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Vol. 20, No. 4 (1964)

1964-02-20
CONTENT
ON ELECTROMAGNETIC INSTABILITIES OF PLASMA
LOH CHYUAN-KONG
1964, 108 (4): 289-296. doi: 10.7498/aps.20.289
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In this paper, a strict and general instability criterion is obtained by analysing the geometric properties of the dispersion relation of electromagnetic waves in plasma with anisotropic velocity distribution. The criterion is applied to the cases of anisotropic temperature and current-carrying plasma. Finally, the relativistic correction of Weibel's formula is obtained.
ON THE FERROMAGNETIC RESONANCE LINE WIDTH CAUSED BY THE FLUCTUATION OF THE EXCHANGE INTERACTIONS
HSU DSEN-I
1964, 108 (4): 297-304. doi: 10.7498/aps.20.297
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In this work, the ferromagnetic resonance line width of a ferrite with two kinds of cations randomly distributed on a sublattice is calculated by taking into account the spatial fluctuation of both the spins and the exchange integrals. The uniform precession excited by the microwave field is scattered into degenerate spin waves by this inhomo-geneity. It is explained that the fluctuation of the pseudo-dipole forces considered by Clogston et al. was overestimated and is actually negligible in the present problem as comparing with the fluctuation of the exchange interactions. The result of our calculation not only gives rise to a large line width in the same order of magnitude as that observed with a number of inverted spinels, but also leads very naturally to an explanation of the noticeably small line width observed with the magnesium-manganese ferrite and the disordered lithium ferrite.
THE FIGURE OF MERIT FOR THE ALLOY-DIFFUSED PARAMETRIC DIODE
CHUO CHI-TSANG, SHIUH GEN-TWEN
1964, 108 (4): 311-326. doi: 10.7498/aps.20.311
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The figure of merit for the alloy-diffused parametric diode is analysed, with special reference to ordinary alloyed parametric diode. The important result obtained is the indication that the performance of parametric diode cannot be improved through increasing the capacitance-voltage sensitivity obtained by the alloy-diffusion technique.
THE SERIES RESISTANCE AND CUTOFF FREQUENCY OF DIFFUSED PARAMETRIC DIODE
SHIUH GEN-TWEN, CHUO CHI-TSANG
1964, 108 (4): 327-336. doi: 10.7498/aps.20.327
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In this paper, the series resistance and cutoff frequency of diffused parametric diode are analysed. The way of finding out the optimum impurity distribution for a given material has been indicated, and the way effectively to increase fc has been shown.
A STUDY OF ETCH-FIGURES OF DISLOCATION LINES IN MOLYBDENUM CRYSTALS
FONG DUAN, MING NAY-BEN, LI CHI
1964, 108 (4): 337-351. doi: 10.7498/aps.20.337
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Experimental results about dislocation etch-pits on {100}, {111}, and {110} surfaces of electron beam floating zone-melted molybdenum single crystals are described. Electrolytic etching reagents used in this work are mixtures of methyl alcohol, sulphuric acid, and chloric acid. Besides, etch-lines arranged in parallel sets and hexagonal networks are observed on {111} and {110} surfaces, these are interpreted as etch-figures of dislocation lines.An empirical rule for the interpretation of etch-figures of dislocation lines is deduced from observations. Observed etch-figures are projections on observation plane of dislocation lines in the etched layer, its widths depend on the distance between dislocation line-elements and original surface, so that an exaggerated perspective effect is obtained. Hence the arrangements of dislocation lines in space may be deduced directly from observed etch-figures. By means of multiple etching technique, some examples of dislocation arrangements in space are presented.Correspondance between etch-pits and sites of dislocation lines intersecting original surface has been studied. In general, such correspondance is observed by means of an etching-polishing-reetching technique. However, experimental results show that such correspondance may be violated in some cases. For instance, when the angle between a dislocation line and observation plane is less than a critical value (15°-24°), no etch-pit is observed. On the other hand, nodes of dislocation networks after prolonged etching, may be revealed as arrays of etch-pits. The significances of these results on the interpretation of etch-pits figures are discussed.The etch-figure method has been compared with other methods of direct observation of dislocation lines, its merits and demerits are discussed, and it is concluded that the etch-figure methods is superior to all other existing methods in the study of dislocations in metal crystals when the dislocation density is within the range from 104 to 108 cm-2.
ROLLING TEXTURES IN CUBICALLY ALIGNED NICKEL-IRON
CHANG S.Y., HO T.C., TAIL.C.
1964, 108 (4): 352-359. doi: 10.7498/aps.20.352
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An investigation of the rolling textures in recrystallized, cube-textured nickel-iron alloy containing 50 percent nickel and 50 percent iron has been carried out.The specimens used in the experiments were first heavily rolled and then annealed to give a cube texture. The textured specimens were again rolled with reductions of 10, 30, 50, 70, 87 and 93 percent. Pole figures were determined by using a counter X-ray diffractometer.The results are discussed in the light of lattice transformation, a model first proposed by Rowland.
A STUDY ON THE PHYSICAL MECHANISM OF THE "CARRIER EFFECT" IN SPECTROGRAPHIC ANALYSIS
HSU SHENG-MEI
1964, 108 (4): 360-367. doi: 10.7498/aps.20.360
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The possible role of certain carrier (Ga2O3,Na2CO3) on the intensity of spectral lines in various matrices such as graphite, U3O8, ZrO2, etc., was investigated. The resultsshow that, in any matrix there is a relationship between the carrier effect (logI/I0) and the ionization potential (V) of impurity elements. From the measurements of the arc temperature and degree of ionization, we believe that in the case of carrier distillation method the electric field must be considered. The addition of these carriers brings about a change of arc temperature as well as degree of ionization in the arc column, which leads to a more suitable condition for the excitation of many elements, resulting in an increase of the intensity of spectral lines, but it has no influence on the process of evaporation.
BRIEF REPORT
1964, 108 (4): 374-377. doi: 10.7498/aps.20.374
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1964, 108 (4): 378-380. doi: 10.7498/aps.20.378
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1964, 108 (4): 381-382. doi: 10.7498/aps.20.381
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1964, 108 (4): 383-386. doi: 10.7498/aps.20.383
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