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71.
72.
黄林 《东南大学学报(自然科学版)》1998,28(4):44-48
将信号流图扩展到状态空间构成所谓向量流图,用公式可实现组合系统规范化;按工答过程绘制信号流图构成所谓过程流图,可对系统组件作深入的分析。 相似文献
73.
夏富杰 《北京理工大学学报》1998,18(4):406-410
对柔性机构动力学进行建模和计算机模拟。方法以组成机构的构件为单元,把构件的刚性运动和弹性变形统一用模态参数表示;以梁单元为代表分析了集中质量及分布质量情况下的梁的惯性特征;引入弹性的概念, 相似文献
74.
Four basic explicit analytical solutions of non-Fourier heat conduction equation simulating IC chip thermal condition are
derived. Some other analytical series solutions can also be derived with the above-mentioned basic solutions. Analytical solution
has its own irreplaceable important meaning in theory. In addition, as the standard solution to check the accuracy, convergence
and effectiveness of various numerical computational methods and their differencing schemes, grid generation ways and so on,
the analytical solution is very useful also for the newly rapidly developing computational heat transfer. 相似文献
75.
Cytosine deaminase gene ofEscherichia coli strain H-30 was cloned, and its initiation codon of ‘GTG’ was mutated to ‘ATG’ by PCR. Prokaryotic recombinant expression
vector pBV220-CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine
deaminase. 5-FC(5-FC, 5-fluorocytosine) could induce the lethal toxicity to cells containing active CD gene. DNA sequence
analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide
by comparing DNA sequence of the clone H-30-CD-11 with high enzyme activity with CD gene reported in Gene Bank. 相似文献
76.
《科学通报(英文版)》1998,43(5):363-363
During the long period of time when people have been seeking for an effective therapeutic method for PD, the gene therapy has shown greater and greater advantages over other methods. It can be performed mainly in two ways: ex vivo and in vivo. With the former, TH gene as well as some neurotrophic factor genes (such as GDNF, BNDF genes) can be invited to some cell lines or primary cells thus forming engineered cells and then implanting them into brain. While with the latter, viral vectors including HSV-1, Ad, AAV that can be utilized to construct recombinant viruses, or non-virus vectors can be used to delived DNA into brain directly. The present review summarizes the recent research advances in the gene therapy for PD, and it is reasonable for us to predict a notable progress in prevention and treatment for PD in the next decade. 相似文献
77.
基于无调节参数的Gordon-Kim势和一种检测离子运动的新技术,以KCaF3的分子动力学模拟结果为例,对钙钛矿ABX3的离子分子固体的结构相变作了探讨.包括对阱势、折叠结构、能垒、超离子态、稳定性骨架和离子分子集团BX6的“尺寸”和“形状”.以期对离子分子固体的结构相变有一个基本了解. 相似文献
78.
In this paper, the integrals appeared in BEM model for Poisson equation are all implemented analytically. Wherein, the boundary
and the domain are discretized by linear boundary elements and linear internal triangle cells respectively. The closed formulations
for all integrals are presented so that the computer effort for numerical solution is reduced considerably with higher accuray.
The numerical example shows that the results are more accurate in comparision with Gaussian integration in the same discrezition.
The basic idea of this paper could be extended to BEM model for Helmholtz equation and/or the time-dependent second other
differential equations.
Supported by the National Natural Science Foundation of China
Tang Shaowu: born in 1971, Ph. D. 相似文献
79.
80.
本文讨论利用初等行变换求行向量组的极大线性无关组的方法,澄清一些线性代数教学用书中存在的一种模糊认识,并给出修正后的方法。 相似文献