检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

N_5H_5的结构性能的量子化学研究

四川大学学报（自然科学版） 2009年第4期46卷 1089-1095页

作者：毛双谭英雄蒲雪梅李来才田安民四川师范大学化学学院成都610068 四川大学化学学院成都610064

采用了密度泛函 B3LYP 方法在6-311++G^(**)基组上对 N_5H_5异构体进行了理论计算,得到7种稳定构型,应用自然键轨道理论(NBO)和分子中的原子理论(AIM)分析了这些异构体的成键特征、相对稳定性.N—N键的键长与键临界点的电荷密度存在线... 详细信息

采用了密度泛函 B3LYP 方法在6-311++G^(**)基组上对 N_5H_5异构体进行了理论计算,得到7种稳定构型,应用自然键轨道理论(NBO)和分子中的原子理论(AIM)分析了这些异构体的成键特征、相对稳定性.N—N键的键长与键临界点的电荷密度存在线性关系,键临界点的电荷密度ρ越大,N—N键的键长就越短.N 原子孤对电子与相邻的氮氮键之间的相互作用是影响氮氮键长变化的主要因素.立体交换排斥能和离域化能是影响异构体相对稳定性的重要因素.G3MP2.算结果表明所有异构体的生成热均为正,环状异构体的能量和生成热高于链状异构体.

关键词：氮氢化合物密度泛函理论相对稳定性生成热

Theoretical study of the potential energy surface and the highly excited rovibra-tional spectroscopy of H_2. molecule

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2001年第8期46卷 650-652页

作者： XIE Junkai & YAN Guosendepartment of chemistry, {2. Normal university, chengdu 610066, china department of chemistry, sichuan university, chengdu 610064, china department of chemistry Sichuan Normal University Chengdu China department of chemistry Sichuan University Chengdu China

This note reports the potential energy surface of H2. that has been refined by using SCF-CI approach and the high-resolution experimental data. The calculated splitting values of the local mode vibration states pair close to observed values. This vibration state calculation has shown that there are no obvious non-Born Oppenheimer effects occurring in the lower vibration states of the system.

关键词： potential energy surface local mode vibration state non- Born Oppenheimer effect.

APPLICATIONS OF THE THEORY OF CAMINA GROUPS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 1999年第1期20卷 39-50页

作者： REN YONGCAI(department of Mathematics,sichuan Union {2.,chengdu 610064,china) department of Mathematics Sichuan Union University Chengdu 610064 China

In this papert the author first gives a conjugacy-class version of Camina hypotheses andthen applys the Camina group theory to discussing two classes of finite groups.

关键词： Camina groups Applications Characters

TOEPLITZ OPERATORS AND ALGEBRAS ON DIRICHLET SPACES

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2002年第3期23卷 385-396页

作者： CAO GUANGFU department of Mathematics, sichuan university,{2., china. department of Mathematics Sichuan University Chengdu 610064 China

The automorphism group of the Toeplitz C^*- algebra, J(C^1), generated by Toeplitz op-erators with C^1-symbols on Dirichlet space D is discussed; the K0, K1-groups and the first cohomology group of J(C^1) are computed. In addition, the author proves that the spectra of Toeplitz operators with C^1-symbols are always connected, and discusses the algebraic prop-erties of Toeplitz *** particular, it is proved that there is no nontrivial selfadjoint Toeplitz operator on D and Tψ^* = Tψ^- if and only if Tψ is a scalar operator.

关键词： Dirichlet space Toeplitz operator Toeplitz algebra

γ-Hydroxy-α,β-acetylenic esters:asymmetric syntheses and applications

在线全文

学校读者我要写书评

暂无评论

Science china chemistry 2010年第1期53卷 21-35页

作者： GAO Ge1 & PU Lin2.1department of chemistry,{2. university,chengdu 610064,china 2.0} of chemistry,university of Virginia,Charlottesville,Virginia 2.904-4319,USA department of chemistry Sichuan University Chengdu China department of chemistry University of Virginia Charlottesville USA

γ-Hydroxy-α,β-acetylenic esters are versatile synthetic precursors to many organic *** paper reviews the synthesis of chiral γ-hydroxy-α,β-acetylenic esters by asymmetric reduction of γ-oxo-α,β-acetylenic esters,enantioselective addition to aldehydes in the presence of chiral catalysts,and diastereoselective addition to chiral *** preparation of racemic γ-hydroxy-α,β-acetylenic esters is also *** are provided for the application of γ-hydroxy-α,β-acetylenic esters in organic synthesis.

关键词： γ-hydroxy-α β-acetylenic ester asymmetric enantioselective diastereoselective

Uniform asymptotic stability in functional differential equations with infinite delay

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第12期43卷 1000-1003页

作者： XU Anshi department of Mathematics, sichuan university,{2., china department of Mathematics Sichuan University Chengdu China

The fading memory space is used as phace space, and Liapunov methods are used to give conditions ensuring that the zero solution of functional differential equations with infinite delay is uniformly asymptotically sta... 详细信息

关键词： functional differential equation integral-differential equation fading memory space uniform asymptotic stalility.

Statistical properties for the vibrational energy levels of OCS

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第8期47卷 641-643页

作者： XIE Daiqian & LU YuhuiInstitute of Theoretical and Computational chemistry, department of chemistry, Nanjing university, Nanjing 2.0093, china department of chemistry, sichuan university, chengdu 610064, china Institute of Theoretical and Computational chemistry Department of Chemistry Nanjing University Nanjing China department of chemistry Sichuan University Chengdu China

A potential energy surface for the electronic ground state of carbonyl sulfide was optimized by using a self-consistent configuration-interaction method and involving the recently observed vibrational band origins up to 8000 cm-1. With the optimized potential, the vibrational energy levels of OCS up to 15000 cm-1 were computed using the discrete variable representation method and Lanczos algorithm. Approximately 480 vibrational energy levels were identified. The statistical investigation showed that the vibrational energy levels of OCS up to 15000 cm-1 are largely regular.

关键词： OCS potential energy surface vibrational spectra sta-tistical property.

Theoretical study on the hydrolysis mechanism of N,N-dimethyl-N′-(2.,3′-dideoxy-3′-thiacytidine)formamidine

在线全文

学校读者我要写书评

暂无评论

Science china chemistry 2008年第10期51卷 911-917页

作者： ZHANG Chang1 & XUE Ying2. 1 College of chemistry and Environment Protection Engineering, Southwest university for Nationalities, {2. 610041, china 2.College of chemistry, sichuan university, chengdu 610064, china College of chemistry and Environment Protection Engineering Southwest University for Nationalities Chengdu China College of chemistry Sichuan University Chengdu China

The hydrolysis mechanisms of N,N-dimethyl-N′-(2.,3′-dideoxy-3′-thiacytidine)formamidine (FA-3TC) in the gas phase and in aqueous solution were studied by use of the density functional theory B3LYP/6-31+G(d, p) method. Two possible reaction pathways in the title reaction were considered. In one pathway water attacks the C=N double bond first (path A) while in the other water attacks the C—N single bond first (path B). The calculated results indicate that the first step in both pathways is the rate-limiting process and path A is more favorable than path B in the gas phase. The effect of solvent water on the title reaction was assessed at the B3LYP/6-31+G(d, p) level of theory based on the po-larizable continuum model (CPCM). In water the first mechanism (path A) is also favored.

关键词： N N-dimethyl-N′-(2. 3′-dideoxy-3′-thiacytidine)formamidine hydrolysis solvent effect B3LYP polarizable continuum model

On nulls of perturbed Fredholm operators and degenerate homoclinic bifurcations

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2004年第4期47卷 617-627页

作者： ZHANG Weiniandepartment of Mathematics, sichuan university,{2., china department of Mathematics Sichuan University Chengdu China

It is known that small perturbations of a Fredholm operatorL have nulls of dimension not larger than dimN(L). In this paper for any given positive integer κ ? dimN(L) we prove that there is a perturbation ofL which has an exactly κ-dimensional null. Actually, our proof gives a construction of the perturbation. We further apply our result to concrete examples of differential equations with degenerate homoclinic orbits, showing how many independent homoclinic orbits can be bifurcated from a perturbation.

关键词： Fredholm operator, perturbation, dimension, decomposition, degenerate homoclinic bifurcation.