Damage and fracture evaluation of granular composite materials by digital image correlation method

This paper presents the applications of digital image correlation technique to the mesoscopic damage and fracture study of some granular based composite materials including steelfiber reinforced concrete, sandstone and crystal-polymer composite. The deformation fields of the composite materials resulted from stress localization were obtained by the correlation computation of the surface images with loading steps and thus the related damage prediction and fracture parameters were evaluated. The correlation searching could be performed either directly based on the gray levels of the digital images or from the wavelet transform (WT) coefficients of the transform spectrum. The latter was developed by the authors and showed higher resolution and sensitivity to the singularity detection. Because the displacement components came from the rough surfaces of the composite materials without any coats of gratings or fringes of optical interferometry, both surface profiles and the deformation fields of the composites were visualized which was helpful to compare each other to analyze the damage of those heterogeneous materials. The project supported by the National Natural Science Foundation of China (10125211 and 10072002), the Scientific Committee of Yunnan Province for the Program of Steel Fiber Reinforced Concrete, and the Institute of Chemical Materials, CAEP at Mianyang     

Quantum-Chemical Evaluation of the Protolytic Properties of Thiophenols

The enthalpies and free energies of proton affinity (PA) were calculated by the PM3 method for 27 thiophenoxide anions. For thiophenols, linear correlation has been found between the PAs and the values of pK _a measured by different authors in aqueous acetone, aqueous ethanol, and methanol media. The dependences found permit one to predict a priori the protolytic properties of thiophenols. The differential effects of aqueous ethanol media with different ethanol contents on thiophenol acidity were evaluated based on quantum-chemical data.Original Russian Text Copyright © 2004 by A. N. Pankratov and A. V. Shalabai__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 800–806, September–October, 2004.     

对五棵树开发区区域环境的研究

通过对建设五棵树开发区周边环境状况影响评价，指出影响环境因素。根据周边环境质量现状，给出建立综合治理污染措施及手段，并对开发区建设后的生态适宜性进行了研究。     

浅谈跨国投资项目的评估

论述了跨国投资项目评估的特殊性,列举了项目财务评估的种类和常用方法。     

关于网络环境下体育教育专业社会评价的思考

社会评价是教育评价的重要组成部分.利用传统体育教育专业社会评价工作流程图,指出传统体育教育专业社会评价的不足,并在探讨基于网络环境体育教育专业社会评价的优势、构建原则的基础上,试图设计出网络环境下体育教育专业社会评价体系,以期为完善体育教育专业社会评价体系提供理论参考与借鉴.     

关于整理高校评估档案材料的几点思考

随着高校本科教学工作水平评估工作的发展,如何整理评估档案材料,使其能为高校评估工作提供重要的客观依据是高校必须考虑的问题。根据工作实际,对评估档案材料的原始性、针对性和规范性等问题提出一些看法。     

对英语专业八级口语口译考试评分的探讨

本文通过对英语专业八级口语口译考试的评分标准的考察，指出八级口语口译考试评分中两个突出的特点，即突出口语考试和口译考试评分“信息单元化”，从而影响口译质量评估的有效性。适当改变评分比例和口译评分标准的改进将有助于改善测评效果。     

On the concept of point value in the infinite-dimensional realization theory

In this article, we study the effect of the chosen representation of a point value (and point evaluation) on the class of periodic signals realizable using a certain type of infinite-dimensional linear system. By suitably representing the point evaluation at the origin in a Hilbert space, we are able to give a complete characterization of its extensions. These extensions involve a new concept called δ-sequence, the use of which as an observation operator of an infinite-dimensional linear system is studied in this article. In particular, we consider their use in the realization of periodic signals. We also investigate how the use of δ-sequences affects the convergence properties of such realizations; we consider the rate and character of convergence and the removal of the Gibbs phenomenon. As still a further demonstration of the significance of the chosen concept of a point value, we discuss the use of distributional point values in the realization of periodic distributions. The possible applications of this work lie in regulator problems of infinite-dimensional control theory, as is indicated by the well-known internal model principle.     

Applications of electronic speckle interferometry (ESI) techniques for spacecraft structural components

Laser-based electronic speckle interferometry (ESI) techniques, viz., electronic speckle pattern interferometry (ESPI) and electronic speckle shearographic interferometry (ESSI) are used for testing of spacecraft structural components. The combined ESPI and ESSI system developed in house was successfully used for the non-destructive evaluation (NDE) of honeycomb sandwich panels and propellant tanks of Indian Space Research Organization (ISRO). Debonds between face sheet and the honeycomb core were identified using (i) thermal and (ii) dual vacuum stressing methods. On-line NDE of the propellant tanks under internal pressure loading for identification of the minute cracks and thickness reduction areas were successfully implemented by ESI.     

人类从“自然之子”到“自然主人”的嬗变

指出了人类中心主义是生态危机的"罪恶之源",探讨了建立生态文明的必然性。