一种由自由电子能带模型计算费米能级的方法

对面心立方（fcc)、体心立方（bcc)和六角密堆积（hcp)三种不同结构的晶体,在假设它们的原胞中包含8个价电子并将价电子近似为自由电子的情况下,采用“自由电子气理论”和“自由电子能带模型”,研究其根据费米球确定的费米能级EF与根据自由电子能带模型计算的平均键能Em。研究结果表明,由自由电子能带模型计算所得3种不同结构晶体（因而电子密度也不一样）的平均键能Em等于各自自由电子系统的费米能级EF。平均键能Em是我们在异质结带阶理论计算中建议的一种参考能级,研究结果在深化对平均键能Em物理实质认识的同时,提供了一种借助于自由电子能带模型计算自由电子系统费米能级EF的新方法。     

炉内两相流动和煤粉燃烧的双流体-轨道模型

本文首次用双流体一轨道（连续介质－轨道ＣＴ）模型对大尺寸四角喷燃炉内气粒两相流动及煤粉燃烧进行了模拟。该模型基于欧拉气相方程组、欧拉颗粒连续方程和动量方程以及拉氏颗粒能量和质量变化的方程,对各子模型用ｋ－ε－ｋｐ两相湍流模型,ＥＢＵ－Ａｒｒｈｅｎｉｕｓ湍流燃烧模型,煤粉颗粒的水分蒸发,热解挥发和焦炭燃烧的扩散－动力模型,ＤＯ（离散坐标）辐射模型。采用了将坐标扭转一定角度的方法减小入口射流和网格斜交造成的伪扩散。编制了ＬＥＡＧＡＰ－ＦＵＲＮＡＣＥ－３程序,分别对冷态模型炉内两相流动和大尺寸炉内三维两相流动和煤粉燃烧进行了模拟,并与颗粒轨道（ＳＴ）模型的模拟结果进行了对照。采用ＰＤＰＡ对冷态模型炉内气粒两相流场进行了测量。冷态两相流动的模拟与实验结果的对比表明ＣＴ模型的模拟结果和实验符合较好,ＳＴ模型所得颗粒浓度分布和实验山入较大。热态模拟的结果给出了两相速度,气相温度,组分浓度和壁面热流分布。模拟结果定性合理。模拟结果显示在出口处由于气流旋转,有一局部高温区存在。     

反应堆核泵浦激光He-Ar-Xe体系泵浦效率理论研究

 系统地提出了He-Ar-Xe核泵浦激光泵浦效率的理论模型,推导了泵浦效率公式。研究了激光泵浦效率与泵浦腔内气体总压力, He和Ar分压,Xe的含量之间的函数关系。并用前人的实验结果定性地对模型进行了验证,拟合了泵浦效率函数参数,探讨了各参数之间的关系及其对泵浦效率的影响,为进一步的实验设计提供了理论依据。     

An overview on available models and techniques for the multicriteria reliability problem with emphasis on a potential use in a DSS for this problem type

The paper reviews available models and techniques covering three classes of the multi-criteria reliability problem. These classes include allocation of reliabilities in presence of multiple goals, reliability optimization with several kinds of failures and allocation of resources to optimize multiattribute systems. Optimization techniques are also suggested. The models and techniques are also evaluated with respect to their potential use in a DSS for reliability optimization.     

Stochastic flows on a countable set: Convergence in distribution

Consider a sequenceF ₁,F ₂,... of i.i.d. random transformations from a countable setV toV. Such a sequence describes a discrete-time stochastic flow onV, in which the position at timen of a particle that started at sitex isM _n(x), whereM _n =F _n F _n–1 F ₁. We give conditions on the law ofF ₁ for the sequence (M _n) to be tight, and describe the possible limiting law. an example called the block charge model is introduced. The results can be formulated as a statement about the convergence in distribution of products of infinite-dimensional random stochastic matrices. In practical terms, they describe the possible equilibria for random motions of systems of particles on a countable set, without births or deaths, where each site may be occupied by any number of particles, and all particles at a particular site move together.     

高能π–p碰撞J/ψ+γ硬衍射产生

用I–S模型与夸克偶素的色八重态产生机制,对πp碰撞J/ψ+γ协同产生的单衍射过程的微分截面及总截面进行计算,结果表明,把J/ψ+γ协同产生的单衍射过程和单举过程相结合,可以探测Pomeron中的胶子成分并对硬衍射因子化进行检验.     

A model for the problem of ground vibration induced by the wheels of a moving train

This paper presents a three-dimensional model for the analysis of ground vibrations excited by forces transmitted to the ground from the wheels of a moving train through the track. The field equations are solved by using scalar wave functions. From the computed results presented here, certain qualitative conclusions can be made to enhance our understanding of the physical problem.     

时分复用信号中的全光时钟提取实验

利用非均匀复用后的时分复用 (OTDM)信号 ,从 4× 2 .5GHz的时分复用光脉冲信号中直接提取出复用前的2 5GHz分路时钟信号。此技术可用于高速率时分复用光纤通信系统的解复用中的时钟提取。     

基于等效密度流体模型的地声参数分析

目前的地声参数反演多采用液态海底模型,但是实际海底为多孔弹性海底。该文在等效密度流体模型基础上,通过计算液态海底和多孔弹性海底的反射系数及传播损失,给出了等效密度流体模型和液态海底模型的等效性分析。数值仿真结果表明在低频情况下,多孔弹性海底给出的快纵波声速与等效密度流体模型给出的声速以及等效密度流体的实部与真实的海底密度基本一致。将等效密度流体模型近似看作液态海底模型进行反射系数和传播损失计算,在小掠射角和远距离时,计算结果表明与多孔弹性海底计算结果具有较好一致性,从而以此为依据确定海底为液态,进行地声参数反演。     

Deuteron electromagnetic form factors and tensor polarization observables in the framework of the hard-wall AdS/QCD model

We study the electromagnetic form factors and tensor polarization observables of the deuteron in the framework of the hard-wall AdS/QCD model. We find a profile function for the bulk twist \begin{document}$\tau=6$\end{document} vector field, which describes the deuteron on the boundary and fix the infrared boundary cut-off of AdS space in accordance with the ground state mass of the deuteron. We obtain the deuteron charge monopole, quadrupole, and magnetic dipole form factors and tensor polarization observables from the bulk Lagrangians for the deuteron and photon field interactions. We plot the momentum transfer dependence of the form factors and tensor polarization observables and compare our numerical results with those in the soft-wall model and experimental data.