Vol. 33, No. 5 (1984)
1984-03-05
CONTENT
1984, 33 (5): 593-601.
doi: 10.7498/aps.33.593
Abstract +
The functional relations have been presented between the complex amplitude (including polarization) of reflected wave on the one hand and amplitudes, polarizations of pump and probe waves, the third-order nonlinear susceptibility on the other hand, for degenerate four-wave mixing (DFWM) in isotropic medium, in which the polarizations are linear and/or circular, and the geometry is collinear or non-collinear. In the non-collinear geometry, when the polarizations of pump waves are parallel to each other, one can determine the ratio x1111/x1221 from the angles between polarization directions of probe and reflected waves; when the polarizations of pump are circular polarizations of the same handedness, one can get the ideal complex conjugate wave in this geometry. In the collinear geometry, there are always some non-conjugate component in the reflected wave, and the functional relation between reflection coefficient of amplitude and the thickness of sample can have the form of tangent function, hyperbolic tangent function and linear function; when the polarizations of pump waves are parallel to each other and |x1221|> |x1122|, this geometry is capable of generating self-oscillation; when polarizations of pump are circular ones of different handedness, DFWM acts as an ideal plane-mirror for probe wave with circular polarization, etc. The results can be used to explain some well-known experimental results and provide some theoretical guidance for designing new experiments.
1984, 33 (5): 602-611.
doi: 10.7498/aps.33.602
Abstract +
In this paper, the dynamic characteristic of the buried crescent InGaAsP/Inp laser is analysed by the computer simulation method. The dependences of the threshold current and the single model cut-off condition on the structure parameters such as the active layer thickness (centre) d0, the channel width W, the cavity length L, the stripe width s, and the material resistance Rx are obtained.Based on the simulation analysis, the approximate expression between the structure parameters and the threshold current is provided. From this, the laser physical characteristic can be estimated simply and directly, and the model of injection carrier Gaussian profile is also propounded. Using this model, the current spreading and the gain profile were correctly calculated, and a series of analytical expressions about the maximum gain gmax, the threshold current density Jth, the mode gain Gth, the optimal active layer thickness d0,min and the optimal threshold current density Jth,min ate derived. According to the analysis mentioned above, the optimal design parameters for this type of laser are obtained as follows:d0= 0.15-0.2 μm, W = 2-4 μm, L = 200 μm and s= 10-15μm.
1984, 33 (5): 612-620.
doi: 10.7498/aps.33.612
Abstract +
By using Fresnel diffraction, we get the imaging and pseudo-phase-conjugation properties of the optical array with large radius of curvature which is composed by many optical elements. It is shown that the compensation for distortion does not result from the production of the phase conjugate reflected waves, but from the interaction of retro-reflective waves.
1984, 33 (5): 621-628.
doi: 10.7498/aps.33.621
Abstract +
The depth distribution of X-ray production φ(ρz) in some alloys was computed by means of Monte Carlo method and the modified expression of the total scattering cross-section and used for quantitative electron probe microanalysis. We have carried out computation on twelve kinds of binary alloys, one ternary alloy and carbon in the silicon carbide. The results given in the present work are preferable to both ZAF method and Shimizu's method. Especially, the computed results of carbon is much better than that computed by ZAF method. It follows that the present method can be used for quantitative microanalysis of light elements.
1984, 33 (5): 629-638.
doi: 10.7498/aps.33.629
Abstract +
Recently the sextupoles have drawn much attention in literatures, for sextupoles can be used to compensate for the third-order spherical aberration of round lenses. In the present paper, the aberration theory of a combined magnetic round lens and sextupoles system with superimposed fields has been studied. Defining an inner product in the complex number field and using the complex representation and differential operators, we have treated both the Guassian dioptrics and the electron optical aberrations up to the fourth-order in this combined system comprehensively. All aberration coefficients have been derived in explicit form.
1984, 33 (5): 639-644.
doi: 10.7498/aps.33.639
Abstract +
In this work, the empirical dependances of superconducting parameters and phonon spectrum parameters on the Hall Coefficient,and the problem on the Tc in amorphous non-transition metals are studied. It is found that the relative rise of Tc depends linearly upon the relative increase of λ and the Tc increases with the increase of the cut-off frequency ( ω0 ) of the phonon spectrum. In addition, although the Tc for non-transition metals can be raised by softening phonon spectrum, but there is slim hopes to obtain amorphous superconductor having high Tc for non-transition metals including metal Be. The description of electron properties and strong coupling effects which present in upper critical field Hc2 and energy gaps, 2△0 , of amorphous superconductors are also discussed.
1984, 33 (5): 645-653.
doi: 10.7498/aps.33.645
Abstract +
Neutron diffraction measurements have been made on metallic glasses Fe83B17 using polarized beam and on Ni64B36 using non-polarized beam. The partial structure factors Sij(Q) and partial reduced RDF for these two glasses are obtained from the scattering patterns, the atomic short range structural parameters are also obtained. These curves and parameters are discussed in relation to current models of metallic alloy glasses. The neutron scattering intensities of a simple model have been simulated and the results compared with those obtained from the experiments.
1984, 33 (5): 654-661.
doi: 10.7498/aps.33.654
Abstract +
Ab initio calculations of wavefunctions for first- and secondrow diatomic hydrides, and for first-row homonuclear and heteronuclear systems have been performed employing the same Gaussian basis set. This is the first one of a series of papers. In this paper the electronic wavefunctions, orbital energies and total energies of the diatomic hydrides are obtained at the experimental and (or) theoretical internuclear separations. These wavefunctions are solutions to the Restricted Hartree-Fock equations in the form of expansion with Double Zeta Contracted Gaussian functions. The repertory of states includes the ground states AH, a few low-lying excited states AH*, and positive and negative ions AH± , where A denotes the elements Li through F and Na through Cl. The calculations are restricted to states involving either closed-shell electron configurations or open-shell configurations with one incompletely filled open shell. Tables of electronic wavefunctions of three ground states AH, as examples, are presented.
1984, 33 (5): 662-670.
doi: 10.7498/aps.33.662
Abstract +
In this paper, the electrical effects of gold at the silicon nitride-silicon interface and the heat treatment behaviour of these effects are studied systematically. The results of electron spectroscopy analyses of the MNS structure are also presented. In addition, the action mechanism of gold at this interface is investigated.
1984, 33 (5): 671-677.
doi: 10.7498/aps.33.671
Abstract +
This paper deals with study of period-doubling bifurcation and chaotic behavior under the control of freqency. All structure of bifurcation and chaos can be shown on the V0-ω parameter plane by the method of frequency sweeping. The normal and inverse bifurcation sequences are fully symmetric. On the plane of the control parameters there is a point where the values merge to a unique value. The proposed method is simple and fast, and can be used to study the behavior of the chaotic dynamic systems. Not only can it be used to measure quantitatively the values of the convergence ratio δ and the rescaling factor α, but also to observe qualitatively some periodic windows which exists in the chaotic bands, as well as intermittent chaos. Bifurcation and chaos are the frequency response of the nonlinear systems.
1984, 33 (5): 678-683.
doi: 10.7498/aps.33.678
Abstract +
The stochastic magnetic field modifies the interaction of the waves with the electrons, and the wave-driven velocity diffusion may be effected. However, the mechanisms and the results are not all the same, if the value of correlation time of the stochastic magnetic field is different. In general, due to the effects of stochastic magnetic field, the transverse component of the electric field of waves can contribute to the longitudinal velocity diffusion, the resonant peaks of diffusion coefficient in the case of ∈>1 , the oscillating effects of diffusion coefficient are weakened. For the waves propagating nearly perpendicular to the magnetic field the effects of stochastic magnetic field on the velocity diffusion driven by the waves may be important.
1984, 33 (5): 684-688.
doi: 10.7498/aps.33.684
Abstract +
The analysis of the present note shows that the curves of the longitudinal critical current of an ideal Type Ⅱ superconducting plate are in the form of an inverted letter U or take such a shape as to show the peak effect, depending on whether the thickness of the plate is larger or smaller than the critical thickness d0.
1984, 33 (5): 689-693.
doi: 10.7498/aps.33.689
Abstract +
Our samples are prepared with low oxygen-and low sulfur-content pure iron or antimony and minute cerium as additive as the case may be by livatation melting method. The existent state of Ce in the pure iron and the effect of Ce on Fe-Sb alloy are examined. The results of our investigation are as follows:(1) We find that the anticorrosive ability of crystal boundary of ferrite can be significantly improved due to the adding of cerium. At the crystal boundaries of ferrite the existence of Ce can not be detected; but meshes have been found at the boundaries of the δ-phase formed at high temperature. It is proved that the meshes has the constituent of CeAlO3 through electron diffraction anlysis.(2) The crystal boundaries of Fe-Sb alloys may be cleaned by adding Ce. After adding Ce, Fe3Sb2 is no longer found at the crystal boundaries of the alloys but there is CeSb in bulk crystals as compared with those alloys without Ce.
1984, 33 (5): 694-695.
doi: 10.7498/aps.33.694
Abstract +
Distribution of defects caused by hydrogen in silicon single crystals is investigated by means of X-ray projection topography. It has been observed that the defect density and its size in new exposure surface area are similar to those in the crystal interior, which are different from those observed in thin wafer. These results are discussed briefly.
1984, 33 (5): 696-700.
doi: 10.7498/aps.33.696
Abstract +
It is shown by means of electron diffraction and high resolution lattice imaging that there are 9R, 10H, 16H, 20H, 21R, 44H and 2H structures in cast Ni3(Tix,V1-x) alloys. These phases have the following orientation relationships with primary phases Ni3Ti and Ni3V: {001}L.P∥{001}(Ni3Ti)∥{112}(Ni3V);〈100〉L.P.∥〈100〉(Ni3Ti)∥〈110〉(Ni3V) After prolonged annealingat high temperature these phases would transform into 9R.
1984, 33 (5): 701-705.
doi: 10.7498/aps.33.701
Abstract +
Recently the metallic magnetic powders have been recognized to be better materials for high density magnetic recording. Superior quality magnetic tapes have been made with these metallic powders. But there are some problems remined they are easily corrodible and are rather difficult to disperse in the lacquer. To study the causes of chemical instability of these materials and to prevent their corrosion are very important for their applications in practice. The causes of chemical instability of metallic powders are studied by M?ssbauer effect and other experimental methods. Their corrosion may be prevented basically. This study will provide some useful data for their practical applications.
1984, 33 (5): 706-709.
doi: 10.7498/aps.33.706
Abstract +
In this paper special light diffraction phenomena and diffraction bands and rings observed when a laser beam passed through a LiKSO4 single crystal are reported. These phnomena were inverstigated in various experimental conditions. It is concluded.that the phenomena are caused by volume phase gratings with wave vectors perpendicular to c axis in LiKSO4 It is tentativly assumed that a fluctuation of the elastic strain in the direction perpendicular to c axis in LiKSO4, and therefore a related fluctuation of the dielectric tensor is produced in that direction through the photoelastic effect. As a conseqence, anisotropic volume phase gratings is formed in the crystals. No explanation is given to the appearance of secondary rings both inside and outside the main diffraction as the laser beam incident nearly normal to the c axis.
1984, 33 (5): 710-713.
doi: 10.7498/aps.33.710
Abstract +
Having observed directly the fibre channels in which the ions transport and their relaxation with a polarizing microscope, we have provided a strong evidence for the model of the channel conductance in the c-direction. At the same time, we observed that a rotation of π/2 in the polarization of transmission light only takes place near the channels for α-LiIO3. It is sure that the grating which produces light diffraction beam subtending large angles and turning its polarization to π/2 consists of the many channels.
1984, 33 (5): 714-717.
doi: 10.7498/aps.33.714
Abstract +
MoxGe1-x and MoxSi1-x films are prepared by d.c. getter sputtering method onto liquid nitrogen cooled substrate. The compositions forming the amorphous state are found to be Ge>22at% and Si>18at% respectively. The superconducting transition temperature decrease with the increase of Ge, Si content from 6K to 3K in the amorphous state.The crystallization temperature of a-Mo77Ge23 is 780℃ and that of a-Mo78Si22 is 480℃.
1984, 33 (5): 718-721.
doi: 10.7498/aps.33.718
Abstract +
In this letter, we derive a multi-harmonic modulation solution of the incommensurate phase of a sinple model by a method like that used to solve pendulum problem in mechanics. This solution reduces to single-harmonic modulatioi at the of high temperature limit and transforms into kink solution at the of low temperature limit. The basic wave-vector decreases monotonously with temperature as observed in experiment.
1984, 33 (5): 722-728.
doi: 10.7498/aps.33.722
Abstract +
A kind of singular perturbation method is used to remove secular terms in Hilbert expansion and Enskog expansion of the normal solution and those in Grad expansion of the "initial layer" solution of Boltzmann equation (B.e.). The problem of solving B.e. in the "boundary layer" is reduced to that of solving a set of linear algebraic equations.
