概念内涵和外延关系的再认识

形式逻辑提出概念的内涵和外延之间具有反变关系,辩证逻辑则认为概念的内涵和外延之间还有正变关系。“反变关系”、“正变关系”各有其应用的语境。在实践中,存在着在形式逻辑的框架下解释“正变关系”、“正变关系”的适用范围不确定以及不能用“反变关系”或“正变关系”解释的一些例外现象。为了正确认识概念内涵和外延的关系,需要对它们进行分析。

Monotonicity of the tail dependence for multivariate t-copula

This paper considers the upper orthant and extremal tail dependence indices for multivariate t-copula. Where, the multivariate t-copula is defined under a correlation structure. The explicit representations of the tail dependence parameters are deduced since the copula of continuous variables is invariant under strictly increasing transformation about the random variables, which are more simple than those obtained in previous research. Then, the local monotonicity of these indices about the correlation coefficient is discussed, and it is concluded that the upper extremal dependence index increases with the correlation coefficient, but the monotonicity of the upper orthant tail dependence index is complex. Some simulations are performed by the Monte Carlo method to verify the obtained results, which are found to be satisfactory. Meanwhile, it is concluded that the obtained conclusions can be extended to any distribution family in which the generating random variable has a regularly varying distribution.

Research on 1-3 Orthogonal Anisotropic Piezoelectric Composite Material Sensors-

Piezoelectric composite material (PCM) is an important branch of modernsensor and actuator materials with wide applications in smart structures. In this paper, based onpiezoelectric ceramic, composite and experimental mechanics theories, a kind of 1-3 orthogonalanisotropic PCM (OAPCM) sensor is developed, and the sensing principle is analyzed to describesensor behaviors. In order to determine strain and stress on isotropic or orthogonal anisotropiccomponent surface, the relationships between strain and stress are established. The experimentalresearch on 1-3 OAPCM sensor is carried out in uniaxial and biaxial stress states. The results showthat 1-3 OAPCM sensors offer orthotropic properties of piezoelectricity, and sensing equations canbe used for strain or stress measurement with good accuracy.

Corporate Governance and Earnings Quality： The Experience of Listed Companies in Iran

This study examines the relationship among independent boards of directors, board size, managerial share ownership （MSO）, and earnings quality. The study of these relationships is controlled by firm size based on a sample of 114 companies listed on the Tehran Stock Exchange （TSE） for the period from 2008 to 2010. The results demonstrate that there was an insignificant positive relationship among independent boards of directors, managerial ownership, and earnings quality. Subsequent analysis shows an insignificant negative relationship between board size and earnings quality. It also provides evidence of the negative relationship between firm size as a control variable and earnings quality. This can be attributed to the fact that large firms are claimed to be politically sensitive and thus have the incentive to lessen variances in changes in their reported earnings.

Dynamic bivariate normal copula

Normal copula with a correlation coefficient between-1 and 1 is tail independent and so it severely underestimates extreme probabilities. By letting the correlation coefficient in a normal copula depend on the sample size, H¨usler and Reiss(1989) showed that the tail can become asymptotically dependent. We extend this result by deriving the limit of the normalized maximum of n independent observations, where the i-th observation follows from a normal copula with its correlation coefficient being either a parametric or a nonparametric function of i/n. Furthermore, both parametric and nonparametric inference for this unknown function are studied, which can be employed to test the condition by H¨usler and Reiss(1989). A simulation study and real data analysis are presented too.

General compliance transformation relations for all seven crystal systems

For crystals, the compliance (sij) and the stiffness (cij) matrices are specified in the orthogonal coordinate systems (Yi), which do not coincide with the crystal axes (Xi) commonly used except for cubic and orthorhombic crystal systems. Transformations have been done in this paper and the general compliance transformation relations from the orthogonal coordinate systems (Yi) to the measurement systems (Mi) are given for all seven crystal systems. Accordingly, useful expressions for Young's modulus E and Poisson's ratio are also derived.

The design, synthesis and α7 nicotinic acetylcholine receptors positive allosteric modulative evaluation of 3H-quinazolin-4-one derivatives

A series of new 6-substituted 3 H-quinazolin-4-ones（3 a-3 d） were designed, synthesized and evaluated as the type I positive allosteric modulators（PAMs） of human α7 n ACh R expressed in Xenopus ooctyes by two-electrode voltage clamp. However, no compound showed a better efficacious PAM than lead compound 2 in the presence of acetylcholine（100 μM）. The structure-activity relationship（SAR） analysis suggested that thiazolo[4,5-d]pyrimidin-7（6 H）-one was the key biological skeleton.