本科毕业设计
外文文献及译文
文献、资料题目：Designing Stable Control Loops 文献、资料来源：期刊
文献、资料发表（出版）日期：2010.3.25院（部）：信息与电气工程学院
专业：电子信息工程
班级：电信B124
姓名：尚营军
学号：201203014414
指导教师：黄成玉
翻译日期：2016.5.10
外文文献：
Designing Stable Control Loops
The objective of this topic is to provide the designer with a practical review of loop compensation techniques applied to switching power supply feedback control. A top-down system approach is taken starting with basic feedback control concepts and leading to step-by-step design procedures, initially applied to a simple buck regulator and then expanded to other topologies and control algorithms. Sample designs are demonstrated with Math cad simulations to illustrate gain and phase margins and their impact on performance analysis.
I. I NTRODUCTION
Insuring stability of a proposed power supply solution is often one of the more challenging aspects of the design process. Nothing is more disconcerting than to have your lovingly crafted breadboard break into wild oscillations just as its being demonstrated to the boss or customer, but insuring against this unfortunate event takes some analysis which many designers view as formidable. Paths taken by design engineers often emphasize either cut-and-try empirical testing in the laboratory or computer simulations looking for numerical solutions based on complex mathematical models. While both of these approach a basic understanding of feedback theory will usually allow the definition of an acceptable compensation network with a minimum of computational effort.
II. S TABILITY D EFINED
Fig. 1. Definition of stability
Fig. 1 gives a quick illustration of at least one definition of stability. In its simplest terms, a system is stable if, when subjected to a perturbation from some source, its response to that perturbation eventually dies out. Note that in any practical system, instability cannot result in a completely unbounded response as the system will either reach a saturation level –or fail. Oscillation in a switching regulator can, at most, vary the duty cycle between zero and 100% and while that may not prevent failure, it wills ultimate limit the response of an unstable system. Another way of visualizing stability is shown in Fig. 2. While this graphically illustrates the concept of system stability, it also points out that we must make a further distinction between large-signal and small-signal stability. While small-signal stability is an important and necessary criterion, a system could satisfy thisrt quirement and yet still become unstable with a large-signal perturbation. It is important that designers remember that all the gain and phase calculations we might perform are only to insure small-signal stability. These calculations are based upon – and only applicable to –linear systems, and a switching regulator is – by definition – a non-linear system. We solve this conundrum by performing our analysis using small-signal perturbations around a large-signal operating point, a distinction which will be further clarified in our design procedure discussion。
Fig. 2. Large-signal vs. small-signal stability
III. F EEDBACK C ONTROL P RINCIPLES
Where an uncontrolled source of voltage (or current, or power) is applied to the input of our system with the expectation that the voltage (or current, or power) at the output will be very well
controlled. The basis of our control is some form of reference, and any deviation between the output and the reference becomes an error. In a feedback-controlled system, negative feedback is used to reduce this error to an acceptable value –as close to zero as we want to spend the effort to achieve. Typically, however, we also want to reduce the error quickly, but inherent with feedback control is the tradeoff between system response and system stability. The more responsive the feedback network is, the greater becomes the risk of instability. At this point we should also mention that there is another method of control –feedforward.With feed forward control, a control signal is developed directly in response to an input variation or perturbation. Feed forward is less accurate than feedback since output sensing is not involved, however, there is no delay waiting for an output error signal to be developed, andfeedforward control cannot cause instability. It should be clear that feed forward control will typically not be adequate as the only control method for a voltage regulator, but it is often used together with feedback to improve a regulator’s response to dynamic input variations.
The basis for feedback control is illustrated with the flow diagram of Fig. 3 where the goal is for the output to follow the reference predictably and for the effects of external perturbations, such as input voltage variations, to be reduced to tolerable levels at the output Without feedback, the reference-to-output transfer function y/u is equal to G, and we can express the output asy Gu With the addition of feedback (actually the subtraction of the feedback signal)
y Gu yHG
and the reference-to-output transfer function becomes
y/u=G/1+GH
If we assume that GH __ 1, then the overall transfer function simplifies to
y/u=1/H
Fig. 3. Flow graph of feedback control
Not only is this result now independent of G,it is also independent of all the parameters of the system which might impact G (supply voltage, temperature, component tolerances, etc.) and is determined instead solely by the feedback network H (and, of course, by the reference).Note that the accuracy of H (usually resistor tolerances) and in the summing circuit (error amplifier offset voltage) will still contribute to an output error. In practice, the feedback control system, as modeled in Fig. 4, is designed so thatG __ H and GH __ 1 over as wide a frequency range as possible without incurring instability. We can make a further refinement to our generalized power regulator with the block diagram shown in Fig. 5. Here we have separated the power system into two blocks – the power section and the control circuitry. The power section handles the load current and is typically large, heavy, and subject to wide temperature fluctuations. Its switching functions are by definition, large-signal phenomenon, normally simulated in most stability analyses as just a two states witch with a duty cycle. The output filter is also considered as a part of the power section but can be considered as a linear block.
Fig. 4. The general power regulator
IV. T HE B UCK C ONVERTER
The simplest form of the above general power regulator is the buck –or step down –topology whose power stage is shown in Fig. 6. In this configuration, a DC input voltage is switched at some repetitive rate as it is applied to an output filter. The filter averages the duty cycle modulation of the input voltage to establish an output DC voltage lower than the input value.The transfer function for this stage is defined by
tON=switch on -time
T = repetitive period (1/fs)
d = duty cycle
Fig. 5. The buck converter.
Since we assume that the switch and the filter components are lossless, the ideal efficiency of
T his conversion process is 100%, and regulation of the output voltage level is achieved by controlling the duty cycle. The waveforms of Fig.6 assume a continuous conduction mode (CCM)
M eaning that current is always flowing through the inductor – from the switch when it is closed,
A nd from the diode when the switch is open. The analysis presented in this topic will emphasize CCM operation because it is in this mode that small-signal stability is generally more difficult
to achieve. In the discontinuous conduction mode (DCM), there is a third switch condition in which the inductor, switch, and diode currents are all 5-4 zero. Each switching period starts from the same state (with zero inductor current), thus effectively reducing the system order by one and making small-signal stable performance much easier to achieve. Although beyond the scope of this topic, there may be specialized instances where the large-signal stability of a DCM system is of greater concern than small-signal stability.
There are several forms of PWM control for the buck regulator including,
? Fixed frequency (fS) with variable tON and variable tOFF
? Fixed tON with variable tOFF and variable fS
? Fixed tOFF with variable tON and variable fS
? Hysteretic (or “b ang-bang”) with tON, tOFF,and fS all variable
Each of these forms have their own set of advantages and limitations and all have been successfully used, but since all switch mode regulators generate a switching frequency component and its associated harmonics as well as the intended DC output, electromagnetic interference and noise considerations have made fixed frequency operation by far the most popular.
With the exception of hysteretic, all other forms of PWM control have essentially the same small-signal behavior. Thus, without much loss in generality, fixed fS will be the basis for our discussion of classical, small-signal stability.
Hysteretic control is fundamentally different in that the duty factor is not controlled, per se. Switch turn-off occurs when the output ripple voltage reaches an upper trip point and turn-on occurs at a lower threshold. By definition, this is
a large-signal controller to which small-signal stability considerations do not apply. In a small signal sense, it is already unstable and, in a mathematical sense, its fast response is due more to feed forward than feedback.
R EFERENCES
[1] D. M. Mitchell, “DC-DC Switching Regulator Analysis”, McGraw-Hill, 1988,
DMMitchell Consultants, Cedar Rapids, IA, 1992(reprint version).
[2] D. M. Mitchell, “Small-Signal Mathcad Design Aids”, (Windows 95 / 98 version), e/j BLOOM Associates, Inc., 1999.
[3] George Chryssis, “High-Frequency Switching Power Supplies”, McGraw-Hill Book Company, 1984.
[4] Ray Ridley, “A More Accurate Current- Mode Control Model”, Unitrode Seminar Handbook, SEM-1300, Appendix A2.
[5] Lloyd Dixon, “Control Loop Design”, Unitrode Seminar Handbook, SEM-800.
[6] Lloyd Dixon, “Control Loop Design –SEPIC Preregulator Design”, Unitrode Seminar Handbook, SEM-900, Topic 7.
[7] Lloyd Dixon, “Closing the Feedback Loop”, Unitrode Seminar Handbook, SEM-300.
中文翻译：
控制电路设计
摘要：
本篇论文的写作目的，是为给设计师们提供一个实际性的说明，那就是线性补偿技术在电源转换与电流反馈操作中是如何应用的。一个组织管理严密的系统电路需要一开始就有一个基础的电流反馈操作理论的支持，并且通过一步步的设计步骤，从初步阶段应用到一个简单升压调节器，然后再扩展到其他的拓扑学与算数控制学中去。matchad模拟器也验证了设计样本中幅相裕度整定在分布设计中是存在的，并且还影响着实验的分析报告。一、简介：
验证所提议的电源供给解决方案的稳定性，一直就是电路设计过程中一个极具挑战性的方面。最让你感到窘迫的，并不是你最为得意之作的电路板正在实验的重要阶段中，被突然闯入的无序振荡所打乱，而是你实验恰恰验证了许多电路设计者感到最为头疼的数据分析。电路设计师常常强调，在实验室里要注重切换实验的实用价值，或者是以复杂的数学模式为电脑集成系统所需要的数据处理。然而这两者的方向都是以电路设计的前提为基
础。于是，对反馈原理最基本的理解将帮助我们去定义接受性补偿网系统的最小值计算范围。
二、稳定性的界定：
图1 稳定的定义
图1直接展示了至少一个关于稳定性的界定。用最简洁的术语来说，如果一个电路系统是稳定的，就算被从某些来源说产生的微扰所压制时，返回的微扰的也将会一并抵消。需要注意的是，在任何实用电路中，不稳定性不会导致一个完全无束缚的反应，这就如同电路既会达到饱和状态——也会处于缺损状态一样。正在调节器转化过程中的振荡极有可能在零和百分之一百间的负荷周期中波动，并且这种变化不可能阻止失败，它将最终制约不稳定电路的回流电。
图2 展示的是另外一个设想的稳定性。尽管该图形象地展示了电路稳定性的观点，但与此同时，也指出了我们必须将大信号的稳定性与小信号的稳定性严格区分开来。然而小信号的稳定性是一个非常重要和非常需要的判断标准，一个电路也可以满足这个要求，并且会与一个大信号的微扰一起变得不稳定。重要的是，电路设计师们需要记得，所有我们可能执行的幅相裕度整定计算仅仅只是确保了小信号的稳定性。这些计算结果主要依靠——并且只适用于——线性电路，和一个转换调节器——被定义为——非线性的电路。我们通过用围绕小信号直流工作点周围小信号的微扰，来演算我们的分析结果，去解决这个迷团。这之中的具体差别将会在接下来的设计过程的有关探讨来说明。
图2 强信号和弱信号
三、反馈电流控制原理：
展示的是一个最基本的调节器，在这里，不受控制的电压来源（或者电流，或者功率）将会被应用到电路的输入，且在输出过程中被这个不受控制的电压（电流或者功率）的预期值完全的掌控。电流控制的基础是一些基准电压的结构，任何在输出电流和基准电压之间的偏差都是会导致电路的错误。在一个反馈操作电路中，负反馈回流电是用来减少在可接受的标准内这种错误——就如我们希望能从一开始付出努力，一直坚持到最后能成功一样。然而，按照典型的案例来说，我们也希望让错误不会那么快的发生，但是回流电控制电路本身就存在着频率响应与电路稳定性的互换。回流电路的频率响应越多，不稳定的危险性就越大。
在这一点上我们应该注意，另外一个控制方法——前反馈。通过前反馈的控制，一个控制信号将被直接地发展到去回应一个输出波动或者微扰中。前反馈没有回流电那么精准，因为检测输出电流不是那么复杂难懂，然而，无法否认的是，等待一个输出电流的错误信号会被发现，而且前反馈控制无法产生不稳定性。需要清楚表明的是，典型的前反馈控制将不像只有一个电压调节器的控制线路那么有效，但是前反馈的控制经常被用于和反馈一起去加快调节器对动态输入变动的响应频率。
图3中的电流图阐述了反馈控制的基础，目标就是为了输出功率能跟着可以预测的基准电压，为了将外部微扰的影响，如同输出功率的变动一样，能会被减少到输出功率所能接
受的等级上。
图3 反馈控制流图
如果没有反馈电，基准电压到输出功率的转换函数y/u就跟G是一样的，我们可以这样表达输出功率：
y=Gu
另外反馈电流（实际上是反馈信号的减法）：
y Gu yHG
之后r基准电压与输出功率的转换函数：
Y=G
u=1 GH
如果我们假设GH=1，那么整体的转换函数就是：
y/u=1/h
这个函数不仅使得G现在成为独立，它还使所有的电路参数都变得独立，这这可能会影响G（供给功率、温度、元件公差，等等）并且被只被回流电路H（并且，理所当然的，被基准电压作用）所代替来决定它。值得一提的是，H的准确性（通常称为电阻的公差）和电路的总和（错误放大补偿功率）将继续造成输出电流的错误。在实际中，反馈控制电路，如图4的模型所示，如此设计是为了使G ：H和GH=1的振动频率能越大范围越好并且不会产生任何不稳定性。
我们可以进一步的改良概括功率调节器就像图4所见到的一样。在这里我们有单独分开的功率系统进去到两个板块——功率段和控制电路。功率段处理电流的负荷，并且功率段通常是大、重、经历广阔的温度范围波动。它的转换功能被定义为，大信号现象，通常在最稳定的分析结果中进行模拟，就像在负荷周期中的两极转换一样。输出电流过滤器被当做为线性板块。控制电路通常有一个增长板块——错误发大器——和宽脉冲波调幅器所组成，用来定义电压转换。
图4 一般电源稳压
四、降压转换器：
上述一般动力的最简单形式降压稳压器- 或降压- 拓扑它的功率级，如图6所示在这配置，直流输入电压起动，有些重复率，因为它是适用于输出过滤器。该过滤器的占空比平均输入电压的调制建立输出直流电压比输入值低。变量的传递函数定义如下
其中
tON为开关时间
T 为重复周期（频率的倒数）
D为占空比
图5.降压转换器
由于我们假设开关和过滤器组件是无损的，理想的效率这个转换过程是100％，与规制输出电压的水平是通过控制占空比。在波形图。6假设连续传导模式（CCM）这意味着电流始终流经当它从封闭开关- 电感从二极管当开关处于打开状态。该在这个主题提出的分析会强调CCM工作，因为正是在这一模式小信号稳定，一般比较困难来实现。在非连续导通模式（DCM）的，有三分之一的开关状态，其中电感器，开关和二极管电流都为零。每个开关周期开始从同一状态（零电感电流），从而有效地该系统减少了一个顺序，使小信号性能稳定，更容易实现。虽然超出了本专题的范围，可能有专门的情况是，大信号的DCM 系统的稳定性是更令人关注的比小信号稳定。
也有几种形式的PWM控制降压稳压器，包括
?固定频率和开关变量
?修正开的变量和变量频率关变量
?可变开和变量频率固定关变量
?迟滞与开、关频率变量，
所有的变量和fS这些形式各有各的一套优势和局限性，并已全部成功使用，但因为所有的开关模式监管机构产生的开关频率组件及其相关谐波以及如预期的直流输出，电磁干扰和噪声问题作出迄今为止最固定频率操作受欢迎。
随着滞后，所有其他异常PWM控制形式基本上相同小信号的行为。因此，没有太多的损失在一般性的，固定的fS将是我们的基础讨论古典，小信号稳定。滞回控制是根本不同的在该职责的因素得不到控制，本身。开关关断时，会发生输出纹波电压达到一个上限触发点和开启发生在一个较低的门槛。根据定义，这是一大信号控制器的小信号稳定的考虑并不适用。在小信号某种意义上说，它已经是不稳定的，并且在一数学意义上，它更快速的反应，是由于比前馈反馈。
参考文献
[1]米切尔四米，“DC - DC开关调节分析”，麦格劳希尔，1988年，DMMitchell顾问，锡达拉皮兹，保险业监督，1992年（重印版）。
[2]四米米切尔，“小信号的Mathcad设计辅助“，（视窗95 / 98版），电子/日本布卢姆Associates公司，1999。
[3]乔治Chryssis，“高频交换式电源供应“，麦格劳希尔预订公司，1984。
[4]雷里德利“一个更精确的电流模式控制模式“，Unitrode研讨会手册，扫描电镜- 1300，附录A2。
[5]劳埃德迪克逊，“控制回路设计“，Unitrode研讨会手册，扫描电镜- 800。
[6]劳埃德迪克逊，“控制回路设计 -SEPIC型前置稳压器设计“，Unitrode研讨会手册，扫描电镜- 900，题目7。
吉林化工学院理学院 毕业论文外文翻译English Title（Times New Roman ，三号） 学生学号：08810219 学生姓名：袁庚文 专业班级：信息与计算科学0802 指导教师：赵瑛 职称副教授 起止日期：2012.2.27～2012.3.14 吉林化工学院 Jilin Institute of Chemical Technology
1 外文翻译的基本内容 应选择与本课题密切相关的外文文献（学术期刊网上的），译成中文，与原文装订在一起并独立成册。在毕业答辩前，同论文一起上交。译文字数不应少于3000个汉字。 2 书写规范 2.1 外文翻译的正文格式 正文版心设置为：上边距：3.5厘米，下边距：2.5厘米，左边距：3.5厘米，右边距：2厘米，页眉：2.5厘米，页脚：2厘米。 中文部分正文选用模板中的样式所定义的“正文”，每段落首行缩进2字；或者手动设置成每段落首行缩进2字，字体：宋体，字号：小四，行距：多倍行距1.3，间距：前段、后段均为0行。 这部分工作模板中已经自动设置为缺省值。 2.2标题格式 特别注意：各级标题的具体形式可参照外文原文确定。 1．第一级标题（如：第1章绪论）选用模板中的样式所定义的“标题1”，居左；或者手动设置成字体：黑体，居左，字号：三号，1.5倍行距，段后11磅，段前为11磅。 2．第二级标题（如：1.2 摘要与关键词）选用模板中的样式所定义的“标题2”，居左；或者手动设置成字体：黑体，居左，字号：四号，1.5倍行距，段后为0，段前0.5行。 3．第三级标题（如：1.2.1 摘要）选用模板中的样式所定义的“标题3”，居左；或者手动设置成字体：黑体，居左，字号：小四，1.5倍行距，段后为0，段前0.5行。 标题和后面文字之间空一格（半角）。 3 图表及公式等的格式说明 图表、公式、参考文献等的格式详见《吉林化工学院本科学生毕业设计说明书（论文）撰写规范及标准模版》中相关的说明。
Inventory management Inventory Control On the so-called "inventory control", many people will interpret it as a "storage management", which is actually a big distortion. The traditional narrow view, mainly for warehouse inventory control of materials for inventory, data processing, storage, distribution, etc., through the implementation of anti-corrosion, temperature and humidity control means, to make the custody of the physical inventory to maintain optimum purposes. This is just a form of inventory control, or can be defined as the physical inventory control. How, then, from a broad perspective to understand inventory control? Inventory control should be related to the company's financial and operational objectives, in particular operating cash flow by optimizing the entire demand and supply chain management processes (DSCM), a reasonable set of ERP control strategy, and supported by appropriate information processing tools, tools to achieved in ensuring the timely delivery of the premise, as far as possible to reduce inventory levels, reducing inventory and obsolescence, the risk of devaluation. In this sense, the physical inventory control to achieve financial goals is just a means to control the entire inventory or just a necessary part; from the perspective of organizational functions, physical inventory control, warehouse management is mainly the responsibility of The broad inventory control is the demand and supply chain management, and the whole company's responsibility. Why until now many people's understanding of inventory control, limited physical inventory control? The following two reasons can not be ignored: First, our enterprises do not attach importance to inventory control. Especially those who benefit relatively good business, as long as there is money on the few people to consider the problem of inventory turnover. Inventory control is simply interpreted as warehouse management, unless the time to spend money, it may have been to see the inventory problem, and see the results are often very simple procurement to buy more, or did not do warehouse departments . Second, ERP misleading. Invoicing software is simple audacity to call it ERP, companies on their so-called ERP can reduce the number of inventory, inventory control, seems to rely on their small software can get. Even as SAP, BAAN ERP world, the field of
Statistical hypothesis testing Adriana Albu，Loredana Ungureanu Politehnica University Timisoara,adrianaa@aut.utt.ro Politehnica University Timisoara,loredanau@aut.utt.ro Abstract In this article,we present a Bayesian statistical hypothesis testing inspection, testing theory and the process Mentioned hypothesis testing in the real world and the importance of, and successful test of the Notes. Key words Bayesian hypothesis testing; Bayesian inference;Test of significance Introduction A statistical hypothesis test is a method of making decisions using data, whether from a controlled experiment or an observational study (not controlled). In statistics, a result is called statistically significant if it is unlikely to have occurred by chance alone, according to a pre-determined threshold probability, the significance level. The phrase "test of significance" was coined by Ronald Fisher: "Critical tests of this kind may be called tests of significance, and when such tests are available we may discover whether a second sample is or is not significantly different from the first."[1] Hypothesis testing is sometimes called confirmatory data analysis, in contrast to exploratory data analysis. In frequency probability,these decisions are almost always made using null-hypothesis tests. These are tests that answer the question Assuming that the null hypothesis is true, what is the probability of observing a value for the test statistic that is at [] least as extreme as the value that was actually observed?) 2 More formally, they represent answers to the question, posed before undertaking an experiment,of what outcomes of the experiment would lead to rejection of the null hypothesis for a pre-specified probability of an incorrect rejection. One use of hypothesis testing is deciding whether experimental results contain enough information to cast doubt on conventional wisdom. Statistical hypothesis testing is a key technique of frequentist statistical inference. The Bayesian approach to hypothesis testing is to base rejection of the hypothesis on the posterior probability.[3][4]Other approaches to reaching a decision based on data are available via decision theory and optimal decisions. The critical region of a hypothesis test is the set of all outcomes which cause the null hypothesis to be rejected in favor of the alternative hypothesis. The critical region is usually denoted by the letter C. One-sample tests are appropriate when a sample is being compared to the population from a hypothesis. The population characteristics are known from theory or are calculated from the population.
毕业论文（设计）外文翻译 题目：中国上市公司偏好股权融资：非制度性因素 系部名称：经济管理系专业班级:会计082班 学生姓名：任民学号： 200880444228 指导教师：冯银波教师职称:讲师 年月日
译文： 中国上市公司偏好股权融资：非制度性因素 国际商业管理杂志 2009.10 摘要：本文把重点集中于中国上市公司的融资活动，运用西方融资理论，从非制度性因素方面，如融资成本、企业资产类型和质量、盈利能力、行业因素、股权结构因素、财务管理水平和社会文化，分析了中国上市公司倾向于股权融资的原因，并得出结论，股权融资偏好是上市公司根据中国融资环境的一种合理的选择。最后，针对公司的股权融资偏好提出了一些简明的建议。 关键词：股权融资，非制度性因素，融资成本 一、前言 中国上市公司偏好于股权融资，根据中国证券报的数据显示，1997年上市公司在资本市场的融资金额为95.87亿美元，其中股票融资的比例是72.5％，，在1998年和1999年比例分别为72.6％和72.3％，另一方面，债券融资的比例分别是17.8％，24.9％和25.1％。在这三年，股票融资的比例，在比中国发达的资本市场中却在下跌。以美国为例，当美国企业需要的资金在资本市场上，于股权融资相比他们宁愿选择债券融资。统计数据显示，从1970年到1985年，美日企业债券融资占了境外融资的91.7％，比股权融资高很多。阎达五等发现，大约中国3/4的上市公司偏好于股权融资。许多研究的学者认为，上市公司按以下顺序进行外部融资：第一个是股票基金，第二个是可转换债券，三是短期债务，最后一个是长期负债。许多研究人员通常分析我国上市公司偏好股权是由于我们国家的经济改革所带来的制度性因素。他们认为，上市公司的融资活动违背了西方古典融资理论只是因为那些制度性原因。例如，优序融资理论认为，当企业需要资金时，他们首先应该转向内部资金（折旧和留存收益），然后再进行债权融资，最后的选择是股票融资。在这篇文章中，笔者认为，这是因为具体的金融环境激活了企业的这种偏好，并结合了非制度性因素和西方金融理论，尝试解释股权融资偏好的原因。
农村社会养老保险的现状、问题与对策研究社会保障对国家安定和经济发展具有重要作用，“城乡二元经济”现象日益凸现，农村社会保障问题客观上成为社会保障体系中极为重要的部分。建立和完善农村社会保障制度关系到农村乃至整个社会的经济发展，并且对我国和谐社会的构建至关重要。我国农村社会保障制度尚不完善，因此有必要加强对农村独立社会保障制度的构建，尤其对农村养老制度的改革，建立健全我国社会保障体系。从户籍制度上看，我国居民养老问题可分为城市居民养老和农村居民养老两部分。对于城市居民我国政府已有比较充足的政策与资金投人，使他们在物质和精神方面都能得到较好地照顾，基本实现了社会化养老。而农村居民的养老问题却日益突出，成为摆在我国政府面前的一个紧迫而又棘手的问题。 一、我国农村社会养老保险的现状 关于农村养老，许多地区还没有建立农村社会养老体系，已建立的地区也存在很多缺陷，运行中出现了很多问题，所以完善农村社会养老保险体系的必要性与紧迫性日益体现出来。 （一）人口老龄化加快 随着城市化步伐的加快和农村劳动力的输出，越来越多的农村青壮年人口进入城市，年龄结构出现“两头大，中间小”的局面。中国农村进入老龄社会的步伐日渐加快。第五次人口普查显示：中国65岁以上的人中农村为5938万，占老龄总人口的67.4%.在这种严峻的现实面前，农村社会养老保险的徘徊显得极其不协调。 （二）农村社会养老保险覆盖面太小 中国拥有世界上数量最多的老年人口，且大多在农村。据统计，未纳入社会保障的农村人口还很多，截止2000年底，全国7400多万农村居民参加了保险，占全部农村居民的11.18%，占成年农村居民的11.59%.另外，据国家统计局统计，我国进城务工者已从改革开放之初的不到200万人增加到2003年的1.14亿人。而基本方案中没有体现出对留在农村的农民和进城务工的农民给予区别对待。进城务工的农民既没被纳入到农村养老保险体系中，也没被纳入到城市养老保险体系中，处于法律保护的空白地带。所以很有必要考虑这个特殊群体的养老保险问题。
软件专业毕业论文外文文献中英文翻译 Object landscapes and lifetimes Tech nically, OOP is just about abstract data typing, in herita nee, and polymorphism, but other issues can be at least as importa nt. The rema in der of this sect ion will cover these issues. One of the most importa nt factors is the way objects are created and destroyed. Where is the data for an object and how is the lifetime of the object con trolled? There are differe nt philosophies at work here. C++ takes the approach that con trol of efficie ncy is the most importa nt issue, so it gives the programmer a choice. For maximum run-time speed, the storage and lifetime can be determined while the program is being written, by placing the objects on the stack (these are sometimes called automatic or scoped variables) or in the static storage area. This places a priority on the speed of storage allocatio n and release, and con trol of these can be very valuable in some situati ons. However, you sacrifice flexibility because you must know the exact qua ntity, lifetime, and type of objects while you're writing the program. If you are trying to solve a more general problem such as computer-aided desig n, warehouse man ageme nt, or air-traffic con trol, this is too restrictive. The sec ond approach is to create objects dyn amically in a pool of memory called the heap. In this approach, you don't know un til run-time how many objects you n eed, what their lifetime is, or what their exact type is. Those are determined at the spur of the moment while the program is runnin g. If you n eed a new object, you simply make it on the heap at the point that you n eed it. Because the storage is man aged dyn amically, at run-time, the amount of time required to allocate storage on the heap is sig ni fica ntly Ion ger tha n the time to create storage on the stack. (Creat ing storage on the stack is ofte n a si ngle assembly in structio n to move the stack poin ter dow n, and ano ther to move it back up.) The dyn amic approach makes the gen erally logical assumpti on that objects tend to be complicated, so the extra overhead of finding storage and releas ing that storage will not have an importa nt impact on the creati on of an object .In additi on, the greater flexibility is esse ntial to solve the gen eral program ming problem. Java uses the sec ond approach, exclusive". Every time you want to create an object, you use the new keyword to build a dyn amic in sta nee of that object. There's ano ther issue, however, and that's the lifetime of an object. With Ian guages that allow objects to be created on the stack, the compiler determines how long the object lasts and can automatically destroy it. However, if you create it on the heap the compiler has no kno wledge of its lifetime. In a Ianguage like C++, you must determine programmatically when to destroy the
本科毕业设计（论文）中英文对照翻译 院（系部）电气工程与自动化 专业名称电子信息工程 年级班级 04级7班 学生姓名 指导老师
Infrared Remote Control System Abstract Red outside data correspondence the technique be currently within the scope of world drive extensive usage of a kind of wireless conjunction technique,drive numerous hardware and software platform support. Red outside the transceiver product have cost low, small scaled turn, the baud rate be quick, point to point SSL, be free from electromagnetism thousand Raos etc.characteristics, can realization information at dissimilarity of the product fast, convenience, safely exchange and transmission, at short distance wireless deliver aspect to own very obvious of advantage.Along with red outside the data deliver a technique more and more mature, the cost descend, red outside the transceiver necessarily will get at the short distance communication realm more extensive of application. The purpose that design this system is transmit cu stomer’s operation information with infrared rays for transmit media, then demodulate original signal with receive circuit. It use coding chip to modulate signal and use decoding chip to demodulate signal. The coding chip is PT2262 and decoding chip is PT2272. Both chips are made in Taiwan. Main work principle is that we provide to input the information for the PT2262 with coding keyboard. The input information was coded by PT2262 and loading to high frequent load wave whose frequent is 38 kHz, then modulate infrared transmit dioxide and radiate space outside when it attian enough power. The receive circuit receive the signal and demodulate original information. The original signal was decoded by PT2272, so as to drive some circuit to accomplish
毕业论文外文资料翻译题目(宋体三号，居中) 学院(全称，宋体三号，居中) 专业(全称，宋体三号，居中) 班级(宋体三号，居中) 学生(宋体三号，居中) 学号(宋体三号，居中) 指导教师(宋体三号，居中) 二〇一〇年月日(宋体三号，居中，时间与开题时间一致)
（英文原文装订在前）
Journal of American Chemical Society, 2006, 128(7): 2421-2425. (文献翻译必须在中文译文第一页标明文献出处：即文章是何期刊上发表的，X年X 卷X期，格式如上例所示，四号，右对齐，杂志名加粗。) [点击输入译文题目-标题1，黑体小二] [点击输入作者，宋体小四] [点击输入作者单位，宋体五号] 摘要[点击输入，宋体五号] 关键词[点击输入，宋体五号] 1[点击输入一级标题-标题2，黑体四号] [点击输入正文，宋体小四号，1.25倍行距] 1.1[点击输入二级标题-标题3，黑体小四] [点击输入正文，宋体小四，1.25倍行距] 1.1.1[点击输入三级标题-标题4，黑体小四] [点击输入正文，宋体小四，1.25倍行距] 说明： 1.外文文章必须是正规期刊发表的。 2.翻译后的中文文章必须达到2000字以上，并且是一篇完整文章。 3.必须要有外文翻译的封面，使用学校统一的封面； 封面上的翻译题目要写翻译过来的中文题目； 封面上时间与开题时间一致。 4.外文原文在前，中文翻译在后； 5.中文翻译中要包含题目、摘要、关键词、前言、全文以及参考文献，翻译要条理
清晰，中文翻译要与英文一一对应。 6.翻译中的中文文章字体为小四，所有字母、数字均为英文格式下的，中文为宋体， 标准字符间距。 7.原文中的图片和表格可以直接剪切、粘贴，但是表头与图示必须翻译成中文。 8.图表必须居中，文章段落应两端对齐、首行缩进2个汉字字符、1.25倍行距。 例如： 图1. 蛋白质样品的PCA图谱与8-卟啉识别排列分析(a)或16-卟啉识别排列分析(b)。为了得到b 的 数据矩阵，样品用16-卟啉识别排列分析来检测，而a 是通过捕获首八卟啉接收器数据矩阵从 b 中 萃取的。
Real-time interactive optical micromanipulation of a mixture of high- and low-index particles Peter John Rodrigo, Vincent Ricardo Daria and Jesper Glückstad Optics and Plasma Research Department, Ris? National Laboratory, DK-4000 Roskilde, Denmark jesper.gluckstad@risoe.dk http://www.risoe.dk/ofd/competence/ppo.htm Abstract: We demonstrate real-time interactive optical micromanipulation of a colloidal mixture consisting of particles with both lower (n L < n0) and higher (n H > n0) refractive indices than that of the suspending medium (n0). Spherical high- and low-index particles are trapped in the transverse plane by an array of confining optical potentials created by trapping beams with top-hat and annular cross-sectional intensity profiles, respectively. The applied method offers extensive reconfigurability in the spatial distribution and individual geometry of the optical traps. We experimentally demonstrate this unique feature by simultaneously trapping and independently manipulating various sizes of spherical soda lime micro- shells (n L≈ 1.2) and polystyrene micro-beads (n H = 1.57) suspended in water (n0 = 1.33). ?2004 Optical Society of America OCIS codes: (140.7010) Trapping, (170.4520) Optical confinement and manipulation and (230.6120) Spatial Light Modulators. References and links 1. A. Ashkin, “Optical trapping and manipulation of neutral particles using lasers,” Proc. Natl. Acad. Sci. USA 94, 4853-4860 (1997). 2. K. Svoboda and S. M. Block, “Biological applications of optical forces,” Annu. Rev. Biophys. Biomol. Struct. 23, 247-285 (1994). 3. D. G. Grier, “A revolution in optical manipulation,” Nature 424, 810-816 (2003). 4. M. P. MacDonald, G. C. Spalding and K. Dholakia, “Microfluidic sorting in an optical lattice,” Nature 426, 421-424 (2003). 5. J. Glückstad, “Microfluidics: Sorting particles with light,” Nature Materials 3, 9-10 (2004). 6. A. Ashkin, “Acceleration and trapping of particles by radiation-pressure,”Phys. Rev. Lett. 24, 156-159 (1970). 7. A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm and S. Chu, “Observation of a single-beam gradient force optical trap for dielectric particles,” Opt. Lett. 11, 288-290 (1986). 8. K. Sasaki, M. Koshioka, H. Misawa, N. Kitamura, and H. Masuhara, “Optical trapping of a metal particle and a water droplet by a scanning laser beam,” Appl. Phys. Lett. 60, 807-809 (1992). 9. K. T. Gahagan and G. A. Swartzlander, “Trapping of low-index microparticles in an optical vortex,” J. Opt. Soc. Am. B 15, 524-533 (1998). 10. K. T. Gahagan and G. A. Swartzlander, “Simultaneous trapping of low-index and high-index microparticles observed with an optical-vortex trap,” J. Opt. Soc. Am. B 16, 533 (1999). 11. M. P. MacDonald, L. Paterson, W. Sibbett, K. Dholakia, P. Bryant, “Trapping and manipulation of low-index particles in a two-dimensional interferometric optical trap,” Opt. Lett. 26, 863-865 (2001). 12. R. L. Eriksen, V. R. Daria and J. Glückstad, “Fully dynamic multiple-beam optical tweezers,” Opt. Express 10, 597-602 (2002), https://www.doczj.com/doc/cb18163521.html,/abstract.cfm?URI=OPEX-10-14-597. 13. P. J. Rodrigo, R. L. Eriksen, V. R. Daria and J. Glückstad, “Interactive light-driven and parallel manipulation of inhomogeneous particles,” Opt. Express 10, 1550-1556 (2002), https://www.doczj.com/doc/cb18163521.html,/abstract.cfm?URI=OPEX-10-26-1550. 14. V. Daria, P. J. Rodrigo and J. Glückstad, “Dynamic array of dark optical traps,” Appl. Phys. Lett. 84, 323-325 (2004). 15. J. Glückstad and P. C. Mogensen, “Optimal phase contrast in common-path interferometry,” Appl. Opt. 40, 268-282 (2001). 16. S. Maruo, K. Ikuta and H. Korogi, “Submicron manipulation tools driven by light in a liquid,” Appl. Phys. Lett. 82, 133-135 (2003). #3781 - $15.00 US Received 4 February 2004; revised 29 March 2004; accepted 29 March 2004 (C) 2004 OSA 5 April 2004 / Vol. 12, No. 7 / OPTICS EXPRESS 1417
本科毕业设计 外文文献及译文 文献、资料题目：Designing Stable Control Loops 文献、资料来源：期刊 文献、资料发表（出版）日期：2010.3.25 院（部）：信息与电气工程学院 专班姓学业：电气工程与自动化级： 名： 号： 指导教师：翻译日期：2011.3.10
外文文献： Designing Stable Control Loops The objective of this topic is to provide the designer with a practical review of loop compensation techniques applied to switching power supply feedback control. A top-down system approach is taken starting with basic feedback control concepts and leading to step-by-step design procedures,initially applied to a simple buck regulator and then expanded to other topologies and control algorithms. Sample designs are demonstrated with Math cad simulations to illustrate gain and phase margins and their impact on performance analysis. I. I NTRODUCTION Insuring stability of a proposed power supply solution is often one of the more challenging aspects of the design process. Nothing is more disconcerting than to have your lovingly crafted breadboard break into wild oscillations just as its being demonstrated to the boss or customer, but insuring against this unfortunate event takes some analysis which many designers view as formidable. Paths taken by design engineers often emphasize either cut-and-try empirical testing in the laboratory or computer simulations looking for numerical solutions based on complex mathematical models.While both of these approach a basic understanding of feedback theory will usually allow the definition of an acceptable compensation network with a minimum of computational effort. II. S TABILITY D EFINED Fig. 1.Definition of stability Fig. 1 gives a quick illustration of at least one definition of stability. In its simplest terms, a system is stable if, when subjected to a perturbation from some source, its response to that