波荡器对电子储存环束流影响的研究

研究了国家同步辐射实验室二期工程新建波荡器对储存环束流产生的各种影响,计论了在高亮度模式下,波荡器产生的效应。结果表明：波荡器安装在第三直线节在两种工作模式下对环的影响都有小,不影响正常运行,无须补偿。但安装在第四直线节时,在高亮度运行模式下对电子束流的影响较大,如不进行补偿,环将无法正常运行。     

Growth of self-assembled copper nanostructure on conducting polymer by electrodeposition

In the present work, self-assembled nanostructures of copper are grown by electrodeposition on a thin conducting polymer (polypyrrole) film electropolymerized on a gold electrode. The shapes, sizes and the densities of the nanostructures are found to depend on the thickness of the polypyrrole thin film, which provides an easy means to control the morphology of these nanostructures. In particular, for the same applied potential on the gold electrode, smaller nanocrystals with a higher density are observed on thinner polymer films while bigger nanocrystals at a lower density are found on thicker films.     

FPGA状态机在多路异步串口通信处理的实时优势

【】 首先简要介绍了异步串口板的通常设计方法,并且提出了这些方法的不足之处,重点阐述了基于FPGA状态机和片上总线的新设计方案,以及该方案的技术优势,随后公布了基于该方案的异步串口板达到的性能指标。通过比较有关应答延迟的试验数据,提出了基于FPGA状态机和基于DSP处理器的异步串口板卡存在明显的处理速度差异问题,并基于两种设计方案,解释了形成差异的原因。最后提出了FPGA状态机对外部总线存储器或端口的访问管理性能大幅超越了任何一款DSP处理器的观点,并对同行提出了类似研发项目的设计建议。     

Calculations of hyperfine fields

First principle methods for calculation of hyperfine fields in different systems are reviewed. The contributions from energy states close to the Fermi level are emphasized and are responsible for different observed systematic behaviours in the hyperfine field, not directly related to the host magnetic moment. Calculations on Fe, on Fe₂P, on surfaces, on impurity atoms in Fe and on the muon Knight shift in Sb are discussed.     

Generalized Chaplygin equations for nonholonomic systems on time scales

The generalized Chaplygin equations for nonholonomic systems on time scales are proposed and studied. The Hamilton principle for nonholonomic systems on time scales is established, and the corresponding generalized Chaplygin equations are deduced. The reduced Chaplygin equations are also presented. Two special cases of the generalized Chaplygin equations on time scales, where the time scales are equal to the set of real numbers and the integer set, are discussed.Finally, several examples are given to illustrate the application of the results.     

Exact results for deterministic cellular automata with additive rules

Deterministic cellular automata (CA) with additive rules are studied by exploiting the properties of circulant matrices on finite fields. Complete state transition diagrams for higher-order and multidimensional CA on finite lattices are analyzed. Conditions on the rules which make them reversible are obtained. It is shown that all state transition diagrams of the CA have identical trees rooted on cycles. General formulae for cycle lengths and multiplicities are given.     

重离子碰撞中的核温度

介绍了基于不同近似下的核温度的测量方法。不同测量方法给出的核温度不尽相同,这是因为它们使用的基本假设不一样。讨论了原子核系统的特殊性,这些特殊性使得核温度的提取特别困难。重点比较了动力学近似的几种温度计:使用经典Maxwell-Boltzmann 近似的,和使用量子Fermi-Dirac近似的。使用氦锂温度计对照考虑费米子属性后的斜率温度计和涨落温度计,发现考虑费米属性后提取的核温度更接近于热力学温度。仍需更多的工作,从核体系的孤立性、有限性和费米子属性等方面来研究核系统热力学温度的提取方法。Nuclear thermometers based on different approaches are reviewed. Due to the different basic assumptions of these methods, the nuclear temperatures extracted by different thermometer approaches are not consistent. Moreover,several problems which make the extraction of the nuclear temperatures even more difficult are discussed. The nuclear thermometers based on different kinetic approaches are compared. The nuclear temperatures extracted by methodsbased on quantum (Fermi-Dirac) kinetic approaches are compared to the double ratio temperatures THe; Li. Perspectives for future investigations of the thermal temperature are given.     

Effects analysis of ambient conditions on process of laser surface melting

In the process of laser surface melting (LSM), ambient conditions around the workpiece have important influences on the processing results. As an effective and feasible method for ambient changing, water-assisted approach can be expected to gain better results such as desired machining goals and reliable service performances. However, the effects of different water ambient on LSM process are needed to be further clarified. To this end, three 3-D transient process models in ambient dry air, water film and water are developed, respectively, using finite element method (FEM); the thermo-mechanical parameters, which depend on temperature, are taken into account and the complex physical essences are integrated. In experimental verification, these three LSM processes on mild steel Q235 are carried on and the computed results are in good agreement with respective measurements. Based on the proposed models, the transient temperature fields and residual stress distributions on workpieces are investigated. The numerical results suggest that the states of temperature and residual stress fields can be improved to different degrees using water film and water ambient.     

On Current Distribution through the Cross-Section of an Arc Moving in a Narrow Insulating Slot

Current distribution across the arc plasma cross-section constructed in a narrow slot between isolating walls and other factors affecting the distribution are considered. Experimental data on current density distribution of the arc moving at subsonic velocity are analyzed. Data available on the mean current density in an arc moving at supersonic velocity and under phase transition conditions on an active surface of the walls (gas-gen erating) are summarized. Possible influence of conditions of heat transfer with walls and pressure inside the column on the extent of non-uniformity of current distribution on the arc cross-section are shown. The problems under consideration are of practical application for avoiding thermal overload of arc chambers of magnetic-blast breakers.     

Phase transitions in metals on metals

Phase transitions in two-dimensional metal layers on metal surfaces are discussed, with emphasis on systems with attractive lateral interactions on densely packed surfaces. The experimental tools which give information on these transitions are described briefly and the results obtained with them are illustrated by examples of various metals on W and Mo surfaces.     

Long-range effect under low-intensity irradiation of solids

Experimental results of the study of long-range low-intensity irradiation with light effect on the microhardness of silicon plates and aluminum foils (including the irradiation of aluminum/silicon stacks) are presented. These results for silicon agree with the data on irradiation effect on a system of microdefects. Some results on the small-dose long-range effect on the above mentioned materials are also given. The results are discussed using a model of the effect of radiation-induced acoustic waves on defects in solids.     

Roles of electric field on toroidal magnetic confinement

Theoretical research on the influence of electric field on toroidal magnetic confinement is surveyed. The static electric field is first described. A physical picture of the radial electric field generation and its influence on confinement are shown. Neoclassical effects as well as the non-classical processes are discussed. Emphasis is made on the connection with improved confinement. Convective cells with a nonuniform potential on the magnetic surface are also discussed. The roles of the fluctuating electric field are then reviewed. Recent progress in anomalous transport theory is addressed. Through these surveys, the impact of experiments using the heavy ion beam probes on modern plasma physics is illustrated     

基于半导体光放大器交叉增益调制(SOA-XGM)波长变换器仿真研究

本文在PTDS(Photonic Transimission Design Suite)软件仿真平台上对基于半导体光放大器交叉增益调制(SOA-XGM)的波长变换器的变换特性作了仿真实验研究,仿真并分析了输入信号光功率、输入探测光功率、偏置电流和SOA的结构参量等因素对变换信号的消光比(ER)、Q值及误码率(BER)的影响关系.研究结果对优化设计SOA-XGM波长变换器有一定的参考价值.     

External noise and the origin and dynamics of structure in convectively unstable systems

Some basic concepts and earlier work on external noise and the convectively unstable Ginzburg-Landau equation are reviewed, and some of the ideas presented in the earlier work are investigated further and extended. In particular, further consideration is given to convective chaos-chaos which only occurs in a moving frame of reference; and slugs-localized structures which are surrounded by a stable stationary state. Some new results on secondary convective instabilities and on periodic systems with a spatially varying instability are discussed. Work on the coupled Ginzburg-Landau equation is reviewed. Actual physical systems are discussed.     

Formation of “Fuzz” on the Pre-Nitrided Tungsten Surface

Experiments are carried out on a simulation stand with a plasma-beam facility in order to study the formation of “fuzz” on the initial and pre-nitrided tungsten surface. The parameters of the experiments of the nitriding and formation of the tungsten “fuzz” are given. The results of materials science study are shown. The characteristics of the tungsten “fuzz” on the nitrided and non-nitrided tungsten surfaces are determined and the results obtained are analyzed.

     

Breakup reaction models for exotic nuclei

Breakup reactions are one of the main tools for the study of exotic nuclei. In particular, Coulomb breakup is expected to provide information on spectroscopic properties of halo nuclei and on astrophysical S factors for radiative-capture reactions. The simplest studies are based on perturbation theory and especially on its first order. However the validity of the first-order approximation may be limited for extended systems such as halo nuclei and its conditions are not always satisfied in existing experiments. More elaborate reaction models are available: resolution of the semi-classical time-dependent Schr?dinger equation, eikonal and dynamical eikonal approximations, method of coupled discretized-continuum channels, adiabatic approximation. These methods are reviewed, summarized and illustrated. Their interest and limitations are discussed.     

Derivation and low density solution of a nonlinear Kirkwood-Salsburg equation

Nonlinear Kirkwood-Salsburg equations which are parametrized by the density ? are derived from the linear ones by elimination of the activity z. Upper bounds on ? are derived below which the solution of these equations is unique. Narrow upper and lower bounds on z(?) are obtained as well as upper bounds on the pair distribution function. Nonlinear Mayer-Montroll equations are also briefly discussed.     

ANALYSIS OF THE GENERAL EFFECTS IN DOUBLE-GRATING DIFFRACTION-INTERFERENCE SYSTEM

Based on the ambiguity function, the optical phenomena of the double-gearing diffraction-interference system are analysed with partially coherent illumination. Different patterns are observed on the observation plane when the optical elements are placed in their proper positions. Detailed discussions on the two extremes of coherence are given. Conclusions could be obtained about the Lau effect, the generalized Lau effect, the incoherent grating-lens imaging, the Talbot effect, the joint-Talbot effect and the generalized joint-Talbot effect. Some special cases are also verified by experiments.     

Invariance under conformal coordinate and point transformations

Coordinate and point transformations are studied in the context of conformal symmetry. When invariance requirements on arbitrary rank tensors are involved in both contexts, the similitudes and differences in transformation laws and invariance conditions are analysed in connection with those on tensor densities of weight W. Physically interesting tensors like the metric tensor, the electromagnetic field and the energy-momentum tensor are specifically examined. Some remarks on scalar fields and densities are added.     

铁基金属包膜界面的精细结构与金刚石单晶生长

 采用场发射扫描电子显微镜（FESEM）,研究了铁基金属包膜界面及其断面的精细结构。结果表明：包膜（100）界面有纳米级的棱锥状突起,包膜（111）界面上分布着锯齿状的台阶;金属包膜近触媒侧的界面断面表层分布着台阶形貌的胞状突起;断面其它断层断口呈现脆性断裂特征,断层表面分布着团簇状的纳米颗粒。分析认为：包膜界面的不同形貌与片状金刚石结晶基元的不同生长过程有关;由于包膜内脆性碳化物的存在,包膜断面呈现脆性断口特征;断面上分布的纳米级颗粒可能是金属成分的共晶析出产物。