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Mechanical and Galvano-chemistry Property Variation within Dissimilar Metal Weld between 1Cr18Ni9Ti and 1Cr13 Stainless Steel

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Journal of Materials science & technology 2010年第5期26卷 477-480页

作者： Yongtao Zhao ,Junhui Dong,Yonglin Ma,Liping Zhao and Xiaobing Pei Material and Metallurgy engineering school,university of science and technology inner mongolia,baotou 014010,china [a] Material and Metallurgy engineering school university of science and technology inner mongolia baotou 014010 china

The purpose of this study is to discuss the microstructure and properties variation of the weld metal in the dissimilar stainless steels during the argon tungsten-arc welding *** of the existence of different materials and chemistry variation within welds,properties,such as tensile and fracture properties and so on,are expected to show spatial *** the study,microstructures were observed by optical and electron *** appearance and uniform structure and typical dendrite structure were observed in welding *** micro-hardness tester and electronic universal stretcher were used to measure the mechanical properties of the weldments and base *** heat affected zone（HAZ） near 1Cr13 hardness is up to peak value of 1150 HV,the strength of weldments is nearly same as austenite stainless *** addition,through seawater immersion test,polarization curves and AC impedance spectroscopy of the weldments and base metals are *** was found that corrosion resistance at welding joint lies between 1C13 and 1Cr18Ni9Ti.

关键词： 1Cr13,1Cr18Ni9Ti Welding joint Mechanical and galvano-chemistry property

Influence of steric and intramolecular inductive effects on the variable trends in R-X (R=Alkyl) bond dissociation energy

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science china chemistry 2009年第7期52卷 943-951页

作者： CAO ChenZhong school of chemistry and chemical engineering, Hunan university of science and technology, Xiangtan 411201, china school of chemistry and chemical engineering Hunan University of Science and Technology Xiangtan 411201 China

The question "why are the variation trends of R-X bond dissociation energy different?" is answered. The R-X bond dissociation energy (BDE) may be influenced by three main factors: the C-X intrinsic bond energy, the 1,3 geminal repulsion, and the intramolecular charge-induced dipole. In the presence of atom X, the variation trend of BDE in R-X (R= Me, Et, i-Pr, t-Bu) is dominated by two factors, the 1,3 geminal repulsion and the intramolecular charge-induced dipole. The former decreases the R-X BDE, and the latter either increases or decreases the R-X BDE. For the series of R-X with the R-C bond (such as R-Me, R-CH == CH2, R-C≡CH, and R-CN), the 1,3 geminal repulsion decreases the R-X BDE, and the variation trends of R-C BDE decrease from Me to t-Bu. As regards the series of R-X (such as R-H, R-BH2, and R-SiH2) in which the electronegativity of atom X is smaller than that of the carbon atom, the above two factors decrease the R-X BDE, and the variation trends of the R-X BDE decrease from Me to t-Bu. As to the series of R-X (such as R-F, R-OH, R-Cl, R-Br, R-I, and R-NH2) in which the electronegativity of atom X is larger than that of the carbon atom, the 1,3 geminal repulsion decreases the R-X BDE, while the intramolecular charge-induced dipole increases the R-X BDE. In this case, the variation trends of R-X BDE depend on the competition of the two factors. As a result, some of them (e. g., R-F, R-OH) increase from Me to t-Bu, some (e. g., R-I) decrease from Me to t-Bu, and some (e. g., R-Br) change very little.

关键词： bond dissociation energy charge-induced dipole geminal repulsion ionic configuration

Synthesis of a novel centipede-like copolymer of styrene and methyl methacrylate

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science china chemistry 2007年第2期50卷 253-257页

作者： LI AiXiang1 & LU ZaiJun2 1 school of Material science and engineering,Shandong university of technology,Zibo 255049,china 2 school of chemistry and chemical engineering,Shandong university,Jinan 250100,china 1. school of Material science and engineering Shandong University of Technology Zibo 255049 China 2. school of chemistry and chemical engineering Shandong University Jinan 250100 China

A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(PS-PS-PMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATRP) . The synthetic approach involves the coupling reaction of polystyrene(PS) backbone bearing 1,1-diphenylethene(DPE) pendant groups,produced by ATRP and Wittig reaction,with living polystyryllithium(PSLi) ,and subsequent polymerization of the resulting 1,1-diphenylmethyl anions with methy methacrylate. The centipede-like copolymer was characterized by 1H NMR,IR,SEC,SLS,and DSC measurements.

关键词： architecture atom transfer radical polymerization centipede-like copolymer coupling reaction living anionic polymerization

Novel nanoporous binary Ag-Ni electrocatalysts for hydrazine oxidation

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Rare Metals 2010年第1期29卷 26-31页

作者： YI Qingfeng, LI Lei, YU Wenqiang, LIU Xiaoping, ZHOU Zhihua, and NIE Huidong school of chemistry and chemical engineering, Hunan university of science and technology, Xiangtan 411201, china school of chemistry and chemical engineering Hunan University of Science and Technology

From an aqueous mixture of Ag（I）-EDTA complex and Ni（II） nitrate, silver and nickel particles were co-deposited on the surface of titanium substrates by the hydrothermal method using hydrazine hydrate as a reduction agent. The prepared titanium-supported nano-scale Ag and Ag-Ni particles （nano Ag/Ti, nano Ag86Ni14/Ti, nano Ag77Ni23/Ti, and nano Ag74Ni26/Ti） exhibit nanoporous 3D network textures. Their electrocatalytic activity towards hydrazine oxidation in alkaline solutions was evaluated by cyclic voltammetry and chronoamperometry. The results show that the four samples present a low onset potential of ca. -0.60 V vs. SCE and considerably high and stable anodic current densities for hydrazine oxidation. Among them, the nano Ag86Ni14/Ti electrode exhibits the highest anodic current density towards hydrazine oxidation, showing an increment of electro-active sites on the nano Ag86Ni14/Ti due to the addition of Ni to Ag particles.

关键词： electrocatalyst silver hydrazine oxidation fuel cell

Kinetic theory of self-condensing vinyl polymerization

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science china chemistry 2010年第12期53卷 2429-2439页

作者： ZHOU ZhiPing 1 & YAN DeYue 2 1 school of Materials science and engineering,Jiangsu university,Zhenjiang 212013,china 2 school of chemistry and chemical engineering,Shanghai Jiao Tong university,Shanghai 200240,china 1. school of Materials science and engineering Jiangsu University Zhenjiang 212013 China2. School of Chemistry and Chemical Engineering Shanghai Jiao Tong University Shanghai 200240 China

This review introduces the kinetic theory of self-condensing vinyl polymerization (SCVP),including the SCVP of AB inimers,the SCVP with non-equal reactivity between A and B groups,the SCVP in the presence of a small amount of multifunctional initiators,also the SCVP of both inimers and *** analytical expressions of various molecular parameters for the resulting hyperbranched polymers,such as the molecular size distribution function,the average molecular weight,the polydispersity index and the degree of branching,are reviewed systematically.

关键词： kinetic theory self-condensing vinyl polymerization (SCVP) hyperbranched polymers

Size effect of fullerene cages and encaged clusters in M3N@C2n

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science china chemistry 2009年第5期52卷 584-589页

作者： GAN LiHua school of chemistry and chemical engineering, Southwest university, Chongqing 400715, china school of chemistry and chemical engineering Southwest University Chongqing 400715 China

Based on the calculated findings that the sizes of encaged clusters determine the structures and the stability of C80-based trimetallic nitride fullerenes (TNFs), more extensive density functional theory calculations were performed on M3N@C68, M3N@C78 and M3N@C80 (M=Sc, Y and La). The calculated results demonstrated that the structures and stability undergo a transition with the increasing of the sizes of the cages and clusters. Sc3N is planar inside the three considered cages, Y3N is slightly pyramidal inside C68-6140 and C78-5 and planar inside I h C80-7, however, La3N is pyramidal inside all the three cages. Those cages with pyramidal clusters inside deformed considerably, compared with their parent cages. In these cases, the bonding of metallic atoms toward the cages does not play an impor-tant role, and the encaged cluster tends to be located inside the cages with the largest M-M and M-C distances so that the strain energy can be released mostly. These calculations revealed the size effect of fullerene cages and encaged clusters, and can explain the position priority of M3N inside fullerene cages and the differences in yield of M3N@C2n.

关键词： trimetallic nitride fullerenes (TNFs) density functional theory (DFT) size effect stability

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 400715, china 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

Biological decomposition of Na_2S_2O_3 into sulfur by a newly isolated facultative thermophilic alkaline desulphuricant strain

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science china chemistry 2009年第2期52卷 226-230页

作者： ZHANG JianBin1,ZHANG Tong2,MA Kai2,ZHANG PengYan2,LI Qiang2 & WEI XiongHui1 1 Department of Applied chemistry,College of chemistry & Molecular engineering,Peking university,Beijing 100190,china 2 College of chemical engineering,inner mongolia university of technology,Huhhot 010051,china 1. Department of Applied chemistry College of Chemistry & Molecular Engineering Peking University Beijing 100190 China 2. College of chemical engineering Inner Mongolia University of Technology Huhhot 010051 China

A facultative thermophilic alkaline desulphuricant strain named GDJ-3 was isolated from neutral soils,enriched on sulfur synthetic medium,and detected in previous *** and chemotax-onomic analyses and 16s RNA gene sequencing showed that the strain was in good agreement with Alpha proteobacterium sp.(97%) and ochrobactrum sp.(98%).The regenerative processes of the solu-tion containing sulfur compounds(SCS) from the strain through an orthogonal test were investigated to get the optimum regenerative *** results showed that regenerative temperature,air flow,and stirring speed of the agitator were the main three variables influencing the regenerative processes of the *** optimum regenerative efficiency of the SCS from the strain was obtained when tem-perature,air flow,and stirring speed of the agitator were 318.2 K,3.0 L/min,and zero r/min,*** this condition,when the cell concentration of the strain was adjusted to 107/mL,the concentra-tions of Na2S2O3 and Na2S in the SCS decreased from 112.68 g/L to 96.88 g/L and from 0.87 g/L to 0.11 g/L in 9.5 ***,XRD spectrum shows that sulfur was formed in the regeneration *** results suggest that the strain has potential application to the regeneration of the industrial so-lution containing sulfur compounds.

关键词： bio-desulfurization thermophiles optimization biocomposition orthogonal test

Boron rings containing planar octa- and enneacoordinate cobalt, iron and nickel metal elements

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science china chemistry 2008年第7期51卷 607-613页

作者： LUO Qiong school of chemistry and chemical engineering, Central South university, Changsha 410083, china school of chemistry and chemical engineering Central South UniversityChangsha 410083China

For a series of boron rings with planar hyper-coordinate 8th group transition metal atoms, singlet 1FeB8-2, multiplet kFeB9n (n = -1, k = 1; n = 0, k = 2), singlet 1CoB8n(n = -1, +1, +3), multiplet kCoB9n (n = +1, k = 2; n = 0, k = 1) and singlet 1NiB9+, the geometry structures have been optimized to be local minima on corresponding potential hyper-surfaces. The electron structures are discussed by orbital analysis and the aromaticity is predicted by nucleus-independent chemical shifts calculation at both the B3LYP/6-311+G* and BP86/6-311+G* levels of theory, respectively. The results suggest that all these structures with high symmetry planar geometries are stable and have aromatic properties with six π valence electrons.

关键词： planar hyper-coordinate transition metal DFT