Vol. 45, No. 3 (1996)
1996-02-05
GENERAL
1996, 45 (3): 353-359.
doi: 10.7498/aps.45.353
Abstract +
The relation analogous to the uncertainty relation of quantum mechanics also exists in classical mechanics. In this paper by using this relation we calculate several examples. From the results of the calculations it is obvious that a wave function can only describe the ensemble in the classical limit.
1996, 45 (3): 360-369.
doi: 10.7498/aps.45.360
Abstract +
In this paper, double wave function quantum theory is applied to obtain a time evolution equation to describe the physical quantities of single motional particle in the reflectionless potential well. The ordinary formula to calculate mean values in quantum mechanics can be described as the average of double wave function of a certain ensemble.
1996, 45 (3): 370-372.
doi: 10.7498/aps.45.370
Abstract +
It is pointed out that if collision term in lattice Boltzmann equation is changed from Fermi type to Boltzmann type, viscosity coefficient will be decreased greatly. Low viscosity makes lattice Boltzmann equation method more effecient in simulating fluid behaviors. Theoretical solution is coherent with simulation results.
THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
1996, 45 (3): 373-379.
doi: 10.7498/aps.45.373
Abstract +
It is discussed that the parity conservation is not true when q≠0, i.e., the magnetic charge g≠0 for the electron-Dirac dyon bound system, so that the transitions are not forbiden when △j = 0 and the linear Stark effect may occur. The splitting of this effect is calculated. The features different from hydrogen-like atoms are also briefly discussed.
CLASSICAL AREA OF PHENOMENOLOGY
1996, 45 (3): 380-388.
doi: 10.7498/aps.45.380
Abstract +
The temporal behavior of DFWM and holography in four-level saturable and reverse saturable absorbers was analysed theoretically. It was demostrated that the signal response time, intensity and decay were dependent on laser exciting intensities, sample saturable intensity and triplet lifetime. An experimental verification was performed in molecule ethyl orange.
1996, 45 (3): 389-393.
doi: 10.7498/aps.45.389
Abstract +
In this article, we have studied how to generate macroscopic quantum superposition states in electromagnetic field, the Schrodinger cat states, from the large-detuning degenerate Raman process and the large-detuning two-photon Jaynes-Cummings model. The homodyne detection of these states is also discussed. When the initial state of the field is the Schrodinger cat state, the effects of the cat state on the collapse and revival phenomena in the intensity-dependent Jaynes-Cummings model are investigated. The revival in varying degrees occurs in the collapse region resulted from the evolution of initial coherent state.
1996, 45 (3): 394-402.
doi: 10.7498/aps.45.394
Abstract +
The micro-Hamiltonian of optical fiber soliton system is obtained, and quantum nonlinear Schrodinger equation (QNSE) with corrections of femto-second soliton propagating in single-mode fiber is derived using the Hamiltonian and dispersion relation. The derived equation is solved with Hartrec approximation. The quantum feature of soliton and classical transition arc studied. Several results are obtained: The mean value of the field in fiber is the average of a set of classical solitons with corrections; as the propagation distance increases, the phase spreads and the soliton becomes self-squeezed, and the result of self-squeezing is relative to higher-terms.
1996, 45 (3): 403-408.
doi: 10.7498/aps.45.403
Abstract +
It is known that the Brownian motion is concerned with the aggregation of particle- chains in electrorheological fluids (ERF) under external field. In this paper we suggest a two-sphere model in which we assume that there is internal motion between two spheres but they keep separation from each other for simplifying particle-chain in ERF. Analysing the properties of the Brownian motion of the two-sphere system the result of its trace fractal dimension less than 2 is obtained. In view of the dimension of motion-trace a qualitative explanation of the aggregation of particle-chains in ERF subjected to external electric field, i.e. ,phase separation,is given.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
1996, 45 (3): 409-412.
doi: 10.7498/aps.45.409
Abstract +
Recycling in the HT-6M tokamak is studied by changing the working gas from deuterium to hydrogen and vice versa. Spectroscopic technique (Balmer lines) is used to follow the change of the relative concentration of the plasma. The results show that the reflection coefficient near the wall is about 0. 59, and in the plasma of the first discharge after a gas change, the wall-released isotope amount to 65% .The recyclingc mechanism in the HT-6M tokamak is discussed.
1996, 45 (3): 413-419.
doi: 10.7498/aps.45.413
Abstract +
In this paper,the effect of hot electron and warm(hot) ion components on the drift-cyclotron-instability(DCI)is studied. Some relations are given as follows:The dependence of marginal stable hot electron value on warm (hot) ion value; the temperature ratio of warm (hot) ion to cold ion; and ion diamagnetic drift velocity. The influences of hot electron and warm (hot) ion on the different DCI harmonic branchs are discussed. The stable mechanism of hot electron is analysed for the first time.
1996, 45 (3): 420-427.
doi: 10.7498/aps.45.420
Abstract +
The universal degenerate and nearly degenerate FWM nonlinear equations in uniform magnetized plasma are given for the formation of reflection grating configuration and its exact solution appropriated for arbitrary complex coupling parameters under undepleted pump assumption is obtained. The solution is quite suited to various plasma situations but also can be extended to photorafractive materials. It is hoped that it may be helpful for further studying FWM' s phase conjugation theory and developing new nonlinear optical device , especially , for developing new fusion diagnostics by using FWM's principle.
1996, 45 (3): 428-435.
doi: 10.7498/aps.45.428
Abstract +
In this paper, a self-consistent Monte Carlo simulation method including charge exchange and elastic scattering is developed, and the method is used to calculate the energy and angle distributions of ions, the density distributions of ions and electron in hollow-cathode sheath of a DC argon gas discharge for the different discharge conditions. Cross sections of the charge exchange and the momentum transfer that depend on the ion energy are taken into account precisely. It is found that, as the ions move towards the cathode, the high energy portions of ion energy distributions are enhanced gradually and the small angle portions of the angle distribution increase. A strong field accelerates the ions to higher speed and ensures more ions to move along the lines of force.
1996, 45 (3): 436-442.
doi: 10.7498/aps.45.436
Abstract +
The experimental investigation of X-ray radiation characterized by the cavity targets was carried out at the Shenguang laser facility. The temperature profile along the axis of the cavity target was given. The first X-ray radiation from the laser heating phase and the second X-ray radiation from the expanded plasma collision phase were measured. The time interval between the two radiations was about 1.2 ns. The spectrum of the radiation from the implosion region was similar to a Planck spectrum.
1996, 45 (3): 443-448.
doi: 10.7498/aps.45.443
Abstract +
Radiation temperature in hohlraums is diagnosed using two soft X-ray spectrometers and multi-pinhole soft X-ray streak camera. We have improved the accuracy taking plasma closure effects of the diagnostic hole into consideration. We have obtained 2D-images and processes of the hole closure and radiation temperature in the hohlraums νs time. A preliminary model of the closure effect of diagnostic hole is proposed based on the experimental data.
1996, 45 (3): 449-454.
doi: 10.7498/aps.45.449
Abstract +
Hydrogen ion energy spectra during NBI heating were investigated by energy analysis of charge-exchange neutral particle. The results indicate that ion temperature has been increased. The rise of ion temperature is in agreement with the values calculated by the method of the empirical scaling law.The Fokker-Planck equation is used to calculate charge-exchange spectra and ion temperature, and compare them with the experiment results.
1996, 45 (3): 455-463.
doi: 10.7498/aps.45.455
Abstract +
Plasma-Polymerized organic film starting from thiophene has been prepared. The elemental composition of pristine film was determined by elastic recoil detection (ERD) and Rutherford backscattering spectrum (RBS). FT-IR technique has been used to characterize the sample film. From the near-IR to UV reflectance and transmittance data, we calculated the optical constants of the film, N(ω) = n + ik ,by using the transfer matrix method. In view of the calculations, we investigated the optical properties of the pristine in detail. Moreover, the doping effect in the plasma-polymerized thiophene film with 24 keV I+ implantation has been also explored. The result shows that the transport process of charge carrier in bombarded layer can be interpreted by Mott's VRH model.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
1996, 45 (3): 464-469.
doi: 10.7498/aps.45.464
Abstract +
A new kind of coherent segregation would form in the Fe-10% Cr which was proton-implanted at R.T. and was irradiated with electrons at 623 - 723 K. Streak diffraction patterns can be observed at the same time. Such segregations were formed along the directions of ,having a length of about 100 nm and a diameter of about 1-2 atom size. Hydrogen and pure point defects produced by electron irradiation were considered to be the cause of the formation of segregation.
1996, 45 (3): 470-479.
doi: 10.7498/aps.45.470
Abstract +
Millimeter-sized C60 single crystals with regular, shiny and smooth faces were grown from vapor phase. The structure of C60 crystals was confirmed to be face-centered-cubic (fcc, a = 1. 4199(4) nm) by X-ray diffraction at room temperature. The morphologies and growth defects were studied by both the scanning electron microscope and the optical microscope. In addition to the typical stable {111} and {200} faces and twins for fcc crystals, we also observed the dentrites,ridge like defects and growth hillocks on {111} faces and dentrites,growth hillocks and swimming-pool-like defects on {200} faces. The morphologies appeared were compared with the theoretical equilibrium forms. The mechanism of the formation of the growth defects were analysed. The effects of growth conditions on the growth morphology of C60 crystals were discussed. These results will be helpful for the investigation or the growth mechanism of C60 single crystals by vapor transport method.
1996, 45 (3): 480-485.
doi: 10.7498/aps.45.480
Abstract +
Self-consistent equation for order parameter of nematic liquid crystal (LC) in solution is obtained on the basis of Lebwohl-Lasher model and mean-field approximation. Numerical calculation shows that LC in solution with different volume fractions all undergo the first-order phase transition at 2> =0.324 without external fields, and TN1 is proportional to the volume fraction, TφN1= Tφ=1N1φ. Under applied external fields, LCs undergo second-order phase transition at 2 > = 0.40. Distribution curves are in Ⅴ shape. The variation of the distribution mean square errors with> has a maximum at 2> = 0.20.
1996, 45 (3): 486-490.
doi: 10.7498/aps.45.486
Abstract +
Focused Ga+ ion beam implantation was used to make the semiconductor quantum well wire in GaAs/Al0.3Ga0.7As multi-quantum well structure. Making use of the low temperaturer PL spectra, we studied the optoelectronic properties of the quantum wire, and observed the blue shift caused by the channel effect in deep quantum well.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
1996, 45 (3): 491-498.
doi: 10.7498/aps.45.491
Abstract +
This work presents a detailed study of deep and shallow level defects in nitrogen implanted n-type GaAs. Deep-level transient spectroscopy (DLTS) measurements show four electron traps and one hole trap in 140 keV nitrogen implanted GaAs after a dose of 1×1013cm-2 and a thermal annealing at 800℃ for 30 min: E1(0.111) ,E2(0.234) ,E3(0.415) ,E4(0.669) ,and H(0.545). Meanwhile,only E4 and H(0.545) defects are observed in 10 keV nitrogen-implanted GaAs after a dose of 5×1014cm-2 and the same annealing treatment. It oncluded that E2 and E3 correspond to the damages due to the high-energy implantation, E4 may be complex of intrinsic defect and implantation damage, H(0.545)is a nitrogen-related deep-level and may contribute to the free-carrier compensation in the nitrogen-implanted n-type GaAs.
1996, 45 (3): 499-505.
doi: 10.7498/aps.45.499
Abstract +
Thermally stimulated conductivity (TSC) theory based on multiple trapping(MT) model in amorphous semiconductors is limited to explain TSC in a-Si: H at low temperatures in which the low temperature peak of TSC σTSC( TM) is independent of the starting temperature T0. TM is pinked. In this paper, a model of the hopping conduction with the transport energy Et in the band tail is proposed to understand the behavior of the low temperature TSC. Hopping frequency, thermal emission rate and temperature dependence of Et were calculated. TM is suggested to be corresponding to a change of the transport mechanism from hopping conduction to MT model.
1996, 45 (3): 506-511.
doi: 10.7498/aps.45.506
Abstract +
We have used STM to investigate the electron tunneling spectroscopy, as well as the tunneling barrier heights,in two kinds of iron oxides prepared differently on iron single crystal surfaces. The experimental results agree reasonably well with that of calculation employing stationary state tunneling method, and show that the iron oxide formed under ambient temperature (type Ⅰ) is mainly consisted of Fe3O4, while the surface processed by flash oxidation (type Ⅱ) should be consisted of high barrier oxides, most likely Fe2O3. Therefore, STM could be used to study various stages of surface oxidation on iron single crystal surfaces. The results aslo indicate that STM could be applied to study a range of metal oxides, and it is possible to investigate the internal structures of certain metal oxides possessing low barrier heights characteristics.
1996, 45 (3): 512-517.
doi: 10.7498/aps.45.512
Abstract +
The electronic energy bands of a series of β phases of carbon nitride, silicon nitride and germanium nitride have been calculated using a first-principle linear combination of muffin-tin orbital method with the atomic-sphere approximation(LMTO-ASA). The band gaps obtained for the three compounds are 4. 1751,5. 1788 and 4. 0279 eV, respectively. For β-C3N4 ,the nitrogen 2p orbitals plays an important role in the top of valence band(VB) due to its non-bonding. For -β-Si3N4,the silicon 3d orbitals plays an important role both in the VB and in the conduction band(CB). Its band gap is indirect which is in agreement with other calculated results. For β-Ge3N4,the germanium 3d orbitals preserve the characteristics of atomic orbitals and give very little contributions to other VBs and CB. Its 4d empty orbitals play a role analogue to 3d of Si of β-Si3N4. This is the frist theoretical study reported on the electronic structure of β-Ge3N4.
1996, 45 (3): 518-521.
doi: 10.7498/aps.45.518
Abstract +
The dependences of stress on strain, strain on the critical current density, and the relation of Jc(H) at several strains were measured in Bi-2223 silver clamped thick film. The results indicate that the stress-strain curve exists two strain transitions which are respectively correspond to the beginning and ending of breaking in Bi1.8Pb0.4Sr2Ca2Cu3Oy thick film. At △X/X≤2.5 % , the critical crrrent density Jc decreases slowly with △X/X increasing. At △X/X≥2.5 % , Jc decreases rapidly with △X/X increasing. As strain increases,the characteristics of Jc(H) decrease rapidly and the weak link junctions emerges obviously. The mi-crostructures show that the decrease of Jc and the variance of characteristics of Jc (H) relate to the breaking of intergrains and grains in the thick film.
1996, 45 (3): 522-527.
doi: 10.7498/aps.45.522
Abstract +
A spin wave approach to study the anisotropic Heisenberg antiferromagnet is presented. By means of introducing a parity operator and canonical transformations, the Hamiltonian is diagonized, based on the Holstein-Primakoff transformation, to obtain dispersion relations of the spin waves. The terms of non-linear approximation effects for the ground state energy and the dispersion relations are also shown.
1996, 45 (3): 528-532.
doi: 10.7498/aps.45.528
Abstract +
The Mossbauer spectra were measured at room temperature for the nanocrystalline Fe73.5Cu1Mo3Si13.5B9 alloys at the as-cast state and the anneals at various temperatures. The results of measurements demonstrate the co-existence of the α-Fe(Si) nanocrystalline phase and interficial amorphous phase in the crystallized alloys. The variations of the hyperfine field and relative areas of these phases with the annealing temperature are attributed to the annealing-induced diffusion of Cu,Mo, B and their redistributions in these phases.30 percent of iron contained in the amorphous phase was found and this state of affairs corresponds to the best magnetic properties. The two-phase, disordered anisotropy model makes clear, that a certain amount of amorphous phase was essential to the excellent soft magnetic properties of nanocrystalline alloys. The deterioration of the properties is due to the existence of Fe2B phase .
1996, 45 (3): 533-538.
doi: 10.7498/aps.45.533
Abstract +
Two series of [Pd/Co-Nb/Pd/Si] multilayer films were prepared by rf sputtering. The measurements of structure and magnetism were made by X-ray diffraction and magnetometer, respectively. As the thickness of Pd layers increases, the structure of Pd layers transfers from an amorphous state to a polycrystalline state. The polycrystalline state of the Pd layers shows two adjacent Pd fcc(111) peaks, which originate from the differences of lattice-mismatching degree and polarization of Pd atoms between the interfaces of Co-Nb layers and Pd layers and the interfaces of Pd layers and Si layers. As the thickness of Pd layers increases, the saturation magnetization monotonously increases from a value which is smaller than that of the bulk Co-Nb alloy with the same compositions to another value which is larger, then takes a constant value. This is contributed to the effects of polarization of Pd layers, dimension of Co-Nb magnetic layers and interdiffusion of atoms in the interfaces. The amorphous Co-Nb layers can influence the polarization of Pd atoms in the range of 2.5nm from the interfaces of Co-Nb layers and Pd layers. The is related to the strong interdiffusion of atoms in the interfaces and the large change of the Pd lattice constant in the film normal.
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
1996, 45 (3): 539-544.
doi: 10.7498/aps.45.539
Abstract +
The optimum surface coverage of diamond by hydrogen during chemical vapor depositon processes has been studied. It is assumed that the reduced chemical reaction of the singlet state of the surface dangling-bonds is different from that of the dangling-bonds-clusters in which the dangling-bonds may combine each other at the surface and form non-diamond structrures. The singlet states of the surface dangling bonds may be the main templets contributed to the diamond growth. It has been observed that the optimum surface coverage is 0.86 monolayer (ML)for {111} oriented surface , and 0.80 ML for {100} oriented surface for diamond growth, and it may be the maximum growth rate at a definite concentration of hydrocarbon fragments at the surface.
