Lake Aha in Guizhou Province, China is a medium-sized artificial reservoir with seasonally anoxic hypolimnion. Long-term sedimentary accumulation of iron and manganese resulted in their enrichment in the upper sedimen...Lake Aha in Guizhou Province, China is a medium-sized artificial reservoir with seasonally anoxic hypolimnion. Long-term sedimentary accumulation of iron and manganese resulted in their enrichment in the upper sediments. In anoxic season, Fe2+ and Mn2+ formed from bioledcal oxidation, would diffuse upto upper water from sediments. However, the concentration of Fe2+ incrlater and decreased earlier than that of Mn2+. Generally, Sulfate reduction occUrred at 6cm below the sediment-water interface. Whereas, in anoxic season, the reduction reached sediment top, inhibiting the release of Fe2+. As the oxidation of Mn2+ required molecular oxygen as catalyst, Serious anoxia caused the violent diffusion of Mn2+. Based on the bio-effects on the accumulation of Mn in natural fresh water, it’s necessary to seek a way to control manganese rerelease through accumulated manganese bacteria action.Keywrods: petdeopitional migration of Fe and Mn, biogaxhemical effect, Lake展开更多
To investigate the seasonal variability and potential environmental significance of trace elements in mountain glaciers, the surface snow and snow pit samples were collected at Urumqi Glacier No. 1 (43°06′N, 86...To investigate the seasonal variability and potential environmental significance of trace elements in mountain glaciers, the surface snow and snow pit samples were collected at Urumqi Glacier No. 1 (43°06′N, 86°49′E, 4 130 m a.s.l.), eastern Tianshan (天山), from September 2002 to September 2003, and analyzed for Li, V, Cr, Mn, Co, Cu, and Ba. The samples were acidified (leached) in a manner intended to reasonably approximate the extent to which the natural hydrologic and weathering cycles would liberate elements from mineral grains (dusts) in the ice and snow into the environment. The mean concentrations of Li, V, Cr, Mn, Co, Cu, and Ba are 0.2, 1.1, 0.8, 14.8, 0.1, 0.7, and 3.2 ng/g in surface snow but 1.0, 2.2, 1.8, 92.4, 0.8, 2.9, and 16.2 ng/g in snow pits, respectively. Input varies seasonally: in general, concentrations in the winter are higher than those in the summer. The trace elements are somewhat enriched (relative to expected abundances in material taken di- rectly from the earth's crust) and similar to what is observed in both pre-industrial and modern atmospheric dusts, although some anthropogenic components from nearby industrial cities may be present. Concentration vertical profiles can be redistributed in the post-depositional process, which may cause loss of trace elements in the summer.展开更多
ALD HfO2 films fabricated by a novel multi deposition multi annealing (MDMA) technique are inves- tigated, we have included samples both with and without a Ti scavenging layer. As compared to the reference gate stac...ALD HfO2 films fabricated by a novel multi deposition multi annealing (MDMA) technique are inves- tigated, we have included samples both with and without a Ti scavenging layer. As compared to the reference gate stack treated by conventional one-time deposition and annealing (D&A), devices receiving MDMA show a signif- icant reduction in leakage current. Meanwhile, EOT growth is effectively controlled by the Ti scavenging layer. This improvement strongly correlates with the cycle number of D&A (while keeping the total annealing time and total dielectrics thickness the same). Transmission electron microscope and energy-dispersive X-ray spectroscopy analysis suggests that oxygen incorporation into both the high-k film and the interfacial layer is likely to be re- sponsible for the improvement of the device. This novel MDMA is promising for the development of gate stack technology in a gate last integration scheme.展开更多
文摘Lake Aha in Guizhou Province, China is a medium-sized artificial reservoir with seasonally anoxic hypolimnion. Long-term sedimentary accumulation of iron and manganese resulted in their enrichment in the upper sediments. In anoxic season, Fe2+ and Mn2+ formed from bioledcal oxidation, would diffuse upto upper water from sediments. However, the concentration of Fe2+ incrlater and decreased earlier than that of Mn2+. Generally, Sulfate reduction occUrred at 6cm below the sediment-water interface. Whereas, in anoxic season, the reduction reached sediment top, inhibiting the release of Fe2+. As the oxidation of Mn2+ required molecular oxygen as catalyst, Serious anoxia caused the violent diffusion of Mn2+. Based on the bio-effects on the accumulation of Mn in natural fresh water, it’s necessary to seek a way to control manganese rerelease through accumulated manganese bacteria action.Keywrods: petdeopitional migration of Fe and Mn, biogaxhemical effect, Lake
基金supported by the Knowledge Innovation Project of Chinese Academy of Sciences (No. KZCX2-EW-311)the National Natural Science Foundation of China (Nos. 1141001040 and J0930003/J0109)+1 种基金the State Key Laboratory of Cryospheric Sciences Founding (No. SKLCS-ZZ-2010-04)the Program for New Century Excellent Talents in University from Ministry of Education of China (No. NCET-10-0019)
文摘To investigate the seasonal variability and potential environmental significance of trace elements in mountain glaciers, the surface snow and snow pit samples were collected at Urumqi Glacier No. 1 (43°06′N, 86°49′E, 4 130 m a.s.l.), eastern Tianshan (天山), from September 2002 to September 2003, and analyzed for Li, V, Cr, Mn, Co, Cu, and Ba. The samples were acidified (leached) in a manner intended to reasonably approximate the extent to which the natural hydrologic and weathering cycles would liberate elements from mineral grains (dusts) in the ice and snow into the environment. The mean concentrations of Li, V, Cr, Mn, Co, Cu, and Ba are 0.2, 1.1, 0.8, 14.8, 0.1, 0.7, and 3.2 ng/g in surface snow but 1.0, 2.2, 1.8, 92.4, 0.8, 2.9, and 16.2 ng/g in snow pits, respectively. Input varies seasonally: in general, concentrations in the winter are higher than those in the summer. The trace elements are somewhat enriched (relative to expected abundances in material taken di- rectly from the earth's crust) and similar to what is observed in both pre-industrial and modern atmospheric dusts, although some anthropogenic components from nearby industrial cities may be present. Concentration vertical profiles can be redistributed in the post-depositional process, which may cause loss of trace elements in the summer.
基金Project supported by the Integrated Circuit Advanced Process Center,Institute of Microelectronics of Chinese Academy of Sciences,and the Ministry of Technology,China
文摘ALD HfO2 films fabricated by a novel multi deposition multi annealing (MDMA) technique are inves- tigated, we have included samples both with and without a Ti scavenging layer. As compared to the reference gate stack treated by conventional one-time deposition and annealing (D&A), devices receiving MDMA show a signif- icant reduction in leakage current. Meanwhile, EOT growth is effectively controlled by the Ti scavenging layer. This improvement strongly correlates with the cycle number of D&A (while keeping the total annealing time and total dielectrics thickness the same). Transmission electron microscope and energy-dispersive X-ray spectroscopy analysis suggests that oxygen incorporation into both the high-k film and the interfacial layer is likely to be re- sponsible for the improvement of the device. This novel MDMA is promising for the development of gate stack technology in a gate last integration scheme.