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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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To develop a simple and efficient way to recycle used cigarette filters, we report on a one-step method for preparing superhydrophobic and superoleophilic cigarette filters for oil–water separation. The robust coating layer on the surface of the cellulose acetate fiber, along with the inherent rough texture of the cigarette filter, could lead to its surface that displayed superhydrophobicity and superoleophilicity. Water droplets can retain in spherical shapes on the modified cigarette filters, while oils were immediately absorbed by the cigarette filters with high absorption capacity. As a result, free oil–water mixtures were separated with efficiency of above 98.0% by the driving force of gravity, and water-in-oil emulsion was also separated with a promising flux of about 2500 L m?2 h?1. The purity of oil for the tested emulsion was above 99.96%, indicating extremely high separation efficiency. This method for the fabrication of the superhydrophobic and superoleophilic cigarette filters would be a good candidate for recycling the solid wastes and developing an economic oil–water separation material to meet emerging needs in practical applications. 相似文献
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Douglas W. VanOsdell Benjamin Y. H. Liu Kenneth L. Rubow David Y. H. Pui 《Aerosol science and technology》2013,47(4):911-925
The fractional penetration of submicrometer particles through five high-efficiency glass fiber filters, one composite fiber filter, and two membrane filters was measured for particles of 0.004–0.42-μm diameter at filter face velocities ranging from 0.5 to 20 cm/s. The glass fiber filters all had approximately the same thickness and weight per unit area, and were rated 93% to 99.999% efficient using the conventional 0.3-μm dioctyl phthalate (DOP) test. The challenge aerosols were electrically classified monodisperse DOP in the diameter range of 0.032–0.42 μm, and polydisperse silver condensation aerosols having diameters of ~ 0.004–0.01 μm. Aerosol penetration through these media was found to be generally consistent with current theory for collection by diffusion and interception over the particle size and velocity range studied. Using a filter figure of merit calculated for penetration by 0.1- and 0.3-μm particles to facilitate comparison, all of the filters except one tetrafluoroethylene membrane filter (which was slightly better) had about the same performance. 相似文献
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超高效过滤器设计参数的确定 总被引:1,自引:0,他引:1
从过滤精度与比速的角度出发,讨论了过滤阻力、使用寿命等影响超高效过滤器技术经济综合性能的几个因素,为亚微米级超高效除油、除尘过滤器设计参数的选择提供了依据。 相似文献
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Sung Ho Hwang Jaehoon Roh Chanjung Park Jongcheol Kim Byong Hyoek Lee 《Aerosol science and technology》2018,52(9):1005-1011
The purpose of this study was to improve the efficiency of filters used in asbestos control systems, such as those used at asbestos removal sites. We evaluated the melt-blown (MB) filter media for their asbestos removal efficiencies. The filter grades were based on the ISO and European standards (EN 1822) of E12 (≥99.5% collection efficiency) and H13 (≥99.95% collection efficiency) with a size of <0.2?μm asbestos diameter. Based on test chamber experiments, the asbestos removal efficiency of the grade H13?MB filter (99.974%) was higher than that of the E12 grade MB filter (97.120%). In addition, the lowest level of pressure drop was observed in the case with a 3.8?mm pitch interval. The concentrations of airborne asbestos based on phase contrast microscopy in the sites with asbestos concentrations presenting high risks before turning on the asbestos control system was 0.038 fiber cm?3 at demolition site A and 0.027 fiber cm?3 at demolition site B. Chrysotile asbestos was detected at both demolition sites A and B before turning on the system, but were not detected after using the system. Therefore, MB filters present an efficient alternative to current commercial filters and should be considered for use in asbestos removal applications.© 2018 American Association for Aerosol Research 相似文献
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《分离科学与技术》2012,47(8):1955-1973
Abstract Coalescing filters are widely used throughout industry for removal of liquid aerosols from gases or the separation of liquid droplets from emulsions. Typical filters are constructed of non-woven fibers. Fibrous filters are capable of efficient removal of micron and submicron sized droplets and particles. The filtration process is highly complex due to variability in fiber sizes, particle sizes, mixtures of particles and droplets, mixture of types of droplets (oil, water, etc.), and effects of viscosity, surface tension, and chemical reactions between components or with the filter fibers. Prediction of filter performance under such complex conditions is difficult. Performance of a filter depends on many factors like particle and fiber sizes, flow rate, surface properties of the fibers etc. One of those parameters is the saturation of the filter medium. Saturation is a measure of the amount of liquid present in the void space. Prior models assume that the saturation is uniform along the depth of the medium. In real media, the liquid holdup at steady state need not be uniform with position. Local velocity increases when the saturation is high. In this paper, a steady state model for a coalescing filter is used to evaluate the effects of saturation on void fraction and its subsequent effect on filter performance. Single fiber mechanisms of direct interception and diffusion deposition are used to model droplet capture efficiencies and drag forces. These mechanisms are applied to volume averaged continuum equations in which the saturation is varied linearly with position in the filter. The results show the minimum pressure drop and largest quality factor occurs with a uniform saturation profile and that variation in average saturation has a greater effect on filter performance than does the slope of the linear saturation profile. The model predicts that uniform saturation profile performs better than the other profiles. 相似文献
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Although theoretical models of the filtration efficiency of fibrous filters are typically based on a single type of fiber in an ordered array, many actual fibrous filters comprises fibers that are inherently randomly distributed. It is desirable to be able to estimate the filtration efficiency of such non-uniform fibrous filters from their composition arrangement and the filtration property of individual fibers. Toward that end, we approximate the filter system as a series of cells comprising individual fibers with random distribution, deviating from the homogeneity assumption in the classical models. With better characterization of the filter structure based on the Voronoi diagram, we theoretically revisit filtration efficiency by the top-down (TD) approach and the bottom-up approach. The proposed models are compared with the existing experimental and numerical results under different fiber volume fractions, indicating the high accuracy of the TD model for the filtration of submicron aerosol particles. The influence of the degree of randomness of fiber distribution on filtration efficiency is also quantified.Copyright 2015 American Association for Aerosol Research 相似文献