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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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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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《日用化学品科学》编辑部 《日用化学品科学》2008,31(6)
2006年12月7日~2006年12月8日化妆品化学家年会在美国纽约举行,该年会为化学品供应商提供了参与REACH法规的机会.REACH法规的实施引起了业界的广泛关注,来自世界各地的著名化学品及化妆品公司对REACH法规的实施所带来的一些问题,以及新原料、新技术进行了交流.会议主要对就REACH法规、制造及规模化和神经美容品等方面展开了研讨. 相似文献
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The crystalline structure of a number of random polymers of perfectly alternating l-olefins/carbon monoxide aliphatic polyketones has been studied by wide angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and Raman spectroscopy. From previous studies, WAXS, Raman and DSC have shown to be suitable techniques for the characterisation of the two crystalline polymorphs, α (denser) and β, detected in ethene/carbon monoxide (ECO) and in ethene/propene/carbon monoxide (EPCO) polymers. In this paper for the first time, polyketones with butene and hexene as the second olefin are reported. It was found that the ethene/propene/carbon monoxide polymers and ethene/butene/carbon monoxide (EBCO) polymers, predominately contain the β-rich crystalline phase. The crystalline density of this phase drops with increasing second olefin content, albeit at a faster pace for propene polymers. From the latter results, and from the behaviour of the melting point, crystallinity, and crystal thickness across composition, inclusion of methyl and ethyl side chains into the crystals as defects was inferred. Ethene/hexene/carbon monoxide (EHCO) polymers do seem to behave differently: they show lower crystallinity, the presence of a larger quantity of the denser α crystals and a relatively high and constant crystalline density for the β phase throughout composition; observations that unambiguously support the exclusion argument for the butyl branches. The above behaviour is surprising since for instance in polyethylene copolymers it is considered that only methyl branches can enter the crystal lattice. The relative presence of α crystals was found to decrease with increasing the concentration of branches and in the order EHCO>EBCO>EPCO. 相似文献
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Thermodiffusion has an important role in displacements of hydrocarbon reservoir. The ratio of the evaporation energy to the activation energy of viscous flow in pure limits, τpure,k, is of a great importance in estimating the thermodiffusion coefficient for non‐associating fluid mixtures. Several methods may be used to estimate τpure,k which causes different values for thermodiffusion coefficients. A fixed value for τpure,k was considered to predict the thermodiffusion coefficient. In this paper, Abbasi et al.'s [J. Non‐Equilib. Thermodyn. 2010;35:1–14] model and Shukla and Firoozabadi's model have been applied to predict thermodiffusion coefficients for linear chain hydrocarbon binary mixtures. The results show a very good performance of the simple approach in respect to the previous models in estimating thermodiffusion coefficients. © 2011 Canadian Society for Chemical Engineering 相似文献
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空分精馏系统最佳氩馏分位置的确定 总被引:3,自引:0,他引:3
指出在同时生产高纯度的氢、氮及粗氩产品,并带粗氩塔的空气分离双级精馏系统中,双级精馏塔的上塔存在最佳抽氩馏分位置,并介绍其确定方法。 相似文献
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目前,全日制专业学位研究生在校生已具有相当规模,他们的思想状况究竟有哪些特质,给我们的思政工作带来了哪些新挑战,突破点在哪里?这些都是我们亟待解决的问题。本文旨在结合作者的工作体会,对以上问题进行探究。 相似文献
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研究了铝件在阳极氧化的预处理、氧化、染色环节产生"白斑"、"花斑"的原因,认为机械加工过程中乳化油腐蚀、阳极氧化过程中零件夹持状态不合理、零件染色时形成的封闭气囊都会产生"白斑"或"花斑",但形态不同;根据不同环节产生"白斑"的原因,提出了预防和消除"白斑"的措施。 相似文献
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The surface strain of a solid is related to the surface free energy (interfacial superficial work) by the Shuttleworth equation. Its generalization for the case of a finite surface strain has been derived only recently by one of the present authors (B.M.G). Now consequences are derived for the case of an elastic spherical electrode. At first, it is shown that this generalized form is in accordance with the Laplace formula connecting the capillary pressure with the surface stress. Further, the generalized Shuttleworth equation leads to an additional term in the Gibbs adsorption equation, which is of first order in the elastic strain. Whereas this first order term may be negligible in the adsorption equation itself even for non-infinitesimal strain, it leads to a significant modification when considering second order derivatives of surface charge and surface stress which are directly accessible in experiments. A reformulation is presented for changing variables and the applicability to small particles is discussed. 相似文献
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马步真 《硫磷设计与粉体工程》2002,(2):9-12
硝酸磷肥的工艺流程有多种。介绍了国内外硝酸磷肥的发展简况 ,我国 90 0kt/a间接冷冻法和 16 5kt/a混酸法两套硝酸磷肥装置的生产方法和特点 ,分析了上述混酸工艺改为磷酸—硝酸混酸工艺后 ,可随时调整产品中有效养分的比例 ,有利于参与国内外市场竞争 ,并对新建硝酸磷肥装置就建厂条件、生产规模、工艺路线和原料供应等提出建议。 相似文献
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以美国环保局的污染物排放标准形成文件为依据,详细介绍了美国炼焦行业水污染物排放标准,包括BPT、BAT、NSPS、PSNS/PSES、BCT标准。研究了标准的形成过程,分析了标准中各指标的意义。通过标准的制定可以看出美国在污染控制方面的时间表,这对于我国煤化工行业的标准制定和应用具有很好的借鉴作用。 相似文献
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L. H. Camacho 《Journal of the American Oil Chemists' Society》1981,58(3):125-127
The primary center of genetic dispersion of the soybean probably is in northeastern China. The soybean plant traveled from
its area of origin to Korea and Japan in ancient times and to Europe and America more recently. Although soybeans were confined
to the Far East for many centuries, the western world now produces more than 80% of the total, and the United States and Brazil
are the main producers. The increased expansion of soybeans in Latin America is largely a result of the advances of genetic
and agronomic technology, which have permitted the development of adapted cultivars and improved management systems for the
subtropical and tropical areas of this region. The USDA soybean germplasm collection—particularly the gene bank maintained
in Mississippi—has been the most important genetic resource for the developing commercial cultivars in Brazil, Columbia, Ecuador
and Peru. Germplasm from other countries, e.g., Japan, Korea, Taiwan, Indonesia, India, the Philippines and some African countries,
also has contributed to the enrichment of the soybean gene pools in Latin America, mainly through the International Soybean
Program (INTSOY). The International Soybean Variety Evaluation Experiment (ISVEX) of INTSOY has been planted in more than
1,200 locations and in more than 107 countries since 1973. In Latin America in 1978, this experiment was planted in 29 locations
of 11 countries. The experiment was designed to (a) test the adaptation of cultivars, (b) compare local and introduced cultivars,
(c) provide new germplasm for local breeding programs, (d) identify potential areas for soybean production, and (e) evaluate
cultivar performance in different environments. 相似文献