The quantum non-cloning theorem is discussed for Garfinkle--Horne dilaton black holes. It is found that if the black hole complementarity principle is correct, then it will be questioned whether the quantum non-cloning theorem is well established inside the inner horizon. It is also found that another complementarity principle may be needed inside the inner horizon of the Garfinkle--Horne dilaton black hole.

We suggest two schemes to generate the W state of N Λ-type three-level atoms. In the schemes, identical N three-level atoms are trapped in a cavity or N distant cavities. The success or failure of the generation of the W state can be determined by detecting the polarization of photon leaking out of the cavity. The result demonstrates that the W state is free from both the cavity loss and the spontaneous emission due to the fact that the two ground states (left and right) of the three-level atoms are stable states (or metastable states).

We study quantum games in which the players have different strategic spaces. We find that the player who can use a quantum strategic space does not always possess more payoffs than the player who is restricted to apply only classical strategies. We find the condition of the classical player getting more payoffs than the quantum player. We also find that the game exhibits intriguing structures.

With the help of symbolic computation, the tanh method is extended to find some new exact solutions of nonlinear Gross--Pitaevskii equation with weak bias magnetic and time-dependent laser fields. As a result, the bright and dark soliton solutions are obtained. In addition, some new soliton solutions in this model are found

Study of beam halo-chaos has become a key issue of concern for many future important applications. Control of halo-chaos has been researched intensively. This is the first time that the synchronization of beam halo-chaos has been realized in this field so far. Two nonlinear feedback control methods are proposed for the cascading synchronizing halo-chaos in coupled lattices of a periodic focusing channel. The simulation results show that the methods are effective. The realization of the synchronization of beam halo-chaos is significant not only for halo-chaos control itself but also for halo-chaos-based secure communication which may become an innovative technique.

The dynamics of systems consisting of coupled quantum--classical oscillators is numerically investigated. It is shown that, under certain conditions, the quantum oscillator exhibits chaos. When the mass of the classical oscillator increases, the chaos will be suppressed; if the energy of the system and/or the coupling strength between the two oscillators increases, chaotic behaviour of the system appears. This result will be helpful to understand the probability of the emergence of quantum chaos and may be applied to explain the spectra of complex atoms qualitatively.

We report a continuous transition from outwardly rotating spiral waves to antispirals in the complex Ginzburg--Landau equation. Numerical simulations demonstrate that the normal spiral to antispiral transition is fulfilled through a rest spiral wave with zero propagation speed. The propagation direction of spiral waves and the power law behaviour close to the transition boundary are examined.

A new chaotic communication scheme is constructed. Different from the existing literature, cascade chaotic systems are employed. Two cascade modes are considered. First, we investigate the input to state cascade mode; cascade systems between different kinds of chaotic systems are considered. Then the parameter cascade case of chaotic system is studied. Under the different cases, the corresponding receivers are designed, which can succeed in recovering the former emitted signal. Simulations are performed to verify the validity of the proposed main results.

A new chaotic communication scheme based on generalized chaotic synchronization (GCS) and hash function transpositions is presented. The communication scheme has nonsymmetric secrete keys and its ability is similar to traditional digital signatures, i.e.a receiver can convince himself whether or not the sender's message contents have been modified. As a direct application of the scheme, a GCS system is designed by using Chen's chaotic circuit and is studied in some detail. The numerical simulation shows that this Chen GCS system has high security and is fast and reliable for secure Internet communications.

The Bäcklund transformation and variable separation approach are developed for sine-Gordon systems. Three new types of variable separated solutions with some arbitrary functions have been obtained. A new kind of ghoston structure, which is invisible at most of time and can only be detected when it meets with a foldon, is found. This new structure shows a novel interesting and mysterious phenomenon.

Starting from a simplified model involving the interactions between colour quark fields, colour-SU(3) gauge fields, and colour scalar fields, it is shown, to the lowest-order approximation in ħ, that the vacuum expectation value of the gauge fields is equivalent, mathematically, to the vacuum expectation value of the scalar fields. Based on this relationship, a soliton solution of the gauge fields is given by solving the Euler equation of the scalar fields.

The effect of tensor interaction due to gluon and Goldstone boson exchange on the dibaryon mass and decay width has been studied in the framework of the quark delocalization and colour screening model. The effective S-D wave transition interactions induced by gluon and Goldstone boson exchanges decrease quickly with the increasing channel strangeness, and there is no six-quark state in the light flavour world, which can become a bound one by the help of these tensor interactions, except for the deuteron. The K and η meson exchange effect has been shown to be negligible after a short-range truncation in this model approach. The partial D-wave decay widths, from the NΩ state to the ΛΞ final states of spins 0 and 1, are 20.7keV and 63.1keV respectively. This is a very narrow dibaryon resonance, that might be detected in the relativistic heavy ion reaction by the existing RHIC detectors through the reconstruction of the ΛΞ vertex mass and by the future COMPAS detector at CERN and the FAIR project in Germany.

We study medium modifications of the nucleon electromagnetic form factors in the vector meson dominance model. The in-medium vector meson masses are taken from a chiral SU(3) model. We find that the electric and magnetic form factors of the bound nucleon deviate considerably from those of the free nucleon. Our results are comparable to the results from the quark meson coupling model approach and are consistent with present experimental limits.

Within the Kobayashi--Maskawa mechanism of electroweak interaction and using the recent measured mass of the top quark, we estimate the neutron electric dipole moment (NEDM) via the diquark electroweak interaction. The resulting moment is about 10^-30 ecm. The actual upper bound on the NEDM is 6.3× 10^-26 ecm and it can reach the value 5×10^-28 ecm predicted by experiments in recent years.

Various measures for the dynamical event mean transverse momentum fluctuation are compared with the real dynamical fluctuation using a Monte Carlo model. The variance calculated from the G-moments can reproduce the dynamical variance well, while those obtained by subtraction procedures are approximate measures for not very low multiplicity. Ф_pt, proposed by Gazdzicki M and Mrowczynski S [Z.Phys.C 54(1992)127], can also serve as an approximate measure after being divided by the square root of mean multiplicity.

Based on the Dyson--Schwinger equations (DSEs) in the `rainbow' approximation, we investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, we calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ ²_u,d = 0.7GeV² for u,d quarks, and λ ²_s = 1.6GeV² for s quark. Our theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions.

The nature of signature inversion in the πg9/2^vh11/2 bands of odd--odd^98,102Rh nuclei is studied. Calculations are performed by using a triaxial rotor plus two-quasiparticle model and are compared with the experimentally observed signature inversions. The calculations reproduce well the observations and suggest that, in these bands, the signature inversion can be interpreted mainly as a competition between the Coriolis and the proton--neutron residual interactions in low K space. The triaxiality applied in the Hamiltonian enlarges the amplitudes of high spin signature zigzags at small triaxial deformation and might push the signature inversion point to higher spin at large triaxial deformation.

Occurrence of superdeformed (SD) shape from the relationship between the collective rotation and the pairing correlations is investigated in the relativistic mean field theory framework. It is found that pairing correlation plays an important role in the occurrence of SD shape. It is also shown that the SD band of ⁶⁶Zn is more difficult to be observed than that of⁶⁰ Zn experimentally.

An effective model is used to study the equation of state (EOS) of strange hadronic matter with nucleons,Λ-hyperons and Ξ-hyperons. In the calculation, a newest weak hyperon--hyperon (Y--Y) interaction deduced from the recent observation [Phys. Rev. Lett. 87(2001)212502-1] of a ⁶_ΛΛHe double hypernucleus is adopted.The calculated results are compared to those calculated with the strong Y-Y interaction used in previous studies.

The energy loss effect in nuclear matter, which is another nuclear effect apart from the nuclear effects on the parton distribution as in the deep inelastic scattering process, can be measured best by the nuclear dependence of the high energy nuclear Drell-Yan process.By means of the quark energy loss parametrization given in literature and the nuclear parton distribution extracted only with lepton-nucleus deep inelastic scattering experimental data, measured Drell-Yan production cross sections are analysed for 800-GeV protons incident on a variety of nuclear targets from FNAL E866. The average energy loss of quarks are given by fitting the Fe/Be and W/Be Drell-Yan cross section ratios versus the incident parton momentum fraction.

We investigate the effects of target deformation on the synthesis of superheavy nucleus ²⁸³112 in the framework of the extra-push model. Our results show that the cross sections of the 3n evaporation residue in the ⁴⁸Ca+²³⁸U reaction for the case of β₂ = 0.275 are several times larger than those of β₂ = 0. Meanwhile, the peak position of ER excitation function in the case of the deformed target is shifted to lower energy as compared to that of the spherical target.

We studied the effect of Coulomb interaction on the isospin fractionation in the intermediate energy heavy ion collisions by using the isospin-dependent quantum molecular dynamics model. The calculated results show that Coulomb interaction induces the reduction of the isospin fractionation process with the evolutions of neutron-proton ratio and mass of system. Because Coulomb interaction is repulsive for the proton, more binding protons become free, which produces the neutron-poor gas phase and neutron-rich liquid phase, compared to the neutron-proton ratio of the system. The isospin fractionation degree is weakened by the Coulomb term. In contrast, the symmetry potential is repulsive for neutrons and attractive for protons in the neutron-rich system, and then the binding neutrons more than the protons become free, which produces a neutron-rich gas phase and neutron-poor liquid phase, so that the isospin fractionation degree is increased. The competition between the effects from the Coulomb interaction and the symmetry potential induces the reduction of the isospin fractionation degree for all the system masses. The properties for the sensitive dependence of isospin fractionation degree on the symmetry potential and weak dependence on the nucleon- nucleon cross section are preserved for all the neutron-rich systems.

Using the relativistic quantum molecular dynamics model, we study the influence of multiple scattering on the result of two-pion correlation measurements. The scales of pion spatial distribution are larger at thermal freeze-out than at chemical freeze-out. By varying the value of the parameter of cross section from 0 to 90 mb, we find that the sizes of pion source measured by two-particle correlation functions are almost independent of the parameter of cross section. However, λ parameters are sensitive to the parameter of cross section.

We report production of hyperpolarized ¹²⁹Xe gas via spin-exchange with optically pumped Cs atoms at the D₂ line, achieved at low magnetic field in a flow system and in the absence of nitrogen gas. The nuclear spin polarization of hyperpolarized ¹²⁹Xe gas is enhanced by a factor of 10000 compared to that without optical pumping under the same condition, which corresponds to polarization of about 2.66%. Due to the high spin polarization, the radiation damping of hyperpolarized ¹²⁹Xe gas has also been observed in the flow system.

We propose a novel controllable double-well magneto-optical trap (MOT) by using a square current-carrying wire and a bias magnetic field. The spatial distributions of the magnetic fields and their gradients are calculated, and the results show that the proposed trap has double magnetic wells with two centres of zero magnetic field and can be continuously evolved as a single-well trap by reducing the current in the wire or increasing the bias field, which can be used to realize a controllable double-well MOT, even to prepare one- and two-dimensional arrays of magneto-optical lattices on the surface of an atom chip. We also estimate the number (～10⁷) and temperature ( ～260μ K) of trapped cold atoms in our MOT.

An algebraic Hamiltonian, which in a limit can be reduced to an extended local mode model by Law and Duncan, is proposed to describe both stretching and bending vibrational energy levels of polyatomic molecules, where Fermi resonances between the stretches and the bends are considered. The Hamiltonian is used to study the vibrational spectra of stibine (SbH₃). A comparison with the extended local mode model is made. Results of fitting the experimental data show that the algebraic Hamiltonian reproduces the observed values better than the extended local mode model.

Single-electron detachment (SED) cross sections for Cr^- and Ti^- in collision with N₂ have been obtained in the energy region of 10-30keV, for the first time to our knowledge. In the present energy range, the magnitude of the Cr^-+N₂ and Fe^-+N₂ SED cross sections is larger than that of Cu^-+N₂. It is also found that the cross sections for Cr^- and Ti^- in collisions with N₂ exhibit different dependences on anion impact velocity from that of Cu^-

We present an improved confocal readout system to achieve three-dimensional superresolution. This improved system is based on a combination of two different annular binary phase filters, the one designed for increasing the transverse superresolution and the other for achieving axial superresolution. By adjusting the pupil parameters, each pupil can be well designed. The simulation results show that with this improved system, the area of the central lobe of the three-dimensional point spread function of the read optics is greatly reduced. Moreover, the side-lobes are extinguished.

We investigate the generation of quantum interference induced by spontaneous emission from two transitions of a V-type three-level atom embedded between two parallel plates (one or both the plates have infinite permeability, i.e.μ→∞). The result shows that, due to the anisotropy of vacuum, quantum interference still exists although the two dipole matrix elements of the atom are orthogonal to each other. When the atom is located very close to one of the plates, the quantum interference effect is particularly prominent. The strength of quantum interference displays oscillating behaviour with the position of the atom. With the increase of the distance between the plates, the oscillation becomes dense.

Using Schrödinger-Maxwell formalism, we propose and analyse a cw four-wave mixing (FWM) scheme for the generation of coherent light in a five-level double-Λ atomic system based on electromagnetically induced transparency. We derive the corresponding explicit analytical expressions for the generated FWM field. The influence of hyperfine sublevel on the amplitude of the generated FWM field is predicted in detail. We also give a brief discussion on the experimental realization of the proposed scheme.

With trapped atoms, we propose an experimental scheme to implement entanglement swapping based on adiabatic passage and the detection of cavity decay. This scheme is inherently robust to diverse sources of noise, such as atomic spontaneous emission, or detector inefficiency. The advantages make it realizable with the current experimental technology.

We report the generation of ultrashort pulses in ytterbium-doped fibre oscillator emitting around 1.05μm at a repetition rate of 17.6MHz. A diode laser with single silica fibre at 976nm pumps the ytterbium fibre laser, the all-fibre picosecond pulsed oscillator has excellent stability and compact size, and freedom from misalignment. After amplifying, pulse energy of 3.4nJ and an average power of 60mW are obtained. The compression is obtained with a grating pair out of the cavity. The compressor produces 307fs with the peak power 5.47kW. A practical fibre-based source with good performance is thus demonstrated.

A maximum of 9.9W cw TEM₀₀ output at 532nm laser has been obtained by intracavity frequency doubling with LBO in laser-diode single-end-pumped Nd:YVO₄. The Nd:YVO₄/LBO green laser has a simple three-mirror V-fold cavity structure. The optical-optical conversion efficiency was 34.8%. Based on the equation of thermal conduction, a general solution for the laser-crystal interior temperature distribution is obtained by the semi-analytical thermal analysis method. Using the software system, the cavity parameters have been optimized according to the stability condition and the astigmatic compensation principle. The astigmatism in the cavity has been effectively controlled and the resonator was insensitive to the thermal lens in the Nd:YVO₄ crystal.

We developed a novel photorefractive (PR) polymer PVK-PBA:DR1:TNF, and its film sample was prepared with outstanding performance by using the method of combination of vacuum saturated vapour resolving with vacuum hot-pressing. The sample exhibits distinctive PR properties with the two-beam coupling coefficient up to 140cm^-1 and four-wave mixing (FWM) diffraction efficiency above 1.5% in the absence of applied external electric field. The designed experiments, including measurements of the second-order nonlinear coefficient and birefringence as well as the relationship between the diffraction efficiencies of the FWM and the external bias field, were performed to understand the underlying mechanism, because this phenomenon cannot be explained by the conventional PR theories. It is presented that because of its high orientational mobility and large dipole moment, the polymer produces the photovoltaic effect under the irradiation of laser to induce a space-charge field so as to engender the PR effect under zero or low external fields. A model based on the assumption was established and the simulation agrees well with the experimental results.

We present a new method to realize large bandwidth optical limiting using Kerr nonlinearity doped one-dimensional coupled cavity optical waveguides (CCOWs). When the incident intensity is weak, the structure is a perfect CCOW that supports a high transmission band. When the intensity is increased, the Kerr effects change the refractive index of the Kerr cavity which results in a large decrease of transmission coefficients in the whole band. We numerically analyse the limiter using the nonlinear transfer matrix method and nonlinear finite difference in time domain method. Optical limiting effects are observed in the whole transmission band, and optimization methods are also discussed.

The photonic crystal fibre with asymmetric dual cores is shown to attain strongly nonreciprocal coupling of the lightwave propagating along the fibre, for the first time to our knowledge. It is found that the coupling properties can be quite different when the incident position is changed. This kind of fibre could have potential for unidirectional coupler applications in fibre-optic local and metropolitan area networks. We also examine the polarization and wavelength dependence of the coupling nonreciprocity in the asymmetric dual-core photonic crystal fibres.

The scattering matrix S describing photonic crystal slabs is formulated. A new method is introduced to solve the eigenfrequency ω for a given Bloch wave vector K from the equation det S^-1 ( ω ,K)=0. Using this method, we can obtain not only guided modes but also leaky modes in photonic crystal slabs with a higher-frequency resolution than that of the FDTD method.

We report multi-mode coupling in long-period fibre gratings (LPFGs). The analytical solution to three-mode coupling equations is presented for the first time. A 3×3 transmission matrix is attained and can be used to calculate the transmission spectra of nonuniform gratings in a way much faster than direct numerical integration. It is shown that when the resonant wavelengths of cladding modes are far from each other, two-mode coupling model can still be used. Otherwise we can only choose a multi-mode coupling model. Theoretically fitting of the result from the multi-mode coupling equations agrees well with the experimental one for mechanically-induced LPFGs.

The optically polished LiNbO₃ crystal was implanted with 3.0MeV nickel ions to a dose of 8×10¹⁴ ions/cm². The implanted sample was orderly annealed at different temperatures for different times in air ambient. The waveguide properties before and after annealing were investigated. Dark modes were observed by the prism coupling technique. The reconstructed refractive index profiles were obtained with the reflectivity calculation method. With the fibre probe technique, the attenuation of the Ni-implanted barrier-confined waveguide was measured for the first time. The waveguide loss was reduced from 1.65dB/cm to 1.19dB/cm when annealing was at 300°C for 30min. With the annealing temperature increasing to 370°C , only fewer broad dark modes were found. It is indicated that the lattice damage by implantation began to resume under this annealing condition. After annealing at 380°C for 60min, all the dark modes disappeared.

Based on the principle of the graded-index multimode interference (MMI), an 8×8 MMI optical coupler is designed and fabricated by using K⁺- Na⁺ ion-exchange technique on a BK₇ glass substrate. The performance of the device is tested. The output of optical coupler has a high uniformity of approximately 0.72dB.

We propose a novel approach to fabricate an array of three-dimensional waveguides in lithium niobate by employing illuminations of a pair of mutually coherent or incoherent two-beam interference patterns. Adjusting periods of the patterns and the angle between the grating vectors of the two patterns, we find that arrays of square, rectangular or parallelogrammic waveguides can be created. An array of rectangular waveguides is demonstrated in an iron doped lithium niobate by the double exposures of two-beam interference patterns with different orientations. The measured index distribution and the guiding test results show that the waveguide array is successfully fabricated.

Based on elongation and shear microstrains between the doublet particles, we present the dynamic scaling equations of plane wave propagation in a cubic-tetrahedral assembly (lattice type H₄) in accordance with the formalism of doublet mechanics (DM). The relations between the micro-moduli of DM constitutions and the macro-parameters of the Cosserat continuum model are obtained by a mapping process and a non-scale approximation of the DM model. With multi-scale characteristics, the frequency dispersion curves from DM reflect the effect of granule inhomogeneity and the anisotropic nature of the micro-structure on the wave propagation in the H₄ medium.

Instability is the main challenge in simulating dynamic phase transitions. For a van der Waals fluid, we introduce low order dissipative mechanisms with discrete Bhatnagar-Gross-Krook (BGK) models, including a relaxation model. In one and higher space dimensions, numerical results demonstrate the complexities of dynamics. While eventually a good separation of phases is reached, interesting wave patterns are observed at an earlier stage.

A simple geometry model for tortuosity of flow path in porous media is proposed based on the assumption that some particles in a porous medium are unrestrictedly overlapped and the others are not. The proposed model is expressed as a function of porosity and there is no empirical constant in this model. The model predictions are compared with those from available correlations obtained numerically and experimentally, both of which are in agreement with each other. The present model can also give the tortuosity with a good approximation near the percolation threshold. The validity of the present tortuosity model is thus verified.

The structure of an electronegative plasma sheath in an oblique magnetic field is investigated with a fluid model. We assume the system consists of hot electrons and negative ions as well as cold positive ions. Densities of particles and distributions of the spacious potential in various states of magnetic field are studied. The result shows that the existence of magnetic field and negative ions has great effects on the plasma sheath structures. In addition, the effects of negative ion density and temperature on the structure of the electronegative plasma sheath are discussed.

A new kind of instability driven by the magnetic field gradient and curvature (MFGC) in toroidal plasmas is presented. It is found that the MFGC drift modes possess finite growth rates even if the plasma pressure gradient vanishes. In addition, the effects of plasma pressure gradient and safety factor on the MFGC modes have been analysed numerically.

Edge plasma parameters, including electron temperature T_e, density n_e, plasma potential Ф_p , radial electric field E_r and the corresponding fluctuations in the Sino-United Spherical Tokamak, have been systematically measured with Langmuir probe arrays. Wavenumber spectrum analyses show that edge fluctuations have a radial propagation character of the drift wave turbulence, with a characteristic radial phase velocity v_phr ～ 0.7 km.s^-1 in the scrape-off layer and vsuB>phr ～ 0.9-1.4km.s^-1 in the plasma edge.

The stochastic ripple diffusion is investigated in a realistic reversed magnetic shear discharge. Rippled field produces variations in the velocity of trapped particles leading to excursion of the tip position for successive banana bounces. When the excursion is large enough, the trapped energetic particles are lost rapidly via stochastic banana diffusion. The ripple diffusion of fast ions produced during the neutral beam injection is calculated by assuming that the trapped ions are lost if their turning points are in regions where the ripple exceeds a threshold for the stochastic ripple loss. As the safety factor is of higher value inside the reversed magnetic shear plasma, the ripple loss in a modelled reversed magnetic shear discharge of HL-2A is much stronger than that in a non-RS discharge.

The nitrogen 1s near-edge x-ray absorption fine structure (NEXAFS) spectra of the N₂O adsorbed on the Cu(100) surface have been studied by multiple-scattering cluster (MSC) and self-consistent field DV-X_αmethods. It is shown that the N₂O molecule is adsorbed on the hollow site with the adsorption height h = 3.0±0.1A. The MSC calculation confirmed by a DV-X_α analysis has revealed the physical cause of the weak feature in the NEXAFS spectra mentioned above, which originates from the $1s$ core electrons of the centre and terminal nitrogen atoms transiting into the unoccupied σ^* orbital of the N₂O molecule.

The crystal nucleation and growth mechanism during the formation of Ag_42.4Cu_21.6Sb₃₆ ternary eutectic are investigated under substantial undercooling conditions. The x-ray diffraction analysis shows that the solidified eutectic phases are not involved (Ag) within a wide undercooling range of 6-114K. This indicates that under high undercooling condition, the phase constitution of Ag-Cu-Sb eutectic is different from that in the equilibrium phase diagram. With the increase of undercooling, the crystalline morphology of Ag_42.4Cu_x21.6Sb₃₆ alloy transforms from the mixed structure of primary θ(Cu₂Sb), two pseudobinary eutectics and (ε+θ+Sb) ternary eutectic into a unique (ε+θ+Sb) ternary eutectic. The calculated results indicate that θ(Cu₂Sb) is the leading nucleating phase among the three eutectic phases. In addition, the growth morphology of primary ε(Ag₃Sb) compound in Ag₆₀Cu₆Sb₃₄ alloy exhibits the characteristics of solid solution and its orthorhombic dendrite grows along the <111> directions.

We investigate plastic deformation of Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 bulk metallic glass using depth sensing nanoindentation. Numerous serrations in the load-displacement curves during indentation, shear bands and pile-ups around the indent were observed. The results revealed that the serrated
plastic flow behaviour in this alloy depends strongly on the indentation strain rate.

The lattice structures around one lead vacancy V^2-_Pb in PbWO₄ are studied within the framework of the full-relativistic density functional theory. Using the conjugate gradient method, we optimize the geometry of the ions around V^2-_Pb by moving the ions within the sub-cell until specified tolerance is satisfied. We obtain the geometric positions of ions around V^2-_Pb after optimization. The calculated results indicate that there would be local lattice distortion caused by the existence of V^2-_Pb. The electronic structures of both the optimized and pre-optimized PWO containing V^2-_Pb have been calculated. The density of states of the distorted PWO indicates that the energy gap between the 2p state of O^2- and the 5d state of W⁶⁺ is 3.90eV, which shows that the distorted W-O tetrahedron may be the 420nm luminescence centre.

Silicon-on-insulating multi-layer (SOIM) materials were fabricated by co-implantation of oxygen and nitrogen ions with different energies and doses. The multilayer microstructure was investigated by cross-sectional transmission electron microscopy. P-channel metal--oxide--semiconductor (PMOS) transistors and metal--semiconductor--insulator--semiconductor (MSIS) capacitors were produced by these materials. After the irradiated total dose reaches 3×10⁵ rad (Si), the threshold voltage of the SOIM-based PMOS transistor only shifts 0.07V, while thin silicon-on-insulating buried-oxide SIMOX-based PMOS transistors have a shift of 1.2V, where SIMOX represents the separated by implanted oxygen. The difference of capacitance of the SOIM-based MSIS capacitors before and after irradiation is less than that of the thin-box SIMOX-based MSIS capacitor. The results suggest that the SOIM materials have a more remarkable irradiation tolerance of total dose effect, compared to the thin-buried-oxide SIMOX materials.

We study the structures of Ag adatom clusters supported on the metal Ag(111) surface using the genetic algorithm (GA). The atomic interactions are modelled by the surface-embedded-atom method. The lowest-energy structures of adatom clusters with sizes n=3-20 are obtained, in which n=7, 10, 12, 14, 16, 19 are the magic numbers. Furthermore, we give a series of structures with energies close to the lowest energy (the lower-energy isomers), and the structure features are studied in detail. Except for some magic clusters and small clusters, every configuration of adatom clusters generally has two distinct adsorption ways, so the isomers always appear in pairs.

Reflection high energy electron diffraction and scanning tunnelling microscopy (STM) are used to investigate the structure and morphology of Al films deposited on Si(111)-7×7 surface at room temperature. The films are polycrystalline, made up of (100) and (111) oriented islands, which primarily result from the interface elastic effect and free surface energies of the Al (100) and (111) surfaces.

Electronic structures and magnetic properties of CoN, NiN and CuN in zinc-blende, rocksalt, nickel arsenide, wurtzite and caesium chloride structures have been calculated by employing a first-principle full-potential linearized muffin-tin orbital method with the generalized gradient approximation. The results reveal that the zinc-blende structure is the ground state for the three mononitrides. The Stoner criterion indicates that the rocksalt and caesium chloride structures of CoN may have magnetic ordering, but the magnetic ordered phases are not stable. Compared with the result calculated with the local density approximation, the equilibrium lattice constant of CoN with the generalized gradient approximation is in better agreement with the experimental results.

In the presence of an electric field perpendicular to the axes of the wire, the binding energy of shallow donor impurity in finite square quantum well wires is calculated. For different impurity positions and aspect ratios of the wires, we investigate the Stark shift of the $1s$-like state energy of the impurity by expanding the wavefunction into a two-dimensional Fourier series and by using the variational scheme. It is found that the electric field breaks down the degeneracy of the states for impurities symmetrically positioned within the structure and leads to red-shift or blue-shift of the impurity Stark energy, respectively. Furthermore, the scaling rule of the binding energy will not be valid for the square quantum well wire under the applied electric field.

Based on the effective-mass approximation, exciton states confined in wurtzite In_xGa_1-xN/GaN strained coupled quantum dots (QDs) are investigated, in which the strong built-in electric field effects due to the piezoelectricity and spontaneous polarization are considered. We find that the barrier thickness between the two QDs has a considerable influence on the exciton states and the interband optical transitions. If the barrier thickness is increased, the exciton binding energy is decreased, the emission wavelength is increased, and the electron--hole recombination rate is obviously reduced. Our theoretical results are in qualitative agreement with the experimental measurements.

The effects of annealing temperature on TbFe films prepared by dc magnetron sputtering were discussed. X-ray diffraction patterns indicate that these polycrystalline films consisting mainly of α-Fe and TbFe₂ lave phase with grain sizes less than 25nm can be obtained by a rapid cycle annealing process. Grain sizes can be controlled by varying annealing temperatures. Film hysteresis loop studies show that annealing treatment can improve TbFe film in-plane soft magnetic performances. Magnetic domain structures explored by a magnetic force microscopy show that in the as-deposited films, maze domain structures exist, hence it possesses perpendicular anisotropy and larger anisotropic constant K_u. No domains are observed when annealing temperature is lower than 400°C. However, maze domain structures appear again when annealing temperature is higher than 400°C. Two maxima of magnetostrictive coefficients are obtained at annealing temperatures of 300°C and 500°C in the presence of a 40kA.m^-1 external magnetic field.

(Pt/Co)₅/Ru/(Co/Pt)₅ films with different Ru thicknesses were prepared by magnetron sputtering. Oscillatory behaviour of effective perpendicular anisotropy and remanence in the (Pt/Co)₅/Ru/(Co/Pt)₅ films as a function of the thickness of Ru has been first observed, from which we can obtain the conclusion that the synthetic spin in the (Pt/Co)₅/Ru/(Co/Pt)₅ films rotates from the vertical direction to the in-plane one periodically with the change of the thickness of the spacer layer of Ru. The oscillatory period is about two atomic layers of Ru and different from the long and short oscillatory periods of the interlayer antiferromagnetic coupling in Co/Ru/Co, Co/Cu/Co, and Fe/Cr/Fe, etc.

A systematic study based on an ab initio calculation within a local spin density approximation is applied to material design of GaAs- and GaP-base doped by 3d transition metals. It is found that the ferromagnetic (FM) state is ready to achieve by V-, Cr- and Mn-doped GaP and GaAs. (Ga, Cr)P and (Ga, Cr)As are the most promising candidates for high Curie temperature (above room temperature). In order to increase the Curie temperature, the Mg co-doped method is applied to (Ga, Mn)P and (Ga, Mn)As. By the co-doping, the energy difference between the antiferromagnetic state and the FM state is enlarged, and the partial density of states of 3d-Mn at Fermi energy E_F is increased, which increases the Curie temperature of the diluted magnetic semiconductors. By this co-doping, the anti-bonding state of 3d-Mn is pushed up to a higher region, hence the 3d electrons are more delocalized and itinerated. This makes double exchange dominant, and (Ga, Mn)P and (Ga, Mn)As more stable.

By using the pump--probe technique, the femtosecond (fs) time-resolved absorption dynamics of oxyhaemoglobin (oxy Hb) in living erythrocytes was studied for the first time to our knowledge. The changing course of erythrocyte absorption at 400nm was found to be composed of three exponential decay components with the time constants of 200±28fs, 3.60±0.14ps and 215±21ps respectively, which are consistent with those of oxy Hb water solution measured in the same way, indicating that the fast process (less than 1ns) of photo-induced response in erythrocytes was as the same as that in oxy Hb aqueous solution. These three decay components were assigned to the transitions from excited states of unligated haemoglobin (Hb_I^*, Hb_II^*) and fast geminate recombination of O₂ and Hb, respectively.

Room-temperature P-band emission induced by an exciton--exciton collision process was observed in ZnO micro-rods. Both temperature- and excitation-intensity-dependent photoluminescence (PL) measurements were conducted. The excitation-intensity-dependent measurement illustrated that the P-band emission could occur at far lower excitation intensity than that reported in the literature. Higher-order transitions were also observed at the excitation intensity of 7.1kW/cm² or above. The temperature-dependent PL showed that the P-band emission process was thermally activated. It is suggested that both the density and activity of free excitons played important roles in the exciton--exciton collision process.

We investigate optical near-field distributions of the unconventional C-apertures and the conventional square apertures in preliminary experiment with an aperture scanning near-field optical microscope. These nano-apertures are fabricated in Au film on a glass substrate with focused ion beam technology. The experimental results indicate the uptrend of output light intensity that a C-aperture enables the intensity maximum to increase at least 10 times more than a square aperture with same unit length. The measured near-field light spot sizes of C-aperture and square aperture with 200-nm unit length are 439nm×500nm and 245nm×216nm, respectively.

Using the temperature gradient method under high pressure and high temperature, we investigate the dependence of growing high-quality gem diamond crystals on the growth rates. It is found that the lower the growth rate of gem diamond crystals, the larger the temperature range of growing high-quality gem diamond crystals, and the easier the control of temperature. In particular, when growing gem diamonds under a very-low growth rate, the temperature range of growing high-quality gem diamonds can extend from a low-temperature pure {100} growth region to {100}+{111} growth regions, and finally to a high-temperature only-{111}-growth region. When growing gem diamonds under a high growth rate, some metal inclusions in the growing diamonds always exist near the seeds, no matter whether the growth temperature is high or low. This result is not in agreement with the result of Sumitomo Electric Corporation in Japan.

A crush criterion and a simplified post-crush process for spherical grains are introduced into the traditional distinct element model (DEM). The crush criterion is based on Hertzian contact, and it indicates a negative relation between critical force F_cr and radius R via F_cr∝R^-3/2. Effects of grain crush on deformation pattern and statistical features of crush evolution for samples under uniaxial strain load are intensively investigated. Influences of maximum crush times and particle size distribution (PSD) are also discussed. It is found that: (1) Grain crush will blur the localization of deformation. (2) Crush is prone to occur in larger grains, due to force concentration and lower critical force F_cr for larger grains. (3) Grain crush only temporarily reduces contact force, which results in the most rapid increase of the number of grains with maximum crush time.

The magnetic microstructures of two Dy-Al substituted sintered Nd-Fe-B magnets with the different nominal compositions of Nd_12.2Dy_0.6Fe_80.4Al_0.7B₆(at.%) (composition-A, C-A) and Nd_13.7Dy_0.6Fe_78.8Al_0.7B_6.2(at.%) (composition-B, C-B) prepared by strip casting technique have been revealed by using a magnetic force microscope. The magnetic properties of sintered C-B magnets are worse than that of C-A sintered magnets. In particular, the value of density products (BH)_max for sintered C-A magnets is about 32% higher than that of C-B magnets, which is reflected by their quite different magnetic microstructures. We believe that for the C-B samples, the inappropriate composition and thus the redundant Nd₂Fe₁₇(B) phase of the casting strips make its final magnetic microstructures worse than the C-A, and then deteriorates the performance of the C-B magnets.

We propose a mathematical model to analyse the membrane tether formation process on a cell surface with reservoir. Based on the experimental results, the membrane reservoir density of breast cancer cell was obtained, ρ = 8.02. The membrane surface viscosity between membrane and environment η is 0.021(pN.s/μm³), and the static force F₀ = 5.71pN.

We simulate a relaxation process of a polaron in polymer after photo excitation, and a new state is realized by means of proper excitation. The original lattice configuration of the polaron splits into two symmetrical peaks, and consequently a double-well potential is formed, where the wavefunctions of electron localized in these two wells are entangled. Thus, this process provides a method to generate the Schrödinger cat state. According to the dynamical process of the lattice configuration, the relaxation time of splitting is about 150fs.

A stochastic calcium oscillation model based on the minimal calcium oscillation model is investigated by numerical computation. When the extracellular stimulation is sub-threshold and random, the oscillations of cytosolic calcium show complex behaviour: a bursting-like phenomenon induced by noise, that is, the phase of glomerate spikes are separated by phase of quiescence (but fluctuations in the baseline values of calcium with small amplitude during the silent phase), in a pattern that occurs at irregular intervals. By using the histogram of interspike intervals of calcium concentration spikes, it is found that the noise-induced coherence resonance phenomenon occurs at the cellular level.

We discuss the evolution of the scale factor in a higher-dimensional cosmological model in which the cosmological constant is given by the scalar arisen by the contraction of the stress-energy tensor.

We have used the Hubble Space Telescope observations to measure proper motion of the globular cluster NGC 6656 (M22) with respect to the background bulge stars and its internal velocity dispersion profile. Based on the proper motion of the cluster, its space velocity (II,,W) = (184±3,209±14, 132±15)kms^-1 and galactic orbit are also obtained. The central velocity dispersion in radial and tangential components of the internal motion of cluster stars is 16.99kms^-1. We derive the mass-to-light ratio M/L_v～3.3±0.2, which is relatively higher than the previous results.

The first mapping observations in ¹²CO J=2-1 and ¹²CO J=1-0 lines were made towards molecular cloud associated with IRAS 07028-1100. The results show a mono-polar outflow (primarily blueshifted component) near IRAS 07028-1100, which suggests that star formation is occurring in this region. On the basis of the MSX (Midcourse Space Experiment) band-A image, molecular cloud core contours, NVSS data and IRAS data, we identify IRAS 07028-1100 as an embedded young intermediate-mass star. According to the 2MASS data, we suggest a sequential star formation in the infrared cluster associated with IRAS 07028-1100.