Vol. 41, No. 2 (1992)
1992, 41 (2): 177-181. doi: 10.7498/aps.41.177
By applying the theory and method of singular perturbations, we investigate the travelling wave solution of the KdVB equation under the assumption v2?4μ. We get the explicit expression of the travelling wave solution up to the third order atfirst. Then, we obtain the general asymptotic expansion: u=u(0)+εu(1)+ε1u(2)+…+εnu(n)+… and prove that u(j)(j=1,2,…,n,…) are bounded functions.
1992, 41 (2): 182-187. doi: 10.7498/aps.41.182
In this paper, by using the Miura's method, we study the infinite conservation laws of the variable coefficient KdV and MKdV equations with three arbitrary functions of t. The result points out that the conserved densities which have the structures completely similar to the con-stat coefficient KdV and MKdV equations depend only on one arbitrary function. The other two arbitrary functions are contained only in the corresponding fluxes.
1992, 41 (2): 188-192. doi: 10.7498/aps.41.188
The back reaction in Vaidya-Schwarzschild-deSitter spacetime is discussed. It influences location and temperature of both the black-hole event horizon and the cosmological one.
1992, 41 (2): 193-200. doi: 10.7498/aps.41.193
A numerical investigation has been carried out on a RLC series connection which is a two-terminal active network system with nonlinear negative resistance. It is found that within various parameter regions, a sequence of period doubling bifurcations, an inverse sequence of chaotic bands and an intermittant chaos phenomena appeared respectively. These results agree with our experimental ones very well.
THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
1992, 41 (2): 201-212. doi: 10.7498/aps.41.201
We discuss the XXZ spin chain with certain boundary term and the representation of quantum group SUq(2). It is shown that Bethe Ansatz states are highest weight states of SUq(2), with q arbitrary We construct the irreducible representation of the quantum group. For q a rational root of unity, we show that there are new solutions to the BA equations, We derived the state vectors | b′> by taking certain limit, from which we construct the type I and type Ⅱ representations of SUq(2).
ATOMIC AND MOLECULAR PHYSICS
1992, 41 (2): 213-220. doi: 10.7498/aps.41.213
Ab initio study has been used to explore the problem if the Peierls instability in hydrogen chain presents or not. With a Gaussian-type-orbital basis set and periodicity of hydrogen chain, we construct a complete set of orthogonal and normalized wave functions in view of the second-neighbor approximation. Starting from the restricted Hartree-Fock scheme, we diagnoalize the Fock matrix analytically and calculate the LCAO-MO-SCF solutions. The dependence of the total energy on dimerization is analyzed, it is shown that the ground state of metal hydrogen chain is unstable, and that obvious dimerization may occur in infinite hydrogen chain. The Per erls instability presents in this system nevertheless.
1992, 41 (2): 228-232. doi: 10.7498/aps.41.228
The excitation processes in collisions between N6+ and He have been investigated by using the ECR ion source and the LHT-30 VUV Monochromator. The emission spectra shows that there are three channels of excitation in the N6+ and He collision system: (1) Single-electron capture into excited states. (2) Double-electron capture into excited states. (3) Direct excitation of indicident ions.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
PEIERLS MECHANISM OF HYDROGEN CHAIN (Ⅱ)——THE DEPENDENCE OF THE PEIERLS INSTABILITY ON THE ELECTRON CORRELATION
1992, 41 (2): 221-227. doi: 10.7498/aps.41.221
We use the correlated basis functions method to explore the problem of the Pe-ierls instability due to the electron correlation in hydrogen chain. Our thory shows that the bond alternation is reduced from 0.37 (au) to 0.32 (au) by the electron correlation, but the Peierls instability survives under the electron-electron interaction.
1992, 41 (2): 302-305. doi: 10.7498/aps.41.302
The thermal stability of a-Si:H/a-Ge:H superlattices was studied using LR and XRD spec tra. It was found that the crystallization temperature of superlattices with small layer thickness is higher than that of bulk a-Ge:H. Results are discussed preliminarily.
1992, 41 (2): 306-310. doi: 10.7498/aps.41.306
Based on X-ray dynamical theory, the double-crystal diffraction rocking curves for In-GaAs/InP single layer and InGaAs/AlInAs/InP superlattice were calculated for both perfect and rough interfaces. It is shown that the effect of roughness of multilayer interface on the zero-order diffraction peak was not obvious but severe on both the satellite peaks for superlattice and the interference fringes for single layer structure. With the increasing of the interface roughness, the intensities of interference fringes were reduced and disappeared. And for the satellite peaks, their intensities were reduced and the full width at half maximum broadened. Comparing the experimental result with the calculated one, we believe that there still exists an average roughness of about one monoatomic layer at the interface of high quality InGaAs/Al-InAs/InP lattice-match superlattice sample.
ALTERNATING CURRENT SUSCEPTIBILITY STUDIES OF Y-Ba-Cu-O (123) BULK MATERIAL PREPARED BY MELT-TEXTURED GROWTH METHOD
1992, 41 (2): 311-316. doi: 10.7498/aps.41.311
The a.c. susceptibility of Y-Ba-Cu-O(123) bulk material prepared by melt-textured growth (MTG) method was studied and compared with that of sintered sample in this paper. The results show that there are two peaks in the imaginary part corresponding to the grains and grain boundaries in the sintered sample, but only one peak is observed in that of MTG sample of high quality. As for that of MTG sample of worse quality, also two peaks are observed, but they correspond to grains with different growth direction. No frequency effect is observed in both the sintered sample and the MTG sample, showing that the loss is related to flux motion.
1992, 41 (2): 317-322. doi: 10.7498/aps.41.317
Anisotropic critical current densities of melt textured YBa2Cu3O7-y superconductor were measured using d.c. magnetization measurements. Effcet of demagnetizing field was taken into account. A model appropriate to finite anisorropic samples was adopted and the method proposed recently by Gyorgy et al. was modified. We measured magnetization curves of a rectangular parallelepiped sample in magnetic fields parallel to different edges of the sample and obtained values of three different critical current densities.
1992, 41 (2): 323-328. doi: 10.7498/aps.41.323
From Zou and Anderson's spinon-bolon effective Hamiltonian, for very large Coulomb repulsion U, we consider the problem of ferromagnetism on the square lattice by studying the fluctuation effect of bosons (holons).
1992, 41 (2): 329-332. doi: 10.7498/aps.41.329
The x-ray and γ-ray radiolytic damage in luminous host material BaCl2 and its recovery have been studied by the electron spin resonance method. It is found that the x-ray radiolytic damage in the sample can be recovered completely under sunlight for only two minutes, but the complete recovery of γ-ray damage is not easy.
1992, 41 (2): 333-341. doi: 10.7498/aps.41.333
According to first-order capture equation, a kinetic theory for trap creation in solid dielectrics is proposed in this paper. Taking a certain trap density as critical condition of electrical breakdown, it is found that the dielectrical lifetime is proportional to the exponent of electrical strength. Such a theory is consistent with the widely used emperical formula and agrees with experimental results.
1992, 41 (2): 342-346. doi: 10.7498/aps.41.342
Two laser beams of wave length 632.8nm encouter in Mn doped KNSBN crystal and induce a optical diode. A maximum ratio of 202 for equivalent transmissivity in two directions of the optical diode is obtained at the input powers of 0.876mW and 0.0914mW respectivly and the ratio shows a tendency to increase further.
CLASSICAL AREA OF PHENOMENOLOGY
1992, 41 (2): 238-243. doi: 10.7498/aps.41.238
In this paper we derive the time-space correlation funotion of dynamic speckles produced by double light beams. An experiment using photon correlation method is performed, the result accords well with the expectation of the present theory.
REFLECTION AND TRANSMISSION OF PICOSECOND SOLI-TON AT INTERFACE SEPARATING TWO MEDIA IN OPTICAL FIBER
1992, 41 (2): 244-252. doi: 10.7498/aps.41.244
The governing equations and boundary conditions for reflection and transmission of picosecond soliton at the interface between two media in optical fiber is developed by radial mode averaging method with slowly varing envelope and quasi-monochromatic approximations. The proccess of reflection and transmission is numerically simulated by using beam-propagating method and some numerical examples are given.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
1992, 41 (2): 253-259. doi: 10.7498/aps.41.253
Using a simple model, it is shown that because of the relativistic electron-mass variation, the mode-converted electrostatic electric field exhibits hysteresis in the vicinity of critical layer. This hysteretic effect is to increase the resonance absorption of obliquely incident p-pola-rized light in a way by increasing the large amplitude region of the electrostatic field. When the threshold light intensity for the occurance of hysteresis is exceeded, the fractional absorption increases drastically above the linear results.
THEORY OF DEGENERATE AND NEARLY DEGENERATE FOUR-WAVE MIXING IN PLASMAS——IN THE CASE OF REFLECTION GRATING CONFIGURATION
1992, 41 (2): 260-266. doi: 10.7498/aps.41.260
In this paper, the theory of degenerate and nearly degenerate four wave mixing in plasmas in reflection geometry is investigate. The universal set of four wave nonlinear coupled equations is obtained and its exact solution appropriate for arbitrary nonlinear coupling parameter is found.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
1992, 41 (2): 267-271. doi: 10.7498/aps.41.267
X-ray diffraction from uniformly bent Si crystal has been studied. The experimental integrated diffraction intensity rises monotonically with the strain in the crystal, this coincides with the theory. The visibility of Pendell?sung fringes becomes poorer as the strain goes up, this reflects the increse of intensity difference between the wave fields and variation of the trace of the wave fields in the crystal.
1992, 41 (2): 272-275. doi: 10.7498/aps.41.272
Dislocations in a new non-linear crystal, Lithium Boric Oxide(LBO), have been observed and identified by X-ray diffraction topography. The structural factor which plays important role on dislocations formation, the lattice expansion and twinned growth is given.
1992, 41 (2): 276-281. doi: 10.7498/aps.41.276
Diamond-like carbon (DLC) films, prepared by dual-ion beam sputtering method on glass substrate, were irradiated by high energy hydrogen ions(H+) under different combinations of ion energy and irradiation dose. Raman spectroscopy, infra-red transmittance spectroscopy, electrical resistivity measurement and adhesive force determination were used to characterize the as-deposited and the irradiated films. The results showed that, comparing with that of as-deposited ones, the properties and structures of irradiated films were changed obviously: the infra-red transmittance in the range of 1450 to 6000 cm-1 was increased; the electrical resistivity had nearly no large change. The relative ratios of sp2 C-H bond to sp3 C-H bond and sp3 C-C bond to sp2 C-C bond were also increased, while the component of sp3 C-C bond and sp2 C-C bond was decreased because of H+ irradiation. On the basis of the above results., the relations between properties and structures for irradiation On the basis of the above results, the relations between properties and structures for irradiated films were discussed in detail between properties and structures for irradiated films were discussed in detail. It is concluded It is concluded that the H+ irradiation effect on DLC films is different from that of Cc or other heavier ions. The main role of H+ on the films is the teching effect on weaker bonds. We believe that it is possible to improve the properties of DLC films by means of high energy H+ irradiation.
FORMATION OF HOLOGRAPHIC DIFFRACTION GRATINGS ON THE SURFACE OF A n-TYPE Ga As AND MEASURING OF LIGHT EMISSION BY SURFACE PLASMON POLARITON
1992, 41 (2): 282-287. doi: 10.7498/aps.41.282
The method to produce diffraction gratings by H2O2-H2SO4 photo-accelerated etching on the surface of n-GaAs and measuring of light emission by surface pla smon polariton from an Ag/n-GaAs Schottky barrier diode are discussed in this paper.
A STUDY ON THE 2% PdO/Al2O3 BY MEANS OF FREE POSITRON ANNIHILATION TECHNIQUE IN THE SOLID SURFACE LAYER
1992, 41 (2): 288-294. doi: 10.7498/aps.41.288
In this work, we studied the relationship between heat treatment and space structure of the PdO layer in 2% PdO/AL2O3 by the positrons from 22Na radiative source, and calculated its grain size by the positron annihilation parameters, demonstrating that the free positron annihilation technique for the solid surface layer can be applied to catalyst research.
1992, 41 (2): 295-301. doi: 10.7498/aps.41.295
An ASED-MO method has been applied to investigate the N2 chemisorption on Cr(110) surface. The results show that N2 chemisorbs parallelly on the 4-fold site with N-N axis parallel to  direction. Different from the tranditional σ-donation and π weak backbonding concepts, the N2 chemisorption on Cr(110) has both the 3 σg and 1 πμ donations of 0.97 and 0.54 electrons. At the same time, the backbonding to the 1 πg orbital increases to 1.83 electrons. Both these factors make the lying-down orientation being favored over the upright orientation. Furthermore, the N-N bond length strenches 17%, the N-N bond order decreases to below 1, and the dissociation barrier is only about 0.15 eV. All the above calculation results are in good agreement with relevant experiments.
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
1992, 41 (2): 347-352. doi: 10.7498/aps.41.347
The ESR single and magnetic properties of free standing film of polyaniline (PANI) have been measured as a function of elongation treatment and the protonation state. The results obtained are compared with its powder. The magnetic properties of free standing film of PANI is similar to its powder, and it varies with transition of insulator to metal after protonation. For elongated free standing film of PANI, on the other hand,both Pauli and Curie spin are higher than that of its powder and the free standing film this may be due to increasing of interaction between uncoupled electrons on quinoid ring at PANI chain.