It is shown that the differential form of Friedmann equations of Friedman--Robertson--Walker (FRW) universe can be recast as a similar form of the first law T_hdS_h = dE + WdV of thermodynamics at the apparent horizon of FRW universe filled with the viscous fluid. It is also shown that by employing the general expression of temperature associated with the apparent horizon of an FRW universe and assumed that the temperature T_m of the energy inside the apparent horizon is proportional to the horizon temperature T_m= bT_h, we are able to show that the generalized second law of thermodynamics holds in the Einstein gravity provided T_h-T_m/r^~_A ≤(ρ+P^~).

An analytical method is proposed to evaluate the Hugoniot parameters of preheated metallic materials by relating to its principal Hugoniot. Modelling calculations for 1100 Al, Cu and Ta show that the preheating lowers to a certain extent the shock impedance and the degree of lowering the shock impedance increases with increasing preheating temperature. The Hugoniots of 6061-T6 Al and TC4 preheated flyers at known preheating temperatures are evaluated, and are utilized to calculate the particle velocity and shock pressure using the impedance-match method based on the measured shock wave velocity and impact velocity reported in Z pinch-driven and three-stage gun-driven Hugoniot experiments. The presented method allows a reasonable evaluation for Hugoniot of the preheated metallic flyers.

The relationship between the dispersion capability and the temperature of argon arc plasma at 1 atm is deduced in view of the plasma's refractive index equation. The results indicate that argon arc plasma has a normal dispersion and its dispersion capability is nonlinear to the plasma's temperature in a wide range of temperature and wavelength region. According to the results of numerical calculation, the preferred optical methods are believed to be suitable for the diagnosis of argon arc plasma in different temperature regions.

We have investigated vacuum Rabi oscillation of an atom coupled with single-mode cavity field exactly, and compared the results with that of the Jaynes--Cummings (J-C) model. The results show that for resonant case, there is no Rabi oscillation for an atom. For small detuning and weak coupling case, the probability for the atom in excited state oscillates against time with different frequencies and amplitudes from that of the J-C model. It exhibits that the counter-rotating wave interaction could significantly effect the dynamic behaviour of the atom, even under the condition in which the RWA is considered to be justified.

A continuously tunable erbium-doped fibre laser (TEDFL) based on tunable fibre Bragger grating (TFBG) and a three-port optical circulator (OC) is proposed and demonstrated. The OC acts as a 100%-reflective mirror. A strain-induced uniform fibre Bragger grating (FBG) which functions as a partial-reflecting mirror is implemented in the linear cavity. By applying axial strain onto the TFBG, a continuously tunable lasing output can be realized. The wavelength tuning range covers approximately 7.00nm in C band (from 1543.6161 to 1550.3307nm). The side mode suppression ratio (SMSR) is better than 50dB, and the 3dB bandwidth of the laser is less than 0.01nm. Moreover, an array waveguide grating (AWG) is inserted into the cavity for wavelength preselecting, and a 50km transmission experiment was performed using our TEDFL at a 10Gb/s modulation rate.

Based on the first-principles plane-wave basis pseudopotential calculations, we investigate mechanical properties and electronic structures of the hardest known oxide, cotunnite TiO₂. The calculated results show that cotunnite TiO₂ has the highest bulk modulus (348 GPa) and hardness (32GPa) among the high-pressure phases of TiO₂, but its mechanical properties are not superior to those of c-BN. Moreover, the high hardness of cotunnite TiO₂ can be understood from both the dense crystal structure (high valence electron density and short bond lengths) and the unusual mixtures of covalent and ionic bonding of Ti--O.

We demonstrate that thin films with micro/nanometre controllable morphology can be fabricated by the glancing angle deposition (GLAD) technique which is a physical vapour deposition technique. In this technique, there are parameters which determine the morphology of the thin films: the incident angle, ratio of the deposition rate with respect to the substrate rotation rate, nature of the material being deposited, etc. We fabricate the morphology of column, pillar, helices, zigzag and study the parameters which determine morphology by given some examples of SEM.

We present a theoretical study on the composition dependence of the surface phonon polariton (SPP) mode in wurtzite structure α-In_xGa_1-xN ternary alloy over the whole composition range. The SPP modes are obtained by the theoretical simulations by means of an anisotropy model. The results reveal that the SPP mode of α-In_xGa_1-xN semiconductors exhibits one-mode behaviour. From these data, composition dependence of the SPP mode with bowing parameter of -28.9cm^-1 is theoretically obtained..

We introduce a one-dimensional spin injection structure comprising a ferromagnetic metal and a nondegenerate organic semiconductor to model electric current polarizations. With this model we analyse spin Coulomb dragging (SCD) effects on the polarization under various electric fields, interface and conductivity conditions. The results show that the SCD inhibits the current polarization. Thus the SCD inhibition should be well considered for accurate evaluation of current polarization in the design of organic spin devices.

We re-examine the classical one-dimensional transmission grating to explain the enhanced transmission in the surface impedance approximation. The nearly zero transmission and extraordinary transmission phenomena related to the surface plasmon are presented by analysing the scattering amplitude of waveguide mode at the output surface of grating. It is revealed that the transmission peaks are related to the Fabry-Perot factor and the interaction of surface plasmon and other diffractive orders.

A Schrödinger equation is solved numerically for a barrier in a quantum well and a quantum well in another well structure by the transfer matrix technique. Effect of structure parameters on the transmission probabilities is investigated in detail. The results suggest that symmetry plays an important role in the coupling effect between the quantum wells. The relationship between the width of the inner well and the resonant energy levels in well-in-well structures is also studied. It is found that the ground state energy and the second resonant energy decrease with increasing width of the inner well, while the first resonant energy remains constant.

We apply the effective-medium theory to a multi-component mixture system, by which the effective longitudinal and Hall conductivities can be calculated. We find that there is more than one threshold in the multi-component mixture, and the maximum number of thresholds is one less than the component number. Further, the thresholds are mainly dependent on the relative volume ratio of the components when the conductivity ratios between any two components are far larger or smaller than one.

High resolution angle-resolved photoemission measurements have been carried out to study the superconducting gap in the (Ba_0.6K_0.4)Fe₂As₂ superconductor with T_c=35 K. Two hole-like Fermi surface sheets around the Γ point exhibit different superconducting gaps. The inner Fermi surface sheet shows larger (10~12 meV) and slightly momentum-dependent gap while the outer one has smaller (7~8meV) and nearly isotropic gap. The lack of gap node in both Fermi surface sheets favours s-wave superconducting gap symmetry. Superconducting gap opening is also observed at the M(π,π) point. The two Fermi surface spots near the M point are gapped below T_c but the gap persists above T_c. The rich and detailed superconducting gap information will provide key insights and constraints in understanding pairing mechanism in the iron-based superconductors.

The piezoelectric properties of the (KCe)-substituted sodium bismuth titanate (Na_0.5Bi_4.5Ti₄O₁₅, NBT) piezoelectric ceramics are investigated. The piezoelectric properties of NBT ceramics are significantly enhanced by (KCe) substitution. The Curie temperature Tc, and piezoelectric coefficient d₃₃ for the (KCe)-substituted NBT are found to be 663ºC, and 27pC/N, respectively. Dielectric and annealing spectroscopy resent that the (KCe) co-substituted NBT piezoelectric ceramics possess stable piezoelectric properties.

The performance of organic light-emitting diodes (OLEDs) with thick film is optimized. The alternative vanadium oxide (V₂O₅) and N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) layers are used to enhance holes in the emissive region, and 4,7-dipheny-1,10-phenanthroline (Bphen) doped 8-tris-hydroxyquinoline aluminium (Alq₃) is used to enhance electrons in the emissive region, thus ITO/V₂O₅ (8nm)/NPB (52nm)/V₂O₅ (8nm)/NPB (52nm)/Alq₃ (30 and 45nm)/Alq₃:Bphen (30wt%, 30 and 45nm)/LiF (1nm)/Al (120nm) devices are fabricated. The thick-film devices show the turn-on voltage of about 3V and the maximal power efficiency of 4.5lm/W, which is 1.46 times higher than the conventional thin-film OLEDs.

We fabricate the hybrid films of colloidal CdSe/ZnS quantum dots (QDs) and poly(9-vinylcarbazole) (PVK) sandwiched between two electrodes. The voltage and temperature dependences of the electroluminescence (EL) are measured. The quantum-confined Stark effect of colloidal QDs is clearly observed. To explore the mechanism in the QD EL, hybrid films are fabricated with different concentrations of colloidal QDs. Electrons and holes are proposed to be separately transported in QDs and PVK, respectively.

The influence of dopants in ZnO films on defects is investigated by slow positron annihilation technique. The results show S that parameters meet S_Al>S_un>S_Ag for Al-doped ZnO films, undoped and Ag-doped ZnO films. Zinc vacancies are found in all ZnO films with different dopants. According to S parameter and the same defect type, it can be induced that the zinc vacancy concentration is the highest in the Al-doped ZnO film, and it is the least in the Ag-doped ZnO film. When Al atoms are doped in the ZnO films grown on silicon substrates, Zn vacancies increase as compared to the undoped and Ag-doped ZnO films. The dopant concentration could determine the position of Fermi level in materials, while defect formation energy of zinc vacancy strongly depends on the position of Fermi level, so its concentration varies with dopant element and dopant concentration.

A fully three-dimensional Monte Carlo model for simulation of sculptured thin-film growth is presented. After explaining the model, the simulation results are compared with the corresponding experiments, and encouraging consistency is proven. The morphology of sculptured thin films is then compared on periodical patterned and bare substrates. It is shown that there are more uniform structures and hence possible better optical properties by fabricating on patterned substrates. Finally, with the aid of computer simulation, we examine the self-shadowing effect and our theoretical analysis of simulated morphology data deals with the accuracy of this model.

Femtosecond laser ablation of silver plate placed in water is used to produce nanoparticle suspension. The method is easy to operate and the suspension is relatively stable. The optical properties and the size distribution of the suspension are studied with UV-vis absorption spectroscopy and dynamic light scattering, respectively. The shape of the nanoparticles is investigated by an atomic force microscope, which is near spherical. There are two kinds of nanoparticles, small particles with diameter about 35nm, and large particles with diameter about 120nm.

A series of GaAs_1-ySb_y epilayers are grown on GaAs substrates under different growth conditions. Different antimony compositions of samples with
beryllium doping are obtained. A non-equilibrium thermodynamics model is used to calibrate and fit the Sb composition. Activation energy of 0.37eV for the dissociation process of Sb₄ molecules is obtained. Carrier mobility and concentration of samples are influenced by the Sb composition. Quasi-qualitative analysis of mobility is used to explain the relations among Sb composition, carrier mobility and concentration. High resolution x-ray diffraction (HRXRD) rocking curves and Hall effects measurements are used to determine the crystal quality, carrier mobility and concentration.

Brownian dynamics simulation is conducted for a dilute surfactant solution under a steady uniaxial elongational flow. A new inter-cluster potential is used for the interaction among surfactant micelles to determine the micellar network structures in the surfactant solution. The micellar network is successfully simulated. It is formed at low elongation rates and destroyed by high elongation rates. The computed elongational viscosities show elongation-thinning characteristics.The relationship between the elongational viscosities and the microstructure of the surfactant solution is revealed.

A photonic crystal fibre (PCF) surface enhanced Raman scattering (SERS) sensor is developed based on silver nanoparticle colloid. Analyte solution and silver nanoparticles are injected into the air holes of PCF by a simple modified syringe to overcome mass-transport constraints, allowing more silver nanoparticles involved in SERS activity. This sensor offers significant benefit over the conventional SERS sensor with high flexibility, easy manufacture. We demonstrate the detection of 4-mercaptobenzoic acid (4-MBA) molecules with the injecting way and the common dipping measurement. The injecting way shows obviously better results than the dipping one. Theoretical analysis indicates that this PCF SERS substrate offers enhancement of about 7 orders of magnitude in SERS active area.

ZnS quantum dots (QDs), prepared by soft-condensation, exhibit robust structure of a quantum size equal 3.13 nm mediated two-dimensional gum Arabic surfactant as characterized by scan tunnelling microscope (STM). Strong blue-shifted absorption and emission bands are depicted by optical characterization even for the sample stored under ambient condition for two weeks. These enhancements can be attributed to the completely passivated surface trap states by Gum Arabic.