摘要:

Magnetic surface levels represent a new fundamental quantum phenomenon. Its essence is that in the surface layer of a metal placed in a weak magnetic field a system of energy levels arises for electrons moving along shallow arcs whose ends rest upon the surface of the metal. This phenomenon is due to the specular reflection of electrons at the metal surface, which gives rise to a quantized periodic motion of electrons along these ‘skipping’ trajectories. The spectrum of the system of magnetic surface levels manifests itself as an oscillatory dependence of the surface-impedance on the weak magnetic field. The impedance oscillations are due to resonant absorption of microwave radiation in electron transitions between the levels.

ISSN:0010-7514    

DOI:10.1080/00107516908204799

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

In 1903 F. Heusler reported that it was possible to make ferromagnetic alloys from non-ferromagnetic constituents copper-manganese bronze and group B elements such as aluminium and tin. Further investigations showed that the magnetic properties of these alloys are related to their chemical, L21, structure, and to the ordering of the manganese atoms on an f.c.c. sublattice.

ISSN:0010-7514    

DOI:10.1080/00107516908204800

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Some recent developments are presented which relate to the thermal conductivity of metals and its measurement. These include the influence of sample size on the electronic thermal conductivity of very pure metals, the thermal conductivity minimum of aluminium and a few other metals at sub-normal temperatures, the high-temperature thermal conductivity and increasing Lorenz function of platinum, with particular reference to the experiments of Flynn and O'Hagan (1967), the thermal conductivity of molten metals and the recently reported Lorenz functions decreasing with increase in temperature to well below the theoretical value, and the encouraging results of an investigation in progress at the Thermophysical Properties Research Center (TPRC) on direct electrical heating methods for the measurement of metallic thermal conductivities to high temperatures. Modern computer techniques avoid the restrictions and approximations introduced in the many existing methods and allow thermal conductivity to be accurately evaluated from the observed temperature profile. This method has the additional advantage that many other properties can be obtained to high temperatures for the same sample and experimental conditions. The account shows that despite the amount of effort already devoted to thermal conductivity determinations, this still remains a most rewarding field requiring further accurate measurements.

ISSN:0010-7514    

DOI:10.1080/00107516908204801

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

This paper begins with a general discussion of wave propagation in a fluid followed by an account of the accompanying attenuation and relaxation effects. The attenuation and relaxation effects due to viscosity, heat conduction and molecular processes are then discussed in some detail. Next there is a description of the various experimental techniques followed by an account of ultrasonic cavitation and a brief summary of other work.

ISSN:0010-7514    

DOI:10.1080/00107516908204802

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107516908204803

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Optical Physics. By S. G. Lipson and H. Lipson. (Cambridge University Press, 1969.) [Pp. xiii + 494.] 75s. Scope: Textbook. Level: Postgraduate; undergraduate.

ISSN:0010-7514    

DOI:10.1080/00107516908204804

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107516908204805

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor