摘要:

Accelerator based methods using ion beams form a valuable set of techniques for characterising, modifying and developing materials which complement and extend the technological uses of other energy beam methods involving lasers, synchrotron sources, neutrons and electron beams. Such methods, many first developed and increasingly used in the nuclear industry over the last decade, are currently being rapidly exploited in other high technology areas in the chemical, micro-electronics and biotechnology industries. These methods are based on the inherent atomic and nuclear properties of fast ion beams in materials; ions slow down and stop by atomic collision within well-defined depths which depend on the energy and species. By the suitable choice of these parameters, the depth of interaction can be precisely controlled over a very wide range from nanometres to centimetres, which covers the range of depths which exhibit material surface properties such as corrosion, oxidation, wear and catalysis. Nuclear interactions during the slowing down process produce primary and secondary radiations with predictable strength so that concentrations of the element isotopes can be determined. Microstructural and microanalytical information can often be obtained non-destructively and sometimes on-line to the working environment.

ISSN:0010-7514    

DOI:10.1080/00107518508210990

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

High-pressure nozzle sources yielding neutral particle beams with good monochromacy and high intensity have been combined in the last few years with ultra-high vacuum techniques to allow for atomic beam scattering experiments from solid surfaces which meet the purity requirements of modern surface science. Thus, experimental investigations even of very reactive surfaces have become possible. Beam techniques are presently being used in many branches of surface physics and chemistry, such as studies of the particle-surface physisorption potential, of surface structure, of surface phonons, of surface migration and diffusion, of the energy exchange upon collision of heavy particles and molecules with surfaces, and of substrate-mediated chemical reactions.

ISSN:0010-7514    

DOI:10.1080/00107518508210991

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper offers (in two parts) a broad overview of recent developments concerning the use of curved space concepts in amorphous structures. Keeping particularly in mind nonspecialist readers, expository background material is included, wherever appropriate. Part I deals essentially with geometrical modelling, and starts with a brief recapitualtion of the famous model-building exercise due to Bernal. We then discuss the Kleman-Sadoc prescription for realizing amorphous structures as mappings of spherical polytopes (the four-dimensional analogue of spherical polyhedra) onto Euclidean space. Such an approach has not only provided a fast and convenient algorithm, but more importantly, has focused attention on the line defects (disclinations) in amorphous structures. As a result, one is now able to relate these disclinations to the Frank-Kasper lines present in complex alloy structures. In turn, this has led to a qualitative scenario for the transformation of the liquid during a cool-down, into the crystalline or the amorphous state. Part II deals with attempts to provide a quantitative structure to this scenario via gauge theories.

ISSN:0010-7514    

DOI:10.1080/00107518508210992

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518508210993

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Spin Excitations in Nuclei.Edited by F. Petrovich, G. E. Brown, G. T. Garvey, C. D. Goodman, R. A. Lindren and W. G. Love. (New York: Plenum Publishing Corporation, 1984.) [Pp. xii+658.] $95.00. Scope: Conference Proceedings. Level: Specialist.

ISSN:0010-7514    

DOI:10.1080/00107518508210994

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518508210995

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor