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Quantitative Evaluation for Drawability of Sheet Metal

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Journal of Materials Science & technology 2005年第5期21卷 763-766页

作者： Zhiqing XIONG and Xuemei YANGdepartment of Mechanical engineering,{2., nanjing 210013, china department of Mechanical engineering Nanjing Institute of Technology Nanjing 210013 China

The theoretical evaluating method is given for the drawability of the sheet with normal anisotropy. The general solution on the cracking load of deep-drawing is deduced, which is based on three kinds of hardening curve of materials most in use. The distributions of stress and strain in the deformed region and the drawing force are obtained by the numerical method. The limiting drawing ratio is calculated through computer-aided simulating test. The experiments of deep-drawing to four kinds of sheet metals express that the relative errors between the predictive and the experimental results about the cracking load and the limiting drawing ratio are within 5%. The drawability of common sheet metals can be quantitatively evaluated in precise terms by means of the theory and the method advanced in this paper.

关键词： Sheet forming Deep-drawing Formability Drawability

Game model of safety monitoring for arch dam deformation

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Science china(Technological Sciences) 2008年第S2期51卷 76-81页

作者： SU HuaiZhi1,2.WU ZhongRu1,2.GU YanChang1,2.HU Jiang1 & WEN ZhiPing3 1 College of Water Conservancy and Hydropower engineering,Hohai University,{2. 2.0098,china 2.National engineering Research Center of Water Resources Efficient Utilization and engineering Safety,{2. 2.0098,china 3 department of Computer engineering,{2. institute of {12.,{2. 210013,china College of Water Conservancy and Hydropower engineering Hohai University Nanjing 210098 China National engineering Research Center of Water Resources Efficient Utilization and engineering Safety Nanjing 210098 China department of Computer engineering Nanjing Institute of Technology Nanjing 210013 China

Arch dam deformation is comprehensively affected by water pressure,temperature,dam's structural behavior and material properties as well as other *** them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam's structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance ***,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of *** the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

关键词： arch dam deformation monitoring model flexibility coefficient game theory

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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 {2., nanjing 2.0094, china 2. institute of Chemical Materials, china Academy of engineering Physics, Mianyang 62.900, china 1. department of Chemistry Nanjing University of Science and Technology 210094 Nanjing China 2. institute of Chemical Materials China Academy of Engineering Physics 621900 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).

Study on design pressure of in-service welding pipes

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Science china(Technological Sciences) 2006年第4期49卷 434-444页

作者： XUE Xiaolong1, ZHU Jiagui2.& SANG Zhifu1 1. College of Mechanical and power engineering, {2. University of technology, {2. 2.0009, china 2. {2. Yangzi Petrochemical Maintenance and Installation Co. Ltd., {2. 2.0048, china 1. College of Mechanical and power engineering Nanjing University of Technology Nanjing 210009 China 2. nanjing Yangzi Petrochemical Maintenance and Installation Co. Ltd. Nanjing 210048 China

A method of predicting design pressure and burn-through of in-service welding pipes was established. Temperature distributions of in-service welding under variable parameters were simulated by FEM. The effect of flowing of internal media was regarded as forced convection. Based on the numerical results, design pressure of the pipe can be obtained and burn-through can be predicted. It can be concluded that the design pressure decreases with the increasing of heat input. RSF and design pressure of the pipe increase with the increasing of flow rate. There is a range in which the increase changes greatly. For in-service welding, the range should be considered adequately to determine operating condition optimally. RSF increases with the increasing of pipe wall thickness. While the thickness increases to an extent, RSF shows little increase. Accord- ing to the curves of design pressure versus different parameters, safe working pressure can be achieved.

关键词： in-service welding, heat input, flow rate, pipe wall thickness, design pressure.

Structure and Pozzolanic Activity of Calcined Coal Gangue during the Process of Mechanical Activation

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Journal of Wuhan University of technology(Materials Science) 2009年第2期24卷 326-329页

作者：郭伟 department of Material engineering Yancheng Institute of Technology institute of Material Science and engineering Nanjing University of Technology

On the basis of analyzing coal gangue＇s chemical and mineral compositions, the structure change of coal gangue during the mechanical activation was investigated by XRD, FTIR, NMR, and the mechanical strength of the cement doped coal gangue with various specific surface area was tested. The experimental results indicate that, the lattice structure of metakaolin in coal gangue samples calcined at 700 ℃ disorganizes gradually and becomes disordered, and the lattice structure of α-quartz is distorted slightly. The pozzolanic activity of the coal gangue increases obviously with its structural disorganization.

关键词： coal gangue mechanical activation structure NMR tetrahedron

Early Hydration of Composite Cement with Thermal Activated Coal Gangue

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Journal of Wuhan University of technology(Materials Science) 2010年第1期25卷 162-166页

作者：郭伟 department of Material engineering Yancheng Institute of Technology institute of Material Science and engineering Nanjing University of Technology

Composite cement samples were prepared by mixing clinker, gypsum with burnt coal gangues which was calcined at various temperatures. The mechanical strength and Ca（OH）2.content in the cement paste were tested, and the paste composition and microstructure were analyzed by thermogravimetry-differential thermal analysis （TG-DSC）, X-ray diffraction（XRD）, scanning electronic microscopy （SEM） and pore structure analysis. Results demonstrate that the thermal activated coal gangue could accelerate the early hydration of cement clinker obviously, which promotes the gangue hydration itself. The early hydrated products of the cement are C-S-H gel, Ca（OH）2.and AFt. The cement with 30% （in mass） the gangue exhibits higher mechanical strength, and among all the cement samples the one with the gangue burnt at 700 ℃ displays the highest hydration rate, mechanical strength, the most gel pores and the lowest total porosity.

关键词： blended cement hydration microstructure hydration product

Microstructure and Properties of Mg-12.d-3Y-0.5Zr Alloys Processed by ECAP and Extrusion

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Journal of Wuhan University of technology(Materials Science) 2011年第6期26卷 1128-1132页

作者：朱荣 department of Materials Science and engineering Nanjing University of Science and Technology

Equal channel angular pressing （ECAP） processing and conventional extrusion （Ex） were applied to the Mg-12.d-3Y-0.5Zr （wt%） magnesium alloy in order to evaluate the potential improvement in the mechanical properties. The ECAP experiment was conducted at 380 ℃ in a die having an included angle of 90° between two channels by the Bc route with the billet rotated by 90° about its longitudinal axis. Subsequently, some billets were processed by conventional extrusion at 300 ℃. The microstructures were examined by X-ray diffraction （XRD）, optical microscopy and transmission electron microscopy （TEM）. The experimental results indicate that the grain size is refined effectively, but the basal planes are highly inclined （about 40o） from the extrusion axis introduced by ECAP, which impairs the grain boundary strengthening effect. The conventional extrusion, following the ECAP, can modify the grains in hard orientation. Based on grain boundary strengthening due to ECAP and texture strengthening due to Ex, the strength is improved effectively. The enhanced activity of the non-basal slips, due to the refined grains and the reduction in c/a ratio, is responsible for good ductility and high strain hardening rate in samples obtained by the two-step process.

关键词： magnesium alloy equal channel angular pressing thermomechanical processing texture

Low-complexity distributed differential spacetime coding scheme for amplify-and-forward cooperative networks

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Science in china(Series F) 2009年第8期52卷 1418-1427页

作者： YU XiangBin1,2. BI GuangGuo3 & XU WeiYe4 1 College of Information Science and technology, nanjing University of Aeronautics and Astronautics, nanjing 2.0016, china 2.department of Electronic engineering, City University of Hong Kong, Hong Kong, china 3 National Mobile Communications Research Laboratory, Southeast University, nanjing 2.0096, china 4 department of Communication engineering, nanjing institute of technology, nanjing 2.1167, china College of Information Science and technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China department of Electronic engineering City University of Hong Kong Hong Kong China National Mobile Communications Research Laboratory Southeast University Nanjing 210096 China department of Communication engineering Nanjing Institute of Technology Nanjing 211167 China

By introducing a space-time coding scheme based on amicable orthogonality, we develop a distributed differential space-time coding scheme with the amplify-and-forward （AF） method for wireless cooperative networks. The scheme requires no knowledge of the channel state information at both transmitters and receivers, and effectively decreases the realization complexity due to no channel estimation. Moreover, it has lower decoding complexity and higher coding advantage than the existing scheme, thus avoiding the shortcoming of exponential decoding complexity of some existing schemes. According to the pairwise error probability （PEP） analysis of the system, the power allocations of source and relay terminals are jointly optimized, and as a result, the PEP is minimized, which will provide a helpful guideline for system design. Numerical calculation and simulation results show that the developed scheme is superior to the existing scheme. Moreover, the scheme with optimal power allocation yields obvious performance improvement over that with equal power allocation.

关键词： differential space-time coding cooperative communication amplify-and-forward method power allocation

A whisker-like carbon composite for the immobilization of laccase and its bioelectrochemistry

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Science china Chemistry 2010年第6期53卷 1332-1336页

作者： MA GuoXian1,2.ZHONG QingDong2.& LU TianHong3 1department of Chemical engineering,Shanghai {2. of technology,Shanghai 2.02.3,china 2.chool of Materials Science and engineering,Shanghai University,Shanghai 2.0072.china 3department of Chemistry,nanjing Normal University,nanjing 2.0097,china 1. department of Chemical engineering Shanghai Institute of Technology Shanghai 200233 China2. School of Materials Science and Engineering Shanghai University Shanghai 200072 China3. Department of Chemistry Nanjing Normal University Nanjing 210097 China

A novel mesoporous carbon/whisker-like carbon (MCWC) composite was used for the immobilization of laccase (Lac) and its bioelectrochemical behaviors were *** was confirmed by XPS that Lac was strongly adsorbed on the surface of the MCWC *** cyclic voltammetric results showed that the immobilized Lac underwent a direct quasi-reversible electrochemical *** value of the electron transfer rate constant ks was estimated to be 0.770 s-1,indicating a reasonably fast electron transfer between the immobilized Lac and the underlying *** surface concentration (I-) of Lac was estimated to be 2.730 × 10-12.mol/*** experimental results showed that the immobilized Lac displayed an appreciable electrocatalytic activity to the electrochemical reduction of *** properties could be attributed to the particular structure of loosely packed nanometer-scale carbon whiskers and the existence of a large amount of oxygen-containing *** immo- bilization method and the novel carrier (MCWC) may find new applications in fabricating the biocatalysts for biofuel cells.

关键词： laccase whisker-like carbon composite direct electrochemical reaction oxygen bioelectrochemistry