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DONG Yuan ZHANG XiHe JIN GuangYong LING Ming & NING GuoBin School of Science Changchun University of Science Technology Changchun China 《中国科学:物理学 力学 天文学(英文版)》2010,(3)
The far-field propagation properties of conical double half-Gaussian hollow beams in the condition of Collins formula are studied. Because of the cone angle of this kind of hollow beams, the diffraction is compensated and the inner diameter is turning bigger by the rule of geometric optics as the propagation distance is increasing, whereas the degenerating diffraction phenomenon is turned out. The far-field intensity distribution of the conical double half-Gaussian hollow beams in the condition of in-Collin... 相似文献
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Yuan Dong XiHe Zhang GuoBin Ning GuangYong Jin Wei Liang YanFei Lü Kai Zhang 《中国科学G辑(英文版)》2009,52(6):832-837
A new kind of hollow beams, double half-Gaussian hollow beams, was put forward. With the help of the Collins formula, the
analytical equation of propagation and transformation of the hollow laser beams in free space was deduced. The simulation
shows that the intensity exhibits the three-dimensional trap distribution in the near-field, while the double half-Gaussian
hollow beams turn into solid laser beams when propagating a certain distance, which shows the characteristics of self-focus.
The double half-Gaussian hollow beams were obtained by means of the dual-reflecting splitting optical system. The intensity
of the vertical loop in different distances was tested, which shows that the analytical equation of propagation and transformation
is in agreement with the result.
Supported by the National Natural Science Foundation of China (Grant No. KB92009) 相似文献
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将三维热权函数法扩展为适用于表面力、体积力和温度载荷的通用权函数法(UWF).推导出以变分型积分方程表达的UWF法基本方程,从变分的角度,将求解三维热权函数法基本方程的多虚拟裂纹扩展法(MVCE)改造为可以适用于一般的变分型积分方程的一类新型数值方法--有限变分法(FVM).在FVM中可以引入无穷多种线性无关的局部变分模式,可以根据计算要求在求解域中插入任意多个计算节点,单一型裂纹问题FVM所得到的最终方程组的系数矩阵总是一个对称的窄带矩阵,而且对角元总是大数,具有良好的数值计算性能.FVM对于SIF沿裂纹前缘急剧变化的复杂情况具有较好的数值模拟能力和较高的计算精度,利用自身一致性,可以求得三维裂纹前缘SIF的高精度解. 相似文献
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Study on the Absorption of 10TeV γ-Rays Interacting with Soft Photons in Intergalactic Space 下载免费PDF全文
XU XianWu DING LinKai CAO PeiYuan DAI BenZhong FENG ZhenYong FU Yu GUO HongWei HE Mao HUANG Qing HUO AnXiang JIA HuanYu LI JinYu LIU ShaoMin LU Hong LU SuiLing LUO GuangXuan MEI DongMing 《中国物理C(英文版)》2000,24(8):697-701
TeV gamma rays will be attenuated or absorbed due to the interaction with soft photons in intergalactic space. The spectra of Mrk421 and Mrk501 during their flaring have been observed by ACTs. Using the data obtained with Tibet Ⅱ/HD AS array from October of 1995 to Augest of 1997,the preliminary results of energy density of intergalactic infrared radiation field are presented in this paper. Analysis shows that no statistically significant absorption evidence of high energy gamma rays is found up to around 30 TeV. 相似文献