Vol. 41, No. 5 (1992)
1992-03-05
GENERAL
1992, 41 (5): 697-703.
doi: 10.7498/aps.41.697
Abstract +
When a quantum system with continuous spectrum has a definite anergy, ordinary quantum mechanics uses a single continuous stationary state to describe its properties, the expectation values for arbitrary physical quantities are therefore either infinity or zero. In this paper we point out in the form of mathematical theorem that the system possesses new and deterministic results with evident physical meanings. Classical results for the system are the classical limit cases of these results, and the ordinarv expectation values are the statistical cases of our results.
1992, 41 (5): 704-709.
doi: 10.7498/aps.41.704
Abstract +
It is shown analytically as well as numerically that a periodic window of the coupled map system exists only for very weak coupling strength (about 10-3 for period 3 window, for instance), which could be defined as the depth of the window. Within the windows the behavior of the coupled map system could be recovered by dealing with a few number of modes, which consist of coupled three maps. The first Lyapunov exponent for the coupled map system shows a "zigzag" curve form virsus the coupling strength.
THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
1992, 41 (5): 710-719.
doi: 10.7498/aps.41.710
Abstract +
We have derived the generalized Noether's first theorem in canonical formalism for field theory with singular Lagrangian and generalized Noether's identities in canonical formalism for variant Lagrangian. The application to the Dirac's constraint theory was discussed. We point out that some variance system may has a Dirac constraint. A counter-example to a conjecture of Dirac was given which indicates that Dirac's conjecture is invalid in this example. The application of generalized Noether's identities to the chromodynamics is also discussed.
NUCLEAR PHYSICS
1992, 41 (5): 720-725.
doi: 10.7498/aps.41.720
Abstract +
Assuming that the 11Li, 14Be and 17B nuclei are composed of the core and two outer neutrons, we have investigated the giant dipole mode of these nuclei by sum rule approach. The excitation energy and the strength of the soft dipole mode are calculated and compared with other theoretical results.
ATOMIC AND MOLECULAR PHYSICS
1992, 41 (5): 726-731.
doi: 10.7498/aps.41.726
Abstract +
In this paper, by using extended average level (MCDF-EAL) model of relativistic multi-configuration Dirac-Fock code, we have calculated 44 fine-structure energy levels of 2s2p3,2s2p4,2p5,2s22p23s,2s22p23p configurations and 24 transition wavelength of 3s-3p configuration of N-like KXIII; CaXIV, ScXVVV and TiXVI ions which may be the candidates for lasing acton. The calculated values of 3s, 3p configuration of KXIII, CaXIV and ScXV are our present results.
1992, 41 (5): 732-739.
doi: 10.7498/aps.41.732
Abstract +
The autoionization spectra of Yb have been observed and studied by three-step Laser excitation. Sixteen autoionization levels of Yb in the energy range from 50443 cm-1 to 57750 cm-1 have been investigated. The total angular momentums J of two autoionization levels were determined by a polarization technique.
1992, 41 (5): 740-743.
doi: 10.7498/aps.41.740
Abstract +
Excited by Ar+ laser lines of 457.9, 476.5,496.5, 514.5nm, the 650-760nm diffuse emission of A2Π-X2Σ lor Van der Waal's molecular LiAr has been observed in a lithium heat-pipe oven with Ar gas. The dynamics of this emission is discussed.
1992, 41 (5): 744-749.
doi: 10.7498/aps.41.744
Abstract +
The electron impact ionization cross sections for different energy assignment on two final-state electrons (energy differential cross sections) of heliumlike ions have been calculated by using a disrored-wave Born exchange approximation. We found that the dependence of the differential cross sections on the scaled energy of secondary electrons can be well fitted with a two-parameter Gaussian function. The dependence cf two parameters on the incident electron energy and target charges have been given. The differences between the results from CBE (Coulomb-Born exchange approximation) and DBE calculations have been discussed. They show that it is necessary to use DBE calculation for low target charges and low incident en-
CLASSICAL AREA OF PHENOMENOLOGY
1992, 41 (5): 750-758.
doi: 10.7498/aps.41.750
Abstract +
The theory and approach of the eigenvalue problems of the imaging integral operator of finite domain are discussed in detail. The approximation solution of the imaging integral operator equation is derived by expanding the eigenfunctions in the space of the zeroth-order eigenfunctions. The eigenvalues and eigenfunctions for real microscopic objectives with symmetric aberrations are calculated in terms of the measured LSF data. The experimental system is described and the results are discussed.
1992, 41 (5): 759-765.
doi: 10.7498/aps.41.759
Abstract +
The optical parameter distribution can be determined when the polarization state and phase difference of the object wave and reference wave are given. Thus, the polarization hologram can be regarded as a complex polarizing element. According to the matrix theory of the polarizing element, the transmission matrix of polarization holograms can be found. The Jones vectors of the reconstructing wave can be found by the product of the Jones vectors of the illumination light and the transmission matrix of polarization holograms.
1992, 41 (5): 766-773.
doi: 10.7498/aps.41.766
Abstract +
In this paper, we have respectively investigated the time evolution of the phase operator of radiation field in the Jaynes-Cummings model with and without RWA. We verified that the atomic Rabi oscillation leads to the phase dissipation of radiation field by analytical method, and the effect of virtual field can exhibit the quantum fluctuations of system and leads to the frequency shift of radiation field.
1992, 41 (5): 774-782.
doi: 10.7498/aps.41.774
Abstract +
Tn this paper, we have obtained the power expression of the coherent harmonic emission generated by the fundamental mode bunching, and explained their temporal profile and line-width.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
1992, 41 (5): 783-791.
doi: 10.7498/aps.41.783
Abstract +
Explosive mode coupling of low frequency interchange instability in partially ionized plasmas is studied. The coupled equations describing coherent wave-wave interactions of the interchange mode are derived. The possibilities of explosive instabilities for the interchange mode are found. It is shown that there exist the explosive coupling of positive energy wave and negative energy wave, positive energy wave and negative dissipation, and negative energy wave and positive dissipation, in the partially ionized plasmas. The theoretical results obtained can be applied to the ionospheric plasma and the mirror-confined plasma.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
1992, 41 (5): 792-797.
doi: 10.7498/aps.41.792
Abstract +
This paper analyses the atomic correlations in crystalline and amorphous Si and Ge and discusses their relationship. Expressions for the atomic correlations are presented. On the basis of the theory, a 400-atom structural model for a-Ge has been constructed. The main characteristics of the model are in good agreement with experimental results.
PHYSICAL MECHANISM OF SYNTHESIZED DIAMOND FILMS ON THE SUBSTRATE OF A STRONG CARBIDE FORMING ELEMENT
1992, 41 (5): 798-803.
doi: 10.7498/aps.41.798
Abstract +
It has been discovered that the physical process of diamond surface metallization is the converse physical process of synthesized diamond film produced by plasma CVD when the substrate is strong carbide forming element and synthesitic temperatures range from 700℃ to 1000℃. We predicted that the physical process of synthesized diamond film should have a structure such as W-WC-diamond film or Si-SiC-diamond film, etc. under this condition.
1992, 41 (5): 804-808.
doi: 10.7498/aps.41.804
Abstract +
The long-range topological disorder of a screw dislocation provides a peculiar medium for waves in solids. Influences of potential in this medium to electronic states are investigated. A square well potential is employed as a simple example. The potential scattering solution in this medium is successfully obtained in terms of the phase-shift analysis. The unperturbed wave function is not the plane wave but the exact solution of the Aharonov-Bohm equation. The number and position of the bound state levels depend on the coupling of an electron and the topological disorder.
1992, 41 (5): 809-813.
doi: 10.7498/aps.41.809
Abstract +
In this paper, the secondary defects and their annealing behaviours in Zn+, Mg+, Be+ ion-implanted InSb have been investigated by means of the plan-view transmission electron microscopy (TEM), cross-sectional TEM(XTEM) and Rutherford backscattering and channeling spectroscopy. The result shows that the secondary defects caused by the lighter Be+ ion implantation are much less than that caused by the heavier Zn+ ion implantation. And the ion Mg+, in the region of medium dose (about 1×1031cm2), causes the damage easy to restore. The effect of annealing temperature is investigated from 360℃ to 440℃, and the result indicates that the 360℃ is a better annealing temperature. The figuration of secondary defects in ion-implanted InSb is differant from that in ion-implanted Si: the secondary defects in ion-implanted InSb consist of dislocations and dislocation networks mainly, and the dislocation loop is not dominant, however, precipitates and fault tetrahedras also exist in it.
1992, 41 (5): 814-818.
doi: 10.7498/aps.41.814
Abstract +
Dynamic mechanical loss spectra correspornding to different frequency were measured at ascending temperature for amorphous polymer PVC (a-PVC). It is found that measuring frequency dependance of the parameters of a-peak obviously exists. To determine the contribution of τ0 or ΔH distribution to τ distribution, on the basis of analysing relaxation time distribution (τ distribution) of α-peak in a-PVC, the parameters of τ0 and ΔH have been calculated in this paper.
1992, 41 (5): 819-826.
doi: 10.7498/aps.41.819
Abstract +
In this paper, we investigate the method of kinematic low energy electron diffraction (KLEED) and constant momentum transfer averaging (CMTA). Through a thorough review, we point out that the method has great potential in surface structure determination although it had not been used properly in che past years. This method has been improved greatly in the present work. Firstly, with our own experiment, we demonstrate that the effect of multiple scattering can be eliminated in large part by averaging only a few I-S curves taken with different suitably selected diffraction geometry. Secondly, we show that in KLEED calculation, the constant scattering factor approximation is quite convenient and reasonable for surfaces consisting of same kind of atoms. Thirdly, this work introduces a peak broadening factor to reflect the thermal effect upon the I-V curves which had been neglected in some KLEED calculations. Finally, nonstructural parameters, such as inner potential, mean free path, peak broadening factor and attenuation factor, are optimized to give the best agreement between the calculated and experiment results. Application on Cu(001)1×1 surface indicates that the improved KLEED/CMTA method for surface analyses is simple, reliable and powerful.
1992, 41 (5): 827-832.
doi: 10.7498/aps.41.827
Abstract +
In this paper, we carried out an improved kinematic low energy electron diffraction and constant momentum transfer averaging (KLEED/CMTA) analysis of aSi(111)31/2×31/2-Al structure After a thorough optimization of the parameters, we came to the conclusion that T4 model is the best, which gives an excellent agreement with experiment curves(RVHT = 0.158). Atomic coordinates and bond lengths of the model have been determined for Al atoms and all Si atoms in the first six layers of the substrate. None of the bond-length deviations from the bulk value is larger than 5% and within an error bar of 0.05A, all of the parameters (except a lateral displacement) are consistent with the conclusion of DLEED. The successful application of the KLEED/CMTA method to such a complicated surface structure indicates strongly that the method is really very poweriul and reliable,and thus has great potential in surface structure analysis.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
1992, 41 (5): 833-840.
doi: 10.7498/aps.41.833
Abstract +
In this paper the electrical conductance of a two-phase composite medium with ellipsoidal inclusions has been investigated by using the effective-medium theory(EMT). An anisotropic factor m is suggusted TO take account of the local anisotropy of an inhomogeneous system. A formula for calculating the effective electrical conductivity tensor in such case has been proposed. A geometrical structure factor Ii(i = x,y,z) is introduced to estimate the near field effect between the particles aggregated in the inclusions. It has been shown that there is a simple relation between the structure factor Ii and the depolarization factor ni. The calculated results based on the EMT show that prolate ellipsoid (b/a = 0.2) and oblate ellipsoid (b/a=7.5) are the two principle geometrical configurations leading to the percolation threshold c1* =0.17. A preliminary theoretical analysis informs that the common mechanism leading to the percolation by these two configurations is the formation of an 'infinite' chain-shaped cluster.
1992, 41 (5): 841-845.
doi: 10.7498/aps.41.841
Abstract +
No-resonant microwave absorption signals in BiPI SbSrCaCuO samples with different si zes and in coarse vacuum were measured, the experiment showed that the signals related to the grain size of the sample and oxygen atmosphere. The signal intensity was proportional to the Meissner state volume which was a shell layer of the skin effeet in the penetration layer.
1992, 41 (5): 846-850.
doi: 10.7498/aps.41.846
Abstract +
Effect of slow neutron irradiation of low fluence on bismuth-based superconductors is studied. It's shown through experiments that (1) both critical current density Jc and zero-resistance temperature Tc0 are increased, though to different extents, after the Bi-based superconductors were irradiated with slow neutrons to suitable fluence and (2) slow neutrons of low fluence and fast neutrons of high fluence have similar irradiation effects on Bi-based superconductors.
1992, 41 (5): 851-860.
doi: 10.7498/aps.41.851
Abstract +
A series of F-doped rare-earth superconductors RBa2Cu3OxFx were synthesized with CuF2 as one of the reactants. According to comparative experiments. It was found that sintering temperature was lowered, transition width was narrowed, the zero resistance temperature was raised to some degree, and lattice parameters was changed, as the oxygen was substituted by fluorine. It was proved that the fluorine had entered into 123 supercoductive phase lattice. The effect of fluorine on superconductivity was also discussed.
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
1992, 41 (5): 861-868.
doi: 10.7498/aps.41.861
Abstract +
Directional solidification of lamellar eutectic has been studied both theoretically and experimentally. This process has been modeled through comparing it with directional solidification of an array of cells in binary alloys and developing of the Saffman-Taylor viscous fin-gerinig in a Hele-Shaw cell in an unitied framework. A coupling relation among the solute diffusion, the thermal transfer and the capillary effect of the growing interface has been derived. The well known scaling law λ2V = const can be derived from this relation. Directional solidification of regular Al-Al2Cu eutectic and irregular Al-Si eutectic has been investigated experimentally, the coupling relation has been verified. The solidifying interface profile and thermal transfer effect of solidification have also been discussed.
