中国照相材料市场的百年回顾

经过１５０多年的发展,中国照相市场经历了从无到有,从黑白照相到彩色照相,从富人的奢侈品到老百姓的消费品,从传统银盐照相到电子数字成像的巨大变化。随着摄影技术和照相工业的飞速发展,中国照相市场即将进入一个新的发展时期。 “摄影”作为一门在西方兴起的新型实用技     

热显影卤化银彩色照相材料

概述了热显影卤化银彩色照相材料的发展过程，介绍了这种照相材料的构成、成像原理以及所用主要有机材料的结构类型．     

数码照相用全彩直接感热记录材料

1 前言 直接感热记录系统(TA方式)于1994年发售，它是全彩打印输出数字影像的方式之一。经过改良影像的坚牢性、非影像的白度、光泽度等各方面的性能，于2002年5月发表了新型数码照片打印机“Printpix CX-400”专用的高画质、高保存性的TA纸。TA方式用简单的打印机就能得到直接感热记录很难实现的全彩影像(TA纸)。     

非银盐感光材料发展近况

本文叙述了近年来非银盐感光材料,例如抗蚀剂,聚酰亚胺、光致变色、液晶、高分子等材料的研究、应用和发展状况。     

Review Stability of nanostructured materials

The different aspects of nanostructured material (NM) stability such as thermal and chemical stability as well as NM behavior under deformation and radiation are characterized and analyzed in detail. Grain growth, phase transitions (including spinodal decomposition), homogenization diffusion processes, relaxation of residual stresses, and behavior of grain boundary and triple junction segregations are discussed in context of the change of nanostructure and properties. Special interest is given to the availability of NMs with ultra-fine grain size and their behavior during annealing as soon as to the possibility of development of nanostructures with high thermal stability. Some unsolved problems are emphasized.     

软填料生物接触氧化法处理感光污水

软填料在射流曝气池内,采用悬挂安装工艺处理感光污水,在此特定条件下,软填料与新安装的蜂窝填料有同样效能,其优点大于蜂窝填料,克服了蜂窝填料堵塞的最大缺点。     

Stability of surface integral equation for left-handed materials

In recent years, left-handed materials (LHMS) have been a hot and debated research topic. Electromagnetic simulation is usually performed for prediction as well as for design. The stability of the surface integral equation method through an insightful and rigorous procedure is analysed. The conclusion is that the PMCHWT formulation at perfectly matched LHM-RHM interface has stability problem, which comes from the plasmon resonance condition. Adding a small amount of loss can greatly improve the condition number of the matrix. Physical and consistent numerical results are shown followed by a brief conclusion     

Stability of cracks in elastic and in elastic plastic materials

The theory of the stability of cracks in an elastic material is summarized. The theory is extended to the case of a non-work-hardening elastic plastic material and is applied to a number of crack geometries and loadings.

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Zusammenfassung Die Theorie der Risstabilitat irn elastischen Material wird zusammengefasst. Anschliessend wird these Theorie ausgedehnt auf durch Behandlung nicht härtbare elastisch-plastische Materialien Bowie auf verschiedenartige Rissformen and Belastungen angewandt.

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Résumé On a resumé la théorie de la stabilité des fissures dans un material elastíque. Cette théorie est étendue au cas de materiaux elasto-plastique non sujets au durcissement par écrouissage, est appliquée a plusieurs types de géometries de fissures et de conditions de sollicitations.

     

Stability of dynamically propagating cracks in brittle materials

Summary Dynamic crack propagation and bifurcation phenomena are investigated analytically by utilizing the strain energy density fracture criterion in the framework of catastrophe theory. The effect of biaxial stress, loading imperfections (mixed-mode loading), Poisson's ratio, state of stress as well as crack tip propagation speed on the crack path directional stability is analyzed. Special crack path stability charts for (un)stably propagating cracks are obtained, and their connection with the experimentally recorded crack tip stress field is addressed. It is shown that a slight change of the normal stress acting parallel to a crack at its tip (crack-parallel stress) may be able to affect the crack surface roughening and/or branching velocity considerably. It is also indicated that under small tensile crack-parallel stress, the crack propagation is stable only when the crack propagation speed is less than about 30% of the relevant shear wave speed. The crack becomes unstable, and its surfaces roughen severely at a higher speed, and the crack bifurcates at the highest propagation speed, some 45% of the shear wave speed. It is suggested that superimposing mode-II (shear) loading will enhance the dynamic crack path stability while increasing crack propagation speed will reduce the stability of crack propagation. It is expected that under compressive crack-parallel stress no crack surface roughening will occur before the crack stably bifurcates.