Direct determination of gas velocity and gas temperature in an atmospheric-pressure argon-hydrogen plasma jet

Direct gas temperature and gas velocity measurements made in the exit plane of a subsonic argon-hydrogen thermal plasma jet from high-resolution lineshape analysis of laser light scattered by the plasma are reported. The lineshapes are in general a superposition of the ion feature of the Thomson-scattered light and the lineshape of Rayleigh scattered light. In the center of the jet Thomson scattering dominates while at larger radii Rayleigh scattering dominates. Because of the complexity of the lineshapes of light scattered by multicomponent plasmas, only those that are predominantly due to Thomson scattering can in practice be analyzed for gas temperature. Gas velocity can be determined from the Doppler shift of the lineshapes relative to the frequency of the incident laser if the velocity is greater than about 50 m s⁻¹. The maximum gas temperature measured was 14,500 K±5%. The maximum gas velocity measured was 1100 m s⁻¹±3%. Temperature values and the radial velocity profile are compared with those previously obtained from a subsonic all-argon plasma jet operated under similar conditions.     

激光溅射Cu等离子体与气相CH3CN团簇的反应

用激光溅射 -分子束技术研究了Cu等离子体与乙腈团簇的气相反应 .观察到Cu+ (CH3 CN) n、CH2 CN+ (CH3 CN) n、H+ (CH3 CN) n 和CH3 CHCN+ (CH3 CN) n 四个种类的团簇离子 .考察了等离子体作用于脉冲分子束的不同位置 ,对团簇产物的种类和尺寸大小的影响 .实验结果表明 ,Cu+ (CH3 CN) n 是由Cu+ 与乙腈团簇直接缔合而成 ,CH2 CN+ (CH3 CN) n、H+ (CH3 CN) n 主要是激光等离子体中的电子与乙腈团簇碰撞电离产生的 ,而CH3 CHCN+ (CH3 CN) n 是由乙腈团簇离子内的离子 分子反应生成的 .     

Spectroscopy of nickel chloride: Identification of the [15.0] Π3/2 and [15.0] Δ5/2 states

Vibrational bands belonging to the [15.0] ²Δ_5/2-A²Δ_5/2, [15.0] ²Δ_5/2-X²Π_3/2, and [15.0] ²Π_3/2-X²Π_3/2 electronic transitions of NiCl have been observed in the 14 000-16 000 cm⁻¹ region. The [15.0] ²Δ_5/2 and [15.0] ²Π_3/2 states are identified for the first time. The observed bands have been recorded at high spectral resolution using several techniques, which include intracavity laser spectroscopy (ILS), Fourier transform emission spectroscopy (FTS), and laser induced fluorescence (LIF) spectroscopy. For the ILS absorption spectra, NiCl molecules were produced in a nickel hollow cathode operated with a small amount of CCl₄. For the FTS emission spectra, excited NiCl molecules were produced in a King-type carbon tube furnace loaded with NiCl₂ and heated to 1600 °C. In the LIF work, NiCl molecules were produced by reacting laser-ablated nickel with PCl₃ seeded in argon. Detailed analysis of rotational transition lines indicates that the observed [15.0] ²Δ_5/2 and [15.0] ²Π_3/2 states are only separated by 10 cm⁻¹ and are interacting with each other. Molecular constants for these newly observed electronic states are reported.     

Theoretical analysis on phase-locking properties of a laser diode array facing an external cavity

External coupling model has been used to describe the output field of a laser diode array (LDA) phase-locked with an external cavity. The analytical solution for the coupling matrix equation of the phase-locked system has been obtained. The dependencies of the threshold gain, g_j of the system mode on the residue reflection of the front facet, r_f and round trip external cavity lengths, L have been discussed. The working lengths of the external cavity for stably phase-locking the LDA of different residual reflectivities have been calculated.     

用激光驱动冲击波测量高压状态方程的初步实验

 本文扼要介绍了以激光状态方程实验为目的而开展的铝靶烧蚀参数测量和激光冲击波实验，报道了这些实验的结果。     

激光聚变主放大器能源系统述评

 评述了激光聚变主放大器能源系统的演变过程。在简要评述传统能源系统的基础上，重点指出目前正朝向建立大型的能源组件实现模块化的方向发展，以减少系统元件数目，降低造价。结合NIF和神光Ⅲ原型能源模块的设计思路，述评了减少元件数目、降低造价、建造大型储能模块，以及采用大容量转换开关所带来的技术挑战和解决办法。同时指出开展能源单元技术(包括性能、风险、价格)研究是十分必要的。     

Fine structure in the time of flight distribution of C2 in laser produced plasma from graphite

Time resolved optical emission spectroscopy is employed to study the expansion dynamics of C₂ species in a graphite plasma produced during the Nd : YAG ablation. At low laser fluences a single peak distribution with low kinetic energy is observed. At higher fluences a twin peak distribution is found. It has been noted that these double peak time of flight distribution splits into a triple peak structure at distances ≥17mm from the target surface. The reason for the occurrence of multiple peak is due to different formation mechanisms of C₂ species.     

多孔硅激光染料镶嵌膜的荧光光谱研究

本文对以多孔硅为载体，镶嵌激光染料形成复合膜的光致发光进行了研究，比较了镶嵌膜与其他不同状态下染料发光的差异，发现镶嵌染料荧光光谱线型较其他状态下明显趋于对称，同时考察了衬底情况的改变对镶嵌膜发光的影响。通过对实验结果的分析指出，这种硅基镶嵌膜中的染料的发光主要来自单体的荧光发射。     

Experiment on Gamma Ray Generation by Laser Compton Scattering

A gamma ray generation facility was developed through laser Compton scattering on an electron beam storage ring, for the purpose of researching nuclear transmutation. Theoretical analysis on gamma ray yield and energy spectrum was performed, as well as EGS4 simulation code was employed to simulate the interaction of gamma ray and Ge detector. The acquired experimental results are in agreement with theory.     

迈向21世纪的舰用光电设备

综述当前舰用光电设备的研制特点和发展趋势。介绍这种设备的应用和研制状况。