A delta-function method for the n-th approximation of relaxation or retardation time spectrum from dynamic data

A function series g(x; n, m) is presented that converges in the limiting case n and m = constant to the delta-function located at x = = 1. For every finite n, there exists 2n+1(–nmn) approximations of the delta-function _(n)(x–x _n,m ). x _n,m is the argument where the function reaches its maximum. A formula for the calculation is given.The delta-function approximation is the starting point for the approximative determination of the logarithmic density function of the relaxation or retardation time spectrum. The n-th approximation of density functions based on components of the complex modulus (G*) or the complex compliance (J*) is given. It represents an easy differential operator of order n.This approach generalizes the results obtained by Schwarzl and Staverman, and Tschoegl. The symmetry properties of the approximations are explained by the symmetry properties of the function g(x; n, m). Therefore, the separate equations for each approximation given by Tschoegl can be subsumed in a single equation for G and G, and in another for J and J.     

Phase Interaction in a Vapor-Liquid Medium in Transient Flow Regimes

A mathematical model and a numerical method are developed for studying nonlinear wave processes in two-phase liquids with gas or vapor bubbles under conditions of impact interaction with deformable media. On the basis of the proposed approach to the numerical modeling of the dynamics of the transient processes in the two-phase vapor-liquid and deformable media, the basic features of the phase behavior, the phase transitions, and the interphase heat and mass transfer, typical of liquids containing vapor bubbles, are analyzed. The results of solving problems of the dynamics of different vapor-liquid media are presented.__________Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, 2005, pp. 88–102.Original Russian Text Copyright © 2005 by Petushkov.     

激光通过散射介质的聚焦

基于角谱衍射公式和散射介质的圆形高斯分布模型,数值模拟光通过散射介质的聚焦.通过反馈优化算法实现散射光束的波前整形,在目标位置处形成一个很亮的聚焦光斑.改变聚焦目标位置后,可实现任意位置处的单点或多点聚焦.讨论了空间光调制器上的总调制单元个数、每个调制单元相位准确度与光强增长因子的关系.结果表明:目标位置处的光强随着总像素单元数的增加而线性地增强,并且随着调制单元的相位准确度的增加而增强.     

用Matlab比较双缝干涉和双缝衍射

运用Matlab软件,对双缝衍射和双缝干涉、单缝衍射的光强分布和谱线特征进行了数值模拟,绘出实验中难以观察到的光强分布图,比较出双缝衍射与双缝干涉及单缝衍射的联系与区别。     

Conformational stability and vibrational study of phenylacetyl chloride

The Fourier transform infrared spectroscopy and Fourier transform Raman spectra of phenylacetyl chloride were recorded and analyzed in the range 3500–400 and 3500–200 cm^?1 at room temperature, respectively. In order to obtain the structural information and conformational stabilities, a potential energy surface scan for internal rotation was carried out at the B3LYP/6‐31G(d) level. The potential energy surface reveals that the title compound has two minimal conformers (A and B). The optimized geometries, structural parameters, stabilities, energies, thermodynamic parameters, vibrational wavenumbers, infrared intensities, and Raman activities for the two conformers (A and B) have been obtained by employing B3LYP and MP2 calculations with 6‐311++G (d, p) basis sets. The conformational energy difference between A and B is very small, indicating that the B conformer coexists with the A conformer. The detailed vibrational assignments of vibrational spectra of each conformer have been made on the basis of the potential energy distributions analysis. The highest occupied molecular orbital –lowest unoccupied molecular orbital energy gap and molecular electrostatic potential of the two conformers have been also calculated for comparison of their chemical activities. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of marine atmospheric turbulence effects on infrared imaging system by angle of arrival fluctuations

For the long-range infrared imaging system, the marine atmospheric turbulence degrades seriously the probability of object recognition and tracking. In this study, the angle of arrival fluctuations of an optical wave, which describes the distortion effects of marine atmospheric turbulence on an infrared optical imaging system, is investigated in detail both analytically and numerically. Analytic expressions of the angle of arrival fluctuations are derived for optical plane and spherical waves propagating through weak marine atmospheric turbulence with horizontal path, and they consider simultaneously finite turbulence inner scale, turbulence outer scale, wavelength, and aperture diameters. Numerical calculations are conducted to analyze the influence of marine weak turbulence on the infrared imaging. The results are useful for understanding the potential impact of deviations from the terrestrial turbulence.     

纳米磁流体动态散斑干涉场的奇异场分布

通过对由纳米磁流体运动引起的双扫描激光散斑干涉光场及其变化做拉盖尔-高斯滤波下的傅里叶变换,获得动态散斑干涉图对应的光学涡旋分布及变化特征。分析认为,光学涡旋分布及变化对应着由纳米磁微粒及其团族的运动所引起的动态散斑变化。当纳米磁微粒聚集到分散的过程中,动态激光散斑光场的奇异场分布发生相应变化,说明了磁流体运动过程对应涡旋密度有先大后小,再由小变大的两个变化;并且光学涡旋密度高,对应较小颗粒的散斑场,磁流体处于稳态的状况;光学涡旋密度低,对应较大颗粒的散斑场,对应着磁流体激烈的运动。研究结果体现了奇异场分布变化和纳米磁流体动后趋稳的过程存在对应关系。     

实用型三谱段太阳模拟器的设计与研制

本文设计并研制了一种实用型三谱段太阳模拟器,其光谱匹配可同时调整3个谱段(300~700 nm,700~900 nm,900~1 700 nm)范围的能量,修正后可满足三结砷化镓太阳电池的测试使用要求。本文重点阐述了三谱段太阳模拟器滤光片的设计和氙灯光谱的修正及测试,介绍了太阳模拟器的光机结构。实验表明:三谱段太阳模拟器的光谱匹配满足三结砷化镓太阳电池各子电池的响应电流值。在有效辐照面150 mm×150 mm上,平均辐照度可以达到2个太阳常数(2 730 W/m²),辐照不均匀度达到±1.77%,辐照不稳定度达到±0.83%,为太阳电池自动分拣系统提供了可靠稳定的平台。     

Bayesian inference on isospin splitting of nucleon effective mass from giant resonances in ~(208)Pb

From a Bayesian analysis of the electric dipole polarizability,the constrained energy of isovector giant dipole resonance,the peak energy of isocalar giant quadrupole resonance,and the constrained energy of isocalar giant monopole resonance in ~(208)Pb,we extract the iso scalar and isovector effective masses in nuclear matter at saturation density p_0 as m_(s,0)~*/m=0.87_(-0.04)~(+0.04) and m_(v,0)~*/m=0.78_(-0.05)~(+0.06),respectively,at 90% confidence level.The constraints obtained on m_(s,0)~* and m_(v,0)~* lead to a positive iso spin splitting of nucleon effective mass in asymmetric nuclear matter of iso spin asymmetry δ at p_0 as m_(n-p)~*/m=(0.20_(-0.14)~(+0.15))δ.In addition,the symmetry energy at the subsaturation density p~*=0.05 fm~(-3) is determined to be E_(sym)(p~*)=16.7±1.3 MeV at 90% confidence level.     

Small shower CORSIKA simulations

Extensive Air Showers (EAS) induced by cosmic ray particles of very low energies, owing to the significantly steep cosmic ray energy spectrum, dominate the secondary particle flux measured by single detectors and small shower arrays. Such arrays connected in extended networks can be used to determine potentially interesting spatial correlations between showers, which may shed new light on the nature of ultra high-energy cosmic rays. The quantitative interpretation of showers recorded by small local arrays requires a methodology that differs from that used by ordinary large EAS arrays operating in the "knee" region and above. We present "small EAS generator," a semi-analytical method for integrating cosmic ray spectra over energies of interest and summing over the mass spectra of primary nuclei in arbitrary detector configurations. Furthermore, we provide results on the EAS electron and muon fluxes and particle density spectra.