Useful representations of series solutions for transport problems

Simple techniques are presented for rearrangement of an infinite series in a systematic way such that the convergence of the resulting expression is accelerated. These procedures also allow calculation of required boundary derivatives. Several examples of conduction and diffusion-reaction problems illustrate the methods.     

Further development of the uniqueness criteria of the steady state via the contraction mapping principle

Uniqueness criteria of the steady state in porous catalysts are derived by using the contraction mapping principle with different norms. Among the norms considered, the one involving the gradient of the steady state yields the strongest result. The criteria developed in the present study bear some resemblance to those developed by other methods     

Supercritical fluid extraction of alkaloids from Ilex paraguariensis St. Hil.

In this work a study about extracts obtained from Ilex paraguariensis St. Hil. leaves with supercritical CO₂ was carried out. Experiments were performed in a pilot-scale extractor with capacity of 1 L at pressure of 120, 150, 170 and 200 bar for four temperature conditions, 313.15, 323.15, 333.15 and 343.15 K. The experimental data were fitted using a mathematical model characterized by the existence of two distinct periods of extraction. Numerical results for the adjusted parameters correlated very well the supercritical extraction experimental data. The confidence of results obtained from mathematical model and experiments was assured through the chi-square test.     

超深井用160钢级超高强度高韧性套管的研制及组织表征

根据超深井开发要求对超高强度高韧性套管的合金化技术和制造工艺进行研究,开发出具有优异韧性和抗延迟断裂性能的BG160V超高强度高韧性套管,并分析了该BG160V套管在不同服役温度下的强韧性以及微观组织。工业性试制的性能检测结果表明：该套管的屈服强度达到1 100 MPa以上,0℃横向夏比冲击功超过名义屈服强度的10%,满足超深井油气资源开发对套管性能的要求;管体晶粒度达到11级,平均有效晶粒尺寸2.45 μm,细小的晶粒是材料具有良好韧性和抗延迟断裂性能的主要保证。     

St15钢板冲裂成因分析

在利用St15钢板生产表壳过程中有少部分原料被冲裂。采用日本扫描电子显微镜、英国牛津公司的能谱仪和EBSD、光学显微镜、拉力实验机检测结果表明,组织不均匀、{111}织构较漫散是冲裂的主要成因。     

俄罗斯圣彼得堡防潮工程建设的若干历史经验

本文系统介绍了俄罗斯圣彼得堡防潮工程规划的发展过程、工程的布置、组成以及工程的设计和当前施工的进展情况.圣彼得堡防潮工程是圣彼得堡城市建设的重要保障,在各个历史时期均得到了俄罗斯各级政府的高度重视.工程的规划、设计和施工建设过程反映了俄罗斯人对防潮管理、人水和谐相处和工程建设中对环境保护认识的发展过程.对圣彼得堡防潮工程建设经验的分析、总结,将对我国水利工作者和位于河口地区的城市防潮和防洪建设与管理起到积极的借鉴作用.     

利用卫星遥感对石家庄市西部山区特大型滑坡的初步研究

在多波段计算机处理卫星图像（Ｌａｎｄｓａｔ－５ＴＭ）中发现了特大型滑坡影像,经政府主管部门组织专家实地踏勘,得以确认。介绍了利用遥感技术结合实地考察对滑坡的发育条件、特征、成因以及稳定性进行的初步研究,并指出了该滑坡的研究意义及进一步工作方向     

Walter Pichler

Throughout his lifetime, the Austrian-born artist, maker and recluse Walter Pichler has defied an easy understanding of his work or its purpose. ‘Coming into contact with any product [of Pichler's],’ writes critic David Dunster , ‘elicits for me the sensation of a chilling proximity to the inevitable.’ Pichler, the practitioner of personal obsessions, ‘created a commentary that is far from private but retains the nature of an archetypal investigation’. In a rare look at his work, Dunster here offers us an eloquent personal insight that stirs a potent array of emotion. Copyright © 2005 John Wiley & Sons, Ltd.