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91.
本文介绍核孔膜生产线,重点描述了膜微孔制备工艺的实验研究。对于PC和PES膜,已得到32种工况下的扩孔公式,其形式为D=A+Bt,其中D——孔径,t——扩孔时间,A,B为特定工艺参数下的常数值.通过实验。得到了膜孔密度N与300~#核反应堆功率P、热柱辐照位置L的经验公式,即N=6.97×10~5×10~3×101~(1.18L).在本生产线上可生产最大幅面为3 140mm×240mm,孔径为0.04~10 μm的多系列多规格的核孔膜产品。 相似文献
92.
本文综述了非均匀介质中场与波理论近年来的研究进展及其应用成果,着重介绍了非均匀介质中的电磁场正演分析和反演计算中的各种高效数值方法,以及它们在电法测井数值模拟和成象研究中的成功应用。 相似文献
93.
The production of porous polymeric particles is attractive for a large number of applications and can be achieved by various techniques. Although numerous production schemes exist for glassy polymers, difficulties arise for soft, rubbery materials that need a chemical crosslinking step, such as elastomers. This is particularly true for poly(dimethylsiloxane) (PDMS), which shows the lowest glass‐transition temperature among the polymers. Recent studies suggest in situ hydrogen bubble formation or vacuum drying of water droplets dispersed in the polymer matrix in order to generate porous PDMS structures. In this work we report early results based on the chemical crosslinking of water in PDMS emulsion droplets in a mechanically stirred thermostated water vessel. This approach is shown to lead to high porosity PDMS beads (ca. 10?3 m particle diameter) with an open structure whose properties (diameter and porosity) are strongly influenced by the starting composition (solvent, surfactant, and polymer types and ratios), as well as the operating parameters (agitation and temperature). The possible uses of these derived beads are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 967–971, 2002 相似文献
94.
P. Bocchetta C. Sunseri A. Bottino G. Capannelli G. Chiavarotti S. Piazza F. Di Quarto 《Journal of Applied Electrochemistry》2002,32(9):977-985
Alumina membranes were fabricated by anodizing aluminium metal in 0.15 M oxalic acid. The growth kinetics of the porous layer were investigated in the temperature range –1 to 16 °C using linear potential scans up to 70 V. The faradaic efficiencies of metal oxidation and of porous layer formation, determined by applying Faraday's law, were found to be independent of both temperature and electrical charge. SEM analysis of the metal-side and solution-side surfaces revealed different morphologies. After dissolution of the barrier layer in phosphoric acid, the metal-side surface showed circular pores whose size of about 90 nm was found to be uniform and independent of temperature. The pore population was also practically independent of temperature and a value of about 4 × 1013 pores m–2 was determined. On the solution-side surface the presence of a deposit partially occluding the mouths of pores was observed. This coating could be removed by chemical etching in NaOH or thermal treatment at 870 °C, where decomposition of oxalate occurs. This supports the hypothesis that the deposit consists of an aluminium salt containing oxalate anions precipitated from the solution. The results show that it is possible to control the morphological characteristics of the anodic alumina membranes by careful choice of experimental conditions. 相似文献
95.
A. Stein 《Advanced materials (Deerfield Beach, Fla.)》2003,15(10):763-775
This report highlights developments in the fields of microporous and mesoporous materials that were published mostly during the year 2002. Selected examples are provided to illustrate new zeolite structures, porous coordination materials, mesoporous solids with new compositions, controlled morphologies, and increased hydrothermal and thermal stabilities, as well as porous solids with tunable pore openings or other structural features that can be dynamically modified. A number of applications are discussed, including stabilization of reactive guests, separations, electronic materials, and sensors. 相似文献
96.
文中提出并实现了一种基于点对点通信、按功能组织的分层分布双总线通信方案。通过引入镜像节点、总线负荷均衡等技术,使该方案可灵活高效地实现分布自动化功能和信息局部整合,并消除了分层通信对系统通信可靠性和速度的影响,同时,定量分析了该通信方案的可靠性。此通信方案已在部分变电站得到实际应用,并取得了理想效果。 相似文献
97.
本文导出了线性波浪作用于上部可渗透的直立刚性圆柱体上的水动力的解析解。在线性有势流的假定下,用特征函数展开方法求出了内部和外部流场的解。给出了不同波浪要素及结构尺寸参数下的数值结果。由结果可知,提高可渗透性可以有效消减波幅。 相似文献
98.
99.
Ashraf Bastawros Abhijit Chandra Yongjin Guo Bo Yan 《Journal of Electronic Materials》2002,31(10):1022-1031
The role of a porous pad in controlling material-removal rate (MRR) during the chemical-mechanical planarization (CMP) process
has been studied numerically. The numerical results are used to develop a phenomenological model that correlates the forces
on each individual abrasive particle to the applied nominal pressure. The model provides a physical explanation for the experimentally
observed domains of pressure-dependent MRR, where the pad deformation controls the load sharing between active-abrasive particles
and direct pad-wafer contact. The predicted correlations between MRR and slurry characteristics, i.e., particle size and concentration,
are in agreement with experimentally measured trends reported by Ouma1 and Izumitani.2 相似文献
100.
VTI介质中弹性参数地震反演方法 总被引:2,自引:2,他引:0
根据地震波在具有垂直对称轴的横向各向同性(VTI)介质中的运动学特征,应用传播时间反演方法,进行了水平层状VTI介质的地层弹性参数反演方法研究。在VTI介质中,P-P波的传播时间曲线不再是双曲线,尤其在长排列情况下,已不能用二项泰勒展式精确地反演P-P波的传播时间,用三项泰勒展式则可以达到更高精度;P-SV波的传播时间也可用三项泰勒展式表达,在中等及短排列长度时可达到一定精神。对P-P波、P-SV波的传播时间进行三项泰勒展开时,它们的系数中包含了地震波的各向异性信息及垂直速度信息,中以为地震波的弹性参数反演提供提供基础,模试验分析及江苏油田某地区的二维多波资料实际反演结果表明,在最大炮间距为1.5倍地层埋深时,可以很精确地得到三项泰勒展式的系数,应用这些系数能精确反演地层弹性参数,包括P波、S波的垂直速度和各向异性参数。图4表1参5(杜丽英摘) 相似文献