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Design of Electrostatic Focusing for Space Electron Beam Welding Gun 被引量:2
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作者 李春旭 何成旦 +1 位作者 许启晋 蒋彩云 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2005年第3期256-262,共7页
The developmental situation of space welding technology at home and abroad is introduced. Then it is put forward that the designing scheme and the computer aided design (CAD) method of main single lens of the domest... The developmental situation of space welding technology at home and abroad is introduced. Then it is put forward that the designing scheme and the computer aided design (CAD) method of main single lens of the domestic space electron beam gun with equal-diameter three-cylinder simple lens, and the flowing-pipe way of calculating the space charge density of the main lens area ,in the electron gun is analyzed. The parameters calculation of the focusing system is completed through Language C utilizing computer programming and a satisfying result is gotten. The result shows that the calculation and design method are correct : the dispersed focusing current of electron beam is less, the beam section is less in the deflected magnetic field, the minimal radius of beam spot on the workpiece is about 0.65615mm, and all these can meet the requirements of the space welding and cutting. 展开更多
关键词 space welding three-cylinder single lens CAD space charge effect
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THREE-SPHERE INEQUALITIES FOR SECOND ORDER SINGULAR PARTIAL DIFFERENTIAL EQUATIONS
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作者 张松艳 《Acta Mathematica Scientia》 SCIE CSCD 2010年第3期993-1003,共11页
In this article, we give the three-sphere inequalities and three-ball inequalities for the singular elliptic equation div(A∨u) - Vu =0, and the three-ball inequalities on the characteristic plane and the three-cyli... In this article, we give the three-sphere inequalities and three-ball inequalities for the singular elliptic equation div(A∨u) - Vu =0, and the three-ball inequalities on the characteristic plane and the three-cylinder inequalities for the singular parabolic equation Эtu-div(A∨u) + Vu = 0, where the singular potential V belonging to the Kato-Fefferman- Phong's class. Some applications are also discussed. 展开更多
关键词 Three-sphere inequality three-cylinder inequality singular partial differential equation Kato-Fefferman-Phong's class Lipschitz domain
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