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Thermal oxide synthesis and characterization of Fe_3O_4.nanorods and Fe_2O_3 nanowires

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science china chemistry 2009年第5期52卷 599-604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 {4. engineering, weinan teacher’s university, weinan 714.00, china 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 Teacher’s University Weinan 714000 China

Fe3O4.nanorods and Fe2O3 nanowires have been synthesized through a simple thermal oxide reaction of Fe with C2H2O4.solution at 200-600℃ for 1 h in the air. The morphology and structure of Fe3O4.nanorods and Fe2O3 nanowires were detected with powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The influence of temperature on the morphology development was experimentally investigated. The results show that the polycrystals Fe3O4.nanorods with cubic structure and the average diameter of 0.5-0.8 μm grow after reaction at 200-500℃ for 1 h in the air. When the temperature was 600℃, the samples completely became Fe2O3 nanowires with hexagonal structure. It was found that C2H2O4.molecules had a significant effect on the formation of Fe3O4.nanorods. A possible mechanism was also proposed to account for the growth of these Fe3O4.nanorods.

关键词： thermal oxide process nanorods nanowires C2H2O4 iron sheet

Theoretical study of bifurcated bent blue-shifted hydrogen bonds CH_2…Y

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science china chemistry 2008年第7期51卷 623-631页

作者： LI AnYong school of chemistry and chemical engineering, southwest university, Chongqing 4.0715,{4. school of chemistry and chemical engineering Southwest UniversityChongqing 400715China

Ab initio quantum chemistry methods were applied to study the bifurcated bent hydrogen bonds Y… H2CZ (Z = O, s, se) and Y…H2CZ2 (Z = F, Cl, Br) (Y = Cl-, Br-) at the MP2/6-311++G(d,p) and MP2/6-311++G(2df,2p) levels. The results show that in each complex there are two equivalent blue-shifted H-bonds Y…H—C, and that the interaction energies and blue shifts are large, the energy of each Y…H—C H-bond is 15-27 kJ/mol, and Δr(CH) = -0.1 - -0.5 pm and Δv(CH) = 30 - 80 cm-1. The natural bond orbital analysis shows that these blue-shifted H-bonds are caused by three factors: large rehybridization; small direct intermolecular hyperconjugation and larger indirect intermolecular hy- perconjugation; large decrease of intramolecular hyperconjugation. The topological analysis of elec- tron density shows that in each complex there are three intermolecular critical points: there is one bond critical point between the acceptor atom Y and each hydrogen, and there is a ring critical point inside the tetragon YHCH, so these interactions are exactly H-bonding.

关键词： bifurcated bent H-bonds blue-shifted H-bonds topological property of electron density intramolecular hyperconjugation

Resolution of α-cyclohexyl-mandelic acid enantiomers by two-phase (O/W) recognition chiral extraction

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science china chemistry 2007年第6期50卷 764-769页

作者： TANG KeWen1,2, ZHANG GuoLi2, HUANG KeLong2, LI Yuanjian3 & YI JianMin1,2 1 Department of chemistry and chemical engineering, Hunan Institute of science and Technology, Yueyang 4.4.00, china 2 College of chemistry and chemical engineering, Central south university, Changsha 4.0083, china 3 College of Pharmaceutical science, Central south university, Changsha 4.0078, china Department of chemistry and chemical engineering Hunan Institute of Science and TechnologyYueyang 414000China College of chemistry and chemical engineering Central South UniversityChangsha 410083China

This paper presents a new chiral separation technology:two-phase(O/W)recognition chiral *** behavior of alpha-cyclohexyl-mandelic acid enantiomers was studied in the extraction system with D(L)-isobutyl tartrate in 1,2-dichloroethane organic phase and beta-CD derivatives in aqueous phase,and the influence of the kind and concentration of extractant and pH on extraction performance was *** experimental results indicate that two-phase(O/W)recognition chiral extraction is of strong chiral separation ***-^-CD,HE-beta-CD and Me-beta-CD have higher recognition ability for s-CHMA than that for R-CHMA,among which HP-beta-CD has the strongest ability;whereas,D-isobutyl tartrate has reversed recognition ability for *** the extraction system containing HP-beta-CD and D-isobutyl tartrate,e.e.% of s-CHMA in aqueous phase reached 27.6% by one stage extraction,and the distribution ratio for R-CHMA(k_R)and for s-CHMA(k_s)and separation factor(alpha)are 2.4.,0.89 and 2.4.,***,pH and concentration of extractant have great effects on chiral separation ***-phase(O/W)recognition chiral extraction has great significance for preparative separation of racemic compounds.

关键词： two-phase(W/0)recognition chiral extraction alpha-cyclohexyl-mandelic acid enantiomers

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VIsCOsITY OF DILUTE POLYMER sOLUTION

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Chinese Journal of Polymer science 2000年第1期18卷 57-67页

作者： Yan Pan Rong-shi Cheng College of Material science and engineering, south china university of Technology, Guangzhou 51064., china College of {4. and chemical engineering, Nanjing university, Nanjing 210093, china s china Univ Technol Coll Mat Sci & Engn Guangzhou 510641 Peoples R China Nanjing Univ Coll Chem & Chem Engn Nanjing 210093 Peoples R China

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration C-s(dynamic contact concentration) which divides the dilute polymer solution into two regions.

关键词： self-association polymer solution viscosity concentration dependence

study on Enhancement in Gibbsite Precipitation of Bayer Process under 33 kHz Ultrasound

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Journal of Materials science & Technology 2003年第6期19卷 607-610页

作者： Jihua ZHAO and Qiyuan CHENCollege of chemistry and chemical engineering, Central south university, Changsha 4.0083,{4.College of chemistry and chemical engineering, Lanzhou university, Lanzhou 730000,{4. Cent s Univ Coll Chem & Chem Engn Changsha 410083 Peoples R China Lanzhou Univ Coll Chem & Chem Engn Lanzhou 730000 Peoples R China

The enhancement of gibbsite precipitation in Bayer process by 33 kHz ultrasound has been studied. From orthome-thod experiment, the optimized operating parameters of treatment under 33 kHz ultrasonic cleaner have obtained. Compared with crystallization of AI(OH)3 without treatment of ultrasound, the precipitation time is reduced by 15 h when the precipitation ratio is 4.%. From the results of grain size distribution and sEM photographs of gibbsite, it is found that secondary nucleation and agglomeration could be enhanced under 33 kHz ultrasound. The products are same from comparison of X-ray powder diffraction, but the Raman spectrum of sodium aluminate solution under 33 kHz ultrasound is different from that without ultrasound.

关键词： Ultrasound Aluminium trihydroxide Precipitation

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 {4.’s College, Yancheng 224.02, 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))safety,mechanical properties,and energetic *** information and rules were reported for choosing better binders and guiding formulation design of high energy density material(HEDM).According to the calculated binding energies,the ordering of compatibility and stability of the five PBXs was predicted as epsilon-CL-20/PEG silon-CL-20/ Estane5703 ≈ epsilon-CL-20/GAP silon-CL-20/HTPB silon-CL-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

Meet Our New Editorial Board Members of spotlights

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Chinese Journal of chemistry 2024年第16期42卷 1932-1936页

作者： Editorial Office of Chinese Journal of chemistry 不详

Editorial Board Member of *** ***,College of Materials science and engineering Beijing university of chemical ***:2006-2010,B.s.,Materials science and engineering,Beijing university of chemical Technology.2010-2015,Ph... 详细信息

关键词： spotlight Editorial Board

Meet Our New Associate Editors

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Chinese Journal of chemistry 2024年第11期42卷 1319-1321页

作者： Editorial Office of Chinese Journal of chemistry 不详

Associate Editor Dehui Deng Professor The state Key Laboratory of Catalysis Dalian Institute of chemical Physics,Chinese Academy of sciences,china(+86)04.1-824.3870,dhdeng@***,https:/***/.Education:2003-2007 B.s.,Light Industry engineering and National Economy Management,sichuan university.2007-2013 Ph.D.,Physical {4.,Dalian Institute of chemical Physics,Chinese Academy of sciences(supervisor:*** Bao and *** Pan).

关键词： Dalian Economy Associate

Electrochemical behaviors of Bi (Ⅲ) in dimethylsulfoxide

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Rare Metals 2003年第2期22卷 121-124页

作者： LI Gaoren, TONG Yexiang, and LIU Guankunschool of chemistry and chemical engineering, Zhongshan university, Guangzhou 510275,{4. (Received 2002-02-28) school of chemistry and chemical engineering Zhongshands University Guangzhou 510275

Cyclic voltammetry, chronoamperometry and chronopotentiometry were used toinvestigate the electrochemical behaviors of Bi(III) in Bi(NO_3)_3-LiClO_4.DMsO (dimethylsulfoxide)system on Pt and Cu electrodes. Experimental results indicated that the electroreducation of Bi(III)to Bi(0) was irreversible on Pt and Cu electrodes. The diffusion coefficient and electron transfercoefficient of Bi(III) in 0.01 mol.L^(-1) Bi(NO_3)_3-0.l mol.L^(-1) LiClO_4.DMsO system at 303 Kwere 1.75 X 10^(-6) cm^2.s^1 and 0.14. respectively.

关键词： electrochemistry diffusion coefficient electrochemical behaviors DMsO(dimethylsulfoxide)