A new surface characterization technique: RIMAPS (Rotated Image with Maximum Average Power Spectrum)

This work introduces a new imaging technique, Rotated Image with Maximum Average Power Spectrum (RIMAPS), for use in determining orientation and characteristics of surface topography. It consists of computing the maximum value of the averaged power spectrum, given by one step of the two‐dimensional Fourier transform, for each angle of rotation of a digitized image. The basic measurement science of this technique is described and different cases are studied. The characterization of simple geometrical figures explains the meaning of peaks and their angular positions given by RIMAPS analysis. A known surface pattern made on a sample of pure copper, mechanically ground, is used to study reproducibility, dependence on image quality and topography scale relative to pixel size and magnification. Samples of pure zinc, mechanically ground and chemically etched, were used to show the main features of RIMAPS analysis when characterizing a more complicated pattern on a real surface. All the studies performed under different conditions for observation and acquisition of images give strong evidence of the stability and robustness of RIMAPS as a technique for the characterization of topography.     

关于瞬态应力强度因子和裂纹扩展加速度之间的关系探讨

将动态焦散线法与高速摄影技术相结合,本文记录了高分子材料悬臂梁内裂纹扩展加速、减速过程。一方面,利用动态焦散线可确定扩展裂尖的瞬态应力强度因子;另一方面,利用最小二乘法将裂纹扩展的水平、垂直位移分量拟合成时间(t)的四次多项式,描述了裂纹扩展方向、裂纹扩展加速度以及裂纹扩展加速度与动态应力强度因子的关系。结果表明:裂纹扩展加速度与动态应力强度因子之间存在一定的依赖关系;利用最小二乘法将裂纹扩展的水平、垂直分量拟合成时间(t)的四次多项式,可以对裂纹的扩展方向、加速度进行定量分析。     

Pit to crack transition in stress corrosion cracking of a steam turbine disc steel

Long term exposure tests have been carried out on a 3 NiCrMoV steam turbine disc steel in the form of cylindrical tensile test specimens self-loaded to 90% of σ_0.2 and exposed to three environmental conditions, viz. deaerated pure water, aerated pure water, and aerated water containing 1.5 ppm of chloride ion. Pitting occurred in all environments but the density and depth of pits in the chloride-containing medium was markedly greater. No cracking was observed in deaerated pure water but cracks initiated in aerated water between 13 and 19 months and in less than 7 months in aerated 1.5 ppm Cl⁻ solution. The probability of a crack initiating from a pit of specific depth in aerated solution could be described well by a Weibull function. Profiling of pits and cracks in the disc steel tested in aerated 1.5 ppm Cl⁻ solution showed that there while there were many cracks with a depth greater than that of the corresponding pit the depth of some cracks was smaller than that of the corresponding pit, suggesting that cracks do not necessarily initiate from the bottom of the pits. The growth rate of short cracks emerging from pits appeared greater than that of long cracks in fracture mechanics specimens.     

从限额设计谈投资控制

文章根据设计阶段投资控制的现状及存在问题,提出只有在设计行业全面推行限额设计,深化设计阶段的投资控制工作,才能从根本上体现全过程投资控制的理念,提高投资控制效果,节约建设工程总投资。     

转向柱管承载能力的试验研究

在分析转向柱管花键部位应力集中情况的基础上,通过对某厂生产的转向柱管扭转破坏的试验研究,得到如下结论:①转向柱管的承载能力与其外花键齿与方向盘中心内花键齿之间的非接触区长度有关,以花键端部过渡圆弧的直径大小为宜;②安装方向盘总成时所施加在安装螺母上的拧紧力矩在70N.m左右时,转向柱管的承载能力最大。     

Direct Methods Optimised for Solving Crystal Structure by Powder Diffraction Data: Limits,Strategies, and Prospects

The ab-initio crystal structure solution by powder diffraction data requires great efforts because of the collapse of the experimental information onto the one dimensional 2θ axis of the pattern. Different strategies will be described aiming at improving the process of extraction of the integrated intensities from the experimental pattern in order to make more straightforward the structure solution process by direct methods. Particular attention will be devoted to the EXPO program. Some of its performance will be analysed and results will be shown.     

万家寨引黄南干线二级泵站出水压力平洞混凝土衬砌裂缝成因与处理

分析引黄南干二级泵站出水压力平洞混凝土村砌裂缝成因以及处理办法     

多孔粒状铵油炸药在边坡预裂爆破中的应用

通过工程实践，介绍了利用多孔粒状铵油炸药进行边坡预裂爆破的设计原理及施工工艺。该技术能确保预裂爆破质量。简化施工工序，大幅度降低爆破成本。技术经济指标优越。     

The Importance of Shared Environment in Infant-Father Attachment: A Behavioral Genetic Study of the Attachment Q-Sort.

In this first behavior genetic study on infant-father attachment, we estimated genetic and environmental influences on infant-father attachment behaviors and on temperamental dependency, both assessed with the Attachment Q-Sort (AQS; B. E.Vaughn & E. Waters, 1990; E. Waters, 1995). Mothers of mono- and dizygotic twins (N = 56 pairs) sorted the AQS with a focus on the infant's behaviors in the presence of the father. Genetic modeling showed that attachment was largely explained by shared environmental (59%) and unique environmental (41%) factors. For dependency, genetic factors explained 66% of the variance, and unique environmental factors including measurement error explained 34%. Attachment to father appears to be, to a significant degree, a function of the environment that twins share. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

碳纤维增强混凝土构件正截面计算的双界限系数法

以材料的力学性能分析为基础，利用双界限系数将碳纤维增强混凝土受弯构件划分成三种正截面的破坏形态，对每一种破坏形态，建立了单、双筋矩形截面极限承载力的计算式，使碳纤维增强混凝土构件正截面计算与现行的规范相一致。