检索结果-南通市图书馆

Theoretical study of ZnO adsorption and bonding on Al_2._3.0001) surface

Science china(physics,Mechanics & Astronomy) 2004年第6期47卷 664-675页

作者： LI Yanrong1,YANG Chun1,2.XUE Weidong1,LI Jinshan3.& LIU Yonghua3.1.{2. of Microelectronics and Solid State Electronics,University of Electronic Science and Technol- ogy of china,Chengdu 610054,china 2.{2. of Mathematics and Software Science,Sichuan Normal University,Chengdu 610068,china 3.institute of chemical Materials,china Academy of engineering physics,{12.,china institute of Microelectronics and Solid State Electronics University of Electronic Science and Technology of China Chengdu 610054 China institute of Mathematics and Software Science Sichuan Normal University Chengdu 610068 China institute of chemical Materials China Academy of Engineering Physics Mianyang 621000 China

ZnO adsorption on sapphire (0001) surface is theoretically calculated by using a plane wave ultrasoft pseudo-potential method based on ab initio molecular dynamics. The results reveal that the surface relaxation in the first layer Al-O is reduced, even eliminated after the surface adsorption of ZnO, and the chemical bonding energy is 43..3.±3..6) kJ·mol?1. The chemical bond of ZnO (0.185 ± 0.01 nm) has a 3.° angle away from the adjacent Al-O bond, and the stable chemical adsorption position of the Zn is deflected from the surface O-hexagonal symmetry with an angle of about 3.°. The analysis of the atomic populations, density of state and bonding electronic density before and after the adsorption indicates that the chemical bond formed by the O2.of the ZnO ? and the surface Al3. has a strong ionic bonding characteristic, while the chemical bond formed by the Zn2. and the surface O2.has an obvious covalent characteristic, which ? comes mainly from the hybridization of the Zn 4s and the O 2. and partially from that of the Zn 3. and the O 2..

关键词： α-Al2.3.(0001) ZnO ab initio molecular dynamics chemical adsorption density of states

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Electronic structure and magnetism of R(Fe,Si)_(12. (R=Y,Nd)

引用

Science china(physics,Mechanics & Astronomy) 2006年第2期49卷 195-202页

作者： SUN Guang’ai1, CHEN Bo1, DU Honglin2. FAN Zhijian1, GAO Tao3.& QI Xinhua3.. {2. of Nuclear physics and Chemistry, china Academy of {3. physics, mianyang 62.900, china 2. Department of physics, Peking university, Beijing 100871, china 3. {2. of Atomic and Molecular physics, Sichuan University, Chengdu 610065, china institute of Nuclear physics and Chemistry China Academy of Engineering Physics Mianyang China Department of physics Peking university Beijing China institute of Atomic and Molecular physics Sichuan University Chengdu China

The newly developed full-potential linearized augmented plane wave (LAPW) and local orbitals (lo) based on standard APW methods are briefly introduced, and the structure and magnetic properties of R(Fe, Si)12.compounds (R = Y, Nd) are calculated using the method. The distribution of Si at different sites is analyzed based on total energy of one crystal unit with structure having been optimized. The characters of magnetic mo-ments, total density of states (TDOS) and partial density of states (PDOS) for different crystal sites Si occupies are obtained and analyzed. The results show that the total mag-netic moments of RFe10Si2.(R = Y, Nd) are larger than those of RFe10M2.(M = Ti, V, Cr, Mn, Mo and W) and the hybridization mechanism is seen as follows. Si(8j) reduce the mag-netic moments of Fe at three sites, however, Si(8f) mainly reduce the magnetic moments of Fe(8i) and Fe(8j) atoms. The Curie temperature is markedly enhanced by the introduc-tion of Si atoms according to spin fluctuation of DOS at Fermi level.

关键词： (L)APW+lo method R(Fe Si)12.R = Y Nd) magnetic moment Density of state.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of N_(2.molecule

引用

Science china(physics,Mechanics & Astronomy) 2005年第4期48卷 385-398页

作者： REN Weiyi1,2. SUN Weiguo1, HOU Shilin3.& FENG Hao4 1. institute of {2., College of chemical {3., Sichuan University, Chengdu 610065, china 2. institute of Theoretical {2., Xihua Normal University, Nanchong 63.002. china 3. Department of {2., china Oceanography University, Qingdao 2.6003. china 4. College of {2., Sichuan University, Chengdu 610065, china institute of physics College of Chemical Engineering Sichuan University Chengdu China institute of Theoretical physics Xihua Normal University Nanchong China Department of physics China Oceanography University Qingdao China College of physics Sichuan University Chengdu China

It is usually very difficult to directly obtain molecular dissociation energy De and all accurate high-lying vibrational energies for most diatomic electronic states using modern experimental techniques or quantum theories, and it is also very difficult to give accurate analytical expression for diatomic molecular dissociation energy. This study proposes a new analytical formula for obtaining accurate molecular dissociation energy based on the LeRoy and Bernstein’s energy expression in dissociation limit. A set of full vibrational energy spectra for some electronic states of N2.molecule are studied using the algebraic method (AM) suggested recently, and the corresponding accurate molecular dissociation energies are evaluated using the proposed new formula and high-lying AM vibrational energies. The results show that the AM spectra and the new theoretical dissociation energies agree excellently with experimental data, and thereby providing a new physical approach to generating accurate dissociation energies for electronic states of diatomic molecules.

关键词： vibrational energy, dissociation energy, nitrogen molecule, algebraic method.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ab initio Calculation of Intermolecular Dispersion Energy and Induction Energy of Nitramide Dimer

引用

Chinese Journal of Chemistry 2004年第11期22卷 1377-1381页

作者：宋华杰肖鹤鸣董海山institute of chemical Materials {2. Academy of {3. physics mianyang Sichuan 62.900 {2. 黄奕刚institute of chemical Materials {2. Academy of {3. physics mianyang Sichuan 62.900 {2. 龙新平institute of chemical Materials {2. Academy of {3. physics mianyang Sichuan 62.900 {2. 汤业鹏institute of chemical Materials {2. Academy of {3. physics mianyang Sichuan 62.900 {2. Department of Chemistry Nanjing University of Science and Technology Nanjing Jiangsu 210094 China institute of chemical Materials China Academy of Engineering Physics Mianyang Sichuan 621900 China

The dispersion energies, induction energies and their exchange counterparts (exchange-dispersion and ex-change-induction energies) between two interacting nitramide molecules at several separations are derived based upon symmetry-adapted perturbation theory (SAPT). The results show that (1) the effect of intramonomer electron correlation on dispersion energies and induction energies for nitramide dimer system is remarkable especially in the region near the van der Waals minimum distance (0.42.nm). (2. At smaller separations the dispersion energies and the induction energies are largely quenched by their exchange counterparts, and this case in induction interaction is much more remarkable than in dispersion interaction. (3. Since at shorter distances there exists the strong short-range interaction due to electron transfer which quickly decays and even disappears at larger separations, the two different R-dependency formulae of induction energies were found: one is ca. R-12.7 at short distances, and the other ca. R-7.0 at large separations. The latter R-dependency is similar to that (ca. R-7.2. of dispersion. (4) In the case of strong polar interaction existing in nitramide dimer, the true induction correlation terms of higher order than t(2.)indE may be important.

关键词： dispersion energy induction energy nitramide dimer symmetry-adapted perturbation theory

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Studies on the analytical potential energy function of diatomic molecular ion XY^+ using variational method

引用

Science china(physics,Mechanics & Astronomy) 2004年第2期47卷 154-164页

作者： LIU Guoyue1,3. SUN Weiguo1,2.& FENG Hao1 1. institute of {2., Sichuan University, Chengdu 610065, china 2. College of {3. engineering, Sichuan University, Chengdu 610065, china 3. mianyang Teacher抯 College, mianyang 62.000, china Correspondence should be addressed to Sun Weiguo (e-mail: weiguosun@*** or guoyueliu@ ***) institute of physics Sichuan University Chengdu China mianyang Teacher's College Mianyang China College of chemical engineering Sichuan University Chengdu China

A new analytical potential energy function for diatomic molecular ion XY+ is proposed based on the energy consistent method (ECM). The Coulomb potential included in the new ionic potential contains multipole corrections, converges quickly and is variationally, changeable. The new potential and the ECM are applied to variationally studying the potential energies of eight electronic states of several diatomic molecular ions: the A2. state of CO+, the X2. g + state of Li 2.+ , the X2. g + state of He 2.+ , the 12.u state of Na 2.+ , the A2.u state of N 2.+ , the X1∑+ state of KrH+, the X2.+ state of SiO+ and the A2. state of SO+ ion. The present results agree excellently with the experiment-based Rydberg-Klein-Rees (RKR) potentials, and are superior to the commonly used Huxley-Murrell-Sorbie (HMS) analytical potentials, and are better in some cases than some quantum mechanicalab initio potentials in the ionic asymptotic and dissociation regions.

关键词： potential energy, diatomic ion, electronic state, variational method.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On-line parallel reversed phase two-dimensional liquid chromatography for high-throughput analysis of complex proteomic samples

引用

Science china Chemistry 2006年第6期49卷 527-533页

作者： WANG Zhicong1,3. ZHANG Qinghe2. LI Tong2. ZHAO Zhongyi3.& ZHANG Weibing1 1. Dalian {2. of chemical physics, Chinese Academy of Sciences, Dalian 116011, {3. 2. Dalian Elite Analytical Instrument Co., Ltd., Dalian 116011, {3. 3. Faculty of Material Science and chemical engineering, {3. University of Geosciences, Wuhan 43.074, {3. Dalian institute of chemical {2. Chinese Academy of Sciences Dalian China Faculty of Material Science and chemical engineering China University of Geosciences Wuhan China Dalian Elite Analytical Instrument Co. Ltd. Dalian China

A comprehensive two-dimensional liquid chromatographic system (2. SCX/RP) is con- structed with a 10-port-2.way valve using strong cation exchange chromatography (Hypersil SCX, 100 mm×4.6 mm I.D.) followed by reversed phase chromatography (Hypersil BDS C18, 15 mm×4.6 mm I.D.) to separate the complex peptides from globin peptic hydrolysate. After the sample was loaded on the SCX column, the phosphate buffer (pH 4.0) was used to elute the peptides. Then, elutes flowed through the interface and the peptides focused on the head of the trapping columns (Hypersil BDS C18, 15 mm×4.6 mm I.D.) but salt passed into the waste. After the valve was switched, the samples were flushed with a backward flow into the RP analytical column. The peptides on the SCX were eluted with 12.discontinuous steps linearly increasing salt concentrations. The peptides enriched on the trapping column were desalted and separated by the RP columns. The resolution and the resolved peaks of the 2. SCX/RP system were greatly increased and the total peak capacity reached as high as 2.80.

关键词： two-dimensional liquid chromatography, interface, trapping column, proteomics, globin.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

引用

Science china Chemistry 2004年第6期47卷 466-479页

作者： SONG Huajie1,2. XIAO Heming1 & DONG Haishan2.1. Department of Chemistry, Nanjing University of Science and Technology, Nanjing 2.0094, china 2. institute of {2. Materials, china Academy of engineering physics, mianyang 62.900, china Department of Chemistry Nanjing University of Science and Technology Nanjing China institute of chemical Materials China Academy of Engineering Physics Mianyang China

The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the diffi- culty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2. HF2.and (N2.2.and a set of larger ni- tramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capa- ble of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially pro- vides a good means to calculate accurately intermolecular forces in larger system such as en- ergetic systems.

关键词： intermolecular interaction, density functional theory (DFT), symmetry adapted perturbation theory (SAPT), asymptotic correction, frequency-dependent density susceptibilities (FDDS).

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Molecular dynamics simulations on the structures and properties of ε-CL-2.-based PBXs ——Primary theoretical studies on HEDM formulation design

引用

Science china Chemistry 2007年第6期50卷 737-745页

作者： XU XiaoJuan1,2. XIAO JiJun1, HUANG Hui3. LI JinShan3.& XIAO HeMing1 1 Department of Chemistry, Nanjing University of Science and Technology, Nanjing 2.0094, {2. 2.Department of Chemistry, Yancheng Teacher’s College, Yancheng 2.4002. {2. 3.institute of {3. Materials, {2. Academy of engineering physics, mianyang 62.900, {2. Department of Chemistry Nanjing University of Science and Technology Nanjing China Department of Chemistry Yancheng Teacher’s College Yancheng China institute of chemical Materials China Academy of Engineering Physics Mianyang China

Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-2.(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703.GAP,HTPB,PEG,and F_(2.0}4))were *** dynamics(MD)method was employed to investigate their binding energies(E_(bind))2./PEG 2./ Estane5703.≈ epsilon-CL-2./GAP 2./HTPB 2./F_(2.0}4).By pair correlation function g(r)analyses,hydrogen bonds and vdw are found to be the main interactions between the two *** elasticity and isotropy of PBXs based epsilon-CL-2. can be obviously improved more than pure epsilon-CL-2. *** is not by changing the molecular structures of epsilon-CL-2. for each binder to affect the *** safety and energetic properties of these PBXs are mainly influenced by the thermal capability(C_p^(deg))and density(p)of binders,respectively.

关键词： high energy density material (HEDM), hexanitrohexaazaisowurtzitane (CL-2.), polymer bonded explosives (PBXs), molecular dynamics (MD), compatibility, safety properties, mechanical properties, energetic properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical and experimental investigation of the fracture behavior of shock loaded alumina

引用

Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 244-252页

作者： REN HuiLan1,SHU XueFeng2.& LI Ping3.1 State Key Laboratory of Explosion Science and Technology,Beijing institute of Technology,Beijing 100081,{2. 2.institute of Applied Mechanics and Biomedical {3.,Taiyuan University of Technology,Taiyuan 03.02.,{2. 3.Labroratory for Shock Wave and Detonation physics Research,institute of Fluid physics,CAEP,mianyang 610059,{2. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing China institute of Applied Mechanics and Biomedical engineering Taiyuan University of Technology Taiyuan China Labroratory for Shock Wave and Detonation physics Research Institute of Fluid Physics CAEP Mianyang China

Plate impact expeiments are conducted to investigate the dynamic behavior of alumina by using one stage light gas gun. A ve-locity interferometer system for reflectors (VISAR) is used to obtain Hugoniot elastic limit and the free surface velocity profile,which consists of an elastic wave followed immediately by a dispersive inelastic wave. The stress histories under different impact velocities are measured by in-material manganin gauges. Based on the experimental data a Hugoniot curve is fitted,which shows the compressive characteristics that alumina changes typically from elastic to "plastic" ,and under higher pressure it will be transferred to similar-fluid state. The turning point of the Hugoniot curve from a high pressure region to a low pressure region is about 11.4 GPa. The fracture process of alumina is simulated by way of finite element code. After the analysis of the fracture mechanism,the numerical results show an important role played by the nucleation and the growth of the cracks in the macro-scopic fracture of the alumina target. The numerical predictions of stress histories are compared with the experimental results,which indicates consistency between them.

关键词： plate impact experiment hugoniot curve fracture characteristics numerical simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An efficient chiral synthesis of (R)-N-[3.acetyl-4-(2.hydroxy-3.isopropylamino-propoxy)phenyl]-butanamide with high enantioselectivity

引用

Science china Chemistry 2009年第8期52卷 1216-1219页

作者： WANG NaiXing1,2.& TANG XinLiang1,3.1 Technical institute of {2. and Chemistry,Chinese Academy of Sciences,Beijing 100080,china 2.College of Chemistry and {3. engineering,Graduate University of Chinese Academy of Sciences,Beijing 100049,china 3.School of {3. engineering and Environment,Beijing institute of Technology,Beijing 100081,china Technical institute of physics and Chemistry Chinese Academy of Sciences Beijing China College of Chemistry and chemical engineering Graduate University of Chinese Academy of Sciences Beijing China School of chemical engineering and Environment Beijing Institute of Technology Beijing China

R-Enantiomer of the β-receptor antagonist N-[3.acetyl-4-(2.hydroxy-3.isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** product was detected by 1H NMR,13. NMR,and MS,and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HPLC analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：