期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
Interference Diagnosis of the Initial Stage of Laser-Produced-Plasma in Air 被引量:1
1
作者 HE Anzhi LU Jian ni xiaowu 《Chinese Physics Letters》 SCIE CAS CSCD 1991年第11期574-577,共4页
By using a Q-switched YAG laser and an optical path delay set-up,we study the process in which a Jaser induces breakdown to produce plasma in air,and obtain time-resolved Mach-Zehnder interferograms and opt ical sh ad... By using a Q-switched YAG laser and an optical path delay set-up,we study the process in which a Jaser induces breakdown to produce plasma in air,and obtain time-resolved Mach-Zehnder interferograms and opt ical sh adowgrams of the initial stage of the plasma and the expansion wave produced in the process for the first time. 展开更多
关键词 SWITCHED BREAKDOWN INTERFERENCE
下载PDF
毫秒激光致固体靶材熔融喷溅的比较实验研究 被引量:2
2
作者 张梁 倪晓武 陆健 《激光技术》 CAS CSCD 北大核心 2018年第4期446-450,共5页
为了研究毫秒激光致硅靶的熔融喷溅机理,采用阴影法,通过高速CCD获得了毫秒激光与固体靶材(硅靶和铝靶)相互作用的序列阴影图,研究了毫秒激光致固体靶材的融熔喷溅过程。实验上对比了毫秒激光致硅靶和铝靶熔融喷溅过程的不同,并对毫秒... 为了研究毫秒激光致硅靶的熔融喷溅机理,采用阴影法,通过高速CCD获得了毫秒激光与固体靶材(硅靶和铝靶)相互作用的序列阴影图,研究了毫秒激光致固体靶材的融熔喷溅过程。实验上对比了毫秒激光致硅靶和铝靶熔融喷溅过程的不同,并对毫秒激光致固体熔融喷溅形成的机制进行了讨论。根据两种靶材融熔喷溅机理不同,解释了两种靶材融熔喷溅物的形貌、喷溅角度、喷溅物分布和喷溅物亮度不同的原因。结果表明,毫秒激光对两种靶材均能产生气化和熔融喷溅过程,但气化强度和熔融喷溅物的形态、亮度均不相同;激光作用硅靶时,作用区域所产生的气化现象不明显,熔融喷溅物呈液滴状,其亮度强于背景光,熔融喷溅方向与靶材前表面法线所成角的最大值为45°,熔融喷溅物分布在其间;而激光作用铝靶时,作用区域的铝靶所产生的气化现象更加明显,熔融喷溅物呈线状不透明流体,其亮度低于背景光,熔融喷溅方向与靶材前表面法线所成角度为20°,熔融喷溅物分布在熔融喷溅方向所在的直线周围。该研究对激光加工技术是有帮助的。 展开更多
关键词 激光物理 熔融喷溅 阴影法 气化 毫秒激光
下载PDF
飞秒光丝阵列对10GHz电磁波的吸收特性 被引量:2
3
作者 孙中浩 董超 +3 位作者 张亚春 何湘 倪晓武 骆晓森 《强激光与粒子束》 EI CAS CSCD 北大核心 2018年第5期77-82,共6页
为了研究飞秒光丝阵列对10GHz电磁波的吸收特性,建立了飞秒光丝阵列吸收电磁波的有限元模型,研究了光丝内电子温度、电子数密度、光丝直径和电磁波的极化等参数对吸收系数的影响。研究结果表明:当电磁波偏振方向与光丝轴向垂直时,阵列... 为了研究飞秒光丝阵列对10GHz电磁波的吸收特性,建立了飞秒光丝阵列吸收电磁波的有限元模型,研究了光丝内电子温度、电子数密度、光丝直径和电磁波的极化等参数对吸收系数的影响。研究结果表明:当电磁波偏振方向与光丝轴向垂直时,阵列对电磁波是透明的;增加光丝内电子数密度或提高电子温度,吸收系数先增大后减小;当光丝直径与电磁波趋肤深度相等时,吸收系数达到最大值。对于S极化电磁波,当光丝直径为50μm时,吸收系数随入射角的增大而变大;当光丝直径为100~200μm时,在入射角较小时,吸收系数随入射角的增大而变大;在入射角较大时会出现吸收峰值,最高可达0.45,且光丝直径越大,吸收峰值对应的入射角就越小;对于P极化电磁波,吸收系数随入射角增大而降低。 展开更多
关键词 飞秒光丝 阵列 电磁波 吸收系数 趋肤深度
下载PDF
激光等离子体丝阵列对10GHz微波传输特性的影响 被引量:1
4
作者 董超 孙中浩 +3 位作者 张亚春 何湘 倪晓武 骆晓森 《红外与激光工程》 EI CSCD 北大核心 2018年第10期160-167,共8页
为了研究飞秒激光等离子体丝阵列对10 GHz微波传输特性的影响,利用COMSOL软件构建了飞秒激光等离子体丝阵列与微波相互作用的数值仿真模型,研究了等离子体丝阵列参数、等离子体特征参数、阵列层数对微波反射率和透射率的影响。数值结果... 为了研究飞秒激光等离子体丝阵列对10 GHz微波传输特性的影响,利用COMSOL软件构建了飞秒激光等离子体丝阵列与微波相互作用的数值仿真模型,研究了等离子体丝阵列参数、等离子体特征参数、阵列层数对微波反射率和透射率的影响。数值结果表明:当微波的电场方向垂直于等离子体丝轴向时,无论微波相对于丝阵列的入射角如何变化,丝阵列对微波完全没有影响。增加丝的直径或者电子数密度、减少阵列间距或者电子温度都可以使反射率增加,透射率减小。光丝直径为500μm,阵列间距为1 mm的等离子体丝阵列对10 GHz微波反射率最大可达到0.88,此时等离子体的特征参数为ne=1×1023m-3,Te=0.3 e V。当增加丝阵列的层数时,透射率减小,最终趋近于0,而反射率则保持不变。该研究结果对飞秒激光等离子体丝阵列屏蔽干扰微波具有重要意义。 展开更多
关键词 飞秒激光等离子体丝 阵列 反射率 透射率
下载PDF
Detection of Plasma Produced in the Interaction Between YAG Laser and CCD
5
作者 ni xiaowu LU Jian HE Anzhi 《Chinese Physics Letters》 SCIE CAS CSCD 1994年第3期129-132,共4页
A Q-switched YAG laser is used to act repeatedly upon a charge-coupled devices(CCD)having metal-oxide-semiconductor structure,and plasmas in the process are investigated by a Mach-Zehnder interferomcter.According to t... A Q-switched YAG laser is used to act repeatedly upon a charge-coupled devices(CCD)having metal-oxide-semiconductor structure,and plasmas in the process are investigated by a Mach-Zehnder interferomcter.According to the production and development of the plasmas,the damage mechanism of the optoelectronic device is analyzed. 展开更多
关键词 SWITCHED OPTOELECTRONIC repeatedly
下载PDF
Study of mode transformation and energy attenuation of wedge waves with different apex angles by laser ultrasonic techniques 被引量:1
6
作者 JIA Jing WANG LiJuan +2 位作者 SHEN ZhongHua YUAN Ling ni xiaowu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第4期593-598,共6页
This research focuses on measuring the mode transformation and energy attenuation of wedge waves for different apex angle wedges by using laser ultrasound techniques.Pulsed laser excitation and optical deflection beam... This research focuses on measuring the mode transformation and energy attenuation of wedge waves for different apex angle wedges by using laser ultrasound techniques.Pulsed laser excitation and optical deflection beam methods for detection were used to measure the wedge waves.In experiment,various wedge waves at different locations were recorded by scanning the excitation laser along the wedge tip,and different orders of wedge waves were observed.By fixing the distance between the excitation and detection positions and scanning the samples along the direction normal to the wedge tip,the modes transformation process was obtained.It was found that the energy of the acoustic waves for 20°,25° and 30° wedges decreased exponentially to a steady energy of Rayleigh wave within the main wavelength range of the acoustic modes,while the energy of acoustic waves of 45° and 60° wedge remained stable as the propagation line was scanned away from the wedge tip. 展开更多
关键词 wedge waves laser ultrasonic mode transformation energy attenuation
原文传递
Numerical simulation and experimental detection of leaky Lamb waves induced by pulse laser at air-solid interfaces
7
作者 ZHAO Yan SHEN ZhongHua +1 位作者 LU Jian ni xiaowu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2008年第6期607-616,共10页
Based on the thermoelastic mechanism of laser ultrasonic, the problems of the thermal conduction and the coupling between the motion of solid and fluid are solved by using the finite element method. And then the trans... Based on the thermoelastic mechanism of laser ultrasonic, the problems of the thermal conduction and the coupling between the motion of solid and fluid are solved by using the finite element method. And then the transient waveforms of leaky Lamb waves induced by pulse laser action on the air-aluminum interface are obtained. Experimental signals of laser-induced leaky Lamb waves at the air-alu- minum interface are detected by applying an our-developed detector, based on the light deflection principle. The dispersion and attenuation properties of leaky Lamb waves are analyzed through the phase spectral analysis. 展开更多
关键词 laser ULTRASONIC leaky LAMB wave air-solid interface FINITE ELEMENT method light DEFLECTION
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部