立体矩阵论初步(Ⅱ)——单位体阵与体阵的逆

本文是立体矩阵论初步(Ⅰ)—体阵的加法、乘法、数乘、转置和么体阵的续篇,讨论单位体阵与体阵的逆,将平面矩阵的相应内容处理成其特殊情况。

粘性泥石流体应力过冲特征与阵性流形成机理初探

本文应用最新研制的大型平板旋转式泥石流流变仪 ,对粘性泥石流体的应力应变特性进行测定 ,发现含有砾石的粘性泥石流体启动时具有明显的应力过冲现象。这种应力过冲特征 (Ty3>Ty2 )是与粘性介质阻力形成初期的剪切稀化和高浓度粗细颗粒组合形成的挤压内摩擦力共同组成的泥石流体应力滞后特征 (抗剪强度 )有关。根据这种应力过冲特征 ,通过剪切面上粘性泥石流体启动高度的推导 ,以及粘性泥石流体准静摩擦角 ,正压力 ,动摩擦系数的测定和演算 ,对比其粘性泥石流体阵性流计算值和观察值 ,基本相似 ,平均相对误差为 - 5 .43× 10 - 3。该项研究为进一步进行粘性泥石流体的模糊研究奠定了基础。

体上列满秩阵的若干等价形式

本文刻画了体上列满秩阵,给出16个等价形式,推广了域的情形。

载人航天器体装太阳电池阵有效发电面积计算方法

航天器的发电能力与太阳电池阵有效发电面积成正比。针对圆柱形载人航天器,提出了一种体装太阳电池阵有效发电面积计算方法。首先,将太阳电池阵沿圆周方向划分为多个子阵,通过坐标变换,计算太阳矢量与每个子阵法线的夹角(即太阳入射角);然后,将每个子阵面积与对应太阳入射角的余弦相乘并求和,得到体装太阳电池阵的有效发电面积。对不同轨道日照角、不同飞行姿态下体装太阳电池阵有效发电面积进行仿真分析,仿真结果表明:三轴对地姿态下平均有效发电面积为安装面积的25%~32%,通过固定角度偏航可将有效发电面积提高至安装面积的30%~44%。

神经系统副肿瘤综合征中的肌阵挛

1940年，Guichard等Ⅲ首次使用“副肿瘤”一词来描述一位子宫肿瘤患者由于肿瘤引起的多发性颅神经病。目前认为副肿瘤综合征（paraneoplasticsyndrome）是指由肿瘤分泌的功能性肽类、激素以及肿瘤与宿主间发生反应引起的疾病。

非线性函数三次型逼近算法研究

为提高函数逼近的精度,扩展二次型的适用范围,对二次型及矩阵的概念及运算方法进行了推广,提出了三次型及体阵的概念和运算方法,给出了多元函数梯度、黑塞矩阵,特别是多元函数泰勒公式的新的矩阵表达式,为二次型的进一步深入研究提供了新的基础,为函数逼近,最优化等方面的研究提供了一个新的视角,使得已有的特征值,特征向量等有可能被进一步推广从而使二次型的研究及应用得到极大的扩展,对于控制问题、优化问题的研究具有潜在的应用价值。

浮游界限速度的求解方法研究

以固体颗粒在加速过程中发生的动量传递为出发点,确定了相互发生动量交换的清水、固体颗粒的质量及其速度变化量,及影响其动量变化的外界因素.通过理论分析建立了水平管道内各种速度之间的关系,并与推移质层厚度联合起来,根据推移质层厚度的变化确定浮游界限速度,并通过大量的实验验证了该方法得到的浮游界限速度比其他经验公式得到的浮游界限速度具有更广泛的适用性及准确、可靠性.

Some studies on finding the nearest volume-preserving matrix

Finding the nearest volume-preserving matrix for a given matrix is studied. Amatrix equation is first obtained, which is a necessary condition for the solution to the problem.Then the equation is solved by the singular value decomposition method. Some additional results arealso provided to further characterize the solution. Using these results, a numerical algorithm isintroduced and a numerical test is given to illustrate the effectiveness of the algorithm.

FREE VIBRATION ANALYSIS AND PHYSICAL PARAMETER IDENTIFICATION OF NON-UNIFORM BEAM CARRYING SPRING-MASS SYSTEMS

To analyze a multibody system composed of non-uniform beam and spring-mass subsystems, the model discretization is carried on by utilizing the finite element method（FEM）, the dynamic model of non-uniform beam is developed by using the transfer matrix method of multibody system（MS-TMM）, the transfer matrix of non-u- niform beam is derived, and the natural frequencies are computed. Compared with the numerical assembly method （NAM）, the results by MS-TMM have good agreement with the results by FEM, and are better than the results by NAM. When using the high precision method, the global dynamic equations of the complex multibody system are not needed and the orders of involved system matrices are decreased greatly. For the investigation on the re- verse problem of the physical parameter identification of multibody system, MS-TMM and the optimization tech- nology based on genetic algorithms（GAs） are combined and extended. The identification problem is exchanged for an optimization problem, and it is formulated as a global minimum solution of the objective function with respect to natural frequencies of multibody system. At last, the numerical example of non-uniform beam with attach- ments is discussed, and the identification results indicate the feasibility and the effectivity of the proposed aop- proach.

Approximate querying between heterogeneous ontologies based on association matrix

An approximate approach of querying between heterogeneous ontology-basedinformation systems based on an association matrix is proposed. First, the association matrix isdefined to describe relations between concepts in two ontologies. Then, a methodof rewriting queriesbased on the association matrix is presented to solve the ontology heterogeneity problem. Itrewrites the queries in one ontology to approximate queries in another ontology based on thesubsumption relations between concepts. The method also uses vectors to represent queries, and thencomputes the vectors with the association matrix; the disjoint relations between concepts can beconsidered by the results. It can get better approximations than the methods currently in use, whichdonot consider disjoint relations. The method can be processed by machines automatically. It issimple to implement and expected to run quite fast.

STUDY ON THE COMPENSATION TECHNIQUE OF POSITIONING ERRORS FOR NC MACHINE TOOLS

Through analysis of the basic transformation of a typical body,the error transformations of the position vector and the displacement vector are employed,a general model for positioning errors of NC machine tools by using kinematics of the multi body system is discussed.By means of 8031 single chip system,intelligent error compensation controller has been developed.The results of experiments on XH714 machining center show that the positioning accuracy is enhanced effectively by more than 50%.

ADAPTIVE FLOW SOLUTION BASED ON MATRIX ERROR

An adaptive method for the solution of compressible flows is described. The idea results from the desire for an efficient grid system,and an accurate and robust solution method are used to resolve flow features of the interest. The adaptation flow solution is proposed,including the detection of flow features based on the matrix error; the mesh adaptation using the mesh movement,the mesh refinement,the mesh coarsening,and their combination. The feature detection based on the matrix error can maintain the high resolution property for shock waves of the one-dimensional approximate Riemann solver and the higher order reconstruction scheme. The high grid efficiency is obtained with the anisotropically directional grid corresponding to feature directions,and the error of the flow-field is averaged. The procedure and its application to flow solutions of shock waves are described. Results validate that the method is reliable.

Greedy calibration method for binocular camera system via characteristic homography matrix

A plane-based and linear camera calibration technique without considering lens distortion is proposed in a greedy and intuitive framework for the binocular camera system. Characteristic homography matrix and consistency constraints in close range are employed in this calibration. First, in order to calculate the internal geometries of the cameras, total least-square fitting as a robust tool for the geometrical cost function is exploited to recover the accurate principal point of each camera from all the characteristic lines of the homography matrices for all model planes. Secondly, generic prior knowledge of the aspect ratio of pixel cells is incorporated into the system to obtain the exact principal length in each camera. Thirdly, extrinsic geometries are accurately computed for all planar patterns with respect to each monocular camera. Finally, the rigid displacement between binocular cameras can be obtained by imposing the consistency constraints in 3-space geometry. Both simulation and real image experimental results indicate that reasonably reliable results can be obtained by this technique. And the proposed method is sufficient for applications where high precision is not required and can be easily performed by common computer users who are not experts in computer vision.

STABILITY ANALYSIS AND COOPERATIVE CONTROL OF DISTRIBUTED MULTI-AGENT SYSTEM WITH SAMPLED COMMUNICATION

The cooperative control and stability analysis problems for the multi-agent system with sampled com- munication are investigated. Distributed state feedback controllers are adopted for the cooperation of networked agents. A theorem in the form of linear matrix inequalities（LMI） is derived to analyze the system stability. An- other theorem in the form of optimization problem subject to LMI constraints is proposed to design the controller, and then the algorithm is presented. The simulation results verify the validity and the effectiveness of the pro- posed approach.

The Metapositive Definite Self－Conjugate Solution of the Matrix Equation AXB＝C over a Skew Field

Let F be the strong p-division ring [4]. This paper is sequel to [1]. Metapositive definite self-conjugate matrix over F is defined and the necessary and sufficient conditions for determining whether a partitioned matrix over F is metapositive definite self-conjugate are given.Moreover,a decomposition of pairwise matrices over F with the same numbers of columns is also presented. Whence some necessary and sufficient conditions for the existence of and the explicit expression for the metapositive definite self-conjugate solution of the matrix equation AXB=C over F are derived.

Minor Self-conjugate and Skewpositive Semidefinite Solutions to a System of Matrix Equations over Skew Fields

Minor self conjugate (msc) and skewpositive semidefinite (ssd) solutions to the system of matrix equations over skew fields [A mn X nn =A mn ,B sn X nn =O sn ] are considered. Necessary and sufficient conditions for the existence of and the expressions for the msc solutions and the ssd solutions are obtained for the system.

Identification of colorectal cancer metastasis markers by an angiogenesis-related cytokine-antibody array

AIM： To investigate the angiogenesis-related protein expression profile characterizing metastatic colorectal cancer （mCRC） with the aim of identifying prognostic markers.METHODS： The expression of 44 angiogenesis- secreted factors was measured by a novel cytokine antibody array methodology. The study evaluated vas- cular endothelial growth factor （VEGF） and its soluble vascular endothelial growth factor receptor （sVEGFR）-I protein levels by enzyme immunoassay （EIA） in a panel of 16 CRC cell lines, mRNA VEGF and VEGF-A isoforms were quantified by quantitative reverse-transcription polymerase chain reaction （Q-RT-PCR） and vascular en- dothelial growth factor receptor （VEGFR）-2 expressionwas analyzed by flow cytometry.

Preparation and Characterization of Fe Nanowire Arrays Embedded in Porous Anodic Aluminum Oxide Templates

Fe nanowire arrays are prepared by electrodeposition in porous anodic aluminum oxide template from a composite electrolyte solution. These nanowires have an uniform diameter of approximate 25 nm and a length in excess of 2.5 μm. The micrographs and crystal structures of Fe nanowires are studied by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction(XRD). It is found that each nanowire is essentially a single crystal and has a different orientation in each array. Hysteresis loops of Fe nanowire array show that its easy magnetization direction is perpendicular to the sample plane.

On a Matrix Equation AX+XB=C over a Skew Field

In this paper we study a matrix equation AX+BX=C(I)over an arbitrary skew field,and give a consistency criterion of(I)and an explicit expression of general solutions of(I).A convenient,simple and practical method of solving(I)is also given.As a particular case,we also give a simple method of finding a system of fundamental solutions of a homogeneous system of right linear equations over a skew field.