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Initial pre-stress finding procedure and structural performance research for Levy cable dome based on linear adjustment theory

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第9期8卷 1366-1372页

作者： ZHANG Li-mei CHEN Wu-jun dong Shi-lin Space Structures Research Center Shanghai Jiao Tong University Shanghai 200030 China

The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented herein for the initial pre-stress finding procedure of complete cable-strut assembly. This method is based on the linear adjustment theory and does not take into account the material behavior. By using this method,the initial pre-stress of the multi self-stress modes can be found easily and the cal-culation process is simplified and efficient also. Finally,the initial pre-stress and structural performances of a particular Levy cable dome are analyzed comprehensively. The algorithm has proven to be efficient and correct,and the numerical results are valuable for practical design of Levy cable dome.

关键词： Linear adjustment theory Cable-strut structure Initial pre-stress Levy cable dome Structural performances analysis

Clay-Supported Molybdenum-Based Catalysts for Higher Alcohol Synthesis from Syngas

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Chinese Journal of Chemical Physics 2015年第5期28卷 -页

作者： Gai-mei Wu Ji-long Zhou mei-mei Lv Wei Xie Song Sun Chen Gao Wen-dong Wang Department of Chemical Physics University of Science and Technology of China Hefei 230026China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230029 China

A kind of clay-supported K-Co-Mo catalyst was prepared by a sol-gel method combined with incipient wetness impregnation. The catalyst structure was characterized by X-ray diffraction, N2 adsorption-desorption, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy techniques and its catalytic performance for higher alcohol synthesis from syngas was investigated. The active components has a high dispersion on the clay support surface. The increase of the Mo loading promoted reduction of Mo6+ but had no significant influence on the reduction of Mo4+ and Co2+ species. After reduction, a kind of lower state Moδ+ (1<δ<4) species was observed on the surface. Compared with the unsupported catalyst, the clay supported K-Co-Mo catalysts showed much higher catalytic performance for alcohol formation. The reason can be explained that the supported catalyst have a high active surface area and the mesoporous structure prolonged the residence time of intermediates for alcohol formation to some extent, which promoted the formation of higher alcohols. The high activity of the catalyst reduced at 773 K may be attributed to the high content of Moδ+ (1<δ<4) species on the surface, which was regarded as the active site for the adsorption of nondissociative CO and responsible for the alcohol formation.

关键词： Higher alcohol synthesis Clay support K-Co-Mo catalyst Syngas

New mechanism of FA in composted sludge inducing Cu fixation on Albite in open-pit mine soil

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Journal of Environmental Sciences 2022年第6期34卷 142-150页

作者： Jiapeng Wan Yifan Zeng mei Wang Bin dong Zuxin Xu State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China YANGTZE Eco-Environment Engineering Research Center China Three Gorges CorporationBeijing 100038China Shanghai Investigation Design&Research Institute Co.Ltd Shanghai 200335China

Fulvic acid(FA),typical organic matter derived from humification process in composted sludge,possesses the potential to remediate mine soils contaminated by heavy *** understand the cooper(Cu)immobilizing process in open-pit mine soil induced by FA,changes of Cu speciation in mixture of open-pit mine soil and composted sludge was tracked over 180 *** was observed that the organic-bound and residual fraction of Cu increased dramatically with the corresponding decrease of Fe/Mn oxide-bound Cu in the first 60 days,then the organic-bound fraction decreased to about its initial proportion during 60-120 days,while residual fraction still increased,and the proportion of residual Cu accounted for over85%and became stable after 120 *** reveal the mechanism of FA inducing Cu fixation on Albite which is the main phase of soil primary ore,two groups of Cu adsorption experiments with and without FA were *** the addition of FA,the adsorption capacity of Cu by Albite increased by 1.55 times and the content of residual Cu in Albite increased by7.7 *** was found that the Cu absorbed in smaller Albite particle induced by FA formed a secondary mineral——Chrysocolla,causing increase of residual fraction of *** results revealed the mechanism:FA was absorbed on the surface of Albite after complexing with Cu ions in the solution,and then it induced Cu into the interlayer and pore channels of *** Cu in the Albite was immobilized by forming Chrysocolla finally.

关键词： Fulvic acid Composted sludge Heavy metal Open-pit mine Mineralization

Local search yields a PTAS for fixed-dimensional k-means problem with penalties

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Journal of the Operations Research Society of China 2024年第2期12卷 351-362页

作者： Fan Yuan Da-Chuan Xu dong-Lei Du dong-mei Zhang Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing 100124China Faculty of Management University of New BrunswickFrederictonNB E3B 9Y2Canada School of Computer Science and Technology Shandong Jianzhu UniversityJinan 250101ShandongChina

We study a problem called the k-means problem with penalties(k-MPWP),which is a natural generalization of the typical k-means *** this problem,we have a set D of client points in R^(d),a set F of possible centers in R^(d),and a penalty cost Pj>O for each point j∈*** are also given an integer k which is the size of the center point *** want to find a center point set S■F with size k,choose a penalized subset of clients P■D,and assign every client in D\P to its open *** goal is to minimize the sum of the squared distances between every point in D\P to its assigned centre point and the sum of the penalty costs for all clients in *** using the multi-swap local search technique and under the fixed-dimensional Euclidean space setting,we present a polynomial-time approximation scheme(PTAS)for the k-MPWP.

关键词： Approximation algorithm k-means Local search Penalty

Effect of blank quenching on shear spinning forming precision of 2219 aluminum alloy complex thin-walled components

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Chinese Journal of Aeronautics 2023年第4期36卷 538-555页

作者： Zhixin LI mei ZHAN Xiaoguang FAN Yunda dong Luopeng XU School of Science Civil Aviation Flight University of ChinaGuanghan 618307China State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming

The quenching-spinning(Q-S)process,i.e.,shear spinning after blank quenching,has been increasingly utilized to form 2219 aluminum alloy complex thin-walled ***,the changes in material property,shape and stress of the blanks after quenching will affect the spin-ning forming *** this study,the rules and mechanisms of these effects are investigated based on a combined finite element(FE)model including blank quenching and component spinning *** results indicate that the increase of material strength and the existence of distortion of the quenched blank lead to a notable increase in the non-uniformity of the circumferential compres-sive stress in the spinning area and the increase of the flange swing height during *** changes result in an increase in the wall thickness and component-mandrel gap of the *** quenching residual stress has little effect on wall thickness and roundness but can noticeably reduce the component-mandrel *** is because that the existence of quenching residual stress of the blank can lead to the decrease of the maximum circumferential compressive stress of the workpiece in spinning and an obvious drop in the maximum compressive stress after reaching the stress *** distortion is the main factor affecting the ***,the opti-mized installation way of the blank for spinning is obtained.

关键词： 2219 aluminum alloy Complex thin-walled com-ponents Finite element analysis Quenching distortion Residual stress Shear spinning

Synthesis and Crystal Structure of an Indenylnickel(II) NHC Complex (Ind)NiBr(1,3-bisbenzylimidazol-2-ylidene)

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Chinese Journal of Structural Chemistry 2006年第10期25卷 1255-1259页

作者： HU dong-mei SUN Hong-mei WANG Yong-Sheng SHEN Qi XUE Feng The Key Lab of Organic Synthesis of Jiangsu Province College of Chemistry and Chemical Engineering Suzhou University Suzhou 215123 China Department of Chemistry The National University of Singapore Singapore 117543 Republic of Sinapore

The complex （Ind）NiBr（1,3-bisbenzylimidazol-2-ylidene）（Ind = indenyl） 1 has been prepared in ca. 65% yield via the reaction of （Ind）2Ni with an equivalent of 1,3-bis-benzylimidazolium bromide in THF/CH2Cl2 at 45℃, supported by elemental analysis, NMR spectroscopy and X-ray crystal determination. The crystal belongs to the triclinic system, space group Pi with a = 7.072（1）, b = 11.264（2）, c = 14.541（3）°A, α = 102.21（3）,β = 93.44（3）,γ = 90.81（3）°, V = 1129.7（4）°A^3, Z = 2, Mr = 502.08, Dc = 1.476 g/cm^3, F（000） = 512, μ= 2.642 mm^-1, R = 0.0490 and wR = 0.1137 for 3913 observed reflections （I〉 2σ（I））. The center nickel atom is coordinated by a bromide ligand, a carbene carbon and three carbon atoms of the five-membered indenyl group to form either a highly distorted square pyramid or a highly distorted square plane.

关键词： nickel complex indenyl ligand N-heterocyclic carbene

Observational evidence of magnetic reconnection in a coronal bright point

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Research in Astronomy and Astrophysics 2020年第9期20卷 171-182页

作者： zong-Jun Ning dong Li Qing-Min Zhang Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryNanjing 210033China

Magnetic reconnection is considered to be the fundamental process by which magnetic energy is converted into plasma or particle kinetic *** reconnection is a widely applied physics model to explain the solar eruption events,such as coronal bright points(CBPs).Meanwhile,it is an usual way of the solar physics research to look for the observational evidences of magnetic reconnection in the solar eruption events in order to support the *** this paper,we have explored the evidences of magnetic reconnection in a CBP observed by the Atmospheric Imaging Assembly(AIA)onboard the Solar Dynamics Observatory(SDO)at NOAA No.11163 on 2011 March *** observations show that this event is a small-scale loop system in active regions that have similar size as a traditional CBP and it might shed light on the physics of a traditional *** CBP is bright in all nine AIA wavelengths and displays a flaring development with three bursts *** burst exhibits a pair of bi-directional jets almost along a *** originate from the same position(CBP core),then move in the opposite *** findings are well consistent with the magnetic reconnection process by which the bi-directional plasma outflows are produced and radiate the bi-directional jets detected by SDO/*** facts further support the conclusion that the CBP is produced by the magnetic reconnection process.

关键词： Sun:UV radiation Sun:corona Sun:oscillation

Effects of flow parameters on thermal performance of an inner-liner anti-icing system with jets impingement heat transfer

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Chinese Journal of Aeronautics 2021年第9期34卷 119-132页

作者： Zhiqiang GUO mei ZHENG Qian YANG Xiaofeng GUO Wei dong School of Mechanical Engineering Shanghai Jiaotong UniversityShanghai 200240China

The multiple jets impingement heat transfer is widely applied in the wing anti-icing *** is challenging to apply the similarity criterion to carry out the anti-icing experiments due to the complex flow and heat transfer *** the present study,the full-scale slat model is used to carry out anti-icing experimental researches in a 2 m×3 m icing wind tunnel of China Aerodynamics Research and Development *** effects of icing parameters Liquid Water Content(LWC)and Median Volume Diameter(MVD)and hot air parameters(mass flow rate and temperature)on the thermal performance of an inner-liner anti-icing system with jets impingement heat transfer are *** effects of the experimental parameters are analyzed in detail by combining impingement and evaporation heat transfer *** impingement hot air mass flow rate dramatically affects the heat transfer performance of the impingement stagnation region within the range of the experimental *** temperature of impingement hot air and that of wing skin are approximately linear *** experimental results show the effects of LWC and MVD on water film formation and runback ice *** formation of water film is analyzed by an analytical method based on the wing skin temperature difference of dry and wet air conditions.

关键词： Hot air anti-icing system Icing Icing wind tunnel Jets impingement heat transfer Thermal performance

Numerical analysis of vehicle-bridge coupling vibration concerning nonlinear stress-dependent damping

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Frontiers of Structural and Civil Engineering 2022年第2期16卷 239-249页

作者： Pengfei LI Jinquan ZHANG Shengqi mei Zhenhua dong Yan MAO Bridge and Tunnel Technology Research Center Research Institute of HighwayMinistry of TransportBeijing100088China National Engineering Laboratory of Bridge Structure Safety Technology Research Institute of HighwayMinistry of TransportBeijing100088China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China School of Civil Engineering Shijiazhuang Tiedao UniversityShijiazhuang050043China

Damping is known to have a considerable influence on the dynamic behavior of *** fixed damping ratios recommended in design codes do not necessarily represent the complicated damping characteristics of bridge *** study investigated the application of stress-dependent damping associated with vehicle-bridge coupling vibration and based on that investigation proposed the stress-dependent damping *** results of the investigation show that the stress-dependent damping ratio is significantly different from the constant damping ratio(5%)defined in the standard *** vehicles travel at speeds of 30,60,and 90,the damping ratios of the bridge model are 3.656%,3.658%,and 3.671%,*** peak accelerations using the regular damping ratio are 18.9%,21.3%,and 14.5%of the stress-dependent damping ratio,*** the vehicle load on the bridge is doubled,the peak acceleration of the mid-span node increases by 5.4 times,and the stress-related damping ratio increases by 2.1%.A corrugated steel-web bridge is being used as a case study,and the vibration response of the bridge is compared with the measured *** acceleration response of the bridge which was calculated using the stress-dependent damping ratio is significantly closer to the measured acceleration response than that using the regular damping ratio.

关键词： vehicle-bridge vibration system dynamic analysis stress-dependent damping energy dissipation