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51.
General expressions used for transforming raw laser-induced fluorescence (LIF) intensity into the population and alignment parameters of a symmetric top molecule are derived by employing the density matrix approach. The molecular population and alignment are described by molecular state multipoles. The results are presented for a general excitation-detection geometry and then applied to some special geometries. In general cases, the LIF intensity is a complex function of the initial molecular state multipoles, the dynamic factors and the excitation-detection geometrical factors. It contains a population and 14 alignment multipoles. How to extract all initial state multipoles from the rotationally unresolved emission LIF intensity is discussed in detail.  相似文献   
52.
提出内积的溶液浓度测定方法。该方法计算已知浓度溶液透光率曲线与0号溶液(浓度最低的溶液)透光率曲线的内积ρ,确定溶液的ρ-C曲线,然后测定未知溶液的透光率曲线,计算其与0号溶液透光率曲线的内积,并利用已建立好的ρ-C曲线进行插值以估计溶液浓度。由于该方法利用了透光率曲线的全部信息,因此对溶液浓度的估计精度较高。对K2Cr2O7溶液浓度的测定实验结果表明,该方法对溶液浓度的估计相对误差小于1.00%。  相似文献   
53.
The study of wave propagation in periodic systems is at the frontiers of physics, from fluids to condensed matter physics, and from photonic crystals to Bose-Einstein condensates. In optics, a typical example of periodic system is a closely-spaced waveguide array, in which collective behavior of wave propagation exhibits many intriguing phenomena that have no counterpart in homogeneous media. Even in a linear waveguide array, the diffraction property of a light beam changes due to evanescent coupling between nearby waveguide sites, leading to normal and anomalous discrete diffraction. In a nonlinear waveguide array, a balance between diffraction and self-action gives rise to novel localized states such as spatial “discrete solitons” in the semi-infinite (or total-internal-reflection) gap or spatial “gap solitons” in the Bragg reflection gaps. Recently, in a series of experiments, we have “fabricated” closely-spaced waveguide arrays (photonic lattices) by optical induction. Such photonic structures have attracted great interest due to their novel physics, link to photonic crystals, as well as potential applications in optical switching and navigation. In this review article, we present a brief overview on our experimental demonstrations of a number of novel spatial soliton phenomena in light-induced photonic bandgap structures, including self-trapping of fundamental discrete solitons and more sophisticated lattice gap solitons. Much of our work has direct impact on the study of similar discrete phenomena in systems beyond optics, including sound waves, water waves, and matter waves (Bose-Einstein condensates) propagating in periodic potentials.   相似文献   
54.
A new stacking method via variation ofsubstrate temperature in rfmagnetron sputter is used to fabricate polycrystalline/polycrystalline Ba0.5Sr0.5TiO3 thin films with higher dielectric constant, higher breakdown strength and lower leakage current densities than those prepared by a conventionM deposition method. The improved figure of merit G (ε0εrEb) of the Ba0.5Sr0.5TiO3 thin films implies that they are a feasible insulation layer for thin film electroluminescent devices.  相似文献   
55.
交联粘土是一类新的具有规则孔结构的大孔分子筛,对其酸性及孔结构的研究已有报道。本文报道镍同晶置换T—O—T片八面体层中的铝,并用丙氨基三乙氧基硅烷水解物与其交联制得PNiSMM,再浸上Pd后考察Pd-NiSMM和Pd-PNiSMM对正己烷的加氢异构性能。  相似文献   
56.
A novel QNDT (quantitative non-destructive testing) method is developed that is combined with a phase-shifting shearing speckle and thermograph, and, it aims at the detection of faults such as cracks, voids, delamination and weak areas. The technique is immune to ambient noise and is suitable for measuring the in situ environment. Some different depth defects that would produce deformation differing from other positions could be found with shearing speckle when the sample is loaded, however, a thermograph based on the thermal resistance effect of a defect can detect only those varisized defects embedded deeply in the composite structure by measuring the surface temperature distribution. The resolution is examined for artificial delaminated defects in carbon-fiber composite structures using a phase-shifting shearing speckle and thermograph. The experimental results have demonstrated that the technique is effective for revealing defects in composite structures.  相似文献   
57.
推广的Painlevé展开及KdV方程的非标准截断解   总被引:19,自引:3,他引:16       下载免费PDF全文
楼森岳 《物理学报》1998,47(12):1937-1945
利用奇性流形的任意性,选用不同的展开函数及非标准截断展开于KdV方程,得到了许多用复杂隐函数表示的精确解. 关键词:  相似文献   
58.
导数光谱法测定污水中十二烷基苯磺酸钠   总被引:2,自引:0,他引:2  
本文介绍了用导数分光光度法直接定量分析污水中十二烷基苯磺酸钠的方法。本法消除了混浊背景干扰,操作简便快速。应用于实际污水样品的分析,获得了良好的结果,十二烷基苯磺酸钠的校准曲线线性范围为0-82mg/L。  相似文献   
59.
Generationof2-10nsExcimerLaserPulsebyOpticalSynchronizingWave-clippingXIANGShiqing;LOUQihong;DONGJingxing;MANGYanping;WEIYunr...  相似文献   
60.
分析了双传声器自适应零限波束形成语音增强算法对传声器不一致和本底噪声的鲁棒性。结果表明:信干比越高,算法对传声器不一致的鲁棒性越差;当信干比很低时,算法对相位不一致是鲁棒的。幅度不一致会降低算法对干扰的抑制能力,但引起的目标信号失真很小。相对于传声器不一致,本底噪声对算法性能的影响较小。对自适应滤波器权值加约束和对传声器做校准可以提高算法性能。  相似文献   
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