大气压氦氩混合气体介质阻挡放电电学和光谱特性研究

以聚对苯二甲酸乙二醇酯作为介质,在大气压下产生氦氩混合气体放电等离子体。利用电压电流探头、数字示波器和数码相机研究了聚对苯二甲酸乙二醇酯介质阻挡氦氩混合气体放电的电学特性和发光特性。发现随氩气含量增加,每半个电压周期出现一个或多个电流脉冲,放电由均匀放电转变为斑图放电。利用衍射光栅和CCD探测器组成的光谱系统测量了氩原子谱线（696.54, 763.13, 772.09, 811.17和911.81 nm）光谱强度。研究了氩气含量、峰值电压对氩原子谱线光谱强度的影响。实验结果表明：在峰值电压较低时,上述五条氩原子谱线光谱强度随氩气含量的增加均呈现先增强-后减弱-再增强的变化规律;在峰值电压较高时,波长为696.54, 763.13和772.09 nm三条谱线光谱强度增强,波长为811.17和911.81 nm谱线光谱强度减弱。上述情况表明：在低峰值电压下,上述五条氩原子谱线光谱强度的变化规律是由于在放电过程中放电模式发生了变化;而在髙峰值电压下,五条谱线强度变化与气体激发机制有关。在氩气含量低于30%或高于80%时,氩原子谱线光谱强度随峰值电压的增加先保持不变,再增强到稳定值;在氩气含量介于30%～80%之间时,氩原子谱线光谱强度随峰值电压的增加也呈现先增强-后减弱-再增强的变化规律;利用玻尔兹曼图形法计算了氩原子放电的电子激发温度,得到了不同峰值电压下电子激发温度随氦气/氩气比例变化的规律：高峰值电压下电子激发温度明显高于低峰值电压下电子激发温度;电子激发温度随氩气含量增加而减小。出现上述变化规律的原因主要是由于电子与氦原子碰撞截面小,电子与氩原子碰撞截面大,而氦气扩散系数大于氩气扩散系数。     

离子液体对氩气介质阻挡放电光谱的影响

采用自行设计的介质阻挡放电反应器,以氩气和离子液体为放电介质,实现大气压下稳定的气(等离子体)-液(离子液体)等离子体放电,并运用光谱法在线诊断氩等离子体光谱。考察了不同咪唑基离子液体以及放电参数对大气压氩气介质阻挡放电光谱的影响。结果表明,离子液体的引入降低了氩气放电光谱的强度,谱峰强度与离子液体阳离子咪唑环上的碳链长度有关,且随碳链长度增加,谱峰强度降低;同时阴离子结构对称性低的离子液体,谱峰强度较低。加入离子液体后氩谱随放电电压及放电频率变化均呈现峰值变化。     

Measurement of the argon-gas-induced broadening and line shifting of the barium Rydberg level 6s24d 1D2 by two-photon resonant nondegenerate four-wave mixing

We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state to the obser-vation of the broadening and shifting of the barium Rydberg level 6s24d 1^D2 by collision with argon. The collision broadening and shifting cross sections are measured. This technique is purely optical, and can investigate the pressure dependence of the transverse relaxation rate-P21 between the Rydberg state and an intermediate state, as well as the transverse relaxation rate F20 between the Rydberg state and the ground state.     

氩气退火对氢掺杂AZO薄膜电学性能的影响

采用射频磁控溅射法,在石英玻璃衬底上制备出了性能良好的H掺杂AZO透明导电薄膜,通过XRD、Hall、UV-Vis等测试手段,研究了氩气气氛中退火温度对薄膜电学热稳定性的影响。实验结果显示,随着退火温度的升高,薄膜中载流子的浓度和迁移率下降。分析认为,这与薄膜中氢的逸出密切相关。     

Low-energy structure in the ionization of argon: Comparison of experiment with theory

The above-threshold ionization of argon in an intense 70-fs,400-nm linearly polarized laser pulse has been investigated by the velocity map imaging techniques,combined with an attosecond-resolution quantum wave packet dynamics method.There is a quantitative agreement in all dominant features between the experiment and the theory.Moreover,a peak-splitting phenomenon in the first energy peak has been observed at high pulse intensity.Further,through the theoretical analysis,an ac Stark splitting with evident resonant and nonresonant ionization pathways has been found to be the physical reason for the experimental observations.     

氩气对乙炔预混气爆轰不稳定性的影响及量化分析

为定量研究氩气对预混气爆轰不稳定性的影响,在管径为50.8、63.5 mm的管道内对未稀释及氩气稀释(氩气的体积分数为50%、70%、85%)的C₂H₂-O₂预混气进行了实验研究和量化分析,通过烟膜轨迹获得了不同初始压力下各种预混气的爆轰结构。对烟膜图像进行数字化处理,得到了氩气稀释下C₂H₂-O₂预混气爆轰轨迹的不规则度表征:轨迹间距的柱状图、标准差曲线、自相关函数。结果表明:随着氩气体积分数的升高,三波点轨迹愈加规则,不稳定性在爆轰自持传播过程中逐渐失去主导作用。稀释后预混气爆轰轨迹间距的柱状图和自相关函数的峰值和分布离散情况基本一致,与标准差分布一致。C₂H₂-O₂-85%Ar、C₂H₂-O₂-70%Ar、C₂H₂-O₂预混气的柱状图主胞格尺寸占比分别为33%、23%、20%,标准差分别为2.66~6.60 mm、5.37~10.96 mm、27.63~36.67 mm,自相关函数的第1个最高峰值分别高于其他峰值1/3倍、1/6倍、1/7倍。通过分析标准差数据,拟合得到氩气的体积分数与不稳定度的多项式函数,为选取不稳定度和氩气稀释浓度提供了依据。     

Growth Kinetics of Silicon Carbide Film Prepared by Heating Polystyrene/Si（111）

SiC films were prepared by heating polystyrene/Si（111） in normal pressure argon atmosphere at different temperatures. The films were investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared absorption measurements. The thicknesses of SiC films were calculated from FTIR spectra. The growth kinetics of the growth process of SiC films were investigated as well. The thicknesses of the SiC films grown for 1 h with increasing growth temperatures have different trends in the three temperature ranges： increasing slowly （1200-1250 ℃）, increasing quickly （1250- 12.70 ℃）, and decreasing （1270-1300 ℃）. The apparent activation energies of the growth process of SiC films in the three ranges were calculated to be 122.5,522.5, and -127.5 J/mol respectively. Mechanisms of the different growth processes were discussed. The relation between film thicknesses and growth temperatures indicated that the growth process was a 2D mechanism in the first range and 3D mechanism in the second range. In the third range, the thicknesses of SiC films were decreased by the volatility of Si and C atoms.     

真空熔融气相色谱法测定固体中痕量氩气的研究

建立了用气相色谱法测定固体内部痕量惰性气体的新方法.有效地解决了处于低真空状态待测气样的给样问题,优化了样品气体的纯化条件.用多种基准物质绘制了不同柱长的校正曲线,证明了新方法的可靠性.     

Experimental study on multiphoton ionization of Ar with high intensity short laser pulses

<正>We present high resolution photoelectron energy spectra from multiphoton ionization(MPI) of Ar subject to laser pulses with wavelength of 400 nm,pulse duration of 35 fs,and maximum intensity of 5×10~(13) W/cm~2.Ionizations into Ar~+ ~2P_(3/2) and ~2P_(1/2) channels are observed and distinct resonance structures are found in both ionization channels.The intensity dependence of the resonance structures is explained in terms of the mechanism of Freeman resonance,i.e.,transient resonances of alternating current (AC) Stark-shifted Rydberg states at specific intensities within the laser pulse.     

利用混合载气提高COIL化学效率

 为进一步提高氧碘化学激光器效率,提出一种不改变激光器结构,仅变换主副载气的方法。在增益区长度为11.7 cm的激光器上进行实验,以N₂, Ar和CO₂做为氧碘化学激光器的主载气或副载气,对激光器的输出功率和化学效率进行了研究。实验结果表明,平均分子质量改变对主副气流的混合是有利的,因而可以提高激光器的输出效率。当N₂为主载气,Ar为副载气时,激光器输出功率和化学效率最高,分别达到3.09 kW,30.2%。