A Maple package, named PLtest, is presented to study whether or not nonlinear partial differential equations (PDEs) pass the Painlevé test. This package is based on the so-called WTC-Kruskal algorithm, which combines the standard WTC algorithm and the Kruskal simplification algorithm. Therefore, we not only study whether the given PDEs pass the test or not, but also obtain its truncated expansion form related to some integrability properties. Several well-known nonlinear models with physical interests illustrate the effectiveness of this package.

By using the algebraic structure in the operator dual space in the master equation for the driven dissipative harmonic oscillator, we have rewritten the master equation as a Schrödinger-like equation. Then we have used three gauge transformations and obtained an exact solution to the master equation in the particle number representation.

Using 2N+1 successive stationary states centered at nth, we construct a rectangular wave packet in which the stationary states are superimposed with the equal weight √2N+1. With the requirement of the wave packet to be a quasi-classical state, the number N is determined by minimizing the uncertainty ΔxΔp. Since the stationary state can only be determined to within an arbitrary multiplicative complex phase factor of unit magnitude, a number of N is obtained as a set of the phases are given. For a harmonic oscillator, when all of the phase factors are essentially the same, we have N ≈ [6^1/3n^2/3] with [x] signifying the integral part of positive number x. When every phase in the phase factors is given by a random number generated in a closed interval [0,2π] and when n ≥ 10, the probability of appearance of N is roughly 1/2^N when N = 1 to 7, and does not exceed 0.01 when N ≥ 8.

We investigate the system, which consists of two two-level atoms confined in a linear trap which has been surrounded by an optical cavity, with the Milburn model of intrinsic decoherence, and find an explicit analytical solution of the Milburn equation. The entanglement between the two atoms is then calculated by making use of concurrence. The influence of intrinsic decoherence on the entanglement is also discussed.

We propose a method to test the correctness of the coupling model of a qubit interacting with environment and to determine the type of dissipation. The environment is modeled by a bath of oscillators with infinite degrees of freedom and the qubit-bath coupling is chosen to be a general dissipation-decoherence form. The proposed method can be realized in current experiments.

A large-scalable quantum computer model, whose qubits are represented by the subspace subtended by the ground state and the single exciton state on semiconductor quantum dots, is proposed. A universal set of quantum gates in this system may be achieved by a mixed approach, composed of dynamic evolution and nonadibatic geometric phase.

The big bounce singularity of a simple five-dimensional cosmological model is studied. Contrary to the standard big bang space-time singularity, this big bounce singularity is found to be an event horizon at which the scale factor and the mass density of the universe are finite, while the pressure undergoes a sudden transition from negative infinity to positive infinity. By using coordinate transformation it is also shown that before the bounce the universe contracts deflationary. According to the proper-time, the universe may have existed for an infinitely long time.

Synchronization in drive-response chaotic systems is studied. For a small mismatch of the natural frequency of the drive and response oscillators, phase synchronization comes before generalized synchronization. For moderate and even large parameter misfits, generalized synchronization can be achieved before phase synchronization. The mechanism of these two different bifurcations is interpreted in terms of the local-minimal-fluctuation method. It is found that the qualitative changes of local-minimal-fluctuations of the response system well manifests the appearance of generalized synchronization.

There are two conservation quantities needed to derive conservation laws of sine-Gordon equation in a frame of laboratory reference. One of them could be derived easily with a standard process, but the other could not. After the gauge transformation e^-iθσ₂/2 is introduced, we simply obtain the other one without any questionable assumption.

In high dimensions there are abundant coherent soliton excitations. From the known variable separation solutions for the generalized (2+1)-dimensional Nizhnik-Novikov-Veselov system, two kinds of new coherent structures in this system are obtained. Some interesting novel features of these structures are revealed.

The generalized Bethe-ansatz method of thermodynamic analysis of integrable systems was employed to compute the free energy of a classical integrable model, i.e., the Landau-Lifshitz model. Using the action-angle variables of the model and by imposing a periodic boundary condition, we derive a phase-shifted density of states for the excitations of the system. The free energy, in the thermodynamic limit, can be expressed analytic in terms of two coupled nonlinear integral equations of the finite temperature excited energy for effective phonons and kinks (antikinks). We solve these equations iteratively for a special case that the model is in the limit of anisotropic strong yz coupling.

The Δ-scaling method has been applied to ultra-relativistic p+p, C+C and Pb+Pb collision data simulated using a high energy Monte Carlo package, LUCIAE 3.0. The Δ-scaling is found to be valid for some physical variables, such as charged particle multiplicity, strange particle multiplicity and number of binary nucleon-nucleon collisions from these simulated nucleus-nucleus collisions over an extended energy ranging from E_lab = 20 to 200 A GeV. In addition we derive the information entropy from the multiplicity distribution as a function of beam energy for these collisions.

Available data regarding the nuclear halo candidates are systematically analysed in terms of the asymptotic normalization coefficients measured experimentally. On the other hand, we have put forth conditions for nuclear halo formation, and compared with the experimental data. Based on the analytical expressions of the expectation value for the operator r² in a finite square well potential, we have presented the improved scaling laws for the dimensionless quantity < r² >/R² of nuclear halo, which seem to be in reasonable agreement with the experimental data.

Properties of nuclei ^13,15N and ⁹B are investigated in the relativistic mean-field theory with NLZ and NL3 force parameters. The calculated binding energies are very close to the experimental ones. The calculations show that the first excited state (1p_1/2) in ⁹B, the first excited state (2s_1/2) in ¹³N and the second excited state (2s_1/2) in ¹⁵N are weakly bound. In particular for ¹³N and ¹⁵N, the proton density distributions in the two above excited states have a long tail and the rms radii of the last proton are greatly larger compared with their respective matter radii. It is predicted that a proton halo exists in the first excited state of ¹³N and in the second excited state of ¹⁵N, respectively. It also indicates that the first excited state in ⁹B is a proton skin state.

We establish the formalism of nuclear spin-isospin excitations, especially the Gamow-Teller resonance in a fully consistent relativistic random phase approximation. A relativistic form of the Landau-Migdal parameter g' is adopted as a residual spin-isospin correlation force. In the non-relativistic limit it reproduces the excitation energy of the giant Gamow-Teller resonance state obtained in the non-relativistic model. The Gamow-Teller resonance for finite nuclei is investigated in a relativistic approach for the first time. It is found that the Ikeda sum rule of ⁹⁰Zr is quenched about 8% in the Hartree as well as the correlated strengths due to the poles of the negative Dirac states at energies above 1 GeV.

By analysing the energy spectrum and E2 transition branching ratios, we show that the E(5) symmetry predictions agree well with the experimental data of nucleus ¹³⁰Xe. Compared the calculated results with those in the framework of the interacting boson model, it is found that the nucleus ¹³⁰Xe is definitely a nucleus in the transitional region from U(5) to O(6) symmetry. ¹³⁰Xe is then another empirical evidence of the nucleus with E(5) symmetry.

The β^- decaying γ scheme of the neutron-rich nuclide ²⁰⁸Hg has been determined for the first time. The ²⁰⁸Hg was produced in multi-nucleon transfer reaction taking place in the bombardment of ¹⁸O-beam on natural lead target, and the Hg-element products were separated with a gas-thermochromatography technique. The γ-ray single and γ-γ coincident spectra were measured. A partial ²⁰⁸Hg γ scheme was proposed. Twenty-six γ rays were assigned to follow the β^- decay of ²⁰⁸Hg. At the same time, a new level structure of the daughter nucleus ²⁰⁸Tl was constructed, in which three new levels at 1.72 MeV, 1.652 MeV, and 1.362 MeV were affirmed. The experimental ²⁰⁸Tl level structure was compared with a shell-model calculation.

The cross sections of one- and two-neutron transfers induced by ⁶He at 25 MeV/u on a ⁹Be target were measured in RIKEN. Clear identification of the recoiled Be isotopes was achieved. In total five ¹¹Be and 371 ¹⁰Be events, the corresponding two- and one-neutron transfers were obtained and analysed for transfer reaction cross sections. The results are useful to determine the spectroscopic factors of the internal halo structure of the ⁶He nucleus.

The expressions used for controlling the alignment and orientation of reagent molecules are derived. The problem to the control of the orientation and alignment of reagent molecules by the polarization direction and propagation direction of laser is discussed.

Laser-induced Coulomb explosion of CO is studied experimentally using differently polarized femtosecond laser pulses of 2 x 10¹⁵W/cm² intensity at λ = 800 nm. The channels of molecular Coulomb explosion are observed to be independent of the laser polarizations. The critical distance R is deduced to be larger for the circularly polarized light in comparison with the linearly polarized light. The initial emissions of C⁺, C²⁺, O⁺, and O²⁺ ions are anisotropic for linear polarization and isotropic for circular polarization. The suppression of ionization occurs for the elliptically and circularly polarized lasers.

The birefringence grating and the surface grating in azobenzene polymer liquid-crystal (Azo-PLC) films are studied by a near-field scanning optical microscope. With laser irradiation, the refractive index change caused by birefringence and the sinusoidal surface profile are observed at the near-field transmittance image and the surface topography of the grating. The grating period and the peak-to-peak value of the sinusoidal surface profile are 0.8μm and 40 nm, respectively. The maximum diffractive efficiency of the grating is 2%. The dynamic process of the grating formation is probed and analysed. The mass diffusion responsible for the formation of the surface grating due to the temperature rise is analysed.

If a diode pumped solid state laser is used in a holographic storage system, its multi longitudinal modes may damage the angular selectivity of the hologram and introduce more cross talk in the system. By theoretical analysis, we found that with adopting the speckle multiplexing scheme, holographic systems are no longer sensitive to the multi longitudinal modes of the laser source, and consequently the damage described above could be well suppressed. Moreover, the following high density storage experimental results also express strong advocacy of this conclusion. This result may greatly prompt the miniaturization of a holographic storage system.

The photochromic diarylethene, 1,2-bis(2-methyl-5-(4-formylphenyl)-thien-3-yl)perfluorocyclopentene (1a) is studied and its applicable potential in re-writable volume holographic data storage is verified. Holographic recording films of 10-μm thickness have been fabricated. The refractive index modulation (Δn = 1.15 x 10^-3) between the open- and close-ring forms is detected to be large enough so that the films are suitable for the production of volume holographic storage. The experiments of angle multiplexing and rewriting holograms show that the materials are fit for volume holographic data storage.

Using exact solutions of Maxwell equations based on the vector model, we calculate the diffracted near- and far-field distributions of the HE₁₁-mode output beam from a micron-sized hollow optical fibre under the Fresnel approximation, and compare the differences between the HE₁₁- and LP₀₁-mode output beams. Our study shows that it is unsuitable to calculate the diffracted near-field distribution of the hollow fibre by using weakly waveguiding approximation, and the near- and far-field intensity distributions of the HE₁₁-mode output beam are doughnut-like, which can be used to form a simple atomic funnel as it is blue-detuned.

A kind of compound external cavity semiconductor lasers (CECSL) is presented, by which laser with a discretely tunable wavelength can be obtained to meet the potential demands of the wavelength division multiplexing system. By the introduction of two-side feedback coupling in the CECSL, the CECSL can operate more efficiently, and its side-mode suppression ratio is high up to 50 dB.

We study the external optical feedback resistance of both index-coupled (IC) and gain-coupled distributed feedback (DFB) lasers using a very simple experimental set-up. Though IC-DFB lasers with large coupling coefficients are found to be less sensitive to external reflection, they suffer from mode instability at high injection level. On the other hand, the introduction of gain-coupling mechanism can significantly improve both the immunity to external optical feedback and the single mode yield of the device.

We report a diode-pumped cw Nd:YAG laser operating on the ⁴F_3/2-⁴I_9/2 transition at 946 nm, for which a maximum output power of 4.5 W with a slope efficiency of 21% is achieved at an incident pump power of 26 W. Two LiB₃O₅ (LBO) crystals of different lengths (3 x 3 x 10 mm and 3 x 3 x 15 mm), cut for critical type I phase matching at room temperature, have been used for intracavity frequency doubling, and through optimization of the structure and elements of the cavity, a maximum single-ended blue output power of 1.1 W has been obtained with an optical conversion efficiency of 4.2%. A stability better than 4.8% with no mode hopping over a period of 2 h has been achieved.

We present a method, which combines the Gaussian decomposition method and the “distributed-lens”method, for analysing Z-scan curves of cascading nonlinear medium layers or a complicated cascading structure. A good agreement with the experimental data is obtained. The method would be useful to design optical limiters and to determine the nonlinearities of cascading medium layers.

Nonlinear absorption of the organic material Zn-tetrabenzoporphin-crotonicacid-phenoxy resin (ZnTBP-CA-PhR) in the donor-acceptor energy-transfer (DA-ET) system is investigated by the irradiation of Ar⁺ laser on its solid film. A reverse saturable absorption and an enhanced second reverse saturable absorption called the re-reverse saturable absorption are observed in a visible wavelength range. The high performance of optical limiting of the sample possessing low input threshold and an over 95% linear transmission ratio are observed. The physical mechanism of re-reverse saturable absorption is analysed by a five-level rate-equation simulating. According to the Huygens wave diffraction principle and the combination of Kerr effect, thermo-optic effect and optical absorption variation, a mathematical model for the optical limiting of ZnTBP-CA-PhR film limiter is established and the theoretical simulating gives a good agreement with the experimental results.

We report the tunable mid-infrared generation with a periodically poled LiNbO₃ (PPLN). Using an all-solid-state-pumped Nd:YVO₄ laser as the pump source and a PPLN nonlinear crystal with grating periods of 28.2-30.8μm, we have achieved wavelength conversion in the 2.90-4.05μm spectral range by period tuning. The use of confocal cavity design has brought a compact, all-solid-state configuration with an average output powers of idler up to ～ 200 mW. The maximum power of 277 mW was obtained at the wavelength of 3.35μm.

We demonstrate a temperature tunable infrared optical parametric oscillator (OPO) based on periodically poled LiNbO₃ (PPLN) pumped by an acousto-optically Q-switched cw-diode-end-pumped Nd:YVO₄ laser with the signal output from 1.48μm to 1.54μm by tuning the work temperature from 60°C to 250°C and the maximum average signal power (1500 nm) of 137 mW. We report the demonstration of the sum frequency of the pump and idler in a single-grating PPLN crystal. In addition, we present the theoretical analysis of the signal wavelength change rate with the changing temperature for a quasi-phase matching OPO, which is in good agreement with our experimental results.

A Mach-Zehnder electro-optic modulator is designed and fabricated based on upper-clad GeO₂-doped silica ridge waveguides with thermal poling. The electro-optic coefficient obtained is about 0.05 pm/V and is polarization-insensitive. An extinction ratio of over 17 dB is achieved. The transmission loss of the modulator for the TE mode is 2-3 dB higher than that for the TM mode after the poling.

Based on the expression of the dispersion equation of Lamb waves in an adhesive two-layered plate presented in our previous paper [Chin. Phys. Lett. 18(2001)1483], the two lowest Lamb modes, the symmetric mode S₀ and the anti-symmetric mode A₀ are successfully decomposed in the low-frequency regime. Relations between the rigidity of the bond and the velocity of the two Lamb modes are found, which lay a foundation for the estimation of the bond rigidity of the adhesive plate. The influence of the variations of the bond rigidity in terms of the stiffness constants K_N and K_T of the spring model on the velocity of the two Lamb modes is discussed and numerically evaluated. Numerical results indicate that the deterioration of the bond rigidity causes the phase velocity decrease for Lamb modes of the two lowest order, thus having a possibility for the evaluation of the bonding state of the adhesive plate by using ultrasonic wave velocity measurement.

A novel method to correct diffraction effect in measurement of ultrasonic velocity and attenuation at high frequencies is developed by using the superposition technique of Gaussian beams. To examine the validity of this numerical approach, the amplitude loss and phase advance due to the diffraction effect for an SiO₂ specimen are numerically calculated in 30-240 MHz, and the results are in good agreement with those by the Papadakis method.

A bidisperse granular mixture in a slightly tilted compartmentalized chamber is experimentally found to show size segregation when vertically vibrated. A surface slope develops and large particles congregate to the lower side. Particles right upon the upper tip of the dividing wall behave in a competitive way, i.e., they can go to either compartment depending on the force exerted on them.

We study the flow of a density-stratified fluid passing over an isolated obstacle, using towing-tank experiments. Our special concern is the response of the flow with different Froude numbers pasing over a three-dimensional obstacle. A series of experiments of the stratified rotating flow passing over an isolated obstacle was carried out with the towering-tank controlled by the similarity laws and dynamic non-dimension parameters. These experiments show that the Froude number is a very important parameter, and the lee wave and the eddy structure appear simultaneously under an appropriate conditions. The effect of rotation on the lee wave is mainly to change wave amplitude, particularly to restain the development of the lee wave and to promote the formation of an eddy.

In order to estimate the erosion rates of some plasma facing component materials, the sputtering yields of Mo, W and deuterium-saturated Li bombarded by fusion charged particles are calculated by application of new sputtering physics description methods based on the bipartition model of ion transport theory. The comparisons with Monte Carlo calculation and experimental results are made. These data might be useful to estimate the lifetime of plasma facing components and to analyse the impurity level in core plasma of fusion reactors.

The viscosity of Cu melt is obtained to be in the ranges from 2.418 to 3.039 mPa.s under vacuum atmosphere (2Pa), from 2.907 to 3.425 mPa.s under nitrogen gas atmosphere and from 3.352 to 4.015 mPa.s under argon gas atmosphere. The activation energy is estimated to be 0.224, 0.162 and 0.150eV for the vacuum atmosphere (2Pa), nitrogen gas atmosphere and argon gas atmosphere, respectively. The results reflect the essential structural change in the Cu melt by using different atmospheres.

The defect changes in 6H-SiC after annealing and 10 MeV electron irradiation have been studied by using a variable-energy positron beam. It was found that after annealing, the defect concentration in n-type 6H-SiC decreased due to recombination with interstitials. When the sample was annealed at 1400 °C for 30 min in vacuum, a 20-nm thickness Si layer was found on the top of the SiC substrate, this is a direct proof of the Si atoms diffusing to surface when annealed at high temperature stages. After 10 MeV electron irradiation, for n-type 6H-SiC, the S parameter increased from 0.4739 to 0.4822, and the relative positron-trapping rate was about 27.878 times of the origin sample, this shows that there are some defects created in n-type 6H-SiC. For p-type 6H-SiC, it is very unclear, this may be because of the opposite charge of vacancy defects.

A new iron film system, deposited on silicone oil surfaces by vapor phase deposition method, has been fabricated and its formation mechanism as well as orderly structures has been studied. It is found that the formation mechanism of the films obeys a two-stage growth model, which is similar to that of the other metallic films on liquid substrates. Large and orderly structures are observed in the continuous iron films. The experiments show that the orderly spatial structures result from the local material gathering in these nearly free sustained films.

For the Bariev model with single electron hopping, pair hopping and hard core potential, we prove the integrability of this model under open boundary conditions and obtained the Bethe ansatz equations by using the reflection equations of the open-boundary XXZ model.

The temperature dependence of resistivity ρ of YSZ doping composite of (1-x)La_0.67Ca_0.33MnO₃ + xYSZ and Y₂O₃ doping composite of (1-y)La_0.67Ca_0.33MnO₃ + yY₂O₃ is investigated, respectively, in a temperature range 77-300 K, where the YSZ represents yttria-stabilized zirconia (8 mol%Y₂O₃ + 92 mol% ZrO₂). Experimental results show that the YSZ doping level has important effects on both the metal-insulator (M-I) transition temperatures and zero field resistivity of the composites of (1-x)La_0.67Ca_0.33MnO₃ + xYSZ. However, the Y₂O₃ doping level has little effect on the M-I transition temperatures and the zero field resistivity of (1-y)La_0.67Ca_0.33MnO₃ + yY₂O₃ only increases slightly. The difference between the two types of composites may mainly result from the different distribution of high resistance phases at the grain boundaries and/or surfaces of La_0.67Ca_0.33MnO₃ grains rather than the substitution of La³⁺ ions with Y³⁺ ions.

We study the oscillator strengths of the optical transitions of the vertically stacked self-assembled InAs quantum disks. The oscillator strengths change evidently when the two quantum disks are far apart from each other. A vertically applied electric field affects the oscillator strengths severely, while the oscillator strengths change slowly as the radius of one disk increases. We also studied the excitonic energy of the system, including the Coulomb interaction. The excitonic energy increases with the increasing radius of one disk, but decreases as a vertically applied electric field increases.

Recent studies have indicated that spin polarization of the conductance shows strong oscillation and zero average for electrons resonant tunneling through a magnetic double-barrier and double-well quantum structure. Our studies indicate that strong oscillation of the polarization of the conductance is not physically intrinsic but inaccurate due to problems of numeration and insufficient numerical accuracy. We also indicate that its average of the spin polarization is not zero. The reasonable explanation is presented in details.

We investigate the electronic structures and superconductivities of new superconductor MgB₂ with different lattice parameters by means of multiple-scattered-Xα calculation. It is shown that the lattice parameters have great effect on the superconductivity of MgB₂. The results of this paper show that the density of states at the Fermi level decreases with the decreasing lattice parameters. The effects are very more sensitive substantially to the change of the lattice parameter a as compared with that of the lattice parameter c. Correspondingly, the superconducting transition temperature T_c decreases correspondingly mainly with decreasing the lattice parameter a. Our results are in good agreement with the experiments.

The room-temperature second-, third- and fourth-order nonlinear dielectric constants of poled (1-x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ single crystals were determined by measuring the dielectric response at a frequency of 10 kHz and under a dc bias of 0-1000 V/mm. Tunability of the apparent dielectric constant ε_r was also defined and examined. The results show the phase structure, domain state, composition and orientation dependences of the dielectric nonlinearity and tunability. It is also shown that the <011>-poled monodomain orthorhombic ferroelectric 0.67Pb(Mg_1/3Nb_2/3)O₃-0.33PbTiO₃ single crystal has the largest nonlinear dielectric constants and the highest tunability of ε_r in the monodomain crystals. It could be a most promising candidate for applications where a high dielectric nonlinearity is needed.

The size driven ferroelectric-paraelectric phase transition in a ferroelectric of small size is studied within the framework of Landau phase transition theory. The transition is a consequence of the competition between the decrease of the volume free energy by polarization and the increase of the surface energy of the ferroelectric phase, which has a surface energy density higher than that in the paraelectric phase. A simple expression for the ferroelectric critical size as a function of the Landau free energy coefficients and the surface energy density is derived.

The blue band (BB) in low temperature photoluminescence of Mg-doped GaN films with different Mg concentrations is investigated. The BB peak of as-grown samples with higher Mg concentration centers at lower energy. A shift of the BB peak energy is observed after annealing in N₂ at different temperatures. Meanwhile, the difference between the BB peak energies diminishes for raised annealing temperature, and the BB peaks for different samples converge to 2.92 eV after annealing at 850 °C. These experimental results can be accounted for by a model based on compensation effect. The shift of BB lines provides a useful criterion for the optimum annealing temperature of the Mg-doped GaN material, and the value is taken to be 850 °C in our case.

A new phosphorescent material bis(2-phenyl-benzoimiazole) acetylacetonato iridium ((PBI)₂IrAcac) is designed and synthesized. The absorption, photoluminescence and electroluminescence are measured. The polymer-based light-emitting devices which use polyvinylcarbazole (PVK) as host and (PBI)₂IrAcac as emitter were fabricated. These light-emitting devices show a bright green emission at 548 nm. The device ITO/(PBI)₂IrAcac:PVK/BCP/ Alq₃/Mg:Ag shows a very high efficiency. A peak external quantum efficiency of 21.5 cd/A (5.8%) was obtained at 0.1 mA/cm². The maximum brightness is 3840 cd/m².

Based on our previous discovery [Chem. Phys. Lett. 325 (2000) 420] of the solid-state cathodoluminescence from organic luminescent materials in inorganic/organic heterojunction, we study characteristics of this new kind of electric-field-induced luminescence by means of examining its oscillogram. We prepared three devices with different structures in which PPV was used as luminescent layer, and SiO₂ was used as accelerating layer. The experimental results might be understood only by means of the existence of solid-state cathodoluminescence. This new kind of luminescence makes it possible to produce new type of flat panel display.

We study the two samples of AlInGaN, i.e., 1-μm GaN grown at 1030°C on the buffer and followed by a 0.6-μm-thick epilayer of AlInGaN under the low pressure of 76 Torr and the AlInGaN layer deposited directly on the buffer layer without the high-temperature GaN layer, by temperature-dependent photoluminescence (PL) spectroscopy and picosecond time-resolved photoluminescence (TRPL) spectroscopy. The TRPL signals of both the samples were fitted well as a stretched exponential decay at all temperatures, indicating significant disorder in the material. We attribute the disorder to nanoscale quantum dots or disks of high indium concentration. Temperature dependence of dispersive exponent β shows that the stretched exponential decay of the two samples comes from different mechanisms. The different depths of the localization potential account for the difference, which is illustrated by the results of temperature dependence of radiative recombination lifetime and PL peak energy.

We use the multiple-scattering cluster method to calculate the sulfur 1s near-edge x-ray absorption fine structure (NEXAFS) of S-passivated InP(100) surface. The physical origins of the resonances in the NEXAFS have been unveiled. It is shown that the most important resonance is attributed to the photoelectron scattering between the central sulfur and the nearest indium atoms. The studies show that two S-S dimers with the bond lengthes of 2.05Å and 3.05Å coexist in the surface, meanwhile the bridge and antibridge site adsorption of single S could not be ruled out. We support the scanning tunneling microscopy result that the S-passivated InP(100) surface exhibits significant disorder.

ZnO thin films with the c-axis orientation on the (0001) sapphire substrate were grown by metal-organic chemical vapor deposition. It was demonstrated that the VI/II precursor flow-rate ratio can influence strongly on the structure and opto-electrical properties. With the increasing VI/II ratio of 130:1, the full width at half maximum of (0002) peak in x-ray diffraction is only 0.184°, the near-band-edge emission enhances remarkably and the intensity ratio of the near-band-edge emission to the deep-level emission reaches 237:1 in the photoluminescence spectrum. At the same time, the resistivity and mobility increases to 3.28 x 10²Ω.cm and 25.3cm²V^-1s^-1. These facts indicates that the quality of the ZnO thin films could be improved by the increase of the VI/II flow rate ratio during the growth.

The kinetics and dynamics for the growth of hydrogen bonding clusters in the A_a-D_d system are considered. The explicit relations between conversions of proton-acceptors and proton-donors and Gibbs free energy are deduced, and then the sol-gel phase transition is predicted to take place and the generalized scaling laws satisfied by the k-th moment and k-th radius near the critical point are given. The conclusions obtained from which are consistent with the statistical descriptions on the system under investigation.

A series of spin transition complexes [Fe_1-xZn_x(dpp)₂(NCS)₂]py (x = 0.05, 0.10, 0.15. 0.20, 0.25, and 0.40; py=pyridine) has been synthesized and studied by Mössbauer spectroscopy. The high spin structure is frozen at room temperature, and the induced meta-stable high-spin phase by the so-called rapid cooling method is monitored by temperature and time dependent Mössbauer spectra. The investigation on dynamic relaxation of the high-spin state to the low spin state at 80 K reveals sigmoid behaviour and existence of cooperative effect for low diluted complexes. This cooperative effect is wrecked by the dilution of Zn(II) ions in Fe(II) ion sites, and relaxation curves gradually become to obey the first-order kinetics as the ratio of the dilution increases.

Wavelength dependence of electro-optic coefficients in chromophore-incorporated polymers is studied by using the attenuated-total-reflection technique. Experimental result shows that the electro-optic coefficient decreases with the increase of light wavelength, which is in agreement well with the theoretical prediction.

Intracellular Ca²⁺ concentration oscillation is one of the typical nonlinear dynamical phenomena in biophysics. According to the experimental facts that when stimulated by different agonists, the cytosolic Ca²⁺ oscillations of hepatocytes show nearly constant amplitude for two different oscillation-form, simple spikes and complex bursts, we build a new 4-variables model based on the two models proposed by Hoefer [ Biophys J. 77 (1999) 1244] and Kummer et al. [ Biophys. J. 79 (2000) 1188] Our model can simulate both simple-spike and multi-spike-burst oscillations with amplitude of 0.5-0.7μmol/L in a rather wide range of parameters.

We carry out the in-situ high pressure energy dispersive x-ray diffraction measurements on natural epitote by using diamond anvil cell. The pressure dependence of the lattice parameters of natural epidote is reported up to 20 GPa at room temperature. The experimental results show that the compressibility of epidote along the crystal axes is similar with increasing pressure, and the room-temperature isothermal bulk modulus K₂₉₈ is 207±15 GPa, which is fitted by the Murnaghan equation of state in the case of the pressure derivative K'= 4.

A series of newly published papers are focusing on the formation of the absorption features discovered by Chandra and XMM-Newton from the young radio quiet x-ray pulsar 1E 1207.4-5209. We try to interpret it as cyclotron absorption lines since this possibility could not be ruled out. With new development and application of a hybrid model, i.e., the magnetic dipole spin-down model combined with the neutrino cyclotron radiation spin-down model, we can easily avoid the contradiction between the normal rotation energy loss rate and the relatively lower magnetic field, and then we obtain the possible initial spin period (～0.420 s). We suppose that the progenitor of 1E 1207.4-5209 may be a white dwarf.

We solve a set of basic equations describing black hole accretion flows using the standard Runge-Kutta method and a bridging formula for the radiative cooling, and show that a smooth transition from an Shakura-Sunyaev disc to an advection-dominated accretion flow is realizable for the high-viscosity case, without the need of involving any extra mechanism of energy transport.

We have collected 18 γ-ray-loud BL Lac with observed data in multiwavedand, we find that γ-ray flux densities correlate better with the near-IR flux densities than those with the optical or x-ray flux densities. There is no correlation between γ-ray and radio flux densities. Possible constraints on the γ-ray emission mechanism are discussed. We suggest that the main γ-ray radiation mechanism is probably the synchrotron self-Compton process. The inverse Compton scattering of the radiation from hot circumscribe dust, by beamed ultrarelativistic electrons, is likely to be an important complementary mechanism.

It is stated that the conjecture that the hydrogen-like atoms may have large permanent electric dipole moments is doubtable. Two kinds of experiments are suggested to check the reliability of the conjecture further.

The result of our experiment on Rb atoms is interesting and surprising. To affirm or to refuse the result should not be by conjectures but by experiments.