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Molecular dynamics simulations on the structures and properties of ε-CL-20-based PBXs ——Primary theoretical studies on HEDM formulation design

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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 210094, china 2 Department of chemistry, Yancheng Teacher’s college, Yancheng 224002, china 3 Institute of chemical Materials, china Academy of engineering Physics, Mianyang 621900, china Department of chemistry Nanjing University of Science and TechnologyNanjing 210094China Department of chemistry Yancheng Teacher''s CollegeYancheng 224002China Institute of chemical Materials China Academy of Engineering PhysicsMianyang 621900

Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-20(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703,GAP,HTPB,PEG,and F_(2314))were *** dynamics(MD)method was employed to investigate their binding energies(E_(bind))20/PEG 20/ Estane5703 ≈ epsilon-CL-20/GAP 20/HTPB 20/F_(2314).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-20 can be obviously improved more than pure epsilon-CL-20 *** is not by changing the molecular structures of epsilon-CL-20 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-20), polymer bonded explosives (PBXs), molecular dynamics (MD), compatibility, safety properties, mechanical properties, energetic properties

Predicting bioconcentration factor values of organic pollutants based on medv descriptors derived QSARs

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Science china chemistry 2007年第5期50卷 587-592页

作者： CUI ShiHai1,2, YANG Jing1, LIU ShuShen2,3 & WANG LianSheng2 1 college of chemistry and Environment, nanjing Normal university, nanjing 210097, china 2 State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, nanjing university, nanjing 210093, china 3 Key Laboratory of Yangtze Aquatic Environment, Ministry of Education, college of Environmental Science and engineering, Tongji university, Shanghai 200092, china 1. college of chemistry and Environment Nanjing Normal University Nanjing 210097 China 2. State Key Laboratory of Pollution Control and Resources Reuse School of the Environment Nanjing University Nanjing 210093 China 3. Key Laboratory of Yangtze Aquatic Environment Ministry of Education College of Environmental Science and Engineering Tongji University Shanghai 200092 China

The molecular electronegativity-distance vector (MEDV) is employed todescribe the chemical structure of organic *** linear relationships between themolecular descriptors and BCF values are developed by best subset regression and partial leastsquare regression *** main structural factors influencing the bioactivities are -CH2,-X,-Cnot 2 and q2_(LOO) present good estimation ability and stabilityof *** prediction power for external samples is validated by the model developed from thetraining set.

关键词： POPs, BCF, MEDV, QSAR

Mathematic Expression of Kinetic Compensation Effect and Relationship between the Exothermic Decomposition Temperature and Critical Temperature of Thermal Explosion of Eighty-six Energetic Materials

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含能材料 2001年第1期9卷 8-9页

作者： HU Rong zu 1, YANG De suo 2, ZHANG Jiao qiang 3 (1. Department of chemistry,Northwest university, Xi′an 710065, china 2. Department of chemistry and chemical engineering, Baoji college of Arts and Science, Baoji 721007, china 3. Department of 西北大学陕西西安 710065 宝鸡文理学院陕西 721007 西北工业大学陕西西安 710072

Two relationships are established using the least squares method,between the kinetic parameters (the apparent activation energy and pre exponential constant),and the exothermic decomposition temperature and ther... 详细信息

关键词： critical temperature of thermal explosion decomposition temperature DSC energetic materials.

Binaphthyl-bridged bis-imidazolinium salts as N-heterocyclic carbene ligand precursors in the palladium-catalyzed Heck reaction

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Science china chemistry 2011年第6期54卷 951-956页

作者： WU Hui, JIN Can, HUANG GuoLi, WANG LianJun, JIANG JuLi & WANG LeYong Key Laboratory of Mesoscopic chemistry of Ministry of Education School of chemistry and chemical engineering, nanjing university, nanjing 210093, china 1. Key Laboratory of Mesoscopic chemistry of Ministry of Education School of chemistry and chemical engineering Nanjing University Nanjing 210093 China

Two new bis-imidazolinium salts (4a, 4b) have been synthesized as precursors of N-heterocyclic carbenes (NHCs) from the commercially available (R)-2,2′-dihydroxy-1,1′-binaphthalene. The two bis-imidazolinium salts were used as efficient precursor of NHC ancillary ligands in the palladium-catalyzed Heck reaction. Good to excellent yields and high stereoselectivities were obtained with ethyl acrylate, acrylonitrile, and acrylamide as starting materials. The structure of bis-imidazolinium salt 4b was further characterized by single crystal X-ray diffraction analysis.

关键词： N-heterocyclic carbenes Heck reaction palladium imidazolinium salts

Electrophoretic Coating of Hydroxyapatite on Pyrolytic Carbon Using Glycol as Dispersion Medium

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Journal of Wuhan university of Technology(Materials Science) 2008年第3期23卷 293-297页

作者：高林 college of Life Science and Technology Huazhong University of Science and Technology college of chemistry and Environmental engineering Yangtze UniversityJingzhou 434023China

Hydroxyapatite （HA） coatings on pyrolytic carbon were produced via electrophoretic deposition （EPD） using glycol and ethanol as dispersion medium respectively. The effect of the solubility of HA in the dispersion medium on crack occurrence and adherence of the coating was investigated by means of scanning electronic microscope （SEM） and atomic absorption spectrometer （AAS）. The results show that the solubility of HA in glycol is higher than that in ethanol. The usage of glycol as a dispersion medium can reduce the possibility of crack formation and enhance the adhesive strength between the coating and the carbon substrate. The green coatings can be sintered under vacuum at 1 000 ℃ whether the coatings are obtained using ethanol or glycol as dispersion medium. No HA decomposition was observed up to 1 000 ℃ by vacuum sintering by X-ray diffraction （XRD） analysis.

关键词： hydroxyapatite electrophoretic deposition coatings dispersion medium glycol

AlkB recognition of a bulky DNA base adduct stabilized by chemical cross-linking

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Science china chemistry 2010年第1期53卷 86-90页

作者： YI ChengQi1 & HE Chuan1,2 1Department of chemistry,university of Chicago,Chicago,Illinois 60637,USA 2Department of chemical Biology,college of chemistry and Molecular engineering,Peking university,Beijing 100871,china 1. Department of chemistry University of Chicago Chicago Illinois 60637 USA2. Department of Chemical Biology College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

*** AlkB is a direct DNA/RNA repair protein that oxidatively reverses N1 alkylated purines and N3 alkylated pyrimidines to regular *** crystal structures have revealed N1-methyl adenine(1-meA) recognition by AlkB and a unique base flipping mechanism,but how the AlkB active site can accommodate bulky base adducts is largely *** a previously developed chemical cross-linking technique,we crystallized AlkB with a duplex DNA containing a caged thymine base(cagedT).The structure revealed a flexible hairpin lid and a reorganized substrate recognition loop used by AlkB to accommodate *** observations demonstrate,at the molecular level,how bulky DNA adducts may be recognized and processed by AlkB.

关键词： DNA/RNA repair AlkB caged thymine disulfide cross-linking bulky base adduct

Theoretical study of the mechanism for C-H bond activation in spin-forbidden reaction between Ti^+ and C_2H_4

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Science china chemistry 2009年第3期52卷 295-303页

作者： LV LingLing1, LIU XinWen1, YUAN Kun1, WANG XiaoFang1 & WANG YongCheng2 1 college of Life Science and chemistry, Tianshui Normal university, Tianshui 741001, china 2.college of chemistry and chemical engineering, Northwest Normal university, Lanzhou 730070, china college of Life Science and chemistry Tianshui Normal University Tianshui 741001 China college of chemistry and chemical engineering Northwest Normal University Lanzhou 730070 China

The mechanism of the spin-forbidden reaction Ti+(4F, 3d24s1) + C2H4 → TiC2H2+ (2A2) + H2 on both doublet and quartet potential energy surfaces has been investigated at the B3LYP level of theory. Crossing points between the potential energy surfaces and the possible spin inversion process are discussed by means of spin-orbit coupling (SOC) calculations. The strength of the SOC between the low-lying quartet state and the doublet state is 59.3 cm-1 in the intermediate complex IM1-4B2. Thus, the changes of its spin multiplicity may occur from the quartet to the doublet surface to form IM1- 2A1, leading to a sig-nificant decrease in the barrier height on the quartet PES. After the insertion intermediate IM2, two dis-tinct reaction paths on the doublet PES have been found, i.e., a stepwise path and a concerted path. The latter is found to be the lowest energy path on the doublet PES to exothermic TiC2H2+ (2A2) + H2 products, with the active barrier of 4.52 kcal/mol. In other words, this reaction proceeds in the following way: Ti++C2H4 →4IC→IM1-4B2→4,2ISC→IM1- 2A1→[2TSins]→IM2→[2TSMCTS]→IM5→TiC2H2+(2A2)+H2.

关键词： Ti+(4F) and C2H4 spin-forbidden reaction mechanism spin-orbit coupling (SOC) concerted path

Predicting neutron star spins from twin kHz QPOs

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 247-248页

作者： SHI ChangSheng Department of Astronomy,nanjing university,nanjing 210093,china college of Material Science and chemical engineering,Hainan university,Hainan 570228,china 1. Department of Astronomy Nanjing University Nanjing 210093 China

We briefly review the proposed relations between the frequencies of twin kilohertz quasi-periodic oscillations(kHz QPOs) and the spin frequencies in neutron star low-mass X-ray binaries(NSLMXBs).To test the validity of the proposed models,we estimate the spin frequencies under these theoretical relations and compare them with the measured *** seems that magnetohydrodynamic(MHD) oscillations are more promising to account for the kHz QPOs.

关键词： win kHz QPOs spin neutron stars LMXBs

Controlled synthesis and magnetic properties of Fe_3O_4 walnut spherical particles and octahedral microcrystals

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Science china(Technological Sciences) 2008年第11期51卷 1911-1920页

作者： JIAO Hua1,2 & YANG HeQing1 1 Key Laboratory of Macromolecular Science of Shaanxi Province, School of chemistry and Materials Science, Shaanxi Normal university, Xi’an 710062, china 2 Department of chemistry and chemical engineering, Weinan Teachers university, Wei nan 714000, china Key Laboratory of Macromolecular Science of Shaanxi Province School of Chemistry and Materials Science Shaanxi Normal University Xi’an 710062 China Department of chemistry and chemical engineering Weinan Teachers University Wei nan 714000 China

Magnetite Fe3O4 walnut spherical particles and octahedral microcrystals were suc- cessfully synthesized from K4 [Fe (CN) 6], K3 [Fe (CN) 6] and NaOH reagents via a simple hydrothermal process. And the uniform morphology of octahedral micro- crystals was obtained in the presence of ethylene glycol. The morphology and structure of products were characterized by powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the Fe3O4 walnut spherical particles and octahedral microcrystals were single crystals with the face-center cubic structure and with size distributions from 2.2 to 8.6 μm and 1.6 to 12.5 μm, respectively. Their magnetic properties were detected by a vibrating sample magnetometer at room temperature. The walnut spherical parti- cles exhibited a ferromagnetic behavior with the coercive force (Hc), saturation magnetization (Ms) and remanent magnetization (Mr) being 150.57 Oe, 97.634 and 12.05 emu/g, respectively. For the octahedral microcrystals they were 75.28 Oe, 101.90 and 6.69 emu/g, respectively. Different sizes of walnut spherical particles were controlled synthesized through adjusting the NaOH concentration. It was found that ethylene glycol molecules have a significant effect on the formation of Fe3O4 octahedra. A possible mechanism was also proposed to account for the growth of these Fe3O4 products

关键词： a hydrothermal route Fe3O4 walnut spherical particles octahedral microcrystals magnetic property