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arXiv 2020年

作者： Chen, Shi Kang, Hui Peng Chen, Jing Paulus, Gerhard G. School of Physics Peking University Beijing100871 China Center for Applied Physics and Technology HEDPS College of Engineering Peking University Beijing100871 China Institute of Optics and Quantum Electronics Friedrich Schiller University Jena Max-Wien-Platz 1 Jena07743 Germany Helmholtz Institut Jena Frtbelstieg 3 Jena07743 Germany State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan430071 China Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing100088 China Center for Advanced Material Diagnostic Technology College of Engineering Physics Shenzhen Technology University Shenzhen518118 China

Using a three-dimensional semiclassical method, we theoretically investigate frustrated double ionization (FDI) of Ar atoms subjected to strong laser fields. The double-hump photoelectron momentum distribution generated from FDI observed in a recent experiment [S. Larimian et al., Phys. Rev. Research 2, 013021 (2020)] is reproduced by our simulation. We confirm that the observed spectrum is due to recollision. The laser intensity dependence of FDI is investigated. We reveal that the doubly excited sates of Ar atoms and excited states of Ar+ are the dominant pathways for producing FDI at relatively low and high intensities, respectively. Our work demonstrates that at modest intensities, FDI is a general strong-field physical process accompanied with nonsequential double ionization and it is an important consequence of recollision. Copyright © 2020, The Authors. All rights reserved.

关键词： Ionization of gases

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Dual-wavelength synchronously mode-locked Tm-doped bulk laser with terahertz frequency beating

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Chinese Optics Letters 2019年第9期17卷 60-63页

作者： Xinyang Liu Xiaowen Li Shengzhi Zhao Kejian Yan Lei Guo Tao Li Wenchao Qiao Ming Li Baitao Zhang Jingliang He Lihe Zheng Liangbi Su Jun Xu School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and ApplicationShandong UniversityQingdao 266237China Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education) Department of Applied PhysicsBeihang UniversityBeijing 100191China Shenzhen Research Institute of Shandong University Shenzhen 518057China State Key Laboratory of Crystal Materials Institute of Crystal MaterialsShandong UniversityJinan 250100China Key Laboratory of Transparent and Opto-Functional Inorganic Materials Artificial Crystal Research CenterShanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China School of Physics Science and Engineering Institute for Advanced StudyTongji UniversityShanghai 200092China

A dual-wavelength synchronously mode-locked homogeneously broadened bulk laser operating at 1985.6 and1989 nm is presented for the first time, to the best of our knowledge, which delivers a maximum output power of 166 m W and a repetition rate of 85 MHz. The pulse duration was measured to be 16.8 ps by assuming a sech2 pulse shape. The recorded autocorrelation trace showed frequency beating signals with an interval of 3.8 ps and a full width at half-maximum duration of 2 ps, corresponding to an ultrahigh beating frequency of about0.26 THz, which agrees well with the frequency difference of the emitted two spectral peaks. The results indicated that such a kind of dual-wavelength mode-locked Tm:YAlO3 laser could be potentially used for generating terahertz radiations.

关键词： Dual-wavelength synchronously mode-locked Tm-doped bulk laser terahertz frequency

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A Particle Filter and Long Short Term Memory Fusion Algorithm for Failure Prognostic of Proton Exchange Membrane Fuel Cells 29

A Particle Filter and Long Short Term Memory Fusion Algorith...

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第29届中国控制与决策会议

作者： Chunchun Yang Zhiheng Li Bin Liang Weining Lu Xueqian Wang Houde Liu Tsinghua University Graduate School at Shenzhen Shenzhen Key Lab of Space Robotic Technology and Telescience Department of Automation School of Information Science and TechnologyTsinghua University Shenzhen Engineering Lab of Geometry Measurement Technology

ISBN: (纸本)9781509046584

Prognostics and Health Management(PHM) appears to be a promising maintenance strategy which can enhance reliability and reduce maintenance costs of the target *** the process of PHM,Prognostics is the most important and *** approaches can be roughly divided into two categories:model-based methods and data-driven methods,both of which have advantages and *** overcome the limitations of these methods and improve the accuracy and precision of the forecasting,we propose a novel fusion prognostic *** method fuses the Particle Filter(PF,model-based) and Long Short Term Memory(LSTM,data-driven) *** the literature,PF is used by estimating the system state and identifying the parameters of the model for the purpose of ***,it does not have ideal performance due to the lack of measurements in the prediction *** solve this problem,LSTM is used to forecast the measurements and use the results as the observation of *** experiment is applied to the data of Proton Exchange Membrane Fuel Cell Stack from IEEE PHM 2014 Data *** results demonstrate that the proposed method can effectively integrate the advantages of PF and LSTM,which leads to a better forecasting performance than naive PF approach.

关键词： Failure Prognostic LSTM Particle Filter PEMFC

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Electronic-State Manipulation of Surface Titanium Activates Dephosphorylation Over TiO2Near Room Temperature

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Angewandte Chemie 2021年第29期133卷

作者： Quan Wang Dr. Xianfeng Yi Yu-Cheng Chen Yao Xiao Prof. Anmin Zheng Prof. Jian Lin Chen Prof. Yung-Kang Peng Department of Chemistry City University of Hong Kong Hong Kong SAR China State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in Wuhan Key Laboratory of Magnetic Resonance in Biological Systems Wuhan Institute of Physics and Mathematics Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan 430071 China Department of Mechanical Engineering City University of Hong Kong Hong Kong SAR China Department of Science School of Science and Technology The Open University of Hong Kong Hong Kong SAR China City University of Hong Kong Shenzhen Research Institute Shenzhen 518057 China

Dephosphorylation that removes a phosphate group from substrates is an important reaction for living organisms and environmental protection. Although CeO 2 has been shown to catalyze this reaction, cerium is low in natural abundance and has a narrow global distribution (>90 % of these reserves are located within six countries). It is thus imperative to find another element/material with high worldwide abundance that can also efficiently extract the phosphate out of agricultural waste for phosphorus recycle. Using para -nitrophenyl phosphate ( p -NPP) as a model compound, we demonstrate that TiO 2 with a F-modified (001) surface can activate p -NPP dephosphorylation at temperatures as low as 40 °C. By probe-assisted nuclear magnetic resonance (NMR), it was revealed that the strong electron-withdrawing effect of fluorine makes Ti atoms (the active sites) on the (001) surface very acidic. The bidentate adsorption of p -NPP on this surface further promotes its subsequent activation with a barrier ≈20 kJ mol −1 lower than that of the pristine (001) and (101) surfaces, allowing the activation of this reaction near room temperature (from >80 °C).

关键词： dephosphorylation electronic-state manipulation nuclear magnetic resonance surface characterization titanium dioxide

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Piezoelectric thermoelastic dissipation research of piezoelectric harvester under different vibration

Piezoelectric thermoelastic dissipation research of piezoele...

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2018 2nd International Conference on Electronic Information technology and Computer engineering (EITCE 2018)

作者： Yuting Liu Jiahao Deng Yong Ye Zhuo Hou Zuodong Duan Sha Xu School of Mechatronical Engineering Beijing Institute of Technology Science and Technology on Electromechanical Dynamic Control Laboratory Beijing Institute of Technology College of Information Engineering Shenzhen University National Key Laboratory of Electronic Measurement Technology North University of China

Piezoelectric materials are widely used to form piezoelectric energy harvesters. Also, the thermoelastic dissipation always influences the energy harvesting efficiency, during the energy harvest process. Therefore, in this paper, we discuss the effect of thermoelastic dissipation on the piezoelectric harvester through numerical calculation, simulation and experiment. The piezoelectric thermoelastic coupling governing equations under different vibration are derived, which are based on the Euler-Bernoulli beam theory, thermal conduction model and piezoelectric field model. Then, the structure frequency shift and thermoelastic damping are studied via numerical calculation and simulation. Meanwhile, we show the influence of the temperature field on the piezoelectric structure under different vibration modes. Furth more, we research the variations of piezoelectric structure thermoelastic dissipation characteristics under different structure geometry sizes. Based on these analyses, the effect of piezoelectric thermoelastic dissipation on the piezoelectric harvester is researched

关键词： Piezoelectric thermoelastic dissipation research of piezoelectric harvester under different vibration

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Emergent ballistic transport of Bose-Fermi mixtures in one dimension

arXiv

引用

arXiv 2019年

作者： Wang, Sheng Yin, Xiangguo Chen, Yang-Yang Zhang, Yunbo Guan, Xi-Wen State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan430071 China University of Chinese Academy of Sciences Beijing100049 China Institute of Theoretical Physics Shanxi University Taiyuan030006 China Shenzhen Institute for Quantum Science and Engineering Department of Physics Southern University of Science and Technology Shenzhen518055 China Department of Theoretical Physics Research School of Physics and Engineering Australian National University CanberraACT0200 Australia

The degenerate Bose-Fermi (BF) mixtures in one dimension present a novel realization of two decoupled Luttinger liquids with bosonic and fermionic degrees of freedom at low temperatures. However, the transport properties of such decoupled Luttinger liquids of charges have not yet been studied. Here we apply generalized hydrodynamics to study the transport properties of one-dimensional (1D) BF mixtures with delta-function interactions. The initial state is set up as the semi-infinite halves of two 1D BF mixtures with different temperatures, joined together at the time t = 0 and the junction point x = 0. Using the Bethe ansatz solution, we first rigorously prove the existence of conserved charges for both the bosonic and fermionic degrees of freedom, preserving the Euler-type continuity equations. We then analytically obtain the distributions of the densities and currents of the local conserved quantities which solely depend on the ratio ξ = x/t. The left and right moving quasiparticle excitations of the two halves form multiple segmented light-core hydrodynamics that display ballistic transport of the conserved charge densities and currents in different degrees of freedom. Our analytical results provide a deep understanding of the quantum transport of multi-component Luttinger liquids in quantum systems with both bosonic and fermionic statistics. Copyright © 2019, The Authors. All rights reserved.

关键词： Transport properties

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Efficient Long-Range Triplet Exciton Transport by Metal–Metal Interaction at Room Temperature

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Angewandte Chemie 2021年第10期134卷

作者： Dr. Qingyun Wan Dr. Dian Li Jiading Zou Dr. Tengfei Yan Dr. Ruidan Zhu Dr. Ke Xiao Shuai Yue Prof. Xiaodong Cui Prof. Yuxiang Weng Prof. Chi-Ming Che Department of Chemistry State Key Laboratory of Synthetic Chemistry HKU-CAS Joint Laboratory on New Materials The University of Hong Kong Pokfulam Road Hong Kong China Department of Physics The University of Hong Kong Pokfulam Road Hong Kong China Beijing National Laboratory for Condensed Matter Physics Laboratory of Soft Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Graduate School of China Academy of Engineering Physics Beijing 100193 P.R. China CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology Beijing 100190 P.R. China HKU Shenzhen Institute of Research & Innovation Shenzhen 518057 China

Efficient and long-range exciton transport is critical for photosynthesis and opto-electronic devices, and for triplet-harvesting materials, triplet exciton diffusion length ( ) and coefficient ( ) are key parameters in determining their performances. Herein, we observed that Pt II and Pd II organometallic nanowires exhibit long-range anisotropic triplet exciton L D of 5–7 μm along the M−M direction using direct photoluminescence (PL) imaging technique by low-power continuous wave (CW) laser excitation. At room temperature, via a combined triplet–triplet annihilation (TTA) analysis and spatial PL imaging, an efficient triplet exciton diffusion was observed for the Pt II and Pd II nanowires with extended close M−M contact, while is absent in nanowires without close M−M contact. Two-dimensional electronic spectroscopy (2DES) and calculations revealed a significant contribution of the delocalized 1/3 [dσ*(M−M)→π*] excited state during the exciton diffusion modulated by the M−M distance.

关键词： Delocalized Excited State Energy Transfer Metal–Metal Interactions Supramolecular Polymer Triplet Exciton

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Pose measurement for Capture of Large Satellite Docking Ring Based on Double-Line Structured Light Vision

Pose Measurement for Capture of Large Satellite Docking Ring...

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2017 2nd International Conference on Materials Science,Machinery and Energy engineering(MSMEE 2017)

作者： Jun Yang Xuehai Gao Zhiheng Li Shunzhi Li Bin Liang Graduate School at Shenzhen Tsinghua University Shenzhen Laboratory of Space Robotics & Telescience Shenzhen Engineering Laboratory of Geometry Measurement Technology

For on-orbit servicing of large valuable satellite, docking ring is a typical and strong component, which is fit for grasping by a space robot manipulator. In this paper, a novel method for measuring the relative pose of partial docking ring is proposed by introducing double-line structured light. Firstly, the double-line structured light vision measurement model is established. The model need only partial docking ring to compute pose. Secondly, the pose determination algorithm is presented. Using the four intersection points between the double-line structured light and partial docking ring, the position and attitude of the docking ring can be uniquely determined. Finally, the mathematical simulation model is built and the measurement error factors are analyzed. The simulation results show that the measurement method is effective and feasible.

关键词： Pose measurement Partial docking ring Double-line structured light Non-cooperative target Space intelligent robot

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Effect of confinement on anharmonic phonon scattering and thermal conductivity in pristine silicon nanowires

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Physical Review B 2018年第7期97卷 075441-075441页

作者： Zahid Rashid Liyan Zhu Wu Li Institute for Advanced Study Shenzhen University Nanhai Avenue 3688 Shenzhen 518060 People's Republic of China Key Laboratory of Optoelectronic Devices and Systems of the Ministry of Education of Guangdong Province College of Optoelectronics Engineering Shenzhen University 518060 Shenzhen People's Republic of China School of Physics and Electronic and Electrical Engineering and Jiangsu Key Construction Laboratory of Modern Measurement Technology and Intelligent Systems Huaiyin Normal University Huai'an Jiangsu 223300 China

The effect of confinement on the anharmonic phonon scattering rates and the consequences thereof on the thermal transport properties in ultrathin silicon nanowires with a diameter of 1–4 nm have been characterized using atomistic simulations and the phonon Boltzmann transport equation. The phonon density of states (PDOS) for ultrathin nanowires approaches a constant value in the vicinity of the Γ point and increases with decreasing diameter, which indicates the increasing importance of the low-frequency phonons as heat carriers. The anharmonic phonon scattering becomes dramatically enhanced with decreasing thickness of the nanowires. In the thinnest nanowire, the scattering rates for phonons above 1 THz are one order of magnitude higher than those in the bulk Si. Below 1 THz, the increase in scattering rates is even much more appreciable. Our numerical calculations revealed that the scattering rates for transverse (longitudinal) acoustic modes follow ω (1/ω) dependence at the low-frequency limit, whereas those for the degenerate flexural modes asymptotically approach a constant value. In addition, the group velocities of phonons are reduced compared with bulk Si except for low-frequency phonons (<1–2 THz depending on the thickness of the nanowires). The increased scattering rates combined with reduced group velocities lead to a severely reduced thermal conductivity contribution from the high-frequency phonons. Although the thermal conductivity contributed by those phonons with low frequencies is instead increased mainly due to the increased PDOS, the total thermal conductivity is still reduced compared to that of the bulk. This work reveals an unexplored mechanism to understand the measured ultralow thermal conductivity of silicon nanowires.

关键词： Thermal conductivity Nanowires Boltzmann theory

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Benchmarking the CoW with the TopCoW Challenge: Topology-Aware Anatomical Segmentation of the Circle of Willis for CTA and MRA

arXiv

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arXiv 2023年

作者： Yang, Kaiyuan Musio, Fabio Ma, Yihui Juchler, Norman Paetzold, Johannes C. Al-Maskari, Rami Höher, Luciano Li, Hongwei Bran Hamamci, Ibrahim Ethem Sekuboyina, Anjany Shit, Suprosanna Huang, Houjing Prabhakar, Chinmay de la Rosa, Ezequiel Waldmannstetter, Diana Kofler, Florian Navarro, Fernando Menten, Martin Ezhov, Ivan Rueckert, Daniel Vos, Iris Ruigrok, Ynte Velthuis, Birgitta Kuijf, Hugo Hämmerli, Julien Wurster, Catherine Bijlenga, Philippe Westphal, Laura Bisschop, Jeroen Colombo, Elisa Baazaoui, Hakim Makmur, Andrew Hallinan, James Wiestler, Bene Kirschke, Jan S. Wiest, Roland Montagnon, Emmanuel Letourneau-Guillon, Laurent Galdran, Adrian Galati, Francesco Falcetta, Daniele Zuluaga, Maria A. Lin, Chaolong Zhao, Haoran Zhang, Zehan Ra, Sinyoung Hwang, Jongyun Park, Hyunjin Chen, Junqiang Wodzinski, Marek Müller, Henning Shi, Pengcheng Liu, Wei Ma, Ting Yalçin, Cansu Hamadache, Rachika E. Salvi, Joaquim Llado, Xavier Estrada, Uma Maria Lal-Trehan Abramova, Valeriia Giancardo, Luca Oliver, Arnau Liu, Jialu Huang, Haibin Cui, Yue Lin, Zehang Liu, Yusheng Zhu, Shunzhi Patel, Tatsat R. Tutino, Vincent M. Orouskhani, Maysam Wang, Huayu Mossa-Basha, Mahmud Zhu, Chengcheng Rokuss, Maximilian R. Kirchhoff, Yannick Disch, Nico Holzschuh, Julius Isensee, Fabian Maier-Hein, Klaus Sato, Yuki Hirsch, Sven Wegener, Susanne Menze, Bjoern Department of Quantitative Biomedicine University of Zurich Zurich Switzerland Center for Computational Health Zurich University of Applied Sciences Zurich Switzerland Department of Neuroradiology University Hospital of Zurich Zurich Switzerland Department of Neurosurgery Zhongnan Hospital of Wuhan University Wuhan China Department of Computing Imperial College London London United Kingdom Helmholtz Center Munich Germany Athinoula A. Martinos Center for Biomedical Imaging Harvard Medical School Boston United States School of Medicine Technical University of Munich Munich Germany Department of Informatics Technical University of Munich Munich Germany Helmholtz AI Helmholtz Munich Munich Germany Image Sciences Institute UMC Utrecht Utrecht Netherlands Department of Neurology UMC Utrecht Utrecht Netherlands Department of Radiology UMC Utrecht Utrecht Netherlands Department of Clinical Neurosciences Division of Neurosurgery Geneva University Hospitals Geneva Switzerland Department of Neurology University Hospital of Zurich Zurich Switzerland Department of Physiology University of Toronto Toronto Canada Department of Neurosurgery University Hospital of Zurich Zurich Switzerland Department of Diagnostic Imaging National University Hospital Singapore Department of Diagnostic and Interventional Neuroradiology University Hospital Berne University of Berne Berne Switzerland Montreal Canada Universitat Pompeu Fabra Barcelona Spain EURECOM Biot France Institute of Medical Technology Peking University Health Science Center Beijing China Hangzhou Genlight Medtech Co. Ltd. Hangzhou China Department of Artificial Intelligence Sungkyunkwan University Seoul Korea Republic of Department of Electrical and Computer Engineering Sungkyunkwan University Seoul Korea Republic of Shanghai MediWorks Precision Instruments Co. Ltd. Shanghai China Institute of Informatics HES-SO Valais-Wallis Switzerland Department of Measurement and Electronics AGH University

The Circle of Willis (CoW) is an important network of arteries connecting major circulations of the brain. Its vascular architecture is believed to affect the risk, severity, and clinical outcome of serious neuro-vascular diseases. However, characterizing the highly variable CoW anatomy is still a manual and time-consuming expert task. The CoW is usually imaged by two angiographic imaging modalities, magnetic resonance angiography (MRA) and computed tomography angiography (CTA), but there exist limited public datasets with annotations on CoW anatomy, especially for CTA. Therefore we organized the TopCoW Challenge in 2023 with the release of an annotated CoW dataset. The TopCoW dataset was the first public dataset with voxel-level annotations for thirteen possible CoW vessel components, enabled by virtual-reality (VR) technology. It was also the first large dataset with paired MRA and CTA from the same patients. TopCoW challenge formalized the CoW characterization problem as a multiclass anatomical segmentation task with an emphasis on topological metrics. We invited submissions worldwide for the CoW segmentation task, which attracted over 140 registered participants from four continents. The top performing teams managed to segment many CoW components to Dice scores around 90%, but with lower scores for communicating arteries and rare variants. There were also topological mistakes for predictions with high Dice scores. Additional topological analysis revealed further areas for improvement in detecting certain CoW components and matching CoW variant topology accurately. TopCoW represented a first attempt at benchmarking the CoW anatomical segmentation task for MRA and CTA, both morphologically and topologically. © 2023, CC BY-NC-ND.

关键词： Large datasets

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