An interfacial study between molten iron and the prereduced ilmenite with carbon was conducted at different melting temperatures by the sessile droplet method.The wetting characteristics between molten iron and the pr...An interfacial study between molten iron and the prereduced ilmenite with carbon was conducted at different melting temperatures by the sessile droplet method.The wetting characteristics between molten iron and the prereduced ilmenites with carbon were investigated by measuring contact angle of the droplet of molten iron on the prereduced ilmenite substrate.The images of the interface were also examined by the optical microscope and SEM equipped with EDS.The volume of molten iron increased with the melting temperature increasing when titania or high-content titania slag was used as the substrate.The contact angle decreased with the melting temperature increasing and it was independent on time at constant temperature.The contact angle was positively correlated with the reduction degree of the ilmenite,but the work of adhesion was negatively correlated with it.Higher smelting temperature was beneficial to the separation of iron and Ti oxides.The permeability of molten iron into the prereduced ilmenite with carbon was more obvious with reduction degree increasing owing to the high porosity of prereduced ilmenite.展开更多
Reduction ofnonpoint source pollutants, principally sediment and nutrients moving from cultivated fields to surface waters, is a major challenge. Remnants of once-extensive natural wetlands occur across the agricultur...Reduction ofnonpoint source pollutants, principally sediment and nutrients moving from cultivated fields to surface waters, is a major challenge. Remnants of once-extensive natural wetlands occur across the agricultural landscape, and it has been suggested that these areas might be managed to yield improved wetland function in terms of trapping and retention of nonpoint source pollutants. An existing wetland in a severed meander bend cut off in the 1940s from the Coldwater River in Tunica County, MS, USA was modified by the construction of weirs equipped with water control structures. The wetland was a segment o fold river channel about 500 m long and 20 m wide. Inputs to the wetland cell included sporadic flows due to runoff events from about 350 ha of cultivated fields and less frequent but larger flood events from the river. This type of flood event occurred only once during the study. Concentrations of sediment and nutrients in water were generally lower at the downstream end of the wetland cell than in the major inflow, an ephemeral slough. Mean values of turbidity, suspended sediment concentration, and concentrations of filterable and total phosphorus were 25% to 40% lower at the wetland cell discharge weir than in the slough. Mean concentrations of ammonia were 38% lower, but mean nitrate and nitrite concentrations were essentially unchanged by the wetland cell. Comparison of estimated input and output loads during periods when the wetland cell was not flooded by the river indicated that the wetland cell retained about 18% of input suspended sediment, 24% of phosphorus, and 29% of nitrogen input from cultivated fields. Wetland cell sediment and nutrient retention efficiency was treater for drier months, and declined durin~ wetter periods with frequent runoff events.展开更多
OBJECTIVE: To establish a method for rapid detection and sub-typing of human papilloma virus (HPV). METHODS: We utilized the piezoelectric genosensor (PG) technique, which is a combination of the piezoelectric biosens...OBJECTIVE: To establish a method for rapid detection and sub-typing of human papilloma virus (HPV). METHODS: We utilized the piezoelectric genosensor (PG) technique, which is a combination of the piezoelectric biosensor and gene chips for HPV identification in 22 recurrent biopsy specimens and 22 corresponding original biopsy specimens. The control samples came from normal tissue of healthy persons. A combined reaction took place on the sensor surface between the target genes and probes. The frequency of the piezoelectric sensor will decrease when such reactions occur, and the frequency decrease depends on the concentration of the target gene. Specimens were also analyzed with conventional PCR and dot blot. RESULTS: Of the 22 recurrent specimens, 15 contained HPV6 DNA, 2 HPV11 DNA, and 4 HPV16 DNA. Only one specimen was negative. All the 22 original specimens were positive: 17 harbored HPV6 DNA, 3 sequence homologous HPV11 DNA, and 2 HPV16 DNA. No HPV18 DNA was detected in any specimen. When compared with PCR and dot blot analysis, the results were essentially the same except for one specimen, which was shown to contain other sub-types of HPV. CONCLUSION: Our results show that the piezoelectric genosensor technique is a rapid and specific method to analyze HPV.展开更多
To understand road characteristics and landscape features associated with high road mortality of amphibians in Zoige Wetland National Nature Reserve, we surveyed road mortality along four major roads after rainfall in...To understand road characteristics and landscape features associated with high road mortality of amphibians in Zoige Wetland National Nature Reserve, we surveyed road mortality along four major roads after rainfall in May and September 2007. Road mortality of three species, Rana kukunoris, Nanorana pleskei and Bufo minshanicus, was surveyed across 225 transects （115 in May and 110 in September）. Transects were 100 m long and repeated every two kilometers along the four major roads. We used model averaging to assess factors that might determine amphibian road mortality. We recorded an average of 24.6 amphibian road mortalities per kilometer in May and 19.2 in September. Among road characteristics, road width was positively associated with road morality for R. kukunori and B. minshanicus. Traffic volume also increased the road mortality of B. minshanicus in September. Of the landscape features measured, area proportions of three types of grassland （wet, mesic and dry） within 1 km of the roads, particularly that of wet grassland, significantly increased road mortality for R. kukunori and total mortality across all three species. To most effectively reduce road mortality of amphibians in the Zoige wetlands, we suggest better road design such as avoiding wet grasslands, minimizing road width, underground passes and traffic control measures. The implementation of pub- lic transit in the area would reduce traffic volume, and hence mortality展开更多
基金Project(2008AA06Z1071) supported by the National High-tech Research and Development Program of China Project(50474043) supported by the National Natural Science Foundation of China
文摘An interfacial study between molten iron and the prereduced ilmenite with carbon was conducted at different melting temperatures by the sessile droplet method.The wetting characteristics between molten iron and the prereduced ilmenites with carbon were investigated by measuring contact angle of the droplet of molten iron on the prereduced ilmenite substrate.The images of the interface were also examined by the optical microscope and SEM equipped with EDS.The volume of molten iron increased with the melting temperature increasing when titania or high-content titania slag was used as the substrate.The contact angle decreased with the melting temperature increasing and it was independent on time at constant temperature.The contact angle was positively correlated with the reduction degree of the ilmenite,but the work of adhesion was negatively correlated with it.Higher smelting temperature was beneficial to the separation of iron and Ti oxides.The permeability of molten iron into the prereduced ilmenite with carbon was more obvious with reduction degree increasing owing to the high porosity of prereduced ilmenite.
文摘Reduction ofnonpoint source pollutants, principally sediment and nutrients moving from cultivated fields to surface waters, is a major challenge. Remnants of once-extensive natural wetlands occur across the agricultural landscape, and it has been suggested that these areas might be managed to yield improved wetland function in terms of trapping and retention of nonpoint source pollutants. An existing wetland in a severed meander bend cut off in the 1940s from the Coldwater River in Tunica County, MS, USA was modified by the construction of weirs equipped with water control structures. The wetland was a segment o fold river channel about 500 m long and 20 m wide. Inputs to the wetland cell included sporadic flows due to runoff events from about 350 ha of cultivated fields and less frequent but larger flood events from the river. This type of flood event occurred only once during the study. Concentrations of sediment and nutrients in water were generally lower at the downstream end of the wetland cell than in the major inflow, an ephemeral slough. Mean values of turbidity, suspended sediment concentration, and concentrations of filterable and total phosphorus were 25% to 40% lower at the wetland cell discharge weir than in the slough. Mean concentrations of ammonia were 38% lower, but mean nitrate and nitrite concentrations were essentially unchanged by the wetland cell. Comparison of estimated input and output loads during periods when the wetland cell was not flooded by the river indicated that the wetland cell retained about 18% of input suspended sediment, 24% of phosphorus, and 29% of nitrogen input from cultivated fields. Wetland cell sediment and nutrient retention efficiency was treater for drier months, and declined durin~ wetter periods with frequent runoff events.
基金supported by the National Natural Scienee Foundation of China(No．39870831)；the High-Tech Research and Development (863)Programme and the Key Technologies R&D Programme of the Nineth Five-vear Plan for the National Scientifie and Technological Development(No．96-A23-04-04)．
文摘OBJECTIVE: To establish a method for rapid detection and sub-typing of human papilloma virus (HPV). METHODS: We utilized the piezoelectric genosensor (PG) technique, which is a combination of the piezoelectric biosensor and gene chips for HPV identification in 22 recurrent biopsy specimens and 22 corresponding original biopsy specimens. The control samples came from normal tissue of healthy persons. A combined reaction took place on the sensor surface between the target genes and probes. The frequency of the piezoelectric sensor will decrease when such reactions occur, and the frequency decrease depends on the concentration of the target gene. Specimens were also analyzed with conventional PCR and dot blot. RESULTS: Of the 22 recurrent specimens, 15 contained HPV6 DNA, 2 HPV11 DNA, and 4 HPV16 DNA. Only one specimen was negative. All the 22 original specimens were positive: 17 harbored HPV6 DNA, 3 sequence homologous HPV11 DNA, and 2 HPV16 DNA. No HPV18 DNA was detected in any specimen. When compared with PCR and dot blot analysis, the results were essentially the same except for one specimen, which was shown to contain other sub-types of HPV. CONCLUSION: Our results show that the piezoelectric genosensor technique is a rapid and specific method to analyze HPV.
文摘To understand road characteristics and landscape features associated with high road mortality of amphibians in Zoige Wetland National Nature Reserve, we surveyed road mortality along four major roads after rainfall in May and September 2007. Road mortality of three species, Rana kukunoris, Nanorana pleskei and Bufo minshanicus, was surveyed across 225 transects （115 in May and 110 in September）. Transects were 100 m long and repeated every two kilometers along the four major roads. We used model averaging to assess factors that might determine amphibian road mortality. We recorded an average of 24.6 amphibian road mortalities per kilometer in May and 19.2 in September. Among road characteristics, road width was positively associated with road morality for R. kukunori and B. minshanicus. Traffic volume also increased the road mortality of B. minshanicus in September. Of the landscape features measured, area proportions of three types of grassland （wet, mesic and dry） within 1 km of the roads, particularly that of wet grassland, significantly increased road mortality for R. kukunori and total mortality across all three species. To most effectively reduce road mortality of amphibians in the Zoige wetlands, we suggest better road design such as avoiding wet grasslands, minimizing road width, underground passes and traffic control measures. The implementation of pub- lic transit in the area would reduce traffic volume, and hence mortality
