胶子有效质量对重夸克势的影响

本文采用椭球袋模型讨论胶子有效质量对重夸克势的影响.我们分别计算了胶子有效质量0,0.2,0.4,0.6和1.0GeV时的重夸克势.计算结果表明,除汤川势外,势仍近似地呈线性,随着胶子有效质量的增加,斜率逐渐减小.     

非线性超场和夸克禁闭

利用非线性超场技术,我们讨论了超对称的非线性场论模型.找到了超对称运动方程精确静态解的一般形式,它可以作为袋模型的出发点。作为一个特殊情形,我们重新得到了 SLAC 袋模型,也就是说,SLAC 袋是超对称的.文中还讨论了超对称的 Sine-Gordon 模型、Sinh 模型和 exp 模型.     

碘与铯同位素高自旋带结构的区别

理论上指出由于在单粒子能级图上,扁椭球和长椭球的两侧均存在下降轨道,因此Z=52－56原子核会有低位的扁椭球转动带.最近对碘和铯同位素的高自旋带结构进行了仔细的实验研究,发现碘同位素中除有长椭球转动带外,确有质子h_11/2、g_7/2和d_5/2组态的扁椭球转动带.但是在铯同位素中,迄今都只发现长椭球转动带,而未发现扁椭球转动带.利用新调整过的Nilsson参数,进一步作了计算.结果表明,对于扁椭球形状,碘同位素的壳修正能及自洽对关联的绝对值均大于铯同位素的;而且碘同位素与铯同位素比较,带头扁椭球与长椭球能量差,也更有利于扁椭球形变.这一切结果均密切联系于单粒子能级图上存在一个扁椭球质子54能隙的事实.     

NO_2分子激光诱导荧光辐射寿命和碰撞猝灭速率的实验研究

实验测定了激发波长在 591～ 594nm范围 ,压力在 0 .1～ 15Pa时 ,NO2 分子激光诱导荧光衰减曲线 ,作几何修正后应用Stern Volmer模型 ,得到了零压辐射寿命τ0 ( =1/k0 )和碰撞猝灭速率常数kq,结果与文献报道基本一致。对NO2 分子激发态能级的反常长寿命和一定压力下出现的双指数衰减等进行了较详细的讨论。     

强电场下气泡形变对液体绝缘的影响

 基于液体气泡击穿的椭球模型,推导了气泡形变的流体动力学方程;利用软件Comsol模拟了气泡受力后的形变;根据模拟结果,结合气体击穿的帕邢定律,讨论了气泡形变对液体绝缘的影响。结果表明:气泡在静电引力和表面张力的作用下,沿电场线方向拉伸成椭球,椭球长短轴之比与外加电场强度和气泡初始半径成正比;形变导致电场方向气体通道延长,气泡更容易击穿,外加气压是避免气泡击穿的有效途径之一,外加气压的大小与电场强度和气泡初始半径成正比。     

Yb原子|m|=0,1里德伯态能级Stark结构

用两步激发和光电离方法,在0-1500V/cm电场范围内,测定了Yb原子n=17至n=20附近.m=0和|m|=1的Stark光谱.采用数值积分方法对实验研究范围内的Stark能级结构作了计算,理论与实验结果基本符合.讨论了电场中能级的抗交叉行为及其与量子亏损的关系,并对m=0和|m|=1两种Stark能级结构的特点作了比较. 关键词：     

氦同位素原子与钠分子碰撞转动激发积分散射截面的理论计算

多体刚性椭球模型是一种比较精确的描述氦原子与钠分子碰撞的理论模型.本文用多体刚性椭球模型计算了不同能量下He的同位素原子3He,4He,7He,10He与Na2分子碰撞的转动激发积分散射截面,表明增加椭球等势面个数可以得到更准确的转动激发积分散射截面;总结出3He,4He,7He,10He-Na2碰撞体系转动激发积分散射截面随相对入射能量和体系约化质量变化的规律;讨论了相对入射能量为100meV时,相互作用势的不同区域对4He-Na2碰撞体系转动激发积分散射截面的影响情况.     

非拓扑孤子模型的袋常数与退禁闭相变

用有限温度场论方法,通过计算非拓扑孤子袋模型中与温度和密度相关的有效势,进而得到了袋常数随温度和化学势的变化关系,相应地讨论了退禁闭相变的性质.     

雨滴对电磁波的散射特性研究

由于重力和向上气流的作用,高速摄影显示较大的雨滴在降落过程中表现为一底部扁平、顶部圆滑的非球形对称体,已有的模型中BC模型(由Beard和Chuang提出)被认为能准确描述雨滴的形状。本文利用沿降落方向旋转对称的扁椭球体和均匀球体模拟降落中的雨滴,扁椭球体的短轴(旋转轴)与BC模型的相等,长轴通过与BC模型截面积等效法确定;利用T矩阵方法研究了水平取向的旋转扁椭球体和BC雨滴模型的散射特性,利用Mie理论计算了均匀球的散射特性,比较了半径分别为2 mm和3 mm大小的三种雨滴模型对94 GHz电磁波斜入射时的单次散射相矩阵,以及对频率为30 GHz~100 GHz电磁波的单次散射反照率,最后讨论了半径为0.5 mm~3.5 mm雨滴对35 GHz和94 GHz的后向散射函数。计算结果表明,利用均匀球模拟雨滴将带来较大误差,而利用截面积等效的旋转扁椭球体模型可以较好地模拟雨滴的散射特性。     

椭球内反射的几何光学性质

本文讨论椭球的内反射性质。由椭球的一个焦点F_1发射出的光波将在反射过程中与椭球的长轴充分逼近,使焦点F_1所具有的辐射以极狭窄的光束从椭球长轴的一端发射出来。     

SELF-ENERGY IN THE BAG MODEL

Based on the many-body theory of confined quarks and gluons^[l], the ultraviolet divergence of the self energy in the bag model is discussed. It is shown that for massless quark the self energy is finite and it is 1ogarithmically divergent for massive quark. The numerical calculation is performed for m=0 and m=1.0(in unit 1/R). The self energy has important effects on the bag model and changes the parameters in this model considerably. Furtherstudy of selfenergy and mass renormalization is necessary.     

QCD Phase Transitions and Bag Constants at Finite Chemical Potential

The global colour model at finite temperature is further extended to study the systems at finite chemical potential. The deconfinement and chiral phase transition at finite chemical potential and at temperature T = 0 K are studied simultaneously. Meanwhile the evolution of the bag constants at finite chemical potential is calculated. The dependences of results on the model parameters are discussed in detail     

The quark condensate in the bag-like QCD vacuum

The quark condensate in the bag model of the QCD vacuum is discussed. It is shown that the systems with J^PC=0⁺⁺ quantum numbers produce a much deeper minimum in the energy density than the recently suggested glueball condensate. Some consequences of this observation are pointed out.     

Bag model of hadrons with massive quarks

We generalize the bag model of hadrons to include massive quarks and investigate in particular the properties of the l = 0 octet and decimet baryons with m_p = m_n = 0, m_λ = 270 MeV (obtained by fitting the decimet). The magnetic moments and weak axial vector/vector transition moments are calculated and compared with experimental data for cases in which data exists. We also speculate on the mechanism by which the remaining degeneracies in the baryons are lifted and on modifications which are necessary to construct a bag model of mesons.     

LONG RANGE POTENTIAL BETWEEN NUCLEONS

Using hybrid chiral bag model, one gets a model which can be used to calculate potential between two separate nucleons. It is shown that the obtained results, centre and tensor potential, are compatible with phenomenological potentials such as Hamada-Johnston potential and Reid potential. Whether the bag radius for a free nucleon is different from that of a nucleon in the nuclear matter is discussed.     

A BAG MODEL WITH PSEUDOSCALAR MESON CLOUD

Using SU(3)×SU(3) symmetry the bag model with pion cloued suggested in re-cent years is generalized to the bag model containing K, η, η′meson cloud. The massspectra of hadrons are calculated and the origin of pion cloud is discussed.     

THE VIRTUAL EXCHANGE OF PSEUDOSCALAR MESONS IN THE MIT BAG MODEL

In this paper the virtual exchange effect of pseudoscalar mesons in the MZT bag model is discussed and the mass spectrum of hadrons,the magnetic moment's and the mean square values of charge radius are calculated. It is pointed out that our model can pre-serve and improve the static properties of the MIT bag model and provide an explanation for the origin of the meson cloud outside.     

DECAY π0→2γ IN THE MIT BAG MODEL

In this paper the MIT bag model and wave Packet Method are used to calculate the width of the process π⁰→2γ It is found that m_π→0 is a good approximation. The results are consistent with PCAC. The theoretical value of Γ(π⁰→2γ) is 2.7 times of the experimental value. The deviation is mainly from the calculation of F_π. It is also found that the deviation strongly depends on the equation and the boundary contion of the MIT bag model.