Collective Excitations in Spin-2 Bose-Einstein Condensates

The Green＇s functions and the correlation functions in spin-2 Bose-Einstein condensates at finite temperature are defined and the generalized Dyson-Beliaev equations are introduced. We discuss the spin conservation in z direction and decouple the Green＇s functions and the generalized Dyson-Beliaev equations according to different spin conservations in z direction. The anomalous vertex functions are introduced and the self-energies are separated into the proper self-energies and the improper self-energies. The generalized Dyson-Beliaev equations are decoupled according to separation of the self-energies. We calculate the Green＇s functions step by step in the Bogoliubov approximation and discuss the collective excitations in spin-2 Bose-Einstein condensates in the polar, ferromagnetic, and cyclic cases, respectively.     

依赖性药物滥用者头发中微量元素测定及相关分析

为了探讨依赖性药物滥用者头发中微量元素营养水平的变化情况及微量元素与滥用依赖性药物间的相关性,用ICP-AES法测定了195例戒毒所收容的强制戒毒人员和200例健康对照者头发中Al,Ba,Ca,Co,Cr,Cu,Fe,Mg,Mn,Ni,Pb,Sr,Zn等13种微量元素的含量;用SPSS统计软件进行相关分析。结果表明,依赖性药物滥用者头发中锌、钙含量明显低于对照组,铅、铁和镁则明显高于对照组(p＜0.001)。用皮尔逊相关分析分析了依赖性药物滥用者头发中微量元素的相关性,为改善依赖性药物滥用者戒毒期间的免疫功能和巩固戒毒效果提供了依据。     

Taylor expansion method for nonlinear evolution equations

Introduction Thestudyofnonlinearevolutionequationsisafascinatingproblemwhichisattheveryheart oftheunderstandingofmanyimportantproblemsinthenaturalsciences[1,2].Thenonlinear evolutionequationsandtheirnumericalapproximationareveryimportantintheareasof theoreticalmathematicsandcomputationalmathematics.Aninterestingfeatureofthe approximationtheoryofthenonlinearevolutionequationsistheapplicationsofthefunctional analyticmethodstothenumericalapproximationofthenonlinearevolutionequations. Thispaperist…     

LONG TIME BEHAVIOR FOR SOLUTION OF INITIAL BOUNDARY VALUE PROBLEM OF ONE CLASS OF SYSTEMS WITH MULTIDIMENSIONAL INHOMOGENEOUS GBBM EQUATIONS

The following initial-boundary value problem for the systems with multidimensional inhomogeneous generalized Benjamin-Bona-Mahony ( GBBM ) equations is reviewed. The existence of global attractors of this problem was proved by means of a uniform priori estimate for time.     

Generalized homogeneous functions and the two-body problem

IntroductionInthispaper,wegeneralizetheclassicconceptofhomogeneousfunctionofdegreeαandwestudytherelationbetweenthehomogeneousfunctionconceptandthemovementofabodythatsatisfiestheKepler’ssecondlaw .Asanapplicationoftheinvolvedtechniquesthatwereused ,wepresentasolutionofthetwo_bodyproblem ,givingawaytoobtainatimeequationforthebodythatrotatesaroundtheother,usingtheconceptofhomogeneousfunction .WeobtainedaserieslikeasthatwaspresentedinRef.[1 ] .1　GeneralizedHomogeneousFunctionsLetUbeanopensub…     

具有刚性双边裂纹的压电介质中的电荷相互作用分析

利用Stroh方法,研究了含双边固定导电裂纹的二维压电体在广义线力作用下的Green函数．首先分析的是因压电性和边界极化电荷所引起的作用在自由电荷上的Coulomb力．然后,再分析了双边裂纹附近的两个奇异点之间的相互作用问题（其中,至少一个奇异点处存在自由电荷）．数值计算表明:当两个或多个奇点互相靠近且奇点中至少存在一个自由电荷时,Coulomb力将明显影响压电介质内的力电场,这时的Coulomb力将不能再被忽略掉．所得结果不仅适用于平面和反平面问题,也适用于面内变形与面外变形相耦合的情况．     

Au2、Au3小团族分子的结构和势能函数

原子团簇的结构和性质研究是当今物理学和材料学中的一个热门课题,过渡金属团簇特别是Au团簇,由于其独特的物理和化学性质而被广泛地应用于催化反应、材料吸附[1-2]和光的吸收中[3]。近年来,人们用不同的理论方法研究金原子团簇。H儯kkinen等人利用GGA方法研究了中性和阴离Au2-10团簇的性质[4];Bravo-P啨rez等人采用从头计算的HF和post-HF方法研究Au2-Au6小团簇[5],这些计算结果与实验值相比,相差较大。由于金团簇电子结构的复杂性,对Au体系考虑旋—轨耦合和电子相关效应是很重要的,这种计算的不确定性对Au的影响比IB簇的其它金属团…     

New Method for Finding a Series of Exact Solutions to Generalized Breaking Soliton Equation

In this paper, a new generalized extended tanh-function method is presented for constructing soliton-like,period-form solutions of nonlinear evolution equations (NEEs). This method is more powerful than the extended tanhfunction method [Phys. Left. A 277 (2000) 212] and the modified extended tanh-function method [Phys. Left. A 285 (2001) 355]. Abundant new families of the exact solutions of Bogoyavlenskii‘s generalized breaking soliton equation are obtained by using this method and symbolic computation system Maple.     

Quark Energy Loss and Shadowing in Nuclear Drell-Yan Process

The energy loss effect in nuclear matter is another nuclear effect apart from the nuclear effects on the parton distribution as in deep inelastic scattering process. The quark energy loss can be measured best by the nuclear dependence of the high energy nuclear Dre11-Yan process. By means of three kinds of quark energy loss parameterizations given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Dre11-Yan production cross sections are analyzed for 800 GeV proton incident on a variety of nuclear targets from FNAL E866. It is shown that our results with considering the energy loss effect are much different from those of the FNAL E866, who analyzes the experimental data with the nuclear parton distribution functions obtained by using the deep inelastic IA collisions and pA nuclear Drell-Yan data. Considering the existence of energy loss effect in Drell-Yan lepton pairs production, we suggest that the extraction of nuclear parton distribution functions shoul““““d not include Dre11-Yan experimental data.