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On the basis of the density functional theory of the first-principles, we employ the plane wave pseudopotential method and local density approximation to optimize the geometrical structure of cubic boron nitride and hexagonal boron nitride; then we study their mechanical properties, electronic structures and optical properties at zero temperature and zero pressure, and the thermodynamic properties at different temperatures and different pressures. By means of geometry optimization, we systematically investigate the elastic constant, bulk modulus, shear modulus, hardness and phonon spectrum for each of cubic boron nitride and hexagonal boron nitride. The results show that both cubic boron nitride and hexagonal boron nitride are structurally stable and brittle materials. Besides, cubic boron nitride is more stable than hexagonal boron nitride and it can be used as a superhard material. However, the thermal stability of hexagonal boron nitride is poor. The research results of electrical properties show that both cubic boron nitride and hexagonal boron nitride are indirect bandgap semiconductors, and the localization of cubic boron nitride is stronger than hexagonal boron nitride. The optical studies show that both cubic boron nitride and hexagonal boron nitride have good passivity to incident light. The c-BN is more sensitive to the incident light in high energy region. Last but not least, the thermodynamic properties of cubic boron nitride at high temperature and high pressure are also investigated. The relationships of thermodynamic expansivity, heat capacity, Debye temperature and Grüneisen parameter of c-BN with temperature and pressure are obtained. And the heat capacity of cubic boron nitride is found to be close to the Dulong-Petit limit at high temperatures. In this paper the relevant properties of cubic boron nitride and hexagonal boron nitride under high pressure are described theoretically, and a relatively reliable theoretical basis is provided for relevant experimental research.

Nanosecond-pulse discharge can produce low-temperature plasma with high electron energy and power density in atmospheric air, thus it has been widely used in the fields of biomedical science, surface treatment, chemical deposition, flow control, plasma combustion and gas diode. However, some phenomena in nanosecond-pulse discharge cannot be explained by traditional discharge theories (Townsend theory and streamer theory), thus the mechanism of pulsed gas discharge based on runaway breakdown of high-energy electrons has been proposed. Generally, the generation and propagation of runaway electrons are accompanied by the generation of X-ray. Therefore, the properties of X-ray can indirectly reveal the characteristics of high-energy runaway electrons in nanosecond-pulse discharges. In this paper, in order to explore the characteristics of runaway electrons and the mechanism of nanosecond-pulse discharge, the temporal properties of X-ray in nanosecond-pulse discharge are investigated. A nanosecond power supply VPG-30-200 (with peak voltage 0200 kV, rising time 1.2-1.6 ns, and full width at half maximum 3-5 ns) is used to produce nanosecond-pulse discharge. The discharge is generated in a tube-to-plane electrode at atmospheric pressure. Effects of the inter-electrode gap, anode thickness and position on the characteristics of X-ray are investigated by measuring the temporal X-ray via a diamond photoconductive device. The experimental results show that X-ray in nanosecond-pulse discharge has a rising time of 1 ns, a pulse width of about 2 ns and a calculated energy of about 2.310-3 J. The detected X-ray energy decreases with the increase of inter-electrode gap, because the longer discharge gap reduces the electric field and the number of runaway electrons, weakening the bremsstrahlung at the anode. When the inter-electrode gap is 50 mm, the discharge mode is converted from a diffuse into a corona, resulting in a rapid decrease in X-ray energy. Furthermore, both X-ray energies measured behind the anode and on the side of discharge chamber decrease as anode thickness increases. The X-ray energy measured on the side of the discharge chamber is one order of magnitude higher than that measured behind the anode, which is because the anode foil absorbs some X-rays when they cross the foil. In addition, the X-ray energy behind the anode significantly decreases with the increase of the thickness of anode aluminum foil. It indicates that the X-ray in nanosecond-pulse discharge mainly comes from the bremsstrahlung caused by the collision between the high-energy runaway electrons and inner surface of the anode foil. Therefore, increasing the thickness of the anode foil will reduce the X-ray energy across the anode film.

Porous anodic alumina thin films with rainbow rings were fabricated in oxalic acid electrolyte by one-step electrochemical oxidation of Al sheet. The hole depth and aperture diminish symmetrically outward from the center of the films. The relationship between the density of rainbow rings to the oxidation voltage and the time in oxalic acid solution are discussed. Theoretical study on the formation mechanism of porous anodic alumina thin films with rainbow rings indicates that the effect of carbon rod is similar to carbon dot electrode in the process of anode electrochemical reaction. Result of the theoretical study is consistent with the experimental phenomenology.

We modify the deterministic Eigen model of species evolution into a randomized model in order to render the Eigen model more realistic for the description of species evolution. In the framework of the Eigen model, we regard the locus mutation rate of a genetic sequence as a Gaussian distributed random variable. Thus the Eigen model turns into a random model. In this randomized model, we can see that when the fluctuation strength of the mutation rate is small, the error threshold of the quasispecies changes slightly and still serves as a phase transition point. However, when the fluctuation strength becomes large, the error threshold shifts from a phase transition point into a crossover region. Since the error threshold in the real species evolution is a crossover region, we should consider the upper limit of the crossover region when dealing with practical problems.

Fe doped TiO2 films are deposited on glass substrates using dc magnetron sputtering. The crystal structures and the magnetic properties of these films are studied. Room temperature ferromagnetism is observed in each of all the Fe doped TiO2 films. The source of magnetism is related to an exchange interaction between the transition-metal (Fe) ions and localized strapped holes. The maximal magnetization is observed in a TiO2 film with Fe concentration 7%. With the increase of Fe concentration, the crystal structure of TiO2 film transforms gradually from anatase phase to rutile phases, and magnetism in the film weakened. The changes of crystal structure and crystallization in TiO2 film resulting from Fe doping affect the change of ferromagnetism in the film.

The non-magnetic element Al and magnetic element Co doped ZnO films are prepared by dc magnetron sputtering The films were annealed first in vacuum and then in air. The crystal structures are analyzed by x-ray diffraction (XRD) and magnetic properties are measured by Physical Properties Measurement System (PPMS). The results show that annealing ambience has a great influence on structure and magnetic property of sample Al doped ZnO films annealed in vacuum show no room temperature ferromagnetism, but the ones annealed in air show room temperature ferromagnetism. The room temperature ferromagnetism may be associated with enhanced charge transfer between Al and ZnO films annealed in air. And for Co doped ZnO films annealed in air annealed, the ferromagnetism is weakened. The change of magnetism may be related to the competition between enhanced magnetism resulting from charge transfer between Al and ZnO and reduced magnetism resulting from interstitial Co atoms oxygenated.

Arrays of Ni1-xMnxFe2O4 (x = 0.0, 0.25, 0.5, 0.75) nanowires with an average diameter of about 80 nm are prepared by porous anodic aluminum oxide membrane poured sol technique. X-ray diffraction analysis shows that the nickel manganese ferrites nanowires with cubic spinel structure are synthetized. Scanning electron microscopy and transmission electron microscope images indicate that the nanowire arrays are composed of prolate spheroids with different crystal orientations. Magnetic measurements show that saturation magnetization increases and then decreases with Mn increasing. The change is related to the location and the substitution of ion in spinel structure. Compared with of block material NiFe2O4, the saturation magnetization of nickel ferrite nanowire arrays is low. This is due to the fact that the noncollinear magnetic structure in nanowire arrays become predominant.

Combining the observer and adaptive method, chaos synchronization is realized for a class of the perturbed chaotic systems with unknown parameters. Lyapunov stability theory and Barbalat lemma are adopted to design observer for achieving chaos synchronization. This method has fewer constraints and can be applied to many chaotic systems. Numerical simulations of representative chaotic systems further verify the validity of the proposed method.

Dielectrophoresis （DEP） has a high potential in the manipulation of low concentration microparticles in microsystem, which is an urgent project. The complex DEP expression was induced based on the basic DEP theory. The main factor of the conventional DEP force and the traveling wave DEP force was analyzed and 2D analytical model with star electrodes as well as parallel electrodes were founded in order to act as the manipulation construction of them. Boundary conditions were set and the real part and imaginary part were coupled to compute the DEP force. The DEP distribution of the two electrodes was simulated numerically in order to obtain the parameters for the experiment. Based on the conventional DEP force, the star electrodes were used to collect microparticles and based on the travelling wave DEP force, the parallel electrodes were used for microparticles lift and directional driving, respectively. Comparing the experimental results with theoretical and simulation analysis, they had a good agreement. The results show that DEP force can be used to manipulate microparticles effectively in microsystem.

Using the reactive radio-frequent magnetron sputtering method, ZnO thin films were deposited on pretreated (100) sapphire substrates. The effect of substrate pretreatments on the growth of ZnO films was studied with the structural and morphological characterization using atomic force microscopy, reflection high-energy electron diffraction and X-ray diffraction. It was found that both the original substrate and the substrates annealed in vacuum (8×10-4 Pa), nitrogen atmosphere (40 Pa), and oxygen atmosphere (40 Pa) at 750℃ for 4h have the same surface structure that can be indexed to be α-Al2O3 (001). The surface morphologies of the substrates are different from each other. All the ZnO films grown on the substrates are highly c-axis textured. Their morphologies, however, are related to the pretreatment. For the substrate annealed in vacuum, the film has the morphology with -c and +c epitaxial islands, similar to ZnO grown on the untreated substrate. For the substrate annealed in nitrogen, the film has the morphology with only -c epitaxial islands and has quite large grains and surface roughness. For the substrate annealed in oxygen, the films also has the morphology with -c epitaxial islands, but the surface is much smoother. The surface roughness is as small as 15nm.

Using reactive radio-frequency magnetron sputtering, ZnO films have been deposited on Si(001) substrate with a two-step growth method. The first step: depositing a ZnO buffer layer at low temperature and annealing at 800 ℃, the second step: growing the ZnO at the temperature of 750 ℃. In this paper, we discuss the dependence of the ZnO film growth on the etching time of Si chips and the deposition time of the buffer layer. It is found that different deposition time of the buffer layer results in the difference in the morphology of ZnO films. The difference can be related to the coverage of the buffer layer. When the buffer layer does not cover the substrate, the ZnO film has small grains similar to the film without buffer layer and quite large roughness and internal stress. When the substrate is completely covered by the buffer layer, a ZnO film can be obtained with large-sized grains, smooth surface and low internal stress. The growth behavior of the ZnO films is also related to the etching time of Si chip. With the increase of etching time, both the roughness of the ZnO films and the correlation length of the self-affine morphology decrease.

ZnO thin films were electrodeposited on glasses coated with a transparent-conductive film (InSnO) with different deposition currents. We have studied the dependence of microstructure, morphology and photoluminescence (PL) on the deposition current by X-ray diffraction, scanning electron microscopy and PL measurement at room temperature. We found that all the films show highly c-axis textured structure and the surface morphology is strongly current-dependent. The transmission spectra show that the films have a transmittance higher than 80% in the visible range. The films have an increase in thickness with the deposition current. The PL spectra exhibit two emission bands, an ultraviolet (UV) one from the exciton transition and a visible light one that might emerge from the defects in the films. The UV emission band has an obvious blueshift, which is found to be due to in doping during the deposition. With the increase of deposition current, the UV emission decreases while the visible light emission goes up.

Atomic force microscopy has been applied to study the morphological evolution o f ZnO film on Si(100) and Si(111) substrates with a native oxide layer. With dyn amic scaling of the film morphology at different growth stages, the nucleation a nd growth behavior have been studied for ZnO films deposited by radio-frequency reactive magnetron sputtering. It is found that ZnO film has three nucleation st ages, namely the stages of initial nucleation, low-rate nucleation, and seconda ry nucleation. The growth exponents of the three stages are β1=1.04 ，β2=0.25±0.01 and β3=0.74 for ZnO film on Si(100) and β1=0.51，β2=0.08±0.02 and β3=0.63 for ZnO f ilm on Si(111), respectively. In the initial nucleation stage, the intrinsic def ects on Si substrates may be responsible for the surface roughening and the dens ity of surface defects determines the nucleation density of ZnO films. The growt h behavior of ZnO film is dominated by the diffusion effect and oriented growth mechanism, as well as the coarsening mechanism induced by the lattice mismatch s tress. In the low-rate nucleation stage, few new ZnO islands are detected and t he films are roughened slowly in morphology. The deposition rate plays a role of controlling the morphological evolution and the lattice mismatch stress may be released in this stage. The secondary nucleation of ZnO films may result from th e bombardment of energetic ions or atoms on the surface of Si substrates. In the secondary nucleation stage, shadowing effect may influence the roughening of Z nO films. In the stage of steady growth, ZnO films have a roughness value much l ower than the ones in nucleation stages and grow in the form of columnar grains.

A compensated compact microstrip resonant cell (C-CMRC) with photonic band-gap (PBG) performance is presented in this paper. Two open microstrip stub-lines are added at the center of the compact microstrip resonant cell (CMRC) to compensate for the unbalanced change of inductance and capacitance in low pass band. It can significantly improve the return loss and insertion loss. Furthermore, the C-CMRC with capacitive loading leads to a stronger slow-wave and enlarged stop-band bandwidth. A low pass filter with 3 C-CMRC resonators in series has been designed according to the PBG performance. The period is only 0.15λg due to the slow-wave effect. Comparison with the general PBG period of 0.5λg, the circuit size is reduced effectively. The original CMRC and the C-CMRC with open stub lines are designed, fabricated and measured to validate the improved performance. A low pass filter with 3 C-CMRC resonators is also designed with 1.26dB insertion loss below 1.8GHz and more than 25dB stop-band from 2.6 to 9GHz.

Using the reactive radio-frequency magnetron sputtering method, ZnO films were deposited on Si (001) and quartz substrates at different pressures with a fixed flow ratio of Ar to O2. The influence of working pressure on the crystallinity and growth behavior were studied with the help of characterization of the morphology, microstructure and optical properties of the films by atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and transmittance spectra,respectively. It is found that a critical working pressure can be taken as 0.5—1.0 Pa. With increasing the working pressure from 0.1 Pa up to the critical working pressure, the density of ZnO grains decreases and the films have high c-axis orientation with strong in-plane textured feature. When the working pressure exceeds the critical working pressure, the density of ZnO grains is roughtly a constant and the in-plane textured feature disappears. The influence of working pressure on the refractive index, extinction coefficient and optical energy gap is also discussed in the paper.

Bis (trimethylsiloxy) silicon naphthalocyanine (SiNc) LB films were fabricated to align nematic liquid crystals. Films obtained under different surface pressures exhibit different alignment effects. Films obtained under surface pressure of 15mN/m will induce a planar alignment, while those obtained under 30mN/m will induce a homeotropic alignment. Atomic force microscopy reveals that on films prepared under high surface pressure the SiNc molecules stack into separate monomers or aggregates to form lines of nanometer size with molecular macrocycles perpendicular to the surface of the film and the dipping direction of its formation. In addition, there are grooves of molecular size between the stacked SiNc molecular lines. Similar formation occurs in films prepared under low surface pressures, only instead of molecules all lying perpendicular to the surface, many SiNc molecules are lying obliquely to the film surface or even lying on the surface. The mechanism of the liquid crystal alignment is also discussed.

The temperature fluctuation of the stainless steel irradiated by a CW CO2 laser is studied. In the experiment, the temperature fluctuation and the temperature rise is measured by the infrared thermal imagers. It is found that the maximum amplitude of the temperature fluctuation is kept constant with the increase of the laser heating time; this is different from aluminum, low carbon steel, epoxylite and polymethylmethacrylate. This characteristic of the stainless steel is determined by the variance of thermal conductivity and thermal diffusivity with the increase of temperature. A thorough study of the effects of the material thermal properties on the temperature fluctuation is needed.

The single electron capture cross sections for 5-30keV Ho+, La+ and Ce+ impact on H2 at a fixed anode voltage of an ion source and 10keV Ho+ impact on H2 at different anode voltage have been measured by the “growth rate method”. We found that the variation of the hollow cathode ion source’s anode voltage affected the proportion of the metastable states of the rare earth ions, and the proportion accounts for the significant change of single capture cross sections.