Aluminum nitride (AlN) ceramic is difficult to sinter through conventional sintering processes. Spark plasma sintering (SPS) was used to sinter it in this study. A pulsed direct current was applied to the AlN powder i...
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Aluminum nitride (AlN) ceramic is difficult to sinter through conventional sintering processes. Spark plasma sintering (SPS) was used to sinter it in this study. A pulsed direct current was applied to the AlN powder in SPS. It engendered concentrated heating in the sinter, and then accelerated the diffusion and contact of AlN particle surfaces. With sintering additive Sm 2O3, the AlN powder was sintered into near-theoretical density in a considerably shorter time cycle compared with conventional sintering processes. The effects of quantity of additive Sm2O 3 and sintering temperature on densification of AlN samples were investigated. Results indicated that the addition of Sm2O3 enhanced the densification of AlN ceramic and lowered the sintering temperature. The AlN ceramics prepared by SPS method had homogeneous crystals. The crystals grains grew well. The Sm-Al-O compounds were created in grain boundary by reaction between Sm2O3 and Al 2O3 on AlN particle surface during the sintering. The reaction effectively accelerated the diffusion among the AlN grains, speeded the densifications of the sinter. And it was favorable to preserve the integrity of the AlN crystal lattice. As a result, the AlN sinter obtained a good thermal conductivity, which was as high as 150W/(m·K).
The title complex [Cu(C12H8N2) · (H2O)2]SO4 was synthesized by hydrothermal method and characterized by elemental analysis, IR and X-ray single crystal structural analysis. The crystal structure indicates that th...
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The title complex [Cu(C12H8N2) · (H2O)2]SO4 was synthesized by hydrothermal method and characterized by elemental analysis, IR and X-ray single crystal structural analysis. The crystal structure indicates that the compound forms a stratiform, built from the SO42- and [Cu(C12H8N2) · (H2O)2]2+ through hydrogen bonds. The chemical formula weight of complex is 375.84. The crystal structure is monoclinic, pace group C2/c with a = 1.485 3(3) nm, b = 1.381 1(3) nm, c = 0.701 0(14) nm, β = 108.650°, V= 1.362 5(15) nm3, Dc = 1.832 g/cm3 ,F(000) = 764, Z = 4,R1 = 0.0290, wR2 = 0.0862. The result of the single crystal X-ray diffraction analysis is in agreement with that of IR measurement, both of them show that the Cu2+ is coordinated by two nitrogen and two oxygen. In addition, the thermostability and IR spectral of the compound were discussed.
Carbon nanotubes（CNTs） decorated with palladium were synthesized and applied to hydrogen storage of gas phase. The results show that the amount of hydrogen storage of the decorated CNTs is up to 3.9%（mass fraction...
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Carbon nanotubes（CNTs） decorated with palladium were synthesized and applied to hydrogen storage of gas phase. The results show that the amount of hydrogen storage of the decorated CNTs is up to 3.9%（mass fraction）, of which, almost 85% H2 can be desorbed at ambient temperature and pressure, while the non-decorated CNTs has a poor performance of hydrogen storage（only about 0.5%H2, mass fraction）. These indicate that it is feasible to enhance the performance of hydrogen storage of CNTs by further decoration with hydrogen-storing metals or alloys.
The transient temperature field analysis aims at the thermal response of LPG vessel under pool fire surrounding environment. The finite element analysis method is used to calculate the temperature field. The thermal b...
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The transient temperature field analysis aims at the thermal response of LPG vessel under pool fire surrounding environment. The finite element analysis method is used to calculate the temperature field. The thermal boundary conditions of LPG vessel are determined according to heat transfer theory and calculated by the software PLGS99. The results show that the maximum temperature gradient of vessel appears near the highest surface where the liquid can reach, and fluctuation of liquid surface is the main reason of high temperature gradient.
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 ...
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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).
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 ...
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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).
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...
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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...
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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 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 ...
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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.
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 ...
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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.
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