Using the first-principles calculations,we study the structural,electronic,and magnetic properties along with exchange interactions and Curie temperatures for CrZrCoZ(Z=Al,Ga,In,Tl,Si,Pb)quaternary Heusler alloys.The ...Using the first-principles calculations,we study the structural,electronic,and magnetic properties along with exchange interactions and Curie temperatures for CrZrCoZ(Z=Al,Ga,In,Tl,Si,Pb)quaternary Heusler alloys.The results show that the CrZrCoZ alloys are half-metallic ferrimagnets,and their total spin magnetic moments,which are mainly carried by the Cr atom,obey the Slater-Pauling rule.Analysis of local density of states confirms that the exchange splitting between eg and t2g states leads to the formation of half-metallic gap.According to the calculated Heisenberg exchange coupling parameters,it is found that the Cr(A)-Cr(A)and Cr(A)-Zr(B)exchanges dominate the appearance of ferrimagnetic states in CrZrCoZ(Z=Al,Ga,In,Tl,Pb)alloys,and it is the Cr(A)-Zr(B)and Zr(B)-Zr(B)exchanges for CrZrCoSi alloy.Finally,we estimate the Curie temperatures of CrZrCoZ by using mean-field approximation,it is found that the CrZrCoZ(Z=Al,Ga,In,Tl,Pb)alloys have noticeably higher Curie temperatures than room temperature.So,we expect that the CrZrCoZ alloys are promising candidates in spintronic applications in future.展开更多
In this paper, acoustic scattering from the system comprised of a cloaked object and the multilayer cloak with only one single pair of isotropic media is analyzed with a recursive numerical method. The designed acoust...In this paper, acoustic scattering from the system comprised of a cloaked object and the multilayer cloak with only one single pair of isotropic media is analyzed with a recursive numerical method. The designed acoustic parameters of the isotropic cloak media are assumed to be single-negative, and the resulting cloak can reduce acoustic scattering from an acoustic sensor while allowing it to receive external information. Several factors that may influence the performance of the cloak, including the number of layers and the acoustic dissipation of the medium are fully analyzed. Furthermore, the possibility of achieving acoustic invisibility with positive acoustic parameters is proposed by searching the optimum value in the parameter space and minimizing the scattering cross-section.展开更多
In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utili...In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utilized to regulate signal communication between sensors and filters. Here, the randomly varying channel parameters are represented by a set of stochastic variables whose occurring probabilities are permitted to exhibit bounded uncertainty. Employing the spherical-radial cubature principle, a local filter under AaF relays is initially constructed. This construction ensures and minimizes an upper bound of the filtering error covariance by designing an appropriate filter gain. Subsequently, the local filters are fused through the application of the covariance intersection fusion rule. Furthermore, the uniform boundedness of the filtering error covariance's upper bound is investigated through establishing certain sufficient conditions. The effectiveness of the proposed CKFF scheme is ultimately validated via a simulation experiment concentrating on a three-phase induction machine.展开更多
This paper investigates the anomaly-resistant decentralized state estimation(SE) problem for a class of wide-area power systems which are divided into several non-overlapping areas connected through transmission lines...This paper investigates the anomaly-resistant decentralized state estimation(SE) problem for a class of wide-area power systems which are divided into several non-overlapping areas connected through transmission lines. Two classes of measurements(i.e., local measurements and edge measurements) are obtained, respectively, from the individual area and the transmission lines. A decentralized state estimator, whose performance is resistant against measurement with anomalies, is designed based on the minimum error entropy with fiducial points(MEEF) criterion. Specifically, 1) An augmented model, which incorporates the local prediction and local measurement, is developed by resorting to the unscented transformation approach and the statistical linearization approach;2) Using the augmented model, an MEEF-based cost function is designed that reflects the local prediction errors of the state and the measurement;and 3) The local estimate is first obtained by minimizing the MEEF-based cost function through a fixed-point iteration and then updated by using the edge measuring information. Finally, simulation experiments with three scenarios are carried out on the IEEE 14-bus system to illustrate the validity of the proposed anomaly-resistant decentralized SE scheme.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11864021)Foundation of A Hundred Youth Talents Training Program of Lanzhou Jiaotong University,China,the Key Talent Foundation of Gansu Province,China(Grant No.2020RCXM100)Excellent Research Team of Lanzhou Jiaotong University,China(Grant No.201803).
文摘Using the first-principles calculations,we study the structural,electronic,and magnetic properties along with exchange interactions and Curie temperatures for CrZrCoZ(Z=Al,Ga,In,Tl,Si,Pb)quaternary Heusler alloys.The results show that the CrZrCoZ alloys are half-metallic ferrimagnets,and their total spin magnetic moments,which are mainly carried by the Cr atom,obey the Slater-Pauling rule.Analysis of local density of states confirms that the exchange splitting between eg and t2g states leads to the formation of half-metallic gap.According to the calculated Heisenberg exchange coupling parameters,it is found that the Cr(A)-Cr(A)and Cr(A)-Zr(B)exchanges dominate the appearance of ferrimagnetic states in CrZrCoZ(Z=Al,Ga,In,Tl,Pb)alloys,and it is the Cr(A)-Zr(B)and Zr(B)-Zr(B)exchanges for CrZrCoSi alloy.Finally,we estimate the Curie temperatures of CrZrCoZ by using mean-field approximation,it is found that the CrZrCoZ(Z=Al,Ga,In,Tl,Pb)alloys have noticeably higher Curie temperatures than room temperature.So,we expect that the CrZrCoZ alloys are promising candidates in spintronic applications in future.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274168,11374157,11174138,11174139,11222442,and 81127901)the National Basic Research Program of China(Grant Nos.2010CB327803 and 2012CB921504)
文摘In this paper, acoustic scattering from the system comprised of a cloaked object and the multilayer cloak with only one single pair of isotropic media is analyzed with a recursive numerical method. The designed acoustic parameters of the isotropic cloak media are assumed to be single-negative, and the resulting cloak can reduce acoustic scattering from an acoustic sensor while allowing it to receive external information. Several factors that may influence the performance of the cloak, including the number of layers and the acoustic dissipation of the medium are fully analyzed. Furthermore, the possibility of achieving acoustic invisibility with positive acoustic parameters is proposed by searching the optimum value in the parameter space and minimizing the scattering cross-section.
基金supported in part by the National Natural Science Foundation of China(12171124,61933007)the Natural Science Foundation of Heilongjiang Province of China(ZD2022F003)+2 种基金the National High-End Foreign Experts Recruitment Plan of China(G2023012004L)the Royal Society of UKthe Alexander von Humboldt Foundation of Germany
文摘In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utilized to regulate signal communication between sensors and filters. Here, the randomly varying channel parameters are represented by a set of stochastic variables whose occurring probabilities are permitted to exhibit bounded uncertainty. Employing the spherical-radial cubature principle, a local filter under AaF relays is initially constructed. This construction ensures and minimizes an upper bound of the filtering error covariance by designing an appropriate filter gain. Subsequently, the local filters are fused through the application of the covariance intersection fusion rule. Furthermore, the uniform boundedness of the filtering error covariance's upper bound is investigated through establishing certain sufficient conditions. The effectiveness of the proposed CKFF scheme is ultimately validated via a simulation experiment concentrating on a three-phase induction machine.
基金supported in part by the National Natural Science Foundation of China(61933007, U21A2019, 62273005, 62273088, 62303301)the Program of Shanghai Academic/Technology Research Leader of China (20XD1420100)+2 种基金the Hainan Province Science and Technology Special Fund of China(ZDYF2022SHFZ105)the Natural Science Foundation of Anhui Province of China (2108085MA07)the Alexander von Humboldt Foundation of Germany。
文摘This paper investigates the anomaly-resistant decentralized state estimation(SE) problem for a class of wide-area power systems which are divided into several non-overlapping areas connected through transmission lines. Two classes of measurements(i.e., local measurements and edge measurements) are obtained, respectively, from the individual area and the transmission lines. A decentralized state estimator, whose performance is resistant against measurement with anomalies, is designed based on the minimum error entropy with fiducial points(MEEF) criterion. Specifically, 1) An augmented model, which incorporates the local prediction and local measurement, is developed by resorting to the unscented transformation approach and the statistical linearization approach;2) Using the augmented model, an MEEF-based cost function is designed that reflects the local prediction errors of the state and the measurement;and 3) The local estimate is first obtained by minimizing the MEEF-based cost function through a fixed-point iteration and then updated by using the edge measuring information. Finally, simulation experiments with three scenarios are carried out on the IEEE 14-bus system to illustrate the validity of the proposed anomaly-resistant decentralized SE scheme.
