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Electron-Phonon Coupling Suppression by Enhanced Lattice Rigidity in 2D Perovskite Single Crystals for High-Performance X-Ray Detection

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Advanced materials (Deerfield Beach, Fla.) 2023年第7期35卷 e2208875页

作者： Bobo Zhang Tao Zheng Jiaxue You Chuang Ma Yucheng Liu Lu Zhang Jun Xi Guohua Dong Ming Liu Shengzhong Frank Liu Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy Technology International Joint Research Center of Shaanxi Province for Photoelectric Materials Science Institute for Advanced Energy Materials School of Materials Science and Engineering Shaanxi Normal University Xi'an 710119 China. State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China. Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique School of Electronic Science and Engineering Xi'an Jiaotong University No. 28 Xianning West Road Xi'an 710049 China. The Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education & International Center for Dielectric Research School of Electronic Science and Engineering State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an 710049 China. Dalian National Laboratory for Clean Energy iChEM Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China. University of the Chinese Academy of Sciences Beijing 100039 China.

2D Dion-Jacobson (DJ) perovskite single crystals (PSCs) usually demonstrate better X-ray detection performance than Ruddlesden-Popper (RP) PSCs. However, the mechanism of the improved performance is still elusive. Here, by the aid of strong interactions between dimethylbiguanide (DGA) and PbI , a novel DJ-perovskitoid (DGA)PbI is designed. From the comparison of (DGA)PbI to other 2D PSCs, it is discovered that the tiniest lattice distortion and increased hydrogen bonds in the atom-scaled analysis strengthen lattice rigidity and weaken electron-phonon coupling to suppress disordered scattering of carriers, resulting in significantly improved carrier transport and stability. Therefore, high carrier mobility (78.1 cm V s ) and a pronounced sensitivity of 4869.0 µC Gy cm are achieved using (DGA)PbI , which are the best in 2D Pb-based PSC devices to date. Finally, the (DGA)PbI devices exhibit good spatial resolution in X-ray imaging and excellent long-term stability to work as a promising candidate for medical diagnostics and nondestructive determination.

关键词： 2D perovskite X-ray detection electron-phonon coupling high sensitivity lattice rigidity

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Deep learning for depression recognition with audiovisual cues: A review

arXiv

引用

arXiv 2021年

作者： He, Lang Niu, Mingyue Tiwari, Prayag Marttinen, Pekka Su, Rui Jiang, Jiewei Guo, Chenguang Wang, Hongyu Ding, Songtao Wang, Zhongmin Pan, Xiaoying Dang, Wei School of Computer Science and Technology Xi'an University of Posts and Telecommunications Shaanxi Xi'an710121 China Shaanxi Key Laboratory of Network Data Analysis and Intelligent Processing Xi'an University of Posts and Telecommunications Shaanxi Xi'an710121 China Beijing100190 China Beijing100049 China Department of Computer Science Aalto University Espoo Finland School of Foreign Languages Northwest University Shaanxi Xi'an China School of Electronic Engineering Xi'an University of Posts and Telecommunications Xi'an China School of Electronics and Information Northwestern Polytechnical University Shaanxi Xi'an China Shaanxi Mental Health Center Shaanxi Xi'an710061 China

With the acceleration of the pace of work and life, people have to face more and more pressure, which increases the possibility of suffering from depression. However, many patients may fail to get a timely diagnosis due to the serious imbalance in the doctor-patient ratio in the world. Promisingly, physiological and psychological studies have indicated some differences in speech and facial expression between patients with depression and healthy individuals. Consequently, to improve current medical care, many scholars have used deep learning to extract a representation of depression cues in audio and video for automatic depression detection. To sort out and summarize these works, this review introduces the databases and describes objective markers for automatic depression estimation (ADE). Furthermore, we review the deep learning methods for automatic depression detection to extract the representation of depression from audio and video. Finally, this paper discusses challenges and promising directions related to automatic diagnosing of depression using deep learning technologies. © 2021, CC BY.

关键词： Diagnosis

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Deformation-Enhanced Hierarchical Multiscale Structure Heterogeneity in a Pd-Si Bulk Metallic Glass

SSRN

引用

SSRN 2020年

作者： Wang, Lifeng Liu, Sinan Ge, Jiacheng Wu, Zhenduo Sun, Baoan Feng, Tao Wu, Yuan Wang, Jing Tao Hahn, Horst Wang, Xun-Li Lan, Si Herbert Gleiter Institute of Nanoscience Nanjing University of Science and Technology Nanjing210094 China Department for Physics City University of Hong Kong 83 Tat Chee Avenue Kowloon Hong Kong Institute of Physics Chinese Academy of Sciences Beijing100190 China Songshan Lake Materials Laboratory Guangdong Dongguan523808 China State Key Laboratory for Advance Metals and Materials University of Science and Technology Beijing Beijing10083 China Eggenstein-Leopoldshafen 76344 Germany Shenzhen Research Institute

The multiscale structures in a Pd82Si18 binary bulk metallic glass before and after bending were studied using electron microscopy, high-energy synchrotron X-ray diffraction, and small-angle X-ray scattering. The experimental results revealed the enhancement of hierarchical structure heterogeneities on multiple length scales after deformation. Hierarchical multiple shear bands of high number density can be observed after bending, introducing complex but periodically distributed residual strain. Pair distribution function analysis revealed that the connectivity of the short-range cluster on the medium-range scale determines the packing density difference between the tension side and the compression side in the sample after bending. The electron density fluctuations on the nanoscale observed in the deformed part of the sample are indicative of a nanoscale amorphous phase separation induced by plastic deformation. Our findings will deepen the understanding of the plastic deformation mechanism of metallic glasses and shed light on designing glassy alloys of excellent plasticity and toughness through hierarchical multiscale structure heterogeneities. © 2020, The Authors. All rights reserved.

关键词： Strain hardening

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Effective magnetic Hamiltonian at finite temperatures for rare earth chalcogenides

arXiv

引用

arXiv 2020年

作者： Zhang, Zheng Li, Jianshu Liu, Weiwei Zhang, Zhitao Ji, Jianting Jin, Feng Chen, Rui Wang, Junfeng Wang, Xiaoqun Ma, Jie Zhang, Qingming Department of Physics Renmin University of China Beijing100872 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory Chinese Academy of Sciences Hefei230031 China Wuhan National High Magnetic Field Center School of Physics Huazhong University of Science and Technology Wuhan430074 China Department of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China School of Physical Science and Technology Lanzhou University Lanzhou730000 China

Alkali metal rare-earth chalcogenide ARECh2 (A=alkali or monovalent metal, RE=rare earth, Ch=O, S, Se, Te), is a large family of quantum spin liquid (QSL) candidates we discovered recently. Unlike YbMgGaO4, most members in the family except for the oxide ones, have relatively small crystalline electric-field (CEF) excitation levels, particularly the first ones. This makes the conventional Curie-Weiss analysis at finite temperatures inapplicable and CEF excitations may play an essential role in understanding the low-energy spin physics. Here we considered an effective magnetic Hamiltonian incorporating CEF excitations and spin-spin interactions, to accurately describe thermodynamics in such a system. By taking NaYbSe2 as an example, we were able to analyze magnetic susceptibility, magnetization under pulsed high fields and heat capacity in a systematic and comprehensive way. The analysis allows us to produce accurate anisotropic exchange coupling energies and unambiguously determine a crossover temperature (∼25 K in the case of NaYbSe2), below which CEF effects fade away and pure spin-spin interactions stand out. We further validated the effective picture by successfully explaining the anomalous temperature dependence of electron spin resonance (ESR) spectral width. The effective scenario in principle can be generalized to other rare-earth spin systems with small CEF excitations. © 2020, CC BY.

关键词： Hamiltonians

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Observations of the Very Young Type Ia Supernova 2019np with Early-excess Emission

arXiv

引用

arXiv 2022年

作者： Sai, Hanna Wang, Xiaofeng Elias-Rosa, Nancy Yang, Yi Zhang, Jujia Lin, Weili Mo, Jun Piro, Anthony L. Zeng, Xiangyun Andrea, Reguitti Brown, Peter Burns, Christopher R. Cai, Yongzhi Fiore, Achille Hsiao, Eric Y. Isern, Jordi Itagaki, K. Li, Wenxiong Li, Zhitong Pessi, Priscila J. Phillips, M.M. Schuldt, Stefan Shahbandeh, Melissa Stritzinger, Maximilian D. Tomasella, Lina Vogl, Christian Wang, Bo Wang, Lingzhi Wu, Chengyuan Yang, Sheng Zhang, Jicheng Zhang, Tianmeng Zhang, Xinghan Tsinghua University Beijing100084 China Beijing Planetarium Beijing Academy of Science and Technology Beijing100044 China INAF - Osservatorio Astronomico di Padova Vicolo dell'Osservatorio 5 Padova35122 Italy Campus UAB Carrer de Can Magrans s/n Barcelona08193 Spain Department of Astronomy University of California BerkeleyCA94720-3411 United States Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Carnegie Observatories 813 Santa Barbara Street PasadenaCA91101 United States Center for Astronomy and Space Sciences China Three Gorges University Yichang443000 China Departamento de Ciencias Físicas Universidad Andrés Bello Avda. República 252 Santiago8320000 Chile Millennium Institute of Astrophysics Nuncio Monsenor Sótero Sanz 100 Providencia Santiago8320000 Chile George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy Texas A. & M. University 4242 TAMU College StationTX77843 United States Department of Physics Florida State University 77 Chieftan Way TallahasseeFL32306 United States c/Gran Capitá 2-4 Edif. Nexus 201 Barcelona08034 Spain Itagaki Astronomical Observatory Yamagata Yamagata990-2492 Japan The School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing101408 China Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Paseo del Bosque S/N La PlataB1900FWA Argentina Carnegie Observatories Las Campanas Observatory Colina El Pino Casilla 601 Chile Max-Planck-Institut für Astrophysik Karl-Schwarzschild Str. 1 G

Early-time radiative signals from type Ia supernovae (SNe Ia) can provide important constraints on the explosion mechanism and the progenitor system. We present observations and analysis of SN 2019np, a nearby SN Ia discovered within 1-2 days after the explosion. Follow-up observations were conducted in optical, ultraviolet, and near-infrared bands, covering the phases from ∼ −16.7 days to ∼+367.8 days relative to its B−band peak luminosity. The photometric and spectral evolutions of SN 2019np resembles the average behavior of normal SNe Ia. The absolute B-band peak magnitude and the post-peak decline rate are Mmax(B) =−19.52 ± 0.47 mag and ∆m15(B) =1.04±0.04 mag, respectively. No Hydrogen line has been detected in the near-infrared and nebular-phase spectra of SN 2019np. Assuming that the 56Ni powering the light curve is centrally located, we find that the bolometric light curve of SN 2019np shows a flux excess up to 5.0% in the early phase compared to the radiative diffusion model. Such an extra radiation perhaps suggests the presence of an additional energy source beyond the radioactive decay of central nickel. Comparing the observed color evolution with that predicted by different models such as interactions of SN ejecta with circumstellar matter (CSM)/companion star, a double-detonation explosion from a sub-Chandrasekhar mass white dwarf (WD), and surface 56Ni mixing, the latter one is favored. © 2022, CC BY.

关键词： Supernovae

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Fungal diversity notes 1387-1511:taxonomic and phylogenetic contributions on genera and species of fungal taxa

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Fungal Diversity 2021年第6期111卷 1-335页

作者： Saranyaphat Boonmee Dhanushka N.Wanasinghe Mark S.Calabon Naruemon Huanraluek Sajini K.U.Chandrasiri Gareth E.B.Jones Walter Rossi Marco Leonardi Sanjay K.Singh Shiwali Rana Paras N.Singh Deepak K.Maurya Ajay C.Lagashetti Deepika Choudhary Yu-Cheng Dai Chang-Lin Zhao Yan-Hong Mu Hai-Sheng Yuan Shuang-Hui He Rungtiwa Phookamsak Hong-Bo Jiang María P.Martín Margarita Dueñas MTeresa Telleria Izabela L.Kałucka Andrzej M.Jagodziński Kare Liimatainen Diana S.Pereira Alan J.L.Phillips Nakarin Suwannarach Jaturong Kumla Surapong Khuna Saisamorn Lumyong Tarynn B.Potter Roger G.Shivas Adam H.Sparks Niloofar Vaghefi Mohamed A.Abdel-Wahab Faten A.Abdel-Aziz Guo-Jie Li Wen-Fei Lin Upendra Singh Rajendra P.Bhatt Hyang Burm Lee Thuong T.T.Nguyen Paul M.Kirk Arun Kumar Dutta Krishnendu Acharya VVenkateswara Sarma M.Niranjan Kunhiraman C.Rajeshkumar Nikhil Ashtekar Sneha Lad Nalin N.Wijayawardene Darbe J.Bhat Rong-Ju Xu Subodini N.Wijesinghe Hong-Wei Shen Zong-Long Luo Jing-Yi Zhang Phongeun Sysouphanthong Naritsada Thongklang Dan-Feng Bao Janith V.S.Aluthmuhandiram Jafar Abdollahzadeh Alireza Javadi Francesco Dovana Muhammad Usman Abdul Nasir Khalid Asha J.Dissanayake Anusha Telagathoti Maraike Probst Ursula Peintner Isaac Garrido-Benavent Lilla Bóna Zsolt Merényi Lajos Boros Bratek Zoltán JBenjamin Stielow Ning Jiang Cheng-Ming Tian Esmaeil Shams Farzaneh Dehghanizadeh Adel Pordel Mohammad Javan-Nikkhah Teodor T.Denchev Cvetomir M.Denchev Martin Kemler Dominik Begerow Chun-Ying Deng Emma Harrower Tohir Bozorov Tutigul Kholmuradova Yusufjon Gafforov Aziz Abdurazakov Jian-Chu Xu Peter E.Mortimer Guang-Cong Ren Rajesh Jeewon Sajeewa S.N.Maharachchikumbura Chayanard Phukhamsakda Ausana Mapook Kevin D.Hyde Center of Excellence in Fungal Research Mae Fah Luang UniversityChiang Rai 57100Thailand School of Science Mae Fah Luang UniversityChiang Rai 57100Thailand CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia(KLPB) Kunming Institute of BotanyChinese Academy of ScienceKunming 650201YunnanPeople’s Republic of China CIFOR-ICRAF China Program World Agroforestry(ICRAF)Kunming 650201YunnanPeople’s Republic of China Honghe Center for Mountain Futures Kunming Institute of BotanyHonghe CountyKunming 654400YunnanPeople’s Republic of China Department of Botany and Microbiology College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia Section Environmental Sciences Department MeSVAUniversity of L’Aquila67100 CoppitoAQItaly National Fungal Culture Collection of India(NFCCI) Biodiversity and Palaeobiology GroupMACS Agharkar Research InstituteG.G.Agarkar RoadPune 411004India Institute of Microbiology School of Ecology and Nature ConservationBeijing Forestry UniversityBeijing 100083People’s Republic of China College of Biodiversity Conservation Southwest Forestry UniversityKunming 650224People’s Republic of China CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110164People’s Republic of China University of the Chinese Academy of Sciences Beijing 100049People’s Republic of China Centre for Mountain Futures(CMF) Kunming Institute of BotanyKunming 650201YunnanPeople’s Republic of China Department of Mycology Real Jardín Botánico-CSICPlaza de Murillo 228014 MadridSpain Department of Algology and Mycology Faculty of Biology and Environmental ProtectionUniversity of LodzBanacha 12/1690-237ŁódźPoland Institute of Dendrology Polish Academy of SciencesParkowa 562-035 KórnikPoland Jodrell Laboratory Royal Botanic GardensKewRichmond TW93DSSurreyUK Faculdade de Ciências Biosystems and Integrative Sciences Institute(BioISI)Universidade de LisboaCampo Grande1749-016 LisbonPortugal Dep

This article is the 13th contribution in the Fungal Diversity Notes series,wherein 125 taxa from four phyla,ten classes,31 orders,69 families,92 genera and three genera incertae sedis are treated,demonstrating worldwide and geographic *** taxa described and illustrated in the present study include three new genera,69 new species,one new com-bination,one reference specimen and 51 new records on new hosts and new geographical *** new genera,Cylindrotorula(Torulaceae),Scolecoleotia(Leotiales genus incertae sedis)and Xenovaginatispora(Lindomycetaceae)are introduced based on distinct phylogenetic lineages and unique *** described species are Aspergillus lan-naensis,Cercophora dulciaquae,Cladophialophora aquatica,Coprinellus punjabensis,Cortinarius alutarius,***-latus,***,Coryneum fagi,Cruentomycena uttarakhandina,Cryptocoryneum rosae,Cyathus uniperidiolus,Cylindrotorula indica,Diaporthe chamaeropicola,Didymella azollae,Diplodia alanphillipsii,Dothiora coronicola,Efibula rodriguezarmasiae,Erysiphe salicicola,Fusarium queenslandicum,Geastrum gorgonicum,***,Helicosporium sexualis,Helminthosporium chiangraiensis,Hongkongmyces kokensis,Hydrophilomyces hydraenae,Hygrocybe boertmannii,Hyphoderma australosetigerum,Hyphodontia yunnanensis,Khaleijomyces umikazeana,Laboulbenia divisa,Laboulbenia triarthronis,Laccaria populina,Lactarius pallidozonarius,Lepidosphaeria strobelii,Longipedicellata megafusiformis,Lophiotrema lincangensis,Marasmius benghalensis,***,***,Mariannaea camelliae,Mel-anographium smilaxii,Microbotryum polycnemoides,Mimeomyces digitatus,Minutisphaera thailandensis,Mortierella solitaria,Mucor harpali,Nigrograna jinghongensis,Odontia huanrenensis,***,Paraconiothyrium ajrekarii,Par-afuscosporella niloticus,Phaeocytostroma yomensis,Phaeoisaria synnematicus,Phanerochaete hainanensis,Pleopunctum thailandicum,Pleurotheciella dimorphospora,Pseudochaetosphaeronema

关键词： 72 new taxa One new combination One reference specimen 51 new records Agaricomycetes Ascomycota Bartheletiomycetes Basidiomycota Dothideomycetes Eurotiomycetes Exobasidiomycetes Laboulbeniomycetes Leotiomycetes Mortierellomycetes Mortierellomycota Mucoromycetes Mucoromycota Phylogeny Sordariomycetes Taxonomy

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Toward Complete Transformation of Sodium Polysulfides by Regulating the Second-Shell Coordinating Environment of Atomically Dispersed Fe

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Angewandte Chemie 2023年第26期135卷

作者： Ruilin Bai Qiaosong Lin Xinyu Li Fangxin Ling Huijuan Wang Sha Tan Lingxiang Hu Mingze Ma Prof. Xiaojun Wu Yu Shao Xianhong Rui Prof. Enyuan Hu Dr. Yu Yao Prof. Yan Yu Hefei National Research Center for Physical Sciences at the Microscale Department of Materials Science and Engineering CAS Key Laboratory of Materials for Energy Conversion University of Science and Technology of China Hefei Anhui 230026 China Contribution: Conceptualization (lead) Writing - original draft (lead) State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 Liaoning China University of Chinese Academy of Sciences Beijing 100049 China Contribution: Data curation (lead) Contribution: Formal analysis (equal) Contribution: Investigation (lead) Experimental Center of Engineering and Material Science University of Science and Technology of China Hefei 230026 China Contribution: Methodology (equal) Chemistry Division Brookhaven National Laboratory Upton NY USA Contribution: Resources (equal) Department of Electrical Engineering and Computer Science Institut Polytechnique de Paris 91120 Palaiseau Île-de-France France Contribution: Software (equal) Contribution: Data curation (equal) Jiujiang DeFu Technology Co. Ltd. Jiujiang Jiangxi 332000 (P. R. China School of Materials and Energy Guangdong University of Technology Guangzhou 510006 China Contribution: Validation (lead) Contribution: Methodology (lead) Contribution: Writing - review & editing (lead) National Synchrotron Radiation Laboratory Hefei Anhui 230026 China Contribution: Project administration (lead) Writing - review & editing (lead)

Room temperature sodium-sulfur (RT Na-S) batteries are highly competitive as potential energy storage devices. Nevertheless, their actually achieved reversible capacities are far below the theoretical value due to incomplete transformation of polysulfides. Herein, atomically dispersed Fe-N/S active center by regulating the second-shell coordinating environment of Fe single atom is proposed. The Fe−N 4 S 2 coordination structure with enhanced local electronic concentration around the Fermi level is revealed via synchrotron radiation X-ray absorption spectroscopy (XAS) and theoretical calculations, which can not only significantly promote the transformation kinetics of polysulfides, but induce uniform Na deposition for dendrite-free Na anode. As a result, the obtained S cathode delivers a high initial reversible capacity of 1590 mAh g −1 , nearly the theoretical value. This work opens up a new avenue to facilitate the complete transformation of polysulfides for RT Na-S batteries.

关键词： Catalysis Coordinating Environment Fe Single Atom RT Na-S Batteries Transformation Kinetics

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On-Chip Dual-Comb Source Based on Terahertz Quantum Cascade Lasers Under Microwave Double Injection

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Physical Review Applied 2019年第4期12卷 044068-044068页

作者： Ziping Li Wenjian Wan Kang Zhou Xiaoyu Liao Sijia Yang Zhanglong Fu J.C. Cao Hua Li Key Laboratory of Terahertz Solid State Technology Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences 865 Changning Road Shanghai 200050 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China

High-power and broadband dual-comb sources in the terahertz frequency regime are much in demand for fast and high-resolution spectroscopies. The terahertz quantum cascade laser (QCL) is a powerful radiation source in the frequency range between 1 and 5 THz, which is an ideal candidate for frequency-comb and dual-comb generations in this frequency regime. In this work, we report on broadband on-chip dual-comb sources based on terahertz QCLs emitting at approximately 4.2 THz with a single plasmon waveguide configuration. Due to the fast intersubband transitions in QCLs, the dual-comb lines can be detected by employing the laser self-detection scheme. A finite-element analysis shows that a weak optical coupling between the two laser combs is sufficient for generating dual-comb lines via the nonlinear multiheterodyne frequency beatings. The noise-equivalent power of the QCL detector is also evaluated for different optical powers; furthermore, a microwave double injection is employed to stabilize the comb frequency and broaden the optical comb bandwidth. We find that even with weak radio-frequency powers, the optical comb bandwidth can be significantly broadened from 86 to 166 GHz. The double injection also allows us to investigate the carrier offset noise of QCL combs.

关键词： Frequency combs & self-phase locking Optical sources & detectors Radio frequency techniques Quantum cascade lasers Waveguides Homodyne & heterodyne detection Terahertz techniques

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Training and testing Object Detectors With Virtual Images

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IEEE/CAA Journal of Automatica Sinica 2018年第2期5卷 539-546页

作者： Yonglin Tian Xuan Li Kunfeng Wang Fei-Yue Wang Department of Automation University of Science and Technology of China Hefei 230027 China State Key Laboratory for Management and Control of Complex Systems Institute of Automation Chinese Academy of Sciences Beijirtg 100190 China School of Automation Beijing Institute of Technology Beijing 100081. China Qingdao Academy of Intelligent Industries Qingdao 266000 China Research Center for Computational Experiments and Parallel Systems Technology National University of Defense Technology Changsha 410073 China IEEE

In the area of computer vision, deep learning has produced a variety of state-of-the-art models that rely on massive labeled data. However, collecting and annotating images from the real world is too demanding in terms of labor and money investments, and is usually inflexible to build datasets with specific characteristics, such as small area of objects and high occlusion level. Under the framework of Parallel Vision, this paper presents a purposeful way to design artificial scenes and automatically generate virtual images with precise annotations.A virtual dataset named Parallel Eye is built, which can be used for several computer vision tasks. Then, by training the DPM(Deformable parts model) and Faster R-CNN detectors, we prove that the performance of models can be significantly improved by combining Parallel Eye with publicly available real-world datasets during the training phase. In addition, we investigate the potential of testing the trained models from a specific aspect using intentionally designed virtual datasets, in order to discover the flaws of trained models. From the experimental results, we conclude that our virtual dataset is viable to train and test the object detectors.

关键词： Index Terms--Deep learning object detection parallel vision virtual dataset

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Results of 12 years of pulsar timing at nanshan - I

arXiv

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arXiv 2020年

作者： Dang, S.J. Yuan, J.P. Manchester, R.N. Li, L. Wang, N. Wang, J.B. Hobbs, G. Liu, Z.Y. Kou, F.F. XinJiang Astronomical Observatory Cas Urumqi XinJiang830011 China University of Chinese Academy of Sciences 19A Yuquan Road Beijing100049 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing210008 China Csiro Astronomy and Space Science Australia Telescope National Facility PO Box 76 EppingNSW1710 Australia School of Physics Science and Technology Xinjiang University Urumqi Xinjiang China Cas Key Laboratory of Fast National Astronomical Observatories Chinese Academy of Sciences Beijing China

We have used the Nanshan 25-m Radio Telescope at Xinjiang Astronomical Observatory to obtain timing observations of 87 pulsars from 2002 July to 2014 March. Using the "Cholesky" timing analysis method we have determined positions and proper motions for 48 pulsars, 24 of which are improved positions compared to previously published values. We also present the first published proper motions for nine pulsars and improved proper motions for 21 pulsars using pulsar timing and position comparison method. The pulsar rotation parameters are derived and are more accurate than previously published values for 36 pulsars. Glitches are detected in three pulsars: PSRs J1722-3632, J1852-0635 and J1957+2831. For the first two, the glitches are large, with Δνg/ν > 10-6, and they are the first detected glitches in these pulsars. PSR J1722-3632 is the second oldest pulsar with large glitch. For the middle-age pulsars (τc> 105yr), the calculated braking indices, |n|, are strongly correlated with τcand the numbers of positive and negative values of n are almost equal. For young pulsars (τc5yr), there is no correlation between |n| and τcand most have n > 0. Copyright © 2020, The Authors. All rights reserved.

关键词： Pulsars

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