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Metal bioaccumulation in plant leaves from an industrious area and the Botanical Garden in Beijing

Journal of Environmental Sciences 2005年第2期17卷 294-300页

作者： LIUYan-ju DINGHui ZHUYong-guan BeijingCentreforPhysicalandChemicalAnalysis Beijing100089China／／ResearchCenterforEco-EnvironmentalSciencesChineseAcademyofSciencesBeijing100085China BeijingCentreforPhysicalandChemicalAnalysis Beijing100089China ResearchCenterforEco-EnvironmentalSciences ChineseAcademyofSciencesBeijing100085China

The concentrations of Fe, Mn, Al, Zn, Pb, Ni, Cr, and As were measured in soils and leaves from 21 plant species growing on hills near the Beijing Steel Factory(BSF) and 17 plant species in the Beijing Botanical Garden(BBG). The results showed that soils from BSF were Zn contaminated according to the threshold of natural background of China. There was a metal contamination of the soils by Ni, and Cr in BSF comparing with those in BBG. The comparison between concentrations of metals in leaves from both sites indicated that, in general, accumulation of metals in the leaves of the same species was significantly different between the two sites. Even within the same locality each species accumulation of metals was significantly variable. The study aimed to screen landscape plants for the capacity to clean-up toxic metals in soils, and developed an overall metal accumulation index(MAI) for leaves and then categorized the MAI that can be applied broadly in the selection of species in polluted areas. To do this, the spectrum of MAI values were divided into four classes: strongly accumulated(SA or grade I), moderately accumulated(MA or grade II), intermediately accumulated(IA or grade III), and weakly accumulated(WA or grade IV). The results showed that elemental association between Fe, Al, Ni, and As was generally highly correlated with each other in the sampling sites. This may suggest their common biochemical characteristics. Generally, those species containing strong and moderate accumulation in both sites are considered including Vitex negundo, Broussonetia papyrifera, Ulmus pumila, and Rubia cordifolia. At BSF and other industrial sites with a similar ecosystem, strong and moderate accumulation species include Sophora japonica, Ampelopsis aconitifolia var. glabra, Platycladus orientalis, Wikstroemia chamaedaphne, Cleistogenes squarrosa, Grewia biloba, and in BBG, in addition Setaria viridis, Cotinus coggygria, Lespedeza floribunda, Rhamnus parvifolia, Lespedeza tomento

关键词： Fe Mn Al Zn Pb Ni As metal accumulation index(MAI)

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Non-isothermal Kinetic Analysis on the Thermal Decomposition of the Phase 517 from Hydration Product of Magnesium Sulfide Cement

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Journal of Wuhan University of Technology(Materials Science) 2023年第2期38卷 374-380页

作者： CUI Baodong guan Yan BI Wanli School of Materials and Metallurgy University of Science and TechnologyLiaoningAnshan110325China School of Materials Science and Engineering Shenyang Ligong UniversityShenyang110159China

In order to better understand the thermodynamic properties of magnesium oxysulfate(MOS)cement,pure reagent was analyzed to prepare magnesium sulfide cement,non-isothermal kinetics calculation of the main hydration products was also carried out,and the conversion process of magnesium sulfide cement 517 phase at different temperatures was *** of magnesium sulfide cement prepared was measured by XRD technique,and decomposed by a comprehensive thermal analyzer,and DSC curves of magnesium sulfide cement under different temperature rising rates were processed by Kinssinger method and Dolye-Ozawa *** to the TG-DSC curves of magnesium sulfide cement,the thermal decomposition reaction process can be divided into five stages under normal *** DSC curve was processed by Kinssinger method and Dolye-Ozawa method,and the kinetic analysis was carried out to calculate the 517 phase activation energy of magnesium sulfide *** three stages correspond to different activation ***,flame retardant mechanism and thermal decomposition mechanism of magnesium sulfide cement based materials are deduced.

关键词： magnesium sulfide cement comprehensive thermal analysis nonisothermal dynamics 517 phase

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Semi-Global Leaderless Consensus of Linear Multi-agent Systems with Actuator and Communication Constraints

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Journal of Systems Science & Complexity 2020年第4期33卷 882-902页

作者： WANG Jian SHI Liangren guan Xinping Department of Automation and Key Laboratory of System Control and Information Processing of Ministry of EducationShanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of Navigation and Location-based Services and Academy of Information Technology and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This paper studies the leaderless consensus problems of multi-agent systems with input saturation and intermittent communication over directed networks. Both the state feedback and the output feedback consensus algorithms are developed based on low gain feedback approach. The convergence of the trajectories of all agents can be achieved by these proposed algorithms, if the communication topology has a directed spanning tree, and the intermittent communication period T and time rate ρ are larger than their associated threshold values. Simulation examples are provided to verify the theoretical results.

关键词： agent directed communication

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A simulation-based emergency force planning method for social security events

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Journal of Systems Engineering and Electronics 2023年第1期34卷 141-148页

作者： YANG Xuesheng WANG Yingli guan Yong War Studies Institute Academy of Military ScienceBeijing 100091China Strategic Assessments and Consultation Institute Academy of Military ScienceBeijing 100091China

The occurrence of social security events is uncertain, and the distribution characteristics are highly complex due to a variety of external factors, posing challenges to their rapid and effective handling. The scientific and reasonable requirement evaluation of the emergency force to deal with social security events is very urgent. Based on data analysis, this paper uses the neural network, operational research, modelling and simulation to predict and analyze social security events, studies the usage rule of emergency force and deployment algorithm, and conducts simulation experiments to evaluate and compare the different force deployment schemes for selection.

关键词： social security emergency force simulation force deployment

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Rare-earth mediated dihydrogen activation and catalytic hydrogenation

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Journal of Rare Earths 2021年第9期39卷 1017-1023页

作者： Yiwen guan Erli Lu Xin Xu Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China School of Natural and Environmental Sciences Newcastle UniversityKing's RoadNewcastle Upon TyneNE17RUUK

This review covers H-H bond cleavage of dihydrogen(H2)mediated by structurally well-defined rareearth metal(scandium,yttrium and lanthanides)complexes,and their applications in homogenous catalysis,such as catalytic hydrogenation of unsaturated organic *** on the mechanism of the H-H bond cleavage,this review is organized in two parts:(1)σ-bond metathesis,and(2)non-σ-metathesis H2 *** latter is a new trend in this research field and is the emphasis of this *** H2 into inorganic rare-earth polyhydride complexes,albeit their potential applications as hydrogen-storage materiel,is not in the scope of this review.

关键词： Rare earths Dihydrogen activation Hydrogenation Homogeneous catalysis Cooperative effect

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Condensation behavior of gaseous phase during transported in the near-substrate boundary layer of plasma spray-physical vapor deposition

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Journal of Materials Science & Technology 2021年第8期67卷 127-134页

作者： Mei-Jun Liu guan-Jun Yang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi'an fiaotong UniversityXi’anShaanxi710049PR China

Plasma spray-physical vapor deposition(PS-PVD)has exhibited the potential ability to prepare columnar structures for advanced thermal barrier coatings(TBCs).The coating structure is nominally affected by operating parameters,but it is controlled by the type of deposition unit actually and *** order to realize the columnar structure deposited by gaseous phase units,the transition behavior of gaseous phase units to clusters must be fundamentally *** work investigated the transport process of gaseous phase units in the PS-PVD near-substrate boundary layer along with the condensation *** Monte Carlo method was used to examine the transport process and condensation behavior of gaseous phase units under different scale boundary *** results show that it is easier to form more numerous larger clusters at the edge of the plasma jet than at the *** on the understanding of the changes in deposition unit caused by the condensation of gaseous phase in the near-substrate boundary layer of PS-PVD,an outlook towards TBCs with different structures is *** it is in good agreement with the experimental data.

关键词： Condensation behavior Transport process Cluster Boundary layer PS-PVD

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A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1171-1188页

作者： Wei WEI Feng guan Xin FANG College of Intelligent Science National University of Defense TechnologyChangsha410073China Naval Research Academy Beijing100161China

A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave *** consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and *** bandgap mechanisms,vibration isolation properties,effects of key parameters,and robustness to complex conditions are *** experimentally demonstrated,the wave-insulating isolator can improve the vibration insulation in the ranges of[50 Hz,180 Hz]and[260 Hz,400 Hz]by 15 dB and 25 dB,respectively,in contrast to the conventional isolator with the same first resonant frequency.

关键词： metamaterial and metastructure vibration isolation bandgap wave insulation plate

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Typing Evolving Ambients

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Journal of Shanghai University(English Edition) 2001年第z1期5卷 26-30页

作者： guan Xu-dong Department of Computer Science & Engineering Shanghai Jiao Tong University Shanghai 200030 People's Republic of China

This paper presents a type system that deals with the type evolution problem of the ambient calculus . It breaks the law that the open capability must introduce to the opening process the exact type information of the opened ambient. It can also serve as a general type architecture supporting type evolution. A typical usage of the type system is illustrated in the immobile server example.

关键词： Theory of computation Type system Ambient calculus

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Effect of Ce addition on hot corrosion behaviours of a cast γ'-strengthened Co–Al–W–Mo–Ta–B alloy at 800 ℃

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Progress in Natural Science:Materials International 2022年第4期32卷 463-471页

作者： Qi guan Fei Zhong Jiangbo Sha School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Key Laboratory of Aerospace Materials and Performance (Ministry of Education) College of Chemistry and Materials Science Hubei Engineering University

Hot corrosion behaviours of a novel Co–9Al-4.5W-4.5Mo–2Ta-0.02B alloy doped with 0.01, 0.05, 0.1 and 0.2 at%Ce exposed at 800℃ in a solution of 75%Na2SO4/25%Na Cl were investigated. The alloys comprised a coherentγ-CoSS/γ’-Co3(Al, W) microstructure(0.01Ce and 0.05Ce alloys) and κ-Co3(W, Mo) precipitates(0.1Ce and 0.2Ce alloys) at grain boundaries. Hot corrosion kinetics curves demonstrated the parabolic time dependency profile with two stages: the first parabolic stage is within the beginning ～50 h corrosion and follows by the second parabolic stage. With an increasing nominal Ce content the weight gain of the alloy significantly decreased from approximately 70.1 mg cm-2(0.01Ce) to 40.8 mg cm-2(0.2Ce) when exposed for 100 h. A two-layer corrosion scale formed, and the scale was composed of an outer layer of Co3O4oxide with spinel compounds of Co Al2O4,CoWO4and CoSO4, and an inner γ/needle-like Co3W/sulphide layer adhered to the substrate. Heavy spallation of the corrosion scale occurred in the 0.01Ce～0.1Ce alloys, however, spallation was slight in the 0.2Ce alloy. The excellent corrosion resistance of the 0.2Ce alloy could be attributed mainly to the formation of continuous Al2O3lines in the corrosion scale, as well as the prolongation of the incubation period of the corrosion product spallation.

关键词： Co–Al–W-Based alloys Doping Ce Microstructural evolution Kinetics curves Hot corrosion mechanisms

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Unified Principal S-N Equation for Friction Stir Welding of 5083 and 6061 Aluminum Alloys

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Chinese Journal of Mechanical Engineering 2021年第2期34卷 190-200页

作者： Xiangwei Li Ji Fang Xiaoli guan CRRC QIQIHAR ROLLING STOCK CO. LTDQiqihar 161000China College of Locomotive and Rolling Stock Engineering Dalian Jiaotong UniversityDalian 116028China

With the popularization of friction stir welding(FSW),5083-H321 and 6061-T6 aluminum alloy materials are widely used during the FSW *** this study,the fatigue life of friction stir welding with two materials,i.e.,5083-H321 and 6061-T6 aluminum alloy,are *** tests were carried out on the base metal of these two materials as well as on the butt joints and overlapping FSW *** principle of the equivalent structural stress method is used to analyze the FSW test data of these two *** fatigue resistances of these two materials were com-pared and a unified principal S-N curve equation was *** key parameters of the unified principal S-N curve obtained by fitting,Cd is 4222.5,and h is 0.2693.A new method for an FSW fatigue life assessment was developed in this study and can be used to calculate the fatigue life of different welding forms with a single S-N *** main fatigue tests of bending and tension were used to verify the unified principal S-N curve *** results show that the fatigue life calculated by the unified mean 50%master S-N curve parameters are the closest to the fatigue test *** reliability,practicability,and generality of the master S-N curve fitting parameters were verified using the test *** unified principal S-N curve acquired in this study can not only be used in aluminum alloy materials but can also be applied to other materials.

关键词： 5083 and 6061 aluminum alloy Friction stir welding Master S-N curve Fatigue life

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