微通道板表面发雾的AES分析

应用俄歇电子能谱对微通道板表面发雾区域进行分析。分析结果表明,发雾区碳含量比正常区高三倍。由此可推测出,发雾是由碳污染引起的,而这种碳污染很可能是残留于微通道板上的某些有机物在烧氢时碳化所致。     

Position of starting spot in TLC: Influence on average plate height

Summary The influence of the distance between the solvent entry and the starting zone positions, Z₀, on the average plate height was studied. This factor was found to be of major importance and could be optimized. The Guiochon and Siouffi model greatly underestimates the plate height for low values of Z₀.     

一种位相板衍射图样的图像处理新方法

本文介绍了在半导体激光光纤和位相板相结合的准直情况下，利用ＣＣＤ探测器测量大尺寸形位误差的原理，并针对位相板衍射图像的特点，提出了一种处理此类衍射图样的图像处理新方法——投影法。同在时间上采用的多次平均的方法相比较，投影法相当于采用了空间上的平均，消除了ＣＣＤ表面保护玻璃形成的干涉条纹的影响，对空气扰动也起到了很好的抑制作用。并且使二维图像处理变为一维计算，大大提高了计算速度     

Fabrication of copper oxide nanofluid using submerged arc nanoparticle synthesis system (SANSS)

The optimal parameters are found for preparing nanofluid in our submerged arc nanoparticle synthesis system (SANSS) using a copper electrode. A suspended copper oxide nanofluid is thus produced at the current of 8.5–10 A, voltage of 220 V, pulse duration of 12 μs, and dielectric liquid temperature of 2°C. The CuO nanoparticle are characterized by transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), electron diffraction pattern (SAD) and electron spectroscopy for chemical analysis (ESCA). The equality volume spherical diameter of the obtained copper oxide particle is 49.1 nm, regular shape and narrow size distribution.This revised version was published online in August 2005 with a corrected issue number.     

Origination of In‐Phase Oscillations of Thin Plates with Aeroelastic Interaction

Synchronization of oscillations of thin elastic plates that are walls of a gasfilled channel is considered. The gas motion is described by a system of Navier–Stokes equations, which is solved using the secondorder MacCormack method with time splitting. The motion of the channel walls is described by a system of geometrically nonlinear dynamic equations of the theory of this plates, which is solved by the finitedifference method. Kinematic and dynamic contact conditions are imposed at the interface between the media. A numerical experiment is performed to determine typical dynamic regimes and study the transition of the aeroelastic system to inphase oscillations.     

Feigenbaum Scenario Exhibited by Thin Plate Dynamics

The dimensionless partial differential equations governing thedynamics of a thin flexible isotropic plate with an external load arederived and investigated. The period doubling bifurcations, as well asthe chaotic dynamics, are detected and analyzed. The algorithms leadingto the reduction of the original equations to those of a difference setof ordinary differential and algebraic equations are proposed, comparedto other known methods, and then applied to the problem.Among others, it is shown that, in spite of the system complexity, theFeigenbaum scenario exhibited by one-dimensional maps also governs theroute to chaos in the continuous system under consideration.     

Approximation and Reconstruction of the Electrostatic Field in Wire–Plate Precipitators by a Low-Order Model

The numerical computation of the ionic space charge and electric field produced by corona discharge in a wire–plate electrostatic precipitator (ESP) is considered. The electrostatic problem is defined by a reduced set of the Maxwell equations. Since self-consistent conditions at the wire and at the plate cannot be specified a priori, a time-consuming iterative numerical procedure is required. The efficiency of all numerical solvers of the reduced Maxwell equations depends in particular on the accuracy of the initial guess solution. The objectives of this work are two: first, we propose a semianalytical technique based on the Karhunen–Loève (KL) decomposition of the current density field J, which can significantly improve the performance of a numerical solver; second, we devise a procedure to reconstruct the complete electric field from a given J. The approximate solution of the current density field is based on the derivation of an analytical approximation , which, added to a linear combination of few KL basis functions, constitutes an accurate approximation of J. In the first place, this result is useful for optimization procedures of the current density field, which involve the computation of many different configurations. Second, we show that from the current density field we can obtain an accurate estimate for the complete electrostatic field which can be used to speed up the convergence of the iterative procedure of standard numerical solvers.     

波纹板式空冷器阻力与传热特性实验研究

在可改变风量和热水流量的实验条件下,对波纹板式空冷器的阻力与传热特性进行实验研究。得到了空气侧的阻力降关联式以及两侧的对流换热系数关联式,其适用于热水雷诺数在2000-8000之间、空气雷诺数在2000-10000之间。在相同工况下,比较了波纹板式、光管式和翅片管式空冷器的性能指标,结果表明:迎面风速在2.45-4.1 m/s之间,波纹板式空冷器传热系数达到100-160 W/m2/℃;约比光管式提高70%,但只有以管束外表面为基准的翅片管式传热系数的六分之一;板式空冷器单位体积换热量约是翅片管式空冷器的1.5倍,是光管式的15倍;板式空冷器单位功耗换热量约是光管式空冷器的5.5倍,而翅片管式空冷器与光管式空冷器则相差不大。     

物光的偏振性对全息记录质量的影响

通过对菲涅耳三维漫反射全息记录光路中物光与参考光偏振状态的实验检测，发现线偏振的激光被不同表面材料的物体散射和漫反射后变成“部分偏振光”，几乎所有目标物都有显著的消偏振现象，全息干板上实际记录的是线偏振的参考光与“部分偏振”的物光形成的相干度较低的干涉条纹。物光偏振度的大幅度下降影响干涉条纹的衬比度，并增加全息图的噪声。给出实验方案和检测光路，采用在参考光路中插入1/4波片的方法，可充分利用非偏振物光各个振动方向的光能，提高条纹的衬比度。     

Measurement Accuracy in Phase-Shifting Point Diffraction Interferometer with Two Optical Fibers

A phase-shifting point diffraction interferometer (PS/PDI) with point sources of two single mode optical fibers has been developed, which will be appropriate for the surface figure measurement of large aperture optics on a sub-nanometer scale. To reduce the measurement error factors, a fiber optic plate (FOP) is used as a projection plane for interference pattern. Errors caused by imperfection of optical alignment, such as position of point sources and tilt of FOP, are minimized by analyzing the measured phase data with an original method. Measurement accuracy in the PS/ PDI is estimated with the interference pattern produced by the two optical fiber sources. If inhomogeneity of the FOP and a systematic error of the PS/PDI are eliminated, the measurement accuracy of the present system is estimated to be less than 4nm P-V and 0.7nm rms, respectively, at a measurement wavelength of 632.8 nm.