压控振荡器（VCO）技术综述
1. 前言
压控振荡器(voltage-controlled oscillator, VCO) 是一种以电压输入来用来控制振荡频率的电子振荡电路,是现代无线电通信系统的重要组成部分课题。在当今集成电路向尺寸更小、频率更高、功耗更少、价格更低发展的趋势下，应用标准工艺设计生产高性能的压控振荡器已是射频集成电路中的一个重要课题。环形振荡器易于集成，可调频率范围大，但相位噪声不如性能不如LC振荡器。LC 压控振荡器要求高品质因素的无源器件，需要片上电感和变容管器件才能集成集成。
振荡器自其诞生以来就一直在通信、电子、航海航空航天及医学等领域扮演重要的角色，具有广泛的用途。在无线电技术发展的初期，它就在发射机中用来产生高频载波电压，在超外差接收机中用作本机振荡器，成为发射和接收设备的基本部件。随着电子技术的迅速发展，振荡器的用途也越来越广泛，例如在无线电测量仪器中，它产生各种频段的正弦信号电压:在热加工、热处理、超声波加工和某些医疗设备中，它产生大功率的高频电能对负载加热;某些电气设备用振荡器做成的无触点开关进行控制;电子钟和电子手表中采用频率稳定度很高的振荡电路作为定时部件等。尤其在通信系统电路中，压控振荡器(VCO)是其关键部件，特别是在锁相环电路、时钟恢复电路和频率综合器电路等更是重中之重，可以毫不夸张地说在电子通信技术领域，VCO几乎与电流源和运放具有同等重要地位。
2. 主题
2.1 VCO的发展过程
上世纪初，Armstrong发明了电子管振荡器，经Hartley改进电路设计并开发成功电子管VCO。电子管VCO的振荡频率是通过改变振荡电路中电感器或电容器的参数值来进行调节。当时人们对电子管振荡电路开展了大量的研究，今天仍在沿用的Hartley，Colpitts，Clapp，Armstrong，Pierce等经典振荡电路结构，就是当时的研究成果。
上世纪中叶，晶体管问世并很快取代电子管成为振荡电路的有源器件。特别是变容二极管的应用对VCO的发展具有重要意义。变容二极管的电容随外加电压的改变而变化，用变容二极管作压控器件，改变其控制电压就可实现VCO振荡频率的调节。这样，晶体管、变容二极管和其他无源元件就构成了分立式的晶体管VCO。这种晶体管VCO实现了振荡频率的电子调谐，这是变容二极管对VCO发展的重大贡献。与电子管VCO相比较，晶体管VCO具有电子调谐、体积小、成本低、功耗小、质量好、调频范围设置简便等优点。晶体管VCO的发展也是是电视技术能在当时迅速推广的重要原因。1960年至1980年，晶体管VCO被电子系统设计所广泛采用。到了1980年，情况发生了变化，混合集成的VCO组件和单片集成的VCO IC出现了。这两种新技术对VC0的发展产生了重要的影响。VCO从此就开始步入现代VCO技术的发展时期。各种VCO技术的寿命期与时间的关系示于图l。该图简要地说明了VCO技术在过去80多年里的发展历程。
图1 各种VCO技术寿命期
变容二极管、电容器、电感器等元器件的小型化为制造VCO组件创造了条件。VCO组件是一种混合集成电路器件，具有封装和外引线。虽然分立元件的晶体管VCO具有按用户要求设计工作频率和调谐范围的灵活性，但一般在生产中都需要耗费大量的人工对确定频率的元件进行调试，以消除元件误差对频率的影响。此外，分立元件VCO需要良好的屏蔽，其尺寸也比较大。分立元件的VCO已不能完全满足现代无线电子系统发展的要求。
20世纪80年代末、90年代初，移动电话迅速发展，对带封装的振荡器组件的需求也日益增长。这为VCO组件的发展提供了难得的市场机遇。随着新型无线应用领域的不断发展，各VCO组件厂商开发了适合不同应用领域所需频率的产品。由于表面安装元件的不断小型化(1206，0805，0603，0402和0201)，新开发的VCO组件的尺寸也越来越小，成本也越来越低。图2说明了现代商用VCO 组件尺寸随时间减小的变化情况。目前，VCO组件达到了新的水平，其体积已减小到4 mm×5mm×2mm，大批量供货VCO的销售单价已降至1美元左右。VCO 组件在15年中其尺寸急剧减小，满足了蜂窝电话等新型无线移动装置对小型化的要求。
VCO组件体积变化过程图2
20世纪90年代末期，出现了一种尺寸更小、成本更低的VCO技术，这就是单片集成VCO技术。单片集成VCO是一种半导体集成电路器件，其全部电路元件均集成在同一芯片上。这种器件像VCO组件一样，是一个完整的VCO，具有封装和外引线。首批单片集成VCO采用2英寸GaAs IC工艺和单片微波集成电路(MMIC)技术制造，是为卫星接收机和雷达系统研制的。其工作频率高达数GHz，但成本高昂。大多数早期单片GaAs VCO的研究工作都是针对军事应用展开的，很少涉及民用领域。在20世纪80年代，Si-IC技术还是一种低频技术，不能为单片集成VCO提供上千兆赫兹的工作频率和所需的带宽。
经过研究与开发，1990年Si-IC技术在高频化和无源元件集成方面获得重大进展，开发成功工作频率很高的晶体管、变容二极管和单片集成的高Q值电感器与高频电容器。这为高频硅单片集成VCO的研究与开发奠定了技术基础。无线移动通信系统的发展，要求大批量提供成本低、体积小、工作在800～2500MHz频段的VCO。人们为此开展了大量的研究与开发工作。1992年，美国California大学首先报道了硅单片VCO IC的研究成果。其后，对硅单片VCO IC 的研究进入繁荣期，采用不同技术方案的硅单片VCO IC相续问世。
硅单片VCO IC由高频双极晶体管IC技术和SiCMOS-IC技术研制而成。在硅单片VCO IC的研制过程中，学术研究机构通常采用获得广泛应用的SiCMOS-IC技术，而工业界则采用RFIC专用的BiCMOS技术。硅单片集成VCO 体积更小、成本更低并适合大批量生产的产品，而且可以采用RF收发前端的工艺技术进行制造。这表明，VCO可以与混频器、低噪声放大器、锁相环等其他
RF收发前端的功能电路模块实现集成。正是由于VCO IC具备这些潜在的优势，尽管早期产品性能欠佳，但人们对它的研究工作一直没有停顿。通过不断改进，其产品已广泛应用于无绳电话、蓝牙装置、WLAN、GPS、DBS等无线装置与系统之中。表1列出了一些单片集成VCO的应用实例。
表1 含有单片集成VCO的商用RFIC实例
目前，单片集成VCO还不能用于对相位噪声要求很高的应用领域。像GSM、CDMA等具有高数据速率的移动电话系统，还只能使用VCO组件。
2.2 VCO技术的发展趋势
今后，VCO技术的研究与开发工作将继续围绕VCO组件和单片集成VCO 展开。但是，全集成单片VCO技术是研究工作的重点，也是未来VCO技的发展方向为了适应现代无线系统发展的要求，VCO组件不断向小型、高频、宽带、高输出化和特性多样化方向发展。将采用新的超小型元件和更先进的薄膜技术与表面安装技术，继续推进VCO组件封装的微型化和表面安装化。通过晶体管的改进及振荡电路的开发，解决好小型化带来的谐振器Q值降低的问题和低功耗引起的特性劣化问题。第四代移动电话以及其他工作在微波频段高端的无线系统
需要VCO组件进一步提高工作频率，实现VCO组件高频化。开发工作频率更高的微波VCO组件是未来十分重要的研究课题。
SiGe BiCMOS等RF IC基础工艺技术正在不断发展与进步。半导体工艺制造有源器件与无源器件将具有更好的性能。现在，即使用Si工艺技术，也可制得超过50GHZ的晶体管和高Q值，大电容变比，低串联电阻的优质便容二极管。这类工艺技术还具有衬底损耗低，金属化层厚，器件寄生元件少，工作频率高，工作电流小的单片集成VCO。
现代无线系统，尤其是现代无线移动通信系统，不仅要求VCO自身小型化和低成本化，而且希望VCO能同频率合成器与收发机的其他单元电路进行单片集成，以达到减少整机体积和成本的目的。此外，单片集成VCO的设计理论也在深化，设计技术也越来越先进。差分放大器，幅度控制，二次谐波抑制器，IC 耦合变压器，复合振荡器，高频结构设计等技术正不断被纳入单片集成VCO的设计之中。利用单片集成VCO技术把优质VCO同收发机电路集成在一起的新产品不断问世。例如在WLAN和蓝牙装置中，最新的收发机就把高质量的VCO 同RF收发前端IC集成在一起，使其尺寸大大减小。WLAN系统（2.4GHZ 802.11b型和5GHZ 802.11a型）要求VCO具有很低的相位噪声。
由于RF IC VCO技术的不断发展，卫星接收机，CATV机顶盒，无线数据装置，无绳电话，移动电话等商用RF系统与装置越来越多地采用集成化频率源。显然，在大规模商业应用领域中，单片集成VCO占有的市场份额将不断增大，而分立元件VCO和VCO组件占有市场将逐步减小。单片集成VCO在大规模商用无线系统中占主导地位的时代很快就会到来。VCO技术已经实现了从笨重的电电子管VCO电路到面积小于1平方毫米Si IC的跨越。
3. 总结
VCO是频率源的关键器件，已广泛应用于各种电子系统之中。VCO的性能对电子系统有决定性的影响。现代无线移动通信系统的发展促进VCO高频化，形成了新一代微波VCO。VCO组件和单片集成VCO是微波VCO的主要结构形
式，是目前无线系统采用的主流产品。虽然，在总体性能水平方面，单片集成VCO目前还不如VCO组件好，但它具有集成优势，仍然是VCO未来发展的方向。在RF IC工艺技术中，SiGe BiCMOS技术是单片集成VCO最有前途的制造技术。
摘自：ISO/IEC JTC1/SC29/WG1 (ITU-SG8) N2058, "JPEG2000 is now an International Standard", 9 March 2001.
voltage controlled oscillator
1Preface
Voltage controlled oscillator ( voltage-controlled oscillator, VCO ) is a kind of voltage input to control the oscillation frequency of the oscillating circuit, is a modern radio communication system is an important part of task [1] [2]. In the integrated circuit to the smaller size, less power consumption, higher frequency, lower price trends, application standard process design and production of high performance voltage controlled oscillator RF integrated circuit is an important subject in the. The ring oscillator is easy to be integrated, the adjustable frequency range, but better performance than LC oscillator phase noise. LC VCO requirements quality factors of passive devices, need the on-chip inductor and varactor devices to integrate [3].
Oscillator since its birth has been in communication, electronics, aerospace and other fields of medicine navigation plays an important role, has a wide range of uses. In radio technology in the initial stage of development, it is in the transmitter to generate high frequency carrier wave voltage, the heterodyne receiver is used as a local oscillator, a transmitting and receiving equipment basic components. With the rapid development of electronic technology, the oscillator uses more and more widely, for example in radio measurement instruments, it produces various frequency sinusoidal signal voltage: in the heat processing, heat treatment, ultrasonic machining and some medical equipment, it produces high power high frequency electric power
of load heating; some electrical equipment oscillator. The contactless switch control; electronic clock and electronic watches using frequency stability high oscillation circuit as a timing component. Especially in the communication system circuit, a voltage controlled oscillator ( VCO ) is one of the key parts, especially in the
phase-locked loop circuit, clock recovery circuit and frequency synthesizer circuit is Chongzhongzhi is heavy, it is no exaggeration to say in electronic communication technology, VCO almost with the current source and the operational amplifier has the same important position.
2.theme
2.1The development of 1.VCO process
At the beginning of the last century, Armstrong invented electronic oscillator, the improved Hartley circuit design and the successful development of VCO tube. Electronic tube VCO oscillation frequency is changed by the oscillation circuit inductor or capacitor parameter values to adjust. At that time the people to the electronic tube oscillation circuit to carry out a great deal of research, today is still in use in the Hartley, Colpitts, Clapp, Armstrong, Pierce and other classical oscillating circuit structure, was the research results.
The middle of the last century, the first transistor and quickly replace the tube becomes oscillatory circuit of the active device. In particular the varactor applications on the VCO has important significance to the development of. Variable capacitance diode capacitance as a function of the applied voltage change, using varactor diode voltage controlled device, change the control voltage can be achieved VCO oscillation frequency regulation. In this way, the transistor, varactor diodes and other passive components form the vertical transistor VCO. This transistor VCO implementation of the oscillation frequency of the electronic tuning varactor diode, it is the significant contribution of VCO development. Electronic tube with VCO compared to VCO, transistor with electronic tuning, small volume, low cost, small power consumption, good quality, easy FM range setting. Transistor VCO is the development of television technology at that time rapid promotion of important reasons. From 1960 to1980, VCO transistors are widely used in electronic system design. By 1980, the situation
has changed, hybrid integrated VCO module and monolithic integrated VCO IC appeared. These two kinds of new technology to the development of VC0has produced important influence. VCO has started to enter the modern VCO technology development period. A variety of VCO technology life cycle and the time relation shown in Figure L. The graph, a brief description of the VCO technology in the past 80 years development course.
Fig 1VCO technology life cycle
Variable capacitance diodes, capacitors, inductors and other components of the miniaturization for the manufacture of VCO components to create the conditions. VCO component is a hybrid integrated circuit device, a package and the outer lead wires. Although discrete transistor VCO according to user requirements with the design and operating frequency tuning range and flexibility, but generally in the production need to consume a large amount of artificial to determine the frequency components for debugging, in order to eliminate the element error on the frequency effect. In addition, discrete components VCO needs good shielding, its size is relatively large. Discrete element VCO can not satisfy the requirements of the development of modern wireless electronic system.
At the end of nineteen eighties, the early 90's, the rapid development of the mobile phone, with a package of oscillator components growing demand. This is a VCO component development offerred rare market opportunity. Along with the new wireless application development, each VCO component manufacturers developed for
different applications in the field of desired frequency products. Due to the small surface mount components (1206080506030402 and0201), the new development of the VCO component size is more and more small, cost more and more low. Figure 2 illustrates the modern commercial VCO component size with reduced variation. At present, the VCO component has reached a new level, its volume is reduced to 4mm * 5mm * 2mm, supply large quantities VCO sales price has dropped to about $1. VCO component in the15 years of its size reduced sharply, to meet the new wireless mobile devices such as cellular phones on the miniaturization requirement.
The VCO component volume change process of2 Nineteen ninties stage, the emergence of a smaller size, lower cost of the VCO technology, which is monolithically integrated VCO technology. Monolithic integrated VCO is a semiconductor integrated circuit device, all the circuit components are integrated on the same chip. This device like the VCO module, is a complete VCO, with packaging and outer lead. The first batch of monolithic integrated VCO uses 2 inches of GaAs IC technology and the monolithic microwave integrated circuit ( MMIC ) manufacturing technology, is for the satellite receiver and radar system. Its high working frequency of GHz, but the high cost. Most of the early single GaAs VCO 's research work is aimed at the military application of unfolding, rarely involved in civil field. In the nineteen eighties, Si-IC technology is a kind of low frequency technology, not for the monolithic integrated VCO with Giga Hertz frequency and bandwidth required for.
Through research and development, in 1990 the Si-IC technique in high frequency and passive components integration has achieved significant progress, the successful development of the work with very high frequency transistor, variable capacitance diode and monolithic integration of high Q value of the inductor and the high frequency capacitor. The high frequency silicon monolithic integrated VCO research and development laid a technological basis. Wireless mobile communication system development, requirements in large quantities to provide low cost, small volume, work in the 800 ~2500MHz band VCO. It carried out a great deal of research and development work. In 1992, American California University was first reported by Silicon Monolithic VCO IC research. Thereafter, the silicon monolithic VCO IC research to enter prosperous period, using different techniques for Silicon Monolithic VCO IC continued publication.
Silicon Monolithic VCO IC by high frequency bipolar transistor IC technology and SiCMOS-IC technology developed by. In Silicon Monolithic VCO IC development process, academic and research institutions usually adopt the widely used SiCMOS-IC technology, while the industry is using RFIC special BiCMOS technology. Silicon monolithic integrated VCO smaller volume, lower cost and suitable for mass production of products, but also can be used to RF front-end technology manufacturing. This shows, VCO can be associated with a mixer, low noise amplifier, phase locked loop and other RF front-end circuit function module to realize the integrated. It is because the VCO IC with these potential advantages, although early products of poor performance, but the research work has not stopped. Through continuous improvement, its products have been widely used in cordless phones, Bluetooth devices, WLAN, GPS, DBS and other wireless devices and systems. Table 1 lists some monolithic integrated VCO application examples [4].
Table 1 contains monolithic integrated VCO RFIC commercial examples
At present, monolithic integrated VCO also cannot be used for phase noise of demanding applications. Like GSM, CDMA has a high data rate mobile phone system, also can use VCO components
2.2The development trend of 2.VCO Technology
In the future, VCO technology research and development work will continue to focus on VCO components and monolithic integrated VCO expansion. However, the monolithic integrated VCO technology is the research focus, but also the future of VCO technology development direction in order to adapt to modern wireless system development requirements, VCO components to small, high frequency, wide band, high output and characteristic development. We will adopt a new miniature components and more advanced thin film technology and surface mount technology, continue to promote the VCO package miniaturization and mounted on the surface of. The pass transistor oscillation circuit improvement and development, solve good miniaturization brings resonator Q reduces problems and low power consumption caused by deterioration of a problem. Fourth generation mobile phones and other work in the microwave band high-end wireless systems need to further improve the working frequency of the VCO component, VCO component high frequency. Development of frequency higher microwave VCO components are very important research topic in the future.
SiGe BiCMOS RF IC basic technology is evolving with progress. Semiconductor manufacturing technology of active devices and passive components will have better performance. Now, using the Si technology, also can be used for more than 50GHZ transistors and high Q value, high capacitance ratio, low series resistance and capacitance diode quality. This technology also has a substrate of low loss, metal layer thickness of parasitic element, device is little, high working frequency, small working current monolithic integrated VCO.
Modern wireless systems, especially in modern mobile communication system, not only requires the VCO its miniaturization and low cost, but also hope that VCO with frequency synthesizer and transceiver unit circuits are monolithically integrated, so as to reduce the volume and cost of the. In addition, monolithic integrated VCO design theory also is being deepened, more and more advanced design technology. Differential amplifier, amplitude control, two harmonic suppressor, IC coupling transformer, composite oscillator, high frequency structure design technology are being incorporated into the monolithic integrated VCO design. Using monolithic integrated VCO technology to high-quality VCO transceiver circuit integrated together with the new products continue to come out. For example, in WLAN and Bluetooth device, the new transceiver is made of high quality VCO and RF transceiver front-end IC integrated together, so that its size is greatly reduced. WLAN (2.4GHZ802.11b type and 5GHZ type 802.11a ) called VCO has very low phase noise.
Because RF IC VCO technology unceasing development, satellite receiver, CATV set-top box, wireless data device, cordless phones, mobile phones and other commercial RF systems and devices are increasingly used integrated frequency source. Obviously, in large-scale commercial application, monolithic integrated VCO market share will continue to increase, and the discrete component VCO and VCO components of market share will be reduced stage by stage. Monolithic integrated VCO in large-scale commercial wireless system is dominated by the time will soon
come. VCO technology has realized from the heavy electric tube VCO circuit to the area less than 1square mm Si IC span.
3.summary
VCO is the key device of frequency source, has been widely used in various electronic systems. The performance of VCO has a decisive effect on electronic system. In modern mobile communication system to promote the development of VCO high frequency, to form a new generation of microwave VCO. The VCO components and VCO microwave monolithic integrated VCO is a main structural form, is currently the mainstream product of wireless system. Although, in the overall performance levels, monolithic integrated VCO is inferior to VCO component, but it has the integrated advantage, VCO still is the developing direction in the future [5]. In the RF IC technology, SiGe BiCMOS technology is a monolithic integrated VCO the most promising manufacturing technology.
外国语学院2018届毕业论文文献综述（示范） 一、研究背景 近来多篇论文中出现零翻译的提法（杜争鸣，2000；邱懋如，2001；刘明东，2002；袁斌业，2002a，2002b，2002c，2002d；石琳，2003；余清萍，2003；余清萍，秦傲松，2004；肖耀田，2004），但国内学者所编三本译学词典（林煌天，1997；孙迎春，1999；方梦之，2004）均未出现零翻译这一词条，国外三本词典/术语著作（Shuttleworth & Cowie，1997；Baker，1998；Delisle，2004）亦未收入这一条目，只有国内孙迎春（2001）编著的《汉英双向翻译学语林》收进了“零翻译（音译、形译之一种）zero translation”（58页）及“zero translation零翻译（音译、形译之一种）”（268页）两个条目，同时又有贾影（2002）反对零翻译提法，并认为承认不可译有“积极作用”。但零翻译现象确实存在，如DIY（自己动手），IQ（智商），EQ（情商），这些零翻译词汇经常在汉语中出现。英语中也有类似情况，如美国《时代》周刊中报道中国特色事物时经常使用拼音，如aizi(矮子)，pizi（痞子），shiganjia（实干家），yuan（缘）（王祥兵，2002），shuangying(双赢)，guanxi(关系)（顾静，2005）。 这些研究成果揭示了零翻译现象的存在，引进了零翻译的概念，促进了翻译理论概念的扩大，但是从发表的论文及孙迎春（2001）的这两个条目来看，各自运用的名称虽同（也有不同，如杜争鸣称为不译），但概念的内涵及外延均有出入，因此有必要探讨当前零翻译研究的问题并提出相应研究对策。 二、研究现状及不足 1. 定义不统一、模糊不清 传统翻译理论多把零翻译归结为“音译法”、“移译法”，只看到技巧层面的意义，如秦建栋（1999）讨论“英汉词汇空缺现象刍议”列举“音译法”、“移译法”，袁斌业（2001）论及“英语本族人音译汉语词汇的语用分析”，虽然看到“音译在我国只能用来翻译名词，而在国外则可以用来翻译包括名词在内的各种词语”，但未能从中提炼出零翻译的概念，实际上这里已包含有零翻译与音译的某些区别。 国内最早使用zero translation这一术语的是杜争鸣（2000），但他称之为“不译”，并分析了直译、意译与不译三种翻译策略。他不停留于策略本身，从跨文化交际的视角分析了三种策略的社会语言学与跨文化交际涵义，并看到了不译的三层文化含义。不译背后体现译者对于翻译目的的认识，“而翻译的目的必然直接或间接地反映反映译者本人对翻译的文化含义的意识与潜意识，反映他翻译时所采取的文化姿态与立场。”即翻译观的问题。但从术语的精确性来说
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。
文献综述怎么写 1) 什么是文献综述? 文献综述是研究者在其提前阅读过某一主题的文献后，经过理解、整理、融会贯通，综合分析和评价而组成的一种不同于研究论文的文体。 2) 文献综述的写作要求 1、文献综述的格式 文献综述的格式与一般研究性论文的格式有所不同。这是因为研究性的论文注重研究的方法和结果，而文献综述介绍与主题有关的详细资料、动态、进展、展望以及对以上方面的评述。因此文献综述的格式相对多样，但总的来说，一般都包含以下四部分：即前言、主题、总结和参考文献。撰写文献综述时可按这四部分拟写提纲，再根据提纲进行撰写工作。 前言，要用简明扼要的文字说明写作的目的、必要性、有关概念的定义，综述的范围，阐述有关问题的现状和动态，以及目前对主要问题争论的焦点等。前言一般200-300字为宜，不宜超过500字。 正文，是综述的重点，写法上没有固定的格式，只要能较好地表达综合的内容，作者可创造性采用诸多形式。正文主要包括论据和论证两个部分，通过提出问题、分析问题和解决问题，比较不同学者对同一问题的看法及其理论依据，进一步阐明问题的来龙去脉和作者自己的见解。当然，作者也可从问题发生的历史背景、目前现状、发展方向等提出文献的不同观点。正文部分可根据内容的多少可分为若干个小标题分别论述。 小结，是结综述正文部分作扼要的总结，作者应对各种观点进行综合评价，提出自己的看法，指出存在的问题及今后发展的方向和展望。内容单纯的综述也可不写小结。 参考文献，是综述的重要组成部分。一般参考文献的多少可体现作者阅读文献的广度和深度。对综述类论文参考文献的数量不同杂志有不同的要求，一般以30条以内为宜，以最近3-5年内的最新文献为主。 2、文献综述规定 1. 为了使选题报告有较充分的依据，要求硕士研究生在论文开题之前作文献综述。 2. 在文献综述时，研究生应系统地查阅与自己的研究方向有关的国内外文献。通常阅读文献不少于30篇，且文献搜集要客观全面 3. 在文献综述中，研究生应说明自己研究方向的发展历史，前人的主要研究成果，存在的问题及发展趋势等。 4. 文献综述要条理清晰，文字通顺简练。 5. 资料运用恰当、合理。文献引用用方括号[ ]括起来置于引用词的右上角。 6. 文献综述中要有自己的观点和见解。不能混淆作者与文献的观点。鼓励研究生多发现问题、多提出问题、并指出分析、解决问题的可能途径，针对性强。 7. 文献综述不少于3000字。 3、注意事项 ⒈搜集文献应尽量全。掌握全面、大量的文献资料是写好综述的前提，否则，随便搜集一点资料就动手撰写是不可能写出好的综述。 ⒉注意引用文献的代表性、可靠性和科学性。在搜集到的文献中可能出现观点雷同，有的文献在可靠性及科学性方面存在着差异，因此在引用文献时应注意选用代表性、可靠性和科学性较好的文献。 ⒊引用文献要忠实文献内容。由于文献综述有作者自己的评论分析，因此在撰写时应分清作者的观点和文献的内容，不能篡改文献的内容。引用文献不过多。文献综述的作者引用间接文献的现象时有所见。如果综述作者从他人引用的参考文献转引过来，这些文献在他人
Heavy Oil Development Technology of Liaohe Oilfield Han Yun (Scientific Research Information Department Exploration&Development Research Institute，Liaohe Oilfield Company) Liaohe Oilfield，the largest heavy oil production base in China，features in various reservoir types，deep burial，and wide range of crude oil viscosity．For many years，a series of technologies have been developed for different oil products and reservoir types of the oilfield，of which water flooding，foam slug drive，steam stimulation，steam drive,and SAGD are the main technologies. After continuous improvement，they have been further developed and played an important role in the development of heavy oil in the oilfield． Liaohe Oilfield is abundant in heavy oil resources，46％of the total proved reserves of Liaohe Oilfield Company. Horizontally the resources concentrates in the West Depression and the southern plunging belt of the Central Uplift in Liaohe Rift. Vertically,it is mainly distributed in Paleocene Shahejie Formation(ES). The distinctive geological feature of Liaohe 0ilfield is manifested in three aspects：first，the heavy oil reservoirs are deeply buried and 80％of them are buried more than 900m deep；second，the heavy oil viscosity ranges widely．For most of the reservoirs．the dead oil viscosity ranges in 100～100000mPa·s with the maximum 650000mPa·s.Third the reservoir types are various with complicated oil—water relationship，most of the reservoirs are edge water and bosom water reservoirs and there are also edge water reservoirs，top water reservoirs and bosom water reservoirs．For more than 20 years of development，Liaohe Oilfield has developed series of heavy oil development technologies for different oil products and different types of reservoirs，such as water flooding, foam slug drive,steam stimulation steam drive and SAGD．The most difficult issues have been overcome in the development of the super
新闻英语翻译研究文献综述 新闻英语，即“新闻报道文章中所使用的英语,具有新闻特性、适合新闻报道要求、适应新闻信息传播需要的语言”（张建，2004），成为了对外宣传的重要工具，特别是进入新世纪以来，对新闻翻译这一领域的关注日益增强，近年来，我国学者关于这方面的研究也逐渐逐渐多元化，从现有文献来看，主要集中在新闻本身的文体特点及翻译方法、新闻翻译理论、新闻翻译原则等方面。 1 新闻文体特点及翻译方法的研究文献综述 徐泉、王婷（2001）总结出新闻文体的如下特点：1.用词新颖，精巧别致；2.句式多样富于弹性；3.巧用时态，布局呼应；4.频繁使用被动语态，重点突出；5.结构合理层次分明；6.善用修辞，讲求效果。就语法层面的翻译而言,李侠（2004）分析了英语新闻句子的四大特点：1.信息量大；2.结构简单； 3.语法手段丰富；4.名词修饰语前置。李认为在翻译英语新闻时,必须遵循汉英两种语言的规律和使用习惯,努力增强译作的准确性和可读性,并提出了英语新闻句子汉译的3种方法: 1.化长为短； 2.调整句子中各部分的顺序与敢减敢删；3.使用四字格结构。曾尼（2010）从新闻英语的标题、词汇和时态及语态的角度，论述了新闻英语的一些文体特征。比如，由于报刊篇幅有限，新闻事件在语法方面的一个重要特点就是句型的高度扩展，结构严谨，句式简短精练，语言简洁是受人们称赞并为人们所追求的风格。郑连勋、郑堃（2011）认为新闻英语的问题与其他形式的新闻问题相同，拥有许多属于自己的独特语言。在理解其用词特点的基础上面，代词、复合词、外来词等应用方式，也是新闻英语用词方面的关键，从英语新闻报道展开分析，以借代词、引申词、复合词、外来词、小词语缩略词、临时造词等方面为例探讨了英语新闻当中的用词特点。 不少学者就这些文体特点的翻译进行了单项阐述。王治江（2001）提出了新闻外来词语音译中应注意的原则，即人名和地名中翻译要统一，不仅要译出指称意义，还要译出联想意义，但要避免产生贬义联想。范晓航（2003）
文献综述 大学生时间管理研究——以郑州大学西亚斯国际学院为例 姓名：代永寒学号：20091211205 专业：工商管理班级：工本2班 史蒂芬?柯维的《要事第一》 “要事第一”，顾名思义是指重要的主要的事情要放在第一时间去完成。而在实际工作中我们往往是将认为急迫的紧要的事情放在第一时间完成； 本书通过四个象限来告诉我们如何区分事情的紧急性与重要性，从而告诉我们在平常的工作中应怎样去区分事情属轻属重，以及造成事情紧急性的原因，在平常工作中要注意哪些方面以避免出现紧急事件的情况。 第一象限包括四点：A危机 B 急迫的问题C最后期限迫近的项目 D 会议准备工作等。第一象限显得紧迫与重要，但我们要知道形成第一象限的紧迫与重要主要是因被延误及没有进行计划与预测及计划所致。第二象限包含准备工作、预防、价值、筹划、建立关系、真正的再创造与赋予能力。第二象限属于质量象限，属于重要但不紧迫的事情，但我们必须要去做，因只有这样才能避免出现第一象限包含的情况。第三象限包含干扰、电话；邮件、报告；某些会议；很多临近、急迫的事情及很多流行的活动。第三象限包括“紧急但不重要的事情”，而事实上它易给人造成假象，从而形成第一象限情况。第四象限包含琐事、打发时间的工作、某些电话，解闷，“逃避”行为、无关紧要的邮件及过多地看电视；第四象限属于既不紧急也不重要的事情，它是浪费象限，第四象限中的行为是堕落行为。这四个象限告诉我们如果在办事过程中不是以重要性而是以紧要性为出发点，就会出现第一第三甚至第四象限的情况，在平常的工作中，我们要加以区分，日常工作生活中往往事情越是紧迫，反而说明事情越不重要！像最近存货系统因急着想能早日上线，在运作过程中被卡住，故一心想着去解决软件中存在的问题，而忽略了与其他人员的沟通协调，存货上软件固然重要，但与公司整体运作相比就稍显其次，没合理分配其他人员手头事项，这样会导致其他问题的增多，从而会出现第一第三象限甚至于第四象限的浪费情况。 “要事第一”，告诉我们在日常的工作与生活中要从以下方面着手加以区分、
New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.
中英文对照外文翻译文献 (文档含英文原文和中文翻译) OIL UNDER ICE DETECTION: WHAT IS THE STATE-OF-THE-ART? Abstract. Since the exploration for oil and gas in the Canadian and US arctic commenced in the early 1970s, a need has been identified to develop technology to detect oil under ice. Both electromagnetic and acoustic sensors have been tried, but a practical field instrument has not been identified. Most proposed systems require that the equipment be operated from the ice surface in order to get adequate coupling and, for some systems, the snow must be removed from the ice. For many ice
situations, surface access is difficult and poses a severe safety issue. Two recent spills in Alberta used “high technology” ice augers to detect the presence of oil under the ice. Some potential new techniques are discussed and the basic principles of their operation described. Keywords: arctic, oil spill response, oil in ice, detection 1. Introduction The detection of oil under continuous ice cover has presented one of the most difficult challenges to the oil-spill technological community for the past two decades and there is still no operationally proven system available. Dickins (2000) under the sponsorship of the US Minerals Management Service conducted an excellent review of the status of oil-under-ice detection and this paper complements this review with a more detailed analysis of some systems. Dickins identified many false start concepts, which will not be discussed in this paper. In order to determine the design of a suitable oil-under-ice detector, the various situations under which oil may be found under a continuous ice sheet need to be considered. The oil must come from a sub-surface release since any surface release would either be on the ice surface or in a lead or other opening in the ice. Potential sources of sub-surface oil are a leak in a pipeline, the leakage from a submerged tank or vessel or a natural seep. Oil when trapped under ice does not spread rapidly or cover a large area due to natural
开题报告、文献综述、外文翻译、论文反抄袭软件、论文目录，就差论文正文了，其他都全了！！ 开题报告主要包括以下几个方面： （一）论文名称 论文名称就是课题的名字 第一，名称要准确、规范。准确就是论文的名称要把论文研究的问题是什么，研究的对象是什么交待清楚，论文的名称一定要和研究的内容相一致，不能太大，也不能太小，要准确地把你研究的对象、问题概括出来。 第二，名称要简洁，不能太长。不管是论文或者课题，名称都不能太长，能不要的字就尽量不要，一般不要超过20个字。 （二）论文研究的目的、意义 研究的目的、意义也就是为什么要研究、研究它有什么价值。这一般可以先从现实需要方面去论述，指出现实当中存在这个问题，需要去研究，去解决，本论文的研究有什么实际作用，然后，再写论文的理论和学术价值。这些都要写得具体一点，有针对性一点，不能漫无边际地空喊口号。主要内容包括：⑴研究的有关背景(课题的提出)：即根据什么、受什么启发而搞这项研究。⑵通过分析本地（校）的教育教学实际，指出为什么要研究该课题，研究的价值，要解决的问题。 （三）本论文国内外研究的历史和现状（文献综述）。 规范些应该有，如果是小课题可以省略。一般包括：掌握其研究的广度、深度、已取得的成果；寻找有待进一步研究的问题，从而确定本课题研究的平台(起点)、研究的特色或突破点。 （四）论文研究的指导思想 指导思想就是在宏观上应坚持什么方向，符合什么要求等，这个方向或要求可以是哲学、政治理论，也可以是政府的教育发展规划，也可以是有关研究问题的指导性意见等。 （五）论文写作的目标 论文写作的目标也就是课题最后要达到的具体目的,要解决哪些具体问题，也就是本论文研究要达到的预定目标：即本论文写作的目标定位，确定目标时要紧扣课题,用词要准确、精练、明了。 常见存在问题是：不写研究目标；目标扣题不紧；目标用词不准确；目标定得过高, 对预定的目标没有进行研究或无法进行研究。 确定论文写作目标时，一方面要考虑课题本身的要求，另一方面要考率实际的工作条件与工作水平。 （六）论文的基本内容 研究内容要更具体、明确。并且一个目标可能要通过几方面的研究内容来实现，他们不一定是一一对应的关系。大家在确定研究内容的时候，往往考虑的不是很具体，写出来的研究内容特别笼统、模糊，把写作的目的、意义当作研究内容。 基本内容一般包括：⑴对论文名称的界说。应尽可能明确三点：研究的对象、研究的问题、研究的方法。⑵本论文写作有关的理论、名词、术语、概念的界说。 （七）论文写作的方法 具体的写作方法可从下面选定：观察法、调查法、实验法、经验总结法、个案法、比较研究法、文献资料法等。 （八）论文写作的步骤 论文写作的步骤，也就是论文写作在时间和顺序上的安排。论文写作的步骤要充分考虑研究
附录 图像科学综述 近几年来，图像处理与识别技术得到了迅速的发展，现在人们己充分认识到图像处理和识别技术是认识世界、改造世界的重要手段。目前它己应用于许多领域，成为2l世纪信息时代的一门重要的高新科学技术。 1.图像处理与识别技术概述 图像就是用各种观测系统以不同形式和手段观测客观世界而获得的，可以直接或间接作用于人眼而产生视知觉的实体。科学研究和统计表明，人类从外界获得的信息约有75%来自于视觉系统，也就是说，人类的大部分信息都是从图像中获得的。 图像处理是人类视觉延伸的重要手段，可以便人们看到任意波长上所测得的图像。例如，借助伽马相机、x光机，人们可以看到红外和超声图像：借助CT可看到物体内部的断层图像；借助相应工具可看到立体图像和剖视图像。1964年，美国在太空探索中拍回了大量月球照片，但是由于种种环境因素的影响，这些照片是非常不清晰的，为此，美国喷射推进实验室(JPL)使用计算机对图像进行处理，使照片中的重要信息得以清晰再现。这是这门技术发展的重要里程碑。此后，图像处理技术在空间研究方面得到广泛的应用。 总体来说，图像处理技术的发展大致经历了初创期、发展期、普及期和实用化期4个阶段。初创期开始于20世纪60年代，当时的图像采用像素型光栅进行扫描显示，大多采用巾、大型机对其进行处理。在这一时期，由于图像存储成本高，处理设备造价高，因而其应用面很窄。20世纪70年代进入了发展期，开始大量采用中、小型机进行处理，图像处理也逐渐改用光栅扫描显示方式，特别是出现了CT和卫星遥感图像，对图像处理技术的发展起到了很好的促进作用。到了20世纪80年代，图像处理技术进入普及期，此时购微机已经能够担当起图形图像处理的任务。VLSL的出现更使得处理速度大大提高，其造价也进一步降低，极大地促进了图形图像系统的普及和应用。20世纪90年代是图像技术的实用化时期，图像处理的信息量巨大，对处理速度的要求极高。 21世纪的图像技术要向高质量化方面发展，主要体现在以下几点：①高分辨率、高速度，图像处理技术发展的最终目标是要实现图像的实时处理，这在移动
英文翻译 A comprehensive overview of substations Along with the economic development and the modern industry developments of quick rising, the design of the power supply system become more and more completely and system. Because the quickly increase electricity of factories, it also increases seriously to the dependable index of the economic condition, power supply in quantity. Therefore they need the higher and more perfect request to the power supply. Whether Design reasonable, not only affect directly the base investment and circulate the expenses with have the metal depletion in colour metal, but also will reflect the dependable in power supply and the safe in many facts. In a word, it is close with the economic performance and the safety of the people. The substation is an importance part of the electric power system, it is consisted of the electric appliances equipments and the Transmission and the Distribution. It obtains the electric power from the electric power system, through its function of transformation and assign, transport and safety. Then transport the power to every place with safe, dependable, and economical. As an important part of power’s transport and control, the transformer substation must change the mode of the traditional design and control, then can adapt to the modern electric power system, the development of modern industry and the of trend of the society life. Electric power industry is one of the foundations of national industry and national economic development to industry, it is a coal, oil, natural gas, hydropower, nuclear power, wind power and other energy conversion into electrical energy of the secondary energy industry, it for the other departments of the national economy fast and stable development of the provision of adequate power, and its level of development is a reflection of the country's economic development an important indicator of the level. As the power in the industry and the importance of the national economy, electricity transmission and distribution of electric energy used in these areas is an indispensable component.。Therefore, power transmission and distribution is critical. Substation is to enable superior power plant power plants or power after adjustments to the lower load of books is an important part of power transmission. Operation of its functions, the capacity of a direct impact on the size of the lower load power, thereby affecting the industrial production and power consumption.Substation system if a link failure, the system will protect the part of action. May result in power outages and so on, to the production and living a great disadvantage. Therefore, the substation in the electric power system for the protection of electricity reliability,
一、激励理论的背景 在经济发展的过程中,劳动分工与交易的出现带来了激励问题。激励理论是行为科学中用于处理需要，动机，目标和行为四者之间关系的核心理论。行为科学认为人的动机来自需要，由需要确定人们的行为目标，激励则作用于人内心活动，激发，驱动和强化人的行为。哈佛大学维廉詹姆士研究表明：在没有激励措施下,下属一般仅能发挥工作能力的20%～30%，而当他受到激励后,其工作能力可以提升到80%～90%，所发挥的作用相当于激励前的3到4倍。日本丰田公司采取激励措施鼓励员工提建议，结果仅1983年一年，员工提了165万条建议，平均每人31条，它为公司带来900亿日元利润，相当于当年总利润的18%。由于激励的效果明显，所以各种组织为了提高生产效率，有些专家学者就开始了对激励理论的研究之中，探索激励的无穷潜力。 二、国外研究现状 国外对于激励理论有了大量的研究并获得了丰硕的成果。总体来说，可以分为两类激励理论。一类是以人的心理需求和动机为主要研究对象的激励理论，熟称“内容型激励理论”。另一类是以人的心理过程和行为过程相互作用的动态系统为研究对象的激励过程理论,它也被称作是“行为型激励理论”。 1 内容型激励理论 1.1 奠瑞的人类人格理论 这种理论认为，在面临着动态且不断变化的环境时，人们都是自适应的。它把需求分成了两种类型，即生理需求和心理需求。前者与人体基本生理过程的满足感有关，而后者所关注的是情绪上和精神上的满足感。 1.2 马斯洛的“需要层次”理论 美国心理学家马斯洛(A.H.Maslow)进一步发展了莫瑞的研究，在1954年出版的《动机与人格》一书中对该理论作了进一步的阐释。马斯洛认为人的需要可以划分为五个层次，从低到高依次为生理需要，安全需要，社交需要，尊熏需要，自我实现需要，且这五个层次的顺序，对每个人都是相同的。只有当较低层次的需要获得了基本满足后，下一个较高层次的需要才能成为主导需要。 1.3 赫茨伯格的激励—保健双因素理论 美国心理学家赫茨伯格因素理论打破了这一假设。他于1959年在《工作的激励》一书中提出了保健——激励因素理论，简称双因素理论。即保健因素和激励因素。保健因素可以用来体现高水平员工的不满意，激励因素可以用来体现高水平员工的满意度。他认为只有激励因素才能促发员工积极性,提高生产效率。 2 行为型激励理论 2.1 洛克的目标设置理论 2O世纪6O年代末，埃德温·A·洛克和他的同事们花了许多年的时间研究目标对于人类行为和绩效的效果。他们的研究导致了目标设置理论的创立并不断地得到验证，提出：指向一共同目标的工作意向是工作效率的主要源泉。他还提出了具体的设置目标的步骤。 2.2 亚当斯的公平理论 美国心理学家亚当斯(J.s.Adams)对员工受激励程度的大小与他人之间的关系进行研究，并在《工人关于工资不公平的内心冲突同其生产率的关系》(1962年与罗森合写)，《工
at89c52单片机简介 中英文资料对照外文翻译文献综述 A T89C52 Single-chip microprocessor introduction Selection of Single-chip microprocessor 1. Development of Single-chip microprocessor The main component part of Single-chip microprocessor as a result of by such centralize to be living to obtain on the chip，In immediate future middle processor CPU。Storage RAM immediately﹑memoy read ROM﹑Interrupt system、Timer /'s counter along with I/O's rim electric circuit awaits the main microcomputer section，The lumping is living on the chip。Although the Single-chip microprocessor r is only a chip，Yet through makes up and the meritorous service be able to on sees，It had haveed the calculating machine system property，calling it for this reason act as Single-chip microprocessor r minisize calculating machine SCMS and abbreviate the Single-chip microprocessor。 1976Year the Inter corporation put out 8 MCS－48Set Single-chip microprocessor computer，After being living more than 20 years time in development that obtain continuously and wide-ranging application。1980Year that corporation put out high performance MCS －51Set Single-chip microprocessor。This type of Single-chip microprocessor meritorous service capacity、The addressing range wholly than early phase lift somewhat，Use also comparatively far more at the moment。1982Year that corporation put out the taller 16 Single-chip microprocessor MCS of performance once
第一篇： 航空博物馆与航空展示公园 巴特罗米耶杰·基谢列夫斯基 飞翔的概念、场所的精神、老机场的建筑---克拉科夫新航空博物馆理性地吸取了这些元素，并将它们整合到一座建筑当中。Rakowice-Czyzyny机场之前的旧飞机修理库为新建筑的平面和高度设定了模数比例。在此基本形态上进一步发展，如同裁切和折叠一架纸飞机，生成了一座巨大的建筑。其三角形机翼是由混凝土制成，却如同风动螺旋桨一样轻盈。这个机翼宽大通透，向各个方向开敞。它们的形态与组织都是依据内部功能来设计的。机翼部分为3个不平衡的平面，使内外景观在不断变化中形成空间的延续性，并且联系了建筑内的视觉焦点和室外的展览区。 新航空展示公园的设计连接了博物馆的8栋建筑和户外展览区，并与历史体验建立联系。从前的视觉轴线与通道得到尊重，旧的道路得到了完善，朝向飞机场和跑道的空间被限定出来。每栋建筑展示了一个主题或是一段飞行史。建筑周围伸展出巨大的平台，为特殊主题的室外展览提供了空间。博物馆容纳了超过150架飞机、引擎、飞行复制品、成套的技术档案和历史图片。这里的特色收藏是飞机起源开始的各种飞行器，如Jatho1903、Grade1909、莱特兄弟1909年的飞机模型和1911年的鸽式单翼机。 The first passage: Museum for aviation and aviation exhibition park Bartiomiej Kislelewski The idea of flying, the spirit of place, the structure of the historic airfield – the new Museum of Aviation in Krakow takes up these references intellectually and synthesizes them into a building. The old hangars of the former airport Rakowice Czyzyny set the modular scale for the footprint and the height of the new building. Developed from this basic shape, as if cut out and folded like a paper airplane, a large structure has been generated, with triangular wings made of concrete and yet as light as a wind-vane propeller. The wings are generously glazed and open in all directions. Their form and arrangement depend on the interior uses. In the floor plans of the wings, the three offset