3,414 research outputs found

    Topological quantum memory interfacing atomic and superconducting qubits

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    We propose a scheme to manipulate a topological spin qubit which is realized with cold atoms in a one-dimensional optical lattice. In particular, by introducing a quantum opto-electro-mechanical interface, we are able to first transfer a superconducting qubit state to an atomic qubit state and then to store it into the topological spin qubit. In this way, an efficient topological quantum memory could be constructed for the superconducting qubit. Therefore, we can consolidate the advantages of both the noise resistance of the topological qubits and the scalability of the superconducting qubits in this hybrid architecture.Comment: v2: Accepted for publication in Science China-Physics, Mechanics & Astronom

    Research on UBI auto insurance pricing model based on parameter adaptive SAPSO optimal fuzzy controller

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    Aiming at the problem of “dynamic” accurate determination of rates in UBI auto insurance pricing, this paper proposes a UBI auto insurance pricing model based on fuzzy controller and optimizes it with a parameter adaptive SASPO. On the basis of the SASPO algorithm, the movement direction of the particles can be mutated and the direction can be dynamically controlled, the inertia weight value is given by the distance between the particle and the global optimal particle, and the learning factor is calculated according to the change of the fitness value, which realizes the parameter in the running process. Effective self-adjustment. A five-dimensional fuzzy controller is constructed by selecting the monthly driving mileage, the number of violations, and the driving time at night in the UBI auto insurance data. The weights are used to form fuzzy rules, and a variety of algorithms are used to optimize the membership function and fuzzy rules and compare them. The research results show that, compared with other algorithms, the parameter adaptive SAPAO algorithm can calculate more reasonable, accurate and high-quality fuzzy rules and membership functions when processing UBI auto insurance data. The accuracy and robustness of UBI auto insurance rate determination can realize dynamic and accurate determination of UBI auto insurance rates

    Relaxor behavior and photocatalytic properties of BaBi2Nb2O9

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    Lead‐free Aurivillius phase BaBi2Nb2O9 powders were prepared by solid‐state reaction. Ferroelectric measurements on BaBi2Nb2O9 (BBNO) ceramics at room temperature provided supporting evidence for the existence of polar nanoregions (PNRs) and their reversible response to an external electric field, indicating relaxor behavior. The photocatalytic degradation of Rhodamine B reached 12% after 3 hours irradiation of BBNO powders under simulated solar light. Silver (Ag) nanoparticles were photochemically deposited onto the surface of the BBNO powders and found to act as electron traps, facilitating the separation of photoexcited charge carriers; thus, the photocatalytic performance was significantly improved. The present study is the first examination of the photochemical reactivity of a relaxor ferroelectric within the Aurivillius family with PNRs

    Relaxor behavior and photocatalytic properties of BaBi₂Nb₂O₉

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    Lead‐free Aurivillius phase BaBi2Nb2O9 powders were prepared by solid‐state reaction. Ferroelectric measurements on BaBi2Nb2O9 (BBNO) ceramics at room temperature provided supporting evidence for the existence of polar nanoregions (PNRs) and their reversible response to an external electric field, indicating relaxor behavior. The photocatalytic degradation of Rhodamine B reached 12% after 3 hours irradiation of BBNO powders under simulated solar light. Silver (Ag) nanoparticles were photochemically deposited onto the surface of the BBNO powders and found to act as electron traps, facilitating the separation of photoexcited charge carriers; thus, the photocatalytic performance was significantly improved. The present study is the first examination of the photochemical reactivity of a relaxor ferroelectric within the Aurivillius family with PNRs

    Coping flexibility in college students with depressive symptoms

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    Background: The current study explored the prevalence of depressed mood among Chinese undergraduate students and examined the coping patterns and degree of flexibility of flexibility of such patterns associated with such mood. Methods: A set of questionnaire assessing coping patterns, coping flexibility, and depressive symptoms were administered to 428 students (234 men and 194 women). Results: A total of 266 participants both completed the entire set of questionnaires and reported a frequency of two or more stressful life events (the criterion needed to calculate variance in perceived controllability). Findings showed that higher levels of depressive symptoms were significantly associated with higher levels of both event frequency (r = .368, p < .001) and event impact (r = .245, p < .001) and lower levels of perceived controllability (r = -.261, p < .001), coping effectiveness (r = -.375, p < .001), and ratio of strategy to situation fit (r = -.108, p < .05). Depressive symptoms were not significantly associated with cognitive flexibility (variance of perceived controllability; r = .031, p = .527), Gender was not a significant moderator of any of the reported associations. Conclusions: Findings indicate that Chinese university students with depressive symptoms reported experiencing a greater number of negative events than did non-depressed university students. In addition, undergraduates with depressive symptoms were more likely than other undergraduates to utilize maladaptive coping methods. Such findings highlight the potential importance of interventions aimed at helping undergraduate students with a lower coping flexibility develop skills to cope with stressful life events.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000282298600001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Health Care Sciences & ServicesHealth Policy & ServicesSCI(E)SSCI4ARTICLEnull

    New Family of Robust 2D Topological Insulators in van der Waals Heterostructures

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    We predict a new family of robust two-dimensional (2D) topological insulators in van der Waals heterostructures comprising graphene and chalcogenides BiTeX (X=Cl, Br and I). The layered structures of both constituent materials produce a naturally smooth interface that is conducive to proximity induced new topological states. First principles calculations reveal intrinsic topologically nontrivial bulk energy gaps as large as 70-80 meV, which can be further enhanced up to 120 meV by compression. The strong spin-orbit coupling in BiTeX has a significant influence on the graphene Dirac states, resulting in the topologically nontrivial band structure, which is confirmed by calculated nontrivial Z2 index and an explicit demonstration of metallic edge states. Such heterostructures offer an unique Dirac transport system that combines the 2D Dirac states from graphene and 1D Dirac edge states from the topological insulator, and it offers new ideas for innovative device designs

    Investigations of double layer phase change walls with expanded graphite on the temperature and energy consumption

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    This is the final version. Available on open access from Elsevier via the DOI in this recordIn this paper, a composite structure double layer phase change walls with expanded graphite (EG) was investigated. By adding the EG, the time needed for the phase change process and the wall to work was both accelerated. The effect of composite phase change walls on the indoor thermal comfort and building energy consumption were investigated experimentally. The results show that the double layer phase change wall with the EG can suppress the temperature fluctuation. In addition, it simulated the cooling and heating loads with or without phase change walls based on the climatic conditions in Shanghai. The results show that the heating load in winter is reduced by more than 15%. The simulated values are consistent with the experimental values, and the temperature deviation at the same measuring point within the same period is small. The maximum temperature change between the experimental and simulated values is less than 1 °C. The double layer phase change wall with the EG can reduce the temperature fluctuation and improve the indoor thermal comfort.National Natural Science Foundation of ChinaYouth Eastern Scholar Program of Shanghai Municipal Education CommissionShanghai Municipal Science and Technology Committee of Shanghai outstanding academic leaders pla

    Methanol conversion on borocarbonitride catalysts: Identification and quantification of active sites

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    Borocarbonitrides (BCNs) have emerged as highly selective catalysts for the oxidative dehydrogenation (ODH) reaction. However, there is a lack of in-depth understanding of the catalytic mechanism over BCN catalysts due to the complexity of the surface oxygen functional groups. Here, BCN nanotubes with multiple active sites are synthesized for oxygen-assisted methanol conversion reaction. The catalyst shows a notable activity improvement for methanol conversion (29%) with excellent selectivity to formaldehyde (54%). Kinetic measurements indicate that carboxylic acid groups on BCN are responsible for the formation of dimethyl ether, while the redox catalysis to formaldehyde occurs on both ketonic carbonyl and boron hydroxyl (B-OH) sites. The ODH reaction pathway on the B-OH site is further revealed by in situ infrared, x-ray absorption spectra, and density functional theory. The present work provides physical-chemical insights into the functional mechanism of BCN catalysts, paving the way for further development of the underexplored nonmetallic catalytic systems

    Memristive System Based Image Processing Technology: A Review and Perspective

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    Copyright: © 2021 by the authors. As the acquisition, transmission, storage and conversion of images become more efficient, image data are increasing explosively. At the same time, the limitations of conventional computational processing systems based on the Von Neumann architecture continue to emerge, and thus, improving the efficiency of image processing has become a key issue that has bothered scholars working on images for a long time. Memristors with non-volatile, synapse-like, as well as integrated storage-and-computation properties can be used to build intelligent processing systems that are closer to the structure and function of biological brains. They are also of great significance when constructing new intelligent image processing systems with non-Von Neumann architecture and for achieving the integrated storage and computation of image data. Based on this, this paper analyses the mathematical models of memristors and discusses their applications in conventional image processing based on memristive systems as well as image processing based on memristive neural networks, to investigate the potential of memristive systems in image processing. In addition, recent advances and implications of memristive system-based image processing are presented comprehensively, and its development opportunities and challenges in different major areas are explored as well. By establishing a complete spectrum of image processing technologies based on memristive systems, this review attempts to provide a reference for future studies in the field, and it is hoped that scholars can promote its development through interdisciplinary academic exchanges and cooperationNational Natural Science Foundation of China (Grant U1909201, Grant 62001149); Natural Science Foundation of Zhejiang Province (Grant LQ21F010009)
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