The purpose of this paper is to apply ＂Soil and Water Assessment Tool （SWAT）＂ model to assess the impacts of climate change and deforestation on stream discharge and sediment yield from Phu Luong watershed in Nort...The purpose of this paper is to apply ＂Soil and Water Assessment Tool （SWAT）＂ model to assess the impacts of climate change and deforestation on stream discharge and sediment yield from Phu Luong watershed in Northern Viet Nam. Among the three climate change scenarios B 1, B2, and A2, representing low, medium, and high levels of greenhouse gas emission, respectively were set up for Viet Nam, the B2 scenario was selected for this study. Two land use scenarios （S1-2030 and $2-2050） were formulated combination with climate change in WSAT simulation. In B2 climate change scenario, mean temperature increases 0.7℃（2030） and 1.3 ℃ （2050）; annual rainfall increases 2.1% （2030） and 3.80% （2050） respect to baseline scenario. The results show that the stream discharge is likely to increase in the future during the wet season with increasing threats of sedimentation.展开更多
The cleanliness of gasoline is related to its components and properties.All commercial gasoline builds up deposits on the engine's injector,intake valve and combustion chamber,which can significantly lower the eng...The cleanliness of gasoline is related to its components and properties.All commercial gasoline builds up deposits on the engine's injector,intake valve and combustion chamber,which can significantly lower the engine performance and influence exhaust gas emissions.In this study,the intake valve deposits (IVD) and combustion chamber deposits (CCD) produced from combustion of fuel containing 21 v%—42 v% of aromatics and 8 v%—31 v% of olefins have been studied using Ford engine tests,and the characteristics of deposits were studied by IR spectroscopy,TGA and elemental analysis instrument.The test results have shown that deposit formation depends on the fuel composition,especially the aromatic content in the fuel.It is also observed that there are differences in the values of IVD and CCD measured by IR spectrometry and elemental analyses.展开更多
In this work,silicon-germanium(SiGe)thin films are epitaxially grown on Ge substrates by ultra-high vacuum chemical vapor deposition and then doped with Mn element by ion-implantation and subsequent rapid thermal anne...In this work,silicon-germanium(SiGe)thin films are epitaxially grown on Ge substrates by ultra-high vacuum chemical vapor deposition and then doped with Mn element by ion-implantation and subsequent rapid thermal annealing(RTA).The characterizations show that the epitaxial SiGe thin films are single-crystalline with uniform tensile strain and then become polycrystalline after the ion implantation and following RTA.The magnetization measurements indicate that the annealed thin films exhibit Mn concentration-dependent ferromagnetism up to 309 K and the X-ray magnetic circular dichroism characterizations reveal the spin and orbital magnetic moments from the substitutional Mn element.To minimize the influence of anomalous Hall effect,magneto-transport measurements at a high magnetic field up to 31 T at 300 K are performed to obtain the hole mobility,which reaches a record-high value of~1230 cm^(2)V^(-1)s^(-1),owing to the crystalline quality and tensile strain-induced energy band modulation of the samples.The first demonstration of Mn-doped SiGe thin films with roomtemperature ferromagnetism and high carrier mobility may pave the way for practical semiconductor spintronic applications.展开更多
Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer...Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.展开更多
文摘The purpose of this paper is to apply ＂Soil and Water Assessment Tool （SWAT）＂ model to assess the impacts of climate change and deforestation on stream discharge and sediment yield from Phu Luong watershed in Northern Viet Nam. Among the three climate change scenarios B 1, B2, and A2, representing low, medium, and high levels of greenhouse gas emission, respectively were set up for Viet Nam, the B2 scenario was selected for this study. Two land use scenarios （S1-2030 and $2-2050） were formulated combination with climate change in WSAT simulation. In B2 climate change scenario, mean temperature increases 0.7℃（2030） and 1.3 ℃ （2050）; annual rainfall increases 2.1% （2030） and 3.80% （2050） respect to baseline scenario. The results show that the stream discharge is likely to increase in the future during the wet season with increasing threats of sedimentation.
基金the PetroChina Corporation Research and Development Project (06-03B-01-01) for financial support
文摘The cleanliness of gasoline is related to its components and properties.All commercial gasoline builds up deposits on the engine's injector,intake valve and combustion chamber,which can significantly lower the engine performance and influence exhaust gas emissions.In this study,the intake valve deposits (IVD) and combustion chamber deposits (CCD) produced from combustion of fuel containing 21 v%—42 v% of aromatics and 8 v%—31 v% of olefins have been studied using Ford engine tests,and the characteristics of deposits were studied by IR spectroscopy,TGA and elemental analysis instrument.The test results have shown that deposit formation depends on the fuel composition,especially the aromatic content in the fuel.It is also observed that there are differences in the values of IVD and CCD measured by IR spectrometry and elemental analyses.
基金supported by the National Key Research and Development Program of China(2017YFB0405702)the National Natural Science Foundation of China(52172272)。
文摘In this work,silicon-germanium(SiGe)thin films are epitaxially grown on Ge substrates by ultra-high vacuum chemical vapor deposition and then doped with Mn element by ion-implantation and subsequent rapid thermal annealing(RTA).The characterizations show that the epitaxial SiGe thin films are single-crystalline with uniform tensile strain and then become polycrystalline after the ion implantation and following RTA.The magnetization measurements indicate that the annealed thin films exhibit Mn concentration-dependent ferromagnetism up to 309 K and the X-ray magnetic circular dichroism characterizations reveal the spin and orbital magnetic moments from the substitutional Mn element.To minimize the influence of anomalous Hall effect,magneto-transport measurements at a high magnetic field up to 31 T at 300 K are performed to obtain the hole mobility,which reaches a record-high value of~1230 cm^(2)V^(-1)s^(-1),owing to the crystalline quality and tensile strain-induced energy band modulation of the samples.The first demonstration of Mn-doped SiGe thin films with roomtemperature ferromagnetism and high carrier mobility may pave the way for practical semiconductor spintronic applications.
基金supported by the National Natural Science Foundation of China (Grant Nos.60577030,60776041,60876035)the National Key Basic Research Special Foundation of China (Grant Nos.TG2007CB307004,2006CB921607)
文摘Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.
