New Model of Dusty Plasma Particles Interaction

The main goal of this report is to obtain the macropotentials of dusty plasma particles interactions which account for the collective events in the medium and, then, to analyze their dependence on plasma parameters. It is shown that the attraction between conductive dust grains turns possible due to the polarization phenomenon (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

半导体粒子CdS的光学性质研究

采用DDA(discrete dipole approximation)方法对用于光催化制氢的半导体粒子的光学性质进行了研究,讨论了形状、尺寸等因素对放置在水中的CdS吸收效率的影响,选取的粒子形状有球形,圆柱形,正四面体,正三棱柱,长方体,正六角棱柱,发现粒子形状对局部表面等离子体共振峰的数目和共振波长有重要影响,而...     

壳层纳米颗粒的光散射行为研究

本文主要研究了Au-Si球型壳层纳米颗粒在电磁波作用下的散射行为,并将其与实心Au球、空心Au球、实心Si球和空心Si球的光散射行为进行了对比。利用Mie散射理论计算得出Au-Si球型壳层纳米颗粒在外加电磁波作用下的各阶电响应和磁响应,观察壳层结构的几何参数对电偶和磁偶共振峰位置的影响,并进一步研究Au材料中的电偶响应与Si材料中的电偶(磁偶)响应之间的耦合关系,找到其中的耦合规律。通过对单个球型壳层纳米颗粒散射行为的研究,为利用该颗粒周期性排列制备具有特殊电磁性质的人工特异材料提供理论指导。     

PM2.5气溶胶光学特性研究

利用FA-3型Anderson撞击式气溶胶粒度分布采样器采集大气中的可吸入颗粒物。在实验室使用光学测量系统对粒径低于PM2.5的气溶胶颗粒物进行透过率测量。结果表明,透过率随气溶胶粒子粒径的增大具有逐渐增加的趋势。粒径低于PM2.5的气溶胶颗粒与PM10粒径范围内的透过率相比,具有明显的波长选择性。     

The Influence of TiC Particles on the Structure and Mechanical Properties of Ni3Al Manufactured By Spark Plasma Sintering

Russian Physics Journal - Using precursors, prepared by a preliminary mechanical activation of the 3Ni–Al powder mixture in the energy-intensive ball mills with and without a subsequent...     

孔隙率对气溶胶凝聚粒子光学特性的影响

采用Monte-Carlo方法,对气溶胶凝聚粒子进行了模拟,讨论了凝聚粒子的孔隙特性,分析了空间结构、原始粒子数目对凝聚粒子孔隙率和等效折射率的影响。结合物质的电结构,将气溶胶凝聚粒子离散为一系列偶极子,利用离散偶极子近似方法,数值计算了不同孔隙率气溶胶凝聚粒子的散射、吸收和消光截面各种取向的统计平均值。结果表明,气溶胶凝聚粒子的孔隙率明显取决于其空间形状和所含原始微粒的数目;气溶胶凝聚粒子的等效折射率、吸收、散射和消光截面则随孔隙率的增加而减小。研究结果可为全面理解气溶胶粒子光学特性提供参考;也可为某些涂层材料光学性能的改变提供参考,通过改变涂层材料中凝聚粒子的孔隙率来改变涂层材料的等效折射率,进而改变涂层材料对光的散射和吸收。     

CdS半导体超微粒样品光谱性质的研究

纳米尺度的半导体超微粒在线性和非线性光学方面表现出来的奇特性质使其成为研究和开发新的功能材料的热点。成键为 S、P轨道的 - 族金属硫化物半导体 ,电子结构和晶体结构均较为简单 ,结晶性能好 -界面无序结构少 ,在纳米尺度上其结构仍与体相材料近似 ,因此 ,成为研究量子尺寸效应的理想材料。本文对采用化学微乳液法合成的 Cd S半导体超微粒的光谱性质进行了研究 ,实验结果显示 ,Cd S超微粒样品的吸收光谱的带边与体相相比发生了蓝移 ;从吸收光谱中可以看到 ,Cd S超微粒样品的吸收边随粒径减少而向短波方向移动。拉曼光谱的电子—— L O声子耦合在粒子尺寸 2 .4- 2 .9nm范围内与粒子尺寸无关     

Plasma Oscillations and Their Influence on Certain Properties of Nonideal Plasma

The hypothesis is proposed that Langmuir plasma oscillations can exist in nonideal plasma inspite of great collisional frequency. This possibility is confirmed by numerical estimations and the results of several experiments. The influence of plasma oscillations on electron states density and conductivity of nonideal plasma is considered. The simple formula obtained for conductivity agrees well with available experimental data.     

Electrical and Optical Properties of High-Pressure Argon Plasma

Argon plasma has been investigated in the pressure range p ? 200 bar and at temperatures up to 13 000 K. The experiments were performed by using a wall-stabilized arc in an uncooled copper cascade. The measured electrical conductivity agrees with theoretical predictions based on the unified theory. Line and continuous intensities, as well as width and shift of the Ar I line at ? = 696.5 nm, were determined. A set of optimized atomic constants for these radiative processes was obtained by a newly developed multiple approximation method. While linewidth due to Stark and Van der Waals broadening are in fair agreement with theory, the line shift has to be corrected.     

激子-声子相互作用对三阶非线性光学性质的影响

在对激子不作任何近似的条件下,对强耦合激子声子系统中非线性光学性质在理论上进行了研究,结果表明当信号光场频率与激子频率的失谐量等于光学声子的频率时,系统的非线性光学吸收和克尔系数显著增大,从而证明了激子声子的强相互作用对介质的非线性光学性质的影响相当大。并且,与对激子作代松马利夫(Dyson-Maleev)变换近似和玻色近似的结果进行仔细的比较,发现对激子不作近似时,这种影响将进一步增大。     

Investigation an Effective Interaction Potential of Dust Particles in Nonideal Dusty Plasma

Interaction between dusty particles remains to be an interesting issue that still requires deeper theoretical and experimental investigations. In the present paper we formulate a theoretical approach to the calculation of effective interaction potential of dust particles on the basis of Poisson equation and experimentally measured pair correlation functions. By application of our model to the data from the liquid phase of dust formations in stratified dc glow discharge, it is shown that there is an attractive component in the interaction of dust particle (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Collective Electrostatic Interaction of Particles in a Complex Plasma with Ion Flow

Linearized electrostatic potential of a test charge in a complex (dusty) plasma with ion flow is found. Dust component is treated as a continuous medium. Positions of dust particles are assumed to be fixed (unperturbed by the test charge). Calculations are performed using the static dielectric response function found in the framework of the fluid model. The model includes ion loss and ion creation caused respectively by absorption on dust particles and ionization. Dust charge variations and friction force on ions (ion‐neutral and ion‐dust friction) are also present in the model. The main point of the paper is the potential distribution in the plane containing the test charge and oriented perpendicular to the ion flow. The possibility of the electrostatic attraction of two same sign charges in the plane perpendicular to the ion flow is investigated. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Pair Interaction Potential of Particles for Two‐Component Plasma

In this work the semiclassical potential for plasma particles pair interactions, which takes into account the diffraction effects due to the uncertainty principle in two‐component plasma (the region of temperatures 10⁴K < T < 10⁸K and densities 10²¹cm^–3 < n ≤ 10²⁴cm^–3), was proposed. The values of this potential were numerically calculated and an interpolation formula was obtained (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Influence of Non-Maxwellian Particles on Dust Acoustic Waves in a Dusty Magnetized Plasma

In this paper an investigation into dust acoustic solitary waves(DASWs) in the presence of superthermal electrons and ions in a magnetized plasma with cold dust grains and trapped electrons is discussed. The dynamic of both electrons and ions is simulated by the generalized Lorentzian(κ) distribution function(DF). The dust grains are cold and their dynamics are studied by hydrodynamic equations. The basic set of fluid equations is reduced to modified Korteweg-de Vries(mKdV) equation using Reductive Perturbation Theory(RPT). Two types of solitary waves, fast and slow dust acoustic soliton(DAS) exist in this plasma. Calculations reveal that compressive solitary structures are possibly propagated in the plasma where dust grains are negatively(or positively) charged. The properties of DASs are also investigated numerically.     

渤海近岸水体悬浮颗粒物对后向散射特性的影响研究

进行海洋水体悬浮颗粒物的空间分布及粒径构成对后向散射特性变化影响,研究对于加深水体散射性质的认识、提高水色遥感反演参数的精度及海洋环境监测等具有重要意义。结合渤海海域2017年6月、9月的现场数据,获得了夏季、秋季各站位总悬浮颗粒物浓度(SPM)、颗粒粒径以及后向散射系数等参数并进行研究。结果表明,后向散射系数b_bp在可见光波段随波长的增加而减小;同时,夏季和秋季,大多数站位b_bp(550)的变化趋势与SPM的变化趋势基本一致;在进行两者之间的相关性研究时发现,相关系数R2并不高,仅为0.24。该研究还建立了平均粒径(D_A)、中值粒径(D₅₀)与b_bp的关系,得出D_A与b_bp呈线性关系,受季节及水体颗粒构成的影响,夏季,水体颗粒物以小颗粒为主,两者之间的相关性高于秋季,两个季节的R2分别为0.7和0.3;同时得出当水体以小颗粒为主时,b_bp随D_A增大而增大,以大颗粒为主的时,b_bp随D_A增大而减小。D₅₀与b_bp的关系则不同,两者之间呈现非常好的幂指数关系,在同一季节里,b_bp均随着D₅₀的增大而减小,即水体中颗粒物粒径越小,其后向散射系数越大,夏季和秋季两者之间的相关系数分别为0.66和0.5;并且发现如果不分季节差异,现场水体颗粒物的粒径构成对b_bp的影响很难确定。     

基于光学闭合原理的太湖水体颗粒物后向散射特性模拟

后向散射系数是遥感传感器获取水体信息的来源,也是生物光学模型的重要输入参数。利用太湖春季和秋季实测数据,在生物光学模型的基础上结合光学闭合原理模拟了太湖春、秋季节水体颗粒物后向散射系数,进而分析了其光谱特性及颗粒物后向散射概率的时空变化。结果表明,太湖春、秋季节水体颗粒物后向散射系数与总悬浮物、无机悬浮物浓度均具有较高的相关性,而与有机悬浮物浓度的相关性则相对较低,颗粒物后向散射系数随波长变化指数n在太湖春季水体中的变化范围为0.66～1.84,平均值为1.29±0.25,而在太湖秋季水体中的变化范围为0.67～2.40,平均值为1.24±0.34;太湖春季水体颗粒物平均后向散射概率为0.030,而太湖秋季水体颗粒物平均后向散射概率为0.031,且无论是太湖春季水体还是太湖秋季水体,其颗粒物后向散射概率的波长依赖性均较弱。模拟吸收系数与实测吸收系数吻合较好,总体的平均相对误差均在18%以内。     

Influence of Defect Particles on Configuration of a Two-Dimensionally Confined Dusty Plasma

The behaviour of defect particles in a two-dimensional （2D） confined dusty plasma system is investigated by molecular dynamics （MD） simulations. The mean square displacement （MSD） and the pair correlation function g（r） are used to characterize the structural and dynamical properties of the system. The influences of the number and the charge （mass） of the defect particles on the system configurations are simulated. All the defect particles with charges （masses） larger than the normal particles have the trend to move towards the system centre. The moving speed of the defect particles towards the centre increases with the increasing number and charge （mass） of defect particles and with the system temperature.     

基于主动差分吸收光谱系统获取大气颗粒物光学特性研究

以主动差分吸收光谱遥感技术为基础,在干净大气环境条件下,结合参考光路设计技术,开展了获取近地面气溶胶颗粒物的光谱新方法研究.针对以宽带氙弧灯为光源的主动差分吸收光谱系统固有宽波段特性,建立了解析颗粒物光学厚度模型,获取了大气颗粒物光学特性.最后通过外场实验,获得测量期间气溶胶颗粒物光学厚度,然后采用对数线性回归获取Angstrom波长指数和混浊系数,以及大气能见度数据.主动差分吸收光谱系统用测量光程范围内的大气总的吸收特性,获得监测区域的颗粒物平均水平,更具有代表性和进一步应用价值.     

Influence of Solvent-Solvent and Solute-Solvent Interaction Properties on Solvent-Mediated Potential

A recently proposed universal calculational recipe for solvent-mediated potential is applied to calculate excess potential of mean force between two large Lennard-Jones （LJ） or hard core attractive Yukawa particles immersed in small LJ solvent bath at supercritical state. Comparison between the present prediction with a hypernetted chain approximation adopted for solute-solute correlation at infinitely dilute limit and existing simulation data shows high accuracy for the region with large separation, and qualitative reliability for the solute particle contact region. The calculational simplicity of the present recipe allows for a detailed investigation on the effect of the solute-solvent and solvent-solvent interaction details on the excess potential of mean force. The resultant conclusion is that gathering of solvent particles near a solute particle leads to repulsive excess PMF, while depletion of solvent particles away from the solute particle leads to attractive excess PMF, and minor change of the solvent-solvent interaction range has large influence on the excess PMF.