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春节前后,吉安市遭遇到罕见的冰冻雨雪灾害天气,连续出现了低温、阴雨和雨夹雪,成为全省灾情最严重地区之一.特别是1月25日以后,出现了持续大范围的雨雪冰冻天气.冰冻损坏了市区的电网,压垮了树枝,封锁了道路和桥梁. 相似文献
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收集了2010年7月~2011年6月世界塑料工业的相关资料,介绍了2010~2011年世界塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚氯乙烯、聚苯乙烯、ABS树脂),工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚),特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮),通用热固性树脂(酚醛、不饱和聚酯树脂、环氧树脂、聚氨酯)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。 相似文献
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2003~2004年国外塑料工业进展 总被引:5,自引:0,他引:5
收集了2003年7月~2004年6月国外塑料工业的相关资料,介绍了2003年~2004年国外塑料工业的发展情况,提供了世界几大区域塑料的产量、增长率及所占份额,美国、德国、日本、韩国、法国、比利时、中国台湾、加拿大、巴西、西班牙等国家和地区的不同树脂的产量及消费量,各国、各地区塑料原料的产量、进出口量、国内消费量和人均消费量,日本塑料原料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。 相似文献
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萜类化合物具有可观的经济价值,但是目前的生产过程复杂、产量低。酿酒酵母甲羟戊酸途径为萜类化合物的合成提供直接前体,因此酿酒酵母细胞具有合成异源萜类化合物的天然优势。对酿酒酵母甲羟戊酸途径的清晰认识是对其进行有效利用的基础,本文从代谢途径、关键酶的特点和全局调控机制3个方面对该途径进行了介绍。从代谢途径的构建和优化、模块与底盘细胞的适配、模块构建及组装方式的角度概述了酿酒酵母细胞异源合成单萜、倍半烯萜、二萜、三萜类化合物的研究进展。指出实现酿酒酵母高效合成萜类化合物所需要解决的基础问题是对酿酒酵母甲羟戊酸途径进行更为全面了解和对萜类化合物的天然代谢途径进行明确解析;另外,合成生物学的进一步发展也将为此提供应用基础。 相似文献
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我公司回转窑规格为Φ4.0m×60m.窑内使用的耐火砖为镁铬砖、隔热尖晶石、蓝晶石和黏土砖以及硅莫砖.镁铬砖规格为(81×90×150×200)mm,其它耐火砖规格皆为(81×90×200×200)mm.尽管每个品种的砖品质相同,但由于在镶砌和使用过程中方法不同,寿命有长有短.通过多年实践,现总结如下. 相似文献
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In the present article, chitin from crab shell was systematically deacetylated using a NaOH treatment with control of the reaction time. The degree of deacetylation, monitored using solid-state NMR, revealed that the reaction was pseudo-first order. Based on this, swollen and NaOH-saturated particles are proposed as the reaction system. The weight loss of the partially saponified and neutralized samples after HCl hydrolysis increased linearly with the degree of deacetylation. The crystallinity of the samples was found to increase after acid hydrolysis. According to conductimetric titration, the surface charge density of the crystallites, after acid hydrolysis, was found to increase with base treatment time. The effect of surface charge on the formation of a chiral nematic phase, due to the rodlike nature of the crystallites, was explored. These results show that because the contribution of charged particles to the ionic strength was significant the double layer compression was affected, especially since the surface charge density was close to the Manning limit. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:373–380, 1997 相似文献
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目的研究大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌的耐药性变迁。方法对2007~2009年临床分离的大肠埃希菌(645株)、肺炎克雷伯菌(260株)和阴沟肠杆菌(150株),采用纸片扩散法进行体外药敏测定,并依据美国临床实验室标准化协会(Clinical and Laboratory Standards Institute,CLSI)规定的标准,分析3种肠杆菌科细菌的耐药性变迁。结果大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌对氨苄西林的耐药率均较高;对头孢他啶的耐药率低于头孢噻肟;与2007年比较,2008年和2009年对头孢吡肟的耐药率明显增长;未发现对亚胺培南耐药菌株的产生。结论细菌耐药性不断增强已成为临床治疗面临的重要难题,应从耐药监测、医院感染控制、合理使用抗生素等多方面努力,减少细菌耐药性的产生。 相似文献
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介绍了溶胶-凝胶法制备催化剂的3种主要方法:(1)将有机分子直接物理包容到陶瓷材料中;(2)通过与有机金属烷氧化物的共聚对陶瓷基体进行改性;(3)通过共聚形成2种或2种以上物质的基体复合物。并对3种方法进行了综述。 相似文献
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An important step in the formation of product from feed in a fluidized‐bed coker is the evolution of product and coke from layers of vacuum residue on the surfaces of heated particles and from liquid inside agglomerates of liquid and solid. In the present study, the yield of coke from Athabasca vacuum residue was measured using a reactor based on rapid induction heating of thin films of liquid feed on the surface of pieces of Curie‐point alloy. This approach allowed measurement of the yield of coke at pressures from 101–652 kPa, temperatures of 503 and 530°C, and reaction times from 10 to 240 s. When the liquid was reacted in thin films of ca. 20 µm, the effects of temperature and pressure on coke yield were insignificant. As the film thickness was increased to 120 µm, the yield of coke increased at all conditions. The yield of coke from thicker films was only sensitive to total pressure at 503°C reaction temperature, when the pressure was increased from 377 kPa to 652 kPa. Observable bubbling due to cracking reactions during coking was suppressed by increasing pressure, and the transition from quiescent liquid to bubbling liquid increased from circa 26 µm at 101.3 kPa to 78 µm at 652 kPa at 503°C. The bubbling transition was much less sensitive to pressure at 530°C, falling in the range from 22 µm to 43 µm as pressure increased from 101.3 to 652 kPa. These results suggest that the most important effect of pressure will be on the physical behaviour of liquid feed, due to its impact on bubble evolution from liquid inside agglomerates of liquid and solid particles. Depending on the liquid/solid ratio in an agglomerate, the formation of bubbles inside such a structure would make it weaker and easier to disperse on the fluidized bed reactor. 相似文献
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The objective of this study was to optimize the character of the unshrinkableness of wool fibers. A study of the processing of fibers of wool by an oxidative processing by performic acid was carried out by a complete factorial design to determine the most influential parameters of this study and then to optimize this process by the method of simplex. In parallel, a new ozone treatment was applied and a central composite design adapted to this protocol made it possible to identify the most influential parameters. This last type of processing has the advantage of being less polluting. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 535–547, 2003 相似文献
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过滤系数λ是表征深层过滤性能的重要参数,用试验的方法测定滤床过滤系数较为复杂。通过试验法和数学模拟法对不同粗细的滤料滤床进行研究,确定其λ的具体值,通过比较两者的结果发现,利用数学模拟法替代复杂的试验方法来确定实际滤床的过滤系数和预测运行状况是简便可行的。 相似文献
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Henda Zoghlami-Mosrati Andr Laurent Jean-Pierre Corriou 《Chemical Engineering Research and Design》2008,86(6):640
The new dispositions of the recent French law, called “Lois Risques” present some difficulties of application to qualify and quantify the new notion of dynamics of a hazardous process such as a thermal runaway. Many steady models predicting the thermal runaway (Semenov, Frank–Kamenetskii, Thomas, etc.) are proposed in literature. Due to their simplifying hypotheses, even if these models are widely used, they do not provide any information on the history of the self-heating of the system enabling to predict the necessary time to urgently react to a drift. The analysis of the transient thermal behaviour turns out to be necessary to complete the previous classical results, to estimate the profile of the adiabatic temperature rise and the time of induction for reaching the maximum adiabatic temperature and thus to better characterize the ability of the system to runaway, whose prediction fiability must be presently improved to respond to the new needs of the hazard study. The present work shows that the consideration of the influence of temperature on the heat transfer parameters and of more realistic boundary conditions during the numerical solution of the heat balances describing the storage behaviour allows us to better predict the criticity and the dynamics of appearance and of evolution of the runaway concerning the example of a cork storage. 相似文献
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The combustion of a shock-dispersed-fuel charge consisting of 1-g flake Al in 6.6-, 21.5-, and 40.5-liter bomb calorimeters
were investigated. Wall pressure histories were used to diagnose the effect of energy release due to turbulent mixing and
combustion of the explosion cloud with air. These effects lead to a factor of four increase in the peak quasistatic pressure
for the 6.6-liter chamber. Pressure decay was observed at late times and was ascribed to energy losses to the walls due to
radiation heat transfer.
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Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 6, pp. 121–125, November–December, 2006. 相似文献
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Kinetics of transesterification of soybean oil 总被引:11,自引:16,他引:11
Transesterification of soybean oil with methanol was investigated. Three stepwise and reversible reactions are believed to
occur. The effect of variations in mixing intensity (Reynolds number=3,100 to 12,400) and temperature (30 to 70°C) on the
rate of reaction were studied while the molar ratio of alcohol to triglycerol (6:1) and the concentration of catalyst (0.20
wt% based on soybean oil) were held constant. The variations in mixing intensity appear to effect the reaction parallel to
the variations in temperature. A reaction mechanism consisting of an initial mass transfer-controlled region followed by a
kinetically controlled region is proposed. The experimental data for the latter region appear to be a good fit into a second-order
kinetic mechanism. The reaction rate constants and the activation energies were determined for all the forward and reverse
reactions. 相似文献