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In-Plane Semi-Linear Cloaks with Arbitrary Shape

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Acta Mechanica Solida Sinica 2019年第3期32卷 277-286页

作者： Dengke Guo Zheng Chang Gengkai Hu Key Laboratory of Dynamics and control of Flight Vehicle Ministry of Education School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China College of Science China Agricultural University Beijing 100083 China

Soft materials with semi-linear strain energy function can be used as smart transformation media to manipulate elastic waves via finite pre-deformation. However, the intrinsic cons train ts involved in such materials limit the shapes of t ransformation devices to very sim - pie cases. In this work, combining theoretical and numerical analyses, we report an approach of achieving the in-plane elastodynamic cloak with arbitrary shape. We demonstrate that with the appropriate out-of^plane st retch applied on the semi-linear material, cloaking effec t can be achieved for both P- and SV-waves in the symmetrie plane of a 3D domain, and the performance of the cloak with arbitrary cross section can be guaranteed for relatively small in-plane rot at ion. In addition, we propose an empirical formula to predic t the deformation limit of the cloaks with semi-linear materials. This work may stimulate the experimental research on softmatter- based transformation devices. Potential applications can be anticipated in nondestructive testing, structure impact protection, biomedical imaging and soft robotics.

关键词： Elastic waves Cloak Hyperelasticity Semi-linear Arbitrary shape

Asynchronous H_∞ control for Unmanned Aerial Vehicles: Switched Polytopic System Approach

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IEEE/CAA Journal of Automatica Sinica 2015年第2期2卷 207-216页

作者： Zhaolei Wang Qing Wang Chaoyang Dong School of Automation Science and Electrical engineering Beijing University of Aeronautics and Astronautics beijing Aerospace Automatic {1. institute School of Aeronautical Science and engineering Beijing University of Aeronautics and Astronautics

This study is concerned with the H∞control for the full-envelope unmanned aerial vehicles (UAVs) in the presence of missing measurements and external disturbances. With the dramatic parameter variations in large flight envelope and the locally overlapped switching laws in flight, the system dynamics is modeled as a locally overlapped switched polytopic system to reduce designing conservatism and solving complexity. Then, considering updating lags of controller's switching signals and the weighted coefficients of the polytopic subsystems induced by missing measurements, an asynchronous H∞control method is proposed such that the system is stable and a desired disturbance attenuation level is satisfied. Furthermore, the sufficient existing conditions of the desired switched parameter-dependent H∞controller are derived in the form of linear matrix inequality (LMIs) by combining the switched parameter-dependent Lyapunov function method and average dwell time method. Finally, a numerical example based on a highly maneuverable technology (HiMAT) vehicle is given to verify the validity of the proposed method. © 201. Chinese Association of Automation.

关键词： Flight envelopes Linear matrix inequalities Lyapunov functions Numerical methods Robust control Robustness (control systems) Unmanned aerial vehicles (UAV) Vehicles

Whole-Process Pollution control for Cost-Effective and Cleaner Chemical Production A Case Study of the Tungsten Industry in China

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engineering 2019年第4期5卷 768-776页

作者： Hongbin Cao He Zhao Di Zhang Chenming Liu Xiao Lin Yuping Li Pengge Ning Jiajun Sun Yi Zhang Zhi Sun beijing {1. Research Center of Process Pollution control and National {1. Laboratory for Hydrometallurgical Cleaner Production Technology Division of Environment Technology and EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China

In this research,a methodology named whole-process pollution control(WPPC)is demonstrated that improves the effectiveness of process *** methodology considers waste/emission treatment as a step of the whole production process with respect to the minimization of cost and environmental impact for the whole *** following procedures are introduced in a WPPC process optimization:①a material and energy flow investigation and optimization based on a systematic understanding of the distribution and physiochemical properties of potential pollutants;②a process optimization to increase the utilization efficiency of different elements and minimize pollutant emissions;and③an evaluation to reveal the effectiveness of the optimization *** production of ammonium paratungstate was chosen for the case *** factors of the different optimization schemes-namely the cost-effectiveness factor and the environmental impact indicator-were evaluated and *** research demonstrates that by considering the nature of potential pollutants,technological innovations,economic viability,environmental impacts,and regulation requirements,WPPC can efficiently optimize a metal production process.

关键词： Whole-process pollution control Process optimization Industrial pollution Tungsten

Floating plants reduced methane fluxes from wetlands by creating a habitat conducive to methane oxidation

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Journal of Environmental Sciences 2024年第1期135卷 149-160页

作者： Fuwei Wang Songhe Zhang Xiuren Hu Xin Lv Min Liu Yu Ma Benjamin Manirakiza Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Ministry of EducationHohai UniversityNanjing 210098China College of Environment Hohai UniversityNanjing 210098China China Machinery International engineering Desigh and Research {1. co. Ltd.East China Regional CenterNanjing 210008China

Wetlands are one of the important natural sources of atmospheric methane (CH_4),as an important part of wetlands,floating plants can be expected to affect methane ***,the effects of floating plants on methane release are *** this study,methane fluxes,physiochemical properties of the overlying water,methane oxidation potential and rhizospheric bacterial community were investigated in simulated wetlands with floating plants Eichhornia crassipes,Hydrocharis dubia,and Trapa *** found that ***,***,and *** plants could inhibit 84.31.-97.31.,4.98%-88.91.and 43.62%-92.51.of methane fluxes at interface of water-atmosphere compared to control,*** fluxes were negatively related to nutrients concentration in water column but positively related to the aerenchyma proportions of roots,stems,and *** the same biomass,root of *** (36.44%) had the highest methane oxidation potential,followed by *** (1..99%) and *** (1..23%).Forty-five bacterial phyla in total were identified on roots of three plants and 7 bacterial genera (2.1.%-3.33%) were known *** I methanotrophs accounted for 95.07%of total *** pmoA gene abundances ranged from 1.90×1.^(1.)to 2.30×1.^(1.)copies/g fresh weight of root *** of pmoA gene was significantly positively correlated with environmental *** (5.40%) and methanotrophy (3.75%) function were closely related to methane *** study highlights that floating plant restoration can purify water and promote carbon neutrality partially by reducing methane fluxes through methane oxidation in wetlands.

关键词： Floating plants Methane fluxes Aerenchyma Methanotrophs

Mechanism analysis of regulating Turing instability and Hopf bifurcation of malware propagation in mobile wireless sensor networks

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Chinese Physics B 2024年第6期33卷 125-140页

作者：黄习习肖敏 Leszek Rutkowski 包海波黄霞曹进德 College of Automation&College of Artificial Intelligence Nanjing University of Posts and TelecommunicationsNanjing 210023China Systems Research institute of the Polish Academy of Sciences 01-447 WarsawPoland College of Electrical engineering and Automation Shandong University of Science and TechnologyQingdao 266590China School of Mathematics Southeast UniversityNanjing 210096China

A dynamical model is constructed to depict the spatial-temporal evolution of malware in mobile wireless sensor networks(MWSNs). Based on such a model, we design a hybrid control scheme combining parameter perturbation and state feedback to effectively manipulate the spatiotemporal dynamics of malware propagation. The hybrid control can not only suppress the Turing instability caused by diffusion factor but can also adjust the occurrence of Hopf bifurcation induced by time delay. Numerical simulation results show that the hybrid control strategy can efficiently manipulate the transmission dynamics to achieve our expected desired properties, thus reducing the harm of malware propagation to MWSNs.

关键词： mobile wireless sensor networks reaction-diffusion Hopf bifurcation hybrid control

The adsorption effect of aquaculture residual feed on heavy metals and its impact on microbial metabolism of feed

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Ecological Processes 2024年第2期13卷 246-259页

作者： Sufeng Wang Zijng Wang Wen Zhang Jingshan Li Mingyang Lin Li Chen State Key Laboratory of Metastable Materials Science and Technology Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse Yanshan University Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province College of Biology and Environmental EngineeringZhejiang Shuren University Hebei Ocean & Fisheries Science Research institute

Background Intensive and large-scale aquaculture has a high biological density, and a large amount of artificial feed must be provided. As a result, residual feed would be discharged into natural water bodies with water exchange. Due to heavy metal pollution in surface water, residual feed may adsorb heavy metals in the water, affecting the subsequent microbial degradation of feed and the restoration of the water environment. The combined ecological impacts of these two types of pollution urgently need to be *** This study explored the adsorption effect of residual feed on heavy metals and its impact on microbial degradation of residual feed. The results showed that both the insoluble component（mainly fiber, ash, and ether extract, abbreviated as FAE） and soluble component（soluble protein and starch） of the feed had adsorption effects on heavy metals. As the salinity increased, the adsorption capacity of Cu2+and Cd2+decreased, while the adsorption effect on Pb2+was not changed significantly. The adsorption of heavy metals by residual feed could affect the biological degradation of residual feed. The residual feed could adsorb heavy metals and bacterial cells simultaneously, forming FAE-B（bacteria）-S（starch）-Pr（protein）-metal adsorption complex. This adsorption effect could reduce the negative impact of heavy metals on microbial degradation of residual feed. The simulated degradation experiments in actual water bodies also confirmed this. However, the accumulation of heavy metals in residual feed may bring negative effects, such as being consumed by aquatic organisms and entering the food *** The results of this study provide a basis for the collection and centralized treatment of residual feed in aquaculture, as well as the control and remediation of residual feed pollution in natural water bodies.

关键词： Residual feed Adsorption complex Feed pollution Heavy metal

Hybrid event-and time-triggered control for double-integrator heterogeneous networks

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Science China(Information Sciences) 2019年第2期62卷 73-84页

作者： Gaopeng DUAN Feng XIAO Long WANG Center for Systems and control College of Engineering Peking University Research institute of Intelligent {1. and Systems Harbin Institute of Technology

This paper investigates the state consensus for double-integrator networks under heterogeneous interaction topologies. For double-integrator networks, the setting of heterogeneous topologies means that position and velocity information flows are modeled by two different graphs. The corresponding protocol proposed in this paper is based on edge-event-triggered control. The events based on position information are irrelevant to velocity information and independent of the events based on velocity information. And for different edges, the corresponding events are activated independently of each other. Once an event occurs,the agents connected by the associated edge will sample their corresponding relative state information and update their corresponding controllers. Furthermore, under the presented event-triggering rules, the state consensus of double-integrator networks can be achieved by designing appropriate parameters. In addition,the proposed protocol with the event-triggering rules can effectively improve the system performance and avoid the occurrence of Zeno behaviors. Finally, a simulation example is worked out to verify the theoretical analysis.

关键词： consensus sampled-data control multi-agent systems edge-event-triggered control heterogeneous networks

Performance evaluation of laponite as a mud-making material for drilling fluids

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Petroleum Science 2019年第4期16卷 890-900页

作者： Zheng-Qiang Xiong Xiao-Dong Li Fan Fu Yan-Ning Li beijing {1. of Exploration engineering

In this study, laponite was tested as a mud-making material for drilling fluids. Laponite is a synthetic smectite clay with a structure and composition closely resembling the natural clay mineral hectorite. Commercially available laponite was characterized by X-ray di ractometry, scanning electron microscopy and infrared spectrometry. Its dispersibility, salt resistance and high-temperature resistance were evaluated. The results showed that laponite possessed superior cation exchange capacity(1.0.4 mmol/1.0 g) with interlayer cations of Na^+ and Li^+. Laponite could easily be dispersed in water to yield increased viscosity with no influence from hydration time or temperature. On the other hand, laponite dispersions displayed an excellent heat resistance, with invariant apparent viscosity at high temperatures. For instance, the apparent viscosity of the2 wt% laponite dispersion underwent changes between 22 and 24 mPa s after hot rolling at 1.0–240 °C for 1. h. Compared to existing mud-making materials, laponite exhibited better mud-making properties. Furthermore, laponite revealed good compatibility with other additives, and the water-based drilling fluids prepared with laponite as mud-making material showed an excellent stability at elevated temperatures and superior performance–cost ratios. Overall, these findings indicated that laponite had an excellent dispersibility at high temperatures and hence would have promising applications as high-temperature mud-making material for preparing water-based drilling fluids designed for ultra-high-temperature environments.

关键词： Laponite Mud-making material Dispersibility High-temperature tolerance Ultra-high-temperature water-based drilling fluids

Two Congruent Semantics for Prolog with CUT

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Journal of Computer Science & Technology 1990年第1期5卷 82-91页

作者：朱明远 beijing {1. of System engineering

The development of a formal semantics for a given programming language can proceed in several stages. At each stage we give an alternative semantic definition of the language, and each definition embodies successively more and more implementation details. Then we formulate and prove at each stage the congruence conditions between successive definitions in the sequence. This paper presents two formal semantics for Prolog with “cut” and shows the congruence condition between them.

关键词： ENVI Prolog Two Congruent Semantics for Prolog with CUT