Melting and crystallization behaviour of elastoplastic semicrystalline copolymers: poly(ether ester)

The melting and crystallization behaviour of an elastoplastic semi-crystalline poly(etherester) has been studied by differential scanning calorimetry. The shape of the melting endotherm is strongly dependent on heating rate and annealing time and results from the sum of simultaneous melting and crystallization phenomena. Samples prepared by different techniques, i.e. by solvent evaporation or by melt extrusion, behave very differently owing to specific crystal morphologies. By applying the Hoffman-Weeks plot, the equilibrium melting temperature has been extrapolated. The Avrami treatment allows the calculation of the index n and of the rate constant K from the isothermal kinetic data.     

Design Methodology of the Structure of Postal Express Mail Networks of Aviation Channels in China

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Studies on chitin 3—effect of coagulants and annealing on the preparation and the properties of chitin membrane

Chitin membrane was prepared by casting a N,N-dimethyl acetamide, N-methyl 2-pyrrolidone and lithium chloride (DMA-NMP-LiCl)solution of chitin and coagulating with several media. The effect of the coagulants on membrane formation was studied. 2-Propanol was found to be more favourable than methanol, ethanol, acetone and mixtures of 2-propanol and water. The membrane obtained in 2-propanol was subjected to annealing. Annealing made the membrane dense and strong. The tensile strength of the membrane annealed at 145°C for 2hr was about twice that of an unannealed membrane. The solute permeability of the annealed membranes was lower than that of the original one. These phenomena could be clearly interpreted in terms of crystallinity.     

Optimal Operation of Reservoir Systems using Simulated Annealing

A stochastic search technique, simulated annealing (SA), is used to optimize the operation of multiple reservoirs. Seminal application of annealing technique in general to multi-period, multiple-reservoir systems, along with problem representation and selection of different parameter values used in the annealing algorithm for specific cases is discussed. The search technique is improved with the help of heuristic rules, problem-specific information and concepts from the field of evolutionary algorithms. The technique is tested for application to a benchmark problem of four-reservoir system previously solved using a linear programming formulation and its ability to replicate the global optimum solution is examined. The technique is also applied to a system of four hydropower generating reservoirs in Manitoba, Canada, to derive optimal operating rules. A limited version of this problem is solved using a mixed integer nonlinear programming and results are compared with those obtained using SA. A better objective function value is obtained using simulated annealing than the value from a mixed integer non-linear programming model developed for the same problem. Results obtained from these applications suggest that simulated annealing can be used for obtaining near-optimal solutions for multi-period reservoir operation problems that are computationally intractable.     

洁净钢生产技术初探

主要论述钢的洁净度与其性能之间的关系,以及近年来国内外主要钢厂生产洁净钢控制钢中杂质元素[C、S、P、N、H、O]技术的进展,为鞍钢纯净钢的生产提供有益的借鉴.     

IFP连续重整新一代催化剂再生技术的改进

介绍了我国引进的采用法国石油研究院 (IFP)三代催化剂连续再生技术的重整装置 ,分析了第二、第三代技术在原有基础上的改进 ,从再生气循环回路、再生操作参数和再生器内部结构三个方面重点介绍了第三代催化剂连续再生技术的特点和优势 :使催化剂的烧焦气循环回路与氧氯化用气、焙烧气循环回路彼此分开 ,烧焦、氧氯化、焙烧的操作参数可分别得到优化 ,使氧氯化及焙烧在高氧条件下进行 ,有利于催化剂金属的再分散 ,保持催化剂的活性。     

用离子束混合及快速热处理方法形成钽的硅化物

本文描述用离子束透过钽金属膜进行混合和快速热处理方法来形成钽的硅化物.用溅射方法在P型硅衬底上淀积一层金属钽,然后用砷离子束透过钽金属模进行混合,采用快速热处理后形成了平整的硅化钽薄层.使用厚度为500埃的钽金属膜,得到钽的硅化物薄层电阻为5.5Ω/□.研究了砷离子能量、剂量及钽膜厚度对钽的硅化物薄层电阻的影响.用透射电镜和台阶仪对所形成的硅化钽进行了分析和厚度测量.     

离子注入半导体的快速热退火与SOI技术

自1977年以来,为了摸索离子注入半导体的新退火方法,各国学者进行了大量的研究工作。这种努力是从激光退火的研究开始的。激光与半导体材料相互作用的研究,已派生出若干很有生命力的应用项目,其中,快速热退火、SOI(Semiconductor on Insulator)技术等已显示了重要的应用前景,并正在走向实用化。     

攀钢转炉炼钢用碳化硅提温的试验研究

低品位碳化硅是转炉炼钢的有效提高温剂。工业性试验结果表明，碳化硅加入８．０ｋｇ／ｔ钢水提温４０．３－７０．３℃（平均４８．４℃）；渣中ＴＦｅ降低１．３％；加提温剂有利于转炉内造渣脱硫和碱少炉渣对耐火砖的侵蚀。文中还给出了攀钢转炉半钢冶炼铸用钢不水时加与不加碳化硅的ｔλ，［Ｃ］λ区域。     

3961连续重整催化剂性能考察

新一代高活性，高水热稳定性3961（PS－Ⅳ）型连续重整催化剂于1996年在上海石化芳烃厂400kt/a连续重整装置上首次进行工业应用试验。开工5a，催化剂跟踪分析结果表明，该剂保持了良好的物化性质和反应性能，表现为良好的比表面积稳定性和持氯能力，经过200个以上再生周期的催化剂未发现有明显的相变和金属分散度的变化。