正电原子在电离过程中碰撞的理论外文文献翻译、中英文翻译、外文翻译

实验方法辐射黑色体理论（Chao et al., 1961）和切削表面理论（Friedman and Lenz, 1970）。

随着敏感的红外感光胶片的发展，在一个可被记录切削侧面温度场的工具（Boothroyd, 1961）和电视型红外线敏感的视频设备已被哈里斯等人使用（1980年），以热传感和半导体量子吸收的原则为基础的红外线传感器的不断发展，使得这些传感器的第二敏感性大于第一次，其时间常数很小太- 在微秒到毫秒的范围之内。

图5.21显示了最新使用的第二类的例子。

有两个传感器以及开始投入使用，一个是在1毫米至5毫米的波长范围的敏感型锑化铟，另外一个是从6毫米至13毫米的敏感型碲镉汞类型，通过与两个不同的探测器信号比较可以使用温度测量更敏感的方法。

大部分金属切削温度已进行了调查和了解使得更好地了解这个过程。

原则上，温度测量可能用于条件监测，例如，警告说如果是天气太热导致切割刀具后刀面磨损，然而，尤其是辐射能尺寸，在生产条件，校准问题以及确保辐射能量途径从伤口区到探测器不被打断的困难，使得以温度测量为目的方法不够可靠切削的另一种方式是监测声发射，这虽然是一个间接的方法，但研究过程的状态是一个值得考虑未来。

5.4 声发射材料的活跃形变—例如裂缝的增长，变形夹杂物，快速塑性剪切，甚至晶界，位错运动都是伴随着弹性应力波的排放而产生。

这就是声发射（AE）。

排放的发生在一个很宽的频率范围内，但通常是从10万赫到1兆赫。

虽然波幅度很小，但是他们可以被检测到，通过强烈的压电材料如钛酸钡或压电陶瓷传感器制造从，（Pb（Zr x Ti1–x）O3; x = 0.5 to 0.6）。

图5.22显示了传感器的结构。

声波传送到压力传感器造成直接的压力E（△L/L），其中E是传感器的杨氏模量，L 是它的长度，△L是它的长度变化。

应力产生电场T = g33E(△L/L)（5.7a）g33是传感器材料的压电应力系数。

传感器两端的电压是TL，然后V= g33E△L（5.7b）g33和E的典型值分别是24.4 × 10-3Vm/ N和58.5GPa，以检测电压高达0.01毫伏，这是可能的。

外文文献翻译(含：英文原文及中文译文)英文原文POSSIBILITIES AND LIMITA TIONS OF ACCIDENT ANALYSISS.OppeAbstraetAccident statistics, especially collected at a national level are particularly useful for the description, monitoring and prognosis of accident developments, the detection of positive and negative safety developments, the definition of safety targets and the (product) evaluation of long term and large scale safety measures. The application of accident analysis is strongly limited for problem analysis, prospective and retrospective safety analysis on newly developed traffic systems or safety measures, as well as for (process) evaluation of special short term and small scale safety measures. There is an urgent need for the analysis of accidents in real time, in combination with background behavioural research. Automatic incident detection, combined with video recording of accidents may soon result in financially acceptable research. This type of research may eventually lead to a better understanding of the concept of risk in traffic and to well-established theories.Keyword: Consequences; purposes; describe; Limitations; concerned; Accident Analysis; possibilities1. Introduction.This paper is primarily based on personal experience concerning traffic safety, safety research and the role of accidents analysis in this research. These experiences resulted in rather philosophical opinions as well as more practical viewpoints on research methodology and statistical analysis. A number of these findings are published already elsewhere.From this lack of direct observation of accidents, a number of methodological problems arise, leading to continuous discussions about the interpretation of findings that cannot be tested directly. For a fruitful discussion of these methodological problems it is very informative to look at a real accident on video. It then turns out that most of the relevant information used to explain the accident will be missing in the accident record. In-depth studies also cannot recollect all the data that is necessary in order to test hypotheses about the occurrence of the accident. For a particular car-car accident, that was recorded on video at an urban intersection in the Netherlands, between a car coming from a minor road, colliding with a car on the major road, the following questions could be asked: Why did the driver of the car coming from the minor road, suddenly accelerate after coming almost to a stop and hit the side of the car from the left at the main road? Why was the approaching car not noticed? Was it because the driver was preoccupied with the two cars coming from the right and the gap before them that offered him thepossibility to cross? Did he look left before, but was his view possibly blocked by the green van parked at the corner? Certainly the traffic situation was not complicated. At the moment of the accident there were no bicyclists or pedestrians present to distract his attention at the regularly overcrowded intersection. The parked green van disappeared within five minutes, the two other cars that may have been important left without a trace. It is hardly possible to observe traffic behavior under the most relevant condition of an accident occurring, because accidents are very rare events, given the large number of trips. Given the new video equipment and the recent developments in automatic incident and accident detection, it becomes more and more realistic to collect such data at not too high costs. Additional to this type of data that is most essential for a good understanding of the risk increasing factors in traffic, it also important to look at normal traffic behavior as a reference base. The question about the possibilities and limitations of accident analysis is not lightly answered. We cannot speak unambiguously about accident analysis. Accident analysis covers a whole range of activities, each originating from a different background and based on different sources of information: national data banks, additional information from other sources, especially collected accident data, behavioral background data etc. To answer the question about the possibilities and limitations, we first have to look at the cycle of activities in the area of traffic safety. Some ofthese activities are mainly concerned with the safety management of the traffic system; some others are primarily research activities.The following steps should be distinguished:- detection of new or remaining safety problems;- description of the problem and its main characteristics;- the analysis of the problem, its causes and suggestions for improvement;- selection and implementation of safety measures;- evaluation of measures taken.Although this cycle can be carried out by the same person or group of persons, the problem has a different (political/managerial or scientific) background at each stage. We will describe the phases in which accident analysis is used. It is important to make this distinction. Many fruitless discussions about the method of analysis result from ignoring this distinction. Politicians, or road managers are not primarily interested in individual accidents. From their perspective accidents are often treated equally, because the total outcome is much more important than the whole chain of events leading to each individual accident. Therefore, each accident counts as one and they add up all together to a final safety result.Researchers are much more interested in the chain of events leading to an individual accident. They want to get detailed information abouteach accident, to detect its causes and the relevant conditions. The politician wants only those details that direct his actions. At the highest level this is the decrease in the total number of accidents. The main source of information is the national database and its statistical treatment. For him, accident analysis is looking at (subgroups of) accident numbers and their statistical fluctuations. This is the main stream of accident analysis as applied in the area of traffic safety. Therefore, we will first describe these aspects of accidents.2. The nature of accidents and their statistical characteristics.The basic notion is that accidents, whatever there cause, appear according to a chance process. Two simple assumptions are usually made to describe this process for (traffic) accidents:- the probability of an accident to occur is independent from the occurrence of previous accidents;-the occurrence of accidents is homogeneous in time.If these two assumptions hold, then accidents are Poisson distributed. The first assumption does not meet much criticism. Accidents are rare events and therefore not easily influenced by previous accidents. In some cases where there is a direct causal chain (e.g. , when a number of cars run into each other) the series of accidents may be regarded as one complicated accident with many cars involved.The assumption does not apply to casualties. Casualties are often related to the same accident andtherefore the independency assumption does not hold. The second assumption seems less obvious at first sight. The occurrence of accidents through time or on different locations are not equally likely. However, the assumption need not hold over long time periods. It is a rather theoretical assumption in its nature. If it holds for short periods of time, then it also holds for long periods, because the sum of Poisson distributed variables, even if their Poisson rates are different, is also Poisson distributed. The Poisson rate for the sum of these periods is then equal to the sum of the Poisson rates for these parts.The assumption that really counts for a comparison of (composite) situations, is whether two outcomes from an aggregation of situations in time and/or space, have a comparable mix of basic situations. E.g. , the comparison of the number of accidents on one particular day of the year, as compared to another day (the next day, or the same day of the next week etc.). If the conditions are assumed to be the same (same duration, same mix of traffic and situations, same weather conditions etc.) then the resulting numbers of accidents are the outcomes of the same Poisson process. This assumption can be tested by estimating the rate parameter on the basis of the two observed values (the estimate being the average of the two values). Probability theory can be used to compute the likelihood of the equality assumption, given the two observations and their mean.This statistical procedure is rather powerful. The Poisson assumptionis investigated many times and turns out to be supported by a vast body of empirical evidence. It has been applied in numerous situations to find out whether differences in observed numbers of accidents suggest real differences in safety. The main purpose of this procedure is to detect differences in safety. This may be a difference over time, or between different places or between different conditions. Such differences may guide the process of improvement. Because the main concern is to reduce the number of accidents, such an analysis may lead to the most promising areas for treatment. A necessary condition for the application of such a test is, that the numbers of accidents to be compared are large enough to show existing differences. In many local cases an application is not possible. Accident black-spot analysis is often hindered by this limitation, e.g., if such a test is applied to find out whether the number of accidents at a particular location is higher than average. The procedure described can also be used if the accidents are classified according to a number of characteristics to find promising safety targets. Not only with aggregation, but also with disaggregation the Poisson assumption holds, and the accident numbers can be tested against each other on the basis of the Poisson assumptions. Such a test is rather cumbersome, because for each particular case, i.e. for each different Poisson parameter, the probabilities for all possible outcomes must be computed to apply the test. In practice, this is not necessary when the numbers are large. Then the Poissondistribution can be approximated by a Normal distribution, with mean and variance equal to the Poisson parameter. Once the mean value and the variance of a Normal distribution are given, all tests can be rephrased in terms of the standard Normal distribution with zero mean and variance one. No computations are necessary any more, but test statistics can be drawn from tables.3. The use of accident statistics for traffic safety policy.The testing procedure described has its merits for those types of analysis that are based on the assumptions mentioned. The best example of such an application is the monitoring of safety for a country or region over a year, using the total number of accidents (eventually of a particular type, such as fatal accidents), in order to compare this number with the outcome of the year before. If sequences of accidents are given over several years, then trends in the developments can be detected and accident numbers predicted for following years. Once such a trend is established, then the value for the next year or years can be predicted, together with its error bounds. Deviations from a given trend can also be tested afterwards, and new actions planned. The most famous one is carried out by Smeed 1949. We will discuss this type of accident analysis in more detail later.(1). The application of the Chi-square test for interaction is generalised to higher order classifications. Foldvary and Lane (1974), inmeasuring the effect of compulsory wearing of seat belts, were among the first who applied the partitioning of the total Chi-square in values for the higher order interactions of four-way tables.(2). Tests are not restricted to overall effects, but Chi-square values can be decomposed regarding sub-hypotheses within the model. Also in the two-way table, the total Chisquare can be decomposed into interaction effects of part tables. The advantage of 1. and 2. over previous situations is, that large numbers of Chi-square tests on many interrelated (sub)tables and corresponding Chi-squares were replaced by one analysis with an exact portioning of one Chi-square.(3). More attention is put to parameter estimation. E.g., the partitioning of the Chi-square made it possible to test for linear or quadratic restraints on the row-parameters or for discontinuities in trends.(4). The unit of analysis is generalised from counts to weighted counts. This is especially advantageous for road safety analyses, where corrections for period of time, number of road users, number of locations or number of vehicle kilometres is often necessary. The last option is not found in many statistical packages. Andersen 1977 gives an example for road safety analysis in a two-way table. A computer programme WPM, developed for this type of analysis of multi-way tables, is available at SWOV (see: De Leeuw and Oppe 1976). The accident analysis at this level is not explanatory. It tries to detect safety problems that need specialattention. The basic information needed consists of accident numbers, to describe the total amount of unsafety, and exposure data to calculate risks and to find situations or (groups of) road users with a high level of risk. 4. Accident analysis for research purposes.Traffic safety research is concerned with the occurrence of accidents and their consequences. Therefore, one might say that the object of research is the accident. The researcher’s interest however is less focused at this final outcome itself, but much more at the process that results (or does not result) in accidents. Therefore, it is better to regard the critical event in traffic as his object of study. One of the major problems in the study of the traffic process that results in accidents is, that the actual occurrence is hardly ever observed by the researcher.Investigating a traffic accident, he will try to reconstruct the event from indirect sources such as the information given by the road users involved, or by eye-witnesses, about the circumstances, the characteristics of the vehicles, the road and the drivers. As such this is not unique in science, there are more examples of an indirect study of the object of research. However, a second difficulty is, that the object of research cannot be evoked. Systematic research by means of controlled experiments is only possible for aspects of the problem, not for the problem itself. The combination of indirect observation and lack of systematic control make it very difficult for the investigator to detectwhich factors, under what circumstances cause an accident. Although the researcher is primarily interested in the process leading to accidents, he has almost exclusively information about the consequences, the product of it, the accident. Furthermore, the context of accidents is complicated. Generally speaking, the following aspects can be distinguished: - Given the state of the traffic system, traffic volume and composition, the manoeuvres of the road users, their speeds, the weather conditions, the condition of the road, the vehicles, the road users and their interactions, accidents can or cannot be prevented.- Given an accident, also depending on a large number of factors, such as the speed and mass of vehicles, the collision angle, the protection of road users and their vulnerability, the location of impact etc., injuries are more or less severe or the material damage is more or less substantial. Although these aspects cannot be studied independently, from a theoretical point of view it has advantages to distinguish the number of situations in traffic that are potentially dangerous, from the probability of having an accident given such a potentially dangerous situation and also from the resulting outcome, given a particular accident.This conceptual framework is the general basis for the formulation of risk regarding the decisions of individual road users as well as the decisions of controllers at higher levels. In the mathematical formulation of risk we need an explicit description of our probability space, consistingof the elementary events (the situations) that may result in accidents, the probability for each type of event to end up in an accident, and finally the particular outcome, the loss, given that type of accident.A different approach is to look at combinations of accident characteristics, to find critical factors. This type of analysis may be carried out at the total group of accidents or at subgroups. The accident itself may be the unit of research, but also a road, a road location, a road design (e.g. a roundabout) etc.中文译文交通事故分析的可能性和局限性S.Oppe摘要交通事故的统计数字, 尤其国家一级的数据对监控和预测事故的发展, 积极或消极检测事故的发展, 以及对定义安全目标和评估工业安全特别有益。

原子核中带正电的事。

英文回答：In an atomic nucleus, there are positively charged particles called protons. Protons are one of the fundamental particles that make up an atom. They have a positive electric charge and are located in the nucleus, which is the central region of an atom. The number of protons in an atom determines its atomic number and defines the type of element it is.Protons are essential for the stability of an atom. They play a crucial role in holding the nucleus together, as they are attracted to the negatively charged particles called electrons that orbit around the nucleus. Thepositive charge of the protons balances out the negative charge of the electrons, creating an overall neutral charge for the atom.Protons also participate in the process of nuclearreactions. For example, in nuclear fusion, protons are involved in the fusion of two atomic nuclei to form a heavier nucleus. This process releases a tremendous amount of energy and is the power source of stars, including our Sun.Furthermore, protons are responsible for the phenomenon of radioactivity. Certain elements have unstable nuclei, meaning they have an excess of protons or neutrons. In order to reach a more stable state, these nuclei undergo radioactive decay, where they emit particles or energy. This decay process can be harnessed for various applications, such as medical imaging and cancer treatment.In summary, protons are positively charged particles found in the atomic nucleus. They are crucial for the stability of an atom, participate in nuclear reactions, and are involved in radioactive decay processes. Their interactions with electrons and other particles determine the properties and behavior of different elements.中文回答：原子核中带有正电的粒子被称为质子。

中英文对照外文翻译(文档含英文原文和中文翻译)外文文献17In the first book we considered the idea merely as such, that is, only according to its general form. It is true that as far as the abstract idea, the concept, is concerned, we obtained a knowledge of it in respect of its content also, because it has content and meaning only in relation to the idea of perception, with out which it would be worthless and empty. Accordingly, directing our attention exclusively to the idea of perception, we shall now endeavour to arrive at a knowledge of its content, its more exact definition, and the forms which it presents to us. And it will specially interest us to find an explanation of its peculiar significance, that significance which is otherwise merely felt, but on account of which it is that these pictures do not pass by us entirely strange and meaningless, as they must other wise do, but speak to us directly, are understood, and obtain an interest which concerns our whole nature.We direct our attention to mathematics, natural science, and philosophy, for each of these holds out the hope that it will afford us a part of the explanation we desire. Now, taking philosophy first, we find that it is like a monster with many heads, each of which speaks a different language. They are not, indeed, all at variance on the point we are here considering, the significance of the idea of perception. For, with the exception of the Sceptics and the Idealists, the others, for the most part, speak very much in the same way of an object which constitutes the basis of the idea, and which is indeed different in its whole being and nature from the idea, but yet isin all points as like it as one egg is to another. But this does not help us, for we are quite unable to distinguish such an object from the idea; we find that they are one and the same; for every object always and for ever presupposes a subject, and therefore remains idea, so that we recognised objectivity as belonging to the most universal form of the idea, which is the division into subject and object. Further, the principle of sufficient reason, which is referred to in support of this doctrine, is for us merely the form of the idea, the orderly combination of one idea with another, but not the combination of the whole finite or infinite series of ideas with something which is not idea at all, and which cannot therefore be presented in perception. Of the Sceptics and Idealists we spoke above, in examining the controversy about the reality of the outer world.If we turn to mathematics to look for the fuller knowledge we desire of the idea of perception, which we have, as yet, only understood generally, merely in its form, we find that mathematics only treats of these ideas so far as they fill time and space, that is, so far as they are quantities. It will tell us with the greatest accuracy thehow-many and the how-much; but as this is always merely relative, that is to say, merely a comparison of one idea with others, and a comparison only in the one respect of quantity, this also is not the information we are principally in search of.Lastly, if we turn to the wide province of natural science, which is divided into many fields, we may, in the first place, make a general division of it into two parts. It is either the description of forms, which I call Morphology, or the explanation of changes, which I call Etiology. The first treats of the permanent forms, the second of the changing matter, according to the laws of its transition from one form to another.The first is the whole extent of what is generally called natural history. It teaches us, especially in the sciences of botany and zoology, the various permanent, organised, and therefore definitely determined forms in the constant change of individuals; and these forms constitute a great part of the content of the idea of perception. In natural history they are classified, separated, united, arranged according to natural and artificial systems, and brought under concepts which make a general view and knowledge of the whole of them possible. Further, an infinitely fine analogy both in the whole and in the parts of these forms, and running through them all (unité de plan), is established, and thus they may be com pared to innumerable variations on a theme which is not given. The passage of matter into these forms, that is to say, the origin of individuals, is not a special part of natural science, for every individual springs from its like by generation, which is everywhere equally mysterious, and has as yet evaded definite knowledge. The little that is known on the subject finds its place in physiology, which belongs to that part of natural science I have called etiology. Mineralogy also, especially where it becomes geology, inclines towards etiology, though it principally belongs to morphology. Etiology proper comprehends all those branches of natural science in which the chief concern is the knowledge of cause and effect. The sciences teach how, according to an invariable rule, one condition of matter is necessarily followed by a certain other condition; how one change necessarily conditions and brings about a certain other change; this sort of teaching is called explanation. The principal sciences in this department are mechanics, physics, chemistry, and physiology.If, however, we surrender ourselves to its teaching, we soon become convinced that etiology cannot afford us the information we chiefly desire, any more than morphology. The latter presents to us innumerable and in finitely varied forms, which are yet related by an unmistakable family likeness. These are for us ideas, and when only treated in this way, they remain always strange to us, and stand before us like hieroglyphics which we do not understand. Etiology, on the other hand, teaches us that, according to the law of cause and effect, this particular condition of matter brings about that other particular condition, and thus it has explained it and performed its part. However, it really does nothing more than indicate the orderlyarrangement according to which the states of matter appear in space and time, and teach in all cases what phenomenon must necessarily appear at a particular time in a particular place. It thus determines the position of phenomena in time and space, according to a law whose special content is derived from experience, but whose universal form and necessity is yet known to us independently of experience. But it affords us absolutely no information about the inner nature of any one of these phenomena: this is called a force of nature, and it lies outside the province of causal explanation, which calls the constant uniformity with which manifestations of such a force appear whenever their known conditions are present, a law of nature. But this law of nature, these conditions, and this appearance in a particular place at a particular time, are all that it knows or ever can know. The force itself which manifests itself, the inner nature of the phenomena which appear in accordance with these laws, remains always a secret to it, something entirely strange and unknown in the case of the simplest as well as of the most complex phenomena. For although as yet etiology has most completely achieved its aim in mechanics, and least completely in physiology, still the force on account of which a stone falls to the ground or one body repels another is, in its inner nature, not less strange and mysterious than that which produces the movements and the growth of an animal. The science of mechanics presupposes matter, weight, impenetrability, the possibility of communicating motion by impact, inertia and so forth as ultimate facts, calls them forces of nature, and their necessary and orderly appearance under certain conditions a law of nature. Only after this does its explanation begin, and it consists in indicating truly and with mathematical exactness, how, where and when each force manifests itself, and in referring every phenomenon which presents itself to the operation of one of these forces. Physics, chemistry, and physiology proceed in the same way in their province, only they presuppose more and accomplish less. Consequently the most complete etiological explanation of the whole of nature can never be more than an enumeration of forces which cannot be explained, and a reliable statement of the rule according to which phenomena appear in time and space, succeed, and make way for each other. But the inner nature of the forces which thus appear remains unexplained by such an explanation, which must confineitself to phenomena and their arrangement, because the law which it follows does not extend further. In this respect it may be compared to a section of a piece of marble which shows many veins beside each other, but does not allow us to trace the course of the veins from the interior of the marble to its surface. Or, if I may use an absurd but more striking comparison, the philosophical investigator must always have the same feeling towards the complete etiology of the whole of nature, as a man who, without knowing how, has been brought into a company quite unknown to him, each member of which in turn presents another to him as his friend and cousin, and therefore as quite well known, and yet the man himself, while at each introduction he expresses himself gratified, has always the question on his lips: "But how the deuce do I stand to the whole company?"Thus we see that, with regard to those phenomena which we know only as our ideas, etiology can never give us the desired information that shall carry us beyond this point. For, after all its explanations, they still remain quite strange to us, as mere ideas whose significance we do not understand. The causal connection merely gives us the rule and the relative order of their appearance in space and time, but affords us no further knowledge of that which so appears. Moreover, the law of causality itself has only validity for ideas, for objects of a definite class, and it has meaning only in so far as it presupposes them. Thus, like these objects themselves, it always exists only in relation to a subject, that is, conditionally; and so it is known just as well if we start from the subject, i.e., a priori, as if we start from the object, i.e., a posteriori. Kant indeed has taught us this.But what now impels us to inquiry is just that we are not satisfied with knowing that we have ideas, that they are such and such, and that they are connected according to certain laws, the general expression of which is the principle of sufficient reason. We wish to know the significance of these ideas; we ask whether this world is merely idea; in which case it would pass by us like an empty dream or a baseless vision, not worth our notice; or whether it is also something else, something more than idea, and if so, what. Thus much is certain, that this something we seek for must be completely and in its whole nature different from the idea; that the forms and laws of the idea must therefore be completely foreign to it; further, thatwe cannot arrive at it from the idea under the guidance of the laws which merely combine objects, ideas, among themselves, and which are the forms of the principle of sufficient reason.Thus we see already that we can never arrive at the real nature of things from without. However much we investigate, we can never reach anything but images and names. We are like a man who goes round a castle seeking in vain for an entrance, and sometimes sketching the façades. And yet this is the method that has been followed by all philosophers before me.18In fact, the meaning for which we seek of that world which is present to us only as our idea, or the transition from the world as mere idea of the knowing subject to whatever it may be besides this, would never be found if the investigator himself were nothing more than the pure knowing subject (a winged cherub without a body). But he is himself rooted in that world; he finds himself in it as an individual, that is to say, his knowledge, which is the necessary supporter of the whole world as idea, is yet always given through the medium of a body, whose affections are, as we have shown, the starting-point for the understanding in the perception of that world. His body is, for the pure knowing subject, an idea like every other idea, an object among objects. Its movements and actions are so far known to him in precisely the same way as the changes of all other perceived objects, and would be just as strange and incomprehensible to him if their meaning were not explained for him in an entirely different way. Otherwise he would see his actions follow upon given motives with the constancy of a law of nature, just as the changes of other objects follow upon causes, stimuli, or motives. But he would not understand the influence of the motives any more than the connection between every other effect which he sees and its cause. He would then call the inner nature of these manifestations and actions of his body which he did not understand a force, a quality, or a character, as he pleased, but he would have no further insight into it. But all this is not the case; indeed, the answer to the riddle is given to the subject of knowledge who appears as an individual, and the answer is will. This and this alone gives him the key to his own existence, reveals to him the significance, shows him the inner mechanism of hisbeing, of his action, of his movements. The body is given in two entirely different ways to the subject of knowledge, who becomes an individual only through his identity with it. It is given as an idea in intelligent perception, as an object among objects and subject to the laws of objects. And it is also given in quite a different way as that which is immediately known to every one, and is signified by the word will. Every true act of his will is also at once and without exception a movement of his body. The act of will and the movement of the body are not two different things objectively known, which the bond of causality unites; they do not stand in the relation of cause and effect; they are one and the same, but they are given in entirely different ways, — immediately, and again in perception for the understanding. The action of the body is nothing but the act of the will objectified, i.e., passed into perception. It will appear later that this is true of every movement of the body, not merely those which follow upon motives, but also involuntary movements which follow upon mere stimuli, and, indeed, that the whole body is nothing but objectified will, i.e., will become idea. All this will be proved and made quite clear in the course of this work. In one respect, therefore, I shall call the body the objectivity of will; as in the previous book, and in the essay on the principle of sufficient reason, in accordance with the one-sided point of view intentionally adopted there (that of the idea), I called it the immediate object. Thus in a certain sense we may also say that will is the knowledge a priori of the body, and the body is the knowledge a posteriori of the will. Resolutions of the will which relate to the future are merely deliberations of the reason about what we shall will at a particular time, not real acts of will. Only the carrying out of the resolve stamps it as will, for till then it is never more than an intention that may be changed, and that exists only in the reason in abstracto. It is only in reflection that to will and to act are different; in reality they are one. Every true, genuine, immediate act of will is also, at once and immediately, a visible act of the body. And, corresponding to this, every impression upon the body is also, on the other hand, at once and immediately an impression upon the will. As such it is called pain when it is opposed to the will; gratification or pleasure when it is in accordance with it. The degrees of both are widely different. It is quite wrong, however, to call pain and pleasure ideas, for they are by no meansideas, but immediate affections of the will in its manifestation, the body; compulsory, instantaneous willing or not-willing of the impression which the body sustains. There are only a few impressions of the body, which do not touch the will, and it is through these alone that the body is an immediate object of knowledge, for, as perceived by the understanding, it is already an indirect object like all others. These impressions are, therefore, to be treated directly as mere ideas, and excepted from what has been said. The impressions we refer to are the affections of the purely objective senses of sight, hearing, and touch, though only so far as these organs are affected in the way which is specially peculiar to their specific nature. This affection of them is so excessively weak an excitement of the heightened and specifically modified sensibility of these parts that it does not affect the will, but only furnishes the understanding with the data out of which the perception arises, undisturbed by any excitement of the will. But every stronger or different kind of affection of these organs of sense is painful, that is to say, against the will, and thus they also belong to its objectivity. Weakness of the nerves shows itself in this, that the impressions which have only such a degree of strength as would usually be sufficient to make them data for the understanding reach the higher degree at which they influence the will, that is to say, give pain or pleasure, though more often pain, which is, however, to some extent deadened and inarticulate, so that not only particular tones and strong light are painful to us, but there ensues a generally unhealthy and hypochondriacal disposition which is not distinctly understood. The identity of the bodv and the will shows itself further, among other ways, in the circumstance that every vehement and excessive movement of the will, i.e., every emotion, agitates the body and its inner constitution directly, and disturbs the course of its vital functions. This i s shown in detail in “Will in Nature” p. 27 of the second edition and p.28 of the third.外文文献翻译：17在第一篇里我们只是把表象作为表象，从而也只是在普遍的形式上加以考察。

毕业设计毕业论文电气工程及其自动化外文翻译中英文对照电气工程及其自动化外文翻译中英文对照一、引言电气工程及其自动化是一门涉及电力系统、电子技术、自动控制和信息技术等领域的综合学科。

本文将翻译一篇关于电气工程及其自动化的外文文献，并提供中英文对照。

二、文献翻译原文标题：Electric Engineering and Its Automation作者：John Smith出版日期：2020年摘要：本文介绍了电气工程及其自动化的基本概念和发展趋势。

首先，介绍了电气工程的定义和范围。

其次，探讨了电气工程在能源领域的应用，包括电力系统的设计和运行。

然后，介绍了电气工程在电子技术领域的重要性，包括电子设备的设计和制造。

最后，讨论了电气工程与自动控制和信息技术的结合，以及其在工业自动化和智能化领域的应用。

1. 介绍电气工程是一门研究电力系统和电子技术的学科，涉及发电、输电、配电和用电等方面。

电气工程的发展与电力工业的发展密切相关。

随着电力需求的增长和电子技术的进步，电气工程的重要性日益凸显。

2. 电气工程在能源领域的应用电气工程在能源领域的应用主要包括电力系统的设计和运行。

电力系统是由发电厂、输电线路、变电站和配电网络等组成的。

电气工程师负责设计和维护这些设施，以确保电力的可靠供应。

3. 电气工程在电子技术领域的重要性电气工程在电子技术领域的重要性体现在电子设备的设计和制造上。

电子设备包括电脑、手机、电视等消费电子产品，以及工业自动化设备等。

电气工程师需要掌握电子电路设计和数字信号处理等技术，以开发出高性能的电子设备。

4. 电气工程与自动控制和信息技术的结合电气工程与自动控制和信息技术的结合是电气工程及其自动化的核心内容。

自动控制技术可以应用于电力系统的运行和电子设备的控制，以提高系统的稳定性和效率。

信息技术则可以用于数据采集、处理和传输，实现对电力系统和电子设备的远程监控和管理。

5. 电气工程在工业自动化和智能化领域的应用电气工程在工业自动化和智能化领域的应用越来越广泛。

Research on Competency Model:A Literature Review andEmpirical StudiesAbstractWestern countries have applied competency models to addressing problems existed in their administrative and managerial systems since 1970s，and the findings is positine and promising. However, competency model hasn’t been introduced to China until 1990s and it is still unknown and mysterious to many Chinese managers. This paper aims to uncover the mysterious veil of competency model in order to broaden the horizon of Chinese managers and boost China's human resource development as well as management.Keywords:Competency，Competency Models，Empirical Studies of Competency ModelsIt has been more than 30 years since competency model was utilized to human resource management.In western countries，competency model first displayed its effectiveness in government administration, meanwhile many multinationals and their branch companies applied the competency model to their daily business management and their business was a great success. As the notion of competency is gradually come to light and accepted by people all around the world，more and more enterprises have been trying to build their own competency model under the help of professional consultant firms. As a result，competency model has gradually been a very fashionable phrase in the field of management and quite a few enterprises are thus benefited from it. In recent years, competency model has become a hot spot in the Chinese academia as well as big-，middle- and small-sized enterprises alike，many relevant writings and books have also been translated and published. However, competency and competency model are still mysterious to many Chinese scholars, business managers as well as government administrators.Purpose and Significance of the StudyThe purpose of the study aims to make a critical literature review of the competency model，clarify some confusion related to it and explore its application. The following questions are employed to guide this study:What is competency? What is competency model? What are the theoretical and empirical findings related to competency model?The study illustrates how we could take advantage of competency model in our harmonious society building. On one hand，the study will delineate competency and competency model in order to clarify confusions related to it since it is still strange and mysterious to many Chinese managers and administrators;on the other hand，thestudy would enrich Chinese HRD&HRM in the field of government administration and business management both theoretically and empirically.Research MethodThe present study has utilized qualitative analysis, induction and deduction. Since this research is a literature review in some sense, qualitative analysis will be an indispensable research method; Induction and deduction are applied to both theoretical and empirical studies.In order to enhance the credibility of present research，only the authoritative publications on competency model are reviewed，including books and papers written by foreign and Chinese scholars and HRDHRM practitioners. By searching for the keywords "competency" "competency model" and "competency model building" as well as "empirical studies on competency models"，books and papers written by well-known foreign scholars such as McClelland D. C.，Lyle M. Spencer, Anntoinette D. Lucia, Richard Lepsinger etc.，are available; by the same token，books and papers written by Chinese scholars such as Zhi-gong He，Jianfeng Peng, Shaohua Fang, Nengquan Wu，etc.，could be consulted. All the books and papers are published between 1950s and 2007. In addition, many data cited in this paper comes from empirical studies at home and abroad.FindingsIn this part，a literature review of competency is firstly carried out;then competency model as well as its evolution，development and innovation is delineated;finally empirical studies are reviewed. Empirical studies mainly focus on competency model building and its application to human resource development and management.Understanding CompetencyIn 1973，American scholar David C. McClelland published his paper Testing for Competency Rather Than Intelligence which cited a large amount of research findings to illustratethe inappropriateness of assessing personnel qualities by abusing intelligence tests. Dr. McClelland further explained that some factors (personality, intelligence, value，etc.)which people had always taken for granted in determining work performance hadn't displayed their desired result. As a result，he emphasized that people should ignore those theoretical by pothese and subjective judgements which had been proved groundless in reality. He declared that people should tap directly those factors and behaviors which could really impact their performance (McClelland, 1973). These factors and behaviors were named "competency" by McClelland. The publishing of this paper symbolized the debut of competency research. From then on，many scholars started getting involved into the research on competency and they conceptualizedcompetency from different perspectives as shown in the following table: The above ten concepts of competency have a lot in common:①Competency is motive, trait，value，skill，self-image, social role，knowledge;②Competency is a combination;③Competency should be measurable, observable, instructional，phasic and hierarchical;④Competency is a determinant to outstanding performance.Thus competency is an underlying combination of individual characteristics such as motive, inner drive force, quality, attitude，sole role，self-image, knowledge and skill，it is causally related to criterion-referenced effective and/or superior performance in a job or situation and it is measurable，observable and instructional.Besides，many scholars and consultancy firms believe that competency could be explained under the help of three different models:Iceberg Model. This model treats competency as an iceberg, the part above the water represents behavior, knowledge and skills which are easy to measure and observe，while the part under the water symbolizes underlying qualities such as value，attitude，social role, self-image，traits which are hard to assess，and the deepest part under the water represents the most latent qualities such as inner drive force，social motive, etc. which are most difficult to observe and measure.Onion Model. This model treats competency as an onion, the outer layer represents skills and knowledge which are liable to acquire，the inner layer refers to qualities such as self-image，social role，attitude and value which are relatively difficult to appraise, while the core of the onion symbolizes traits and motives which are most difficult to cultivate and develop.Brain Model. This model stems from the brain mechanism. It presupposes that the brain could be divided into four parts. Each part functions differently. The upper-left part is in charge of competency such as analysing capacity, calculation, strong logic ability; the upper-right part is in charge of competency such as innovation and intuition;the bottom left part is in charge of competency such as organizing ability, planning ability; and the bottom-right part is in charge of competency such as communication ability，perception, etc. Different parts will exert corresponding influence on competency development.Conceptualizations of Competency ModelFew foreign scholars have directly put forward conceptualizations of competency model. By contrast，many Chinese scholars have expressed their opinions on it. The present paper only cites those concepts that have been published by authoritative publishing houses.Jianfeng Peng, a professor in Ch;na Renmin University，together with his students, has studied how to build competency models for effective HR management since 2003. He thought competency model was the combination of differentqualities which were necessary for people to successfully finish a job or achieve superior performance，these qualities included different motives，traits, self-images and social roles as well as knowledge and skill (Jianfeng Peng, 2003). Prof. Peng believed that a competency model was composed of 4-6 competencies that were closely related to performance. Competency models could help managers judge and distinguish key factors that led to superior performance or underperformance. As a result，competency model could be treated as a foundation to improve performance.Professor Nengquan Wu from Sun Yat-sen University published his book Competency Model:Design and Application in 2005，according to his understanding, competency model refers to "proficiencies that people define core competencies of different levels, delineate corresponding behaviors，determine key competencies as well as f inish certain work.”(Nengquan Wu，2005). Prof. Wu conceptualized competency model from the perspective of methodology. He believed that competency model was a unique HRM thinking mode, method and operation flow. On the basis of organizational strategy, competency model could be utilized to enhance organizational competitiveness and improve performance.Shaohua Fang, a senior HRM consultant and expert，provided us with the following definition:"Competency model is to conceptualize and describe the necessary knowledge,skills，qualities and abilities which an employee should have in order to finish work (Shaohua Fang, 2007)”.By taking advantage of definitions of different levels and related behavioral descriptions, people could determine the combination of core competencies and required proficiency to finish work. Hc} pointed out these behaviors and skills must be able to measure，observe and instruct and they should exert a great influence upon personal performance and business success.International Human Resource Institute(IHRI) has also defined competency model:"The so-called competency model is the standardized description and explanation of competencies that could actualize superior performance.”(·IHRI, 2005)IHRI declared that a competency model should include 6^-1 2 competencies.In summary, the first concept mentioned above attaches an importance to the composition of competency model and its function, while all of the rest three concepts emphasize cognitive abilities as well as criterion-referred performance. Thus competency, model is a combination of different competencies which could be observed，delineated，explained and calculated on one hand，and could facilitate superior performance on the other hand.Development and Evolution of Competency ModelIn early 1970, top officials in U. S. Department of State believed that theirdiplomats' se- lection based on intelligence test was ineffective. It was an upset situation for them to find that many seemly excellent people fail to live up to their expectations regarding their work performance. Under such circumstances, Dr. McClelland was invited to help Department of State design an effective personnel selection system which could appraise the actual performance of employees. In that program，McClelland and his colleague Charles Dailey adopted the method of Behavioral Event Interview (BEI) to collect information in older to study factors that influenced the diplomats' performance. Through a series of summaries and analyses, McClelland and Dailey found out the differences between an excellent diplomat and a mediocre diplomat as far as their behaviors and modes of thinking were concerned. In this way, competencies that a diplomat should possess were found out. This program is the earliest empirical application of competency model. And the research findings were two papers: Improving Officer Selection for the Foreign Service (McClelland&Dailey，1972) as well as Evaluating New Methods of Measuring the Qualities Needed in Superior Foreign Service Information Officers(McClelland& Dailey，1973).Mcber and American Management Association (A'MA) also started their research on competency model in the same year. They focused on providing the answer to the question:what kind of competencies should be displayed by successful managers rather than unsuccessful ones? AMA spent 5 years observing 1 800 managers. By comparing the performance of excellent managers and mediocre ones, AMA defined their competencies based on their traits. The research results showed that all the successful managers shared the following 5 competencies:professional knowledge，maturity of mentality, maturity of .entrepreneurship，people relations and maturity of the profession. Of which，only professional knowledge were shared by excellent and mediocre managers (Mcber&.AMA, 1970).Then Prof. Bray carried out 8 years research at AT&T based on technique of assessment center. From the aspectives of abilities, attitudes and traits, etc.，he built a competency model composed of 25 competencies such as interpersonal relations, expression ability, social sensitivity, creativity，flexibility，organizational ability，planning ability, decision-making ability, etc(Bray and Grant，1978).In China，however, researches on competency model are relatively much late.Chinese scholars Chongming Wang and Minke Chen published their paper about competency model in Psychological Science in 1992. They studied 220 senior and middle-level managers of 51 enterprises in 5 cities. After examining and testing the competency model for senior managers on the basis of factor analysis and structural equation modelling, they compiled "Key Managerial Behavior Assessment Scale" (Chongming Wang&Minke Chen，2002).Scholars such as Kan Shi, Jicheng Wang and Chaoping Li took advantage of Behaviocal Event Interview to assess the competency model for senior managers in the industry of telecommunication (Kan Shi，Jicheng Wang&Chaoping Li，2002). Jicheng Wang designed 5 universal competency models for technical personnel，sales people, community service personnel，managers as well as entrepreneurs respectively.Jianfeng Peng and his postgraduate student Xiaojuan Xing built 4 universal competency models for business managers，business technical personnel，marketing personnel as well as HR managers (Jianfeng Peng，2003 ).The above domestic studies illustrate that competency models for middle-level and senior managers have been built based on in-depth interview and questionnairing. Most publications only focus on conceptualizing competency model，its development，behavioral event interview as well as competency model building，most of the findings are theoretical rather than empirical. By contrast，foreign studies are much maturer both theoretically and empirically.Empirical StudiesEmpirical studies highlight the application of competency model to enterprises, governments and other institutions.Nowadays，empirical studies on competency models mainly focus on the following 4 aspects:Staffing and Selection. Besides job standards and skills prescription, more and more businesses have carried out their personnel staffing and selection in light of the candidates' competencies which are crucial to their future performance. This competency-based personnel staffing and selection has connected business strategies and targets to business employees themselves. As a result，the quality of staffing and selection is greatly improved.Performance Management. Businesses which have built their competency models are more interested in the competency rather than the result itself in their performance management. As a result, their performance management style has been competency-driven rather than result-driven. Managers haven’t attached an importance to short-term performance, but current and long-term performances. In such a managerial system，outstanding performance has been easily actualized. Each employee has made most of their core competencies and expertise to make a contribution to their business.Compensation Management.After the competency-based compensation management system is set up, businesses have concentrated on their employees’future development and potential value, which has stimulated employees and managers of all ranks to improve themselves both menetuacy and teconologcal. Competency oases compense lion management system has helped enterprises attract and retain moretalents. In a word，competency model has endowed employees with a sense of respect and creativity.Training and Development. Enterprises which have built their competency models tend to determine core competencies in light of business strategies，environments, employee development planning and performance appraisal. Enterprises decide their training and development priorities on the basis of competency model.Future TrendsDespite that there is a growing body of literature on competency model，research on competency model is still in a premature stage and many questions still remain unanswered. Therefore, further research is required to address several important issues.First of all，although there are growing studies on the impacts of the competency model on organizational outcomes，antecedents of competency model need to be identified and academically explored. Future studies are needed to examine the relationships between the features of competency model and its key antecedent variables such as organizational sttracture.leadership and external environment. For example，it can be reasoned that the features of competency model are likely to be positively correlated with the structures of enterprises, governments as well as other institutions. Secondly，the impact of competency model on performance needs to be thoroughly explored. More studies are needed to examine whether the features of competency model or organizational culture，has direct or indirect impacts on organizational performance. While quite a few HRD and HRM researchers and practitioners have demonstrated that the concept of competency model has a positive impact on organizational performance, however，such impact may be mediated by other important organizational variables. Finally, it is also important to consider the relationships of competency model and other important HR variables such as career development, managerial coaching as well as employee training.Conclusions and DiscussionsIn conclusion，competency model has increasingly exerted profound influence on human resource development and management. While this concept has received an increase in both academic and management fields，there are increasing empirical studies designed to examine the nature of the construct and its relationships with other important organizational variables. More studies are needed to enhance the theoretical and empirical foundations of competency model.胜任力模型研究：文献综述和实证研究摘要20世纪70年代以来，西方国家已经利用胜任力模型来解决存在于行政和管理系统中的问题，其结果是积极且有前途的。

英文原文Theory of ionization processes in positron–atom collisions AbstractWe review past and present theoretical developments in the description of ionization processes in positron–atom collisions. Starting from an analysis that incorporates all the interactions in the final state on an equal footing and keeps an exact account of the few-body kinematics, we perform a critical comparison of different approximations, and how they affect the evaluation of the ionization cross section. Finally, we describe the appearance of fingerprints of capture to the continuum, saddle-point and other kinematical mechanisms.Keywords: Ionization; Collision dynamics; Scattering; Electron spectra; Antimatter; Positron impact; Saddle-point electrons; Wannier; CDWPACS classification codes: 34.10.+x; 34.50.Fa1. IntroductionThe simple ionization collision of a hydrogenic atom by the impact of a structureless particle, the “three-body problem”, is one of the oldest unsolved problems in physics. The two-body problem was analyzed by Johannes Kepler in 1609 and solved by Isaac Newton in 1687. The three-body problem, on the other hand, is much more complicated and cannot be solved analytically, except in some particular cases. In 1765, for instance, Leonhard Euler discovered a “collinear” solution in which three masses start in a line and remain lined-up. Some years later, Lagrange discovered the existence of five equilibrium points, known as the Lagrange points. Even the most recent quests for solutions of the three-body scattering problem use similar mathematical tools and follow similar paths than those travelled by astronomers and mathematicians in the past three centuries. For instance, in the center-of-mass reference system, we describe the three-body problem by any of the three possible sets of the spatial coordinates already introduced by Jacobi in 1836. All these pairs are related by lineal point canonical transformations, as described in [1]. In momentum space, the system is described by the associated pairs (k T,K T), (k P,K P) and (k N,K N). Switching to the Laboratory reference frame, the final momenta of the electron of mass m, the (recoil) target fragment of mass M T and the projectile of mass M P can be written in terms of the Jacobi impulses K j by means of Galilean transformations [1]For decades, the theoretical description of ionization processes has assumed simplifications of the three-body kinematics in the final state, based on the fact that• in an ion–atom collision, one particle (the electron) is much lighter than the other two,• in an electron–atom or positron–atom collision, one particle (the target nucleus) is much heavier than the other two.For instance, based on what is known as Wick’s argument, the overwhelming majority of the theoretical descriptions of ion–atom ionization collisions uses an impact-parameter approximation, where the projectile follows an undisturbed straight line trajectory throughout the collision process, and the target nucleus remains at rest [2]. It is clear that to assume that the projectile follows a straight line trajectory makes no sense in the theoretical description of electron or positron–atom collisions. However, it is usually assumed that the target nucleus remains motionless.These simplifications of the problem were introduced in the eighteenth century. The unsolvable three-body problem was simplified, to the so-called restricted three-body problem, where one particle is assumed to have a mass small enough not to influence the motion of the other two particles. Though introduced as a means to provide approximate solutions to systems such as Sun–planet–comet within a Classical Mechanics framework, it has been widely used in atomic physics in the so-called impact-parameter approximation to ion–atom ionization collisions. Another simplification of the three-body problem widely employed in the nineteenth century assumes that one of the particles is much more massive than the other two and remains in the center of mass unperturbed by the other two. This approximation has been widely used in electron–atom or positron–atom ionization collisions.2. The multiple differential cross sectionA kinematically complete description of a three-body continuum final-state in any atomic collision would require, in principle, the knowledge of nine variables, such as the components of the momenta associated to each of the three particles in the final state. However, the condition of momentum and energy conservation reduces this number to five. Furthermore, whenever the initial targets are not prepared in any preferential direction, the multiple differential cross section has to be symmetric by a rotation of the three-body system around the initial direction of motion of the projectile. Thus, leaving aside the internal structure of the three fragments in the final state, only four out of nine variables are necessary to completely describe the scattering process. Therefore, a complete characterization of the ionization process may be obtained with a quadruple differential cross section:There are many possible sets of four variables to use. For, instance, we can chose azimuthal angles of the electron and of one of the other two particles, the relative angle between the planes of motion, and the energy of one particle.Such a choice is arbitrary, but complete in the sense that any other set of variables can be related to this one. A similar choice of independent variables has been standard for the description of atomic ionization by electron impact, both theoretically and experimentally [3] and [4].A picture of the very general quadruple differential cross section is not feasible. Thus, it is usually necessary to reduce the number of variables in the cross section. This can be achieved by fixing one or two of them at certain particular values or conditions. For instance, we might arbitrarily restrict ourselves to describe a coplanar (i.e. = 0) or a collinear motion (i.e. = 0 and θ1 = θ2), so as to reduce the dependence of the problem to three or two independent variables, respectively. The other option is to integrate the quadruple differential cross section over one or more variables.The former has been widely used to study electron–atom collisions, while the latter has been the main tool to characterize ion–atom and positron–atom ionization collisions. Particularly important has been the use of single particle spectroscopy, where the momentum of one of the particles is measured.3. Single particle momentum distributionsIn ionization by positron impact it is feasible to study the momentum distribution of any of the involved fragments. As is shown in Fig. 1, the momentum distributions for the emitted electron and the positron present several structures. First, we can observe a threshold at high electron or positron velocities because there is a limit in the kinetic energy that any particle can absorb from the system. The second structure is a ridge set along a circle. It corresponds to a binary collision of the positron with the emitted electron, with the target nucleus playing practically no role. Finally, there is a cusp and an anticusp at zero velocity in the electron and positron momentum distributions, respectively. The first one corresponds to the excitation of the electron to a low-energy continuum state of the target. The second is a depletion due to the impossibility of capture of the positron by the target nucleus. These momentum distributions allow us to study the main characteristics of ionization collisions. However, we have to keep in mind that any experimentaltechnique that analyzes only one of the particles in the final-state can only provide a partial insight into the ionization processes. The quadruple differential cross sections might display collision properties that are washed out by integration in this kind of experiments.Fig. 1. Electron and positron momentum distributions for theionization of helium by impact of positrons with incident velocityv = 12 a.u.4. Theoretical modelThe main question that we want to address in this communication is if there are some important collision properties in positron–atom collisions, that are not observable in total, single or double differential ionization cross sections, and that therefore have not yet been discovered. In order to understand the origin of these structures, we compare the corresponding cross sections with those obtained inion–atom collisions. To fulfill this objective it is necessary to have a full quantum-mechanical treatment able to deal simultaneously with ionization collisions by impact of both heavy and light projectiles that is therefore equally applicable – for instance – to ion–atom or positron–atom collisions. A theory with this characteristics will allow us to study the changes of any given feature of multiple-differential cross-sections when the mass relations among the fragments vary. In particular, it would allow us to study the variation when changing between the two restricted kinematical situations.The second important point is to treat all the interactions in the final state on an equal footing. As we have just explained, in ion–atom collisions, the internuclear interaction plays practically no role in the momentum distribution of the emittedelectron and has therefore not been considered in the corresponding calculation. In this work, this kind of assumption has been avoided.The cross section of interest within this framework isThe transition matrix can be alternatively written in post or prior forms aswhere the perturbation potentials are defined by (H−E)Ψi = V iΨi and (H−E)Ψf = V fΨf.For the Born-type initial statewhich includes the free motion of the projectile and the initial bound state Φi of the target, and the perturbation potential V i is simply the sum of the positron–electron and positron–nucleus interactions. The transition matrix may then be decomposed into two termsdepending on whether the positron interacts first with the target nucleus or the electron.In order to be consistent with our full treatment of the kinematics, it is necessary to describe the final state by means of a wavefunction that considers all the interactions on the same footing. Thus, we resort to a correlated C3 wave function that includes distortions for the three active interactions. The final-channelperturbation potential for this choice of continuum wave function is [5](1) In the case of pure coulomb potentials, the distortions are given bywith νj = m j Z j/k j. This model was proposed by Garibotti and Miraglia [6]for ion–atom collisions, and by Brauner and Briggs six years later for positron–atom and electron–atom collisions [7]. However, in all these cases the kinematics of the problem was simplified, as discussed in the previous section, on the basis of the large asymmetry between the masses of the fragments involved. In addition, Garibotti and Miraglia neglected the matrix element of the interaction potential between the incoming projectile and the target ion, and made a peaking approximation to evaluate the transition matrix element. This further approximation was removed in a paper by Berakdar et al. (1992), although they kept the mass restrictions in their ion-impact ionization analysis.5. The electron capture to the continuum cuspLet us review some results in a collinear geometry. We choose as the two independent parameters the emitted electron momentum components, parallel and perpendicular to the initial direction of motion of the positron projectile. The energy of the projectile is 1 keV. In Fig. 2, we observe three different structures: two minima and a ridge.Fig. 2. QDCS for ionization of H2 by impact of 1 keV positrons foremission of electrons in the direction of the projectile deflection.The origin of the ridge is very well understood. It corresponds to the electron capture to the continuum (ECC) cusp discovered in ion–atom collisions three decades ago by Crooks and Rudd [8]. They measured the electron energy spectra in the forward direction and observed a cusp-shape peak at exactly the projectile’s velocity. The first theoretical explanation [9] showed that it diverges in the same way as 1/k. This cusp structure was the focus of a large amount of experimental and theoretical research.Since the ECC cusp is an extrapolation across the ionization limit of capture into highly excited bound states, this same effect has to be present in positron–atom collisions. In fact, the observation of such an effect associated with positronium formation, while predicted two decades ago by Brauner and Briggs, remained a controversial issue. The reason for this dispute was that, in contrast to the case of ions, the positron outgoing velocity is not similar to that of impact, but is largely spread in angle and magnitude. Thus there is no particular velocity where to look for the cusp. And this is certainly so. If we evaluate the double differential cross section, we see that the cusp is clearly visible in ion–atom collisions, but just a very mild and spread shoulder in positron–atom collisions. Thus, to observe this structure it is necessary to increase the dimension of the cross section. For instance by considering a zero degree cut of the quadruple differential cross section in collinear geometry.Kover and Laricchia measured in 1998 the dσ/d E e dΩk dΩK cross section in a collinear condition at zero degree, for the ionization of H2 molecules by 100 keV positron impact [10]. The structure is not so sharply defined as for impact observed for heavy ions because of the convolution that accounts for the experimentalwindow in the positron and electron detection. Since the target recoil plays no significant role in this experimental situation, the present general theory gives results similar to those obtained by Berakdar [11], and both closely follow the experimental values.The same kind of experiment was performed by Sarkadi and coworkers in Argon ionization by 75 keV proton impact. They measured the quadruple differential ionization cross section in a collinear geometry for ion–atom collisions for the first time, and found the ECC cusp as in positron impact at large angles. In this case, we have to keep a complete account of the kinematics in order to reproduce the experimental results [12].6. Thomas mechanismLet us now go back to the ionization of H2 by 1 keV positron impact. A structure at 45° can be observed, which was predicted and explained in 1993 by Brauner and Briggs as due to the interference of two equivalent double-collision mechanisms. Each of these processes consists of a positron–electron binary collision, followed by the deflection by 90° of one of the light particles by the heavy nucleus. This mechanism was proposed by Thomas [13] as the main responsible of electron capture by fast heavy ions. In this case, since the electron and positron masses are equal, these two processes interfere at 45°.If we lower the energy from 1000 eV to 100 eV, this structure at 45° disappears, a result that is consistent with the idea that the Thomas mechanism is a high energy effect. But there is another structure, at about 22.5°, that persists. We will consider this structure in the next section.7. Saddle-point mechanismThe origin of the structure at about 22.5° is certainly more difficult to identify. To our best knowledge, it has not been predicted before in positron–atom collisions, even though the mechanism responsible of its origin was already been proposed in ion–atom collisions almost two decades before. The idea was that an electron could emerge from an ion–atom collision by lying in the saddle-point of the projectile and the residual target-ion potentials. This mechanism is clearly related to one of the equilibrium points discovered by Lagrange in 1772, or to the mechanism proposed by Wannier for low-energy electron emission. In the case of ion–atom collisions, the search for theoretical and experimental evidence of this mechanism was overcast by vivid controversy [14], [15], [16], [17] and [18].In the case of positron–atom collisions, for the electrons to be trapped in the saddle of the positron and residual-ion potentials, the electron and the positron must first perform a binary collision so as to end up with the right velocities(2)where εi is the binding energy of the target in the initial state.Application of energy and momentum conservation principles shows that the positron is deviated in an angle(3) Finally, for the electron to emerge in the same direction as the positron, it must suffer a subsequent collision with the residual-nucleus in a Thomas-like process. In this second collision, the electron is deflected by 90°and the residual target ion recoils in a direction that forms an angle of about 135° with the electron and the positron. This mechanism is depicted in Fig. 4.Thus, to check that the proposal of a saddle-point is correct, we look at whether our calculations show structures that are consistent with this description of saddle-point electron production.The minimum observed in the QDCS of Fig. 3 and Fig. 4 are located at precisely those points where the previous conditions on the energy and angle of any of the three particles are met.Fig. 3. QDCS for H2 ionization by 100 eV positrons in the restrictedcollinear geometry.Fig. 4. Mechanism proposed to lead to the observed saddle-likestructure.We made another test on the validity of the saddle-point mechanism. Fig. 5 shows that the structure arises exclusively from the t P term. This result is consistent with the proposed mechanism, where the saddle-point structure arises from a first positron–electron collision. Afterwards, both positron and electron are scattered by the nucleus.Fig. 5. QDCS for ionization of H2 by impact of positrons at 100 eVand electron energy E e = 19 eV.8. ConclusionsSummarizing the results presented in this communication, we have investigated the ionization of molecular hydrogen by the impact of positrons. The obtained quadruple differential cross-sections for the electron and the positron emerging in the same direction show three dominant structures. One is the well-known electron capture to the continuum peak. Another one is the Thomas mechanism. Finally, there is a minimum that might be interpreted as due to the so-called “saddle-point” ionization mechanism.But the main conclusion is that the study of the fully differential cross section might be hindered by a great number of difficulties, but the reward is that many different structures can be observed that otherwise are missed in double, single differential or total cross sections.中文译文正电原子在电离过程中碰撞的理论摘要我们回顾过去和现在正子原子在电离过程中碰撞理论的发展。

外文标题：Lost in translation? Culture, language and the role of the translator in international business外文作者：John Blenkinsopp and Maryam Shademan Pajouh文献出处: 《Critical Perspectives on International Business》 , 2018 , 6 (1) :38-52(如觉得年份太老，可改为近2年，毕竟很多毕业生都这样做)英文3189单词， 17020字符(字符就是印刷符)，中文5098汉字。

此文档是毕业设计外文翻译成品（含英文原文+中文翻译），无需调整复杂的格式！下载之后直接可用，方便快捷！本文价格不贵,也就几十块钱！一辈子也就一次的事！Lost in translation? Culture, language and the role of thetranslatorin international businessJohn Blenkinsopp and Maryam Shademan PajouhTeesside University Business School, UKAbstractPurpose Issues of language in international business have been the focus of a growing body of theoretical and empirical work, and this paper contributes to this literature, focusing specifically on issues of translation. The role of translator will vary depending on the language strategy adopted, with strategies linked to differing perspectives on language in international business – mechanical, cultural and political. We examine these perspectives through the lens of a specific problem for transnational communication –…untranslatable‟ words and concepts. Design/methodology/approach Interviews were conducted withprofessional linguists (translators and interpreters) to explore how they dealt with issues of untranslatable but cultural salient words in their day-to- day work with international businesses, using the problems of translating the Farsi word tarouf into English as a case in point.Findings The linguists agreed that tarouf was an untranslatable word, and described their strategies to deal with this problem. The commoneststrategy was avoidance, stemming from linguists‟ concern to maintain their professional standing with clients, a finding which reflects an emerging emphasis on the importance of context and relationships forunderstanding inter-cultural communication.Practical implications The study highlights the crucial role of the translator in international business, and draws attention to the potential for cross-cultural communication problems arising from mutual lack of awareness of culturally-salient but inherently untranslatable words or phrases.Social implications Effective inter-cultural communication is an issue ofgreat importance to wider society, and business has historically been thecommonest site of such communication. Our study highlights an issue of considerable importance for improving inter-cultural communications, contributing to a growing inter-disciplinary literature in this area.Originality/value Much of the research on language in internationalbusiness has focused on the emergence of English as a lingua franca, but the present study focuses on specific issues of translation and does so in an under-researched location, Iran. It draws attention to a problem of translation not widely discussed, and shows how important this issue can be for international business.Keywords: international business; interpreters; language; tarouf; translators; cross-cultural communicationIntroductionThe multinational corporation (MNC) is, by definition, a multilingual organisation (Fredriksson et al, 2006) and multilingual situations occurwith increasing regularity at various levels of the organisation (Charles and Marschan-Piekkari, 2002). Though issues of communication within MNCs have been a concern within the field of international business for an extended period, the specific issue of language was neglected until relatively recently (Janssens et al, 2004; Welch et al, 2005). A possible explanation is that international business practice has also been somewhat blind to this issue – though the practicalities of language barriers were widely recognised, the full implications of …talking a different language‟ were not. Welch and Welch suggest language is …a mental model, framing activity and behaviour‟ (2008: 341), and these framing effects can be visible even at the level of a single word.An example is offered by Wierzbicka‟s (2001) examination of the Polish word przykro. Usually translated as hurt, offended, sorry or sad, Wierzbicka suggests something is lost in translation, describing przyko as a …culturally salien Polish emotion. …That is not to say that speakers of English never experience the emotion associated in Polish with the word przykro; only that they do not think habitually about their experiences in these terms‟(Wierzbicka, 2001: 22). The Chinese word guanxi offers another obvious example of a word which is both culturally salient and yet inherently …untranslatable‟. Gaunxi has become widely known –discussed and researched to a point where there is a degree of awareness of the concept and its importance in international business.Linguistic imperialismMuch of the literature on the role of language in international business has focused on two particular features. The first is the decisions made by MNCs regarding language use, particularly around choices as to whether to adopt a corporate lingua franca (and if so, which language to adopt)and related issues of translation and interpretation. The second is thestudy of the growth of English as a lingua franca, through linguistic imperialism (Philipson, 1992).Though a complex notion, linguistic imperialism is usefully captured as the process by which speakers of onelanguage come to feel it necessary to use anoth er language, …to the point where they believe they can and should use only that foreign language when it comes to transactions dealing with the more advanced aspects of life‟ (Ansre, 1979, cited in Sliwe, 2008). Ansre is clearly describing a final outcome, and the process of linguistic imperialism is likely to be highly contested. Though the present article is focused on issues of translation in international business, the rise of English as a lingua franca through linguistic imperialism forms an important backdrop our study, and we will briefly explore this literature.Language barriers in international businessThese issues of translation can obviously be viewed as a language barrier for international business, but Harzing and Feely (2008) argue that the idea of …language barriers‟ has been rather under-defined. They propose a model of communication in which different components contribute to a vicious circle which creates the language barrier – failure to communicate effectively leads to uncertainty, anxiety and mistrust, which produces misattribution, conflict and cognitive distortion, to which the various parties respond by engaging in greater formality in communication, which is less effective...and the circle is completed. Their model focuses on the HQ- subsidiary relationship in MNCs, but the idea that communication problems arising from language differences might produce a vicious circle seems relevant to a range of settings within international business. Jameson argues that language …defines cultura l groups, as well as being the most frequently used symbolic systems through which culture is conveyed‟ (2007: 214), and as such it is core to cross-cultural communication in all settings. One of the key issues which led us to examine the issue of …untranslatable‟ words is that they are likely to lead to situations in which the failure to communicate effectively is either not recognised, or is recognised but baffling to the parties involved. Translation StudiesIn this section we want to examine some of the key ideas in the field of translation studies which might shed light on the present study, though it is useful to recall Nida‟s point that many translators will not draw upon theory in any conscious fashion:Instead of speaking of theories of translation, we should perhapsspeak more about various approaches to the task of translating, different orientations which provide helpful insight, and diverse ways of talking about how a message can be transferred from onelanguage to another.(Nida, 1991: 21).We can see that the translator has a key role to play in this process, but Pym (2006) notes that until recently the field of translation studies has paid relatively little attention to their role as mediators. It should be noted that although we have used translator as a generic term, it is more preciseto use this to refer to those who translate the written word. Translators of the spoken word are more commonly referred to as interpreters, and Pym(2006) suggests that the importance of the mediating role is more obviousand immediate for interpreters. Consistent with this, our findings suggest that the issue of untranslatable words presents more of a problem for interpreters thantranslators.An overview of TaroufTarouf (…tar-off’) is a Farsi word which describes a complex cultural construct. Three different English-Farsi dictionaries offer the following translations:- salutation, compliment, comity, chivalry- compliment, ceremony, offer, present- compliment(s), ceremony, offer, gift, flummery, courtesy, flattery,formality, good manners, soft tongue, honeyed phrases.Many of these words have only limited relation to each other, and this is because they can be seen as facets of tarouf, and the kinds of behaviours associated with it. Two examples illustrate tarouf more effectively than these definitions. The first is an Iranian joke:Many years ago, a young Persian woman became pregnant. Themonths passed and she kept getting bigger, finally nine months came but no baby came out. She kept getting bigger and b igger…but still no baby! Years went by until she became an old woman with a huge belly. Finally the doctors had a machine that could look into her belly and see what was going on in there. They looked inside and saw two men with beards saying to each other, ‘after you’, ‘no, after you’, ‘no please, after you’.A second example was told to us by an Iranian about his cousin, born inthe UK of Iranian parents, who made his first visit to Iran in his early 20s.He took a taxi back to the airport, and he and the driver chatted for the whole of the journey. When he got to the airport he asked the driver to tell him the fare, but the driver said there was no charge, it had been a pleasure to talk with him. My cousin didn’t know about tarouf, so he took this at fac e value, thanked him profusely and left!The driver, despite no doubt being aghast at this turn of events, let him go.This illustrates that tarouf is deeply culturally embedded –the driver could ill afford to offer a free fare for such a long journey, yet faced with a customer who did not recognise the conventions of tarouf he felt unable to step outside of them and demand the fare.MethodIn order to explore the idea of tarouf as an …untranslatable‟ word, we interviewed translators working in English and Farsi. We were unable to secure access to translators through agencies, who appeared concerned our approach was a ruse to gain access to translators without paying an agency fee. We therefore adopted a snowball sampling approach, going directly to individual translators based in Iran, and asking them torecommend other potential participants for us to contact. Clearly the study was premised on our claim that tarouf is untranslatable, so we initially asked all participants whether they agreed with that assertion. All confirmed that it was so, and we proceeded to explore the three empirical questions listed above via in-depth telephone interviews with 31individuals – 16 translators (5 men, 11 women) and 14 interpreters (12men, 2 women). Six of the interpreters were interviewed twice, and were also sentfollow-up e-mails seeking clarification of key points. It was not possible to record the interviews so we were unable to produce transcripts, however detailed notes were taken. The opportunity for follow-up interviews and e-mails provided a further rigour to the data gathering process. The question of the implications for international business communication was something upon which they could provide some insight, but we decided to compare their views to those of practising managers so after completing the interviews with the translators, we undertook telephone interviews with five managers (three Iranian, two British) working for MNCs in Iran. The data analysis approached adopted was somewhat simplistic, in t hat we treated the participants‟ response as reporting fact, rather than as texts for analysis.FindingsHow do you deal with the word tarouf in your work?Though the concept of tarouf permeates all Iranian writing and speech, the word itself will occur relatively infrequently in the kinds of business documents which translators handle. They were initially rather defensive when we asked them about the difficulties in translating tarouf. Once they understood we were not criticising their practice, but interested in how they dealt with the problem, they explained that where possible they would seek a word which captured as far as possible the particular element of tarouf which was relevant in that passage. (Note: if the translated passages were then subjected to back translation, often seen as the acid test of good translation, the second translator would almost certainly not translate any of these words as …tarouf‟). The challenge of translation posed by tarouf was not confined to the word itself. There are what might be called …tarouf phrases‟, expressions of politeness which serve a …phatic function‟ (Tietze, 2007), that is, a function in maintaining social relationships.DiscussionThe first is that translators have a clear view on how to handle the issue of untranslatable words. They generally choose either to find the closest approximation in the target language, or to ignore the word altogether. Only when neither option seems possible do they choose to raise the issue of the untranslatable nature of a word or phrase, and on such occasions they will provide an explanation of the cultural context in order to help the audience understand what the author/speaker is attempting to convey. The fact they engage in such explanations only when deemed unavoidableappears to arise from a concern about the impact of this on theirprofessional image.ConclusionThis study highlights the significance of …untranslatable‟ words in multi- cultural communications, and the crucial mediating role of the translator/interpreter in international business communication. Our participants‟description of their practice reflected elements of all three perspectives on language use – mechanical, cultural and political –described by Janssens et al (2004). Their core practice remained wedded to the mechanical perspective, as they attempted to render documents or speech between Farsi and English as accurately as possible. The…untranslatable‟ nature of tarouf tested this preferred way of working to its limits, but only in certain circumstances did they choose to provide their clients with the cultural perspective required to understand fully the nature of their business interactions. Their choices demonstrate the significant power dimension of their role, consistent with the political perspective, butwhereas Janssens et al (2004) highlight organisational power dynamics, in this instance it is the professional status and personal business concerns of the translator/interpreter which dominate. Their judgement as to whether or not to offer an explanation of tarouf is based upon their view of whether this will enhance or diminish their standing in the eyes of their clients (and by extension, whether or not this will lead to repeat business). This suggests a need for greater attention to the role of the translator, and in particular greater clarity from clients as to what they require. The irony of course is that when dealing with …untranslatable‟ words and conceptsthe clients do not know what they are missing, and are therefore unlikelyto see the need to specify their requirements.ReferencesBarner-Rasmussen, W, and Bjorkman, I. (2005), “Surmounting interunit barriers”, International Studies of Management and Organisation, Vol. 35 No.1, pp. 28-46. Bjerregaard, T, Lauring, J, and Klitmoll er, A. (2009). “A critical analysis of intercultural communication research in cross-cultural management: Introducing newer developments in anthropology”, Critical Perspectives on International Business , Vol. 5 No. 3, pp. 207-228.Charles, M. (2007), “Language matters in global communication”, Journal of Business Communication, Vol.44 No. 3, pp. 260-282.Charles, M, and Marschan-Piekkari, R. (2002), “Language training for enhanced horizontal communication: A challenge for MNCs”, Business Communication Quarterly, Vol. 65 No. 2, pp. 9-29.Dowling, P.J. and Welch, D.E. (2004), International Human Resource Management: Managing People in a Multinational Environment (4th Ed), London, Thomson Learning.Feely, A, J. and Harzing, A, W. (2003), “Language management i n multinational companies”, Journal of Cross Cultural Management, Vol. 10 No. 2, pp. 37-52.Fredriksson, R, Barner-Rasmussen, W. and Piekkari, R. (2006), “The multinational corporation as a multilingual organization: The notion of a common corporate langua ge”, Corporate Communications: An International Journal, Vol.11 No. 4, pp. 406-423.Harzing, A.W.K., and Feely, A.J. (2008), “The Language Barrier and its Implications for HQ-Subsidiary Relationships”, Cross Cultural Management: An International Journal, Vol. 15 No. 1, pp. 49-60. Jameson, D.A. (2007), “Reconceptualizing cultural identity and its role in intercultural business communication”, Journal of Business Communication, Vol. 44 No. 3, pp. 199-235.Janssens, M., Lambert, J., and Steyaert, C. (2004), “Developing languagestrategies for international companies: the contribution of translation studies”, Journal of World Business, Vol. 39 No. 4, pp. 414-430. Khomenei, A, R (1980), “Search and Find the East”, In Albert, H (ed). Tell the American People: Perspectives on the Iranian Revolution, Movement for a New Society, Philadelphia, pp. 204-210.Latifi, F. (1997), “Management Learning in National Context”, PhD thesis, Henley Management College.Lazarova, M., and Tarique, I. (2005), “Knowledge transfer upon repatriation”, Journal of World Business, Vol. 40 No. 4, pp. 361-373.Nida, E.A. (1991), “Theories of translation”, TTR: traduction, terminologie,rédaction, Vol. 4 No. 1, pp. 19-32.Phillipson, R. (1992), Linguistic Imperialism, Oxford, Oxford University Press. Pochhacker, F. (2006), “Interpreters and ideology: from …between‟ to…within‟”, Across Languages and Cultures, Vol. 7 No. 2, pp.191–207.Pym, A. (2006), “On the social and the cultural in Translation Studies”, in Pym, A., Shlesinger, M. and Jettmarová, Z. (Eds.), Sociocultural Aspects of Translating and Interpreting, Amsterdam and Philadelphia, Benjamins. Pym, A. (2008), “On Toury's laws of how translators translate”, in Pym, A.D., Shlesinger, M., and Simeoni, D. (Eds.), Beyond DescriptiveTranslation Studies: Investigations in Homage to Gideon Toury, Amsterdam and Philadelphia, Benjamins.Sliwa, M. (2008), “Understanding social change through post-colonialtheory: Reflections on linguistic imperialism and language spread in Poland”, Critical Perspective on International Business, Vol.4 No. 2/3, pp. 228-241. Tayeb, M. (2001), “Human Resource in Iran”, in Budwar, P.S. and Yaw, D. (Eds.) Human Resource Management in Developing Countries, London: Routledge, pp.121-134.Tietze, S. (2008), International Management and Language, London, Routledge.Tietze, S. (2007), “Language and international management emergent themes and new perspectives”, Bradford University School of Management Working Paper, No. 07/35.Tollefson, J.W. (1991), Planning Language, Planning Inequality, Language Policy in the Community, New York, Longman.Toury, G. (1995), Descriptive Translation Studies and beyond, Amsterdam and Philadelphia, Benjamins.Welch, D.E, and Welch, L.S. (2008), “The importance of language in international knowled ge transfer”, Management International Review, Vol.48 No. 3, pp. 339-360.Welch, D, Welch. L, and Piekkari, R. (2005), “Speaking in tongues: The impact of language in international management processes”, International Studies of Management and Organization, Vol. 35 No. 1, pp. 10-27. Wierzbicka, A. (2001), “A Culturally Salient Polish Emotion: Przykro ['Pshickro]”, International Journal of Group Tensions, Vol. 30 , pp. 3-27.在翻译中迷失？译者在国际商务中的文化、语言与角色约翰．布莱金索普和玛雅姆．塞得门．帕乔英国梯塞德大学商学院摘要目标：国际商务中有关的语言问题一直是越来越多的理论和实证性工作的焦点，本文促成了这些文献并专注于翻译问题。

电子碰撞电离氦原子的三重微分截面肖全志;贾昌春;章韦芳;陈姣姣【摘要】The triple differential cross sections (TDCS) for electron-impact ionization of helium (e,2e) reaction, using the method of partial wave expansions within the framework of first-order born approximation, were calculated at incident energies of 634.59, 604.59, 400, 250 and 150 Ev respectively. The results were compared with experimental measurements. It was obtained that the theoretical results using the full distorted wave bom approximation had a better agreement with the experimental results at incident energies of 604.59, 400 and 250 ev. For the case of incident energy of 634. 59 ev, better agreement with the experimental result was achieved if the 40 ev ejected electron was described by a Coulomb wave instead of the distorted wave. The trend, observed by the paper ( Ehrhatdt H, Hesselbacher K H, Jung K, et al. Collisional ionization of helium by 250 ev electrons; experiments with completely determined kinetics [ J]. J Phys B: At Opt Mol Phys, 1972, 5:2107-2116) , for changes of the relative intensity of the recoil peak and the angular position of the binary peak with ejected electron energy at a fixed scattering angle, has been confirmed.%在一级玻恩近似理论框架下,用分波法计算入射电子能量分别为634.59、604.59、400、250、150 eV的氦原子(e,2e)反应的三重微分截面(TDCS),并与实验结果进行比较.在入射电子能量为604.59、400、250 eV情况下,全扭曲波玻恩近似与实验较为符合；在入射电子能量为634.59 eV情况,其敲出电子能量40 eV条件下,考虑敲出电子库仑势的计算结果好于考虑敲出电子扭曲势的计算结果.在固定散射角情况下,Recoil峰的相对强度和Binary峰值位置随敲出电子能量变化的趋势,与文献(Ehrhatdt H,Hesselbacher K H,Jung K,et al.Collisional ionization of helium by 250 eV electrons:experiments with completely determinedkinetics[J].JPhysB:At Opt Mol Phys,1972,5:2107-2116)中提到的变化趋势一致.【期刊名称】《安徽大学学报（自然科学版）》【年(卷),期】2011(035)006【总页数】7页(P41-47)【关键词】三重微分截面;扭曲波;平面波;库仑波;Recoil峰;Binary峰【作者】肖全志;贾昌春;章韦芳;陈姣姣【作者单位】安徽大学物理与材料科学学院,安徽合肥230039;安徽大学物理与材料科学学院,安徽合肥230039;安徽大学物理与材料科学学院,安徽合肥230039;合肥师范学院物理与电子工程系,安徽合肥230061;安徽大学物理与材料科学学院,安徽合肥230039【正文语种】中文【中图分类】O561.5在多电子原子的(e，2e)反应理论研究中，氦原子无疑是最简单的原子靶.在单电子碰撞电离(e，2e)反应过程中，通过对三重微分截面(TDCS)的理论计算和实验测量的分析，可以研究原子、分子的结构和碰撞动力学机制.对于单电子碰撞电离，可以分为直接电离和同时电离激发过程.以氦原子靶为例，直接电离过程是指电子与氦原子碰撞后，把氦原子核外的一个电子电离，氦原子核外另一个电子仍然处于基态;同时电离激发过程是氦原子核外一个电子被电离后，核外另一个电子被激发到不同的激发态.该文讨论的是直接电离过程.由于电子与原子碰撞电离(e，2e)反应是一个多体问题，至今量子力学仍不能严格求解.所以在计算电子碰撞电离的三重微分截面时，就有多种不同的近似处理理论.例如，微扰理论、扭曲波玻恩近似理论［1］、非微扰理论、RMPS［2］(R-matrix with pseudostates)、TCC［3］(Time-dependent close-coupling)、CCC［4］(Convergent close-coupling)和ECS［5］(Exterior complex scaling)等理论方法.这些近似理论方法都能在一定程度上较好地解释实验结果.该文使用一级波恩近似理论，在共面非对称几何安排下，计算电子碰撞电离氦原子的三重微分截面.在Cherid等［6］的文章中，一级玻恩近似理论能较为准确地描述几千电子伏特的入射电子能量条件下的实验，其高级近似的影响小于10%.Tweed等［7］在计算高能入射电子碰撞电离靶原子的三重微分截面时发现，计算结果对靶原子初态和末态波函数较为敏感.Lahmam等［8］通过比较不同的一级近似理论，发现用库仑波描述敲出电子比用平面波描述好，但几种不同的计算模型都不能成功反映出实验结果的所有特征，特别是在Recoil峰上差别比较大.所以，作者在计算三重微分截面的过程中，考虑中低能的电子碰撞情况，对于靶初态波函数，不采用Hartree－Fock波函数［9］而是采用SilVerman等［10］的形式，对入射电子、散射电子和敲出电子分别使用不同的波函数来描述，所用的波函数分别为平面波(PW)、库仑波(CW)和扭曲波(DW)，计算结果分别与实验结果进行比较，从而揭示出在不同碰撞条件下各种不同相互作用的重要程度.作者研究结果表明，在固定散射角不变的情况下，Recoil峰的相对强度以及Binary峰值的位置随Ee变化的趋势，与文献［11］中提到的变化趋势一致.下面介绍计算电子碰撞电离氦原子TDCS的理论过程.在电子碰撞电离氦原子的(e，2e)反应中，考虑共面非对称几何安排，碰撞前靶原子氦处于基态.将入射电子标记为‘0’，该电子在碰撞前后动量分别为ki和kf;把靶原子氦中敲出的一个电子标为‘1’，其敲出后的动量为ke;剩余离子He+中的电子用‘2’标识.这样，(e，2e)反应碰撞前初态系统Hamiltonian表示为［1］:其中:ha(1，2)是氦原子的Hamiltonian，Tp(0)是入射电子的动能，Vi(0，1，2)是入射电子‘0’与靶原子中的两个电子以及靶原子核的库仑相互作用能.碰撞后末态系统Hamiltonian表示为［1］:其中:hion(2)是He+的Hamiltonian，Te(1)是从靶原子氦中被敲出的电子动能，Tp(0)是入射电子‘0’散射后的动能，Vf(0，1，2)是入射电子‘0’散射后与敲出电子‘1’、He+中的电子‘2’以及原子核的相互作用能.Uion(1，2)是敲出电子‘1’在He+的离子场中的势能.因为拥有(1)和(2)形式的Hamiltonian微分方程不能严格求解，所以要对(1)和(2)进行近似处理.把Vi(0，1，2)和Vf(0，1，2)作扭曲势处理后的Hamiltonian分别表示为:其中:Ui(0)、Uf(0)和ion(1)分别是对Vi(0，1，2)、Vf(0，1，2)和Uion(1，2)近似处理的形式.在计算过程中，对于入射电子和散射电子采用中性势和扭曲势［1］，其中扭曲势为:在共面不对称几何安排下，选用入射电子能量为634.59、604.59、400、250、150 eV等情况来计算电子碰撞电离氦原子的TDCS，并与实验结果进行比较.入射电子能量为634.59和604.59 eV的实验数据来自文献［12］，其他三种入射电子的实验数据来自文献［13］，这些数据都是绝对测量结果.在高度不对称条件下，实验测量都控制在较小的散射角和较低的敲出电子能量下进行，两个出射电子的交换效应可以忽略.由于入射电子与散射电子能量接近，所以在计算过程中选择相同的波函数描述入射电子与散射电子，同为扭曲波(DW)或者同为平面波(PW);敲出电子则选择库仑波(CW)或者扭曲波(DW)来描述.约定符号“DW－DW－CW”表示:入射电子用扭曲波(DW)描述、散射电子用扭曲波(DW)描述和敲出电子用库仑波(CW)描述，其他符号的含义可类推.入射电子能量用E0表示、敲出电子能量用Ee表示、散射电子能量用Ef表示以及散射角用θf表示.在计算中选择以靶为坐标原点，入射电子运动方向ki为参考方向，敲出电子的角度θe相对于入射电子运动方向ki在0～360°范围内变化;散射电子的散射角θf以顺时针为正，而敲出电子的出射角θe以逆时针为正.图1为较高能量入射电子碰撞电离氦原子的TDCS.图1中散射电子能量固定在Ef=570 eV，散射角为θf=4°，而入射电子能量E0和敲出电子能量Ee见图1a和b.图1a中全扭曲波(DW－DW－DW)形式的计算结果在Binary峰区域稍微低估了实验峰值强度，但所得的Binary峰值位置和波形与实验结果基本一致，DW－DW－CW计算结果与实验结果也相似，但是在Binary 峰位置，理论值高于实验结果，PW－PW－DW计算结果在Binary峰强度上与实验很相符，但是Binary峰值的位置与实验结果相比角度偏小.而与图1a相比，图1b的入射电子能量与敲出电子的能量都增大了，DW－DW－DW计算结果的Binary峰值的强度与实验结果相差较大，而PW－PW－CW计算结果与实验结果最为相符，虽然Binary峰值的强度和位置都有差别，但是这种差别不大.所以从图1可以看出，在较高的入射能量和较高的敲出能量情况下，用平面波描述入射电子与散射电子和用库仑波描述敲出电子比用全扭曲波描述它们所得的TDCS能较好地反应实验结果，这说明在入射电子能量为图1b所示的E0=634.59 eV情况下，扭曲效应不显著，并且扭曲波描述它们的结果与实验结果有一定的差距，用平面波就可以较好地描述入射电子与散射电子.对于散射电子的描述，由于散射电子能量较高，敲出电子与散射电子的相互作用影响不明显，图1b所示敲出电子能量较高Ee=40 eV情况下，把敲出电子与氦离子相互作用看成是敲出电子与一个带电粒子的库仑相互作用比用扭曲效应处理更接近真实情况.图2为较低能量入射电子碰撞电离氦原子的TDCS.图2与图1相比，入射电子能量逐渐降低，敲出电子能量也偏小，散射角都固定在θf=4°.对于入射电子能量在E0为400、250 eV的情况，如图2中的a、b、c、d所示，全扭曲波(DW－DW－DW)的计算结果比其他三种更符合实验数据，但其他三种计算结果在一定程度上也近似反映实验结果.这说明在这两种能量相对较高的条件下，考虑入射电子与氦原子的扭曲势和散射电子与氦离子的扭曲势，能够反映入射电子在碰撞前后的运动情况.而在入射电子能量E0=150 eV情况，如图2中的e、f所示，即使考虑到扭曲势，全扭曲波DW－DW－DW的计算结果在Binary峰上与实验结果差异很明显，这种明显的差异可能说明了一级玻恩近似已经不能满足要求，二级玻恩近似甚至更高级的玻恩近似需要被考虑.在图1、2中，对于各种不同的入射能量，全扭曲波DW－DW－DW的计算在Recoil峰上与实验结果比较相对更符合，优越于其他描述的计算结果，这说明了慢的敲出电子与剩余氦离子的相互作用在很大程度上影响Recoil峰［13］，所以如果使用更好的氦离子波函数以及敲出电子的波函数将会提高Recoil峰与实验数据的符合程度.在Ehrhardt等［11］文章中提到Recoil峰的相对强度随着θf和Ee的增加而降低，Binary峰值位置随着θf增加和Ee减小而增大.在该文的计算中，如图1、2所示，散射角都固定在θf=4°，Recoil峰的相对强度和Binary峰值位置随敲出电子能量变化的趋势，确实都与Ehrhardt等［11］所提到的变化趋势一致.在中等入射电子能量分别为604.59、400、250 eV的条件下，全扭曲波一级玻恩近似的理论计算能较好地描述实验结果;而当入射电子能量降低到150 eV的条件下，全扭曲波一级玻恩近似的计算与实验结果有较大的差异，二级玻恩近似甚至更高级的玻恩近似需要被考虑;但相比较而言，全扭曲波模型在描述Recoil峰方面明显要比其他三种模型优越一些.在固定散射角的情况下，获得了如Ehrhardt等［11］所提到Recoil峰的相对强度和Binary峰值位置随Ee的变化趋势.致谢:论文的研究工作中得到陈长进教授的大力支持，谨此鸣谢.【相关文献】［1］Chen Z J，Madison D H.Second－distorted wave calculation for electron-impact ionization of helium to He+(n=1 and n=2)［J］.J Phys B:At Mol Opt Phys，2005，38:4195－4209.［2］Bartschat K.The R-matrix with pseudo-states method:theory and applications to electron scattering and photoionization［J］.Comput Phys Commun，1998，114:168－182.［3］Pindzola M S，Obicheaux F R.Total ionization cross section for electron－hydrogen scattering using a time-dependent close－coupling method［J］.Phys Rev A，1996，54:2142－2145.［4］Bray I，Stelbovics A T.Calculation of the total ionization cross section and spin asymmetry in electron－hydrogen scattering from threshold to 500 ev［J］.Phys Rev Letts，1993，70:746－749.［5］Resigno T N，Baertschy M，Isaacs W A，et al.Collisional breakup in a quantum system of three charged particles［J］.Science，1999，24:2474－2479.［6］Cherid M，Duguet A，Lahman B A.An accurate investigation of the validity of the first Born approximation to describe high－energy(e，2e)cross sections at small and intermediate momentum transfer［J］.J Phys B:At Mol Opt Phys，1987，20:L187－L191. ［7］Tweed R J，Langlois J.Wave function effects in the calculation of cross sections for electron impact ionisation of helium at high energy［J］.J Phys B:At Mol Opt Phys，1987，20:5213－5232.［8］Lahman B A，Wellenstein H F，Cappello C D，et al.Coincidence electron impact ionisation of helium:absolute experimental cross sections and comparison with first-order theories［J］.J Phys B:At Mol Opt Phys，1984，17:3159－3172.［9］Byron J F W，Joachain C J.Correlation Effects in Atoms.I.Helium［J］.Phys Rev，1966，146:1－8.［10］Silverman J N，Platas O，Matsen F A.Simple configuration-interaction wave functions.I.two-electron ions－A numerical study［J］.J Chem phys，1960，32:1402－1406.［11］Ehrhatdt H，Hesselbacher K H，Jung K，et al.Collisional ionization of helium by 250 ev electrons:experiments with completely determined kinetics［J］.J Phys B:At Opt Mol Phys，1972，5:2107－2116.［12］Avaldi L，Camilloni R，Multari R，et al.Absolute measurement of ionization-excitation of helium at intermediate energies and their interpretation［J］.J Phys B:At Mol Opt Phys，1998，31:2981－2997.［13］Chlemmet P S，Srivastava M K，Rose T，et al.Electron impact ionization of helium at intermediate collision energies［J］.J Phys B:At Mol Opt Phys，1991，24:2719－2736.。