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We give an analysis of the frequency distribution trends in the four lowest bands of two-dimensional square lattices formed by holographic lithography (HL) and in the lattices of the same kind but with regular dielectric columns with increasing filling ratios, and then present a comparative study on the left-handed properties in these two kinds of structures using plane wave expansion method and finite-difference time-domain (FDTD) simulations. The results show that the left-handed properties are more likely to exist in structures with large high-epsilon filling ratios or in a connected lattice.

A new ternary photopolymer system is used in fabricating photonic crystals (PhCs) with controlled defects by combination of single-photon and two-photon photopolymerization. The former process can produce PhCs in one-step recording with a low-power (tens mW) continuous-wave laser at 532 nm, while the latter can create desired defects. The preparation of the material, the optical setup and the preliminary experimental results are given. Compared with other methods, this approach is much more accessible and convenient for use of visible light and has advantages of making PhCs in a large scale quickly and economically and introducing any defects exactly, especially for three-dimensional structures.

By using a plane wave expansion method, some important parameters of designing the hollow-core fibre with cobweb cladding structure are analysed. Taking a dielectric material PMMA, for example, the tolerance of the parameters is discussed. The results show that the parameters of the structure possess oneself of a regularity and limit, and have a larger tolerance for the structural parameters in fabrication.

CuInSe2 (CIS) nanoparticle thin films have been prepared by radio frequency reactive magnetron sputtering from compound ternary fan-shaped targets on low-temperature substrates with pure argon gas as the atmosphere. The stoichiometry of the ternary compound semiconductor quantum dots can easily be controlled by the ratios of the ternary elements and sputtering parameters. CIS nanoparticle thin films regularly shaped and distributed reasonably uniform in size on substrates of 7059 glass etc can be grown in this way. The average particle diameter can be varied between 40-80 nm by an appropriate choice of the substrate temperature, power density and total CIS coverage. The optical and electrical properties of the CIS films have also been studied.

The direct ionization cross sections for electron scattering by nitrogen are calculated by applying an equivalent-local optical model from 15 eV to 1100 eV. The present results are compared with the experimental data and other theoretical calculation results.

A novel characteristic of the junction current drift effect in the Cu/porous silicon (Cu/PS) device prepared by electrodeposition in which Cu ions were deposited on porous silicon is reported. The junction current increases with time and gradually approaches to a saturated value when a certain forward bias is applied on the Cu/PS device. Moreover, after the bias was withdrawn for a period, a different drift process was observed when the same bias was applied again. The drift-time constant and the initial current of latter drift process depend on cut-off time. Sucn an effect is explained in terms of the model that only part of electrons from porous silicon contributes to the junction current while other electrons are captured by the traps in the interface between Cu and porous silicon in the Cu/PS device.

The charge transfer rate coefficients for reactions of SC3+ with N-2 and H-2 have been measured at the mean collision energy of 4.2 eV. The rate coefficients are derived from the decay rate of ion signals by using ion storage in a radio frequency ion trap. The rate coefficients are 8.18(0.18) x 10(-10)cm(3.)s(-1) at T-equiv x 1.26 x 10(4) K for SC3+ with N-2 and 1.44(0.39) x 10(-9)cm(3.)s(-1) at T-equiv approximate to 1.67 x 10(3) K for Sc3+ with H-2, respectively. Both results are comparable with the Langevin rate coefficients.

We present the novel results of excitation intensity dependent photoluminescence (PL) in a-C:H and a-C thin films. Sublinear and superlinear phenomena of PL have been observed for a-C:H films. There are two PL bands in a-C films under lower excitation intensity. These results are qualitatively explained in the light of band tail state saturation and the contribution of gap states.

An external weak electric field is introduced into the small-world networks of Hodgkin-Huxley neurons to study the control and breakup of a spiral wave. The effect of an external electric field on the neurons in the small-world network is described by an additive perturbation on the membrane potentials of neurons at the cellular level, in which an additive term VE is imposed on the physiological membrane potential. A statistical factor of synchronization is used to measure the collective behaviour of spiral waves by changing the electric field; it is confirmed that a smaller factor of synchronization is associated with the survival of a spiral wave. In the case of no channel noise, the spiral wave could be removed under a certain intensity of constant electric field; it keeps robustly to the weak electric field when the electric field changes periodically. In the case of weak channel noise, a breakup of the spiral wave is observed when the intensity of the electric field exceeds certain thresholds, which could be measured from the curve for synchronization factors. No drift of the spiral wave is observed under the weak electric field.

We provide alternatively a simple way of computing the Fresnel field integral, a further extension to the Gaussian-beam expansion. With a known result that the circ function is approximately decomposed into a sum of Gaussian functions, the zero-order Bessel function of the first kind is similarly expanded by the Bessel—Fourior transform. Two expansions are together inserted in this integral, which is then expressible in terms of the simple algebraic functions. The approach is useful in treatment of the field radiation problem for a large and important group of piston sources in acoustics. As examples, the calculation results for the uniform and the simply supported piston sources are presented, in a good agreement with those evaluated by numerical integration.

The vibrational resonance and stochastic resonance phenomena in the FitzHugh—Nagumo (FHN) neural model, driven by a high-frequency (HF) signal and a low-frequency (LF) signal and by coupled multiplicative and additive noises, is investigated. For the case that the frequency of the HF signal is much higher than that of the LF signal, under the adiabatic approximation condition, the expression of the signal-to-noise ratio (SNR) with respect to the LF signal is obtained. It is shown that the SNR is a non-monotonous function of the amplitude and frequency of the HF signal. In addition, the SNR varies non-monotonically with the increasing intensities of the multiplicative and additive noise as well as with the increasing system parameters of the FHN model. The influence of the coupling strength between the multiplicative and additive noises on the SNR is discussed.

A prototype ZnO:Al/amorphous-FeSi2 heterojunction was successfully prepared on a glass substrate by magnetron sputtering at room temperature. The structural and electrical properties of as-deposited FeSi2 thin films were investigated using x-ray diffraction, Raman scattering, resistivity, and carrier lifetime measurement. The FeSi2 thin film showed an amorphous phase with resistivity of 9.685 ??cm and carrier lifetime of 9.5 ?s. The prototype ZnO:Al/amorphous-FeSi2 heterojunction exhibited a rectifying property of the diode from the dark current-voltage characteristic. This propert was evaluated using the shunt resistance and diode ideal factor. The experimental results suggest that the amorphous-FeSi2 thin film has promising applications in heterojunction devices with low thermal budget and low product cost.

Helium-containing titanium films were prepared on Si substrates with various biases applied by magnetron sputtering under stable He/Ar ambiance. Rutherford backscattering and elastic recoil detection analyses are used to measure the thickness of the He-Ti films and the helium depth profile, respectively. Experiments of x-ray diffraction and variable energy positron annihilation spectroscopy are carried out to investigate the microstructures of titanium films and the corresponding helium-related defects developed. The behavior of the implanted He, the microstructure of the He-Ti film and the formation of He-related defects all are affected by the substrate biases applied.

Stochastic resonance in a time-delayed bistable system subject to asymmetric dichotomous noise and multiplicative and additive white noise is investigated. Using small time delay approximation, we obtain the expression of the signal-to-noise ratio (SNR). It is found that the SNR is a non-monotonic function of the delayed times, of the amplitude of the input square-wave signal, as well as of the asymmetry of the dichotomous noise. In addition, the SNR varies non-monotonously with the system parameters, with the intensities of the multiplicative and additive noise, as well as with the correlate rate of the dichotomous noise.

Effect of delayed time in the logistic growth model subject to weak periodic signal and correlated multiplicative and additive white noise is investigated. Using small time delay approximation, we obtain the expression of the signal-to-noise ratio (SNR). It is found that the SNR is non-monotonic functions of the delayed times, the system parameters, the intensities of the multiplicative and additive noise, as well as the correlation strength of the two noises.

A nonlinear flow mathematical model is established and the grid equation is deduced. A nonlinear flow reservoir numerical simulation program is compiled. The permeability loss coefficient is used to describe the permeability loss. A pilot calculation is made on the basis of actual field data, which reflects the reservoir development characteristics. The numerical simulation program based on nonlinear flow can anticipate the dynamic characteristics of the ultra-low permeability reservoir exploitation more exactly.

A torsion balance is constructed to accurately measure the magnetic properties of the real proof mass of the inertial sensor. The magnetic susceptibility and remnant moment of a titanium proof mass are measured in the first experiment, and further improvements and the potential sensitivity are also discussed. This is significant for choosing the material of the proof mass and investigating the magnetic disturbances acting on the proof mass.

The low energy scattering of electrons by sodium at incident energies up to ionization threshold are calculated by applying the momentum space coupled-channel-optical (CCO) method. The present results are in good agreement with the previous experimental and theoretical results. Furthermore, three resonances in the total cross sections observed by previous experiments are proved by the present calculation.