Tungsten-doped silver films were prepared by immersing hydrogen-terminated silicon wafers into the solution of 2.5 mmol/L[Ag2WO4]+0.1 mol/L HF at 50℃.Their growth and composition were characterized with atomic force ...Tungsten-doped silver films were prepared by immersing hydrogen-terminated silicon wafers into the solution of 2.5 mmol/L[Ag2WO4]+0.1 mol/L HF at 50℃.Their growth and composition were characterized with atomic force microscopy and X-ray photoelectron spectroscopy,respectively.The effect of tungstate ions on the deposition of silver was investigated by X-ray diffraction(XRD)and scanning electron microscopy(SEM)by comparing W-doped Ag film with Ag film.It is found that the molar fraction of tungsten in the deposits is about 2.3%and the O to W molar ratio was about 4.0 and W-doped Ag films have good anti-corrosion in air at 350℃.The doping of tungsten cannot change the deposition of silver.展开更多
In the batch experiment with W, Ta, Hf, Lu and Mo as radiotracers, a new rapid radiochemical isolation procedure for element tungsten has been developed by using radiochemical separation method and γ spectrum measure...In the batch experiment with W, Ta, Hf, Lu and Mo as radiotracers, a new rapid radiochemical isolation procedure for element tungsten has been developed by using radiochemical separation method and γ spectrum measurement technique.With Voltalef powder carried 2% (W/V)BPHA(Benzoylphenylhydroxylamine)- C5H11OH(iso-amyl-alcohol) organic solution, radioactive W was adsorbed on the Voltalef column in the 4mol/L hydrochloric acid system. Hf, Lu and Mo fractions passed through the Voltalef column rapidly and partial Ta activities retained on the Voltalef column, respectively. Following this, W fraction was eluted completely with 1%Na3C6H5O7(sodium citrate)-5%(W/V) NH4OH solution and no Hf, Lu, Ta and Mo activities passed through the Voltalef extraction chromatographic column. The procedure was simultaneously used to isolate W from Er target bombarded with a low energy 12C beams. By means of this separation system, it is one of the possible way to develop an isolation procedure of Sg, supposing the chemical property of Sg is similar to that of tungsten.展开更多
Enhancing oxidation resistance of multicomponent carbides above 2000℃is critical for their thermal protection applications.For this purpose,novel Nb-and Ta-doped(Hf,Zr,Ti)C multicomponent carbides were designed to im...Enhancing oxidation resistance of multicomponent carbides above 2000℃is critical for their thermal protection applications.For this purpose,novel Nb-and Ta-doped(Hf,Zr,Ti)C multicomponent carbides were designed to improve their oxidation resistance at 2500℃.The results demonstrated that Nb and Ta doping reduced the oxidation rate constant by 16.67%and 25.17%,respectively,thereby significantly improving the oxidation resistance of(Hf,Zr,Ti)C.This enhancement was attributed to the changes in oxycarbide composition and distribution within the oxide layer by adding Nb and Ta.Owing to the different oxidation tendencies of the constituent elements,a distinctive structure was formed in which(Hf,Zr)O_(2)served as a skeleton,and various oxycarbides were dispersed throughout the oxide layer.The doped Nb and Ta were retained within oxycarbides,retarding the diffusion of oxygen into the lattice.More importantly,the addition of Nb and Ta reduced the size of oxycarbides,decreasing both size and quantity of the pores in the oxide layer and facilitating the formation of a more effective oxygen barrier.展开更多
基金Projects(5072106250835009)supported by the National Natural Science Foundation of China
文摘Tungsten-doped silver films were prepared by immersing hydrogen-terminated silicon wafers into the solution of 2.5 mmol/L[Ag2WO4]+0.1 mol/L HF at 50℃.Their growth and composition were characterized with atomic force microscopy and X-ray photoelectron spectroscopy,respectively.The effect of tungstate ions on the deposition of silver was investigated by X-ray diffraction(XRD)and scanning electron microscopy(SEM)by comparing W-doped Ag film with Ag film.It is found that the molar fraction of tungsten in the deposits is about 2.3%and the O to W molar ratio was about 4.0 and W-doped Ag films have good anti-corrosion in air at 350℃.The doping of tungsten cannot change the deposition of silver.
文摘In the batch experiment with W, Ta, Hf, Lu and Mo as radiotracers, a new rapid radiochemical isolation procedure for element tungsten has been developed by using radiochemical separation method and γ spectrum measurement technique.With Voltalef powder carried 2% (W/V)BPHA(Benzoylphenylhydroxylamine)- C5H11OH(iso-amyl-alcohol) organic solution, radioactive W was adsorbed on the Voltalef column in the 4mol/L hydrochloric acid system. Hf, Lu and Mo fractions passed through the Voltalef column rapidly and partial Ta activities retained on the Voltalef column, respectively. Following this, W fraction was eluted completely with 1%Na3C6H5O7(sodium citrate)-5%(W/V) NH4OH solution and no Hf, Lu, Ta and Mo activities passed through the Voltalef extraction chromatographic column. The procedure was simultaneously used to isolate W from Er target bombarded with a low energy 12C beams. By means of this separation system, it is one of the possible way to develop an isolation procedure of Sg, supposing the chemical property of Sg is similar to that of tungsten.
基金This work was supported by the National Natural Science Foundation of China(No.52072410).
文摘Enhancing oxidation resistance of multicomponent carbides above 2000℃is critical for their thermal protection applications.For this purpose,novel Nb-and Ta-doped(Hf,Zr,Ti)C multicomponent carbides were designed to improve their oxidation resistance at 2500℃.The results demonstrated that Nb and Ta doping reduced the oxidation rate constant by 16.67%and 25.17%,respectively,thereby significantly improving the oxidation resistance of(Hf,Zr,Ti)C.This enhancement was attributed to the changes in oxycarbide composition and distribution within the oxide layer by adding Nb and Ta.Owing to the different oxidation tendencies of the constituent elements,a distinctive structure was formed in which(Hf,Zr)O_(2)served as a skeleton,and various oxycarbides were dispersed throughout the oxide layer.The doped Nb and Ta were retained within oxycarbides,retarding the diffusion of oxygen into the lattice.More importantly,the addition of Nb and Ta reduced the size of oxycarbides,decreasing both size and quantity of the pores in the oxide layer and facilitating the formation of a more effective oxygen barrier.
