杂质引起的非费密液体行为

研究含杂质散射的电子系统的非费密液体行为.采用单杂质模型,通过格林函数的计算,证明无论有无束缚态,n(=3,2,1)维电子系统都可出现非费密液体行为. 关键词： 杂质 非费密液体行为     

δ掺杂的赝形高电子迁移率晶体管AlGaAs／InGaAs／GaAs结构中的费密…

报道δ掺杂赝形高电子迁移率晶体管结构Ａｌ０．３０Ｇａ０．７０Ａｓ／Ｉｎ０．１５Ｇａ０．８５Ａｓ／ＧａＡｓ的光致发光光谱研究的实验结果，除了观察到ｎ＝１电子子带到ｍ＝１重空穴子带，ｎ＝２电子子带到ｎ＝１重空穴子带间的强发光峰，还观察到了ｎ＝１电子子带到ｎ＝１轻空穴子带的弱发光峰，通过变化掺杂浓度来改变费密能级的位置，在这种δ掺杂的ＨＥＭＴｓ的系统中观察了费密边奇异性，并把它归结为费密海与费密边附近未     

二维费密液体理论(Ⅰ)

通过关于二维低密度费密系统准粒子寿命和二维巡游电子系的自旋涨落的计算,本文证明朗道费密液体理论适用于二维相互作用费密粒子系。 关键词：     

无穷排斥作用一维费密气体的热力学

采用巨正则系综理论,对以推斥两体δ函数势作用着的一维非理想费密气体,在极端强耦合情况下的热力学性质进行了讨论,并得出这种模型存在“剩余”熵;最后把结果推广到任意自旋情形。 关键词：     

Union Jack晶格上伊辛模型的自由费密近似解

运用自由费密近似对Union Jack晶格上具有各向异性二体耦合作用及三体相互作用的伊辛模型进行了求解,得到了模型的自由能、自发磁矩和临界点方程。在耦合常数简化为正方晶格上的伊辛模型时,得到了与Onsager一致的解。     

Zn／GaAs（110）系统的表面驰豫及其对费密能级钉扎的影响

在紧束缚近似下，利用自洽总能计算给出了Ｚｎ／ＧａＡｓ（１１０）系统的表面几何结构。证明了低覆盖下Ｚｎ／ＧａＡｓ（１１０）表面驰豫是一普遍现象，它对准确地描述费密能级钉扎位置十分重要。进一步给出了与其它元素吸附和清洁ＧａＡｓｄ（１１０）表面的理论与实验结果之比较。     

费密共振和甲烷的振动能谱

用局域模模型来解释甲烷的伸展和弯曲振动能谱，其中伸展振动和弯曲振动间的相互作用用费密共振项来描写，它由一个伸展振子的玻色产生（或湮没）算子和两个弯曲振子的玻色湮没（或产生）算子乘积的T_d不变组合构成．这模型包含10个参数，与已发表的甲烷振动能谱的实验数据比较，得到能量的方均根偏差为12.38cm^－1． 关键词：     

二维费密液体理论(Ⅲ)——输运性质和声传播特性

本文研究了二维费密液体的输运性质和声传播特性,得到了扩散系数、粘滞系数和热导率的微观表达式以及零声和第一声的有关结果。通过对碰撞积分的讨论,认为须用一系列弛豫时间参数来描述二维液体,这与在三维情形可用一个唯象参数来描述不同。 关键词：     

δ掺杂的赝形高电子迁移率晶体管AIGaAs/InGaAs/GaAs结构中的费密边奇异性研究

报道了δ掺杂赝形高电子迁移率晶体管结构Al_(0.30)Ga_(0.70)As/In_(0.15)Ga_(0.85)As/GaAs的光致发光光谱研究的实验结果,除了观察到n=1电子子带到n=1重空穴子带,n=2电子子带到n=1重空穴子带间的强发光峰,还观察到了n=1电子子带到n=1轻空穴子带的弱发光峰,通过变化掺杂浓度来改变费密能级的位置,在这种δ掺杂的HEMTs系统中观察到了费密边奇异性,并把它归结为费密海与费密边附近未占据的第二电子子带之间的近共振散射作用所致。     

一个可能的P波型重费密子超导体——UBe_(13)

在朗道的费密液体理论框架下,我们解释了重费密子超导体UBe_(13)的超导临界温度随压力变化的实验结果。所得结论是:PBe_(13)可能是一个P波型的重费密子超导体。同时也发现由于加压使得系统的f能级与费密能级的相对移动和f电子与导带电子杂化的增加对S波超导有利,而对P波超导不利。     

Study of critical properties of the frustrated antiferromagnetic Heisenberg model on a triangular lattice

The replica Monte Carlo method has been applied to study critical properties of the three-dimensional frustrated antiferromagnetic Heisenberg model on a layered triangular lattice. Magnetic and chiral critical exponents for this model have been calculated within the finite-size scaling theory. The data for this model have been analyzed for the first time taking into account corrections to scaling. It has been shown that the critical behavior of the frustrated antiferromagnetic Heisenberg model on the triangular lattice differs from the critical behavior of the pure Heisenberg model and is independent of the type of interlayer exchange interaction.     

Lattice dynamics of hcp metals

A lattice dynamical model for hcp metals has been developed which considers ion-ion interaction as a five-neighbour central pair potential and electron-ion interaction in a modified form of Bhatia's model. Complete account of the equilibrium of the hcp lattice including the effect of electron pressure has been considered and as a consequence two equilibrium conditions, necessary for the hcp structure, have been obtained and used in the study. Phonon dispersion curves for four hcp metals, Be, Mg, Y and Ho have been computed for two symmetry directions and a good agreement has been obtained with the neutron data. The results have also been compared with the use of the same model but with a single condition, reported earlier and show in general a significant improvement.     

描述氨水体系VLE行为适宜热力学模型的研究

基于对氨／水体系气液平衡研究的文献调查,选择了Ｇｕｉｌｌｅｖｉｃ等提出的一套等温数据为工作基础,本文研究了状态方程法与活度系数法对氨／水体系气液平衡性质预测的适用性．其中状态方程法分别选用理想体系的计算方法、ＢＷＲ方程、ＳＲ－Ｐｏｌａｒ方程、ＬＫ－Ｐ方程和ＲＫＳ方程;活度系数法是基于气相选用ＲＫＳ方程,液相分别选用ＮＲＴＬ模型、电解质ＮＲＴＬ模型、ＵＮＩＱＵＡＣ模型、ＵＮＩＦＡＣ模型和Ｗｉｌｓｏｎ方程。本研究发现,活度系数法并没有良好表现,而 ＬＫ－Ｐ方程和 ＲＫＳ方程对氨／水体系气液平衡性质预测的适用性显然优于其它方法。     

Phase transitions in the antiferromagnetic Heisenberg model on a layered triangular lattice with the next-nearest neighbor interactions

Phase transitions in the three-dimensional antiferromagnetic Heisenberg model on a layered triangular lattice with the next-nearest neighbor interactions have been studied by the histogram Monte Carlo method. Phase transitions in this model have been studied in the range of the next-nearest neighbor interactions from 0.0 to 1.0. The first-order phase transition has been revealed in the considered interval in the studied model.     

Cyclic period-3 window in antiferromagnetic potts and Ising models on recursive lattices

The magnetic properties of the antiferromagnetic Potts model with two-site interaction and the antiferromagnetic Ising model with three-site interaction on recursive lattices have been studied. A cyclic period-3 window has been revealed by the recurrence relation method in the antiferromagnetic Q-state Potts model on the Bethe lattice (at Q < 2) and in the antiferromagnetic Ising model with three-site interaction on the Husimi cactus. The Lyapunov exponents have been calculated, modulated phases and a chaotic regime in the cyclic period-3 window have been found for one-dimensional rational mappings determined the properties of these systems.     

Observational manifestations of black holes in the Horndeski gravity model

The geodesic equations for black hole solutions in the scalar–tensor Horndeski gravity model with non-minimal kinetic coupling have been investigated. The ranges of model parameters admitting the existence of bounded orbits have been determined. Constraints on the model parameters providing agreement of the model with the observational data on the accretion and motion of bodies in the Solar system have been obtained.     

CALCULATION OF DEMAGNETIZATION CURVES OF NANOCOMPOSITE Pr2Fe14B/α－Fe MAGNETS USING A ONE-DIMENSIONAL MODEL

The demagnetization curves of nanocomposite magnets have been calculated using a one-dimensional model. The results are in agreement with experimental results. The shoulders of the demagnetization curve have also been explained based on the model.     

Mechanical properties of semicrystalline polymer-polypropylene

The elastic properties of polypropylene have been investigated in terms of a phenomenological model, which is a modified form of the Takayanagi’s two-phase model. In the present model both the change of crystallinity and orientation of the crystalline chains have been taken into account. The orientation effect at the drawn state has been considered in a simplified manner. It has been shown that a partially aligned crystalline phase may be considered as a superposition of a perfectly aligned crystalline region in an elastically isotropic randomly oriented crystalline phase. The predicted values of elastic modulus agree with experimental values.     

FRW Cosmology with Variable G and Λ

We have considered a cosmological model of the FRW universe with variable G and Λ. The solutions have been obtained for flat model with particular form of cosmological constant. The cosmological parameters have also been obtained for dust, radiation and stiff matter. The statefinder parameters are analyzed and have shown that these depends only on w and ε. Further the lookback time, proper distance, luminosity distance and angular diameter distance have also been calculated for our model.