非链式化学HF(DF)激光器工作气体中电子分离的非稳定性和气体放电等离子体的自组织现象(英文)

报道了放电引发的非链式HF(DF)激光器中的激活介质由电子碰撞负离子分离引起的电离非稳定性。这种非稳性出现在电极空间分离、脉冲CO2激光加热的基于SF6的混合气体的大体积放电中。实验研究了自引发体放电过程中由激光加热引起的放电等离子体的自组织现象以及由此在放电间隙的大部分区域形成的准周期等离子体结构。重点分析了等离子体结构随气体温度和注入能量的变化,讨论了等离子体自组织对电子碰撞分离不稳定性所产生的影响,解释了混合气体中由于电子碰撞使负离子消失导致的单等离子体通道移动的产生机理。     

非链式HF/DF激光器的研究进展

HF/DF激光器是中红外波段能提供最高能量输出的激光光源,也是中红外波段应用非常广泛的相干光源。本文介绍了近几年国内外关于非链式HF/DF激光器的研究进展及其成果应用,分析了非链式HF/DF激光器在应用方面的优缺点,总结了实现非链式HF/DF激光输出的关键技术和存在的问题,指出了该技术的未来发展方向。     

放电引发的非链式高功率重复频率HF/DF激光器

高功率重频HF/DF激光因其具有的波长和功率优势成为当前中红外激光技术发展的热点之一。介绍了利用紫外预电离横向放电结构和工作气体循环系统建立的放电引发高功率重频HF/DF激光装置。在对激光工作介质SF6/C2H6混合气体放电特性和激光输出特性研究的基础上,开展了强电负性气体的重频均匀体放电技术和气体快速循环置换技术研究,解决了泵浦源重频放电能量在气体介质中的有效沉积和提取问题,实现了激光器50 Hz的重频稳定运行和能量稳定输出,HF激光的平均功率达到28 W,脉宽100 ns,峰值功率5.6 MW。     

非链式脉冲DF激光器的关键技术（英文）

基于化学反应的非链式脉冲DF激光器是产生3.5～4.1μm波段的有效相干辐射光源,具有存储能量水平高等优点。这些优点使得该激光器倍受中红外领域激光研究者的重视。为了更好地提高非链式脉冲DF激光器的输出性能,研制高能量水平的DF激光器,本文详细介绍了自引发大体积放电技术、混合气体配比技术、循环冷却技术等DF激光器关键技术,重点介绍了自引发大体积放电技术。这几种技术将为研制高性能DF激光器提供理论指导。     

放电引发的非链式高功率重复频率HF/DF激光器

高功率重频HF/DF激光因其具有的波长和功率优势成为当前中红外激光技术发展的热点之一。介绍了利用紫外预电离横向放电结构和工作气体循环系统建立的放电引发高功率重频HF/DF激光装置。在对激光工作介质SF6/C2H6混合气体放电特性和激光输出特性研究的基础上,开展了强电负性气体的重频均匀体放电技术和气体快速循环置换技术研究,解决了泵浦源重频放电能量在气体介质中的有效沉积和提取问题,实现了激光器50Hz的重频稳定运行和能量稳定输出,HF激光的平均功率达到28W,脉宽100ns,峰值功率5.6 MW。     

紫外预电离放电引发的非链式脉冲DF激光器

采用紫外预电离的横向放电方式和稳定光学谐振腔,使用无毒无腐蚀性的六氟化硫(SF6)和氘气(D2)作为工作物质,研究了工作气体配比、总气压对放电引发非链式脉冲氟化氘(DF)激光器输出能量的影响。实验发现SF6与D2的最佳比例为10:1,最佳总气压为10.5 kPa。使用DF激光谱线分析仪对激光输出谱线进行了测量,得到了17条P支跃迁谱线,激光能量集中在3.876μm附近的几条谱线。利用烧蚀光斑的方法测得输出激光束水平方向、垂直方向的发散角均为1 mrad。在最佳工作条件下,充电电压为39 kV时,激光单脉冲输出能量达到最大值3.58 J,此时激光脉冲宽度为215 ns,峰值功率为16.65 MW,电光转换效率为2.08%。     

非链式HF激光器SF6气体介质放电特性

采用放电图像拍摄和放电波形测量两种方法研究了放电激励HF激光工作介质SF6气体的放电特性。实验结果表明：SF6气体放电可以分为主放电、剩余电压维持和电弧放电3个阶段。主放电阶段为均匀体放电,电容储能大部分在此阶段沉积于放电等离子体中;剩余电压维持阶段无明显放电;在电弧放电阶段激光器以电弧形式消耗剩余储能。通过对放电波形的分析,获得剩余电压及主放电阶段能量沉积效率随充电电压的变化规律。随着充电电压提高,剩余电压下降,沉积效率逐渐提高。沉积效率最大值对应于主放电与电弧放电相接的时刻。     

非链式脉冲DF激光器的关键技术(英文)

基于化学反应的非链式脉冲DF激光器是产生3.5～4.1μm波段的有效相干辐射光源,具有存储能量水平高等优点。这些优点使得该激光器倍受中红外领域激光研究者的重视。为了更好地提高非链式脉冲DF激光器的输出性能,研制高能量水平的DF激光器,本文详细介绍了自引发大体积放电技术、混合气体配比技术、循环冷却技术等DF激光器关键技术,重点介绍了自引发大体积放电技术。这几种技术将为研制高性能DF激光器提供理论指导。     

用于泵浦非链式HF/DF化学激光器的重复频率电子束发生器研究

 正在研究的1Hz重复频率电子束泵浦HF/DF化学激光器，预期产生的电子束能量为0.5MeV、束流强度为100kA、束流脉冲宽度为100ns。在该系统设计中，使用了一个脉冲变压器来对脉冲成形水线进行双共振充电。脉冲变压器的初级、次级电感与互感分别为331nH，26.5μH与1.9μH。脉冲成形线的电容、电感与阻抗分别为8.15nF，300nH与6.2Ω。脉冲成形线在1MV的峰值充电电压下的击穿因子为0.3。在3.3%的能量转换效率条件下，预期可以产生的HF/DF激光脉冲能量为２50J以上。     

用于泵浦非链式HF/DF化学激光器的重复频率电子束发生器研究

正在研究的1Hz重复频率电子束泵浦HF/DF化学激光器,预期产生的电子束能量为0.5MeV、束流强度为100kA、束流脉冲宽度为100ns。在该系统设计中,使用了一个脉冲变压器来对脉冲成形水线进行双共振充电。脉冲变压器的初级、次级电感与互感分别为331nH,26.5μH与1.9μH。脉冲成形线的电容、电感与阻抗分别为8.15nF,300nH与6.2Ω。脉冲成形线在1MV的峰值充电电压下的击穿因子为0.3。在3.3%的能量转换效率条件下,预期可以产生的HF/DF激光脉冲能量为２50J以上。     

DF/HF化学激光器HYLTE喷管的副喷管质量流量系数

 对DF/HF化学激光器HYLTE喷管的副喷管质量流量进行了数值和理论计算，得出入口滞止压力在0.01~0.4MPa之间、喉道半高度在0.1~0.9mm之间的喷管的氘气，氢气和氦气质量流量系数，总结出质量流量系数随入口滞止压力和喉道高度的变化规律，并给出拟合公式，为副喷管的设计提供依据。     

HYLTE喷管流场混合性能的实验和数值模拟研究

 用激光诱导碘荧光的方法对高超音速低温喷管的混合性能进行了测量，并用CFD软件FLUENT模拟了喷管的流场。两种方法所得的结果吻合得较好，在所给的参数条件下，燃料穿过氧化剂流，后者先被前者压缩，然后稍有膨胀。两股气流充分混合的地方距喷管出口平面10mm左右。实验与模拟的主要差别在于两股气流相遇后，实验结果中气流方向变化不大，而在模拟结果中，气流方向改变为基本上与x轴平行。     

Spectroscopic investigation of the plasma of a high-current diffuse discharge in He/Ar/CF2Cl2(CCl4) mixtures

Survey emission spectra in the region of 190–600 nm and time and service-life characteristics of a transverse nanosecond discharge in He/Ar/CF₂Cl₂(CCl₄) mixtures at a pressure of 10–100 kPa are investigated. In the emission spectra, excited products of the decomposition of freons—C₂(A−X), CN(B−X), Cl ₂ ^* , C^*, Cl^*, and Cl^+*— and the emission of ArF at λ=193 nm are revealed. The emissions of Cl ₂ ^* at λ=258 nm and ArF at λ=193 nm were the most intense. The discharge in the He/Ar/CF₂Cl₂ mixture is a multiwave emission source with λ=258 nm Cl ₂ ^* 193 nm ArF, and probably, 175 nm Arcl. It is of interest for applications in UV-VUV-range pulse photometry. The duration of the emission on Cl ₂ ^* , ArF, ArI, ClI, and ClII transitions in the discharge in the Ar/CF₂Cl₂ mixture (P=10–20 kPa) was 200–300 nsec. With adding He and increasing pressure to 100 kPa the duration of the emission decreased by a factor of 1.5–2. The basic mechanisms of the formation of Cl₂, ArF, and CN(B) molecules in the transverse-discharge plasma are considered. Uzhgorod State University, 46, Pidgirna Str., Uzhgorod, 294000, Ukraine. Translated from Zhurnal. Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 241–246, March–April, 1999.     

Characteristic of a negative corona discharge in active media of Xe(6p−5d) and eximer lasers

The article contains results of a study of electric and optical characteristics of a negative corona discharge in a “needles-grid” electrode system in the mixtures He/Xe and He/Xe(Kr)/HCl, which are used in periodic pulsed electric-discharge Xe(6p−5d), XeCl, and KrCl lasers. The corona discharge was ignited in a multielectrode system whose length is commensurable with the length of the active medium of the lasers. Voltage-current characteristics, radiation spectra of the discharge plasma, and the dependences of the radiation intensity of atomic spectral lines and the band λ=308 nm of XeCl (B-X) on parameters of the corona discharge are studied. For the mixture He/Xe the corona discharge exists as a spatially homogeneous discharge that is intermediate between corona and glow discharges and is transformed into an anode streamer at higher charge voltages. Collisional purification of the 6p states of the Xe atom by helium was observed. In the mixture He/Xe/HCl the corona discharge is ignited in the form of individual generation zones and a dark external region and can be used in electric systems for pumping the active media of XeCl and KrCl lasers. Uzhgorod State University, 46, Pidgirna St., Uzhgorod, 294000, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 205–210, March–April, 1998.     

1.0 MeV电子辐照致VO_2(B)薄膜结构与光谱改变研究

本文以能量为1.0 MeV的电子束辐照VO2(B)薄膜,对电子辐照在薄膜中产生的缺陷进行了理论计算,同时使用X射线衍射仪、原子力显微镜、分光光度计对薄膜进行测试,分析了电子辐照对薄膜结构、形貌与紫外-可见光谱(280~880nm)的影响。结果显示:电子辐照可以在薄膜中引入点缺陷并产生退火效应,电子辐照使薄膜的表面晶粒细化,辐照后薄膜光谱的吸收峰位发生移动,其移动的最大位移达到21nm,辐照后薄膜的光学禁带宽度也有所增加。     

Theoretical Studies of the Electron Paramagnetic Resonance and Optical Spectral Data for Vanadium(IV) Ion in Yttrium Aluminum Garnet Crystal

Four spin-Hamiltonian parameters (g factors g _// and g _⊥ and hyperfine structure constants A _// and A _⊥) and two optical spectral band positions for vanadium(IV) (V⁴⁺) ion in the tetrahedral Al³⁺ site of yttrium aluminum garnet (Y₃Al₅O₁₂) crystals are calculated from the (third-order) perturbation theory method (PTM) and complete diagonalization (of energy matrix) method (CDM). Both methods are based on the cluster approach. The calculated results from both methods coincide and reasonably agree with the experimental values. The defect structure of V⁴⁺ center (which is different from the corresponding structure in the host crystal) in Y₃Al₅O₁₂ crystal is also obtained from the calculation.     

Cu1-xHxZr2(PO4)3中Cu2+的EPR谱和局域结构研究

本文采用Cu²⁺斜方对称电子顺磁共振（EPR）参量的高阶微扰公式计算了晶体Cu_1-xH_xZr₂（PO₄）₃中Cu²⁺的EPR参量（g因子和超精细结构常数A因子）．计算结果表明,晶体Cu_1-xH_xZr₂（PO₄）₃中[CuO₆]^10-基团的Cu-O键长分别为R_||≈0.241 nm,R_⊥≈0.215 nm,平面键角τ≈80.1°;由于对称性降低,中心金属离子基态²A_1g（θ）和²A_1g（ε）有一定程度混合,混合系数α≈0.995．所得EPR谱图的理论计算值与实验数据符合得很好．     

Additivity and non-additivity of dissociation energies in intermolecular interactions. Theoretical studies on (H2)n,n = 2-8, (CO2)n,n = 2-6 and (HF)n,n = 2-8

CCSD(T) and MP2 results using the aug-cc-pV5Z basis set are reported for chain, cyclic and other structures of the clusters (H₂)_n, n?=?2-8, (CO₂)_n, n?=?2-6 and (HF)_n, n?=?2-8. In chain-like structures of (H₂)_n and (CO₂)_n, with the bonding type of the dimer maintained, the dissociation energy D_e of the dimer doubles for the trimer, triples for the tetramer, and so on. Due to these systems being dominated by short-range forces, interactions are essentially restricted to neighbouring monomers. For other types of (H₂)_n and (CO₂)_n structures, the multipliers relative to the dimerisation energy can be much higher. Dissociation energies for the hexamers in S₆ symmetry of both H₂ (379?cm^?1) and CO₂ (4925?cm^?1) are over ten times the respective dimerisation energies. For the chain-like trimer of HF, however, D_e is in excess of double the dimer value. Mainly due to longer-range dipolar forces, the interactions reach beyond the neighbouring monomers. The interaction energy between HF monomers in chains follows an approximate R^?2 (R being the F–F distance) relationship, The calculated dissociation energies of the HF octamer are 15,985?cm^?1 (factor of 10.4) for the chain, and 21,003?cm^?1 (factor of 13.7) for the C_6h cyclic structure.