摘要:

The experimental work on the radioactivity decay of the neutron between 1948 and 1981 is reviewed in the light of the developments in our understanding of the beta decay process. Whereas the early work was primarily concerned with the nature of the decay the more recent experiments have concentrated on an accurate determination of the ratio of the coupling constants involved in the process. The progress has been impressive but our knowledge of the half-life is still disappointingly imprecise.

ISSN:0010-7514    

DOI:10.1080/00107518308210669

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Newton's life and work are briefly summarized and it is reasoned that we are in a better position today than a century ago for evaluating his accomplishment. ThePrincipiais then presented and discussed in some detail. Stress is laid especially on the difference between the first two books, where Newton put together into one coherent ‘general mechanics’ his own and his predecessors' discoveries, and the third, where the theorems are applied for explaining the Solar System, the motions of planets and comets, and the tides. There follows an explanation of how Newton's ideas were propagated, even though thePrincipia, unlike theOpticks, was understood by only a few scientists. Through the work of D. Bernoulli and L. Euler, especially, Newton's mechanics was transformed and expanded into an endeavour of endless application. It is shown that the theory of relativity, although marking a limit to the validity of Newton's mechanics, has made clear how much better than most of his critics Newton understood the problems behind his work.

ISSN:0010-7514    

DOI:10.1080/00107518308210670

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The dynamic electronic structure of atoms and molecules can be directly observed by means of the (e, 2e) reaction, which measures the distribution of energies and momenta of two electrons in coincidence after a knockout reaction initiated by an electron beam of known momentum incident on a molecular gas target. The molecular state for each event is identified by the electron separation energy. The recoil momentum for each event is known from the difference of measured initial and final momenta. It has been verified that values of this momentum are equal under suitable conditions to the momentum of the electron in the target immediately before knockout. Thus the spherically-averaged electron momentum distribution for each molecular orbital is measured. This is directly related to molecular orbitals calculated by the methods of quantum chemistry. Properties obtained by this method for different types of molecules are discussed.

ISSN:0010-7514    

DOI:10.1080/00107518308210671

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The neutrinos, should they possess mass, are expected to have small masses, possibly too small to be measured with present-day spectrometers. Ifat least two of the three known types of neutrino have different masses, they may transform from one type to the other and back again. Such transformations are called oscillations. Neutrino oscillations have been discussed extensively as being expected on theoretical grounds, creating new interest in the search for oscillations.

ISSN:0010-7514    

DOI:10.1080/00107518308210672

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518308210673

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518308210674

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518308210675

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518308210676

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518308210677

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Engines, Energy and Entropy: a Thermodynamics Primer. By J. B. Fenn. (W. H. Freeman, 1982.) [Pp. 293.] Board, £13.50; paper £6.95. Scope: Textbook. Level: General reader, Undergraduate, School.

ISSN:0010-7514    

DOI:10.1080/00107518308210678

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor