图解法分析自聚焦透镜的物像关系

从自聚焦透镜的成像特性出发,导出了自聚焦透镜与普通透镜相同的高斯物像公式.采用理想光具组图解法分析了自聚焦透镜子午光线的成像.该成像法只需要找出基点、基面的位置,利用两条特殊光线,便可以在确定物体具体位置和高度的情况下通过图解法,得出像的具体位置和大小.对直径为1.82 mm的自聚焦透镜的物像关系进行了实验研究,结果表明图解法能够很好地分析自聚焦透镜成像.     

三反射式柱面光学系统设计及优化

针对传统单片柱透镜和柱面反射镜成像光束不理想以及视场通常小于1°,提出并设计了一种三反射式柱面结构.对柱面光线追迹及单片柱面镜成像进行了深入分析,分别设计了三反射式圆柱面和二次曲线柱面系统,提出了一种基于抛物柱面镜理想线聚焦的新型像差优化方法,使其在子午面方向各视场调制传递函数得到最佳优化,并达到成像光谱仪等在狭缝方向卜高空间分辨率要求.其子午面总视场均达到了3°,在45 lp/mm分辨率条件下,边缘视场子午面方向的调制传递函数分别优于0.2和0.6.     

用于ICF内爆诊断的质子成像磁透镜理论设计

根据加速器束流输运线设计的比例定律,设计了适用于ICF内爆DD反应产生的3.6 MeV准单能质子束成像的磁透镜系统。通过公式推导以及束流动力学追踪模拟,获得了类似于几何光学成像中的物像关系,并使用三维粒子追踪模拟验证了磁透镜成像的物像关系。物像关系的满足,使得可以对磁透镜系统进行封装,然后根据物像关系, 选择不同的物距以及相应的相距, 就可以对物体成不同大小的像。     

诺莫图法在薄透镜和球面镜成像分析中的应用

在满足近轴光线的条件下,可以利用成像公式和光路图法分析薄透镜或球面镜的物像关系,而本文介绍的这种诺莫图法,可以在直角坐标系上用坐标图示法分析薄透镜和球面镜的物像关系,不仅可以精确求得实物或虚物的成像位置,还可以判断出像的性质,具有简单、直观等特点,可以作为分析物像关系的一种补充手段.     

平面棱镜系统成像方向的追迹模拟

为了清晰说明平面棱镜系统成像方向的判定方法,推导了光在非共轴光学系统的追迹公式,对平面棱镜系统的物像坐标变化过程进行了模拟.通过棱镜对物像坐标变化过程的模拟,进一步说明了教科书中棱镜成像方向判定方法,结果显示,模拟棱镜成像是理解棱镜成像方向判定方法最为直观可行的手段,不仅有利于学生理解这种判定方法,还可以促进学生对这种判定方法的记忆.模拟过程还可以使学生深刻理解在课堂中不易理解的棱镜中各种术语定义.     

水下气泡高速摄影光学系统设计

为了研究水下气泡的粒径、速度和浓度特性,提出基于高速电荷耦合器件(CCD)的气泡照明和三维摄影光学系统.采用532nm半导体激光器,基于伽利略结构用三个柱面镜设计了厚度1.5mm,宽度44mm的片光源。设计物像距530mm,放大率为0.4,1,2.5倍(×)的摄影光学系统,每组均由共用前组镜和会聚镜组成,中间以平行光中继。通过同步移动片光源和共用前组镜实现60mm×40mm视场内二维高速成像和纵向5mm扫描,具有结构简单、性能可靠的特点。对设计结果进行评价,0.4,1,2.5×成像光学系统在0.707ω,50lp/mm时调制传递函数值分别为0.58,0.55和0.38,能够分辨粒径范围为10～450μm的气泡。     

负折射率材料单球面近轴成像奇特规律的研究

研究了负折射率(n′<0)材料单球面折射对近轴光线的成像规律.理论推导证实负折射率材料单球面近轴成像的所有公式与我们所熟悉的常规材料(n′>0)单球面的完全相同,但由于n′<0,它的成像规律完全不同于常规材料的.文中通过物距-像距曲线比较了两种材料的物-像关系,并对(n′<0,f′>0,f>0)情形下的物像位置、虚实正倒、缩放规律等进行阐述,给出了物像空间的对应图示.     

宽谱段改进型Wadsworth光栅型成像光谱仪光学设计

针对传统的Wadsworth光学系统无法应用于宽谱段高分辨率成像光谱仪的情况,给出了一种改进的光学系统方案。通过在Wadsworth系统中加入柱面镜的方法,改变了子午和弧矢方向成像聚焦距离。在对像散和光程分析的基础上,计算获得了改进型Wadsworth成像光谱仪光学系统的最优成像条件,即柱面镜的最优放置位置、最优倾斜角和最优楔角。以一个工作波段为400~800nm的改进型光学系统设计实例,对设计理论进行了验证。设计结果表明系统具备良好的光学成像质量,探测器在奈奎斯特频率(20lp/mm)下全视场全波段调制传递函数值达到0.57以上,光谱分辨率达到1.6nm,实现了对Wadsworth系统的有效改进。     

双凸厚透镜曲率半径和折射率的测定

运用球面成像原理,应用物像同屏和物像异屏方法,采用透镜折反折和折折成像,测定双凸厚透镜的曲率半径和折射率,并利用焦距公式计算得双凸厚透镜的焦距.该实验测定方法,体现了透镜成像的过程,得到了双凸厚透镜曲率半径和折射率的计算公式,拓展了透镜光学参量测定的方法和途径.     

物像关系检测仪

物像关系检测仪闵春宗，左云彤（四平师范学院１３６０００）在光学实验中，为了验证对光学成像的四个基本元件（凸透镜、凹透镜、四面镜和凸面镜）的焦距和物像关系的测量结果是否正确，我们制做了物像关系检测仪．这套装置亦可用于课堂教学．１．检测仪的构造如图１所示...     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

A study on the best irradiation dose of X-ray for Hep-2 cells by Fourier transform infrared spectroscopy

Fourier transform infrared spectroscopy (FTIR) was employed to study the human epidermis larynx carcinoma cell lines (Hep-2) which were irradiated by different doses of X-ray.The results show that (1) the irradiation of X-ray damages the structure of the CH3 groups of the thymine in DNA,which restrains the reproduction of Hep-2 cells effectively,(2) the 8 Gy dose of X-ray irradiation changes the framework and the relative contents of some proteins,lipids and the nucleic acid molecules intercellular in the greatest degree,and (3) the 8 Gy dose of X-ray irradiation is the best irradiation dose for lowering the degree of the cancerization of Hep-2 cells according to the criteria for the degree of the cancerization reported recently.Meanwhile,the apoptosis of these cells were detected by using flow cytometry (FCM) primarily.It shows that the apoptotic ratio of the Hep-2 cells depends on the irradiation dose to some extent,but is not linearly.And the apoptotic ratio of the 12 Gy dose group is the maximum (20.36%),but the apoptotic ratios of the 2 to 8 Gy dose groups change little.     

Analysis of Laser-generated Rayleigh wave on viscoelastic materials

In order to understand the viscoelasticity of material, this research has been conducted to study the propagation characteristics of viscoelastic Rayleigh wave theoretically. A model is presented for the pulsed laser generation of ultrasound on viscoelastic medium surface. Referred to the Kelvin model, the frequency equation and the normal displacement of viscoelastic Rayleigh wave were derived, the influence of the viscoelastic modulus on dispersion and attenuation was discussed. From the theoretical calculation, it is shown that the effect of viscoelasticity on the attenuation of Rayleigh wave is more than that on its dispersion. In the case of a weak viscosity, the attenuation of viscoelastic Rayleigh wave is directly proportional to viscosity modulus; the effect of shear viscosity on the attenuation is much more than that of bulk viscosity. The transient response of viscoelastic Rayleigh wave was also simulated using Laplace and Hankel inversion transform, which are showed in good agreement with the theoretic predictions. The model provides a useful tool for the determination of viscoelastic parameters of medium.     

Synergistic effects on iodine release in potassium iodide solution by combination of ultrasound and visible light irradiations

Iodine release in potassium iodide solution has been investigated under the irradiations of ultrasound and visible light respectively and simultaneously. We have observed that the amount of iodine liberated under the combined irradiation of ultrasound and visible light is larger than the sum of that under the respective irradiations of ultrasound and visible light, indicating a synergistic effect of ultrasound and visible light irradiations. Based on the investigation of the reaction kinetics of iodine liberated, we have ascribed the synergistic effect to the perfect stirring of the photochemical reactor induced by the applying simultaneous ultrasound. The ideal stirring can result in the homogenization of the primary light effect in the whole reaction medium, which induces the acceleration of the photochemical reaction. On behavior of our knowledge, there are few reports on the investigations of utilizing the combination of ultrasonic energy and light energy to accelerate the reaction yield and rate as well as the kinetics of the reaction.     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Testifying experiment of the multi-pulse phenomena of capillary discharge soft-X-ray laser

In a capillary discharge experiment for the neon-like argon lasing, we have proposed an experimental scheme to verify that the multi-spike of X-ray diode (XRD) signal is a multi-pulse laser or is a reflection of the laser pulse in the XRD.The ceramic capillary has an inner diameter of 3mm and a length of 200mm.At the gas pressure of 28Pa and discharge current of 27kA, stable lasing has been realized.The experimental results prove that the multi-spike of XRD signal is a reflection of the electromagnetic signal produced by the laser pulse in the XRD.The improved electrocircuit scheme of the XRD to minimize the reflection phenomena is also found.     

Harmonic operation of high gain harmonic generation free electron laser

In high gain harmonic generation (HGHG) free electron laser (FEL), with the right choice of parameters of the modulator undulator, the dispersive section and the seed laser, one may make the spatial bunching of the electron beam density distribution correspond to one of the harmonic frequencies of the radiator radiation, instead of the fundamental frequency of the radiator radiation in conventional HGHG, thus the radiator undulator is in harmonic operation (HO) mode. In this paper, we investigate HO of HGHG FEL.Theoretical analyses with universal method are derived and numerical simulations in ultraviolet and deep ultraviolet spectral regions are given. It shows that the power of the 3rd harmonic radiation in the HO of HGHG may be as high as 18.5% of the fundamental power level. Thus HO of HGHG FEL may obtain short wavelength by using lower beam energy.     

Radiative spectra of thermal electromagnetic noise induced by planar realistic dielectrics

Spectral characteristics of stochastic fields and their spatial derivatives in various planar structures composed by lossy materials described by realistic dielectric functions are numerically calculated based on solutions to the problems of multipolar electromagnetic fields in a plane layered geometry. A displacement of the maximum of the spectral power densities for spatial derivatives of fluctuating fields to the high-frequency domain, a resonant increase in the density of states of the fluctuating fields at the frequencies of interface excitations and interference modes for the radiative part of the spectra, the influence of geometry on the density of states, and other peculiarities are found by numerical calculations and graphically demonstrated. Interpretations of the above effects are provided.     

Factors affecting the spectrum of an electromagnetic light wave on scattering from a semisoft boundary medium

The spectrum of an electromagnetic light wave on scattering from a semisoft boundary medium is discussed within the accuracy of the first-order Born approximation. It is shown that spectral shifts and spectral switches are affected both by the polarization of the incident light wave and by the characters of the scat-tering medium. Moreover, numerical results show that the direction at which the spectral switch occurs is governed by the characters of the scattering medium, whereas the magnitude of the spectral switch is affected by the polarization of the incident light wave.     

Formation and dynamics of Saturn and its disk simulated by using a new N-body model

The formation of Saturn and its disk is simulated using a new N-body self-gravitational model. It is demonstrated that the formation of the disk and the planet is the result of gravitational contraction of a slowly rotated particle cloud that have a shape of slightly deformed sphere. The sphere was flattened by a coefficient of 0.8 along the axis of rotation. During the gravitational contraction, the major part of the cloud transformed into a planet and a minor part transformed into a disk. The thin structured disk is a result of the electromagnetic interaction in which the magnetic forces acting on charged particles of the cloud originate in the core of the planet. The simulation program gives such parameters of Saturn as the escape velocity of about 35 km/s at the surface, density, rotational velocities of the rings and temperature distribution.