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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 most equal, and δ = δ*/h*, where δ*and h*are the Stokes-layer thickness 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 ct 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

cooperative Target Fencing of multiple Vehicles for a General Target with connectivity Preservation and collision Avoidance

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Journal of Systems Science & complexity 2024年第1期37卷 136-151页

作者： PAN Zini chen Ben m Department of mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem for n-dimensional systems and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull formed by the ***,the dynamics of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the communication network and collision avoidance among the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a numerical example.

关键词： multi-agent systems networked systems target fencing

PPAR Signaling Pathway may be an Important Predictor of Breast cancer Response to Neoadjuvant chemotherapy

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PPAR Signaling Pathway may be an Important Predictor of Brea...

Interfacial stress engineering toward enhancement of ferroelectricity in Al doped HfO_(2)thin films

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作者： Y.Z.chen J.Y.Xue c.m.chen B.L.Yang G.Y.Liu Z.Z.Shen Z.m.Shao J.Wu Q.H.Xu F.Wu F.Liu X.Ye X.meng Department of Breast Surgery Fudan University Shanghai Cancer Center Department of Oncology Shanghai Medical CollegeFudan University Department of Oncology Surgery First Affiliated Hospital of Wenzhou Medical College2 Fu Xue Lane Fudan University Shanghai cancer center-Institut mérieux Laboratory Fudan University Shanghai Cancer Center

Purpose Neoadjuvant chemotherapy for advanced breast cancer may improve the radicality for a subset of patients,but others may suffer from severe adverse drug reactions without any *** predict the responses to chemotherapy,we performed a phaseⅡtrial of neoadjuvant chemotherapy using a weekly Pcb regimen[paclitaxel (Taxol) plus carboplatin]for stageⅡ/Ⅲbreast cancer and assessed the correlation between baseline gene expression and the tumor response to treatment. methods A total of 61 patients with stage II-Ⅲbreast cancer were included and administered four cycles of preoperative *** performed a gene expression analysis using Affymetrix HG-U133 Plus 2.0 Genechip arrays in 31 breast cancer *** expressed genes(DEGs) were identified by the Significance Analysis of microarrays(SAm) program using a false discovery rate(FDR) of *** Functional Annotation Tool in the DAVID Bioinformatics Resources was used to perform the gene functional enrichment *** other 30 patients(15 pcR and 15 non-pcR patients) were available as an independent validation set to test the selected DEGs by quantitative real-time PcR analysis(qRT-PcR). Results By analyzing six pathological complete response(pcR) patients and 25 patients with non-pcR,300 probes(231 genes) were identified as differentially expressed between pcR and residual disease by the SAm program when the fold change was>*** gene functional enrichment analysis revealed 15 prominent gene categories that were different between pcR and non-pcR patients,most notably the genes involved in the PPAR(Peroxisome Proliferator Activated Receptor),DNA repair and ER signal pathways and in the immune-related gene *** qRT-PcR analysis results for the genes in the PPAR pathway(LPL,SORBSl,PLTP,ScD5,mmPl and cSTA) in independent validation set were consistent with the results from the microarray data analysis. conclusion In the present study,we identified a number of gene categories pertinent to the ther

关键词： Neoadjuvant Gene expression chemotherapy response PPAR pathway DNA repair

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chinese Physics B 2024年第9期33卷 637-643页

作者： S X chen m m chen Y Liu D W cao G J chen Department of microelectronics Jiangsu UniversityZhenjiang 212013China Department of Physics Jiangsu UniversityZhenjiang 212013China Guangdong–Hong Kong–macao Joint Laboratory for Intelligent micro-Nano Optoelectronic Technology Foshan UniversityFoshan 528225China

Ferroelectric HfO_(2)has attracted much attention owing to its superior ferroelectricity at an ultra-thin thickness and good compatibility with Si-based complementary metal-oxide-semiconductor(cmOS)***,the crystallization of polar orthorhombic phase(o-phase)HfO_(2)is less competitive,which greatly limits the ferroelectricity of the as-obtained ferroelectric HfO_(2)thin ***,the crystallization of o-phase HfO_(2)can be thermodynamically modulated via interfacial stress *** this paper,the growth of improved ferroelectric Al doped HfO_(2)(HfO_(2):Al)thin films on(111)-oriented Si substrate has been *** analysis has suggested that nonpolar monoclinic HfO_(2):Al grown on(111)-oriented Si substrate suffered from a strong compressive strain,which promoted the crystallization of(111)-oriented o-phase HfO_(2)in the as-grown HfO_(2):Al thin *** addition,the in-plane lattice of(111)-oriented Si substrate matches well with that of(111)-oriented o-phase HfO_(2),which further thermally stabilizes the o-phase HfO_(2).Accordingly,an improved ferroelectricity with a remnant polarization(2P_(r))of 26.7c/cm^(2) has been *** results shown in this work provide a simple way toward the preparation of improved ferroelectric HfO_(2)thin films.

关键词： improved ferroelectricity interfacial stress engineering compressive strain HfO_(2)

A hierarchical multi-UAV cooperative framework for infrastructure inspection and reconstruction

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control Theory and Technology 2024年第3期22卷 394-405页

作者： chuanxiang Gao Xinyi Wang Xi chen Ben m.chen Department of mechanical and Automation Engineering The Chinese University of Hong KongHong KongShatinNTChina

Unmanned aerial vehicles(UAVs)are emerging as a powerful tool for inspections and repair works in large-scale and unstructured 3D infrastructures,but current approaches take a long time to cover the entire *** using UAVs for inspections and repair works puts forward a requirement of improving time efficiency in large-scale and cluster *** paper presents a hierarchical multi-UAV cooperative framework for infrastructure inspection and reconstruction to balance the workload and reduce the overall task completion *** proposed framework consists of two stages,the exploration stage and the exploitation stage,resolving the task in a sequential *** the exploration stage,the density map is developed to update global and local information for dynamic load-balanced area partition based on reconstructability and relative positions of UAVs,and the Voronoi-based planner is used to enable the UAVs to reach their best *** obtaining the global map,viewpoints are generated and divided while taking into account the battery capacity of each ***,a shortest path planning method is used to minimize the total traveling cost of these viewpoints for obtaining a high-quality *** experiments are conducted in both a simulated and real environment to show the time efficiency,robustness,and effectiveness of the proposed ***,the whole system is implemented in real applications.

关键词： multi-UAV coverage path planning Infrastructure inspection and reconstruction

Local mFS matrix Decomposition Algorithms for Elliptic BVPs in Annuli

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NUmERIcAL mATHEmATIcS-THEORY mETHODS AND APPLIcATIONS 2024年第1期17卷 93-120页

作者： chen, c. S. Karageorghis, Andreas Lei, min Univ Southern mississippi Sch Math & Nat Sci Hattiesburg MS 39406 USA Univ cyprus Dept Math & Stat POB 20537 CY-1678 Nicosia Cyprus Taiyuan Univ Technol Coll Math Taiyuan 030024 Peoples R China

We apply the local method of fundamental solutions (LmFS) to boundary value problems (BVPs) for the Laplace and homogeneous biharmonic equations in annuli. By appropriately choosing the collocation points, the LmFS discretization yields sparse block circulant system matrices. As a result, matrix decomposition algorithms (mDAs) and fast Fourier transforms (FFTs) can be used for the solution of the systems resulting in considerable savings in both computational time and storage requirements. The accuracy of the method and its ability to solve large scale problems are demonstrated by applying it to several numerical experiments.

关键词： Local method of fundamental solutions Poisson equation biharmonic equation matrix decomposition algorithms fast Fourier transforms BOUNDARY-VALUE-PROBLEmS FUNDAmENTAL-SOLUTIONS RBF ALGORITHmS

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

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

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