Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza haematocheilus, flathead fish Platycephalus indicus, sea bass Lateolabrax japonicus, macke...Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza haematocheilus, flathead fish Platycephalus indicus, sea bass Lateolabrax japonicus, mackerel Scomberomorus niphonius and silver pomfret Pampus argenteus) collected from Laizhou Bay in the Bohai Sea of China were investigated. The results indicate that Hg bioaccumulation in the five fish was tissue- specific, with the highest levels in the muscle and liver, followed by the stomach and gonads. The lowest levels were found in the gills and skin. Fish at higher trophic levels (flathead fish and sea bass) exhibited higher Hg concentrations than consumers at lower trophic levels. Mercury bioaccumulation tended to be positively correlated with fish length in mullet, silver pomfret, mackerel, and flathead fish, but was negatively correlated with fish length in sea bass. The Hg concentrations in the muscles of all fish species in Laizhou Bay were within the permissible limits of food safety set by national and international criteria. However, the suggesting maximum consumption of sea bass is 263g per week for human health.展开更多
The gas enrichment conditions in the Fuxin basin are compared to those of the Powder River basin.The coal bed depth,the gas content,the individual coal bed layer thickness,and the overall structure thickness of the Po...The gas enrichment conditions in the Fuxin basin are compared to those of the Powder River basin.The coal bed depth,the gas content,the individual coal bed layer thickness,and the overall structure thickness of the Powder River basin in the U.S.were examined.The main factors affecting gas enrichment were examined.These factors include the coal-forming environment,the gas sources,the geological structure,the presence of magmatic activity,and the local hydrology.The coal-bed gas enrichment area in the Wangying-Liujia block of the Fuxin basin is then discussed by analogy.A hydrodynamic-force/dike-plugging model based on a magma fractured bed is proposed to explain the gas enrichment in this part of the Fuxin basin.High gas production is predicted in areas having similar conditions.This work will aid future coal-bed gas exploration and development.展开更多
Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex l...Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex laminated plates is presented. In addition, using displacement as a basic unknown quantity, the accurate analytical series solution for the problem of strata movement induced by extraction of horizontal seam is worked out when crosswise isotropic elastic layers are in sliding contact condition. A new approach is put forward to solve the complicated system of mining subsidence.展开更多
基金Supported by the National Natural Science Foundation of China for International or Regional Research Cooperation and Exchange Project(No.31061160187)the National Natural Science Foundation of China for Creative Research Group(No.41121064)
文摘Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza haematocheilus, flathead fish Platycephalus indicus, sea bass Lateolabrax japonicus, mackerel Scomberomorus niphonius and silver pomfret Pampus argenteus) collected from Laizhou Bay in the Bohai Sea of China were investigated. The results indicate that Hg bioaccumulation in the five fish was tissue- specific, with the highest levels in the muscle and liver, followed by the stomach and gonads. The lowest levels were found in the gills and skin. Fish at higher trophic levels (flathead fish and sea bass) exhibited higher Hg concentrations than consumers at lower trophic levels. Mercury bioaccumulation tended to be positively correlated with fish length in mullet, silver pomfret, mackerel, and flathead fish, but was negatively correlated with fish length in sea bass. The Hg concentrations in the muscles of all fish species in Laizhou Bay were within the permissible limits of food safety set by national and international criteria. However, the suggesting maximum consumption of sea bass is 263g per week for human health.
基金supported by the National Science and Tech-nology Major Project(No.2008ZX05033)the National Basic Research Program of China(No.2009CB219601)
文摘The gas enrichment conditions in the Fuxin basin are compared to those of the Powder River basin.The coal bed depth,the gas content,the individual coal bed layer thickness,and the overall structure thickness of the Powder River basin in the U.S.were examined.The main factors affecting gas enrichment were examined.These factors include the coal-forming environment,the gas sources,the geological structure,the presence of magmatic activity,and the local hydrology.The coal-bed gas enrichment area in the Wangying-Liujia block of the Fuxin basin is then discussed by analogy.A hydrodynamic-force/dike-plugging model based on a magma fractured bed is proposed to explain the gas enrichment in this part of the Fuxin basin.High gas production is predicted in areas having similar conditions.This work will aid future coal-bed gas exploration and development.
文摘Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex laminated plates is presented. In addition, using displacement as a basic unknown quantity, the accurate analytical series solution for the problem of strata movement induced by extraction of horizontal seam is worked out when crosswise isotropic elastic layers are in sliding contact condition. A new approach is put forward to solve the complicated system of mining subsidence.
