Vol. 31, No. 3 (1982)
1982, 31 (3): 271-277. doi: 10.7498/aps.31.271
In this paper, we discuss the special structures of dislocations in h.c.p. metals. Two sets of dislocations that lay on two parallel non-basal slip planes will change their shape soasto become zigzag and form regular dislocation structures if the spacing of the slip planes is smaller than one quarter of the distance between the dislocations in the dislocation array. Under TEM observation, these structures appear to be regular dislocation networks that present double lines in one direction. Two of these dislocation networks in α-Ti were observed and others were shoAved schematically.
INVESTIGATION OF THE DEFECTS IN SILICON SINGLE CRYSTALS GROWN BY FLOATING-ZONE METHOD IN THE ATMOSPHERE CONTAINING HYDROGEN
1982, 31 (3): 278-284. doi: 10.7498/aps.31.278
Defects in dislocation-free silicon single crystals grown by floating-zone method in the atmosphere containing Ar-H2 or H2 were investigated by means of chemical etching and X-ray projection topography. It has been found that anomalous etch pits and defect density are closely related to the hydrogen content. (Change of the defect density with hydrogen content shows a maximum at approximately 10% hydrogen for ay-grown crystals. After annealing at high temperatures, the defect density in the inner part of the crystal is found to be more than that at the surface and also more than that in as-grown state when hydrogen content is greater than 25% in the atmosphere.) Defects in annealed crystals grown in the pure hydrogen atmosphere have been observed. The relationship between some defects showing in topographs and etch patterns was found. Effect of annealing on wafer with these defects was also observed. Finally, clustering and precipitating of hydrogen have been discussed. Dislocation loops formed at precipitate-matrix interface were described. The process of motion and interaction of the loops as well as the forming of multi-centre loops at high temperatures were also discussed briefly.
AN ALTERNATIVE DERIVATION OF COHERENT-POTENTIAL APPROXIMATION FOR DISORDERED ALLOYS-TIGHT BINDING MODEL
1982, 31 (3): 285-293. doi: 10.7498/aps.31.285
The coherent-potential approximation (CPA) for both single-particle and two-particle Green's functions are rederived using locator expansion method proposed by Matsubara and Toyozawa. Instead of using self-contained cumulant expansion to treat the excluded volume effects for atoms, we use a diagrammatic method with the idea first proposed by Yonezawa. A systemmatic method is used to generate self-consistent equations for all single-site diagrams. We emphasis our treatment for two-particle Green's function which can be extended to obtain the corresponding CPA equation for electrical conductivity in liquid metals and amorphous solids.
1982, 31 (3): 294-310. doi: 10.7498/aps.31.294
A tight-binding model is used to obtain the electrical conductivity for liquid metals and amorphous solids within the framework of coherent-potential approximation. Following the method developed in our previous paper, the approximated equations for averaged two-particle Green's function of a lattice-gas model are obtained with short-range order for atoms included. The corresponding equations for liquid metals and amorphous solids are reduced by taking the limit of the lattice-gas model. Since the self-consistent equations so obtained contain all single-site diagrams, they have all the properties of the coherent-potential approximation.
The massive and massless boson bound states in Kerr metric are discussed. It is found that the massless boson cannot be attracted by Kerr black hole to form bound states. In extreme Kerr geometry and large l cases, our results are in agreement with that of deFelic's, but we extend his result to arbitrary l and non-extreme Kerr geometry. For massive bosons, if the bound state conditions are satisfied, it is possible to form bound states in the extreme Kerr metric. Its energy mode, wave functions and bound states conditions are given.
1982, 31 (3): 318-327. doi: 10.7498/aps.31.318
Using semiclassical theory to treat the distributed feedback dye laser, we obtain nonlinear wave-coupling equations and the corresponding analytical solutions as well as the threshold relation. Some physical phenomena such as spatial hole burning and mode-competition are analyzed.
We report here the experimental results of high order coherent Raman spectra (CRS) in the ealcite using a YAG laser CARS system. CARS spectra from the 1st to the 6th order and coherent Stokes Raman spectra (CSRS) from the 1st to the 2nd order and the backward CARS spectra were observed. Factors affecting the high order CRS and related problems are considered.
1982, 31 (3): 335-347. doi: 10.7498/aps.31.335
In this paper, we show that a simple variational method proposed by Huybrechts is also valid for the surface or interface weak coupling polaron in polar crystals. The mass change and the binding energy of the surface polaron, which are given by expressions (27) and (35) in the text respectively, are dependent on the dielectric costant ε0, ε∞1,ε∞2 and the Fr?hlich coupling constant α. It is shown that the surface polaron, as compared to bulk polaron, have small binding energy and large state radius.
1982, 31 (3): 348-354. doi: 10.7498/aps.31.348
Using Hartree-Fock-Slater potential instead of Thomas-Fermi potential, a normalized formula of electronic stopping power is derived. Combined with the idea of effective atomic number, a correlate formula of electronic stopping power Se(E) and energy is obtained. The oscillation of Se(E). with atomic number of ions or target atoms are quantitatively calculated on the basis of the former formula. The results coincide well with experimental data in the literature. By using the later formula, the Se(E) of a variety of ion-target systems are quantitatively calculated. As compared with the formula in reference , the present results agree more satisfactorily with the experimental values and fit a broader range of energy.
THE SPACE-TIME CORRELATION OF THE FLUCTUATION IN A CHEMICAL REACTION SYSTEM (I)——FLUCTUATION, DIFFUSION AND WARES
1982, 31 (3): 355-368. doi: 10.7498/aps.31.355
In this article, the question about how to describe the space correlation of the fluctuation in a chemical reaction system has been analysed. Eeferring to the reaction-diffusion equation., we have successfully introduced the diffusion or pressure terms into master equation of the probability distribution function of density. Solving this master equation for infinite medium, a series of waves have been obtained. The first branch is the average density wave which has already been obtained from the reaction-diffusion equation. It is just the acoustic wave in gases. Other branches decribe the propagation of the fluctuation moments of the local density. They present the propagation processes of the local distortion of the probability distribution function. The method to solve the initial problem of the master equation have also been discussed.
THE SPACE-TIME CORRELATION OF THE FLUCTUATION IN A CHEMICAL REACTION SYSTEM (II)——THE CRITICAL BEHAVIOR OF NON-LINEAR SYSTEMS
1982, 31 (3): 359-385. doi: 10.7498/aps.31.359
Based on the theory developed in the first paper of this series, we have discussed the influences of the fluctuation waves on the critical behavior of a non-linear chemical reaction system. For this purpose, the usual bifurcation theory has been further developed and some divergence problems has been eliminated by renormalization.Taking the trimolecular model as the concrete object, the stability of the homogeneous steady state has been analysed in detail, and, in addition, we also discussed the possibility that the space structure of the density and fluctuation for a simpler case could appear.
A SCHEME OF HOLOGRAPHIC METHOD FOR OBTAINING A SINGLE MASK FOR REALIZATION OF GENERALIZED TRANSFORMS
1982, 31 (3): 386-392. doi: 10.7498/aps.31.386
A scheme of multi-exposure holographic method for obtaining a single mask for realization of a kind of unitary transforms is suggested. The formula of signal-to-noise ratio of the transform due to masks of this sort is deduced from a statistical point of view.
1982, 31 (3): 393-396. doi: 10.7498/aps.31.393
In this paper, we generalize the method proposed in  to solve the phase retrieval problem of spatial correlation functions in optical systems. A set of equations for determining the phase of the correlation functions is given. Using these equations and the iteration computing method, the phase of correlation functions can be determined. It can be shown that, if the transmission matrix K is unitary, in the coherent limit, the equations derived in this paper turn out to be that obtained in .
1982, 31 (3): 397-403. doi: 10.7498/aps.31.397
In the investigation of the interaction of the intense CW and pulsed CO2 laser with targets, we have studied first the phenomena on targets and observed the forming-time of the crater and the processes of torsion of the direction of the laser plume produced by CW laser. We have also observed the development of the plasma, the air breakdown and the unluminous phenomena such as the plume and shock-wave produced by pulsed laser etc.The device of the framing high-speed interferography with pulsed He-Ne laser was used.
PARAMAGNETIC RESONANCE STUDY ON TRANSITION METAL IONS IN PHOSPHATE, FLUOROPHOSPHATE AND FLUORIDE GLASSES(I)——Cr3+,Mo3+
1982, 31 (3): 404-409. doi: 10.7498/aps.31.404
The ESR of Cr3+ in phosphate, fluorophosphate and fluoride glasses has been studied. The effective g factors of Cr3+ have been calculated with the Spin-Hamil-tonian. It is pointed out that the low-field spectra resulted mainly from transition between two Kramers doublets. Hamiltonian parameters have been determined: D=0.15-0.4 cm-1, E/D=0.15-0.3; zero-field splitting: 0.3-0.8 cm-1. In this paper, the ESR of Mo3+ ion in phosphate glass is also reported.
PARAMAGNETIC RESONANCE STUDY ON TRANSITION METAL IONS IN PHOSPHATE, FLUOROPHOSPHATE AND FLUORIDE GLASSES (II)——Co2+, Ni2+
1982, 31 (3): 410-414. doi: 10.7498/aps.31.410
The BSE of Co2+ in the three kinds of glass has been observed at 77 K, it is shown that the Co2+ ions are mostly situated on tetrahedral sites. We conclude the order of the effective g value obtained from the experiments is related to a slight change of the chemical bonding nature between the central ions and the ligands. In addition, the ESR of Ni2+ in fluorophosphate glass has been observed and its spectrum is identified. A detailed calculation with the spin-Hamiltonian is carried out, and it explains why the ESR signal of Ni2+ in most oxide glasses can hardly be observed.
1982, 31 (3): 415-418. doi: 10.7498/aps.31.415
The relationship between the dislocations, the inclusions and the growth striations in YAG single crystals were studied with birefringence topography. The experimental evidence shows that the inclusions are adsorped preferentially at the outcrops of dislocations at the solid-liquid interface and the relative sizes of the inelusions correspond to the heights of growth-steps which are related to the normal components of Burgers vectors of dislocations.