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Evaluating the accuracy performance of Lucas-Kanade algorithm in the circumstance of PIV application

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Science China(Physics,Mechanics & Astronomy) 2015年第10期58卷 60-75页

作者： PAN chong xuE Dong xu Yang WANG JinJun WEI RunJie Fluid Mechanics Key Laboratory of Ministry of Education Institute of Fluid Mechanics Beihang University Beijing Micro Vec Incorporated Company

Lucas-Kanade(LK) algorithm, usually used in optical flow filed, has recently received increasing attention from PIV community due to its advanced calculation efficiency by GPU acceleration. Although applications of this algorithm are continuously emerging,a systematic performance evaluation is still lacking. This forms the primary aim of the present work. Three warping schemes in the family of LK algorithm: forward/inverse/symmetric warping, are evaluated in a prototype flow of a hierarchy of multiple two-dimensional vortices. Second-order Newton descent is also considered here. The accuracy & efficiency of all these LK variants are investigated under a large domain of various influential parameters. It is found that the constant displacement constraint, which is a necessary building block for GPU acceleration, is the most critical issue in affecting LK algorithm's accuracy, which can be somehow ameliorated by using second-order Newton descent. Moreover, symmetric warping outbids the other two warping schemes in accuracy level, robustness to noise, convergence speed and tolerance to displacement gradient, and might be the first choice when applying LK algorithm to PIV measurement.

关键词： PIV Lucas-Kanade (LK) algorithm accuracy performance FFT-PIV algorithm

A Calculation of Electron Impact for the 3d5/2→2p3/2 Line Emission of Fe^(23+)

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Chinese Physics Letters 2000年第6期17卷 403-404页

作者： CHEN chong-Yang QI Jing-Bo WANG Yan-Sen xu xue-Ji SUN yong-Sheng Institute of Modern Physics Fudan UniversityShanghai 200433 Institute of Electric Light Sources Fudan UniversityShanghai 200433 Institute of Applied Physics and Computational Mathematics Beijing 100088

By using the semi-relativistic distorted-wave Born exchange method,electron impact cross sections for the Fe^(23+)line emission 3_(d5/2)→2_(p3/2)are *** calculation involves line formation by direct electron-impact excitation,radiative cascade,resonant excitation,and dielectronic recombination satellites with captured electron in the n≥5 *** results show a good agreement with the recent measurements.

关键词： excitation Electron resonant

Preliminary Assessment of Simulations of Climate Changes over China by CMIP5 Multi-Models

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Atmospheric and Oceanic Science Letters 2012年第6期5卷 489-494页

作者： xu Ying xu chong-Hai National Climate Center China Meteorological AdministrationBeijing 100081China Meteorological Observation Centre China Meteorological AdministrationBeijing 100081China Laboratory for Climate Studies China Meteorological AdministrationBeijing 100081China

Based on 18 global climate models' simulations of the 20th century climate, a set of experiments within phase five of the Coupled Model Inter-comparison Project (CMIP5), the performances of simulating the present climate over China are assessed. Compared with observations, models can capture the dominant features of the geographic distributions of temperature and precipitation during 1961-2005. For the temporal changes of temperature, models appear to have a good performance on reproducing the warming tendency but show limited skills for precipitation. For the regional mean temperature and precipitation over the whole of China, most models underestimate the actual temperature and overestimate precipitation. Concerning the standard deviations of simulations by the 18 models, they are larger for temperature in the western part of China, while the standard deviations are larger for precipitation in the South.

关键词： assessment simulation CMIP5 China

Squeeze flow of interstitial Herschel-Bulkley fluid between two rigid spheres

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Particuology 2010年第4期8卷 360-364页

作者： Chunhui xu Li Yuan yong xu Wenbin Hang College of Science China Agricultural University Beijing 100083 China

Interaction between two spheres with an interstitial fluid is crucial in discrete element modeling for simulating the behaviors of ＇wet＇ particulate materials. The normal viscous force of squeeze flow between two arbitrary rigid spheres with an interstitial HerscheI-Bulkley fluid was studied on the basis of Reynolds＇ lubrication theory, resulting in analytical integral expressions of pressure distribution and the viscous force between the two spheres. According to the variation of shear stress, the fluid was divided into yielding and unyielding regions, followed by a discussion on the thickness of the two regions. The result of this paper could be reduced to either the power-law fluid or the Bingham fluid case.

关键词： Wet granuleDiscrete element method Herschel-Bulldey fluid Viscous force

A comparative study on Sn macrosegregation behavior of ternary Al-Sn-Cu alloys prepared by gravity casting and squeeze casting

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China Foundry 2023年第1期20卷 63-70页

作者： Ming xu Yan-guo Yin Cong-min Li Cong-chong Duan College of Mechanical Engineering Hefei University of TechnologyHefei 230002China Anhui Yihui New Materials Co. Ltd.Hefei 230000China

A comprehensive study on Sn macrosegregation behavior in ternary Al-Sn-Cu alloys was carried out by comparative analysis between gravity casting and squeeze casting *** microstructure and Sn distribution of the castings were characterized by metallography,scanning electron microscopy(SEM),energy-dispersive X-ray(EDX)spectroscopy,and a direct reading *** show that there are obvious differences in Sn morphology between gravity casting and squeeze casting *** squeeze casting condition,the grain size of the casting is smaller and the distribution ofβ(Sn)is *** effectively reduces the segregation of triangular grain boundary as well as the segregation of *** segregation types of Sn in gravity casting and squeeze casting samples are obviously *** upper surfaces of gravity casting samples show severe negative segregation,while all the lower surfaces have positive *** with gravity casting,squeeze casting solidifies under isostatic *** to the direct contact between the upper surface of the casting and the mold,the casting solidifies faster under higher undercooling degree and ***,the uniform distribution of Sn reduces the segregation phenomenon on the surface of the casting.

关键词： ternary Al-Sn-Cu alloy squeeze casting macrosegregation mechanism

Pricing the spare bandwidth: towards maximizing data center's profit

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Science China(Information Sciences) 2016年第10期59卷 50-59页

作者： yong ZHAN Du xu Hongfang YU School of Communication & Information Engineering University of Electronic Science and Technology of China

To provide tenants with predictable network performance, tenants are allowed to purchase specified amount of data center network(DCN) resources(e.g., bandwidth). Then, data center will reserve the purchased resources for the corresponding tenants. Meanwhile, some DCNs are work conserving, which means that the spare bandwidth will be fairly shared by all active tenants. Even though the amount of the spare bandwidth is stochastic and uncertain, DCN providers are not likely to give away it for free. Thus, data center with work conserving may impose extra payment on tenants for using the spare bandwidth. In this paper, we propose a suitable tariff to charge for the usages of DCN resources, which includes a bill for the usage of the spare bandwidth. Through theoretical analysis and simulation, we demonstrate that our tariff can incentivize tenants to adjust their purchases of bandwidths, which can lead to the improvement of data center's profit by 27.4%without impairing the social welfare.

关键词： spare bandwidth data center network(DCN) bandwidth reservation work conserving pricing/tariff

A low redox potential and long life organic anode material for sodium-ion batteries

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Journal of Energy Chemistry 2025年第1期100卷 557-564页

作者： Zhi Li Yang Wei Kang Zhou Xin Huang Xing Zhou Jie xu Taoyi Kong Junwei Lucas Bao Xiaoli Dong yonggang Wang Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Institute of New Energy Collaborative Innovation Center of Chemistry for Energy Materials (iChEM) Fudan University Department of Chemistry Boston College School of Materials Science and Engineering Anhui University of Technology

Sodium-ion batteries （SIBs） with organic electrodes are an emerging research direction due to the sustainability of organic materials based on elements like C,H,O,and sodium ***,organic electrode materials for SIBs are mainly used as cathodes because of their relatively high redox potentials（>1 V）.Organic electrodes with low redox potential that can be used as anode are ***,a novel organic anode material （tetrasodium 1,4,5,8-naphthalenetetracarboxylate,Na4TDC） has been developed with low redox potential （<0.7 V） and excellent cyclic *** three-sodium storage mechanism was demonstrated with various in-situ/ex-situ spectroscopy and theoretical calculations,showing a high capacity of 208 mAh/g and an average decay rate of merely 0.022%per ***,the Na4TDC-hard carbon composite can further acquire improved capacity and cycling stability for 1200 cycles even with a high mass loading of up to 20 mg *** pairing with a thick Na3V2（PO4）3cathode (20.6 mg cm-2),the as-fabricated full cell exhibited high operating voltage （2.8 V）,excellent rate performance and cycling stability with a high capacity retention of 88.7% after 200 cycles,well highlighting the Na4TDC anode material for SIBs.

关键词： Organic anode material Low redox potential Composite anode Sodium-ion batteries

The Projection of Temperature and Precipitation over China under RCP Scenarios using a CMIP5 Multi-Model Ensemble

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Atmospheric and Oceanic Science Letters 2012年第6期5卷 527-533页

作者： xu chong-Hai xu Ying Meteorological Observation Centre China Meteorological AdministrationBeijing 100081China National Climate Center China Meteorological AdministrationBeijing 100081China Laboratory for Climate Studies China Meteorological AdministrationBeijing 100081China

Climate changes in 21st century China are described based on the projections of 11 climate models under Representative Concentration Pathway (RCP) scenarios. The results show that warming is expected in all regions of China under the RCP scenarios, with the northern regions showing greater warming than the southern regions. The warming tendency from 2011 to 2100 is 0.06°C/10 a for RCP2.6, 0.24°C/10 a for RCP4.5, and 0.63°C/10 a for RCP8.5. The projected time series of annual temperature have similar variation tendencies as the new greenhouse gas (GHG) emission scenario pathways, and the warming under the lower emission scenarios is less than under the higher emission scenarios. The regional averaged precipitation will increase, and the increasing precipitation in the northern regions is significant and greater than in the southern regions in China. It is noted that precipitation will tend to decrease in the southern parts of China during the period of 2011-2040, especially under RCP8.5. Compared with the changes over the globe and some previous projections, the increased warming and precipitation over China is more remarkable under the higher emission scenarios. The uncertainties in the projection are unavoidable, and further analyses are necessary to develop a better understanding of the future changes over the region.

关键词： projection RCP scenarios China

Inhibition of the cGAS–STING pathway:contributing to the treatment of cerebral ischemia-reperfusion injury

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Neural Regeneration Research 2025年第7期20卷 1900-1918页

作者： Hang Yang Yulei Xia Yue Ma Mingtong Gao Shuai Hou Shanshan xu Yanqiang Wang School of Clinical Medicine Shandong Second Medical UniversityWeifangShandong ProvinceChina Department of Emergency The Affiliated Hospital of Weifang Medical UniversityWeifangShandong ProvinceChina Department of Neurology Ⅱ The Affiliated Hospital of Weifang Medical UniversityWeifangShandong ProvinceChina

The cGAS–STING pathway plays an important role in ischemia-reperfusion injury in the heart,liver,brain,and kidney,but its role and mechanisms in cerebral ischemia-reperfusion injury have not been systematically ***,we outline the components of the cGAS–STING pathway and then analyze its role in autophagy,ferroptosis,cellular pyroptosis,disequilibrium of calcium homeostasis,inflammatory responses,disruption of the blood–brain barrier,microglia transformation,and complement system activation following cerebral ischemia-reperfusion *** further analyze the value of cGAS–STING pathway inhibitors in the treatment of cerebral ischemia-reperfusion injury and conclude that the pathway can regulate cerebral ischemia-reperfusion injury through multiple *** of the cGAS–STING pathway may be helpful in the treatment of cerebral ischemia-reperfusion injury.

关键词： calcium homeostasis cellular autophagy cerebral ischemia-reperfusion injury cGAS–STING pathway ferroptosis gut–brain–microbiota axis inflammatory light chain 3 microglial cells Syntaxin-17 protein