The research status of two active laser crystal fields, Yb doped crystals and Raman crystals, are reviewed. Yb-doped crystals can produce high power laser output, and they are very important research fields. And fs (femtosecon) laser outputs from Yb-doped crystals can be obtained pumped by laser diode. Many wavelength laser can be produced by using Raman crystal, so Raman crystal may have many potential applications. The advantages, possible applications and new developments are also expatiated in this paper.

High-power photoconductive semiconductor switches (PCSS) were fabricated on 0.2at％ vanadium-doped semi-insulating 6H-SiC (7.0×10⁸Ω·cm). V-doped 6H-SiC PCSS with 1mm gap displays a fast rise time (6.8ns), short photoconductivity pulse width (less than 20ns) and high-speed hotovoltaic response to 20ns laser pulse. The experimental results show that the linear peak voltage is increased with increasing bias voltage and excitation energy. The typical maximum photocurrent of the device at 2.5kV is about 57.5A, the peak electrical power delivered to a 40Ω load is 132kW.

Neodymium-doped yttrium aluminum garnet (Nd:YAG) transparent ceramic with doping concentration of 1.0at％ was fabricated by a solid state reaction method and vacuum sintering. The absorption spectrum and the fluorescence spectrum of the sample were measured. The highest absorption peak is centered at 808nm and the absorption cross section is 3.1×10^-20cm². The main emission peak is at 1064nm, and the fluorescence lifetime is 257μs. The Judd-Ofelt intensity parameter Ωλ(λ=2, 4, 6), spontaneous transition probability, fluorescence branching ratio and radiative lifetime of Nd3+ were calculated by Judd-Ofelt theory. Finally, the stimulated emission cross section of ⁴F_3/2→⁴I_11/2 transition calculated is 3.81×10^-19cm². It is found that the prepared Nd:YAG transparent ceramic has large stimulated emission cross section and high fluorescence quantum efficiency, which is a potentially excellent laser material.

Lu_xY_1-xAlO₃:Ce single crystal samples were prepared by the Czochralski method. Based on X-ray diffraction (XRD) and composition analyses, and analysis of phase diagram of Lu₂O ₃-Al₂O₃ and the structural stability of Lu_xY_1-xAlO₃:Ce, it is supposed that as the content of Lu increase, the melt delamination is exacerbated, and the crystallization interval of Lu_{x 1-x}AlO₃:Ce in the phase diagram may shift towards the interval rich in Lu, resulting in the accompaniment of (Lu,Y)₃Al₅O₁₂:Ce on the top of Lu_xY_1-xAlO₃ :Ce single crystals. With the increase of the content of Lu, the thermal stability of Lu_xY_1-xAlO₃:Ce single crystals decreases, the oxygen vacancy in those crystals furthers the decrease, so the seed surface tends to decompose into (Lu,Y₃ Al₅O₁₂:Ce and (Lu,Y)₄Al₂O₉:Ce while seeding, and the former decomposition product provides the crystal nucleus to induce crystallization of (Lu,Y₃Al ₅O₁₂:Ce, resulting in the accompaniment of (Lu,Y)₃Al₅O₁₂:Ce on the coat of Lu_xY_1-xAlO₃:Ce single crystals. An adjustment of the melt composition to make the mol ratio n((Lu,Y)₂O₃):n(Al₂O₃) equal to 1.17--1.00, and a greater temperature gradient inside the melt and at the solid liquid interface to improve melt convection, restrain melt delamination and the decomposition on the seed surface may contribute to the acquisition of Lu_x Y_1-xAlO₃:Ce with high Lu content.

Sapphire single crystal was grown by micro-pulling and shoulder at cooled center (SAPMAC) technique and the air bubbles were observed as one of the main defects in the as-grown crystals. Based on the growth parameters, the formation mechanism of the bubbles was discussed in the view of the crystal growth kinetics. It suggests that optimizing the temperature distribution in the furnace, selecting a suitable growth velocity and adopting a slightly convex interface to the melt can effectively reduce the quantity of bubbles.

SrTiO₃ photocatalysts were prepared by a sol-gel method, and nitrogen-doped SrTiO₃ were further prepared by a solid phase method. Nitrogen-doped SrTiO₃ loaded with Pt were prepared by photodeposition method and hydrogen reduction method. These photocatalysts were characterized by XRD, SEM, UV-Vis diffuse reflectance spectra, fluorescence spectrum and the photocatalytic hydrogen generation activities were investigated under visible light irradiation. The effects of different nitrogen sources, doped content, calcination temperature and the content of loaded Pt on the hydrogen generation activity of catalysts were investigated. The results indicate that three nitrogen source reagents demonstrate different doping effect, i.e. hexamethylenetetramine(HMT)>EDTA>urea and the doping effect of EDTA is slightly lower than HMT. On the condition that the nitrogen source is HMT, the mass proportion of SrTiO₃ and HMT is 1:3, and the calcination temperature is 450℃, the optimized photocatalytic hydrogen generation activity of photocatalysts can be achieved. The photocatalytic hydrogen generation activity is greatly improved by loading metal Pt. The photocatalytic activity of photocatalysts prepared by hydrogen reduction method is better than that prepared by photodeposition method. On the condition that the optimized loaded content is 2wt％, the hydrogen generation amounts of these two photocatalysts are up to 6.89mmol and 2.24mmol within 6h respectively, which are 12 times and 4 times more than that of the unloaded Pt samples.

Novel Pt/BiVO₄ photocatalysts were prepared by impregnation method using Bi(NO₃)₃, NH₄VO₃ and H₂ PtCl₆ as starting materials. The obtained samples were characterized by XRD, SEM, XPS and DRS. The XRD patterns indicate that the Pt/BiVO₄ photocatalysts consist of monoclinic phase. The DRS measurements show that the visible light absorption of the composite samples is greatly increased, and the absorption edge shifts to red light region. The photocatalytic activities were evaluated by degradation of methyl orange under visible light irradiation (λ>400nm). The photocatalytic activity of the Pt/BiVO₄ composite sample is significautly enhanced, which is probably due to the photo-sensitivity of PtCl₄ particles.

CuO/γ-Al₂O₃ samples were prepared by impregnating γ-Al₂O₃ with an aqueous solution containing requisite amount of Cu(NO₃)₂. BET, XRD, UV-DRS, H₂-TPR and CO oxidation were employed to characterize the dispersion, reduction behavior and catalytic properties of CuO/γ-Al₂O₃ catalyst calcinated at different temperatures. The results indicate that the dispersion capacity of CuO on the surface of γ-Al₂O₃ is about 0.56mmol/100m² when it is calcinated at 450℃; while for the samples calcinated at 750℃, Cu²⁺ would occupy both the octahedral and tetrahedral vacant sites on the (110) plane of γ-Al₂O₃. For samples with low CuO loading amount, only the reduction peak of Cu²⁺ in octahedral coordination environment is observed in xxCu/Al-450 samples; while for xx Cu/Al-750 samples, the reduction peaks of Cu²⁺ in octahedral and tetrahedral coordination environment can be observed and the reduction of Cu²⁺ in octahedral coordination environment would promote the reduction of Cu²⁺ in tetrahedral coordination environment. The CO oxidation results indicate that the activity of dispersed CuO species in octahedral coordination environment is higher than that in tetrahedral coordination environment.

The α-FeOOH nanorods were prepared via hydrothermal reaction of Fe(NO₃)₃·9H₂O and KOH at
100℃ for 6h. Then the α-FeOOH nanords were heat treated at different temperautres, and single crystalline and multiporous α-Fe₂O₃ nanorods were obtained. The phase and morphology of the samples were characterized by XRD and TEM. The heat treatment process was investigated by TGA and FT-IR. The results show that the phase transition of α-FeOOH→α-Fe₂O₃ occurrs between 239℃ and 259.1℃. The α-Fe₂O₃ still keeps in rod shape and lots of holes appear on the surface which disappear with the temperature increasing. The catalytic performance of α-Fe₂O₃ nanorods was studied by decomposition of ammonium perchlorate(AP) based on DTA. The higher-temperature of exothermic peak of AP shifts towards low temperature when α-Fe₂O₃ nanorods are introduced into the reaction, and the largest decrement reaches 71.4℃ for the α-Fe₂O₃ nanorods heat treated at 350℃.

An efficient visible-light response composite photocatalyst TiO_2-xN_y/AC was prepared by calcination of the mixture of TiO₂ precursor made by acid catalyzed hydrolysis method and actived carbon (AC) in NH₃ /N₂ atmosphere. Photocatalytic activity was investigated through the photocatalytic degradation of phenol. The separability of TON/AC was determined by gravity
sedimentation. X-ray photoelectron spectroscope, X-ray diffraction, diffuse reflectance spectroscope, Fourier transform infrared spectroscope, scanning electron microscope and N₂ adsorption isotherm were used for catalyst characterization. The results show that anion N is incorporated into TiO₂ lattice and substitutes part of O. TON/AC with suitable N-doping
exhibits high activity under ultraviolet light, visible light and solar light irradiation. Also, TON/AC exhibits better decantability and less deactivation. Doped-N can form a new band gap above the valence band of TiO₂ which can extend the adsorption edge to 450--550nm. In addition, Actived carbon support is beneficial to the high dispersion and large surface area of N-doped TiO₂.

The trivalent samarium doped Sr₂CeO₄ color-tunable phosphors were successfully synthesized by solid state reaction at 1200℃ for 6h and their luminescent characteristics were studied. The results indicate that the host can transfer its exciting energy to rare earth ion Sm³⁺ when excited with 365nm light. The emission color can be changed by tuning activator’s concentration in Sr₂CeO₄:Sm³⁺ phosphors. The doped compound emits strong white light when the concentration of the doped Sm³⁺ is lower than 3％. When the Sm³⁺ concentration is increased from 3％ to 15％, it emits red light. The chromaticity coordinate of Sr₂CeO₄: 1% Sm³⁺ phosphor is measured
to be (x, y) (0.334, 0.320), which is closed to the pure white (0.33, 0.33). It shows that Sr₂CeO₄: 1% Sm³⁺ phosphor is a promising single white phosphor for ultraviolet light-emitting diode.

Magnetic ZSM-5/Ni hollow fibers were synthesized by first growing ZSM-5 layers on Ni/PVDF hollow fibers, which were prepared by electroless plating on poly(vinylidene fluoride) (PVDF) hollow fiber microfiltration membranes, followed by calcination in air at 550℃ for 4h. The samples were characterized by SEM, EDX, XRD, BET, vibrating sample magnetometer (VSM) and TG. The effects of hydrothermal synthesis cycles and temperature on the coating of ZSM-5 crystals on the surfaces of the Ni/PVDF hollow fibers were examined. The results indicate that the thickness of the nickel layer can be regulated by controlling the plating time. A continuous ZSM-5 film can be obtained by hydrothermal treatment twice at 150℃ for 24h. The thickness of the zeolite film can be regulated by controlling the reaction temperature. The saturation magnetization values of the magnetic ZSM-5/Ni hollow fibers prepared after hydrothermal treatment twice at 150℃ for 24h are 9.3A·m²/kg and 20.3A·m²/kg before and after calcination, respectively. The BET specific surface area of the calcined sample is 108m²/g.

In order to get lightweight radar wave absorbers, hollow carbon fibers were prepared from polyacrylonitrile (PAN) hollow fibers by thermo-oxidative stabilization in air and carbonization in nitrogen. The microstructure and microwave absorbing properties of the resultant PAN-based hollow carbon fibers (PAN-HCFs) were studied by SEM, XRD and voter network analyzer. The reflectivity was simulated by using RAMCAD software. Results show that the electromagnetic parameters of the absorbing materials increase with increase of the PAN-HCFs volume fraction. The reflection coefficient apex moves to lower frequencies with the thickness of absorbing material increasing. With increase of volume fraction of the PAN-HCFs, the reflection coefficients increase greatly and the optimal thickness decreases at the same time. It is found that the 2mm thick composites containing 33.30% PAN-HCFs has an absorbing bandwidth of 5.17GHz below -5dB and 2.88GHz below -10dB in the frequency range of 2-18GHz.The lowest reflection is -21.36dB at 10GHz. The PAN-HCFs are proved to be a light conductive radar absorbing materials in view of its hollow structures and microwave absorption properties.

Carbon/carbon (C/C) composites, with a mesophase pitch transition layer between carbon fiber and pyrocarbon, were prepared by two step technique of liquid impregnation-carbonization and chemical vapor infiltration (CVI). The microstructure and mechanical properties of the as-obtained composites were studied by polarized light microscope (PLM), scanning electron microscope (SEM), conventional and high resolution transmission electron microscope (TEM, HRTEM) and mechanical properties tests, respectively. Results show that the mesophase pitch carbon exhibits lamellar structure, while the pyrocarbon exhibits like-crinkle lamellar structure under SEM and the granular structure under TEM. Under HRTEM, the degree of alignment of lattice fringes decreases gradually for mesophase pitch carbon, pyrocarbon and carbon fiber. The non-brittle fracture behavior of the composites is related to multiple crack deflections caused by the multi-interface and micro-cracks within the matrix carbon layer. The flexural strength and the fracture toughness (K_IC) of C/C composites are 244MPa and 9.7MPa·m^1/2, respectively.

Carbon nanotubes were modified by NH₃·H₂O and EDTA, respectively. Then, ZnS nanoparticles were densely and
uniformly coated on modified surfaces of carbon nanotubes through reaction of thioacetamide and zinc acetate in water solution. The samples were characterized by XRD, TEM, SAED, SEM, FTIR and PL spectroscope. Experimental results indicate
that EDTA treatment of the carbon nanotubes is a key factor for the formation of carbon nanotubes/ZnS composite. The PL spectra show that the photoluminescence peaks of the carbon nanotubes/ZnS composite have a small blue shift in comparison with the as-prepared ZnS. A possible formation mechanism is proposed for the carbon nanotubes/ZnS composite．

AlN (Aluminum nitride)-BN (Boron nitride) ceramic composites were prepared by hot-pressing in nitrogen atmosphere at 1850℃. Different contents of CaF₂ and Y₂O₃ were added as sintering additives. The effects of sintering additives and soaking time on crystalline phase, microstructure, and thermal conductivity of AlN-BN composite were explored. The experimental results show that the AlN-BN composites with combined sintering additives CaF₂-Y₂O₃ are pure AlN and BN phases, and the grain boundaries evaporate at high sintering temperature. The dielectric properties of the AlN-BN composites with combined sintering additives Y₂O₃-CaF₂ decrease little, comparing with that of the AlN-BN composites with CaF₂ additive. The thermal conductivity is increased with Y₂O₃ contents increasing in the combined sintering additives of Y₂O₃-CaF₂. When AlN-BN ceramic composites with 3wt%Y₂O₃-3wt%CaF₂ is sintered at 1850℃ for 3h, its thermal conductivity of reaches 132.7W·m^-1·K^-1.

An all-ceramic hinge based on the two dimensional carbon fiber reinforced silicon carbide matrix (C/SiC) composites was prepared by chemical vapor infiltration. The high temperature combustion wind tunnel realized simulation of the transmitting and friction behavior of the hinge at 1800℃ in an oxidizing atmosphere. Based on the coupling stress equivalent simulation system, a characterization method with the change of torque was proposed to evaluate the friction behavior. The friction and wear behavior as well as wear mechanism were studied both at high temperatures in combustion environment and at room temperature in air. The results indicate that the friction torque is stable and insensitive to the sliding time at high
temperatures, which demonstrates stable and reliable friction property and thermal load-carrying ability of the hinge. The
tribochemical reaction products on contact surface may moderate the stress distribution by providing a reaction layer for wear protection and lubrication.

Based on experimental analysis of 2.5D-C/SiC composite, mechanical behavior and damage evolution process under tensile loading were investigated. Tensile damage evolution models in terms of stress and strain for 2.5D-C/SiC composite were presented to disclosure tensile damage evolution law. Experiment shows that the tensile damage process of 2.5D-C/SiC composite along longitudinal and transverse direction is similar, and that tensile stress-strain curve is nonlinear and approximately consists of 3 fold lines corresponding to three specific tangential moduli. The damage process includes three stages: the first is initial damage stage in which the initial micro-cracks of composite cracking; the second is accelerating stage that new micro-cracks appears and opens; the last is decelerating stage that the deflection of micro-cracks and debonding of fiber/matrix interface are major damage mechanisms.

The carbon nanotubes (CNTs) film was prepared on Si substrate by electrophoretic deposition (EPD) and treated by Ar microwave plasma. The microstructure and field emission properties of the as-prepared CNTs films before and after treatment were investigated. High-resolution transmission electron microscope (HRTEM) and Raman spectroscope reveal the microstructural changes of CNTs after the plasma treatment as evidence of the appearance of a large amount of structural defects, the sticking with nanometer size and “needle-like” tips. The field emission measurements indicate that the turn on electric field is increased slightly after treatment. The sample treated by Ar plasma for 10min shows the best field emission J-E property. Compared to that of untreated sample, the threshold field of the CNTs film treated for 10min decreases from 3.12V/μm to 2.54V/μm. And after plasma treatment, the emission current density at applied electric field of 3.3V/μm increase from 18.4mA/cm² to 60.7mA/cm². The mechanism of variation of field emission properties after plasma treatment is discussed.

Carbon grains for binderless molding were prepared by oxidization treatment of mesophase pitch at different temperatures, and carbon materials were prepared. The effects of oxidation temperature, molding pressure, and heat-treatment temperature on the physical properties of the carbon materials were investigated. Results indicate that increase in molding pressure significantly increases mechanical strength of the resulting carbon materials. The resultant carbon materials with homogeneous fine-mosaic texture, high density and strength are obtained when the grains are oxidized at 200℃. The high-performance carbon materials are obtained when the grains oxidized at 200℃, molded at 150MPa and then graphitized at 2200℃, whose density, porosity, bending strength, and compressive strength are 2.02g/cm³, 2.03%, 70.3MPa, 123.3MPa, respectively. Results show that oxidized mesophase pitch is a good precursor for preparing high-performance carbon materials.

Polyborosilazane (PBSZ), a precursor to SiBNC ceramic, was synthesized via cocondensation approach using methyldichlorosilane (MeHSiCl₂), boron trichloride (BCl₃) and hexamethydisilazane (HMDZ) as starting materials. SiBNC ceramics were obtained by pyrolysing the as-synthesized PBSZ in N₂ or NH₃/N₂ atmospheres. The chemical composition, structure and high temperature properties of the polymer and ceramics were investigated byusing EA, XPS, FTIR, NMR, and XRD. The results indicate that the backbone of PBSZ is -Si-N-B- linkage in the form of borazine and C is in the form of Si-CH₃. The ceramic yield of the PBSZ pyrolysed at 1000℃ in N₂ and NH₃/N₂ atmospheres is 63wt% and 61wt%, respectively. The products show excellent high temperature stability which are fully amorphous to 1700℃. Furthermore, only partial crystallization, giving a mixture of Si₃N₄, BN and SiC phases, is observed heating at 1850℃. The weight loss of SiBNC ceramics pyrolyzed in NH₃/N₂ and N₂ atmospheres from 1500℃　to 1850℃ is about 10.0wt% and 3.8wt%, respectively. The N₂ pyrolyzed products show better stability than the NH₃/N₂ pyrolyzed products and have less tendency to crystalline at higher temperature.

Undoped and In-doped SrTiO₃(STO) films were grown on MgO/TiN/Si(100) substrates by pulsed laser deposition(PLD). The growth mechanism, crystallinity, surface morphology, and UV-Raman spectra of the films were studied. Results indicate that undoped STO films show high quality crystalline structure with highly (200) orientation. With Indium doping, the crystallinity of the STO film deteriorate, the first order Raman peaks increase indicating the breaking of crystal symmetry, and the film growth mode change from the layer-by-layer mode to island-layer mixed one, resulting in the roughening of the film surface. Furthermore, the crystallinity and (200) orientation of In-doped STO film can be enhanced significantly by introducing an undoped STO buffer layer.

CuSCN thin film was deposited on glass substrate from solutions at room temperature (20--25℃) by the successive ionic layer adsorption and reaction (SILAR) method. The crystalline structure, morphology, and optical properties of obtained film were characterized by X-ray diffraction, scanning electron microscope, and optical transmittance. The key parameters influencing the deposition of CuSCN on substrate were discussed briefly. The CuSCN film exhibits obvious crystallinity, preferential orientation along c-axis, and dense and uniform morphology. Two classes of CuSCN particles are observed, the larger particles in size of 50--100nm and the smaller ones in size of 20--30nm. The transmittance of the film at the band of 400--800nm is 50%--70%, and the optical band gap is estimated to be 3.94eV. Mechanism analysis indicates that the growth of CuSCN film is affected significantly by three factors, namely, the molar ratio of S2O32- to Cu2+ in the copper precursor, the substrate rinsing mode, and the growth temperature. The relatively high concentration of complex ions, the substrate-rinsing after multiple reaction cycles, and the room-temperature deposition are beneficial to the growth of high quality CuSCN film.

Nanocrystalline (nc) SiC thin films were deposited by helicon wave plasma enhanced chemical vapor deposition technique. The effects of H₂ flow rate on the microstructure and optical property of the deposited films were investigated. The deposition rate increases firstly and then
decreases with H₂ flow rates increasing, while the crystallization degree of the films increases monotonically. At low H₂ flow rate, the optical band gap increases initially and then decreases, which is determined by the competition of surface reaction between hydrogen etching and dangling bond terminating. At high H₂ flow rate, the relative density of hydrogen bonding existing in the surface of the nano-SiC increases continuously although the total H content in the films reduces. The increase of the nano-SiC grain quantity and the decrease of the grain size make the optical band gap increase further due to the quantum confinement effect.

The surface structure of PbTe epitaxial layers on Cd _0.98 Zn _0.02 Te (111) grown by molecular beam epitaxy was studied by atomic force microscope. It is shown that the surface is dominated by terraces with triangular shape and anomalous spiral steps. In order to clarify the origin of the triangular shape and spiral steps, PbTe/Cd _0.98 Zn _0.02 Te heteroepitaxial layers were investigated by using a high-resolution transmission electron microscope (HRTEM). As a result, it is confirmed that the triangular shape and spiral steps originate from the intrinsic Frank dislocations represented in PbTe/Cd _0.98 Zn _0.02 Te interface. Considering the effect of the kinetics of dislocations, it is
revealed that the strain field arising from dislocations affects the formation of spiral steps. The experiments data are in agreement with the calculations based on elasticity theory and dislocation gliding theory.

Si films were grown on SiC (111) substrate by solid-source molecular beam epitaxy (SSMBE) at different Si/C flux ratios. The structure characteristics of SiC films were investigated by reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscope (AFM) and Fourier transform infrared spectroscope (FTIR). For the sample grown at Si/C flux ratio (1.1:1.0), ring patterns and twin spots are observed in RHEED and the full width at half maximum (FWHM) of the rocking curve is 2.1°. For the sample grown at Si/C flux ratio(2.3:1.0), the Si spots coexist with SiC spots in the RHEED and the FWHM of the rocking curve is 1.5°. For these two Si/C flux ratios, there are voids and rough surface observed in AFM and large strain exists shown in the FTIR spectra. However, for the sample grown at the Si/C flux ratio (1.5:1.0), besides SiC streaks, a (3×3) surface reconstruction can be observed in RHEED and no SiC twin spots are observed. The results of XRD show that the FWHM of the rocking curve is just 1.1°. The AFM results indicate that the surface of the sample is even and there are no obvious voids. While the results of FTIR show that the strain in the
film is small. Therefore, the optimized Si/C flux ratio is 1.5:1.0, and the quality of the film grown at the optimized Si/C flux ratio is the best.

A new kind of b-axis oriented BaTi₂O₅ thin film was prepared on MgO (100) substrates by pulsed laser deposition. The effects of substrate temperature (T _sub) and oxygen partial pressure (P _O2) on the crystal phase and preferred orientation were investigated. The BaTi₂O₅ thin films exhibits (710) or (020) orientation, which depends on the substrate temperature and oxygen partial pressure. On the deposition condition of T _sub=700℃ and P _O2=12.5Pa, the b-axis oriented BaTi₂O₅ film is successfully obtained. The film has a dense and smooth surface, showing an elongated granular texture.

Negatively charged and monodisperse CdTe quantum dots (QDs) with average size of about 5nm were synthesized in aqueous solution using 3-mercaptopropionic acid as stabilizing reagent. Through the electrostatic interactions among the negative surface charges on CdTe QDs, the cationic groups of poly(diallyldimethylammonium chloride) (PDDA) and the anionic groups of poly(sodium 4-styrene-sulfonate) (PSS), ultrathin multilayer of CdTe QDs were fabricated on the pretreated quartz substrate by layer-by-layer electrostatic self-assembly method. UV-Vis spectra, photoluminescence spectra, XPS and AFM were used to characterize the ultrathin films. The results show that there is a linear relationship between the adsorption and the layer numbers of the thin films, indicating that the resultant nanofilms have good quality. The ultrathin films are flatly deposited on the quartz surface with some aggregates of CdTe QDs on it.
The stability and quality of the films can be improved by the introduction of polyelectrolyte multilayers of PDDA/PSS/PDDA between two adjacent layers of CdTe QDs on the substrate. The prepared ultrathin films of CdTe QDs show good photoluminescence property.

A series of AlN/SiO₂ nano-multilayers with different individual SiO₂ layer thicknesses were prepared by reactive magnetron sputtering. The microstructure and mechanical properties of these multilayers were studied by X-ray diffraction, high-resolution transmission electron microscope, scanning electron microscope and nanoindentation. The influence of SiO₂ layer thickness on the microstructure and mechanical properties of AlN/SiO₂ nano-multilayers was studied, and the high temperature oxidation resistance was investigated. The SiO₂ layer is usually amorphous under sputtering condition. Results show that when its thickness is less than 0.6nm, the SiO₂ layer is forced to crystallize into hexagonal pseudocrystal structure and grows epitaxially with AlN, and the multilayers exhibit superhardness effect. With a further increase in its layer thickness, SiO₂ layer transforms into amorphous structure and blocks the coherent growth of multilayers, accompanied with a decline in the film hardness. The results of high temperature annealing test indicate that the oxidation resistance temperature for AlN/SiO₂ nano-multilayers with high hardness is up to 800℃, equivalent to that for the AlN monolayer.
The addition of SiO₂ layer can improve the hardness of multilayers, but it will not remarkably improve the high temperature oxidation resistance of films.

Dy and Ce co-doped lanthanum zirconate composite (La _1.7 Dy _0.3(Zr _0.8 CeZr _0.2 )₂ O ₇, LDCZ) ceramic powders were prepared by the chemical precipitation method. XRD, SEM, differential Scanning Calorimetry (DSC) and TG, were used to analyze the crystallogrphic phase, microstructure and the phase stability of LDCZ. High-temperature dilatometer, DSC and laser thermal diffusivity methods were used to analyze its thermal expansion coefficient (TEC), specific heat and thermal diffusivity. The results show that the compositions of all prepared ceramic powders are in the range of the synthesis of La ₂ Zr ₂ O ₇ with pyrochlore structure, the ceramic powders are amorphous mixed oxide at 120℃, the amorphous mixed oxide is converted to composite oxide when temperature is increased to 900, and the composite oxide is converted to single La　₂　Zr　₂O　₇ with pyrochlore structure at 1200℃. The LDCZ powders keep the pyrochlore structure and there is no phase transformations for LDCZ at high temperatures (～1300℃). The thermophysical results indicate that the thermal expansion coefficient of the LDCZ ceramic is slightly higher than that of conventional Y₂O₃-8wt%ZrO₂ (8YSZ) and the thermal conductivity of the ceramic is 1.28--1.07W/m·K, it is 25% lower than preparing thermal barrier coatings.

A novel composite material based on mixture of samarium-doped ceria (SDC)-carbonate was studied as electrolyte in low temperature solid oxide fuel cells. The phase and microstructures of composite electrolyte were examined by XRD and SEM. The electrical conductivity was investigated by AC impedance spectroscopy at 400--700℃ in different atmospheres. An abrupt change in the conductivity at about 500℃ indicates that different mechanisms affect transfer in different temperature ranges. The conductivity increases with the carbonate fraction above 500℃. The conductivity in reduce atmosphere is higher than that in oxide atmosphere. An anode-supported fuel cell using SDC-carbonate as electrolyte was fabricated and tested. The result shows that all the composite electrolytes exhibit better performance than pure SDC electrolyte. The electrolyte with 20wt% carbonate can achieve the highest power density of 415mW·cm^-2 and an open circuit voltage of 1.00V at 500℃.

SiO/MWNTs anode was prepared by mixing SiO particles with Multi-Walled carbon nanotubes as conductive agent.
The galvanostatic charge-discharge cycling was used to investigate the effects of the type and contents of conducting agents on the electrochemical performances of SiO electrode. The results indicate that the electrochemical performance of SiO is improved obviously by adding MWNTs. The SiO/(20%)MWNTs composite anode shows an initial specific reversible capacity of 1463.9mAh·g^-1, much higher than 582.3mAh·g^-1 for SiO/(20%)AB. The results of SEM and EIS confirm that the excellent cycle performance is attribute to the perfect flexibility and good electric conductivity of MWNTs network, while SiO/AB has larger interparticle contact resistance, which is resulted from the crumbling and conduction network breakage.

Ni ²⁺ -doped V ₂ O ₅ cathode materials were synthesized by liquid deposition process with NiSO₄·6H₂O as dopant. The effects of Ni ²⁺ on the physical and chemical properties of the target compounds were investigated. The material structure, microphology and grain sizes were characterized by XRD and SEM. Galvanostatic method and AC impedance were used to measure the electrochemical performance of the material. The results show that the Ni ²⁺ doping affects the product structure slightly, and it is helpful to reduce the impedance of charge transfer in V₂O₅. With the increase of doping content, the capacitor specific energy increases. With the 2.5% Ni ²⁺ doping content, the highest specific energy of the capacitor is up to 15.6Wh·kg^-1 and coulomb efficiency is 95.12%.

F-doped lithium iron phosphates were synthesized and in~situ carbon coated by two-step solid-state reaction using Fe(Ⅲ) compound as the iron source and polypropylene as the reductive agent and carbon source. The results show that the synthesized powders are near-spherical particles of 50--200nm with the olivine type LiFePO₄ structure. Two-step solid-state reaction inhibits the growth of LiFePO₄ particles more efficient compared with one-step solid-state reaction. The results of electrochemical measurement show that fluorin doping improves the rate capability of LiFePO₄ and decreases the polarization of LiFePO₄ electrode effectively. The discharge capacities of LiFePO_3.98F_0.02/C cathode material are 146mAh/g, 137mAh/g, 122mAh/g at charge and discharge rates of 1C, 2C, 3C, respectively. Cycling efficiency of 99.3% can be obtained after 55 cycles at 1C rate.

Using vapor-phase transformation method, binder-free monoliths of ultrafine ZSM-5 zeolite crystals were prepared by conversion of the preformed bodies of diatomite and silica sol, which mixed with some zeolite seeding directors. The tiny zeolite crystals and units in the seeding directors inducted the conversion of the alumino-silicalite raw materials into intergrown ZSM-5 zeolites, which resulted in binder-free zeolite monoliths. The prepared materials possess enriched porosity, high surface area, good mechanical strength and tunable acidity which can be verified by the characterization. The products have promising applications in catalyst and adsorbent.

The needle-like structured porous mullite ceramic membrane supports were prepared using kaolin, Al₂O₃ and Al(OH)₃ as raw materials by in ~situ reaction sintering. Al₂O₃/kaolin and Al(OH)₃/kaolin mixtures with different contents of AlF₃ additives were selected, respectively. The effects of different aluminium resources and doping amount of the additives on the needle like structured macroporous mullite support formation were investigated. Results show that topaz is formed prior to the formation of needle-like mullite and the needle-like mullite formation is closely related to the topaz content in samples. Formation mechanism of needle-like mullite is vapor-solid reaction mechanism. The needle-like structured porous mullite support with porosity of more than 35% and average pore size of 1.5μm is more easily prepared using the Al(OH)₃/kaolin mixture as raw materials, and it’s quantity increases with the AlF₃ content increasing.

Durra was firstly transformed into carbon template by high-temperature pyrolysis and then converted into biomorphic SiC by infiltration of liquid Si in Ar atmosphere at 1600℃. The purified SiC sample was characterized by X-ray diffraction, scanning electron microscope and mercury intrusion. The results suggest that the sample mainly consist of β-SiC and perfectly replicate the microstructure and morphology of the carbon template. The durra-derived SiC has a mean pore diameter of 91.4μm and porosity of 76.6%, and both of them are similar to those of the carbon template, 88.5 μm and 71.2%, respectively. The specific surface area of SiC is 33.7m²/g, which is less than that of the carbon template, 59.4m²/g. The surface fractal dimension is 2.73 for the SiC sample and 2.70 for the template by analyzing the mercury intrusion data. The durra-derived SiC has characteristics of large grain size and high porosity.

The title new compound Ce₅AgBi₃ was synthesized by arc melting method followed by annealing. The crystal structure refined using Rietveld method and X-ray powder diffraction data shows that it is similar to Hf₅CuSn₃ with space group p63/mcm (No.193). The unit cell parameters are a=b=9.7163(3)A, c=6.6228(2)A and V=541.47(5)A³. The structure is characterized by layers of Ce-Bi net formed by Ce and Bi at 6g position. Ce at 4f position and Ag at 2d position are separated in those two different kinds of Ce-Bi hexagon tunnels along c axes, respectively. Magnetism and specific heat property of Ce₅AgBi₃ are measured using PPMS. Ce₅AgBi₃ is antiferromagnetism and complies with Curie-Weiss law above T_N=3.8K. The calculated moment is 2.67μ_B, fitted well with μ_eff of Ce^3+，which means that the magnetism of Ce₅AgBi₃ is mainly offered by Ce^3+.

Porous calcium silicate (CS) and β-tricalcium phosphate (β-TCP) bioceramics were obtained by sintering polymeric sponges infiltrated with ceramic slurry. They were implanted in rabbit subcutaneous sites and the biological characteristics were investigated. After 1, 2 and 4 weeks implantation, specimens were harvested and analyzed by SPECT, Von Gieson staining, Micro-CT, SEM and EDX. There is no obvious toxic reaction in porous CS ceramics, showing the excellent biocompatibility of CS ceramics. In SPECT scanning, the ROI of CS and β-TCP is (53.95±15.14) and (9.81±3.64), respectively (p<0.01), showing higher vascularization for CS. In Micro-CT analysis, the percentage of residual material volume fraction of CS and β-TCP after 4 weeks implantation is 16.41%±1.96% and 30.72%±0.69% respectively (p<0.01). In semi-quantitative analysis of histological observation, the percentage of residual material in CS is obviously lower than that in β-TCP. These results show that the biodegradation of CS is higher than that of β-TCP. The deposition of the bone-like hydroxyapatite layer after 2 week implantation show good bioactivity of CS in vivo. In conclusion, compared with β-TCP, porous CS bioceramics have superiority in vascularization, ingrowth of new tissue and degradation in early stage. Therefore, porous CS bioceramics may be potential candidates as biocompatible, bioactive and biodegradable scaffolds for hard tissue repair and tissue engineering applications.

The microstructures of nacre layers in H. cumingii Lea Shells and freshwater pearls were investigated extensively via SEM and optical microscope. The results show that besides the normal laminate nacre layers, there are several special structures in H. cumingii Lea Shells, including columnar nacre, needle-like crystals layer and prism crystals layer. In columnar nacre, the thickness of a single aragonite tablet is 1μm, twice more than the thickness of aragonite tablet in normal nacre. However, these special structures are not found in nacre layers of normal freshwater pearls, which has shining surface. The nacre growth in freshwater pearls occurrs in a closed micro-environment of mantle sacs resulting in a uniform structure of nacre layers. The nacreous biocoatings were biofabricated on titanium implants using cylinder mantle sacs and were analysed by optical microscope and X-ray photograph. The results show that the nacreous biocoatings grow along the surface of the titanium implants.

Novel magnetic bioactive glass-ceramics (MGC) in the system MgO-CaO-SiO₂-P₂O₅-CaF₂-MnO-ZnO-Fe₂O₃ were synthesized by doping Mn-Zn ferrite in apatite-wollastonite glass-ceramics (A-WGC). The effect of preparation methods on the magnetic performance and bioactivity of MGC was studied. The results show that apatite, wollastonite, flourapatite and Zn_0.75Mn_0.75Fe _1.5O₄ are the main phases of MGC. Under a magnetic field of 7.96×10⁵A·m^-1, the saturation magnetization of MGC fabricated by different ways ranges from 5.4A·m²·kg^-1 to 5.9A·m²·kg^-1. Mn-Zn doping ferrite decreases the bioactivity of A-WGC. It takes at least 14d for a hydroxyapatite layer forming on the surface of MGC. Comparing with all the materials, the sample synthesized by mixing the heated A-WGC precursors with Mn-Zn ferrite precursor has proper magnetism and best bioactivity.

Mn-modified CaBi₄Ti₄O₁₅ (CBT+x mol% MnCO₃) layer-structured piezoelectric ceramics were prepared by the solid state reaction technology. All samples have the same Curie temperature of 780℃, but the dielectric loss at high temperature is remarkably lowered by Mn addition. With increasing content of Mn, the remnant polarization is slightly decreased; the dielectric constant at room temperature decreases from 173 to 162; and the mechanical quality factor increases from 2700 to 4400. The piezoelectric constant d₃₃ is enhanced from 7 to 14.5. The resistivity of 1.0mol% Mn modified sample is found to be 10⁸ Ω·cm at 500℃, 50 times higher than that of pure CBT. The Arrehenius plot of Mn-modified CBT is fitted by 3 straight lines, while that of pure CBT is fitted by 2 straight lines. The results suggest that the Mn modified CBT is a potential material for high temperature sensing application.

In order to develop an efficient gelcasting technique used for lead free piezoceramics, aqueous gelcasting was applied to prepare 0.94Na_0.5Bi_0.5TiO₃-0.06BaTiO₃(BNBT6) ceramic and its effects on the ceramic microstructure and piezoelectric performance were intensively investigated as well. PMAA-NH4 was used as the dispersant in the process. When the suspension contained 0.5wt% PMAA-NH4 and pH value was adjusted at around 9.2, the BNBT6 suspension was stable with low viscosity (<1Pa·s) and high solid loading (50vol%). The dipping pretreatment was also conducted for pre-drying gelled parts. In the process, the gelled parts were immersed in 10wt% ammonium persulphate solution for 8--10h. After the dipping pretreatment, desiccation and dehydration of the gelled parts without defects became easily controlled. SEM micrographs show that the BNBT6 ceramic prepared by the gelcasting route exhibits homogeneous microstructure and high density. The optimal piezoelectric and dielectric properties are obtained, namely d₃₃=132pC/N; ε_r=1319; tgδ=0.019.

Molybdic acid aggregates were prepared by the reaction of ammonium molybdate with HNO3 and HCl in a coexisting HAc or cetyl-trimethyl ammonium bromide (CTAB) solution, respectively. The results indicate that the size and morphology of as-prepared molybdic acid aggregates and annealed products-α-MoO₃ powder were affected by the concentration of ammonium molybdate, HAc and CTAB. The molybdic acid aggregates with diameter of 1--2μm and length of several decades-micron can be obtained by the reaction of higher-concentration ammonium molybdate with HNO₃ in a coexisting HAc or CTAB solution, repectively. After the as-prepared molybdic acid aggregates are annealed at 500--600℃ for 3h, the nanometer-scaled lamellate and sub-micrometer MoO₃ powder are prepared. In addition, irregular molybdic acid aggregates rods are achieved by the reaction of lower-concentration ammonium molybdate with HCl in a coexisting CTAB solution.