Annealing study of the Al/GaSb system was performed by using a slow positron beam and the measurement of X-ray diffraction. The S parameter against positron energy data were fitted by a three layer model （Al/interfac...Annealing study of the Al/GaSb system was performed by using a slow positron beam and the measurement of X-ray diffraction. The S parameter against positron energy data were fitted by a three layer model （Al/interface/GaSb）. It was found there was a ～5 nm interfacial at the region between the Al layer and bulk in the sample of as-deposited. After the 400 ℃ annealing, this interfacial region extends to over 40 nm and S parameter dramatically drops. This is possibly due to a new phase formation induced by the atoms＇inter-diffusion at the interface. The annealing out of the open volume defects in the Al layer was revealed by the decrease of the S parameter and the increase of the effective diffusion length of the Al layer. Annealing behaviors of Sb and Lb of the GaSb bulk showed the annealing out of positron traps at 250 ℃. However,further annealing at 400 ℃ induces formation of positron traps, which are possibly another kind of VGarelated defect and the positron shallow trap GaSb anti-site. The results of the X-ray diffraction experiment verified the conclusion of obtained by using positron technology.展开更多
Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 （Si/AI ratio 22） sorbent material was investigated. MCM-68 was synthesized using N,N,N＇,N＇-...Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 （Si/AI ratio 22） sorbent material was investigated. MCM-68 was synthesized using N,N,N＇,N＇-tetraethylbicyclo [2.2.2] oct-7-ene-2,3：5,6-dipyrrolidinium diiodide （TEBOP^2＋（I^＋）2） as a structure-directing agent （SDA）. CO2 adsorption capacity on MCM-68 sorbent was measured at a broad temperature window i.e. 60 ℃, 300 ℃ and at 400 ℃. The presence of ordered mesoporous structure, high surface area （456 me/g） and high thermal stability （TGA analysis up to 900℃） in MCM-68 are thought to be to be advantageous for the CO2 adsorption in broad temperature window.展开更多
To prevent CO_2 accumulation in the atmosphere generated from scorching of fossil fuels, carbon capture and sequestration(CCS) technology is considered as a potential route to mitigate the emissions of CO_2 from reach...To prevent CO_2 accumulation in the atmosphere generated from scorching of fossil fuels, carbon capture and sequestration(CCS) technology is considered as a potential route to mitigate the emissions of CO_2 from reaching the atmosphere. Power generation from sources such as gas, coal and biomass can fulfill the energy demand more readily than many other sources of electricity production. Thus these sources may be retained as important alternative option in the global energy cycle. In order to curtail CO_2, porous aramid network was fabricated by the condensation of 1,3,5-benzenetricarbonyl trichloride and 1,3-phenylenediamine in 1,4-dioxane solvent. Aramid was characterized for various analyses including FTIR, XRD, TGA, BET surface area and pore size analysis, FESEM and CO_2 adsorption measurements. Excellent thermal stability was provided by strong amide linkages in the polymer backbone. Optimum CO_2 uptake of aramid was achieved to be 23.14 mg·g^(-1) at 273 K at 0.1 MPa. The basic amide groups of network structure showed greater affinity for CO_2.Excellent thermal stability of aramid makes it a promising sorbent for CO_2 capture in adverse conditions.展开更多
Ag nanoparticles were fabricated on Si substrates by radio-frequency magnetron sputtering and thermal annealing treatments.It was found that Ag nanoparticles are ellipsoid at low annealing temperature,but the axis rat...Ag nanoparticles were fabricated on Si substrates by radio-frequency magnetron sputtering and thermal annealing treatments.It was found that Ag nanoparticles are ellipsoid at low annealing temperature,but the axis ratio decreases with the increase of annealing temperature,and a shape transformation from ellipsoid to sphere occurs when the temperature increases to a critical point.The experimental results showed that the surface plasmon resonances depend greatly on the nanoparticles'shape and size,which is in accordance with the theoretical calculation based on discrete dipole approximation.The results of forward-scattering efficiency(FSE) and light trapping spectrum(LTS) showed that Ag nanoparticles annealed at 400°C could strongly enhance the light harvest than those annealed at 300 and 500°C,and that the LTS peak intensity of the former is 1.7 and 1.5 times stronger than those of the later two samples,respectively.The conclusions obtained in this paper showed that Ag ellipsoid nanoparticles with appropriate size is more favorable for enhancing the light trapping.展开更多
基金Supported by the National Natural Science Foundation of China(10375081,10473007,10771140)Shanghai Municipal Education Commission(06DZ111)Shanghai Normal University(PL609)
基金This work was supported by the CERG, RGC, HKSAR （projects 7134/99P and 7107/02P）the National Science Foundation of China （No.10425072）.
文摘Annealing study of the Al/GaSb system was performed by using a slow positron beam and the measurement of X-ray diffraction. The S parameter against positron energy data were fitted by a three layer model （Al/interface/GaSb）. It was found there was a ～5 nm interfacial at the region between the Al layer and bulk in the sample of as-deposited. After the 400 ℃ annealing, this interfacial region extends to over 40 nm and S parameter dramatically drops. This is possibly due to a new phase formation induced by the atoms＇inter-diffusion at the interface. The annealing out of the open volume defects in the Al layer was revealed by the decrease of the S parameter and the increase of the effective diffusion length of the Al layer. Annealing behaviors of Sb and Lb of the GaSb bulk showed the annealing out of positron traps at 250 ℃. However,further annealing at 400 ℃ induces formation of positron traps, which are possibly another kind of VGarelated defect and the positron shallow trap GaSb anti-site. The results of the X-ray diffraction experiment verified the conclusion of obtained by using positron technology.
文摘Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 （Si/AI ratio 22） sorbent material was investigated. MCM-68 was synthesized using N,N,N＇,N＇-tetraethylbicyclo [2.2.2] oct-7-ene-2,3：5,6-dipyrrolidinium diiodide （TEBOP^2＋（I^＋）2） as a structure-directing agent （SDA）. CO2 adsorption capacity on MCM-68 sorbent was measured at a broad temperature window i.e. 60 ℃, 300 ℃ and at 400 ℃. The presence of ordered mesoporous structure, high surface area （456 me/g） and high thermal stability （TGA analysis up to 900℃） in MCM-68 are thought to be to be advantageous for the CO2 adsorption in broad temperature window.
文摘To prevent CO_2 accumulation in the atmosphere generated from scorching of fossil fuels, carbon capture and sequestration(CCS) technology is considered as a potential route to mitigate the emissions of CO_2 from reaching the atmosphere. Power generation from sources such as gas, coal and biomass can fulfill the energy demand more readily than many other sources of electricity production. Thus these sources may be retained as important alternative option in the global energy cycle. In order to curtail CO_2, porous aramid network was fabricated by the condensation of 1,3,5-benzenetricarbonyl trichloride and 1,3-phenylenediamine in 1,4-dioxane solvent. Aramid was characterized for various analyses including FTIR, XRD, TGA, BET surface area and pore size analysis, FESEM and CO_2 adsorption measurements. Excellent thermal stability was provided by strong amide linkages in the polymer backbone. Optimum CO_2 uptake of aramid was achieved to be 23.14 mg·g^(-1) at 273 K at 0.1 MPa. The basic amide groups of network structure showed greater affinity for CO_2.Excellent thermal stability of aramid makes it a promising sorbent for CO_2 capture in adverse conditions.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61006050 and 51072051)the Natural Science Foundation of Beijing,China (Grant No. 2102042)+2 种基金the Fundamental Research Funds for the Central Universities (Grant No. 10QG24)the National High Technology Research and Development Program ("863" Project)(Grant No. 2011AA050507)the National Basic Research Program of China("973" Project)(Grant No. 2010CB93380)
文摘Ag nanoparticles were fabricated on Si substrates by radio-frequency magnetron sputtering and thermal annealing treatments.It was found that Ag nanoparticles are ellipsoid at low annealing temperature,but the axis ratio decreases with the increase of annealing temperature,and a shape transformation from ellipsoid to sphere occurs when the temperature increases to a critical point.The experimental results showed that the surface plasmon resonances depend greatly on the nanoparticles'shape and size,which is in accordance with the theoretical calculation based on discrete dipole approximation.The results of forward-scattering efficiency(FSE) and light trapping spectrum(LTS) showed that Ag nanoparticles annealed at 400°C could strongly enhance the light harvest than those annealed at 300 and 500°C,and that the LTS peak intensity of the former is 1.7 and 1.5 times stronger than those of the later two samples,respectively.The conclusions obtained in this paper showed that Ag ellipsoid nanoparticles with appropriate size is more favorable for enhancing the light trapping.
