AThe wastewater source of 4# tailing pond in Dexing copper mine consists of alkaline flotation pulp and acid mine drainage (AMD) from the nearby opencast mine. Therefore, the heavy metals in tailing ore are very lik...AThe wastewater source of 4# tailing pond in Dexing copper mine consists of alkaline flotation pulp and acid mine drainage (AMD) from the nearby opencast mine. Therefore, the heavy metals in tailing ore are very likely to be released due to acidification from AMD. The leaching behaviors ofZn, Cu, Fe and Mn in mine tailings from Dexing copper mine were investigated by a series of laboratory batch experiments. The effectcs ofpH, temperature, particle size and contact time on the leachability of such heavy metals were examined. It was evident that Zn, Cu, Fe and Mn were major heavy metals in the tailings while gangue minerals like quartz were major constituents in examined tailings. The tailing dissolution reaction was controlled by the acid, whose kinetics could be expressed according to the heterogeneous reaction models and explained by a shrinking core model with the surface chemical reaction as the rate-controlling step. The leachability of all metals examined depended on pH and contact time. The batch studies indicated that the maximum leaching ratios ofZn, Cu, Fe and Mn at pH 2.0 were 5.4%, 5.8%, l 1.1% and 34.1%, respectively. The dissolubility of all metals examined was positively correlated to the temperatures. The particle size would not change dissolution tendency of those heavy metals, but decrease the concentrations of leached heavy metals.展开更多
Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the f...Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the first arrivals. Hence, first arrivals cannot be used to detect small seismic velocity variations. However, small variations can be reliably detected by the coda waves because of the amplification owing to multiple scattering. We investigate the ability of coda wave interferometry to detect seismic velocity variations and monitor time-lapse reservoir characteristics using numerical simulations and experimental data. We use the Marmousi II model and finite-difference methods to build model seismic data and introduce small seismic velocity variations in the target layer. We examine the model seismic data before and after the changes and observe the coda waves. We find that velocity changes can be detected by coda wave interferometry and demonstrate that coda wave interferometry can be used in monitoring time- lapse reservoir characteristics.展开更多
The turbulent wakes behind trailing edge are analyzed for understanding of the flow mechanisms responsible for the generation of trailing edge noise. The TILS (turbulence integral length scale) of the turbulent wake...The turbulent wakes behind trailing edge are analyzed for understanding of the flow mechanisms responsible for the generation of trailing edge noise. The TILS (turbulence integral length scale) of the turbulent wake of hydrofoil with blunt trailing edge is calculated from TR-PIV (time-resolved particle image velocimetry) data. The temporal auto-correlation method based on Taylor hypothesis and spatial correlation method are used to get the TILS information of the turbulent wake of hydrofoil, respectively The comparison of results by two methods indicates that the spatial correlation method is independent on Taylor hypothesis and suitable to strong turbulence and non-isotropic turbulence.展开更多
Simultaneous measurements from THEMIS spacecraft, GOES11 and ground stations (Canadian Array for Realtime Investiga tions of Magnetic Activity or CARISMA, and 210 magnetic meridian or MM) on March 18, 2009 allow the...Simultaneous measurements from THEMIS spacecraft, GOES11 and ground stations (Canadian Array for Realtime Investiga tions of Magnetic Activity or CARISMA, and 210 magnetic meridian or MM) on March 18, 2009 allow the study of dynamic processes in the nearEarth magnetotail and corresponding Pi2 pulsations on the ground in great detail. Fast earthward flows along with traveling Alfv6n waves and fast mode waves in the Pi2 band were observed by three Time History of Events and Macroscale Interactions during Substorms (THEM/S) probes (P3, P4 and P5) in the nearEarth plasmasbeet. At the mid to highlatitude nightside, the CARISMA stations located near the foot points of the three probes recorded Pi2s with two periods, about 80 s after the earthward fast flows observed by the P4 probe. The longperiod Pi2 (140-150 s) belongs to the transient response Pi2 (TR Pi2), since the travel time of the Alfv6n waves between the plasma sheet and CARISMA stations is very close to half the period of the longperiod Pi2. The shortperiod Pi2 (60-80 s) has the same period band as the perpendicular velocity of the fast flows, which indicates that it may relate to the inertial current caused by periodic braking of the earthward fast flows. The 210 MM stations located at the lowlatitude duskside also observed Pi2s with the same start time, waveform and frequency, about 120 s after the earthward fast flows. Strong poloidal oscillations are shown by GOES11 (23 MLT) and the compressional component (Bb) is highly correlated with H components of the 210 MM stations, whereas the other two components (Br and Be) are not. These results confirm that the lowlatitude Pi2s are generated by cavity mode resonance, which is driven by an impulsive broadband source in the nearEarth magnetotail.展开更多
Using Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations from 2007 to 2011 tail seasons, we study the plasma properties of high speed flows (HSFs) and background plasma sheet...Using Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations from 2007 to 2011 tail seasons, we study the plasma properties of high speed flows (HSFs) and background plasma sheet events (BPSs) in Earth's magnetotail (|YGsM|〈13RE, |ZGsM|〈5RE, -30RE〈XrsM〈-6RE), and their correlations with solar wind parameters. Statistical results show that the closer the HSFs and BPSs are to the Earth, the hotter they become, and the temperature increase of HSFs is larger than that of BPSs. The density and temperature ratios between HSFs and BPSs are also larger when events are closer to Earth. We also find that the best correlations between the HSFs (BPSs) density and the solar wind density occur when the solar wind density is averaged 2 (3.5) hours prior to the onset of HSFs (BPSs). The normalized densities of both HSFs and BPSs are correlated with the interplanetary magnetic field (IMF) 0 angles ( 0 = arctan(Bz √Bx^2+y^2 ) which are averaged 3 hours before the observation time. Further analysis indicates that both HSFs and BPSs become denser during the northward IMF period.展开更多
Particle Imaging Velocimetry (PIV) is utilized to investigate the flow structures of an oscillating cylinder attached to a flexible tail. At the same oscillation frequency and amplitude, the mean streamwise velocity...Particle Imaging Velocimetry (PIV) is utilized to investigate the flow structures of an oscillating cylinder attached to a flexible tail. At the same oscillation frequency and amplitude, the mean streamwise velocity along the wake central-line and the mean vertical velocity around the trailing edge of the flexible tail can be greatly increased with the tail length. Meanwhile, the longer the flexible tail is, the larger its deformation is. In order to study the influence of flexible tail length on the wake pattern of the experimental model, the relationships between the swirling strength Aci of vortex structure near the tail end and the velocity of tail trailing edge have been revealed. Moreover, the convection tracks and the Aci of vortex cores for different flexible tails are discussed.展开更多
Based on the magnetic field and plasma data obtained by GEOTAIL in 1992-1995 and WIND in1994-2009, the magnetic field and plasma properties in the magnetotail near lunar orbit were studied statistically using the supe...Based on the magnetic field and plasma data obtained by GEOTAIL in 1992-1995 and WIND in1994-2009, the magnetic field and plasma properties in the magnetotail near lunar orbit were studied statistically using the superposed epoch analysis. The results showed that near the 0° sector the plasma density was negatively correlated with Dst index while the temperature was positively correlated with Dst index. The plasma velocity and magnetic field strength had little correlation with Dst index. Around the current sheet near the lunar orbit, the Bx varied between -15-15 nT, the plasma density was less than 0.4 cm^-3, the median of plasma density for all events was less than 0.1 cm^-3, the temperature varied from 0.016 to 8.98 keV, the median of the plasma temperature for all the events was -3 keV, the median of speed was about 200 km/s and the maximum speed was up to 1500 km/s. The tailward and earthward flows could be observed accompanied with the current sheet. For the current sheet cases with tailward flow, the Bx varied from -15 to 15 nT, the upper quartile of plasma velocity was more than 400 krn/s, the maximum speed was up to 1500 km/s. For the current sheet cases with tailward flow, the Bx varied from -10 to 10 nT, the upper quartile of plasma velocity was less than 400 km/s, the maximum speed was up to 1200 km/s. The median of plasma density, temperature and velocity were similar for the two categories. This paper discussed the relationship between above results and magnetic reconnection at magnetic tail, compared the above results with the observation in the far magnetotail. We fitted the statistical results according to the Harris current sheet model, and the observation was consistent with Harris current sheet model. The above results can provide useful information for the design and protection of lunar-orbiting spacecraft and can be used as the background magnetic field and plasma parameters in the numerical simulation of mid-magnetotail reconnection.展开更多
基金Projects(41073060,21007009)supported by the National Natural Science Foundation of China"Chen Guang" project(10CG34)supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation,ChinaProjects(20100075120010,20100075110010)supported by Research Fund for the Doctoral Program of Higher Education of China
文摘AThe wastewater source of 4# tailing pond in Dexing copper mine consists of alkaline flotation pulp and acid mine drainage (AMD) from the nearby opencast mine. Therefore, the heavy metals in tailing ore are very likely to be released due to acidification from AMD. The leaching behaviors ofZn, Cu, Fe and Mn in mine tailings from Dexing copper mine were investigated by a series of laboratory batch experiments. The effectcs ofpH, temperature, particle size and contact time on the leachability of such heavy metals were examined. It was evident that Zn, Cu, Fe and Mn were major heavy metals in the tailings while gangue minerals like quartz were major constituents in examined tailings. The tailing dissolution reaction was controlled by the acid, whose kinetics could be expressed according to the heterogeneous reaction models and explained by a shrinking core model with the surface chemical reaction as the rate-controlling step. The leachability of all metals examined depended on pH and contact time. The batch studies indicated that the maximum leaching ratios ofZn, Cu, Fe and Mn at pH 2.0 were 5.4%, 5.8%, l 1.1% and 34.1%, respectively. The dissolubility of all metals examined was positively correlated to the temperatures. The particle size would not change dissolution tendency of those heavy metals, but decrease the concentrations of leached heavy metals.
基金sponsored by the 973 Program of China(No.2013CB228604)the Natural Science Foundation of Shandong Province(No.ZR2013DQ020)+1 种基金the Fundamental Research Funds for the Central Universities(No.15CX08002A)the National Natural Science Foundation of China(No.41374123)
文摘Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the first arrivals. Hence, first arrivals cannot be used to detect small seismic velocity variations. However, small variations can be reliably detected by the coda waves because of the amplification owing to multiple scattering. We investigate the ability of coda wave interferometry to detect seismic velocity variations and monitor time-lapse reservoir characteristics using numerical simulations and experimental data. We use the Marmousi II model and finite-difference methods to build model seismic data and introduce small seismic velocity variations in the target layer. We examine the model seismic data before and after the changes and observe the coda waves. We find that velocity changes can be detected by coda wave interferometry and demonstrate that coda wave interferometry can be used in monitoring time- lapse reservoir characteristics.
文摘The turbulent wakes behind trailing edge are analyzed for understanding of the flow mechanisms responsible for the generation of trailing edge noise. The TILS (turbulence integral length scale) of the turbulent wake of hydrofoil with blunt trailing edge is calculated from TR-PIV (time-resolved particle image velocimetry) data. The temporal auto-correlation method based on Taylor hypothesis and spatial correlation method are used to get the TILS information of the turbulent wake of hydrofoil, respectively The comparison of results by two methods indicates that the spatial correlation method is independent on Taylor hypothesis and suitable to strong turbulence and non-isotropic turbulence.
基金supported by the National Key Basic Research Program of China (Grant No.2012CB825604)the National Natural Science Foundation of China (Grant Nos.41104093 & 41204122).
文摘Simultaneous measurements from THEMIS spacecraft, GOES11 and ground stations (Canadian Array for Realtime Investiga tions of Magnetic Activity or CARISMA, and 210 magnetic meridian or MM) on March 18, 2009 allow the study of dynamic processes in the nearEarth magnetotail and corresponding Pi2 pulsations on the ground in great detail. Fast earthward flows along with traveling Alfv6n waves and fast mode waves in the Pi2 band were observed by three Time History of Events and Macroscale Interactions during Substorms (THEM/S) probes (P3, P4 and P5) in the nearEarth plasmasbeet. At the mid to highlatitude nightside, the CARISMA stations located near the foot points of the three probes recorded Pi2s with two periods, about 80 s after the earthward fast flows observed by the P4 probe. The longperiod Pi2 (140-150 s) belongs to the transient response Pi2 (TR Pi2), since the travel time of the Alfv6n waves between the plasma sheet and CARISMA stations is very close to half the period of the longperiod Pi2. The shortperiod Pi2 (60-80 s) has the same period band as the perpendicular velocity of the fast flows, which indicates that it may relate to the inertial current caused by periodic braking of the earthward fast flows. The 210 MM stations located at the lowlatitude duskside also observed Pi2s with the same start time, waveform and frequency, about 120 s after the earthward fast flows. Strong poloidal oscillations are shown by GOES11 (23 MLT) and the compressional component (Bb) is highly correlated with H components of the 210 MM stations, whereas the other two components (Br and Be) are not. These results confirm that the lowlatitude Pi2s are generated by cavity mode resonance, which is driven by an impulsive broadband source in the nearEarth magnetotail.
基金National Natural Science Foundation of China (Grant Nos. 41322031, 41031065 & 41574157)the Shandong Province Outstanding Young Scientist Award (Grant No. 2013BSE27132)+2 种基金the Research Fund for the Doctoral Program of Higher Education (Grant No. 20130131120073)the program for New Century Excellent Talents in University (Grant No. NCET-12-0332)State Key Laboratories of Space Weather
文摘Using Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations from 2007 to 2011 tail seasons, we study the plasma properties of high speed flows (HSFs) and background plasma sheet events (BPSs) in Earth's magnetotail (|YGsM|〈13RE, |ZGsM|〈5RE, -30RE〈XrsM〈-6RE), and their correlations with solar wind parameters. Statistical results show that the closer the HSFs and BPSs are to the Earth, the hotter they become, and the temperature increase of HSFs is larger than that of BPSs. The density and temperature ratios between HSFs and BPSs are also larger when events are closer to Earth. We also find that the best correlations between the HSFs (BPSs) density and the solar wind density occur when the solar wind density is averaged 2 (3.5) hours prior to the onset of HSFs (BPSs). The normalized densities of both HSFs and BPSs are correlated with the interplanetary magnetic field (IMF) 0 angles ( 0 = arctan(Bz √Bx^2+y^2 ) which are averaged 3 hours before the observation time. Further analysis indicates that both HSFs and BPSs become denser during the northward IMF period.
基金supported by the National Natural Science Foundation of China (Grant No. 10832001)the Innovation Foundation of BUAA for PhD Graduates
文摘Particle Imaging Velocimetry (PIV) is utilized to investigate the flow structures of an oscillating cylinder attached to a flexible tail. At the same oscillation frequency and amplitude, the mean streamwise velocity along the wake central-line and the mean vertical velocity around the trailing edge of the flexible tail can be greatly increased with the tail length. Meanwhile, the longer the flexible tail is, the larger its deformation is. In order to study the influence of flexible tail length on the wake pattern of the experimental model, the relationships between the swirling strength Aci of vortex structure near the tail end and the velocity of tail trailing edge have been revealed. Moreover, the convection tracks and the Aci of vortex cores for different flexible tails are discussed.
基金supported by the National Natural Science Foundation ofChina (Grant No. 40831061)the National Key Laboratory Special Fund and the Open Research Foundation of Science and Technology on Aerospace Flight Dynamics Laboratory (Grant No. 2012afd1034)
文摘Based on the magnetic field and plasma data obtained by GEOTAIL in 1992-1995 and WIND in1994-2009, the magnetic field and plasma properties in the magnetotail near lunar orbit were studied statistically using the superposed epoch analysis. The results showed that near the 0° sector the plasma density was negatively correlated with Dst index while the temperature was positively correlated with Dst index. The plasma velocity and magnetic field strength had little correlation with Dst index. Around the current sheet near the lunar orbit, the Bx varied between -15-15 nT, the plasma density was less than 0.4 cm^-3, the median of plasma density for all events was less than 0.1 cm^-3, the temperature varied from 0.016 to 8.98 keV, the median of the plasma temperature for all the events was -3 keV, the median of speed was about 200 km/s and the maximum speed was up to 1500 km/s. The tailward and earthward flows could be observed accompanied with the current sheet. For the current sheet cases with tailward flow, the Bx varied from -15 to 15 nT, the upper quartile of plasma velocity was more than 400 krn/s, the maximum speed was up to 1500 km/s. For the current sheet cases with tailward flow, the Bx varied from -10 to 10 nT, the upper quartile of plasma velocity was less than 400 km/s, the maximum speed was up to 1200 km/s. The median of plasma density, temperature and velocity were similar for the two categories. This paper discussed the relationship between above results and magnetic reconnection at magnetic tail, compared the above results with the observation in the far magnetotail. We fitted the statistical results according to the Harris current sheet model, and the observation was consistent with Harris current sheet model. The above results can provide useful information for the design and protection of lunar-orbiting spacecraft and can be used as the background magnetic field and plasma parameters in the numerical simulation of mid-magnetotail reconnection.