The determination of channel evolutions and the causes is important for reconstructing the evolutionary history of river landforms.This study aimed to elucidate the downstream channel evolution of the Yuan River in Hu...The determination of channel evolutions and the causes is important for reconstructing the evolutionary history of river landforms.This study aimed to elucidate the downstream channel evolution of the Yuan River in Hunan Province,China,during the Qing Dynasty via Landsat 8 satellite image data and relevant literature.The objective was to establish the modes of channel evolution and discuss the significance of historical climate change.The downstream paleochannel of the Yuan River was identified in the Late Ming Dynasty and Early Qing Dynasty(1600–1644 AD),the Kangxi-Qianlong periods of the Qing Dynasty(1661–1796 AD),the Late Qing Dynasty(1840–1912 AD),and the World War II(1939–1945 AD),and three main modes of river evolution were determined.Using remote sensing data and the ancient literature,the evolution characteristics of the paleochannel in the Lower Yuan River were analyzed and its distribution across historical periods was comprehensively revealed.The findings reveal a strong correlation between channel evolution,flood events,and climate change.Numerous flood events that occurred from the Late Qing Dynasty to the World War II caused a high rate of channel evolution,demonstrating the combined effects of climate change and human activities.These findings will help adopt robust and resilient hydrological management methods in the future of a changing climate.展开更多
A rarely reported middle-late Miocene-Pliocene channel(incised valley fill),the Huaguang Channel(HGC),has been found in the deep-water area of the southwestern Qiongdongnan Basin(QDNB).This channel is almost perpendic...A rarely reported middle-late Miocene-Pliocene channel(incised valley fill),the Huaguang Channel(HGC),has been found in the deep-water area of the southwestern Qiongdongnan Basin(QDNB).This channel is almost perpendicular to the orientation of another well-known,large,and nearly coeval submarine channel in this area.Based on the interpretation of high-resolution 3D seismic data,this study describes and analyzes the stratigraphy,tectonics,sedimentation,morphology,structure and evolution of HGC by means of well-seismic synthetic calibration,one-and two-dimensional forward modeling,attribute interpretation,tectonic interpretation,and gas detection.The HGC is located on the downthrown side of an earlier activated normal fault and grew northwestward along the fault strike.The channel is part of a slope that extends from the western Huaguang Sag to the eastern Beijiao Uplift.The HGC underwent four developmental stages:the(1)incubation(late Sanya Formation,20.4–15.5 Ma),(2)embryonic(Meishan Formation,15.5–10.5 Ma),(3)peak(Huangliu Formation,10.5–5.5 Ma)and(4)decline(Yinggehai Formation,5.5–1.9 Ma)stages.The channel sandstones have a provenance from the southern Yongle Uplift and filled the channel via multistage vertical amalgamation and lateral migration.The channel extended 42.5 km in an approximately straight pattern in the peak stage.At 10.5 Ma,sea level fell relative to its lowest level,and three oblique progradation turbidite sand bodies filled the channel from south to north.A channel sandstone isopach map demonstrated a narrow distribution in the early stages and a fan-shaped distribution in the late stage.The formation and evolution of the HGC were controlled mainly by background tectonics,fault strike,relative sea level change,and mass supply from the Yongle Uplift.The HGC sandstone reservoir is near the Huaguangjiao Sag,where hydrocarbons were generated.Channel-bounding faults and underlying faults link the source rock with the reservoir.A regionally extensive mudstone caprock overlies the channel sandstone.Two traps likely containing gas were recognized in a structural high upstream of the channel from seismic attenuation anomalies.The HGC will likely become an important oil and gas accumulation setting in the QDNB deep-water area.展开更多
A multiple-input multiple-output interleave division multiple access (MIMO-IDMA) system with Triple Polarized Division Multiplexing (TPDM) is presented in this paper. The present methodology replaces three indepe...A multiple-input multiple-output interleave division multiple access (MIMO-IDMA) system with Triple Polarized Division Multiplexing (TPDM) is presented in this paper. The present methodology replaces three independent linearly polarized antennas with a single triple polarized antenna at both the transmitter and receiver. The users in the communication link are accommodated and separated using a user-specific interleaver combined with low rate spreading sequence. To eliminate the effects of multi-stream interference (MSI), minimum mean square error (MMSE) algorithm based on successive interference cancellation (SIC) Multi-user detection (MUD) technique is employed at the receiver. Furthermore, log-maximum a posteriori probability (MAPP) decoding algorithm is implemented at the mobile stations (MSs) to overcome the effects of multi-user interference (MUI) effects. The paper also evaluates the effects of coded MIMO-IDMA in the downlink communication by adopting the Stanford University Interim (SUI) and Long-term Evolution (LTE)channel model specifications. In comparison with the traditional uncoded system, the present solution considering turbo coded triple-polarized MIMO-IDMA system with iterative decoding algorithm provides better bit error rate (BER) with reduced signal to noise ratio (SNR). The simulation results also show that though the SNR requirement is higher for the proposed technique compared to the conventional uni-polarized antenna based MIMO-IDMA system, it gives the advantages of achieving higher data rate with reduced cost and space requirements in the context of a downlink (DL).展开更多
文摘The determination of channel evolutions and the causes is important for reconstructing the evolutionary history of river landforms.This study aimed to elucidate the downstream channel evolution of the Yuan River in Hunan Province,China,during the Qing Dynasty via Landsat 8 satellite image data and relevant literature.The objective was to establish the modes of channel evolution and discuss the significance of historical climate change.The downstream paleochannel of the Yuan River was identified in the Late Ming Dynasty and Early Qing Dynasty(1600–1644 AD),the Kangxi-Qianlong periods of the Qing Dynasty(1661–1796 AD),the Late Qing Dynasty(1840–1912 AD),and the World War II(1939–1945 AD),and three main modes of river evolution were determined.Using remote sensing data and the ancient literature,the evolution characteristics of the paleochannel in the Lower Yuan River were analyzed and its distribution across historical periods was comprehensively revealed.The findings reveal a strong correlation between channel evolution,flood events,and climate change.Numerous flood events that occurred from the Late Qing Dynasty to the World War II caused a high rate of channel evolution,demonstrating the combined effects of climate change and human activities.These findings will help adopt robust and resilient hydrological management methods in the future of a changing climate.
基金The National Natural Science Foundation of China’s Major Project “Research on Geophysical Theories and Methods of Unconventional Oil and Gas Exploration and Development”, Task Ⅰ: “China’s Tight Oil and Gas Reservoir Geological Characteristics, Classification and Typical Geological Model Establishment” under contract No. 41390451the Science and Technology Project of Sinopec Shanghai Offshore Petroleum Company under contract No. KJ-2021-7
文摘A rarely reported middle-late Miocene-Pliocene channel(incised valley fill),the Huaguang Channel(HGC),has been found in the deep-water area of the southwestern Qiongdongnan Basin(QDNB).This channel is almost perpendicular to the orientation of another well-known,large,and nearly coeval submarine channel in this area.Based on the interpretation of high-resolution 3D seismic data,this study describes and analyzes the stratigraphy,tectonics,sedimentation,morphology,structure and evolution of HGC by means of well-seismic synthetic calibration,one-and two-dimensional forward modeling,attribute interpretation,tectonic interpretation,and gas detection.The HGC is located on the downthrown side of an earlier activated normal fault and grew northwestward along the fault strike.The channel is part of a slope that extends from the western Huaguang Sag to the eastern Beijiao Uplift.The HGC underwent four developmental stages:the(1)incubation(late Sanya Formation,20.4–15.5 Ma),(2)embryonic(Meishan Formation,15.5–10.5 Ma),(3)peak(Huangliu Formation,10.5–5.5 Ma)and(4)decline(Yinggehai Formation,5.5–1.9 Ma)stages.The channel sandstones have a provenance from the southern Yongle Uplift and filled the channel via multistage vertical amalgamation and lateral migration.The channel extended 42.5 km in an approximately straight pattern in the peak stage.At 10.5 Ma,sea level fell relative to its lowest level,and three oblique progradation turbidite sand bodies filled the channel from south to north.A channel sandstone isopach map demonstrated a narrow distribution in the early stages and a fan-shaped distribution in the late stage.The formation and evolution of the HGC were controlled mainly by background tectonics,fault strike,relative sea level change,and mass supply from the Yongle Uplift.The HGC sandstone reservoir is near the Huaguangjiao Sag,where hydrocarbons were generated.Channel-bounding faults and underlying faults link the source rock with the reservoir.A regionally extensive mudstone caprock overlies the channel sandstone.Two traps likely containing gas were recognized in a structural high upstream of the channel from seismic attenuation anomalies.The HGC will likely become an important oil and gas accumulation setting in the QDNB deep-water area.
文摘A multiple-input multiple-output interleave division multiple access (MIMO-IDMA) system with Triple Polarized Division Multiplexing (TPDM) is presented in this paper. The present methodology replaces three independent linearly polarized antennas with a single triple polarized antenna at both the transmitter and receiver. The users in the communication link are accommodated and separated using a user-specific interleaver combined with low rate spreading sequence. To eliminate the effects of multi-stream interference (MSI), minimum mean square error (MMSE) algorithm based on successive interference cancellation (SIC) Multi-user detection (MUD) technique is employed at the receiver. Furthermore, log-maximum a posteriori probability (MAPP) decoding algorithm is implemented at the mobile stations (MSs) to overcome the effects of multi-user interference (MUI) effects. The paper also evaluates the effects of coded MIMO-IDMA in the downlink communication by adopting the Stanford University Interim (SUI) and Long-term Evolution (LTE)channel model specifications. In comparison with the traditional uncoded system, the present solution considering turbo coded triple-polarized MIMO-IDMA system with iterative decoding algorithm provides better bit error rate (BER) with reduced signal to noise ratio (SNR). The simulation results also show that though the SNR requirement is higher for the proposed technique compared to the conventional uni-polarized antenna based MIMO-IDMA system, it gives the advantages of achieving higher data rate with reduced cost and space requirements in the context of a downlink (DL).
