The properties of La 2O 3 doped molybdenum powder were studied. The La 2O 3 nanoparticles on the surface of molybdenum powder which is produced by the reduction of La(NO 3) 3 doped MoO 2 in hydrogen decrease the inten...The properties of La 2O 3 doped molybdenum powder were studied. The La 2O 3 nanoparticles on the surface of molybdenum powder which is produced by the reduction of La(NO 3) 3 doped MoO 2 in hydrogen decrease the intensity of feature energy loss peak of molybdenum substrate; but increase that of peak of Mo?3d. The surface of molybdenum powder exposed to the atmosphere can be reduced because the surface is mainly covered with La 2O 3 nanoparticles. As a result, the capability of anti oxidation of molybdenum is improved.展开更多
The control synthesis of nanoparticles was the implementation process of material ideal design. Nano-hydroxyapatite(HAP) was prepared by a hydrothermal method with calcium nitrate and diammonium hydrogen phosphate as ...The control synthesis of nanoparticles was the implementation process of material ideal design. Nano-hydroxyapatite(HAP) was prepared by a hydrothermal method with calcium nitrate and diammonium hydrogen phosphate as raw material, to study its characteristics for morphology modification by arginine-functionalization and doping with rare earth such as Tb^(3+). The crystallization, grain size and dispersibility of the sample HAP were analyzed and discussed. The results show that the surface Zeta potential of arginine-functionalized HAP is changed, and the growth rate of HAP is inhibited to a certain extent during the synthesis. The structure of HAP/Arg is not affected during the synthesis by a small amount of rare earth ions doped such as Tb^(3+), and has a single phase of HAP with good dispersibility. The synthesized HAP is also of nano-sized level. Nano-hydroxyapatite argininefunctionalized and doped with rare earth such as Tb^(3+), is suitable for the application of gene delivery as a gene carrier.展开更多
In this study, the Yb（1-x）CaxFeO3（0≤x≤0.3） nanocrystalline powders were prepared by sol-gel method. We used the method of quantitative analysis to research the gas-sensitive properties for Yb（1-x）CaxFeO3 to CO...In this study, the Yb（1-x）CaxFeO3（0≤x≤0.3） nanocrystalline powders were prepared by sol-gel method. We used the method of quantitative analysis to research the gas-sensitive properties for Yb（1-x）CaxFeO3 to CO2. Also, we investigated the effects of various factors on gas sensing properties by simple variable method. The doping of Ca could not only decrease the resistance of YbFeO3, but also enhance its sensitivity to CO2. When the Ca content x=0.2, Yb（1-x）CaxFeO3 showed the best response to CO2. The response Rg/Ra to 5000 ppm CO2 for Yb（0.8）Ca（0.2）FeO3 at its optimal temperature of 260 °C with the room temperature humidity of 28%RH was 1.85. The response and recovery time decreased with an increase of the operating temperature for Yb（0.8）Ca（0.2）FeO3 sensor to 5000 ppm CO2. Furthermore, with an increase of CO2 concentration from 1000 to 50000 ppm, the response time of Yb（0.8）Ca（0.2）FeO3 became shorter, and meanwhile the recovery time was longer. CO2-sensing response for Yb（0.8）Ca（0.2）FeO3 increased with the increase of relative humidity. The response for Yb（0.8）Ca（0.2）FeO3 in the background of air（with the room temperature humidity of 39%RH） at 260 °C could reach 2.012 to 5000 ppm CO2, which was larger than the corresponding value（1.16） in dry air.展开更多
文摘The properties of La 2O 3 doped molybdenum powder were studied. The La 2O 3 nanoparticles on the surface of molybdenum powder which is produced by the reduction of La(NO 3) 3 doped MoO 2 in hydrogen decrease the intensity of feature energy loss peak of molybdenum substrate; but increase that of peak of Mo?3d. The surface of molybdenum powder exposed to the atmosphere can be reduced because the surface is mainly covered with La 2O 3 nanoparticles. As a result, the capability of anti oxidation of molybdenum is improved.
基金Project(2013SK2024)supported by the Key Projects in Social Development Pillar Program of Hunan Province,ChinaProject(20130162120094)supported by Specialized Research Fund for the Doctoral Program of Higher Education(SRFDP),Ministry of Education,ChinaProject supported by State Key Laboratory of Powder Metallurgy,Central South University,China
文摘The control synthesis of nanoparticles was the implementation process of material ideal design. Nano-hydroxyapatite(HAP) was prepared by a hydrothermal method with calcium nitrate and diammonium hydrogen phosphate as raw material, to study its characteristics for morphology modification by arginine-functionalization and doping with rare earth such as Tb^(3+). The crystallization, grain size and dispersibility of the sample HAP were analyzed and discussed. The results show that the surface Zeta potential of arginine-functionalized HAP is changed, and the growth rate of HAP is inhibited to a certain extent during the synthesis. The structure of HAP/Arg is not affected during the synthesis by a small amount of rare earth ions doped such as Tb^(3+), and has a single phase of HAP with good dispersibility. The synthesized HAP is also of nano-sized level. Nano-hydroxyapatite argininefunctionalized and doped with rare earth such as Tb^(3+), is suitable for the application of gene delivery as a gene carrier.
基金Project supported by the National Natural Science Foundation of China(51272133,51472145,51472150)
文摘In this study, the Yb（1-x）CaxFeO3（0≤x≤0.3） nanocrystalline powders were prepared by sol-gel method. We used the method of quantitative analysis to research the gas-sensitive properties for Yb（1-x）CaxFeO3 to CO2. Also, we investigated the effects of various factors on gas sensing properties by simple variable method. The doping of Ca could not only decrease the resistance of YbFeO3, but also enhance its sensitivity to CO2. When the Ca content x=0.2, Yb（1-x）CaxFeO3 showed the best response to CO2. The response Rg/Ra to 5000 ppm CO2 for Yb（0.8）Ca（0.2）FeO3 at its optimal temperature of 260 °C with the room temperature humidity of 28%RH was 1.85. The response and recovery time decreased with an increase of the operating temperature for Yb（0.8）Ca（0.2）FeO3 sensor to 5000 ppm CO2. Furthermore, with an increase of CO2 concentration from 1000 to 50000 ppm, the response time of Yb（0.8）Ca（0.2）FeO3 became shorter, and meanwhile the recovery time was longer. CO2-sensing response for Yb（0.8）Ca（0.2）FeO3 increased with the increase of relative humidity. The response for Yb（0.8）Ca（0.2）FeO3 in the background of air（with the room temperature humidity of 39%RH） at 260 °C could reach 2.012 to 5000 ppm CO2, which was larger than the corresponding value（1.16） in dry air.
