The process of use catalyst or functional material that contains iron ion to weaken -O-H-O- hydrogen bond of the thick oil to reduce viscidity or crack, in aspects of the ion charge. covalent bond order, total energy ...
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The process of use catalyst or functional material that contains iron ion to weaken -O-H-O- hydrogen bond of the thick oil to reduce viscidity or crack, in aspects of the ion charge. covalent bond order, total energy and the average distance of Fe-O. is studied with density function theory and discrete variational method （DFT-DVM）, one of the first principle methods. With the decrease of the distance of Fe-O. the charge of Fe ion increases, the charge of hydrogen ion decreases, and hydrogen bond is weakened. There are obvious and more stable effects to use the catalyst that contains multiple metal ions or increase the catalyst amount in weakening hydrogen bond of the thick oil. This theoretic work is helpful to exploit and process the thick oil of petroleum and maybe overcome the crisis of petroleum energy is approaching to us.
The coprecipitation precursors with nominal composition of xFe+BaFe12O19(0≤x≤1, Δx=0.2) were prepared by chemical coprecipitation process. The crystallization behavior of the precursor under the spark plasma sinter...
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The coprecipitation precursors with nominal composition of xFe+BaFe12O19(0≤x≤1, Δx=0.2) were prepared by chemical coprecipitation process. The crystallization behavior of the precursor under the spark plasma sintering (SPS) conditions and the magnetic properties of the SPS samples were investigated. The results show that the crystallization of intermediate such as Fe2O3did not occur in all the SPS samples. The SPS samples for 03O4and Ba2Fe14O22(Fe2Y) and for 0.8≤x≤1.0 were composed of Fe3O4and Fe2Y, though the SPS sample for x=0 was composed of single-phase BaM. BaM gradually reduced and Fe3O4and Fe2Y gradually increased as the x increased. Needle Fe2Y mainly occurred in the interface area between Fe3O4and BaM. However, Fe2Y and Fe3O4are randomly distributed in these samples without BaM. The saturation magnetization first reduced significantly and remained almost constant, finally remarkably decreased again and then slightly increased. This accorded with the evolution characteristics of the phase composition of the SPS samples with the increase of x. The coercivity first increased significantly and then decreased slightly with the increase of x, which was attributed to the corresponding increases in the content of Fe3O4and Fe2Y, the reduction in the content of BaM, and the growth of Fe3O4and Fe2Y.
Mg2Si1-xSnx (0&lex&le1) Solid Solutions have been fabricated by the low-temperature solid state reaction and spark plasma sintering, and the influence of tin concentration on thermoelectric properties was inve...
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Mg2Si1-xSnx (0&lex&le1) Solid Solutions have been fabricated by the low-temperature solid state reaction and spark plasma sintering, and the influence of tin concentration on thermoelectric properties was investigated. Results indicated that the thermoelectric properties of Mg2Si1-xSnx are sensitive to tin concentration. With the increases of tin content, the electrical conductivity increases while the absolute value of Seebeck coefficient decreases, and the lattice thermal conductivity first decreases, reaching a minimum value when x=0.4, then increases with tin content further increases. The lattice thermal conductivity of Mg2Si1-xSnx solid solution is considerably lower than the binary Mg2Si and Mg2Sn alloy, which is about one third and one half the value at room temperature for Mg2Si and Mg2Sn alloy, respectively. The highest dimensionless figure of merit reaches 0.16 at 640 K for sample x=0.2.
5083 aluminum Alloy was prepared by cryomilling method. The microstructure, microstructural evolution and thermal stability and of sample powder were investigated by XRD, SEM and DSC. The results showed that the parti...
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5083 aluminum Alloy was prepared by cryomilling method. The microstructure, microstructural evolution and thermal stability and of sample powder were investigated by XRD, SEM and DSC. The results showed that the particles size of 5083 alloy powder during cryomilling was gradually reduced, Mg phase was gradually disappeared and super-saturated to Al;Milling time and milling speed were the main factors of affected alloy structure and performance, and high speed cryomilling could result in more uniform nanometer grains. Energy spectrum analysis and DSC suggest that the thermal stability of the cryomilling 5083 alloy powder was improved at certain extent, it may be attributed to the presence of nano-scale Al2O3 particles.
Boron carbide ceramics were synthesized and desificated in one step by spark plasma sintering (SPS) technique using boron and graphite powders as raw materials. The impact of sintering temperature, sintering pressure,...
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Boron carbide ceramics were synthesized and desificated in one step by spark plasma sintering (SPS) technique using boron and graphite powders as raw materials. The impact of sintering temperature, sintering pressure, holding time and heating program, on sintering performance of boron carbide ceramics was studied. The results indicated that the starting temperature of synthesis was at 1100°C;higher temperature and pressure, appropriate holding time and heating-up rate, as well as two holding steps were beneficial to densification of boron carbide ceramics. The suitable SPS process conditions were optimized as: sintering temperature of 1800°C, pressure of 40 MPa, holding time of 6 min, heating-up rate of 100°C/min, and two holding steps, on which boron carbide ceramics of higher density were obtained.
Using boron carbide (B4C), zirconium oxide (ZrO2) and graphite (C) as starting materials, ZrB2-B4C composites were prepared by Spark Plasma Sintering-Reaction synthesis. The reaction process was studied by theoretical...
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Using boron carbide (B4C), zirconium oxide (ZrO2) and graphite (C) as starting materials, ZrB2-B4C composites were prepared by Spark Plasma Sintering-Reaction synthesis. The reaction process was studied by theoretical calculation, DSC and XRD of the specimens sintered at different temperatures. And the sintering mechanism was analyzed through the shrinkage ratio curve during the sintering. The results showed that the start temperature of the reaction among ZrO2, B4C and C accords with the theoretical temperature. At the initial stage of the sintering of ZrB2-B4C, the kinetic equation of the shrinkage showed that the sintering mechanism was a surface melting sintering mechanism.
The precursors of CIS and CIGS thin films were prepared by one-step electrodeposition in alcohol solution and then annealed in Ar atmosphere at 550°C for 30min. The influences of deposition potentials and salt co...
Hierarchically organized γ-AlOOH hollow spheres with nanoflake-like porous surface textures were fabricated by chemically induced self-transformation of metastable solid particles of amorphous aluminium oxyhydroxide ...
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Hierarchically organized γ-AlOOH hollow spheres with nanoflake-like porous surface textures were fabricated by chemically induced self-transformation of metastable solid particles of amorphous aluminium oxyhydroxide produced in situ within hydrothermal reaction mixtures containing aluminium sulfate and urea. Thermal treatment of the γ-AlOOH product at 600 °C produced intact hollow spheres of γ-Al 2 O 3 . Formation of the hollow γ-AlOOH structures was strongly dependent on the reaction temperature and time, as well as the concentration and molar ratio of the reactants. Hollow γ-AlOOH spheres were not obtained using mixtures of urea and aluminium nitrate or aluminium chloride, as metastable precursor particles were not produced under these conditions. In general, the described method is efficient and environmentally benign, and has significant advantages over traditional template approaches to the large-scale production of hollow inorganic materials. The prepared hierarchically organized γ-AlOOH and γ-Al 2 O 3 hollow spheres should have important applications in areas of catalysis, separation science, biomedical engineering and nanotechnology.
High temperature dielectric properties were studied in La and Nb co-doped Sr2Ta2O7system. The resistivity activation energy increases by La-doping leading to increase of resistivity. The resistivity of Sr1.98La0.02Ta2...
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High temperature dielectric properties were studied in La and Nb co-doped Sr2Ta2O7system. The resistivity activation energy increases by La-doping leading to increase of resistivity. The resistivity of Sr1.98La0.02Ta2O7is 3.65 × 107at 700°C, significantly higher when compared to the resistivity of Sr2Ta2O7(4.37 × 106)at same temperature. The Nb-doping has little influence on the structure of Sr2Ta2O7except displacements of the O ions perpendicular to the line joining the Ta and O ions. The Curie temperature was improved greatly by Nb-doping, which increase from -173°C (Sr2Ta2O7) to -11°C (Sr1.98La0.02Ta1.9Nb0.1O7).
Raw Mg,Si powder were used to fabricate Mg2Si bulk thermoelectric generator by spark plasma sintering （SPS）.The optimum parameters to synthesize pure Mg2Si powder were found to be 823 K,0 MPa,10 min with excessive c...
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Raw Mg,Si powder were used to fabricate Mg2Si bulk thermoelectric generator by spark plasma sintering （SPS）.The optimum parameters to synthesize pure Mg2Si powder were found to be 823 K,0 MPa,10 min with excessive content of 10wt% Mg from the stoichiometric ***2Si bulk was synthesized and densified simultaneously at low temperature （823 K） and high pressure （higher than 100 MPa） from the raw powder,but Mg,Si could not react completely,and the sample was not very dense with some microcracks on the ***,Mg,Si powder reacted at 823 K,0 MPa,10 min in SPS chamber to form Mg2Si green compact,again sintered by SPS at 1023 K,20 MPa,5 *** fabricated sample only contained Mg2Si phase with fully relative density.
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