A disk-corona model for fitting the low/hard(LH)state of the associated steady jet in black hole X-ray binaries(BHXBs)is proposed based on the large-scale magnetic field configuration that arises from the coexiste...A disk-corona model for fitting the low/hard(LH)state of the associated steady jet in black hole X-ray binaries(BHXBs)is proposed based on the large-scale magnetic field configuration that arises from the coexistence of the Blandford-Znajek(BZ)and Blandford-Payne(BP)processes,where the magnetic field configuration for the BP process is determined by the requirement of energy conversion from Poynting energy flux into kinetic energy flux in the jet.It is found that corona current is crucial to guarantee the consistency of the jet launching from the accretion disk.The relative importance of the BZ and BP processes in powering jets from black hole accretion disks is discussed,and the LH state of several BHXBs is fitted based on our model.In addition,we suggest that magnetic field configuration can be regarded as the second parameter for governing the state transition of BHXBs.展开更多
A numerical model of thermoelectric module (TEM) is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyz...A numerical model of thermoelectric module (TEM) is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyzed by the MATLAB numerical calculation.The numerical model is validated by the ANSYS thermal,electrical,and structural coupling simulation.The effects of the variable physical property parameters and contact effect on the output power and thermoelectric efficiency are evaluated,and the concept of aspect ratio optimal domain is proposed,which provides a new design approach for the TEM.展开更多
Static security assessment(SSA) is an important procedure to ensure the static security of the power system.Researches recently show that cyber-attacks might be a critical hazard to the secure and economic operations ...Static security assessment(SSA) is an important procedure to ensure the static security of the power system.Researches recently show that cyber-attacks might be a critical hazard to the secure and economic operations of the power system. In this paper, the influences of false data injection attack(FDIA) on the power system SSA are studied. FDIA is a major kind of cyber-attacks that can inject malicious data into meters, cause false state estimation results, and evade being detected by bad data detection. It is firstly shown that the SSA results could be manipulated by launching a successful FDIA, which can lead to incorrect or unnecessary corrective actions. Then,two kinds of targeted scenarios are proposed, i.e., fake secure signal attack and fake insecure signal attack. The former attack will deceive the system operator to believe that the system operates in a secure condition when it is actually not. The latter attack will deceive the system operator to make corrective actions, such as generator rescheduling, load shedding, etc. when it is unnecessary and costly. The implementation of the proposed analysis is validated with the IEEE-39 benchmark system.展开更多
基金Supported by the National Natural Science Foundation of China (No. 11173011)the National Basic Research Program of China (973 Program, No. 2009CB824800)
文摘A disk-corona model for fitting the low/hard(LH)state of the associated steady jet in black hole X-ray binaries(BHXBs)is proposed based on the large-scale magnetic field configuration that arises from the coexistence of the Blandford-Znajek(BZ)and Blandford-Payne(BP)processes,where the magnetic field configuration for the BP process is determined by the requirement of energy conversion from Poynting energy flux into kinetic energy flux in the jet.It is found that corona current is crucial to guarantee the consistency of the jet launching from the accretion disk.The relative importance of the BZ and BP processes in powering jets from black hole accretion disks is discussed,and the LH state of several BHXBs is fitted based on our model.In addition,we suggest that magnetic field configuration can be regarded as the second parameter for governing the state transition of BHXBs.
基金Funded by Guangdong Natural Science Foundation (No.00355991220615019)
文摘A numerical model of thermoelectric module (TEM) is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyzed by the MATLAB numerical calculation.The numerical model is validated by the ANSYS thermal,electrical,and structural coupling simulation.The effects of the variable physical property parameters and contact effect on the output power and thermoelectric efficiency are evaluated,and the concept of aspect ratio optimal domain is proposed,which provides a new design approach for the TEM.
基金supported by the Hong Kong Polytechnic University(1-YW1Q)
文摘Static security assessment(SSA) is an important procedure to ensure the static security of the power system.Researches recently show that cyber-attacks might be a critical hazard to the secure and economic operations of the power system. In this paper, the influences of false data injection attack(FDIA) on the power system SSA are studied. FDIA is a major kind of cyber-attacks that can inject malicious data into meters, cause false state estimation results, and evade being detected by bad data detection. It is firstly shown that the SSA results could be manipulated by launching a successful FDIA, which can lead to incorrect or unnecessary corrective actions. Then,two kinds of targeted scenarios are proposed, i.e., fake secure signal attack and fake insecure signal attack. The former attack will deceive the system operator to believe that the system operates in a secure condition when it is actually not. The latter attack will deceive the system operator to make corrective actions, such as generator rescheduling, load shedding, etc. when it is unnecessary and costly. The implementation of the proposed analysis is validated with the IEEE-39 benchmark system.