复合静电—磁浸没透镜的宽束曲轴聚焦性质及像差理论

研究了新型的复合静电－磁浸没透镜的曲光轴高斯电子光学性质及像差特性。应用宽束曲轴理论，导出了三维局部正交坐标系中的电子运动的中心轨迹方程和曲光轴的近轴轨迹方程；利用数学软件Mathematica推导出了复合静电－磁浸没透镜全部曲轴二级像差系数。作为实例，中针对轴上磁场和电场具有某种解析表达式的旋转对称的静电－磁浸没透镜系数，计算了它的曲轴高斯聚焦特性和二级像差，并给出了二级像差分布图形。     

复合静电-磁浸没透镜的宽束曲轴聚焦性质及像差理论

研究了新型的复合静电 磁浸没透镜的曲光轴高斯电子光学性质及像差特性。应用宽束曲轴理论 ,导出了三维局部正交坐标系中的电子运动的中心轨迹方程和曲光轴的近轴轨迹方程 ;利用数学软件Mathematica推导出了复合静电 磁浸没透镜全部曲轴二级像差系数。作为实例 ,文中针对轴上磁场和电场具有某种解析表达式的旋转对称的静电 磁浸没透镜系数 ,计算了它的曲轴高斯聚焦特性和二级像差 ,并给出了二级像差分布图形     

层状横观各向同性地基性质对刚性条基摇摆振动的影响

分析了土体的横观各向同性及层状性质对刚性条形基础摇摆振动的影响。首先利用解析层元法得出层状横观各向同性地基的总刚度矩阵。再根据刚性条形基础与地基相互作用的混合边值条件,建立了一组对偶积分方程,并借助Jacobi正交多项式求解了该对偶积分方程,从而得到地基动力柔度系数。计算结果与已有文献的结果吻合较好。同时,算例结果表明:土的水平向与竖向弹性模量比的减小、竖向的剪切模量与弹性模量比的增大,以及水平向泊松比与竖向泊松比比值的增大,都将导致地基动力柔度系数增大;而且,层状地基中上层土的弹性模量的减小使得地基动力柔度系数也增大。     

利用Matlab开发平台的炉膛火焰图像温度检测方法

介绍了目前炉膛火焰检测系统的技术特性及用于火焰检测的数字图像处理技术。通过对炉膛火焰温度的CCD数字图像检测方法可行性的分析，设计了用于监测炉膛温度面分布的试验系统；通过火焰图像象素RGB值与温度的对应关系，建立了火焰图像的温度场曲线，通过原理性试验初步验证了该技术的可行性。     

利用瑞利波检测层状混凝土结构的材料特性

为获得层状混凝土结构的材料特性,利用瑞利波在半无限大混凝土和层状混凝土中的传播规律,分别建立两种模型中瑞利波传播的波速方程。基于获得的层状混凝土结构中瑞利波的波速方程,提出一种从实测波速来推定混凝土材料特性的反演方法。通过数值计算获得两种模型中波速和混凝土弹性模量的关系曲线,理论计算结果与实验结果基本一致。研究结果表明:由于混凝土层的相互作用,结构中存在多个瑞利波振动模态以及相应的波速,同时波速和上层混凝土弹性模量之间存在对应关系。建立的研究方法和计算结果可直接应用于实际混凝土的瑞利波检测。     

平衡盘喷焊层径向层状剥落的原因及防止方法

分析了注水泵平衡盘一步法多道喷焊形成径向层状剥落的原因。通过改变涂层设计，增大火焰功率，改进喷枪的行进路径，使用单道喷焊层，保证喷焊层熔透，可以防止径向层状剥落的产生，提高生产效益。     

平衡盘喷焊层径向层状落的原因及防止方法

分析了注水泵平衡盘一步法多道喷焊形成径向层状剥落的原因，通过改变涂层设计，增大火焰功率，改进喷枪的行进路径，使用单道喷焊层，保证喷焊层熔透，可以防止径向层状剥落的产生，提高生产效益。     

微穿孔板-聚合物层状结构材料的制备和吸声性能

以微穿孔板(MPP)、聚氨酯泡沫(PU)、丁腈橡胶(NBR)和空腔(AG)为原料,根据不同的结构顺序分别制备出MPP-AG共振结构、MPP-PUFM层状结构、MPP-AG-NBR-PUFM多层结构材料和NBR-PUFM-MPP-AG多层结构材料,研究了MMP穿孔率、PUFM厚度、泡沫层孔径、泡沫厚度和结构交替顺序对复合材料吸声性能的影响。结果表明：在频率较低的条件下MPP穿孔率越低或在较高频率条件下MPP穿孔率越高,层状结构材料的吸声系数越高;随着PUFM厚度的增大层状结构材料的共振峰值频率向低频方向移动。与MPP-PUFM层状结构材料相比,MPP-AG-NBR-PUFM在500~1600Hz频率范围的平均吸声系数由0.58提高到0.66;NBR-PUFM-MPP-AG多层结构材料具有优异的中低频吸声性能,频率为400 Hz时最大吸声系数达到0.94,频率为2700 Hz时吸声系数达到0.85。     

高聚物／无机物插层型纳米复合材料

高聚物／无机物插层型纳米复合材料由高聚物插入层状无机物复合而成，这类材料可分为层间插入型和层状分散型。介绍了其制务方法，着重评述 其结构与性能以及应用的最新研究进展。     

星型线分布椭圆入口七孔流量传感器的研究

基于流体连续性方程、伯努利方程、星型线方程,差压式流量计的基本测量原理,边界层理论,计算机模拟系统以及水流量试验装置,将星型线理论应用于差压式流量计节流元件中,建立了星型分布椭圆入口七孔流量传感器的数学模型,并确定了基本结构形式,采用仿真模拟与实流标定相结合的方法,采集流量系数,通过数值分析不同参数的结构形式的流量系数,最终确定星型分布椭圆入口七孔流量传感器的结构形式及精确度等级。     

Aberrated lenses for generating flattened laser irradiance

Expressions for describing Gaussian beams focused by a lens with spherical aberration have been derived. Numerical results show that, when the coefficient of the spherical aberration is negative, one can obtain flattened laser irradiance at two positions along the focused field. The larger the coefficient of negative spherical aberration, the larger the flatness is. The effect of the Fresnel number of the focusing lens on the flattened laser irradiance is also investigated.     

The Fabry-Perot Interferometer. History,Theory, Practice and Applications

Abstract

A simple algebraic algorithm is proposed as a computational tool for the thin-lens design of a triplet which consists of a singlet and a cemented doublet. The triplet is required to yield specified amounts of lens power, primary spherical aberration, central coma, longitudinal chromatic aberration and secondary spectrum. The three element powers of the triplet are first obtained by solving the simultaneous linear equations of the total lens power, longitudinal chromatic aberration and secondary spectrum. A quadratic equation is obtained by combining the equations of spherical aberration and central coma, and the lens shapes are then obtained by solving this quadratic equation. The solving process is purely algebraic and is therefore easy to calculate and guarantees that all the solutions can be found.     

Spectral switches of vector Gaussian Schell-model beams passing through a spherically aberrated lens

On the basis of the polarization matrix and propagation equation of the cross-spectral density matrix, the spectral changes for the on-axis spectrum of vector Gaussian Schell-model (GSM) beams focused by a spherically aberrated lens are studied, where the influence of the spherical aberration, correlation and polarizer on the behaviour of the spectral switch is stressed. It is shown that the spectrum of vector GSM beams passing through a spherically aberrated lens may be blueshifted and redshifted in comparison with the source spectrum, and a spectral switch may also take place. However, there are only blue shifts for two kinds of cases passing through an aberration-free lens and an astigmatic lens. The spectral switch arises from the oscillation of the spectral modifier with frequency.     

Studies on the diffraction image of a thermal lens

We calculated the intensity distribution behind a thermal lens by using a numerical quadrature of the Fresnel diffraction integral and compared it to several given approximate models for laser light detection in the center behind a thermal lens, which includes a new approximate solution of the diffraction integral with applicability to strong thermal lenses. Consideration of the aberrant nature of the thermal lens is crucial even if the thermal lens is weak. A simple approximate formula for the position of the most intense interference ring stating a linear dependence of the thermal lens strength is given. The transverse profile of a weak thermal lens is discussed. It is shown that spherical aberration modifies the central intensity even if a Gaussian profile is observed.     

Structural design of multicomponent lens systems

The thin lens design of multicomponent systems with a prespecified set of primary aberration residuals and Gaussian characteristics usually starts with the choice of a lens type followed by a selection of the glasses to be used for the elements of its different components. An alternative scheme is reported in this paper which aims at utilizing these degrees of freedom in a more effective way. The detailed structure of the individual components and the glasses to be used in the lens elements comprising them are determined after the feasibility of attaining the given aberration targets with viable components has been ascertained on a preliminary layout of components obtained from a consideration of Gaussian requirements and Petzval curvature of the desired system.     

Using the method of conservative scalars for the calculation of thermal radiation of turbulent diffusion flame

Data on laser probing of laboratory flames are used to quantitatively estimate the contribution made by turbulent fluctuations of thermodynamic parameters to thermal radiation of hydrogen diffusion flame. The coefficients in the equation of radiation transfer are averaged directly by samplings of instantaneous values of temperature and concentration; this helps eliminate errors associated with the use of model distribution functions. The obtained results are used to verify the approximate method for the calculation of thermal radiation of flame, which is based on the assumptions of thermochemical equilibrium of combustion and normal distribution of the coefficient of mixture.     

介电润湿液体透镜仿生复眼的设计与仿真

为解决仿生复眼系统不能自适应变焦的问题,提出了一种基于介电润湿液体透镜曲面阵列的可变焦仿生复眼系统。分析系统结构对成像性能的影响,计算系统的自适应变焦能力及相应像平面可移动范围。结果表明:系统成像的视场角随着基底曲率的增大而增大。相比于非均匀透镜阵列,均匀透镜阵列可明显降低系统的离焦像差。适当减小子透镜单元尺寸,也可以达到降低边缘透镜离焦像差的目的。当物距或者接收器位置发生改变时,通过调整子透镜单元焦距降低系统的离焦像差。系统接收器可移动范围为1.9 mm~15 mm。     

Differential equation for normal glass dispersion and evaluation of the secondary spectrum

Some of the questions concerning secondary chromatic aberration at both sides of the visible band of the spectrum are the following: (1) What is the bandwidth at different wavelengths, given the permissible chromatic aberration circle and the lens aperture? (2) What is the size of the chromatic aberration circle, given the wavelength, the bandwidth, and the lens aperture? The answers to these and other questions may be found with the new definitions of V-number and relative partial dispersion P based on infinitesimal bandwidths that we propose. In addition, an alignment chart for the secondary color of a normal glass doublet is presented, so fast answers to the questions posed above and to other questions concerned with secondary color can be found. In addition, a continual challenge in computer-aided lens design is the use of optical glasses as design parameters in simultaneous optimization of lens systems over various regions of the spectrum. This problem could be solved if we could find an ideal glass family, not too different from real glasses, such that, given the refractive index n and the V-number at any wavelength, the indices at all wavelengths could be determined. Therefore we derive a differential equation for normal glass dispersion and present a recursive solution.     

Modeling edge flame propagation in a stratified fuel gas-air mixture

Edge flame (EF) propagation in propane-air mixture stratified in the gravitational field has been physically modeled. Experiments in a rectangular channel open at one end have been used to study the formation of zones of flame propagation. It is established that the EF only propagates within a narrow region of the channel, the width of which depends on the initial mixture composition and the time for which its stratification takes place. The gas mixture composition in this zone varies from the lower to upper limit of the ignition concentration. It is found that the local maximum temperature of the EF varies along its surface and the flame oscillates at the Brunt-V?is?l? frequency.