Effect of the dependence of the specular reflectance on the angle of incidence of electrons on the impedance

We obtain the solution to the problem of the skin effect in a metal with specular-diffusion boundary conditions for arbitrary values of the anomaly parameter in the form of the Neumann series. For this purpose, we develop a method based on the idea of representation of not only the boundary condition imposed on the field (as is conventionally done), but also the boundary condition imposed on the distribution function, in the form of a source. The specular reflectance is an arbitrary function of the angle of incidence of electrons on the metal surface.     

Modelling of the Effect of the Sheared Poloidal Flow on the Electrostatic Turbulence on the CASTOR Tokamak

Electrostatic drift turbulence of the edge plasma in the CASTOR tokamak is studied numerically by using the Hasegawa-Wakatani equations. The fluctuations of plasma density and potential as well as the corresponding fluctuation-induced particle flux are calculated for regimes with various plasma poloidal flows. Results of numerical simulations are in a reasonable agreement with experimental results.     

工作压力对热声驱动阻容负载性能影响的实验研究

进行了热声发动机驱动阻容负载的实验研究;讨论了工作压力对热声驱动阻容负载性能的影响。随着平均工作压力的增大,负载入口处压力振幅和输出的声功率都明显增大,同时板叠热端温度有较大幅度下降,有利于低品位热源的利用和提高系统相对卡诺效率。     

A note on the conformal quasi-invariance of the Laplacian on a pseudo-Riemannian manifold

We consider the Laplacian on a pseudo-Riemannian manifold with constant scalar curvature (e.g. Euclidian space with an arbitrary signed inner product or its conformal compactification and coverings of this) and show that for this minus a constant we have quasi-invariance with respect to an action of the conformal group on functions.     

银纳米颗粒对胆固醇荧光的增强效用研究

在传统荧光光谱技术的基础上,结合金属纳米颗粒的增强荧光技术,探索提高荧光光谱技术检测人全血溶液中胆固醇含量的精度和分辨率的方法。实验研究方面,采用波长为407 nm的激光作为激发光,照射加入一定量银纳米颗粒作为荧光增强剂的人全血溶液,研究了银纳米颗粒对人全血溶液在可见光波段的荧光增强作用。结果表明,胶体状态的银纳米颗粒可以显著增强低浓度的人全血溶液荧光光谱的强度,且不同位置荧光发射峰的荧光增强效率随银胶加入量的增加均呈现先增后减的趋势,但不同峰位置的最强增强效率对应的银胶加入量不同。理论分析方面,根据实验结果及胆固醇分子和银纳米颗粒在溶液中的分布情况,建立了分子间距模型,并根据模型计算得出胆固醇分子和银纳米粒子之间的最佳增强荧光效果间距在12.19～25 nm范围内,这个结果和其他文献中的理论值吻合较好。综上所述,使用银纳米颗粒可实现全血溶液荧光的增强,研究结果为提高检测血液中多种物质的灵敏度和精度提供了有价值的参考作用。     

基于四叉树的光学小波滤波器轴心定位的研究

精度问题制约了光学小波变换的广泛应用。若要扩展其应用领域,必须提高变换精度。在二维光学小波变换4f系统中,小波滤波器轴心的精确定位至关重要。提出了一种基于四叉树搜索方法的光学小波滤波器轴心定位方法。所用的加载滤波器载体为空间光调制器(SLM),定位精度可达到SLM的一个像素大小。为加快搜索速度,提出了一种基于四灰度级并行处理的改进方法。     

基于自洽输运理论的介观体系动态电导的研究

基于介观体系电子动态输运的自洽理论,讨论了介观结构的动态电导.作为该理论的应用,采用一介观相干平行板电容器模型来进行研究. 结果表明:体系的动态电导与外场频率和体系费米能有关,为一复数且有有限虚部. 当外场频率较小时,动态电导随费米能的变化所呈现的特性和直流情形非常相似,但是随着外场频率的增加,两者差异就变得非常明显,体系动态电导随外场频率的变化呈现一些峰值结构. 在给定体系费米能时,动态电导随着外场频率的变化而产生振荡,并且出现了负的电导虚部,电导虚部的正负表明了体系的电容特性和电感特性. 关键词： 自洽输运理论 相干平行板电容器 电导 介观体系     

耦合孔对微波腔的影响研究

从Maxwell方程出发,将微波腔中的实际微波场按其本征模式展开,进行微波腔的工作特性(如工作频率、场分布等)的研究.在具体处理过程中,根据复杂结构微波腔的具体边界,将微波腔分成规则形状微波腔和非规则(含耦合孔)部分,建立实际微波腔模式同规则形状微波腔模式之间的场耦合方程,从而确定耦合孔对微波腔模式的影响,并对开耦合孔的圆柱腔进行了相应的理论和模拟研究. 关键词： 微波腔 模式 场耦合 圆柱微波腔     

Influence of the polarisation of the medium on the radiation of channeled particles

The theory of the electromagnetic radiation from channeled particles is developed with inclusion of a virtual photon interaction with the crystal. Simple estimates are made for the spectral and angular distribution of the radiation. It is shown that the polarisation of the medium may lead to a drastic shrinking of the frequency range allowed for the radiation. The possibility of an increase of the transverse energy of a particle caused by radiation is predicted.     

On the influence of the trapping of particles on the beam-plasma interaction

Interaction of the trapped beam particles with spectrum is discussed in the paper. In models of particles in two waves and in a spectrum (with given amplitudes) we discuss partly well trapped particles (in the region of harmonic oscillations), partly weakly trapped particles near the separatrix; further, we discuss the range of resonances, the transport of energy and a possibility of transition of the trapped beam into the quasiergodic state. For the case of a discrete spectrum, conditions for the beam diffusion are given and, within the framework of system with mixing, conditions for existence of hf field-beam particles balance are discussed.Nademlýnská 600, Praha 9, Czechoslovakia.     

Existence of temperature on the nanoscale

We consider a regular chain of quantum particles with nearest neighbor interactions in a canonical state with temperature T. We analyze the conditions under which the state factors into a product of canonical density matrices with respect to groups of n particles each and under which these groups have the same temperature T. In quantum mechanics the minimum group size n(min) depends on the temperature T, contrary to the classical case. We apply our analysis to a harmonic chain and find that n(min)=const for temperatures above the Debye temperature and n(min) proportional to T(-3) below.     

微型投影机光学引擎的研究

设计了一种针对个人用户使用的微型投影机光学引擎,系统为单片式数字光线处理器结构,采用红绿蓝三色大功率高亮度发光二极管作为光源,使用X棱镜作为合色元件,从而实现38.1～50.8 cm的彩色投影显示.对设计结果进行理论分析后可知,设计结果满足投影显示对颜色的要求,光学引擎的理论效率为16.1%.同时利用Light Tools仿真软件对系统进行建模分析,300万条光线追迹仿真的结果表明,光学引擎的效率为14.6%,与理论分析结果基本符合,屏幕上光通量为22.8 lm,其美国国家标准协会规定的九点照度均匀性达到91.55%和-93.36%,满足设计要求.     

栅极热变形对离子推力器工作过程影响分析

栅极热变形是影响离子推力器性能和寿命的重要因素. 采用三维粒子方法对栅极系统等离子体输运过程进行模拟, 对比、分析栅极热变形前后栅极系统的电子返流限制、导流系数限制、离子通过率和发散角损失. 结果表明: 栅极热变形增大了屏栅离子通过率和推力器推力值, 并由于加速栅截止电流阈值的提高拓展了推力器工作电流区间, 但电子返流阈值的明显降低对栅极系统可靠工作造成了不利影响.     

Effect of sulfide pollution on the stability of the protective film of benzotriazole on copper

Benzotriazole (BTAH) is an excellent inhibitor for the corrosion of copper and many of its alloys in unpolluted media. Protection is attributed to the formation of a film of Cu(I)BTA. Injection of sulfide ions into a benzotriazole inhibited salt water damages the protective Cu(I)BTA film very rapidly, increases the corrosion rate and leads to the formation of copper sulfide. This effect is quite marked at a sulfide concentration as low as 10⁻⁵ M (about 0.3 ppm sulfur) in the presence of 10⁻² M BTAH, which is 1000-fold greater than that of the sulfide ion. The intensity of sulfide attack increases with its concentration.Prolonged pre-passivation of copper in the BTAH protected medium even at high concentration does not markedly improve the resistance of the protective film to sulfide attack. This finding is contrary to a well-documented phenomenon in unpolluted media where the inhibiting efficiency of BTAH increases with the time of immersion and the concentration of the inhibitor. X-ray photoelectron spectroscopy (XPS) reveals the presence of both sulfide and BTAH on the corroded surface indicating that sulfide attack is localized.     

Influence of the Elastic Base of a Basin on the Propagation of Waves on the Water Surface

A layer of an ideal liquid located on an elastic half-space (with a flat unperturbed boundary) is considered in the linear approximation. At the zero time moment, a localized perturbation of the displacement vector occurs in the elastic half-space, and this perturbation, after some time, leads to a modification (perturbation) of the interface between the water and the crust, which, in turn, leads to a localized perturbation on the surface of the liquid and to the occurrence of surface waves. We are interested in the following question: to what extent does getting rid of the stiffness of the bottom and replacing it by an elastic base influence the speed of propagation of the front of the long wave and its profile under the assumption that the initial perturbation is given immediately on the free surface of the liquid?     

A note on the fragmentation functions of discrete particles on the Artru-Mennessier string

The Artru-Mennessier model for the breakup of strings of colour connecting partons yields a continuous hadron spectrum. I show how the same physical picture may be implemented with a spectrum of discrete hadrons, the Artru-Mennessier model being recovered in the limit of a dense spectrum. As in the Artru-Mennessier model, fragmentation functions are mass dependent and heavy hadrons are dynamically suppressed relative to lighter.     

Influence of cosmic rays on biomarkers on the mars

Detection of the organic substance on the Mars is one of the main targets of the current and future Martian landing missions. In this study, we calculated the ionization of the Martian soil by solar and Galactic cosmic rays at its various depths. It is shown that complex organic molecules (biomarkers) with a mass more than 300 a.m.u. at a depth of ≤10 cm degrade for a time less than one milliard years.     

基流对热对流涡旋结构影响的实验结果初步分析

用实验室模拟方法研究了径向温度梯度对热对流涡旋的影响,结果表明,径向温度梯度所引起的基流使热对流涡旋的对称性结构被破坏,使涡旋变成非对称结构,并使涡旋向基流下游偏移,其强度随基流的加强而减弱,直至消失.热对流涡旋越强其对称性结构越稳定,基流对它的影响越小 关键词： 转盘实验 基流 热对流涡旋     

Effect of epistasis on the evolution of the quasi-species model

Epistasis is a phenomenon of non-additive interactions between genes in determining phenotypes. We investigate how epistasis affects the evolution of the quasi-species model by using the parallel mutation-selection (ParaMuSe) quasi-species evolution model. From the stochastic simulation of the ParaMuSe model, we find that there is a transition between the quasi-species with negative magnetization and the quasi-species with positive magnetization, depending on the peak value of each fitness region. The critical peak value for the transition is found to be larger than the equalpeak case so that even with a higher peak in the positive epistatic region, the quasi-species can be formed in the negative epistatic region. We analyze simulation results by using the coherent state representation for the ParaMuSe model and find that negative epistasis is favored to positive epistasis in forming more diverse quasi-species.

     

光谱法研究变性剂对苦荞麦蛋白质构象的影响

采用紫外差示光谱和荧光光谱研究了不同浓度的乙醇溶液和盐酸胍溶液对苦荞麦蛋白质(TBWSP31)构象变化的影响.研究表明,TBWSP31的色氨酸残基和酪氨酸残基有的位于分子内部,有的暴露于分子表面.乙醇溶液使TBWSP31变性时,仅仅是分子的外层结构发生了变化,分子内部疏水核的变化较小,高浓度的盐酸胍使位于TBWSP31...