Vol. 42, No. 12 (1993)
1993-06-20
GENERAL
1993, 42 (12): 1894-1900.
doi: 10.7498/aps.42.1894
Abstract +
A two-parameter soliton cellular automata is proposed. The algebraic expression of soli-ton velocity and soliton fission condition are given. The interaction behavions of solitons and a number of conservative quantities of the system is well analyzed. A new concept, called ‘essential soliton', is introduced and discussed and the application of the properties of the conservative quantities is exhibited.
ATOMIC AND MOLECULAR PHYSICS
1993, 42 (12): 1901-1909.
doi: 10.7498/aps.42.1901
Abstract +
Based on the relativistic and non-relativistic self-consistent-field methods, we have calculated the oscillator strength density from 3s state to p-channel states for Li-like atomic ions. The dependence of the oscillator strength density on atomic number and some related relativistic effects are discussed. Using the calculated oscillator strength density as interpolation benchmark points, one can easily obtain oscillator strengthes of all 3s-np transitions for Li-like atomic ions (3≤z≤92).
1993, 42 (12): 1910-1913.
doi: 10.7498/aps.42.1910
Abstract +
The C60+ fragmentation caused by electron collision has been studied with a 911A ion source of a mini-separator at the Accelerator Laboratory of Fudan University. The mass spectrum of the fragments has been measured. We found that the fragments contain even number of carbon atoms and the strength of the beam current shows an exponential distribution. Our results show that the fragmentation caused by electron collision has some similarities to that of atomic collision at the energy about 300 keV.
CLASSICAL AREA OF PHENOMENOLOGY
1993, 42 (12): 1914-1918.
doi: 10.7498/aps.42.1914
Abstract +
Reflection and transmission spectra of obligue-incident waves at a kind of general contin-uously-Changeable-dimension fractal cantor Layers are investigated. With the self-similarity, a generalized method and formulae as well as a new type of reflection and transmission spectra, i. e. the self-similar spectra, are abbained. This is a new physical phenomena which would find some application.
1993, 42 (12): 1919-1927.
doi: 10.7498/aps.42.1919
Abstract +
Principle of electron holography and a new method for producing the electrostatio field specimen are presented. Some dielectric particles supported by a thin carbon film, for example, polystarene latex spheres, 0.31 m in diameter, will become a charged body during the observation in electron microscope because of electrostatic accumulation. Obviously, under the electron beam, the spheres of radius r, acquire a stationary positive charge Q and the resulting field can be simply modelled by that of point charge Q. With the field model, the electrostatic field distribution were observed and the sizes of the charged objects are determined by electron holography.
1993, 42 (12): 1928-1932.
doi: 10.7498/aps.42.1928
Abstract +
Both nondegenerate Λ-and V-type laser systems can produce lasers without inversion via optical pumping.
1993, 42 (12): 1933-1937.
doi: 10.7498/aps.42.1933
Abstract +
This paper presents the methods and a part of measurement result about exploration of double exploding foil experiment on inner-shell photoionization X-ray laser scheme. The results show that the line intesities of transitions 3d104p-3d94s2 for Cu-like Pd and Ag ions could be enhanced by the kilovolt pumping X-ray produced in laser-heated NaF and Cu plasmas , but still could not be amplified to form a laser output.
1993, 42 (12): 1938-1941.
doi: 10.7498/aps.42.1938
Abstract +
The characteristics of supercontinuum in various nonlinear materials has been investigated with high-gain, Low-dispersion femtosecond amplifier. The wide-band femtosecond laser supercon-tinuum has been obtained.
1993, 42 (12): 1942-1949.
doi: 10.7498/aps.42.1942
Abstract +
In this paper, we treat optical soliton propagation with quantum method. We derive the quantum nonlinear Schrodinger equation (QNSE) with corrections by using the micro model of a Kerr-like medium and dispersion relation. We also find the perturbation solution of thisequation and study the influence of corrections on squeezing. The result indicates that thethird-order dispersion has no influence on squeezing and the term in ?/(?τ)(φ+φ2) makes theamount of squeezing decrease.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
1993, 42 (12): 1950-1955.
doi: 10.7498/aps.42.1950
Abstract +
A novel type of inclusion—negative crystal in lithium triborate (LBO) crystals,whichis an important new nonlinear optical material,has been observed and investigated by optical microscope,X-ray topography and light scattering topograph. Theirs compositions and nature are made clear and the growth mechanism are also discussed.
1993, 42 (12): 1956-1962.
doi: 10.7498/aps.42.1956
Abstract +
The growth and electrical properties of carbon doped p-type GaAs and InGaAs grown by metal-organic molecular beam epitaxy (MOMBE) using trimethylgallium (TMG), solid arsenic and solid indium as source materials have been studied systematically. The experimental results show that the growth rate and hole concentration of the samples are affected strongly by growth temperature and molecular beam fluxes,especially for InGaAs epilayers. The mechanism of carbon incorporation and its influence on the properties of the samples were also analysed based on the experimental results. It is shown that the changes in growth rate and hole concentration are mainly due to the dependence of TMG decomposition process on the growth condition.
1993, 42 (12): 1963-1957.
doi: 10.7498/aps.42.1963
Abstract +
The fracture behavior of tilt Cu-Bi tricrystals were studied and a contrast with that of Cu-Bi bicrystals was made. The results indicate that the triple junction affected the fracture behaviors of Cu-Bi tricrystals and made a grain boundary exhibit different fracture modes in bicrystal and tricrystal,The high internal stress near triple junction produced incompatibility of plastic deformation, as well as appearing of inhomogeneity of platic glide and lattice rotation. These are discussed by calculating stress field near triple junction.
1993, 42 (12): 1968-1973.
doi: 10.7498/aps.42.1968
Abstract +
A stable hydrogen-terminated Si (100) surface was obtained by using a modified mothed. The Si (100) surface was hydrogen passivated during the ex-situ HF-dip followed by the in-situ low-temperature desorption of physisorbed residues. It was found that this procedure is very effective to eliminate the boron spike at the Si MBE layer/p-Si substrate interface. The origon of the boron spike is also discussed.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
1993, 42 (12): 1974-1978.
doi: 10.7498/aps.42.1974
Abstract +
The ground-state properties of Nb(C1-x□x) have been calculated by using a LDF-LM-TO-ASA supercell method. The calculation was performed by quadruple unit-cell such as Nb4C3□0, Nb4C3□1, Nb4C2□2 ,Nb4C1□3 and Nb4C0□4. The equilibrium lattice constant a(x) , bulkmoduli B(x), Debye temperatures θD(x) and heat of formation h (x) obtained from LM-TO calculation were combined with Bernoull's distribution. These results are in agreement with experimental data.
1993, 42 (12): 1979-1984.
doi: 10.7498/aps.42.1979
Abstract +
We employed the constant photo-conductivity method (CPM) to measure the optical absorption spectra of nano-crystalline siilicon films (nc-Si :H) in the energy range of 0. 9-2. 5eV. We analysed some possible major optical transition processes resulting from the photo-conductivity at different photon energy range and the variation of optical absorption spectra while the films were transformed from amorphous silicon into microcrystalline silicon and then nano- crystalline silicon films. We found that the carriers' optical transition and transport process at the interfaces between grains play an important role in the optical absorption spectra in the whole energy range. We make use of the novel structure of nc-Si:H films to explain our experimental results.
1993, 42 (12): 1985-1989.
doi: 10.7498/aps.42.1985
Abstract +
Based on data of neutron diffraction measurements, the oxidation states in Y1-xPrxBa2Cu3O7-δ system are determined by bond valence sums (BVS) calculation. It is found that a close correlation between the BVS value of Cu(2) and superconducting critical temperature (Tc) exists. We believe that the increase of Pr content leads to the variation of charge distribution when the content of oxygen remains almost constant. At the same time ,the BVS value of Cu(l) and Cu(2) decreases,while that of Y(Pr) increases,and the holes in CuO2 plane are partly localized in Pr-O bond. The quenching of superconductivity by Pr ions is mainly attributed to this localization of the holes in CuO2 plane by Pr ions.
1993, 42 (12): 1990-1997.
doi: 10.7498/aps.42.1990
Abstract +
We present a new approach which is completely based on the permutation group theory to solve the eigenvalue problem of the S = 1/2 Heisenberg finite-chain with free-ends boundary. All of the eigenvalues and the corresponding eigenstates are obtained. The properties of the ground state and the low-lying excited states of the antiferromagnetic chain are examined.
1993, 42 (12): 1998-2004.
doi: 10.7498/aps.42.1998
Abstract +
Formation,structure and magnetic properties of Ho2Fe17Cx compounds prepared by melt-spinning were studied. These carbides are found to be stable at high temperature. Their crystal structure changes from the hexagonal Th2Zn17-type to rhombohedral Th2Zn17-type,as x increases. Saturation magnetization of Ho2Fe17Cx compounds at 1. 5 and 300K were measured, and no dependence of Fe magnetic moment on carbon concentration was found. The introduction of carbon atoms results in the expansion of unit cell volumes and the rising of Curie temperature. According to the molecular field model,we suggest that the rising of Curie temperature with x is mainly due to the enhancement of Fe-Fe exchange interactions by introduction of interstitial carbon atoms.
1993, 42 (12): 2005-2013.
doi: 10.7498/aps.42.2005
Abstract +
The dynamic nonlinear magnetization of different order induced by microwaves in a ferromagnetic material is derived by using perturbation theory. The characteristics of the nonlinear magnetostatic surface wave with wavevector k, making an arbitrary angle to the bias magnetic field, is analysed rigorously. We conclude that the envelope magnetostatic surface solitons in ferromagnetic films can not be generated in all possible direction of propagation.
1993, 42 (12): 2014-2018.
doi: 10.7498/aps.42.2014
Abstract +
The Raman spectra of Pb1-xBaxTiO3(x=0,0. 2,0. 3) have been measured. Experimental results show that there is an obvious effect of small size of crystal in the system.
1993, 42 (12): 2019-2023.
doi: 10.7498/aps.42.2019
Abstract +
In Fraunhofer diffraction of a slit, the slit widths obtained with the fringes produced by polarized light whose vibration is parallel or perpendicular to the slit edge are different. The experimental results about this polarization effect are firstly given. The physical reason of the effect is analysed with boundary diffraction wave. Good coincidence between theory and experiment is achieved.
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
1993, 42 (12): 2024-2031.
doi: 10.7498/aps.42.2024
Abstract +
The chemisorption of CH3NO2 on Cu(111) surface has been studied by the semiempirical quantum mechanical method (CNDO/2) of cluster models. The results indicate that the bridge site of Cu(111) is preferable for CH3NO2 adsorption, the orientation of CH3NO2 adsorption is that -NO2 points downward to the Cu surface, and the angle between the plane ONO and Cu-Cu bond is 60o. The orientation of adsorption and the density of states calculated by CNDO/2 calculation are in agreement with the experimental results. The analyses of atomic orbital percentages show that CH3NO2 adsorption is the result of interaction of 2p atomic orbitals of 0 for CH3NO2 with 3d atomic orbitals of Cu.
GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS
1993, 42 (12): 2032-2038.
doi: 10.7498/aps.42.2032
Abstract +
In this paper, we find out that there is the wormhole solution in the vicinity of vacuum of the Higgs field in induced gravity theory even in the absence of other matter fields.
