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Interactive Effects of Wind Tunnel Sidewalls on Flow structures around 2D Airfoil Model

Journal of Thermal Science 2023年第2期32卷 708-717页

作者： BAI Jingyan ZHANG Lei YANG Ke ZHAO Daiqing XU Jianzhong Guangzhou institute of Energy Conversion Chinese Academy of SciencesGuangzhou 510650China institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Key laboratory of CAS for Wind Utility Chinese Academy of SciencesBeijing 100190China

This paper presents the effect of wind tunnel sidewalls on the wind turbine airfoils with experimental and numerical *** test is carried out in a low-speed wind tunnel at Re=2.62×10^(5).Pressures acting on the airfoil surface are measured by a multiport pressure ***,the oil flow visualization technique is used to investigate the flow field characteristics of the airfoil ***,a numerical simulation was conducted with the measurement *** a result,it is clarified the flow structures on the airfoil surface depend strongly on the angles of attack and the *** small angles of attack,the three-dimensional separation caused by the interaction between the sidewall boundary layer and the airfoil boundary layer is very small,and only appears near the junction of the airfoil model and the *** corner separation becomes large with the increase of the angle of *** the middle part of the testing model,the boundary layer flow evolves into three-dimensional separation,i.e.,stall cell,when the separation develops to an appreciate *** stall phenomenon will further spread from the center line to sidewalls with the increase of the angle of attack;and then,its development will be limited by the sidewall boundary layer ***,the simulation shows that the sidewall make the pressure coefficient Cpdecrease,and proper boundary condition can maintain two-dimensional flow at large angles of attack by eliminating the influence of corner vortices.

关键词： airfoil experiment sidewall corner vortex stall cell airfoil-wall junction

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Distribution of Vascular Plant Species Richness Along an Elevational Gradient in the Dongling Mountains, Beijing, China

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Journal of Integrative Plant Biology 2006年第2期48卷 153-160页

作者： Hai-Bao Ren Shu-Kui Niu Lin-Yan Zhang Ke-Ping Ma Laboratory of Quantitative Vegetation Ecology Institute of Botany the Chinese Academy of Sciences Beijing 100093 China College of Natural Resources and Environment Beijing Forestry University Beijing 100083 China International institute of Earth System Science Nanjing University Nanjing 210093 China

Quantifying spatial patterns of species richness and determining the processes that give rise to these patterns are core problems In blodlverslty theory. The aim of the present paper was to more accurately detect patterns of vascular species richness at different scales along altitudinal gradients In order to further our understanding of blodlverslty patterns and to facilitate studies on relationships between blodlverslty and environmental factors. Species richness patterns of total vascular plants species, Including trees, shrubs, and herbs, were measured along an altitudinal gradient on one transect on a shady slope In the Dongllng Mountains, near Beljlng, China. Direct gradient analysis, regression analysis, and geostatlstlcs were applied to describe the spatial patterns of species richness. We found that total vascular species richness did not exhibit a linear pattern of change with altitude, although species groups with different ecological features showed strong elevatlonal patterns different from total species richness. In addition to total vascular plants, analysis of trees, shrubs, and herbs demonstrated remarkable hierarchical structures of species richness with altitude （I.e. patchy structures at small scales and gradients at large scales）. Species richness for trees and shrubs had similar spatial character-Istics at different scales, but differed from herbs. These results Indicated that species groups with similar ecological features exhibit similar blodlverslty patterns with altitude, and studies of blodlverslty based on species groups with similar ecological properties or life forms would advance our understanding of variations In species diversity. Furthermore, the gradients or trends appeared to be due mainly to local variations In species richness means with altitude. We also found that the range of spatial scale dependencies of species rlchnese for total vascular plants, trees, shrubs, and herbs was relatively large. Thus, to detect the relationshi

关键词： geostatistics life form patterns scale species richness.

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Syntheses,Crystal structures and Properties of Two New Zn Based Boron Imidazolate Frameworks

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Chinese Journal of Structural Chemistry 2021年第7期40卷 865-870,838页

作者： BI Ming-Yue WEN Yi-Hang ZHANG Hai-Xia ZHANG Jian Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces Institute of Physical ChemistryZhejiang Normal UniversityJinhua 321004China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Two new boron imidazolate frameworks(BIFs),Zn2[HBH(2-mim)3]2(1,2-PEA)2(EG)2(BIF-120,EG=ethylene glycol)and Zn[BH(2-mim)3](1,2-HPEA)(BIF-121),were successfully synthesized by mixing the KBH(2-mim)3 ligand and the semirigid aromatic dicarboxylate ligand 1,2-benzenediacetic acid(1,2-H2PEA)under solvothermal *** this paper,the two samples were structurally characterized by single-crystal X-ray diffraction and tested by infrared spectroscopy(IR),UV-visible spectroscopy(UV-Vis),thermogravimetric analysis TGA and X-ray powder *** addition,the solid-state luminescent properties of these crystals were also investigated.

关键词： boron imidazolate frameworks crystal structure X-ray crystallography luminescent

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Structural, magnetic properties, and electronic structure of hexagonal FeCoSn compound

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Chinese Physics B 2018年第2期27卷 476-481页

作者：李勇代学芳刘国栋魏志阳刘恩克韩小磊杜志伟郗学奎王文洪吴光恒 School of Material Science and Engineering Hebei University of Technology State Key Laboratory for Magnetism Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences National Analysis and Testing Center for Nonferrous Metals & Electronic Materials Beijing General Research Institute for Non-ferrous Metals

The structural, magnetic properties, and electronic structures of hexagonal Fe Co Sn compounds with as-annealed bulk and ribbon states were investigated by x-ray powder diffraction（XRD）, differential scanning calorimetry（DSC）, transmission electron microscope（TEM）, scanning electron microscope（SEM）, magnetic measurements, and first-principles calculations. Results indicate that both states of FeCoSn show an Ni_2In-type hexagonal structure with a small amount of FeCo-rich secondary phase. The Curie temperatures are located at 257 K and 229 K, respectively. The corresponding magnetizations are 2.57 μB/f.u. and 2.94 μB/f.u. at 5 K with a field of 50 kOe（1 Oe = 79.5775 A·m^（-1））. The orbital hybridizations between 3 d elements are analyzed from the distribution of density of states（DOS）, showing that Fe atoms carry the main magnetic moments and determine the electronic structure around Fermi level. A peak of DOS at Fermi level accounts for the presence of the FeCo-rich secondary phase. The Ni_2In-type hexagonal FeCoSn compound can be used during the isostructural alloying for tuning phase transitions.

关键词： FeCoSn hexagonal structure first-principles calculations

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Catalytic combustion of soot particulates over La_(2-x)K_xNiMnO_6 catalysts

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Journal of Natural Gas Chemistry 2011年第4期20卷 384-388页

作者： Wenjuan Shan Jiali Yang Lihua Yang Na Ma institute of Chemistry for Functionalized Materials College of Chemistry and Chemical Engineering Liaoning Normal University Dalian 116029 Liaoning China

Nanosized La2-xKxNiMnO6 catalysts with ABO3 type perovskite-like structure were prepared by auto-combustion method using citric acid as a ligand to control particle size and *** structures and properties of these perovskite-like oxides were investigated by X-ray powder diffraction（XRD）and temperature-programmed reduction（TPR）.The catalytic activities for soot combustion were evaluated by temperature- programmed oxidation（TPO）with pure O2 and O2/NOx as oxidant,*** the La2-xKxNiMnO6 catalysts,the partial substitution of K at A-site leads to an increase of the concentrations of high valence cation and oxygen vacancy,which enhance the catalytic activity for soot *** optimal substitution amount of K was equal to x=0.4 among these ***（peak temperature）in O2-TPO profile was 420-C and Tp in O2/NOx-TPO profile was 370-C over La1.6K0.4NiMnO6 catalyst for soot particulates combustion under loose contact conditions between catalyst and soot.

关键词： soot oxidation La2-xKxNiMnO6 perovskite-like active oxygen

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Spatiotemporal Patterns and Dynamics of Species Richness and Abundance of Woody Plant Functional Groups in a Tropical Forest Landscape of Hainan Island,South China

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Journal of Integrative Plant Biology 2008年第5期50卷 547-558页

作者： Zhi-Dong Zhang Run-Guo Zang Yao-Dong Qi Key Laboratory of Forest Ecology and Environment the State Forestry Administration institute of Forest Ecology Environment and Protection Chinese Academy of Forestry Beijing 100091 China Yantai institute of Coastal Zone Research for Sustainable Development the Chinese Academy of Sciences Yantai 264003 China

Tropical forests are among the most species-diverse ecosystems on Earth. Their structures and ecological functions are complex to understand. Functional group is defined as a group of species that play similar roles in an ecosystem. The functional group approach has been regarded as an effective way of linking the compositions of complex ecosystems with their ecological functions. To understand the variation of functional groups in species-rich ecosystems after disturbance, the present study investigated the spatial pattern and temporal dynamics of woody plants in a typically fragmented natural forest landscape of Hainan Island in South China. The study area was classified into eight landscape types based on vegetation type, disturbance manner and the time of recovery. The woody plant species were aggregated into seven functional groups based on the growth form, successional status and plant size. The results gained from the present study showed that all functional groups, except for the emergent and canopy tree species, were present in all eight landscape types. Each landscape type had different numbers of dominant functional groups. There are similar species richness and stem abundance structure among functional groups between mid-successional clear cut lowland rainforest and old growth tropical coniferous forest. This similarity exists in selective logged lowland rainforest and old-growth lowland rainforest, as well as among landscape types of montane rainforest. The functional groups with the same successional status had similar patterns of species richness and stem abundance ratios among different landscape types. The variation patterns of functional groups along the successional stages in terms of species richness and stem abundance among the tropical lowland rainforest landscape types were more similar to each other than those in the tropical montane rainforest landscape types. This study provides further support for the competition-colonization tradeoff and

关键词： forest landscape types functional groups Hainan Island recovery dynamics spatial variation species diversity stem abundance tropical forests,

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Manifold learning of four-dimensional scanning transmission electron microscopy

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npj Computational Materials 2019年第1期5卷 1097-1104页

作者： Xin Li Ondrej E.Dyck Mark P.Oxley Andrew R.Lupini Leland McInnes John Healy Stephen Jesse Sergei V.Kalinin Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA institute for Functional Imaging of Materials Oak Ridge National LaboratoryOak RidgeTN 37831USA Tutte institute for Mathematics and Computing OttawaCanada

Four-dimensional scanning transmission electron microscopy(4D-STEM)of local atomic diffraction patterns is emerging as a powerful technique for probing intricate details of atomic structure and atomic electric ***,efficient processing and interpretation of large volumes of data remain challenging,especially for two-dimensional or light materials because the diffraction signal recorded on the pixelated arrays is *** we employ data-driven manifold leaning approaches for straightforward visualization and exploration analysis of 4D-STEM datasets,distilling real-space neighboring effects on atomically resolved deflection patterns from single-layer graphene,with single dopant atoms,as recorded on a pixelated *** extracted patterns relate to both individual atom sites and sublattice structures,effectively discriminating single dopant anomalies via multimode *** believe manifold learning analysis will accelerate physics discoveries coupled between data-rich imaging mechanisms and materials such as ferroelectric,topological spin,and van der Waals heterostructures.

关键词： manifold straight details

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Structural Traces of Secondary Faults(Fractures) along the Main Faults and Their Reliability as Kinematic Indicators

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Acta Geologica Sinica(English Edition) 2011年第5期85卷 1137-1149页

作者： Jin ZHANG Jinyi LI Zongjin MA Wenjun REN institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China institute of Geology China Earthquake Administration Beijing 100029 China Department of Chang Qing Geophysical Survey Geophysical Company Limited China National Petroleum Corporation Xi'an 710000 China

Secondary/minor structures occurring along the main fault surfaces are important indicators for judging the kinematic characteristics of ***,many factors can lead to the formation of these structures,which results in the difficulty for rapid judgment and application in the fields.A series of secondary faults/fractures developed due to the movement of main faults are the most important and widespread phenomena in the scope of brittle *** morphology of the main fault surfaces is various,and former researchers mainly discussed the structures on the main even fault surfaces. However,the fluctuation of fault surfaces is the intrinsic character of the faults,and the intersection between the main fault and secondary faults/fractures can produce a series of kinematic indicators on the main fault *** on previous studies and our observations,*** structural traces of the P,R,R',T and X shears/faults along the main faults,some indicators which are rarely reported previously,are described in the ***,their reliabilities are also discussed,and more practical and reliable criteria are brought *** suggest that the simple application of congruous and incongruous steps without knowing their exact origins should be abandoned in the fields,and several types of indicators along one fault surface should be checked with each other as much as ***,the origins of some other arcuate indicators on the fault surfaces are also discussed,and new models are brought forward.

关键词： secondary fracture/fault kinematic indicator fault surface fluctuation

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Unsteady flow structure of an airfoil in ground effect

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Journal of Shanghai University(English Edition) 2010年第3期14卷 228-234页

作者：钱建林代钦 Shanghai institute of Applied Mathematics and Mechanics Shanghai University

Particle image velocimetry （PIV） experimental results of wake flow structure of a NACA0012 airfoil with small attack angle mounted above water surface are *** experiment was carried out in a small-scale wind-wave *** diameter of wind-wave tunnel test section is 1.7 m （long） × 0.4 m （width） × 0.4 m （height）.The flow fields around the airfoil were measured under four diffierent conditions by varying the distance between the airfoil and the water *** attack angle of the airfoil was kept 10- during the *** each experimental condition,the time series of particle images was captured to calculate continuous evolution of the velocity *** velocity fields were ensemble averaged to get the statistic parameters such as mean velocity and *** instantaneous velocity fields for each case are introduced to show the basic flow structure of wind surface flow *** aerodynamic loads acting on the airfoil are analyzed qualitatively according to the mean vorticity distribution in the flow field based on the theory of vorticity *** results indicate that the flow structures and drag/lift force of the airfoil alter remarkably with the changing distance between the airfoil and water surface.

关键词： NACA0012 airfoil water surface mean vorticity field particle image velocimetry (PIV) measurement ground effect

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A polypropylene melt-blown strategy for the facile and efficient membrane separation of oil-water mixtures

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Chinese Journal of Chemical Engineering 2021年第1期34卷 383-390页

作者： Zhenqiang Zhang Danfeng Yu Xiubin Xu Huayi Li Taoyan Mao Cheng Zheng Jianjia Huang Hui Yang Zihan Niu Xu Wu School of Chemistry and Chemical Engineering Guangzhou UniversityGuangzhou 510006China CAS Key Lab of Engineering Plastics Institute of ChemistryChinese Academy of SciencesBeijing 100190China CAS Key Lab of Colloid Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

Porous materials with selective wettability and permeability have significant importance in oil-water separation,but complex fabrication processes are typically required to obtain the desired structures with suitable surface *** this work,an industrial melt-blown strategy that utilized commercially available polypropylene(PP)was used for the large-scale fabrication of superhydrophobic/superoleophilic membranes with staggered fabric *** membranes could readily separate different oils including pump oil and crude oil from various aqueous solutions such as strongly acidic,alkaline,and saline *** addition,the separation efficiencies of these membranes exceeded 99%,and they could remain functional even after exposure to corrosive *** anticipate that this work will further the design of membranes and enhance their applicability in oil-water separation,and provide researchers and engineers with a more effective tool for performing challenging separations and mitigating pollution.

关键词： Separation Polypropylene membranes Surface Superhydrophobicity Superoleophilicity Environment

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