TiSi₂-SiC and TiSi₂-SiC-Ti₃SiC₂ composites were in situ fabricated by spark plasma sintering using commercially available Si, Ti, C and TiC as starting materials. The phase constitutes and microstructures of the composites were analyzed by XRD, FESEM and TEM. It shows that the TiSi₂ grains are larger than 1μm and SiC particles in the range of 200--300nm uniformly distribute
in the TiSi₂ matrix. The hardness, fracture toughness and bending strength of TiSi₂-SiC composites increase with the SiC contents increasing. The introduction of Ti₃SiC₂ enhances the mechanical properties of
TiSi₂-SiC-Ti₃SiC₂ composite greatly. In addition, the introduction
of SiC and Ti₃SiC₂ have little effect on the electrical conductivity and thermal conductivity of TiSi₂ -SiC composites tested at the elevated temperature.

A SiC-WSi₂/MoSi₂ multilayer oxidation protective coating for carbon/carbon (C/C) composites was prepared by pack cementation. Effects of the total content of W and Mo on the microstructure and high temperature anti-oxidation property of the multi-coating were studied by XRD, SEM, EDS and isothermal oxidation test. The results show that with the total content of W and Mo increasing in the pack powders, the as-received multi-coating thickness first increases and then decreases. The multi-coating with 10.0at％ (W and Mo) has a thicker, denser structure and higher content of WSi₂ and
MoSi₂ than those with 0at％, 8.4at％ and 13.1at％ (W and Mo). A stable and dense glassy SiO₂ film can be formed on the coating surface with 10.0at％
(W and Mo) during the oxidation test. The coated specimen with 10.0at％ (W and Mo) has no weight loss after oxidation in air for 315h at 1500℃ and no cracks after thermal cycling between 1500℃ and room temperature for 18 times, which implies that the multicoating has excellent oxidation protective ability and thermal shock resistance.

The carbon felt/carbon (C/C) composites with 2wt％ hafnium carbide were damaged by using a split Hopkinson pressure bar (SHPB) with the maximum impact loading of 137MPa or so, and the effect of dynamic impact damage on ablative properties of the C/C composites was investigated in oxyacetylene flame equipment with high velocity gas. The effect of impact damage on ablative mechanism of the composites was also discussed based on SEM observation. The results show that the linear ablation rate is increased by 118％, and the mass ablation rate is increased by 40％ for the damaged C/C composites than those measured for the undamaged C/C composites.

Carbon fiber needling preform
reinforced C/SiC composites were prepared by “CVI+PIP”combined process.
The densification efficiency, the microstructure and properties of the C/SiC
composites reinforced by carbon fiber needling preform were investigated
compared with 3D woven preform and pre-oxidation PAN fiber needling preform reinforced C/SiC composites. The results show that the densification
efficiency of carbon fiber needling preform is higher than that of 3D
woven preform. Under the same densification processing condition, the densitis of the composites reinforced with carbon fiber needling preform and pre-oxidation PAN fiber needling preform reach 2.08g/cm³ and 2.02g/cm³, respectively, while the density of the composites reinforced with 3D woven preform is merely 1.81g/cm³. The composites reinforced with carbon fiber needling perform exhibits good mechanical properties with flexural strength of 237MPa and shear strength of 26MPa, respectively.

New preceramic polymers-hybrid polyborosilazanes (H-PBSZ) were synthesized and characterized. The ceramization process of H-PBSZ was investigated by TGA, FT-IR, XRD and SEM. The results show that there exist bonds of B-N, Si-N, B-H, N-H, Si-H in the structures of H-PBSZ. With the increase of pyrolysis temperature, the bonds contained H atoms decrease till they disappear. The ultimate product is a mixture comprised of BN and Si₃N₄ . The loss of weight in the process of pyrolysis mainly occurs between 100℃ and 400℃, and the ceramic yield is about 83wt％. The pyrolytic product is crystallized as the temperature increases. The products pyrolyzed at 800℃ are almost amorphous with mainly spherical particles, while those pyrolyzed at 1600℃ are well crystallized, and h-BN crystal flakes and α-Si₃N₄ grains can be observed by SEM.

Carbon fiber reinforced silicon carbide matrix (C/SiC) braking materials were prepared by a reactive melt infiltration method. The microstructure characteristics of SiC were studied by means of optical microscope, scanning electron microscope and transmission electron microscope in combination with component analysis by X-ray diffraction. Results show that β-SiC zone usually forms inside the short-cut fabric, around the needling fibers, and among the fiber bundles in the non-woven web. Residual Si locates among SiC grains. In C/SiC composites, there exist two different areas of SiC, one is coarser β-SiC grains between 5--15μm at the SiC-Si interface. and the other is a zone of a fine grained β-SiC layer with dimension of about 100nm at the SiC-C interface.

Al-doped and un-doped 6H-SiC crystals were grown by physical vapor transport (PVT) method. Raman spectra were measured from room temperature to 400℃. The Raman requencies were shifted to lower wavenumber and Raman peaks were broadened with increasing temperature for both samples due to thermal expansion and optical phonons decay. Free carrier concentration in Al-doped sample was increased with increasing temperature due to increasing of the plasma concentration, which correspondingly enhanced more strong coupling interactions among LO phonons, plasma, and free carriers. Therefore, the intensity of A1 (LO) mode for Al-doped sample decreased obviously and maintained unchangeable for un-doped sample. The Al activation behavior and its contribution to free carriers in high temperatures were analyzed theoretically and demonstrated experimentally.

Silicon carbide (SiC) powder was synthesized from liquid silicon in one step at the presence of a catalyst bar consisting of silica and carbon. The silicon carbide powders were formed by the carbothermal reaction between liquid silicon and gaseous CO, and the average particle size (D₅₀) of the as-prepared silicon carbide powder was 0.41μm. The powder was characterized by XRD, SEM, particle size analysis and elemental analysis. The mechanism for the formation of the silicon carbide powder was discussed.

Neodymium zirconate (Nd₂Zr₂O₇, NZ) and CeO₂-Nd₂O₃-ZrO₂ (NCZ) ceramics were synthesized by the chemical precipitation method. The chemical compositions of the powders were nalyzed by means of Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Differential Scanning Calorimetry (DSC), TG and XRD were used to analyze the crystallogrphic phase and the phase stability of NCZ. The Hall flowmeter was performed to determine the flowability of NCZ powder. High-temperature dilatometer, DSC and laser thermal diffusivity methods were used to analyze its thermal expansion coefficient (TEC), thermal conductivity. The results show that the compositions of all prepared ceramic powders are in the range of the synthesis of Nd₂ ZrO₇ with pyrochlore structure, the ceramic powders are amorphous mixed oxide at 120℃, composite oxide at 900℃, Nd₂ ZrO₇ with pyrochlore structure at 1200℃. The NCZ powders keep the pyrochlore structure and there is no phase transformations for NCZ at high temperatures (～1300℃). The flowability of NCZ powder sintered at 1400℃ is improved clearly. TEC of the NCZ ceramic is slightly higher than that of conventional Y₂O₃ 8wt ZrO₂ (YSZ) and the thermal conductivity of the ceramic is much lower than that of YSZ, which indicates that NCZ may be an excellent material for preparing thermal barrier coatings.

Polycrystalline cubic boron nitride (PcBN) samples were obtained by sintering cBN and aluminum micro-powders in volume ratio of 7:3 at high temperature (1300--1500℃) and high pressure (5.5GPa). The identification and the morphology of phases, and the distribution of elements in PcBN samples were studied by using X-ray diffraction (XRD), transmission electron microscope (TEM), selected-area electron diffraction (SAED), and energy dispersive X-ray spectrometry (EDS). Results show that Al does not react with cBN at 1300℃. When the temperature is increased to 1400℃, Al can react with cBN to form AlN and AlB₂, and the temperature is increased to 1500℃, the amount of products increases. TEM and EDS analyzing results indicate that Al atoms diffuse into surface layer of cBN particle, and B atoms diffuse into Al zone, forming new phases AlN and AlB₂.

Preparation of Bi₂O₃-ZnO-Nb₂O₅(BZN) ceramic ink for Ink-Jet printing was studied with an aqueous, multifunctional organic solvent-sokalan PM70. The effects of different content of PM70 and the solid content BZN powder on the stability and viscosity of suspension liquid were discussed, and rather stable ink with high solid content was obtained. A planar capacitor was printed successfully with the prepared ink by the iP-210 Personal Plotter controlled by MD-E-201H. The influence of controlling parameters on the Ink-Jet printing was also dealt with. The thickness distribution of printed images was measured by Rodenstock RM600S. The experiment indicates that when the content of PM70 is 3.2wt％, the stability of ceramic ink is much more stable with the highest solid content of 48.8wt％. A better practical printing result will be obtained in the condition that drive voltage is 10V, the pulse width is 1.5 and the pulse period is about 800μ s.

A series of nanoparticle SrTiO₃ samples were simply synthesized by hydrothermal method using layered titanate nanotube and Sr(Ac)₂ as precursors. The samples were characterized by using powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence (PL), Raman spectroscope and specific surface area measurement. The measurement results show that the diameter distribution of prepared SrTiO₃ nanoparticles with disordered pores is mainly in the range of 10--30nm, and with the increase of reaction temperature or reaction time, diameter of the nanoparticles increases, whereas specific surface area and photocatalytic activity for degradation of methylene blue decrease.

The effects of Bi_0.5Na_0.5TiO₃ (BNT) doping on the dielectric properties and microstructures of BaTiO3 (BT)-Nb2O5-ZnO ternary system were investigated. The Δ C/C_25℃ values at low temperature (-55℃) decrease with increasing BNT content, but the Δ C/C_25℃ values at high temperature (150℃) and the Curie temperature (T_c) show continuous enhancement. BaTiO₃ ceramic doped with 1.0wt% and 2.5wt% BNT are satisfied with the EIA X8R specification. SEM indicates that the BaTiO₃ ceramics are composed of fine grains and secondary phase grains. Moreover, the proportion of the secondary phase grains increases as BNT contents increase. XRD analyses prove that the fine grains are BaTiO₃ and the secondary phase grains are identified to be CaB₂Si₂O₈ and NaBiTi₆O₁₄. The formation of the strip-shaped secondary phase of CaB₂Si₂O₈ and NaBiTi₆O₁₄ which alters the internal stress system of BaTiO₃ ceramics is presumed to be the factor that shifts the T_c to higher temperature and improves the temperature characteristic of BaTiO₃ ceramics.

The magneto-electric behaviors of La_0.67-xNd_xSr_0.33MnO₃ system were studied by the measurement of M-T curve, ESR curve, infrared spectra, Raman spectra, ρ-T curve and MR-T curve of the La_0.67-xNd_xSr_0.33MnO₃ system (x=0.00, 0.10, 0.20, 0.30, 0.40). The experiment result shows that with the Nd doping increasing, the magnetic structure of the system transforms from the long-range ferromagnetic order to spin cluster glass state; for the samples with x=0.30 and 0.40, the phase separation occurs at the temperature high above T_c; The transport property exhibits change with the Nd doping increasing. Magneto-electric behaviors of the system and CMR effect attributes to lattice effect and interface tunneling effect relating to the spin.

A series of multilayers of CoFeB-SiO₂ was fabricated by using DC/RF magnetron sputtering, and then annealed in vacuum at different temperatures. The results show that microstructures and electromagnetic properties of the CoFeB-SiO₂ multilayer films can be altered by varying the volume fraction of SiO₂ and the annealing temperature. High permeability along with high magnetic loss in the GHz frequency range is achieved in the optimized discontinuous multilayer films. Both real and imaginary part of the complex permeability are larger than 260 at 1.5GHz for these films, and the resistivity is as high as 1.38mΩ·cm. The CoFeB-SiO₂ multilayers are supposed to serve as the microwave absorbers in GHz range.

The doped manganites Pr_2/3Sr_1/3MnO₃ (PSMO)film was prepared by the pulsed laser deposition method. The spin transport properties of the film induced by the magnetic field, laser and the current field were investigated. In ferromagnetic metallic state, the laser irradiation results in the increase of the resistance, which is attributed to the photoinduced demagnetization effect. But the magnetic field and the current induce the resistance decrease because the magnetic field and the current align the magnetic moments of the nearest Mn ions and enhance the double-exchange effect. In the paramagnetic
insulating phase, the three external fields induce the decrease in the resistance, which is due to the field-induced delocalization of the small polarons.

Lithium cobalt oxides (LiCoO₂) powders were synthesized by self-propagating high temperature synthesis using urea as fuel. XRD, SEM and electrochemical method were used to investigate the effects of mole ratio of urea to Co, mole ratio of Li to Co, combustion temperature, annealing temperature and the annealing time on the performance of LiCoO₂. The results show that self-propagating high temperature synthesis is beneficial to form the layer structure of LiCoO₂. The optimum condition is obtained as follows: molar ratio of urea to Co is 1:1, molar ratio of Li to Co is 1:1, combustion temperature and annealing temperature are 800℃ and annealing time is 2h, Under the optimum condition, the discharge capacity of LiCoO₂ is 155mAh/g, and its capacity retention is 95% after 10cycles.

The purpose of this study was to explore the synthesis of finer Al-substituted Ni(OH)₂ particles by means of homogeneous precipitation method and to investigate its’ micro-morphology, crystal structure, chemical composition and electrochemical performance at high temperature. The results show that a stabilized α-phase is obtained for the experimental substance and the particles are spherical agglomerates of fibrous nanometer scale crystallites. The approximate chemical composition of the product can be described as Ni_0.70Al_0.18(OH)_1.6(CO₃)_0.1(SO₄)_0.07·(H₂O)_0.6. In the experimental MH-Ni batteries, Al-substituted Ni(OH)₂ anode displays high charging efficiency and good cyclic stability with comparatively high oxygen evolution potential at 60℃. Compared with the behavior at 25℃, its discharging capacity at 60℃ is decreased by 15mAh/g. Moreover, after electrochemically cycled at 60℃ for 95 times, the structure of Al-substituted Ni(OH)₂ remains mainly α phase, showing good structural stability.

The composite cathode material of Li_0.97+δTi_0.03Fe_0.97Mn_0.03 PO₄/C was synthesized by carbothermal reduction of FeFe_0.97Mn_0.03 PO₄ which was prepared by co-precipitation method. The samples were characterized by X-ray diffraction, scanning electron microscope, FTIR absorption spectra, and their electrochemical performances were investigated in terms of rate discharge and cycling behavior. The results show that Li_0.97+δTi_0.03Fe_0.97Mn_0.03 samples are simple pure olive-type phase, and the particles are homogeneous with average particle size of about 1μm. The ion dopants of Mn⁴⁺ and Ti⁴⁺ do not affect the structure of the material. Compared with LiFePO₄/C, the composite compound Li_0.97+δTi_0.03Fe_0.97Mn_0.03 exhibits good electrode properties with discharge capacities of 134.0, 133.4, 130.1 and 127.2mAh·^g-1 at 0.2, 1, 5 and 10C rates, respectively. In addition, it shows excellent cycle stability at different rates.

sodium fast ion conductors of NaLaS₂ and NaLaS_1.5Se_0.5 were prepared by high temperature solid state reaction at 750℃. X-ray powder diffraction analysis confirms that NaLaS_1.5Se_0.5 is isostructural to NaLaS₂ and NaLaSe₂
(space group FM3-M). Their ionic conductive properties were investigated by AC impedance spectroscopy in the frequency range of 0.1Hz--100kHz at different temperatures. The conductivity of NaLaS_1.5Se_0.5 is higher than that of NaLaS₂ at the same temperature. NaLaS ₂ shows conductivity of 3.65×10^-5S·cm^-1 at 30℃ and 6.23×10^-5S·cm^-1 at 90℃, respectively; while NaLaS_1.5Se_0.5 displays higher conductivity of 8.11×10^-5S·cm^-1 at 30℃ and 1.37×10^-4S·cm^-1 at 60℃, respectively. This is probably due to the stronger polarization power of Se^2--, the larger radius of Se^2-, and subsequently the enlargement of local lattice.

Bi₂Te₃ nanorods were successfully prepared through chemical reduction at low temperature. In this process, Bi(NO₃)₃·5H₂O and TeO₂ were used as reactants, NaBH4 was used as reductant, and Brij56 (HO(CH₂CH₂O)₁₀C₁₆H₃₃) was used as regulator of crystal growth. EDTA was added into the solution to prevent the hydrolyzation of reactants at about pH 7.0. As-synthesized sample was characterized by X-ray diffraction and X-ray fluorescence, scanning electron microscope, transmission electron microscope, and high-resolution transmission electron microscope. Results show that Bi₂Te₃ nanorods are single crystalline, 30nm in diameter and 400nm in length. The temperature and the concentration of the surfactant Brij56 have obvious effects on the morphologies and sizes of synthesized sample. The growth mechanism of Bi₂Te₃ nanorods is also discussed.

Single-grain bulks of Gd-Ba-Cu-O, (SmGd)-Ba-Cu-O and (SmEuGd)-Ba-Cu-O superconductors with high performance were successfully fabricated via two-step cooling method and top-seeded-melt-growth in the ambient atmosphere. The trapped field distributions at 77K were perfect symmetric, and the maximum value of trapped field for (SmEuGd)-Ba-Cu-O sample (φ18mm) reaches 0.34T, which is comparable with that obtained through OCMG method. The effects of post-annealing in Ar (ArPA) are different for the three LRE-Ba-Cu-O systems. For Gd-Ba-Cu-O system, ArPA cannot improve the superconducting properties. For (SmGd)-Ba-Cu-O and (SmEuGd)-Ba-Cu-O systems, however, their superconducting performances can be enhanced by appropriate ArPA treatment.

BaO-Al2O3-SiO2(BAS) glass-ceramics with stoichiometric and off-stoichiometric celsian composition were fabricated. Crystallization characters of two groups of BaO-Al₂O₃-SiO₂ (BAS) glass-ceramics were investigated by differential scanning calorimetry (DSC), X-ray diffraction(XRD), isoconversional method and multiple linear regression method. The autocatalytic kinetic model (Sest\acute ak-Berggren function) was found to be the most proper description of the studied processes for all glass investigated. Doping with ZrO₂ or increasing mass fraction of BaO accelerates the crystallization process of hexagonal-BaAl₂Si₂O₈ in BAS glass-ceramics with stoichiometric celsian composition whose viscosity is high. Moreover, the lower the temperature gets, or the higher the crystallinity gets, the more obvious the accelerating effect gets. While doping with ZrO₂ decelerates the crystallization process of hexagonal-BaAl₂Si₂O₈ in BAS glass-ceramics with off-stoichiometric celsian composition whose viscosity is low. Moreover, the higher the temperature gets, the more obvious the decelerating effect gets.

A borosilicate bioglass in Na₂O-CaO-SiO₂-P₂O₅-B₂O₃ system is a bioactive and biodegradable material for tissue engineering. In this study, the bioactive porous scaffolds with three-dimensional interconnection were fabricated by replication technique, using borosilicate bioglass powder to form slurry with ethanol as solvent and ethyl-cellulose as additive. The compressive strength of scaffolds increases from 0.03MPa to 0.36MPa by adjusting the slurry load, the solid concentration and the ethyl-cellulose concentration in the slurry, while the pore size of scaffolds remains in the rangeot 300--500μm and the porosity maintains over 80%. According the analysis on Cellular Structure Model, it is suggested that employing high strength glass and optimizing slurry composition are effective approaches to improve cellular structure and increase scaffold strength. The compressive strength of another borosilicate glass scaffolds made from Na₂O-K₂O-MgO-CaO-SiO₂-P₂O₅-B₂O₃ system can reach 5--8MPa based on the theory. These experiments show that the replication technique is a promising way to prepare bioglass scaffolds.

A biodegradable silica-based xerogel with nano-scale mesopores was synthesized by using improved sol-gel process, and its hemostatic properties were investigated. The phase state, chemical structure, surface morphology, specific surface areas and mesoporous structure of the synthesized silica-based xerogels were measured systemically by means of X-ray diffraction (XRD), infrared spectrum (FTIR), transmission electron microscope (TEM), and N2 adsoption-desoption (BET) techniques, respectively. The effects of the silica-based xerogel on intrinsic and extrinsic blood clotting systems were examined through the activated partial thromboplastin time (APTT) and prothrombin time (PT) tests in ~vitro, respectively. The hemostatic performance of the prepared silica-based xerogel was evaluated at the rabbit’s ear side veins compared with a traditional hemostatic dressing (Yunnan Baiyao). The results reveal that the non-crystalline silica-based xerogel with 901.17m²/g specific surface areas and 3.255nm in apertures is obtained after calcining at 600℃. The silica-based xerogel facilitates both of the intrinsic and extrinsic clotting activities significantly. The silica-based xerogel has good hemostatic effect on the rabbit’s ear side veins which is better than that of the Yunnan Baiyao.

In order to solve the uneven distribution of hydroxyapatite (HA) crystals in chitosan (CS) matrix and the weak bonding between HA crystals and CS molecules in HA/CS hybrids, the hydrothermal treatment technology and in~ situ precipitation method were employed to prepare nano-HA/CS hybrids. The obtained samples were characterized by scanning electronic microscope (SEM), Fourier Transmission Infrared Spectrometer (FT-IR), X-ray diffractometer (XRD) and Thermogravimeter (TG). The results show that the obtained hybrids prepared in the different hydrothermal condition are composed of CS crystals and low-crystallinity nano-HA crystals. And the CS and HA crystals in the hybrids have the trend of growing along C axis. Moreover, a strong bonding between the CS molecules and HA crystalline is formed in the hybrids and the bonding strength increases with increasing hydrothermal treatment temperature. When the hydrothermal treatment temperature is up to 100℃, the bonding strength reaches the maximum.

The structure and mechanical properties of silica sponge spicule found in China Bo-hai were studied. The results show that this spicule has the complex hiberarchy: the first tier is nano silica particles; the second tier is the sub-rounds within one silica round; the third tier is silica rounds composed of several parallel sub-rounds; the fourth tier is homocentric round structure with alternant deposition of silica and organic matrix. The flexural strength of this spicule is 394.34GPa, the flexural modulus increases with the growth direction of rounds. The cross-sectional hardness is 2.933GPa, and the cross-sectional Yang’s modulus can reach 33.308GPa.

The aim of this study is to investigate the role of surface roughness of carbon/carbon (C/C) composites on osteoblasts morphology, adhesion and proliferation. C/C composites were prepared by chemical vapor infiltration and three different values of surface roughness were created by treatment with two kinds of grinding paper and mechanical polishing. The
surface roughness of C/C composites was measured by Talysurf profilometer, and cell culture was performed with MG-63 osteoblasts. The adhesion rate, morphology and proliferation rate were assessed. The results show that the adhesion rate increase and the proliferation rate decrease with the increase of roughness. The orientation of the osteoblasts is affected by the roughness, the higher the roughness, the greater the effect. As surface roughness increasing, the morphology of the osteoblasts changes from shuttle and strip shape to slice shape.

Fe-doped SnO₂ films were grown on Si (100) substrates at 270℃ by reactive magnetron sputtering. The sputtering atmosphere was a mixture of argon and oxygen. The samples were prepared under three different oxygen partial pressures. XRD, AFM, VSM were used to investigate the crystalline structure, surface morphology and room temperature ferromagnetism (RTFM) of the samples, respectively. The film deposited under oxygen partial pressure of 0.12Pa exhibits a clear ferromagnetism at room temperature. The chemical composition of the film is Sn_0.975Fe_0.025O_2-δ, and the saturated magnetic moment is about 1.8μ_B/Fe. The microstructure and element distribution of this sample were examined by HRTEM and EDS, respectively. It shows that the films are composed of tetragonal rutile SnO2 nanocrystals with diameter of 3--7nm. Fe atoms are uniformly distributed in the films. No Fe metallic clusters or iron oxides are observed; the measurement of the resistivity indicates insulating characteristic of the film, therefore RTFM of the film can not be attributed to secondary phase or spin-charge carriers interaction. It shows that RTFM is closely related to a great number of structural defects in the film.

Ag/SiO₂ multilayer thin films were prepared by RF magnetron sputtering. The Ag nanoparticles diffuse towards and mostly assemble near the surface of the Ag-SiO₂ films via rapid thermal treatment. Ag nanoparticles with different shapes can be obtained by changing the thickness of Ag and SiO₂ layers. It is found that the Ag particles with sharper edges and wider terrace between steps have more electrons at Fermi level. Accordingly, the intensity of resonance absorption is obviously enhanced.

High k dielectric Er₂O₃ were deposited on p-type Si (100) substrates by reactive evaporation using metallic Er source at room temperature in an oxygen atmosphere. The composition of the films is determined to be stoichiometric. X-ray diffraction, reflection high energy electron diffraction and high resolution transmission electron microscopy tests reveal
that the films are amorphous even after thermal annealing at 700℃. The films have very flat surface after high temperature annealing. The dielectric constant of Er₂O₃ films is 12.6, an effective oxide thickness of 1.4nm is achieved, with a low leakage current density of 8×10^-4 A/cm² at electric field of 1MV/cm after annealing. The obtained results indicate that the amorphous Er₂O₃ film is a promising candidate for high k gate dielectric in Si microelectronic devices.

Low resistivity transparent conducting Zn_xCd_1-xO films were deposited on flexible Polyethylene Terephthalate(PET) substrates by DC magnetron sputtering. Structural, electrical, and optical properties of the films with different Zn concentrations were investigated. XRD results show that for x0.5, the structure of the film is in CdO phase, while for x>0.5, oriented ZnO phase is dominant. Hall results shows that the Zn_xCd_1-xO films has very high carrier concentration when x≤0.5, and the electrical resistivitiy of the films is at the order of 10^-3Ω·cm. Carrier mobility shows a maximum value at x=0.5. The transmittance of the Zn_xCd_1-xO films in the visible range is much higher than that of pure CdO film. It’s concluded that x=0.5 is the optimal value at which low electrical resistive, high visible transmittance Zn_xCd_1-xO films can be deposited at low temperature on flexible substrates.

Vanadium oxide thin films with thickness of 80nm, 440nm and 1μm were deposited on normal glass substrate by reactive DC magnetron sputtering method. The surface morphology, structural feature and crystallization were studied by atomic force microscope (AFM), scanning electron microscope (SEM) and X-ray diffraction (XRD). The results reveal that the grain size and the crystallization state of the thin films are affected by the thickness of thin films. The grain size increases and the crystallization is enhanced with the film thickness increasing. The growth of the thin film demonstrates an obvious “columnar” preferential growth perpendicular to the glass substrates. Analyses of the square resistance and its temperature dependence demonstrate that the thickness of the films plays an important role on the electric properties of vanadium oxide thin films. With the thin film thickness increasing, the square resistance decreases, the temperature coefficient of square resistance increases, width of the hysteresis loop turns to broad, and the metal-semiconductor phase transition becomes obviously.

N/I silicon thin films were deposited on amorphous silicon thin film coated quartz substrate by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD)system at low temperature, and subsequently annealed by two-step rapid thermal processing (RTP). Through Raman scattering, X-Ray diffraction (XRD), scanning electron microscope(SEM) and transmittance electron microscope (TEM) measurement, the crystallization and morphologies of the sample were investigated. The results show that the crystallinity of the N/I silicon thin films reaches about 94% after being annealed. The cross sectional morphology of the N/I silicon thin films is of columnar grains and the average grain size of the sample is about 30nm while the biggest grain cluster is about 1.5μm in landscape orientation.

A superhydrophobic surface originated from strawberry-like or quincunx-shaped composite silica particles modified with fluorosiloxane was obtained. Different kinds of silica particles and fluorosiloxane were used for controlling surface morphology and chemistry, respectively. The dual size particles are obtained by utilizing the graft of different modified silica particles with epoxy functional group and amine functional group. This makes the surface of film form a composite interface to have irregular binary structure which plays an essential role in trapping air between the substrate surface and the liquid droplets to be necessary for high contact angle and low contact angle hysteresis. The maximum contact angle for water on the composite-paticles film is about (174.2±2)°　and the contact angle hysteresis is close to 0°. It is shown that the hierarchical irregularly structure with a low roughness factor and high air-trapped ratio is indispensable for superhydrophobic surface by comparing the surface morphologies, roughness and the wettability on the surface of films containing different structural silica particles.

CdS quantum dots (QDs) of 2.5nm were prepared using G4.5 PAMAM dendrimer templates and characterized by HRTEM and EDS. The aging of synthesized QDs stored in the dark at room-temperature was studied through UV-vis and PL spectrophotometer. The width at half-maximum of the peak (WHM) of the UV-vis and PL spectra becomes narrower, meanwhile the PL intensity increases obviously during the first 5d. Afterwards, the WHM gets broader and the PL intensity decreases slowly during the following 6 months. The results suggest that CdS QDs show a size-focusing growth within the first 5d, but a size-defocusing growth in the following 6 months. However, the increment of CdS QDs size is less than 0.3nm, and the decrement of PL intensity is about
22% after 6 months of aging. The excellent resistance to aging of CdS QDs is attributed to the coordination and template effects of PAMAM dendrimers.

A series of Lu₂O₃ nanopowders co-doped with Yb³⁺ and Ho³⁺ were synthesized by co-precipitation method. The Yb³⁺ concentration is 1mol% and the Ho³⁺ concentration ranges from 0.5mol% to 10mol%. The Stokes and Anti-Stokes spectroscopic
properties of the prepared nanopowders were investigated, together with the relative intensities of Stokes and Anti-Stokes PL spectra dependence on the powders calcined at different temperatures. Strong green emissions were observed under the excitation of 447.5nm (Xenon Lamp) and 980nm (Laser Diode), respectively. Concentration quenching occurrs with the increase of Ho³⁺ concentration. Power studies reveal that a two-photon process is involved in the Anti-Stokes emissions and the possible upconversion mechanisms are energy transfer from Yb³⁺ to Ho³⁺. Concentration quenching and energy transfer process are confirmed by the decay time of the ⁵F₄, ⁵S₂ level under the excitation of different pump wavelength.

Visible-light-driven nitrogen-doped titanium dioxide (N-TiO₂) was synthesized by the method of coprecipitation, in which titanium tetrachloride was used as Ti-precursor and the mixed solution of ammonia and hydrazine hydrate as nitrogen resource. Effects of pH values on the physicochemical properties and the activities of the as-prepared N-TiO₂ catalysts were studied. The obtained photocatalysts are found to be of anatase phase, higher specific area, mesoporous structure and visible response by means of XRD, BET and UV-vis spectra analysis. With increasing pH values, the intensity of anatase (101) peaks enhances, and the crystallite size increases, while the BET specific area decreases. The doped impurities are found to be NO_x species,
which are confirmed by XPS. Minor band-gap narrowing and the visible-light response are due to nitrogen doping. The experiments of photodegradation of 4-chlorophenol show that the degradation ratio (39.65%) of the catalyst prepared at pH=3.5 is the highest under visible light irradiation. The photocatalytic activity decreases when pH values increase. Under UV light
irradiation, the catalyst prepared at pH=5.5 has the highest photocatalytic activity, while that derived from pH=9.5 has the lowest.

The necklace-like TiO₂ nanoparticles were prepared by a sol-gel polymerization and subsequent calcinations. The aggregates of hydrogelator, tetraethylammonium 3-{[(2S)-2-(octadecylamino)-3-phenylpropanoyl] amino} butyrate (abbreviated as TC₁₈PheBu) in aqueous solution were used as the templates and tetrabutyl titanate (Ti(OBu)4) was used as the source of titanium in the preparation of necklace-like TiO2 nanoparticles. The images of FE-SEM indicated that the average diameters of TiO₂ nanoparticles were in the range of 200--400nm. The formation mechanism of necklace-like TiO₂ nanoparticles was discussed
by FT-IR analysis, which indicated that the necklace-like TiO₂ nanoparticles were formed through the electrostatic interaction between positive charged TC₁₈PheBu and negative charged oligomers formed by the hydrolysis of Ti(OBu)4. The XRD analysis indicated that the TiO₂ nanoparticles were in the form of anatase crystals.

Micro-coiled carbon fibers were prepared by a catalytic chemical vapor deposition method, and treated in an argon atmosphere at 2500℃. Scanning electron microscope (SEM), Raman spectroscope and X-ray diffraction (XRD) were performed to characterize morphologies and microstructures of the non-graphitizated and graphitizated micro-coiled carbon fibers, and graphitization mechanism was discussed preliminarily. The results reveal that micro-coiled carbon fibers are purified prominently, morphologies of micro-coiled carbon fibers is similiar to the original fibers, and microstructures of micro-coiled carbon fibers are more regular after the graphitization treatment. The interlayer spacing d₀₀₂ (0.3626--0.3378nm) decreases,
graphitization degree, L_c, mean size of crystal in the c-direction(1.6404--3.8590nm) and L_a, mean size of crystal in the a-direction(2.04--7.21nm) increase.

Cuprous oxide/ carbon nanotubes (Cu₂O/MWNTs) composite superfine spheres were fabricated in situ by solution method. The products were characterized via scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction pattern (XRD), UV-vis absorption spectrum and differential scanning calorimetry (DSC). The results show that the MWNTs are
embedded in cuprous oxide spheres homogeneously. Compared with pure Cu₂O particle, the absorption peak of composite spheres has a tendency of blue shift, and the temperature of high temperature decomposition of ammonium perchlorate (AP) is further decreased by 11.5℃ when composite spheres act as the catalyst. In addition, the main influence on morphology and the formation mechanism of composite spheres are investigated. Results suggest that the gelatin play a key role in forming spheres and polyethylene glycol have great impact on the uniformity of spheres size.

Aminopropyl groups were used to functionalize the pore channels of periodic mesoporous organosilicas(PMOs) by the post-grafting method. The final materials were investigated by means of XRD, TEM, solid-state NMR, N₂ adsorption and Elementar Analysis. The results show that bridging groups in the framework do not cleave and amino groups are attached covalently to the pore wall of periodic mesoporous organosilica after functionalization. The mesoscopic order remains good with increasing aminopropyl groups coverage up to 25mol%. The surface area, pore volume and pore size tend to decrease as the concentration of APTMS increases, but the materials with 25mol% aminopropyl groups still preserve a desirable pore structure, with surface area of 604m ²·^-1, pore volume of 0.62cm³·^-1 and sharp pore size distribution centered between 4.5nm and 5nm. Aminopropyl-functionalized PMOs facilitates absorption of (HAuCl)-complex.

The effect of initiator systems on the gelation process of alumina slurry was studied. The gel former system based on the free-radical polymerization of acrylimade(AM) and N,N’-menthylene-bis-acrylamide(MBAM) was used in gelcasting of alumina. Three initiator systems, ammonium persulfate(APS), ammonium persulfate and N,N,N’,N’,-tetramethylethylenediamine redox system (APS-TEMED), and 2,2’-Azobis[2-(2-imidazolin-2-yl)propane] dihydrochlorid(AZIP·2HCl), were used to initiate the polymerization of AM and MBAM. The effect of initiator systems on the polymerization process was investigated by the elastic modulus change during polymerization. Among these initiator systems, idle time of polymerization initiated by AZIP·HCl shows remarkable dependence on temperature while the elastic modulus of polymer gelled is slightly increased with increasing temperature from 40℃ to 50℃. Elastic modulus in gelation process of 50vol% alumina slurry initiated by ZIP·2HCl shows that both temperature and initiator concentration have strong effect on the gelation process, by which the gelation process can be controlled. Compared with gelation initiated by other initiators, gelation of 50vol% alumina slurry initiated by AZIP·2HCl gains modulus of 2.3×10 ⁶Pa at 50℃, which is higher than these by APS(1.58×10⁶Pa) at 55℃ and APS-TEMED(1.58×10⁶Pa) at 25℃.

GaN, III-V, SiC and related alloys on Si substrates becomes a hot research area recently. GaN and SiC have wide applications in photonic and electronics, such as high power, high speed devices and LEDs UV detectors etc. Silicon substrates are low cost, available in large diameters and have well characterized electrical and thermal properties. Despite these advantages，silicon has not been popular as a substrate material for GaN, SiC and III-V growth due to several problems mainly related to the thermal and lattice mismatches. Silicon attracted attention as a substrate material for GaN growth when the first MBE grown GaN LED on Si was demonstrated in 1998 from IBM group. Recently. using AlN and AlGaN buffer layers for GaN and SiGe buffer layers for III-V materials growth on Si, the thermal stress and lattice mismatch can be reduced significantly and over 1µm crack free GaN epi-films can be grown on 6 inch Si(111) wafers. High power blue LED on Si have been demonstrated by AZZURRO, in Germany. The power devices on Si also have been made by Nitrinex in USA. The super high power devices on Si are still in instigation. In 2007, UK government set up a solid-state lighting program, which focus on developing GaN based LED on 6 inch Si substrates. On the other hand, continued physical scaling of mainstream silicon CMOS technology has boosted the performance of the Si devices in the past 40 years. Increasing the drive current at low-bias voltage to reduce the gate delay for 30 nm and beyond low-power logic application requires devices possessing channel materials with higher carrier mobility. III-V compounds with mobility as high as 80000 cm²/Vs are possible solutions for Si CMOS beyond 30nm，such as InSb, InAs, and InGaAs. In 2007, DARPA/MTO started a program for compound semiconductors on silicon (COSMOS) focusing on high speed chips embedded in silicon CMOS. The first international symposium deals with “Advances in GaN, GaAs, SiC and related alloy on Si substrates” in MRS 2008 spring meeting will be held on March 24 -28, 2008 in San Francisco, USA.