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Flux characteristics of total dissolved iron and its species during extreme rainfall event in the midstream of the Heilongjiang River

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Journal of Environmental Sciences 2015年第4期27卷 74-80页

作者： Jiunian guan Baixing Yan Hui Zhu Lixia Wang Duian Lu long Cheng Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and Agroecology Chinese Academy of Sciences University of Chinese Academy of Sciences

The occurrence of extreme rainfall events and associated flooding has been enhanced due to climate changes, and is thought to influence the flux of total dissolved iron（TDI） in rivers considerably. Since TDI is a controlling factor in primary productivity in marine ecosystems, alteration of riverine TDI input to the ocean may lead to climate change via its effect on biological productivity. During an extreme rainfall event that arose in northeastern China in 2013, water samples were collected in the midstream of the Heilongjiang River to analyze the concentration and species of TDI as well as other basic parameters. The speciation of TDI was surveyed by filtration and ultrafiltration *** with data monitored from 2007 to 2012, the concentration of TDI increased significantly during this event, with an average concentration of 1.11 mg/L, and the estimated TDI flux reached 1.2 × 10^5 tons, equaling the average annual TDI flux *** analysis revealed that low-molecular-weight complexed iron was the dominant species, and the impulse of TDI flux could probably be attributed to the hydrological connection to riparian wetlands and iron-rich terrestrial runoff. Moreover, dissolved organic matter played a key role in the flux, species and bioavailability of TDI. In addition,there is a possibility that the rising TDI flux could further influence the transport and cycling of nutrients and related ecological processes in the river, estuary coupled with the coastal ecosystems, which merits closer attention in the future.

关键词： Total dissolved iron Extreme rainfall event Midstream of the Heilongjiang River Flux

Design and Analysis of Gecko-like Robot

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Chinese Journal of Mechanical Engineering 2011年第2期24卷 224-236页

作者： MENG Cai WANG Tianmiao guan Shengguo ZHANG long WANG Jing LI Xiaohu School of Astronautics Beihang University Beijing 100191 China School of Mechanical Engineering andAutomation Reihang University Beijing 100191 China School of Mechanical Engineering Beijing University of Science and Technology Beijing 100083 China

Gecko-like robot（Geckobot）,an important branch of bionic robotics,is a robot that simulates gecko＇s capacity to climb walls and *** work environment of the traditional wall-climbing robot is greatly limited as the moving structure and adsorption principle of the robot have nothing to do with the real ***,the adsorption principle and moving mode of the real gecko can provide a new way to break through the restrictions of the traditional wall-climbing *** by the moving mechanism of geckos, this paper develops the Geckobot with motile *** types of Geckobots are addressed：one with compliant flat bar as the body,and the other with prismatic joint as the *** compliant body not only resembles the moving mode of the real gecko body,but also simplifies the Geckobot＇s *** prismatic joint body is used to adapt the change of body length in ground-to-wall transition. The gait planning on the plane and the transition between perpendicular intersectional planes is discussed,with an emphasis on the analysis of the kinematics degree of freedom（DOF） and body *** pattern generator（CPG） neural network is realized in LabVIEW and utilized to control Geckobot＇s *** CPG scheme in Lab VIEW is given,and how CPG is used to control Geckobot to turn or move forward is *** are conducted in ADAMS to verify the feasibility of the structure design and gait planning and to acquire some parameters for practical Geckobot *** experiment with Geckobot-Ⅰand Geckobot-Ⅱon their crawling capacity on the plane and the ground-to-wall transition finds that the robot can complete the crawling movement and ground-to-wall transition,verifying the feasibility of the structure design,gait planning and the CPG motion *** Geckobot structure design approach,gait planning and the CPG motion control presented would be useful for the research on wall-climbing robots.

关键词： gecko-like robot structure design gait planning ground-to-wall transition central pattern generator

Full-scale experiment for segmental linings of deep-buried shield tunnels bearing high inner water pressure:Comparison of mechanical behaviors of continuous-and stagger-jointed structures

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Underground Space 2023年第1期8卷 252-266页

作者： long Zhou Yi Shen Linxing guan Zhiguo Yan Wei Sun Yaoliang Li College of Civil Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Shanghai Municipal Engineering Design Institute(Group)Co.Ltd. Shanghai 200092China Shanghai Foundation Engineering Group Co.Ltd. Shanghai 200002China

Full-scale loading tests were performed on shield segmental linings bearing a high earth pressure and high inner water pressure,focus-ing on the effects of the inner water load and assembly manner on the mechanical properties of the segmental *** test results indicate that the deep-buried segmental linings without inner pressure have a high safety *** the action of high inner water pressure,the lining deformation will increase with the reduction of the safety reserve,caused by the significant decrease in the axial force in the *** the bending moment at the segmental joints is transferred to the segment sections in the adjacent ling rings,the convergence deformation,openings of segmental joints,and bolt strains are smaller for the stagger-jointed lining than those for the continuous-jointed lining;however,dislocations appear in the circumferential joints owing to the stagger-jointed *** it significantly improves the mechanical performance of the segmental lining,stagger-jointed assembly results in compromising the water-proofing safety of circumferential *** stagger-jointed assembly manner can be considered to improve the service performance of shield tunnels bearing high inner water pressure on the premise that circumferential joint waterproofing is satisfied.

关键词： Shield tunnel Inner water pressure Continuous-jointed lining Stagger-jointed lining Full-scale experiment

Analysis of meso-inhomogeneous deformation on a metal material surface under low-cycle fatigue

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Acta Mechanica Solida Sinica 2017年第6期30卷 557-572页

作者： Gui-long Liu Ke-Shi Zhang xian-Ci Zhong Jiann Woody Ju College of Civil Engineering and Architecture Guangxi University Key Lab of Disaster Prevention and Structural Safety guangxi Key Lab Disaster Prevention and Engineering Safety Nanning 530004 China College of Mathematics and Information Science Guangxi University Nanning 530004 China Department of Civil and Environmental Engineering University of California Los Angeles CA 90095-1593 USA

A polycrystalline Voronoi aggregation with a free surface is applied as the representative volume element（RVE）of the nickel-based GH4169 *** the plastic deformation mechanism at the grain level and the Bauschinger effect,a crystal plasticity model reflecting the nonlinear kinematic hardening of crystal slipping system is *** microscopic inhomogeneous deformation during cyclic loading is calculated through numerical simulation of crystal *** deformation inhomogeneity on the free surface of the RVE under cyclic loading is described respectively by using the following parameters：standard deviation of the longitudinal strain in macro tensile direction,statistical average of first principal strains,and standard deviation of longitudinal *** relationship between the fatigue cycle number and the evolution of inhomogeneous deformation of the material’s free surface is *** research finds that：（1）The inhomogeneous deformation of the material free surface is significantly higher than that of the RVE inside;（2）the increases of the characterization parameters of inhomogeneous deformation on the free surface with cycles reflect the local maximum deformation of the RVE growing during cyclic loading;（3）these parameters can be used as criteria to assess and predict the low-cycle fatigue life rationally.

关键词： Inhomogeneous deformation Surface Grain-level Crystal plasticity Low-cycle fatigue Life prediction

Focusing with the decomposition of the time reversal operator method in noisy environments

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第7期10卷 997-1008页

作者： Chun-xiao LI Jian-long LI xian-yi GONG Ming-fei GUO Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China Hangzhou Applied Acoustics Research Hangzhou 310012 China MOE Key Laboratory of Mechanical Manufacture and Automation Zhejiang University of Technology Hangzhou 310014 China

This paper presents a detailed analysis of the effects of noise (reverberation) on the focusing performance of de-composition of the time reversal operator (DORT) in a noise-limited case and in a reverberation-limited case, respectively. Quantitative results obtained from simulations and experiments are presented. The results show the DORT method can be effi-ciently applied to target detection with enough source level to yield significant backscatter. For a target placed on the bottom, the influence of the reverberation on the focusing performance is slight. However, distinguishing between a target and constant backscattering returning from strong local clutter on the bottom (false alarms) needs further research.

关键词： Decomposition of the time reversal operator (DORT) Time reversal mirror Retrofocusing performance

Halogen-bonded Cocrystal Based on Tetrathiafulvalene Derivatives

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Chinese Journal of Structural Chemistry 2021年第10期40卷 1277-1283页

作者： ZHAO long CHEN guan-Fan WEN Yi-Hang XIAO Xun-Wen School of Chemistry and Chemical Engineering Hunan University of Science and TechnologyXiangtan 411201China College of Chemistry and Life Science Zhejiang Normal UniversityJinhua 321004China School of Material and Chemical Engineering Ningbo University of TechnologyNingbo 315211China

In this paper, two cocrystals 1 and 2 with the same chemical composition [L1.L2 ](L1 = bis(4’-pyridyl)-TTF, L2 = 4,4’-diiodophenyl) were synthesized by slow diffusion with different solvent systems. Cocrystals 1 and 2 were characterized by single-crystal X-ray and the purity of these two cocrystals was confirmed by PXRD data. The photocurrent responses of these two cocrystals were also tested. Only cocrystal 1 could generate photocurrent signal when exposed to light. From the crystal structure analysis, the possible reason may come from the different biphenyl conformations in L2.

关键词： tetrathiafulvalene crystal structure halogen bonding photocurrent responses

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Maximum Likelihood Estimator of the Location Parameter under Moving Extremes Ranked Set Sampling Design

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Acta Mathematicae Applicatae Sinica 2021年第1期37卷 101-108页

作者： Wang-xue CHEN Chun-xian long Rui YANG Dong-sen YAO Department of Mathematics and Statistics Jishou UniversityJishou 416000China

Cost effective sampling design is a problem of major concern in some experiments especially when the measurement of the characteristic of interest is costly or painful or time *** the current paper,a modification of ranked set sampling(RSS)called moving extremes RSS(MERSS)is considered for the estimation of the location parameter for location family.A maximum likelihood estimator(MLE)of the location parameter for this family is studied and its properties are *** prove that the MLE is an equivariant estimator under location *** order to give more insight into the performance of MERSS with respect to(w.r.t.)simple random sampling(SRS),the asymptotic efficiency of the MLE using MERSS *** using SRS is computed for some usual location *** relative results show that the MLE using MERSS can be real competitors to the MLE using SRS.

关键词： ranked set sampling moving extremes ranked set sampling maximum Likelihood estimator equivariant estimator fisher information number

Accumulated-state-error-based event-triggered sampling scheme and its application to H∞ control of sampled-data systems

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Science China(Information Sciences) 2024年第6期67卷 328-341页

作者： xian-Ming ZHANG Qing-long HAN Bao-Lin ZHANG Xiaohua GE Dawei ZHANG School of Science Computingand Engineering TechnologiesSwinburne University of Technology College of Automation and Electronic Engineering Qingdao University of Science & Technology School of Mathematics Shandong University

This paper is concerned with event-triggered H∞control of sampled-data systems. Its novelties lie in three aspects:（i） A novel accumulated-state-error-based event-triggered scheme is introduced by comparing the integral of the state error from tk to t with the system state sampled at tk. This condition works well due to the fact that the so-called Zeno behaviour does not occur.（ii） A novel Lyapunov functional is constructed to establish a criterion to ensure some certain H∞performance of the closed-loop system. This Lyapunov functional is dependent on the integral of the state error involved in the event-triggered scheme.（iii） Under the event-triggered sampling scheme, suitable state-feedback controllers can be designed rather than be given a priori. Moreover, a self-triggered implementation of the proposed event-triggered sampling scheme is presented as well. Finally, a batch reactor model and an inverted pendulum system are given to demonstrate the effectiveness of the proposed method.

关键词： event-triggered sampling self-triggered implementation H ∞ control looped-functional

Bilateral Teleoperation of Multiple Agents with Formation Control

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IEEE/CAA Journal of Automatica Sinica 2014年第2期1卷 141-148页

作者： Jing Yan xian Yang Cailian Chen Xiaoyuan Luo Xinping guan Institute of Electrical Engineering Yanshan University Department of Automation Shanghai Jiao Tong Universityand Key Laboratory of System Control and Information ProcessingMinistry of Education of China

This paper studies the formation problem for multislave teleoperation system over general communication networks,where multiple mobile slave agents are coupled with a single master robot. The forward and backward network transmission time delays are assumed to be asymmetric and *** to the quantization in the network, a dynamic quantization strategy is provided to quantize the output signals of the master robot and slave agents before transmitting. Then, a novel masterslave protocol is designed to achieve the formation task under variable time delays and quantization. Additionally, the sufficient conditions for stability are presented to show that the formation protocol can stabilize the master-slave system under variable time delays and quantization. Finally, simulation are performed to show effectiveness of the main results.

关键词： Robots Quantization (signal) Delay effects Protocols Stability analysis Delays Multi-agent systems