Vol. 31, No. 1 (1982)
1982, 31 (1): 1-16. doi: 10.7498/aps.31.1
This paper discussed the lower-hybrid-drift instability in a simple magnetopause structure in which tbe charge separation electric field is completely neutralized and the total pressure is a constant. The magnetic field directions are assumed to be parallel each other crossing the magnetic boundary. The equilibrium distribution functions presented by W. Alpers is used to calculate the growth rate of the LHD instability and the field energy density. The anomalous resistivity is also evaluated. If the thickness of the magnetopause is near two Larmor radius of thermal ions, the instability growth rate is 0.26 ωLH (ωLH is the lower hybrid frequency) and the anomolous resistivity is 10-5 sec. As the thickness increases, the growth rate and the anomalous resistivity decrease rapidly.
1982, 31 (1): 17-29. doi: 10.7498/aps.31.17
The relations between the threshold values of ion-temperature-gradient instabilities and the temperature parameter of plasmas are investigated analytically in the slab and toroidal geometries separately. It is found that the threshold values increase rapidly when the ion temperature becomes much higher than the electron temperature. The change of the threshold values with respect to the ion temperature is quite similar for both geometric models. Our results are consistent with the PLT observations and also agree well to that of the numerical calculations.
1982, 31 (1): 30-37. doi: 10.7498/aps.31.30
A new method which can simultaneously determine the constituent and thickness of the alloy films using the X-ray EDS has been developed. The constituent is determined by the ratios of the kα intensties of elements in the film. The thickness of the film deposited on a NaCl substrate is measured by the attenuation of the ratios of Na kα intensity/Cl kα intensity. It is not necessary to use bulk standards of pure elements. This method has been applied to Cu-Si alloy films of different thickness deposited on NaCl substrate. Under various experimental conditions, the constituent and thickness data are determined satisfactorily.
1982, 31 (1): 38-49. doi: 10.7498/aps.31.38
The second and third order elastic constants of seven simple metals (Li, Na, K, Eb, Cs, Al and Pb) are calculated using the one-parameter Heine-Abarenkov model potential with the Hubbard-Sham dielectric function. The two adjustable parameters are determined from the experimental data of the elastic constant C44 and the lattice constant of the crystal at 0 K and zero pressure. The calculated results are in comparatively good agreement with the experiments or the theoretical calculations of other authors. Especially for Al, the present results of the third order elastic constants are closer to the experimental data than those found in the literatures.
In this paper, we use the Fokker-Planck equation, which is derived from the Master equation and has a diffusive fluctuation term, to discuss three chemical models' fluctuation under different situations. We point out: the fluctuation near equilibrium is local and Gaussian; as the system deviate from equilibrium, the fluctuations appear correlative at different points in space; Schlogl's trimolecular model has non classical exponents; but Schlogl's dimolecular model has classical exponents. The diversification of these fluctuations is determined by the property of the system itself. By the method used in this paper, we can treate these problems in a unified base, and, therefore, provide a solution to the question about critical exponents presented in the literature.
ANALYSIS AND CALCULATION ON THE PHYSICAL PHENOMENON ABOUT ELECTROMAGNETIC WAVES IN THE ANECHOIC CHAMBER
1982, 31 (1): 58-70. doi: 10.7498/aps.31.58
In this paper, we discuss some physical phenomena occured in the anechoicchamber—the absorbtion and reflection of an electromagnetic wave by the absorbingmaterials, the deflection of the reflected wave polarization, the interference of waves and the complex distribution of the voltage standing waves duo to this interference. The direct wave is used as reference of all the reflected wave, only the portion of every reflected wave in the direction of the direct wave polarization is considered. Then, in the case of multi-wave interference, we obtained the equations of the field amplitude, reflectivity level, cross-polarization characteristics, path loss uniformity as well as the curves o.f natural reflectivity level, which may be used in engineering design Finally, some typical experimental results are presented.
1982, 31 (1): 71-77. doi: 10.7498/aps.31.71
Semi-insulating GaAs substrates doped with chromium were implanted with 120-160 ke V28Si+ ions (1012-1013 cm-2 at room temperature. After thermal annealing, the carrier concentration and mobility profiles, residual damage and impurity levels of implanted wafer were determined by C-V method, back scattering technique and photo-1uminescence spectra. The results showed that the semi-insulating GaAs substrate selection and 28Si+ beam purity control are necessary to obtain reproducible and high activation implantation. Fabricated with multiple localized silicon implantation for both active and contact layer, GaAs dual-gate MES FET applicated in UHF TV tuner reached a noise figure of 0.9 dB and an associated gain of 10 dB at 1 GHz. The mobility profile and appropriate annealing temperature are discussed on the basis of the present experimental results.
1982, 31 (1): 78-89. doi: 10.7498/aps.31.78
The temperature gradient liquid phase epitaxy under a steady natural convection flow was introduced. The steady natural convection flow was caused by applying a horizontal temperature difference to the growth solution. The growth rate in this process was calculated using a simple model. It was found that the growth rate is directly proportional to the square root of the horizontal temperature difference and for Ga0.85Al0.15 As growth under the condition employed in the present work the growth rate is 1124 times as great as that predicted by the steady state diffusion theory and the deviation of epitaxial layer thickness is not more than 10% over the most part of area of growth layer. The experimental growth system designed for the temperature gradient liquid phase epitaxy under a steady natural convection flow was described. This system was used to grow thick Ga0.85Al0.15 As layers. The experimental result shows that the observed growth rate is directly proportional to the power 0.45 of the horizontal temperature difference and for Ga0.85Al0.15 As growth the observed growth rate is 156 times as great as that predicted by the steady state diffusion theory and is one-eighth as great as that predicted by the convection theory and at a relatively small horizontal temperature difference the deviation of epitaxial layer thickness is in agreement with the calculated value by the convection theory. The calculated growth rate is higher than the observed growth rate. That is attributed to some approximations made and some indefinite parameters used. Owing to an increase in growth rate the present work was able to grew thick Ga1-xAlx As layers at the temperature which is 135-210℃ lower than that used for the similar work.
THE PROBLEM OF EIGHT-FOLD MULTIPLE SOLUTION RESULTING FROM THE SPECIAL ARRANGEMENT OF HEAVY ATOMS IN CENTROSYMMETRIC CASE
1982, 31 (1): 90-96. doi: 10.7498/aps.31.90
In low symmetry system, eight-fold multiple solution is an extreme case of multiple solutions on the positions of light atoms caused by the special arrangement of a single set of equivalent heavy atoms. This extreme case occured in the determination of the crystal structure of TIP.In this paper, the principle and practical procedure of solving this problem are given in detail.
VARIATION IN L, M, N INNER-SHELL ELECTRON BINDING ENERGIES OF RARE-EARTH ELEMENTS IN VALENCE TRANSITION
1982, 31 (1): 97-103. doi: 10.7498/aps.31.97
In the valence transition phenomena, the occupation number of the 4f electrons of the rate-earth atoms will change "continuously" or discontinuously under the condition of different temperatures, different pressures or different compositions (as chemical compounds). Owing to the different occupation number of the 4f electrons, the binding energies of the inner-shell electrons of the rare-earth atoms will vary. We, here, apply a relativistic Dirac-Slater self-consistent field method to calculate the variation of the inner electron binding energies due to valence transition.
THE CORRESPONDANCE BETWEEN GROWTH STRIATIONS AND STRUCTURES OF FERROELECTRIC DOMAINS IN CZOCHRALSKI-GROWN LiNbO3 SINGLE CRYSTALS
1982, 31 (1): 104-108. doi: 10.7498/aps.31.104
The variations of ferroelectric domain structures related to rotational striations and power striations are observed. The one-to-one correspondance between rotational striations and structures of ferroelectric domains have been demonstrated. The distribution of solute concentration in rotational striation is measured by means of energy dispersive analysis of X-ray in scanning electron-microscope, and we reached the conclusion that the ferroelectric domain structures are dependent on the gradient of solute concentration. The coupling of the spontaneous polarization with the gradient of solute concentration is experimentally demonstrated for the first time.
The light emitted from a Keplerian ring around the objects with strong gravitational field should be affected by Doppler shift, gravitational redshift and deflection of light. The line profiles for a faraway observer are dominated by these effects. In this paper the precise solutions of line profiles for the Keplerian rings in the Schwarz-schild case have been obtained by means of the kinetic equation for photons.
1982, 31 (1): 115-120. doi: 10.7498/aps.31.115
Monte Carlo method has been used to evaluate the X-ray intensity distribution funetion in freestanding thin films and in surface layer of same thickness of the same material. A simple equation of the X-ray emitting intensity from a thin film on substrate has been proposed to correct the influence of Z. A. P. on the determination of film thickness. The accuracy of the present measurement is higher than that of methods previously. developed. Experimental results are presented for Ta2O5 film on GaAs and for ZrO2 on Si. They are in agreement with those obtained by ellipsometry.
1982, 31 (1): 121-125. doi: 10.7498/aps.31.121
A phase diagram of the alloys of the gadolinium-indium binary system was studied by differential thermal analysis, X-ray diffraction method and microscopic observation. The following six intermediate phases were verified: Gd3In,Gd2In,Gd5In3,Gdln,Gd2In3 and Gdln3. There are five eutectic transformations corresponding respectively to about 12 at % In (eutectic temperature 988℃), 30.5 at % In (1151℃), 38.5 at % In (1114℃), 64.5 at % In (1010℃). The eutectic on the In-rich side is degenerate. The decomposing temperature of the compound Gd2In3 formed by peritectie reaction is Tper= 1107℃. The periteetoid reaction 2Gd2+GdIn←→Gd5In3 occurs at 1071℃. Neither In in Gd nor Gd in In shows any detectable solid solubility.
1982, 31 (1): 126-131. doi: 10.7498/aps.31.126
The recovery behavior of the 60% deformed iron in various stages of isochronal annealing has been investigated by positron annihilation technique. The experimental results show that both the average life time τ and the lineshape parameter S of the positron annihilation may be expressed as functions of annealing temperatures. Life time τf of the positron annihilated in the perfect lattice is found to be 111 ± 1 ps, while τd in the defect lattice to be 162 ± 1 ps. Trapping rates and τ1 are calculated, these values are in good agreement with those predicted by trapping theory. It is obtained from the calculation that the rang of fractional concentration of defect trapping positron is 10-7-10-4.
THE PROBLEM OF FOUR-FOLD MULTIPLE SOLUTION RESULTING FROM THE SPECIAL ARRANGEMENT OF HEAVY ATOMS IN CENTROSYMMETRIC CASE
1982, 31 (1): 132-137. doi: 10.7498/aps.31.132
The priciple and practical procedure of solving the pnoblem are given in detail.
1982, 31 (1): 138-142. doi: 10.7498/aps.31.138
The refractive index dispersion data of the single crystal yttrium iron garnet are obtained from reflectivity measurements on natural crystal faces. The esults are analyzed using Sellmeier three-term oscillator and power series expression. The deviation of measured and calculated refractive index is about 0.003 over the wavelenth range 0.5 to 5.5 μm