H对HF泛频激光振转能级粒子数分布的影响

基于多体展式方法所导出的HHF体系的分析势能函数,用准经典的MonteCarlo轨迹法研究了H+HF(v′,J′)→H+HF(v″,J″)振转非弹性碰撞过程。结果表明:H原子对HF在低能和高能范围对高J转动能级有驰豫作用,对HF的振动能级的粒子分布有一定影响     

Theoretical performance of an HF chemical CW laser

A quantitative analysis of an HF cw chemical laser is presented that includes the influence of stimulated emission on the reacting medium. The numerically determined solutions encompass one-dimensional fluid mechanics, chemical kinetics, radiative de-excitation, and their mutual interaction. A comprehensive parametric study examines the effects due to changed plenum conditions, mixture ratios and cavity parameters. Best efficiency is obtained when the pumping is by the F + H₂ reaction. Pumping by the chain reaction sequence F + H₂ → HF(υ ≤ 3) + H and H + F₂ → HF(υ ≤ 6) + F results in substantially lower efficiencies due to increased HF-HF vibration-translation deactivation. Detailed discussions are presented of (1) vibration-vibration and vibration-translation energy exchange, (2) chemical efficiency, (3) mechanisms that cause lasing termination, and (4) cavity operation with a selective grating.     

氟化氢泛频化学激光器高超音速低温喷管研究

 通过建立一套氟化氢泛频化学激光器实验系统，介绍了一种新型高超音速低温喷管的结构及其实验参数设置方法；对喷管性能进行了测试，并将实验结果同数值模拟结果进行对比，找出了改善喷管性能的方法。由该喷管构成的激光系统已顺利出光。     

氟化氢泛频化学激光器高超音速低温喷管研究

通过建立一套氟化氢泛频化学激光器实验系统,介绍了一种新型高超音速低温喷管的结构及其实验参数设置方法;对喷管性能进行了测试,并将实验结果同数值模拟结果进行对比,找出了改善喷管性能的方法。由该喷管构成的激光系统已顺利出光。     

脉冲HF化学激光体系中的放电模式分析

采用面阵滑闪火花预电离诱导的平行板放电结构,研究了SF6-C2H6混合气体中的脉冲放电模式,确认了不同放电条件下存在自持体放电(SSVD)和电弧放电两种模式,且两种模式可以互相转化.SSVD模式放电电流波形主要由电容电压和气压决定,气体混合比和储能电容值对其影响很小.SSVD电流峰值随电容电压增加基本线性增加,随气压增...     

Lasing from an electron-beam-excited nonchain HF laser

The lasing parameters of a nonchain chemical HF laser (an active volume of 20 l) excited by a fast electron beam are studied at different energies delivered to the gas. It is shown that the laser operates efficiently when the energy deposited is below 30 J/l. Above specific excitation energies of 60–70 J/l, both the lasing efficiency and the laser output decrease.     

超音速氮稀释连续波HF化学激光器小信号增益测量

以氮为稀释剂的电激励连续波HF/DF化学激光器可以使用低温吸附泵代替传统的机械真空泵和洗消装置,大幅度降低激光器的系统体积和重量。使用小信号增益测量系统对某超音速氮稀释电激励连续波HF化学激光器的增益分布进行了测量。得到了在4种不同激光功率下P1(4),P1(6), P2(4)～P2(6)谱线的增益系数分布曲线。测得P2(4)为最强增益谱线,最大值为0.1 cm-1;最强增益位置与最佳光轴位置相符;超音速气流使增益区延伸达2.5 cm。     

N2对HF泛频激光振转能级粒子数分布的影响

基于多体展式方法所导出的N2HF的分析势能函数,用准经典的Monte Carlo轨迹法研究了N2HF(v′,J′)→N2+HF(v″,J″)振转非弹性碰撞过程.结果指出:N2对HF的振动能级的粒子分布影响较大,在较低相对平动能下,对HF转动能级有弛豫作用.     

Nuclear rotational population patterns in heavy-ion scattering and transfer reactions

A model of²³⁹Pu with decoupled neutron is used for theoretical calculations of rotational population patterns in heavy ion inelastic scattering and one-neutron transfer reactions. The system treated is⁹⁰Zr on²³⁹Pu at the near-barrier energy of 500 MeV and backscattering angles of 180° and 140°. The influence of the complex nuclear optical potential is seen to be very strong, and the Nilsson wave function of the odd neutron produces a distinctive pattern in the transfer reaction.     

电激励连续波HF/DF选线化学激光器光轴的选择

在一单放电管电激励连续波HF/DF化学激光器平台上,利用一级振荡、一级输出的光栅选线色散腔结构,分别在H2喷注孔平面下游0.5 mm和2.0 mm两个位置处测试了此激光器的选线性能。谱线指认的结果证实,即使在mm级的流场方向增益长度范围内,选线激光器要获得宽的谱线覆盖范围并优化各支谱线的功率谱分布,光轴到氢气喷注孔平面的距离是一个重要的调节参量,随着此距离的增大,高振动态之间的跃迁越来越弱,而低振动态之间的跃迁则越来越强。     

电激励连续波HF/DF选线化学激光器光轴的选择

 在一单放电管电激励连续波HF/DF化学激光器平台上,利用一级振荡、一级输出的光栅选线色散腔结构,分别在H2喷注孔平面下游0.5 mm和2.0 mm两个位置处测试了此激光器的选线性能。谱线指认的结果证实,即使在mm级的流场方向增益长度范围内,选线激光器要获得宽的谱线覆盖范围并优化各支谱线的功率谱分布,光轴到氢气喷注孔平面的距离是一个重要的调节参量,随着此距离的增大,高振动态之间的跃迁越来越弱,而低振动态之间的跃迁则越来越强。     

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。     

Observation of laser speckle effects and nonclassical kinetics in an elementary chemical reaction

An experimental demonstration is provided for memory-based, nonclassical reaction kinetics in a homogeneous system with an elementary reaction, A+B-->C. A new reaction-kinetics regime is observed which is a direct consequence of speckles in the laser beam. However, in spite of the nonrandom, speckled initial distribution of reactant B, the long-time regime gives the first experimental demonstration of the asymptotic self-segregation ("Zeldovich") effect. Monte Carlo simulation results are consistent with the experiments.     

Transfer of rotational population in CO by IR laser double resonance

A double resonance experiment on CO using two CO lasers (pump on v = 1 → 0, probe on v = 2 → 1) is described. Molecular diffusion has to be considered to reduce the data. The total rotational relaxation rate constant for J = 10 is found to be 1.25 ± 0.15 s^-1 torr^-1. Population transfer seems to proceed for $\text{2}\text{3}$ by |ΔJ| = 1 and for $\text{1}\text{3}\text{by |ΔJ| =2}$.     

Spectral composition of radiation of supersonic CW chemical lasers: An HF laser

The spectral characteristics of radiation generated by supersonic cw HF lasers are experimentally investigated at different basic operating parameters. It is demonstrated that the emission spectrum substantially depends on both the degree of dilution of a fuel mixture with helium in a combustion chamber of the atomic-fluorine generator and the chemical composition of an active medium. The range of variations in the secondary fuel (hydrogen) excess factor in which the lines weakly absorbed by the atmosphere are characterized by the largest fraction of the power of generated radiation is determined.     

Observation of rotational energy transfer in iodine by two-photon time delayed spectroscopy

The temporal evolution for individual rovibrational levels of the B state of the iodine molecule is observed by two-photon delayed spectroscopy. In particular the rotational energy transfer (RET) process due to collisions of the molecules in the B state with molecules in the ground state is studied. Thermal averaged rate constants for pairs of rotational levels of the v=27 vibrational state are measured. The results are discussed in terms of the dynamics of the collision process and numerical fits to the most important parametric fitting laws for RET are presented.     

连续波氟化氘/氟化氢化学激光器TRIP技术混合机理

 采用CLNST引入的扰流气注入技术对连续波氟化氘/氟化氢化学激光器进行数值模拟研究。模拟其3维流场有化学反应,但不考虑激射的情况。计算结果显示:加入扰流气后,平行注入的主副气流混合增强明显,气流混合速度明显加快,在喷管出口平面5 mm处即扩散至副喷管中心线位置,且小信号增益系数值明显增强。分析了流场结构得出:扰流气增强气流混合的主要方式在于使反应界面拉伸和扭曲,同时观察到有弱漩涡产生,但沿气流方向较快耗散掉,对流场影响较小。     

Coherent population transfer with chirped few-cycle laser pulses in an excited-doublet four-level system

The behavior of population transfer in an excited-doublet four-level system driven by linear polarized few-cycle ultrashort laser pulses is investigated numerically. It is shown that almost complete population transfer can be achieved even when the adiabatic criterion is not fulfilled. Moreover, the robustness of this scheme in terms of the Rabi frequencies and chirp rates of the pulses is explored.     

连续波氟化氘/氟化氢化学激光器TRIP技术混合机理

采用CLNST引入的扰流气注入技术对连续波氟化氘/氟化氢化学激光器进行数值模拟研究。模拟其3维流场有化学反应,但不考虑激射的情况。计算结果显示:加入扰流气后,平行注入的主副气流混合增强明显,气流混合速度明显加快,在喷管出口平面5 mm处即扩散至副喷管中心线位置,且小信号增益系数值明显增强。分析了流场结构得出:扰流气增强气流混合的主要方式在于使反应界面拉伸和扭曲,同时观察到有弱漩涡产生,但沿气流方向较快耗散掉,对流场影响较小。