N.m.r. line shape-relaxation correlation analysis of bitumen and oil sands

The first results of the analysis of bitumen and oil sands using the recently developed n.m.r. spingrouping technique are presented. The n.m.r. relaxation experiments were carried out on bitumen, and on natural and dried oil sands samples. The results indicate that the spin-grouping can resolve and quantify several components of the samples studied. The bitumen and bitumen fraction of the oil sands are resolved according to their spin-spin relaxation times into three major groups: solid-like (rigid), solid-like (mobile) and semi-liquid. The water in the oil sands exists in two different environments. Tentatively one environment is assigned to be the bridges between the sand grains, while the other is assigned to be the clay surface. One can conclude that with spin grouping of complex mixtures the decomposition (in which components are resolved according to their dynamic state) is possible. The accuracy of such resolution is of the order of a few per cent.     

具有部分n~+浮空埋层的高压SJ-LDMOS器件新结构

为了抑制衬底辅助耗尽(SAD)效应并提高超结器件击穿电压,提出一种具有部分n+浮空层SJ-LDMOS新结构。n+浮空等位埋层能够调制器件横向电场,使得partial n+-floating SJ-LDMOS比传统SJ-LDMOS具有更加均匀的电场分布。通过三维仿真软件对新器件结构分析,与传统SJ-LDMOS进行比较。仿真结果表明,具有部分n+浮空层SJ-LDMOS结构的器件能将器件的击穿电压从138V提高到302V,且比导通电阻也从33.6mΩ·cm2降低到11.6mΩ·cm2,获得一个较为理想的低导通电阻高压功率器件。     

从H∞到Bloch空间的积分算子特性研究

研究单位圆盘上从有界解析函数空间到Bloch空间的积分算子Cφn,u的有界性和紧性。讨论算子IgCφ和JgC,当n=1时,u（z）=φ（z）g（z）,积分算子Cφn,u为Cφn,u;当n=0时,u（z）=g≮z）,积分算子Cφn,u为JgCφ在此基础上,通过推导得到从有界解析函数空间到Bloch空间的积分算子的有界性和紧性的充要条件。     

n阶方阵乘积的行列式定理的两种简单证明方法

n阶方阵乘积的行列式定理 ,在工科《线性代数》教材中提及很少 ,然而这一定理有着广泛的应用。通常在此定理的证明中多用拉普拉斯定理 ,本文应用初等变换和向量空间来证明 ,使证明既简便又有所深化     

SiCp/Cu复合材料热膨胀性能研究

以电子封装基片为应用背景,采用挤压铸造方法制备了体积分数为55％,不同颗粒粒径增强的SiCp／Cu复合材料,并分析测试了颗粒粒径和热处理状态对材料热膨胀性能的影响规律．显微组织观察表明,复合材料颗粒分布均匀,材料组织致密;热膨胀性能测试表明,随着温度升高,复合材料的热膨胀系数呈非线性增加;SiC体积分数相同时,减小SiC颗粒尺寸有利于降低复合材料的热膨胀系数;退火处理可以减小基体中的热残余应力,有助于降低复合材料的热膨胀系数．     

Structures and properties of [CoPt/Ag]_n multilayer films

In recent years there has been considerable interest in atomically ordered L10-CoPtfilms as potential materials for ultrahigh density magnetic recording (UDMR) media[1].The L10 phase CoPt alloy has high anisotropy constant of 107—108 erg/cm3, which is ofcrucial importance for UDMR media with a small grain size below 10 nm, because highmagnetocrystalline anisotropy is needed to create a barrier to thermally activatedswitching of the magnetization[2, . The as-deposited CoPt film with equi…     

用变n次抛物线叠加敷设缓和曲线

按汽车转向时的实际特性分析了公路缓和曲线应满足的理论关系，并采用了变ｎ次抛物线在切线上和圆弧上分别叠加，从而使所敷设的缓和曲线更简化，更附合实际。     

Analysis of the Thermal Explosion in Systems Porous Reagent–Active Gas–Solid Product

The specific features of dynamics of the thermal explosion in systems porous reagent–active gas–solid product under conditions where the heattransfer and masstransfer regions are separated from the ambient medium are considered. In addition to the competition of heat release and heat removal, the process of initiation of exothermal chemical interaction in these systems under normal pressures depends significantly on conditions of filtration transport of the gaseous reagent. The induction and postinduction periods of the thermal explosion are studied. The theoretical analysis of thermalexplosion issues is supplemented by an experimental study of the process for the porous titanium–nitrogen–titanium nitride system.     

人血浆蛋白C的纯化与鉴定

目的　建立人血浆蛋白C的纯化与鉴定方法。方法　利用DEAE SephadexA 5 0代替氯化钡 ,对血浆进行预处理 ,再经DEAE SepharoseFF离子交换和肝素 SepharoseCL 6B亲和层析进行分离纯化 ,用活化的部分凝血活酶时间 (APTT)测定组分活性 ,非还原型SDS PAGE测定其相对分子质量 ,Westernblot鉴定其特异性。结果获得相对分子质量为 6 2 0 0 0的蛋白条带 ,此条带可与人蛋白C单克隆抗体发生特异性反应。结论　已成功地从血浆中分离到蛋白C ,为其规模化生产奠定了基础。     

Molecular transport of n‐alkanes into PU/PBMA interpenetrating polymer network systems

The methylene diisocyanate (MDI) and toluene diisocyanate (TDI) based polyurethane/polybutyl methacrylate (PU/PBMA‐50/50) interpenetrating polymer network (IPN) membranes have been prepared. The molecular migration of n‐alkane penetrants such as hexane, heptane, octane, nonane, and decane through PU/PBMA (50/50) membranes has been studied at 25, 40, and 60°C using a weight gain method. From the sorption results, diffusion (D) and permeation (P) coefficients of n‐alkane penetrants have been calculated. Molecular migration depends on membrane‐solvent interactions, size of the penetrants, temperature, and availability of free volume within the membrane matrix. Attempts have been made to estimate the parameters of an empirical equation and these data suggest that molecular transport follows Fickian mode. From a study of temperature dependence of transport parameters, activation energy for diffusion (E_D) and permeation (E_P) have been estimated from the Arrhenius relation. Furthermore, sorption results have been interpreted in terms of enthalpy (ΔH) and entropy (ΔS) of sorption. The liquid concentration profiles have been computed using Fick's equation with appropriate initial and boundary conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 739–746, 2003