This paper reports study focusing on the effects of sloping bottom on the deep cross-equatorial boundary current, and discusses model and laboratory experiment results showing that the southward that the southward int...This paper reports study focusing on the effects of sloping bottom on the deep cross-equatorial boundary current, and discusses model and laboratory experiment results showing that the southward that the southward intrusion distance and flow speed of the western boundary current depend on the bottom slope variation rate,the difference between and and are the current thickness at eastward edge and westward edge, respectively), and the net mass transport.展开更多
The induced electricity of 110 kV transmission lines which cross the UHV AC transmission lines may threaten personal safety of the maintenance staff. In this paper, field measurement of the induced voltage and induced...The induced electricity of 110 kV transmission lines which cross the UHV AC transmission lines may threaten personal safety of the maintenance staff. In this paper, field measurement of the induced voltage and induced current on a 110 kV crossing line inside Jinhua in Zhejiang province is performed. The electrostatic induced voltage on the measured line is 12.24 kV. The power frequency electromagnetic field simulation model is established, and the calculation results are consistent with the measured. Influence factors analysis shows that the electrostatic induced voltage on the 110 kV line is 12.78 kV, the electromagnetic induced voltage is 12.3 V, the induced current through ground wire is less than 1A when the UHV lines operate at full load. The induced voltage and current decrease while the crossing distance increases. Parallel lines induction is much higher than crossing lines. The electromagnetic induced voltage after ground knife-switch shut down would exceed the human safety voltage 36 V while the crossing angle is less than 30?, so the temporary ground wire must be hanged to ensure safety of the maintenance staff.展开更多
Along the downwelling coast off Western Australia, late-austral-autumn/early-austral-winter chlorophyll a blooms are observed on the continental shelf south of the Shark Bay (26° S). The late-austral-autumn/early...Along the downwelling coast off Western Australia, late-austral-autumn/early-austral-winter chlorophyll a blooms are observed on the continental shelf south of the Shark Bay (26° S). The late-austral-autumn/early-austral-winter blooms are in phase with seasonal strengthening of the Leeuwin Current and its eddy field. From satellite altimeter and ocean color data , anticyclonic eddies are found to entrain the high phytoplankton biomass waters from the shelf and transport them offshore into the oligotrophic, subtropical marine environment. The late-austral-autumn/early-austral-winter blooms are highly linked with enhanced horizontal mixing by mesoscale eddies in the region, as derived from the finite-size Lyapunov exponent (FSLE) of the surface geostrophic flow field obtained from satellite altimeter data. The pathways of cross-shelf exchanges, which are mostly driven by the mesoscale eddies, are revealed with coalescing of the FSLE of the surface geostrophic flow field and the satellite chlorophyll a images.展开更多
Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler （ADCP） instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin （mainly focusing on Makou ...Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler （ADCP） instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin （mainly focusing on Makou and Tianjiazhen river reach）. Hydrodynamic properties of river channels were also discussed. The research results indicate that nonlinear relationships can be identified between river-width/river-depth ratio （W/D ratio）, sizes of cross section and mean flow velocity. Positive relations are detected between W/D ratio and mean flow velocity when W/D〈1; and negative relations are observed when W/D〉1. Adverse relationships can be obtained between W/D ratio and cross-section area. Geomorphologic and geologic survey indicates different components of river banks in the wider and narrower river reaches respectively. These may be the main driving factors causing unique hydrological properties of river channels in the middle Yangtze River basin. Narrower river cross sections tend to raise water level in the upstream river reach near narrower river channel, giving rise to backwater effects. River knots can cause serious backwater effects, which is harmful for flood mitigation. However river knots will also stabilize river channel and this will be beneficial for river channel management. The results of this paper may be helpful for flood mitigation and river channel management in the middle Yangtze River basin.展开更多
Using the Grad-Shafranov equation, the magnetic configuration is obtained. With this configuration, Brambilla＇s ray tracing theory has been used to study the propagation of LH waves. The qualitative study of the feas...Using the Grad-Shafranov equation, the magnetic configuration is obtained. With this configuration, Brambilla＇s ray tracing theory has been used to study the propagation of LH waves. The qualitative study of the feasibility of LHCD in the non-circular cross section tokamak HL-2A is made. The optimized current drive method is discussed.展开更多
文摘This paper reports study focusing on the effects of sloping bottom on the deep cross-equatorial boundary current, and discusses model and laboratory experiment results showing that the southward that the southward intrusion distance and flow speed of the western boundary current depend on the bottom slope variation rate,the difference between and and are the current thickness at eastward edge and westward edge, respectively), and the net mass transport.
文摘The induced electricity of 110 kV transmission lines which cross the UHV AC transmission lines may threaten personal safety of the maintenance staff. In this paper, field measurement of the induced voltage and induced current on a 110 kV crossing line inside Jinhua in Zhejiang province is performed. The electrostatic induced voltage on the measured line is 12.24 kV. The power frequency electromagnetic field simulation model is established, and the calculation results are consistent with the measured. Influence factors analysis shows that the electrostatic induced voltage on the 110 kV line is 12.78 kV, the electromagnetic induced voltage is 12.3 V, the induced current through ground wire is less than 1A when the UHV lines operate at full load. The induced voltage and current decrease while the crossing distance increases. Parallel lines induction is much higher than crossing lines. The electromagnetic induced voltage after ground knife-switch shut down would exceed the human safety voltage 36 V while the crossing angle is less than 30?, so the temporary ground wire must be hanged to ensure safety of the maintenance staff.
基金supported by Strategic Research Fund for Marine Environment
文摘Along the downwelling coast off Western Australia, late-austral-autumn/early-austral-winter chlorophyll a blooms are observed on the continental shelf south of the Shark Bay (26° S). The late-austral-autumn/early-austral-winter blooms are in phase with seasonal strengthening of the Leeuwin Current and its eddy field. From satellite altimeter and ocean color data , anticyclonic eddies are found to entrain the high phytoplankton biomass waters from the shelf and transport them offshore into the oligotrophic, subtropical marine environment. The late-austral-autumn/early-austral-winter blooms are highly linked with enhanced horizontal mixing by mesoscale eddies in the region, as derived from the finite-size Lyapunov exponent (FSLE) of the surface geostrophic flow field obtained from satellite altimeter data. The pathways of cross-shelf exchanges, which are mostly driven by the mesoscale eddies, are revealed with coalescing of the FSLE of the surface geostrophic flow field and the satellite chlorophyll a images.
基金National Natural Science Foundation of China,No.40701015Key Project of National Natural Science Foundation of China,No.40730635
文摘Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler （ADCP） instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin （mainly focusing on Makou and Tianjiazhen river reach）. Hydrodynamic properties of river channels were also discussed. The research results indicate that nonlinear relationships can be identified between river-width/river-depth ratio （W/D ratio）, sizes of cross section and mean flow velocity. Positive relations are detected between W/D ratio and mean flow velocity when W/D〈1; and negative relations are observed when W/D〉1. Adverse relationships can be obtained between W/D ratio and cross-section area. Geomorphologic and geologic survey indicates different components of river banks in the wider and narrower river reaches respectively. These may be the main driving factors causing unique hydrological properties of river channels in the middle Yangtze River basin. Narrower river cross sections tend to raise water level in the upstream river reach near narrower river channel, giving rise to backwater effects. River knots can cause serious backwater effects, which is harmful for flood mitigation. However river knots will also stabilize river channel and this will be beneficial for river channel management. The results of this paper may be helpful for flood mitigation and river channel management in the middle Yangtze River basin.
基金the National Science Foundation of China(Nos.10675043,10575031 and 10675042)
文摘Using the Grad-Shafranov equation, the magnetic configuration is obtained. With this configuration, Brambilla＇s ray tracing theory has been used to study the propagation of LH waves. The qualitative study of the feasibility of LHCD in the non-circular cross section tokamak HL-2A is made. The optimized current drive method is discussed.
