Vol. 29, No. 10 (1980)
1980-05-20
CONTENT
1980, 29 (10): 1237-1244.
doi: 10.7498/aps.29.1237
Abstract +
In order to interpret the EBIC (electron beam induced current) photographs of scanning electron microscope, it is found nacessary to take the effect of photo injected carriers from forward biased pn junction into consideration. In this paper, results of constrast observation on a series of EBIC photographs of a trasistor at different levels of applied voltage are discussed. Based on the Bbers-Moll model for transistors together with some additional assumptions, we have been able to derive equations capable of describing the saturation current, effects of photo injected carriers from forward biased and reverse biased pn junctions. The theoretical analyses are qualitatively in agreement with the experimental results.
1980, 29 (10): 1245-1253.
doi: 10.7498/aps.29.1245
Abstract +
In this paper, the properties of a slow exciton in a polar crystal are discussed. The previous work of the author is generalized to the case that the electron mass is not equal to the hole mass. A perturbation method developed by Haga is used. In the approxiamation that the interaction of phonons of different wave vector in the recoil effect can be neglected, the wave function in the second order approxiamation is derived, and the electrostatic pontential is also calculated.
1980, 29 (10): 1254-1262.
doi: 10.7498/aps.29.1254
Abstract +
The correlation functions and kinetic equation for a plasma immersed in a stochastic magnatic field are derived. Based on our equation, the transport phenomenon are discussed.
1980, 29 (10): 1263-1274.
doi: 10.7498/aps.29.1263
Abstract +
The analytic solutions and numerical solutions of the equations of magnetic surface with fixed-boundary conditions are solved for the equilibrium plasma. The pressure, the velocity and the magnetic field fluctuations are evaluated with the simplified Lax-Wendroff method. The linear growth rates, the average β and βp, and the safety factor are obtained. We find that (1) plasma with concave currents profiles is more stable than that with uniform currents profiles, and plasma with convex currents profiles is least stable; (2) plamsa with diamagnetic currents is more stable than that with paramagnetic currents.
1980, 29 (10): 1275-1282.
doi: 10.7498/aps.29.1275
Abstract +
In this work, the structures of the amorphous alloys Fe5Co70Si15B10,Fe78Si1OB12 and Fe80B20 were analysed by X-ray diffraction method. From the diffraction intensity data the structure factors and radial distribution functions (RDF) of these materials were calculated.In order to obtain partial radial distribution functions (PRDF) of the binary alloy Fe80B20, the first peak of the alloy was fitted using a sum of two Gauss type functions. One of them describes the PRDF of the Fe-Fe atom pair, and the other describes the PRDF of the Fe-B atom pair.As the results of fitting, the average number of nearest neighbor atoms and most probable distance between two atoms were determined for each kind of atom pair. The curves of PRDF and the values of those parameters agree satisfactorily with the results obtained by other author using anomalous X-ray diffraction technique.
1980, 29 (10): 1283-1292.
doi: 10.7498/aps.29.1283
Abstract +
The mechanism of the formation of the defects during heat treatment in single silicon crystal, which had been grown by floating zone method under pure hydrogen, have been studied by means of X-ray topography, infrared absorption spectrography and chemical etching method.Three kinds of Si-H bonds were observed in the as-grown crystal, their infrared absorption peaks were at 4.55 μm, 4.75 μm and 5.13μm respectively. During heating these Si-H bonds were broken up gradually and dis appeared at last. The disappearing temperature of 5.1μm, 4.55 μm, and 4.75 μm absorption peaks were 450℃, 600℃ and 700℃ respectively.The heat-treatment defects were originated from hydrogen precipitation in the crystal. The sequence of the precipitation process was found to be as follows: Si-H bonds were broken at first, and then hydrogen diffused and coalesced together. The activitation energy of the precipitation process was found to be 2.4 eV (56000 cal/mol).Due to hydrogen preciptation, the prismatic dislocation loops were formed around hydrogen precipitates at definite temperature (about 600-700℃).
1980, 29 (10): 1293-1300.
doi: 10.7498/aps.29.1293
Abstract +
The phase equilibrium of pseudo-binary system LiIO3-HIO3 has been investigated by means of DTA, TGA and X-ray diffraction. The thermal properties and crystal structures of solid solutions based on α-LiIO3 and 2LiIO3 ·HIO3 are studied. 2LiIO3·HIO3 is isomorphic with α-LiIO3, belonging to hexagonal system. The space group is P63. The lattice parameters are: a=5.555?, c=4.953?. The parameter c decreases and parameter a increases with the HIO3 content. Compared with α-LiIO3, IO3- group expands along plane x-y and compressed along z-axis, i.e., the bond angle O-I-O becomes larger. 2LiIO3 ·HIO3 which is physicochemically different from α-LiIO3, is a new compound in the system LiIO3-HIO3, 2LiIO3·HIO3 does not form continuous solid solution with LilO3.
1980, 29 (10): 1301-1306.
doi: 10.7498/aps.29.1301
Abstract +
In this paper, we analyse the problem of the optical realization of Walsh transformation, and give the design of the optical system which is composed of holographic lenses and can be used to realize the 8×8 complex Walsh transformation in two-dimensional space.
1980, 29 (10): 1307-1314.
doi: 10.7498/aps.29.1307
Abstract +
The Walsh transformation has been experimentally carried out with coherent optical system. A five-plane coherent transformation device is designed, 1 - dimensional 8-sequence Walsh transformation is realized, the Walsh transform-spectrum is given. This design may be applied in principle to two-dimensional Walsh transformation.
1980, 29 (10): 1315-1322.
doi: 10.7498/aps.29.1315
Abstract +
Initiated from Graham's and Landauer's criticism, we discuss the problem of applicable range and practical value of the Glansdorff-Prigogine criterion and of the theorem of minimum entropy production in this paper. We point out that the Glansd-orff-Prigogine criterion as a thermodynamic theory is rigorous, but in the practical problem of many variables, it has no applicable value. And, the applicable range of the theorem of minimum entropy production is much smaller than that of other theorem's in the linear non-equilibrium thermodynamics, therefore, to use it as a principle is not adequate. But landauer's criticism about the theorem of minimum entropy production is wrong.
TRANSPORT PROCESS UNDER STRONG MAGNETIC FIELD AND TWO STATIONARY SOLUTIONS OF THE LIOUVILLE EQUATION
1980, 29 (10): 1323-1332.
doi: 10.7498/aps.29.1323
Abstract +
In this paper, we discuss the problem of two stationary solutions of the Liouville equation when an external field is present. We show that the key point for calculating the transport coefficient by the Kubo formula is: before completing the integral over time, the time behavior of the correlation function must be expressed in terms of the theory of approach to equilibrium. With this point, being considered, it is then possible to derive the correct expression for transport coefficient. Using this method, we calculate once again the conductivity under strong magnetic field that had been discussed in reference [1], and obtain a correct non-vanishing result.
BRIEF REPORT
1980, 29 (10): 1333-1337.
doi: 10.7498/aps.29.1333
Abstract +
It is pointed out that zph≡F(-ωph-2 is generally a branch point of the inverse function of the function z=F(y)≡∫0(ωph)(ω2y)/(ω2y+1)g(ω)dω, where g(ω) is the normalized effective phonon spectral function of the system. There-fore it should be taken into account in evaluating the radius of convergence of the series for superconducting critical temperature of the system.
1980, 29 (10): 1338-1341.
doi: 10.7498/aps.29.1338
Abstract +
In this paper, an example is given, through which we have arrived at the following conclusion: the convergence radius of the first order approximate Tc series solutionfor μ*=0 is determined neither by nor by zph=-∫0(ωph)dωg(ω)dω(ω2)/(ωph2-ω2) nor by zph=∫0(ωph)dωg(ω)dω(ω2)/(ωph2+ω2).
1980, 29 (10): 1342-1346.
doi: 10.7498/aps.29.1342
Abstract +
In this paper a procedure is given, which makes use of the anomalous scattering effect in two dimensional reflections to discriminate the two-fold possibilities of atomic positions resulting from the analysis of certain three dimensinal Patterson functions. The procedure has been applied to solve an unknown structure of moderate complexity and proved to be effective.
1980, 29 (10): 1347-1350.
doi: 10.7498/aps.29.1347
Abstract +
Single crystals of 4-Bromowuweizichun B, C23H27O7Br, belong to the space group P212121 with four molecules per unit cell. Since both the Y and Z parameters of the bromine atom are close to 1/4, either the heavy atom method or the Patterson method would lead to a four-fold ambiguity for each light atom. Consequently the structure analysis could not proceed by the usual way. By making use of the method proposed by one of the authors, the ambiguity was easily resolved and the correct structure obtained.
1980, 29 (10): 1351-1354.
doi: 10.7498/aps.29.1351
Abstract +
Using the method of pressing the spring by worm and worm gear, the loading can be made continuous and stable and we can observe the process of phase transition of materials in the high pressure device of diamond anvil. The process of metallization phase transition of iodine and sulphur are observed clearly.
1980, 29 (10): 1355-1356.
doi: 10.7498/aps.29.1355
Abstract +
The electronic states in systems with reconstructed overlayers have been treated by Y. Muda and T. Hanawa. By means of a different method which is very effective for one-dimensional chain problems and through a simpler derivation the same results are obtained.
