实验室黑白肖像艺术照的拍摄及制作方法的改进

本文对实验室条件下拍摄黑白艺术肖像的方法作了探讨,对放大相片的方法作了改进,给出了实验数据,并对拍摄结果作了分析和讨论。实验获得了放大尺寸的人物肖像艺术照片。     

明室全息照相技术

本实验采用SRP—I型红敏光致聚合物干版,在明室条件下对反射式全息图的拍摄过程及条件进行了研究。     

可获得高衬比干涉条纹的实时全息记录方法

本文提出了一种可以获得高衬比的实时全息记录方法,它通过分析所记录的第一张实时全息图来获得拍摄最佳衬比实时全息图的拍摄参数,文中指出了拍摄最佳衬比实时全息图需要满足的条件,给出了理论分析和实验验证,实验结果与理论相符甚好,对于透明物体的实时法全息图.条纹衬比可接近最佳值1.     

非线性条件对记录多重全息图的影响

通过计算和比较在线性条件及非线性条件下各级多重衍射像的光强及相位分布情况,分析了非线性条件对多重全息图成像效果的影响.提出了拍摄多重全息图的合适条件,并用实验加以验证.     

白光再现全息照相

简述了激光全息照相的原理,设计出全息照相的拍摄光路,探索出能成功拍出全息图的方法以及能实现白光再现的实验参数。总结出拍摄反射全息的条件,并能了解全息照相与普通照相的区别,以及全息照相的应用及开拓。     

全息照相实像的优化拍摄与再现

从全息照相的基本理论出发,分析了全息照相实像的产生条件,提出了用正入射平行光拍摄和再现全息照相实像的方案.实验表明,用正入射平行光拍摄和再现全息实像能得到满意的效果.在不同的散射介质中进行了全息实像的再现实验,确定了一种符合要求的再现介质.     

立体显示系统的消畸变研究

许多场合需要精确观看与真实景物相似的立体影像,立体拍摄和再现系统应无畸变。提出的再现立体影像垂轴放大率概念,其具有与拍摄相机的垂轴放大率互补的特性。由此根据再现立体像的垂轴放大率与轴向放大率应相等这一消畸变的基本要求推导了立体拍摄和再现系统的消畸变条件。提出了消畸变系统的设计方法和设计流程,计算并通过验算证明了设计方法的正确性。该方法设计流程简单合理,设计的立体拍摄和再现系统,在正面观看时可在很大的纵深范围内得到消畸变立体影像。     

用双脉冲全息摄影研究手电钻的动态特性

本文在叙述双脉冲双曝光的原理基础上,提出了拍摄可供定量分析用的全息图所要求的条件及其所采取的技术措施;并且推算出脉冲激光器本身的输出能量与其所能拍摄最大面积的关系式。用输出能量为180mJ,曝光时间为25ns,脉冲间隔可调的双脉冲激光器,拍摄了直径为600mm手电钻工作面的六张双曝光全息图,研究手电钻的空载和切削时的动、静态特性,计算出条纹相对的位移量。     

分数傅里叶变换全息图及其在防伪中的应用

提出分数傅里叶变换全息图,讨论了它的性质。拍摄分数傅里叶变换彩虹全息图。基于其再现条件的特殊性,可建立一种新型的伪全息术。     

迈克耳孙干涉仪的新用途

本文提出了将迈克耳孙干涉仪加以适当改装后，在不用全息防震台的条件下，拍摄多种全息图的原理和方法．     

Mathematical simulation of interactions of protein molecules and prediction of their reactivity

A physical model of interactions of protein molecules has been developed. The regularities of their reactivity have been studied using electrostatics methods for two histone dimers H2A–H2B and H3–H4 assembled from monomers. The formation of histone dimers from different monomers has been simulated and their ability to the formation of stable compounds has been investigated by analyzing the potential energy matrix using the condition number. The results of a simulation of the electrostatic interaction in the formation of dimers from complete amino acid sequences of selected proteins and their truncated analogs have been considered. The calculations have been performed taking into account the screening of the electrostatic charge of charged amino acids for different concentrations of the monovalent salt using the Gouy–Chapman theory.     

Study of Tachyon Warm Intermediate and Logamediate Inflationary Universe from Loop Quantum Cosmological Perspective

We have studied the tachyon intermediate and logamediate warm inflation in loop quantum cosmological background by taking the dissipative co-efficient Γ=Γ₀ (where Γ₀ is a constant) in “intermediate” inflation and Γ=V(φ), (where V(φ) is the potential of tachyonic field) in “logamediate” inflation. We have assumed slow-roll condition to construct scalar field φ, potential V, N-folds, etc. Various slow-roll parameters have also been obtained. We have analyzed the stability of this model through graphical representations.     

Dynamics of charge carriers at the place of the formation of a muonic atom in diamond and silicon

The space-time distribution of charge carriers at the place of the location of a muonic atom formed when a negative muon is captured by an atom of the lattice has been numerically simulated taking into account the self-consistent electric field. The results of ??SR experiments with negative muons in diamond crystals have been explained and reasons for the difference in the behavior of the spin polarization of the negative muon in boron-doped diamond and in silicon have been revealed. The condition of the validity of the analytical solution of this problem has been obtained. It has been shown that the muonic atom in diamond, in contrast to silicon, does not form a neutral acceptor center in the paramagnetic state during the muon experiment and remains in the diamagnetic state of a positive ion.     

光耦合理论及其在通信元器件中的应用

运用矩阵光学中变换矩阵的理论,并以重叠面积积分的方法为基础,推导出了普遍适用于计算光在光通信元器件中光耦合效率的理论公式,可通过设置边界条件计算单模光纤、扩束光纤、半导体激光二极管以及光波导等不同光学元器件之间的耦合效率。导出了计算单模光纤之间和单模光纤与扩束光纤之间存在横向偏移、轴向偏移时的耦合效率理论通用公式。阐述了扩束光纤的制作方法及光在扩束光纤中的传播,并根据所推导耦合效率理论公式计算结果与单模光纤间和单模光纤与扩束光纤间的耦合实验数据进行了比较。     

Free vibration of non-uniform nanobeams using Rayleigh–Ritz method

In this article, boundary characteristic orthogonal polynomials have been implemented in the Rayleigh–Ritz method to investigate free vibration of non-uniform Euler–Bernoulli nanobeams based on nonlocal elasticity theory. Non-uniform cross section of nanobeams has been considered by taking linear as well as quadratic variations of Young's modulus and density along the space coordinate. Detailed analysis has been reported for all the possible cases of such variations. The objective of the present study is to analyze the effects of nonlocal parameter, boundary condition, length-to-diameter ratio and non-uniform parameter on the frequency parameters. It is found that clamped nanobeams are having highest frequency parameters than other types of boundary conditions for a particular set of parameters. It is also observed that frequency parameters decrease with increase in scaling effect parameter. First four deflection shapes of non-uniform nanobeams have also been incorporated. In this analysis, some of the new results in terms of boundary conditions have also been included.     

考虑车辆相对运动速度的交通流演化过程的数值模拟

提出考虑了车辆相对运动速度的最佳速度跟车模型,对该模型稳定性进行了分析.对其所描述的交通流的演化过程进行了数值模拟,并与未考虑相对运动速度的最佳速度跟车模型作了比较. 关键词： 交通流 最佳速度 跟车模型 相对运动速度     

Flow effects in long-range dipolar field MRI

Incoherent spin motion, such as diffusion, can lead to significant signal loss in multiple spin echoes (MSE) experiments, sometimes to its complete extinction. Coherent spin motion, such as laminar flow, can also modify the magnetization in MSE imaging and yield additional contrast. Our experimental results indicate that MSE is flow-sensitive. Our theoretical analysis and experimental results show how the effect of the distant dipolar field can be annihilated by flow. This effect can be quantified by directly solving the nonlinear Bloch equation, taking into account the deformation of the dipolar field by motion. Unexpected results have been observed, such as a recovery of the dipolar interaction due to flow in the "magic angle" condition.     

色散条件下各向同性光纤中拉曼增益对光脉冲自陡峭的影响

基于光脉冲所满足的慢变函数,详细推导了包含拉曼增益的高阶非线性薛定谔方程,在考虑色散的条件下,运用分步傅里叶方法对其数值分析,进而模拟仿真了拉曼增益对高斯脉冲在各向同性光纤中传播时自陡峭效应的影响,并与不考虑拉曼增益的自陡峭效应作比较,从而得出拉曼增益在不同条件下对高斯脉冲自陡峭效应的具体影响方式.结果表明,拉曼增益会影响高斯脉冲的展宽、脉冲峰值衰减以及在前后沿的振荡,其影响程度与具体的自陡峭参数、脉冲功率和色散系数的大小有关.     

Ferromagnetic resonance relations in {111}-oriented garnet films

Microwave resonance relations for a {111} garnet film have been derived including the uniaxial as well as the first and second order cubic anisotropy contributions. Special attention has been given to the in-plane resonance condition. For this case the calculation has been made up to second order inK ₁/MH andK ₂/MH taking into account the influence of a nonideal in-plane configuration of the film.The author wishes to express his thanks to Dr. Z. Frait for valuable discussions.     

Nonlinear phenomena in chromatophores of photosynthetic bacteria excited by picosecond laser pulses

The contradictions between the fluorescence and difference absorption data on primary processes of photosynthesis have been elucidated taking into account light absorption by the excited states as well as nonlinear processes taking place in the chromatophore samples excited selectively by picosecond light pulses.