Based on the observational data analyses and numerical simulations with the air-sea coupled model (CGCM), a new perspective on the occurrence mechanism of ENSO is advanced in this paper. The continuous strong (weak) E...Based on the observational data analyses and numerical simulations with the air-sea coupled model (CGCM), a new perspective on the occurrence mechanism of ENSO is advanced in this paper. The continuous strong (weak) East Asian winter monsoon will lead to continuous westerly (easterly) wind anomalies over the equatorial western Pacific region. The anomalous equatorial westerly (easterly) winds can cause eastward propagation of the subsurface ocean temperature anomalies (SOTA) in the warm pool region, the positive (negative) SOTA have been in the warm pool region for quite a long time. The eastward propagating of positive (negative) SOTA along the thermocline will lead to positive (negative) SSTA in the equatorial eastern Pacific and the occurrence of El Nino (La Nina) event. After the occurrence of ENSO, the winter monsoon in East Asia will be weak (strong) due to the influence of El Nino (La Nina).展开更多
The variation of warm pool ocean temperature in the equatorial western Pacific and its impacts on climatic change are studied in the present paper. The SSTs in the warm pool region not only have seasonal variation but...The variation of warm pool ocean temperature in the equatorial western Pacific and its impacts on climatic change are studied in the present paper. The SSTs in the warm pool region not only have seasonal variation but also have interannual variation more clearly; The influence of anomalies of SST in the warm pool region on the East Asian monsoon is studied with data analysis; And the impact of SSTA in the warm pool region on the teleconnection (wave-train) in the atmospheric circulation is still investigated. The influence of ocean temperature anomalies in the warm pool subsurface on the occurrence of ENSO is also discussed by using data analysis and modelling with CGCM. All above-mentioned studies show that the situation of ocean temperature in the warm pool region in the equatorial western Pacific plays an important role in the global climatic variation.展开更多
The safe and efficient operation of the electric vehicle significantly depends on the accurate state-of-charge(SOC)and state-of-temperature(SOT)of Lithium-ion(Li-ion)batteries.Given the influence of cross-interference...The safe and efficient operation of the electric vehicle significantly depends on the accurate state-of-charge(SOC)and state-of-temperature(SOT)of Lithium-ion(Li-ion)batteries.Given the influence of cross-interference between the two states indicated above,this study establishs a co-estimation framework of battery SOC and SOT.This framwork is based on an innovative electrothermal model and adaptive estimation algorithms.The first-order RC electric model and an innovative thermal model are components of the electrothermal model.Specifically,the thermal model includes two lumped-mass thermal submodels for two tabs and a two-dimensional(2-D)thermal resistance network(TRN)submodel for the main battery body,capable of capturing the detailed thermodynamics of large-format Li-ion batteries.Moreover,the proposed thermal model strikes an acceptable compromise between the estimation fidelity and computational complexity by representing the heat transfer processes by the thermal resistances.Besides,the adaptive estimation algorithms are composed of an adaptive unscented Kalman filter(AUKF)and an adaptive Kalman filter(AKF),which adaptively update the state and noise covariances.Regarding the estimation results,the mean absolute errors(MAEs)of SOC and SOT estimation are controlled within 1%and 0.4°C at two temperatures,indicating that the co-estimation method yields superior prediction performance in a wide temperature range of 5–35°C.展开更多
Clustering is the most significant task characterized in Wireless Sensor Networks (WSN) by data aggregation through each Cluster Head (CH). This leads to the reduction in the traffic cost. Due to the deployment of the...Clustering is the most significant task characterized in Wireless Sensor Networks (WSN) by data aggregation through each Cluster Head (CH). This leads to the reduction in the traffic cost. Due to the deployment of the WSN in the remote and hostile environments for the transmission of the sensitive information, the sensor nodes are more prone to the false data injection attacks. To overcome these existing issues and enhance the network security, this paper proposes a Secure Area based Clustering approach for data aggregation using Traffic Analysis (SAC-TA) in WSN. Here, the sensor network is clustered into small clusters, such that each cluster has a CH to manage and gather the information from the normal sensor nodes. The CH is selected based on the predefined time slot, cluster center, and highest residual energy. The gathered data are validated based on the traffic analysis and One-time Key Generation procedures to identify the malicious nodes on the route. It helps to provide a secure data gathering process with improved energy efficiency. The performance of the proposed approach is compared with the existing Secure Data Aggregation Technique (SDAT). The proposed SAC-TA yields lower average energy consumption rate, lower end-to-end delay, higher average residual energy, higher data aggregation accuracy and false data detection rate than the existing technique.展开更多
选取2015—2018年影响华东地区的13个台风个例,分析降水极端天气指数EFI(Extreme Forecast Index)和SOT(Shift of Tails)与台风降水之间的统计关系。结果表明:EFI和SOT与降水气候百分位之间存在明显的正相关关系。EFI和SOT越大,强降水...选取2015—2018年影响华东地区的13个台风个例,分析降水极端天气指数EFI(Extreme Forecast Index)和SOT(Shift of Tails)与台风降水之间的统计关系。结果表明:EFI和SOT与降水气候百分位之间存在明显的正相关关系。EFI和SOT越大,强降水发生概率越高。随着预报时效的增加,EFI和SOT指数对暴雨和大暴雨的预报效果逐渐变差。对于短期(72 h以内的时效),EFI预报技巧优于SOT,而随着预报时效的延长,SOT的预报技巧逐渐接近并超过EFI。以TS评分最大为标准兼顾合理的预报偏差,得到两种极端天气指数不同预报时效、不同等级暴雨的预报阈值。总体而言,事件越极端,EFI和SOT的预报阈值越大,对于暴雨和大暴雨,EFI指数的预报阈值随着预报时效的延长有减小趋势,而SOT的预报阈值基本保持不变。在台风极端降水预报中,EFI和SOT可以作为EC定量降水预报的补充,有助于减少强降水的漏报,并提早发出预警信息。展开更多
We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured u...We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured uniformly by the 200-mm-wafer platform.The performance of the devices is systematically studied,including their magnetic properties,switch-ing behaviors,endurance and data retention.The successful integration of SOT devices within the 200-mm-wafer manufactur-ing platform provides a feasible way to industrialize SOT MRAMs.It is expected to obtain excellent performance of the devices by further optimizing the MTJ film stacks and the corresponding fabrication processes in the future.展开更多
文摘Based on the observational data analyses and numerical simulations with the air-sea coupled model (CGCM), a new perspective on the occurrence mechanism of ENSO is advanced in this paper. The continuous strong (weak) East Asian winter monsoon will lead to continuous westerly (easterly) wind anomalies over the equatorial western Pacific region. The anomalous equatorial westerly (easterly) winds can cause eastward propagation of the subsurface ocean temperature anomalies (SOTA) in the warm pool region, the positive (negative) SOTA have been in the warm pool region for quite a long time. The eastward propagating of positive (negative) SOTA along the thermocline will lead to positive (negative) SSTA in the equatorial eastern Pacific and the occurrence of El Nino (La Nina) event. After the occurrence of ENSO, the winter monsoon in East Asia will be weak (strong) due to the influence of El Nino (La Nina).
文摘The variation of warm pool ocean temperature in the equatorial western Pacific and its impacts on climatic change are studied in the present paper. The SSTs in the warm pool region not only have seasonal variation but also have interannual variation more clearly; The influence of anomalies of SST in the warm pool region on the East Asian monsoon is studied with data analysis; And the impact of SSTA in the warm pool region on the teleconnection (wave-train) in the atmospheric circulation is still investigated. The influence of ocean temperature anomalies in the warm pool subsurface on the occurrence of ENSO is also discussed by using data analysis and modelling with CGCM. All above-mentioned studies show that the situation of ocean temperature in the warm pool region in the equatorial western Pacific plays an important role in the global climatic variation.
基金National Natural Science Foundation of China(NSFC,Grant No.52107230)Fundamental Research Funds for the Central Universities and the Major State Basic Research Development Program of China。
文摘The safe and efficient operation of the electric vehicle significantly depends on the accurate state-of-charge(SOC)and state-of-temperature(SOT)of Lithium-ion(Li-ion)batteries.Given the influence of cross-interference between the two states indicated above,this study establishs a co-estimation framework of battery SOC and SOT.This framwork is based on an innovative electrothermal model and adaptive estimation algorithms.The first-order RC electric model and an innovative thermal model are components of the electrothermal model.Specifically,the thermal model includes two lumped-mass thermal submodels for two tabs and a two-dimensional(2-D)thermal resistance network(TRN)submodel for the main battery body,capable of capturing the detailed thermodynamics of large-format Li-ion batteries.Moreover,the proposed thermal model strikes an acceptable compromise between the estimation fidelity and computational complexity by representing the heat transfer processes by the thermal resistances.Besides,the adaptive estimation algorithms are composed of an adaptive unscented Kalman filter(AUKF)and an adaptive Kalman filter(AKF),which adaptively update the state and noise covariances.Regarding the estimation results,the mean absolute errors(MAEs)of SOC and SOT estimation are controlled within 1%and 0.4°C at two temperatures,indicating that the co-estimation method yields superior prediction performance in a wide temperature range of 5–35°C.
文摘Clustering is the most significant task characterized in Wireless Sensor Networks (WSN) by data aggregation through each Cluster Head (CH). This leads to the reduction in the traffic cost. Due to the deployment of the WSN in the remote and hostile environments for the transmission of the sensitive information, the sensor nodes are more prone to the false data injection attacks. To overcome these existing issues and enhance the network security, this paper proposes a Secure Area based Clustering approach for data aggregation using Traffic Analysis (SAC-TA) in WSN. Here, the sensor network is clustered into small clusters, such that each cluster has a CH to manage and gather the information from the normal sensor nodes. The CH is selected based on the predefined time slot, cluster center, and highest residual energy. The gathered data are validated based on the traffic analysis and One-time Key Generation procedures to identify the malicious nodes on the route. It helps to provide a secure data gathering process with improved energy efficiency. The performance of the proposed approach is compared with the existing Secure Data Aggregation Technique (SDAT). The proposed SAC-TA yields lower average energy consumption rate, lower end-to-end delay, higher average residual energy, higher data aggregation accuracy and false data detection rate than the existing technique.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFB3601303,2021YFB3601304,2021YFB3601300)National Natural Science Foundation of China(Nos.62001014 and 62171013)。
文摘We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured uniformly by the 200-mm-wafer platform.The performance of the devices is systematically studied,including their magnetic properties,switch-ing behaviors,endurance and data retention.The successful integration of SOT devices within the 200-mm-wafer manufactur-ing platform provides a feasible way to industrialize SOT MRAMs.It is expected to obtain excellent performance of the devices by further optimizing the MTJ film stacks and the corresponding fabrication processes in the future.
