高斯－谢尔模型光束的变换特性

在一般情况下推导出高斯－谢尔模型光束经ＡＢＣＤ光学系统变换后的相干模迭加表示式。     

高斯—谢尔模型光束的变换特性

在一般情况下推导出高斯－谢尔模型光束经ＡＢＣＤ光学系统变换后的相干模迭加表示式。     

Transformation Properties of Dynamical Systems at the Quantum Level

Based on the generating functional of Green function for a dynamical system, the general equations of transformation properties at the quantum level are derived. In some cases they can be reduced to the quantum Noether theorem. In some other cases they can be reduced to momentum theorem or angular momentum theorem etc. at the quantum level. An example is presented and it shows that the classical conservation laws don’t always preserve in quantum theories. PACS: 11.10.E     

半凸旋转棱镜对光束变换

本文对半凸旋转棱镜对光束变换进行了详细的理论分析，定量计算了变换光束的空间强度分布。结果表明经半凸旋转棱镜变换产生的光束具有“无衍射”性质     

离轴椭圆厄米-高斯光束通过一阶光学系统的变换特性

从Collins公式推导出离轴椭圆厄米-高斯光束通过一阶光学系统的变换关系,并以透镜系统为特例研究了偏心厄米-高斯光束的传输特性,在垂直于x轴截面内强度分布仍是厄米-高斯函数形式并保持阶次不变,在传播方向上光束中心轨迹线是一条过焦点的直线.     

基于矩变换的生物组织光学特性参量反演

针对漫射模型在近光源区具有较大模型误差,导致光学特性参量反演准确度较低的问题,提出了一种利用矩变换,改变原始数据形态,提高反演准确度的方法.比较了不同阶次条件下的光学特性参量反演准确度和拟合残差的统计分布状况,分析了不同信噪比下重构系数的相对误差.对25组数据的研究结果表明:3阶矩变换可显著提高两个光学参量(μa、μ′s)的估计准确度.在无噪音条件下,吸收系数μa重构的平均相对误差为7.04%;有效散射系数μ′s重构的平均相对误差为5.55%,相比于自然对数变换,μa降低了8.57%;μ′s降低了32.73%.在信号噪音满足一定条件情况下(大于50dB),3阶矩变换仍然能获得较高的光学参量反演准确度.矩变换方法能有效地提高光学特性参量反演估计准确度.     

一种用于研究一类球形隐身外壳材料光学特性的坐标变换方法

针对研究一类球形隐身外壳材料光学特性的问题,设计一种基于空间压缩拉伸的坐标变换方式,利用几何光学光线追踪的方法,描绘光线传播的斗篷行为,用以研究隐身材料的光学特性,建立一个二维的变换模型来研究隐身材料:在大圆中存在一个小圆,两圆圆心重合,小圆将大圆内的空间分割成两个部分,等间距的直线穿过模型,分别与两个圆相交。通过坐标变换将圆内的空间进行拉伸,同时将圆外的空间压缩,从而使得光线在隐身材料外壳中发生扭曲实现隐身效果,利用Matlab进行编程模拟作出图像并与实验样条曲线进行对比,根据对比结果修改完善程序并将其拓展到三维情况下。结果表明,这样的坐标变换有利于解释在各向异性材料中某个球形区域内的隐身效应。     

Scattering Theory with Finite-Gap Backgrounds: Transformation Operators and Characteristic Properties of Scattering Data

We develop direct and inverse scattering theory for Jacobi operators (doubly infinite second order difference operators) with steplike coefficients which are asymptotically close to different finite-gap quasi-periodic coefficients on different sides. We give necessary and sufficient conditions for the scattering data in the case of perturbations with finite second (or higher) moment.     

Influence of Surface Transition Layers on Phase Transformation and Pyroelectric Properties of Ferroelectric Thin Film

Taking into account surface transition layers （STLs）, we study the phase transformation and pyroelectric properties of ferroelectric thin films by employing the transverse Ising model （TIM） in the framework of the mean field approximation. The distribution functions representing the intra-layer and inter-layer couplings between the two nearest neighbour pseudo-spins are introduced to characterize STLs. Compared with the results obtained by the traditional treatments for the thin films using only the single surface transition layer （SSL）, it is shown that the STL model reflects a more realistic and comprehensive situation of films. The effects of various parameters on the phase transformation properties have shown that STL can make the Curie temperature of the film higher or lower than that of the corresponding Sulk material, and the thickness of STL is a key factor influencing the film properties. For a film with definite thickness, there exists a critical STL thickness at which ferroelectricity will disappear when the intra-layer and inter-layer interactions are weak.     

高压下TiN的结构转变、弹性和热力学性质的第一性原理计算

 利用基于密度泛函的第一性原理,计算了高压下TiN的结构转变、弹性和热力学性质。计算结果表明：在压力作用下,TiN经历了从NaCl型结构到CsCl型结构的转变,转变压力为348 GPa;TiN的弹性系数随着压力的增加呈线性增加规律。此外,还给出了德拜温度和热容量这两个重要热力学量与温度和（或）压力的依赖关系。     

Study Hankel Transforms and Properties of Bessel Function via Entangled State Representation Transformation in Quantum Mechanics

In Phys. Lett. A 313 (2003) 343 we have found that the self-reciprocal Hankel transformation (HT) is embodied in quantum mechanics by a transform between two entangled state representations of continuum variables. In this work we study Hankel transforms and properties of Bessel function via entangled state representations' transformation in quantum mechanics.     

Transformation of the Microwave Resonance Properties of Metastructures with CdS and CdSe at One- and Two-Photon Excitation

JETP Letters - Photonically controlled metastructures containing resonant conducting dipole and chiral elements with CdS and CdSe in gaps have been proposed, implemented, and studied in a waveguide...     

Martensite Transformation,Magnetotransport Properties,and Magnetocaloric Effect in Ni47Mn42In11 Alloy

Physics of the Solid State - The structure, electric properties, and magnetocaloric effect in Ni47Mn42In11 ferromagnetic alloy in which the martensite transformation temperature is close to room...     

高压下BeP2N4结构相变和电子结构的第一性原理计算

 基于密度泛函理论的第一性原理方法,计算了硅铍石型和尖晶石型结构BeP₂N₄的总能量随体积的变化关系。利用Brich-Murnaghan状态方程,通过能量和体积拟合,得到了2种结构的体变模量及其对压强的一阶导数。在压力作用下,BeP₂N₄的相变是从硅铍石型结构（空间群R-3,No.148）转变到尖晶石型结构（空间群Fd-3m,No.227）,计算出的相变点与其它理论值符合得非常好。同时计算了BeP₂N₄的相对晶格常数a/a₀和相对体积V/V₀的压缩率,在低压下发现,尖晶石结构BeP₂N₄的压缩率接近金刚石,进一步计算了不同压力下的体弹模量B_H、剪切模量G_H、B_H/G_H和杨氏模量E。此外,对两种结构的BeP₂N₄的电子态密度和带隙随压强的变化关系进行了计算和分析。结果表明：在压力作用下,上价带顶向费米能级移动,并有一定的展宽。Be—N、P—N键缩短,电子转移增加,导致电荷发生重新分布。     

Transformation Plasma Physics

Plasma technology has widespread applications in many fields, whereas the methods for manipulating plasma transport are limited to magnetic control. In this study, we used a simplified diffusion-migration approach to describe plasma transport. The feasibility of the transformation theory for plasma transport was demonstrated.As potential applications, we designed three model devices capable of cloaking, concentrating, and rotating plasmas without disturbing the density profile of plasmas in the ...     

Phase Transformation and Enhancing Electron Field Emission Properties in Microcrystalline Diamond Films Induced by Cu Ion Implantation and Rapid Annealing

Cu ion implantation and subsequent rapid annealing at 500℃in N_2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm~2 V~(-1)S~(-1)for microcrystalline diamond(MCD)films.Its electrical field emission behavior can be turned on at E_0=2.6 V/μm,attaining a current density of 19.5μA/cm~2 at an applied field of 3.5 V/μm.Field emission scanning electron microscopy combined with Raman and x-ray photoelectron microscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films,forming conduction channels for electron transportation.     

离散Hankel变换

首次提出了离散Hankel变换,从理论上给出了离散Parseval定理和变换矩阵。引入了抽样权重因子。并讨论了抽样原则及S因子对计算精度的影响。     

Convolution Theorem of Fractional Fourier Transformation Derived by Representation Transformation in Quantum Mechancis

Based on our previous paper （Commun. Theor. Phys. 39 （2003） 417） we derive the convolution theorem of fractional Fourier transformation in the context of quantum mechanics, which seems a convenient and neat way. Generalization of this method to the complex fractional Fourier transformation case is also possible.     

Convolution Theorem of Fractional Fourier Transformation Derived by Representation Transformation in Quantum Mechancis

Based on our previous paper (Commun. Theor. Phys. 39 (2003) 417) we derive the convolution theorem of fractional Fourier transformation in the context of quantum mechanics, which seems a convenient and neat way. Generalization of this method to the complex fractional Fourier transformation case is also possible.