单相超导体 CaLaBaCu3-x B x O 7-δ 正常态热电势率研究

从 77K到 300K之间对 CaLaBaCu3-x B x O7-W单相体系的正常态热电势率进行了微分法测量 ,发现 随着硼含量 x 从 0向 0. 4的逐步增加 ,样品体系正常态特性从金属性向类半导体性质转变 ,其主要载流 子由空穴型为主转变为电子型为主 .根据以上的性质转变 ,我们采用双带模型及半导体模型对 x 的不同 值进行曲线模拟 ,拟合的热电势率 — 温度曲线与实验曲线相当吻合 ,同时根据模型对样品的费米能及 有效能隙进行了计算 .     

Common Principal Components for Dependent Random Vectors

Let the kp-variate random vector X be partitioned into k subvectors X_i of dimension p each, and let the covariance matrix Ψ of X be partitioned analogously into submatrices Ψ_ij. The common principal component (CPC) model for dependent random vectors assumes the existence of an orthogonal p by p matrix β such that β^tΨ_ijβ is diagonal for all (i, j). After a formal definition of the model, normal theory maximum likelihood estimators are obtained. The asymptotic theory for the estimated orthogonal matrix is derived by a new technique of choosing proper subsets of functionally independent parameters.     

A Determinant Representation for the Distribution of Quadratic Forms in Complex Normal Vectors

Let the column vectors of X:: M×N, M<N, be distributed as independent complex normal vectors with the same covariance matrix Σ. Then the usual quadratic form in the complex normal vectors is denoted by Z=XLX^H where L: N×N is a positive definite hermitian matrix. This paper deals with a representation for the density function of Z in terms of a ratio of determinants. This representation also yields a compact form for the distribution of the generalized variance |Z|.     

Generalized equivalence of pairs of matrices

Pairs (A₁B₁) and (A₂B₂) of matrices over a principal ideal domain R are called the generalized equivalent pairs if A₂=UA₁V₁B₂=UB₁V₂ for some invertible matrices UV₁V₂ over R. A special form is established to which a pair of matrices can be reduced by means of generalized equivalent transformations. Besides necessary and sufficient conditions are found, under which a pair of matrices is generalized equivalent to a pair of diagonal matrices. Applications are made to study the divisibility of matrices and multiplicative property of the Smith normal form.     

Quasi-periodic Solutions of the General Nonlinear Beam Equations

In this paper,one-dimensional (1D) nonlinear beam equations of the form utt - uxx + uxxxx + mu = f(u)with Dirichlet boundary conditions are considered,where the nonlinearity f is an analytic,odd funct...     

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In this paper, we study the stochastic comparisons of order statistics from generalized normal distributions. We obtain some sufficient conditions for ordering results based on parameter matrix and vector majorization comparisons. These conditions are necessary in some cases.     

The influence of a weak signal seed-wave on picosecond supercontinuum generation in photonic crystal fiber

We present a numerical study of the properties of picosecond supercontinuum (SC) generation when pumping in the normal dispersion region of photonic crystal fibers. Simulation results demonstrate that rogue wave generation can be reduced by adding a weak signal continuous-wave (CW) seed on the main pump pulse. Besides, the red-shifted part of SC exhibits higher degree of coherence and pulse-to-pulse intensity stability.     

Quantum Birkhoff-Gustavson normal form in some completely resonant cases

The goal of this paper is to present an explicit computation of the Birkhoff-Gustavson normal form in the 1:1, 1:2 and 1:3 resonances, by using the concept of Weyl quantization, especially when it is about the first terms. We use in particular the Weyl symbolic calculus and the abstract theorem of the quantum Birkhoff-Gustavson normal form in infinite dimension.