ON THE BEHAVIOR OF PHASE TRANSITION SHOWN IN DISASSYMBLY PROCESSES OF VERY HOT AND DILUTE FINITE NUCLEAR SYSTEMS

The behaviors of phase transition shown in disassymbly processes of very hot and dilute finite nuclear system have been exposed by using canonical (microcanonical) ensemble Monte Carlo simulation.It is explained that they result from the competition between Coulomb interaction and the effect of finiteness.     

INVESTIGATION OF THE NUCLEAR SHADOWING EFFECT IN THE SMALL x REGION

In this paper,we analyse the spatial overlapping behavior of sea quarks of neighboring nucleons in nuclei in the small x region and give a relation between the nuclear shadowing factor R(x,Q²,A) and the spatial overlapping factor ΔV_A(x)/V_A(x).By using this nuclear shadowing factor R(x,Q²,A),we calculate the ratios of the average nuclear structure functions of nuclei ¹²C、⁶³Cu and ¹¹⁶Sn,to the deuteron structure function and obtais a better agreement between the calculated result and the experimental data.     

INVESTIGATION OF THE EFFECT OF NUCLEAR SHORT RANGE CORRELATION IN HEAVY ION SCATTERING

Bassed on the "Rigid Projectile" approximation and the Glauber's multiple scattering theory. The influence of the nuclear short range correlation on elastic scattering of high energy heavy ion is discussed. The elastic α-¹²C scattering at 1.37 GeV is calculated and compared with experimential data. It is show that the influence of the unclear short range correlation on differential cross section is quite important.     

微量样品制样时不灼烧,不称重量,不固定体积对XRF分析结果的影响

XRF法分析毫克量级的微量试样,采用不灼烧、不称重量、不固定体积的制样方法,并与灼烧、称重量、固定体积的制样方法比较,分析结果非常接近。文中还讨论了此法用于实际样品分析应注意的几个问题。     

小变形原子核中的相干效应

本文考察了在转动的小变形核力场中运动的核子-核子对、核子-空穴对中的相干效应。计算了O¹⁸最低的偶宇称态0⁺,2⁺,4⁺和O¹⁶最低的奇宇称态0^-,1^-,2^-,3^-波函数;和壳模型经典方法计算出的结果作了比较,二者相当一致。得出的初步结论如下:核力主要是P₂力再加上一定成分具有相干性质的力。前者与转动的变形场等效。不但对于0⁺,2⁺,4⁺,3^-态,而且对于1^-,2^-态,附加的相干成分都很重要;它们的内部态混合组态是比较多的,粒子-粒子之间、或粒子-空穴之间的关联都比较显著。只有0^-态的内部态是纯组态。     

热电子、双离子成分对离子漂移迴旋不稳定性的影响

分析了热电子、温(热)离子成分对离子漂移迴旋不稳定性的影响。给出了临界稳定热电子成分值α与温(热)离子成分值、离子温度比和离子抗磁漂移速度的关系;讨论了热电子、温(热),冷离子成分对不稳定性各谐频分支的影响;分析了热电子成分稳定作用的物理机制。     

THE RELATIVISTIC NUCLEAR MODEL AND EMC EFFECT

A correct relativistic nuclear model is presented on the ratios of structure functions F^A(x,Q²) measured in DIS with several different nuclei.We shall assume here that a nucleus consists of nucleons,antinucleons and excess pions,the pions being associate with the meson exchange forces responsible for nuclear binding,only the baryon number is conserved.It is also considered that shadowing-antishadowing and Fermi motion.Our results are consistent with the available recent data.     

THE INTERFERENCE EFFECTS BETWEEN ATOMIC AND NUCLEAR PROCESSES-FLUCTUATION PHENOMENA IN POSITRON SPECTRUM PRODUCED BY VERY HEAVY ION COLLISIONS

The positron spectra produced by very heavy ion collisions have been measured in GSI. The fluctuation phenomena occured in the positron spectra should be explained in terms of the theory on the interference effects between atomic and nuclear processes, i.e. the origin of this kind of fluctuation essentially comes from the stochastic property of compound ,nucleus.This paper shows the theoretical framework.     

热端温度对高频微型同轴脉冲管制冷机性能的影响及其在空间技术中的应用研究

本文用数值方法对热端温度对微型高频同轴脉冲管制冷机性能的影响进行了分析,并将其与实验结果进行了比较,随着热端温度的升高,制冷机的最低制冷温度单调升高,制冷量单调减少,试验结果与数值计算结果定性相符。在此基础上,探讨了高频微型同轴脉冲管制冷机和辐射制冷器相结合在空间飞行器中的应用,提出了两种应用模式,用数值方法对之进行了分析。     

热稠密等离子体的轫致辐射Gaunt因子分波计算

基于相对论自洽场离子球模型,态密度采用完全的相对论计算,给出连续态波函数.Gaunt因子采用分波形式计算,并将结果与Born-Elwert近似结果比较.     

原子核裂变的发现：历史与教训——纪念原子核裂变现象发现60周年

回顾了原子核裂变发现走过的一段弯路，讨论了这段历史提供的启发和教训．     

原子核的同位旋对碎裂产物的影响

用同位旋相关的晶格气体模型系统地研究了Z=54的同位素和A=129的同质异位素热发射体的粒子发射的特性,阐述了发射体系的同位旋对中子、质子和带电粒子产额,以及轻粒子的同位素比及同位素对的比的影响.同时,还比较了在同位旋相关作用势下和同位旋不相关作用势下碎片产物特性的差异.发现了不同质量区间(轻粒子、中等质量碎片和重余核)的产物的平均中子质子比,在同位旋相关的或不相关的作用下它们有十分不同的温度依赖性.发现核气态(轻粒子)的要大于核液态(重余核)的,也就是说在液气共存时的气态有 关键词：     

DIFFUSENESS AND DEFORMATION EFFECT IN NUCLEAR CHARGE RADIUS

On the basis of Yukawa folded density distribution, a new formula of nuclear charge radius is proposed to include the effect of both spheroidal and tetroidal deformation. With the values of only two constants, the resulting root-mean-square error in calculated nuclear radii of 148 nuclides is 0.034 fm, which is near to that of Droplet model. It can be used to explain the nuclear radii of some isotopic sequences where the Z^1/3 law has difficulties. Taking the fluctuation of diffuseness width into account, the peculiar behaviors of some isotopic sequences can be well explained. The dependence of all the fluctuation on the neutron shell structure is also discussed.     

掺杂和共生对层状钙钛矿铁电材料剩余极化的影响

掺杂与组构共生结构都是增大铋系层状钙钛矿结构铁电材料（BLSFs）剩余极化（2Pr）的有效手段。同价元素掺杂时，2Pr的变化由氧空位浓度，晶格畸变程度，铋氧层的完整性，以及掺杂离子与氧离子的形成的共价键强弱有关。高价阳离子对A、B位进行掺杂时，都可降低氧空位浓度并减弱其动性，从而增大2Pr。两种不同的BLSFs组构成共生结构后，铋氧层以及与之相连的氧八面体的结构都发生变化，使共生结构的2Pr大于其任一组成单元。2Pr的增大还可通过改进制备工艺来实现，如进行高温（高于居里温度）淬火等。     

EFFECT OF NUCLEAR VISCOSITY ON FISSION PROCESS

According to the fission diffusion model,the deformation motion of fission nucleues is regarded as a diffusion process of quasi-Brownian particles under fission potential,Through simulating such Brownian motion in two dimensional phase space by Monte-Carlo method,the effect of nuclear viscosity on Brownian particle diffusion is studied,Dynamical quantities,suchas fission rate,kinetic energy distribution on scission,and so on are numerally calculated for various viscosity coefficients,The results are reasonable in physics,This method can be easily extended to deal with multi-dimensional diffusion problems.     

THE WIDTH FLUCTUATION CORRECTION IN STATISTICAL THEORY OF NUCLEAR REACTIONS

In the width fluctuation correction calculation of compound nuclear reaction,we have made a unified treatment of the reaction processes of particle emission,gamma emission and fission processes,in which the residual nuclei can be in discrete states or in the continuum.The calculated results of inelastic cross sections and the cross sec-tions for particle emission,gamma emission and fission processes are self-consistent.     

生物物理学的几个热点领域

物理学与生物科学的交叉由来已久，这不仅解决了自然界许多重大的理论问题，并且在高层次上开辟了新的技术领域，如生物信息学、纳米生物学和脑与认知科学等，文章对当今生物物理学的这几个热点领域进行了介绍。     

路径对摩擦力做功的影响

本文通过讨论两种临界情况下摩擦力所做的功的变化情况，进一步阐明非保守力做的功与路径有关．     

空间差分格式对有限体积法数值散射的影响

数值散射是辐射传递方程近似算法中最常见的离散误差。本文主要讨论空间差分格式对有限体积法数值散射的影响。构造激光平行及倾斜入射的物理模型,验证和比较阶梯格式、中心差分格式及指数格式下温度场的计算精度及数值散射特性。计算结果表明,在激光平行入射与倾斜入射两种情况下,阶梯格式引起的的数值散射比菱形格式及指数格式要多,但其计算精度高于菱形及指数格式。不同激光入射条件下,各种差分格式表现出的数值散射分布有明显的差异。     

约束条件对注装TNT中拐角效应的影响

 利用电探针技术测量了注装TNT中主发药柱约束条件不同时，爆轰波绕射过程中在不同方向上传播的相对延迟时间。结果表明，缩短相对延迟时间可以通过以下两种方法：（1）利用约束材料提高主发药柱中爆轰波强度；（2）利用约束材料中冲击波的起爆能力。