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Ba2Ti9O20 ceramics were prepared with different additives of B2O3 by liquid coating method and solid phase mix method. The sintering behavior, phase structure and dielectric properties of ceramics were investigated by X-ray diffraction, scanning electron microscopy and inductance-capacitance resistance analysis. The liquid coating method can reduce the amount of sintering aid and minimized the negative impact of sintering aid on dielectric properties. A ceramic composite which could be sintered well at 900℃ for 3h and showed good dielectric properties of εr=42,tanδ=0.002 and TCF=-4ppm/℃（1MHz）was obtained when 1.0mol/l H3BO3 was added to the Ba2Ti9O20 ceramic.

ZnNb2O6 ceramics doped with V2O5 were prepared by conventional mixed solid method. The effects of V2O5 addition on the microstructure and the microwave dielectric properties of ZnNb2O6 ceramics were investigated systematically. The sintering temperature of ZnNb2O6 ceramics with 1.0wt.% V2O5 addition can be effectively reduced from 1150°C to 1050°C. The secondary phase ZnV2O6 was observed in sintered samples with V2O5 addition content higher than 1.0wt.%. For 0.3–3wt.%V2O5-doped ZnNb2O6 ceramics, The dielectric constants (εr) of densified samples were higher than that of undoped ZnNb2O6 ceramics. The temperature coefficient of resonant frequency (τf) were shifted toward zero direction with the increase of V2O5 addition, However, the dielectric loss (tanδ=1/Q) increased. The 1.0wt.% V2O5-doped ZnNb2O6 ceramics sintered at 1050°C for 3h have the optimum microwave dielectric properties: εr=28, tanδ=0.0006 and τf=-42.5 ppm/°C.

The flow field of lubrication film under the bottom of the slipper is analyzed particularly. The velocity in different points of the lubrication film on the bottom of the slipper is solved based on the premise that the rotation and self-rotation of the slipper has been taken into account of. This paper puts forward that regular concaves converging along the radial direction be set up in the cyclic zone of slipper’s bottom surface to enhance the lubrication effect and improve the overwear situation in the peripheral parts of the slipper.

The sintering behaviors and microwave dielectric properties of the Ca0.6La0.8/3TiO3-Li0.5Nd0.5TiO3 (abbreviated CLLNT) ceramics doped by small amounts of ZnO-B2O3-SiO2 glass were investigated in this paper. The adding of ZnO-B2O3-SiO2 glass improved the densifications of the CLLNT ceramics and the sintering temperature of the CLLNT ceramic had been efficiently lowered to 1050°C. Especially, the 8wt% ZnO-B2O3-SiO2 glass doped CLLNT ceramic sintered at 1050°C for 3 h has optimum microwave dielectric properties of Kr=89, Q×f=1445GHz, and TCF=11.4 ppm/°C and it should be a suitable candidate for LTCC applications.

Abstract. BaBi4Ti4O15 powder was synthesized by molten salt synthesis (MSS) method in NaCl-KCl and Na2SO4-K2SO4 fluxes. The phases of reaction products and the microstructures at different calcined temperatures were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). As a result, the flaky BaBi4Ti4O15 powder with anisotropy was synthesized by molten salt synthesis method in NaCl-KCl and Na2SO4-K2SO4 fluxes in the range of 850～1050℃. Compared with BaBi4Ti4O15 powder synthesized in the sulfate flux, the anisotropy level of BaBi4Ti4O15 powder which was synthesized in chloride flux increased, the average particle size(APS) of BaBi4Ti4O15 powder synthesized in the chloride flux is slight larger than in the sulfate flux. The thickness of BaBi4Ti4O15 powder was synthesized by molten salt synthesis method in the chloride flux decreased than in the sulfate.

Mn(1-X)S:AX/ZnS (A: Er, Dy) nanocrystals were synthesized by chemical precipitation method. X-ray diffraction analysis show that Mn(1-X)S:AX/ZnS nanocrystals were zincblende structure. The high-resolution transmission electron microscope images indicated that Mn(1-X)S:AX/ZnS nanocrystals show a spherical shape, and their average grain size is about 4 nm. Photoluminescence spectra of Mn(1-X)S:AX/ZnS nanocrystals revealed that there existed several major emission bands, ～417 nm, ~509 nm, ~580 nm, ~617nm and ~680 nm. Mn(1-X)S:AX/ZnS nanocrystals exhibited enhanced luminescence properties compared with the pure Mn(1-X)S:AX nanocrystals. The enhanced photoluminescence properties of Mn(1-X)S:AX/ZnS nanocrystals should be attributed to the effective suppression of nonradiative recombination by the surface-passivation layer.

Y2O3 nano-phase powders were prepared by polyacrylamide gel method. The mechanism of polyacrylamide gel process and its calcinations procedure were analyzed. The high purity yttria powders can be produced by polyacrylamide gel method at the calcination temperature of 850℃, which is about 100℃ lower than prepared by precipitation method. The microstructure of yttria powders prepared in different proportion of monomer and network agent was investigated. When the mole proportion of monomer and network agent is 5:1, the average size of grains is less than 20nm. Some grains grow abnormally if the proportion deviate from this value and there are a lot agglomerates. Development of such an inexpensive and easy technique for synthesis of high purity yttria nano-phase powders can be of commercial significance.