摘要:

The valence electronic structure of materials with crystalline order is described by the energy—momentum dispersion laws and densities of electron bands. These quantities are directly observed for the surfaces of thin (about 100 Å) solid films by electron momentum spectroscopy, based on kinematically complete observations of ionization events. The principles of the experiment and the imperfections of the probe are described and illustrated by examples. Comparison is made with other electron spectroscopies that measure subsets of the complete energy-momentum density information.

ISSN:0010-7514    

DOI:10.1080/00107519408222127

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Radioactivity in the environment includes naturally occurring as well as man-made radionuclides. Meaningful estimates of their hazard to health require much care in obtaining representative environmental samples, appropriate sample preparation as well as proper calibration of the measuring system. Any harm from the low absorbed doses of ionizing radiation typically received from environmental radioactivity would only occur after a latent period of several years. Of these, cancer induction is considered to be the most important. Risk factors have been derived by a number of internationally recognized organizations, but there are difficulties in extrapolating from observations at a high dose and dose rate and for the lifetime of exposed populations. Examples of measurement of222Ra,90Sr,125I,226Ra,129I and137Cs in the environment are given. Harmful effects from environmental radioactivity have mostly been indistinguishable above natural incidence. For health purposes there may be little need for further increases in sensitivity of detection but there is a continuing need to ensure the greatest accuracy in measurements to avoid magnifying the inevitable uncertainties in estimating radiation hazards.

ISSN:0010-7514    

DOI:10.1080/00107519408222128

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A review ofThe End of Physics: The Myth of a Unfiled Theoryby David Lindley (Basic Books, 1993.), £15.99, US$25OO(hbk), pp. 275. ISBN 0 465 01548 4. Scope: physics-philosophy. Level: General reader.

ISSN:0010-7514    

DOI:10.1080/00107519408222129

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A review ofAn Introduction to the Liquid State, Second edition. By P. A. Egelstaff. (Oxford University Press, 1992) [pp. ix + 390] £55.00 (hbk). ISBN 0 19 8510128. Scope: Monograph. Level: Post-graduate.

ISSN:0010-7514    

DOI:10.1080/00107519408222130

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A review ofPhysics and Probability, Essays in Honor of Edwin T. Jaynes. Edited by W. T. Grandy Jr and P. W. Milonni (Cambridge University Press), (1993). [Pp. x + 284] £35.00, US$49.95 (hbk) ISBN 0 521 43471-8. Scope: Essays. Level: Postgraduate.

ISSN:0010-7514    

DOI:10.1080/00107519408222131

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Algebraic Methods in Molecular & Nuclear Structure PhysicsBy A. Frank and P. van Isacker 1994, £54.00 (hbk) pp. xii + 488. Wiley, ISBN 0 47152640 1. Scope: monograph. Level: specialist.

ISSN:0010-7514    

DOI:10.1080/00107519408222132

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107519408222133

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor