化学论文翻译 - 英文原文+汉语翻译

我们身边的化学的英文作文English:Chemistry is an integral part of our everyday lives, permeating everything from the air we breathe to the food we eat. It is the study of matter, its properties, composition, and the changes it undergoes. From the moment we wake up until we go to sleep, chemistry influences our actions and decisions. When we cook a meal, we engage in chemical reactions that transform raw ingredients into delicious dishes. The water we drink, essential for our survival, is a chemical compound with unique properties that sustain life. Even the simple act of lighting a match involves combustion, a chemical reaction that releases energy in the form of heat and light. Beyond the confines of our homes, chemistry plays a crucial role in industries such as pharmaceuticals, agriculture, and manufacturing, driving innovation and technological advancements. In medicine, chemists develop drugs to treat diseases, improving and saving countless lives. In agriculture, fertilizers and pesticides enhance crop yields, ensuring food security for millions. In manufacturing, chemical processes are used to produce an array of products, from plastics to textiles. Chemistry also intersects with environmental issues, as scientistsstrive to develop sustainable solutions to mitigate pollution and combat climate change. Understanding chemistry allows us to appreciate the world around us on a deeper level, empowering us to make informed choices that benefit both society and the environment.中文翻译：化学是我们日常生活中不可或缺的一部分，渗透到我们呼吸的空气和我们食用的食物中。

化学工业Chemical Industry1.化学工业的起源尽管化学品的使用可以追溯到古代文明时代，但我们所谓的现代化学工业的发展却是从近代才开始的。

可以认为它起源于工业革命其间，大约在1800年，并发展成为为其它工业部门提供化学原料的产业。

比如制肥皂所用的碱，棉布生产所用的漂白粉，玻璃制造业所用的硅及Na2CO3。

我们会注意到所有这些都是无机物。

有机化学工业的开始是在十九世纪六十年代以William Henry Perkin 发现第一种合成染料—苯胺紫并加以开发利用为标志的。

20世纪初，德国花费大量资金用于实用化学方面的重点研究，到1914年，德国的化学工业在世界化学产品市场上占有75%的份额。

这要归因于新染料的发现以及接触法制硫酸和氨的哈伯生产工艺的发展。

而后者需要较大的技术突破使得化学反应第一次可以在非常高的压力条件下进行。

这方面所取得的成绩对德国很有帮助。

特别是由于1914年第一次世界大战的爆发，对以氮为基础的化合物的需求飞速增长。

这种深刻的改变一直持续到第一次世界大战结束至第二次世界大战开始这段时间(1918-1939年)。

1940年以来，化学工业一直以引人注目的速度飞速发展。

尽管这种发展的速度近年来已大大减慢。

化学工业的发展由于1950年以来石油化学领域的研究和开发大部分在有机化学方面取得。

石油化工在60年代和70年代的迅猛发展主要是由于人们对于合成高聚物如聚乙烯、聚丙烯、尼龙、聚脂和环氧树脂的需求巨大增加。

今天的化学工业已经是制造业中有着许多分支的部门，并且在制造业中起着核心的作用。

它生产了数千种不同的化学产品，而人们通常只接触到终端产品或消费品。

这些产品被购买是因为他们具有某些性质适合人们的一些特别的用途，例如，用于盆的不粘涂层或一种杀虫剂。

这些化学产品归根到底是由于它们能产生的作用而被购买的。

2.化学工业的定义在本世纪初，要定义什么是化学工业是不太困难的，因为那时所生产的化学品是很有限的，而且是非常清楚的化学品，例如，烧碱，硫酸。

Foreign material：Chemical Industry1.Origins of the Chemical IndustryAlthough the use of chemicals dates back to the ancient civilizations, the evolution of what we know as the modern chemical industry started much more recently. It may be considered to have begun during the Industrial Revolution, about 1800, and developed to provide chemicals roe use by other industries. Examples are alkali for soapmaking, bleaching powder for cotton, and silica and sodium carbonate for glassmaking. It will be noted that these are all inorganic chemicals. The organic chemicals industry started in the 1860s with the exploitation of William Henry Perkin’s discovery if the first synthetic dyestuff—mauve. At the start of the twentieth century the emphasis on research on the applied aspects of chemistry in Germany had paid off handsomely, and by 1914 had resulted in the German chemical industry having 75% of the world market in chemicals. This was based on the discovery of new dyestuffs plus the development of both the contact process for sulphuric acid and the Haber process for ammonia. The later required a major technological breakthrough that of being able to carry out chemical reactions under conditions of very high pressure for the first time. The experience gained with this was to stand Germany in good stead, particularly with the rapidly increased demand for nitrogen-based compounds (ammonium salts for fertilizers and nitric acid for explosives manufacture) with the outbreak of world warⅠin 1914. This initiated profound changes which continued during the inter-war years (1918-1939).Since 1940 the chemical industry has grown at a remarkable rate, although this has slowed significantly in recent years. The lion’s share of this growth has been in the organic chemicals sector due to the development and growth of the petrochemicals area since 1950s. The explosives growth in petrochemicals in the 1960s and 1970s was largely due to the enormous increase in demand for synthetic polymers such as polyethylene, polypropylene, nylon, polyesters and epoxy resins.The chemical industry today is a very diverse sector of manufacturing industry, within which it plays a central role. It makes thousands of different chemicals whichthe general public only usually encounter as end or consumer products. These products are purchased because they have the required properties which make them suitable for some particular application, e.g. a non-stick coating for pans or a weedkiller. Thus chemicals are ultimately sold for the effects that they produce.2. Definition of the Chemical IndustryAt the turn of the century there would have been little difficulty in defining what constituted the chemical industry since only a very limited range of products was manufactured and these were clearly chemicals, e.g., alkali, sulphuric acid. At present, however, many intermediates to products produced, from raw materials like crude oil through (in some cases) many intermediates to products which may be used directly as consumer goods, or readily converted into them. The difficulty cones in deciding at which point in this sequence the particular operation ceases to be part of the chemical industry’s sphere of activities. To consider a specific example to illustrate this dilemma, emulsion paints may contain poly (vinyl chloride) / poly (vinyl acetate). Clearly, synthesis of vinyl chloride (or acetate) and its polymerization are chemical activities. However, if formulation and mixing of the paint, including the polymer, is carried out by a branch of the multinational chemical company which manufactured the ingredients, is this still part of the chemical industry of does it mow belong in the decorating industry?It is therefore apparent that, because of its diversity of operations and close links in many areas with other industries, there is no simple definition of the chemical industry. Instead each official body which collects and publishes statistics on manufacturing industry will have its definition as to which operations are classified as the chemical industry. It is important to bear this in mind when comparing statistical information which is derived from several sources.3. The Need for Chemical IndustryThe chemical industry is concerned with converting raw materials, such as crude oil, firstly into chemical intermediates and then into a tremendous variety of other chemicals. These are then used to produce consumer products, which make our livesmore comfortable or, in some cases such as pharmaceutical produces, help to maintain our well-being or even life itself. At each stage of these operations value is added to the produce and provided this added exceeds the raw material plus processing costs then a profit will be made on the operation. It is the aim of chemical industry to achieve this.It may seem strange in textbook this one to pose the question “do we need a chemical industry?” However trying to answer this question will provide(ⅰ) an indication of the range of the chemical industry’s activities, (ⅱ) its influence on our lives in everyday terms, and (ⅲ) how great is society’s need for a chemical industry. Our approach in answering the question will be to consider the industry’s co ntribution to meeting and satisfying our major needs. What are these? Clearly food (and drink) and health are paramount. Other which we shall consider in their turn are clothing and (briefly) shelter, leisure and transport.(1)Food. The chemical industry makes a major contribution to food production in at least three ways. Firstly, by making available large quantities of artificial fertilizers which are used to replace the elements (mainly nitrogen, phosphorus and potassium) which are removed as nutrients by the growing crops during modern intensive farming. Secondly, by manufacturing crop protection chemicals, i.e., pesticides, which markedly reduce the proportion of the crops consumed by pests. Thirdly, by producing veterinary products which protect livestock from disease or cure their infections.(2)Health. We are all aware of the major contribution which the pharmaceutical sector of the industry has made to help keep us all healthy, e.g. by curing bacterial infections with antibiotics, and even extending life itself, e.g. ß–blockers to lower blood pressure.(3)Clothing. The improvement in properties of modern synthetic fibers over the traditional clothing materials (e.g. cotton and wool) has been quite remarkable. Thus shirts, dresses and suits made from polyesters like Terylene and polyamides like Nylon are crease-resistant, machine-washable, and drip-dry or non-iron. They are also cheaper than natural materials.Parallel developments in the discovery of modern synthetic dyes and the technology to “bond” th em to the fiber has resulted in a tremendous increase in the variety of colors available to the fashion designer. Indeed they now span almost every color and hue of the visible spectrum. Indeed if a suitable shade is not available, structural modification of an existing dye to achieve this canreadily be carried out, provided there is a satisfactory market for the product.Other major advances in this sphere have been in color-fastness, i.e., resistance to the dye being washed out when the garment is cleaned.(4)Shelter, leisure and transport. In terms of shelter the contribution of modern synthetic polymers has been substantial. Plastics are tending to replace traditional building materials like wood because they are lighter, maintenance-free (i.e. they are resistant to weathering and do not need painting). Other polymers, e.g. urea-formaldehyde and polyurethanes, are important insulating materials f or reducing heat losses and hence reducing energy usage.Plastics and polymers have made a considerable impact on leisure activities with applications ranging from all-weather artificial surfaces for athletic tracks, football pitches and tennis courts to nylon strings for racquets and items like golf balls and footballs made entirely from synthetic materials.Like wise the chemical industry’s contribution to transport over the years has led to major improvements. Thus development of improved additives like anti-oxidants and viscosity index improves for engine oil has enabled routine servicing intervals to increase from 3000 to 6000 to 12000 miles. Research and development work has also resulted in improved lubricating oils and greases, and better brake fluids. Yet again the contribution of polymers and plastics has been very striking with the proportion of the total automobile derived from these materials—dashboard, steering wheel, seat padding and covering etc.—now exceeding 40%.So it is quite apparent even from a brief look at the chemical industry’s contribution to meeting our major needs that life in the world would be very different without the products of the industry. Indeed the level of a country’s development may be judged by the production level and sophistication of its chemical industry4. Research and Development (R&D) in Chemical IndustriesOne of the main reasons for the rapid growth of the chemical industry in the developed world has been its great commitment to, and investment in research and development (R&D). A typical figure is 5% of sales income, with this figure being almost doubled for the most research intensive sector, pharmaceuticals. It is important to emphasize that we are quoting percentages here not of profits but of sales income, i.e. the total money received, which has to pay for raw materials, overheads, staff salaries, etc. as well. In the past this tremendous investment has paid off well, leading to many useful and valuable products being introduced to the market. Examplesinclude synthetic polymers like nylons and polyesters, and drugs and pesticides. Although the number of new products introduced to the market has declined significantly in recent years, and in times of recession the research department is usually one of the first to suffer cutbacks, the commitment to R&D remains at a very high level.The chemical industry is a very high technology industry which takes full advantage of the latest advances in electronics and engineering. Computers are very widely used for all sorts of applications, from automatic control of chemical plants, to molecular modeling of structures of new compounds, to the control of analytical instruments in the laboratory.Individual manufacturing plants have capacities ranging from just a few tones per year in the fine chemicals area to the real giants in the fertilizer and petrochemical sectors which range up to 500,000 tonnes. The latter requires enormous capital investment, since a single plant of this size can now cost $520 million! This, coupled with the widespread use of automatic control equipment, helps to explain why the chemical industry is capital-rather than labor-intensive.The major chemical companies are truly multinational and operate their sales and marketing activities in most of the countries of the world, and they also have manufacturing units in a number of countries. This international outlook for operations, or globalization, is a growing trend within the chemical industry, with companies expanding their activities either by erecting manufacturing units in other countries or by taking over companies which are already operating there.化学工业1.化学工业的起源尽管化学品的使用可以追溯到古代文明时代，我们所谓的现代化学工业的发展却是非常近代（才开始的）。

01. THE ELEMENTS AND THE PERIODIC TABLE 01元素和元素周期表。

The number of protons in the nucleus of an atom is referred to as the atomic number, or proton number, Z. The number of electrons in an electrically neutral atom is also equal to the atomic number, Z. The total mass of an atom is determined very nearly by the total number of protons and neutrons in its nucleus. This total is called the mass number, A. The number of neutrons in an atom, the neutron number, is given by the quantity A-Z.原子核中的质子数的原子称为原子序数，或质子数，卓电子数的电中性的原子也等于原子序数Z，总质量的原子是非常接近的总数量的质子和中子在原子核。

这被称为质量数，这个数的原子中的中子，中子数，给出了所有的数量The term element refers to, a pure substance with atoms all of a single kind. To the chemist the "kind" of atom is specified by its atomic number, since this is the property that determines its chemical behavior. At present all the atoms from Z = 1 to Z = 107 are known; there are 107 chemical elements. Each chemical element has been given a name and a distinctive symbol. For most elements the symbol is simply the abbreviated form of the English name consisting of one or two letters, for example:术语元素是指，一个纯粹的物质与一个单一的一种原子。

化学化工类外文翻译原文Original Text:Chapter 1 Introduction1.1 BackgroundNuclear energy has been providing a significant share of the world’s electricity for more than half a century. Currently, nuclear power plants generate approximately 10% of the world’s electricity supply, with this figure increasing to over 30% in some countries such as France [1]. However, for nuclear energy to continue to be an important source of electricity in the future, the safe and efficient operation of nuclear power plants must be ensured. A key component of ensuring safe and efficient operation is the availability of inspection techniques that can detect defects, assess their severity, and monitor their growth over time.The presence of defects in materials used in nuclear power plants can arise from a number of sources including fabrication, welding, and service exposure. Defects can manifest themselves as a variety of features such as cracks, voids, inclusions, and inhomogeneities. Defects can be classified based on their size, shape, and orientation, with some defectsbeing more critical to the performance and safety of a component than others. For example, surface-breaking transverse cracks in pressure vessel components can be particularly critical since they can rapidly propagate under service loading and can lead to catastrophic failure if not detected and remedied in a timely manner [2].Inspection techniques used to detect and monitor defects in nuclear power plant components are continually evolving. Inspection methods have traditionally included visual examination, ultrasonics, radiography, and eddy current testing [3]. These techniques have proven reliable and effective, but have limitations such as the inability to inspect certain materials and geometries. In addition, advances in materials science and technology have led to the development of new materials with different physical and chemical properties that may not be well-suited to traditional inspection techniques. Therefore, there is a need to develop and optimize inspection techniques that are capable of detecting andmonitoring defects in advanced materials and structures.1.2 Objectives and ScopeThe primary objective of this chapter is to provide an overview of the different types of inspection techniques that are currently used in the nuclearpower industry for detecting, characterizing, and monitoring defects in materials and components. The chapter will discuss the limitations of current inspection techniques and the challenges associated with the inspection of advanced materials and structures. The chapter will also highlight recent developments in inspection techniques including the use of advanced sensors, imaging, and data analysis techniques.The scope of the chapter will cover a range of inspection techniques used in the nuclear power industry including visual examination, ultrasonics, radiography, eddy current testing, and other techniques such as thermography and acoustic emission testing. The chapter will focus on the application of these techniques to welds, pressure vessels, steam generators, and reactor components. The chapter will also briefly discuss the use of inspection techniques for other applications such as monitoring corrosion and degradation of materials.1.3 Organization of the ChapterThe remainder of this chapter is organized as follows. Section 2 provides an overview of visual examination and its application to the inspection of nuclear power plant components. Section 3 describes ultrasonic inspection techniques and their use in detecting and characterizing defects in materials and components.Section 4 discusses radiography and its use forimaging defects in materials. Section 5 covers eddy current testing and its application to the detectionof surface and subsurface defects. Section 6 provides an overview of other non-destructive evaluation techniques such as thermography and acoustic emission testing. Section 7 summarizes recent developments in inspection techniques including the use of advanced sensors and imaging techniques. Section 8 concludesthe chapter with a discussion of challenges and future directions in inspection technology for nuclear power plant components.中文翻译：第一章绪论1.1 背景核能已经为全球电力供应提供了半个多世纪的重要部分。

Foreign material：Chemical Industry1.Origins of the Chemical IndustryAlthough the use of chemicals dates back to the ancient civilizations, the evolution of what we know as the modern chemical industry started much more recently. It may be considered to have begun during the Industrial Revolution, about 1800, and developed to provide chemicals roe use by other industries. Examples are alkali for soapmaking, bleaching powder for cotton, and silica and sodium carbonate for glassmaking. It will be noted that these are all inorganic chemicals. The organic chemicals industry started in the 1860s with the exploitation of William Henry Perkin’s discovery if the first synthetic dyestuff—mauve. At the start of the twentieth century the emphasis on research on the applied aspects of chemistry in Germany had paid off handsomely, and by 1914 had resulted in the German chemical industry having 75% of the world market in chemicals. This was based on the discovery of new dyestuffs plus the development of both the contact process for sulphuric acid and the Haber process for ammonia. The later required a major technological breakthrough that of being able to carry out chemical reactions under conditions of very high pressure for the first time. The experience gained with this was to stand Germany in good stead, particularly with the rapidly increased demand for nitrogen-based compounds (ammonium salts for fertilizers and nitric acid for explosives manufacture) with the outbreak of world warⅠin 1914. This initiated profound changes which continued during the inter-war years (1918-1939).Since 1940 the chemical industry has grown at a remarkable rate, although this has slowed significantly in recent years. The lion’s share of this growth has been in the organic chemicals sector due to the development and growth of the petrochemicals area since 1950s. The explosives growth in petrochemicals in the 1960s and 1970s was largely due to the enormous increase in demand for synthetic polymers such as polyethylene, polypropylene, nylon, polyesters and epoxy resins.The chemical industry today is a very diverse sector of manufacturing industry, within which it plays a central role. It makes thousands of different chemicals whichthe general public only usually encounter as end or consumer products. These products are purchased because they have the required properties which make them suitable for some particular application, e.g. a non-stick coating for pans or a weedkiller. Thus chemicals are ultimately sold for the effects that they produce.2. Definition of the Chemical IndustryAt the turn of the century there would have been little difficulty in defining what constituted the chemical industry since only a very limited range of products was manufactured and these were clearly chemicals, e.g., alkali, sulphuric acid. At present, however, many intermediates to products produced, from raw materials like crude oil through (in some cases) many intermediates to products which may be used directly as consumer goods, or readily converted into them. The difficulty cones in deciding at which point in this sequence the particular operation ceases to be part of the chemical industry’s sphere of activities. To consider a specific example to illustrate this dilemma, emulsion paints may contain poly (vinyl chloride) / poly (vinyl acetate). Clearly, synthesis of vinyl chloride (or acetate) and its polymerization are chemical activities. However, if formulation and mixing of the paint, including the polymer, is carried out by a branch of the multinational chemical company which manufactured the ingredients, is this still part of the chemical industry of does it mow belong in the decorating industry?It is therefore apparent that, because of its diversity of operations and close links in many areas with other industries, there is no simple definition of the chemical industry. Instead each official body which collects and publishes statistics on manufacturing industry will have its definition as to which operations are classified as the chemical industry. It is important to bear this in mind when comparing statistical information which is derived from several sources.3. The Need for Chemical IndustryThe chemical industry is concerned with converting raw materials, such as crude oil, firstly into chemical intermediates and then into a tremendous variety of other chemicals. These are then used to produce consumer products, which make our livesmore comfortable or, in some cases such as pharmaceutical produces, help to maintain our well-being or even life itself. At each stage of these operations value is added to the produce and provided this added exceeds the raw material plus processing costs then a profit will be made on the operation. It is the aim of chemical industry to achieve this.It may seem strange in textbook this one to pose the question “do we need a chemical industry?” However trying to answer this question will provide(ⅰ) an indication of the range of the chemical industry’s activities, (ⅱ) its influence on our lives in everyday terms, and (ⅲ) how great is society’s need for a chemical industry. Our approach in answering the question will be to consider the industry’s co ntribution to meeting and satisfying our major needs. What are these? Clearly food (and drink) and health are paramount. Other which we shall consider in their turn are clothing and (briefly) shelter, leisure and transport.(1)Food. The chemical industry makes a major contribution to food production in at least three ways. Firstly, by making available large quantities of artificial fertilizers which are used to replace the elements (mainly nitrogen, phosphorus and potassium) which are removed as nutrients by the growing crops during modern intensive farming. Secondly, by manufacturing crop protection chemicals, i.e., pesticides, which markedly reduce the proportion of the crops consumed by pests. Thirdly, by producing veterinary products which protect livestock from disease or cure their infections.(2)Health. We are all aware of the major contribution which the pharmaceutical sector of the industry has made to help keep us all healthy, e.g. by curing bacterial infections with antibiotics, and even extending life itself, e.g. ß–blockers to lower blood pressure.(3)Clothing. The improvement in properties of modern synthetic fibers over the traditional clothing materials (e.g. cotton and wool) has been quite remarkable. Thus shirts, dresses and suits made from polyesters like Terylene and polyamides like Nylon are crease-resistant, machine-washable, and drip-dry or non-iron. They are also cheaper than natural materials.Parallel developments in the discovery of modern synthetic dyes and the technology to “bond” th em to the fiber has resulted in a tremendous increase in the variety of colors available to the fashion designer. Indeed they now span almost every color and hue of the visible spectrum. Indeed if a suitable shade is not available, structural modification of an existing dye to achieve this canreadily be carried out, provided there is a satisfactory market for the product.Other major advances in this sphere have been in color-fastness, i.e., resistance to the dye being washed out when the garment is cleaned.(4)Shelter, leisure and transport. In terms of shelter the contribution of modern synthetic polymers has been substantial. Plastics are tending to replace traditional building materials like wood because they are lighter, maintenance-free (i.e. they are resistant to weathering and do not need painting). Other polymers, e.g. urea-formaldehyde and polyurethanes, are important insulating materials f or reducing heat losses and hence reducing energy usage.Plastics and polymers have made a considerable impact on leisure activities with applications ranging from all-weather artificial surfaces for athletic tracks, football pitches and tennis courts to nylon strings for racquets and items like golf balls and footballs made entirely from synthetic materials.Like wise the chemical industry’s contribution to transport over the years has led to major improvements. Thus development of improved additives like anti-oxidants and viscosity index improves for engine oil has enabled routine servicing intervals to increase from 3000 to 6000 to 12000 miles. Research and development work has also resulted in improved lubricating oils and greases, and better brake fluids. Yet again the contribution of polymers and plastics has been very striking with the proportion of the total automobile derived from these materials—dashboard, steering wheel, seat padding and covering etc.—now exceeding 40%.So it is quite apparent even from a brief look at the chemical industry’s contribution to meeting our major needs that life in the world would be very different without the products of the industry. Indeed the level of a country’s development may be judged by the production level and sophistication of its chemical industry4. Research and Development (R&D) in Chemical IndustriesOne of the main reasons for the rapid growth of the chemical industry in the developed world has been its great commitment to, and investment in research and development (R&D). A typical figure is 5% of sales income, with this figure being almost doubled for the most research intensive sector, pharmaceuticals. It is important to emphasize that we are quoting percentages here not of profits but of sales income, i.e. the total money received, which has to pay for raw materials, overheads, staff salaries, etc. as well. In the past this tremendous investment has paid off well, leading to many useful and valuable products being introduced to the market. Examplesinclude synthetic polymers like nylons and polyesters, and drugs and pesticides. Although the number of new products introduced to the market has declined significantly in recent years, and in times of recession the research department is usually one of the first to suffer cutbacks, the commitment to R&D remains at a very high level.The chemical industry is a very high technology industry which takes full advantage of the latest advances in electronics and engineering. Computers are very widely used for all sorts of applications, from automatic control of chemical plants, to molecular modeling of structures of new compounds, to the control of analytical instruments in the laboratory.Individual manufacturing plants have capacities ranging from just a few tones per year in the fine chemicals area to the real giants in the fertilizer and petrochemical sectors which range up to 500,000 tonnes. The latter requires enormous capital investment, since a single plant of this size can now cost $520 million! This, coupled with the widespread use of automatic control equipment, helps to explain why the chemical industry is capital-rather than labor-intensive.The major chemical companies are truly multinational and operate their sales and marketing activities in most of the countries of the world, and they also have manufacturing units in a number of countries. This international outlook for operations, or globalization, is a growing trend within the chemical industry, with companies expanding their activities either by erecting manufacturing units in other countries or by taking over companies which are already operating there.化学工业1.化学工业的起源尽管化学品的使用可以追溯到古代文明时代，我们所谓的现代化学工业的发展却是非常近代（才开始的）。

多样性的进化和跳增Polo样激酶-1抑制剂Polo样激酶〔Plk1〕，是丝氨酸/苏氨酸酶中的一种，它是抗癌药物的发展历程中很具吸引力的样品，因为它涉及到细胞周期进程的规定及胞质分裂。

这个激酶为开发Plk1抑制剂提供了两种途径：n端催化域〔NCD〕和polo-box域〔PBD〕。

对于这两个域，一些天然产物被确定为Plk1抑制剂，一些则被模拟ATP和磷酸化肽段开发成P1k1抑制剂，天然产物分别为NCD和PBD所约束。

本文不仅评论Plk1抑制剂的这两个途径的发展，还讨论了以多样性进化及药物开发的跳增过程中使用Plk1抑制剂为例，以及它们是如何影响药物设计和药效团模型的。

1.介绍化学的空间是巨大的，据估计可能存在的药物如分子的数量就超过1060,这与目前已知的107形成了鲜明的比照。

对于药物的发现，部署这么一个多样性的化学库是非常重要的。

虽然天然产物，与特定分子的化合物和生物体产生不同的结构特点，可能只占化学空间里的很小一部分，通过自然选择，他们拥有一个独特的、巨大的化学多样性。

个体天然产物及其结构成员有多个最正确的生物活性，因此最有可能绑定多个目标，然后影响它们的功能。

因此，天然产物是目前最富有的新颖的化合物来源，在药物发现中发挥了重要作用，尤其是抗生素和癌症治疗领域的发展。

2.Plk1抑制剂的进展2.1 蛋白激酶和基于ATP抑制剂多样性跳增的设计蛋白激酶，拥有超过500个成员的的最大的蛋白家族之一，通过添加丝氨酸和苏氨酸的磷酸基团或酪氨酸残基来修饰其他蛋白质。

磷酸化是许多疾病的一个必要步骤，包括癌症，炎症，糖尿病。

因此，药物学家已经对蛋白激酶产生了极大的兴趣，已经作为治疗目标的药物靶点的第二大组。

自2001年起许多激酶抑制剂已经被批准用于治疗癌症和炎症。

所有的激酶在ATP反跳的时候都有一个催化结合域的结合。

ATP是一种核苷酸磷酸在细胞里作为辅酶。

设计激酶抑制剂的策略是模仿ATP来适合催化和抑制目标。

英语原文Highly Efficient One-Pot Three-Component Mannich Reaction in Water Catalyzed by Heteropoly AcidsAbstractHeteropoly acids efficiently catalyzed the one-pot, three-component Carrying out organic reactions in water has become highly desirable in recent years to meet environmental considerations.1The use of water as a sole medium for organic reactions would greatly contribute to the development of environmentally friendly processes. Indeed, industry prefers to use water as a solvent rather than toxic organic solvents. In this context, in recent years, much attention has been focused on Lewis acid catalyzed organic reactions in water.Heteropoly acids (HPAs) are environmentally benign and economically feasible solid catalysts that offer several advantages.2Therefore, organic reactions that exploit heteropoly acid catalysts in water could prove ideal for industrial synthetic organic chemistry applications, provided that the catalysts show high catalytic activity in water.Mannich reactions are among the most important carbon−carbon bondforming reactions in organic synthesis.3They provide β−amino carbonyl compounds, which are important synthetic intermediates for various pharmaceuticals and natural products.4The increasing popularity of the Mannich reaction has been fueled by the ubiquitous nature of nitrogen-containing compounds in drugs and natural products.5However, the classical Mannich reaction is plagued by a number of serious disadvantages and has limited applications. Therefore, numerous modern versions of the Mannich reaction have been developed to overcome the drawbacks of the classical method. In general, the improved methodology relies on the two-component system using preformed electrophiles, such as imines, and stable nucleophiles, such as enolates, enol ethers, and enamines.6But the preferable route is the use of a one-pot three-component strategy that allows for a wide range of structural variations. In this context, recent developments of asymmetric synthesis, using a three-component protocol, have made the Mannich reaction very valuable.7 However, despite the diverse synthetic routes so far developed for the asymmetric Mannich reaction, only a few one-pot procedures on the use of unmodified aldehydes or ketones in water have been reported in the literature. Furthermore, most of the reported Mannich reactions in water have been carried out in the presence of surfactants such as SDS. Unfortunately, normal-phase separation is difficult during workup due to the formation of emulsions because of the SDS.There is increasing interest in developing environmentally benign reactions and atom-economic catalytic processes that employ unmodified ketones, amines, and aldehydes for Mannich-type reaction in recent years. In continuation of our studies on the new variants, of one-pot, three-component Mannich-type reactions for aminoalkylation of aldehydes with different nucleophiles,9and our ongoing green organic chemistry program that uses water as a reaction medium, performs organic transformations under solvent-free conditions,10 herein we describe a mild, convenient, and simple procedure for effecting the one-pot, three-component reaction of an aldehyde, an amine, and a ketone for the preparation of β-amino carbonyl compounds in water using a heteropoly acid catalyst.Initially, the three-component Mannich reaction of 4-chlorobenzaldehyde (3.0 mmol), aniline (3.1 mmol), and the cyclohexanone (5 mmol) was examined (Scheme 1).Scheme 1. Direct Mannich Reaction Catalyzed by Heteropoly Acids in Different SolventsAs a preliminary study, several Lewis acids and solvents were screened in the model reaction. The results of extensive Lewis acid and solvent screening and optimization are shown in a table in the Supporting Information.Heteropolyacids (HPAs) catalyze Mannich reactions in organic solvents such as acetonitrile, 1,2-dichloroethane, methanol, ethanol, toluene and mixtures of toluene/water and gave the desired products in low yield with the foramtion of aldol side products. Among the screened solvent systems, water was the solvent of choice, since in this solvent the Mannich-type reactions proceeded smoothly and afforded the desired adducts in high yields at room temperature. Consequently, we conclude that the HPAs are much more reactive in water than in other organic solvents. At room temperature, the Mannich reaction proceeded to completion affording the Mannich adduct in good to excellent yield and relatively good diastereoselectivity. Addition of surfactants such as sodium dodecyl sulfate (SDS) or cetyltrimethylammonium bromide (CTAB) was not effective, and they did not improve diastereoselectivity. The reaction in pure water without using any catalyst gave a low yield of the product. Furthermore, we were excited to find that only 0.12 mol % of the catalyst gave good yields at room temperature. In the some cases, even 0.06 mol % of HPA was sufficient for the completion of the reaction. Furthermore, simple workup in water opened the route for an entirely green highly efficient one-pot Mannich reaction in water. In addition, H3PMo12O40has been compared with H3PW12O40, and we found the same results for both heteropoly acids in this reaction in water.Encouraged by the remarkable results obtained with the above reaction conditions, and in order to show the generality and scope of this new protocol, we used various aldehydes and amines and the results. T able 2 clearly demonstrates that HPAs are excellent catalysts for Mannich reactions in water. Thus, a variety of aromatic aldehydes, including electron-withdrawing and electron-donating groups, were tested using our new method in water in the presence of H3PW12O40or H3PMo12O40. The results are shown in T able 2. Generally, excellent yields of α-amino ketones were obtained for a variety of aldehydes including those bearing an electron-withdrawing group. Furthermore, several electron-rich aromatic aldehydes led to the desired products in good yield. However, under the same reaction conditions aliphatic aldehydes, such as isobutyaldehyde, gave a mixture, due to enamine formation; the desired product was obtained in low yield (Table 2, entry 22). The scope of our method was extended to other amines. In the case of amines having an electron-donating group, such as 4-isopropylaniline, the corresponding amino ketones were obtained in good yields. Furthermore, amines with electron-withdrawing groups, such as 4-chloroaniline and 3,4-dichloroaniline, gave the desired product in good yields.The high yield, simple reaction protocol, and originality of this novel process prompted us to use other ketones under these conditions (Table 1). Thus, the three-component coupling reactions were carried out with acyclic ketones such as 2-butanone and acetophenone. The expected products were obtained in moderate yields under these conditions. Acyclic ketones were less reactive than cyclohexanone and needed much more catalyst to afford the desiredproducts (T able 1). Table 1. HPA-Catalyzed Three-Component MannichReaction a Table 2. One-Pot, Three-Component Direct MannichReaction aaldehydes by the use of proline, HBF4, and dibutyltin dimethoxide.Scheme 2. Aldole and Mannich Reaction in Water翻译稿杂多酸高效催化三组分共混曼尼希反应Najmodin艾则孜，LallehT orkiyan，穆罕默德R •赛迪*谢里夫理工大学化学系，PO 11465-9516箱，伊朗，德黑兰11365ORG 。

化学毕业论文英文献及翻译负载水杨醛1,3丙二酸二异丙酯二亚胺(BSPDI)的活性炭分离富集食物样品中某些重金属——火焰原子吸收光谱法测定摘要:在已有的报导中有一种灵敏而又简单的方法，能同时富集实际样品3+3+2+2+2+2+中的Cr、Fe、Cu、Ni、Co和Zn。

在该方法的基础上，将BSPDI 负载-1-1到活性炭上，再用8ml 2mol.L的硝酸的丙酮溶液或10ml 4mol.L的硝酸溶液对改性的活性炭洗提后吸附金属。

经调查分析，包括采样体积和PH值都是影响结果的分析参数。

检测分析物的残留物上的基质离子的影响，通常分析物的回收率是能测定的。

该方法已成功地应用于对一些食物样品中某些金属的内容评价。

1、介绍在包括自然水域的环境样品中，对微量金属的测定是为了表明生态污染程度和有关健康问题。

通常先确定所分离的元素是样品的主要组成部分，而后才涉及到时对这些微量组成的分离富集。

对微量金属的分析存在于各种样品中，像自然界的废水，泥沙和一些分析技术能直接测定的组织。

比如由于其他离子的基质影响、样品中金属离子的浓度转低和选择性低灵敏性低的分析技术而使原子吸收方法就不能用来真接测定。

事实上，固相萃取是一个强大的工具，能分离富集各种无机有机分析物。

在技术上它有风几个优点:固相稳定性好，可重复性好，能达到较高的富集效果，分离富集的动力条件温和，无需特殊的有机溶剂，试剂消耗低产生费用小。

几个选择性的用物理负载或化学绑定的鳌合剂等不同载体的固相萃取物已经准备好，例如:硅胶，活性炭，涂SDS氧化铝，改性硅藻土载体，标记离子聚合物，XAD-2000安伯来树脂。

活性炭是一种广泛应用在水、高纯度物质、蔬菜样品等分析物的多元微量富集的收集物。

一般使用活性炭对金属富集的方法是通过简单调整水溶液的PH到适当的值后与金属进行螯合，此过程的缺点是它需要一系列的络合步骤，因此，最近提出使用螯合活性炭。

金属螯合物可以提供高选择性和高富集效果，寻找这样一种分离富集技术。

由从粉煤灰中制取的硫酸铝盐合成氧化铝姓名：曹巍巍学号：2011200387 学院：化工学院摘要：由粉煤灰制得的NH4Al(SO4)2和氨在水中适宜的PH环境下可制得高纯度氧化铝（>99.9%）。

用XRD、TG/DTA、SEM和激光分散技术来检测热源（微波对硫酸铝铵分解和氧化铝性质的影响。

和传统的加热方法相比，微波加热来分解硫酸铝铵以制得更高比表面积的α-Al2O3粉末。

关键词：硫酸铝盐、粉煤灰、微波加热1、简介NH4Al(SO4)2是一种制备高纯度的活性氧化铝的潜在原料[1-3],硫酸铝盐通常是一种从含铝原材料中生产氧化铝的中间材料[4-5]。

硫酸铝盐的分解和生成物向氧化铝的转化在相关文献中已有报告[1-3,6]，但总体上结果还有一些分歧。

很多社会学家和相关的科学家对回收工业废物来制取高价值的材料很感兴趣。

在应用热点的地区，从大量的由煤燃烧产生的粉煤灰中进行资源回收是一个制得关注的问题。

粉煤灰由主要含有SiO2、Al2O3的无机粒子组成，这些粒子通常以煤胞的形式存在。

Al2O3是一种普遍使用的高性能原料，从粉煤灰中合成Al2O3具有很大的商业利益。

粉煤灰含有大量的杂质，如Fe2O3、Na2O、K2O、P2O5、MaO、MgO、CaO 和SiO2[7]，这样纯粹的用酸或碱来直接提取纯净的氧化铝是很困难的。

一种从粉煤灰中获取高纯氧化铝的方法就是把硫酸铝盐作为中间产物来制。

将硫酸铝盐作为中间产物的优点就使通过直截了当的可溶沉淀物的过程来提高纯度。

和传统的加热过程相比，微波加热有它自身的优点，它具有选择性、直接性、内部性、控制性。

所以，微波在材料制备中广泛地应用[8-10]。

用酸可加速有机材料和无机材料的溶解过程，这是由于微波产生的内部热量引起的[11,12]。

目前工作的目的就是促进回收粉煤灰及生产高纯度氧化铝。

微波加热的影响和由粉煤灰制得的Al的热效应已经进入研究，氧化铝也已表征。

2、实验过程粉煤灰原片包含了23.29% Al2O3的和53.83%的SiO2，，它包含了大量的硅酸盐矿物质，它是一种混合的鳞片象和近球面形颗粒，比表面积为3.82m2/g,凝聚的大小为42.1μm（<90%）.粉煤灰在600℃下在空气中焙烧2小时以出去残留的碳，随后在乙醇中球磨24小时，经过旋转真空蒸发后，干燥的粉末研磨到可通过200目的筛。

英语文献翻译学院：化学化工学院班级：应化1106姓名：***吴海军学号：***********20110222227Quantifying the Cluster of Differentiation 4 Receptor Density on Human T Lymphocytes Using Multiple Reaction Monitoring Mass Spectrometry多反应监测质量光谱法应用于人类T淋巴细胞量化分化抗原簇4受体密度ABSTRACT: Cluster of differentiation 4 (CD4) is an important glycoprotein containing four extracellular domains, a transmembrane portion and a short intracellular tail. It locates on the surface of various types of immune cells and performs a critical role in multiple cellular functions such as signal amplification and activation of T cells. It is well-known as a clinical cell surface protein marker for study of HIV progression and for defining the T helper cell population in immunological applications. Moreover, CD4 protein has been used as a biological calibrator for quantification of other surface and intracellular proteins. However, flow cytometry, the conventional method of quantification of the CD4 density on the T cell surface depends on antibodies and has suffered from variables such as antibody clones, the fluorophore and conjugation chemistries, the fixation conditions, and the flow cytometric quantification methods used. In this study, we report the development of a highly reproducible nano liqui d chromatography−multiple reaction monitoring mass spectrometry-based quantitative method to quantify the CD4 receptor density in units of copy number per cell on human CD4+ T cells. The method utilizes stable isotope-labeled full-length standard CD4 as an internal standard to measure endogenous CD4 directly, without the use of antibodies. The development of the mass spectrometry-based approach of CD4 protein quantification is important as a complementary strategy to validate the analysis from the cytometry-based conventional method. It also provides new support for quantitative understanding and advanced characterization of CD4 on CD4+ T cells.摘要：集群分化4(CD4)是一种重要的糖蛋白，它包含四个胞外区域,横跨膜的部分和短的细胞内尾巴。

关于化学英文作文英文：Chemistry is a fascinating subject that deals with the study of matter and its properties. As a chemistry student, I have learned about various chemical reactions, the periodic table, and the behavior of atoms and molecules. One of the most interesting topics I have studied is acid-base chemistry.Acids and bases are two types of chemical compoundsthat have opposite properties. Acids are substances that donate hydrogen ions (H+) in a solution, while bases are substances that accept hydrogen ions. The pH scale is used to measure the acidity or basicity of a solution. A pH of 7 is considered neutral, while lower values indicate acidity and higher values indicate basicity.One of the most common examples of acid-base chemistry is the reaction between an acid and a base to form a saltand water. This is known as a neutralization reaction. For example, when hydrochloric acid (HCl) is mixed with sodium hydroxide (NaOH), the resulting reaction produces sodium chloride (NaCl) and water (H2O).Another interesting aspect of acid-base chemistry isthe concept of acid-base indicators. These are substances that change color depending on the pH of the solution they are in. One example is litmus paper, which turns red in acidic solutions and blue in basic solutions.Overall, studying acid-base chemistry has helped me understand the behavior of different chemical compounds and their reactions. It has also given me a deeper appreciation for the complexity and beauty of the natural world.中文：化学是一个迷人的学科，涉及物质及其性质的研究。

化学文献及翻译10化二郑博201006010123Operation of plate rectification tower Abstract:The influencing factors,abnoimal phenomenon and rectification process were analyzed to direct actual operationKey words: rectification tower,recification,reboiler,operationDistillation column is a multi-stage partial vaporization and partial condensation according to the different components in the mixture volatility in each floor tower board to achieve the separation of a mixture of various components of the tower gas-liquid contact device, also known as distillation. A plate column and packed column types. According to mode of operation are divided into continuous distillation and batch distillation. Steam from the bottom of the column entry, and the decline in liquid countercurrent contact with the two in contact, the drop in the volatile liquid (low boiling point) components is continuously transferred to the steam. The difficulty of steam volatile (high boiling) component continued to decline in the transfer of liquid, steam the closer the top of the tower, the higher the concentration of its volatile components, while the decline in the closer tower bottom liquid, its hard to be more volatile components rich set, to achieve component separation. Steam rising from the top of the tower into the condenser, the liquid part of the condensate as reflux liquid to return into the distillation tower, the rest is removed as distillate. Tower bottom outflow of liquid, some of which into the reboiler, thermal evaporation, the steam back to tower, and the other part of the liquid as residua release.Compared with other chemical unit operations,distillation unit,although relatively simple,single production run that often appear in a variety of problems affecting the operation of the distillation unit,leading to tower top orbottom of product failure,severe constraints of production equipmentthe operation resulting in product loss.1.Regular changes in process conditions of distillation column 1.1 Reboiler temperatureUnder the same operating pressure,raising the temperature of the reboiler,the volatile components in the tower liquid to reduce,at the same time,the rising vapor velocity increases,and help to improve the efficiency of mass transfer.If products fromthe top of the tower,the tower reactor discharge of difficult volatiles volatile components to reduce and reduce losses.If the tower reactor effluents for the product,it can improve product quality tower discharge of volatile components entrained difficult nolatile components increased,thereby increasing the losses.In balanced operation,the reactor temperature is suddenly increased,and it too late to adjust the pressure and temperature will inevitably lead to the reboiler fluid is steam-air, the pressure increased.At this time,the tower gas,liquid composition changes,the restructuring were likely to be steamed to the top of the tower,so that the failure of top product.1.2 Operating pressureIn the case of certain operating temperature,increasing the operating pressure can increase the productive capacity of the tower,so that stable operation,but the content of volatile group in the tower reactor products.In distillation,often provides for the adjustment range of the operating pressure.When the fallout of the operating pressure by extmrnal factors,were destroyed,the normal operation of the tower will be completely destroyed.1.3 Feeding temperature1.3.1Condensate feed,the feed temperature is lower than the temperature of the feeding board,and added if all the material into the stripper segment,stripping segment load increases,the reboiler consumption increase in the amount of steam,and the top of the tower is difficult volatile group were lower.1.3.2Saturated steam feed,the feed material temperature is higher than the temperature of feed board,all the material of the feed into the rectifying section and stripping section of the load reduction,and increased load of the rectifying section,make the top product quality reduce.1.4 Feeding quantity and composition changesChanges in the feedstock of a direct impact on the change of the amount of steam,the latter increase will produce entrained,even flooding.The feedstock is too low,the operation is not good to maintain the balance of the tower,the steam veloc ity decreases,the plate is prone to leakage,the rectification efficiency is low.Inthe low-load operation,may be appropriate to increase the reflux ratio,the tower operating in a load lower limit above normal and stable operation in order to maintain the tower.Feeding component of the changes directly affect the product quality.Increased restructuring concentration increase in the rectifying section load separation is notgood,the results of restructuring were brought to the top of tower,causing the top of the tower of inferior quality.Product from the reboiler,the top of the tower losses increase.If the concentration of the volatile group in the feeding group were increased,and the stripping section of the load increases,may be poor due to the separation caused by the tower reactor products of inferior quality,which entrained volatile components increased.Feeding restructuring concentration increased,the feeding mouth move down and vice versa,then move up.The same time,operating temperature,back flow and operating pressure must be adjusted accordingly in order to ensure the stability of the distillation operation.Distillation,increasing the reflux ratio,can improve the quality of the product,but the reflux ratio is too large,the inner loop of the tower increased,increasing energy consumption.Reduction of the reflux ratio,the tower gas-liquid contact is not good,the balance to damaged and therefore the mass transfer efficiency decreased.The same time,the operating pressure drop,difficult volatile components easily brought to the top of the tower,resulting in a substandard product.2 Anomalies in the distillation column during operation2.1 Plate capacityRectifying section tray downcomer overflow liquid transportation,however,that the tower upper part of the beginning of flooding,a phenomenon known as downcomer obstruction or liquid flooding.Its causes is to block the liquid leaving the tower board level rise in the downcomer plate between mist entrained excessive leaving the tray efficiency to reduce entrainment of this phenomenon is known as the excessive fog or steam flooding,the reason is the relativein the gas while the tower board bubbling area is too small.2.2 Plate foulingSediment cumulative to the board of board of the tower is an important issue,trays of dirt will tower premature flooding will reduce the plate efficiency.Plate scaling phenomenon:(1)The reflux ratio is not high on liquid pan;(2)The pressure drop increase between the tray;(3)Increase the reflux ratio on the bottom of the column temperature,flow or reboiler load does not have any impact,if the reflux ratio to the heat balance and material balance of 20% to 30%,while the tower did not change significantly,then the tower must be completely full of liquid.The amount of returning tower direct stream gas pipeline through the top of the tower back to the reflux tank.2.3 Slug flows in the riserSlug flow in the riser is a distillation column running unstable,may be caused due to an unstable gas-liquid mixture flow in the vertical pipeline.Reflux tank is elevated at the of the condenser by the condenser discharge logistics is that part of the pipeline between the gas-liquid two-phase mixture,the condenser and reflux tank is called the riser.Generate a liquid column in the riser flow rate is too low will result in two-phase separation,the distillation column to produce a back pressure,this liquid column intermittently be introduced after the riser,back pressure will weaken,then the risergradually being filled with liquid,such slug flow will cause the tower pressureperiodic pulse of change.Abnormal factors cause distillation column plate was washed away,condenser corrosion,clogged caondenser,not condensable gas influence condenser.3.ReboilerReboiler in the distillation column occupies a very important position,it used to bebottom after the vaporization of the liquid part of the back to the distillation column,two phases of the tower gas-liquid contact and mass transfer to proceed.Which used the vertical thermal siphon reboiler,which is a vertical placement of the shell and tube heat exchanger.Partial vaporization of liquid in the bottom-up tube passes through the heat exchanger,heating the heat carrier in the shell.V ertical thermal siphon reboiler features:(1)cycle driving force:the density of the reactor liquid and the heat exchanger tube gas-liquid mixture;(2)compact,small footprint,high heat transfer coefficient;(3)of the shell can not be mechanically cleaned,not suitable for hightower reactor,heat transfer medium viscosity,or dirty;(4)provide the space and buffer zones of the gas-liquid separator.Factors that determine the distillation column capacity restricted,find the reboiler failure is the most laborious,the distillation column by steam reboiler.(1)gas-barrier drain valve failure;(2)steam condensate collected indoor pressure is too large;(3)the condensate liquid seal failure.Hydrophobic failure caused by hydrophobic failure factors:3.1 Thermosiphon rebiler failureReboiler liquid inlet pipe and outlet pipe cold liquid mixture exists between the density difference is the density difference driving the process of processing liquid flow through the reboiler.When tower humoral bit elevated to the reboiler back to the liquid nozzle height,siphon circulation will be impeded.The circulation rate reductionwill result in the reduction of heat transfer,thus the cover back to the fluid nozzle is clearly an important reason for fluctuations in the reboiler duties.3.2 Non-condensable gas in the water vaporSteam reboiler to run the process,water vapor may be non-condensable gases,or the reboiler leak,the hydrocarbon vapor or other non-condensable gas into the reboiler,the non-condensable gas into the reboiler pipingthereby reducing the heat transfer capacity of the reboiler with the distillation column within a circulating fluid,thus causing the reboiler heat transfer efficiency decreased.4 ConclusionIn view of these problems often appear in a production run affect the operation of the distillion unit,leading ton the top of the tower or the bottom of prod uct failure,seriously restricting the production device to run resulting in product loss.In order to avoid such things from bappening,the operator should do the following:4.1 storage and transportation of materialsPlate column distillation process must be set in place a number of different volume raw material storage tanks,pumps and all kinds of heat exchanger has been temporarily stored,transported and preheating(cooling)of materials used,in order to protect the device can be a continuous and stable operation.4.2 Necessary means of detectionIn order to facilitate the resolution of the problem in the operation shall be the appropriate place in the process to set the necessary instrumentation,as well as to obtain the pressure,temperature and other parameters.In addition,often set in a particular place manholes and hand holes,so that regular testing and maintenance.4.3 Adjustment deviceState parameters are not in the actual production value should be placed in the appropriate location of a certain number of the valve to be adjusted to achieve the production requirements,can be a double adjustment,that is both automatic and manual adjustment coexist,and at any timeswitch.。

毕业设计论文化学系毕业论文外文文献翻译中英文英文文献及翻译A chemical compound that is contained in the hands of the problemsfor exampleCatalytic asymmetric carbon-carbon bond formation is one of the most active research areas in organic synthesis In this field the application of chiral ligands in enantioselective addition of diethylzinc to aldehydes has attracted much attention lots of ligands such as chiral amino alcohols amino thiols piperazines quaternary ammonium salts 12-diols oxazaborolidines and transition metal complex with chiral ligands have been empolyed in the asymmetric addition of diethylzinc to aldehydes In this dissertation we report some new chiral ligands and their application in enantioselective addition of diethylzinc to aldehydes1 Synthesis and application of chiral ligands containing sulfur atomSeveral a-hydroxy acids were prepared using the literature method with modifications from the corresponding amino acids valine leucine and phenylalanine Improved yields were obtained by slowly simultaneous addition of three fold excess of sodium nitrite and 1 tnolL H2SO4 In the preparation of a-hydroxy acid methyl esters from a-hydroxy acids following the procedure described by Vigneron a low yield 45 was obtained It was found that much better results yield 82 couldbe obtained by esterifying a-hydroxy acids with methanol-thionyl chlorideThe first attempt to convert S -2-hydroxy-3-methylbutanoic acid methyl ester to the corresponding R-11-diphenyl-2-mercapto-3-methyl-l-butanol is as the following S-2-Hydroxy-3-methylbutanoic acid methyl ester was treated with excess of phenylmagnesium bromide to give S -11-diphenyl-3-methyl-12-butanediol which was then mesylated to obtain S -11-diphenyl-3-methyl-2-methanesulfonyloxy -l-butanol Unfortunately conversion of S-11-diphenyl-3-methyl-2- methanesulfonyloxy -l-butanol to the corresponding thioester by reacting with potassium thioacetate under Sn2 reaction conditions can be achieved neither in DMF at 20-60 nor in refluxing toluene in the presence of 18-crown-6 as catalyst When S -1ll-diphenyl-3-methyl-2- methane sulfonyloxy -l-butanol was refluxed with thioacetic acid in pyridine an optical active epoxide R-22-diphenyl -3-isopropyloxirane was obtained Then we tried to convert S -11-diphenyl-3-methyl-l2-butanediol to the thioester by reacting with PPh3 DEAD and thioacetic acid the Mitsunobu reaction but we failed either probably due to the steric hindrance around the reaction centerThe actually successful synthesis is as described below a-hydroxy acid methyl esters was mesylated and treated with KSCOCH3 in DMF to give thioester this was than treated with phenyl magnesium bromide to gave the target compound B-mercaptoalcohols The enantiomeric excesses ofp-mercaptoalcohols can be determined by 1H NMR as their S -mandeloyl derivatives S -2-amino-3-phenylpropane-l-thiol hydrochloride was synthesized from L-Phenylalanine L-Phenylalanine was reduced to the amino alcohol S -2-amino-3-phenylpropanol Protection of the amino group using tert-butyl pyrocarbonate gave S -2-tert-butoxycarbonylamino-3-phenylpropane-l-ol which was then O-mesylated to give S -2-tert-butoxycarbonylamino-3-phenylpropyl methanesulfonate The mesylate was treated with potassium thioacetate in DMF to give l-acetylthio-2-tert-butoxycarbonylamino-3-phenylpropane The acetyl group was then removed by treating with ammonia in alcohol to gave S -2-tert-butoxycarbonylamino-3-phenyl-propane-l-thiol which was then deprotected with hydrochloric acid to give the desired S-2-amino-3-phenylpropane-1-thiol hydrochlorideThe enantioselective addition of diethylzinc to aldehydes promoted by these sulfur containing chiral ligands produce secondary alcohols in 65-79 Synthesis and application of chiral aminophenolsThree substituted prolinols were prepared from the naturally-occurring L-proline using reported method with modifications And the chiral aminophenols were obtained by heating these prolinols with excess of salicylaldehyde in benzene at refluxThe results of enantioselective adBelow us an illustration forexampleN-Heterocyclic carbenes and L-Azetidine-2-carboxylicacidN-Heterocyclic carbenesN-Heterocyclic carbenes have becomeuniversal ligands in organometallic and inorganic coordination chemistry They not only bind to any transition metal with low or high oxidation states but also to main group elements such as beryllium sulfur and iodine Because of their specific coordination chemistry N-heterocyclic carbenes both stabilize and activate metal centers in quite different key catalytic steps of organic syntheses for example C-H activation C-C C-H C-O and C-N bond formation There is now ample evidence that in the new generation of organometallic catalysts the established ligand class of organophosphanes will be supplemented and in part replaced byN-heterocyclic carbenes Over the past few years this chemistry has become the field of vivid scientific competition and yielded previously unexpected successes in key areas of homogeneous catalysis From the work in numerous academic laboratories and in industry a revolutionary turningpoint in oraganometallic catalysis is emergingIn this thesis Palladium Ⅱ acetate and NN"-bis- 26-diisopropylphenyl dihydro- imidazolium chloride 1 2 mol were used to catalyze the carbonylative coupling of aryl diazonium tetrafluoroborate salts and aryl boronic acids to form aryl ketones Optimal conditions include carbon monoxide 1 atm in 14-dioxane at 100℃ for 5 h Yields for unsymmetrical aryl ketones ranged from 76 to 90 for isolated materials with only minor amounts of biaryl coupling product observed 2-12 THF as solvent gave mixtures of products 14-Dioxane proved to be the superior solvent giving higher yieldsof ketone product together with less biphenyl formation At room temperature and at 0℃ with 1 atm CO biphenyl became the major product Electron-rich diazonium ion substrates gave a reduced yield with increased production of biaryl product Electron-deficient diazonium ions were even better forming ketones in higher yields with less biaryl by-product formed 2-Naphthyldiazonium salt also proved to be an effective substrate givingketones in the excellent range Base on above palladium NHC catalysts aryl diazonium tetrafluoroborates have been coupled with arylboron compounds carbon monoxide and ammonia to give aryl amides in high yields A saturated yV-heterocyclic carbene NHC ligand H2lPr 1 was used with palladium II acetate to give the active catalyst The optimal conditions with 2mol palladium-NHC catalyst were applied with various organoboron compounds and three aryl diazonium tetrafluoroborates to give numerous aryl amides in high yield using pressurized CO in a THF solution saturated with ammonia Factors that affect the distribution of the reaction products have been identified and a mechanism is proposed for this novel four-component coupling reactionNHC-metal complexes are commonly formed from an imidazolium salt using strong base Deprotonation occurs at C2 to give a stable carbene that adds to form a a-complex with the metal Crystals were obtained from the reaction of imidazolium chloride with sodium t- butoxide Nal and palladium II acetate giving a dimeric palladium II iodide NHC complex The structure adopts a flat 4-memberedring u2 -bridged arrangement as seen in a related dehydro NHC complex formed with base We were pleased to find that chloride treated with palladium II acetate without adding base or halide in THF also produced suitable crystals for X-ray anaysis In contrast to the diiodide the palladium-carbenes are now twisted out of plane adopting a non-planar 4-ring core The borylation of aryldiazonium tetrafluoroborates with bis pinacolatoborane was optimized using various NHC ligand complexes formed in situ without adding base NN"-Bis 26-diisopropylphenyl-45-dihydroimidazolium 1 used with palladium acetate in THF proved optimal giving borylated product in 79 isolated yield without forming of bi-aryl side product With K2CO3 and ligand 1 a significant amount of biaryl product 24 was again seen The characterization of the palladium chloride complex by X-ray chrastallography deL-Azetidine-2-carboxylic acidL-Azetidine-2-carboxylic acid also named S -Azetidine-2-carboxylic acid commonly named L-Aze was first isolated in 1955 by Fowden from Convallaria majalis and was the first known example of naturally occurring azetidine As a constrained amino acid S -Azetidine-2-carboxylic acid has found many applications in the modification of peptides conformations and in the area of asymmetric synthesis which include its use in the asymmetric reduction of ketones Michael additions cyclopropanations and Diels-Alder reactions In this dissertation five ways for synthesize S-Azetidine-2-carboxylic acid were studied After comparing all methods theway using L-Aspartic acid as original material for synthesize S-Azetidine-2-carboxylic acid was considered more feasible All mechanisms of the way"s reaction have also been studied At last the application and foreground of S -Azetidine-2-carboxylic acid were viewed The structures of the synthetic products were characterized by ThermalGravity-Differential Thermal Analysis TG-DTA Infrared Spectroscopy IR Mass Spectra MS and 1H Nuclear Magnetic Resonance 1H-NMR Results showed that the structures and performances of the products conformed to the anticipation the yield of each reaction was more than 70 These can conclude that the way using L-Aspartie acid as original material for synthesize S -Azetidine-2-carboxylic acid is practical and effective杂环化合物生成中包含手性等问题如催化形成不对称碳碳键在有机合成中是一个非常活跃的领域在这个领域中利用手性配体诱导的二乙基锌和醛的不对称加成引起化学家的广泛关注许多手性配体如手性氨基醇手性氨基硫醇手性哌嗪手性四季铵盐手性二醇手性恶唑硼烷和过渡金属与手性配体的配合物等被应用于二乙基锌对醛的不对称加成中在本论文中我们报道了一些新型的手性配体的合成及它们应用于二乙基锌对醛的不对称加成的结果1含硫手性配体的合成和应用首先从氨基酸缬氨酸亮氨酸苯丙氨酸出发按照文献合成α-羟基酸并发现用三倍量的亚硝酸钠和稀硫酸同时滴加进行反应能适当提高反应的产率而根据Vigneron等人报道的的方法用浓盐酸催化从α-羟基酸合成α-羟基酸甲酯时只能获得较低的产率改用甲醇-二氯亚砜的酯化方法时能提高该步骤的产率从 S -3-甲基-2-羟基丁酸甲酯合成 R -3-甲基-11-二苯基-2-巯基-1-丁醇经过了以下的尝试 S -3-甲基-2-羟基丁酸甲酯和过量的格氏试剂反应得到 S -3-甲基-11-二苯基-12-丁二醇进行甲磺酰化时位阻较小的羟基被磺酰化生成 S -3-甲基-11-二苯基-2- 甲磺酰氧基 -1-丁醇但无论将 S -3-甲基-11-二苯基-2- 甲磺酰氧基 -1-丁醇和硫代乙酸钾在DMF中反应 20～60℃还是在甲苯中加入18-冠-6作为催化剂加热回流都不能得到目标产物当其与硫代乙酸在吡啶中回流时得到的不是目标产物而是手性环氧化合物 R -3-异丙基-22-二苯基氧杂环丙烷从化合物 S -3-甲基-11-二苯基-12-丁二醇通过Mitsunobu反应合成硫代酯也未获得成功这可能是由于在反应中心处的位阻较大造成的几奥斯塑手村犯体的合成裁其在不对称奋成中肠左用摘要成功合成疏基醇的合成路是将a-轻基酸甲酷甲磺酞化得到相应的磺酞化产物并进行与硫代乙酸钾的亲核取代反应得到硫酷进行格氏反应后得到目标分子p一疏基醇用p一疏基醇与 R 义一一甲氧基苯乙酞氯生成的非对映体经H侧NM吸测试其甲氧基峰面积的积分求得其ee值 3一苯基一氨基丙硫醇盐酸盐从苯丙氨酸合成斗3一苯基一氨基丙醇由L一苯丙氨酸还原制备氨基保护后得到习一3一苯基一2一叔丁氧拨基氨基一1一丙醇甲磺酞化后得到习一3一苯基一2一叔丁氧拨基氨基一1一丙醇甲磺酸酷用硫代乙酸钾取代后得匀一3-苯基一2一叔丁氧拨基氨基一1一丙硫醇乙酸酷氨解得习一3一苯基一2一叔丁氧拨基氨基一1一丙硫醇用盐酸脱保护后得到目标产物扔3一苯基屯一氨基丙硫醇盐酸盐手性含硫配体诱导下的二乙基锌与醛的加成所得产物的产率为65一79值为O井92手性氨基酚的合成和应用首先从天然的L一脯氨酸从文献报道的步骤合成了三种脯氨醇这些手性氨基醇与水杨醛在苯中回流反应得到手性氨基酚手性氨基酚配体诱导下的二乙基锌与醛的加成所得产物的产率为45一98值为0一90手性二茂铁甲基氨基醇的合成和应用首先从天然氨基酸绿氨酸亮氨酸苯丙氨酸和脯氨酸合成相应的氨基醇这些氨基醇与二茂铁甲醛反应生成的NO一缩醛经硼氢化钠还原得到手性二茂铁甲基氨基醇手性二茂铁甲基氨基醇配体诱导下的二乙基锌与醛的加成所得产物的产率为66一97下面我们举例说明一下例如含氮杂环卡宾和L-氮杂环丁烷-2-羧酸含氮杂环卡宾含氮杂环卡宾已广泛应用于有机金属化学和无机配合物化学领域中它们不仅可以很好地与任何氧化态的过渡金属络合还可以与主族元素铍硫等形成配合物由于含氮杂环卡宾不但使金属中心稳定而且还可以活化此金属中心使其在有机合成中例如C-H键的活化C-CC-HC-O和C-N键形成反应中有着十分重要的催化效能现有的证据充分表明在新一代有机金属催化剂中含氮杂环卡宾不但对有机膦类配体有良好的互补作用而且在有些方面取代有机膦配体成为主角近年来含氮杂环卡宾及其配合物已成为非常活跃的研究领域在均相催化这一重要学科中取得了难以想象的成功所以含氮杂环卡宾在均相有机金属催化领域的研究工作很有必要深入地进行下去本文研究了乙酸钯和NN双 26-二异丙基苯基 -45-二氢咪唑氯化物1作为催化剂催化芳基四氟硼酸重氮盐与芳基硼酸的羰基化反应合成了一系列二芳基酮并对反应条件进行了优化使反应在常温常压下进行一个大气压的一氧化碳14-二氧杂环己烷作溶剂100℃反应5h 不同芳基酮的收率达7690仅有微量的联芳烃付产物 212 反应选择性良好当采用四氢呋喃或甲苯作溶剂时得到含较多副产物的混合物由此可以证明14-二氧杂环己烷是该反应最适宜的溶剂在室温或0℃与一个大气压的一氧化碳反应联芳烃变成主产物含供电子取代基的芳基重氮盐常常给出较低收率的二芳基酮而含吸电子取代基的芳基重氮盐却给出更高收率的二芳基酮及较少量的联芳烃付产物实验证明2-萘基重氮盐具有很好的反应活性和选择性总是得到优异的反应结果在此基础上由不同的芳基四氟硼酸重氮盐与芳基硼酸一氧化碳和氨气协同作用以上述含氮杂环卡宾作配体与乙酸钯生成的高活性含氮杂环卡宾钯催化剂催化较高收率地得到了芳基酰胺优化的反应条件是使用2mol的钯-H_2IPr 1五个大气压的一氧化碳以氨气饱和的四氢呋喃作溶剂由不同的有机硼化合物与三种芳基重氮盐的四组份偶联反应同时不仅对生成的多种产物进行了定 L-氮杂环丁烷-2-羧酸L-氮杂环丁烷-2-羧酸又称 S -氮杂环丁烷-2-羧酸简称为L-Aze1955年由Fowden从植物铃兰 Convallaria majalis 中分离得到成为第一个被证实的植物中天然存在的氮杂环丁烷结构作为一种非典型的氨基酸已经发现 S -氮杂环丁烷-2-羧酸可广泛用于对多肽结构的修饰以及诸如不对称的羰基还原Michael 加成环丙烷化和Diels-Alder反应等不对称合成中的多个领域本文通过对 S -氮杂环丁烷-2-羧酸合成路线的研究综述了五种可行的合成路线及方法通过比较选用以L-天冬氨酸为初始原料合成 S -氮杂环丁烷-2-羧酸的路线即通过酯化反应活泼氢保护格氏反应内酰胺化反应还原反应氨基保护氧化反应脱保护等反应来合成 S -氮杂环丁烷-2-羧酸分析了每步反应的机理并对 S -氮杂环丁烷-2-羧酸的应用及前景给予展望通过热分析红外质谱核磁等分析手段对合成的化合物的结构进行表征结果表明所得的产物符合目标产物所合成的化合物的结构性能指标与设计的目标要求一致每步反应的收率都在70％以上可以判定以L-天冬氨酸为初始原料合成 S -氮杂环丁烷的路线方案切实可行。

Three Common Details of The Compressor Failure AnalysisCompressor Fault Analysis (1) - motor burnedMotor compressor (hereinafter referred to as the compressor) of the fault can be divided into motor failure and mechanical failure (including the crankshaft, connecting rod, piston, valve, cylinder head pad, etc.). Mechanical failure is often the motor overload or stall, is one of the main motor damage.Damage mainly to the motor stator winding insulation damage (short circuit) and the circuit and so on. Stator windings was found damaged hard time, could eventually lead to winding burned. Winding burned, cover up some cause or direct cause of the phenomenon of burning, making the subsequent analysis and cause investigation more difficult.However, the operation of the motor power input is inseparable from the normal, reasonable motor load, good heat dissipation and winding wire insulation layer of protection. From several aspects, not difficult to find reason than burnt windings are six: (1) abnormal load and stall; (2) Winding short circuit caused by metal shavings; (3) contactor problems; (4) Power phase and voltage abnormalities; (5) inadequate cooling; (6) compressor vacuum. In fact, many factors contributed to the more common motor damage.1. Abnormal loads and stallMotor load requirements, including compressed gas load and the load required to overcome mechanical friction. Pressure ratio is too large, or the pressure is too large, the compression process will be more difficult; and increased friction caused by lubrication failure, and extreme cases of motor stall, will greatly increase the electrical load. Lubrication failure, friction increases, is the leading cause of abnormal load. Back to the diluted lubricating oil, oil heat, oil coking deterioration and lack of oil and so will disrupt normal lubrication, leading to lubrication failure. Back to the diluted lubricating oil, affecting the normal friction surface film formation, or even washed away the original film, increasing friction and wear. Compressor overheating will cause the thinning or even high-temperature coking oil, affecting the normal film formation. System back to the oil well, the compressor short of oil, they can not maintain normal lubrication. High-speed rotating crankshaft, connecting rod piston speed movement, there is no friction surface protection film will quickly heat up, local high-temperature rapid evaporation of the oil or coke, to make it more difficult to lubricate the parts, a few seconds can cause severe localized wear. Lubrication failure, local wear, the need for greater torque to the crankshaft. Low-power compressor (such as refrigerators, home air conditioning compressor) as the motor torque, lubrication failure often occurs after the stall (the motor can not rotate) phenomenon, and enter the "stall - Thermal protection - Locked" death cycle, motor burn only a matter of time. The high-power semi-closed compressor motor torque large, local wear will not cause stall, the motor power will be within a certain range increases with the load, causing more serious wear and tear, and even lead to bite cylinder (live seca in cylinder), rod fracture and other serious damage.When the current stall (stall current) is about 4-8 times the normal running current. The moment of starting the motor, the current reached a peak close to or stall current.Because the resistance heat release proportional to the square with the current, start and stall when the winding current will heat up quickly. Thermal protection can protect the electrode in the stall, but generally will not have a response soon, can not prevent such frequent starting winding due to temperature changes. Frequent starts and abnormal load, so that the test winding subjected to high temperature will reduce the magnet wire insulation.In addition, the compressed gas with the compression ratio will be required to increase the load and pressure increases. Therefore, the high temperature compressor for low temperature, or low compressor for high temperature, will affect the electrical load and heat, is not appropriate, will shorten the electrode life.Winding insulation deterioration, if there are other factors (such as metal shavings form conductive loops, acid oil, etc.) with, it is easy to cause a short circuit and damage.2. Scrap metal caused by short circuitWinding metal particles are mixed and ground insulation value of the low short-circuit the culprit. The normal vibration of the compressor running, and every time you start winding by the magnetic force of the pipe, will promote inclusion in the winding and the winding metal shavings between the relative motion between the magnet wire and friction. Sharp edges will scratch the enameled metal shavings insulation, causing short circuits. Sources including the construction of metal debris left behind by the brass shavings, welding slag, compressor internal parts wear and damage (such as broken valves), the fall of the metal shavings and so on. For the closed compressor (including the closed scroll compressor), the metal shavings or broken, would fall on the winding. For semi-hermetic compressors, and some particles with the gas and oil flow in the system, and finally assembled in the magnetic winding; and some metal shavings (such as bearing wear and stator and rotor wear (sweep bore) is generated) will be directly on the winding. Winding metal shavings gathered after a short circuit is only a matter of time.Need to draw particular attention to the two-stage compressor. In the two-stage compressor, back to the normal gas and oil directly back into the first grade (low grade) cylinder, compressed by the pressure of the cooling tube into the motor winding cavity, and the general single-stage compressor and then as second-class (high pressure stage cylinder.) Back to the gas with oil, the compression process has been skating on thin ice, if there are back to liquid again, the first stage cylinder valve can easily be broken. Broken by the pressure valve can enter the winding tube. Therefore, the two-stage compressor than the single-stage compressors are more likely to electrical short circuit caused by metal shavings.Unfortunately, things tend to conspire a piece of the compressor in the boot of a problem when the news channels is often the oil burning. Severe wear of metal surfaces when the temperature is very high, while oil above 175 º C at the start of coking. System, if there is more moisture (vacuum pits not ideal, big oil and refrigerant water, negative pressure air into the return pipe burst, etc.), lubricants acid may occur. Acidic oil will corrode copper and winding insulation layer, on the one hand, it can cause copper plating phenomenon; on the other hand, this acid containing copper atoms very poor insulation properties of lubricating oil, provided the conditions for the winding circuit.3. Contactor problemContacts is an important component in the motor control circuit, one of the best selection of irrational destruction of the compressor can be. The right choice according to the load contacts are extremely important.Contactor must be able to meet the harsh conditions, such as rapid cycling, continuous overload and low voltage. They must have enough surface area to distribute the heat generated by the load current, contact material should be selected to start or stall in such circumstances to prevent high current welding.For safe and reliable, while the compressor contactor to disconnect the three-phase circuit. Copeland is not recommended way to disconnect the two-phase circuits.In the United States, Copeland approved contactor must meet the following four:• contactor must meet ARI Standard 780-78, "Standard for special access" provisions of the work and testing guidelines.• The manufacturer must ensure that the contacts at room temperature in the lowe st 80% of nameplate voltage can be closed.• When using a single contactor, the contactor must be greater than the motor nameplate rated current rating (RLA). Meanwhile, the contactor must be able to withstand motor stall current. If there are other loads downstream of the contactor, such as electrical fans, and so must also be considered.• When using two contactors, each contactor rating of the sub-winding stall must be equal to or greater than the rating of the compressor stall half-winding.Contacts can not be less than the rated current of the compressor nameplate rated current. Size small or poor quality of contact can not withstand the compressor starts, stall, and low voltage high current impact, single-phase or multiphase prone to contact bounce, the phenomenon of welding or even fall off, causing electrical damage.Contact jitter frequently start and stop the motor contactor. Frequent motor starts, a huge starting current and heat, will aggravate the winding insulation aging. Each time you start, the magnetic torque to the motor windings have small mobile and mutual friction. If there are other factors with (such as metal shavings, poor insulation oil, etc.) can easily lead to short circuits between windings. Thermal protection system is not designed to prevent such damage. In addition, the jitter of the contactor coil easy to failure. If you have contact with the coil is damaged, prone to single-phase state.If the small selection of the contactor, the contact arc, and can not afford to open due to the frequent instability of circulatory arrest or heat generated by the voltage control loop may be welded together or from the contact frame in the loss. Welding of the contacts will have a permanent single-phase state, the overload protection device continuously cycle on and off.Needs to be stressed is that after the welding contactor, disconnect the compressor contactor power dependence of all the control loop (such as high and low pressure control, hydraulic control, defrost control, etc.) will all fail, the compressor is unprotected state. Therefore, when the motor burned, check the contacts are essential processes. Contacts lead to motor damage is often forgotten as a major reason.Compressor Fault Analysis (2) - liquid strike1. Processes and phenomena(1) suction valves are breakingCompressed gas compressor is a machine. Typically, compressed air piston 1450 times per minute (half-closed compressor), or 2900 times (all closed compressor), a suction or exhaust to complete the process time is 0.02 seconds or less. Suction and discharge valve plate of the size of the aperture and the suction valve sheet flexibility and strength are designed in accordance with the gas flow. The force from the perspective of the valve, the gas flow impact force is relatively uniform.The density of the liquid is dozens or even hundreds of times the gas, and thus the momentum of the liquid flow much larger than the gas, the impact force is also much larger. Mixed with more droplets aspirated into the cylinder when the flow is two-phase flow. Two-phase flow in the suction valve chip is not only the impact of high intensity and frequency, as if the typhoon beat mixed with pebbles at the window, the destructive self-evident. Is the liquid suction valve are breaking hit one of the typical characteristics and processes.(2) rod fractureCompression stroke of the time about 0.02 seconds, while the discharge process will be more short-lived. Or liquid droplets in the cylinder must be in such a short period of time discharged from the vent, the speed and momentum is significant. The case of exhaust valve and the suction valve sheet film the same, the difference is limited piece exhaust valve plate and spring-bit support is not easy to break. The impact of serious, limit deformation plate will tilt.If the liquid does not evaporate and discharge time cylinder, piston near top dead center when the compressed liquid, due to a very short time, the compressed liquid the process seems to be hit, also came in the metal cylinder head knocking. Compressed liquid is a liquid hammer or another part of the process.Instantly generate high-pressure liquid hit the broken ring of the great, the beginning of the familiar rod bending or breaking, the other pieces of compression force (valve plate, disc pads, crankshaft, piston, piston pin, etc.) will also be deformed or damage, but often overlooked, or confused with the exhaust pressure is too high. Maintenance of the compressor, people will be very easy to find bent or broken connecting rod, and give replacement, and forget to check whether there are other parts of deformed or damaged, thus laying the seeds for future failure.Attack caused by the fracture fluid is different from the axle rod and piston cylinder bite, it can tell. First, the liquid hit causing rod bent or broken in the short span of time, the rod ends of the piston and crankshaft motion freely, and not generally cause serious wear and tear or bite cylinder axle. Despite the broken piece suction valve, the valve can cause debris occasionally serious scratch piston and cylinder surface, but scratch the surface caused by wear and lubrication failure is very different. Secondly, the liquid caused by rod fracture attack is caused by stress, the connecting rod and a compression feature off stubble. Although the bite cylinder piston rod after the squeeze is also likely to fracture, but only to be stuck in the cylinder piston. Link broken axle after more different, connecting rod and crankshaft are badly scratched, resulting in a broken force is shear stress, are not the same broken stubble. Finally, and bite-cylinder front axle, the motor overload, severemotor heating, thermal protection will be action.2. ReasonsObviously, the compressor can cause the liquid fluid is nothing more than hit several sources as follows: 1) back to the fluid, which flows back to the compressor from the evaporator liquid refrigerant or lubricating oil; 2) starts with a liquid foam; 3) compressor lubricant too much. This paper will analyze each of these types of reasons.(1) back to the liquidTypically, back to the compressor run-time solution is the evaporator liquid refrigerant in the suction line back to the compressor through the phenomenon or process.For the refrigeration system expansion valve, expansion valve back to liquid and is closely related to improper selection and use. Expansion valve selection is too large, too small to set superheat, temperature of installation method is not correct or damaged insulation wrap, expansion valve failure can cause back to the fluid. For a small refrigeration system using capillary, the increase will cause excessive fluid back to liquid.Hot gas defrost system using prone to back solution. Regardless of the heat pump reversing valve operation, or by cooling hot gas bypass valve operation, hot gas defrost the evaporator after the formation of large amounts of liquid, the liquid refrigerant in the subsequent start of the run both possible and return to the compressor.In addition, severe frost evaporator fan failure or deterioration of heat transfer, no evaporation will cause the liquid back to liquid. Cold storage temperature fluctuations can also cause frequent reaction failures caused by the expansion valve back to liquid.Back to the liquid medium caused the accident hit mostly in air-cooled type (referred to as air-cooled or air cooled) semi-hermetic compressors and single two-stage compressors, compressor cylinders because they are directly connected with the return pipe, and once back to the fluid, easily lead to fluid strike accidents. Even if the strike did not cause fluid to return fluid into the cylinder will be diluted or washed away the wall of the piston and cylinder lubricating oil, increased piston wear.For the return air (refrigerant vapor) cooled semi-closed and closed compressor, back to the liquid rarely cause fluid attack. But it will dilute the crankcase oil. Contains large amounts of liquid refrigerant in the oil viscosity is low, the friction surface can not form a sufficient oil film, resulting in rapid wear of moving parts. In addition, the refrigerant oil in the transport process in the case of boiling heat will affect the normal transport lubricants. The farther from the pump, the more obvious the more serious problems. If a serious motor side bearing wear, the crankshaft to the side of the settlement could easily lead to the stator and the motor burned sweep Church.Obviously, back to the liquid solution will not only lead to strike, but also the wear of lubricating oil dilution. Wear and current load the motor will be greatly increased, over time will cause motor failure.Difficult to avoid the return liquid cooling system, installation of gas-liquid separator and taking the time to stop using the control can prevent or reduce the harm back to liquid. (2) start with liquidReturn air-cooled compressor is started, the crankcase oil is called the phenomenon of severe blistering start with liquid. When starting with a blistering fluid in the oil sight glass can be clearly observed. Start with the root cause of liquid dissolved in oil and submergedin the oil following a large number of the refrigerant, the pressure suddenly decreases suddenly boiling and cause blistering oil. This phenomenon is similar to our daily lives and suddenly open the coke cola bottle bubble phenomenon. The length of the duration of foaming agent into the area and cooling, usually a few minutes or ten minutes. The surface of a large number of bubbles floating in the oil, and even filled the crankcase. Once the cylinder through the suction inlet, the bubble will be reduced to liquid (a mixture of oil and refrigerant) can easily lead to fluid attack. Obviously, start with a liquid solution due to hit only occurs during the startup process.And back to the liquid is different from cause to start with liquid refrigerant is "refrigerant migration" of the way into the crankcase. Refrigerant migration is the compressor stops running, the evaporator refrigerant in gaseous form, through the trachea way back into the oil absorbed by the compressor or condensing in the compressor oil after mixing with the process or phenomenon.After the compressor is stopped, the temperature will decrease, and the pressure will rise. As the refrigerant vapor lubricant points down, it will absorb the oil surface of the refrigerant vapor, causing crankcase pressure lower than the evaporator pressure phenomenon. Lower oil temperature, the lower the vapor pressure of refrigerant vapor in the greater absorption of force. Evaporator to the crankcase vapor will slowly "migrate." In addition, if the compressor outside, cold weather or at night, the temperature is often lower than the indoor evaporator, the crankcase pressure there is low, the refrigerant can easily migrate to the compressor and into oil by condensation.Refrigerant migration is a very slow process. The longer the compressor is stopped, migrated to the oil in the refrigerant with it. Exist as long as the evaporator liquid refrigerant, this process will be conducted. As the refrigerant dissolved heavy oil, it will sink to the bottom of the crankcase, and oil floating in the above can also absorb more refrigerant.In addition to outside attack likely to cause liquid refrigerant migration will dilute the lubricating oil. Is very dilute oil pump to the friction surface, rinse out the original film may be washed, causing severe wear (a phenomenon often called refrigerant erosion). Wear transition with the gap will become larger, causing oil spills, thus affecting distant parts of the lubrication oil pressure will cause serious protection action.Due to structural reasons, the air-cooled compressor starts reducing crankcase pressure will be much slower, not very severe blistering, the bubble is difficult to enter the cylinder, air-cooled compressor so there is no problem with liquid starting fluid attack.In theory, the compressor crankcase heater installed (electric heater) can effectively prevent refrigerant migration. Short stop (eg at night), the crankcase heater to maintain power, the system can make the oil temperature is higher than other parts, refrigerant migration does not occur. No downtime (such as a winter), the heating oil before you start a few or ten hours, to evaporate the majority of oil in the refrigerant fluid can either start with a greatly reduced possibility of liquid strike , which also can reduce the harm caused by erosion of refrigerant. However, the actual application, the heater power to maintain after the shutdown or give ten hours before the heater power supply is difficult. Therefore, the practical effect of the crankcase heater will be greatly reduced.For larger systems, shut down before the evaporator to the compressor pumping liquidrefrigerant (known as taking the time to stop), can fundamentally prevent refrigerant migration. The pipe on the way back to the installation of gas-liquid separator, refrigerant migration can increase the resistance and reduce migration.Of course, by improving the compressor structure, can prevent refrigerant migration and reduce oil foaming degree. By improving the return-air-cooled compressor oil return path in the motor crankcase cavity and increased channel migration points (back pumps, etc.), you can cut off the access road after the shutdown, the refrigerant can not enter the crankshaft chamber; reduced intake Road and cross the channel to the crankcase when the crankcase pressure to slow down the boot speed, then control the degree of foaming and foam into the cylinder volume.(3) too much oilSemi-hermetic compressors usually have the oil sight glass to observe the oil level. Oil sight glass oil level above the range, indicating that the oil too much. Oil level is too high, high-speed rotation of the crankshaft and connecting rod may hit oil level frequently, causing a lot of splash oil. Once the oil splash fleeing into the inlet, into the cylinder, causing fluid to be hit.Large refrigeration system installation, they often need to add the appropriate lubricant. But for the poor oil return system, to seriously affect oil return to find the root causes of, and blindly added oil is dangerous. Even if the oil level being low, but also pay attention to sudden and large returns lubricating oil (such as after defrost) may cause danger. Attack caused by liquid lubricants are not uncommon.Compressor Failure Analysis (3) - lack of lubrication and lack of lubrication1. Lack of oilLack of oil is very easy to identify one of the compressor failure, compressor short of oil in the crankcase oil when little or no oil.Compressor is a special pump, a large number of refrigerant gas being discharged from the folder and also take a small portion of oil (known as Ben oil or an oil spill.) Ben compressor oil is inevitable, but Ben is different oils speed. Semi-sealed piston compressor discharge in about 2-3% of the oil, while the scroll compressor is 0.5-1%. For a displacement 100m3/hr, crankcase oil storage capacity of 6 liters of 6-cylinder compressor, 3% of the rush of oil means that about 0.3-0.8 liters / minute Ben oil, or running back to the oil-free compressor time for ten minutes.Discharge of the compressor oil does not return, the compressor will be short of oil. Compressor oil return in two ways, one is the oil separator oil return, the other is the return pipe back to the oil. Oil separator installed in the compressor discharge pipe on the road, generally isolated from 50-95% of the Ben oil, back to better effect, fast, greatly reducing the amount of oil into the system piping, which effectively extended the running time of no return oil . Particularly long cold storage refrigeration piping system, ice-making system and flooded the low temperature freeze-drying equipment, ten minutes after boot or even tens of minutes did not return very little fuel oil or return to the situation is not unusual, the design The system will not occur while the compressor low oil pressure shutdown problem. The installation of high efficiency cooling system can greatly extend the oil separator back to the oil-free compressor operation time, after the compressor start to ride back to the oilphase of the crisis-free.Separated from the oil will not enter the system, with the flow of refrigerant in the tube, the formation of the oil cycle. Lubricating oil into the evaporator, the temperature is low because of low solubility on the one hand, part of the oil separated from the refrigerant; the other hand, low temperature viscosity, separated from the oil easily attached to the pipe wall, flow is more difficult . Evaporating temperature is lower, back to the oil more difficult. This requires the evaporation of pipeline design and pipe way back to the design and construction must be conducive to return to the oil, a common practice is to use down-style pipeline design, and to ensure a larger flow rate. For particularly low temperature refrigeration systems, such as -85 ° C and -150 ° C cold chamber for medical, in addition to selection of efficient oil separator, but usually add special solvent to prevent blocking capillaries and expansion valve oil, and help return oil.Practice, the evaporator and back to the trachea caused by improper road design back to the oil problem is not rare. For the R22 and R404A systems, flooded evaporator back to the oil is very difficult to design the system return lines must be very careful. For such systems, the use of highly efficient oil pipeline can greatly reduce the amount of oil into the system, effectively extending the boot back to the pipe back to the oil-free time.When the compressor than the location of the evaporator is high, the vertical back to back on the oil pipe bending is required. Return bends to compact as much as possible to reduce the storage of oil. The spacing between the oil return to the right bend, bend back the amount of oil relatively long time, should add some oil.Load the system return lines must also be careful. When the load is reduced, the back will reduce the gas velocity, the speed is too low is not conducive to return oil. In order to ensure oil return under low load, the vertical double suction riser pipe can be used. Compressor oil return is not conducive to frequent starts. Continuous operation time is very short because the compressor stopped, and returned too late to form a stable tracheal high-speed air flow, oil can only stay in the pipeline. Return less than Ben oil, compressor will be short of oil. The shorter operation time, longer pipelines, more complex systems, back to the oil problem is more prominent. For the safety switch is not closed hydraulic compressor (including the scroll compressor and rotary compressor) and some semi-hermetic compressors), damage caused by frequent starting is more and more. Compressor maintenance is equally important. Defrost when the evaporator temperature increases, the oil viscosity decreases, easy flow. After the defrost cycle, refrigerant velocity, the oil will stay focused on return to the compressor. Therefore, the defrost cycle of the frequency and duration of each also need to be carefully set to avoid large fluctuations in oil or oil strike.Back when the refrigerant gas leakage of more speed will decrease, the speed is too low will cause oil pipe stuck in the back way, you can not quickly return to the compressor. Within the shell back to the compressor oil does not mean back to the crankcase. Crank chamber with the principle of negative pressure compressor oil return, if the piston due to wear caused by leaks, crankcase pressure rise, oil return check valve automatically closes the role of pressure difference, from the return pipe to return the oil to remain in motor chamber, unable to enter the crankcase, which is the return to the oil issue, the return of oil starvation will cause the same problem. In addition to wear such an incident。

关于化学材料的英语作文English: Chemistry plays a crucial role in the development and production of materials that are essential in our daily lives. From metals and ceramics to polymers and composites, chemical materials are used in a variety of industries such as construction, electronics, transportation, and healthcare. By understanding the chemical properties and behaviors of these materials, scientists and engineers can manipulate their structures to enhance their performance and durability. For example, the development of advanced materials like carbon nanotubes and graphene has revolutionized the fields of electronics and energy storage. Additionally, chemical materials are also crucial in the design of drug delivery systems, medical implants, and biomaterials for tissue engineering. Through ongoing research and innovations in the field of chemistry, we continue to discover new materials with unique properties and applications that have the potential to transform various industries and improve our quality of life.中文翻译: 化学在我们日常生活中必不可少的材料的开发和生产中扮演了至关重要的角色。

一水合二氧化氯湿法洗涤同时清除二氧化硫和一氧化氮1摘要本研究尝试在鼓泡反应器中通过氯化反应持续产生二氧化氯气体，并且利用它进一步清除废气中二氧化硫和氮的氧化物。

本实验是为了检测各种反应参数，例如输入二氧化硫含量、输入一氧化氮含量、反应介质的PH值、二氧化氯在二氧化硫的供给率和氮化物在45 ◦C的消耗率。

将一氧化氮氧化成二氧化氮，在洗气溶液中通入足量的二氧化氯气体。

在完全反应的条件下二氧化硫的消耗率大约是100%，氮氧化物的消耗率大约是66–72%。

氮氧化物的消耗率随着pH值的增大和一氧化氮含量的增加而稍有减少。

输入的二氧化硫的含量对二氧化氮的吸收有少量催化作用。

在洗涤液中通入过量的二氧化氯对氮氧化物的消耗率没有影响。

关键字：脱除；二氧化硫；一氧化氮；鼓泡反应；二氧化氯1．介绍化石燃料，即煤，石油和天然气是能源的主要原料。

根据韩国能量消耗监控公司（2002）的统计调查，石油、煤和天然气分别占韩国各种总能源来源的49.1, 23.5, 和 11.1%。

电厂、焚化炉、锅炉燃烧化石燃料，产生的废气中含二氧化硫和氮氧化物.燃烧这些能源的废气中主要含有一氧化氮和二氧化氮，但是氮氧化物的主要成分是一氧化氮（大约占90%）。

烟气脱硫是应用最广泛的有效地脱除二氧化硫的方法。

然而，一氧化氮就不像二氧化硫那么容易脱除了。

脱除氮氧化物的技术包括燃烧控制和燃烧后去除。

燃烧控制的目的是在矿物燃料燃烧时，减少氮氧化物的生成。

燃烧后去除包括选择性非催化还原，选择性催化还原，洗涤等。

在这些技术之中，洗刷的方法经济上是最具竞争力，与此同时能控制其他酸性气体和微粒物质[1]。

一般来说，添加剂加到洗涤系统中将一氧化氮转换成相对有惰性的二氧化氮，这可以由碱性吸收剂去除。

许多氧化剂的水溶液已经被研究证明能够有效地1论文出处及作业: Journal of Hazardous Materials, Dong-Seop Jin , Bal-Raj Deshwal , Young-Seong Park , Hyung-Keun Lee.脱除氮氧化物和亚氯酸钠。

化学专业英文作文范文英文：Chemistry is a fascinating subject that deals with the study of matter and its properties. As a chemistry major, I have learned about the different types of chemical reactions, the behavior of atoms and molecules, and the principles of chemical bonding. I have also gainedpractical experience in the laboratory, conducting experiments and analyzing data.One of the most interesting topics in chemistry is organic chemistry, which is the study of carbon-based compounds. It is a complex subject that requires a lot of memorization and understanding of various concepts, such as functional groups and reaction mechanisms. However, it is also a very rewarding subject because it helps us understand the chemistry of living organisms and the processes that occur in our bodies.Another aspect of chemistry that I find fascinating is the use of analytical techniques to identify and quantify substances. For example, spectroscopy is a powerful toolthat allows us to determine the structure of molecules and the presence of certain functional groups. Chromatographyis another technique that is commonly used to separate and analyze mixtures of compounds.Overall, chemistry is a challenging but rewardingsubject that has many practical applications in fields such as medicine, materials science, and environmental science.中文：化学是一门迷人的学科，涉及物质及其性质的研究。

化学的英语小作文Title: The Fascinating World of ChemistryIn the vast expanse of scientific disciplines, Chemistry stands as a towering pillar, weaving together the intricate tapestry of life's building blocks. It is a realm where matter transforms, energies dance, and the invisible becomes visible through the lens of scientific inquiry. As I delve deeper into this captivating world, I am struck by its boundless wonders and the profound impact it has on our daily lives.Chemistry, at its core, is the study of matter—its composition, structure, properties, and the changes it undergoes. It is the language that explains why water flows, fire burns, and metals shine. From the simplest of elements to the most complex of molecules, chemistry bridges the gap between the microscopic and the macroscopic, revealing the hidden harmonies within nature.One of the most fascinating aspects of chemistry is its ability to create and manipulate substances. In laboratories, scientists transform humble compounds into powerful medicines, clean energy sources, and advanced materials that shape our future. Think of the lifesaving drugs that combatdiseases, the polymers that make our clothes more durable, or the catalysts that clean up environmental pollutants. Each of these achievements is a testament to the ingenuity of chemical science.Moreover, chemistry is integral to understanding the workings of our bodies. It explains the biochemical reactions that fuel our cells, transmit signals in our brains, and maintain our health. Through the study of enzymes, hormones, and neurotransmitters, chemists gain insights into the intricacies of life itself, paving the way for breakthroughs in medical research and personalized medicine.Beyond its practical applications, chemistry also inspires awe and wonder. The vibrant hues of a sunset, the intricate patterns formed by crystals, and the explosive reactions in fireworks—all are manifestations of chemical magic. These phenomena remind us of the beauty and complexity inherent in the universe, and fuel our curiosity to explore further.In conclusion, the world of chemistry is a vast and fascinating landscape, filled with mysteries to uncover and challenges to overcome. It is a field that connects the past to the present and the present to the future, driving progress and improving the quality of life for all. As I continue my journey through this incredible realm, I am filled with a sense of wonderand gratitude for the gift of chemical knowledge that enriches our understanding of the world and ourselves.翻译：化学的迷人世界在浩瀚的科学领域中，化学犹如一座巍峨的支柱，编织着生命构成要素的复杂织锦。

化学专业文献翻译终结版通过国际教育联盟化学分子中光学胺酸组对有化対映体的手性羧酸进行的分析羧酸的纯对映体是一类重要的生物分子，手性药物和手性试剂等等。

对対映体的分析经常需要昂贵的仪器或者复杂的手性受体，然而，为了发展对对映体酸性的分析的简单而可信的方法是困难的。

在这篇文献中，2,3二苯甲酰酒石酸和苯基乙醇酸的-手性识别是第一个实施通过聚合诱导发射分子轴承光学纯胺酸集团，这是一种简单合成，这种手性识别不只是被肉眼所看见，还可以被氟光度计测量。

这两种対映体酸性的荧光强度的差异通过聚合体诱导发射分子598，这种手性识别可以被应用于对手性酸対映内容的定量分析。

1介绍羧酸纯的対映体是一种重要的生物分子，手性药物手性试剂等等。

传统的対映体的分析经常需要昂贵的仪器或者复杂的手性受体，也需要时间去实践，然而，为了发展对对映体酸性的分析的简单而可信的方法是困难的。

特别的，荧光受体可以区别两种手性羧酸対映体，可以在飞速的手性试验高产出药品发现和催化剂筛选提供一个真实的时间技巧。

然而，去设计和合成极好的手性荧光受体，对羧酸対映体仍然是个挑战。

近来，一种新的有机混合物以一种惊人的聚集诱导发光（AIE）或聚合体诱导发射增大（AIEE）被发现。

这些混合物还没有在固态形式上被抑制，因此，他们不仅仅在光电子材料上表现出一种潜能，同时也将对蛋白质、DNA、有机蒸汽、肝素、金属离子、氯以高度的选择性和稳定的荧光传感器，免疫分析和乃至自组装程序的叠层，等等。

虽然手性AIE混合物关系胆甾醇基团被报道称之为透明发光的金属，调查研究工作与手性识别相联系以AIE或者ＡＩＥＥ为基础的特性还没有被报道过。

它让我们想起新异的手性荧光受体可以被制得如果一个微小粒子持有ＡＩＥ特性和另一个微小粒子有手性识别能力相关联。

这里，我们第一个报道的是ＡＩＥ混合物关系光学纯的胺酸团可以enantioselectively集合导致用一个手性羧酸的有化対映体和大量的强度荧光差异直到超过２００倍，那一个可以在有化対映体组成品的定量分析中被应用。