地球、金星大气寿命的计算

假定行星大气层中气体分子的逃逸过程是准静态过程,推导出了气体分子的逃逸方程,定义了行星大气分子的逃逸率及行星大气的半寿命,给出了数学表达式.根据数学表达式,假定不同的大气温度,计算了地球和金星大气层的半寿命.结果表明,地球和金星大气层的半寿命远超过宇宙年龄(约1010y),因而是非常稳定的.本理论可应用于其他行星和月球大气层半寿命的计算.     

延展表面凝结液膜的动量积分方法

采用动量积分方法分析压水堆发生失水事故时在安全壳的内表面上的液膜凝结、再浸润和蒸发过程。由凝结液膜的质量和动量守恒方程导出了凝结液膜在延展表面的子午线方向平均速度的积分-微分方程。假设液膜以层流的方式流动，把导出的积分-微分方程变成容易进行数值积分的液膜速度的一阶常微分方程，由此求得液膜厚度分布。液膜能量守恒方程的解给出了安全壳内壁面的温度分布。     

Exploring Two-Wave Reciprocal Structural Relations Among Orthographic Knowledge, Phonological Sensitivity, and Reading and Spelling of English Words by Chinese Students.

In a 2-wave study of a cohort of 108 Chinese students (10- to 11-year-olds) learning English as a second language, the authors examined the relative effects of three Time 1 latent constructs-- orthographic knowledge, phonological sensitivity, and word identification (reading and spelling of regular and exception words)--on the respective Time 2 performance. The authors posited autoregressive effects, in which Time 1 constructs affected their matching Time 2 performance (e.g., Time 1 orthographic knowledge on Time 2 orthographic knowledge), as well as reciprocal cross-domain effects (e.g., orthographic knowledge on word identification and vice versa). The model converged to a proper solution with reasonably good fit. The results suggest (a) strong stability in the children's word identification and phonological sensitivity, (b) substantial effects of word identification on subsequent orthographic knowledge and phonological sensitivity, particularly the former; and (c) greater variations in individuals' growth of orthographic knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reflected Appraisals, Academic Self-Perceptions, and Math/Science Performance During Early Adolescence.

The authors tested a model of the relations among adolescents' perceptions of parents', teachers', and classmates' support for, valuing of, and beliefs about their competence in math/science; adolescents' own academic self-perceptions concerning math/science; and their academic performance. The sample included 378 middle school students; 65% were Latino, and 21% were European American. Reflected appraisals of adults' beliefs concerning both the importance of and students' competence in math/science, as well as perceived support, predicted students' own self-perceived importance, competence, scholastic behavior, and performance in these courses. Latino students reported lower mean levels of perceived competence than did European American students (controlling for maternal education). Findings have important implications for understanding achievement socialization in ethnically diverse populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Discrepancy in Analyses of the MSCEIT--Resolving the Mystery and Understanding Its Implications: A Reply to Gignac (2005).

Replies to comments made by G. E. Gignac (see record 2005-06671-010) on the current authors' original article (see record 2003-02341-015). Gignac reanalyzed the factor structure of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) and found results that differed from those the authors obtained initially. The authors tracked down the surprising sources of those discrepancies. G. E. Gignac's hierarchical model of emotional intelligence appears promising, and the authors anticipate that further investigations of the MSCEIT factor structure may yield additional information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

运动悬索的稳态构形与自振频率分析

考虑运动悬索速度的影响,建立了运动悬索动量方程,将此方程应用于稳定运动悬索,得到了稳定运动的速度-初始角函数关系和分叉条件,分析了运动悬索可能的曲线形状,指出了可能存在的不稳定现象和提高传动平稳性的途径.通过计算,得到了悬索的速度-初始角曲线.可根据速度-初始角方程和分叉条件,通过增加初始轴力等手段达到稳定运动目的.通过对运动悬索平面运动分析,得到了其非线性运动控制方程,定性分析了运动速度对悬索自振频率的影响.指出了当运动速度等于横向弹性波速度时系统将发生基频共振.     

改善辊型降低弯辊力提高工作辊轴承及轧辊使用寿命

论述了四辊可逆板带冷轧机较大的弯辊力对昂贵的轧辊及轧辊轴承使用寿命的影响,通过研究辊系的弹性变形曲线,找出合理辊系凸度曲线来降低弯辊力.     

Thermodynamic Properties of Methanol in the Critical and Supercritical Regions

The isochoric heat capacity of pure methanol in the temperature range from 482 to 533 K, at near-critical densities between 274.87 and 331.59 kg· m⁻³, has been measured by using a high-temperature and high-pressure nearly constant volume adiabatic calorimeter. The measurements were performed in the single- and two-phase regions including along the coexistence curve. Uncertainties of the isochoric heat capacity measurements are estimated to be within 2%. The single- and two-phase isochoric heat capacities, temperatures, and densities at saturation were extracted from experimental data for each measured isochore. The critical temperature (T_c = 512.78±0.02K) and the critical density (ρ_c = 277.49±2 kg · m⁻³) for pure methanol were derived from the isochoric heat-capacity measurements by using the well-established method of quasi-static thermograms. The results of the C_VVT measurements together with recent new experimental PVT data for pure methanol were used to develop a thermodynamically self-consistent Helmholtz free-energy parametric crossover model, CREOS97-04. The accuracy of the crossover model was confirmed by a comprehensive comparison with available experimental data for pure methanol and values calculated with various multiparameter equations of state and correlations. In the critical and supercritical regions at 0.98T_c≤ T ≤ 1.5T_c and in the density range 0.35ρ_c ≤ ρ leq 1.65 ρ_c, CREOS97-04 represents all available experimental thermodynamic data for pure methanol to within their experimental uncertainties.     

An advanced numerical method for computing elastodynamic fracture parameters in functionally graded materials

A new meshless method for computing the dynamic stress intensity factors (SIFs) in continuously non-homogeneous solids under a transient dynamic load is presented. The method is based on the local boundary integral equation (LBIE) formulation and the moving least squares (MLS) approximation. The analyzed domain is divided into small subdomains, in which a weak solution is assumed to exist. Nodal points are randomly spread in the analyzed domain and each one is surrounded by a circle centered at the collocation point. The boundary-domain integral formulation with elastostatic fundamental solutions for homogeneous solids in Laplace-transformed domain is used to obtain the weak solution for subdomains. On the boundary of the subdomains, both the displacement and the traction vectors are unknown generally. If modified elastostatic fundamental solutions vanishing on the boundary of the subdomain are employed, the traction vector is eliminated from the local boundary integral equations for all interior nodal points. The spatial variation of the displacements is approximated by the MLS scheme.     

A boundary element-free method (BEFM) for three-dimensional elasticity problems

This study combines the boundary integral equation (BIE) method and improved moving least-squares (IMLS) approximation to present a direct meshless boundary integral equation method, the boundary element-free method (BEFM) for three-dimensional elasticity. Based on the improved moving least-squares approximation and the boundary integral equation for three-dimensional elasticity, the formulae of the boundary element-free method are given, and the numerical procedure is also shown. Unlike other meshless boundary integral equation methods, the BEFM is a direct numerical method in which the basic unknown quantity is the real solution of the nodal variables, and the boundary conditions can be applied directly and easily, thus giving it a greater computational precision. Three selected numerical examples are presented to demonstrate the method.Aknowledgement The work in this project was fully supported by a grant from the Research Grants Council (RGC) of the Hong Kong Special Administrative Region, China (Project No. CityU 1011/02E).The work that is described in this paper was supported by Project No. CityU 1011/02E, which was awarded by the Research Grants Council of the Hong Kong Special Administrative Region, China. The authors are grateful for the financial support.