J.Wang School of Mechanical
,
Manufacturing and Medical Engineering
,
Queensland University of Technology
,
GPO Box 2434
,
Brisbane
,
Qld. 4001
,
Australia
金属学报(英文版)
An experimental investigation is outlined for the CO 2 laser cutting process of metallic coated sheet steels, GALVABOND. It shows that by proper control of the cutting parameters, good quality cuts are possible at high cutting rate. Visual examination indicates that when increasing the cutting rate to as high as 5000 mm/min (about 100 times that suggested previously), kerfs of better quality can be achieved. Some kerf characteristics such as the width, heat affected zone and dross in terms of the process parameters are also discussed. A statistical analysis has arrived at a recommendatio on the optimum cutting parameters forprocessing GALVABOND.
关键词:
laser cutting
,
null
,
null
Solid State Communications
Considering the image potential, we calculate the binding energies of a shallow donor impurity placed on the centre of a quantum box using the variational approach. The results we have obtained show that there is a great difference of the effects of image potential between the cases including impurity ion image potential and including the image potentials of impurity ion and electron simultaneously. The results also show that the image potential is important, especially when the dimensions of quantum box become small.
关键词:
well;gaas-ga1-xalxas;states
L. H. Lang
,
D. C. Kang
,
S. H. Zhang
,
Z. R. Wang
,
S. J. Yuan
,
K. B. Nielsen and J. Dancket 1) Department of Materials Engineering
,
Harbin Institute of Technology
,
Harbin 150001
,
China 2) Aalberg University
,
Denmark
金属学报(英文版)
In this paper, the forming features of tapered rectangular box during hydrodynamic deep drawing are studied by means of FEM.The effect rules of square blank corner corner amount on body wrinkling are recognized and corresponding methods are discussed. At last, the results of FEM are verified by experi- ment.
关键词:
sheet metal forming
,
null
,
null
Qunqiang FU
材料科学技术（英文）
At first, a series of finite element method (FEM) simulation tests were used to find the critical forming conditions of hot-galvanized sheet steel during the rectangular box drawing processing when constant blank holder forces were applied. According the test results, the reasonable alteration scope of initial variable blank holder force (VBHF) was as 1.9~2.3 T. Then, based on the test productions of blank holder force, 12 typical VBHF curves were applied to perform the simulation tests by the simulation software of DYNAFORM. The simulation test results showed that VBHF had great effects on drawing formability of hot-galvanized sheet steel during the rectangular box drawing. However, the different VBHF curves were applied to control the whole drawing and it would get great different effects. At the same tine, the VBHF had great effects on the maximum thick thinning ratio, but had little effect on the maximum thick incrassation ratio. So, reasonable application of the VBHF would greatly decrease the fractures. When the VBHF profile is taken as curve L, the best effect of drawing formability could be obtained. When curve I is used, contrary effect could be gotten. The other types of curves would cause effects between above two types of VBHF curves. Finally, the actual tests were applied to check the validity of the FEM simulation tests. The results show that the FEM simulation tests are good ways for predicting and optimizing the VBHF.
关键词:
Drawing process
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变压边力
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热镀锌钢板
王茹
,
张正选
,
俞文杰
,
毕大炜
,
陈明
,
刘张李
,
宁冰旭
功能材料与器件学报
doi:10.3969/j.issn.1007-4252.2011.02.017
本研究工作采用硅离子注入和高温退火工艺对SIMOX材料的BOX层进行总剂量辐射加固.辐射实验结果证明了该加固方法的有效性.PL谱和HRTEM图像显示了硅离子注入及退火工艺在材料的BOX层中引入了Si纳米晶,形成电子陷阱能级,有效俘获电子,从而提高了材料BOX层的抗总剂量辐射能力.
关键词:
绝缘体上硅
,
注氧隔离
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总剂量辐照
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纳米晶
Microelectronics Journal
The Stark shift of the electronic energy levels in semiconducting rectangular quantum boxes with different sizes is investigated by the use of variational solutions to the effective-mass approximation for electric fields of various orientations with respect to the center axis of the box. The asymptotic expansions of the Stark shift are given in the limits of low and high fields, respectively; they clearly indicate that the Stark shift is a quadratic function of the electric field for low electric fields and is an approximate linear function of the electric field for high electric fields. Likewise, our results also show that the largest Stark shift is obtained for the field directed along the diagonal in a cubic box, and is found for the low field directed along a side of the box and for the high field along the diagonal in a rectangular one. The large Stark shift of the electron and hole trapped in a quantum box leads to an obvious reduction of the interband recombination. (C) 2008 Elsevier Ltd. All rights reserved.
关键词:
quantum boxes;Stark effect;optical-absorption;exciton energies;field;well;wires
刘晓东
,
李著信
腐蚀与防护
doi:10.3969/j.issn.1005-748X.2007.09.018
将灰色系统理论与时间序列分析方法结合,建立灰色组合模型.引入Box-Jenkins模型,对随机性成分建模.应用灰色组合模型预测管道腐蚀速率的变化趋势,通过实例分析,检验了该模型的预测效果,并与其它几种方法比较,得出其精度非常高的结论.
关键词:
灰色模型
,
时间序列
,
管道
,
腐蚀速率
,
预测
