利用薄膜量热计测量高功率Z箍缩软X射线总能量

介绍一种采用脉冲恒压电源驱动的镍薄膜量热计,研制了测量系统和镍薄膜探测器,对探测器的电阻 温度特性进行了实验标定,该量热计已成功应用于测量“强光一号”加速器高功率Z箍缩等离子体软X射线总能量,分析了测量不确定度。     

预脉冲对相对论磁控管工作性能的影响分析

在阐述预脉冲产生的基础上,分析了预脉冲带来的一系列影响,包括工和电压波形变化,提前生成等离子体,以及预脉冲阶段放大竞争模式等,这些影响与相对论磁控管起振工作频率相联系,从而直接造成了相对论磁控管的基本性能参数,如脉宽、工作频率及输出功率等变化。结合具体实验,对比了有、无预脉冲条件下相对论磁控管工作性能的差异,对预脉冲的影响因素与相对论磁控管性能之间的联系进行了详细的分析。     

X光Gabor波带片编码成像技术实验研究

基于星光II实验装置进行了Gabor波带片编码成像探索性实验研究。采用束匀滑光斑三倍频激光打靶,辐照专门设计的ＣＨ埋金属条靶（共两种）,产生了有明确形状、边缘清晰的等离子体。研制了专门的Gabor波带片编码相机,并利用该相机采用单张胶片对不同的靶目标在不同的深度层次上曝光的技术,获得了具有深度层次信息的三维激光等离子体编码像。利用数值重建技术对实验所获得的图像解码,最终获得了在不同深度层次上的激光等离子体信息。     

纵磁作用下真空电弧单阴极斑点等离子体射流三维混合模拟

真空电弧的特性直接受到从阴极斑点喷射出的等离子体射流的影响,对等离子体射流进行数值仿真有助于我们深入了解真空电弧的内部物理机制.然而,磁流体动力学和粒子云网格仿真方法受限于计算精度和计算效率的原因,无法有效地应用于真空电弧等离子体射流仿真模拟.本文开发了一套三维等离子体混合模拟算法,并在此基础上建立了真空电弧单阴极斑点...     

液相放电等离子体特性与激波特性的数值分析

以能量平衡方程为基础,采用不同的电导率唯象模型描述了液相放电等离子体圆柱形通道特性,得到了通道内半径、温度、电阻、电流和耗散能量随时间的变化关系,还给出了距离放电间隙中心一定距离处的冲击波压力变化,并与前人利用等离子体通道球状模型计算得到的结果进行了比较。结果表明：把等离子体通道看成球状和看成圆柱状在描述通道压力和通道半径时差异显著,而在描述其他物理特性时差别不大;三种电导率模型在描述等离子体通道物理特性时,变化趋势大体相同,而在描述激波特性时,电导率模型σ₂更符合实际;通过对比电学参数与压力参数的变化,就可以在实验中根据实验数据以及具体的研究问题进行模型的适用性选择。     

等离子体喷射X光时空分辨测量

在“神光”强激光装置上对０．５３μｍ激光产生的等离子体喷射进行了Ｘ光时空分辨诊断。首次利用多针孔阵列成像技术结合软Ｘ光扫描相机观察激光加热区和Ｘ光加热区等离子体的运动，获得了初级和次级等离子体膨胀速度等结果．     

A rapid and selective HPLC‐UV method for the quantitation of efavirenz in plasma from patients on concurrent HIV/AIDS and tuberculosis treatments

Owing to heterogeneity in therapeutic response, efavirenz is of research and clinical interest. There is a need to quantitate it using noncostly and selective methods. A method for efavirenz quantitation in plasma containing HIV and tuberculosis drugs was developed. Chromatographic separation was carried out using a C₁₈ column. The mobile phase consisted of 0.1% formic acid and acetonitrile, and was pumped at a flow rate of 0.3 mL/min. Efavirenz and ritonavir (internal standard) were monitored at 247 nm. Plasma proteins were precipitated by centrifugation. The analysis time was 6 min. The response was linear (r = 0.9997). The accuracy ranged between 98 and 115% (intraday) and between 99 and 117% (interday). The precision ranged from 1.670 to 4.087% (intraday) and from 3.447 to 13.347% (interday). Recovery ranged from 98 to 132%. Stability ranged between 99 and 123%. The selectivity was proven by analysis of drugs used for the management of HIV/AIDS and tuberculosis. Plasma sample analysis showed an efavirenz retention time of 5.57 min and a peak plasma concentration of 2.4 µg/mL occurring at 2 h. This method is rapid and selective, and thus suitable for monitoring efavirenz in patients with HIV/AIDS alone or co‐infected with tuberculosis in a less resourced setting. Copyright © 2013 John Wiley & Sons, Ltd.     

Observation of thermoluminescence induced by fission fragments

Abstract

Thermoluminescence induced in CaF₂ powder by fission fragments emanating from a uranium foil bombarded by fast neutrons has been measured as a function of neutron fluence. A linear relationship between the glow produced and the fast neutron fluence between 5 × 10¹⁰ and 6.5 × 10¹¹ n/cm² has been obtained, thus establishing the feasibility of the use of this method for fast-neutron dosimetry. A limitation of the method is that, if the fissile foil is not separated from the phosphor after irradiation, the TL produced by the α-disintegration of ²³⁸U may eventually mask the fission-induced TL.     

Quantitative measurement of hard X-ray spectra from laser-driven fast ignition plasma

Absolute Kα line spectroscopy is proposed for studying laser–plasma interactions taking place in the Au cone-guided fast ignition targets. X-ray spectra ranging from 20 to 100 keV were quantitatively measured with a Laue spectrometer composed of a cylindrically curved crystal and a filter-absorption method for Bremsstrahlung continuum emission. The absolute sensitivities of the Laue spectrometer systems were calibrated using pre-characterized laser-produced X-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an X-ray diffraction code. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer mechanism, is derived from this work. The absolute yield of Au and Ta Kα lines were measured in the fast ignition experimental campaign performed at Institute of Laser Engineering, Osaka University. Applying the hot electron spectrum information from electron spectrometer and scaling laws, the energy transfer efficiency from the incident LFEX, a kJ-class PW laser, to hot electrons was derived for the first time.     

Structural characteristics and residual stresses in oxide films produced on Ti by pulsed unipolar plasma electrolytic oxidation

Oxide films, 7–10 µm thick, were produced on commercially pure titanium by plasma electrolytic oxidation in a sodium orthophosphate electrolyte using a pulsed unipolar current with frequency (f) and duty cycle (δ) varying within f = 0.1–10 kHz and δ = 0.8–0.2, respectively. The coatings comprised a mixture of an amorphous phase with nanocrystalline anatase and rutile phases, where the relative rutile content range was 17–25 wt%. Incorporation of phosphorus from the electrolyte into the coating in the form of PO₂ ^–, PO₃ ^2– and PO₄ ^3–, as demonstrated by EDX and FT-IR analyses, contributed to the formation of the amorphous phase. Residual stresses associated with the crystalline coating phase constituents were evaluated using the X-ray diffraction sin² ψ method. It was found that, depending on the treatment parameters, internal direct and shear stresses in anatase ranged from–205 (±17) to–431 (±27) MPa and from–98 (±6) to–145 (±10) MPa, respectively, whereas the rutile structure is comparatively stress-free.