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Characterization of volatile organic compounds in the urban area of Beijing from 2000 to 2007

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Journal of Environmental Sciences 2012年第1期24卷 95-101页

作者： Yuesi Wang xiyan ren Dongsheng Ji Junqang Zhang Jie Sun Fankun Wu State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 10083China

Beijing is one of the most polluted cities in the *** this study,the long-term and continuous measurements of volatile organic compounds （VOCs） in the urban area of Beijing,specifically at Beijing 325 m Meteorological Tower,were conducted from 2000 to *** annual record of VOC trends exhibited in two different phases was separated in *** show that VOC concentrations increased from 2000 to 2003 due to the abrupt increase in vehicle ***,since 2003,there had been a decrease in VOCs concentrations as the policy on gasoline and air pollution was ***,benzene,and i-pentane are the chemicals that abound in and are directly related to vehicle activity,such as in vehicle exhaust and gasoline ***,records indicate that there had been seasonal variation in VOCs levels in that VOCs level in summer is higher than that in *** such,temperature is considered to significantly contribute to VOCs in *** also show that VOCs level was high in the morning and during rush hours in the *** contrast,VOCs level was low during midday due to photochemical destruction with OH radical and dilution *** this study,a particular benzene to toluene ratio range （0.4–1.0） was used as the indicator of air propelled by vehicular *** also applied the correlation coefficients between BTEX and i-pentane to evaluate evaporation influence to ambient BTEX in the Beijing urban area.

关键词： VOCs air pollution continuous measurements variations BTEX benzene to toluene ratio

Loss coefficient of nitrogenous non-point source pollution under various precipitation conditions

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Frontiers of Environmental Science & Engineering 2008年第2期2卷 230-235页

作者： Hongguang CHENG Fanghua HAO xiyan ren Shengtian YANG Wen XIONG Shaoping LEI School of Environment Beijing Normal UniversityState Key Laboratory of Water Environment SimulationBeijing 100875China The Water Resources Protection Scientific Research Institute of the Yangtze River Wuhan 430051China

In this study,calibrations of non-point source(NPS)pollution models are performed based on Black River basin historical real-time runoff data,sedimentation record data,and NPS sources survey *** concept of NPS loss coefficient for the watershed or the loss coefficients(LC)for simplicity is brought up by examining NPS build-up and migration processes along riverbanks in natural river *** historical data is used for determining the nitrogenous NPS loss coefficient for five land use types including farmland,urban land,grassland,shrub land,and forest under different precipitation *** comparison of outputs from Soil and Water Assessment Tool(SWAT)model and coefficient export method showed that both methods could obtain reasonable *** high Pearson correlation coefficient(0.94722)between those two sets of calculation results justified the consistency of those two *** result in the study is that different combinations of precipitation condition and land use types could significantly affect the calculated loss *** for the adsorptive nitrogen,the order of impact on LC for different land use types can be sorted as:farm *** *** *** while the order was *** *** *** land for soluble nitrogen.

关键词： non-point source pollution land uses loss coefficient Heihe River Basin

A FAS approach for stabilization of generalized chained forms: part 1. Discontinuous control laws

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Science China(Information Sciences) 2024年第2期67卷 118-143页

作者： Guang-ren DUAN Center for Control Theory and Guidance Technology Harbin Institute of Technology Center for Control Science and Technology Southern University of Science and Technology

In this paper, a type of general nonholonomic systems is proposed, which contains both the Brockett’s two example systems, and their extended n-dimensional chained forms, as special cases. For the stabilization of such systems, a stabilizing controller is proposed based on the fully actuated system(FAS)approach, which is discontinuous at the origin but time-invariant when the open-loop system is time-invariant,and drives the feasible trajectories of the system to the origin exponentially. Furthermore, the proposed FAS approach is also extended to the sub-normal system case and the time-delay system case.

关键词： nonholonomic systems feedback stabilization exponential convergence sub-fully actuated systems time-delay systems

A FAS approach for stabilization of generalized chained forms: part 2. Continuous control laws

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Science China(Information Sciences) 2024年第3期67卷 114-135页

作者： Guang-ren DUAN Center for Control Theory and Guidance Technology Harbin Institute of Technology Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and Technology

In this paper, continuous time-varying stabilizing controllers for the type of general nonholonomic systems proposed and treated in part 1 are designed using the fully actuated system(FAS) approach. The key step is to differentiate the first scalar equation, and by control of the obtained second-order scalar system, a proportional plus integral feedback form for the first control variable is obtained. With the solution to this designed second-order scalar system, the rest equations in the nonholonomic system form an independent time-varying subsystem which is then handled by the FAS approach. The overall designed controller contains an almost arbitrarily chosen design parameter, and is proven to guarantee the uniformly and globally exponential stability of the closed-loop system. The proposed approach is simple and effective,and is demonstrated with a practical example of ship control.

关键词： nonholonomic systems feedback stabilization fully actuated systems Lyapunov stability continuous controllers

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Resilient control of flexible hypersonic vehicles against unmatched distributed faults

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Chinese Journal of Aeronautics 2024年第5期37卷 60-70页

作者： Dong ZHAO Wenjing ren School of Artificial Intelligence Anhui UniversityHefei 230601China Key Laboratory of System Control and Information Processing Ministry of EducationShanghai Jiao Tong UniversityShanghai 200240China School of Electrical Engineering and Automation Hefei University of TechnologyHefei 230009China

This paper studies a robust fault compensation and vibration suppression problem of flexible hypersonic *** controlled plant is represented by a cascade system composed of a nonlinear Ordinary Differential Equation(ODE)and an Euler-Bernoulli Beam Equation(EBBE),in which the vibration dynamics is coupled with the rigid dynamics and suffers from distributed faults.A state differential transformation is introduced to transfer distributed faults to an EBBE boundary and a longitudinal dynamics is refined by utilizing T-S fuzzy IF-THEN rules.A novel T-S fuzzy based fault-tolerant control algorithm is developed and related stability conditions are *** robust exponential stability and well-posedness are proved by using the modified l_(0)-semigroup based Lyapunov direct approach.A simulation study on the longitudinal dynamics of flexible hypersonic vehicles effectively verifies the validity of the developed theoretical results.

关键词： Flexible hypersonic vehicles ODE-EBBE cascade Robust exponential stability Unmatched distributed fault compensation Vibration suppression

Global Solvability for a Predator-Prey Model with Prey-Taxis and Rotational Flux Terms

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 297-318页

作者： Guoqiang ren Bin LIU School of Mathematics and Statistics Huazhong University of Science and Technology Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong Universityof Science and Technology

In this paper the author investigates the following predator-prey model with prey-taxis and rotational?ux terms■in a bounded domain with smooth *** presents the global existence of generalized solutions to the model... 详细信息

关键词： Predator-prey Prey-taxis Giopal existence Kotational flnux

Progress in modeling and control of probe-and-drogue autonomous aerial refueling

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Chinese Journal of Aeronautics 2024年第5期37卷 6-26,I0001页

作者： Jinrui ren Quan QUAN School of Automation Xi’an University of Posts&TelecommunicationsXi'an 710072China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

By refueling aircraft while they are in flight,aerial refueling is an efficient technique to extend their endurance and *** Aerial Refueling(AAR)is anticipated to be used to complete aerial refueling for unmanned *** are three aerial refueling methods:the Probe-and-Drogue Refueling(PDR)refueling method,the flying-boom refueling method,and the boom-drogue-adapter refueling *** paper considers the PDR approach,the most challenging of the three,because the flexible hose-drogue assembly has fast dynamics and is susceptible to various kinds of winds,which makes the probe docking with the drogue *** is divided into four phases,namely the rendezvous phase,joining phase,refueling phase,and reform phase,with the refueling phase being the most *** controller design faces the greatest challenge during the docking control of the refueling phase since it calls for a high level of safety,precision,and *** a result,the modeling and control issues encountered during the refueling phase are typical and *** fundamental idea of AAR is presented in the paper first,after which the characteristics and requirements of AAR are *** progress in modeling and control techniques for the AAR’s refueling phase is then systematically ***,potential future work for high safety,precision,and efficiency requirements is examined and suggested.

关键词： Aerial refueling Probe-and-drogue refueling Docking Flight controlsystems Unmanned Aerial Vehicles

Envisioning Water-Resilient Cities Through the Lens of Blue-Green-Grey Solutions

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Engineering 2024年第5期36卷 1-2页

作者： Nan-Qi ren Glen Daigger School of Civil and Environmental Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150090China Department of Civil and Environmental Engineering University of MichiganAnn ArborMI 48109USA

Cities are dynamic systems,and the urban water systems within them can be evolved to provide water services to both humans and the environment while also enhancing the broader urban *** is done by embracing innovation and technological advancement while focusing on increased service to the human population and the local and broader *** the contemporary era,characterized by the rise of low-carbon and intelligent technologies,the swift pace of socioeconomic expansion highlights the critical need to address issues of urban water security and environmental *** escalating resource and environmental constraints,adopting holistic blue-green-grey strategies becomes imperative for the sustainable governance of urban water *** integrated approach is needed to navigate the intricate challenges of urban water dynamics while fostering enhanced ecological performance and resilience.

关键词： services urban advancement

Inter-well internal resonance analysis of rectangular asymmetric cross-ply bistable composite laminated cantilever shell under transverse foundation excitation

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1353-1373页

作者： Lele ren Wei ZHANG Yufei ZHANG State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Department of Mechanics Guangxi University Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures College of Mechanical Engineering Beijing University of Technology

The chaotic dynamic snap-through and complex nonlinear vibrations are investigated in a rectangular asymmetric cross-ply bistable composite laminated cantilever shell, in cases of 1 : 2 inter-well internal resonance and primary resonance. The transverse foundation excitation is applied to the fixed end of the structure, and the other end is in a free state. The first-order approximate multiple scales method is employed to perform the perturbation analysis on the dimensionless two-degree-of-freedom ordinary differential motion control equation. The four-dimensional averaged equations are derived in both polar and rectangular coordinate forms. Deriving from the obtained frequency-amplitude and force-amplitude response curves, a detailed analysis is conducted to examine the impacts of excitation amplitude, damping coefficient, and tuning parameter on the nonlinear internal resonance characteristics of the system. The nonlinear softening characteristic is exhibited in the upper stable-state, while the lower stable-state demonstrates the softening and linearity characteristics. Numerical simulation is carried out using the fourth-order Runge-Kutta method, and a series of nonlinear response curves are plotted. Increasing the excitation amplitude further elucidates the global bifurcation and chaotic dynamic snap-through characteristics of the bistable cantilever shell.

关键词： 74K10 bistable composite laminated cantilever shell chaotic dynamic snap-through complex nonlinear vibration inter-well internal resonance O322 primary resonance