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Ability to detect and locate gross errors on DEM matching algorithm

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International Journal of Digital Earth 2010年第1期3卷 72-82页

作者： T.Zhang M.Cen Z.Ren R.yang y.feng J.Zhu Department of Surveying Engineering School of Civil EngineeringSouthwest Jiaotong UniversityChengdu 610031China College of Earth Sciences Chengdu University of TechnologyChengdu 610051China

Digital elevation model(DEM)matching techniques have been extended to DEM deformation detection by substituting a robust estimator for the least squares estimator,in which terrain changes are treated as gross ***,all existing methods only emphasise their deformation detecting ability,and neglect another important aspect:only when the gross error can be detected and located,can this system be *** paper employs the gross error judgement matrix as a tool to make an in-depth analysis of this *** theoretical analyses and experimental results show that observations in the DEM matching algorithm in real applications have the ability to detect and locate gross ***,treating the terrain changes as gross errors is theoretically feasible,allowing real DEM deformations to be detected by employing a surface matching technique.

关键词： DEM matching gross error detection gross error location gross error judgement matrix least z-different algorithm deformation detection robust estimator

A new scale for optimized cryogenic magnetocaloric effect in ErAl_2@Al_2O_3 nanocapsules

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Journal of Materials Science & Technology 2018年第5期34卷 848-854页

作者： F.Wei S.Ma L.yang y.feng J.Z.Wang A.Hua X.G.Zhao D.y.Geng Z.D.Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge *** typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electron microscopy and X-ray photoelectron *** electron microscopy analysis shows the irregular sphere of the nanocapules with an average diameter of 26 *** investigation revealed the Curie temperature of Er Al2@Al2O3 nanocapsules at 20 K and the typical superparamagnetic behavior between blocking temperature and Curie *** on the blocking temperature and average diameter,the magnetocrystalline anisotropy constant of Er Al2@Al2O3nanocapsules was estimated to illustrate the magnetic contribution to *** large-SMof 14.25 J/（kg K）was obtained under 50 k Oe at 5 K.A vital parameter β was introduced in the present work to scale the optimized magnetic characteristics and the optimized mechanism was discussed in detail according to classical superparamagnetic *** results demonstrate that the optimal-SMwill be obtained when the magnetic parameter β is close to the theoretical coefficient.

关键词： Nanocapsules Magnetocaloric effect Superparamagnetic property Cryogenic refrigeration

Evidence for particle acceleration approaching PeV energies in the W51 complex

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Science Bulletin 2024年第18期69卷 2833-2841页

作者： LHAASO Collaboration Zhen Cao F.Aharonian Axikegu y.X.Bai y.W.Bao D.Bastieri X.J.Bi y.J.Bi W.Bian A.V.Bukevich Q.Cao W.y.Cao Zhe Cao J.Chang J.F.Chang A.M.Chen E.S.Chen H.X.Chen Liang Chen Lin Chen Long Chen M.J.Chen M.L.Chen Q.H.Chen S.Chen S.H.Chen S.Z.Chen T.L.Chen y.Chen N.Cheng y.D.Cheng M.y.Cui S.W.Cui X.H.Cui y.D.Cui B.Z.Dai H.L.Dai Z.G.Dai Danzengluobu X.Q.Dong K.K.Duan J.H.Fan y.Z.Fan J.Fang J.H.Fang K.Fang C.F.feng H.feng L.feng S.H.feng X.T.feng y.feng y.L.feng S.Gabici B.Gao C.D.Gao Q.Gao W.Gao W.K.Gao M.M.Ge L.S.Geng G.Giacinti G.H.Gong Q.B.Gou M.H.Gu F.L.Guo X.L.Guo y.Q.Guo y.y.Guo y.A.Han M.Hasan H.H.He H.N.He J.y.He y.He y.K.Hor B.W.Hou C.Hou X.Hou H.B.Hu Q.Hu S.C.Hu D.H.Huang T.Q.Huang W.J.Huang X.T.Huang X.y.Huang y.Huang X.L.Ji H.y.Jia K.Jia K.Jiang X.W.Jiang Z.J.Jiang M.Jin M.M.Kang I.Karpikov D.Kuleshov K.Kurinov B.B.Li C.M.Li Cheng Li Cong Li D.Li F.Li H.B.Li H.C.Li Jian Li Jie Li K.Li S.D.Li W.L.Li W.L.Li X.R.Li Xin Li y.Z.Li Zhe Li Zhuo Li E.W.Liang y.F.Liang S.J.Lin B.Liu C.Liu D.Liu D.B.Liu H.Liu H.D.Liu J.Liu J.L.Liu M.y.Liu R.y.Liu S.M.Liu W.Liu y.Liu y.N.Liu Q.Luo y.Luo H.K.Lv B.Q.Ma L.L.Ma X.H.Ma J.R.Mao Z.Min W.Mitthumsiri H.J.Mu y.C.Nan A.Neronov L.J.Ou P.Pattarakijwanich Z.y.Pei J.C.Qi M.y.Qi B.Q.Qiao J.J.Qin A.Raza D.Ruffolo A.Sáiz M.Saeed D.Semikoz L.Shao O.Shchegolev X.D.Sheng F.W.Shu H.C.Song yu.V.Stenkin V.Stepanov y.Su D.X.Sun Q.N.Sun X.N.Sun Z.B.Sun J.Takata P.H.T.Tam Q.W.Tang R.Tang Z.B.Tang W.W.Tian C.Wang C.B.Wang G.W.Wang H.G.Wang H.H.Wang J.C.Wang Kai Wang Kai Wang L.P.Wang L.y.Wang P.H.Wang R.Wang W.Wang X.G.Wang X.y.Wang y.Wang y.D.Wang y.J.Wang Z.H.Wang Z.X.Wang Zhen Wang Zheng Wang D.M.Wei J.J.Wei y.J.Wei T.Wen C.y.Wu H.R.Wu Q.W.Wu S.Wu X.F.Wu y.S.Wu S.Q.Xi J.Xia G.M.Xiang D.X.Xiao G.Xiao y.L.Xin y.Xing D.R.Xiong Z.Xiong D.L.Xu R.F.Xu R.X.Xu W.L.Xu L.Xue D.H.yan J.Z.yan T.yan C.W.yang C.y.yang F.yang F.F.yang L.L.yang M.J.yang R.Z.yang W.X.yang y.H.yao Z.G.yao L.Q.yin N.yin X.H.you Z.y.you y.H.yu Q.yuan H.yue H.D.Zeng T.X.Zeng W.Zeng M.Zha B.B.Zhang F.Zhang H.Zhang 不详 Key Laboratory of Particle Astrophysics&Experimental Physics Division&Computing Center Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China TIANFU Cosmic Ray Research Center ChengduChina Dublin Institute for Advanced Studies 31 Fitzwilliam Place2 DublinIreland Max-Planck-Institut for Nuclear Physics P.O.Box 103980Heidelberg 69029Germany School of Physical Science and Technology&School of Information Science and Technology Southwest Jiaotong UniversityChengdu 610031China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Institute for Nuclear Research of Russian Academy of Sciences Moscow 117312Russia Hebei Normal University Shijiazhuang 050024China University of Science and Technology of China Hefei 230026China State Key Laboratory of Particle Detection and Electronics China Key Laboratory of Dark Matter and Space Astronomy&Key Laboratory of Radio Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China Research Center for Astronomical Computing Zhejiang LaboratoryHangzhou 311121China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China School of Physics and Astronomy Yunnan UniversityKunming 650091China Key Laboratory of Cosmic Rays(Tibet University) Ministry of EducationLhasa 850000China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Physics and Astronomy(Zhuhai)&School of Physics(Guangzhou)&Sino-French Institute of Nuclear Engineering and Technology(Zhuhai) Sun Yat-sen UniversityZhuhai 519000&Guangzhou 510275GuangdongChina Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China APC UniversitéParis Cité

Theγ-ray emission from the W51 complex is widely acknowledged to be attributed to the interaction between the cosmic rays(CRs)accelerated by the shock of supernova remnant(SNR)W51C and the dense molecular clouds in the adjacent star-forming region,***,the maximum acceleration capability of W51C for CRs remains *** on observations conducted with the Large High Altitude Air Shower Observatory(LHAASO),we report a significant detection ofγrays emanating from the W51 complex,with energies from 2 to 200 *** LHAASO measurements,for the first time,extend theγ-ray emission from the W51 complex beyond 100 TeV and reveal a significant spectrum bending at tens of *** combining the"π^(0)-decay bump"featured data from Fermi-LAT,the broadbandγ-ray spectrum of the W51 region can be well-characterized by a simple pp-collision *** observed spectral bending feature suggests an exponential cutoff at~400 TeV or a power-law break at~200 TeV in the CR proton spectrum,most likely providing the first evidence of SNRs serving as CR accelerators approaching the PeV ***,two young star clusters within W51B could also be theoretically viable to produce the most energeticγrays observed by *** findings strongly support the presence of extreme CR accelerators within the W51 complex and provide new insights into the origin of Galactic CRs.

关键词： UHE c-ray Cosmic rays SNR W51C Star clusters

Multi-layer perceptron-based data-driven multiscale modelling of granular materials with a novel Frobenius norm-based internal variable

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2198-2218页

作者： Mengqi Wang y.T.feng Shaoheng Guan Tongming Qu Zienkiewicz Centre for Computational Engineering Faculty of Science and EngineeringSwansea UniversitySwanseaWalesSA18EPUK Institute of Theoretical and Computational Physics Graz University of TechnologyGraz8010Austria Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyClearwater BayKowloonHong KongChina

One objective of developing machine learning(ML)-based material models is to integrate them with well-established numerical methods to solve boundary value problems(BVPs).In the family of ML models,recurrent neural networks(RNNs)have been extensively applied to capture history-dependent constitutive responses of granular materials,but these multiple-step-based neural networks are neither sufficiently efficient nor aligned with the standard finite element method(FEM).Single-step-based neural networks like the multi-layer perceptron(MLP)are an alternative to bypass the above issues but have to introduce some internal variables to encode complex loading *** this work,one novel Frobenius norm-based internal variable,together with the Fourier layer and residual architectureenhanced MLP model,is crafted to replicate the history-dependent constitutive features of representative volume element(RVE)for granular *** obtained ML models are then seamlessly embedded into the FEM to solve the BVP of a biaxial compression case and a rigid strip footing *** obtained solutions are comparable to results from the FEM-DEM multiscale modelling but achieve significantly improved *** results demonstrate the applicability of the proposed internal variable in enabling MLP to capture highly nonlinear constitutive responses of granular materials.

关键词： Granular materials History-dependence Multi-layer perceptron(MLP) Discrete element method FEM-DEM Machine learning

Increasing polymer scission rate by tying an overhand knot

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Science China Chemistry 2024年第11期67卷 3498-3499页

作者： yuheng Hu Jennifer T.Ou Jim y.Huang yuanning feng Department of Chemistry and Biochemistry The University of Oklahoma

Similar to the phenomenon of knotted ropes in life, knotted climbing ropes will reduce their strength due to knots. Although computer simulations [1], theoretical speculation[2,3], and intuition [3] suggest that similar processes may occur at the nanoscale, this hypothesis has not been experimentally proven before. With the increasing maturity of molecular recognition and self-assembly, a research communication by Leigh et al. [4] published in Nature Chemistry introduced a molecular overhand knot into a polymer to study its effect on the scission rate of the polymer chain under tension.

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A particle-resolved heat-particle-fluid coupling model by DEM-IMB-LBM

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2267-2281页

作者： Ming Xia Jinlong Fu y.T.feng fengqiang Gong Jin yu Hunan Key Laboratory of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China Zienkiewicz Institute for Modelling Data and AISwansea UniversitySwanseaSA18EPUK School of Civil Engineering Southeast UniversityNanjing211189China Fujian Research Center for Tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

Multifield coupling is frequently encountered and also an active area of research in geotechnical *** this work,a particle-resolved direct numerical simulation(PR-DNS)technique is extended to simulate particle-fluid interaction problems involving heat transfer at the grain *** this extended technique,an immersed moving boundary(IMB)scheme is used to couple the discrete element method(DEM)and lattice Boltzmann method(LBM),while a recently proposed Dirichlet-type thermal boundary condition is also adapted to account for heat transfer between fluid phase and solid *** resulting DEM-IBM-LBM model is robust to simulate moving curved boundaries with constant temperature in thermal *** facilitate the understanding and implementation of this coupled model for non-isothermal problems,a complete list is given for the conversion of relevant physical variables to lattice ***,benchmark tests,including a single-particle sedimentation and a two-particle drafting-kissing-tumbling(DKT)simulation with heat transfer,are carried out to validate the accuracy of our coupled *** further investigate the role of heat transfer in particle-laden flows,two multiple-particle problems with heat transfer are *** examples demonstrate that the proposed coupling model is a promising high-resolution approach for simulating the heat-particle-fluid coupling at the grain level.

关键词： Particle-fluid interaction Heat transfer Discrete element method(DEM) Lattice Boltzmann method(LBM) Dirichlet-type thermal boundary Direct numerical simulation

FAST Observations of an Extremely Active Episode of FRB 20201124A:Ⅰ.Burst Morphology

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Research in Astronomy and Astrophysics 2022年第12期22卷 54-69页

作者： D.J.Zhou J.L.Han B.Zhang K.J.Lee W.W.Zhu D.Li W.C.Jing W.-y.Wang y.K.Zhang J.C.Jiang J.R Niu R Luo H.Xu C.F.Zhang B.J.Wang J.W.Xu P.Wang Z.L.yang y.feng National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy Peking UniversityBeijing 100871China CSIRO Space and Astronomy EppingNSW 1710Australia Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China

We report the properties of more than 600 bursts(including cluster-bursts)detected from the repeating fast radio burst(FRB)source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope during an extremely active episode on UTC 2021 September 25–28,in a series of four *** observations were carried out in the band of 1.0–1.5 GHz by using the center beam of the L-band 19-beam *** monitored the source in sixteen1 hr sessions and one 3 hr session spanning 23 *** the bursts were detected during the first four *** this first paper of the series,we perform a detailed morphological study of 624 bursts using the two-dimensional frequencytime“waterfall”plots,with a burst(or cluster-burst)defined as an emission episode during which the adjacent emission peaks have a separation shorter than 400 *** duration of a burst is therefore always longer than 1 ms,with the longest up to more than 120 *** emission spectra of the sub-bursts are typically narrow within the observing band with a characteristic width of~277 *** center frequency distribution has a dominant peak at about 1091.9 MHz and a secondary weak peak around 1327.9 *** bursts show a frequencydownwarddrifting *** on the drifting patterns,we classify the bursts into five main categories:downward drifting(263)bursts,upward drifting(3)bursts,complex(203),no drifting(35)bursts,and no evidence for drifting(121)*** are introduced based on the emission frequency range in the band(low,middle,high and wide)as well as the number of components in one burst(1,2,or multiple).We measured a varying scintillation bandwidth from about 0.5 MHz at 1.0 GHz to 1.4 MHz at 1.5 GHz with a spectral index of 3.0.

关键词： (stars:)pulsars:general Physical Data and Processes stars:individual(FRB 20201124A)

Effects of Different Immune Stress on Digestive Enzyme Activity and Expression of Small Intestinal Nutrient Transporters mRNA of Broilers

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Effects of Different Immune Stress on Digestive Enzyme Activ...

An MPI parallel DEM-IMB-LBM framework for simulating fluid-solid interaction problems

中国畜牧兽医学会动物营养学分会第十一次全国动物营养学术研讨会

作者： y.feng X.J.yang W.L.Li K.Liu y.Liu J.H.yao~* (College of Animal Science and Technology,Northwest Agriculture and Forestry University,yangling 712100,China College of Life Science,Shanxi Agricultural University,Taigu 030801,China)

An experiment with 540 one-day-old broilers(Cobb500) was conducted to investigate the effects of different immune stress on growth performance,digestive enzyme activity and expression of small intestinal nutrient transporter gene on *** chickens were divided into 5 groups with 9 replicates per group and 12 birds per replicate(group 1,control without vaccines,CK;2,simplified vaccines,SV;3,conventional vaccines, CV;4,lipopolysaccharide injected on the basis of conventional immunization,LPS;5,cyclophosphamide injected on the basis of conventional immunization,CyP).Performance parameters and small intestinal weight was measured on d 21 and d *** results showed that body weight gain(BWG) and feed intake(FI) decreased significantly when birds treated with LPS and CyP(P y on d 21(P yP injection significantly increased the small intestinal enzyme activities of broilers(P yP treatment also increased relative abundance of sodium glucose co-transporter 1,Calcium-binding protein -D28k and L-fatty acid-binding proteins mRNA of broilers(P y difference between SV and CV(P > 0.05).Results of the present study demonstrated that CK or SV treatment could reach the same growth performance, small intestine enzyme activity and relative expression of nutrient transporter mRNA as broilers with CV in the conditions of controlling rational feeding *** and CPy treatment increased small intestine enzyme activity and nutrient transporter mRNA,result of immunity stress caused energy consumption to synthesis of inflammatory factors,lower FI and BWG,finally inhibit the growth of broiler chickens.

关键词： Broilers Immunity stress Enzyme activity mRNA expression

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2219-2231页

作者： Ming Xia Liuhong Deng fengqiang Gong Tongming Qu y.T.feng Jin yu Hunan Key Laboratory of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China School of Civil Engineering Southeast UniversityNanjing211189China Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyHong KongChina Zienkiewicz Centre for Computational Engineering Swansea UniversitySwanseaSA18ENUK Fujian Research Center for Tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

The high-resolution DEM-IMB-LBM model can accurately describe pore-scale fluid-solid interactions,but its potential for use in geotechnical engineering analysis has not been fully unleashed due to its prohibitive computational *** overcome this limitation,a message passing interface(MPI)parallel DEM-IMB-LBM framework is proposed aimed at enhancing computation *** framework utilises a static domain decomposition scheme,with the entire computation domain being decomposed into multiple subdomains according to predefined processors.A detailed parallel strategy is employed for both contact detection and hydrodynamic force *** particular,a particle ID re-numbering scheme is proposed to handle particle transitions across sub-domain *** benchmarks are conducted to validate the accuracy and overall performance of the proposed ***,the framework is applied to simulate scenarios involving multi-particle sedimentation and submarine *** numerical examples effectively demonstrate the robustness and applicability of the MPI parallel DEM-IMB-LBM framework.

关键词： Discrete element method(DEM) Lattice Boltzmann method(LBM) Immersed moving boundary(IMB) Multi-cores parallelization Message passing interface(MPI) CPU Submarine landslides