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THE decay OF SWIRLING FLOWS IN A TYPE OF CROSS-SECTION-VARYING PIPES

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Applied Mathematics and Mechanics(English Edition) 2001年第8期22卷 983-988页

作者： XIONG Ao-kui(熊鳌魁) WEI Qing-ding(魏庆鼎) Department of Mechanics and Engineering Science Peking UniversityBeijing 100871 P R China Department of Mechanics and Engineering Science Peking UniversityBeijing 100871 P R China

The decay of weakly swirling flows in a type of cross-section-varying pipes was discussed analytically. For laminar swirling flow, the feature of exponential decay was demonstrated. For turbulent swirling flow, in spite of the decay of circulation flux, a necessary condition for local circulation to amplify along downstream was obtained under the Boussinesq's hypothesis.

关键词： swirling flow decay analysis of fluid flows

Enhanced monopole transition strength from the cluster decay of ^(13)C

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Science China(Physics,Mechanics & Astronomy) 2019年第1期62卷 49-55页

作者： Jun Feng YanLin Ye Biao Yang ChengJian Lin HuiMin Jia DanYang Pang ZhiHuan Li JianLing Lou QiTe Li XiaoFei Yang Jing Li HongLiang Zang Qiang Liu Wei Jiang ChenGuang Li Yang Liu ZhiQiang Chen HongYi Wu ChunGuang Wang Wei Liu Xiang Wang JingJing Li DiWen Luo Ying Jiang ShiWei Bai JinYan Xu NanRu Ma LiJie Sun DongXi Wang School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University China Institute of Atomic Energy School of Physics and Nuclear Energy Engineering Beihang University Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang University

The inelastic excitations and cluster decay of ^(13)C have been measured using the reaction,9Be(^(13)C, ^(13)C* →~9Be + α)~9Be. We observe strong excitation to the 14.3-MeV(1/2-) resonant state from the cluster-decay channel, leading to an enhanced monopole matrix element of(6.3 ± 0.6) fm^2. This large cluster-related monopole strength is a clear indication of the cluster-structure domination of this state and is consistent with the recent prediction of the orthogonality condition model(OCM). It would be interesting to further explore the three-center molecular rotational band that is initiated from the observed band-head.

关键词： inelastic excitation monopole transition cluster decay

decay ESTIMATE AND GLOBAL EXISTENCE OF SEMILINEAR THERMOELASTIC TIMOSHENKO SYSTEM WITH TWO DAMPING EFFECTS

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Acta Mathematica Scientia 2019年第6期39卷 1461-1486页

作者： Weike WANG Rui XUE School of Mathematical Sciences&Institute of Natural Sciences Shanghai Jiao Tong UniversityShanghai 200240China School of Mathematical Sciences Shanghai Jiao Tong UniversityShanghai 200240China

In this paper, we study a semilinear Timoshenko system with heat conduction having two damping effects. The observation that two damping effects might lead to smaller decay rates for solutions in comparison to one damping effect is rigorously proved here in providing optimality results. Moreover, the global well-posedness for small data is presented.

关键词： semilinear Timoshenko system heat conduction damping optimal decay rate eigenvalue expansion method

Supercurrent decay in ballistic magnetic Josephson junctions

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npj Computational Materials 2022年第1期8卷 186-196页

作者： HervéNess Ivan A.Sadovskyy Andrey E.Antipov Mark van Schilfgaarde Roman M.Lutchyn Department of Physics King’s College LondonStrand CampusLondonWC2R 2LSUK Microsoft Quantum Microsoft Station QUniversity of CaliforniaSanta BarbaraCA93106USA National Renewable Energy Laboratory GoldenCO80401USA

We investigate transport properties of ballistic magnetic Josephson junctions and establish that suppression of supercurrent is an intrinsic property of the junctions,even in absence of *** studying the role of ferromagnet thickness,magnetization,and crystal orientation we show how the supercurrent decays exponentially with thickness and identify two mechanisms responsible for the effect:(i)large exchange splitting may gap out minority or majority carriers leading to the suppression of Andreev reflection in the junction,(ii)loss of synchronization between different modes due to the significant dispersion of the quasiparticle velocity with the transverse *** results for Nb/Ni/Nb junctions are in good agreement with recent experimental *** approach combines density functional theory and the Bogoliubov-de Gennes model and opens a path for material composition optimization in magnetic Josephson junctions and superconducting magnetic spin valves.

关键词： Josephson decay magnetic

Search for the lepton favor violating decay J/ψ→eμ

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Science China(Physics,Mechanics & Astronomy) 2023年第2期66卷 24-33页

作者： BESII Collaboratio Institute of High Energy Physics Beijing China G.I. Budker Institute of Nuclear Physics SB RAS (BINP) Novosibirsk Russia Also at the Novosibirsk State University Novosibirsk Russia Uppsala University Uppsala Sweden Bochum Ruhr-University Bochum Germany Johannes Gutenberg University of Mainz Mainz Germany University of Turin and INFN University of Turin Turin Italy University of Turin and INFN INFN Turin Italy Liaoning Normal University Dalian China University of Science and Technology of China Hefei China State Key Laboratory of Particle Detection and Electronics Beijing China State Key Laboratory of Particle Detection and Electronics Hefei China University of Jinan Jinan China Southeast University Nanjing China Joint Institute for Nuclear Research Dubna Moscow region Russia INFN Laboratori Nazionali di Frascati INFN Laboratori Nazionali di Frascati Frascati Italy INFN Sezione di Ferrara INFN Sezione di Ferrara Ferrara Italy Peking University Beijing China Also at State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China National Centre for Nuclear Research Warsaw Poland Institute of Physics and Technology Ulaanbaatar Mongolia University of Muenster Muenster Germany Carnegie Mellon University Pittsburgh USA Wuhan University Wuhan China University of Chinese Academy of Sciences Beijing China Turkish Accelerator Center Particle Factory Group Istinye University Istanbul Turkey Also at the Moscow Institute of Physics and Technology Moscow Russia Nankai University Tianjin China Soochow University Suzhou China Nanjing University Nanjing China Tsinghua University Beijing China Institute of Modern Physics Lanzhou China Hunan University Changsha China Also at School of Physics and Electronics Hunan University Changsha China Shandong University Jinan China Yunnan University Kunming China Helmholtz Institute Mainz Mainz Germany Liaoning University Shenyang China Zhengzhou University Zhengzhou China University o

We present a search for the lepton flavor violating decay J/ψ→e±μ?using 8.998×109J/ψevents collected with the BESⅢdetector at the BEPCⅡe+e-storage *** excess of signal above background is observed;we therefore set an upper limit on the branching fraction of B(J/ψ→e±μ?)<4.5×10-9at the 90%confidence *** the previous best result by a factor of more than 30,this measurement places the most stringent limit to date on lepton flavor violation in the heavy quarkonium sector.

关键词： BESⅢ decay limit

Free-radical evolution and decay in cross-linked polytetrafluoroethylene irradiated by gamma-rays

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Nuclear Science and Techniques 2022年第5期33卷 113-125页

作者： Fei-Xiang Sha Guo-Jun Cheng Zi-Yue Xuan Yang Liu Wei-Hua Liu Xiao-Dong Zhang Zhong-Feng Tang School of Materials Science and Engineering Anhui University of Science and TechnologyHuainan 232000China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China National Key Laboratory of Materials Behavior and Evaluation Technology in Space Environment Harbin Institute of TechnologyHarbin 150001China University of Chinese Academy of Sciences Beijing 100049China

Electron spin resonance techniques were employed to investigate the effects of the absorbed dose and post-irradiation conditions on the evolution and decay of free-radicals in cross-linked polytetrafluoroethylene(XPTFE),induced byγ-ray ***-end free-radicals,chain alkyl free-radicals,and tertiary alkyl free-radicals were detected when XPTFE was irradiated under Ar *** corresponding peroxy free-radicals were formed upon exposure of irradiated XPTFE to air;the freeradicals concentration first increased linearly with increasing absorbed dose and then gradually *** free-radicals yield under air atmosphere was greater than that under Ar,and the peroxy free-radicals were preserved for a relatively long time when irradiated XPTFE was stored under air *** chain alkyl free-radicals may be converted to chain end free-radicals byβ-scission,while chain end free-radicals are more sensitive to oxygen than chain alkyl *** the annealing temperature was raised above the a-transition temperature of XPTFE,the decay of the free-radicals was greatly affected and accelerated by the motion of the molecules over the long range.

关键词： Polytetrafluoroethylene Cross-linked polytetrafluoroethylene Electron spinresonance decay Radiation c-ray

Single-emitter super-resolved imaging of radiative decay rate enhancement in dielectric gap nanoantennas

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Light(Science & Applications) 2024年第1期13卷 47-54页

作者： R.Margoth Córdova-Castro Bart van Dam Alberto Lauri Stefan A.Maier Riccardo Sapienza Yannick De Wilde Ignacio Izeddin Valentina Krachmalnicoff Institut Langevin ESPCI ParisPSL UniversityCNRSParisFrance The Blackett Laboratory Department of PhysicsImperial College LondonLondonUK School of Physics and Astronomy Monash UniversityClaytonVictoriaAustralia Chair in Hybrid Nanosystems Ludwig-Maximilians Universität MünchenMuenchenGermany Department of Physics University of OttawaOttawaONCanada

High refractive index dielectric nanoantennas strongly modify the decay rate via the Purcell effect through the design of radiative *** to their dielectric nature,the field is mainly confined inside the nanostructure and in the gap,which is hard to probe with scanning probe *** we use single-molecule fluorescence lifetime imaging microscopy(smFLIM)to map the decay rate enhancement in dielectric GaP nanoantenna dimers with a median localization precision of 14 *** measure,in the gap of the nanoantenna,decay rates that are almost 30 times larger than on a glass *** comparing experimental results with numerical simulations we show that this large enhancement is essentially radiative,contrary to the case of plasmonic nanoantennas,and therefore has great potential for applications such as quantum optics and biosensing.

关键词： dielectric decay radiative

Upconversion FRET quantitation:the role of donor photoexcitation mode and compositional architecture on the decay and intensity based responses

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Light(Science & Applications) 2022年第10期11卷 2321-2334页

作者： Agata Mkotulska Aleksandra Pilch-WrÓbel Satu Lahtinen Tero Soukka Artur Bednarkiewicz Division of Biomedical Physicochemistry Institute of Low Temperature and Structure ResearchPANul.Okolna 2Wroclaw 50-422Poland Department of Life Technologies/Biotechnology University of TurkuKiinamyllynkatu 1020520 TurkuFinland

Lanthanide-doped colloidal nanoparticles capable of photon upconversion(UC)offer long luminescence lifetimes,narrowband absorption and emission spectra,and efficient anti-Stokes *** features are highly advantageous for F?rster Resonance Energy Transfer(FRET)based *** nanoparticles(UCNPs)as donors may solve the existing problems of molecular FRET systems,such as photobleaching and limitations in quantitative analysis,but these new labels also bring new *** we have studied the impact of the core-shell compositional architecture of upconverting nanoparticle donors and the mode of photoexcitation on the performance of UC-FRET from UCNPs to Rose Bengal(RB)molecular *** have quantitatively compared luminescence rise and decay kinetics of Er3+emission using core-only NaYF4:20%Yb,2%Er and core-shell NaYF4:20%Yb@NaYF4:20%Yb,5%Er donor UCNPs under three photoexcitation schemes:(1)direct short-pulse photoexcitation of Er3+at 520 nm;indirect photoexcitation of Er3+through Yb3+sensitizer with(2)980 nm short(5-7 ns)or(3)980 nm long(4 ms)laser *** donor luminescence kinetics and steady-state emission spectra differed between the UCNP architectures and excitation *** for highly sensitive kinetic upconversion FRET-based biomolecular assays,the experimental results underline the complexity of the excitation and energy-migration mechanisms affecting the Er3+donor responses and suggest ways to optimize the photoexcitation scheme and the architecture of the UCNPs used as luminescent donors.

关键词： excitation donor decay

Bacterial succession in epiphytic biofilms and deciduous layer sediments during Hydrilla verticillata decay: A field investigation

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Journal of Environmental Sciences 2020年第7期32卷 193-201页

作者： Tingting Si Hezhou Chen Zheng Qiu Lisha Zhang Okugbe Ebiotubo Ohore Songhe Zhang Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes College

Submersed macrophytes decay is an important natural process and has important role in mass and energy flow in aquatic ***,little is known about the dynamical changes in nutrients release and bacterial community during submersed macrophyte decay in natural *** this study,a field observation was conducted in a wetland dominated with Hydrilla verticillata for 36 *** of H2O2 and malondialdehyde(MDA)content and decrease of soluble proteins concentration were detected in leaves during *** ***,ammonium-N,soluble microbial products(SMP)and TOC concentration increased in overlying *** to bacterial 16 S r RNA Illumina sequencing analysis,the Shannon values were lower in epiphytic biofilms than deciduous layer *** relative abundances of Proteobacteria,Cyanobacteria and Actinobacteria were higher in epiphytic biofilms than in deciduous layer sediments(P0.6)were identified from 122 and 112 genera in epiphytic biofilms and deciduous layer sediments,*** to co-occurrence patterns,eight hubs were mainly from phyla Proteobacteria,Acidobacteria and Parcubacteria in epiphytic biofilms;while 37 hubs from the 14 phyla(Proteobacteria,Bacteroidetes,Acidobacteria,Chloroflexi,et al.)were detected in deciduous layer *** results indicate that bacterial community in deciduous layer sediments was more susceptible than in epiphytic biofilms during decay *** data highlight the role of microbial community in deciduous layer sediments on nutrients removal during *** decay and will provide useful information for wetland management.

关键词： Submersed macrophyte decay Biofilm Bacterial community Co-occurrence network