英文文献及其翻译

合集下载

英文文献翻译

外文文献原稿和译文原稿Sodium Polyacrylate:Also known as super-absorbent or “SAP”(super absorbent polymer), Kimberly Clark used to call it SAM (super absorbent material). It is typically used in fine granular form (like table salt). It helps improve capacity for better retention in a disposable diaper, allowing the product to be thinner with improved performance and less usage of pine fluff pulp. The molecular structure of the polyacrylate has sodium carboxylate groups hanging off the main chain. When it comes in contact with water, the sodium detaches itself, leaving only carboxylions. Being negatively charged, these ions repel one another so that the polymer also has cross-links, which effectively leads to a three-dimensional structure. It has hige molecular weight of more than a million; thus, instead of getting dissolved, it solidifies into a gel. The Hydrogen in the water (H-O-H) is trapped by the acrylate due to the atomic bonds associated with the polarity forces between the atoms. Electrolytes in the liquid, such as salt minerals (urine contains 0.9% of minerals), reduce polarity, thereby affecting superabsorbent properties, especially with regard to the superabsorbent capacity for liquid retention. This is the main reason why diapers containing SAP should never be tested with plain water. Linear molecular configurations have less total capacity than non-linear molecules but, on the other hand, retention of liquid in a linear molecule is higher than in a non-linear molecule, due to improved polarity. For a list of SAP suppliers, please use this link: SAP, the superabsorbent can be designed to absorb higher amounts of liquids (with less retention) or very high retentions (but lower capacity). In addition, a surface cross linker can be added to the superabsorbent particle to help it move liquids while it is saturated. This helps avoid formation of "gel blocks", the phenomenon that describes the impossibility of moving liquids once a SAP particle gets saturated.History of Super Absorbent Polymer ChemistryUn til the 1980’s, water absorbing materials were cellulosic or fiber-based products. Choices were tissue paper, cotton, sponge, and fluff pulp. The water retention capacity of these types of materials is only 20 times their weight – at most.In the early 1960s, the United States Department of Agriculture (USDA) was conducting work on materials to improve water conservation in soils. They developed a resin based on the grafting of acrylonitrile polymer onto the backbone of starch molecules (i.e. starch-grafting). The hydrolyzed product of the hydrolysis of this starch-acrylonitrile co-polymer gave water absorption greater than 400 times its weight. Also, the gel did not release liquid water the way that fiber-based absorbents do.The polymer came to be known as “Super Slurper”.The USDA gave the technical know how several USA companies for further development of the basic technology. A wide range of grating combinations were attempted including work with acrylic acid, acrylamide and polyvinyl alcohol (PVA).Since Japanese companies were excluded by the USDA, they started independent research using starch, carboxy methyl cellulose (CMC), acrylic acid, polyvinyl alcohol (PVA) and isobutylene maleic anhydride (IMA).Early global participants in the development of super absorbent chemistry included Dow Chemical, Hercules, General Mills Chemical, DuPont, National Starch & Chemical, Enka (Akzo), Sanyo Chemical, Sumitomo Chemical, Kao, Nihon Starch and Japan Exlan.In the early 1970s, super absorbent polymer was used commercially for the first time –not for soil amendment applications as originally intended –but for disposable hygienic products. The first product markets were feminine sanitary napkins and adult incontinence products.In 1978, Park Davis (d.b.a. Professional Medical Products) used super absorbent polymers in sanitary napkins.Super absorbent polymer was first used in Europe in a baby diaper in 1982 when Schickendanz and Beghin-Say added the material to the absorbent core. Shortly thereafter, UniCharm introduced super absorbent baby diapers in Japan while Proctor & Gamble and Kimberly-Clark in the USA began to use the material.The development of super absorbent technology and performance has been largely led by demands in the disposable hygiene segment. Strides in absorption performance have allowed the development of the ultra-thin baby diaper which uses a fraction of the materials – particularly fluff pulp – which earlier disposable diapers consumed.Over the years, technology has progressed so that there is little if any starch-grafted super absorbent polymer used in disposable hygienic products. These super absorbents typically are cross-linked acrylic homo-polymers (usually Sodium neutralized).Super absorbents used in soil amendments applications tend to be cross-linked acrylic-acrylamide co-polymers (usually Potassium neutralized).Besides granular super absorbent polymers, ARCO Chemical developed a super absorbent fiber technology in the early 1990s. This technology was eventually sold to Camelot Absorbents. There are super absorbent fibers commercially available today. While significantly more expensive than the granular polymers, the super absorbent fibers offer technical advantages in certain niche markets including cable wrap, medical devices and food packaging.Sodium polyacrylate, also known as waterlock, is a polymer with the chemical formula [-CH2-CH(COONa)-]n widely used in consumer products. It has the ability to absorb as much as 200 to 300 times its mass in water. Acrylate polymers generally are considered to possess an anionic charge. While sodium neutralized polyacrylates are the most common form used in industry, there are also other salts available including potassium, lithium and ammonium.ApplicationsAcrylates and acrylic chemistry have a wide variety of industrial uses that include: ∙Sequestering agents in detergents. (By binding hard water elements such as calcium and magnesium, the surfactants in detergents work more efficiently.) ∙Thickening agents∙Coatings∙Fake snowSuper absorbent polymers. These cross-linked acrylic polymers are referred to as "Super Absorbents" and "Water Crystals", and are used in baby diapers. Copolymerversions are used in agriculture and other specialty absorbent applications. The origins of super absorbent polymer chemistry trace back to the early 1960s when the U.S. Department of Agriculture developed the first super absorbent polymer materials. This chemical is featured in the Maximum Absorbency Garment used by NASA.译文聚丙烯酸钠聚丙烯酸钠，又可以称为超级吸收剂或者又叫高吸水性树脂，凯博利克拉克教授曾经称它为SAM即：超级吸收性物质。

英文文献整篇翻译

英文文献整篇翻译Title: The Impact of Climate Change on BiodiversityClimate change is a pressing issue that has significant impacts on biodiversity worldwide. Changes in temperature, precipitation patterns, and extreme weather events are altering ecosystems and threatening the survival of many species. The loss of biodiversity not only affects the natural world but also has implications for human societies.One of the major impacts of climate change onbiodiversity is the shifting of habitats. As temperatures rise, many species are forced to move to higher latitudesor elevations in search of suitable conditions. This can disrupt ecosystems and lead to the decline or extinction of species that are unable to adapt to the new conditions.In addition to habitat loss, climate change is also causing changes in the timing of biological events such as flowering, migration, and reproduction. These changes can disrupt the delicate balance of ecosystems and lead to mismatches between species that depend on each other for survival.Furthermore, climate change is exacerbating otherthreats to biodiversity such as habitat destruction, pollution, and overexploitation. The combination of these factors is putting immense pressure on many species and pushing them closer to extinction.It is essential that we take action to mitigate the impacts of climate change on biodiversity. This includes reducing greenhouse gas emissions, protecting and restoring habitats, and implementing conservation measures to safeguard vulnerable species. By addressing the root causes of climate change and protecting biodiversity, we canensure a sustainable future for both the natural world and human societies.气候变化对生物多样性的影响气候变化是一个紧迫的问题，对全球的生物多样性产生重大影响。

外文文献及翻译

外文文献及翻译1. 文献："The Effects of Exercise on Mental Health"翻译：运动对心理健康的影响Abstract: This article explores the effects of exercise on mental health. The author discusses various studies that have been conducted on this topic, and presents evidence to support the claim that exercise can have positive impacts on mental well-being. The article also examines the mechanisms through which exercise affects mental health, such as the release of endorphins and the reduction of stress hormones. Overall, the author concludes that exercise is an effective strategy for improving mental health and recommends incorporating physical activity into daily routines.摘要：本文探讨了运动对心理健康的影响。

作者讨论了在这个主题上进行的各种研究，并提出证据支持运动对心理健康有积极影响的观点。

该文章还探讨了运动如何影响心理健康的机制，如内啡肽的释放和压力激素的减少。

总的来说，作者得出结论，运动是改善心理健康的有效策略，并建议将体育活动纳入日常生活。

2. 文献： "The Benefits of Bilingualism"翻译：双语能力的好处Abstract: This paper examines the benefits of bilingualism. The author presents research findings that demonstrate the cognitiveadvantages of being bilingual, such as enhanced problem-solving skills and improved attention control. The article also explores the social and cultural benefits of bilingualism, such as increased cultural awareness and the ability to communicate with people from different backgrounds. Additionally, the author discusses the positive effects of bilingualism on mental health, highlighting its role in delaying the onset of cognitive decline and in providing a buffer against age-related memory loss. Overall, the author concludes that bilingualism offers a range of advantages and recommends promoting bilingual education and language learning. 摘要：本文研究了双语能力的好处。

中英文文献以及翻译(化工类)

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）。

英文文献全文翻译

英文文献全文翻译全文共四篇示例，供读者参考第一篇示例：LeGuin, Ursula K. (December 18, 2002). "Dancing at the Edge of the World: Thoughts on Words, Women, Places".《世界边缘的舞蹈：关于语言、女性和地方的思考》Introduction:In "Dancing at the Edge of the World," Ursula K. LeGuin explores the intersection of language, women, and places. She writes about the power of words, the role of women in society, and the importance of our connection to the places we inhabit. Through a series of essays, LeGuin invites readers to think critically about these topics and consider how they shape our understanding of the world.Chapter 1: LanguageConclusion:第二篇示例：IntroductionEnglish literature translation is an important field in the study of language and culture. The translation of English literature involves not only the linguistic translation of words or sentences but also the transfer of cultural meaning and emotional resonance. This article will discuss the challenges and techniques of translating English literature, as well as the importance of preserving the original author's voice and style in the translated text.Challenges in translating English literature第三篇示例：Title: The Importance of Translation of Full English TextsTranslation plays a crucial role in bringing different languages and cultures together. More specifically, translating full English texts into different languages allows for access to valuable information and insights that may otherwise be inaccessible to those who do not speak English. In this article, we will explore the importance of translating full English texts and the benefits it brings.第四篇示例：Abstract: This article discusses the importance of translating English literature and the challenges translators face when putting together a full-text translation. It highlights the skills and knowledge needed to accurately convey the meaning and tone of the original text while preserving its cultural and literary nuances. Through a detailed analysis of the translation process, this article emphasizes the crucial role translators play in bridging the gap between languages and making English literature accessible to a global audience.IntroductionEnglish literature is a rich and diverse field encompassing a wide range of genres, styles, and themes. From classic works by Shakespeare and Dickens to contemporary novels by authors like J.K. Rowling and Philip Pullman, English literature offers something for everyone. However, for non-English speakers, accessing and understanding these works can be a challenge. This is where translation comes in.Translation is the process of rendering a text from one language into another, while striving to preserve the original meaning, tone, and style of the original work. Translating afull-length English text requires a deep understanding of both languages, as well as a keen awareness of the cultural andhistorical context in which the work was written. Additionally, translators must possess strong writing skills in order to convey the beauty and complexity of the original text in a new language.Challenges of Full-text TranslationTranslating a full-length English text poses several challenges for translators. One of the most significant challenges is capturing the nuances and subtleties of the original work. English literature is known for its rich and layered language, with intricate wordplay, metaphors, and symbolism that can be difficult to convey in another language. Translators must carefully consider each word and phrase in order to accurately convey the author's intended meaning.Another challenge of full-text translation is maintaining the author's unique voice and style. Each writer has a distinct way of expressing themselves, and a good translator must be able to replicate this voice in the translated text. This requires a deep understanding of the author's writing style, as well as the ability to adapt it to the conventions of the target language.Additionally, translators must be mindful of the cultural and historical context of the original work. English literature is deeply rooted in the history and traditions of the English-speaking world, and translators must be aware of these influences in orderto accurately convey the author's intended message. This requires thorough research and a nuanced understanding of the social, political, and economic factors that shaped the work.Skills and Knowledge RequiredTo successfully translate a full-length English text, translators must possess a wide range of skills and knowledge. First and foremost, translators must be fluent in both the source language (English) and the target language. This includes a strong grasp of grammar, syntax, and vocabulary in both languages, as well as an understanding of the cultural and historical context of the works being translated.Translators must also have a keen eye for detail and a meticulous approach to their work. Every word, sentence, and paragraph must be carefully considered and translated with precision in order to accurately convey the meaning of the original text. This requires strong analytical skills and a deep understanding of the nuances and complexities of language.Furthermore, translators must possess strong writing skills in order to craft a compelling and engaging translation. Translating a full-length English text is not simply a matter of substituting one word for another; it requires creativity, imagination, and a deep appreciation for the beauty of language. Translators mustbe able to capture the rhythm, cadence, and tone of the original work in their translation, while also adapting it to the conventions of the target language.ConclusionIn conclusion, translating a full-length English text is a complex and challenging task that requires a high level of skill, knowledge, and creativity. Translators must possess a deep understanding of both the source and target languages, as well as the cultural and historical context of the work being translated. Through their careful and meticulous work, translators play a crucial role in making English literature accessible to a global audience, bridging the gap between languages and cultures. By preserving the beauty and complexity of the original text in their translations, translators enrich our understanding of literature and bring the works of English authors to readers around the world.。

英文文献+翻译

Characterization of production of Paclitaxel and related Taxanes in Taxus Cuspidata Densiformis suspension cultures by LC,LC/MS, and LC/MS/MSCHAPTER THEREPLANT TISSUE CULTUREⅠ. Potential of Plant cell Culture for Taxane ProductionSeveral alternative sources of paclitaxel have been identified and are currently the subjects of considerable investigation worldwide. These include the total synthesis and biosynthesis of paclitaxel, the agriculture supply of taxoids from needles of Taxus species, hemisynthesis (the attachment of a side chain to biogenetic precursors of paclitaxel such as baccatin Ⅲ or 10-deacetylbaccatin Ⅲ), fungus production, and the production of taxoids by cell and tissue culture. This reciew will concentrate only on the latter possibility.Plant tissue culture is one approach under investigation to provide large amounts and a stable supply of this compound exhibiting antineoplastic activity. A process to produce paclitaxel or paclitaxel-like compounds in cell culture has already been parented. The development of fast growing cell lines capable of producing paclitaxel would not only solve the limitations in paclitaxel supplies presently needed for clinical use, but would also help conserve the large number of trees that need to be harvested in order to isolate it. Currently, scientists and researchers have been successful in initiating fast plant growth but with limited paclitaxel production or vice versa. Therefore, it is the objective of researchers to find a method that will promote fast plant growth and also produce a large amount of paclitaxel at the same time.Ⅱ. Factors Influencing Growth Paclitaxel ContentA.Choice of Media for GrowthGamborg's (B5) and Murashige & Skoog's (MS) media seem to be superior for callus growth compared to White's (WP) medium. The major difference between these two media is that the MS medium contains 40 mM nitrate and 20mM ammonium, compared to 25mM nitrate and 2mM ammonium. Many researchers have selected the B5 medium over the MS medium for all subsequent studies, although they achieve similar results.Gamborg's B5 media was used throughout our experiments for initiation of callus cultures and suspension cultures due to successful published results. It was supplemented with 2% sucrose, 2 g/L casein hydrolysate, 2.4 mg/L picloram, and 1.8 mg/L α-naphthalene acetic acid. Agar (8 g/L) was used for solid cultures.B. Initiation of Callus CulturesPrevious work indicated that bark explants seem to be the most useful for establishing callus. The age of the tree did not appear to affect the ability to initiate callus when comparing both young and old tree materials grown on Gamborg's B5 medium supplemented with 1-2 mg/L of 2,4-dichlorophenoxyacetic acid. Callus cultures initiated and maintained in total darkness were generally pale-yellow to light brown in color. This resulted in sufficient masses of friable callus necessary for subculture within 3-4 weeks. However, the growth rate can decline substantially following the initial subculture and result in very slow-growing, brown-colored clumps of callus. It has been presumed that these brown-colored exudates are phenolic in nature and can eventually lead to cell death. This common phenomenon is totally random and unpredictable. Once this phenomenon has been triggered, the cells could not be saved by placing them in fresh media. However, adding polyvinylpyrrolidone to the culture media can help keep the cells alive and growing. Our experience with callus initiationwas similar to those studies.Our studies have found that callus which initiated early (usually within 2 weeks ) frequently did not proliferate when subcultured and turned brown and necrotic. In contrast, calli which developed from 4 weeks to 4 months after explants were fist placed on initiation media were able to be continuously subcultured when transferred at 1-2 month intervals. The presence of the survival of callus after subsequent subculturing. The relationship between paclitaxel concentration and callus initiation, however, has not been clarified.C. Effect of SugarSucrose is the preferred carbon source for growth in plant cell cultures, although the presence of more rapidly metabolized sugar such as glucose favors fast growth. Other sugars such as lactose, galactose, glucose, and fructose also support cell growth to some extent. On the other hand, sugar alcohols such as mannitol and sorbital which are generally used to raise the sugars added play a major role in the production of paclitaxel. In general, raising the initial sugar levels lead to an increase of secondary metabolite production. High initial levels of sugar increase the osmotic potential, although the role of osmotic pressure on the synthesis of secondary metabolites is not cleat. Kim and colleagues have shown that the highest level of paclitaxel was obtained with fructosel. The optimum concentration of each sugar for paclitaxel production was found to be the same at 6% in all cases. Wickremesinhe and Arteca have provided additional support that fructose is the most effective for paclitaxel production. However, other combinations of sugars such as sucrose combined with glucose also increased paclitaxel production.The presence of extracellular invertase activity and rapid extracellular sucrose hydrolysis has been observed in many cell cultures. These reports suggest that cells secrete or possess on their surface excess amounts of invertase, which result in the hydrolysis of sucrose at a much faster rate. The hydrolysis of sucrose coupled with the rapid utilization of fructose in the medium during the latter period of cell growth. This period of increased fructose availability coincided with the faster growth phase of the cells.D. Effect of Picloram and Methyl JasmonatePicloram (4-amino-3.5.6-trichloropicolinic acid) increases growth rate while methyl jasmonate has been reported to be an effective elicitor in the production of paclitaxel and other taxanes. However, little is known about the mechanisms or pathways that stimulate these secondary metabolites.Picloram had been used by Furmanowa and co-workers and Ketchum and Gibson but no details on the effect of picloram on growth rates were given. Furmanowa and hid colleagues observed growth of callus both in the presence and absence of light. The callus grew best in the dark showing a 9.3 fold increase, whereas there was only a 2-4 fold increase in the presence of light. Without picloram, callus growth was 0.9 fold. Unfortunately,this auxin had no effect on taxane production and the high callus growth rate was very unstable.Jasmonates exhibit various morphological and physiological activities when applied exogenously to plants. They induce transcriptional activation of genes involved in the formation of secondary metabolites. Methyl jasmonate was shown to stimulate paclitaxel and cephalomannine (taxane derivative) production in callus and suspension cultures. However, taxane production was best with White's medium compared to Gamborg's B5 medium. This may be due to the reduced concentration of potassium nitrate and a lack of ammonium sulfate with White's medium.E. Effect of Copper Sulfate and Mercuric ChlorideMetal ions have shown to play significant roles in altering the expression of secondary metabolic pathways in plant cell culture. Secondary metabolites,such as furano-terpenes, have been production by treatment of sweet potato root tissue with mercuric chloride. The results for copper sulfate, however, have not been reported. F. Growth Kinetics and Paclitaxel ProductionLow yields of paclitaxel may be attributed to the kinetics of taxane production that is not fully understood. Many reports stated inconclusive results on the kinetics of taxane production. More studies are needed in order to quantitate the taxane production. According to Nett-Fetto, the maximum instantaneous rate of paclitaxel production occurred at the third week upon further incubation. The paclitaxel level either declined or was not expected to increase upon further incubation. Paclitaxel production was very sensitive to slight variations in culture conditions. Due to this sensitivity, cell maintenance conditions, especially initial cell density, length of subculture interval, and temperature must be maintained as possible.Recently, Byun and co-workers have made a very detailed study on the kinetics of cell growth and taxane production. In their investigation, it was observed that the highest cell weight occurred at day 7 after inoculation. Similarly, the maximum concentration for 10-deacetyl baccatin Ⅲ and baccatin Ⅲ were detected at days 5 and 7, respectively. This result indicated that they are metabolic intermediates of paclitaxel. However, paclitaxel's maximum concentration was detected at day 22 but gradually declined. Byun and his colleagues suggested that paxlitaxel could be a metabolic intermediate like 10-deacetyl baccatin Ⅲ and baccatin Ⅲ or that pacliltaxel could be decomposed due to cellular morphological changes or DNA degradation characteristic of cell death.Pedtchanker's group also studied the kinetics of paclitaxel production by comparing the suspension cultures in shake flasks and Wilson-type reactors where bubbled air provided agitation and mixing. It was concluded that these cultures of Taxus cuspidata produced high levels of paclitaxel within three weeks (1.1 mg/L per day ). It was also determined that both cultures of the shake flask and Wilson-type reactor produced similar paclitaxel content. However, the Wilson-type reactor had a more rapid uptake of the nutrients (i.e. sugars, phosphate, calcium, and nitrate). This was probably due to the presence of the growth ring in the Wilson reactor. Therefor, the growth rate for the cultures from the Wilson reactor was only 135 mg./L while the shake flasks grew to 310 mg/L in three weeks.In retrospect, strictly controlled culture conditions are essential to consistent production and yield. Slight alterations in media formulations can have significant effects upon the physiology of cells, thereby affecting growth and product formation. All of the manipulations that affect growth and production of plant cells must be carefully integrated and controlled in order to maintain cell viability and stability.利用LC,LC/MS和LC/MS/MS悬浮培养生产紫杉醇及邓西佛米斯红豆杉中相关紫杉醇类的特征描述第三章植物组织培养Ⅰ.利用植物细胞培养生产紫杉的可能性紫杉醇的几个备选的来源已被确定，而且目前是全球大量调查的主题。

英文文献原文及对应翻译

Adsorption char acter istics of copper , lead, zinc and cadmium ions by tourmaline(环境科学学报英文版) 电气石对铜、铅、锌、镉离子的吸附特性JIANG Kan1,*, SUN Tie-heng1,2 , SUN Li-na2, LI Hai-bo2(1. School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. jiangkan522@; 2. Key Laboratory of Environmental Engineering of Shenyang University, Shenyang 110041, China)摘要：本文研究了电气石对Cu2+、Pb2+、Zn2+和Cd2+的吸附特性，建立了吸附平衡方程。

研究四种金属离子的吸附等温线以及朗缪尔方程。

结果表明电气石能有效地去除水溶液中的重金属且具有选择性：Pb2+> Cu2+> Cd2+> Zn2+。

电气石对金属离子吸附量随着介质中金属离子的初始浓度的增加而增加。

电气石也可以增加金属溶液的pH值；发现电气石对Cu2+、Pb2+、Zn2+和Cd2+的最大吸附量为78.86、154.08、67.25和66.67mg/g；温度在25-55℃对电气石的吸附量影响很小。

此外研究了Cu2+、Pb2+、Zn2+和Cd2+的竞争吸附。

同时观察到电气石对单一金属离子的吸附能力为Pb>Cu>Zn>Cd，在两种金属系统中抑制支配地位是Pb>Cu，Pb>Zn，Pb>Cd，Cu>Zn，Cu>Cd，和Cd>Zn。

关键字：吸附；重金属含量；朗缪尔等温线；电气石介绍重金属是来自不同行业排出的废水，如电镀，金属表面处理，纺织，蓄电池，矿山，陶瓷，玻璃。

英文文献及翻译

英文文献及翻译ABSTRACTAn impact crusher with a rotor and one or more impact members interconnected to form an adjustable impact member system，a first impact member being mounted pivotally around a first horizontal axis by way of at least one drive means，on the second horizontal axis of which a further impact member，pivotal by way of at least one drive means，is provided，in which context the horizontal axis pivotally supporting the impact member is provided in the region of that end of the first impact member which is remote from the horizontal axis and the second impact member comprises one or more levers.IMPACT CRUSHERFIELD OF THE INVENTIONOur present invention relates to an impact crusher of the type in which a rotor is Provided with crushing elements which cooperate with impact members which cooperate to form a crushing gap and to an impact member assembly suitable for use with such a rotor. Moro Particularly the invention relates to an impact crusher comprising a rotor and two or more impact members interconnected to form an adjustable impact member system，a first impact member being mounted pivotally around a first horizontal axis by way of at least one drive means，and having a second horizontal axis on which a second impact member，pivotal by way of at least one drive means，15 provided.BACKGROUND OF THE INVENTIONAn impact crusher for crushing material of variousconsistencies is known for example from DE 23 31 729 Al in which the impact plates are interconnected in articulated manner to form a coherent composite pivotal impact member，each of the interconnected impact plates deriving adjustable support individually from the housing. The impact plates may have impact surfaces which are at angles to one another or arc stepped along the path of the material as it 15 entrained from the inlet side of the machine.The principles of such machines have also been developed in the Chemical Engineers Handbook，Perry and Chilton，5th edition，McGraw Hill Book Company，New York，1973，at Chapters，pages 19 ff.This known impact crusher，just like impact other crushers of the same genus，suffers from the substantial drawback that the upper impact member，provided downstream of the machine inlet yields outwardly due to foreign objects which cannot be crushed entering the machine，so that the crushing gap between the rotor and the lower impact member is decreased to such an extent，due to the upper impact member pivoting outwardly，that a risk arises of foreign objects getting wedged between the rotor and the impact member,leading to possible damage to the rotor and/or the impact member，so that the continued operability of the installation can no longer be ensured.OBJECTS OF THE INVENTIONIt is the principal object of the present invention to provide an improved impact crusher such that the damage which can be caused by the entry of a noncrushable foreign object can be minimized. Another object of the invention is to provide an improved impact crusher which is free from the drawbacks ofearlier devices or apparatuses of this type and particularly the drawbacks mentioned above.Still another object of this invention is to provide improved impact assembly for a rotor-type crusher or breaker whereby drawbacks which could have resulted in down time can be avoided.SUMMARY OF THE INVENTIONThese objects are attained，in accordance with the invention in an impact crusher of the type in which a rotor and two or more impact members are provided along the path of the crusher members of the rotor to form an adjustable impact assembly. A first impact member is pivotally mounted at a firsthorizontal axis and a second impact member is pivotally mounted on the first impact member by a second horizontal．axis and respective drive means is provided for controlling the displacement of the impact members．According to the invention，the horizontal axis pivotally supporting the second impact member is provided in the 5 region of that end of the first impact member which is remote from the first horizontal axis and the second impact member comprises one or more levers．It is an important feature of the invention that due to the specific arrangement of the point of engagement for the 10 support and the point of articulation of the lower impact member to the lever，the crushing gap between the lower impact member and the rotor is enlarged in the event of the upper impact member yielding due to foreign object interference．Because of the geometrical relationships with regard to the cylinder hinge point and the axes of the impact members，theedge of the lower impact member closest to the rotor is moved automatically in such a manner during opening of the impact member, for which purpose a housing member is 20swibeled around the pivotal axis，that the edge does not collide with the rotor or the beater bars，thus preventing damage．Different drive means，preferably hydraulic cylinders，25 may be emp10yed in Order to adjust the two impact members．More particularly，the impact crusher can comprise:a housing; an impact crusher rotor rotatable in the housing about a horizontal rotor axis; and at least one impact member assembly in the housing adjustable relative to the rotor，the assembly including: a first impact member having impact surfaces juxtaposed with the rotor and pivotally mounted in the housing for movement about a first horizontal pivot axis to shift the surfaces toward and away from the rotor，a first drive means articulated to the first impact member for angularly displacing the first impact member about the first horizontal pivot axis，a second impact member having impact surfaces juxtaposed with the rotor and pivotally mounted in the housing for movement about a second horizontal pivot axis on the first impact member at a location remote from the first horizontal pivot axis to shift the surfaces of the second impact member toward and away from the rotor，at least one lever swingable about the second horizontal pivot axis and operatively connected with the second impact member for pivotally displacing same about the second horizontal pivot axis，and second drive means articulated to the lever for angularly displacing the second impact member about the second horizontal pivot axis．The impact crusher according to the invention is characterized by a particularly high operational reliability and，therefore，a particularly long useful life due to the advantageous arrangement of the point of engagement for the support of the lower impact member．BRIEF DESCRIPTION OF THE DRAWINGThe above and other objects，features，and advantages will become more readily apparent from the following description，reference being made to the accompanying drawing in which: FIG.1 is a diagrammatic transverse section through an impact crusher according to the invention; 5,890,666；FIG.IA is the impact crusher of FIG.1，shown with pivotal housing in open position；FIG.2 is a section taken along the line 2-2 of FIG.1；FIG.3 is a detail view of the connection of the levers with extensions of the second impact member．SPECIFIC DESCRIPTIONThe impact crusher illustrated in FIG.1 comprises a housing member 9 adapted to swing openaround a pivotalaxis 8 in order to open the impact crusher，and includes a rotor 10 adapted to be rotationally-driven，equipped with crushing elements，not shown in the drawing. Two impact members 1 and4，equipped with a multitude of impact elements 11 are provided in a manner facing the rotor 10．The impact member 1 disposed above the impact member 4，is pivotally mounted around a horizontal axis 2 by way of at least one cylinder 3 or a different drive element engaging in a hinge point 3a.Ai an end of the impact members in the region remote from the axis2，i.e. at a lower end，a further horizontal axis 6 is provided for pivotally mounting the impact member 4.The gap between the impact members l，4 and the rotor 10 can be denoted as crushing chute. The impact member 4comprises one or more levers 4a on which one or a plurality of cylinders 5 or other drive elements engages/engage at the associated hinge point 5a. The crushing gap 7 is formed by the impact member 4 and the rotor 10．The material to be crushed，reaching the impact crusher in the direction of the arrow 22，is pre-crushed in the upper region of the crusher and is further crushed by the upper impact member l，being finally crushed to the pre-set particle size by the lower impact member 4 in the crushing gap 7．From FIG.2，it will be apparent that two hydraulic cylinder drivers 5 are provided on each side of the impact member 1 and are connected to respective levers 4a and from FIG.3 it can be seen that each lever 4a which is rigid with the member 4 is on an extension 4b of that impact member to the respective side of the impact member 1．The impact surfaces of the impact members 1 and 4 are provided at 12 and 13 on the impact members and the pivot axis 8 for the housing part 9 carrying the axis 2 is so arranged with respect to the articulation points 5a and the axis 6 that，when the housing part 9 is swung open in the counterclockwise direction and the drives 3 and 5 are correspondingly actuated，there will be no collision between the impact members 1 and 4 and the rotor 10 or the crushing elements thereon．We claim：1．An impact crusher comprising: a housing; an impact crusher rotor rotatable in said housing about a horizontal rotor axis; and at least one impact member assembly in said housing adjustable relative to said rotor，said assembly including: a first impact member having impact surfaces juxta posed with said rotor and pivotally mounted in said housing for movement about a first horizontal pivot axis to shift said surfaces toward and awayfrom said rotor，a first drive means articulated to said first impact member for angularly displacing said first impact member about said first horizontal pivot axis，a second impact member having impact surfaces juxtaposed with said rotor and pivotally mounted in said housing for movement about a second horizontal pivot axis on said first impact member at a location remote from said first horizontal pivot axis to shift said surfaces of said second impact member toward and away from said rotor，lever means swingable about said second horizontal pivot axis and operatively connected with said second impact member for pivotally displacing same about said second horizontal pivot axis，and second drive means articulated to said lever for angularly displacing said second impact member about said second horizontal pivot axis，said lever means comprising a respective lever formed on said second impact member on extensions thereof along said 20 second horizontal pivot axis on opposite sides of said first impact member，each of said levers being pivotally connected with a respective second drive means at a respective articulation point．2．The impact crusher defined in claim 1 wherein said hinge points and said second horizontal axis being so located 25 so that，upon movement of said first impact member away from said rotor，a gap between said second impact member and said rotor increases．3．The impact crusher defined in claim 1 wherein said housing includes a movable housing part pivotally connected to a stationary housing part for opening of said crusher and said first axis is providedon said movable housing part．4．The impact crusher defined in claim 1 wherein saidhousing includes a movable housing part pivotally connected to a stationary housing part for opening of said crusher and said first horizontal axis is provided on said movable housing part，said points of articulation and Said second horizontal pivot axis being arranged relative to a pivot axis of movable horizontal Dart that collision between said second impact member with said rotor is precluded during opening of said crusher by swinging of said movable housing part．5．An impact assembly for an impact crusher having a rotor rotatable in a housing about a horizontal rotor axis，Said impact assembly cooperating with said rotor to form an adjustable crushing gap，said impact assembly including: a first impact member having impact surfaces juxtaposed with said rotor and pivotally mounted in said housing for movement about a first horizontal pivot axis to shift said surfaces toward and away from said rotor，a first drive means articulated to said first impact member for angularly displacing said first impact member about said first horizontal pivot axis，a second impact member having impact surfaces juxtaposed with said rotor and pivotally mounted in said housing for movement about a second horizontal pivot axis on said first impact member at a location remote from said first horizontal pivot axis to shift said surfaces of said second impact member toward and away from said rotor，lever means swingable about said second horizontal pivot axis and operatively connected with said second impact member for pivotally displacing same about said second horizontal pivot axis，and second drive means articulated to said lever for angularly displacing said second impact member about said second horizontal pivot axis，said lever means comprising a respectiVe lever formed on said second impact member on extensionsthereof along said second horizontal pivot axis on opposite sides of said first impact member，each of said levers being pivotally connected with a respective second drive means at a respective articulation point．6．The impact assembly defined in claim 5 wherein said hinge points and said second horizontal axis are located so that，upon movement of said first impact member away from said rotor，a gap between said second impact member and said rotor increases．摘要一个带有转子的撞击破碎单元还有一个或更多破碎单元互相连接而形成一个比较完整的破碎系统，一个第一个破碎单元通过至少一种调节方式很好的绕第一个水平轴线旋转，在第二水平轴线处另外一个破碎单元通过至少一种调节方式进行绕轴线旋转，这两种方式是通过支持碰撞构材的水平轴线来提供的，在第一个破碎单元的末端的区域内与水平桥线还有第二个破碎单元像个很大的距离。

英文文献小短文(原文加汉语翻译)

A fern that hyperaccumulates arsenic(这是题目，百度一下就能找到原文好，原文还有表格，我没有翻译)A hardy, versatile, fast-growing plant helps to remove arsenic from contaminated soilsContamination of soils with arsenic,which is both toxic and carcinogenic, is widespread1. We have discovered that the fern Pteris vittata (brake fern) is extremely efficient in extracting arsenic from soils and translocating it into its above-ground biomass. This plant —which, to our knowledge, is the first known arsenic hyperaccumulator as well as the first fern found to function as a hyperaccumulator— has many attributes that recommend it for use in the remediation of arsenic-contaminated soils.We found brake fern growing on a site in Central Florida contaminated with chromated copper arsenate (Fig. 1a). We analysed the fronds of plants growing at the site for total arsenic by graphite furnace atomic absorption spectroscopy. Of 14 plant species studied, only brake fern contained large amounts of arsenic (As;3,280–4,980 We collected additional samples of the plant and soil from the contaminated site –1,603 As) and from an uncontaminated site –As). Brake fern extracted arsenic efficiently from these soils into its fronds: plantsgrowing in the contaminated site contained 1,442–7,526 Arsenic and those from the uncontaminated site contained –These values are much higher than those typical for plants growing in normal soil, which contain less than of arsenic3.As well as being tolerant of soils containing as much as 1,500 arsenic, brake fern can take up large amounts of arsenic into its fronds in a short time (Table 1). Arsenic concentration in fern fronds growing in soil spiked with 1,500 Arsenic increased from to 15,861 in two weeks. Furthermore, in the same period, ferns growing in soil containing just 6 arsenic accumulated 755 Of arsenic in their fronds, a 126-fold enrichment. Arsenic concentrations in brake fernroots were less than 303 whereas those in the fronds reached 7,234 of 100 Arsenic significantly stimulated fern growth, resulting in a 40% increase in biomass compared with the control (data not shown).After 20 weeks of growth, the plant was extracted using a solution of 1:1 methanol:water to speciate arsenic with high-performance liquid chromatography–inductively coupled plasma mass spectrometry. Almost all arsenic was present as relatively toxic inorganic forms, with little detectable organoarsenic species4. The concentration of As(III) was greater in the fronds (47–80%) than in the roots %), indicating that As(V)was converted to As(III) during translocation from roots to fronds.As well as removing arsenic from soils containing different concentrations of arsenic (Table 1), brake fern also removed arsenic from soils containing different arsenic species (Fig. 1c). Again, up to 93% of the arsenic was concentrated in the fronds. Although both FeAsO4 and AlAsO4 are relatively insoluble in soils1, brake fern hyperaccumulated arsenic derived from these compounds into its fronds (136–315 levels 3–6 times greater than soil arsenic.Brake fern is mesophytic and is widely cultivated and naturalized in many areas with a mild climate. In the United States, it grows in the southeast and in southern California5. The fern is versatile and hardy, and prefers sunny (unusual for a fern) and alkaline environments (where arsenic is more available). It has considerable biomass, and is fast growing, easy to propagate,and perennial.We believe this is the first report of significant arsenic hyperaccumulation by an unmanipulated plant. Brake fern has great potential to remediate arsenic-contaminated soils cheaply and could also aid studies of arsenic uptake, translocation, speciation, distribution anddetoxification in plants.*Soil and Water Science Department, University ofFlorida, Gainesville, Florida 32611-0290, USAe-mail†Cooperative Extension Service, University ofGeorgia, Terrell County, PO Box 271, Dawson,Georgia 31742, USA‡Department of Chemistry & SoutheastEnvironmental Research Center, FloridaInternational University, Miami, Florida 33199,1. Nriagu, J. O. (ed.) Arsenic in the Environment Part 1: Cycling and Characterization (Wiley, New York, 1994).2. Brooks, R. R. (ed.) Plants that Hyperaccumulate Heavy Metals (Cambridge Univ. Press, 1998).3. Kabata-Pendias, A. & Pendias, H. in Trace Elements in Soils and Plants 203–209 (CRC, Boca Raton, 1991).4. Koch, I., Wang, L., Ollson, C. A., Cullen, W. R. & Reimer, K. J. Envir. Sci. Technol. 34, 22–26 (2000).5. Jones, D. L. Encyclopaedia of Ferns (Lothian, Melbourne, 1987).积累砷的蕨类植物耐寒，多功能，生长快速的植物，有助于从污染土壤去除砷有毒和致癌的土壤砷污染是非常广泛的。

英文文献及翻译(计算机专业)

英文文献及翻译(计算机专业)The increasing complexity of design resources in a net-based collaborative XXX common systems。

design resources can be organized in n with design activities。

A task is formed by a set of activities and resources linked by logical ns。

XXX managementof all design resources and activities via a Task Management System (TMS)。

which is designed to break down tasks and assign resources to task nodes。

This XXX。

2 Task Management System (TMS)TMS is a system designed to manage the tasks and resources involved in a design project。

It poses tasks into smaller subtasks。

XXX management of all design resources and activities。

TMS assigns resources to task nodes。

XXX。

3 Collaborative DesignCollaborative design is a process that XXX a common goal。

In a net-based collaborative design environment。

n XXX n for all design resources and activities。

外文文献及翻译

外文文献（一）原文DUAL FULL BRIDGE PROTECTED MOTOR DRIVER（A3976）The A3976 is designed to drive both windings of a bipolar stepper motor or bidirectionally control two DC Motors. Both H-Bridges are capable of continuous output currents of up to+/- 500 mA and operating voltages to 30V. Free wheeling, substrate isolated diodes are included for output transient suppression when switching motors or other inductive loads. For each bridge the PHASE input controls load current polarity by selecting the appropriate source and sink driver pair. The ENABLE input, when held high, enables the respective output H-bridge. When both ENABLE pins are held low the device will enter SLEEP mode and consume less than 100mA. The 3976 is protected to ensure safe operation in harsh operating environments and was designed specifically for automotive applications. Protection circuitry will check for open or shorted load, motor lead short to ground or supply, VBB overvoltage, VCC undervoltage, and thermal shutdown. If any of these conditions are detected the outputs will be disabled and fault information will be output to diagnostic pins FAULT1 and FAULT2. The 3976 is supplied in a choice of two power packages, a 16-lead plastic DIP with a copper batwing tab (suffix ‘B’), and a 24-lead plastic SOIC with a copper batwing tab (suffix ‘LB’). In both cases, the power tab is at ground potential and needs no electrical isolation.FEATURES（1）30 V , ±500 mA Continuous Output Rating（2）35V Load Dump Survival（3）Output Short Circuit Protection（4）Coded Fault Diagnostic Outputs（5）Low Current Standby Mode（6）Open Load Monitor（7）Low Current Standby Mode（8）VBB Over Voltage Shutdown（9）Internal Thermal Shutdown Circuitry（10）Internal Low Parasitic Free Wheeling Diodes（11）Crossover Current ProtectionABSOLUTE MAXIMUM RATINGSat TA = +25°COperating Supply Voltage, VBB .................... 30 VNon-Operating Supply Voltage..................... 35 V Output Current, IOUT ............................±500 mA* Logic Supply Voltage, VCC.......................... 7.0 V Fault Output Voltage ................................... 7.0 VLogic Input Voltage Range, VIN.......................... -0.3 V to VCC + 0.3 VPackage Power Dissipation (TA = +25°C), PDA3976KLB..................................2.2 WA3976KB ....................................2.9 WOperating Temperature Range,TA ..............................-40°C to +125°CJunction Temperature, TJ .........................+150°C Storage Temperature Range, TS...............................-55°C to +150°C* Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current rating or ajunction temperature of 150°C.PART NUMBER PACKAGE RØJA RØJTA3976KLB24 Lead SOIC56︒C/W6︒C/WA3973KB16 Lead DIP43︒C/W6︒C/WInput LogicPHASE ENABLE OUTA OUTBX 0 OFF OFF0 1 LOW HIGH1 1 HIGH LOWFault LogicFault Condition FAULT1FAULT2Thermal Shutdown LOW LOWShort to Battery or Open Load LOW HIGHShort to Ground HIGH LOWNormal Operation HIGH HIGHAPPLICATION NOTESOpen Lead Protection. During normal PWM operation diagnostic circuitry will look for a minimum source current level after a bridge is signalled on. Additionally, the diode flyback is monitored on the proper output. The logic will signal a fault and disable the outputs if it determines that the current is below the minimum level AND no flyback is occurring. If the inductive load is too large, the current would take too long to reach the minimal level and afalse open load would be reported. It is recommended that the inductive load be less than38mH.Short Circuit Protection. Internal sense resistors in series with VBB and ground willtrip the fault circuitry if greater than 1.1A is detected. To prevent false overcurrent events due to reverse recovery spikes of the clamp diodes, the current monitor is blanked for 5us after a high side is signalled to turn on. If an additional input command follows after the initial fault, the selected pair of drivers will pulse on for the 5us blanking duration. The short circuit fault will remember the input state where the fault occurred and will wait for that particular logic state after the short has been removed before normal operation is allowed to resume.Thermal Protection. Circuitry turns OFF all drivers when the junction temperaturereaches 170°C typically. It is intended only to protect the device from failures due to excessive junction temperatures and has a hysteresis of approximately 15°C.Layout. The printed wiring board should use a heavy ground plane. For optimum electricaland thermal performance, the driver should be soldered directly onto the board. The load supply pin, VBB, should be decoupled with an electrolytic capacitor (> 47 μF is recommended) placed as close to the device as possibleEnengy or Solar EnegryEnergy means the power which does work and drives machines. All living things (including humans) rely on the sun as a source of energy. Coal, petroleum, and natural gas are energy sources available today because organisms in the past captured sunlight energy and stored it in the complex organic molecules that made up their bodies, which were then compressed and concentrated. With the development of society, a large of energy sources have been used,such as coal, petroleum, natural gas, geothermal energy, nuclear fission power, nuclear fusion power, solar energy, and Hydrogen gas. however, under the circumstances, the quantity of energy source is limited. unlimited usage of energy source results in energy crisis. At present, most of the energy consumed by humans is produced from fossil fuels. The greatest recoverable fossil is in the form of coal and lignite. Although world coal resources are enomous and potentially can fill energy needs for a century or two, their utilization is limited by environmental disruption from mining and emissions of carbon dioxide and sulfur dioxide. These would become intolerable long before coal resources were exhausted. Only a small percentage of coal and lignite has been utilized to date, whereas much of the recoverable petroleum and natural gas has already been consumed. Petroleum has several characteristics that make it superior to coal as a source of energy. Its extraction causes less environmental damage than does coal mining. It is a more concentrated source of energy than coal, and it burns with less pollution, and it can be moved easily through pipes. These characteristics make it an ideal fuel for automobiles.Since first commercial oil well in 1859, somewhat more than 100 million barrels of oil have been produced in the United States, most of it in recent years. In 1990 world petroleumconsumption was at a rate of about 65 million barrels per day. Projected use of petroleum and natural gas indicates rapid depletion. Alaskan oil can help the petroleum supply only temporarily. Peak world petroleum resources production will be reached within a few years. Since the first "energy crisis" of 1973-1974, some concrete actions have even taken place. However, the several-fold increase in crude oil prices since 1973 has extacted a toll. In the U.S. and other industrialized nations, the economy has been plagued by inflation, recession, unemployment, and obsolescence of industrial equipment. The economies of some petroleum-deficient developing countries have been devastated by energy prices.Energy crisis was accompanied by worldwide shortages of some foods and minerals, followed in some cases by surpluses, such as the surplus wheat resulting from increased planting and a copper surplus resulting from the efforts of copper-producing nations to acpuire foreign currency by copper export.As known to all,the availability and cost of energy has become dominant factors in society today. Obviously, solving the "energy crisis" makes good sense. Many schemes has been proposed for conserving present energy resources and for developing new ones. It is always possible to use less energy in any process. Therefore, energy engineer is created and developed. The first goal of energy engineer is to determine the methods by which energy utilization is reduced but the output remains the same, or even increases.The second goal is to determine which methods of using less energy are cost effective.Conventional engineering techniques are used to evaluated the mechanisms of energy use. Economic considerations are of equal importance and life cycle cost and saving techniques are used to determine cost-effective measures. The evaluation focuses on those uses which are significant in the overall picture and attempts to determine those technical measures that can reduce usage and save money.Meanwhile, looking for ideal energy sources is also very important to solve energy crisis. The recipe for an ideal energy source calls for one that is unlimited in supply, widely available, and inexpensive; it should not add to the earth's total heat burden or produce chemical air and water pollutants. Solar energy fulfills all of these criteria. Solar energy does not add excess heat to that which must be radiated from the earth. On a global basis, utilization of only a small fraction of solar energy reaching the earth could provide for all energy needs.Solar energy is unlimited in supply, but its exploitation and utilization are limited owing to the limitation of technology and conditions. Solar energy utilization needs an enormous amount of land, and there are economic and environmental problems related to the use of even a fraction of this amount of land for solar energy collection. Certainly, many residents of Arizona would not be pleased at having so much of the state devoted to solar collectors, and some environmental groups would protest the resultant shading of rattlesnake habitat. Solar power cells for the direct conversion of sunlight to electricity have been developed and are widely used for energy in space vehicles. With present technology, however, they remain too expensive for large-scale generation of electricity. Therefore, most schemes for the utilization of solar power depend upon the collection of thermal energy, followed by conversion to electrical energy. The simplest such approach involves focusing sunlight on a steam-generating bioler. Parabolic refkectors can be used to focus sunlight on pipescontaining heat-transporting fluids. Selective coatings on these pipes can be used so that only a small percentage of incident energy is reradiated from the pipes.（二）翻译全双桥电机保护驱动器（A3976）A3759是一种用来驱动双极性步进电机双绕组的单片集成电路，也可以用来双向控制两台电动机。

英文文献小短文(原文加汉语翻译)

A fern that hyperaccumulates arsenic(这是题目，百度一下就能找到原文好，原文还有表格，我没有翻译)A hardy, versatile, fast-growing plant helps to remove arsenic from contaminated soilsContamination of soils with arsenic,which is both toxic and carcinogenic, is widespread1. We have discovered that the fern Pteris vittata (brake fern) is extremely efficient in extracting arsenic from soils and translocating it into its above-ground biomass. This plant —which, to our knowledge, is the first known arsenic hyperaccumulator as well as the first fern found to function as a hyperaccumulator— has many attributes that recommend it for use in the remediation of arsenic-contaminated soils.We found brake fern growing on a site in Central Florida contaminated with chromated copper arsenate (Fig. 1a). We analysed the fronds of plants growing at the site for total arsenic by graphite furnace atomic absorption spectroscopy. Of 14 plant species studied, only brake fern contained large amounts of arsenic (As;3,280–4,980 p.p.m.). We collected additional samples of the plant and soil from the contaminated site (18.8–1,603 p.p.m. As) and from an uncontaminated site (0.47–7.56 p.p.m. As). Brake fern extracted arsenic efficiently from these soils into its fronds: plants growing in the contaminated site contained 1,442–7,526p.p.m. Arsenic and those from the uncontaminated site contained 11.8–64.0 p.p.m. These values are much higher than those typical for plants growing in normal soil, which contain less than 3.6 p.p.m. of arsenic3.As well as being tolerant of soils containing as much as 1,500 p.p.m. arsenic, brake fern can take up large amounts of arsenic into its fronds in a short time (Table 1). Arsenic concentration in fern fronds growing in soil spiked with 1,500 p.p.m. Arsenic increased from 29.4 to 15,861 p.p.m. in two weeks. Furthermore, in the same period, ferns growing in soil containing just 6 p.p.m. arsenic accumulated 755 p.p.m. Of arsenic in their fronds, a 126-fold enrichment. Arsenic concentrations in brake fern roots were less than 303 p.p.m., whereas those in the fronds reached 7,234 p.p.m.Addition of 100 p.p.m. Arsenic significantly stimulated fern growth, resulting in a 40% increase in biomass compared with the control (data not shown).After 20 weeks of growth, the plant was extracted using a solution of 1:1 methanol:water to speciate arsenic with high-performance liquid chromatography–inductively coupled plasma mass spectrometry. Almostall arsenic was present as relatively toxic inorganic forms, with little detectable organoarsenic species4. The concentration of As(III) was greater in the fronds (47–80%) than in the roots (8.3%), indicating that As(V) was converted to As(III) during translocation from roots to fronds.As well as removing arsenic from soils containing different concentrations of arsenic (Table 1), brake fern also removed arsenic from soils containing different arsenic species (Fig. 1c). Again, up to 93% of the arsenic was concentrated in the fronds. Although both FeAsO4 and AlAsO4 are relatively insoluble in soils1, brake fern hyperaccumulated arsenic derived from these compounds into its fronds (136–315 p.p.m.)at levels 3–6 times greater than soil arsenic.Brake fern is mesophytic and is widely cultivated and naturalized in many areas with a mild climate. In the United States, it grows in the southeast and in southern California5. The fern is versatile and hardy, and prefers sunny (unusual for a fern) and alkaline environments (where arsenic is more available). It has considerable biomass, and is fast growing, easy to propagate,and perennial.We believe this is the first report of significant arsenic hyperaccumulationby an unmanipulated plant. Brake fern has great potential to remediate arsenic-contaminated soils cheaply and could also aid studies of arsenic uptake, translocation, speciation, distribution and detoxification in plants. *Soil and Water Science Department, University ofFlorida, Gainesville, Florida 32611-0290, USAe-mail: lqma@†Cooperative Extension Service, University ofGeorgia, Terrell County, PO Box 271, Dawson,Georgia 31742, USA‡Department of Chemistry & SoutheastEnvironmental Research Center, FloridaInternational University, Miami, Florida 33199,1. Nriagu, J. O. (ed.) Arsenic in the Environment Part 1: Cyclingand Characterization (Wiley, New York, 1994).2. Brooks, R. R. (ed.) Plants that Hyperaccumulate Heavy Metals (Cambridge Univ. Press, 1998).3. Kabata-Pendias, A. & Pendias, H. in Trace Elements in Soils and Plants 203–209 (CRC, Boca Raton, 1991).4. Koch, I., Wang, L., Ollson, C. A., Cullen, W. R. & Reimer, K. J. Envir. Sci. Technol. 34, 22–26 (2000).5. Jones, D. L. Encyclopaedia of Ferns (Lothian, Melbourne, 1987).积累砷的蕨类植物耐寒，多功能，生长快速的植物，有助于从污染土壤去除砷有毒和致癌的土壤砷污染是非常广泛的。

外文参考文献(带中文翻译)

外文资料原文涂敏之会计学 8051208076Title:Future of SME finance（/docs/pos_papers/2004/041027_SME-finance_final.do c）Background – the environment for SME finance has changedFuture economic recovery will depend on the possibility of Crafts, Trades and SMEs to exploit their potential for growth and employment creation.SMEs make a major contribution to growth and employment in the EU and are at the heart of the Lisbon Strategy, whose main objective is to turn Europe into the most competitive and dynamic knowledge-based economy in the world. However, the ability of SMEs to grow depends highly on their potential to invest in restructuring, innovation and qualification. All of these investments need capital and therefore access to finance.Against this background the consistently repeated complaint of SMEs about their problems regarding access to finance is a highly relevant constraint that endangers the economic recovery of Europe.Changes in the finance sector influence the behavior of credit institutes towards Crafts, Trades and SMEs. Recent and ongoing developments in the banking sector add to the concerns of SMEs and will further endanger their access to finance. The main changes in the banking sector which influence SME finance are:•Globalization and internationalization have increased the competition and the profit orientation in the sector;•worsening of the economic situations in some institutes (burst of the ITC bubble, insolvencies) strengthen the focus on profitability further;•Mergers and restructuring created larger structures and many local branches, which had direct and personalized contacts with small enterprises, were closed;•up-coming implementation of new capital adequacy rules (Basel II) will also change SME business of the credit sector and will increase its administrative costs;•Stricter interpretation of State-Aide Rules by the European Commission eliminates the support of banks by public guarantees; many of the effected banks are very active in SME finance.All these changes result in a higher sensitivity for risks and profits in the finance sector.The changes in the finance sector affect the accessibility of SMEs to finance.Higher risk awareness in the credit sector, a stronger focus on profitability and the ongoing restructuring in the finance sector change the framework for SME finance and influence the accessibility of SMEs to finance. The most important changes are: •In order to make the higher risk awareness operational, the credit sector introduces new rating systems and instruments for credit scoring;•Risk assessment of SMEs by banks will force the enterprises to present more and better quality information on their businesses;•Banks will try to pass through their additional costs for implementing and running the new capital regulations (Basel II) to their business clients;•due to the increase of competition on interest rates, the bank sector demands more and higher fees for its services (administration of accounts, payments systems, etc.), which are not only additional costs for SMEs but also limit their liquidity;•Small enterprises will lose their personal relationship with decision-makers in local branches –the credit application process will become more formal and anonymous and will probably lose longer;•the credit sector will lose more and more its “public function” to provide access to finance for a wide range of economic actors, which it has in a number of countries, in order to support and facilitate economic growth; the profitability of lending becomes the main focus of private credit institutions.All of these developments will make access to finance for SMEs even more difficult and / or will increase the cost of external finance. Business start-ups and SMEs, which want to enter new markets, may especially suffer from shortages regarding finance. A European Code of Conduct between Banks and SMEs would have allowed at least more transparency in the relations between Banks and SMEs and UEAPME regrets that the bank sector was not able to agree on such a commitment.Towards an encompassing policy approach to improve the access of Crafts, Trades and SMEs to financeAll analyses show that credits and loans will stay the main source of finance for the SME sector in Europe. Access to finance was always a main concern for SMEs,but the recent developments in the finance sector worsen the situation even more. Shortage of finance is already a relevant factor, which hinders economic recovery in Europe. Many SMEs are not able to finance their needs for investment.Therefore, UEAPME expects the new European Commission and the new European Parliament to strengthen their efforts to improve the framework conditions for SME finance. Europe’s Crafts, Trades and SMEs ask for an encompassing policy approach, which includes not only the conditions for SMEs’ access to lending, but will also strengthen their capacity for internal finance and their access to external risk capital.From UEAPM E’s point of view such an encompassing approach should be based on three guiding principles:•Risk-sharing between private investors, financial institutes, SMEs and public sector;•Increase of transparency of SMEs towards their external investors and lenders;•improving the regulatory environment for SME finance.Based on these principles and against the background of the changing environment for SME finance, UEAPME proposes policy measures in the following areas:1. New Capital Requirement Directive: SME friendly implementation of Basel IIDue to intensive lobbying activities, UEAPME, together with other Business Associations in Europe, has achieved some improvements in favour of SMEs regarding the new Basel Agreement on regulatory capital (Basel II). The final agreement from the Basel Committee contains a much more realistic approach toward the real risk situation of SME lending for the finance market and will allow the necessary room for adaptations, which respect the different regional traditions and institutional structures.However, the new regulatory system will influence the relations between Banks and SMEs and it will depend very much on the way it will be implemented into European law, whether Basel II becomes burdensome for SMEs and if it will reduce access to finance for them.The new Capital Accord form the Basel Committee gives the financial market authorities and herewith the European Institutions, a lot of flexibility. In about 70areas they have room to adapt the Accord to their specific needs when implementing it into EU law. Some of them will have important effects on the costs and the accessibility of finance for SMEs.UEAPME expects therefore from the new European Commission and the new European Parliament:•The implementation of the new Capital Requirement Directive will be costly for the Finance Sector (up to 30 Billion Euro till 2006) and its clients will have to pay for it. Therefore, the implementation – especially for smaller banks, which are often very active in SME finance –has to be carried out with as little administrative burdensome as possible (reporting obligations, statistics, etc.).•The European Regulators must recognize traditional instruments for collaterals (guarantees, etc.) as far as possible.•The European Commission and later the Member States should take over the recommendations from the European Parliament with regard to granularity, access to retail portfolio, maturity, partial use, adaptation of thresholds, etc., which will ease the burden on SME finance.2. SMEs need transparent rating proceduresDue to higher risk awareness of the finance sector and the needs of Basel II, many SMEs will be confronted for the first time with internal rating procedures or credit scoring systems by their banks. The bank will require more and better quality information from their clients and will assess them in a new way. Both up-coming developments are already causing increasing uncertainty amongst SMEs.In order to reduce this uncertainty and to allow SMEs to understand the principles of the new risk assessment, UEAPME demands transparent rating procedures –rating procedures may not become a “Black Box” for SMEs:•The bank should communicate the relevant criteria affecting the rating of SMEs.•The bank should inform SMEs about its assessment in order to allow SMEs to improve.The negotiations on a European Code of Conduct between Banks and SMEs , which would have included a self-commitment for transparent rating procedures by Banks, failed. Therefore, UEAPME expects from the new European Commission and the new European Parliament support for:•binding rules in the framework of the new Capital Adequacy Directive, which ensure the transparency of rating procedures and credit scoring systems for SMEs;•Elaboration of national Codes of Conduct in order to improve the relations between Banks and SMEs and to support the adaptation of SMEs to the new financial environment.3. SMEs need an extension of credit guarantee systems with a special focus on Micro-LendingBusiness start-ups, the transfer of businesses and innovative fast growth SMEs also depended in the past very often on public support to get access to finance. Increasing risk awareness by banks and the stricter interpretation of State Aid Rules will further increase the need for public support.Already now, there are credit guarantee schemes in many countries on the limit of their capacity and too many investment projects cannot be realized by SMEs.Experiences show that Public money, spent for supporting credit guarantees systems, is a very efficient instrument and has a much higher multiplying effect than other instruments. One Euro form the European Investment Funds can stimulate 30 Euro investments in SMEs (for venture capital funds the relation is only 1:2).Therefore, UEAPME expects the new European Commission and the new European Parliament to support:•The extension of funds for national credit guarantees schemes in the framework of the new Multi-Annual Programmed for Enterprises;•The development of new instruments for securitizations of SME portfolios;•The recognition of existing and well functioning credit guarantees schemes as collateral;•More flexibility within the European Instruments, because of national differences in the situation of SME finance;•The development of credit guarantees schemes in the new Member States;•The development of an SBIC-like scheme in the Member States to close the equity gap (0.2 – 2.5 Mio Euro, according to the expert meeting on PACE on April 27 in Luxemburg).•the development of a financial support scheme to encourage the internalizations of SMEs (currently there is no scheme available at EU level: termination of JOP, fading out of JEV).4. SMEs need company and income taxation systems, which strengthen their capacity for self-financingMany EU Member States have company and income taxation systems with negative incentives to build-up capital within the company by re-investing their profits. This is especially true for companies, which have to pay income taxes. Already in the past tax-regimes was one of the reasons for the higher dependence of Europe’s SMEs on bank lending. In future, the result of rating will also depend on the amount of capital in the company; the high dependence on lending will influence the access to lending. This is a vicious cycle, which has to be broken.Even though company and income taxation falls under the competence of Member States, UEAPME asks the new European Commission and the new European Parliament to publicly support tax-reforms, which will strengthen the capacity of Crafts, Trades and SME for self-financing. Thereby, a special focus on non-corporate companies is needed.5. Risk Capital – equity financingExternal equity financing does not have a real tradition in the SME sector. On the one hand, small enterprises and family business in general have traditionally not been very open towards external equity financing and are not used to informing transparently about their business.On the other hand, many investors of venture capital and similar forms of equity finance are very reluctant regarding investing their funds in smaller companies, which is more costly than investing bigger amounts in larger companies. Furthermore it is much more difficult to set out of such investments in smaller companies.Even though equity financing will never become the main source of financing for SMEs, it is an important instrument for highly innovative start-ups and fast growing companies and it has therefore to be further developed. UEAPME sees three pillars for such an approach where policy support is needed:Availability of venture capital•The Member States should review their taxation systems in order to create incentives to invest private money in all forms of venture capital.•Guarantee instruments for equity financing should be further developed.Improve the conditions for investing venture capital into SMEs•The development of secondary markets for venture capital investments in SMEs should be supported.•Accounting Standards for SMEs should be revised in order to ease transparent exchange of information between investor and owner-manager.Owner-managers must become more aware about the need for transparency towards investors•SME owners will have to realise that in future access to external finance (venture capital or lending) will depend much more on a transparent and open exchange of information about the situation and the perspectives of their companies.•In order to fulfil the new needs for transparency, SMEs will have to use new information instruments (business plans, financial reporting, etc.) and new management instruments (risk-management, financial management, etc.).外文资料翻译涂敏之会计学 8051208076题目：未来的中小企业融资背景：中小企业融资已经改变未来的经济复苏将取决于能否工艺品，贸易和中小企业利用其潜在的增长和创造就业。

文学作品中英文对照外文翻译文献

文学作品中英文对照外文翻译文献
本文旨在汇总文学作品中的英文和中文对照外文翻译文献，共有以下几篇：
1. 《傲慢与偏见》
翻译：英文原版名为“Pride and Prejudice”，中文版由钱钟书翻译。

该小说是英国作家简.奥斯汀的代表作之一，描绘了19世纪英国中上层社会的生活和爱情故事。

2. 《了不起的盖茨比》
翻译：英文原版名为“The Great Gatsby”，中文版由杨绛翻译。

小说主要讲述了一个居住在纽约长岛的年轻白领盖茨比为了追求他的旧爱黛西而付出的努力，是20世纪美国文学的经典之作。

3. 《麦田里的守望者》
翻译：英文原版名为“The Catcher in the Rye”，中文版由施蛰存翻译。

该小说主人公霍尔顿是美国现代文学中最为知名的反英雄形象之一，作品深刻地揭示了青少年内心的孤独和矛盾。

4. 《1984》
翻译：英文原版名为“1984”，中文版由李敬瑞翻译。

该小说是英国作家乔治.奥威尔的代表作之一，描绘了一个虚构的极权主义社会。

以上是部分文学作品的中英文对照外文翻译文献，可以帮助读者更好地理解和学习相关文学作品。

外文文献翻译原文+译文

外文文献翻译原文Analysis of Con tin uous Prestressed Concrete BeamsChris BurgoyneMarch 26, 20051、IntroductionThis conference is devoted to the development of structural analysis rather than the strength of materials, but the effective use of prestressed concrete relies on an appropriate combination of structural analysis techniques with knowledge of the material behaviour. Design of prestressed concrete structures is usually left to specialists; the unwary will either make mistakes or spend inordinate time trying to extract a solution from the various equations.There are a number of fundamental differences between the behaviour of prestressed concrete and that of other materials. Structures are not unstressed when unloaded; the design space of feasible solutions is totally bounded；in hyperstatic structures, various states of self-stress can be induced by altering the cable profile, and all of these factors get influenced by creep and thermal effects. How were these problems recognised and how have they been tackled?Ever since the development of reinforced concrete by Hennebique at the end of the 19th century (Cusack 1984), it was recognised that steel and concrete could be more effectively combined if the steel was pretensioned, putting the concrete into compression. Cracking could be reduced, if not prevented altogether, which would increase stiffness and improve durability. Early attempts all failed because the initial prestress soon vanished, leaving the structure to be- have as though it was reinforced; good descriptions of these attempts are given by Leonhardt (1964) and Abeles (1964).It was Freyssineti’s observations of the sagging of the shallow arches on three bridges that he had just completed in 1927 over the River Allier near Vichy which led directly to prestressed concrete (Freyssinet 1956). Only the bridge at Boutiron survived WWII (Fig 1). Hitherto, it had been assumed that concrete had a Young’s modulus which remained fixed, but he recognised that the de- ferred strains due to creep explained why the prestress had been lost in the early trials. Freyssinet (Fig. 2) also correctly reasoned that high tensile steel had to be used, so that some prestress would remain after the creep had occurred, and alsothat high quality concrete should be used, since this minimised the total amount of creep. The history of Freyssineti’s early prestressed concrete work is written elsewhereFigure1:Boutiron Bridge,Vic h yFigure 2: Eugen FreyssinetAt about the same time work was underway on creep at the BRE laboratory in England ((Glanville 1930) and (1933)). It is debatable which man should be given credit for the discovery of creep but Freyssinet clearly gets the credit for successfully using the knowledge to prestress concrete.There are still problems associated with understanding how prestressed concrete works, partly because there is more than one way of thinking about it. These different philosophies are to some extent contradictory, and certainly confusing to the young engineer. It is also reflected, to a certain extent, in the various codes of practice.Permissible stress design philosophy sees prestressed concrete as a way of avoiding cracking by eliminating tensile stresses; the objective is for sufficient compression to remain after creep losses. Untensionedreinforcement, which attracts prestress due to creep, is anathema. This philosophy derives directly from Freyssinet’s logic and is primarily a working stress concept.Ultimate strength philosophy sees prestressing as a way of utilising high tensile steel as reinforcement. High strength steels have high elastic strain capacity, which could not be utilised when used as reinforcement; if the steel is pretensioned, much of that strain capacity is taken out before bonding the steel to the concrete. Structures designed this way are normally designed to be in compression everywhere under permanent loads, but allowed to crack under high live load. The idea derives directly from the work of Dischinger (1936) and his work on the bridge at Aue in 1939 (Schonberg and Fichter 1939), as well as that of Finsterwalder (1939). It is primarily an ultimate load concept. The idea of partial prestressing derives from these ideas.The Load-Balancing philosophy, introduced by T.Y. Lin, uses prestressing to counter the effect of the permanent loads (Lin 1963). The sag of the cables causes an upward force on the beam, which counteracts the load on the beam. Clearly, only one load can be balanced, but if this is taken as the total dead weight, then under that load the beam will perceive only the net axial prestress and will have no tendency to creep up or down.These three philosophies all have their champions, and heated debates take place between them as to which is the most fundamental.2、Section designFrom the outset it was recognised that prestressed concrete has to be checked at both the working load and the ultimate load. For steel structures, and those made from reinforced concrete, there is a fairly direct relationship between the load capacity under an allowable stress design, and that at the ultimate load under an ultimate strength design. Older codes were based on permissible stresses at the working load; new codes use moment capacities at the ultimate load. Different load factors are used in the two codes, but a structure which passes one code is likely to be acceptable under the other.For prestressed concrete, those ideas do not hold, since the structure is highly stressed, even when unloaded. A small increase of load can cause some stress limits to be breached, while a large increase in load might be needed to cross other limits. The designer has considerable freedom to vary both the working load and ultimate load capacities independently; both need to be checked.A designer normally has to check the tensile and compressive stresses, in both the top and bottom fibre of the section, for every load case. The critical sections are normally, but not always, the mid-span and the sections over piers but other sections may become critical ，when the cable profile has to be determined.The stresses at any position are made up of three components, one of which normally has a different sign from the other two; consistency of sign convention is essential.If P is the prestressing force and e its eccentricity, A and Z are the area of the cross-section and its elastic section modulus, while M is the applied moment, then where ft and fc are the permissible stresses in tension and compression.c e t f ZM Z P A P f ≤-+≤Thus, for any combination of P and M , the designer already has four in- equalities to deal with.The prestressing force differs over time, due to creep losses, and a designer isusually faced with at least three combinations of prestressing force and moment;• the applied moment at the time the prestress is first applied, before creep losses occur,• the maximum applied moment after creep losses, and• the minimum applied moment after creep losses.Figure 4: Gustave MagnelOther combinations may be needed in more complex cases. There are at least twelve inequalities that have to be satisfied at any cross-section, but since an I-section can be defined by six variables, and two are needed to define the prestress, the problem is over-specified and it is not immediately obvious which conditions are superfluous. In the hands of inexperienced engineers, the design process can be very long-winded. However, it is possible to separate out the design of the cross-section from the design of the prestress. By considering pairs of stress limits on the same fibre, but for different load cases, the effects of the prestress can be eliminated, leaving expressions of the form:rangestress e Perm issibl Range Mom entZ These inequalities, which can be evaluated exhaustively with little difficulty, allow the minimum size of the cross-section to be determined.Once a suitable cross-section has been found, the prestress can be designed using a construction due to Magnel (Fig.4). The stress limits can all be rearranged into the form:()M fZ PA Z e ++-≤1 By plotting these on a diagram of eccentricity versus the reciprocal of the prestressing force, a series of bound lines will be formed. Provided the inequalities (2) are satisfied, these bound lines will always leave a zone showing all feasible combinations of P and e. The most economical design, using the minimum prestress, usually lies on the right hand side of the diagram, where the design is limited by the permissible tensile stresses.Plotting the eccentricity on the vertical axis allows direct comparison with the crosssection, as shown in Fig. 5. Inequalities (3) make no reference to the physical dimensions of the structure, but these practical cover limits can be shown as wellA good designer knows how changes to the design and the loadings alter the Magnel diagram. Changing both the maximum andminimum bending moments, but keeping the range the same, raises and lowers the feasible region. If the moments become more sagging the feasible region gets lower in the beam.In general, as spans increase, the dead load moments increase in proportion to the live load. A stage will be reached where the economic point (A on Fig.5) moves outside the physical limits of the beam; Guyon (1951a) denoted the limiting condition as the critical span. Shorter spans will be governed by tensile stresses in the two extreme fibres, while longer spans will be governed by the limiting eccentricity and tensile stresses in the bottom fibre. However, it does not take a large increase in moment ，at which point compressive stresses will govern in the bottom fibre under maximum moment.Only when much longer spans are required, and the feasible region moves as far down as possible, does the structure become governed by compressive stresses in both fibres.3、Continuous beamsThe design of statically determinate beams is relatively straightforward; the engineer can work on the basis of the design of individual cross-sections, as outlined above. A number of complications arise when the structure is indeterminate which means that the designer has to consider, not only a critical section,but also the behaviour of the beam as a whole. These are due to the interaction of a number of factors, such as Creep, Temperature effects and Construction Sequence effects. It is the development of these ideas whichforms the core of this paper. The problems of continuity were addressed at a conference in London (Andrew and Witt 1951). The basic principles, and nomenclature, were already in use, but to modern eyes concentration on hand analysis techniques was unusual, and one of the principle concerns seems to have been the difficulty of estimating losses of prestressing force.3.1 Secondary MomentsA prestressing cable in a beam causes the structure to deflect. Unlike the statically determinate beam, where this motion is unrestrained, the movement causes a redistribution of the support reactions which in turn induces additional moments. These are often termed Secondary Moments, but they are not always small, or Parasitic Moments, but they are not always bad.Freyssinet’s bridge across the Marne at Luzancy, started in 1941 but not completed until 1946, is often thought of as a simply supported beam, but it was actually built as a two-hinged arch (Harris 1986), with support reactions adjusted by means of flat jacks and wedges which were later grouted-in (Fig.6). The same principles were applied in the later and larger beams built over the same river.Magnel built the first indeterminate beam bridge at Sclayn, in Belgium (Fig.7) in 1946. The cables are virtually straight, but he adjusted the deck profile so that the cables were close to the soffit near mid-span. Even with straight cables the sagging secondary momentsare large; about 50% of the hogging moment at the central support caused by dead and live load.The secondary moments cannot be found until the profile is known but the cablecannot be designed until the secondary moments are known. Guyon (1951b) introduced the concept of the concordant profile, which is a profile that causes no secondary moments; es and ep thus coincide. Any line of thrust is itself a concordant profile.The designer is then faced with a slightly simpler problem; a cable profile has to be chosen which not only satisfies the eccentricity limits (3) but is also concordant. That in itself is not a trivial operation, but is helped by the fact that the bending moment diagram that results from any load applied to a beam will itself be a concordant profile for a cable of constant force. Such loads are termed notional loads to distinguish them from the real loads on the structure. Superposition can be used to progressively build up a set of notional loads whose bending moment diagram gives the desired concordant profile.3.2 Temperature effectsTemperature variations apply to all structures but the effect on prestressed concrete beams can be more pronounced than in other structures. The temperature profile through the depth of a beam (Emerson 1973) can be split into three components for the purposes of calculation (Hambly 1991). The first causes a longitudinal expansion, which is normally released by the articulation of the structure; the second causes curvature which leads to deflection in all beams and reactant moments in continuous beams, while the third causes a set of self-equilibrating set of stresses across the cross-section.The reactant moments can be calculated and allowed-for, but it is the self- equilibrating stresses that cause the main problems for prestressed concrete beams. These beams normally have high thermal mass which means that daily temperature variations do not penetrate to the core of the structure. The result is a very non-uniform temperature distribution across the depth which in turn leads to significant self-equilibrating stresses. If the core of the structure is warm, while the surface is cool, such as at night, then quite large tensile stresses can be developed on the top and bottom surfaces. However, they only penetrate a very short distance into the concrete and the potential crack width is very small. It can be very expensive to overcome the tensile stress by changing the section or the prestress。

(完整word版)外文文献及翻译doc

Criminal Law1.General IntroductionCriminal law is the body of the law that defines criminal offenses, regulates the apprehension, charging, and trial of suspected offenders,and fixes punishment for convicted persons. Substantive criminal law defines particular crimes, and procedural law establishes rules for the prosecution of crime. In a democratic society, it is the function of the legislative bodies to decide what behavior will be made criminal and what penalties will be attached to violations of the law.Capital punishment may be imposed in some jurisdictions for the most serious crimes. And physical or corporal punishment may still be imposed such as whipping or caning, although these punishments are prohibited in much of the world. A convict may be incarcerated in prison or jail and the length of incarceration may vary from a day to life.Criminal law is a reflection of the society that produce it. In an Islamic theocracy, such as Iran, criminal law will reflect the religious teachings of the Koran; in an Catholic country, it will reflect the tenets of Catholicism. In addition, criminal law will change to reflect changes in society, especially attitude changes. For instance, use of marijuana was once considered a serious crime with harsh penalties, whereas today the penalties in most states are relatively light. As severity of the penaltieswas reduced. As a society advances, its judgments about crime and punishment change.2.Elements of a CrimeObviously, different crimes require different behaviors, but there are common elements necessary for proving all crimes. First, the prohibited behavior designated as a crime must be clearly defined so that a reasonable person can be forewarned that engaging in that behavior is illegal. Second, the accused must be shown to have possessed the requisite intent to commit the crime. Third, the state must prove causation. Finally, the state must prove beyond a reasonable doubt that the defendant committed the crime.(1) actus reusThe first element of crime is the actus reus.Actus is an act or action and reus is a person judicially accused of a crime. Therefore, actus reus is literally the action of a person accused of a crime. A criminal statute must clearly define exactly what act is deemed “guilty”---that is, the exact behavior that is being prohibited. That is done so that all persons are put on notice that if they perform the guilty act, they will be liable for criminal punishment. Unless the actus reus is clearly defined, one might not know whether or not on e’s behavior is illegal.Actus reus may be accomplished by an action, by threat of action,or exceptionally, by an omission to act, which is a legal duty to act. For example, the act of Cain striking Abel might suffice, or a parent’s failure to give to a young child also may provide the actus reus for a crime.Where the actus reus is a failure to act, there must be a duty of care. A duty can arise through contract, a voluntary undertaking, a blood relation, and occasionally through one’s official position. Duty also can arise from one’s own creation of a dangerous situation.(2)mens reaA second element of a crime is mens rea. Mens rea refers to an individual’s state of mind when a crime is committed. While actus reus is proven by physical or eyewitness evidence, mens rea is more difficult to ascertain. The jury must determine for itself whether the accused had the necessary intent to commit the act.A lower threshold of mens rea is satisfied when a defendant recognizes an act is dangerous but decides to commit it anyway. This is recklessness. For instance, if Cain tears a gas meter from a wall, and knows this will let flammable gas escape into a neighbor’s house, he could be liable for poisoning. Courts often consider whether the actor did recognise the danger, or alternatively ought to have recognized a danger (though he did not) is tantamount to erasing intent as a requirement. In this way, the importance of mens rea hasbeen reduced in some areas of the criminal law.Wrongfulness of intent also may vary the seriousness of an offense. A killing committed with specific intent to kill or with conscious recognition that death or serious bodily harm will result, would be murder, whereas a killing affected by reckless acts lacking such a consciousness could be manslaughter.(3)CausationThe next element is causation. Often the phrase “but for”is used to determine whether causation has occurred. For example, we might say “Cain caused Abel”, by which we really mean “Cain caused Abel’s death. ”In other words, ‘but for Cain’s act, Abel would still be alive.” Causation, then, means “but for” the actions of A, B would not have been harmed. In criminal law, causation is an element that must be proven beyond a reasonable doubt.(4) Proof beyond a Reasonable DoubtIn view of the fact that in criminal cases we are dealing with the life and liberty of the accused person, as well as the stigma accompanying conviction, the legal system places strong limits on the power of the state to convict a person of a crime. Criminal defendants are presumed innocent. The state must overcome this presumption of innocence by proving every element of the offense charged against the defendant beyond a reasonable doubt to thesatisfaction of all the jurors. This requirement is the primary way our system minimizes the risk of convicting an innocent person.The state must prove its case within a framework of procedural safeguards that are designed to protect the accused. The state’s failure to prove any material element of its case results in the accused being acquitted or found not guilty, even though he or she may actually have committed the crime charged.3. Strict LiabilityIn modern society, some crimes require no more mens rea, and they are known as strict liability offenses. For in stance, under the Road Traffic Act 1988 it is a strict liability offence to drive a vehicle with an alcohol concentration above the prescribed limit.Strict liability can be described as criminal or civil liability notwithstanding the lack mens rea or intent by the defendant. Not all crimes require specific intent, and the threshold of culpability required may be reduced. For example, it might be sufficient to show that a defendant acted negligently, rather than intentionally or recklessly.1. 概述刑法是规定什么试犯罪，有关犯罪嫌疑人之逮捕、起诉及审判，及对已决犯处以何种刑罚的部门法。

学前教育英文文献及翻译

学前教育英文文献及翻译学前教育是指对幼儿进行的早期教育和培养，是一个关键阶段，对幼儿的发展起着重要作用。

以下是几篇经典的英文文献及其翻译，希望能为学前教育工作者和家长提供一些参考。

文献一：Early Childhood Education: The Key to SuccessEarly childhood education is the foundation for lifelong learning. It is during these early years that children developthe essential skills and knowledge that will set them up for success in school and in life. Research has shown that high-quality early childhood education programs can have a significant impact on a child’s academic and social development.翻译一：学前教育：成功的关键学前教育是终生学习的基础。

在这些早期岁月，孩子们发展出将他们在学校和生活中成功的必要技能和知识。

研究表明，高质量的学前教育计划对孩子的学术和社交发展有显著影响。

文献二：The Role of Play in Early Childhood EducationPlay is an essential part of early childhood education. It is through play that children learn about the world around them, develop their imagination and creativity, and build important social and emotional skills. Play-based learning can help children engage with their environment, problem-solve, and develop a love for learning.翻译二：在学前教育中的游戏角色游戏是学前教育的一个重要组成部分。

1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。

步进电机的知识什么是步进电机：步进电机是一种把电脉冲转化为角位移的执行机构。

通俗的说：当驱动程序收到一个步进脉冲信号，将驱动步进电机轴旋转一个固定的角度（步进角）。

您可以通过控制脉冲个数来控制角位移，从而达到准确定位的目的;同时，你可以通过控制脉冲频率来控制电机的旋转速度和加速度，实现速度控制的目的。

步进电机的种类：步进电机分为三种：永磁式（PM），反应式（VR）和混合式（HR）永磁式步进电机一般为两相，转矩和体积较小，步进角一步7.5度或15度;反应式一般有三相可以实现大转矩输出，步进角一般是1.5度，但噪声和振动大。

在欧洲和美洲80个国家已被淘汰;混合式步进是混合了永磁式和反应的优势。

它由两相和五相：一般两相的步距角是1.8度，而的五相步距角为0.72度。

是使用最广泛的的步进电机。

步进电机允许的最高表面温度步进电机温度过高首先会的磁性材料退磁，导致转矩降低甚至失步，电机表面温度允许的最大值取决于的磁性材料退磁点;一般来说，磁性材料退磁点在摄氏130度以上有些材料甚至高达摄氏200度高，所以步进电机表面温度在摄氏80-90度是正常的。

步进电机精度为多少？是否累积一般步进电机的精度为步进角的3-5%，且不累积如何确定步进电机驱动器直流电源A.电压确定混合式步进电机驱动器的电源电压范围较广（比如IM483的供电电压12〜48VDC），电源电压通常根据电机的转速和响应要求来选择。

如果要求较快的运行速度较高的响应速度就选用较高的电压，但注意电源电压的峰值不能超过驱动器的最大输入电压，否则可能会损坏驱动器。

B.电流确定电源电流一般根据输出相电流I来确定。

如果采用线性电源，电源电流一般可取I的1.1〜1.3倍;如果采用开关电源，电源电流一般可取I的1.5〜2.0倍。

步进电机的主要特性在步进电机关机时要确保没有脉冲信号，当电机运行时如果加入适当的脉冲信号，它会转过一定的角度（称为步距角是）。

转速与脉冲频率成正比。

2龙式步进电机步距角7.5度，旋转360度，需要48个脉冲来完成。

3步进电机具有快速启动和停止的优良特性。

4只要改变脉冲，可以很容易地改变电机轴旋转的方向。

因此，目前的打印机，绘图仪，机器人设备以步进电机作为动力核心。

步进电机控制的例子我们以四相单极步进电机为例：四个相绕组引出四个相和两个公共线（连接到正极）。

一相接地。

会被激发，。

我们使用四相八拍控制，即第1阶段第2阶段交替反过来，会提高分辨率。

步距角0.9°，可以转移到控制电机励磁是为了转移如下：如果电机反转的要求，传输的激励信号可以逆转的。

2控制方案控制系统框图如下该方案采用AT89S51的主要控制装置。

它是与AT89C51兼容，但也增加了SPI接口和看门狗模块，这不仅使调试变得更容易，也更稳定。

单片机程序主要用于现场信号的采集和通过步进电机的运转来计算的方向和速度信息。

然后将信息发送到CPLD。

CPLD使用EPM7128SLC84-15，ALTERA公司的MAX7000系列可编程逻辑器件EPM7128。

具有高阻抗，电可擦除等特点，可用单位数为2500单位，工作电压+5 V CPLD接收脉冲后转换为相应的控制信号输出到步进电机驱动器，从微控制器发送的信息。

输入后把控制信号发送到驱动电机绕组，以达到有效控制电机的目的。

2.1为电机驱动器的硬件结构电机驱动器通过下面的电路来实现：R1〜R8的电阻值为320Ω。

R9-R12的电阻值为2.2KΩ。

Q1〜Q4作为达林顿401A，Q5-Q8为S8550。

J1，J2和步进电机连接到六个接口。

步进电机优点和缺点优势1。

电机的旋转角度与脉冲数成正比;2。

当电机停转为最大转矩（当绕组励磁时）;3。

由于每一步准确度为百分之三到五，而且误差不会累积到下一步，因而具有更好定位精度和重复定位精度;4。

优良的启动和制动特性_;5。

没有电刷，可靠性高，电机的寿命只是取决于电机轴承;6。

电机_仅由输入脉冲数决定，可用于开环控制，这使得电机和控制结构确定相对简单系统成本7。

只是负载直接连接到电机轴也可以极其缓慢旋转8。

速度与的脉冲频率成正比，因此，有相对较宽的调速范围缺点1。

如果没有适当的控制，容易共振;2。

高速操作难度较大3。

难以获得大转矩4。

没有体积小，重量轻，能耗低，效率高等方面优势5。

过载时会破坏同步性，工作时会发出时较大的振动和噪音步进电机驱动要求（1）为了满足速度迅速上升或下降的要求，波形应当尽可能接近矩形以释放回路电流流，绕组两端的反电动势，加速电流衰减（2）具有较高功率和效率步进电机驱动器，把输入的脉冲信号转化为角位移，每当控制系统发出一个脉冲信号，步进电机驱动就旋转一个步距角，步进电机的速度与的脉冲信号频率成正比，因此，通过控制脉冲信号频率，就可以精确控制电机转速步进脉冲数决定准确连接为电机步进电机驱动器有很多，我们应该根据功率采取的合理的方式选择驱动器最新的技术发展国内和国际上对于驱动技术的研究十分活跃，高性能子驱动电路可以细分成几千部分甚至任意细分，现在已经能够做到通过复杂的计算统一步距角，大大提高了步进电机的脉冲分辨率，减少或消除振动，噪声和转矩波动，步进电机有了更多“类伺服”功能实际作用：步距角细分驱动器出现之前，用户需要选择不同的相来获取不同的步进电机步距角，以满足自己的要求，如果使用细分驱动器，用户可以通过更改驱动器号段，来改变实际的步距角，相数对实际步距角的作用几乎可以忽略不计AT89C51的介绍描述AT89C51是一个拥有4K字节FLASH编程功能和可擦除只读储存器的低功耗，高性能CMOS8位微机（PEROM）。

该设备是采用Atmel的高密度非易失性内存技术并与工业标准的的MCS-51指令集和引脚兼容。

芯片上的Flash允许程序存储器通过系统或由传统的非易失性存储器编程重新编程。

通过把一个多功能8位CPU与一个单一的芯片上的Flash相结合的，Atmel的AT89C51是一个功能强大微型计算机为许多嵌入式控制程序提供了高度灵活和成本效益的解决方案。

功能特点AT89C51具有以下功能：4K字节的Flash，128字节RAM，32 I / O口，两个16位定时器/计数器，一个五向量2级中断机构，一个全双工串行口，芯片振荡器和时钟电路。

此外，AT89C51支持频率为0的静态逻辑运算，并支持两种节电模式。

空闲模式时CPU停止工作，同时允许RAM，定时器/计数器，串口和中断系统继续运作。

掉电模式保存RAM的内容，但冻结振荡器，禁用所有其他芯片功能，直到硬件复位。

引脚描述VCC：电源电压GND：地端口0：端口0是一个8位漏极开路双向I / O端口。

作为一个输出端口，每个引脚可以驱动8个TTL 输入端。

当1写入端口0引脚，引脚可作为高阻输入端.端口0也可以设定成地址/数据在访问外部程序和数据存储器时的总线。

在这种模式下，口0内部上拉.电阻口0 在Flash编程期间也可以收到代码字节，输出程序改变的代码字节。

程序改变期间还要外部上拉电阻端口1端口1是一个具有内部上拉电阻的8位双向I / O端口端口1输出缓冲器可以驱动四个TTL 输入.当1被写入端口1它们被内部上拉电阻上拉为高电平并可以用作输入口。

作为输入口时，由于内部上拉电阻的作用，引脚被外部信号拉低时输出一个电流，flash编程和校验时端口1也会接收到低地址信号。

端口2端口2是一个具有内部上拉电阻的8位双向I / O端口。

端口2输出缓冲器可以驱动四个TTL 输入。

当1S写入端口2引脚他们被内部上拉电阻拉到高电平，并可以用作输入口。

作为输入口时，由于内部上拉电阻的做用，端口2引脚被外部信号拉至低电平时，将输出电流，端口2在访问使用16位地址的外部数据存储器时发出的高位地址字节。

在此应用中，它采用强大的内部上拉电阻，发光1S。

在访问使用8位地址的外部数据存储器时，端口2也会收到一些高八位地址信号或者控制信号。

端口3端口3是一个具有内部上拉电阻的8位双向I / O端口。

端口3输出缓冲器可以驱动四个TTL 输入。

当1S被写入端口3的引脚，他们被内部上拉电阻拉到高电平，并可以用作输入口。

作为输入口时，由于内部上拉电阻的做用，端口2引脚被外部信号拉至低电平时，将输出电流。

端口3还为A T89C51提供各种特殊功能，如下：RST复位输入引脚。

震荡器运行时，两个运行周期的高电平将使设备复位。

ALE / PROG在访问外部存储器时地址锁存使能输出脉冲锁存的低八位地址。

该引脚也是程序在Flash 编程时的PROG。

正常运行时ALE以恒定的速率发出振荡频率的1/6的脉冲信号，可用作外部时钟或定时。

但是请注意，，在每次访问外部数据存储器都有一个ALE脉冲跳过。

如果需要，可以通过把0 SFR置位为8EH来禁用ALE。

此时，ALE仅执行MOVX或MOVC 指令。

如果单片机在执行外部的工作，应将ALE设置为禁用。

PSEN程序储存允许输出是外部程序存储器的读选通信号，当A T89C51由外部程序存储器读取指令时，每个机器周期两次PSEN 有效，即输出两个脉冲。

在此期间，当访问外部数据存储器时，这两次有效的PSEN 信号不出现。

EA/ VPP外部访问允许。

EA必须绑到GND才能使设备开始在0000H到FFFFH位取代码。

但是请注意，如果锁存位1被编程，EA将锁存位置上复位。

若EA为高电平则单片机执行内部程序。

在Flash编程时，也可以使用使用12V编程电压VCCXTAL1：震荡器反相放大器及内部时钟发生器的输入端。

XTAL2：震荡器反相放大器的输出端。

时钟振荡器的特性时钟振荡器是可以设置为内部振荡器的反相放大器XTAL1和XTAL2分别为其出入端和输出端，如图1所示。

石英晶体或陶瓷谐振器都可以作为其材料。

如图2所示要想通过外部时钟来驱动它，XTAL1工作时XTAL2应悬空。

对外部时钟信号的占空比没有特殊要求，因为外部时钟信号是通过一个2分频触发器后作为内部时钟信号的，但最小高电平持续时间和最大的低电平持续时间应该符合要求。

内部振荡电路外部振荡电路闲散模式在闲散模式下，CPU停止工作，而所有其他元件依然处于工作状态。

该模式是通过软件控制的。

这种模式下，片上RAM和所有特殊功能寄存器的内部数据不变。

该模式可以由任何可用的终止指令或者硬件重置来终止当由硬件复位来终止闲散工作模式时，中央处理器CPU 通常是从激活空闲模式那条指令的下一条开始继续执行程序的，要完成内部复位操作，硬件复位脉冲要保持两个机器周期有效，在这种情况下，内部禁止中央处理器CPU访问片内RAM，而允许访问其他端口，这是为了避免可能对端口产生的意外写入：激活空闲模式的指令后面的一条指令不应是一条对端口或外部存储器的写入指令。

掉电模式在掉电模式下，振荡器停止运行，断电指令是最后一条要执行的指令。

英文文献及其翻译

英文文献翻译

英文文献整篇翻译

最新3000字英文参考文献及其翻译范例

外文文献及翻译

中英文文献以及翻译(化工类)

英文文献全文翻译

英文文献+翻译

英文文献原文及对应翻译

英文文献及翻译

英文文献小短文(原文加汉语翻译)

英文文献及翻译(计算机专业)

外文文献及翻译

英文文献小短文(原文加汉语翻译)

外文参考文献(带中文翻译)

文学作品中英文对照外文翻译文献

外文文献翻译原文+译文

(完整word版)外文文献及翻译doc

学前教育英文文献及翻译