Vol. 48, No. 3 (1999)
1999, 48 (3): 385-388. doi: 10.7498/aps.48.385
The general formulas for radial matrix elements p|n′l′> and q|n′m′> of three-dimensional and two-dimensional isotropic harmonic oscillators are derived-
1999, 48 (3): 389-394. doi: 10.7498/aps.48.389
Three kinds of characteristic surfaces of the charged axially nonstationary black hole are studied,namely,the event horizon,the apparent horizon and the time-like limit surface-The new results are shown when mass and charge of the black hole vary-
1999, 48 (3): 395-401. doi: 10.7498/aps.48.395
By using of the brick-wall method,we calculate the free energy and the entropy of Dirac spinor field in Schwarzschild black hole-It shows that the entropy of Dirac field is proportional to the area of black hole horizon and the entropy of Dirac field is 7/2 times that of Klein-Gordon field-
1999, 48 (3): 402-407. doi: 10.7498/aps.48.402
A new method is used to control chaos and hyperchaos in nonlinear system by phase space compression-As examples,the Henon map and Lorenz system as well as Rossler hyperchaotic system are researched numberically- The results show that the behavior of chaos and hyperchaos in the nonlinear system can be controlled effectivelly by phase space compression and 98P high periodic stable orbits can be obtained-
BIFURCATION AND OPTICAL BISTABILITY OF LASER-LORENZ EQUATIONS INDUCED BY A PUMP PARAMETER SLOWLY VARYING WITH TIME
1999, 48 (3): 408-415. doi: 10.7498/aps.48.408
In this paper,a new and simple method is presented for studying the semi-classical Laser-Lorenz equations with an injected signal-The pump parameter varies slowly with time,thus it induces delayed bifurcation and transient optical bistability-By scale balancing and approximating to the slowly-varying solution by that of the linearilized system, a scaling transition relation and a condition for transient optical bistability are given-The intervals of values of bifurcation and transition,and hysteresis loops of the transient optical bistability are given by numerical analysis-
A NEW WAY FOR MEASURING INTERDIFFUSION COEFFICIENT OF LIQUID METAL——SOLID/LIQUID-LIQUID/SOLID TRILAYER SYSTEM
1999, 48 (3): 416-420. doi: 10.7498/aps.48.416
A new way for the study of diffusion processes in liquid metals in solid/liquid-liquid/solid trilayer systems is proposed-The design of this kind of trilayers enables diffusion processes to take place,without effect of gravity-induced convection and Marangoni-convection-The Ta/Zn-Sn/Si trilayers were selected as an example and the interdiffusion of liquid zinc and tin at 500℃ was investigated-
STUDY ON THE PRINCIPLE OF THE VISCOSITY MEASUREMENT OF LIQUIDS WITH A FORCED-VIBRATION TORSION PENDULUM
1999, 48 (3): 421-425. doi: 10.7498/aps.48.421
The principle of the viscosity measurement of liquids with a forced vibration torsion pendulum is studied in this paper-The parameters of the testing system was determined by a 3-parameter model containing a Voigt unit,and the feasibility of the corresponding 4-parameter model of the measuring system,in which a liquid sample has been introduced to measure its viscosity,is then verified-It is proposed,based on the experimental results,that the measuring system is reliable-
1999, 48 (3): 426-432. doi: 10.7498/aps.48.426
The angular momentum projection shell model is applied to the nucleus 129La- The results of theoretical calculations about the one-quasiproton bands are compared with experiment data,the agreement with the yrast πh11/2 band and the πg7/2 band is satisfactory- We also assign the πg7/2［νh11/2］2 configuration with an oblate shape for one of the bands of 129La-
1999, 48 (3): 433-437. doi: 10.7498/aps.48.433
The yrast bands of odd-odd nuclei in A=80 region are calculated by using the axial rotor plus two quasipaticles model- The results coincide with the experimental data and the point of signature inversion is reproduced accurately-
ATOMIC AND MOLECULAR PHYSICS
1999, 48 (3): 438-445. doi: 10.7498/aps.48.438
Dynamical symmetry group for highly excited vibrational spectra of triatomic molecules has been studied-The results showed that the dynamicsl symmetry of tiratomic molecules are U1(4)U2(4)-Therefore,the Hamiltonian of triatomic molecules can be writen as the sum of elements of Lie algebra U1(4)U2(4)- And the eigenvalue of molecular Hamiltonian can be obtained by Lie algebraic treatment-
STUDY ON THE TWO-PHOTON RESONACE-ENHANCED MULTIPHOTON IONIZATION OF CF RADICALS: DETERMINATION AND ANALYSIS OF 5p RYDBERG STATE
1999, 48 (3): 446-452. doi: 10.7498/aps.48.446
In this paper,(2+1) resonance-enhanced multiphoton ionization(REMPI) spectra of CF radical between 260—360nm have been investigated- CF radicals were produced by a pulsed dc discharge in the mixtures of Ar/CF4,Ar/CF2Cl2 or Ar/CF3COOH-A new vibrational progression of 5p Rydberg state with band origin of 67746cm-1 were observed between 260—305nm-The vibrational frequency ω′=1848cm-1,inharmonic constant ωe χe′=18-5cm-1 and the quantum defect δ=0-625 have been determined by the assigned REMPI spectra- Furthermore,the (2+1)REMPI spectra of CF radical between 310—360nm,were also observed and assigned as 3p(v′=2—6) resonant excitation- The related spectroscopic constants have been derived-
1999, 48 (3): 453-460. doi: 10.7498/aps.48.453
Based on the modified three-body Sommerfeld parameters,the effective shield of the residual electron in the final state of He+ is further modified for (e,2e) processes- Such a modification represents a dynamic screening of the four bodies in the final state- The triple differential cross sections for electron impact ionization of atomic helium at an incident energy of 50eV in the asymmetric geometry are calculated by use of the modified Sommerfeld parameters-The results were compared with those of the absolute measurements and the only existing theoretical results of the convergent colse-coupling method-It was found that the present results give a better description for the experimental data at fixed ejected energy of 10eV-
CLASSICAL AREA OF PHENOMENOLOGY
1999, 48 (3): 461-467. doi: 10.7498/aps.48.461
Using Bergman representation theory,we derived the first principle formulation of electric potential of binary composites,and calculated the electric potential distributions for bct,fcc and bcc structures-
1999, 48 (3): 468-473. doi: 10.7498/aps.48.468
Based on the Bloch-Maxwell equation,the three-dimensional model for the double-pulse propagation in a two-level system was set up-The propagation of the double pulses with different areas has been described and compared to that of the single pulse-The pulse mergence has been found in the double-pulse propagation-
INFLUENCE OF PHOTOSENSITIZER IN LOW GLASS TRANSITION TEMPERATURE PHOTOREFRACTIVE POLYMERIC COMPOSITE
1999, 48 (3): 474-479. doi: 10.7498/aps.48.474
The two-beam coupling gain and phase-shift were measured in the low glass transition temperature photorefractive composites of poly(N-Vinylcarbazole) doped with plasticizer N-ethylcarbazole,electro-optic chromophore 2,5-dimethyl-4-(p-nitrophenylazo) anisole and various contents of photosensitizer fullerene C60-The influence of photosensitizer on the photorefractive behavior was studied-
Making use of the method of multiple scales from the classical perturbation theory and the general method of Laplace transformation from the mathematical physics methods, we have solved the perturbation problem for sine-Gordon equation, and obtained the fist-order correction containing no secular terms, as well as the parameters slowly varied with time-
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
1999, 48 (3): 485-490. doi: 10.7498/aps.48.485
The shock-compression properties of liquid deuterium and hydrogen are studied by means of the variational fluid perturbation theory- The present theoretical results are in excellent agreement with RRY theory and Nellis'experimental data- The present calculation for the shock temperatures are higher than Holmes' experimental data, the reason for the apparent agreement of the pressures and for the higher shock tempratures are explained-
1999, 48 (3): 491-496. doi: 10.7498/aps.48.491
Metallic nanoparticles complex thin film is a new kind of promising photoemissive thin film because of its perfect photoemissive properties and extremely fast optical response- We obtained a light-emitting Ag-BaO nanometer thin film using vacuum deposition method- Red-blue-violet range light emission was observed from its photolumine-scence(PL)- We believe that the origin of PL of Ag-BaO thin film is the contribution of the Ag nanoparticles- Compared with its ultraviolet-visible absorption spectra, the mechanism of its PL covering different visible light ranges was analyzed-
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
The electronic dynamics of an incommensurate system have been studied with site potentials Vn=λtanh［Acos(2πσn)］/tahnA, where σ=(5-1)/2. By analyzing the wave function, we find the extended eigenstates are similar to the Bloch waves, and critical states occur in some Hamiltonian parameter regions. Much attention is paid to the long-time behavior of the autocorrelation function C(t) and mean square displacement d(t). When all states in the system become extended, C(t)～t-1 and d(t)～t1. In the regime with absolute localized states, C(t)～t0 and d(t)～t0. Between these two extremes, there exists a complex phase regime in which extended states, critical states and localized states coexist, and the behavior of C(t) is related to the initial site, but with d(t)～t1. Moreover, the relation between C(t) and the local spectral probability R(l) have been studied.
1999, 48 (3): 505-510. doi: 10.7498/aps.48.505
The temperature dependence of resistance in the La2/3Ca1/3Mn1-xCuxO3(x=0 and 0.15) system at temperatures much lower than Curie temperature has been experimentally studied. It is found that a resistance minimum obviously appears in the zero-field R-T curve of the Cu-doped sample. Such a resistance minimum disappears when a magnetic field is applied to the sample. Based on Kondo theory, a quantitative comparison between the theory and the experimental data has been presented. It is shown that the experimental observation can be well understood within the framework of Kondo theory.
1999, 48 (3): 511-519. doi: 10.7498/aps.48.511
Taking into account the quantum size effects and considering three types of scattering from bulk impurities,rough surfaces and rough interfaces, we use the quantum-statistical Greens function approach and Kubo theory to calculate the giant magnetoresistance (GMR) in magnetic multilayered structures.Our calculations can reproduce the main features of GMR experiment, including the oscillations of GMR with nonmagnetic thickness, and the GMR increases with increasing number of bilayer N of the (Fe/Cr)N/Fe system.Moreover,whether or not additive are the parts of scattering from the impurities, surfaces and interfaces is also discussed.
1999, 48 (3): 520-526. doi: 10.7498/aps.48.520
The melt spun ribbons of nanocomposite Nd9Fe85.5-xCoxNb1B4.5(x＝0-16) have been prepared by rapid quenching and post heat treatment. The best magnetic properties obtained in Nd9Fe84.5Nb1B4.5 ribbons are as follows:(BH)max＝156kJ/m3,Jr＝1.11T and μ0HcJ＝0.68T.It is shown that the melt spun ribbons consist of both 2∶14∶1 compound and α-Fe(Co,Nb) phases with mean grain sizes smaller than 30nm. The effect of exchange coupling between the nanostructure grains of Nd2(Fe,Co,Nb)14B and α-Fe(Co,Nb) are observed clearly. The Curie temperature enhancement is about 10K and the largest reduced remanence achieved 0.776.It is also indicated that there is a close relation between the reduced remanence and the mean grain size of α-Fe phase. The smaller the mean grain size of α-Fe phase, the greater the remanence enhancement. The Curie temperature of the melt spun ribbons increases quickly with a rate of 11.3K/at%. The coercivity, remanence and maximum energy product decrease monotonically with increasing Co content for the Nd9Fe85.5-xCoxNb1B4.5 ribbons.
1999, 48 (3): 527-532. doi: 10.7498/aps.48.527
When the fraction of inordinate component on the interface or/and surface in nanostructured FeAl is comparable to that of crystal grain which is wrapped up in the former,and there exists Fe-Al-Fe surperexchange or/and Fe-Fe exchange interactions in the inordinate component on the interface or/and surface, a nonmagnetism—magnetism transition between polycrystall FeAl alloy and nanostructured FeAl would result.There was no signal of magnetic resonance in the bulk polycrystal FeAl from the experimental results of electron spin resonance (ESR) in X wave band with a frequancy of 9.48GHz.The ferromagnetic resonance (FMR) signals were observed in the nanostructured samples, whose line widths ΔHpp were over 8×104A/m.Otherwise,an ESR fine structural signal of double peaks of Fe2+ ion was also observed in nanocrystal line samples, the interval of the two peaks was 1.316×105A/m,and the ΔHpp of each peak was smaller than 800A/m.The configuration of the paramagnetic Fe2+ was 3d54s1, and spin quantum number was S＝1,its zero-field splitting D was 2.448GHz,or 10.12×10-6eV.An overlap of the ESR double peaks of paramagnetic Fe2+ and the wide FMR peak resulted in two sharp peaks like resonant singularities on the FMR spectrum.
MONTE CARLO SIMULATION ON ELECTRON INTERVALLEY TRANSFER PROCESS IN ZnS-TYPE THIN-FILM ELECTROLUMINESCENT DEVICES
1999, 48 (3): 533-538. doi: 10.7498/aps.48.533
Based on the calculation about intervalley scattering rates in ZnS, intervalley transfer process in ZnS-type thin-film electroluminescent devices is investigated through Monte Carlo simulation. The transient process of intervalley transfer, the influence of electric field on intervalley distribution and the electron kinetic energy distributions in different valleys are obtained. We propose that high valley could store energy. These results could be used as the basic data on the study of electroluminescent process.
1999, 48 (3): 539-544. doi: 10.7498/aps.48.539
(Ag,Au)/Si nanocomposite films were deposited using the rf co-sputtering method. The absorption coefficient of Ag/Si nanocomposite film was calculated based on the Maxwell-Garnett theory and differential effective medium(DEM) theory;the experimental results of spectra agreed with the DEM theory.And the possible microstructure and the reason why the plasma resonance absorption peaks were broadened have been discussed.
Monte-Carlo simulation is applied to investigate energy transfer processes in luminescence. By simulating the static distribution of the Donor-Accepter transfer rates,we have got the decay of donor luminescence in static transfer model. The result coincides with that of Inokuti-Hirayama model. The influence of D—D transfer to donor luminescence decay is simulated and discussed for both the cases of independent and correlated D—D and D—A transfer rates.
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
1999, 48 (3): 550-555. doi: 10.7498/aps.48.550
Plasma etching(PE) of cubic β-SiC single crystalline thin films produced via chemical vapor deposition(CVD) has been performed in SF6 and the SF6+O2 mixtures. Experimental results show that the maxima of etching rate are reached when gas mixing ratio is about 40%. The Auger energy spectra indicate that PE process in SF6 and the SF6+O2 mixtures does not yield a residual SiC with a C-rich surface. This technique and experimental results may serve as the foundation of fabricating various devices of SiC.
1999, 48 (3): 556-560. doi: 10.7498/aps.48.556
We have studied deep levels in AlGaInP emitter of AlGaInP/GaAs heterojunction bipolar transistor by deep-level transient spectroscopy and photoluminescence (PL) methods.Two deep levels were obtained with thermal activation energies of Ec-Et1＝0.42eV and Ec-Et2＝0.59eV,whose capture cross sections are 6.27×10-17cm2 and 6.49×10-20 cm2，where Et1 and Et2 are Si-related and O-related deep levels,respectively. The relationship between excitation power and PL peak intensity have revealed that nonradiative recombination centers of deep levels exist in AlGaInP.The current gain of AlGaInP/GaAs HBT decreases due to the existence of deep levels in AlGaInP.