摘要:

Self‐diffusion coefficients for both In114and Sn113as tracers have been measured in the liquid In‐Sn alloy at several concentrations. The temperature range investigated is the range 200°–600°C. The dependence of diffusiveness on temperature at constant composition can be represented by the customary Arrhenius equation for all the compositions investigated. The variation of diffusiveness with composition at constant temperature is also examined, and it gives evidence of a large difference in the behavior of the two tracers.

ISSN:0021-8979    

DOI:10.1063/1.1736048

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

An alloy of 70 mol % Bi2Te3−30 mol % Bi2Se3, or Bi2Te2.1Se0.9, is the intrinsic semiconductor of the pseudobinary system Bi2Te3&sngbnd;Bi2Se3. This V–VI alloy was doped with lead (Group IV) and iodine (Group VII) separately and together. The effects of the dopants are analogous to those produced by Group III or Group V impurities in Group IV elemental semiconductors, the lower Group impurity producing ap‐type material and the higher Group impurity ann‐type material. Plots of the Seebeck coefficient, electrical conductivity, and thermal conductivity are given as a function of impurity concentration and show that the separate effects of the impurities are countered when the impurities are in the lattice together in the same amount.Doping was also done with silver and iodine, separately and together. The results indicate that the silver is in the lattice interstitially (lead and iodine substitutionally) and that the type material produced is dependent also on how the impurity atom enters the lattice.

ISSN:0021-8979    

DOI:10.1063/1.1736049

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The theory of the direct Fourier analysis with finite sampled data is developed. Formulas for planning a measurement for a specified resolution and accuracy are obtained. A quantitative comparison with autocorrelation analysis is given. It is shown that direct Fourier analysis can be applied equally well to attain comparable resolution and accuracy with the same amount of data. The computer requirements are also comparable in both cases.

ISSN:0021-8979    

DOI:10.1063/1.1736050

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

It is shown that through the use of the infrared absorption technique to measure the added carrier density in a semiconductor bulk adjacent to a metal contact coupled with simultaneous measurement of the floating potential of the contact, a reliable determination of the semiconductor surface barrier height under the metal contact can be obtained.

ISSN:0021-8979    

DOI:10.1063/1.1736051

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Absorption of radio signals by cyclotron resonance is shown to be possible within a very narrow layer of the atmosphere (20 km thick just below 100 km). For a plane‐polarized signal only 25% of the power can be absorbed. Better results are obtained (50%) with a circularly polarized radio wave. The absorbable power is limited by the effects obtained so that an electron density of 3000 cm−3and an electron temperature of 1600°K cannot be exceeded. The reason for this is the weakness of the earth's magnetic field.

ISSN:0021-8979    

DOI:10.1063/1.1736052

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The boundary conditions for a radio signal incident normally on a layer of plasma are discussed. It is shown that 10 different modes must in general propagate in the layer, instead of the usually assumed six. The 10 modes are obtained when the Langevin form of the force is used in Boltzmann's equation.

ISSN:0021-8979    

DOI:10.1063/1.1736053

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

A method is developed whereby electrical conductivity and dielectric constant of semiconducting and dielectric materials without contacting electrodes can be measured. The principle of this method is that a specimen suspended in a rotating field with a fine fiber is rotated by the torque proportional to the electrical conductivity or the imaginary part of its complex dielectric constant, and the torque exerted on it by a linearly polarized field is proportional to the real part of its dielectric constant.An analysis of the method and some preliminary measurements of conductivity, photoconductivity, the dielectric constant of cadmium sulphate crystals and the dielectric loss of the lamella containing CdS powder are presented. The latter shows the photodielectric effect.

ISSN:0021-8979    

DOI:10.1063/1.1736054

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The nature of double cross slip of screw dislocations as induced by a locked parallel screw dislocation, that of edge dislocations as induced by a locked edge dislocation through climb, and that of the cross climb of edge dislocations as induced by another edge dislocation through slip are studied in the light of the interaction of the mutual stress fields of the dislocations. Some quantitative calculations of the multiplication of a single loop and of the growth of slip bands in LiF are given; it is found that agreement with the experimental results of Johnston and Gilman [W. G. Johnston and J. J. Gilman, J. Appl. Phys.30, 129 (1959);31, 687 (1960)] is satisfactory. A mechanism for linear hardening at low stresses is suggested.

ISSN:0021-8979    

DOI:10.1063/1.1736055

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

Measurements of conductance, lifetime, change in contact potential with light, and contact potential have been carried out on bombardment‐cleaned silicon surfaces and during the adsorption of molecular oxygen and atomic hydrogen. In the case of oxygen adsorption, the work function increased linearly with coverage. A change of 0.35 ev was obtained in going from &thgr;=0 to &thgr;=1. Very small changes in the transport properties were observed. Hydrogen atoms produced an initial decrease in work function of 0.1 ev for coverages below &thgr;=0.35. From &thgr;=0.35 to &thgr;=1.0 the work function was increased by 0.3 ev. The changes in the transport properties were substantial and indicated a downward movement of the energy bands at the surface by about 0.08 ev. In the clean condition, the valence band edge was 0.12–0.14 ev below the Fermi level at the surface compared to 0.36 ev in the interior. The effect of hydrogen adsorption is discussed in terms of the adsorption data previously obtained on this system.

ISSN:0021-8979    

DOI:10.1063/1.1736056

出版商:AIP    

年代:1961

数据来源: AIP

摘要:

The response of a thermocouple circuit functioning as a Peltier cooler to time‐varying currents was determined by assuming that the current density could be represented by the sum of a dc and a time‐varying component. The time‐varying component took the form of either an impulse applied at timet0>0, a square pulse lasting fromt0tot1, a step increase in the current at timet0, or a sinusoidal ripple superposed on the dc current. The increased current results in an initial thermal cold spike at the cold junction but the time‐average temperature difference between the junctions is reduced unless the dc current is well below the optimum value. The possibility of using such thermal spikes in a very long wavelength infrared communications system or in synchronous detection is discussed. In the case of a sinusoidal ripple the temperature difference between the junctions may either follow the fluctuations in current or may not, depending on the time constant of the couple and the frequency of the ac signal. In the latter case the only effect is a reduction in the temperature difference between junctions by the additional Joule heating due to the ac component.

ISSN:0021-8979    

DOI:10.1063/1.1736057

出版商:AIP    

年代:1961

数据来源: AIP