检索结果-南通市图书馆

Computation of the Viscous Hydrodynamic Forces on a KVLCC2 Model Moving Obliquely in Shallow Water

在线全文

学校读者我要写书评

暂无评论

Journal of shanghai jiaotong university(science) 2009年第2期14卷 241-244页

作者：王化明邹早建田喜民 School of Naval Architecture Ocean and Civil EngineeringShanghai Jiaotong University State Key Laboratory of Ocean engineering Shanghai Jiaotong University

The viscous hydrodynamic force and moment on ships moving obliquely in shallow water are important for ship navigation *** the paper,the viscous flow field around a KVLCC2 model moving obliquely in shallow water is simulated and the hydrodynamic drag,lateral force and yaw moment acting on the hull are obtained by a general purpose computational fluid dynamics(CFD) package FLUENT with shear-stress transport(SST) k—ωturbulence *** numerical computation is performed at different drift angels and water *** numerical results are compared with experimental results,and a good agreement is demonstrated.

关键词： oblique motion shallow water viscous flow hydrodynamic forces numerical simulation

Annealing High Resistivity CdZnTe Wafers under Controlled Cd/Zn Partial Pressures

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2004年第6期20卷 703-706页

作者： Wanwan LI, Wenbin SANG, Bin ZHANG, Jiahua MIN and Fang YUSchool of Material science and engineering, Jiading Campus, shanghai university, shanghai 201800, chinaInstitute of Composites Materials, shanghai Jiao Tong university, shanghai 200030, china Sch. of Mat. Sci. and Eng. Shanghai Univ. Shanghai 201800 China Inst. of Composites Mat. Shanghai Jiaotong Univ. Shanghai 200030 China

In order to improve the performances of CdZnTe 7-ray detector, it is key issue to get the crystal with high quality. Equilibrium partial pressures, pCd and pZn, over Cd1-xZnx melt were estimated based on thermodynamic relationship and then Cd0.9Zn0.1Te wafers were annealed under controlled Cd/Zn partial pressures provided by Cd1-xZnx alloy reservoir. The experimental results show that when CdZnTe wafers are annealed under the equilibrium partial pressures provided by Cd0.99Zn0.01 alloy reservoir for 5 days or more at 1073 K, the resistivity of the wafer can be raised by 6 times and IR transmittance raised by 10% or more, the size and density of Te precipitates are greatly reduced. Moreover, losing of Zn from the surface can be avoided, which Ieads to improvement of the Zn radial distribution. In addition, the relationship between the electrical performances of the wafers and different controlled pressures is also discussed.

关键词： CdZnTe annealing Partial pressures over Cd_1-xZn_x γ-ray detector

Modeling Study of the Particle Pinning Effect on the Grain Boundary Movement

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 342-345页

作者： WANG Xue-lun 1,FU Li-ming 2,WANG Wei 3,JIA Zhi-xin 1 (1.Rizhaosteel Technology Center,Rizhao Iron and Steel Co Ltd.Rizhao 276806,china 2.School of Materials science and engineering,shanghai jiaotong university,shanghai 200240 china 3 Department of Structural Steels,Baosteel Research Institute,shanghai 201900,china) Rizhao Iron & Steel Co Ltd Rizhaosteel Technol Ctr Rizhao 276806 Peoples R China shanghai Jiao Tong Univ Sch Mat Sci & Engn Shanghai 200240 Peoples R China Baosteel Res Inst Dept Struct Steels Shanghai 201900 Peoples R China

In this work,based on the classical grain boundary (GB) formula and the principle of work-energy conversion,a new physically-based model has been developed to predict the particle pinning force concerning the interaction between second phase particles (SPPs) and the moving *** effect of particles pinning on the GB movement is *** modeling results can be applied to quantitatively determine the critical numbers of SPPs required for complete pining the grain growth,such as the critical SPPs number of the unit GB area,the critical number for single grain stagnation,the critical volume fraction of particles at a given particle *** predictions are in good agreement with the experimental results by Gladman.

关键词： the second-phase particle pinning force physical-based model

NUMERICAL SIMULATION OF HEATING AND QUENCHING PROCESSES FOR A 280 CONNECTING ROD OF 16V280ZJ DIESEL LOCOMOTIVE

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2002年第6期15卷 561-568页

作者： J.S. Ye, Z.R. Ye, A. Yang,and Y.LuaSchool of Materials science and engineering, shanghai jiaotong university, shanghai 200030, china Ziyang Internal-Combustion Factory of Sichuan, Ziyang 641000, china Sch. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China Ziyang Internal-Combustion Factory Ziyang 641000 China

A modified temperature-phase transformation-stress coupled 3D non-linear mathematical model and a series of subroutines on the non-liner MARC (MARC Analysis Research Corporation) are developed. Then this modified model has been utilized to simulate the heat treatment processes of 280 connecting rod of 16 V280ZJ diesel locomotive. The simulation results are basically in agreement with the experiments, which testify that the mathematical model and method are feasible. In addition, the simulation can not only obtain the transient temperature and micro structure of heat treatment process, but also provide a sound scientific basis for the heat treatment workers.

关键词： non-linear transient temperature phase transformation mathematical model

Effect of Solute Drag and Precipitate Pinning on Austenite Grain Growth in Ti-Nb Microalloyed Steels

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 383-387页

作者： FU Li-ming 1,WANG Huan-rong 2,WANG Wei 2,SHAN Ai-dang 1 (1.School of Materials science and engineering,shanghai jiaotong university,shanghai 200240,china 2.Department of Structural Steels,Baosteel Research Institute,shanghai 201900,china) shanghai Jiao Tong Univ Sch Mat Sci & Engn Shanghai 200240 Peoples R China Baosteel Res Inst Dept Struct Steels Shanghai 201900 Peoples R China

A metallurgical model concerning the co-effect of the Nb solute drag and the complex carbonitride precipitates pinning is proposed to predict the recrystallization austenite grain growth of low carbon Nb-containing microalloyed *** analysis,both predicted and experimental,reveals the precipitate pinning plays a dominate role in suppressing the austenite grain growth with less Nb solute drag effect in high temperature region whereas the Nb solute drag predominates in relatively low temperature region.A factor p is suggested to assess the effectiveness of drag and *** pinning and the drag are more effective in restraining grain growth as p>0 and p<0,respectively.A low carbon Nb microalloyed steel and a kind of Ti-modified low carbon Nb steel by Ti substituting for part of Nb are employed to validate the modeling *** theoretical calculations show a good agreement with experimental results.

关键词： grain growth precipitates pinning solute drag Ti-Nb microalloyed steels

Parametric Vibration and Vibration Reduction of Cables in Cable-stayed Space Latticed Structure

在线全文

学校读者我要写书评

暂无评论

Journal of shanghai jiaotong university(science) 2008年第2期13卷 145-149页

作者：包艳周岱柳杰 School of Naval Architecture Ocean and Civil EngineeringShanghai Jiaotong University

Mechanical model and vibration equation of a cable in cable-stayed space latticed structure (CSLS) under external axial excitation were *** of the mass lumps and natural frequencies sup- plied by the space latticed structure (SLS) was *** scales method (MSM) was introduced to analyze the characteristics of cable's parametric vibration,and the precise time-integration method (PTIM) was used to solve vibration *** vibration behavior of a cable is closely relative to the frequency ratio of the cable and *** cable's parametric vibration caused by the external axial excitation easily occurs if the frequency ratio of the cable and SLS is in a certain range,and the cable's vibration amplitude varies greatly even if the initial disturbance supplied by SLS changes a ***,the mechanical model and vibration equation of the composite cable system consisting of main cables and assistant cables were studied. The parametric analysis such as the pre-tension level and arrangement of the assistant cables was carried out. Due to the assistant cables,the single-cable vibration mode can be transferred to the global vibration mode, and the stiffness and damping of the cable system are *** natural frequencies of the composite cable system with the curve line arrangement of assistant cables are higher than those with the straight-line arrangement and the former is more effective than the latter on the cable's vibration suppression.

关键词： cable parametric vibration composite cable system axial excitation vibration suppression

INFLUENCE OF GRAIN SIZE AND ORDERING OF PARENT PHASE ON M_s IN A CuZnAl ALLOY CONTAINING BORON

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1989年第5期2卷 326-332页

作者： WU Jianxin JIANG Bohong XU Zuyao (T.Y.Hsu) shanghai jiaotong university,shanghai,china Associate Professor,Dept.of Materials science and engineering,shanghai jiaotong university,shanghai,china

The effect of grain size and ordering of the parent phase on the critical points of thermoelastic martensitic transformation in Cu-25.62 Zn-3.97 Al-0.0018 B(wt-%)shape memory alloy has been *** on the thermodynamics of phase transformation,a linear rela- tionship between the starting temperature of martensitic transformation and the reciprocal of the square root of grain size is obtained,i.e.M_s temperature rises with increasing grain size. It shows a good agreement with the results of electric resistance *** the Landau's theory,a quantitative relationship between M_s and the ordering parameter of the parent phase is set up,which is well confirmed by the results of X-ray diffraction and electric resistance *** activation energy of the ordering process in the parent phase of the alloy is calculated to be 46 kJ/mol.

关键词： Cu-Zu-Al shape memory alloy thermoelastic martensite grain size ordering

Constructing Product Ontologies with an Improved Conceptual Clustering Algorithm

在线全文

学校读者我要写书评

暂无评论

Journal of Systems engineering and Electronics 2002年第3期13卷 71-77页

作者： Cao Dajun & Xu Liangxian Department of computer science, shanghai jiaotong university, shanghai 200030, P.R. china Department of computer science Shanghai Jiaotong University Shanghai 200030 P. R. China

In a distributed eMarketplace, recommended product ontologies are required for trading between buyers and sellers. Conceptual clustering can be employed to build dynamic recommended product ontologies. Traditional methods of conceptual clustering (e.g. COBWEB or Cluster/2) do not take heterogeneous attributes of a concept into account. Moreover, the result of these methods is clusters other than recommended concepts. A center recommendation clustering algorithm is provided. According to the values of heterogeneous attributes, recommended product names can be selected at the clusters, which are produced by this algorithm. This algorithm can also create the hierarchical relations between product names. The definitions of product names given by all participants are collected in a distributed eMarketplace. Recommended product ontologies are built. These ontologies include relations and definitions of product names, which come from different participants in the distributed eMarketplace. Finally a case is given to illustrate this method. The result shows that this method is feasible.

关键词： Machine learning Conceptual clustering Product ontologies Electronic marketplace.

Bayesian cognitive trust model based self-clustering algorithm for MANETs

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第3期53卷 494-505页

作者： WANG Wei1,2,3 & ZENG GuoSun1,2,31Department of computer science & Technology, Tongji university, shanghai 200092, china 2Tongji Branch, National engineering & Technology Center of High Performance computer, shanghai 200092, china 3Key Loboratory of Embedded System and Service Computing, Ministry of Education, shanghai 200092, china Department of computer science & Technology Tongji University Shanghai China Tongji Branch National Engineering & Technology Center of High Performance Computer Shanghai China Key Loboratory of Embedded System and Service Computing Ministry of Education Shanghai China

With the introduction of mobile Ad hoc networks (MANETs), nodes are able to participate in a dynamic network which lacks an underlying infrastructure. Before two nodes agree to interact, they must trust that each will satisfy the security and privacy requirements of the other. In this paper, using the cognition inspired method from the brain informatics (BI), we present a novel approach to improving the search efficiency and scalability of MANETs by clustering nodes based on cognitive trust mechanism. The trust relationship is formed by evaluating the level of trust using Bayesian statistic analysis, and clusters can be formed and maintained autonomously by nodes with only partial knowledge. Simulation experiments show that each node can form and join proper clusters, which improve the interaction performance of the entire network. The essence of the underlying reason is analyzed through the theory of complex networks, revealing great scalability of this method.

关键词： trust model MANET self-clustering Bayesian method cognitive mobile