共查询到20条相似文献,搜索用时 0 毫秒
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该文对氯氟烃(CFCs)替代物的开发方法、发展现状进行了介绍。目前,开发出的CFCs替代物包括氢氯氟碳(HCFCs)、氢氟烃(HFCs)和氢氟烯烃(HFOs)。其中,HFOs环境性能优异,可在制冷和发泡领域实现对HFCs的替代。总结了HFOs的主要合成路线,并指出最佳的产业化路线。展望了CFCs替代物的未来发展趋势,由于HFOs的核心专利被国外发达国家所垄断,而且HFOs存在二次污染和易燃的风险,同时HFOs类物质的性能难以满足精密清洗、高端芯片先进制造、高压电器绝缘等领域的使用要求,因此,今后的研究重点在于,开发满足国家重大战略需求的新一代替代物,实现诸多领域CFCs的精准替代。 相似文献
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Mauro Banchero 《Coloration Technology》2013,129(1):2-17
Supercritical fluid dyeing is an interesting alternative to the conventional aqueous process because of its environmental benefits. The aim of the paper is to provide the reader with an up‐to‐date overview of this subject, covering various aspects, such as the solubility and equilibrium partitioning of the dyes, mass transfer phenomena and solvent–polymer interactions occurring during coloration, up to the most recent reports on the technology of the dyeing process. Even though the best results have been obtained in the coloration of synthetic textiles, particular attention is given to the dyeing of natural textiles, which is, at the moment, the limiting step of this technology. 相似文献
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Directed evolution, the laboratory process by which biological entities with desired traits are created through iterative rounds of genetic diversification and library screening or selection, has become one of the most useful and widespread tools in basic and applied biology. From its roots in classical strain engineering and adaptive evolution, modern directed evolution came of age 20 years ago with the demonstration of repeated rounds of polymerase chain reaction (PCR)‐driven random mutagenesis and activity screening to improve protein properties. Since then, numerous techniques have been developed that have enabled the evolution of virtually any protein, pathway, network, or entire organism of interest. Here, we recount some of the major milestones in the history of directed evolution, highlight the most promising recent developments in the field, and discuss the future challenges and opportunities that lie ahead. © 2013 American Institute of Chemical Engineers AIChE J, 59: 1432–1440, 2013 相似文献
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Keith Parton 《Coloration Technology》1997,113(12):341-343
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回顾了化学反应工程学科和相关工业重要贡献的发展历史,提出以"物质的传递与转化"、"能量的传递与转化"和"信息的传递与转化"所组成的"三传三转"作为化学工程学科范式的新解读模式;强调了多尺度研究对于理解反应工程复杂问题的重要意义,计算技术的发展大大促进了反应工程理论的进步;从学科交叉和化工前沿角度探讨了反应工程新的发展方向,尤其展望了大型化煤化工、大规模天然气(页岩气)利用等将为中国的反应工程发展带来更为优越的国际领先契机,也是未来反应工程的任务和挑战。 相似文献
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J. H. Hetrick 《Journal of the American Oil Chemists' Society》1969,46(2):A58-A62
The history of substitute dairy products and their impact on the market is reviewed. The present status of filled and imitation
milk products is discussed from the flavor acceptance, economic, legal and nutritional standpoints. Comments on some factors
which will affect the future growth potential of these products, such as Consumer acceptance, economics, proposed legislation
with respect to compositional, nutritional and labeling requirements and industry attitude toward marketing of these products
are given.
Presented at a meeting of North Central Section of the American Oil Chemists’ Society, September 18, 1968. 相似文献
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Wilbur S. Mardis 《Journal of the American Oil Chemists' Society》1984,61(2):382-387
Rheological or flow properties have important implications in many and diverse applications. Often, an additive is used to
impart the desired flow behavior. Among these, organoclay products, formed by the reaction of organic cations with smectite
clays, are the most widely used additives for solvent-based coatings. The cation— usually a quaternary ammonium salt—used
will influence the performance of the resultant organoclay. Criteria to consider in the choice of a cation are molecular size,
compatibility with the fluid in which the organoclay is to be used, stability and reactivity. To form a stable organoclay
product, the organic cation must contain at least one long-chain alkyl group. Othr groups attached to the cation may be divided
into two categories: “filler” groups serve to complete the tetrahedron around the nitrogen, whereas “active” groups contribute
beneficially to the performance of the organoclay. Our study of the structure/property relationships has led to the development
of new additives described here. These are superior, particularly in terms of use, while providing the same excellent rheological
control offered by earlier additives. 相似文献
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Periodic mesoporous organosilicas (PMOs) represent an exciting new class of organic-inorganic nanocomposites targeted for a broad range of applications such as catalysis and sensing, separations, and microelectronics. Their hallmark is the presence of organic bridging groups incorporated into the channel walls of an ordered nanoporous structure, which represents a useful tool to finely tune the chemical and physical properties of the materials. We discuss the history of the discovery and development of the PMOs emphasizing the most important recent advancements regarding compositions and structures, morphologies, and properties. Furthermore, we present an outlook about the promising future perspectives of PMOs that result from the latest developments in this field. 相似文献
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Against the background of long-term availability of natural gas, its present technology and future prospects are described. Particular emphasis is put on the oxidative coupling of methane to C2+ hydrocarbons: (1) Catalyst development, activity, selectivity and deactivation as well as reactor operation are discussed; (2) a tentative process scheme is put forward and its economics evaluated with respect to ethylene production. 相似文献
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I. P. Parkin M. V. Kuznetsov 《International Journal of Self-Propagating High-Temperature Synthesis》2008,17(4):266-274
The United Kingdom has played a small but significant role in the development of SHS. Parkin and Kuznetsov have studied the
formation of complex oxides in external fields. Wood and Christanthou have studied the formation of intermetallic compounds
and refractory materials by SHS. Perry, Thompson, and Green have made contributions to the synthesis of materials by solution
phase auto-combustion reactions. The UK has also made contributions to the theory of SHS and the monitoring of SHS reactions
by time resolved X-ray, neutron, and thermal imaging studies. The UK has been at the forefront in the development of a sub-class
of SHS reactions termed solid state metathesis.
Presented at the International Conference on Historical Aspects of SHS in Different Countries, October 22–27, 2007, Chernogolovka, Moscow, Russia. 相似文献
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Munira Zainal Abidin Maria Paula Junqueira‐Gonçalves Vitaliy V Khutoryanskiy Keshavan Niranjan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2017,92(11):2787-2798
Chitin is, after cellulose, the most abundant organic natural polysaccharide on Earth, being synthesized as a dominant component in the exoskeletons of crustaceans, among other sources. In the processing of seafood for human consumption, between 40 and 50% of the total raw material mass is wasted, causing a significant problem for the environment owing to its slow degradation. Efforts to find uses for chitin derivatives, particularly their oligomers, have intensified since these chemicals are highly functional and offer a wide range of applications, especially as antimicrobial agent. As a consequence, some adjunct treatments, either chemical or physical in nature, have been employed to assist acid and enzymatic hydrolysis. This work provides a detailed review of the methods employed to intensify the formation of chitin oligomers, particularly focusing on the adjunct treatments used (microwave, ultrasonication, steam explosion and gamma irradiation), and an evaluation of the yield and characteristics of the oligomers formed. Adjunct treatments are more suitable for enzymatic hydrolysis since these treatments modify the chitin structure, and enhance the hydrolysis rate and yield of the oligomers, under milder reaction conditions. For future research, it would be worth trying pre‐treatments like the application of high‐pressure to chitin in order to lower its crystallinity. © 2017 Society of Chemical Industry 相似文献