The water level of the Three Gorges Reservoir(TGR) rose to 172.5 m in two stages from September to November,2008.The hydrodynamic parameters and water quality parameters(e.g.flow velocity,temperature,turbidity and nut...The water level of the Three Gorges Reservoir(TGR) rose to 172.5 m in two stages from September to November,2008.The hydrodynamic parameters and water quality parameters(e.g.flow velocity,temperature,turbidity and nutrient content) had been continuously monitored to reveal the influence of the impounding process of the TGR on the water eutrophication in the Xiangxi Bay(XXB).The maximal daily rise of the water level of the TGR was about 2.38 m.The water exchange between the mainstream(the Changjiang River) and the XXB of the TGR was enhanced by density current,and its main characteristics were a density-stratified flow in different directions.The water exchange reduced the differences of the water quality parameters(for example,temperature,turbidity,nutrient level,pH,etc.) between the mainstream and the XXB during the impounding process.Meanwhile,the water stability index in the mainstream remained small but it was lowered in the XXB.The main causes included the dilution by water of lower concentration of the chlorophyll a(Chl.a) entering from the mainstream,the decline of the water stability,and the increase of suspended silt,which induced the Chl.a to decrease in the XXB during the impounding process.The grade of the water eutrophication changed from middle eutrophic level to mesotrophic state in the process.However,as available nutrients were imported into the XXB from the mainstream during the impounding process the risk of water eutrophication increases in the XXB in the future.展开更多
There are some active bottom currents on the northern continental slope of the South China Sea (SCS). Reflection seismic profiles show that the bottom current channels occur in the water depth range of 1000 to 2700 m,...There are some active bottom currents on the northern continental slope of the South China Sea (SCS). Reflection seismic profiles show that the bottom current channels occur in the water depth range of 1000 to 2700 m,extending from the NE to the SW,leading to accumulation of discontinuous drifts with higher sedimentation rates on the eastern side of the channel. The stacking pattern of the layers sug-gests that these drifts propagated southwestward,following the direction of the bottom currents. One sedimentary drift to the southeast of the Dongsha Islands has the highest sedimentation rate of 97cm/ka in the last 12 ka. The sedimentary characteristics of the sediment layers indicate that these bottom currents are most likley caused by the water movement of a branch of the West Pacific Ocean Current,which enters the northern SCS via the Bashi Strait. Once formed,the bottom currents trans-port sediments along the northern slope of SCS southwestward and finally disappear into the central basin of the SCS. Due to the bottom current activity,the deep-sea sedimentary process in the northern SCS is complex.展开更多
This paper proposes the design of a novel DC current flow controller(CFC)and evaluates the control performance of balancing and regulating the DC branch currents using the DC CFC in a meshed multi-terminal HVDC(MTDC)g...This paper proposes the design of a novel DC current flow controller(CFC)and evaluates the control performance of balancing and regulating the DC branch currents using the DC CFC in a meshed multi-terminal HVDC(MTDC)grid.The DC CFC consists of two identical full bridge DC-DC converters with the capacitors of the two converters being connected in parallel.The scalability of the DC CFC is easily achievable due to the identical bridge converter topology;the cost of this DC CFC is also relatively low due to its simple physical structure and low voltage ratings.The control performance of the DC CFC is tested on a meshed 3-terminal(3-T)HVDC grid,which is based on modular multilevel converters(MMC).The DC branch current control in the meshed MTDC grid is achieved using the proposed control strategy of the DC CFC,and is verified through case studies on the real-time digital simulator(RTDS).展开更多
Spinal cord injury is linked to the interruption of neural pathways,which results in irreversible neural dysfunction.Neural repair and neuroregeneration are critical goals and issues for rehabilitation in spinal cord ...Spinal cord injury is linked to the interruption of neural pathways,which results in irreversible neural dysfunction.Neural repair and neuroregeneration are critical goals and issues for rehabilitation in spinal cord injury,which require neural stem cell repair and multimodal neuromodulation techniques involving personalized rehabilitation strategies.Besides the involvement of endogenous stem cells in neurogenesis and neural repair,exogenous neural stem cell transplantation is an emerging effective method for repairing and replacing damaged tissues in central nervous system diseases.However,to ensure that endogenous or exogenous neural stem cells truly participate in neural repair following spinal cord injury,appropriate interventional measures(e.g.,neuromodulation)should be adopted.Neuromodulation techniques,such as noninvasive magnetic stimulation and electrical stimulation,have been safely applied in many neuropsychiatric diseases.There is increasing evidence to suggest that neuromagnetic/electrical modulation promotes neuroregeneration and neural repair by affecting signaling in the nervous system;namely,by exciting,inhibiting,or regulating neuronal and neural network activities to improve motor function and motor learning following spinal cord injury.Several studies have indicated that fine motor skill rehabilitation training makes use of residual nerve fibers for collateral growth,encourages the formation of new synaptic connections to promote neural plasticity,and improves motor function recovery in patients with spinal cord injury.With the development of biomaterial technology and biomechanical engineering,several emerging treatments have been developed,such as robots,brain-computer interfaces,and nanomaterials.These treatments have the potential to help millions of patients suffering from motor dysfunction caused by spinal cord injury.However,large-scale clinical trials need to be conducted to validate their efficacy.This review evaluated the efficacy of neural stem cells and magnetic or electrical stimu展开更多
The gridded （1/3°＊1/3°） altimetry data from October 1992 through December 2004 were analyzed to study the seasonal and interannual variabilities of the bifurcation of the North Equatorial Current （NEC） ...The gridded （1/3°＊1/3°） altimetry data from October 1992 through December 2004 were analyzed to study the seasonal and interannual variabilities of the bifurcation of the North Equatorial Current （NEC） at the surface in the western North Pacific Ocean. Calculations show that on annual average the bifurcation occurs at about 13.4°N at the surface. The geostrophic flow derived from Sea Surface Height （SSH） data shows that the southernmost latitude of the NEC bifurcation at the surface is about 12.9°N in June and the northernmost latitude is about 14.1°N in December. Correlation analyses between the bifurcation latitude and the Southern Oscillation Index （SOl） suggest that the bifurcation latitude is highly correlated with the E1 Nino/Southern Oscillation （ENSO） events. During the E1 Nino years the bifurcation of the NEC takes place at higher latitudes and vice versa.展开更多
The Yellow Sea Warm Current （YSWC） penetrates northward along the Yellow Sea Trough, and brings warm and saline water towards the Bohai Sea. The YSWC becomes much less intrusive in summer and is limited mostly in th...The Yellow Sea Warm Current （YSWC） penetrates northward along the Yellow Sea Trough, and brings warm and saline water towards the Bohai Sea. The YSWC becomes much less intrusive in summer and is limited mostly in the southern trough, contrasting with a deep winter penetration well into the trough. The seasonal variability of the YSWC has prompted a debate regarding which controls the YSWC and its seasonal variability. In this article, the annual mean and seasonal variability of the YSWC was examined by using a 3-D ocean model together with several experiments. The results show that in the annual mean the YSWC is a compensating current firstly for the southward Korea Coastal Current （KCC）, which is mainly caused by the Kuroshio Current （KC）. The local wind-stress forcing plays an important but secondary role. However, the local monsoonal forcing plays a prominent role in modulating the seasonal variability. A deep northwestward intrusion of the YSWC in winter, for instance, is mainly due to a robustly developed China Coastal Current （CCC） which draws water along the Yellow Sea trough to feed a southward flow all the way from the Bohai Sea to the Taiwan Strait.展开更多
基金supported by the National Natural Science Foundation of China (Grant No 50679038)"115" Science and Technology Supporting of China (Grant No 2008BA B29B09)the Natural Science and Technology Major Special Program of China (Grant No 2008ZX07104-004)
文摘The water level of the Three Gorges Reservoir(TGR) rose to 172.5 m in two stages from September to November,2008.The hydrodynamic parameters and water quality parameters(e.g.flow velocity,temperature,turbidity and nutrient content) had been continuously monitored to reveal the influence of the impounding process of the TGR on the water eutrophication in the Xiangxi Bay(XXB).The maximal daily rise of the water level of the TGR was about 2.38 m.The water exchange between the mainstream(the Changjiang River) and the XXB of the TGR was enhanced by density current,and its main characteristics were a density-stratified flow in different directions.The water exchange reduced the differences of the water quality parameters(for example,temperature,turbidity,nutrient level,pH,etc.) between the mainstream and the XXB during the impounding process.Meanwhile,the water stability index in the mainstream remained small but it was lowered in the XXB.The main causes included the dilution by water of lower concentration of the chlorophyll a(Chl.a) entering from the mainstream,the decline of the water stability,and the increase of suspended silt,which induced the Chl.a to decrease in the XXB during the impounding process.The grade of the water eutrophication changed from middle eutrophic level to mesotrophic state in the process.However,as available nutrients were imported into the XXB from the mainstream during the impounding process the risk of water eutrophication increases in the XXB in the future.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 40276019 and 40238060)the National Key Basic Research Special Foundation Project of China (Grant No. G2000078500)
文摘There are some active bottom currents on the northern continental slope of the South China Sea (SCS). Reflection seismic profiles show that the bottom current channels occur in the water depth range of 1000 to 2700 m,extending from the NE to the SW,leading to accumulation of discontinuous drifts with higher sedimentation rates on the eastern side of the channel. The stacking pattern of the layers sug-gests that these drifts propagated southwestward,following the direction of the bottom currents. One sedimentary drift to the southeast of the Dongsha Islands has the highest sedimentation rate of 97cm/ka in the last 12 ka. The sedimentary characteristics of the sediment layers indicate that these bottom currents are most likley caused by the water movement of a branch of the West Pacific Ocean Current,which enters the northern SCS via the Bashi Strait. Once formed,the bottom currents trans-port sediments along the northern slope of SCS southwestward and finally disappear into the central basin of the SCS. Due to the bottom current activity,the deep-sea sedimentary process in the northern SCS is complex.
基金supported by UK-China Smart Grid Project ERIFT via UK EPSRC,University of Birmingham SiGuang Li Scholarship and China Scholarship Council。
文摘This paper proposes the design of a novel DC current flow controller(CFC)and evaluates the control performance of balancing and regulating the DC branch currents using the DC CFC in a meshed multi-terminal HVDC(MTDC)grid.The DC CFC consists of two identical full bridge DC-DC converters with the capacitors of the two converters being connected in parallel.The scalability of the DC CFC is easily achievable due to the identical bridge converter topology;the cost of this DC CFC is also relatively low due to its simple physical structure and low voltage ratings.The control performance of the DC CFC is tested on a meshed 3-terminal(3-T)HVDC grid,which is based on modular multilevel converters(MMC).The DC branch current control in the meshed MTDC grid is achieved using the proposed control strategy of the DC CFC,and is verified through case studies on the real-time digital simulator(RTDS).
基金supported by the Major International(Regional)Joint Research Project of the National Natural Science Foundation of China,No.81820108013(to LMC)the General Research Project of the National Natural Science Foundation of China,No.81772453(to DSX)the National Key Research and Development Program of China,No.2016YFA0100800(to LMC)
文摘Spinal cord injury is linked to the interruption of neural pathways,which results in irreversible neural dysfunction.Neural repair and neuroregeneration are critical goals and issues for rehabilitation in spinal cord injury,which require neural stem cell repair and multimodal neuromodulation techniques involving personalized rehabilitation strategies.Besides the involvement of endogenous stem cells in neurogenesis and neural repair,exogenous neural stem cell transplantation is an emerging effective method for repairing and replacing damaged tissues in central nervous system diseases.However,to ensure that endogenous or exogenous neural stem cells truly participate in neural repair following spinal cord injury,appropriate interventional measures(e.g.,neuromodulation)should be adopted.Neuromodulation techniques,such as noninvasive magnetic stimulation and electrical stimulation,have been safely applied in many neuropsychiatric diseases.There is increasing evidence to suggest that neuromagnetic/electrical modulation promotes neuroregeneration and neural repair by affecting signaling in the nervous system;namely,by exciting,inhibiting,or regulating neuronal and neural network activities to improve motor function and motor learning following spinal cord injury.Several studies have indicated that fine motor skill rehabilitation training makes use of residual nerve fibers for collateral growth,encourages the formation of new synaptic connections to promote neural plasticity,and improves motor function recovery in patients with spinal cord injury.With the development of biomaterial technology and biomechanical engineering,several emerging treatments have been developed,such as robots,brain-computer interfaces,and nanomaterials.These treatments have the potential to help millions of patients suffering from motor dysfunction caused by spinal cord injury.However,large-scale clinical trials need to be conducted to validate their efficacy.This review evaluated the efficacy of neural stem cells and magnetic or electrical stimu
基金Project supported by the National Natural Science Foundation of China (Grants Nos: D06-40552002, 40576016) the Qingdao Municipal Bureau of Science and Technology (Grant No: 02-KJYSH-03).
文摘The gridded （1/3°＊1/3°） altimetry data from October 1992 through December 2004 were analyzed to study the seasonal and interannual variabilities of the bifurcation of the North Equatorial Current （NEC） at the surface in the western North Pacific Ocean. Calculations show that on annual average the bifurcation occurs at about 13.4°N at the surface. The geostrophic flow derived from Sea Surface Height （SSH） data shows that the southernmost latitude of the NEC bifurcation at the surface is about 12.9°N in June and the northernmost latitude is about 14.1°N in December. Correlation analyses between the bifurcation latitude and the Southern Oscillation Index （SOl） suggest that the bifurcation latitude is highly correlated with the E1 Nino/Southern Oscillation （ENSO） events. During the E1 Nino years the bifurcation of the NEC takes place at higher latitudes and vice versa.
基金Project supported by the National Basic Research Program of China (973 programs, Grant Nos.2005CB422303, 2007CB411804)the National Natural Science Foundation of China (Grant No. 40706006)+1 种基金the Key Project of International Science and Technology Cooperation of China (Grant No.2006DFB21250)the 111 Project (Grant No.B07036).
文摘The Yellow Sea Warm Current （YSWC） penetrates northward along the Yellow Sea Trough, and brings warm and saline water towards the Bohai Sea. The YSWC becomes much less intrusive in summer and is limited mostly in the southern trough, contrasting with a deep winter penetration well into the trough. The seasonal variability of the YSWC has prompted a debate regarding which controls the YSWC and its seasonal variability. In this article, the annual mean and seasonal variability of the YSWC was examined by using a 3-D ocean model together with several experiments. The results show that in the annual mean the YSWC is a compensating current firstly for the southward Korea Coastal Current （KCC）, which is mainly caused by the Kuroshio Current （KC）. The local wind-stress forcing plays an important but secondary role. However, the local monsoonal forcing plays a prominent role in modulating the seasonal variability. A deep northwestward intrusion of the YSWC in winter, for instance, is mainly due to a robustly developed China Coastal Current （CCC） which draws water along the Yellow Sea trough to feed a southward flow all the way from the Bohai Sea to the Taiwan Strait.
