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arXiv 2020年

作者： Li, Kejun J. Xu, J.C. Xie, J.L. Feng, W. Yunnan Observatories CAS Kunming650011 China Research Center of Analysis and Measurement Kunming University of Science and Technology Kunming650093 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China Key Laboratory of Solar Activity National Astronomical Observatories CAS Beijing100012 China

Differential rotation is the basis of the solar dynamo theory. Synoptic maps of He I intensity from Carrington rotations 2032 to 2135 are utilized to investigate the differential rotation of the solar chromosphere in the He I absorption line. The chromosphere is surprisingly found to rotate faster than the photosphere below it. The anomalous heating of the chromosphere and corona has been a big problem in modern astronomy. It is speculated that the small-scale magnetic elements with magnetic flux in the range of (2.9−32.0)×1018 Mx which are anchored in the leptocline, heat the quiet chromosphere to present the anomalous temperature increase, causing it to rotate at the same rate as the leptocline. The differential of rotation rate in the chromosphere is found to be strengthened by strong magnetic fields, but in stark contrast, at the photosphere strong magnetic fields repress the differential of rotation rate. A plausible explanation is given for these findings. Copyright © 2020, The Authors. All rights reserved.

关键词： Rotation rate

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Positive-Parity Linear-Chain Molecular Band in C16

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Physical Review Letters 2020年第19期124卷 192501-192501页

作者： Y. Liu Y. L. Ye J. L. Lou X. F. Yang T. Baba M. Kimura B. Yang Z. H. Li Q. T. Li J. Y. Xu Y. C. Ge H. Hua J. S. Wang Y. Y. Yang P. Ma Z. Bai Q. Hu W. Liu K. Ma L. C. Tao Y. Jiang L. Y. Hu H. L. Zang J. Feng H. Y. Wu J. X. Han S. W. Bai G. Li H. Z. Yu S. W. Huang Z. Q. Chen X. H. Sun J. J. Li Z. W. Tan Z. H. Gao F. F. Duan J. H. Tan S. Q. Sun Y. S. Song School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China Kitami Institute of Technology 090-8507 Kitami Japan Department of Physics Hokkaido University 060-0810 Sapporo Japan School of Science Huzhou University Huzhou 313000 China Institute of Modern Physics Chinese Academy of Science Lanzhou 730000 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin 150001 China

An inelastic excitation and cluster-decay experiment H2(C16,He4+Be12 or He6+Be10)H2 was carried out to investigate the linear-chain clustering structure in neutron-rich C16. For the first time, decay paths from the C16 resonances to various states of the final nuclei were determined, thanks to the well-resolved Q-value spectra obtained from the threefold coincident measurement. The close-threshold resonance at 16.5 MeV is assigned as the Jπ=0+ band head of the predicted positive-parity linear-chain molecular band with (3/2π−)2(1/2σ−)2 configuration, according to the associated angular correlation and decay analysis. Other members of this band were found at 17.3, 19.4, and 21.6 MeV based on their selective decay properties, being consistent with the theoretical predictions. Another intriguing high-lying state was observed at 27.2 MeV which decays almost exclusively to He6+Be10(∼6 MeV) final channel, corresponding well to another predicted linear-chain structure with the pure σ-bond configuration.

关键词： Alpha decay Cluster models Direct reactions Few-body systems Lifetimes & widths Nuclear reactions Nuclear spin & parity Nuclear structure & decays Resonance reactions Unstable nuclei induced nuclear reactions

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Diagnosis of pairing symmetry by vortex and edge spectra in kagome superconductors

arXiv

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arXiv 2022年

作者： Ding, Peize Lee, Ching Hua Wu, Xianxin Thomale, Ronny Institute for Theoretical Physics University of Würzburg Am Hubland WürzburgD-97074 Germany University of Science and Technology of China Hefei230026 China Department of Physics National University of Singapore Singapore117542 Singapore Max-Planck-Institut für Festkörperforschung Heisenbergstrasse 1 StuttgartD-70569 Germany CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China

Layered kagome metals AV3Sb5 (A=K, Rb, Cs) exhibit diverse correlated electron phenomena. It includes charge density wave formation and superconductivity the pairing symmetry of which, however, is controversial due to contradictory experimental evidence. Through calculations based on real-space lattice models at the mean-field level, we investigate the vortex and surface spectra of all competitive pairing propensities suggested for AV3Sb5 from a weak coupling analysis of unconventional superconductivity. Chiral p-wave pairing emerges as the only option to host Majorana bound states in the vortex core. We find chiral edge states for both p-wave and d-wave pairing, along with flat Andreev surface bound states for f-wave pairing. Our results expand the fingerprint of superconducting pairing, and thus will contribute to resolving the nature of superconductivity in AV3Sb5. Copyright © 2022, The Authors. All rights reserved.

关键词： Vortex flow

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UNet-ESPC-Cascaded Super-Resolution Reconstruction in Spectral CT

UNet-ESPC-Cascaded Super-Resolution Reconstruction in Spectr...

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International Conference on Signal Processing Proceedings (ICSP)

作者： Zhouxia Li Xiaoni Wang Lihui Wang Wen Ji Miaomiao Zhang Yuemin Zhu Feng Yang School of Computer and Information Technology Beijing Jiaotong University Beijing China Key Laboratory of Intelligent Medical Image Analysis and Precise Diagnosis of Guizhou Province College of Computer Science and Technology Guizhou University Guiyang China Beijing Key Laboratory of Mobile Computing and Pervasive Device Institute of Computing Technology Chinese Academy of Sciences Beijing China College of Information Engineering Capital Normal University Beijing China INSA Lyon CNRS Inserm Univ Lyon Lyon France National Library of Medicine National Institute of Health Bethesda MD USA

ISBN: (数字)9781728144801

ISBN: (纸本)9781728144818

Spectral CT based on photon counting detectors is a promising imaging modality since it provides the possibility of both obtaining CT images from multi-energy bins with a single X-ray exposure and allowing low-dose imaging. However, the image quality such as spatial resolution reconstructed from multiple energy bins is degraded because of the use of narrow energy bins in spectral CT. We propose to use deep learning methods for super-resolution reconstruction of spectral CT images. To this end, we introduce an UNet-ESPC-cascaded model and perform a patch-based training to obtain the optimal parameters of the model. Experimental results on physical phantom datasets demonstrated that our deep learning based reconstruction method can reduce the F form error between the reconstructed super-resolution CT image and the ground truth, by 11.6% and 5.66% with respect to respectively bilinear-interpolation-based reconstruction and iterative back projection methods. Our method achieves best results with a patch size of 20 and a stride of 15.

关键词： Image reconstruction Computed tomography Superresolution Interpolation Energy resolution Deep learning Training

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Optimizing wind turbine blade performance: A multi-objective approach for power, load and stall characteristics

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Energy 2025年 331卷

作者： Siyuan Wu Chang Cai Lei Zhang Zhiqiang Hu Xiangyu Sun Xiaohui Zhong Chaoyi Peng Keqilao Meng Jianyu Kou Qing’an Li National Energy Wind Turbine Blade R&D Center Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China The Key Laboratory of Wind Energy Utilization of Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China School of Engineering Newcastle University Newcastle Upon Tyne NE1 7RU UK Goldwind Science&Technology Co. Ltd Beijing 100176 China Zhuzhou Times New Materials Technology Co. Ltd Zhuzhou 412007 China School of Energy and Power Engineering Inner Mongolia University of Technology Hohhot 010051 China Inner Mongolia Energy Group Hohhot 010051 China

Ultra-long flexible wind turbine blades are essential for advancing large-scale and offshore wind energy projects. Despite significant progress, optimizing these blades remains a complex challenge due to the need to balance multiple performance objectives simultaneously. In this study, we developed a multi-objective optimization approach for wind turbine blade design that quantitatively addresses power, load, and stall characteristics. To validate the methodology, it was applied to the design of a 2MW wind turbine blade, and the optimized design was compared with a base blade. Sensitivity analysis of the optimization weight parameters was also conducted to enhance the robustness of the approach. The results indicate notable improvements in key performance metrics, including a 1.7% increase in average power generation, a 2.1% reduction in the maximum flap-wise moment at the blade root, and a 1.5°decrease in the running angle of attack. Moreover, the critical tip speed ratio (TSR) decreased by 0.6, aligning with the stall angle and indicating enhanced stall performance. This study not only demonstrates the effectiveness of the multi-objective coupling optimization method but also introduces innovative techniques for stall risk assessment and optimal TSR control, thereby contributing to the advancement of wind turbine blade design.

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Vanadium doping inhibit the Jahn−Teller effect of Mn 3+ for high-performance aqueous zinc ion battery

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Chinese Chemical Letters 2025年

作者： Le Li Shaofeng Jia Shi Yue Yuanyuan Yang Chao Tan Conghui Wang Hengwei Qiu Yongqiang Ji Minghui Cao Zige Tai Dan Zhang Shaanxi Key Laboratory of Industrial Automation School of Mechanical Engineering Shaanxi University of Technology Hanzhong 723001 China School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China Shaanxi Key Laboratory of Catalysis School of Chemistry and Environment Science Shaanxi University of Technology Hanzhong 723001 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of New Energy North China Electric Power University Beijing 102206 China Institute of Physics Henan Academy of Sciences Zhengzhou 450046 China School of Electronic and Information Engineering Qingdao University Qingdao 266071 China

The Jahn-Teller effect of Mn 3+ brings drastic structural changes to MnO 2 -based materials and accelerates the destruction and deactivation of the internal structure of the materials, thus leading to severe capacity fading and phase change of MnO 2 -based materials in aqueous zinc ion batteries (AZIBs). Here, this study doped high valent vanadium ions into MnO 2 (VMO-x) to inhibit manganese's Jahn−Teller effect. Through a series of characterizations, such as X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM), it was discovered that the introduction of vanadium ions effectively increased the interlayer spacing of MnO 2 , facilitating the transport of ions into the interlayer. Additionally, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated vanadium doped could effectively adjust the electronic structure, decreasing the average oxidation state of manganese, thereby inhibiting the Jahn−Teller effect and significantly enhancing the stability of the VMO-x cathode. The theoretical calculation showed that introducing vanadium ions enhanced the interaction between the main material and Zn 2+ , optimized its electron transport capacity, and led to better electrical conductivity and reaction kinetics of the VMO-5. Benefiting from this, the VMO-5 cathode exhibited an outstanding capacity of 283 mAh/g and maintained a capacity retention rate of 79% after 2000 cycles, demonstrating excellent electrochemical performance. Furthermore, the mechanism of H + /Zn 2+ co-intercalation/deintercalation was demonstrated through mechanism analysis. Finally, the test results of the pouch cell demonstrated the excellent flexibility and safety exhibited by the VMO-5 make it have great potential in flexible devices. This work presented a novel approach to doping high valence metal ions into manganese-based electrodes for AZIBs.

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Electronic Skin from High-Throughput Fabrication of Intrinsically Stretchable Lead Zirconate Titanate Elastomer

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研究（英文） 2021年第2期2020卷 377-387页

作者： Yiming Liu Huanxi Zheng Ling Zhao Shiyuan Liu Kuanming Yao Dengfeng Li Chunki Yiu Shenghan Gao Raudel Avila Pakpong Chirarattananon Lingqian Chang Zuankai Wang Xian Huang Zhaoqian Xie Zhengbao Yang Xinge Yu Department of Biomedical Engineering City University of Hong KongHong Kong 999077China Department of Mechanical Engineering City University of Hong KongHong Kong 999077China Department of Biomedical Engineering Tianjin UniversityTianjin 300000China Department of Mechanical Engineering McCormick School of EngineeringNorthwestern UniversityEvanstonIL 60208USA School of Biology Science and Medical Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian 116024China

Electronic skin made of thin,soft,stretchable devices that can mimic the human skin and reconstruct the tactile sensation and perception offers great opportunities for prosthesis sensing,robotics controlling,and human-machine *** materials and mechanics engineering of thin film devices has proven to be an efficient route to enable and enhance flexibility and stretchability of various electronic skins;however,the density of devices is still low owing to the limitation in existing fabrication ***,we report a high-throughput one-step process to fabricate large tactile sensing arrays with a sensor density of 25 sensors/cm2 for electronic skin,where the sensors are based on intrinsically stretchable piezoelectric lead zirconate titanate (PZT) *** PZT elastomer sensor arrays with great uniformity and passive-driven manner enable high-resolution tactile sensing,simplify the data acquisition process,and lower the manufacturing *** high-throughput fabrication process provides a general platform for integrating intrinsically stretchable materials into large area,high device density soft electronics for the next-generation electronic skin.

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Maxwell-Wagner Relaxations in Ca-, Sm- and Nd-doped Ceria

Research Square

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Research Square 2021年

作者： Ahmed, Rida Wang, Shuting T. ur Rehman, Sajid Sun, Jie Wang, Jin Si, Renjun Zhu, An Kang Yu, Yi Li, Qiuju Wang, Chunchang Laboratory of Dielectric Functional Materials School of Physics & Material Science Anhui University Hefei230601 China High Magnetic Field Laboratory Chinese Academy of Sciences Anhui Hefei230031 China State Key Laboratory of ASIC & System School of Microelectronics Fudan University Shanghai200433 China Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information Technology Anhui University Hefei230601 China State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China

Doped ceria, i.e. Ce1-xMxO2-d with M being dopant metal, has been a focus of great attention for SOFCs due to its high oxygen conduction. In the past literature, the dielectric relaxations in these materials have been ascribed to be caused by defect associates (MCeʺ-Vö) possessing different MCeʺ and Vö distances. But we believe that with changing measurement and analysis techniques it is necessary to invest our time to re-examine the already reported materials and to again take a detailed investigation of the underlying phenomenon behind their dielectric relaxations. Thus, we have used solid-state reaction to prepare Ce1-xMxO2-δ with M=Ca, Sm, and Nd in x=0.1, 0.2, and 0.3 ratios, respectively. The as-prepared and post annealed samples were tested for dielectric properties from 300-1080 K with varying frequencies. The low-temperature relaxation (R1) was argued to be a Maxwell-Wagner relaxation caused by humidity sensitivity. The high-temperature relaxation (R2) was ascribed to be caused by hopping motion of oxygen vacancies. This fact was also supported by detailed analysis of impedance spectra. While, according to the previous reports this relaxation is because of oxygen-vacancy-dopant defect pair. © 2021, CC BY.

关键词： Oxygen vacancies

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Valley-dependent properties of monolayer MoSi2N4, WSi2N4, and MoSi2As4

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Physical Review B 2020年第23期102卷 235435-235435页

作者： Si Li Weikang Wu Xiaolong Feng Shan Guan Wanxiang Feng Yugui Yao Shengyuan A. Yang School of Physics and Electronics Hunan Normal University Changsha Hunan 410081 China Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore 487372 Singapore State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology Beijing 100081 China Center for Quantum Transport and Thermal Energy Science School of Physics and Technology Nanjing Normal University Nanjing 210023 China

In a recent work, new two-dimensional materials, monolayer MoSi2N4 and WSi2N4, were successfully synthesized in experiment, and several other monolayer materials with a similar structure, such as MoSi2As4, were predicted [Hong et al., science 369, 670 (2020)]. Here, based on first-principles calculations and theoretical analysis, we investigate the electronic and optical properties of monolayer MoSi2N4, WSi2N4, and MoSi2As4. We show that these materials are semiconductors, with a pair of Dirac-type valleys located at the corners of the hexagonal Brillouin zone. Due to the broken inversion symmetry and the effect of spin-orbit coupling, the valley fermions manifest spin-valley coupling, valley-contrasting Berry curvature, and valley-selective optical circular dichroism. We also construct the low-energy effective model for the valleys, calculate the spin Hall conductivity and the permittivity, and investigate the strain effect on the band structure. Our result reveals interesting valley physics in monolayer MoSi2N4, WSi2N4, and MoSi2As4, suggesting their great potential for valleytronics and spintronics applications.

关键词： Electrical conductivity Spin-orbit coupling Spintronics Valleytronics 2-dimensional systems Band structure methods Bloch wave theory Density functional approximations Density functional calculations Density functional theory Electronic structure First-principles calculations Symmetries Wannier function methods k dot p method

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The ALMA-QUARKS Survey: Fibers’ role in star formation unveiled in an intermediate-mass protocluster region of the Vela D cloud

arXiv

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arXiv 2024年

作者： Yang, Dongting Liu, Hong-Li Liu, Tie Tej, Anandmayee Liu, Xunchuan He, Jinhua Garay, Guido Stutz, Amelia Zhu, Lei Qin, Sheng-Li Xu, Fengwei Li, Pak-Shing Juvela, Mika García, Pablo Goldsmith, Paul F. Zhang, Siju Tang, Xindi Sanhueza, Patricio Li, Shanghuo Lee, Chang Won Das, Swagat Ranjan Jiao, Wenyu Mai, Xiaofeng Gorai, Prasanta Zhang, Yichen Ren, Zhiyuan Tóth, L. Viktor Hwang, Jihye Bronfman, Leonardo Tatematsu, Kenichi Dewangan, Lokesh Chibueze, James O. Zhang, Suinan Wu, Gang Xie, Jinjin School of physics and astronomy Yunnan University Kunming650091 China Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai200030 China Indian Institute of Space Science and Technology Kerala Thiruvananthapuram695 547 India Yunnan Observatories Chinese Academy of Sciences Yunnan Kunming650216 China Departamento de Astronomía Universidad de Chile Casilla 36-D Santiago Chile Chinese Academy of Sciences South America Center for Astronomy National Astronomical Observatories CAS Beijing100101 China Departamento de Astronomía Universidad de Concepción Av. Esteban Iturra s/n Distrito Universitario 160-C Chile Max Planck Institute for Astronomy Königstuhl 17 HeidelbergD-69117 Germany Chinese Academy of Sciences South America Center for Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Kavli Institute for Astronomy and Astrophysics Peking University 5 Yiheyuan Road Haidian District Beijing100871 China Department of Astronomy Peking University Beijing100871 China Department of Physics University of Helsinki P.O. box 64 FI- 00014 Finland Instituto de Astronomía Universidad Católica del Norte Av. Angamos 0610 Antofagasta Chile Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive PasadenaCA91109 United States Departamento de Astronomía Universidad de Chile Las Condes Santiago7591245 Chile Xinjiang Astronomical Observatory Chinese Academy of Sciences 150 Science 1-Stree Xinjiang Urumqi830011 China Department of Earth and Planetary Sciences Tokyo Institute of Technology Meguro Tokyo152-8551 Japan National Astronomical Observatory of Japan National Institutes of Natural Sciences 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Korea Astronomy and Space Science Institute 776 Daedeokdae-ro Yuseong-gu Daejeon34055 Korea Republic of 217 Gajeong-ro Yuseong-gu Daejeon34113 Korea Republic of Shanghai Astronomical Observatory Chinese Academy o

In this paper, we present a detailed analysis of the IRS 17 filament within the intermediate-mass protocluster IRAS 08448-4343 (of ∼ 103 L☉), using ALMA data from the ATOMS 3-mm and QUARKS 1.3-mm surveys. The IRS 17 filament, which spans ∼54000 au (0.26 pc) in length and ∼4000 au (0.02 pc) in width, exhibits a complex, multi-component velocity field, and harbours hierarchical substructures. These substructures include three bundles of seven velocity-coherent fibers, and 29 dense (n ∼ 108 cm−3) condensations. The fibers have a median length of ∼ 4500 au and a median width of ∼ 1400 au. Among these fibers, four are identified as "fertile", each hosting at least three dense condensations, which are regarded as the "seeds" of star formation. While the detected cores are randomly spaced within the IRS 17 filament based on the 3-mm dust continuum image, periodic spacing (∼ 1600 au) of condensations is observed in the fertile fibers according to the 1.3-mm dust map, consistent with the predictions of linear isothermal cylinder fragmentation models. These findings underscore the crucial role of fibers in star formation and suggest a hierarchical fragmentation process that extends from the filament to the fibers, and ultimately, to the smallest-scale condensations. Copyright © 2024, The Authors. All rights reserved.

关键词： Stars

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