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Dynamic Modeling and Experiment of a Fish Robot with a Flexible Tail Fin

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Journal of Bionic Engineering 2013年第1期10卷 39-45页

作者： Phi luan Nguyen Van Phu Do Byung Ryong Lee ~ Intelligent Control and Mechatronics Lab School of Mechanical Engineering University of Ulsan Daehak-ro 93 Nam-gu Ulsan 680-749 South Korea School of Mechanical Engineering University of Ulsan Daehak-ro 93 Nam-gu Ulsan 680-749 South Korea

This paper presents the dynamic modeling of a flexible tail for a robotic fish. For this purpose firstly, the flexible tail was simplified as a slewing beam actuated by a driving moment. The governing equation of the flexible tail was derived by using the Euler-Bernoulli theory. In this equation, the resistive forces were estimated as a term analogous to viscous damping. Then, the modal analysis method was applied in order to derive an analytical solution of the governing equation, by which the relationship between the driving moment and the lateral movement of the flexible tail was described. Finally, simulations and experiments were carried out and the results were compared to verify the accuracy of the dynamic model. It was proved that the dynamic model of a fish robot with a flexible tail fin well explains the real behavior of robotic fish in underwater environment.

关键词： robotic fish flexible tail dynamic modeling lateral movement

Transcranial direct current stimulation inhibits epileptic activity propagation in a large-scale brain network model

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Science China(Technological Sciences) 2023年第12期66卷 3628-3638页

作者： YU Ying FAN YuBo HAN Fang luan GuoMing WANG QingYun School of Engineering Medicine Beihang UniversityBeijing 100191China Beihang University Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringKey Laboratory Biomechanics&MechanobiologyMinistry of EducationBeijing 100191China College of Information Science and Technology Donghua UniversityShanghai 201620China Beijing Key Laboratory of Epilepsy Sanbo Brain HospitalCapital Medical UniversityBeijing 100069China Department of Dynamics and Control Beihang UniversityBeijing 100191China Beijing Institute of Brain Disorders Capital Medical UniversityBeijing 100069China

Transcranial direct current stimulation(tDCS)is a noninvasive technique that uses constant,low-intensity direct current to regulate brain *** studies have shown that cathode-tDCS(c-tDCS)is effective in reducing seizure frequency in patients with *** to the heterogeneity and patient specificity of seizures,patient-specific epilepsy networks are increasingly important in exploring the regulatory role of *** this study,we first set the left hippocampus,parahippocampus,and amygdala as the epileptogenic zone(EZ),and the left inferior temporal cortex and ventral temporal cortex as the initial propagation zone(PZ)to establish a large-scale epilepsy network *** we set tDCS cathode locations according to the maximum average energy of the simulated EEG signals and systematically study c-tDCS inhibitory effects on the propagation of epileptic *** results show that c-tDCS is effective in suppressing the propagation of epileptic ***,to consider the patient specificity,we set specific EZ and PZ according to the clinical diagnosis of 6 patients and establish patient-specific epileptic *** find that c-tDCS can suppress the propagation of abnormal activity in most patient-specific epileptic ***,when the PZ is widely distributed in both hemispheres,the treatment effect of c-tDCS is not ***,we propose dual-cathode *** epilepsy models with a wide distribution of PZ,it can inhibit the propagation of epileptiform activity in other nodes except EZ and PZ without increasing the tDCS current *** results provide theoretical support for the treatment of epilepsy with tDCS.

关键词： epilepsy large-scale brain network modeling transcranial direct current stimulation neural mass model

Morphological evolution of the channel-shoal system in the South Channel of the Changjiang Estuary during 1958–2018:Causes and future trends

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Journal of Geographical Sciences 2022年第11期32卷 2291-2310页

作者： luan Hualong YAO Shiming QU Geng LEI Wentao River Research Department Changjiang River Scientific Research InstituteWuhan 430010China

The stability of estuarine channel-shoal systems is important for port utilization,navigation maintenance,habitat protection and ecosystem service *** paper uses the South Channel of the Changjiang(Yangtze River)Estuary as a typical example to investigate the channel-shoal adjustment mechanism and its future *** combined approaches of bathymetric data analysis and process-based modeling(Delft3D)are *** analysis of morphological changes indicates that the South Channel experienced remarkable channel-shoal adjustment during 1958–*** evolution was identified,including shoal migration,incision and emergence under natural conditions before the *** then,fluvial sediment decline and local human intervention have interrupted the periodic *** 1986,as river sediment discharge started to decline,the South Channel converted to net erosion,and both the mid-channel shoal at the bifurcation node and the tail of the Ruifeng Shoal showed significant ***-based hydrodynamic simulations revealed that the northern rotation of the mainstream downstream of Wusong triggered the erosion of the Ruifeng Shoal,while unordered sand mining at the shoal tail in approximately 2002 enhanced shoal *** addition,the self-adjustment of the transverse section shape resulted in abnormal accretion in 2002–***,the South Channel underwent overall erosion as sediment discharge decreased to a low level(<150 Mt/a).Five stages of channel-shoal pattern adjustment and accretion/erosion status during the past 60years were defined,i.e.,the accretion stage(1958–1965),remarkable channel-shoal adjustment stage(1978–1986),slow erosion stage(1986–1997),shoal scour and shrinkage stage(1997–2007)and overall channel-shoal erosion stage(2007–2018).Model prediction of the evolutionary trend indicates that overall erosion within the South Channel is most likely to continue in 2015–*** adjustment of the South Channel unde

关键词： channel-shoal pattern morphological evolution process-based modeling South Channel Changjiang Estuary

Thrust and Swimming Speed Analysis of Fish Robot with Non-uniform Flexible Tail

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Journal of Bionic Engineering 2016年第1期13卷 73-83页

作者： Phi luan Nguyen Byung Ryong Lee Kyoung Kwan Ahn School of Mechanical Engineering University of Ulsan Ulsan Korea

We present a dynamic model of a fish robot with a Non-uniform Flexible Tail （NFT）. We investigate the tendencies of the thrust and swimming speed when the input driving moment changes. Based on the proposed dynamic model of the NFT, we derive the thrust estimation, equation of motion, and performance evaluation of a fish robot with a NFT. By defining the optimal stiffness of the NFT in simulation, a fish robot prototype is then designed and fabricated. A series of experiments are performed to verify the proposed model. Experiment results are in good agreement with simulation data. The results show that the thrust and swimming speed of the fish robot are proportional to the amplitude of the driving moment. There are two resonant fre- quencies （f = 1.4 Hz and 2.2 Hz）, the maximum thrust and swimming speed （about 0.7 BL.s-1） are found to be around f = 1.4 Hz. The above results inidicate the proposed model is suitable for predicting the behavior, thrust and swimming speed of a fish robot with a NFT.

关键词： fish robot flexible tail dynamic modeling swimming speed thrust Froude efficiency

Morphology and multifractal features of a guyot in specific topographic vicinity in the Caroline Ridge,West Pacific

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Journal of Oceanology and Limnology 2021年第5期39卷 1591-1604页

作者： Yu GAN Xiaochuan MA Zhendong luan Jun YAN CAS Key Laboratory of Marine Geology and Environment Institute ofOceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Geology Pilot National Laboratory for MarineScience and Technology(Qingdao)Qingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao266071China

Massive seamounts have been surveyed and documented in the last ***,the morphologies of seamounts are usually described in qualitative manners,yet few quantitative detections have been carried ***,based on the high-re solution multi-beam bathymetric data,we report a recentlysurveyed guy ot on the Caroline Ridge in the West Pacific,and the large-scale volcanic structures and smallscale erosive-depositional landforms in the guyot area have been *** multifractal features of the guyot are characterized for the first time by applying multifractal detrended fluctuation analysis on the surveyed bathymetric *** results indicate that the multifractal spectrum parameters of the seafloor have strong spatial dependency on the fluctuations of local *** small-and large-scale components contribute to the degree of asymmetry of the multifractal spectrum(B),while the fluctuations of B are mostly attributed to the changes in small-scale *** maximum singularity strength(α0)correlates well with the roughness of large-scale landforms and likely reflects the large-scale topographic *** to traditional roughness parameters or monofractal exponents,multifractal spectra are able to depict not only the multiscale characteristics of submarine landforms,but also the spatial variations of scaling *** more comparative works are required for various seamounts,we hope this study,as a case of quantifying geomorphological characters and multiscale behaviors of seamounts,can encourage further studies on seamounts concerning geomorphological processes,ocean bottom circulations,and seamount ecosystems.

关键词： guyot morphology multifractal detrended fluctuation analysis(MFDFA) Caroline Ridge West Pacific Ocean

New insights into the transovarial transmission of the symbiont Rickettsia in whiteflies

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Science China(Life Sciences) 2021年第7期64卷 1174-1186页

作者： Hongwei Shan Yinquan Liu Junbo luan Shusheng Liu Ministry ofAgriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects Institute ofInsect SciencesZhejiang UniversityHangzhou 310058China College of Plant Protection Shenyang Agricultural UniversityShenyang 110866China

Endosymbiont transmission via eggs to future host generations has been recognized as the main strategy for its persistence in insect hosts;however,the mechanisms for transmission have yet to be ***,we describe the dynamic locations of Rickettsia in the ovarioles and eggs during oogenesis and embryogenesis in a globally significant pest whitefly Bemisia *** populations of the whitefly have a high prevalence of Rickettsia,and in all Rickettsia-infected individuals,the bacterium distributes in the body cavity of the host,especially in the midgut,fat body,hemocytes,hemolymph,and near *** distribution of Rickettsia was subjected to dynamic changes in the ovary during oogenesis,and our ultrastructural observations indicated that the bacteria infect host ovarioles during early developmental stages via two routes:(i)invasion of the tropharium by endocytosis and then transmission into vitellarium via nutritive cord and(ii)entry into vitellarium by hijacking bacteriocyte *** of the Rickettsia are degraded in the oocyte cytoplasm in late-stage ***,a few reside beneath the vitelline envelope of mature eggs,spread into the embryo,and proliferate during embryogenesis to sustain high-fidelity transmission to the next *** findings provide novel insights into the maternal transmission underpinning the persistence and spread of insect symbionts.

关键词： Bemisia tabaci Rickettsia symbiosis vertical transmission

Dynamic Modeling of a Non-Uniform Flexible Tail for a Robotic Fish

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Journal of Bionic Engineering 2013年第2期10卷 201-209页

作者： Phi luan Nguyen Van Phu Do Byung Ryong Lee Intelligent Control and Mechatronics Lab School of Mechanical Engineering University of Ulsan Ulsan 680-749 Korea School of Mechanical Engineering University of Ulsan Ulsan 680-749 Korea

In this paper, a non-uniform flexible tail of a fish robot was presented and the dynamic model was developed. In this model, the non-uniform flexible tail was modeled by a rotary slender beam. The hydrodynamics forces, including the reactive force and resistive force, were analyzed in order to derive the governing equation. This equation is a fourth-order in space and second-order in time Partial Differential Equation （PDE） of the lateral movement function. The coefficients of this PDE were not constants because of the non-uniform beams, so they were approximated by exponential functions in order to obtain an analytical solution. This solution describes the lateral movement of the flexible tail as a function of material, geometrical and actuator properties. Experiments were then carried out and compared to simulations. It was proved that the proposed model is suitable for predicting the real behavior of fish robots.

关键词： fish robot flexible tail dynamic modeling kinematic lateral movement

Analysis of Two-Grid Methods for Nonlinear Parabolic Equations by Expanded Mixed Finite Element Methods

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Advances in Applied Mathematics and Mechanics 2009年第6期1卷 830-844页

作者： Yanping Chen Peng luan Zuliang Lu School of Mathematical Science South China Normal UniversityGuangzhou 510631GuangdongChina Mathematics Teaching and Research Group Sanshui Experimental High School of Zhongshan UniversityFoshan 528145GuangdongChina Hunan Key Lab for Computation and Simulation in Science and Engineering Department of MathematicsXiangtan UniversityXiangtan 411105HunanChina

In this paper,we present an efficient method of two-grid scheme for the approximation of two-dimensional nonlinear parabolic equations using an expanded mixed finite element *** use two Newton iterations on the fine grid in our ***,we solve an original nonlinear problem on the coarse nonlinear grid,then we use Newton iterations on the fine grid *** two-grid idea is from Xu's work[SIAM ***.,33(1996),pp.1759–1777]on standard finite *** also obtain the error estimates for the algorithms of the two-grid *** is shown that the algorithm achieve asymptotically optimal approximation rate with the two-grid methods as long as the mesh sizes satisfy h=O(H^((4k+1)/(k+1))).

关键词： Nonlinear parabolic equations two-grid scheme expanded mixed finite element methods Gronwall’s Lemma

Targeting ferroptosis and ferritinophagy:new targets for cardiovascular diseases

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第1期25卷 1-22页

作者： Yi luan Yang YANG Ying luan Hui LIU Han XING Jinyan PEI Hengdao LIU Bo QIN Kaidi REN Clinical Systems Biology Research Laboratories Translational Medicine Centerthe First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China State Key Laboratory for Artificial Microstructures and Mesoscopic Physics School of PhysicsPeking UniversityBeijing100871China School of Laboratory Medicine Xinxiang Medical UniversityXinxiang453003China Quality Management Department Henan No.3 Provincial People’s HospitalZhengzhou450052China Department of Cardiology the First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China Center for Translational Medicine the First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China Department of Pharmacy the First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China Henan Key Laboratory of Precision Clinical Pharmacy Zhengzhou UniversityZhengzhou450052China Henan Engineering Research Center for Application&Translation of Precision Clinical Pharmacy Zhengzhou UniversityZhengzhou450052China

Cardiovascular diseases(CVDs)are a leading factor driving mortality ***,an essential trace mineral,is important in numerous biological processes,and its role in CVDs has raised broad discussion for ***-mediated cell death,namely ferroptosis,has attracted much attention due to its critical role in cardiomyocyte damage and ***,ferritinophagy is the upstream mechanism that induces ferroptosis,and is closely related to *** review aims to delineate the processes and mechanisms of ferroptosis and ferritinophagy,and the regulatory pathways and molecular targets involved in ferritinophagy,and to determine their roles in ***,we discuss the possibility of targeting ferritinophagy-induced ferroptosis modulators for treating ***,this review offers some new insights into the pathology of CVDs and identifies possible therapeutic targets.

关键词： Cardiovascular disease Iron Ferroptosis Ferritinophagy Therapeutic target