The β-SiC/SiO2 core-shell nanowires with the 'stem-and-node' structure were synthesized in the presence of cerium oxide by the carbothermal reduction of the starch-SiO2 hybrids gel.The samples were characteri...The β-SiC/SiO2 core-shell nanowires with the 'stem-and-node' structure were synthesized in the presence of cerium oxide by the carbothermal reduction of the starch-SiO2 hybrids gel.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM) and energy-dispersed X-ray(EDX).The results showed that the nanowires consisted of a 20-35 nm diameter crystalline β-SiC core wrapped with a 2-5 n...展开更多
In this work, four samples containing different contents of fumed SiO_2 were prepared to improve the pore size distribution and various properties of b nucleated isotatic polypropylene(b-i PP) biaxial membrane used ...In this work, four samples containing different contents of fumed SiO_2 were prepared to improve the pore size distribution and various properties of b nucleated isotatic polypropylene(b-i PP) biaxial membrane used for lithium-ion battery separator. The wide-angle X-ray diffraction(WAXD) and differential scanning calorimetry(DSC) results show that the fumed SiO_2 promotes the formation of b-crystal slightly and narrows down the thickness distribution of b-lamellae; meanwhile, evenly distributed SiO_2 within b-i PP can be inspected by scanning electron microscopy(SEM). Moreover, further detailed characterization of morphological evolutions during biaxial stretching by tensile testing and SEM manifests that SiO_2 can strengthen b-i PP and make the samples deform more homogeneously, resulting in a gradually elaborate and finer oriented microfibril structure after longitudinal stretching, in which more uniform defects distribute between fibrils and restrain the formation of coarse fibrils effectively. Therefore, more superior microporous structure emerges with the addition of SiO_2, accompanied by narrower pore size distribution and better connectivity between microvoids, which is confirmed by mercury porosimeter and diminished Gurley value. Moreover, the lower thermal shrinkage, decreased shrinkage rate and suppressed porosity reduction indicate that fumed SiO_2 improves thermal and dimensional stability of membrane dramatically. Furthermore, due to the excellent wettability of SiO_2 with electrolyte, the microporous membranes doped with SiO_2 have higher electrolyte uptake, even after heat treatment at elevated temperature.展开更多
A series of molybdenum carbides were synthesized using the non-routine carbon source C_ 3 H_ 8 with oxide and nitride as precursors and characterized by XRD, SEM and elemental analysis. The catalytic activity measurem...A series of molybdenum carbides were synthesized using the non-routine carbon source C_ 3 H_ 8 with oxide and nitride as precursors and characterized by XRD, SEM and elemental analysis. The catalytic activity measurements of the as-prepared bulk and amorphous SiO_ 2 supported catalysts for thiophene HDS were carried out in a pulse microreactor-gas chromatography and their apparent activation energy was calculated. β-Mo_ 2 C was proved to be the most active phase, the Ea value of which was reduced by being supported on SiO_ 2 .展开更多
基金supported by the National Key Technology R&D Program (2007BEA08B01)the Natural Science Foundation of Fujian Province of China (E0710004)Joint Research Program of Fuzhou University (DH-548)
摘要The β-SiC/SiO2 core-shell nanowires with the 'stem-and-node' structure were synthesized in the presence of cerium oxide by the carbothermal reduction of the starch-SiO2 hybrids gel.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM) and energy-dispersed X-ray(EDX).The results showed that the nanowires consisted of a 20-35 nm diameter crystalline β-SiC core wrapped with a 2-5 n...
基金financially supported by the National Natural Science Foundation of China (No. 51421061)
摘要In this work, four samples containing different contents of fumed SiO_2 were prepared to improve the pore size distribution and various properties of b nucleated isotatic polypropylene(b-i PP) biaxial membrane used for lithium-ion battery separator. The wide-angle X-ray diffraction(WAXD) and differential scanning calorimetry(DSC) results show that the fumed SiO_2 promotes the formation of b-crystal slightly and narrows down the thickness distribution of b-lamellae; meanwhile, evenly distributed SiO_2 within b-i PP can be inspected by scanning electron microscopy(SEM). Moreover, further detailed characterization of morphological evolutions during biaxial stretching by tensile testing and SEM manifests that SiO_2 can strengthen b-i PP and make the samples deform more homogeneously, resulting in a gradually elaborate and finer oriented microfibril structure after longitudinal stretching, in which more uniform defects distribute between fibrils and restrain the formation of coarse fibrils effectively. Therefore, more superior microporous structure emerges with the addition of SiO_2, accompanied by narrower pore size distribution and better connectivity between microvoids, which is confirmed by mercury porosimeter and diminished Gurley value. Moreover, the lower thermal shrinkage, decreased shrinkage rate and suppressed porosity reduction indicate that fumed SiO_2 improves thermal and dimensional stability of membrane dramatically. Furthermore, due to the excellent wettability of SiO_2 with electrolyte, the microporous membranes doped with SiO_2 have higher electrolyte uptake, even after heat treatment at elevated temperature.
摘要A series of molybdenum carbides were synthesized using the non-routine carbon source C_ 3 H_ 8 with oxide and nitride as precursors and characterized by XRD, SEM and elemental analysis. The catalytic activity measurements of the as-prepared bulk and amorphous SiO_ 2 supported catalysts for thiophene HDS were carried out in a pulse microreactor-gas chromatography and their apparent activation energy was calculated. β-Mo_ 2 C was proved to be the most active phase, the Ea value of which was reduced by being supported on SiO_ 2 .