蒸汽发生器水位控制
中英文资料外文翻译文献
Research on Fuzzy Control for Steam Generator Water Level
I. INTRODUCTION
The steam generator is one of the main devices in PWR nuclear power plant, in order to ensure the safety of nuclear power plant during operation; the steam generator?s water level must be controlled in a certain range. When the nuclear power plant is running, as the steam flow or the water flow changing, the amount of boiling bubbles in the steam generator will change due to local pressure or temperature change, the instantaneous water level showed “false water level” phenomenon .The existence of “false water level” made it difficult to control the water level. The introduction of feed-forward control to the traditional single-loop PID control can, in a certain extent, overcome the "false water level" phenomenon. But the conventional PID control method in the process of steam generator water level control has some shortcomings. To the steam generator that has highly complex, large time-delay and nonlinear time-varying characteristics, the PID parameters tuning is a tedious job and the control effect is very poor. Furthermore, to achieve good control performance still as conditions changing, it often needs to change the PID controller parameters. But the analog PID controller parameters are difficult to regulate online. Fuzzy control is a kind of nonlinear control strategy based on fuzzy reasoning, which express operating experience of skilled manipulation men and common sense rules of inference through vague language. Fuzzy control do not need to know precise mathematical model of controlled object, is not sensitive to the change of process parameters, is highly robust and can overcome non-linear factors, so, fuzzy control has faster response and smaller ultra- tone, can get better control effect. Based on understanding above, this paper design a steam generator water level fuzzy controller, the simulation shows that the
controller has good control performance and practical value.
II. DYNAMIC CHARACTERISTICS OF STEAM GENERATOR
The transfer function of PWR steam generator?s mathematical model of the general form shows below:
y(s)=GW(s)QW(s)+GS(s)QS(s) （1）where y is the steam generator water level; QW for the water flow; QS for the steam flow; GW (s) for the impact of the water flow to the steam generator water level; GS (s) for the effect of the steam flow (load) to the steam generator water level.
The balance of the steam generator water level is maintained through the match between the water flow and steam flow. The process that water level changes with the steam flow or water flow changing can be regarded as a simple integration process, but impact of the water flow and steam flow …s change on water level is different.
A. Dynamics Characteristics under Water Flow Disturbance
Suppose steam flow GS remains unchanged, and water flow GW step increases, on the one hand because the temperature of feed water is much lower than the temperature of saturated water in the steam generator, so that , when feed water entering, it will absorb a lot of extra heat, the vapor phase bubble contents will reduce, resulting in water level decreasing; on the other hand, the increase in water flow GW made it greater than steam load, and cause water level increases linearly. Comprehensive two factors, after the step increase of the water flow, the water level rise has a time delay process, showing a down then up.
B. Dynamic Characteristics under Steam Load Disturbance
Suppose feed water flow GW remains unchanged, and steam load GS step increases, on the one hand the water level will flow down because the steam flow rate is greater than the water flow rate. On the other hand, as the steam load increased, vapor pressure is reduced; the bubble volume on the liquid surface increases, causing the water level increased. Comprehensive two factors, after the step increase of the steam flow rate, the water level down has a time delay process, showing a up then down.
The impact on the water level of water flow or steam flow stepping decreased has similar principle as above.
As analysis can be seen as above, when the water flow or steam load change, the water level did not follow the change immediately, but there is an opposite process at first. This phenomenon is called "false water level" phenomenon.
III. DESIGN OF W ATER LEVEL FUZZY CONTROLLER
The conventional PID controller has a poor control performance to the steam generator that exist
“false water level” characteristics, showing a greater overshoot in the tracking time. But a well-designed fuzzy controller is able to overcome the "false water level" phenomenon, and has good control performance.
A. Sstructure of Fuzzy Controller
The structure showed in Figure 1.
Figure 1. Structure of steam generator water level fuzzy controller
Choose the water level error (e) and change rate of error (ec) as input of the fuzzy controller, the output of the fuzzy controller is the added value of the valve opening signal Δu. Meanwhile, use the steam flow feed-forward to overcome the "false water level" phenomenon, use water flow feedback to overcome fluctuations in water supply side . k1, k2 were water flow and steam flow transmitter conversion factor. To ensure the water flow to match the steam flow, k1 and k2 values should be equal to.
B. Fuzzy theory, fuzzy subset and Membership Function
The fuzzy Analects of e, ec and u are [-6, 6], both with seven fuzzy sets NB (negative big), NM (negative middle), NS (negative small), ZO (zero), PS (positive small), PM (positive middle) and PB (positive big) to describe. e, ec and, Δu are all using triangular membership function (see Figure 2).
Figure 2. Input and output variable membership function
C. Fuzzy control rule table
The establishment principle of fuzzy control rules are: when the error is large, the output control volume should give priority to eliminate error as soon as possible; when the error is small, the output control volume should givepriority to prevent overshoot. Where ec is negative ,it shows that water level has a rising trend, if the water level is high at this time, then we should reduce the valve opening signal; whereas, we should open the valve more. Through a comprehensive analysis of expertise, the establishment of rule table shown in Table 1.
Table 1. Fuzzy control rule table
D. Fuzzy Reasoning and Solution
This fuzzy inference system uses Mamdani. The basic properties of fuzzy inference system set to: "and" operation with a very small operation; "or" operation uses the maximum operation. Using a very small operation fuzzy implication, fuzzy rules integrated with great operations center Defuzzification method used. IV . SIMULATION EXAMPLES
A pressurized water reactor steam generator in Chinese Qinshan nuclear power station has empirical model G1 (s), G2 (s) below:
()()()()
???????+?++++==---7%15,)
128(415.0)13)(129(19.36%90,)
13)(129(19.3)()(551Ps s s s s e Ps s s s e e s G s G s
s
s
p τ
()()
8%90,
1
4398
.0)124(819.3)(2Ps s s s s e s G +++--
=
where Ps denote the rated load. When load at 15% ~ 90% Ps, use (6) and (8); when load less than 15% Ps, use (7) and (8).
Figure 3. Expected water level step response diagram
The coefficients in Control system are k1=k2=0.5. Water control valve is a king of linear valve, its gain is 4. The quantitative coefficients of e and ec are 6 and 60 respectively; the scale factor of u is 0.5. We limit water flow the range of 0 kg / s to the rated flow 258kg / s when simulation. Consider the expected level step from the initial 0m to 10m, water level response is shown use the solid line in Figure 3. For contrasting the increase effect of fuzzy controller, we also carried out using the traditional PID control simulation. We can see, compared with traditional PID control, fuzzy controller has reported significant improvements in overshoot, settling time, steady degrees.
V. CONCLUSION
This paper designed a water level fuzzy control system aimed at steam ge nerator…s characteristics of large time delay and model uncertainty. We also gave a simulation to the steam generator of Qinshan nuclear power plant, and achieved satisfactory results. The method can also be used for other large time -delay and time-varying process control model, and has broad application prospects.
蒸汽发生器水位模糊控制研究
1.导论
蒸汽发生器是压水反应堆式核电厂里的一个重要的设备。为了保证核电厂运行的安全性，蒸汽发生器的水位必须控制在一定的范围内。核电厂的运行中，因为蒸汽流量和给水流量的改变，蒸汽发生器里沸水中的气泡数量会随着局部气压和温度的变化而改变，瞬时水位呈现“虚假液位”现象。正是由于“虚假液位”的存在使得水位控制变得困难。将前馈控制引入到传统的单回路PID控制中，可以在一定程度上克服“虚假液位”的问题。但是蒸汽发生器的传统PID控制仍然存在着一些不足。对于具有高度复杂，大滞后，非线性特征的蒸汽发生系统，不仅PID参数的调整单调乏味，控制效果也很差。并且当条件改变时，为了获得好的控制性能，通常需要改变PID控制器的参数，但是模拟量的PID控制器参数的在线调整是很难的。模糊控制是一种基于模糊推理的非线性的控制方法，它体现了熟练操作人员的实际经验和模糊语言推理的一般规则。模糊控制不需要知道被控对象的精确的数学模型，它对过程参数的变化并不敏感，鲁棒性很强，能够克服非线性因素，因此，模糊控制有更快的响应速度，更小的超调，更好的控制效果。基于以上了解，本文设计了一个蒸汽发生器水位的模糊控制器，仿真结果表明这个控制器有更好的控制效果和实用价值。
2.蒸汽发生器的动态特性
压水堆蒸汽发生器一般形式的数学模型的传递函数如下所示:
y(s)=GW(s)QW(s)+GS(s)QS(s)
（1）
其中，y代表蒸汽发生器的水位；QW代表给水流量；QS代表蒸汽流量；GW代表给水流量对蒸汽发生器水位的作用；GS代表蒸汽流量对蒸汽发生器的水位的作用。
蒸汽发生器水位的平衡是靠蒸汽流量和给水流量的匹配来维持的。可以将水位随蒸汽流量或者给水流量变化而变化看作一个简单的一体化过程，蒸汽流量变化和给水流量变化对水位的影响又是不同的。
(1)给水流量扰动下的动态特性
假设蒸汽流量保持不变，而给水流量阶跃增加，一方面，由于新增给水的温度要比蒸汽发生器中的饱和水的温度低很多，因此，当新水进入后就会吸收大量的额外热量，水中的气泡含量大大减少，从而导致水位下降；另一方面，给水流量大于蒸汽负荷，引起水位线性增加。综合以上两点，当给水阶跃增加，水位增长会有一个延迟的过程，表现为先下降后上升。
(2)蒸汽负荷扰动下的动态特性
假设给水流量保持不变，蒸汽负荷阶跃增加，一方面，由于蒸汽流速比给水流速大，水位会下降；另一方面，随着蒸汽负荷的增加，内部蒸汽压力降低，液面的气泡容积增加，从而引起水位增加。综合以上两个因素，当蒸汽流量阶跃增加以后，水位下降会有一个延迟的过程，表现为先上升后下降。
给水流量或者蒸汽流量阶跃减少对水位的影响与上述有相似的原理。
综上所述，当给水流量或者蒸汽负荷变化，水位不会立即跟随变化，开始会出现一个相反的过程。这个现象就称为“虚假液位”现象。
3.水位模糊控制器的设计
传统PID控制器对于蒸汽发生器水位的控制效果不佳，存在“虚假液位”的现象，表现为跟踪设定值时有较大的超调。但是，一个设计合理的模糊控制器能够克服“虚假液位”的现象，有较好的控制效果。
(1)模糊控制器的结构
模糊控制器的结构如图1所示。
图1 蒸汽发生器水位模糊控制器的结构
选择水位偏差（e）和偏差变化率（ec）作为模糊控制器的输入，模糊控制器的输出量为阀门开度的增量信号Δu。同时，以蒸汽流量作为前馈信号来克服“虚假液位”现象，以给水流量作为内反馈信号来克服给水波动。k1，k2是给水流量和蒸汽流量的传感器的转换系数。为了保证给水流量等于蒸汽流量， k1和k2应该相等。
(2)模糊理论、模糊子集和隶属函数
e、ec 和 u 的模糊论域是[-6, 6]，用NB（负大）、NM（负中）、NS（负小）、ZO（零）、PS（正小）、PM（正中）和PB（正大）7个模糊子集描述。e，ec 和Δu 都采用三角形隶属函数（如图2）。
图2 输入输出隶属函数
(3)模糊控制规则列表
模糊控制规则建立的原则是：当偏差大，输出控制量应该优先以尽快消除偏差为主；当偏差小，输出控制量应优先消除超调。当偏差变化率为负，这表明水位有上升的趋势，如果此时水位高，应减小阀门开度；相反，应就应当开大阀门。通过专业的分析，建立如表1所示的规则表。
表1 模糊控制规则表
(4)模糊推理和模糊判决
本次设计的模糊推理系统采用Mamdani型。模糊推理系统的基本属性设置为：“与”算法为取小算法；“或”算法为取大算法。模糊蕴含采用取小算法；模糊综合采用取大算法；清晰化采用重心法。
4.仿真实例
中国秦山核电站的一个压水堆蒸汽发生器有如下的实验模型：
()()()()
???
????+?++++==---7%15,)128(415.0)13)(129(19.36%90,)
13)(129(19.3)()(551Ps s s s s e Ps s s s e e
s G s G s
s
s
p τ
()()
8%90,
1
4398
.0)124(819.3)(2Ps s s s s e s G +++--
=
其中，Ps 表示额定的负荷。当负荷为15% ~ 90% Ps 时，用公式(6) 和(8)，当负荷小于15% Ps 时，用公式(7)和(8)。
图3 预期水位阶跃响应图
控制系统的系数k1=k2=0.5。给水控制阀是一个线性阀，增益为4。e 和ec 的量化因子分别为6和60，u 的比例因子为0.5。仿真时，我们限定给水流量的范围在0kg/s 到额定流量258kg/s 。假设预期水位从0m 上升到10m ，水位响应如图3中的实线所示。为了比较模糊控制器增加的效果，我们也作出传统PID 控制的仿真结果。可以看出，与传统PID 控制相比，模糊控制在超调量、调节时间和稳态特性方面有重要的改善。 5.结论
本论文针对蒸汽产生器大延迟和模型不确定的特性，设计了一个水位模糊控制系统。我们还给出了秦山核电站的蒸汽发生器的仿真，并获得了令人满意的效果。这种方法同样适用于其它的大滞后和非线性系统的控制模型，具有广阔的应用前景。
A Clear Look at Internal Controls: Theory and Concepts Hammed Arad (Philae) Department of accounting, Islamic Azad University, Hamadan, Iran Barak Jamshedy-Navid Faculty Member of Islamic Azad University, Kerman-shah, Iran Abstract: internal control is an accounting procedure or system designed to promote efficiency or assure the implementation of a policy or safeguard assets or avoid fraud and error. Internal Control is a major part of managing an organization. It comprises the plans, methods, and procedures used to meet missions, goals, and objectives and, in doing so, support performance-based management. Internal Control which is equal with management control helps managers achieve desired results through effective stewardship of resources. Internal controls should reduce the risks associated with undetected errors or irregularities, but designing and establishing effective internal controls is not a simple task and cannot be accomplished through a short set of quick fixes. In this paper the concepts of internal controls and different aspects of internal controls are discussed. Keywords: Internal Control, management controls, Control Environment, Control Activities, Monitoring 1. Introduction The necessity of control in new variable business environment is not latent for any person and management as a response factor for stockholders and another should implement a great control over his/her organization. Control is the activity of managing or exerting control over something. he emergence and development of systematic thoughts in recent decade required a new attention to business resource and control over this wealth. One of the hot topic a bout controls over business resource is analyzing the cost-benefit of each control. Internal Controls serve as the first line of defense in safeguarding assets and preventing and detecting errors and fraud. We can say Internal control is a whole system of controls financial and otherwise, established by the management for the smooth running of business; it includes internal cheek, internal audit and other forms of controls. COSO describe Internal Control as follow. Internal controls are the methods employed to help ensure the achievement of an objective. In accounting and organizational theory, Internal control is defined as a process effected by an organization's structure, work and authority flows, people and management information systems, designed to help the organization accomplish specific goals or objectives. It is a means by which an organization's resources are directed, monitored, and measured. It plays an important role in preventing and detecting fraud and protecting the organization's resources, both physical (e.g., machinery and property) and intangible (e.g., reputation or intellectual property such as trademarks). At the organizational level, internal control objectives relate to the reliability of financial reporting, timely feedback on the achievement of operational or strategic goals, and compliance with laws and regulations. At the specific transaction level, internal control refers to the actions taken to achieve a specific objective (e.g., how to ensure the organization's payments to third parties are for valid services rendered.) Internal control
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.
控制系统基础论文中英文资料外文翻译文献 文献翻译 原文： Numerical Control One of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC).Prior to the advent of NC, all machine tools were manual operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator . Numerical control represents the first major step away from human control of machine tools. Numerical control means the control of machine tools and other manufacturing systems though the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool, For a machine tool to be numerically controlled , it must be interfaced with a device for accepting and decoding the p2ogrammed instructions, known as a reader. Numerical control was developed to overcome the limitation of human operator , and it has done so . Numerical control machines are more accurate than manually operated machines , they can produce parts more uniformly , they are faster, and the long-run tooling costs are lower . The development of NC led to the development of several other innovations in manufacturing technology: 1.Electrical discharge machining. https://www.doczj.com/doc/7812876369.html,ser cutting. 3.Electron beam welding.
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。
会计内部控制中英文对照外文翻译文献(文档含英文原文和中文翻译)
内部控制透视：理论与概念 摘要：内部控制是会计程序或控制系统，旨在促进效率或保证一个执行政策或保护资产或避免欺诈和错误。内部是一个组织管理的重要组成部分。它包括计划、方法和程序使用，以满足任务，目标和目的，并在这样做，支持基于业绩的管理。内部控制是管理阶层的平等与控制可以帮助管理者实现资源的预期的有效管理的结果通过。内部控制应减少或违规错误的风险关联未被发现的，但设计和建立有效的内部控制不是一个简单的任务，不可能是一个实现通过快速修复短套。在此讨论了内部文件的概念的不同方面的内部控制和管制。 关键词：内部控制，管理控制，控制环境，控制活动，监督 1、介绍 环境需要新的业务控制变量不为任何潜在的股东和管理人士的响应因子为1，另外应执行/她组织了一个很大的控制权。控制是管理活动的东西或以上施加控制。思想的产生和近十年的发展需要有系统的商业资源和控制这种财富一个新的关注。主题之一热一回合管制的商业资源是分析每个控制成本效益。 作为内部控制和欺诈的第一道防线，维护资产以及预防和侦查错误。内部控制，我们可以说是一种控制整个系统的财务和其他方面的管理制定了为企业的顺利运行;它包括内部的脸颊，内部审计和其他形式的控制。 COSO的内部控制描述如下。内部控制是一个客观的方法用来帮助确保实现。在会计和组织理论，内部控制是指或目标目标的过程实施由组织的结构，工作和权力流动，人员和具体的管理信息系统，旨在帮助组织实现。这是一种手段，其中一个组织的资源被定向，监控和测量。它发挥着无形的（重要的作用，预防和侦查欺诈和保护组织的资源，包括生理（如，机械和财产）和乙二醇，声誉或知识产权，如商标）。在组织水平，内部控制目标与可靠性的目标或战略的财务报告，及时反馈业务上的成就，并遵守法律，法规。在具体的交易水平，内部控制是指第三方采取行动以实现一个具体目标（例如，如何确保本组织的款项，在申请服务提供有效的。）内部控制程序reduce程变异，导
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。
毕业设计(论文)外文资料翻译 学院：机械工程学院 专业：机械设计制造及其自动化 姓名： 学号：XXXXXXXXXX 外文出处：《Computational Intelligence and (用外文写)Design》 附件： 1.外文资料翻译译文；2.外文原文。 注：请将该封面与附件装订成册。
附件1：外文资料翻译译文 基于微型计算机的步进电机控制系统设计 孟天星余兰兰 山东理工大学电子与电气工程学院 山东省淄博市 摘要 本文详细地介绍了一种以AT89C51为核心的步进电机控制系统。该系统设计包括硬件设计、软件设计和电路设计。电路设计模块包括键盘输入模块、LED显示模块、发光二极管状态显示和报警模块。按键可以输入设定步进电机的启停、转速、转向,改变转速、转向等的状态参数。通过键盘输入的状态参数来控制步进电机的步进位置和步进速度进而驱动负载执行预订的工作。运用显示电路来显示步进电机的输入数据和运行状态。AT89C51单片机通过指令系统和编译程序来执行软件部分。通过反馈检测模块，该系统可以很好地完成上述功能。 关键词：步进电机，AT89C51单片机，驱动器，速度控制 1概述 步进电机因为具有较高的精度而被广泛地应用于运动控制系统，例如机器人、打印机、软盘驱动机、绘图仪、机械式阀体等等。过去传统的步进电机控制电路和驱动电路设计方法通常都极为复杂，由成本很高而且实用性很差的电器元件组成。结合微型计算机技术和软件编程技术的设计方法成功地避免了设计大量复杂的电路，降低了使用元件的成本，使步进电机的应用更广泛更灵活。本文步进电机控制系统是基于AT89C51单片机进行设计的，它具有电路简单、结构紧凑的特点，能进行加减速，转向和角度控制。它仅仅需要修改控制程序就可以对各种不同型号的步进电机进行控制而不需要改变硬件电路，所以它具有很广泛的应用领域。 2设计方案 该系统以AT89C51单片机为核心来控制步进电机。电路设计包括键盘输入电路、LED显示电路、发光二极管显示电路和报警电路，系统原理框图如图1所示。 At89c51单片机的P2口输出控制步进电机速度的时钟脉冲信号和控制步进电机运转方向的高低电平。通过定时程序和延时程序可以控制步进电机的速度和在某一
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
本科毕业论文（设计）文献综述和外文翻译 撰写要求与格式规范 一、毕业论文（设计）文献综述 （一）毕业论文（设计）文献综述的内容要求 1．封面：由学院统一设计，普通A4纸打印即可。 2.正文 综述正文部分需要阐述所选课题在相应学科领域中的发展进程和研究方向，特别是近年来的发展趋势和最新成果。通过与中外研究成果的比较和评论，说明自己的选题是符合当前的研究方向并有所进展，或采用了当前的最新技术并有所改进，目的是使读者进一步了解本课题的意义。文中的用语、图纸、表格、插图应规范、准确，量和单位的使用必须符合国家标准规定，引用他人资料要有标注。 文献综述字数在5000字以上。 正文前须附500字左右中文摘要，末尾须附参考文献。 参考文献的著录按在文献综述中出现的先后顺序编号。 期刊类文献书写方法:[序号]作者（不超过3人，多者用等表示）.题（篇）名[J].刊名,出版年,卷次（期次）:起止页次.
图书类文献书写方法:[序号]作者.书名[M].版本.出版地:出版者,出版年:起止页次. 论文集类文献书写方法:[序号]作者.篇名[C].论文集名.出版地:出版者,出版年:起止页次. 学位论文类书写方法:[序号]作者.篇名[D].出版地:单位名称,年份. 电子文献类书写方法:[序号]主要责任者. 题名:其他题名信息[文献类型标志/文献载体标志 ]出版地:出版者,出版年（更新或修改日期）[引用日期].获取和访问途径. 参考文献篇数应符合学院毕业论文（设计）工作的要求。 （二）毕业论文（设计）文献综述撰写与装订的格式规范 第一部分：封面 1.封面：由学院统一设计，“本科生毕业论文（设计）”根据作业实际明确为“论文”或“设计”，其它文本、表格遇此类情况同样处理。 第二部分：文献综述主题 1.中文摘要与关键词 摘要标题（五号，宋体，顶格，加粗）
外文出处：Maijoor S. The Internal Control Explosion[J]. International Journal of Auditing, 2000, 4(1):101–109. 内部控制爆炸① 摘要：Power的1997版书以审计社会为主题的探讨使得审计活动在联合王国（英国）和北美得到扩散。由审计爆炸一同带动的是内部控制制度的兴起。审计已经从审计结果转向审计制度和内部控制，它已内部控制爆炸然成为公众对公司治理和审计监管政策的辩论主题。Power表示对什么是有效的内部控制各方说法不一。本人对内部控制研究方面有一个合理的解释。内部控制对非常不同概念的各个领域的会计进行探究，并研究如何控制不同水平的组织。因此，内部控制研究的各类之间的交叉影响是有限的，而且，许多内部会计控制是研究是再更宽广的公司治理问题的背景下进行的。所以，许多有关内部控制制度对公司治理的价值观点扔需要进行研究。 关键词：机构理论；公司治理；外部审计；内部审计；内部控制制度；管理控制 1 概述 Power的1997版书以审计社会为主题的探讨使得审计活动在联合王国（英国）和北美得到扩散。由审计爆炸一同带动的是内部控制制度的兴起。审计已经从审计结果转向审计制度和内部控制，它已然成为公众对公司治理和审计监管政策的辩论主题。例如，在最近的对于欧洲联盟内外部审计服务的内部市场形成的辩论中，监管建议建立关于内部控制和内部审计制度。虽然对有关内部控制的价值期望高，但Power表示对什么是有效的内部控制各方说法不一。本人对内部控制研究方面有一个合理的解释。内部控制是对非常不同概念的各个领域的会计进行探究，并研究如何控制不同水平的组织。因此，内部控制研究的各类之间的交叉影响是有限的，而且，许多内部会计控制是研究是再更宽广的公司治理问题的背景下进行的。所以，许多有关内部控制制度对公司治理的价值观点扔需要进行研究。 在审计和公司治理的公共政策辩论中，内部控制的概念越来越得到重视。公共越来①Maastricht Accounting and Auditing Research and Education Center (MARC), Faculty of Economics and Business Administration, Universiteit Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands s.maijoor@marc.unimaas.nl Fax: 31-43-3884876 Tel: 31-43-3883783
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。