摘要:

Soil has its origin in physical processes of comminution and abrasion of rock masses and in chemical processes of solution and recrystallization of rock minerals. After formation it is transported and distributed by a variety of agencies before subaerial or subaqueous deposition. Generally, soils experience a number of cycles of sedimentation, uplift, erosion and redeposition. Their mechanical behaviour under the stresses imposed by engineering structures varies with the type of soil. Both the deformation and failure of soils are of interest in the design of structures and these properties must be studied by special laboratory tests. The solution of a soil engineering problem therefore involves a field investigation and sampling programme to define the boundaries of the soil involved, laboratory testing of the soil, and analytical or computer calculations to determine the displacements and stresses which will occur in the soil and structure. Problems of particular interest include slope failures, the design of earth dams, retaining walls and piled structures, the displacement and failure of soil under buildings and the determination of soil properties on the surface of the moon and other planets.

ISSN:0010-7514    

DOI:10.1080/00107516908204404

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Generally substances are more stable in a crystalline than in a glassy state. Therefore, to form a glass, crystallization must be bypassed. Under certain conditions, the melts of many substances can be cooled to the glass state. Whether or not the melt of a given material forms a glass is determined principally by a set of factors which can be specified to some extent in the laboratory, namely, the cooling rate, -T, the liquid volume,v], and the seed density,psand upon a set of materials constants: the reduced crystal–liquid interfacial tension, α the fraction,f, of acceptor sites in the crystal surface, and the reduced glass temperature,Trg. The glass-forming tendency will be greater the larger are -TandTrgand the smaller arev].ps, andf. The number and variety of substances which have been prepared in a glassy or ‘amorphous solid’ form have been greatly increased with techniques in which the material is condensed from solution on to a surface held well below its glass temperature. There are at least some glass formers in every category of material, according to bond type, i.e. covalent, ionic, metallic, van der Waals or hydrogen. However, it is not established whether or not every substance can be put into a glass form.

ISSN:0010-7514    

DOI:10.1080/00107516908204405

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Eyring's thermodynamic treatment of diffusive and viscous flow in liquids is reviewed here in simple statistical terms. The requirement for dynamic equilibrium between the bulk and surface layers of a liquid is shown to lead to a surface tension, while capillary rise follows on demanding equality of diffusion rates along the wall, The simple models employed here predict quantities which are in order-of-magnitude agreement with experiment.

ISSN:0010-7514    

DOI:10.1080/00107516908204406

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A novel method for doping semiconductors is ion implantation where impurities are injected in the form of high-energy ions. The range of these ions is well defined and is a function of ion energy and mass, the nature of the crystal and its orientation to the beam. In addition t o its application to semiconductor device manufacture, ion implantation involves a good deal of interesting physics over a wide field, and in order to include the important aspects the article has been divided into two parts.

ISSN:0010-7514    

DOI:10.1080/00107516908204407

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Applied Group Theory. By A. P. Cracknell. (Pergamon, 1968.) [Pp. xi+417.] 45s. hard; 35s. flexi.

ISSN:0010-7514    

DOI:10.1080/00107516908204408

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107516908204409

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor