锡石的振动光谱与成因的研究

用因子群相关分析方法讨论了锡石晶格简正振动模式的数目、对称性和红外及拉曼规律,得出了四个红外活性振动频率及四个拉曼活性振动频率。并根据红外光谱的形状和强度,将锡石的红外光谱分成三种类型,即标准谱、变形谱和畸形谱,它们可以提供锡石晶体结构,成分和成因的信息。     

拉曼光谱偏振特性的研究

在研究拉曼光谱偏振特性的基础上，计算出四氯化碳(CCl4)样品各简正振动模式的退偏度，设计了测量拉曼光谱退偏度的实验方案，并得到理论和实验相吻合的结果。     

4-N-甲基苯乙烯砒啶盐衍生物振动超极化率的理论研究

在双谐振子近似下，利用耦合微扰Hartree-Fock方法计算了4-N-甲基苯乙烯砒啶盐衍生物分子的静态振动第一超极化率和红外与拉曼光谱，给出了对静态振动第一超极化率起主导贡献的两种简正振动模式. 研究发现，标题分子的静态振动第一超极化率都比较大，且与静态电子第一超极化率呈较好的线性关系. 首次提出了利用红外与拉曼光谱特征峰标识的振动模来估算振动第一超极化率大小的少模方法. 结果表明，少模方法用于估算振动第一超极化率的大小是可行的.     

Nd:LuVO_4晶体的拉曼光谱研究

采用不同的几何配置测量了Nd:LuVO4晶体的室温拉曼光谱,根据群论对称性分类计算了该晶体的红外和拉曼活性振动模并与实验结果做了比较,指认了测定的特征谱线。测量并分析了Nd:LuVO4晶体A1g全对称类的高温拉曼光谱,讨论了拉曼频移随温度变化的关系,认为晶体的热膨胀是引起拉曼频移变化的主要原因。     

低温相HI分子晶体振动光谱计算

本文用弹性力常数模型计算了低温相ＨＩ晶体的振动光谱。利用９个可调参数计算出３７个晶格模式和８个内部模式晶场分裂谱线频率，结果与实验值甚符合，同时结合群论分析对晶体拉曼和红外光谱进行了全面指认，计算还给出晶体中各类相互作用力参数。     

邻苯二甲酸酐分子振动光谱的实验和理论研究

分别在3500~100和3500~500cm-1范围内测量了邻苯二甲酸酐分子的拉曼和红外实验光谱,同时利用密度泛函理论中的B3LYP混合泛函方法和6-311G(d,p)基函数组,计算了该分子的平衡构型和振动频率,及其拉曼和红外光谱强度,结果表明:理论计算和实验结果较好的符合。最后采用简正振动分析方法得到了各振动模的能量分布,从而对该分子的振动频率归属做出了全面指认。     

基于密度泛函理论的尼克酸分子振动光谱分析

实验测量了尼克酸分子的拉曼和红外光谱,用B3LYP混合泛函和cc-PVDZ基组计算了尼克酸分子的平衡构型、振动频率、拉曼和红外强度。采用GAR2PED程序对尼克酸分子进行了简正振动分析,依据所得势能分布对尼克酸分子的振动频率进行了理论归属,弥补了以往文献缺少对其振动模式贡献进行定量研究的不足,提供了更多的振动光谱信息。     

亚已基硫脲分子的拉曼、红外光谱和简正振动分析

实验测量了亚乙基硫脲分子的拉曼和红外光谱, 用量子化学方法计算了分子的几何构型以及振动频率, 以实验频率为标准对分子内力场进行了标度, 采用简正振动分析方法得到了各振动频率的势能分布, 从而对亚乙基硫脲分子的振动频率归属做出了全面指认。     

一种新型硅基3C-SiC的生长方法及光谱学表征

采用LPCVD技术, 以CH4和H2混合气体为反应源气, 在n-Si（111）衬底上生长3C-SiC晶体薄膜。H2在反应过程中作为稀释气体和运输气体, CH4作为碳源, 硅源有衬底硅来提供。利用X射线衍射分析仪、场发射扫描电子显微镜、激光拉曼光谱和傅里叶变换红外光谱分别研究3C-SiC薄膜的晶相结构、表面形貌及其光谱性质。结果表明此生长方法可以成功的成长出3C-SiC薄膜。     

1,4-萘醌的太赫兹,远红外及低频拉曼光谱研究

本文对1,4-萘醌进行了太赫兹时域光谱,远红外吸收光谱及低频拉曼散射谱的测试研究。1,4-萘醌的太赫兹吸收光谱与远红外谱仪测得的光谱取得了在1.75 THz(58.3 cm-1)/1.63 THz(54.3 cm-1)等处吸收峰位基本相同、两者相互佐证和补充的结果。将太赫兹和远红外吸收谱与低频拉曼散射谱进行比较,表明两种选择机制不同的光谱在1.04,1.72和4.59 THz等处的峰位基本重合,结合群论的不可约表示理论分析,表明该样品在低频波段具有拉曼活性和红外活性的振动属性(A1、B1或B2)。采用Gaussi-an03软件的密度泛函理论B3LYP函数和6-311基组模拟单分子红外与拉曼光谱,结合实验分析,对部分分子基团或原子振转模式给与了指认。     

Squeezed State Caused by Inverse of Photon Creation Operator

Using the photon creation operator's eigenstate theory we derive the normally ordered expansion of inverse of the squeezed creation operator. It turns out that using this operator a kind of excitation on the squeezed vacuum states can be formed.     

Trajectories Joining Two Submanifolds under the Action of Gravitational and Electromagnetic Fields on Static Spacetimes

In this paper we present existence and multiplicity results for orthogonal trajectories joining two submanifolds under the action of gravitational and electromagnetic fields on static spacetimes. These trajectories are critical points of unbounded functionals and they can be found by using a variant of the saddle point theorem and the relative category theory.     

Solution for One-Dimensional Quantum Oscillator with Time-Dependent Frequency and Mass

Based on the generalized linear quantum transformation theory, we present a normal ordering evolution operator for onedimensional quant urn oscillator with time-dependent frequency and mass, then give the exact expression of the evolution matrix elements, wave function and expectation value of arbitrary observable.     

Investigation of long-range sound propagation in surface ducts

Understanding the effect of source-receiver geometry on sound propagation in surface ducts can improve the performance of near-surface sonar in deep water. The Lloyd-mirror and normal mode theories are used to analyze the features of surface-duct propagation in this paper. Firstly, according to the Lloyd-mirror theory, a shallow point source generates directional lobes, whose grazing angles are determined by the source depth and frequency. By assuming a part of the first lobe to be just trapped in the surface duct, a method to calculate the minimum cutoff frequency （MCF） is obtained. The presented method is source depth dependent and thus is helpful for determining the working depth for sonar. Secondly, it is found that under certain environments there exists a layer of low transmission loss （TL） in the surface duct, whose thickness is related to the source geometry and can be calculated by the Lloyd-mirror method. The receiver should be placed in this layer to minimize the TL. Finally, the arrival angle on a vertical linear array （VLA） in the surface duct is analyzed based on normal mode theory, which provides a priori knowledge of the beam direction of passive sonar.     

Fluctuation effects in spin diffusion measurements in liquid He

We have measured spin diffusion coefficients of liquid ³He at a frequency of 920 kHz by pulsed NMR. By analyzing our data in the framework of the Leggett–Rice theory we got a spin diffusion coefficient and a Leggett–Rice parameter =λωτ simultaneously at each temperature. On approaching the superfluid transition the spin diffusion coefficients showed a deviation from predictions of the Fermi liquid theory. The deviation at low pressure was larger than that at high pressure. This anomaly may be due to the effects of fluctuations of superfluidity which were recently observed in the viscosity measurement of liquid ³He.     

The Associative Algebras of Conformal Field Theory

Modulo the ideal generated by the derivative fields, the normal ordered product of holomorphic fields in two-dimensional conformal field theory yields a commutative and associative algebra. The zero mode algebra can be regarded as a deformation of the latter. Alternatively, it can be described as an associative quotient of the algebra given by a modified normal ordered product. We clarify the relation of these structures to Zhu's product and Zhu's algebra of the mathematical literature.     

2-巯基噻二唑的拉曼、红外光谱、DFT计算和简正振动分析

采用B3LYP混合泛函和6-311G基函数组,并对重原子和轻原子使用离散函数和极化函数,利用密度泛函理论计算了2-巯基噻二唑的分子振动频率。实验测量了2-巯基噻二唑分子的拉曼、红外光谱,以实验频率为标准对分子内力场进行了标度,采用简正振动分析方法得到了各振动模的势能分布,从而对该分子的振动频率归属做出了全面指认。     

Model‐independent structure factors from powder X‐ray diffraction: a novel approach

Under the experimental condition that all Bragg peaks in a powder X‐ray diffraction (PXRD) pattern have the same shape, one can readily obtain the Bragg intensities without fitting any parameters. This condition is fulfilled at the P02.1 beamline at PETRA III using the seventh harmonic from a 23 mm‐period undulator (60 keV) at a distance of 65 m. For grain sizes of the order of 1 µm, the Bragg peak shape in the PXRD is entirely determined by the diameter of the capillary containing the powder sample and the pixel size of the image plate detector, and consequently it is independent of the scattering angle. As an example, a diamond powder has been chosen and structure factors derived which are in accordance with those calculated from density functional theory methods of the WIEN2k package to within an accuracy that allows a detailed electron density analysis.     

局域模、简正模的李代数表示

本文介绍李代数的非简谐振子的表示。运用这样的表示可以方便地讨论局域模与简正模之关系及其半经典图象。     

An oscillation phenomenon of low frequency reverberation in the shallow water and its physical explanation

~~An oscillation phenomenon of low frequency reverberation in the shallow water and its physical explanation1 Zhang, R.. Jin. G. Normal-mode theory of average reverberation intensity in shallow water, Journal of Sound and Vibration, 1987 19(2):215-223 2. Ellis, D. D., A shallow-water normal-mode reverberation model, J. Acoust. Soc, Am., 1995, 97(5): 2804-2814. 3. McDaniel, S. T., Seafloor reverberation fluctuations, J. Acoust. Soc. Am., 1990, 88(3): 1530-1535. 4. Abraham, …