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Laser-produced plasma helium-like titanium Kα x-ray source and its application to Rayleigh-Taylor instability study
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Several experiments are performed on the ShenGuang-II laser facility to investigate an x-ray source and test radiography concepts.X-ray lines emitted from laser-produced plasmas are the most practical means of generating these high intensity sources.By using a time-integrated space-resolved keV spectroscope and pinhole camera,potential helium-like titanium Kα x-ray backlighting (radiography) line source is studied as a function of laser wavelength,ratio of pre-pulse intensity to main pulse intensity,and laser intensity (from 7.25 to~11.3×10 15 W/cm 2).One-dimensional radiography using a grid consisting of 5 μm Au wires on 16 μm period and the pinhole-assisted point projection is tested.The measurements show that the size of the helium-like titanium Kα source from a simple foil target is larger than 100 μm,and relative x-ray line emission conversion efficiency ξ x from the incident laser light energy to heliumlike titanium K-shell spectrum increases significantly with pre-pulse intensity increasing,increases rapidly with laser wavelength decreasing,and increases moderately with main laser intensity increasing.It is also found that a gold gird foils can reach an imaging resolution better than 5-μm featured with high contrast.It is further demonstrated that the pinhole-assisted point projection at such a level will be a novel two-dimensional imaging diagnostic technique for inertial confinement fusion experiments. 相似文献
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纤芯失配型光纤传感器折射率敏感特性 总被引:5,自引:3,他引:2
根据菲涅耳公式和功率反射系数关系式,分析纤芯失配型光纤传感器折射率传感原理;采用单模/多模光纤制作传感器,研究传感器输出光功率随甘油溶液折射率变化特征,并验证理论计算结果.表明媒质折射率n2=1.300~1.441时,传感器输出光功率强且几乎不发生变化;nz=1.441~1.452时,传感器输出光功率呈线性快速下降,其斜率为-155.91;当媒质折射率与单模光纤包层折射率接近时,传感器输出光功率几乎为0.验证实验发现,传感器线性快速下降的折射率范围为1.442~1.454,斜率为-49.67,其输出光功率随甘油溶液折射率变化规律与数值模拟结果基本一致.该传感器具有结构简单、成本低、传感系统全光纤化等特点,能用于有毒有害、易燃易爆等特殊环境下物质折射率的高精度测量. 相似文献
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深水柔性缆线是深海资源开采系统的重要组成部分, 随着水深的增加, 深水缆线长径比达103, 结构柔性变得很大, 且沿展向非均匀分布的浮力模块, 使得缆线构型变得更加复杂、张力等结构参数沿展向变化, 这使得环境载荷作用、海面船体运动等激励作用下的缆线流固耦合响应变得更加复杂, 给结构安全带来严峻挑战. 本文针对Double-stepped这种新构型深水缆线, 基于其流固耦合特性和载荷模型表征, 建立了含分布浮体的深水缆线动力学控制方程, 并结合有限元数值模拟和水箱模型实验, 进行了复杂构型缆线的动响应研究. 考察规则波和极端波浪环境载荷作用、海面船体运动等激励因素对结构响应的影响, 给出位移和张力等响应的时空演化规律, 并基于WKB理论分析了变参数结构响应幅值和波长的演化规律和机理. 结果表明: 结构响应沿着缆线长度向下传播过程中非单调变化, 在低张力区域会出现局部峰值; 由于分布浮体的存在使得结构参数轴向变化且不连续, 响应时空演化变得更加复杂, 呈现驻波、行波混合效应, 而且张力不但会影响位移幅值, 还会引起响应传播过程中的波长改变. 相似文献
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提出一种基于径向基函数神经网络模型来重构蜕化的光纤光栅应变传感器的方法.以结构健康监测系统中应变测量系统的光纤光栅应变传感器之间关联分析为基础,依据径向基函数神经网络强大的函数逼近能力,利用关联度高、运行良好的应变传感器去重构蜕化的应变传感器,保证重构的应变传感器与蜕化传感器有较高的数据准确度.实验结果证实了该方法在理论和实践上的精确性和可行性. 相似文献
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A multichannel fiber-optic Fabry-Perot (F-P) demodulator based on nonscanning correlation demodulation is proposed. The demodulator principle is analyzed, and the prototype of nonscanning correlation demodulation fiber-optic F-P demodulator is made and tested. The measurement range of the prototype is from 10 to 40 μm, the demodulation resolution is 8 nm, and its stability is 7 nm. This method provides a feasible solution, which guarantees the practicability of the fiber-optic F-P sensor network. 相似文献
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针对磁性应力监测研究中力磁耦合关系有多种变化趋势且一直没有合理理论解释这一问题, 从磁性材料的微观磁畴运动出发, 根据磁致磁化过程, 详细分析了两种不同磁化状态下力致磁化的变化规律, 揭示出力磁耦合关系的变化特征, 进而提出磁化状态是导致力磁耦合关系差异的本质因素; 对工程上实际缆索用镀锌钢丝在不同磁化状态下进行了力磁耦合试验, 结果与理论一致: 力磁耦合关系随磁化状态的不同而不同, 本质上有效地解释了已有研究中力磁耦合关系的矛盾多样性.
关键词:
应力监测
磁化状态
力磁耦合
磁畴运动 相似文献