of the center of the pulse.Figure 2demonstrates this concept.At top is the system response—a convolution of laser pulse shape,detector jitter,electronics jitter,etc.This represents the distribution one would see emerge after a large number of photon events were recorded.The yellow vertical line indicates the centroid of the distribution.The rising edge of the laser pulse is detected by the fast photodiode,represented here as a thick green line.The placement is misleading since the calibration return arrives long after the photodiode trigger.But in a gedanken manner,one can simply delay the photodiode report until its relative position is as shown here.Note that the single-shot mean,shown as vertical pink bars in Figure 2,“jumps”around by ∼σ/√N ,where σis the standard deviation of the convolved instrument response,and N is the number of photons in a given shot.The photodiode anchor eliminates this noise source,placing the photon events in their proper places (e.g.,shots 3and 11).Over five minutes,operating at 20Hz and 2.5photons per pulse,15,000calibration photon events are recorded.Thus one may build up an accumulated system response distribution with many events per time bin,approaching the black curve at the top of the figure.This distribution will differ from the target return by the small contribution from the fast photodiode jitter,and the generally larger contributionFigure2:The multi-photon calibration scheme.Fourteen representative shots are displayed at an average rate of4.5photons per shot.Arrows represent individual photons.The vertical pink lines are the means within a shot.The thick green line is the high-precision photodiode start time.The profile at top and the vertical yellow line represent the accumulated properties of the photon time distribution.from the target signature.Because the former is small,the latter may be directly determined by deconvolving the target response profile by the calibration response profile,provided that multi-photon biases have been properly treated.In practice,once the offset between the photodiode anchor and the short timescale calibration ensemble mean(labeled as the pseudo-static offset in Figure2)is determined,the time of arrival of target return photons may be directly referenced to the high-precision photodiode anchor time for that particular shot.The offset can be established based on a sliding averaging time—e.g.,a time window of±2minutes about the current time.The character of the offset may be studied to determine appropriate timescales over which the assumption of slow changes holds,and as a tool for evaluating sources of systematic error.5Multiplexed Timing SchemeA key ingredient of the APOLLO timing scheme is a16-channel time-to-digital converter(TDC) made by Phillips Scientific(model7186H[22]).At its highest resolution,the TDC measures intervals between0–100ns,at12-bit(25ps)resolution.Our tests show that its RMS jitter is around13ps per event.The TDC is responsible for measuring the time between photon arrival and afiducial time mark derived from a precision oscillator.Figure3shows the general idea.At some time,in reference to the clock pulse train,the APD is turned(gated)on,after which photons may trigger detection events,and send START pulses to individual TDC channels. Figure3schematically displays six APD channels operating independently.Among the events depicted are four events clustered in a return packet,one sporadic background event,and oneFigure3:Schematic timing scheme.Photon events may occur within the APD gate,which is referenced to the50MHz clock.The time between the photon events and a selected clock pulse after the gate is measured for each channel by the TDC(pink arrow).channel for which no photons were detected while the gate was on.After the gate is turned off, the next rising edge of the clock serves as a common STOP pulse to the TDC.Thus each TDC channel measures the interval between the photon event and thisfiducial stop time.Now if we simply know which clock pulse acted as the STOP,and the associated time,we then have all we need to measure the time between pulse departure and pulse return:∆t= t STOP2−∆t TDC2−t STOP1+∆t TDC1+t offset.The clock pulses may be counted continuously,and the counters latched on STOP events for readout.Reseting the counter once per second then ascribes more meaning to the count value:the time within the second.If the one pulse-per-second signal is derived from a clock synchronized to UTC,then the time of photon arrival may be determined to an accuracy of∼50ns(GPS−UTC accuracy),and a relative precision of ∼35ps(dominated by the APD).This is essentially the hierarchical scheme employed in APOLLO,composed of three pieces: clock time in seconds,pulse number in20ns intervals,and TDC measurement to25ps resolution. We additionally must predict the appropriate time to turn on the APD so that we catch the lunar return.A block diagram of the digital timing scheme appears in Figure4.Each of the large boxes is clocked by a50MHz digital clock signal.The gate width control and the target delay counter are each counter/comparator schemes that send out a20ns pulse(CLOSE and target START,respectively)when some prescribed count is reached.For example,the counter in the gate width control is reset at either photodiode or target START signals,and counts in20ns intervals(corresponding to the50MHz clock)until the prescribed value,say5,is reached.At that time,the APD gate is commanded to CLOSE,having been OPENed by the START pulse. The target delay counter is never reset,and has a wrap period of5.4seconds.At a gate CLOSE event,the counter value is latched and its data made available to the controlling computer.In the case of a calibration gate event—the one associated with laserfire—the target delay for that pulse is computed and fed via afirst-in-first-out(FIFO)queue back into the target delay counter. When the free-running50MHz counter reaches this count,a target START event is generated.Also shown are a few time-keeping blocks:the counts-per-second(CPS)block,and the time-within-second(TWS)block.The TWS counter is clocked at50MHz,and reset on the rising edge of the one pulse-per-second(1PPS)signal from the GPS clock(TrueTime XL-DC).Because the 1PPS signal is derived from the50MHz GPS signal,these two are co-phased.By latching thewidth set photodiode STARTdelay value in to APDdata out delay data out STOP Select START Select1 Pulse per second data outFigure4:Block diagram of the APOLLO timing scheme.All blocks are clocked at50MHz. value of the TWS counter at a CLOSE event,the exact clock pulse associated with the CLOSE event is unambiguously identified.Thus the time of the gate event within the GPS-clock-defined second is identified.The free-running counter,also latched by the CLOSE event,serves as a redundant check of the clock pulse number associated with the gate event.The CPS counter is another redundancy to verify proper counting of all clock pulses.Both latched and reset on the 1PPS signal,this counter should always read50,000,000(minus two,as implemented).The CLOSE and START signals perform another critical role in addition to the APD gate control.These20ns logic pulses are used to enable comparators whose input is the raw50MHz sine wave from the GPS clock.By bracketing a single positive voltage-swing of the sine wave with the20ns enable pulse,we can send a single clock pulse out of the comparator and to the TDC.In this way,the CLOSE signal slices a chosen clock pulse to act as a STOP,and optionally,the OPEN signal selects a START for the TDC.This latter capability allows us to send a START/STOP pair to the TDC whose time separation is a precise multiple20.0ns—depending on selected gate width—uncertain at the10ps level.The START pulse is simultaneously applied to all16input channels of the TDC,by way of the TEST input.In this way,we can calibrate each channel of the TDC against an absolute standard.At a data rate of1kHz,one may perform a sweep of the TDC at20,40,60,80,and100ns intervals in less than ten seconds,accumulating more than a thousand data points per interval.Rapid and frequent calibration will aid in the understanding and elimination of systematic errors.The logic block of Figure4also shows various data paths.The inputs are used to set the width of the gate and the count associated with the next target event.The outputs pass the latched counter values.A computer controls this information exchange,recording data and calculating new target delay values.This general timing scheme relies on multiplexing capability only in the TDC unit.The number of channels employed is irrelevant(until data input/output operations become limiting). APOLLO can easily upgrade to larger detector formats simply by employing additional TDC units.Figure5:Approximate logic function of the main portion of the TIMER chip.Counters clocked at50MHz trigger events when their counts reach the values set in the adjacent registers.At top left is the gate width control,at top right is the APD gate control,at left center is the target delay generator,and at lower left is the time-within-second recorder.6Implementation:The APOLLO Command ModuleThe digital logic associated with the APOLLO timing scheme has been implemented on a custom CAMAC module called the APOLLO Command Module(ACM).The ACM is little more than two Altera programmable chips(MAX-7000AE series)interfacing to the CAMAC dataway and to various external hardware.The TIMER chip performs the timing logic,and contains the elements schematically depicted in Figure4.The CAMAC chip controls the CAMAC interface, parsing commands,passing data,and setting the operating state of the TIMER chip.The chips are re-programmable in situ up to1000times.Thus the details of the logic functions may be changed via software,without needing access to the hardware.A schematic example of the core elements in the TIMER chip(those represented in block form in Figure4)is shown in Figure5,though the details of the real implementation differ.The function of the ACM extends beyond that of counting clock pulses and controlling the APD gate. In total,the ACM performs the following tasks:•keeping track of time(counting clock pulses and registering significant epochs),•opening the APD gate in anticipation of photon arrival,•controlling the duration of the APD gate,•firing the laser in synchronization with the rotating transmit/receive switch,•telling the50MHz stage when to send a STOP pulse to the TDC,Figure6:Oscilloscope trace of the ACM output,showing the OPEN signal and the GATE signal, about6ns later.The crossing at top is confusing,but the OPEN pulse is the shorter(20ns) pulse that risesfirst.•sending a time request to the GPS clock once per second,•controlling entry into“stare”mode,allowing the APD to sense stars,•blocking the laser when safety demands,•and calibrating the TDC with pulses separated by precise multiples of20.00ns.In addition,the ACM has safety features built in to prevent accidental damage to the APD or laser.There are alsofive as-yet unassigned ports,configurable as input or output,that may be used for future purposes.Potential uses include deploying corner cubes,setting the state of variable attenuators,etc.The CAMAC communication rate is relatively high-speed,with a typical command duration of 1.5–2.0µs.Test trials of the ACM controlled from a Linux machine running the stock RedHat7.1 kernel(2.4.7)showed that the computer was able to keep up with the data rate(about12CAMAC commands per cycle)with no dropouts at rates of300Hz.Data dropouts were less than0.5% up to about20kHz,becoming50%at∼40kHz.It is at this point that the duration of the CAMAC command sequence—mostly reading data from the TIMER chip—exceeds the cycle time.These tests are somewhat unrealistic for thefinal control loop,because the roughly20 commands necessary to read and reset all TDC channels were not included.Nonetheless,this scheme is capable of operation at several kHz in a practical ranging application.The few dropouts that do occur can be eliminated or reduced by applying low-latency patches to the Linux kernel, or by running Real-Time Linux,or some other low-latency operating system.Figure6shows the appearance of ACM output pulses.In particular,the APD gate and the OPEN request pulses are shown.Each is a multiple of20ns in duration.The OPEN request is generated by the target delay counter,shortly followed by the gate pulse.A picture of the“business end”of the ACM is shown in Figure7.The CAMAC card-edge connector and input/output buffers are left out of this picture at bottom.At upper left is the。
