摘要:

The article reviews the considerable progress that has been made recently in the experimental determination of theelectronic structureof metals and in particular the determination ofFermi surfacesand neighbouring surfaces of constant energy. In Part I the concept of electronic structure is briefly explained and this is followed by a simple analysis of the dynamics of electron motion in a magnetic field. The geometry of the orbit carried out by an electron in real space is related to the geometry of surfaces of constant energies in k-space and it is shown how the dimensions of orbits may be inferred from size-effect and ultrasonic experiments if perfect enough samples are available. Finally the frequency of rotation of the electrons in a magnetic field is related to a differential property of the constant energy surfaces and it is shown how this frequency can be measured in experiments oncyclotron resonance.

ISSN:0010-7514    

DOI:10.1080/00107517208205687

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

High-speed rotation provides many facilities which are unattainable by any other process. Very high linear velocities and also exceptionally high force fields can be obtained in the laboratory. The gyroscope can give a reference platform which is stable even within a violently unstable environment. The basic problems are outlined and some of the solutions are treated in detail. This review article deals mainly with angular velocities in the range 2000 rad s−lto 63 000 rad s−l.

ISSN:0010-7514    

DOI:10.1080/00107517208205688

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Three further types of collision between atomic systems in which no change of internal energy takes place are considered. These are collisions in which transfer of excitation occurs between two similar atoms, spin exchange collisions, and collisions in which the direction but not the magnitude of the orbital angular momentum of an excited atom is changed on impact. An account is given of the theory of these processes in relation to that for other processes, elastic scattering and symmetrical charge exchange, discussed in the earlier articles, in which no change of internal energy occurs. Methods for measuring the relevant cross sections are described. These make use of optical pumping and nuclear magnetic resonance techniques. Comparison is made between observed and calculated cross sections.

ISSN:0010-7514    

DOI:10.1080/00107517208205689

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107517208205690

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107517208205691

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Production, Pollution, Protection(Wykeham Science Series No. 19). By W. B. Yapp. (Wykeham Publications (London) Ltd., 1972.) [Pp. x + 184.] Cloth £2.75; paper £2.00. Saope: Survey; Level: General reader.

ISSN:0010-7514    

DOI:10.1080/00107517208205692

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor