A new niobate compound with the chemical composition of Ba5LiTiNb9O30 was synthesized by doping Li+ into the system BaO-TiO2-Nb2O5 in conventional solid state reaction method. The crystalline structure was determined ...
详细信息
A new niobate compound with the chemical composition of Ba5LiTiNb9O30 was synthesized by doping Li+ into the system BaO-TiO2-Nb2O5 in conventional solid state reaction method. The crystalline structure was determined by X-ray diffraction analysis (XRD). The results showed that crystal structure of Ba5LiTiNb9O30 belongs to tetrago-nal tungsten bronze structure with space group P4bm and its unit cell parameters: a=b=1.2512(2) nm, c=0.4008(5) nm. The microstructure of reaction products was observed by scanning electron microscopy (SEM).
By means of chemical reduction,nanoparticles of platinum were deposited on the surface of multi walled carbon nanotubes (MWCNTs).The performance of hydrogen storage of as prepared MWCNTs decorated with platinum was ...
详细信息
By means of chemical reduction,nanoparticles of platinum were deposited on the surface of multi walled carbon nanotubes (MWCNTs).The performance of hydrogen storage of as prepared MWCNTs decorated with platinum was *** results indicate that:(1) Hydrogen uptake is more quick and intense for decorated MWCNTs than that for not decorated ones at 10.931MPa and room *** saturation of hydrogen uptake of the former only lasts about 30min,while the latter needs about 150 min;(2) The amount of hydrogen uptake of decorated MWCNTs is about 1.13wt%, which is larger than that of not decorated ones(about 0.54wt%);(3) However,more than 37% hydrogen absorbed by decorated MWCNTs is chemisorbed.
Electrical conductivity and seebeck coefficient at different temperatures,and thermal conductivity at room temperature for various doped polyaniline (PAn) samples were measured,and the thermoelectric figure of merit Z...
详细信息
Electrical conductivity and seebeck coefficient at different temperatures,and thermal conductivity at room temperature for various doped polyaniline (PAn) samples were measured,and the thermoelectric figure of merit ZT was *** effects of preparation methods and temperature on thermoelectric properties were *** results show that the electrical conductivity and the seebeck coefficient of PAn are strongly dependent on the preparation conditions and *** electrical conductivity becomes larger and the seebeck coefficient becomes smaller as PAn molecular weight *** by organic acid and HCl results in an increase in both electrical conductivity and Seebeck coefficient of PAn,and therefore ZT *** electrical conductivity increases and the seebeck coefficient decreases as the temperature increases when TT *** thermal conductivity is lower,and insensitive to the sample preparation conditions.
The objective of this paper is to understand the flow mechanism through visualization experiments and discuss theinfluence of process parameters on mold filling process. A 2D leakage flow model is developed to simulat...
详细信息
The objective of this paper is to understand the flow mechanism through visualization experiments and discuss theinfluence of process parameters on mold filling process. A 2D leakage flow model is developed to simulate the moldingprocess, and the simulation results show good agreement with experiments.
The visualization experiments were carried out to investigate the permeability of the high permeable medium (HPM) and the roles of the peel ply and the HPM in the mold *** influence of process parameters on mold fill...
详细信息
The visualization experiments were carried out to investigate the permeability of the high permeable medium (HPM) and the roles of the peel ply and the HPM in the mold *** influence of process parameters on mold filling is ***,the whole vacuum infusion molding process (VIMP) procedure is introduced in detail taking the manufacture of a model boat for example.
The homogeneous glass samples of the (1-x)As 2S 3 xCdCl 2 where x=0 and 0.05 were prepared by the conventional melt quenched *** addition of 5mol% CdCl 2 enhanced the glass transition temperature of pure As 2S ...
详细信息
The homogeneous glass samples of the (1-x)As 2S 3 xCdCl 2 where x=0 and 0.05 were prepared by the conventional melt quenched *** addition of 5mol% CdCl 2 enhanced the glass transition temperature of pure As 2S 3 glass sample by about 30℃.Based on the experimental data,the microstructure is considered to be that the discrete molecule species of AsCl 3 and nanocrystal CdS is homogeneously dispersed in the disordered polymer network formed by AsS 3 pyramids interconnected by sulfur bridges.
A novel and efficient methodology for obtaining highly active photocatalyst of bi phase TiO 2 with small particle size and high specific surface area was developed by solvent evaporation induced crystallization (SE...
详细信息
A novel and efficient methodology for obtaining highly active photocatalyst of bi phase TiO 2 with small particle size and high specific surface area was developed by solvent evaporation induced crystallization (SEIC) method at low temperature. The prepared TiO 2 powder was characterized with X ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface areas. The photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. The results showed that the photocatalytic activity of the TiO 2 powder prepared by this method approached that of Degussa P25. This may be attributed to the fact that the prepared TiO 2 powder had larger specific surface areas (265 m 2·g -1 ) and smaller crystallite size (about 5 nm), but relatively low crystallinity, as compared with Degussa P25.
Highly photoactive bi-phase nanocrystalline TiO2 photocatalyst was prepared by a solvent evaporation-induced crystallization (SEIC) method, and calcined at different temperatures. The obtained TiO2 photocatalyst was c...
详细信息
Highly photoactive bi-phase nanocrystalline TiO2 photocatalyst was prepared by a solvent evaporation-induced crystallization (SEIC) method, and calcined at different temperatures. The obtained TiO2 photocatalyst was characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface areas. The photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. The results show that solvent evaporation can promote the crystallization and phase transformation of TiO2 at 100°C. When calcination temperatures are below 600°C, the prepared TiO2 powders show bimodal pore size distributions in the mesoporous region. At 700°C, the pore size distributions exhibit monomodal distribution of the inter-aggregated pores due to the collapse of the intra-aggregated pores. At 100°C, the obtained TiO2 photocatalyst by this method shows good photocatalytic activity, and at 400°C, its photocatalytic activity exceeds that of Degussa P25. This may be attributed to the fact that the prepared TiO2 photocatalyst has higher specific surface areas, smaller crystallite size and bimodal pore size distribution.
Ti 3SiC 2 materials have been fabricated by spark plasma sintering of the elemental powders with the addition of Al. At the heating rate of 80 ℃/min and under the pressure of 30 MPa, the ideal synthesis temperature o...
详细信息
Ti 3SiC 2 materials have been fabricated by spark plasma sintering of the elemental powders with the addition of Al. At the heating rate of 80 ℃/min and under the pressure of 30 MPa, the ideal synthesis temperature of Ti 3SiC 2 is in the range of 1 1501 250 ℃. The addition of Al is in favor of the formation of Ti 3SiC 2. The synthesized compound has the molecular of Ti 3Si 0.8Al 0.2C 2 and lattice parameters of a=0.306 9 nm, c=1.767 0 nm. Its grain is plane-shape with a size of about 50 μm in the elongated dimension. The prepared material has Vickers hardness of 3.55.5 GPa(at 1 N and 15 s) and is as readily machinable as graphite’s.
CoSb/sub 3/ micrometer powder was synthesized by solid-state reaction using high purity powder of Co, Sb as the starting materials. CoSb/sub 3/ nano-powder and block material with nanostructure were prepared by high-e...
详细信息
CoSb/sub 3/ micrometer powder was synthesized by solid-state reaction using high purity powder of Co, Sb as the starting materials. CoSb/sub 3/ nano-powder and block material with nanostructure were prepared by high-energy ball-milling and by Spark Plasma Sintering (SPS), respectively. The influence of mass ratio of big balls and small balls, milling speed and time on particles size of CoSb/sub 3/ powder, and sintering temperature and time on grains size of CoSb/sub 3/ were investigated. The influence of nanostructure on thermal transport properties of CoSb/sub 3/ was also studied.
暂无评论