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The normal hypervelocity impact of an Al-thin plate by an Al-sphere was numerically simulated by using the adaptive smoothed particle hydrodynamics (ASPH) method. In this method, the isotropic smoothing algorithm of standard SPH is replaced with anisotropic smoothing involving ellipsoidal kernels whose axes evolve automatically to follow the mean particle spacing as it varies in time, space, and direction around each particle. Using the ASPH, the anisotropic volume changes under strong shock condition are captured more accurately and clearly. The sophisticated features of meshless and Lagrangian nature inherent in the SPH method are kept for treating large deformations, large inhomogeneities and tracing free surfaces in the extremely transient impact process. A two-dimensional ASPH program is coded with C . The developed hydrocode is examined for example problems of hypervelocity impacts of solid materials. The results obtained from the numerical simulation are compared with available experimental ones. Good agreement is observed. 相似文献
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强恩芳 《中国职业技术教育》2007,(3):17-18
沧州经济技术开发区(以下简称沧州开发区)是1992年7月河北省人民政府批准成立的省级经济技术开发区。沧州开发因临近沧州市区,处在城乡结合部,总体规划面积15.16平方公里,是沧州市重点发展的新型工业区。沧州开发区现辖五村,截至2004年底,共有人口7371人,全部为农业人口。该区人均耕地由1993年的1.9亩,下降到2004年的不足1亩,且呈加速下降趋势;人均收入由1994年的1184元,增长到1998年的人均2602元后,却于1999年直线下降到2083元,之后又逐年上升,直至2004年达到2711元。五村的部分农村劳动力通过兴办企业、外出务工、到乡镇企业工作、家庭养殖种植,或者自办家庭作坊等形式积极自主地实现了劳动力转移,但还有相当多的农村富余劳动力需要通过政府的培训、引导与帮助向非农产业转移。[第一段] 相似文献
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体育理论课是体育教学的重要组成部分,面对学生体质下滑的严峻形势,体育教师应从长远的角度,看清目前体育理论教学中存在的问题,寻求解决问题的方法,并逐步转变认识上的不足,积极激发学生学习的兴趣,不断提高学生锻炼的热情,进一步促进学生的身心全面发展。 相似文献
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在高等职业教育中应用现代教育技术,充分发挥其在教学中的作用,已经成为学校教育手段现代化的重要标志。把多媒体技术应用于教学,制成教学课件,是精品课程建设的重要组成部分。本文就多媒体课件的制作,运用,实现教学过程更新等方面进行了探讨。 相似文献
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The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE. 相似文献
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促进都江堰旅游发展的若干思考 总被引:1,自引:0,他引:1
本文分析了都江堰旅游资源现状及存在问题,并在此基础上提出了促进都江堰旅游发展的若干思路与建议。 相似文献