Kinetic description of particle emission from expanding source

The freeze out of the expanding systems, created in relativistic heavy ion collisions, is discussed. We combine kinetic freeze out equations with Bjorken type system expansion into a unified model. The important feature of the proposed scenario is that physical freeze out is completely finished in a finite time, which can be varied from 0 (freeze out hypersurface) to ∞. The dependence of the post freeze out distribution function on the freeze out time will be studied. As an example, model is completely solved and analyzed for the gas of pions. We shall see that the basic freeze out features, pointed out in the earlier works, are not smeared out by the expansion of the system. The entropy evolution in such a scenario is also studied.     

MICROMEGAS一维位置编码读出初步测试

介绍了微型网状结构的气体探测器一维位置编码读出的基本原理和实现方法。设计了一块灵敏面积为10 cm×10 cm的一维位置编码PCB读出电极。测试表明: 感应读出是可行的, 电荷按1∶2分配最为理想; 利用55Fe放射源X射线通过200 μm狭缝对准读出电极PCB板的正面中任意一条, 位置编码读出能很好地再现源所在狭缝的位置。针对其局限性, 提出了一维位置分组编码读出技术, 以解决相邻多条同时点火的情况。使用该读出技术, 使一维读出电子学路数节省量达到75%以上。The basic principles and implementation of one dimensional position encoding read out for MICROMEGAS have been introduced in this paper. A 10 cm×10 cm prototype of one dimensional position encoding read out electrode based on printed circuit board was designed. Preliminary test indicates that the induction read out is feasible and the ideal charge distribution is 1∶2. X rays emitted from 55Fe source were collimated to one of strips on the read out electrode through a slit of 200 μm, position decoding well reproduced the position of the 55Fe source. For its limitations, we have proposed a one dimensional grouped position encoding read out technique to address a neighboring strips simultaneously fired situation. The amount of read out electronics is very easy to approach a obduction of 75% with position encoding read out technology.     

光格子中玻色-爱因斯坦凝聚体的超流相

本文采用Bogliubov方法分析了光格子中玻色-爱因斯坦凝聚体的能谱,得到超流-Mott相变条件,指出光格子中BEC是一种典型的超流态,最后给出了超流速度.     

Interaction between a Sphere and a Gaussian Beam: Computations on a micro-computer

This paper presents some characteristics of the light scattered by one spherical particle illuminated by a Gaussian beam. The basic theory is a generalization of the Lorenz-Mie Theory. The fact that the computations can be easily carried out on a micro-computer is pointed out.     

Measurement of the dipole and electric quadrupole strength distributions up to 10 MeV in the doubly magic nuclei 40Ca and 48Ca

We have made the first detailed measurements of a diffusive supersonic radiation wave in the laboratory. A 10 mg/cm(3) SiO2 foam is radiatively heated by the x-ray flux from a laser-irradiated hohlraum. The resulting radiation wave propagates axially through the optically thick foam and is measured via time-resolved x-ray imaging as it breaks out the far end. The data show that the radiation wave breaks out at the center prior to breaking out at the edges, indicating a significant curvature in the radiation front. This curvature is primarily due to energy loss into the walls surrounding the foam.     

离焦模糊图像的维纳滤波恢复

为消除离焦误差产生的图像模糊,介绍了基于逆滤波和维纳滤波的离焦模糊图像复原方法。从光学成像原理出发,根据高斯方程计算离焦误差,建立离焦误差与光学传递函数之间的关系。讨论了离焦误差对光学成像系统传递函数的影响。通过建立线性空间不变的模糊模型,构建点扩散函数和光学传递函数,采用与模糊过程相反的处理方法进行图像复原,消除离焦误差造成的图像模糊。测试实验中,对标准样本Lena图像进行了离焦模糊处理,采用维纳滤波算法复原图像,选择不同的离焦半径和维纳滤波参数进行对比。实验结果表明:维纳滤波方法可有效消除离焦模糊;抑制噪声干扰和"振铃效应";可把图像峰值信噪比提高到6dB以上。     

密封舱室内氧气再生过程的模拟计算

建立了封闭舱室内氧气再生与二氧化碳降浓的数学模型,采用S-系统在对数空间内对模型进行了数值解析,通过计算机模拟计算,讨论了系统中氧气和二氧化碳浓度随时间的变化情况,以及小球藻的液相培植对气相中氧气浓度的影响。计算结果表明通过培植小球藻来再生氧气并减少二氧化碳,维持密封舱内生命生存是可能的。     

An investigation of merging and diverging cars on a multi-lane road using a cellular automation model

In this paper,we have investigated two observed situations in a multi-lane road.The first one concerns a fast merging vehicle.The second situation is related to the case of a fast vehicle leaving the fastest lane back into the slowest lane and targeting a specific way out.We are interested in the relaxation time τ,i.e.,which is the time that the merging(diverging) vehicle spends before reaching the desired lane.Using analytical treatment and numerical simulations for the NaSch model,we have found two states,namely,the free state in which the merging(diverging) vehicle reaches the desired lane,and the trapped state in which τ diverges.We have established phase diagrams for several values of the braking probability.In the second situation,we have shown that diverging from the fast lane targeting a specific way out is not a simple task.Even if the diverging vehicle is in the free phase,two different states can be distinguished.One is the critical state,in which the diverging car can probably reach the desired way out.The other is the safe state,in which the diverging car can surely reach the desired way out.In order to be in the safe state,we have found that the driver of the diverging car must know the critical distance(below which the way out will be out of his reach) in each lane.Furthermore,this critical distance depends on the density of cars,and it follows an exponential law.     

被动式渔探仪开发设计与试验研究

本论文就被动式渔探仪的开发设计做了理论上的探讨，并就总体技术方案做了试验研究，同时对于设计思想、技术路线及分析方法也做了多方面的尝试。论文的主要内容包括：被动式渔探仪的目标检测与方位估计，目标特征提取与分类识别。系统进行了湖上实验，得到了包括目标检测、方位估计和分类识别的部分实验结果。     

Irreducibility and Compositeness in q-Deformed Harmonic Oscillator Algebras

A study of the reducibility of the Fock space representation of the q-deformed harmonic oscillator algebra for real and root of unity values of the deformation parameter is carried out by using the properties of the Gauss polynomials. When the deformation parameter is a root of unity, an interesting result comes out in the form of a reducibility scheme for the space representation which is based on the classification of the primitive or nonprimitive character of the deformation parameter. An application is carried out for a q-deformed harmonic oscillator Hamiltonian, to which the reducibility scheme is explicitly applied.On leave from     

变参数波振器小信号增益的三维效应

本文对前文导出的变参数波振器小信号增益积分表达式,利用非均匀天线阵列概念与Madey定理作出了物理解释,并将该式推广为三维。我们考虑了电子束发射度,不同聚焦方式,光束的强度与相位横向分布以及FEL系统中磁场轴、电子束中心、光轴三轴不准直……对增益的影响,进行了数值计算。作为具体实例,我们对波音公司的实验装置进行了数值计算,与他们的数值摸拟结果作了比较。     

Shell corrections for highly asymmetric systems

It is pointed out that a routine application of existing codes to the calculation of Strutinsky-type shell corrections may lead to erroneous results for systems with high mass asymmetries. The reasons for these errors are pointed out and a modification of the shell correction method is proposed that avoids these difficulties.     

Nonequilibrium zero-bias anomaly in disordered metals

We extend the theory of a zero-bias anomaly (ZBA) in the tunneling density of states of a diffusive metallic film to out-of-equilibrium conditions. An effective action describing virtual fluctuations out of equilibrium is derived. The singular behavior of the equilibrium ZBA is smoothed out by real processes of inelastic scattering.     

连续面型高效率光栅分束器件的设计

阐述了用虚源法设计连续面型光栅分束器件的原理 ,提出了一种局部搜索遗传算法 ,并将其用于优化器件的性能。局部搜索遗传算法结合了局部搜索算法和遗传算法的优点 ,可以有效地克服遗传算法的“早熟收敛”现象 ,具有更强的全局收敛能力。用文中给出的方法可以得到具有较好均匀性的、高衍射效率的连续面型光栅分束器件。     

Senile scaling in electron-positron annihilation

An important difference is pointed out between the approach to scaling behaviour in deep inelastic scattering and annihilation. In the framework of the massive quark model a quantitative analysis of the breaking terms is carried out for the total and the one-particle inclusive cross-sections. Good agreement with available data is found.     

Selektion eines Pikosekundenimpulses aus einem lmpulszug mit Hilfe von sättigbaren Absorbern und Absorption in angeregten Zuständen

Selection of a Picosecond Pulse out of a Pulse Train by Saturable Absorbers and Absorption in Excited Levels The absorption of pulses out of a pulse train under the combined action of a saturable one-photon-absorber (in the ground level) and an one-photon-absorber (after two-photon-absorption) in an excited level is calculated. For several absorber arrangements the system of rate equations is solved and their suitability for pulse selection is studied.     

Gauge Covariance and Momentum Space Asymptotically Non-logarithmic Total Derivatives

We focus on a new gauge symmetry keeping regularization scheme for momentum integration and point out that dropping out momentum space asymptotic non-logarithmic total derivative divergent integrations in quantum field theory is a simple and natural way to keep the computation program gauge-covariant.     

Averaging out the Einstein equations

A general scheme to average out an arbitrary 4-dimensional Riemannian space and to construct the geometry of the averaged space is proposed. It is shown that the averaged manifold has a metric and two equi-affine symmetric connections. The geometry of the space is characterized by the tensors of Riemannian and non-Riemannian curvatures, an affine deformation tensor being the result of non-metricity of one of the connections. To average out the differential Bianchi identities, correlation 2-form, 3-form and 4-form are introduced and the differential relations on these correlations tensors are derived, the relations being integrable on an arbitrary averaged manifold. Upon assuming a splitting rule for the average of the product including a covariantly constant tensor, an averaging out of the Einstein equations has been carried out which brings additional terms with the correlation tensors into them. As shown by averaging out the contracted Bianchi identities, the equations of motion for the averaged energy-momentum tensor do also include the geometric correction terms. Considering the gravitational induction tensor to be the Riemannian curvature tensor (then the non-Riemannian one is the macroscopic gravitational field), a theorem that relates the algebraic structure of the averaged microscopic metric with that of the induction tensor is proved. Due to the theorem the same field operator as in the Einstein equations is manifestly extracted from the averaged ones. Physical interpretation and application of the relations and equations obtained to treat macroscopic gravity are discussed.     

Lorentz deformation and the jet phenomenon. II. Explanation of the nearly constant average jet transverse momentum

It is shown that the jet mechanism derivable from the Lorentz deformation picture leads to a nearly constant average jet transverse momentum. It is pointed out that this is consistent with the high-energy experimental data. It is pointed out further that this result strengthens the physical basis for the minimal time-energy uncertainty combined covariantly with Heisenberg's space-momentum uncertainty relation.