共查询到20条相似文献,搜索用时 93 毫秒
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研究不同拉伸条件(热拉温度、拉伸比、拉伸速率、预热温度及时间,热定型温度及时间)对薄膜微孔的影响,并确定最优拉伸工艺为在预热温度100℃,定温时间5min,拉伸温度为110℃以及热定型温度120℃,定温时间5min下,热拉程度60%:先萃取后拉伸工艺,拉伸速率为30mm/min,先拉伸后萃取工艺,拉伸速率为10mm/min时,拉伸出的微孔数量较多且分布均匀。因此,为了得到孔径比较均匀且量较多的微孔膜,拉伸程度不宜过大,拉伸速率较小。 相似文献
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从自加速分解温度(SADT)评价含能物质的热危险性出发,分析了联合国危险物运输专家委员会推荐的几利-方法对含能材料热危险性评价的局限性,简述了与热分析法相关的测定含能材料自加速分解温度的方法,主要有加速量热仪法、TG—DTA、DSC、微量热法、动力学模拟法、绝热自点火实验法等。同时对各种方法的优缺点分别进行了分析,讨论了热分析法评价含能材料热危险性的发展趋势。 相似文献
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采用三种不同的动力学分析方法,即Freeman方法、Flynn-Wall-Ozawa以及Kissinger方法对不同类型聚乙烯的热分解动力学进行了探讨。结果表明,Flynn-Wall-Ozawa法I、Friedman法的测试结果与三者聚乙烯的结构特征较吻合,不同聚乙烯降解活化能的大小顺序为HDPE>LLDPE>LDPE。 相似文献
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本文介绍了美国五种用于测定PUF及其制品阻燃性能的新方法,它们是:美国FMUSS-302法,美国加州117A法,117D法,TB133法及TB129法。文中汇集了这些方法的试验装置、试验条件及通过标准。这五个方法目前均未在我国应用,但可供借鉴。此外,本文对可用于测定材料多种阻燃参数的小型锥形量热计的原理及应用也做了简要的叙述。 相似文献
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于剑昆 《化学推进剂与高分子材料》2007,5(3):8-14
<正>2.7用承载的Pd作催化剂村田和久等人介绍了一种用Ti-MCM-22和Pd化合物的混合物作催化剂,使丙烯与O2在液相中反应来生产PO的工艺[28]。MCM-22用水热-煅烧法合成,然后用溶浸法使Ti化合物承载,在空气中 相似文献
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从化学法和生物法两个方面系统地总结了手性β-羟基酸的合成方法,并通过分析和比较各种方法的优缺点,对合成手性β-羟基酸的发展前景进行了展望. 相似文献
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Kerry Ward Rachael Scarth J. K. Daun C. T. Thorsteinson 《Journal of the American Oil Chemists' Society》1994,71(9):931-934
There are several methods available to measure chlorophyll in canola oil and seed, and these will not necessarily yield the
same results and should not be used in terchangeably. Total chlorophyll was determined for samples of canola seed and commercial
canola oil by recognized spectrophotometric methods and by high-performance liquid chromatography (HPLC). The HPLC method,
which summed all chlorophyll-related pigments detected, found approximately 1.4 times more total chlorophyll per sample than
did the spectrophotometric methods. The spectrophotometric methods are calibrated with only chlorophyll a and underestimate
other chlorophyll pigments, which have lower extinction, coefficients and different absorption maxima. The HPLC method detects
each pigment at its absorption maxima and applies the appropriate absorptivity factor. Care must be taken when comparing results
obtained by different methods. There appears to be a need for a standardized method of chlorophyll pigment measurement by
HPLC. 相似文献
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详细介绍了近年来国内外铝电解槽用耐火材料抗冰晶石侵蚀测试方法的现状,系统分析比较了各种测试方法的优缺点。从耐火材料检测实践出发,提出了根据耐火材料实际应用状况和材料种类来选择适当的检测方法。全部浸入法和半浸入法适用于电解槽侧壁耐火材料,坩埚法主要适用于散状耐火材料。 相似文献
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Coimbatore V. Gurumurthy 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1973,23(10):725-731
Methods for the determination of O/M ratios in uranium and uranium-plutonium oxide nuclear fuels are reported based on an extensive literature survey. The salient features, as well as the merits and drawbacks of each method are critically reviewed. The need for a fast direct method, by which the simpler indirect methods may be checked, is met by the carbon-reduction method. 相似文献
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Malte Bartels 《Powder Technology》2010,203(2):148-8484
We have recently presented a new methodology for screening different signal analysis methods in combination with signal pre-treatment methods with the goal to effectively identify those combinations that are highly selective towards a specific process change (Bartels et al., Ind. Chem. Eng. Res. 48 (2009) 3158-3166). The main outcome of the methodology is visually represented in an overall result matrix with coloured tiles illustrating a measure for the suitability of each combination of analysis method and signal pre-treatment. Suitable methods can be visually identified very quickly.For the early detection of agglomeration in fluidized beds we illustrate this methodology by four different cases: two cases from a pilot-scale bubbling bed, one from an industrial scale bubbling bed and one case from a lab-scale circulating bed. With the result matrix for each case several suitable methods are identified. The data are also evaluated to identify methods that are more generally applicable for a range of different cases. The suitability of a positively identified method is subsequently analyzed for its temporal response to both agglomeration and other effects. The influence of the different data pre-treatment methods is also addressed. 相似文献
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A more accurate method (comparing to the Euler, Runge–Kutta, and implicit Runge–Kutta methods) for the numerical solutions of ordinary differential equations (ODEs) is presented in this paper. The coefficients in the approximate solution for the ODE using the proposed method are divided into two groups: the fixed coefficients and the free coefficients. The fixed coefficients are determined by using the same way as in the traditional Taylor series method. The free coefficients are obtained optimally by minimizing the error of the approximate solution in each time interval. Examples are presented to compare the numerical solutions of the Rahmanzadeh, Cai, and White's method (RCW) to those of other popular ODEs methods. 相似文献
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化学法制备ZrO2超细粉体 总被引:1,自引:0,他引:1
摘介绍了化学法制备ZrO2超细粉体常用的几种方法:沉淀法、溶胶-凝胶法、水热法、沉淀-乳化法等;介绍了各种制备方法的工艺流程及其特点。 相似文献
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邻、间、对苯二甲酰氯的合成工艺 总被引:2,自引:0,他引:2
介绍了以邻苯二甲酸酐为原料,采用光气法、氯化亚砜法或氯代烃法等制备邻苯二甲酰氯的工艺和以间/对苯二甲酸为原料,采用光气法、氯化亚砜法、金属氧化物法、羧酸/酉自法等制备间/对苯二甲酰氯的工艺,对各合成方法的优缺点进行了评价。通过工艺对比可知,以邻苯二甲酸酐或间屑寸苯二甲酸为原料,采用光气法和氯化亚砜法制备邻苯二甲酰氯或间/对苯二甲酰氯的工艺应用广泛;以间/对二甲苯为原料,先生成间/对六氯二甲苯,再与对应的苯二甲酸或者酯反应制备间履寸二甲酰氯的方法最经济。 相似文献
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There are some computational models for fluids viscosity calculation. However, each of these models is reliable in confined density. In this comparative study two methods are evaluated for viscosity prediction in all range of density. We determine the effectiveness of each of the models and we demonstrate the strengths and weaknesses of them. Viscosity of the six refrigerants is calculated by some computational models based on ChapmanEnskog and RainwaterFriend theories. Then a feed forward artificial neural network (ANN) with multilayer perceptrons is used to viscosity prediction and finally two methods (computational models and artificial neural network) are comparing. It is concluded that there is no opinion by computational methods to calculate viscosity from low to high density. The results show that prediction accuracy of computational models in low and moderate densities is good as ANN method. However artificial neural network has very good accuracy in high densities while computational method is defeated when the density is more than 8. 相似文献