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Effects of layer interactions on instantaneous stability of finite Stokes flows

Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 69-84页

作者： chen ZHAO Zhenli chen c.T.MUTASA Dong LI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

The stability analysis of a finite Stokes layer is of practical importance in flow control. In the present work, the instantaneous stability of a finite Stokes layer with layer interactions is studied via a linear stability analysis of the frozen phases of the base flow. The oscillations of two plates can have different velocity amplitudes, initial phases, and frequencies. The effects of the Stokes-layer interactions on the stability when two plates oscillate synchronously are analyzed. The growth rates of two most unstable modes when δ ckness and the half height of the channel, respectively. However, their vorticities are different. The vorticity of the most unstable mode is symmetric, while the other is asymmetric. The Stokes-layer interactions have a destabilizing effect on the most unstable mode when δ g effect when δ > 0.68. However, the interactions always have a stabilizing effect on the other unstable mode. It is explained that one of the two unstable modes has much higher dissipation than the other one when the Stokes-layer interactions are strong. We also find that the stability of the Stokes layer is closely related to the inflectional points of the base-flow velocity profile. The effects of inconsistent velocity-amplitude, initial phase, and frequency of the oscillations on the stability are analyzed. The energy of the most unstable eigenvector is mainly distributed near the plate of higher velocity amplitude or higher oscillation frequency. The effects of the initial phase difference are complicated because the base-flow velocity is extremely sensitive to the initial phase.

关键词： finite Stokes layer instantaneous stability Stokes-layer interaction asynchronous oscillation

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coupled Inversion of Pressure and Tiltmeter Data for Mapping Hydraulic Fracture geometry

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Acta Mechanica Solida Sinica 2024年第3期37卷 396-405页

作者： Zuorong chen Xiaofang Jiang Zhejun Pan Robert g.Jeffrey National Key Laboratory of continental Shale Oil Northeast Petroleum UniversityDaqing163318China ScT Operation Pty.Ltd. PO Box 824WollongongNSW2520Australia

Pressure and tilt data are jointly inverted to simultaneously map the orientation and dimensions of a hydraulic *** deformation induced by a fracture under internal pressure is modeled using the distributed dislocation *** planar fracture is represented by four quarter ellipses,joined at the center and sharing *** configuration provides a straightforward model for characterizing asymmetric fracture *** inverse problem of mapping the fracture geometry is formulated using the Bayesian probabilistic method,combining the a priori information on the fracture model with updated information from pressure and tilt *** the nonlinear inverse problem is achieved by pseudo-randomly sampling the posterior probability distribution through the Markov chain Monte carlo *** resulting posterior probability distribution is then explored to assess uncertainty,resolution,and correlation between model *** experiments are conducted to verify the accuracy and validity of the proposed analysis method in mapping the fracture geometry using synthetic pressure and tilt data.

关键词： Hydraulic fracture mapping coupled inversion Tilt Treating pressure

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Dynamic Event-Triggered consensus control for Input constrained Multi-Agent Systems With a Designable Minimum Inter-Event Time

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IEEE/cAA Journal of Automatica Sinica 2024年第3期11卷 649-660页

作者： Meilin Li Yue Long Tieshan Li Hongjing Liang c.L.Philip chen the School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731China IEEE the Yangtze Delta Region Institute University of Electronic Science and Technology of ChinaHuzhou 313000 the Laboratory of Electromagnetic Space cognition and Intelligent control Beijing 100089China the School of computer Science and Engineering South China University of TechnologyGuangzhou 510006

This paper investigates the consensus control of multi-agent systems(MASs) with constrained input using the dynamic event-triggered mechanism(ETM).consider the MASs with small-scale networks where a centralized dynamic ETM with global information of the MASs is first ***,a distributed dynamic ETM which only uses local information is developed for the MASs with large-scale *** is shown that the semi-global consensus of the MASs can be achieved by the designed bounded control protocol where the Zeno phenomenon is eliminated by a designable minimum inter-event *** addition,it is easier to find a trade-off between the convergence rate and the minimum inter-event time by an adjustable ***,the results are extended to regional consensus of the MASs with the bounded control *** simulations show the effectiveness of the proposed approach.

关键词： constrained input designable minimum inter-event time directed communication topology dynamic event-triggered mechanism MASs consensus control

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Barosinusitis due to routine weather changes:A cross-sectional analysis of public websites

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World Journal of Otorhinolaryngology-Head and Neck Surgery 2024年第1期10卷 18-23页

作者： James c.campbell Julia E.canick Philip g.chen Ralph Abi Hachem David W.Jang Department of Head and Neck Surgery&communication Sciences Duke University School of MedicineDurhamNorth CarolinaUSA Duke University School of Medicine DurhamNorth CarolinaUSA Department of Otolaryngology-Head and Neck Surgery University of Texas Health Science Center San AntonioSan AntonioTexasUSA

Background:Sinusitis is a common diagnosis that can be erroneously associated with routine weather‐related barometric pressure *** actuality,these pressure changes likely exacerbate migraine headaches,which can cause facial pain and pressure rather than true sinus ***:The present study sought to characterize the representation of both sinusitis and migraine in association with barometric pressure changes across websites on the ***:An Internet search for relevant terms was conducted,and content of the resulting pages was assessed for associations between weather‐related pressure changes and either sinusitis or *** in reported results across different subtypes of Internet sources were *** primary outcomes measured were(1)whether a given media source associated barometric weather changes with sinusitis,(2)whether that source associated barometric weather changes with migraine,and(3)treatment options offered by that ***:Of the 116 included webpages,36(31.03%)associated sinusitis and routine barometric pressure *** these,10(27.77%)were otolaryngology practice ***‐seven webpages(57.76%)associated migraine and routine barometric pressure *** these,nonotolaryngology webpages were more likely to report this ***:Otolaryngology practice sites were observed to be the most frequent professional medical resource reporting the unsubstantiated claim that routine barometric pressure changes are associated with *** sources were more likely to link weather‐related pressure changes to *** results suggest that opportunities exist for otolaryngology practice sites to educate patients about nonrhinogenic headache etiologies.

关键词： acute rhinosinusitis balloon sinus dilation headache migraine sinusitis

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Adaptive neural network control of a 2-DOF helicopter system considering input constraints and global prescribed performance

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Science china(Information Sciences) 2024年第7期67卷 224-239页

作者： Zhijia ZHAO Jiale WU Zhijie LIU We HE c.L.Philip chen School of Mechanical and Electrical Engineering Guangzhou University School of Intelligence Science and Technology and Key Laboratory of Intelligent Bionic Unmanned Systems of Ministry of Education University of Science and Technology Beijing School of computer Science and Engineering South China University of Technology Pazhou Lab

In this study, an adaptive neural network(NN) control is proposed for nonlinear two-degree-offreedom(2-DOF) helicopter systems considering the input constraints and global prescribed ***, radial basis function NN(RBFNN) is employed to estimate the unknown dynamics of the helicopter system. Second, a smooth nonaffine function is exploited to approximate and address nonlinear constraint functions. Subsequently, a new prescribed function is proposed, and an original constrained error is transformed into an equivalent unconstrained error using the error transformation and barrier function transformation methods. The analysis of the established Lyapunov function proves that the controlled system is globally uniformly bounded. Finally, the simulation and experimental results on a constructed Quanser's test platform verify the rationality and feasibility of the proposed control.

关键词： adaptive NN control 2-DOF helicopter global prescribed performance input constraints

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Mechanistic insight into cr(Ⅵ)retention by Si-containing ferrihydrite

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Journal of Environmental Sciences 2024年第5期139卷 217-225页

作者： Ying Hu Qiang Xue Honghan chen Huaming guo Kenneth c.carroll Song Wang MOE Key Laboratory of groundwater circulation and Environmental Evolution School of Water Resources and EnvironmentChina University of Geosciences(Beijing)Beijing 100083China Beijing Key Laboratory of Water Resources and Environmental Engineering School of Water Resources and EnvironmentChina University of GeosciencesBeijing 100083China State Key Laboratory of Biogeology and Environmental geology China University of GeosciencesBeijing 100083China Plant&Environmental Science New Mexico State UniversityNM 88003USA Institute of Theoretical chemistry College of ChemistryJilin UniversityChangchun 130023China

Hexavalent chromium[cr(Ⅵ)]causes serious harm to the environment due to its high toxicity,solubility,and ***(Fh)are the main adsorbent and trapping agent of cr(Ⅵ)in soils and aquifers,and they usually coexist with silicate(Si),forming Si-containing ferrihydrite(Si-Fh)***,the mechanism of cr(Ⅵ)retention by Si-Fh mixtures is poorly *** this study,the behaviors and mechanisms of cr(Ⅵ)adsorption onto Si-Fh with different Si/Fe molar ratios was *** electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and other techniques were used to characterize Si-Fh and cr(Ⅵ)-loading of *** results show that specific surface area of Si-Fh increases gradually with increasing Si/Fe ratios,but cr(Ⅵ)adsorption on Si-Fh decreases with increasing Si/Fe *** is because with an increase in Si/Fe molar ratio,the point of zero charge of Si-Fh gradually decreases and electrostatic repulsion between Si-Fh and cr(Ⅵ)***,the complexation of cr(Ⅵ)is enhanced due to the increase in adsorbed hydroxyl(A-OH-)on Si-Fh with increasing Si/Fe molar ratio,which partly counteracts the effect of the electrostatic ***,the increase in the electrostatic repulsion has a greater impact on adsorption than the additional complexation with *** functional theory calculation further supports this observation,showing the increases in electron variation of bonding atoms and reaction energies of inner spherical complexes with the increase in Si/Fe ratio.

关键词： Hexavalent chromium Ferrihydrite Si/Fe ratio cr(Ⅵ)Adsorption

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construction of a novel six-gene signature to predict tumour response to induction chemotherapy and overall survival in locoregionally advanced laryngeal and hypopharyngeal carcinoma

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genes & Diseases 2024年第3期11卷 148-150页

作者： chen Tan Lingwa Wang Yifan Yang Shizhi He george g.chen Jason YK.chan Michael cF.Tong c.A.van Hasselt Wenbin Xu Ling Feng Ru Wang Jugao Fang Department of Otolaryngology Head and Neck Surgery Beijing Tongren HospitalCapital Medical UniversityBeijing 100730China Key Laboratory of Otolaryngology Head and Neck Surgery(Ministry of Education of china) Beijing Institute of OtolaryngologyBeijing 100730China Department of Otorhinolaryngology Head and Neck SurgeryThe Chinese University of Hong KongPrince of Wales HospitalHongKong SAR999077China Department of Medical genetics Institute of Basic Medical ScienceChinese Academy of Medical Science&Peking Union Medical CollageBeijing 100730China

Locoregionally advanced laryngeal and hypopharyngeal cancers(LA-LHcs)are traditionally treated with surgery followed by postoperative radiotherapy,which impairs speech and swallowing functions and reduces the quality of life.^(1,2)The use of induction chemotherapy(Ic)as a larynxpreserving approach for LA-LHcs has been verified and refined.^(3)However,the short-term tumor response to Ic varies,non-responders usually show poor survival and little benefit.

关键词： chemotherapy laryngeal surgery

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Liquefaction susceptibility and deformation characteristics of saturated coral sandy soils subjected to cyclic loadings-a critical review

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 261-296页

作者： chen guoxing Qin You Ma Weijia Liang Ke Wu Qi c.Hsein Juang Institute of geotechnical Engineering Nanjing Tech UniversityNanjing 210009China civil Engineering and Earthquake Disaster Prevention center of Jiangsu Province Nanjing 210009China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China college of civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 210016China glenn Department of civil Engineering Clemson UniversityClemsonSC 29634USA

coral sandy soils widely exist in coral island reefs and seashores in tropical and subtropical *** to the unique marine depositional environment of coral sandy soils,the engineering characteristics and responses of these soils subjected to monotonic and cyclic loadings have been a subject of intense interest among the geotechnical and earthquake engineering *** paper critically reviews the progress of experimental investigations on the undrained behavior of coral sandy soils under monotonic and cyclic loadings over the last three *** focus of coverage includes the contractive-dilative behavior,the pattern of excess pore-water pressure(EPWP)generation and the liquefaction mechanism and liquefaction resistance,the small-strain shear modulus and strain-dependent shear modulus and damping,the cyclic softening feature,and the anisotropic characteristics of undrained responses of saturated coral sandy *** particular,the advances made in the past decades are reviewed from the following aspects:(1)the characterization of factors that impact the mechanism and patterns of EPWP build-up;(2)the identification of liquefaction triggering in terms of the apparent viscosity and the average flow coefficient;(3)the establishment of the invariable form of strain-based,stress-based,or energy-based EPWP ratio formulas and the unique relationship between the new proxy of liquefaction resistance and the number of cycles required to reach liquefaction;(4)the establishment of the invariable form of the predictive formulas of small strain modulus and strain-dependent shear modulus;and(5)the investigation on the effects of stress-induced anisotropy on liquefaction susceptibility and dynamic deformation *** gained through the critical review of these advances in the past decades offer a perspective for future research to further resolve the fundamental issues concerning the liquefaction mechanism and responses of coral sandy sites subjecte

关键词： liquefaction susceptibility dynamic deformation characteristics coral sandy soil cyclic loading review and prospect

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The anti-inflammatory effects of exercise on autoimmune diseases:A 20-year systematic review

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Journal of Sport and Health Science 2024年第3期13卷 353-367,I0001页

作者： Beibei Luo Dao Xiang Xiaorong Ji Xuan chen Rui Li Shuxin Zhang Yujun Meng David c.Nieman Peijie chen School of Exercise and Health Shanghai University of SportShanghai 200438China Shanghai Key Laboratory of Human Performance Shanghai University of SportShanghai 200438China Department of Diving and Hyperbaric Medicine Naval Medical CenterShanghai 200433China National Key Laboratory of Immunity and Inflammation Naval Medical UniversityShanghai 200433China Human Performance Laboratory Appalachian State UniversityNorth Carolina Research CampusKannapolisNC 28081USA Research Institute for Doping control Shanghai University of SportShanghai 200438China

Background:The anti-inflammatory effect of exercise may be an underlying factor in improving several autoimmune *** aim of this systematic review was to examine the evidence on the role of exercise training in mitigating inflammation in adolescents and adults with autoimmune ***:PubMed,Web of Science,and Embase databases were systematically reviewed for related studies published between January 1,2003,and August 31,*** randomized and non-randomized controlled trials of exercise interventions with autoimmune disease study participants that evaluated inflammation-related biomarkers were *** quality of evidence was assessed using the Tool for the assEssment of Study qualiTy and reporting in EXercise scale and cochrane bias risk ***:A total of 14,565 records were *** screening the titles,abstracts,and full texts,87 were eligible for the systematic *** studies were conducted in 25 different countries and included a total of 2779 participants(patients with autoimmune disease,in exercise or control groups).Overall,the evidence suggests that inflammation-related markers such as c-reactive protein,interleukin 6,and tumor necrosis factor a were reduced by regular exercise *** exercise interventions combined with multiple exercise modes were associated with greater ***:Regular exercise training by patients with autoimmune disease exerts an anti-inflammatory *** systematic review provides support for the promotion and development of clinical exercise intervention programs for patients with autoimmune *** patients with autoimmune disease can safely adopt moderate exercise training protocols,but changes in inflammation biomarkers will be modest at *** exercise interventions are ineffective or even modestly but transiently pro-inflammatory.

关键词： Autoimmune diseases cytokines Inflammation Physical activity Training

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Meridional deflection of global eddy propagation derived from tandem altimetry: Mechanism and implication

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Science china Earth Sciences 2024年第3期67卷 811-825页

作者： ge chen Xiaoyan chen Frontiers Science center for Deep Ocean Multispheres and Earth System School of Marine TechnologyOcean University of ChinaQindao 266100China Laboratory for Regional Oceanography and Numerical Modeling Laoshan LaboratoryQindao 266237China

A common view on meridional deflection of eddy propagation is poleward for cyclones and equatorward for anticyclones. This widely accepted polarity-sensitive pattern has been increasingly undermined given that it is systematically violated on both zonal and regional scales as recently reported. Here, we approach the problem by exploring these violations in terms of eddy effects of spatiotemporal geostrophy, thermal fading, and flow dragging, yielding the following main conclusions.(1) The polarity-dependent deflection discrepancy is a pseudo feature resulting from a biased fit to the normalized eddy tracks which are spatially asymmetric(though azimuthally symmetric) between the two signs;Instead, the primary pattern of eddy deflection appears to be geographically correlated and polarity independent.(2) geostrophic adjustment plays a critical role in defining the meridional movement of an eddy. Specifically, a consistent poleward(equatorward) trajectory bending of spatially(temporally) ageostrophic eddies is observed irrespective of their polarity.(3) The mechanism of eddy deflection is also determined by its zonal propagation direction. Westward propagating eddies are substantially affected by thermal fading, while opposite ones by flow dragging. A realistic and comprehensive understanding of eddy deflection mechanisms serves as a significant contribution to the prediction of eddy trajectory, and the protection of ocean environment.

关键词： Mesoscale eddies Eddy propagation Eddy meridional deflection Satellite observation geostrophic adjustment

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