Phase-conjugate resonant holographic interferometry applied to NH concentration measurements in a two-dimensional diffusion flame

Resonant holographic interferometry is a diagnostic technique based on the dispersion of light having a frequency close to that of an electronic transition of a molecule. We propose a novel single-laser, two-color setup for the recording of resonant holograms and apply it to two-dimensional (2D) species concentration measurements in a combustion environment. The generation of the second color is achieved by optical phase conjugation from stimulated Brillouin scattering in a cell. The frequency shift of ~8.5 GHz introduced by the phase conjugation matches approximately the linewidth of many molecular transitions at typical flame temperatures and can be implemented to produce holograms of good contrast and diffraction efficiency. Phase-conjugate resonant holographic interferometry is demonstrated in a 2D NH(3) -O(2) flame, yielding interferograms containing information on the NH radical concentration distribution in the flame. Experimental results are quantified by application of a numerical computation of the complex refractive index.     

Coherent anti-Stokes Raman scattering measurements of N(2)(X, v) at low pressures corrected for stimulated Raman scattering

Number density measurements of the populations of the vibrational states of the electronic ground state of molecules that use scanning coherent anti-Stokes Raman scattering (CARS) spectroscopy at pressures in which Doppler broadening dominates can be strongly influenced by population changes caused by the stimulated Raman process. Such measurements have been carried out in heterogeneous deactivation studies of vibrationally excited N(2) on various solid surfaces at 17 Torr. This process perturbs the populations of the states connected by the incident fields. It typically reduces the population difference and therefore reduces the observed CARS signal. Thus, as the incident laser irradiance increases, the observed signal exhibits saturation. A linear relationship for this effect in terms of the average laser powers is derived, providing a scheme for calibrating the initial onset of this saturation process. This calibration method permits simple corrections of the CARS data for saturation.     

Basic image-processing operations by use of acousto-optics

We describe some basic optical image-processing operations with acousto-optic (AO) Bragg diffraction. Instead of using frequency-plane filters, we place an AO cell behind the object. We then realize experimentally one-dimensional edge enhancement, which utilizes a high-pass filtering effect in the undiffracted order from the AO cell. A numerical simulation compares well with the experimental results. With two AO cells oriented orthogonally to each other, a second-order mixed derivative operation, evident from the four-corner enhancement of a square, is also demonstrated.     

Time-resolved polarization shadowgrams in turbid media

The use of the polarization of light as a parameter to discriminate against multiple-scattered light for transillumination imaging through random scattering media is examined. Time-resolved two-dimensional images of submillimeter test bars immersed in 5-cm-thick Intralipid solutions with different micelle dilutions were measured for two orthogonal polarizations (parallel and perpendicular) of light emerging from the turbid medium by using a picosecond Kerr-Fourier (KF) imaging system. The measured contrast and intensity of parallel-polarized KF shadowgrams decreased as the concentration of the scattering medium was increased, whereas the behavior of the perpendicular-polarized KF shadowgrams varied in an opposite matter to the micelle concentration.     

基于Logistic回归的上市公司财务预警模型构建

通过一定的财务指标,采用我国上市公司的财务数据,基于Logistic回归方法构建上市公司财务危机预警的模型,经过检验,具有一定的实际应用价值。     

电生成Fenton试剂对刚果红染料废水处理的研究

研究了电生成Fenton试剂对刚果红染料模拟废水的降解脱色.实验发现:本系统能有效降解刚果红染料废水,通过测定处理前后系统的紫外-可见光谱、红外光谱、CODCr等方法考察了本体系对刚果红染料降解的效果,结果表明在处理50 min后刚果红废水的脱色率可达到95%以上,CODCr的去除率达到85%以上.     

超高水头大型船闸输水系统研究

随着社会经济的发展和技术的提高,船闸不断向大型化和高水头化方向发展,以往常规的等惯性输水系统已不能适应40 m以上的超高水头大型单级船闸。结合某工程实例,通过类比分析、物理模型试验及数值计算的方法,提出了新型自分流的闸室分流口结构型式和输水系统布置型式,很好地解决了闸室高效输水和船舶停泊安全问题,显著拓展了常规等惯性输水系统的适应性,其成果可供超高水头大型船闸设计借鉴。     

F—T合成蜡的表征和改质项目的概况

F-T法是一种经过工业考验的,由煤间接液化获得馏份油产物的方法.这项工艺过程,使来自煤气化炉的合成气被转化成运输燃料和副产品一一低碳烃气体和蜡.实际的产率和产品特性与F-T反应器的结构和操作条件有关.本合同项目的目的是用工业上可行的、经济的加工方法,使F-T法生产的可销售的馏份燃料油的产率最大.按此要求,UOP研究了几种F-T     

Delphi6的新锐体验——读刘艺老师的新作《Delphi6企业级解决方案及应用剖析》

Delphi6的正式发布差不多已经快一年了。市面上名目繁多的Delphi6的图书令人眼花缭乱,然而要找一本像李维《Delphi6/Kylix2 SOAP/Web Service程序设计篇》那样的有价值的Delphi6书仍然不是一件太容易的事。因为大多数自称是Delphi6的书并没有正真介绍属于Delphi6的新技术、新思想。准确地讲,虽然那些过时的东西在Delphi6中也能跑,但它们还是停留在Delphi5甚至Oelphi4的思想、方法和内容上,让人很难体验到Delphi6带来的新感觉。     

Thirty years of observing and documenting sky optical phenomena

A homogeneous series of systematic observations of sky optical phenomena in the Netherlands has been gathered by the Dutch Observing Network since 1965. This continues the Dutch observation series that started at the end of the nineteenth century. A time series of ice-crystal halo frequencies from 1920 to 1996 and frequency diagrams of some specific halos the period from 1970 to 1996 are shown and discussed. Systematic observation recording by means of diaries and exchanging routines among observers are described. Methods are given for establishing and maintaining a network of volunteers that can provide, in a homogeneous time series, sky optical phenomena recordings.