材料期刊网

1. 首页
2. 检索结果页

原词结果 | 译词结果

PREPARATION AND STRVCTURAL EVOLUTION OF TiO_2 THIN FILMS BY LOW PRESSURE MOCVD

W.J. Li , Z.M. Wu , J.F. Zhao , Z.H. Wu , X.L.Zhao and B.C. Cai ( Information Storage Research Center , Shanghai Jiaotong University , Shanghai 200030 , China , College of Chemical Engineering & Technology , Taiyuan University of Technology , Taiyuan 030024 , China)

金属学报(英文版)

Titanium dioxide thin films were prepared by low pressure metal organic chemical vapor deposition (LP-MOCVD) from titanium IV isopropoxide. Nitrogen was used as a carrier gas for the titanium precursor,and oxygen as a reactant gas. The deposition rates of the films have been studied as functions of process parameters such as sabstrate temperature and oxygen flow rote. Structural evolution of the films has been studied as functions of substrate temperature (110 to 700℃) and annealing temperature. The films have been characterized by X-ray dissection and by Raman scattering. Films deposited onto Si(100) substrates were amorphous at 110-250℃, anatase at 350- 550℃ and rutile above 650℃. The films deposited at substrate temperatures less than 550℃ and annealed at 600℃ for two hours were annealed, annealed at 700℃ for two hours were mixtures of anatase and rutile, and annealed at 850℃ for two hours were rutile.

关键词: MOCVD , null , null , null , null

PHYSICAL SIMULATION BASED INTELLIGENT SYSTEM FOR THE PREDICTION OF SHEET METAL DRAWING CAPABILITY

$ D.L* , D.N.He , X.J.Bao , Y. Q.Zhang , X. Y.Ruan , J.L. Cheng and J. Y. Jiang 1) National Die & Mold CAD Engineering Research Center , Shanghai Jiaotong University , Shanghai 200030 , China 2) Shanghai Volkswagen Automotive Company Limited , Shanghai 201805 , China

金属学报(英文版)

With the combination of a new theoretical formula, physical simulation experiments, the technology of artificial neural network and database, an intelligent system for the prediction of sheet metal drawing capability is constructed for the first time. A modified criterion for sheet metal drawing capability is proposed in this paper, namely, the Technological Limiting Drawing Ratio, TLDR = f(R, n, s, t, F, μ,r_d,r_p…). Based on the studies of other scholars, a new formula is derived to predict the TLDR in this paper. Then a series of orthogonal physical simulation experiments are designed to investigate the effect of technological parameters on the TLDR, and the results are analyzed in the paper. Then the predicting system is constructed with the combination of the theoretical formula, orthogonal experiments, the technology of artifocial neural network and database. The predicted results show good agreements with experimental data, so it can be used to avoid the blindness in the selection of sheet metal before stamping. The system operates under the Windows operating system, and it supports the mechanism of Client/Server as well as Intranet, so the system has high engineering value.

关键词: TLDR , null , null , null , null , null , null

NUMERICAL SIMULATION FOR MEASURING ATMOSPHERE CARBON POTENTIAL BY ELECTRIC RESISTANCE METHOD

W.M. Zhang , M.J. Hu , Y.J. Li , J.S. Pan and X. Chen( 1) Open Lab. of the Educational Ministry for High Temperature Material and Test , Shanghai Jiaotong University , Shanghai 200030 , China 2) Oregen Graduate Institute of Science and Technology , USA)

金属学报(英文版)

According to computer numerical simulation for measuring atmosphere carbon potential by electric resistance method (hot-wire method) and the experimental data, the paper point out that the measuring result dose not directly reflect the atmosphere carbon potential (Cg) but the average carbon content, and as a result, the change of electric resistance obviously lag to that of the atmosphere carbon potential. In order to correctly control the carbon potential by electric resistance method, the authors bring forward a function which is a better expression for the relationship between the average carbon content of the wire and the atmosphere carbon potential and ensures good carbon potential control.

关键词: electric resistance method , null , null

ON THE DYNAMIC CHARACTERISTICS OF MOULD-FILLING UNDER COUNTERGRAVITY

J.M Zeng , H. Gu and YH. Zhou (Institute of Materials Science , Guangxi University , Nanning 530004 , China Department of Materials Science and Engineering , Shanghai Jiaotong University , Shanghai 200030 , China)

金属学报(英文版)

In this paper, the mathematical models for mould-filling under counteramvity are derived on the basis of the principle of momentum. Dynamic processes of mould-filling are observed on a perspex model by means of high speed photography. The results indicate that the mould-filling under counterpmvity can be described by the second oofer nonlinear dtherential equations charucterized by damping oscillations. The velocity oscillations amplofy as the pressuring speed increases if the pressure differential functions are of the same type. On the other hand, if the functions are of different type,then the velocity oscillations depend upon whether the functions pmpressively increase or decrease. Velocity oscillations can be diminished dmmatically by increasing the local damping within the gating system.

关键词: casting , null , null

Energy Minigaps in the Quantum Well Wires with Periodical Lateral Surface Structures

Zhenyan DENG , Hong SUN , and Shiwei GU (Dept. of Applied Physics , Shanghai Jiaotong University , Shanghai , 200030 , China)(To whom correspondence should be addressed)(Present address: No .5 Dept.. Shanghai Institute of Ceramics.Chinese Academy. of Sciences.

材料科学技术（英）

Energy minigaps caused by lateral surface structures in quasi-one-dimensional GaAs/ AlAs quantum well wires are calculated with the variational and degenerate-perturbational approaches.By a coordinate transformotion. the structured interfaces of the wires are transformed into planar ones so that the boundary conditions of the electronic wave functions can be satisfied exactly on the interfaces. The dependence of the energy minigaps on the lateral surface structures are discussed.

关键词:

HIGH STRAIN RATE SUPERPLASTICITY IN A SiC_w/2024Al COMPOSITE MADE BY SQUEEZE CASTING

X.J.Xu , D. Zhang , Z.L. Shi , C.Z.Zhao and R.J. Wu (State Key Laboratory of Metal Matrir Composites , Shanghai Jiaotong University , Shanghai 200030 , China)

金属学报(英文版)

In this paper,the superplastic characteristics of the beta-SiC whisker reinforced 2024aluminum composite, fabricated by squeeze casting and hot-rolling after extrusion were investigated. The compsite had a fine grain size of about 2μm, and exhibited a strain rate sensitivity of about 0.35 and a maximum elongation of 350% at an initial strain rate of 1.1×10-1s-1 at 803K. In addition, the superplastic deformation mechanisme of the composite were also examined.

关键词: high strain rate superplasticity , null , null

Temperature Effects on the Self-trapping Energy of a Polaron in a GaAs Parabolic Quantum Dot

Kadi ZHU and Shiwei GU (Institute of Condensed Matter Physics , Shanghai Jiaotong University , Shanghai , 200030 , China)(To whom correspondence should be addressed)

材料科学技术（英）

The temperature and the size dependences of the self-trapping energy of a polaron in a GaAs parabolic quantum dot are investigated by the second order Rayleigh-Schrodinger perturbation method using the framework of the effective mass approximation. The numerical results show that the self-trapping energies of polaron in GaAs parabolic quantum dots shrink with the enhancement of temperature and the size of the quantum dot. The results also indicate that the temperature effect becomes obvious in small quantum dots

关键词:

出版年份

刊物分类

相关作者

相关热词