The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles： ...The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles： micro and nano with sizes of i #m and 5Onto, respectively. The simulation results show that W03 nano particles exhibit a larger increase in linear attenuation coefficient in comparison with micro size particles. Finally, validation of simulation results with the published experimental data shows a good agreement.展开更多
Titanium dioxide （TiO2） loaded tungsten trioxide （WO3） composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-...Titanium dioxide （TiO2） loaded tungsten trioxide （WO3） composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-WO3 composite film shows enhanced photocurrent density, four times than the pure WO3 film illuminated under xenon lamp, and higher incident-photon-to-current conversion e^ciency. By varying the initial TiO2 film thickness, such composite structures could be optimized to obtain the highest photocurrent density. We believe that thin TiO2 films improve the light response and increase the surface roughness of WO3 films. Furthermore, the existence of the heterojunction results in the e^cient charge carriers＇ separation, transfer process, and a lower recombination of electron-hole pairs, which is beneficial for the enhancement of photocurrent density.展开更多
The synergistic antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) of a Cu/WO3-added PTFE (polytetrafluoroethylene) particulate c...The synergistic antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) of a Cu/WO3-added PTFE (polytetrafluoroethylene) particulate composite was reported in the previous paper. The origin of the synergistic antibacterial performance investigated by evaluating the photocatalytic decomposition of the Cu/WO3-added PTFE particulate composite material is reported in the present paper. Addition of Cu/WO3, visible-light-sensitive photocatalyst, to the PTFE particle dispersed superhydrophobic composite does not deteriorate the superhydrophobic property of the composite. Furthermore the existence of the polytetrafluoroethylene (PTFE) particles dispersed in the composite enhances the antibacterial property caused by the Cu/WO3. The authors call this “The synergistic effect”. In this study, a novel synergistic property of the Cu/WO3-added PTFE particulate composite was investigated by evaluating the degradation of gaseous acetaldehyde on the composite surface using visible light (10,000 lx) and UV-A (1 mW·cm-1) illumination. The 12 wt% Cu/WO3-8 wt% binder-80 wt% PTFE composite shows the synergistic visible-light-sensitive photocatalytic property. But 12 wt% Cu/WO3-44 wt% PTFE-44 wt% binder composite no longer shows the synergistic property of visible-light-sensitive photocatalytic property. The synergetic performance of visible-light-sensitive photocatalytic property appears only when PTFE concentration is larger than the critical point over which superhydrophobic property appears in accordance with the particulate composite model derived by the one of the authors. The hydrophobic surface leads to the low surface free energy derived by the revised Fowkes’s theory, which makes it difficult for bacteria to stick to the hydrophobic surface of the composite. Even if bacteria stick to the surface, they are decomposed by the visible-light-sensitive photocatalyst. This is the reason why the synergistic antibacterial performance against bacteria appears.展开更多
Tungsten trioxide micropheres were prepared by spray pyrolysis, and tungsten carbide microspheres were produced by spray pyrolysis-low temperature reduction and carbonization technology. Multi-walled carbon nanotube-t...Tungsten trioxide micropheres were prepared by spray pyrolysis, and tungsten carbide microspheres were produced by spray pyrolysis-low temperature reduction and carbonization technology. Multi-walled carbon nanotube-tungsten carbide composites were prepared by the continuous reduction and carbonization process using multi-walled carbon nanotubes （MWCNTs） and WO3 precursor by mo- lecular level mixing and calcination. The morphology and structure of the samples were characterized by scanning electron microscope and transmission electron microscope. Furthermore, the crystal phase was identified by X-ray diffraction. The electrocatalytic activity of the sample was analyzed by means of me- thanol oxidation. Tungsten carbide microspheres were catalytic active for methanol oxidation reaction. Nevertheless tungsten trioxide microspheres and multi-walled carbon nanotube-tungsten carbide composites were not catalytic active for methanol oxidation reaction. These results indicate that tungsten carbide micropheres are promising catalyst for methanol oxidation.展开更多
A Fe modified Na2WO4 compound was synthesized by a solution impregnation method and was ball-milled with MgH2 to constitute a novel MgH2-Fe2O3/Na2WO4 composite. The effects of the Fe2O3/Na2WO4 additive on the hydrogen...A Fe modified Na2WO4 compound was synthesized by a solution impregnation method and was ball-milled with MgH2 to constitute a novel MgH2-Fe2O3/Na2WO4 composite. The effects of the Fe2O3/Na2WO4 additive on the hydrogen storage properties of MgH2 together with the corresponding mechanism were investigated. At 423 K, within the first 200 seconds, the hydrogen absorption amount of MgH2+20 wt% Fe2O3/Na2WO4 was almost 5 times that of pure MgH2. And at 573 K, its total hydrogen desorption amount was 7 times that for pure MgH2. Meanwhile, its onset dehydrogenation temperature was 110 K lower than that of pure MgH2. It was worth noting that the MgH2+20 wt% Fe/Na2WO4 presented the lower dehydrogenation reaction activation energy(Ea) of 35.9 kJ·mol^-1 compared to that of pure MgH2. The active MgWO4, Mg2 FeH6 and MgO formed during the milling process were responsible for the improvement of the hydrogen storage properties for MgH2.展开更多
文摘The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles： micro and nano with sizes of i #m and 5Onto, respectively. The simulation results show that W03 nano particles exhibit a larger increase in linear attenuation coefficient in comparison with micro size particles. Finally, validation of simulation results with the published experimental data shows a good agreement.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174137,11474215 and 21204058the Natural Science Foundation for the Youth of Jiangsu Province under Grant No BK20130284the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Titanium dioxide （TiO2） loaded tungsten trioxide （WO3） composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-WO3 composite film shows enhanced photocurrent density, four times than the pure WO3 film illuminated under xenon lamp, and higher incident-photon-to-current conversion e^ciency. By varying the initial TiO2 film thickness, such composite structures could be optimized to obtain the highest photocurrent density. We believe that thin TiO2 films improve the light response and increase the surface roughness of WO3 films. Furthermore, the existence of the heterojunction results in the e^cient charge carriers＇ separation, transfer process, and a lower recombination of electron-hole pairs, which is beneficial for the enhancement of photocurrent density.
文摘The synergistic antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) of a Cu/WO3-added PTFE (polytetrafluoroethylene) particulate composite was reported in the previous paper. The origin of the synergistic antibacterial performance investigated by evaluating the photocatalytic decomposition of the Cu/WO3-added PTFE particulate composite material is reported in the present paper. Addition of Cu/WO3, visible-light-sensitive photocatalyst, to the PTFE particle dispersed superhydrophobic composite does not deteriorate the superhydrophobic property of the composite. Furthermore the existence of the polytetrafluoroethylene (PTFE) particles dispersed in the composite enhances the antibacterial property caused by the Cu/WO3. The authors call this “The synergistic effect”. In this study, a novel synergistic property of the Cu/WO3-added PTFE particulate composite was investigated by evaluating the degradation of gaseous acetaldehyde on the composite surface using visible light (10,000 lx) and UV-A (1 mW·cm-1) illumination. The 12 wt% Cu/WO3-8 wt% binder-80 wt% PTFE composite shows the synergistic visible-light-sensitive photocatalytic property. But 12 wt% Cu/WO3-44 wt% PTFE-44 wt% binder composite no longer shows the synergistic property of visible-light-sensitive photocatalytic property. The synergetic performance of visible-light-sensitive photocatalytic property appears only when PTFE concentration is larger than the critical point over which superhydrophobic property appears in accordance with the particulate composite model derived by the one of the authors. The hydrophobic surface leads to the low surface free energy derived by the revised Fowkes’s theory, which makes it difficult for bacteria to stick to the hydrophobic surface of the composite. Even if bacteria stick to the surface, they are decomposed by the visible-light-sensitive photocatalyst. This is the reason why the synergistic antibacterial performance against bacteria appears.
文摘Tungsten trioxide micropheres were prepared by spray pyrolysis, and tungsten carbide microspheres were produced by spray pyrolysis-low temperature reduction and carbonization technology. Multi-walled carbon nanotube-tungsten carbide composites were prepared by the continuous reduction and carbonization process using multi-walled carbon nanotubes （MWCNTs） and WO3 precursor by mo- lecular level mixing and calcination. The morphology and structure of the samples were characterized by scanning electron microscope and transmission electron microscope. Furthermore, the crystal phase was identified by X-ray diffraction. The electrocatalytic activity of the sample was analyzed by means of me- thanol oxidation. Tungsten carbide microspheres were catalytic active for methanol oxidation reaction. Nevertheless tungsten trioxide microspheres and multi-walled carbon nanotube-tungsten carbide composites were not catalytic active for methanol oxidation reaction. These results indicate that tungsten carbide micropheres are promising catalyst for methanol oxidation.
基金Funded by the National Natural Science Foundation of China(No.51771164)Scientific Research Projects in Colleges and Universities in Hebei Province,China(No.ZD2019307)+2 种基金the Fundamental Research Funds for the Central Universities(No.3142019013)the Natural Science Foundation of Hebei Province of China(No.E2019508214)the Program for Top-notch Young Talents in University of Hebei Province(No.BJ2016043)
文摘A Fe modified Na2WO4 compound was synthesized by a solution impregnation method and was ball-milled with MgH2 to constitute a novel MgH2-Fe2O3/Na2WO4 composite. The effects of the Fe2O3/Na2WO4 additive on the hydrogen storage properties of MgH2 together with the corresponding mechanism were investigated. At 423 K, within the first 200 seconds, the hydrogen absorption amount of MgH2+20 wt% Fe2O3/Na2WO4 was almost 5 times that of pure MgH2. And at 573 K, its total hydrogen desorption amount was 7 times that for pure MgH2. Meanwhile, its onset dehydrogenation temperature was 110 K lower than that of pure MgH2. It was worth noting that the MgH2+20 wt% Fe/Na2WO4 presented the lower dehydrogenation reaction activation energy(Ea) of 35.9 kJ·mol^-1 compared to that of pure MgH2. The active MgWO4, Mg2 FeH6 and MgO formed during the milling process were responsible for the improvement of the hydrogen storage properties for MgH2.
