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Vol. 21, No. 9 (1965)

1965-05-05
CONTENT
WIDTH AND SHIFT OF THE Mg II 4481? LINE FROM A PLASMA SOURCE
CHEN LIN-TANG, CHOW TUNG-CHING
1965, 125 (9): 1591-1605. doi: 10.7498/aps.21.1591
Abstract +
Line profiles and shifts of the Mg II 4481? line (32D-42F) were measured for a range of electron number densities from 7×1016 to 3.1×1017 clectrons/c.c. An oscillatory condenser discharge was used as a spectroscopic source. Electron-number densities were determined from measured widths of the Hβ line after addition of water vapour to the source. Good fit of the experimental contour of Hβ with the theoretical contour based on Griem-Kolb-Shen's calculation was observed. Experimental shifts toward the violet were measured to be proportion to the square of the normal microfield. An empirical quadratic Stark effect constant C4= 5.0×10-14cm4/sec was determined from these data. The widths of the line profile bear a similar relation with the fields. Ratios of the width to shift, r/△, were found to remain constant in the range of experimental conditions studied. The value is r/△ = 10.4±0.6. Theoretical calculation of the shift of the upper term 42F due to the quadratic Stark effect perturbation of 42D term allows one to explain the quadratic dependence on field, but the values of shift are smaller in comparison with experimental data, indicating an additional contribution by electrons. The widths of the line have been compared with the theoretical formula of Lindholm and Griem et al's approximate formula. Simple estimate shows a better agreement with the latter.
THE STARK BROADENING OF BALMER LINES IN A HYDROGEN PLASMA PRODUCED BY INDUCED MAGNETIC FIELD
HONG MING-YUAN, YEH MOW-FOH, SUN HSIANG
1965, 125 (9): 1606-1618. doi: 10.7498/aps.21.1606
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The Stark broadening of Balmer lines in a hydrogen plasma produced by induced magnetic field has been investigated. A condenser bank discharging into the coil surrounding the discharge tube, produces an alternating axial magnetic field which ionizes, compresses, and heats the hydrogen in the tube. The working conditions are: initial pressure of hydrogen, 2.0×10-1mm Hg; charging voltage, 20 kV; discharge period, 14 microseconds; maximum current, 165 kA. Profiles of the spectral lines of Hβ and Hγ are studied by the photographic method. These lines are considerably broadened. In the whole luminous stage, the mean half-widths of Hβ and Hγ are 14-16? and 18-19? respectively, corresponding to an ion density of 1.7-2.5×1016cm-3. The experimental profiles agree better with Griem, Kolb, and Shen's theory than with Holtsmark's theory. Photo-electrical measurements show that the profile of Hβ changes with time, accordingly the ion density changes also. At the primary current maximum of the third half-period of discharge, the ion density reaches a peak value of 3.2×1016cm-3 which is 2.2 times the initial density of hydrogen atoms.
SUPERCONDUCTING FILMS IN A MAGNETIC FIELD
LEI HSIAO-LIN
1965, 125 (9): 1619-1637. doi: 10.7498/aps.21.1619
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The theory developed in reference [1] has been extended to thicker films. The compensation equation and current equation are derived for superconducting films in a magnetic field, on the basis of a model which assumes the energy-gap function to be constant over the whole film and by means of Schrieffer's technique. The equations obtained are applied to discuss the influence of an external magnetic field on the superconducting properties of a metallic film and its transition changes. The formulas for determining energy-gap, magnetic moment, and critical fields Hc, H(c1) and H(c2) which correspond respectively to equilibrium transition and to boundaries of supercooled and superheated region, are given. All the expressions have been reduced to the well-known results of the Ginzburg-Landau theory in the local limit and to those of reference [1] in the thin film limit. Non-local effects in the general case have been discussed in detail.
QUANTUM THEORY OF GALVANOMAGNETIC PHENOMENA IN ELECTRON-PHONON SYSTEM
LI JI-SHI, ZHANG SI-YUAN, ZHANG SI-JUN
1965, 125 (9): 1638-1652. doi: 10.7498/aps.21.1638
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By making use of the method of quantum field theory, the A.C. magnetoresistance, the Hall effect, and the cyclotron resonance phenomena in electron-phonon system are investigated. The relaxation times and effective masses, which depend on the frequency of external electric field ω and intensity of static magnetic field H, and the strict expression for the line shape of cyclotron resonance are obtained in this way. In our work, the effect of Coulumb interaction between electrons, the effect of quantization of orbital motion, and the influence of alternating electric field have been taken into account.
THE COUPLED-MODE THEORY OF WAVE PROPAGATION THROUGH FERRITE ROD WITH VARIABLE CROSS-SECTION
HUANG HUNG-CHIA, FAN DIAN-YUAN
1965, 125 (9): 1653-1667. doi: 10.7498/aps.21.1653
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In this paper, the authors have derived a general set of coupled-mode equations for wave propagation in a wave-guide partially filled with gyromagnetic medium. With these equations, they have investigated the problem of Faraday rotation in a longitudinally magnetized ferrite rod with tapering cross-sections at both ends. Additional problems, e.g., the reflection from the ferrite rod and the effect of geometrical irregularity of the rod on the Faraday rotation, have been subsequently attacked by the same coupled-mode approach. It is shown that the coupled-mode theory is admirably suitable for the important problems herein treated. It would be extremely difficult to discuss these problems with any standard method more commonly used in the study of microwave ferrites.
MECHANISM OF HIGH-TEMPERATURE DEFORMATION IN Al-Mg ALLOYS
KUO MOU-DUAN, DOU CHUNG-WEI, WANG CHI-MIN, WANG ZAI-FO
1965, 125 (9): 1681-1688. doi: 10.7498/aps.21.1681
Abstract +
The high temperature deformation of Al-3% Mg and Al-6% Mg alloys has been investigated by differential tensile tests. The activation energies, activation volumes and frequency factors at different temperatures have been obtained. The controlling deformation mechanism in the temperature range 250-400℃ is proved to be possibly due to the non-conservative motion of jogged screw dislocations. The deformation equation is ε=Nιjb2zAνexp{-(△Hs-ιjb2τ)/(kT)}. Thereafter the jog spacings, dislocation densities, jog densities and dislocation velocities at different temperatures are calculated for both alloys. In the above equation ε is the strain rate, b the Burgers vector, Z the coordination number, A the entropy factor, v an atomic frequency, △Hs the self-diffusion coefficient, τ the applied shear stress, k Boltzmann's constant and T the absolute temperature.
ASYMPTOTIC BEHAVIOUR OF SCATTERING AMPLITUDE AND HIGH ENERGY INELASTIC PROCESSES
KWO SHE-HUNG
1965, 125 (9): 1689-1696. doi: 10.7498/aps.21.1689
Abstract +
Assuming that the vacuum Regge poles become a complex conjugate pair when t-3. In order that the total cross sections approach constant values, the number of fireballs should increase with In s.
BRIEF REPORT
1965, 125 (9): 1697-1699. doi: 10.7498/aps.21.1697
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1965, 125 (9): 1700-1704. doi: 10.7498/aps.21.1700
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1965, 125 (9): 1705-1710. doi: 10.7498/aps.21.1705
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