Degasperis-Procesi方程解的渐进性质

主要研究Degasperis-Procesi(DP)方程强解的渐近性质,即通过对其强解的动量密度用渐近密度的方法,并在渐近密度唯一的假定下,证实了DP方程的正动量密度的渐进密度是支集在正轴上的Dirac测度的组合,且当时间趋于无穷时,动量密度集中在不同速度向右移动的小区域中.     

若干矩阵Г分布的相关分布

本文研究了与矩阵Г分布相关的若干分布的密度函数，利用矩阵Г分布的特征函数和它的Bartlett分解等方法，获得了与矩阵Г分布相关的几个分布的密度函数解析表达式，它们包括Г分布随机矩阵的子矩阵、行列式、迹和特征根的分布密度，进一步还得到了相关系数矩阵的分布密度函数形式．     

直圆管突扩通道内宾汉流体湍流流场的数值研究

本文依据牛顿流体中建立的标准ｋ＿ε湍流模型这一基本思想，考虑宾汉流体的本构方程，建立了适用于求解宾汉流体湍流流动的控制方程·采用压力修正算法，实现了宾汉流体速度场与压力场的关联·在理论研究基础上，对直圆管突扩通道内宾汉流体湍流流动进行了数值研究，并探讨了直圆管突扩通道内宾汉流体湍流流动机理·     

小批量生产的贝叶斯质量控制模型

本应用贝叶斯统计推断方法，研究了基于正态共轭先验分布和正态——逆伽玛共轭先验分布的小批量生产下的质量控制模型问题，根据不同控制对象的预报分布密度函数，分别构造了方差已知时的贝叶斯均值控制图和方差未知时的贝叶斯均值——标准差控制图，并与经典质量控制模型进行了比较。     

Г分布密度函数的性质

分析了Г分布密度函数的性质，指出了该密度函数与相应参数之间的关系．主要研究第二个参数对密度的影响，证明了β增大时Г（α，β）分布密度极大值也增大，还指出了β变化时Г（α，β）分布密度与另一特定密度曲线交点的变化规律．     

一类具有阶段结构的捕食-食饵种群收获模型

本文研究了一类具有阶段结构和密度制约的捕食-食饵两种群同时收获模型.利用比较定理,Barbalt引理,极人值原理等,获得了平衡点稳定性的充分条件,以及在不同情况下,各种群以最大可持续收获量为管理目标的最优生存量和最大收获量.     

利用介孔材料制备碳纳米管的形貌、结构和Raman散射研究

以碳氢气体为反应物,利用化学气相沉积方法,在不同的衬底上制备了碳纳米管。研究了不同衬底对碳纳米管生长方式的影响。对碳纳米管的形貌和结构进行了观察研究,在介孔二氧化硅衬底上制备了取向生长的碳纳米管。碳纳米管具有很高的密度和纯度。研究了取向碳纳米管的Raman谱,分析了碳纳米管的Raman共振特性与其微观结构的关系。     

一类基于微分关系同时识别声速和密度的方法

1．引言本文考虑介质声速和密度的同时反演问题．利用脉冲平面波从不同的两个方向探测［1－5］，得到两组对应于不同入射角的表面响应信息，再由这两组响应信息来同时识别介质的声速和密度．关于介质声速和密度的同时反演，Coen［9－10］利用点源数据将问题转化为Schr6dinger方程的势函数反演．Howardl3］采用脉冲平面波探测，归结成一个向量MarchenkO积分方程．然而，这些方法都涉及求解Marchenko（gGelfdnd－Levitan）积分方程，不易在计算机上实现．关于介质参数的反演，张关泉作了不少工作【‘一句．其中在文献【司中对声速和密度的…     

p─范分布及其性质的研究

本文用较为简便的方法推导出一元及ｎ元ｐ─范分布的密度函数，研究了ｎ元，ｐ—范分布的几个性质．     

截断样本下的强率函数和密度函数核估计的渐进正态性

本文用[1]发展的计数过程去研究截断样本下强率函数核估计的渐进正态性．在弱于[7]和[10]的条件下，得到了更一般的结果．接着我们将这种方法运用到密度函数核估计，在较弱的条件下，得到了截断样本下密度函数核估计的渐进正态性．     

Creep of compact human bony tissue under tension

The behavior of compact bony tissue from a human tibia with time at various levels of a constant lengthwise stretching load has been studied. The limits of application of the linear viscoelastic theory for bony tissue have been established. Characteristics of the material have been determined which make it possible to describe both active and also retrograde creep.     

Modeling,analysis and simulation of the human femur: prosthesis of femur head

We report the results obtained when carrying out the analysis of the strengths and strains that take place when prosthesis of femur head are implanted in the human femur. The modeling is made with tools provided by Computer Aided Geometry Design, using Non Uniform Rational B-Splines representations (NURBS). In the analysis of the strengths and strains, produced in the bone-cement-prosthesis interaction, partial differential equations of the coupled system are obtained for the displacements and deformations, that allow to analyze cases of physical and biological loads, under which will be work the implants during their useful life, which also is estimated; because of the frequent phenomenon of bony absorption and the consequent relaxation and loss of the replacement surgery. The obtained equations are solved by finite element method, with the corresponding estimation of the obtained errors. The simulations will be performed using high level software able to show realistic visualizations of the observed phenomena in real time. The fracture of the femur neck is a frequently observed trauma and has taken to the authors to make the present work. The obtained results will allow to make the modeling, analysis and simulation of other bony structures and the implants of the corresponding prosthesis. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Simulation of the sinus floor elevation

In order to anchor implants in the severely atrophic maxilla, the method of sinus floor elevation has been introduced about ten years ago. For this purpose the bony support is extended into the sinus floor by filling it up with bone graft. It was not clear yet which degree of maturation the augmented bone must reach to distinctly reduce stress peaks in the bony structures. The results of this FE‐study show that it seems to be essential for the bone graft to attain at least the stiffness of cancellous bone. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Resistance of bony tissue to tensile fracture

The tensile fracture resistance of compact bony tissue is considered. The relation between specific strain energy and stress level is established. A strength criterion characterizing the degree of deformation is proposed on the basis of a model, according to which compact bony tissue may be regarded as a composite material. The mode of variation of the proposed resistance parameter over the various zones of the cross section of the diaphysis of a human tibia has been experimentally established.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1084–1091, November–December, 1971.     

A hydrodynamic model of human cochlea

A two-compartment model of the human cochlea is proposed. When stretched out, the bony spiral tube looks like two chambers separated by a membrane. Both chambers are filled with viscous fluid called perilymph; they communicate with one another via a canal. Sound vibrations enter the cochlea through the oval window and cause periodic change of pressure in the perilymph, which, in turn, causes the membrane to vibrate. The motion of the fluid is described by hydrodynamic equations, which are supplemented with the membrane vibration equation. The equations are linearized in the amplitude of the vibrations, and their solution is sought in the form of Fourier harmonics with a given frequency. To determine the harmonics, a system of linear boundary value problems for ordinary differential equations with variable coefficients is obtained. The numerical solution of this system using finite difference method fails because it involves a large parameter and the problem is close to a singular one. We propose a novel numerical method without saturation that enables us to obtain solutions in a wide range of frequencies up to an arbitrary and controllable accuracy. The computations confirm the Bekesy theory stating that high-frequency sounds cause the membrane to bend near the apex of the cochlea, and low-frequency sounds cause it to bend near the base of the cochlea.     

The Conditional-Potts Clustering Model

This article presents a Bayesian kernel-based clustering method. The associated model arises as an embedding of the Potts density for class membership probabilities into an extended Bayesian model for joint data and class membership probabilities. The method may be seen as a principled extension of the super-paramagnetic clustering. The model depends on two parameters: the temperature and the kernel bandwidth. The clustering is obtained from the posterior marginal adjacency membership probabilities and does not depend on any particular value of the parameters. We elicit an informative prior based on random graph theory and kernel density estimation. A stochastic population Monte Carlo algorithm, based on parallel runs of the Wang–Landau algorithm, is developed to estimate the posterior adjacency membership probabilities and the parameter posterior. The convergence of the algorithm is also established. The method is applied to the whole human proteome to uncover human genes that share common evolutionary history. Our experiments and application show that good clustering results are obtained at many different values of the temperature and bandwidth parameters. Hence, instead of focusing on finding adequate values of the parameters, we advocate making clustering inference based on the study of the distribution of the posterior adjacency membership probabilities. This article has online supplementary material.     

Non-asymptotic Bandwidth Selection for Density Estimation of Discrete Data

We propose a new method for density estimation of categorical data. The method implements a non-asymptotic data-driven bandwidth selection rule and provides model sparsity not present in the standard kernel density estimation method. Numerical experiments with a well-known ten-dimensional binary medical data set illustrate the effectiveness of the proposed approach for density estimation, discriminant analysis and classification. Supported by the Australian Research Council, under grant number DP0558957.     

Predicting stochastic characteristics of generalized eigenvalues via a novel sensitivity-based probability density evolution method

This paper proposes a novel numerical method for predicting the probability density function of generalized eigenvalues in the mechanical vibration system with consideration of uncertainties in structural parameters. The eigenproblem of structural vibration is presented by first and the sensitivity of generalized eigenvalues with respect to structural parameters can be derived. The probability density evolution method is then developed to capture the probability density function of generalized eigenvalues considering uncertain material properties. Within the proposed method, the probability density evolution equation for the generalized eigenvalue problem is established accounting for the sensitivity of generalized eigenvalues with respect to structural parameters. A new variable which connects generalized eigenvalues to structural parameters is then introduced to simplify the original probability density evolution equation. Next, the simplified probability density evolution equation is solved by using the finite difference method with total variation diminishing schemes. Finally, the probability density function as well as the second-order statistical quantities of generalized eigenvalues can be predicted. Numerical examples demonstrate that the proposed method yields results consistent with Monte-Carlo simulation method within significantly less computation time and the coefficients of variation of uncertain parameters as well as the total number of them have remarkable effects on stochastic characteristics of generalized eigenvalues.