Vol. 22, No. 3 (1966)
1966-02-05
CONTENT
1966, 22 (3): 257-269.
doi: 10.7498/aps.22.257
Abstract +
Under the action of the illuminating electron beam in an electron microscope, dislocations in Al-Mg alloys start to move during examination. It was found that screw dislocations move and change easily their moving direction producing many double cross-slip traces, and that slip and cross-slip first occur on those {111} planes lying close to the position at 45°with the foil surface. The cross-slip direction or the Burgers vector of the screw dislocation is the α/2 making an angle of 60-80° with the foilnormal. These observations are in good agreement with the fact that the stress is assumed to be tangential to the foil surface during bending caused by heating.The moving dislocation may through its stress field induce the movement of other dislocations lying close to its path, and on the other hand, may itself be stopped or forced to change its moving direction by the repulsive force of other dislocations.
1966, 22 (3): 270-280.
doi: 10.7498/aps.22.270
Abstract +
Variations of internal friction in the course of strain-aging at room temperature of slightly cold-worked Al-0.1% Mg alloy were measured with a torsion pendulum and an internal friction peak (versus aging time) exhibiting anomalous amplitute effect was observed. When the internal friction of a fully aged specimen was measured with the temperature going up and down, internal friction peaks (versus temperature) exhibiting anomalous amplitude effect were also observed in the temperature range of 30-55℃. These anomalous effects were not observed in specimens of high purity aluminum or fully-annealed Al-0.1% Mg alloy.The fact that these anomalous internal friction phenomena previously observed in Al-0.5% Cu alloy can also be observed in Al-0.1% Mg alloy excludes any possibility of explaining these anomalous internal friction phenomena in terms of a precipitation process which cannot occur in Al-0.1% Mg alloy in the temperature range of the present measurements.In order to explain the characteristics of the anomalous internal friction phenomena observed in the aluminum-magnesium alloy, two different types of dislocation atmospheres were assumed to be able to exist in an aluminum-magnesium alloy: One type is concerned with the segregation of "magnesium atom-vacancy" pairs to a dislocation, which can happen during the course of strain-aging; another type is concerned with the segregation of magnesium atoms to a dislocation, and these results when the cold-worked specimen was heated to a temperature around 100℃, at which temperature magnesium atoms were freed from the vacancies and so are able to form an atmosphere alone with a dislocation when the temperature is lowered. The pinning of a dislocation by an atmosphere of the former type is stronger than that of the latter, so that the amplitude internal friction peak associated with the former appeared at a higher amplitude level.
1966, 22 (3): 281-293.
doi: 10.7498/aps.22.281
Abstract +
Assuming the metals to be an isotropic, unbounded and homogenous elastic continuum, the tetrahedral and octahedral position energy of interstials (C,N,O and H) in b.c.c. metals (Fe, W, Mo, Ta and Nb) are evaluated by means of the concept of elastic dipole. The results show that all of them occupy the octahetral positions except H, which in W, Mo, Ta and Nb favours the tetrahedral position, and the critical radius of interstials at which the favoured position is exchanged have been given also. The activation energies of interstials moving between octahedral positions are calculated. The results are compared favourably with previous experiments.
1966, 22 (3): 304-309.
doi: 10.7498/aps.22.304
Abstract +
The influence of transverse magnetic field on surface a.c. field-effect in germanium has been studied, and a different interpretation from other inverstigators is proposed. According to our experimental results, it may be considered that the influence of magnetic field on surface field-effect is predominantly referred to the additional change in conductance of sample caused by the "magnetic-concentration effect" rather than the change in surface barrier height caused by the Hall e.m.f., and we also suggest the possibility of using this experiment to determine the dependence of the surface recombination velocity on the surface barrier.
1966, 22 (3): 310-317.
doi: 10.7498/aps.22.310
Abstract +
Using the zone-levelling technique, homogeneous alloys of the AlSb-GaSb-InSb system were obtained. The homogenized specimens were studied by means of the X-ray (Debye-Scherrer) method and differential thermal analysis. These results showed that in the above mentioned system solid solutions occur in all range of compositions. The liquidus projection of the AlSb-GaSb-InSb system and the relation between composition and lattice parameter of the AlSb GaSb-InSb section were established. Stabilities of alloys with different compositions in air were also compared.
1966, 22 (3): 318-324.
doi: 10.7498/aps.22.318
Abstract +
This paper analyzes, with single energy-level recombination-centre model, the phase-shift lifetime of excess carriers in semiconductors under sinusoidal injection. Hence are obtained the difference and sameness between phase-shift lifetime and static state lifetime as well as transient state lifetime:1. The phase-shift lifetime in relation with the injection frequency decreases as the frequency increases.2. Under low frequency injection, the phase-shift lifetimes of electrons and holes are the same and equal to transient state lifetime.The conditions of low frequency injection are discussed in this paper.
1966, 22 (3): 325-333.
doi: 10.7498/aps.22.325
Abstract +
The relation between the subtracted dispersion relations for the low energy pion-nucleon scattering and the usual Lagrangian formulation under the renormalization treatment is discussed in the present paper. It is shown that the subtraction actually represents the renormalization of the interaction constants. Using the subtracted dispersion relations we have treated the problem of the S-wave pion nucleon scattering. Our result shows that the interaction between the pion and the nucleon should be of the pseudo-vector type rather than the pseudo-scalar type.
1966, 22 (3): 334-340.
doi: 10.7498/aps.22.334
Abstract +
In this paper, we discuss the lepton structure and the (μ-e mass-difference on the basis of the "muonic charge" model. Some general theorems concerning the lepton structure are demonstrated. For example, it is shown that the form factors of "muonic charge" current and of electric current of charged lepton having anomalous interaction are equal. As a result, this lepton would posses a "muonic moment". It is shown that the anomalous interaction self-energy corresponding to "muonic-charge-muonic moment" interaction is the dominated term and the μ-e mass difference is consistent with the known experimental data of the electromagnatic structure of the eletron.
1966, 22 (3): 341-359.
doi: 10.7498/aps.22.341
Abstract +
In this work we report experimental studies of the critical magnetic field for indium films of different thicknesses alloyed with 2 at.% and 3 at.% of tin, thus furnishing, for the first time, experimental data of Hc～d for the case of finite electronic mean free path. From these data, it is concluded that the critical magnetic field of thin films can only be discussed in the light of the non-local, nonlinear theories, and that in the thin film limit, Hc∝d-3/2 for both pure and alloyed films. The local theories of london and of Гинзбург-Ландау, and the non-local, linear theory of Ittner, are inapplicable. The erroneous conclusion of Hc∝d-1 made by certain outhors, is due to their incorrect analyses of their experimental data.
1966, 22 (3): 360-370.
doi: 10.7498/aps.22.360
Abstract +
In ferromagnets and antiferromagnets, the coupling between phonons and magnons cannot be overlooked, because of the exchange interaction changing with the distance between the magnetic ions. In this article, the possible effect of this coupling on the infrared absorption in magnetic insulators has been considered. The transition involved consists of the excitation of an optical phonon by the interaction with radiation field and simultaneously that of two magnons and a phonon due to the perturbation of the phonon-magnon coupling. It produces an absorption band with frequencies higher than the edge of the lattice absorption. Since the total spin component Sz must be conserved, this effect should not be found in ferromagnetic insulators. If the Néel temperature of an antiferromagnet is high enough and the distribution of spin wave states vs. energy has a sharp maximum the predicted absorption band becomes observable. Our treatment is aimed at the 0.24 eV absorption band of NiO. Its peak energy and absorption constant are calculated. The results appear in fair agreement with the experimental findings. Finally, it is pointed out that the transition process adopted by Mizuno and Koide for explaining the same phenomenon can only offer a secondly effect in comparison with ours.
