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The Application of SCC-DV-X_a Computational Method of quantum Chemistry in Cement Chemistry

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Journal of Wuhan University of Technology(Materials sci.nce) 2001年第3期16卷 6-11页

作者：王志 dept. of Materials sci. and eng. Jinan University Shandong 250022 China

It has been explored why quantum chemistry is applied to the research field of cement chemistry. The fundamental theory of SCC-DV-Xα computational method of quantum chemistry is synopsized. The results obtained by computational quantum chemistry method in recent years of valence-bond structures and hydration activity of some cement clinker minerals, mechanical streng.h and stabilization, of some hydrates are summarized and evaluated. Finally the prospects of the future application of quantum chemistry to cement chemistry are depicted.

关键词： quantum chemistry cement calculated results hydratian property

Wettability and Bonding between Ni and Ti(C,N)with Multiple Carbide Additions

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Journal of Materials sci.nce & Technology 2005年第1期21卷 53-59页

作者： Ning LIU, Minghai CHEN, Yudong XU, Jie ZHOU and Min SHIDepartment of Materials sci.nce and eng.neering, Hefei University of Technology, Hefei 230009, ChinaProf., Ph.D. dept. of Mat. sci. and eng. Hefei Univ. of Technol. Hefei 230009 China

The wettability and bonding in Ni/Ti(C, N) systems with multiple carbide additions were studied by sessile drop technique and vacuum brazing technique, respectively. The phase characterizations of substrates and fracture surfaces were conducted by XRD. The microstructures at metal/ceramic interfaces and fracture surfaces were observed via SEM in back scattered mode and second electron mode, respectively. Furthermore, an X-ray energy-dispersive spectrometer (EDS) attached to SEM was used to study the elements diffusion in interfacial regions. The results reveal that diffusion and dissolution mechanism controlled reactive wetting takes place in the system in high temperature wetting. Results also show that the contact angles decrease with multiple carbide additions, and the effect of multiple carbide additions is stronger than that of single additions. The contact angle reaches the lowest value in the lowest TiC content case. The enhancement of the wettability is due to alloying procedure during high tempe

关键词： Interfaces Diffusion Ti(C, N)-based cermets Wettability Bonding

Fast Pyrolysis of Biomass in a Spout-fluidized Bed Reactor ——Analysis of Composition and Combustion Characteristics of Liquid Product from Biomass

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过程工程学报 2006年第2期6卷 192-196页

作者：陈明强王君王新运张学才张素平任铮伟颜涌捷 dept. Chemical eng.neering Anhui University of Science and Technology Huainan dept. Chem. eng. energy Recourses East China Univ. Sci. & Technol.

In order to gain insight into the fast pyrolysis mechanism of biomass and the relationship between bio-oil composition and pyrolysis reaction conditions, to assess the possibility for the raw bio-oil to be used as fuel, and to evaluate the concept of spout-fluidized bed reactor as the reactor for fast pyrolysis of biomass to prepare fuel oil, the composition and combustion characteristics of bio-oil prepared in a spout-fluidized bed reactor with a designed maximum capacity 5 kg/h of sawdust as feeding material, were investigated by GC-MS and thermogravimetry. 14 aromatic series chemicals were identified. The thermogravimetric analysis indicated that the bio-oil was liable to combustion, the combustion temperature increased with the heating rate, and only minute ash was generated when it burned. The kinetics of the combustion reaction was studied and the kinetic parameters were calculated by both Ozawa-Flynn-Wall and Popsecu methods. The results agree well with each other. The most probable combustion mechanism functions determined by Popescu method are f(α)=k(1-α)2(400～406 ℃), f(α)=1/2k(1-α)3 (406～416 ℃) and f( α)=2k(1-α)3/2 (416～430 ℃) respectively.

关键词：生物量热解流动床液体产物燃烧特征

Quantitative calculation for the dissipated energy of fault rock burst based on gradient-dependent plasticity

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Journal of University of sci.nce and Technology Beijing 2004年第3期11卷 197-201页

作者： Xuebin Wang Shuhong Dai Long Hai Department of Mechanics and eng.neering sci.nces, Liaoning Technical University, Fuxin 123000, China dept. of Mech. and eng. sci. Liaoning Tech. Univ. Fuxin 123000 China

The capacity of energy absorption by fault bands after rock burst wascalculated quantitatively according to shear stress-shear deformation curves considering theinteractions and interplaying among microstructures due to the heterogeneity of strain softeningrock materials. The post-peak stiffness of rock specimens subjected to direct shear was derivedstrictly based on gradient-dependent plasticity, which can not be obtained from the classicalelastoplastic theory. Analytical solutions for the dissipated energy of rock burst were proposedwhether the slope of the post-peak shear stress-shear deformation curve is positive or not. Theanalytical solutions show that shear stress level, confining pressure, shear streng.h, brittleness,strain rate and heterogeneity of rock materials have important influence on the dissipated *** larger value of the dissipated energy means that the capacity of energy dissipation in the formof shear bands is superior and a lower magnitude of rock burst is expected under the condition ofthe same work done by external shear force. The possibility of rock burst is reduced for a lowersoftening modulus or a larger thickness of shear bands.

关键词： rock burst heterogeneity dissipated energy plastic strain gradient post-peak stiffness characteristic leng.h fault band strain softefiing

Study on Co-Permeation of Solid Rare Earth, Boron and Vanadium

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Journal of Rare Earths 2001年第2期19卷 149-152页

作者：陶小克董桂霞彭日升孙永昌 dept. of Mat. sci. and eng. Tianjin Inst. of Technol. Tianjin 300191 China

The effect of rare earth compound of CeCl3 on the kinetic process, composition, microstructure and mechanical properties of co-permeating of solid powder boron-vanadium (B-V) was investigated. The results indicate that the addition of CeCl3 to permeating agent not only has obviously catalytic effect on permeating rate, which increases by more than 40%, hut also greatly improves the hardness and abrasion resistant of the permeating layer owing to the formation of new phase of CeFe2 after Ce permeates into the layer of the part as an alloying ingredient. It is believed that rare earth elements accelerate the permeating rate of B and V by increasing the potentials of B and V of the agent, activating the surface of the workpiece, and decreasing the activation energy of diffusion of the B and V atoms.

关键词： rare earths boron potential vanadium potential co-permeation of rare earth boron and vanadium

ANISOTROPY OF (1×1)-SURFACE FREE ENERGIES OF CRYSTALS

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Acta Metallurgica Sinica(eng.ish Letters) 2001年第6期14卷 485-492页

作者： Z.M. Yu (Department of Materials sci.nce and eng.neering, Central South University, Changsha 410083, China) A. Flodstrom (Royal Institute of Technology, KTH, Office of the President, Valhallavdgen 79, S-100 44 Stockholm, Sweden) dept. of Mat. sci. and eng. Central South Univ. Changsha 410083 China

The surface free energy (SFE) of (1× 1)-surfaces of crystals, without reconstructionand adsorption, is calculated using a bond-broken mode. In the mode, the potentialenergy of the crystals is treated as a sum of the energies of the bonds connectingpair-wise atoms (u-bonds). The SFE is calculated based on the bond energy and thearea density of dangling bonds which depends on the structure of the surface. Theresults provide a general expression for the SFE in terms of the bond energy (E)and the bond leng.h (do) of the crystal and Miller indices hkl. The anisotropy ofthe SFE is therefore completely determined with the expression. As the examples,considering the nearest-neighboring bonding, the SFEs of sc, fcc, bcc and cth (cubictetrahedral) crystals are discussed, respectively. Wulff plots of bcc and fcc crystalsare then obtained. The equilibrium forms (EFs) of these crystals ave consequentlygot from their Wulff plots, respectively. It is found that the EFs of bcc and fcc arerespectively the rhombic dodecahedron and the truncated-octahedron that are their firstBrillouin zones, respectively.

关键词： surface free energy crystal geometrical thermodynamics

An approach to the estimation of solute hydrogen-bond donor acidity

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Chinese sci.nce Bulletin 1996年第9期41卷 732-735页

作者：冯流韩朔睽王连生 dept. of Environ. sci. and Eng. Nanjing University Nanjing 210093 China

Hydrogen-bond donor acidity α~H, an important parameter for the linear solvation energyrelationship (LSER) theory, can be experimentally measured or estimated indirectly bysome methods. But it is time-consuming and difficult to measure this parameter. Inthis note, a new approach is presented to estimate it on the basis of the LSER theory.

关键词： sotvatochromic parameter partition coefficient linear solvation energy relationship.

Crystallization Kinetics of NiTi Films with Different Ni Contents

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Journal of Materials sci.nce & Technology 2001年第4期17卷 421-424页

作者： Xunyong JIANG, Huibin XU and Sheng.ai GONG Department of Materials sci.nce and eng.neering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China dept. of Mat. sci. and eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

Three kinds of NiTi films with different Ni contents were prepared by DC magnetron sputtering. The crystallization kinetics of amorphous films was determined by using non-isothermal single- scan techniques. The results show that the activation energy of crystallization of Ni-rich NiTi film(Ni 51.10 at. pct, Ti 48.90 at. pct) is 715 kJ/mol; while that of Ti-rich films are similar: one is 445 kJ/mol (Ni 46.74 at. pct. Ti 53.26 at. pct), the other is 418 kJ/mol (Ni 43.21 at. pct, Ti 56.7g at. pct), which i5 lower than Ni-rich film. The Avrami parameter n of different films are 0.92 and 0.74 for Ni-rich film and Ti-rich films, respectively. The difference of kinetic parameters for NiTi films with various Ni contents implies that the crystallization behaviors of these films are distinct, which is confirmed by the calculated isothermal kinetics at different temperatures. The thorough research on this phenomenon is in progress.

关键词： NiTi Crystallization Kinetics of NiTi Films with Different Ni Contents

A New hcp Phase Formed in the Ni-Nb System during Ion-beam-assisted Deposition

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Journal of Materials sci.nce & Technology 2004年第5期20卷 577-579页

作者： Bin ZHAO, Kuiwei Geng. Fei Zeng.and Feng.PANLaboratory of Advanced Materials, Department of Materials sci.nce and eng.neering, Tsinghua University, Beijing 100084, China Lab. of Adv. Mat. Dept. of Mat. Sci. and Eng. Tsinghua Univ. Beijing 100084 China

The Ni80Nb20 films were prepared by ion beam assisted deposition (IBAD) with various Ar+ ion energies. A phase evolution of fcc→amorphous→Ni+Nb→Ni+hcp was observed with the increasing of ion beam energy from 2 keV to 8 keV. When bombarded by Ar+ ions of 8 keV during deposition, a new crystalline phase with hcp structure was obtained, of which the lattice parameters are a=0.286 nm and c=0.483 nm, different from those of the similar A3B-type hcp phase previously reported. The experimental results were discussed in terms of thermodynamics and restricted kinetic conditions in the far-from-equilibrium process of IBAD. The formation of hep phase may also be related to the valence electron effect.

关键词： Hcp phase Ni-Nb Ion beam assisted deposition Thermodynamics Valence electron effect