有限维向量空间中基的选取

有限维向量空间中选取基时需注意三个因素:1.用基体现子空间之间的关系;2.使线性变换对应的基矩阵比较简单;3.以逐次扩充的方式选取基.     

Expression of matrix metalloproteinase-9 in nasopharyngeal carcinoma and association with Epstein-Barr virus infection

Objective: To evaluate the expression of matrix metalloproteinase-9 (MMP9) in nasopharyngeal carcinoma and the association between MMP9 and Epstein-Barr virus infection. Methods: The MMP9 expression was studied by immunohistochemical analysis; and Epstein-Barr virus encoded small nuclear mRNA-1 (EBER-1) produced by in situ hybridization were examined in 41 nasopharyngeal carcinoma sections, and the relation between them, and the associations of MMP9 with clinical features were statistically analyzed. Results: Positive expression rate of MMP9 was 73.17%. The expression of MMP9 showed significant positive correlation with the expression of EBER- 1 (γ=0.483, P=0.001). There was significant association of MMP9 expression with lymph nodes metastasis and clinical stage (P＜0.001), non-significant association with age, gender, pathological classification and T classification. Conclusions: The highly pronounced expression of MMP9 is associated with cervical lymph nodes metastasis. Epstein-Barr virus can enhance NPC metastasis by up-regulating the expression of MMP9.     

基于FPGA的频率计电路设计

本文介绍了数字频率计设计的基本原理,对频率计所采用各种硬件除法进行了比较,提出了倍频计数法测量数字高频的实现方案,并给出了频率计设计的硬件电路原理和软件实现,结果表明这种方法实现了频率计的高速和高精度。     

Passive fuzzy controller design for nonlinear systems with multiplicative noises

This paper proposes a passive fuzzy controller design methodology for nonlinear system with multiplicative noises. Applying the Itô's formula and the sense of mean square, the sufficient conditions are developed to analyze the stability and to design the controller for stochastic nonlinear systems which are represented by the Takagi-Sugeno (T-S) fuzzy models. The sufficient conditions derived in this paper belong to the Linear Matrix Inequality (LMI) forms which can be solved by the convex optimal programming algorithm. Besides, the passivity theory is applied to discuss the effect of external disturbance on system. Finally, some numerical simulation examples are provided to demonstrate the applications of the proposed fuzzy controller design technique.     

浅析图书馆的馆员队伍建设

图书馆馆员队伍是图书馆的人力资源,而人力资源可谓一个项目的基石,所以馆员队伍建设在图书馆建设中处于非常重要的地位。本文通过对在建设和谐社会背景下囹书馆现阶段发展形势及读者多元化需求的分析,指出图书馆不合理的馆员队伍结构,从而提出在当前应读者需求的馆员队伍建设的相关对策。     

求解奇异线性方程组的双逐次投影法

用双逐次投影迭代法来求解奇异线性方程组,当线性方程组的系数矩阵是对称半正定时,给出了不同情形时有关参量的选取以及相应的算法,并就收敛结果分别与雅可比迭代法和Gauss-Seidel迭代法进行了比较,数值结果表明,该方法对求解奇异线性方程组是很有效的.     

Using diagrams as tools for the solution of non-routine mathematical problems

The Mathematics education community has long recognized the importance of diagrams in the solution of mathematical problems. Particularly, it is stated that diagrams facilitate the solution of mathematical problems because they represent problems’ structure and information (Novick & Hurley, 2001; Diezmann, 2005). Novick and Hurley were the first to introduce three well-defined types of diagrams, that is, network, hierarchy, and matrix, which represent different problematic situations. In the present study, we investigated the effects of these types of diagrams in non-routine mathematical problem solving by contrasting students’ abilities to solve problems with and without the presence of diagrams. Structural equation modeling affirmed the existence of two first-order factors indicating the differential effects of the problems’ representation, i.e., text with diagrams and without diagrams, and a second-order factor representing general non-routine problem solving ability in mathematics. Implicative analysis showed the influence of the presence of diagrams in the problems’ hierarchical ordering. Furthermore, results provided support for other studies (e.g. Diezman & English, 2001) which documented some students’ difficulties to use diagrams efficiently for the solution of problems. We discuss the findings and provide suggestions for the efficient use of diagrams in the problem solving situation.     

A simplified MMSE-based iterative receiver for MIMO systems

A simplified minimum mean square error （MMSE） detector is proposed for joint detection and decoding of multiple-input multiple-output （MIMO） systems. The matrix inversion lemma and the singular value decomposition （SVD） of the channel matrix are used to simplify the computation of the coefficient of the MMSE filter. Compared to the original MMSE detector, the proposed detector has a much lower computational complexity with only a marginal performance loss. The proposed detector can also be applied to MIMO systems with high order modulations.     

蛋白质loop区域闭合数值方法分析与比较

针对蛋白质loop区域的闭合问题,比较分析了两种来源于机器人学的数值方法——循环坐标下降法（CCD）和雅可比矩阵方法,进行了实现并设计实验。在计算时间和闭合效率方面循环坐标下降法要明显优于雅可比矩阵方法,而雅可比矩阵方法则可以较平均地改变每一个二面角值。     

基于ICCE-IC的中国产业发展及减排策略研究

从宏观层面综合评价某一国家或地区的产业碳排放及其影响力,系统地提出产业低碳经济发展策略,已经成为一项关键工作。本文在投入产出模型和生态投入产出模型的基础上,提出了产业碳排放影响力系数-产业影响力系数(ICCE-IC)矩阵理论,根据象限分布将产业划分为高排放/高影响、高排放/低影响、较高排放/高影响、较高排放/低影响、低排放/高影响、低排放/低影响6种类型,并分别界定低碳经济发展策略;利用我国2007年投入产出表和按行业分能源消费量,分析我国43个产业部门二氧化碳排放量的ICCE-IC组合矩阵分布结构,研究和探索既可降低碳排放、又能保持经济稳定增长的产业结构调整策略。