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稀有金属材料与工程 2012年第S1期41卷 344-349页

作者： Guo Chun1,2.Chen Jianmin1,Zhou Jiansong1,Zhao Jierong1,2.Wang Lingqian1,2.Yu Youjun1,2.Zhou Huidi 1 1 Lanzhou Institute of Chemical Physics,Chinese Academy of sciences,Lanzhou 730000,china 2.Graduate University of Chinese Academy of sciences,Beijing 100039,china Chinese Acad Sci Lanzhou Inst Chem Phys Lanzhou 730000 Peoples R China Chinese Acad Sci Grad Univ Beijing 100039 Peoples R China

TiB2.TiB/TiNx(x=1,0.3)/Ti composite coating was prepared on pure Ti by laser surface alloying by using powders of boron as starting *** composite coating was examined by X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM)and scanning electron microscopy(SEM).The friction and wear properties of the composite coating were examined using a pin-on-disk tester under dry sliding wear *** results showed that the top surface of the composite coating was mainly composed of TiB2.TiB,TiN0.3,TiN and Ti phases,while the interface of the composite coating was composed of TiB and Ti *** composite coating showed sticklike structure near the top surface,and dendrites structure near the *** friction and wear test showed that the composite coating had better wear resistance than pure Ti due to their higher microhardness than that of pure Ti substrate.

关键词： pure Ti laser surface alloying TiB2 composite coating friction and wear property

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Table Operation Method for Optimal Spanning Tree Problem

2.09中国控制与决策会议

作者： Lu Nannan~1,Qian Jiansheng~(1,2.,Zhao Zhikai~2.Zhang Liqin~1,Lu Jin~1 1.school of information and Electrical {2.,china University of Mining and Technology,Xuzhou,Jiangsu,2.1008 china 2.school of Computer science and Technology,china University of Mining and Technology,Xuzhou,Jiangsu,2.1008 china

＜正＞Coal or Rock Electromagnetic Emission is a new perspective of predicting rock burst,but most present researches have been investigated into physical *** paper analyzes coal or rock electromagnetic emission （Coal or Rock EME） with self-similarity by rescaled range method from fractal characteristic and validates the feasibility and applicability of prediction model based on chaos *** to EME signal from two sides of Railway Lane and Transportation Lane from Dongtan coal mine respectively,we compute hurst exponent and fractal dimension D, and verify hurst exponent by the standard of *** experiments in this domain show that the signal has significant statistical ***,we conclude that Coal or Rock EME has a favorable fractal ***, we can utilize non-linear method to make prediction further.

关键词： Coal or Rock Electromagnetic Emission Fractal Self-similarity R/S Method Hurst Exponent

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Journal of Systems engineering and Electronics 1998年第4期9卷 31-40页

作者： Feng Junwen(school of Economics and Management, nanjing University of {2. and Technology,2.0094, P. R. china) school of Economics and Management Nanjing University of Science and Technology 210094 P. R. China

As far as the weight digraph is considered, based on the table instead of the weightdigraph, an optimal spanning tree method called the Table Operations Method (TOM) is *** the optimality is proved and a numerical exa... 详细信息

关键词： Optimal spanning tree problem Digraph Rooted tree Table representation

Effect of Cooling Rate on Morphology and Oxygen Permeability of Polypropylene

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 219-223页

作者： Wei Tian Raymond T. Whodhams(Material science and engineering {2., University of science and Technology Beijing, Beijing 100083, china)(Department of Chemical engineering and Applied Chemistry University of Toronto, Toronto M5S IA4, Canada) Material science and engineering {2. University of Science and Technology Beijing Beijing 100083 China Department of Chemical engineering and Applied Chemistry University of Toronto Toronto Ont. M5S IA4 Canada

The influence of different cooling rates on the morphology and oxygen permeabilityr of polypropylene containing ferrocene has been investigated. The spherulitic crystalline size and structure, which can affect the oxygen permeability are dependent upon the heating temperature, annealing time and cooling rate. The modulus of the composite was measured b}' dynamic mechanical analysis.

关键词： polypropylene oxygen permeability cooling rate

Quenched moderate deviations principle for random walk in random environment

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science china Mathematics 2010年第8期53卷 1947-1956页

作者： HONG WenMing 1 & WANG HuaMing 1,2.1 Key Laboratory of Mathematics and Complex Systems of Ministry of Education & school of Mathematical sciences,Beijing Normal University,Beijing 100875,{2. 2.Department of Basic Courses,Business College,Beijing Union University,Beijing 10002.,{2. 1. Key Laboratory of Mathematics and Complex Systems of Ministry of Education & school of Mathematical sciences Beijing Normal University Beijing 100875 China2. Department of Basic Courses Business College Beijing Union University Beijing 100025 China

We derive a quenched moderate deviations principle for the one-dimensional nearest random walk in random environment,where the environment is assumed to be stationary and *** approach is based on hitting time decompos... 详细信息

关键词： random walk in random environment moderate deviations principle hitting time

An ant colony algorithm for solving Max-cut problem

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Progress in Natural science:Materials International 2008年第9期18卷 1173-1178页

作者： Lin Gaoa,, Yan Zeng b, Anguo Dong a,c a school of Computer science and Technology, Xidian University, Xi’an 710071, {2. b Computer science Department, Xi’an Institute of Post & Telecommunications, Xi’an 710061, {2. c school of science, Chang’an University, Xi’an 710064, {2. school of Computer science and Technology Xidian University Xi’an 710071 China Computer science Department Xi’an Institute of Post & Telecommunications Xi’an 710061 China school of science Chang’an University Xi’an 710064 China

Max-cut problem is an NP-complete and classical combinatorial optimization problem that has a wide range of applications in dif-ferent domains, such as bioinformatics, network optimization, statistical physics, and very large scale integration *** this paper we investigate the capabilities of the ant colony optimization (ACO) heuristic for solving the Max-cut problem and present an AntCut algo-rithm.A large number of simulation experiments show that the algorithm can solve the Max-cut problem more eficiently and efiectively.

关键词： Ant colony optimization Max-cut problem Algorithm

NEW ACHIEVEMENTS ON THE THEORY AND TECHNOLOGY OF EXPLOSIVE WELDING

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Acta Metallurgica Sinica(English Letters) 2003年第6期16卷 531-537页

作者： C.G. Shi, Y.H. Wang, L.G. Cai and C.H. Zhouengineering Institute of engineering Corps, PLA University of {2. and Technology, nanjing 2.0007, china engineering Institute of engineering Corps PLA University of Science and Technology

There are four new achievements of this work on the theory and technology of explosive welding.(1) It has been found and defined three kinds of bonding interfaces: big wavy, small wavy and micro wavy, and the micro wavy interface is the best. In a cladding plate, it is for the first time to find that the form of interface presents regular distribution.(2. Although the interface has the features of melt, diffusion and pressure welding in the mean time, the seam and 'hole' brought by the melt weaken the bonding strength of interface greatly, and the effect of melt on interface must be eliminated in explosive welding, so explosive welding is not a melt weld. The diffusion welding is a kind of form of pressure welding, and the diffusion is not the reason of the bonding of interface but the result of interface high pressure. So the diffusion welding cannot also explain the bonding mechanism of it. The experiment and theory make clear that explosive welding is a special pressure one.(3) To get good interface of no melt, explosive charge must be selected on the low limit of welding windows. In explosive welding, the drive plate should be treated as the viscous and plastoelastic body, not incompressible fluid. The bending moment under the explosive welding loading must be greater than that under dynamic limit of drive plate. According to the condition, the lower limit of explosive welding is obtained. It is about 2.% less than that obtained by tradition calculation, and suitable for engineering application.(4) It is for the first time to test and study on soil anvil characteristics and change regularity under explosive welding impact loading. Through soil anvil parameter optimization analysis, it is the best for explosive welding with sandy soil of water content 17.00% and density 1.74q/cm3.

关键词： explosive welding bonding interface pressure welding low limit

Lateral buckling of non-trenched high temperature pipelines with pipelay imperfections

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Petroleum science 2010年第1期7卷 123-131页

作者： Zhao Tianfeng Duan Menglan Pan Xiaodong Feng Xianhong Offshore Oil/Gas Research Center China University of Petroleum Beijing 102249 China Offshore Oil engineering Ltd. Tanggu Tianjin 300452 China

An analysis method for the buckling process of a pipe section with a random pipelay imperfection is proposed. Four basic lateral modes, acquired by finite-element （FE） eigenvalue buckling analysis, are combined to provide the needed grid configurations for describing a real pipelay imperfection and an arc-length algorithm is used to analyze the snap-through process of the shell-element-grid model under nonlinear frictional boundary conditions. This paper also presents evaluation methods for the lateral buckling of two types of pipe-in-pipe systems that are used in the offshore oil and gas industry. For evaluating the buckling and postbuckling of compliant pipe-in-pipe systems FE analyses were carried out to judge the occurrence of the system buckling and furthermore to check postbuckling stresses induced in the buckles. The calculated results of the modified Riks algorithm indicate that only when high temperature would not trigger an abrupt short-wavelength buckle and when no yielding has been induced in the unavoidable long-wavelength buckles, the thermal stability and safety of compliant pipe-in-pipe systems can be proved. In the non-compliant pipe-in-pipe systems, firstly small-amplitude buckles of the carrier pipe may occur in the annulus between carrier pipe and casing pipe and the contact forces between the spacers and the casing pipe may drive the buckle of the pipe-in-pipe systems on the seabed. Based on the classical analytical solution of pipe buckling, four potential buckling modes corresponding to finite- element models are developed to evaluate the stability and the postbuckling strength of such pipe-in-pipe systems.

关键词： Lateral buckling postbuckling pipe-in-pipe systems modified Riks method buckling modes

Plankton from Early Cambrian black shale series on the Yangtze Platform, and its influences on lithologies

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Progress in Natural science:Materials International 2003年第10期 57-62页

作者： Andreas BRAUN 1* and CHEN Junyuan 2.1. Institute of Paleontology, University of Bonn, Nussallee 8, D 53115 Bonn, Germany 2. nanjing Institute of Geology and Palaeontology, Chinese Academy of sciences, nanjing 2.0008, china) Institute of Paleontology University of Bonn Nussallee 8 D-53115 Bonn Germany nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China

Black shales, cherts, and associated lithologies in the Early Cambrian of the Yangtze Platform yielded abundant phytoplankton, the earliest well preserved skeletons of zooplankton (radiolarians) and abundant phosphatic ovoid bodies, probably representing fecal pellets, produced by Mesozooplankton grazing on phytoplankton. The oceanic food chain in surface waters is therefore considered to be more complete than known up to now with respect to primary and secondary consumers in the Early Cambrian plankton ecosystem. On the basis of primary sedimentary compositions preserved in phosphorite concretions and chert layers it is shown that biosiliceous sedimentation mixed with organic substance played a significant role within the black shale sequence of the Hetang and Niutitang formations. The resulting lithology corresponds closely in character to the bituminous Alum shale and Lydite sequences of Lower Silurian (Llandoverian) age along northern Gondwana (e.g. Thuringia, Bohemia).

关键词： Black shale Cambrian Plankton Yangtze Platform china.

Heterogeneous reaction of formaldehyde on the surface of TiO_2.particles

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science china Chemistry 2010年第12期53卷 2644-2651页

作者： XU BingYe 1,2.ZHU Tong 1,TANG XiaoYan 1 & SHANG Jing 1 1 State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental sciences and engineering,Peking University,Beijing 100871,{2. 2.Zhejiang Province Environmental Monitoring Center,Hangzhou 310012.{2. 1. State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental sciences and engineering Peking University Beijing 100871 China2. Zhejiang Province Environmental Monitoring Center Hangzhou 310012 China

The heterogeneous reaction of formaldehyde (HCHO) on the surface of titanium dioxide (TiO2. was investigated in situ using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) combined with ion chromatography (IC),X-ray diffraction (XRD),and transmission electron microscopy (TEM).Formate,dioxymethylene,methoxy,and polyoxymethylene were observed in the infrared spectra of TiO2.particles during the *** the surface of TiO2.the adsorbed HCHO was first oxidized to dioxymethylene and further oxidized to *** effects of temperature and ultraviolet radiation (UV) on the reaction products and reactive uptake coefficients were studied,and the results indicate that the reaction rate can be accelerated at increasing temperatures as well as under *** heterogeneous reaction mechanisms of HCHO on the surface of TiO2.in the dark and under UV irradiation are *** measurements show that formate formation on TiO2.is second order in HCHO concentration and the initial reactive uptake coefficients at room temperature calculated with the Brunauer-EmmettTeller specific surface area are (0.5-5) × 10-8 ([HCHO]:1 × 1013-2.× 10 14 molecules/cm3).A linear function relationship exists between the uptake coefficient and the *** apparent activation energy of the reaction was also determined.

关键词： DRIFTS formaldehyde heterogeneous reaction reactive uptake coefficient TiO2