中英文资料外文翻译文献
EXTENDING BEARING LIFE
Abstract：
Nature works hard to destroy bearings, but their chances of survival can be improved by following a few simple guidelines. Extreme neglect in a bearing leads to overheating and possibly seizure or, at worst, an explosion. But even a failed bearing leaves clues as to what went wrong. After a little detective work, action can be taken to avoid a repeat performance.
Keywords: bearings failures life
Bearings fail for a number of reasons，but the most common are misapplication，contamination，improper lubricant，shipping or handling damage，and misalignment. The problem is often not difficult to diagnose because a failed bearing usually leaves telltale signs about what went wrong．
However，while a postmortem yields good information，it is better to avoid the process altogether by specifying the bearing correctly in The first place．To do this，it is useful to review the manufacturers sizing guidelines and operating characteristics for the selected bearing.
Equally critical is a study of requirements for noise, torque, and runout, as well as possible exposure to contaminants, hostile liquids, and temperature extremes. This can provide further clues as to whether a bearing is right for a job.
1 Why bearings fail
About 40% of ball bearing failures are caused by contamination from dust, dirt, shavings, and corrosion. Contamination also causes torque and noise problems, and is often the result of improper handling or the application environment．Fortunately, a bearing failure caused by environment or handling contamination is preventable，and a simple visual examination can easily identify the cause．
Conducting a postmortem il1ustrates what to look for on a failed or failing bearing．Then，understanding the mechanism behind the failure, such as brinelling or fatigue, helps eliminate the source of the problem.
Brinelling is one type of bearing failure easily avoided by proper handing and
assembly. It is characterized by indentations in the bearing raceway caused by shock loading－such as when a bearing is dropped-or incorrect assembly. Brinelling usually occurs when loads exceed the material yield point(350,000 psi in SAE 52100 chrome steel)．It may also be caused by improper assembly, Which places a load across the races．Raceway dents also produce noise，vibration，and increased torque.
A similar defect is a pattern of elliptical dents caused by balls vibrating between raceways while the bearing is not turning．This problem is called false brinelling. It occurs on equipment in transit or that vibrates when not in operation. In addition, debris created by false brinelling acts like an abrasive, further contaminating the bearing. Unlike brinelling, false binelling is often indicated by a reddish color from fretting corrosion in the lubricant.
False brinelling is prevented by eliminating vibration sources and keeping the bearing well lubricated. Isolation pads on the equipment or a separate foundation may be required to reduce environmental vibration. Also a light preload on the bearing helps keep the balls and raceway in tight contact. Preloading also helps prevent false brinelling during transit.
Seizures can be caused by a lack of internal clearance, improper lubrication, or excessive loading. Before seizing, excessive, friction and heat softens the bearing steel. Overheated bearings often change color，usually to blue-black or straw colored．Friction also causes stress in the retainer，which can break and hasten bearing failure．Premature material fatigue is caused by a high load or excessive preload．When these conditions are unavoidable，bearing life should be carefully calculated so that a maintenance scheme can be worked out．
Another solution for fighting premature fatigue is changing material．When standard bearing materials，such as 440C or SAE 52100，do not guarantee sufficient life，specialty materials can be recommended. In addition，when the problem is traced back to excessive loading，a higher capacity bearing or different configuration may be used．Creep is less common than premature fatigue．In bearings．it is caused by excessive clearance between bore and shaft that allows the bore to rotate on the shaft．Creep can be expensive because it causes damage to other components in addition to the bearing．0ther more likely creep indicators are scratches，scuff marks，or discoloration to shaft and bore．To prevent creep damage，the bearing housing and shaft fittings should be visually checked．
Misalignment is related to creep in that it is mounting related．If races are misaligned or cocked．The balls track in a noncircumferencial path．The problem is incorrect mounting or tolerancing，or insufficient squareness of the bearing mounting site．Misalignment of more than 1/4·can cause an early failure．
Contaminated lubricant is often more difficult to detect than misalignment or creep．Contamination shows as premature wear．Solid contaminants become an abrasive in the lubricant．In addition。insufficient lubrication between ball and retainer wears and weakens the retainer．In this situation，lubrication is critical if the retainer is a fully machined type．Ribbon or crown retainers，in contrast，allow lubricants to more easily reach all surfaces．
Rust is a form of moisture contamination and often indicates the wrong material for the application．If the material checks out for the job，the easiest way to prevent rust is to keep bearings in their packaging，until just before installation．
2 Avoiding failures
The best way to handle bearing failures is to avoid them．This can be done in the selection process by recognizing critical performance characteristics．These include noise，starting and running torque，stiffness，nonrepetitive runout，and radial and axial play．In some applications, these items are so critical that specifying an ABEC level alone is not sufficient．
Torque requirements are determined by the lubricant，retainer，raceway quality(roundness cross curvature and surface finish)，and whether seals or shields are used．Lubricant viscosity must be selected carefully because inappropriate lubricant，especially in miniature bearings，causes excessive torque．Also，different lubricants have varying noise characteristics that should be matched to the application. For example，greases produce more noise than oil．
Nonrepetitive runout(NRR)occurs during rotation as a random eccentricity between the inner and outer races，much like a cam action．NRR can be caused by retainer tolerance or eccentricities of the raceways and balls．Unlike repetitive runout, no compensation can be made for NRR.
NRR is reflected in the cost of the bearing．It is common in the industry to provide different bearing types and grades for specific applications．For example，a bearing with an NRR of less than 0.3um is used when minimal runout is needed，such as in disk—drive spindle motors．Similarly，machine—tool spindles tolerate only minimal deflections to maintain precision cuts．Consequently, bearings are manufactured with low NRR just for machine-tool applications．
Contamination is unavoidable in many industrial products，and shields and seals are commonly used to protect bearings from dust and dirt．However，a perfect bearing seal is not possible because of the movement between inner and outer races．Consequently，lubrication migration and contamination are always problems．
Once a bearing is contaminated, its lubricant deteriorates and operation becomes
noisier．If it overheats，the bearing can seize．At the very least，contamination causes wear as it works between balls and the raceway，becoming imbedded in the races and acting as an abrasive between metal surfaces．Fending off dirt with seals and shields illustrates some methods for controlling contamination．
Noise is as an indicator of bearing quality．Various noise grades have been developed to classify bearing performance capabilities．
Noise analysis is done with an Anderonmeter, which is used for quality control in bearing production and also when failed bearings are returned for analysis. A transducer is attached to the outer ring and the inner race is turned at 1,800rpm on an air spindle. Noise is measured in andirons, which represent ball displacement in μm/rad.
With experience, inspectors can identify the smallest flaw from their sound. Dust, for example, makes an irregular crackling. Ball scratches make a consistent popping and are the most difficult to identify. Inner-race damage is normally a constant high-pitched noise, while a damaged outer race makes an intermittent sound as it rotates.
Bearing defects are further identified by their frequencies. Generally, defects are separated into low, medium, and high wavelengths. Defects are also referenced to the number of irregularities per revolution.
Low-band noise is the effect of long-wavelength irregularities that occur about 1.6 to 10 times per revolution. These are caused by a variety of inconsistencies, such as pockets in the race. Detectable pockets are manufacturing flaws and result when the race is mounted too tightly in multiplejaw chucks.
Medium-hand noise is characterized by irregularities that occur 10 to 60 times per revolution. It is caused by vibration in the grinding operation that produces balls and raceways. High-hand irregularities occur at 60 to 300 times per revolution and indicate closely spaced chatter marks or widely spaced, rough irregularities.
Classifying bearings by their noise characteristics allows users to specify a noise grade in addition to the ABEC standards used by most manufacturers. ABEC defines physical tolerances such as bore, outer diameter, and runout. As the ABEC class number increase (from 3 to 9), tolerances are tightened. ABEC class, however, does not specify other bearing characteristics such as raceway quality, finish, or noise. Hence, a noise classification helps improve on the industry standard.
GEAR AND SHAFT INTRODUCTION
Abstract:
The important position of the wheel gear and shaft can't falter in traditional machine and modern machines. The wheel gear and shafts mainly install the direction that delivers
the dint at the principal axis box. The passing to process to make them can is divided into many model numbers, useding for many situations respectively. So we must be the multilayers to the understanding of the wheel gear and shaft in many ways .
Key words:Wheel gear Shaft
In the force analysis of spur gears, the forces are assumed to act in a single plane. We shall study gears in which the forces have three dimensions. The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. And in the case of bevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn.
Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid.
The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement. In spur gears the line of contact is parallel to the axis of the rotation; in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side by side on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft, the hand of the gears should be selected so as to produce the minimum thrust load.
Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power. There is on difference between a crossed helical gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand; that is ,a right-hand driver goes with a right-hand driven. In the design
of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle are equal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand.
Worm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm gear are used to provide a high angular-velocity reduction between nonintersecting shafts which are usually at right angle. The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact. However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed helical gears.
Worm gearing are either single or double enveloping. A single-enveloping gearing is one in which the gear wraps around or partially encloses the worm.. A gearing in which each element partially encloses the other is, of course, a double-enveloping worm gearing. The important difference between the two is that area contact exists between the teeth of double-enveloping gears while only line contact between those of single-enveloping gears. The worm and worm gear of a set have the same hand of helix as for crossed helical gears, but the helix angles are usually quite different. The helix angle on the worm is generally quite large, and that on the gear very small. Because of this, it is usual to specify the lead angle on the worm, which is the complement of the worm helix angle, and the helix angle on the gear; the two angles are equal for a 90-deg. Shaft angle.
When gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required. Although bevel gear are usually made for a shaft angle of 90 deg. They may be produced for almost any shaft angle. The teeth may be cast, milled, or generated. Only the generated teeth may be classed as accurate. In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing. This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth. Another difficulty, which occurs in predicting the stress in bevel-gear teeth, is the fact the teeth are tapered.
Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively. As in the case of squr gears, however, they become noisy at higher values of the pitch-line velocity. In these cases it is often good design practice to go to the spiral bevel gear, which is the bevel counterpart of the helical gear. As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered.
It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset. Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution. The tooth action between such gears is a combination of rolling and sliding along a straight line and has much in common with that of worm gears.
A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other power-transmission elements. Shaft may be subjected to bending, tension, compression, or torsional loads, acting singly or in combination with one another. When they are combined, one may expect to find both static and fatigue strength to be important design considerations, since a single shaft may be subjected to static stresses, completely reversed, and repeated stresses, all acting at the same time.
The word “shaft” covers numerous variations, such as axles and spindles. Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load. A shirt rotating shaft is often called a spindle.
When either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of deflection before analyzing the stresses. The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe. But by no means should the designer assume that they are safe; it is almost always necessary to calculate them so that he knows they are within acceptable limits. Whenever possible, the power-transmission elements, such as gears or pullets, should be located close to the supporting bearings, This reduces the bending moment, and hence the deflection and bending stress.
Although the von Mises-Hencky-Goodman method is difficult to use in design of shaft, it probably comes closest to predicting actual failure. Thus it is a good way of checking a shaft that has already been designed or of discovering why a particular shaft has failed in service. Furthermore, there are a considerable number of shaft-design problems in which the dimension are pretty well limited by other considerations, such as rigidity, and it is only necessary for the designer to discover something about the fillet sizes, heat-treatment, and surface finish and whether or not shot peening is necessary in order to achieve the required life and reliability.
Because of the similarity of their functions, clutches and brakes are treated together. In a simplified dynamic representation of a friction clutch, or brake, two inertias I1 and I2 traveling at the respective angular velocities W1 and W2, one of which may be zero in the case of brake, are to be brought to the same speed by engaging the clutch or brake. Slippage occurs because the two elements are running at different speeds and energy is
dissipated during actuation, resulting in a temperature rise. In analyzing the performance of these devices we shall be interested in the actuating force, the torque transmitted, the energy loss and the temperature rise. The torque transmitted is related to the actuating force, the coefficient of friction, and the geometry of the clutch or brake. This is problem in static, which will have to be studied separately for eath geometric configuration. However, temperature rise is related to energy loss and can be studied without regard to the type of brake or clutch because the geometry of interest is the heat-dissipating surfaces. The various types of clutches and brakes may be classified as follows:
1.Rim type with internally expanding shoes
2.Rim type with externally contracting shoes
3.Band type
4.Disk or axial type
5.Cone type
6.Miscellaneous type
The analysis of all type of friction clutches and brakes use the same general procedure. The following step are necessary:
1.Assume or determine the distribution of pressure on the frictional surfaces.
2.Find a relation between the maximum pressure and the pressure at any point
3.Apply the condition of statical equilibrium to find (a) the actuating force, (b)
the torque, and (c) the support reactions.
Miscellaneous clutches include several types, such as the positive-contact clutches, overload-release clutches, overrunning clutches, magnetic fluid clutches, and others.
A positive-contact clutch consists of a shift lever and two jaws. The greatest differences between the various types of positive clutches are concerned with the design of the jaws. To provide a longer period of time for shift action during engagement, the jaws may be ratchet-shaped, or gear-tooth-shaped. Sometimes a great many teeth or jaws are used, and they may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of the mating elements.
Although positive clutches are not used to the extent of the frictional-contact type, they do have important applications where synchronous operation is required.
Devices such as linear drives or motor-operated screw drivers must run to definite limit and then come to a stop. An overload-release type of clutch is required for these applications. These clutches are usually spring-loaded so as to release at a predetermined toque. The clicking sound which is heard when the overload point is reached is considered to be a desirable signal.
An overrunning clutch or coupling permits the driven member of a machine to
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.
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。
例： 参考文献： [1]毛蕴诗. 跨国公司战略竞争与国际直接投资[M].广州: 中山大学出版社 [2]ALEXANDER N. International Retailing [M].Oxford:Blackwell Business,1997 .日本税法[M].战宪斌,郑林根,译.北京:法律出版社.信息技术与信息服务[M]//许厚泽,赵其国.信息技术与应用.,於方,蒋红强,等. 建立中国绿色GDP 核算体系:机遇、挑战与对策[C]//潘岳,绿色GDP 核算体系国际研讨会论文集. 北京:中国环境科学出版社, 2004:35-42. 黄祖洽.软凝聚态物理研究进展[J].北京师范大学学报:自然科学版,2005,41(1) :N, MYERS H. European Retail Expansion in South East Asia[J].European 1999,34(2): 45-50. 丁文祥.数字革命与竞争国际化[N]. 中国青年报, 2000-11-20 (15). 张志祥.间断动力系统的随机扰动及其在守恒律方程中的应用[D].北京:北京大学数学学院,1998. 冯西桥.核反应堆压力管 道与压力容器的LBB 分析[R].北京:清华大学核能技术设计研究院莫少强.数字式中文全文文献格式的设计与研究[J/OL].情报学报,1999,18(4):https://www.doczj.com/doc/af16247974.html,/periodical/qbxb/qbxb990407.htm. 奚纪荣,邱志方.武略文韬:军事知识趣谈[M/OL].上海: 汉语大词典出版社, 2001: [13]杜莲.“9·11”事件影响英国出版news/20010929/200109290016.htm. 英文作者姓名全部 用大写字母
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。
英语专业毕业论文翻译 类论文 Document number：NOCG-YUNOO-BUYTT-UU986-1986UT
毕业论文（设计）Title:The Application of the Iconicity to the Translation of Chinese Poetry 题目:象似性在中国诗歌翻译中的应用 学生姓名孔令霞 学号 BC09150201 指导教师祁晓菲助教 年级 2009级英语本科（翻译方向）二班 专业英语 系别外国语言文学系
黑龙江外国语学院本科生毕业论文（设计）任务书 摘要
索绪尔提出的语言符号任意性，近些年不断受到质疑，来自语言象似性的研究是最大的挑战。语言象似性理论是针对语言任意性理论提出来的，并在不断发展。象似性是当今认知语言学研究中的一个重要课题，是指语言符号的能指与所指之间的自然联系。本文以中国诗歌英译为例，探讨象似性在中国诗歌翻译中的应用，从以下几个部分阐述：（1）象似性的发展；（2）象似性的定义及分类；（3）中国诗歌翻译的标准；（4）象似性在中国诗歌翻译中的应用，主要从以下几个方面论述：声音象似、顺序象似、数量象似、对称象似方面。通过以上几个方面的探究，探讨了中国诗歌翻译中象似性原则的重大作用，在诗歌翻译过程中有助于得到“形神皆似”和“意美、音美、形美”的理想翻译效果。 关键词：象似性；诗歌；翻译
Abstract The arbitrariness theory of language signs proposed by Saussure is severely challenged by the study of language iconicity in recent years. The theory of iconicity is put forward in contrast to that of arbitrariness and has been developing gradually. Iconicity, which is an important subject in the research of cognitive linguistics, refers to a natural resemblance or analogy between the form of a sign and the object or concept. This thesis mainly discusses the application of the iconicity to the translation of Chinese poetry. The paper is better described from the following parts: (1) The development of the iconicity; (2) The definition and classification of the iconicity; (3) The standards of the translation to Chinese poetry; (4) The application of the iconicity to the translation of Chinese poetry, mainly discussed from the following aspects: sound iconicity, order iconicity, quantity iconicity, and symmetrical iconicity. Through in-depth discussion of the above aspects, this paper could come to the conclusion that the iconicity is very important in the translation of poetry. It is conductive to reach the ideal effect of “the similarity of form and spirit” and “the three beauties”. Key words: the iconicity; poetry; translation
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）
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。
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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
本科毕业设计（论文）外文翻译基本规范 一、要求 1、与毕业论文分开单独成文。 2、两篇文献。 二、基本格式 1、文献应以英、美等国家公开发表的文献为主（Journals from English speaking countries）。 2、毕业论文翻译是相对独立的，其中应该包括题目、作者（可以不翻译）、译文的出处（杂志的名称）（5号宋体、写在文稿左上角）、关键词、摘要、前言、正文、总结等几个部分。 3、文献翻译的字体、字号、序号等应与毕业论文格式要求完全一致。 4、文中所有的图表、致谢及参考文献均可以略去，但在文献翻译的末页标注：图表、致谢及参考文献已略去(见原文)。（空一行，字体同正文） 5、原文中出现的专用名词及人名、地名、参考文献可不翻译，并同原文一样在正文中标明出处。 二、毕业论文（设计）外文翻译 （一）毕业论文（设计）外文翻译的内容要求 外文翻译内容必须与所选课题相关，外文原文不少于6000个印刷符号。译文末尾要用外文注明外文原文出处。 原文出处：期刊类文献书写方法：[序号]作者（不超过3人，多者用等或et al表示）.题（篇）名[J].刊名（版本）,出版年，卷次（期次）：起止页次. 原文出处：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. 原文出处：论文集类文献书写方法：[序号]作者.篇名[A].编著者.论文集名[C]. 出版地：出版者，出版年.起止页次。 要求有外文原文复印件。 （二）毕业论文（设计）外文翻译的撰写与装订的格式规范 第一部分：封面
1.封面格式:见“毕业论文（设计）外文翻译封面”。普通A4纸打印即可。 第二部分：外文翻译主题 1.标题 一级标题，三号字，宋体，顶格，加粗 二级标题，四号字，宋体，顶格，加粗 三级标题，小四号字，宋体，顶格，加粗 2.正文 小四号字，宋体。 第三部分：版面要求 论文开本大小：210mm×297mm（A4纸） 版芯要求：左边距：25mm，右边距：25mm，上边距：30mm，下边距：25mm，页眉边距：23mm，页脚边 距：18mm 字符间距：标准 行距：1.25倍 页眉页角：页眉的奇数页书写—浙江师范大学学士学位论文外文翻译。页眉的偶数页书写—外文翻译 题目。在每页底部居中加页码。（宋体、五号、居中） 装订顺序是：封皮、中文翻译、英文原文复印件。
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/af16247974.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/af16247974.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