We investigated the dependence of laser-induced breakdown spectral intensity on the focusing position of a lens at different sample temperatures(room temperature to 300 ℃) in atmosphere.A Q-switched Nd:YAG nanosecond...We investigated the dependence of laser-induced breakdown spectral intensity on the focusing position of a lens at different sample temperatures(room temperature to 300 ℃) in atmosphere.A Q-switched Nd:YAG nanosecond pulsed laser with 1064 nm wavelength and 10 ns pulse width was used to ablate silicon to produce plasma. It was confirmed that the increase in the sample's initial temperature could improve spectral line intensity. In addition, when the distance from the target surface to the focal point increased, the intensity firstly rose, and then dropped.The trend of change with distance was more obvious at higher sample temperatures. By observing the distribution of the normalized ratio of Si atomic spectral line intensity and Si ionic spectral line intensity as functions of distance and temperature, the maximum value of normalized ratio appeared at the longer distance as the initial temperature was higher, while the maximum ratio appeared at the shorter distance as the sample temperature was lower.展开更多
针对同一成型装药形成多模毁伤元问题,利用LS-DYNA程序,研究了单点起爆位置对爆炸成型侵彻体(explosively formed penetrator,EFP)成型的影响规律。当起爆点距离药型罩的轴向距离从0倍装药口径增加到0.72倍装药口径,EFP速度提高了37.8%...针对同一成型装药形成多模毁伤元问题,利用LS-DYNA程序,研究了单点起爆位置对爆炸成型侵彻体(explosively formed penetrator,EFP)成型的影响规律。当起爆点距离药型罩的轴向距离从0倍装药口径增加到0.72倍装药口径,EFP速度提高了37.8%,长径比增加了1倍多;优化设计成型装药结构,分析了主装药端面中心点起爆和药型罩顶点起爆爆轰波传播规律,实现了杆式EFP、EFP 2种模态的转换。通过X光成像实验进行了验证,实验结果与数值模拟结果吻合较好。展开更多
基金support by National Natural Science Foundation of China (Grant Nos. 11674128, 11504129, and 11474129)Jilin Province Scientific and Technological Development Program, China (Grant No. 20170101063JC)the Thirteenth Five-Year Scientific and Technological Research Project of the Education Department of Jilin Province, China (2016, No. 400)
文摘We investigated the dependence of laser-induced breakdown spectral intensity on the focusing position of a lens at different sample temperatures(room temperature to 300 ℃) in atmosphere.A Q-switched Nd:YAG nanosecond pulsed laser with 1064 nm wavelength and 10 ns pulse width was used to ablate silicon to produce plasma. It was confirmed that the increase in the sample's initial temperature could improve spectral line intensity. In addition, when the distance from the target surface to the focal point increased, the intensity firstly rose, and then dropped.The trend of change with distance was more obvious at higher sample temperatures. By observing the distribution of the normalized ratio of Si atomic spectral line intensity and Si ionic spectral line intensity as functions of distance and temperature, the maximum value of normalized ratio appeared at the longer distance as the initial temperature was higher, while the maximum ratio appeared at the shorter distance as the sample temperature was lower.
文摘针对同一成型装药形成多模毁伤元问题,利用LS-DYNA程序,研究了单点起爆位置对爆炸成型侵彻体(explosively formed penetrator,EFP)成型的影响规律。当起爆点距离药型罩的轴向距离从0倍装药口径增加到0.72倍装药口径,EFP速度提高了37.8%,长径比增加了1倍多;优化设计成型装药结构,分析了主装药端面中心点起爆和药型罩顶点起爆爆轰波传播规律,实现了杆式EFP、EFP 2种模态的转换。通过X光成像实验进行了验证,实验结果与数值模拟结果吻合较好。
