重整化群变换应用于U(1)规范理论的定量分析

在Migdal及Migdal-Kadanoff重整化群变换方案中,我们导出了U(1)格点规范理论的强耦合(高温)近似和弱耦合(低温)近似,同时还得到了包括中间耦合区的数值结果。上述结果与严格的强耦合展开、弱耦合展开以及Monte-Carlo模拟结果进行了比较。 关键词：     

THERMODYNAMIC ANALYSIS AND FORMATION ENTHALPY CALCULATION OF OXYGEN VACANCY DEFECT IN DOPED LITHIUM NIOBATE CRYSTALS

Based on the thermodynamic analysis of oxygen vacancy defects in lithium niobate (LiNbO₃ (LN)) and the data of thermogravimetric experiment, the formation enthalpies of congruent and several rare-earth (RE) doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping with valence-changeable RE ions. The experimental results were discussed and a new reduction process for photorefractive LN crystals at a relatively low temperature was proposed, and the reduction-treated crystals showed good effect in practical use.     

α-AlPO4晶体弹性温度特性的研究

研究了用缓慢升温法生长的α-AlPO₄晶体的弹性温度特性。测量采用传输法,测温范围为-30—150℃;用最小二乘法拟合弹性-温度曲线;用电子计算机处理数据。给出了弹性常数c_ij和s_ij(i,j=1,2,…,6)的温度特性方程以及T₀=25℃时的一级、二级和三级温度系数。 关键词：     

HL-1装置等离子体特性的初步研究

HL-1装置在环向磁场2.3T下运行,获得135kA平衡稳定等离子体,平顶时间160ms。实验表明,环向磁场杂散分量约为纵场的万分之一,导体壳和平衡场基本上能保证等离子体的平衡。观察到的电子温度约500eV,平均电子密度2.8×10~(13)cm~(-3),能量约束时间10ms,有效电荷数小于3,最低稳定运行安全因子2.5,最长放电持续时间1040ms。在对MHD稳定性进行观察的基础上,确定了稳定运行区域;极限密度服从Murakami定标律。     

SYMMETRY PROPERTIES OF NEMATIC LIQUID CRYSTALS WITH SIMPLE CURVATURE STRAIN

In this paper we show analyticaliy that,in general,nematic liquid crystals (NLC) with curvature strain belong to the C₁[1] point group.However,NLC with simple splay deformation or simple bend deformation possess C_2V[mm2] symmetry and those with simple twist deformation possess D₂[222] symnetry.     

以改进的定域密度近似研究核子-有限核的相对论微观光学势

本文以Walecka模型为基础,研究改进的定域密度近似下的核子-有限核的相对论微观光学势。采用高斯形状因子折叠定域密度近似下的光学势,得到包含相互作用力程效应的改进的定域密度近似下的光学势。高斯形状因子中的参数由符合P-⁴⁰Ca光学势的体积分与均方根半径的唯象值来决定。与定域密度近似计算相比,改进的定域密度近似下的微观光学势与唯象势更加接近,以此光学势分析质子与核的弹性散射,亦得到与实验值符合得更好的结果。 关键词：     

sine-Gordon模型与高斯波泛函方法

应用高斯波泛函方法,研究了sine-Gordon模型的基态、单粒子态和两粒子态。在Cole-man临界点附近,sine-Gordon系统趋于零质量玻色子系统,从而具有共形对称性。本文同时证明,当重整化质量有限时,在两粒子态中存在束缚态。 关键词：     

STUDY ON PREPARATION OF UV CROSS-LINKING FILMS OF POLYURETHANE-LiClO4 COMPLEXES AND THEIR IONIC CONDUCTIVITY

The complexes of polyurethane containing double bonds with LiClO₄ were formed, and cross-linked films were produced by UV radiation, All of the films were uniform, transparent, flexible and smooth-faced with a considerable mechanical strength. The ionic conductivities of the films of several series of polymers with different molecule weights of PEG segment were measured, of which the highest is 8.09×10^-5S·cm^-1 at 300K under anhydrous atmosphere. Also the conductivity is deeply influenced by the molecule weight of the soft segment PEG of the polyurethane and the content of LiClO₄. The transport number of Li⁺ is about 0.57. Structure characteristic measurement much as DSC, XRD, IR etc., have been done and the conductive mechanism is discussed.     

顺磁物质CeF3磁光Faraday效应及其温度特性的量子理论

本文计算了顺磁物质CeF₃因Ce³⁺离子从基态能级4f至5d的电偶极跃迁产生的Fara-day旋转。讨论晶场对Ce⁺³离子4f和5d能级的影响,通过唯象地引入一个与磁化强度M成正比的“附加磁场”H_m=λM,由此获得4f离子在外加磁场和“附加磁场”的共同作用下的一级Zeeman分裂。经劈裂后的两个子能级上各自产生左、右圆偏振光激发的电偶极跃迁,导致磁光Faraday效应。对于波长为0.6328μm的入射光,在60—300 关键词：     

共振光的大折射率

揭示了在多能级原子介质中的一种新现象:利用原子相干可使共振光获得明显大于1的折射率.