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131.
1 Introduction Spectroscopicresearchesoncollisionsbetweenexcitedatomscontributeagreatdealtoourunderstandingoninteratomicinteractionsandcollisionaldynamics .Thealkalimetalvaporsaresuitablechoicesforsuchpurposesbecauseoftheirstrongandsharpresonanceabso… 相似文献
132.
背景噪声对单分子光子统计的影响 总被引:4,自引:1,他引:3
我们利用HanburyBrown和Twiss探测方法来记录两个单光子计数器响应单分子源输出的每一个事件 ,直接计算触发式单分子光子源的Mandel参数Q。通过对触发式单分子源的Mandel参数QRS与含有相同平均光子数的具有Poisson分布的相干态的Mandel参数Qc进行比较来确定光子源统计分布特性。研究得到了一种计算触发式单光子源信噪比 (SBR)有效的方法。 相似文献
133.
Research on the distributed optical remote sensing of methane employing single laser source 总被引:2,自引:0,他引:2
A design and testing of a cost-effective distributed optical remote sensing methane system, which will help one to detect gas leaks from multi-coal face in mines simultaneously, is presented. The fundamentals of the remote detection are based on frequency-modulation spectroscopy (FMS) and harmonic detection. By utilizing fiber-optic splitting technique and reference-signal restoring circuit, the remote sensing system is feasible to employ single laser source to get multi-spot measurement in the near infrared region so that the system described here shows sufficient sensibility, considerably increased reliability and marketability over the presently available system. The minimum measurable path-integrated concentration is estimated to be about 423 ppb-m by experimentation. 相似文献
134.
研究聚合物薄膜纳米尺度的动力学特性对于高性能材料的制备具有重要的意义.本文利用尼罗红单分子作为光学探针吸附在聚丙烯酸甲酯(PMA)聚合物链上,研究该聚合物薄膜的动力学特性.通过单分子散焦宽场荧光成像显微镜技术测量了单分子随PMA聚合物链转动弛豫的三维再取向特性,当环境温度高于PMA的玻璃点温度19 K时,发现处于PMA聚合物薄膜中的单分子光学探针的转动态和非转动态的持续时间概率密度服从指数截止的幂律分布.研究结果表明该温度下PMA聚合物薄膜的纳米环境动力学仍存在空间和时间异构性. 相似文献
135.
Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical spectroscopy technique. This review presents the main recent developments in China regarding the implementation of LIBS for coal analysis. The paper mainly focuses on the progress of the past few years in the fundamentals, data pretreatment, calibration model, and experimental issues of LIBS and its application to coal analysis. Many important domestic studies focusing on coal quality analysis have been conducted. For example, a proposed novel hybrid quantification model can provide more reproducible quantitative analytical results; the model obtained the average absolute errors (AREs) of 0.42%, 0.05%, 0.07%, and 0.17% for carbon, hydrogen, volatiles, and ash, respectively, and a heat value of 0.07 MJ/kg. Atomic/ionic emission lines and molecular bands, such as CN and C2, have been employed to generate more accurate analysis results, achieving an ARE of 0.26% and a 0.16% limit of detection (LOD) for the prediction of unburned carbon in fly ashes. Both laboratory and on-line LIBS apparatuses have been developed for field application in coal-fired power plants. We consider that both the accuracy and the repeatability of the elemental and proximate analysis of coal have increased significantly and further efforts will be devoted to realizing large-scale commercialization of coal quality analyzer in China. 相似文献
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138.
PRECISE MEASUREMENT OF DENSITY-DEPENDENT SHIFT BY WAVELENGTH MODULATION REFLECTION SPECTROSCOPY
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The density dependence of the line shift of the cesium D2 line is studied with sub-Doppler selective reflection spectroscopy. By use of wavelength modulation and sixth-harmonics detection we observed the coefficient of the pressure-induced shift of the 6S1/2(F=4)→6P3/2(F'=3) hyperfine transition of the cesium D2 line Δδ/ρ=-0.9(5)×10-8cm3. In the limit ρ=0 a frequency shift about -3MHz remains, which may be attributed to long-range atom-surface interactions. The experimental results can be used in measurements of the local field-induced frequency shift at high atomic densities with sufficient accuracy. 相似文献
139.
实验使用Nd:YAG激光二倍频光泵浦LD751染料,发现在产生染料激的同时,有喇曼光谱产生,实验观察到了较强的反斯托克斯线,喇曼位移为104cm^-1。 相似文献
140.
A novel method of high-resolution spectroscopy of gases is proposed. The method is based on observing the optical behaviour of the vapour layer when the particles cross the light beam or collide with the cell walls. The atomic motion and electronic quenching on gas-solid interfaces are explored by numerical analysis. The periodicity of peak values of transmission spectra and its derivative spectra demonstrates a sub-Doppler structure corresponding to the resonant transitions. 相似文献