多元件谐振腔的等价腔

本文使用光学变换矩阵方法，分析了多元件谐振腔的等价腔问题。发展了等价腔的一些概念和方法，推出了在普遍情况下，等价腔各参量与原谐振腔各参量之间的解析关系，并得到了一组不变量；同时，还澄清了一些关于等价腔的错误看法和易混淆之处。     

富勒烯在SiO_2与SiO_2－TiO_2凝胶中的掺入及光谱特性研究

本工作以ＳｉＯ_２和ＳｉＯ_２－ＴｉＯ_２凝胶体系为基质，选择合适的溶剂，采用特定的溶胶一凝胶工艺，成功地将纯的Ｃ_（６０）和Ｃ_（６０）／Ｃ_（７０）混合物分别均匀掺入上述基质中．研究了吸收与荧光光谱特性．室温下观测到峰置位于６６０ｎｍ附近的较强荧光带．对上述光谱性质作了初步的解释．     

400GeV/c pp碰撞赝快度空间带电粒子数密度的研究

利用CERNNA27合作组提供的LEBC泡室照片,测量了400GeV/cpp碰撞产生的带电粒子多重数为4—24的赝快度分布.观察到在选择的赝快度窗口(Δη=0.5和0.1)内平均最大带电粒子数密度随带电粒子多重数线性增加的规律.最大带电粒子数密度的几率分布在n大时有加宽和变平坦的趋势.没有观察到最大粒子数密度反常高的事例.     

AD GALERKIN ANALYSIS FOR NONLINEAR PSEUDO—HYPERBOLIC EQUATIONS

AD(Alternating direction)Galerkin schemes for d-dimensional nonlinear pseudo-hyperbolic equations are studied.By using patch approximation technique,AD procedure is realized,and calculation,work is simplified.By using Galerkin approach,highly computational accuracy is kept.By using various priori estimate techniques for differential equations,difficulty coming form non-linearity is treated,and optimal H^1 and L^2 convergence prop-erties are demonstrated.Moreover,although all the existed AD Galerkin schemes using patch approximation are limited to have only one order accuracy in time increment,yet the schemes formulated in this paper have second order accuracy in it.This implies an essential advancement in AD Galerkin aualysis.     

On a proposed characterization of Schatten-class composition operators

For an analytic function which maps the open unit disc to itself, let be the operator of composition with on the Bergman space . It has been a longstanding problem to determine whether or not the membership of in the Schatten class , , is equivalent to the condition that the function has a finite integral with respect to the Möbius-invariant measure on . We show that the answer is negative when .

     

Structural and electrical properties of Au/Pt/Ti ohmic contacts to degenerated doped n-GaAs

The ohmic contact characteristics of Au/Pt/Ti on degenerated doped n-GaAs were evaluated. Structural and electrical properties were studied by means of X-ray diffraction (XRD), Auger Energy Spectrum (AES) and a HP4145B parameter analyzer. The structural analysis revealed a TiAs phase in the interface between metal multilayer and GaAs at higher annealing temperatures. Electrical measurement showed a minimum ohmic contact resistance of 3×10^-4 Ω cm². The dominant current mechanism was found to be thermionic emission with a barrier height of Φ_b, of 0.09 V by comparing the experimental data with different theoretical models. Received: 14 December 2001 / Accepted: 4 April 2002 / Published online: 22 November 2002 RID="*" ID="*"Corresponding author. Fax: +86-21/6226-4397, E-mail: zhoujian999@163.net     

Deposition of ZnO thin films on (100) γ-LiAlO2 substrate

Optical properties for ZnO thin films grown on (100) γ-LiAlO2 (LAO) substrate by pulsed laser deposition method were investigated. The c-axis oriented ZnO films were grown on (100) γ-LiAlO2 substrates at the substrate temperature of 550 C. The transmittance of the films was over 85%. Peaks attributed to excitons were shown in absorption spectra, which indicated that thin films had high crystallinity. Photoluminescence spectra with the maximum peak at 540 nm were observed at room temperature, which seemed to be ascribed to oxygen vacancy in the ZnO films caused by diffusion of Li from the substrates into the films during the deposition.     

Infrared spectra of carbon monoxide-hydrogen sulfide van der Waals complexes in the C-O stretching region

The CO-stretching vibration-rotation spectra of CO-H₂S, CO-D₂S, and CO-HDS complexes have been studied in the 2150 cm⁻¹ region using a supersonic slit-jet expansion and a tunable diode laser spectrometer. The spectra were analyzed with the help of very recent microwave pure rotational studies of the same complexes. Two bands were assigned for each of the symmetric hydrogen sulfide isotopes, corresponding to the two nuclear spin modifications, para and ortho. The band origins were blue shifted, relative to the free CO molecule, by about 3.8 cm⁻¹ for CO-H₂S and 4.3 cm⁻¹ for CO-D₂S. These are considerably smaller shifts than exhibited by the related CO-water complexes, indicating that the intermolecular forces in CO-H₂S are weaker and more isotropic.     

Investigation of the stability for inviscid compressible swirling flow between concentric cylinders

The temporal stability on inviscid compressible swirling flow between two concentric cylinders is investigated. First, a linearized differential equation is derived. Two stability criteria are derived for compressible swirling flow by an analytic method analogous to Ludwieg ’s method. A finite-difference numerical method is then used to solve the eigenvalue problem of this differential equation, to get temporal growth rate and to check these stabilitv criteria derived. Finally.The effect of compressibility for stability is disscused.     

Population coherent control of Rydberg potassium atom via adiabatic passage

The time-dependent multilevel approach(TDMA) and B-spline expansion technique are used to study the coherent population transfer between the quantum states of a potassium atom by a single frequency-chirped microwave pulse.The Rydberg potassium atom energy levels of n=6-15,l=0-5 states in zero field are calculated and the results are in good agreement with other theoretical values.The time evolutions of the population transfer of the six states from n=70 to n=75 in different microwave fields are obtained.The results show that the coherent control of the population transfer from the lower states to the higher ones can be accomplished by optimizing the microwave pulse parameters.