激发态的相关基函数理论

本文根据相关基函数理论建立了电子相互作用体系的激发态理论。在Chakravarty-Woo方程的基础上,利用泛函展开和卷积近似得到了单粒子激发而引起的电子密度分布和关联函数变化的自洽方程。由多体理论的激发能的定义出发,求得了导电聚合物(考虑了电子相互作用)的能隙公式,在已知的参数下,给出了与实验相符的结果。

精确计算氢键结合能的相关一致性基函数两点外推法

为了获得精确的氢键结合能并减小计算需求,在CCSD(T)水平下使用了一种基于相关一致性基函数的简单两点外推公式。为了提高氢键结合能的精确度,在公式中增加了一个变量。根据10个氢键体系分析的结果显示,使用基函数aug-cc-pVDZ和aug-cc-pVTZ计算所得总能量之差与变量存在线性关系,进而得到新的外推公式。从用于测试的18个氢键体系的数据显示,由这种外推方法获得的氢键结合能与使用基函数aug-cc-pVQZ计算所得结果能够很好的吻合。

Prediction of the Helix/Sheet Content of Proteins from Their Primary Sequences by Neural Network Method

The amino acid composition and the biased auto-correlation function are considered as features, BP neural network algorithm is used to synthesize these features. The prediction accuracy of this method is verified by using the independent non-homologous protein database. It is shown that the average absolute errors for resubstitution test are 0.070 and 0.068 with the standard deviations 0.049 and 0.047 for the prediction of the content of α-helix and β-sheet respectively. For cross-validation test, the average absolute errors are 0.075 and 0.070 with the standard deviations 0.050 and 0.049 for the prediction of the content of α-helix and β-sheet respectively. Compared with the other methods currently available, the BP neural network method combined with the amino acid composition and the biased auto-correlation function features can effectively improve the prediction accuracy.

Mean Residence Time of CO2 Molecules in Flexible ZIF-8 Cages Explored by Molecular Dynamics Simulations

The adsorption sites and diffusion mechanism of CO2 molecules in the flexible Zn（MeIM）2 （MeIM=2-methylimidazole） （ZIF-8） have been investigated by grand canonical Monte Carlo and molecular dynamics simulations. A reasonable time correlation function is for the first time constructed to explore the mean residence time of CO2 molecules in the ZIF-8 cages, suggesting that C02 molecules can remain in the same cage for up to several tens of picoseconds. Furthermore, we find that the mean residence time almost linearly increases with the increasing pressure （or loading） at 273 and 298 K.

Defeating constraint based program analysis with temporal correlation function

Constraint based program analysis is widely used in program validation, program vulnerability analysis, etc. This paper proposes a temporal correlation function to protect programs from analysis. The temporal correlation function can be applied to resist against both static and dynamic function summary and eoncolie testing. What＇ s more, the temporal correlation function can produce different outputs even with same input. This feature can be used to damage the premise of function summary as well as prevent concolie testing process to run the new branch with new input. Experiment results show that this method can reduce efficiency and path coverage of concolic testing, while greatly in- creasing the difficulty of constraint based program analysis.

Statistics and Correlation Properties of Diamagnetic High Rydberg Hydrogen Atom

The spectra of Rydberg hydrogen atom in magnetic fields have been calculated using linear variational method with B-splines basis functions [Acta Phys. Sin. 55 （2006） 3380]. Based on these calculations we have done some statistics analysis about the high Rydberg energy levels. The nearest-neighbor energy spacing distribution and the 3-statistics have been shown about diamagnetic Rydberg hydrogen atom with the magnetic field being 0.6 T and 6 T. The phenomena of multiply crossing, multiply anti-crossing, and the mixed of crossing and anti-crossing of energy levels have appeared in this paper. For both cases, in range of lower energy, the energy 1evel statistics properties close to Poisson distribution. With the increasing of the energy, the energy level statistics properties are away to Poisson distribution and tend to Wigner distribution step by step.

TinII intron, an enhancer to affect the function of the cytoplasmic male sterility related gene T in Brassica juncea

The T gene, which was cloned from the mitochondria of tumorous stem mustard （Brassica juncea var. tumida）, is a cytoplas- mic male sterility （CMS）-related gene that can produce two transcripts, T1170 and T1243. The latter is transcribed with the un- cleaved intron Tinll. In our previous study, transgenic Arabidopsis thaliana plants over-expressing the T1243 transcript （OE-T1243） showed a severe male-sterile phenotype, whereas OE-Tll70 plants did not. However, the functional mechanism of the T gene in B. Juncea remained unknown. In this study, microscopic analyses of paraffin sections of anthers confirmed that OE-T1243 plants did not produce normal pollen, whereas OE-T1170 plants did. We analyzed the transcription of 15 anther development-related genes and found that transcript levels of nozzle/sporocyteless and barely any meristem 1 and 2 were markedly lower in OE-T1243 plants than those in wild type, while the transcript levels of these genes in OE-Tll70 plants were unchanged. To investigate the potential roles of TinH, we inserted the TinH sequence upstream of a minimal region （-60） of the cauliflower mosaic virus 35S promoter fused to the 5＇ end of the 13-glucuronidase （GUS） reporter gene. Analysis of the transgenic plants suggested that TinH acted as an enhancer to significantly increase GUS expression. The potential action mechanism is that the TinH intron acts as an enhancer to affect the function of the CMS-related gene T.