深亚微米MOSFET衬底电流的模拟与分析

利用器件模拟手段对深亚微米ＭＯＳＦＥＴ的衬底电流进行了研究和分析，给出了有效的道长度，栅氧厚度，源漏结深，衬底掺杂浓度以及电源电压对深亚微米ＭＯＳＦＥＴ衬底电流的影响，发现电源电压对深亚微米ＭＯＳＦＥＴ的衬底电流有着强烈的影响，热载流子效应随电源电压的降低而迅速减小，当电源电压降低到一定程度时，热载流子效应不再成为影响深亚微米ＭＯＳ电路可靠性的主要问题。     

利用地理信息系统ARC/INFO计算地物面积的方法

详细介绍利用地理信息系统工具ARC/lNFO来计算地物分布专题图中各种不同地物面积的方法，并给出海南省大边河库区地物面积的计算实例。     

SnO2超微粒子薄膜的气敏特性研究

作者用自行设计的直流气体放电活化反应蒸发装置制备出平均粒径约为40nm的SnO_2超微粒子薄膜.研究了不同氧分压下所得SnO_2超微粒膜的形貌、结构和组成等特性,以及不同样品对各种易燃气体的气敏特性,得出了灵敏度随氧分压及灵敏度随工作温度的变化曲线.     

采用8031作主控器的时域FIR数字滤波器

长期以来，ＦＩＲ数字滤波器大多是在频域上实现。因为，在时域上实现ＦＩＲ数字滤波所遇到的首要问题，是输入信号序列与冲激响应序列的卷积运算速度难以提高。然而，随着超大规模集成电路的飞速发展，硬件集成度与运算速度获得极大的改观，在时域上实现ＦＩＲ数字滤波已成为可能。ＩＭＳＡ１００是高速、高精度３２级数字信号处理器，是完成卷积运算的理想器件。本文论证了用ＩＭＳＡ１００实现时域ＦＩＲ数字滤波器的可行性和硬件设计中的一些问题，并给出了应用举例。在设计中选用８０３１单片机做主控器，大大提高了性能价格比，使这一设计具有很高的实用价值。     

基于工作站和EUCLID－IS的计算机组装结构CAD系统研究

随着集成电路技术的发展及计算机性能的不断提高，计算机组装结构设计在计算机，总体设计中的地位越来越重要，它直接影响到计算机性能的提高。本文针对一个基于工作站和ＥＵＣＬＩＤ－ＩＳ软件的电子计算机组结构ＣＡＤ系统，从软、硬件平台，系统功能及实现等方面进行了讨论，旨在为电子计算机组装结构设计提供一种强有力的、方便的设计工具，有利于增强国产计算机的市场竞争能力。     

VME总线评述

ＶＭＥ总线是应用最广泛的国际总线标准之一。本文介绍了ＶＭＥ总线的结构特别，包括信号名的定义及功能等，特别阐明了ＶＭＥ总线的并行性、实时性和高可靠性，突出了ＶＭＥ总线的发展前景。     

基于图形约束的工程图纸扫描图象表面粗糙度的自动识别

本文通过分析现有工程图纸扫描图象的识别与理解系统，提出了表面粗造度的自动识别算法，从而弥补了以往系统的不足，基于图形约束的表面粗造度整体识别算法符合技术人员的读图规律，处理速度快，可靠性高，该算法已在微机上调试成功。     

Measurements and correlation of effect of cosolvents on the solubilities of complex molecules in supercritical carbon dioxide

A new transparent microscale circulation-type high pressure equilibrium cell with on-line sampling was devised. With this apparatus, experimental solubility of molecularly complex species such as steroids (cholesterol, stigmasterol and ergosterol) and fatty acids (palmitic acid and stearic acid) in supercritical carbon dioxide(sc-C0₂) were measured. Also, to find an appropriate substance for enhancing both the polarity and the solubility power of the SC-CO₂ solvent, we arbitrarily selected three polar substances such as acetone, methanol and water and the effect of these cosolvents on the solubility of solutes in SC-CO₂ are examined. The supercritical phase equilibrium data of solute-cosolvent-sc-CO₂ systems were quantitatively correlated using a new equation of state based on the lattice fluid theory incorporated with the concept of multibody interaction. We found that the addition of tracer amount of acetone or methanol to SC-CO₂ enhances the solubility of all solutes about thirty to sixty times when compared with the case of pure sc-CO₂ However, for the case of cosolvent water, no further enhancement of the solubility of solutes was realized. Also, the versatile fittability of the equation of state proposed in this work was demonstrated with the newly measured ternary supercritical equilibrium data.     

Kinetic analysis of the coding properties of O6-methylguanine in DNA: the crucial role of the conformation of the phosphodiester bond

Production by N-nitroso compounds of O6-alkylguanine (O6-alkylG) in DNA directs the misincorporation of thymine during DNA replication, leading to G:C to A:T transition mutations, despite the fact that DNA containing O6-alkylG:T base pairs is less stable than that containing O6-alkylG:C pairs. We have examined the kinetics of incorporation by Klenow fragment (KF) of Escherichia coli DNA polymerase I of thymine (T) and of cytosine (C) opposite O6-MeG in the template DNA strand. Both T and C were incorporated opposite O6-MeG much slower than nucleotides forming regular A:T or G:C base pairs. Using various concentrations of dTTP, dCTP, or their phosphorothioate (Sp)-dNTP alpha S analogues, or a mixture of dTTP and dCTP, the progress of incorporation of a single nucleotide in a single catalytic cycle of a preformed KF-DNA complex was measured (pre-steady-state kinetics). The results were consistent with the kinetic scheme (Kuchta, R. D., Benkovic, P., & Benkovic, S. J. (1988) Biochemistry 27, 6716-6725): (1) binding of dNTP to polymerase-DNA; (2) conformational change in polymerase; (3) formation of phosphodiester between the dNTP and the 3'-OH of the primer; (4) conformational change of polymerase; (5) release of pyrophosphate. The results were analyzed mathematically to identify the steps at which the rate constants differ significantly between the incorporation of T and C. The only significant difference was the 5-fold difference in the rates of formation of the phosphodiester bond (for dTTP, kforward = 3.9 s-1 and kback = 1.9 s-1; for dCTP, kforward = 0.7 s-1 and kback = 0.9 s-1). These pre-steady-state progress curves were biphasic with a rapid initial burst followed by an apparently steady-state rise. Deconvolution of these curves gave direct evidence for the importance of the conformational change after polymerization by showing that the curves represented the sum of the rapid accumulation of the product of step 3 followed by the slow conversion of that to the product of step 5 (because of the rapidity of the release of pyrophosphate there was no significant accumulation of the product of step 4). The equilibrium constants for each step suggest that the greatest change in the Gibbs free energy occurs at the conformational change after polymerization and that while the formation of the phosphodiester bond to T is slightly exothermic, that to C is slightly endothermic.(ABSTRACT TRUNCATED AT 400 WORDS)     

采用区内C／I平衡的多区峰窝CDMA系统下行链路的性能

本文对采用区内Ｃ／Ｉ平衡的多区蜂窝ＣＤＭＡ系统下行链路的性能进行分析，给出两种区内Ｃ／Ｉ平衡算法并比较它们的性能，考虑呈对数正态分布的阴影和Ｒ＾－４规律的路径损失的综合影响，采用与传统不同的小区平均中断概率来评价系统的性能。