化学专业英语结课论文
化学论文英文版
化学论文英文版Jun-Ke Wang, Ying-Xiao Zong, Xi-Cun Wang, Yu-Lai Hu, Guo-Ren Yue.Synthesisof N-benzothiazol-2-yl-amides by Pd-catalyzed C(sp2)-H functionalization[J]. CCL, 2015,26(11): 1376-1380Synthesis of N-benzothiazol-2-yl-amides byPd-catalyzed C(sp2)-H functionalizationJun-Ke Wang a,b,c, Ying-Xiao Zong a,b, Xi-Cun Wang a,b, Yu-Lai Hu a,b,Guo-Ren Yue aa Key Laboratory of Hexi Corridor Resources Utilization of Gansu Universities, College of Chemistry and Chemical Engineering, Hexi University, Zhangye 734000, China;b Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, China;c Gansu Engineering Laboratory of Applied Mycology, Hexi University, Zhangye 734000, ChinaReceived 11 May 2015, Received in revised form 29 June 2015, Accepted 1 July 2015,Available online 10 August 2015.E-mail addresses: wangxicun@;huyulai@Abstract: A catalytic synthesis of N-benzothiazol-2-yl-amides from1-acyl-3-(phenyl)thioureas was achieved in the presence of a palladium catalyst through the C(sp2)-H functionalization/C-S bond formation. This synthetic methodology can produce various N-benzothiazol-2-yl-amides in high yields with good functional group tolerance.Key words: Benzothiazole Pd-catalyzed1-Acyl-3-phenylthiourea C-H functionalization L-Proline1. IntroductionThe benzothiazole moiety is an important scaffold due to its widespread occurrence in bioactive natural products,pharmaceuticals, organic optoelectronic materials,and ligands for phosphorescent complexes [1-4]. In particular,substituted Nbenzothiazol- 2-yl-amides are an important class of heterocyclic compounds that exhibit a wide range of biological properties [5-9] such as ubiquitin ligaseinhibition [5],antitumor [6],antirotavirus infections [7],modulating the adenosine receptor [8, 9],and the nuclear hormone receptor [9]. For example,the N-benzothiazol-2- yl-cyclohexanecarboxamide,as a new anticancer drug,was selected as one of the most promising screening hit compounds (Fig. 1) [6]. The acylation reaction from2-aminobenzothiazole,one of the classical methods for the preparation of these molecules [5, 6],is known for the limited diversity of the commercially available starting materials. Furthermore,the preparation of 2-aminobenzothiazole also required the use of the toxic bromine.The past several years have witnessed the great progress in the development of the C-S bond formation promoted by transition metals,which can provide moreefficient,practical,and straightforward approaches to valuable sulfur-containing compounds [10, 11]. However,these methods have been mainly focused on the‘‘traditional’’ cross-coupling reactions of ArX (X = Cl,Br,I,OTf,and B(OH)2) and sulfides [12-39]. To achieve greener and more atomeconomic C-S bond formations,transition metal-catalyzed direct oxidative cross-coupling of C-H bonds and sulfides would be ideal [40-47].In our previous work,we have shown that N-benzothiazol-2-ylamides can be synthesized smoothly by Cu-catalyzed intramolecular cyclization of various substituted 1-acyl-3-(2-bromophenyl) thioureas [48]. This method can provide more diversiform Nbenzothiazol- 2-yl-amides through the carbon-heteroatom formation under relatively mild conditions and avoid the use of the toxic bromine. However,the drawback of this procedure is the limited diversity of the commercially available starting materials due to the use of substituted ortho-haloarylamines. In order to further extend the diversity of N-benzothiazol-2-yl-amides,we have recently demonstrated an efficient intramolecular cyclization of substituted 1-acetyl-3-(2-phenyl)thiourea catalyzed by iron through C-H functionalization [49]. This method can provide more diversiformN-benzothiazol-2-yl-amides under relatively mild conditions. However,the purification of the target compounds is challenging using the column chromatography or recrystallization,since it is inescapable to obtain 1-acetyl-3-phenylurea whose polarity is similar to that of 1-acetyl-3-(2-phenyl)thiourea. Recently,Doi’s group[46] reported a Pd-catalyzed synthesis of 2-substituted benzothiazoles via a C-H Functionalization reaction. Therefore,we envisioned that Pd-catalyzed cyclization of 1-acyl-3-(2-phenyl)- thiourea 1would represent a viable method for the formation and purification of substituted N-benzothiazol-2-yl-amides 2(Scheme 1).2. ExperimentalAll reagents were commercially available and used as supplied. Dimethyl sulfoxide (DMSO) was dried and distilled from calcium hydride. N,N-Dimethylformamide (DMF),toluene,DME and CH3CN were dried prior to use using standard methods. Unless otherwise stated,analytical grade solvents and commercially available reagents were used as received. Thin layer chromatography (TLC) employed glass 0.20 mm silica gel plates. Flash chromatography columns were packed with 200-300 mesh silica gel.All new compounds were characterized by IR,1H NMR,13C NMR and HRMS. The known compounds were characterized by 1H NMR, 13C NMR and HRMS. The IR spectra were run on a Nicolete spectrometer (KBr). The 1H NMR and 13C NMR spectra were recorded on a BRUKER AVANCEIII 400 MHz spectrometer. The chemical shifts (d) were given in parts per million relative to an internal standard tetramethylsilane. High resolution mass spectra (HRMS) were measured with a Waters Micromass GCT instrument and accurate masses were reported for the molecular ion (M+). Melting points were determined on a Perkin-Elmer differential scanning calorimeter and the thermometer was uncorrected.2.1. General procedure for the synthesis of1-acyl-3-arylthioureas [49, 50]To a 25 mL round-bottom flask equipped with a magnetic stirring bar was added acyl chloride (10 mmol),NH4SCN (15 mmol) and CH2Cl2 (20 mL),followed by PEG-400 (0.1 mmol). The mixture was stirred for approximately 3 h at room temperature. Aromatic amine (10 mmol) was added to the mixture and stirred for another 2 h at room temperature. The solvent was removed under reduced pressure to give the resulting residue as a solid,which was washed with water three times,to give the crude product.The analytical samples were obtained by recrystallization from C2H5OH in good yields ([4TD$DIF]88%-98%).2.2. General procedure for the synthesis ofN-benzothiazol-2-ylamides by aPd-catalysed C(sp2)-H functionalization reactionA round-bottom flask equipped with a stirring bar was charged with1-acyl-3-arylthioureas (1 mmol),PdCl2 (10 mol%),CuI (20 mol%),Cs2CO3 (2 equiv.),and L-proline (20 mol%) in 5 mL of DMSO. The mixture was stirred at 100 ℃for the indicated time in Table 2. After cooling to room temperature,the reaction mixture was extracted with ethyl acetate (10 mL × 3). The organic layers were combined,dried over Na2SO4 and concentrated under reduced pressure,and then purified by silica gel chromatography (acetone/petroleum ether = 1:4) to yield the desired product2.N-(4-Ethylbenzo[d]thiazol-2-yl)acetamide (2f): A gray solid (80% yield); mp:264-268 ℃; IR (cm-1): 3169.9,2990.1,2359.9, 1661.1,1550.4; 1H NMR (400MHz,CDCl3): δ 9.42 (s,1H),7.67 (dd, 1H,J = 6.3,2.9 Hz),7.27 (dd,2H,J = 4.4,1.9 Hz),3.04 (q,2H, J = 7.6 Hz),2.28 (s,3H),1.34 (t,3H,J = 7.6 Hz); 13C NMR (100 MHz,CDCl3): δ171.64(s),156.91 (s),146.45 (s),136.81 (s),131.98 (s), 125.25 (s),124.22 (s),118.92 (s),25.36 (s),23.51 (s),14.79 (s); HRMS calcd. for C11H12N2OS [M]+:220.0670; found [5TD$DIF]200.0678.N-(6-Fluorobenzo[d]thiazol-2-yl)acetamide (2 g): A white solid (94% yield); mp:224-231 ℃; IR (cm-1): 3207.8,3071.0,2983.9, 2360.4,1689.2; 1H NMR (400MHz,CDCl3): δ 7.70 (dd,1H,J = 8.9, 4.6 Hz),7.53 (dd,1H,J = 8.0,2.5 Hz),7.19 (td,1H,J = 8.9,2.6 Hz), 2.31 (s,3H); 13C NMR (100 MHz,CDCl3): δ 168.33 (s),160.93 (s), 158.50 (s),121.30 (d,J = 9.1 Hz),114.75 (s),108.09 (s),107.82 (s), 23.46 (s); HRMS calcd. for C9H7FN2OS [M]+: 210.0263; found 210.0256.3. Results and discussionWhile not commercially available,benzothioureas are stable and easilysynthesized [50, 51] from inexpensive starting materials in high yields on a multigram scale. Following Scheme 2,the synthesis of benzothioureas can be achieved in a straightforward manner starting from inexpensive aryl acid chloride and arylamines. Aryl acid chloride was treated with ammonium sulfocyanide in the presence of PEG-400in CH2Cl2,followed by the addition of arylamines,to obtain 1-arylacyl-3-phenylthiourea in good to excellent yields. This intermediate can be used directly without further purifications.In a preliminary experiment,we investigated the intramolecular C-S bond formation of 1-acetyl-3-phenylthiourea utilizing PdCl2 (20%) and a mild base (K2CO3,2 equiv.) in DMSO for 20 h at 100 ℃(Table 1,entry 1). However,the reaction almost failed to take place. Subsequently,we screened several metal salts as cocatalysts, includingAlCl3,CuCl2,Cu(OAc)2,CoCl2,NiCl2,FeCl3,CuI, and CuCl,and found that the addition of CuI considerably enhanced this reaction (Table 1,entries 2-8). However,the desired yield was still not obtained. Surprisingly,when Doi’s condition was used,the yield was still very low (42%) (Table 1,entry 9). Generally,the choice of the ligands is important for the reaction catalyzed by the metal,which prompted us to explore the effect of several bidentate ligands. We carried out the reaction of 1-acetyl-3-phenylthiourea by screening these ligands,such as 1,10-phenanthroline,β-keto esters,β-diketones,andL-proline. (Table 1,entries 10-13),and we were pleased to find that the use of these ligands can notably improve the yield of the product under the same conditions,and that L-proline proved to be the best among an array of ligands tested (Table 1,entry 14). When the amount of CuI and PdCl2 was decreased to 20 mol% and 10mol%,respectively,the catalytic activity was maintained (Table 1,entry 14). Furthermore,we also investigated other bases (Cs2CO3 and K3PO4) (Table 1,entries 15- 16),solvents (DMF,DME,and toluene) (Table 1,entries 17-19) and reaction time (Table 1,entries 20-21). When only CuI was used in this cyclization,no reaction can take place (Table 1,entry 22). Thus, the optimized reaction conditions are as the follows: substrate (1 mmol),PdCl2 (10 mol%),CuI (20 mol%),Cs2CO3 (2 equiv.), L-proline (20 mol%) in DMSO (4 mL) within 8 h at 100 ℃.In response to this encouraging result,we used a range of substituted1-acetyl-3-(phenyl)thioureas to investigate the scope and limitation of this reaction. The corresponding products were obtained in excellent yields (88%-98%). The results obtained under the optimized conditions are listed in Table 2. Initially,the substituents of phenyl were screened. The results demonstrate that little effect of the substituted groups on the benzene ring was observed for this transformation.Furthermore,substituents at different positions of the phenyl ring do not significantly affect the efficiency (Table 2,entries 1-8). It is noteworthy that the halosubstituted benzenes survived leading to halo-substituted products,which can be used for further transformations (Table 2, entries 2,7,8 and 11). In order to make the new Sankyo investigational drugs,the R group was selected as a cyclohexyl to give the corresponding products (Table 2,entries 10-12).Although extensive studies on reaction mechanism have not yet been carried out,the proposed mechanism can be proposed according to the similar palladium-catalyzed processes [51] (Scheme 3). 1-Acetyl-3-(phenyl)thiourea was converted to the thioenolate in the presence of Cs2CO3. Pre-association of the sulphur atom in the thioenolate to Pd(OAc)2 facilitates the orthopalladation process with the concomitant release of chloride ion. The formation of the six-membered palladacycle and the subsequent reductive elimination leads to N-benzothiazol-2-yl-amide and Pd(0). The Pd(0) species are reoxidized to Pd(II) by CuI,thus completing the catalytic cycle.4. ConclusionIn conclusion,we have achieved an efficient intramolecular cyclization of substituted 1-acetyl-3-(2-phenyl) thioureas catalyzed by palladium(II) catalysts through C(sp2)-H functionalization. This method can provide more diversiform N-benzothiazol-2-yl-amides efficiently and quickly in high yields under relatively mild conditions. The combination of the generality with respect to the substrate scope and facile accessibility to the starting materials may generate numerous synthetic possibilities. Further mechanistic analysis of these reactions will be the subject of future work.AcknowledgmentsThis work was supported by the National Natural Science Foundation of China (Nos. 21462016,21262010),Natural Science Foundation of Gansu Province and the Advanced Research Fund of Jinchuan Group Co.,Ltd.References[1] R.S. Keri, M.R. Patil, S.A. Patil, S. Budagumpi, A comprehensive review in currentdevelopments of benzothiazole-based molecules in medicinal chemistry, Eur. J.Med. Chem. 89 (2015) 207-251.[2] A. Rouf, C. Tanyeli, Bioactive thiazole and benzothiazole derivatives, Eur. J. Med.Chem.97 (2015) 911-927.[3] A.G. DiKundar, G.K. Dutta, T.N. Guru Row, S. Patil, Polymorphism inopto-electronic materials with a benzothiazole-fluorene core: a consequence of high conformational flexibility of p-conjugated backbone and alkyl sidechains, Cryst. Growth Des. 11 (2011) 1615-1622.[4] T. Girihar, W. Cho, Y.H. 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化学化工专业英语论文
橡胶是一种伸缩性优异的弹性体，但其综合性能并不令人满意，生产黑的加入使得制品均为黑色，且档次不高。而纳米SiO2在我国的问世为生产出色彩新颖、性能优异的新一代橡胶制品奠定了物质基础。
在普通橡胶中添加少量纳米SiO2后，产品的强度、耐磨性和抗老化性等性能均达到或超过高档橡胶制品，而且可以保持颜色长久不变。纳米改性彩色三元乙丙防水卷材，其耐磨性、抗拉强度、抗折性、抗老化性能均提高明显，且色彩鲜艳，保色效果优异。彩色轮胎的研制工作也取得了一定的进展，如轮胎侧面胶的抗折性能由原来的10万次提高到50万次以上，有望在不久的将来，实现国产汽车、摩托车轮胎的彩色化。
Key words:mono-dispersed; silica;Zeta potential; stability
第1章 前言
二氧化硅无机粉体在光、热、电、磁等方面具有奇特性能，得到广泛应用，但在许多生产加工工艺中，均需要粉末均匀且稳定地分散于液相介质中，近年来，由于新型陶瓷、铜版纸以及水性涂料的发展，其中对无机填料的细度和水中分散性要求日益提高，从而迫切要求无机填料能在水中十分均匀地稳定分散，甚至可以认为是工艺成功的关键所在[1]，但超细粉体比表面积大、表面能高易使粒子相互吸引而具有不稳定的倾向，粒子产生团聚影响其应用效果。而电位的大小是衡量胶体粒子稳定性的重要参数。Zeta电位的重要意义在于它的数值与胶态分散的稳定性相关。Zeta电位是对颗粒之间相互排斥或吸引力的强度的度量。分子或分散粒子越小，电位(正或负)越高，体系越稳定，即溶解或分散可以抵抗聚集。反之，Zeta电位(正或负)越低，越倾向于凝结或凝聚，即吸引力超过了排斥力，分散被破坏而发生凝结或凝聚[2]。SiO2悬浮液的稳定性，与其在水中的电动性质密切相关。粉体表面的电位绝对值高，表明粉体表面电荷密度高，颗粒间的排斥力大，粉体易于稳定分散悬浮。电位的主要用途之一就是研究胶体与电解质的相互作用。由于许多胶质是带电的，特别是那些通过离子表面活性剂达到稳定的胶质，它们以复杂的方式与电解质产生作用。与它表面电荷极性相反的电荷离子（抗衡离子）会与之吸附，而同样电荷的离子（共离子）会被排斥。因此，表面附近的离子浓度与溶液中与表面有一定距离的主体浓度是不同的。靠近表面的抗衡离子的积聚屏蔽了表面电荷，因而Zeta电位降低。Zeta电位的测量使我们能够详细了解分散机理，它对静电分散控制至关重要。对于酿造、陶瓷、制药、药品、矿物处理和水处理等各个行业，Zeta电位是极其重要的参数。
化学工程英语作文
化学工程英语作文Chemical engineering is a discipline that plays a pivotalrole in the development and advancement of modern society. It involves the application of physical science, biology, and chemistry, along with math and economics, to design, develop, and produce useful products and services. This essay will explore the various ways in which chemical engineering has shaped our world, from the pharmaceutical industry to environmental sustainability.Firstly, chemical engineering has been instrumental in the production of pharmaceuticals. The development of life-saving drugs and therapies is heavily reliant on the expertise of chemical engineers who work to create and refine the chemical processes that produce these medications. They are also involved in the design of equipment and facilities that ensure the safe and efficient production of these vital compounds.Secondly, the field of chemical engineering has made significant contributions to the energy sector. Engineers in this field are at the forefront of designing and optimizing processes for the production of fuels, including the development of cleaner and more sustainable energy sources. This includes the advancement of biofuels, solar energy, and other renewable resources, which are crucial in the global shift towards a greener economy.Moreover, chemical engineering is essential in the food and beverage industry. It is responsible for the development of processes that ensure the quality, safety, and longevity of food products. This includes the preservation techniques, packaging innovations, and the development of additives that enhance flavor and shelf life without compromising health.In addition to these areas, chemical engineering is also critical for environmental sustainability. Engineers work on solutions to reduce pollution, manage waste, and develop processes that minimize the environmental impact of industrial operations. This includes the treatment of wastewater, the development of more efficient chemical processes, and the creation of materials that are biodegradable or recyclable.Furthermore, the role of chemical engineering extends to materials science, where it is used to create new materials with specific properties for various applications. This includes the development of polymers for use in medical devices, the creation of stronger and lighter materials for aerospace engineering, and the synthesis of advanced materials for electronics.In conclusion, chemical engineering is a multifaceted discipline that has far-reaching implications for the betterment of society. From healthcare to energy, from food production to environmental protection, the contributions of chemical engineers are integral to the progress and well-being of our modern world. As we continue to face newchallenges, the innovative solutions that chemical engineering can provide will be more important than ever.。
关于化学的专业英语小作文
关于化学的专业英语小作文Chemistry is a fascinating science that delves into the composition and properties of matter. It is the study of how elements interact and transform, revealing the secrets of the universe at a molecular level.In the realm of chemistry, the periodic table stands as a testament to the systematic organization of elements. Each element has its unique atomic structure, and understanding these structures is key to predicting reactions and behaviors.Experimentation is at the heart of chemistry. It is through the meticulous design and execution of experimentsthat we uncover new compounds, reactions, and insights intothe world of matter. The lab is a place of discovery, where hypotheses are tested and knowledge is expanded.Chemical reactions are the cornerstone of this science. They can be simple or complex, exothermic or endothermic. The balance of reactants and products, governed by the law of conservation of mass, is a fundamental principle that guides our understanding.Analytical chemistry is the branch that focuses on the detection, identification, and quantification of chemical substances. It plays a crucial role in various industries,from pharmaceuticals to environmental monitoring, ensuring safety and quality.Organic chemistry, a sub-discipline, deals with carbon-containing compounds. The complexity of organic molecules and their vast array of reactions make it a rich field for innovation and the development of new materials and drugs.Biochemistry, another branch, explores the chemical processes within living organisms. It is the intersection of biology and chemistry, where the understanding of enzymes, proteins, and metabolic pathways is crucial for advancements in medicine and nutrition.Chemistry education is vital for nurturing the next generation of scientists. It equips students with the analytical skills and knowledge base necessary to contribute to scientific research and technological innovation.In conclusion, chemistry is an ever-evolving field with applications that touch every aspect of our lives. From the medicines we take to the materials we use, the study of chemistry is integral to the progress of human civilization.。
化工专业英语写作范文
化工专业英语写作范文Title: The Evolution and Importance of Chemical Engineering: A Global Perspective.Chemical engineering, often referred to as the "mother of all engineering disciplines," has played a pivotal role in the advancement of technology and industrialization. Its impact is felt across multiple sectors, including energy, healthcare, environmental protection, and more. In this article, we delve into the evolution of chemical engineering, its current significance, and its future prospects.Evolution of Chemical Engineering.The roots of chemical engineering can be traced back to the Industrial Revolution, when the need for efficient and sustainable production methods arose. Initially, the field was primarily focused on the optimization of processes in the chemical industry, such as the production offertilizers and dyes. However, as technology advanced, the scope of chemical engineering broadened to include areas like biochemistry, environmental engineering, and nanotechnology.One of the most significant milestones in the evolution of chemical engineering was the development of the principles of reaction engineering in the early 20th century. This marked a shift from a reliance on empirical methods to a more rigorous and systematic approach, based on the principles of physics and chemistry. This development laid the foundation for the design and optimization of chemical reactors, which are crucial in the production of various chemicals.Another key development was the integration of computers into chemical engineering in the later part of the 20th century. This integration enabled engineers to model and simulate complex chemical processes, thus predicting their behavior more accurately. Computer-aided design (CAD) and computer-aided manufacturing (CAM) tools also revolutionized the design and fabrication of chemicalplants, making the process more efficient and cost-effective.Current Significance of Chemical Engineering.Today, chemical engineering is at the forefront of addressing many of the world's most pressing challenges. For instance, it plays a crucial role in the development of sustainable energy solutions. Chemical engineers are involved in the research and development of efficient solar cells, batteries, and fuel cells, as well as in the optimization of biofuel production processes.In healthcare, chemical engineering has madesignificant contributions to the development of drugs and therapies. By manipulating molecules at the nanoscale, engineers are able to create targeted drugs that are more effective and have fewer side effects. They are also involved in the design of medical devices and the optimization of bioprocessing techniques for tissue engineering and regenerative medicine.Moreover, chemical engineering is essential in addressing environmental challenges. Engineers are working to develop more efficient waste treatment and recycling methods, as well as to mitigate the impact of industrial processes on the environment. They are also involved in the research and development of sustainable materials that can replace traditional, environmentally harmful ones.Future Prospects of Chemical Engineering.The future of chemical engineering looks bright, with numerous opportunities for innovation and growth. One area that is expected to witness significant advancements is biotechnology. With the advent of synthetic biology and genome editing tools like CRISPR-Cas9, chemical engineers will be able to design and engineer cells and organisms with enhanced functionalities. This could lead to the development of novel bioproducts, such as bioplastics and biofuels, that are more sustainable and environmentally friendly.Another area of potential growth is nanotechnology.Chemical engineers are exploring the use of nanomaterialsin various applications, including drug delivery, energy storage, and environmental remediation. The uniqueproperties of nanomaterials, such as their large surface area and enhanced reactivity, make them ideal foraddressing many of the challenges faced by the chemical industry.Lastly, the integration of digital technologies, suchas artificial intelligence (AI) and the Internet of Things (IoT), is expected to transform chemical engineering. These technologies can be used to optimize processes in real-time, predict and prevent failures, and improve safety and sustainability. By leveraging the power of data analytics and predictive modeling, chemical engineers will be able to make more informed decisions and develop more efficient and cost-effective processes.In conclusion, chemical engineering has come a long way since its inception and continues to play a pivotal role in addressing the world's most pressing challenges. As we look to the future, it is exciting to imagine the innovativesolutions that chemical engineers will develop and the impact they will have on society.。
浅谈化学专业英语论文写作
浅谈化学专业英语论文写作引言在化学专业中，英语论文的写作是不可避免的任务。
然而，许多学生在写作上遇到了各种挑战，并且有些人往往对英语论文的写作感到非常困难。
本文将探讨一些基本的写作技巧，以帮助化学专业学生更加成功地编写英语论文。
选择主题在开始写作之前，第一步是选择一个主题。
主题的选择应该基于以下因素：•你的兴趣和知识领域•研究领域和前沿•当前的热点问题你应该选择一个你感兴趣的主题，以便你对于该主题有足够的知识背景和深入的理解。
此外，重要的是要寻找一个有趣和未解决的问题，以此来激起读者的兴趣。
写作流程计划在开始写作之前，你应该先拟定一个计划或者提纲。
这个计划或提纲将指导你的写作，并使你能够更好地控制论文的整体结构和内容。
以下是一些你应该考虑的问题：•你的论文将会有几个主要章节？•每个章节的内容是什么？•你将使用哪些方法和技术？•你将引用哪些参考文献？计划应该清晰、有条理、详细。
一个好的计划将为你后续的写作提供有力的支持。
写作在你拟定好计划之后，就可以开始写作了。
以下是一些你应该记住的关键问题：•专业术语和概念应该得到准确且恰当的使用。
•句子应该简短、有力，有清晰的结构，注重逻辑，避免冗余。
•用字应该准确、规范，注意拼写错误。
•确认你的论点是否有证据支持，并用相应的数据和例子来加强支持。
•合理引用参考文献，遵守学术规范。
修订完成初稿后，你需要进行多次修订，以确保最终成稿的准确性和流畅性。
以下是一些你应该记住的关键问题：•确保句子通顺，表达清晰，用语考虑规范和准确性。
•前后的章节间应有明显的逻辑关系，文章应有足够的连贯性。
•纠正语法和拼写错误。
•根据编辑审阅的反馈意见进行修改。
语言技巧在化学专业英语论文写作过程中，正确使用语言技巧和单词非常重要。
以下是一些你应该掌握的用法：•使用恰当的专业术语和概念，可以通过文献综述理解其用法和常用表达方式。
•避免使用过多复杂的句子结构和嵌套。
•尽量使用简单的词语和句子进行表述，利于理解。
化工专业英语论文写作
4.Experimental
• The Cu2O-doped SiO2 composite films were prepared by a simple method at room temperature and in ambient pressure.
5 .Results and discussion
2 . Keywords
Composite materials; Nanocomposites; Thin
films; γ-irradition
3. Introduction
• Nanometer-sized ultrafine particles of metals and semiconductors display many intriguing properties including optical nonlinearity, specific heat and magnetism properties , which are quantitatively and qualitatively different from their respective bulk materials. In the past decade, much attention has been paid to the study of composite of nanometer-particles embedded in various matrixes from the viewpoint of scientific interest and their applications .
7 .References
• [1] K. Tanaka, N. Minamikawa, Appl. Phys. Lett. 86 (2005) 12. • [2] W.H. Koo, S.M. Jeoung, S.H. Choi, Thin Solid Films 468 (2004) 28. • [3] B. Ghosh, S. Banerjee, D. Chakravorty, J. Nanosci. Nanotechnol. 4 (2004)849. • [4] H.G. Guo, X.M. Zhang, M.H. Cui, Mater. Res. Bull. 40 (2005) 1713. • [5] E.M. Vogel, J. Am. Ceram. Soc. 72 (1989) 719. • [6] C. Flytzanis, F. Hache, M.C. Klein, D. Ricar, P. Rossingnol, Prog. Opt. 29(1991) 321. • [7] W.P. Cai, L.D. Zhang, Phys. Condens. Matter 8 (1996) 591. • [8] T. Hayakawa, S.T. Slevan, M. Nogami, Appl. Phys. Lett. 74 (1999) 1513. • [9] H. Amekura, N. Umeda, Y. Sakuma, Appl. Phys. Lett. 87 (2005) (Art. No.013109).
以化学为主修的英语作文
以化学为主修的英语作文Chemistry is a subject that has always fascinated me. From understanding the structure of atoms to exploring the different types of chemical reactions, there is so much to learn and discover. In this essay, I will discuss the importance of chemistry and how it has impacted the world around us.Chemistry plays a crucial role in our everyday lives. It is involved in everything we do, from the food we eat to the air we breathe. By studying chemistry, we can better understand the composition of substances and how they interact with each other. This knowledge is essential for various industries, such as pharmaceuticals, agriculture, and environmental science.In addition, chemistry has led to numerous technological advancements that have revolutionized the way we live. For example, the development of new materials and compounds has paved the way for innovations in medicine, electronics, and energy production. Without chemistry, many of the products and technologies we rely on today would not exist.Furthermore, chemistry has also played a significantrole in addressing global challenges, such as climate change and pollution. By studying chemical processes and their impact on the environment, scientists can develop sustainable solutions to reduce our carbon footprint and preserve natural resources. This is crucial for the future of our planet and the well-being of future generations.Overall, chemistry is a fascinating and essential subject that has far-reaching implications in our world. By studying chemistry, we can gain a deeper understanding of the natural world and use that knowledge to create positive change. I am grateful for the opportunity to learn about this incredible field and look forward to applying my knowledge to make a difference in the world.化学是一门让我着迷的学科。
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化学专业英语结课论文摘要;化学科学技术发展战略更加贴近社会和经济需求, 生态环境恶化严重干扰可持续发展。
化学科学技术活动总目标是:提供安全的能量、化学品和制造品, 既不会不可逆转地消耗地球上的稀有原料, 也不会产生有害物质污染地球;发现和创新新物质, 研究物质的化学和物理转化, 检测鉴定各种尺度物质的结构和性质;理论化学、计算化学和过程系统工程的创新应用, 及其与生物学、医药、电子学、信息学协同并在材料、医药、能源、信息、环境以及国家安全领域激励人心的应用。
科学研究和人才培养都充满学科交叉。
关键词:化学科学技术;人与自然协调;可持续发展;创新Chemical Science and Technology and Sustainable DevelopmentAbstract:Development strategy of chemical science and technology depends more and more on the demand of society and economic development nowadays, while the environment deterioration seriously interferes the sustainable development.So the chief objectives of chemical science and technology are:to provide safe energy, chemicals and products;not to consume the rare materials on earth irreversibly;not to produce harmful wastes to pollute the environment;to discover and innovate new compounds;to make research on the chemical and physical transformation of substances;to detect and determine the structures and the properties of materials of various sizes;and to make the innovative application of theoretical chemistry, computer chemistry and processing systematic engineering and their synergies with biology, pharmaceutics, electronic sand informatics for the application in the fields of materials, pharmaceutics, energy resources, information, environment and national security .Subject intersection always penetrates in scientific research and talent cultivation.Key words:chemical science and technology;harmony of human and nature;sustainable development; discover and innovate[1]1 “教”之道1.1 与时俱进，科学合理安排教学内容材料化学的知识面很广，相应的《材料化学专业英语》既要综合非金属材料又要涵盖高分子材料，既要涉及单一材料，又要涉及复合材料，既要涉及结构材料又要涉及功能材料，此外还要与大学基础英语相衔接又要为学生以后毕业论文中摘要的书写及以后研究生深造的英语打好基础，覆盖面广，且各方面的知识更新的很快!所以在教学内容安排上，必须科学合理，与时俱进![2]1.2 走人与自然协调的可持续发展之路通过几年的教学改革,学生对以专业阅读为基础,强调培养专业英语的实际应用能力和学术交流能力的化学专业英语课程的教学内容、培养方式普遍认可。
教学改革获得了绝大多数学生的肯定。
[3]2 培养师范生教学科研能力的必要性2.1 英语课程改革要求师范生具有初步的教学科研能力中小学英语新课程2001年开始试行,2003年在全国范围内推广。
与以往的英语课程比较,新课程无论在课程性质还是在基本理念或设计思路上都有了很大的变化。
如新课程标准把培养学生的综合语言运用能力作为基础教育阶段英语课程的总体目标,并倡导“任务型”教学途径,提出了形成性评价的建议,为有效实施新课程提供了实施向导和准则。
同时,新课程标准也对中小学英语教师的素质提出了更高的要求。
新课标指出“教师应依据课程的总体目标并结合教学内容,创造性地设计贴近学生实际的教学活动,吸引和组织他们积极参与”。
教师还应该做到“准确把握本课程标准的理念、目标和内容,运用教育学和心理学理论,研究语言教学的规律。
……要根据教学目标、学生的需要以及当地客观条件,积极地和有创造性地探索有效的教学方法;不断对自己的教学行为进行反思,努力使自己成为具有创新精神的研究型教师”。
[4]2.2 重点及难点基础英语要求学生能从“听、说、读、写、译”五个方面提高学生的英语水平和能力。
化学专业英语也同样要求学生能在这五个方面全面提高英语的实际运用能力,但侧重点和难点却和基础英语阶段有所区别。
该课程的重点是帮助学生掌握科技英语特殊的句法和文风(如,科技英语中较多使用长难句、省略句、强调句、倒装句、被动句、插入语、虚拟句等),掌握化学专业英语的构词规律(如专业词汇的词源、词根、词缀),学习化学专业领域内英语与汉语之间的翻译技巧,学习英语在化学专业领域的交际技能(包括口头交流和书面交流的技能),拓展学生在化学领域实际运用英语的能力。
[5]3 化学专业英语的存在的问题一直以来，对学生自主学习的研究越来越多。
学习化学专业英语也要有新的方法方式才能激发他们的兴趣，调动学习自主性,那样课堂教学就会事半功倍。
有人曾对非英语专业大学生课外英语自主学习的现状调查与分析，结果显示，近半数学习者的学习动机是属于工具性动机，也就是为了获得某种实用的、具体的汇报，比如为了毕业后好找工作等。
另外,化学化工专业英语的特点之一是专业术语多、合成新词多、前后缀多、缩略词多。
例如hemi-,一半，hemiacetal半缩醛；hetero-其他的，不同的，异；heteroaromatic compound芳香杂环化合物；heterocatalysis非均相催化，异相催化；homo-相同的，homogeneous同类的。
绝大多数化学专业词汇是由一些基本的词根、词缀组合构成的，所以掌握了化学化工专业英语中常用的拉丁语和希腊语词根、词缀及必要的构词知识，就等于是找到了一把打开科技英语专业词汇库的钥匙。
[6]4 结束语综上所述,化学专业英语学习是基础英语学习的延伸,是基础英语与化学专业知识的结合与实践,是提高英语应用能力的重要环节。
只有学习和掌握化学专业英语词汇规律、语法特点和表达方式特点并在实践中加以应用,才能提高专业英语综合能力。
[7]综上所述，化学专业英语学习是基础英语学习的延续，是基础英语与化学专业知识的有机结合与实践开展好化学专业英语教学不仅需要有合适的教材，还必须根据学生的实际情况进行教学理念和教学方法的改革教学实践证明，遵照规律教学，合理安排教学内容，完善教学方法，适时给予学生心理引导，实现教学相长是提高教学质量，营造宽松活跃的课堂氛围的有效手段。
[8]考核测试是鉴定学生能力水平“评价教学质量和评估教学效果的重要手段”它有助于学生知识的巩固和提高。
并为教师的教学提供反馈信息。
帮助教师及时了解教学效果，改进教学方法，提高教学质量。
因此，应当打破原有专业英语单一的笔试考核模式，增加英语口语运用能力的考核权重“采取灵活有效的考核方式，将学生平时课堂发言”分组讨论时的表现纳入期末成绩计算中去，并在期末考试时加设口语运用能力考核环节。
[9]在化学专业英语的学习过程中，掌握构词规律，词汇的变换以及根据上下文选择词义能够大大扩充词汇量。
此外，还应该注意对比形似词的意思，体会书面语和口语用词的差异，成对地记忆反义词等。
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2013 International Conference on Education and Teaching ，2013，92-92.[7] 黄正玲.化学专业英语学习策略探讨[A].海南广播电视大学学报,2009,4:3-3.[8] 杜攀.化学专业英语教学初探[A].江苏教育学院学报(自然科学),2011,27(2):65-65.[9] 孙丽萍,赵辉.化学专业英语教学方法的改进[A].长春工业大学学报(高教研究版), 2014,35(1):59-59.[10] 杨珊，王鹏.化学专业英语词汇学习技巧研究[A].广州化工,2013,41(21):155-155.。