Estimation of the modulus of the vector of displacements in the process of simultaneous formation of cracks in the composites

We propose a computational model of the emission of acoustic signals accompanying the fracture processes in composite materials caused by the formation of several cracks regarded as separate events of macrocrack initiation. We perform the numerical analysis of the components of the vector of displacements for some typical cases of the relative location of two simultaneously formed penny-shaped cracks. The analysis of the modulus of the vector of displacements reveals the direct proportionality between its maximum values and the total area of the formed defects that, as well as the inverse proportionality between the same quantities and the period of relaxation of stresses on the cracks lips.     

Difference in the Definitions of Coherence in the Space-time Domain and in the Space-frequency Domain

Abstract

Coherence in the space-time domain and in the space-frequency domain are compared and found to be non-equivalent. Coherence in the space-time domain is sufficient for coherence in the space-frequency domain. Coherence in the space-frequency domain is not sufficient for coherence in the space-time domain. The source spectrum as well as coherence in the space-frequency domain effect coherence in the space-time domain. The coherence in the radiation field from two very different localized sources is studied. It is found that the fields are coherent throughout the far field region only if the sources are monochromatic.     

立体视差法中距离分辨率的理论分析

推导了立本视差法中距离分辨率，探测范围，探测距离，两ＣＣＤ摄象机的间距及ＣＣＤ本身各参数之间的关系。利用这些关系可优化化立体视差法的结构参数。     

软装饰风格的极简主义在精品酒店中的研究应用

一、极简主义的概念和内涵 极简主义(Minimalism)[1],并不是现今所称的简约主义,而是第二次世界大战之后60年代所兴起的一个艺术流派,作为对抽象表现主义的反动而走向极致,开放作品自身在艺术概念上的意像空间,让观者自主参与对作品的建构,最终成为作品在不特定限制下的作者.     

工科院校实践教学改革探索

文章分析了实践教学过程中几个重要环节中存在的问题，探讨了工科院校实践教学改革之路。     

Measurement of the dose in quartz in the presence of feldspar contamination

To allow the determination of the dose in quartz in the presence of feldspar contamination, the quartz-to-feldspar optically stimulated luminescence (OSL) ratio needs to be maximised. Experiments were carried out to find the optimum procedure to bleach the feldspar by exposure to infrared light, without seriously affecting the quartz OSL signal. A single-aliquot regenerative-dose protocol is proposed which, in our samples, allows accurate measurement of the dose in quartz in the presence of feldspar contamination. The protocol also has potential use for quartz dose determination in mixed-mineral samples.     

Elements in the determination of instability in the intensity of laser radiation

The article presents a formula for estimating the component of uncertainty in the measurement of the relative statistical fluctuation of the power of laser radiation caused by a finite number of measurements of power on the basis of which instability is determined. The influence of drift on the measured radiation power is established and a formula for adding the drift and fluctuation components of the relative statistical fluctuation is checked. __________ Translated from Izmeritel’naya Tekhnika, No. 11, pp. 28–32, November, 2006     

小型硐室爆破在城郊石料开采中的应用

比较详细地介绍了小型硐室爆破在武汉市城郊长岭山石料场石料开采中应用概况。重点介绍了药室的布置、爆破参数的选择、起爆网路设计和爆破安全校核等技术问题。此次的工程实践经验对类似石料场的石料开采有一定的借鉴价值。