The Experts below are selected from a list of 85059 Experts worldwide ranked by ideXlab platform
Naoto Nagaosa - One of the best experts on this subject based on the ideXlab platform.
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anomalous meissner effect in superconducting junction with spin Active Interface
Physics Procedia, 2014Co-Authors: Takehito Yokoyama, Naoto Nagaosa, Yukio TanakaAbstract:Abstract We investigate Meissner effect in normal metal/superconductor junctions where the Interface is spin-Active. We find that the orbital magnetic susceptibility of the normal metal depends on the temperature in an oscillatory fashion, accompanied by its sign change. Correspondingly, magnetic field and current density can spatially oscillate in the normal metal. These results stem from the generation of odd-frequency pairing due to the spin-Active Interface.
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anomalous meissner effect in a normal metal superconductor junction with a spin Active Interface
Physical Review Letters, 2011Co-Authors: Takehito Yokoyama, Yukio Tanaka, Naoto NagaosaAbstract:: We investigate Meissner effect in normal-metal-superconductor junctions where the Interface is spin Active. We find that orbital magnetic susceptibility of the normal metal shows highly nontrivial behavior. In particular, the magnetic susceptibility depends on the temperature in an oscillatory fashion, accompanied by its sign change. Correspondingly, the magnetic field and current density can spatially oscillate in the normal metal. These results are attributed to the generation of odd-frequency pairing due to the spin-Active Interface.
Gangbing Song - One of the best experts on this subject based on the ideXlab platform.
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Active debonding detection for large rectangular cfsts based on wavelet packet energy spectrum with piezoceramics
Journal of Structural Engineering-asce, 2013Co-Authors: Bin Xu, Bing Li, Gangbing SongAbstract:AbstractThe debonding between the steel tube and the confined concrete core of concrete-filled steel tubes (CFSTs) can weaken the confinement effect of the steel tube on the concrete core and may induce a decrease in the load-carrying capacity and in the ductility. The debonding detection technique for CFSTs is still a challenging problem resulting from the inaccessibility and invisibility of the Interface. In this paper, by embedding piezoelectric lead zirconate titanate (PZT) based functional smart aggregates (SAs) in concrete core as actuators and pasting PZT patches on the predetermined locations of the outer surfaces of the specimen as sensors, a novel Active Interface condition monitoring approach for rectangular CFST members is proposed and is experimentally validated with a scale rectangular CFST specimen with artificial debonding defects. Analysis of the wavelet packet energy spectrum (WPES) of the measurements of PZT patches is carried out, and a damage index, called the weighted variation of WP...
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Active Interface debonding detection of a concrete filled steel tube with piezoelectric technologies using wavelet packet analysis
Mechanical Systems and Signal Processing, 2013Co-Authors: Ting Zhang, Gangbing SongAbstract:Abstract Concrete-Filled Steel Tube (CFST) has been widely adopted in high-rise buildings and bridges as a typical structural member carrying vertical loads in recent years. The debonding between the steel tube and the concrete can dramatically reduce the confinement effect of steel tube on the concrete and decrease the load-carrying capacity and the ductility of the CFST. It is still challenging to develop reliable debonding monitoring and detection techniques for CFST because of the inaccessibility of the Interface. In this study, an Active Interface condition monitoring approach for CFST by the use of lead zirconate titanate (PZT) piezoceramics based functional smart aggregates (SAs) embedded in concrete as actuator and PZT patches bonded on the surface of the steel tube as sensors is proposed and verified experimentally. Laboratory tests are performed on the CFST column, in which the deboning is mimicked by setting four thin styrofoam plates with different sizes on different locations of the four internal surfaces of the steel tube, respectively, before casting the concrete. The responses of the PZT sensors are measured when each SA is excited with sweep sinusoidal signals. According to the Fourier spectra and two evaluation indices based on the wavelet packet analysis on the PZT sensors measurements, the artificially mimicked debonding areas are detected successfully. Analysis on the sensitivity of the two evaluation indices shows that the indices based on wavelet packet analysis are more sensitive to the debonding defect. The proposed PZT based Active debonding monitoring method provides an innovative approach to detect the debonding damage of CFST columns.
Ashwin A Seshia - One of the best experts on this subject based on the ideXlab platform.
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a cold startup sshi rectifier for piezoelectric energy harvesters with increased open circuit voltage
IEEE Transactions on Power Electronics, 2019Co-Authors: G A J Amaratunga, Ashwin A SeshiaAbstract:Piezoelectric vibration energy harvesting has drawn much research interest over the last decade toward the goal of enabling self-sustained wireless sensor nodes. In order to make use of the harvested energy, Interface circuits are needed to rectify and manage the energy. Among all Active Interface circuits, synchronized switch harvesting on inductor (SSHI) and synchronous electric charge extraction are widely employed due to their high energy efficiencies. However, the cold-startup issue still remains, since an Interface circuit needs a stable dc supply and the whole system is completely out of charge at the beginning of implementations or after a certain period of time without input vibration excitation. In this paper, a new cold-startup SSHI Interface circuit is presented, which dynamically increases the open-circuit voltage generated from the piezoelectric transducer in the cold state to start the system under much lower excitation levels. The proposed circuit is designed and fabricated in a 0.18- $\mu$ m CMOS process and experimentally validated together with a custom microelectromechanical system harvester, which is designed with split electrodes to work with the proposed power extraction circuit. The experiments were performed to start the system from the cold state under variable excitation levels. The results show that the proposed system lowers the required excitation level by at least 50% in order to perform a cold startup. This aids restarting of the energy harvesting system under low excitation levels each time it enters the cold state.
Takehito Yokoyama - One of the best experts on this subject based on the ideXlab platform.
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anomalous meissner effect in superconducting junction with spin Active Interface
Physics Procedia, 2014Co-Authors: Takehito Yokoyama, Naoto Nagaosa, Yukio TanakaAbstract:Abstract We investigate Meissner effect in normal metal/superconductor junctions where the Interface is spin-Active. We find that the orbital magnetic susceptibility of the normal metal depends on the temperature in an oscillatory fashion, accompanied by its sign change. Correspondingly, magnetic field and current density can spatially oscillate in the normal metal. These results stem from the generation of odd-frequency pairing due to the spin-Active Interface.
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anomalous meissner effect in a normal metal superconductor junction with a spin Active Interface
Physical Review Letters, 2011Co-Authors: Takehito Yokoyama, Yukio Tanaka, Naoto NagaosaAbstract:: We investigate Meissner effect in normal-metal-superconductor junctions where the Interface is spin Active. We find that orbital magnetic susceptibility of the normal metal shows highly nontrivial behavior. In particular, the magnetic susceptibility depends on the temperature in an oscillatory fashion, accompanied by its sign change. Correspondingly, the magnetic field and current density can spatially oscillate in the normal metal. These results are attributed to the generation of odd-frequency pairing due to the spin-Active Interface.
Black-schaffer, Annica M. - One of the best experts on this subject based on the ideXlab platform.
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Thermoelectricity carried by proximity-induced odd-frequency pairing in ferromagnet/superconductor junctions
'American Physical Society (APS)', 2020Co-Authors: Dutta Paramita, Alves, Kaue R., Black-schaffer, Annica M.Abstract:We explore the role of proximity-induced odd-frequency pairing in the thermoelectricity of a ferromagnet when coupled to a conventional s-wave spin-singlet superconductor through a spin-Active Interface. By varying both the polarization and its direction in the ferromagnet and the interfacial spin-orbit interaction strength, we analyze the behavior of all proximity-induced pair amplitudes in the ferromagnet and their contributions to the thermoelectric coefficients. Based on our results for the Seebeck coefficient, we predict that odd-frequency spin-triplet Cooper pairs are much more efficient than the conventional spin-singlet even-frequency pairs in enhancing thermoelectricity of the junction, and especially mixed-spin triplet pairing is favorable. Our results on the thermoelectric figure of merit show that ferromagnet/superconductor junctions are very good thermoelectric systems when superconductivity is dominated by odd-frequency pairing
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Thermoelectricity carried by proximity-induced odd-frequency pairing in ferromagnet/superconductor junctions
'American Physical Society (APS)', 2020Co-Authors: Dutta Paramita, Alves, Kaue R., Black-schaffer, Annica M.Abstract:We explore the role of proximity-induced odd-frequency pairing in the thermoelectricity of a ferromagnet when coupled to a conventional $s$-wave spin-singlet superconductor through a spin-Active Interface. By varying both the polarization and its direction in the ferromagnet and the interfacial spin-orbit interaction strength, we analyze the behavior of all proximity-induced pair amplitudes in the ferromagnet and their contributions to the thermoelectric coefficients. Based on our results for the Seebeck coefficient, we predict that odd-frequency spin-triplet Cooper pairs are much efficient than the conventional spin-singlet even-frequency pairs in enhancing thermoelectricity of the junction, especially mixed-spin triplet pairing is favorable. Our results on the thermoelectric figure of merit show that ferromagnet/superconductor junctions are very good thermoelectric systems when superconductivity is dominated by odd-frequency pairing.Comment: Published versio
