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Matched Volterra reduced-order model for an airfoil undergoing periodic translation

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Chinese Journal of Aeronautics 2024年第1期37卷 19-23页

作者： Lianrui nie Ziniu WU Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China

This paper is devoted to application of the Reduced-Order Model(ROM)based on Volterra series to prediction of lift and drag forces due to airfoil periodic translation in transonic flow *** there is large amplitude oscillation of the relative Mach number,as appeared in helicopter rotor movement in forward flight,the conventional Volterra ROM is found to be *** cover such applications,a matched Volterra ROM,inspired from previous multistep nonlinear indicial response method based on Duhamel integration,is thus considered,in which the step motions are defined inside a number of equal intervals with both positive and negative step motions to match the airfoil forward and backward movement,and the kernel functions are constructed independently at each *** shows that,at least for the translation movement considered,this matched Volterra ROM greatly improves the accuracy of ***,the matched Volterra ROM,with the total number of step motions and thus the computational cost close to those of the conventional Volterra ROM method,has the additional advantage that the same set of kernels can match various translation motions with different starting conditions so the kernels can be predesigned without knowing the specific motion of airfoil.

关键词： Airfoil periodic translation Lift and drag Reduced-order model Transonic flow Unsteady flow

Collectively induced transparency and absorption in waveguide quantum electrodynamics with Bragg atom arrays

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Communications in Theoretical Physics 2024年第8期76卷 21-30页

作者： Haolei Cheng Wei nie Center for Joint Quantum Studies and Department of Physics School of Science Tianjin University Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology Tianjin University

Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous *** atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption(CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide quantum electrodynamics(QED) systems.

关键词： Bragg atom array collective quantum states photon absorption waveguide quantum electrodynamics

The direct electrochemistry of glucose oxidase based on the synergic effect of amino acid ionic liquid and carbon nanotubes

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Science China Chemistry 2009年第11期52卷 1991-1998,2033-2034页

作者： WANG MengDong DENG ChunYan nie zhou XU XiaHong YAO ShouZhuo State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China

Amino acid ionic liquids(AAILs) have attracted much attention due to their special chemical and physical properties,especially their outstanding biocompatibility and truly green *** this work,a novel electrochemical biosensing platform based on AAILs/carbon nanotubes(CNTs) composite was *** were used as a novel solvent for glucose oxidase(GOD) and the GOD-AAILs/CNTs/GC electrode was conveniently prepared by immersing the carbon nanotubes(CNTs) modified glassy carbon(GC) electrode into AAILs containing *** direct electrochemistry of GOD on the GOD-AAILs/CNTs/GC electrode has been investigated and a pair of reversible peaks was obtained by cyclic *** immobilized glucose oxidase could retain bioactivity and catalyze the reduction of dissolved *** to the synergic effect of AAILs and CNTs,the GOD-AAILs/CNTs/GC electrode shows excellent electrocatalytic activity towards glucose with a linear range from 0.05 to 0.8 mM and a detection limit of 5.5 μM(S/N = 3).Furthermore,the biosensor exhibits good stability and ability to exclude the interference of commonly coexisting uric and ascorbic ***,AAILs/CNTs composite can be a good candidate biocompatible material for the direct electrochemistry of the redox-active enzyme and the construction of third-generation enzyme sensors.

关键词： amino acid ionic liquids(AAILs) carbon nanotubes(CNTs) glucose oxidase(GOD) direct electrochemistry glucose sensor

Facile and effective synthesis strategy for terbium-doped hydroxyapatite toward photoelectric devices and flexible functional fibers

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Rare Metals 2024年第4期43卷 1713-1723页

作者： Xiao-Dong Zhang Kun nie Zi-Yao Hu Ran-Ran zhou Xiu-Qiang Duan Wu-Bin Dai Song-Song nie Song-Jun Yao Luo-Xin Wang Le-Fu Mei Hua Wang Yi-Yi Yao Xiao-Xue Ma Hubei Key Laboratory for New Textile Materials and Applications and State Key Laboratory of New Textile Materials and Advanced Processing Technology School of Materials Science and EngineeringWuhan Textile UniversityWuhan430200China Key Laboratory of Testing and Tracing of Rare Earth Products for State Market Regulation Jiangxi University of Science and TechnologyGanzhou341000China Hubei Key Laboratory of Plasma Chemistry and Advanced Materials and Key Laboratory of Green Chemical Engineering Process of Ministry of Education Wuhan Institute of TechnologyWuhan430205China

As a material with good biocompatibility,hydroxyapatite(HAP)can have optical properties after doping with various rare earth *** a biocompatible fluorescent material,doped HAP could have broad applications in biological probes,drug delivery,optoelectronic materials,fluorescence anti-counterfeiting,and other *** this paper,we put forward the preparation of HAP doped with terbium(Ⅲ)ions(Tb^(3+))by hydrothermal *** controlling the Tb^(3+)doping content in reaction and the reaction time,the changes in HAP's structure,morphology,and luminescence properties under different conditions were *** the doping amount of Tb^(3+)reached an optimal value,the dipole-quadrupole would occur and the concentration would be *** control experiment showed that the optimal Tb3+content was 7.5×10^(-5)mol,which showed the best fluorescence ***,a non-luminous material,was rarely used in the field of fluorescent anti-counterfeiting and photoelectric *** proposed to prepare a luminescent aramid/polyphenylene sulfide(ACFs/PPS)fiber paper and a new light-emitting diode(LED)using the Tb-doped HAP *** composite sample exhibited an excellent stability and fluorescence performance,which also demonstrated a possibility of HAP applications in anticounterfeiting and *** introduction of Tb3+dopant HAP was done to give HAP optical properties and broaden the application range of HAP.

关键词： Hydroxyapatite Rare earth luminescence Photoelectric device Aramid Polyphenylene sulfide fiber paper Luminescent fiber

长宁地区低阻页岩孔隙结构精细表征及分形研究

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非常规油气 2024年第1期11卷 45-55页

作者：聂舟陈瑞华姜振学薛子鑫刘达东梁志凯郭婕韩云浩四川长宁天然气开发有限责任公司成都610000 油气资源与探测国家重点实验室北京102249 中国石油大学(北京)非常规油气科学技术研究院北京102249

为明确四川盆地长宁地区龙马溪组低电阻页岩储层孔隙发育差异性,采用低阻页岩与常规页岩相对比的研究手段,开展了有机碳分析、氮气吸附实验、XRD矿物组分分析和扫描电镜等一系列实验,阐明了长宁低阻页岩储层孔隙结构及其分形特征,并明... 详细信息

为明确四川盆地长宁地区龙马溪组低电阻页岩储层孔隙发育差异性,采用低阻页岩与常规页岩相对比的研究手段,开展了有机碳分析、氮气吸附实验、XRD矿物组分分析和扫描电镜等一系列实验,阐明了长宁低阻页岩储层孔隙结构及其分形特征,并明确了它们的控制因素。结果显示,长宁地区大多数低阻页岩孔隙发育程度明显差于常规页岩,其中,孔体积发育的差异主要体现在2~20 nm孔径范围内,比表面积差异则主要集中在小于1.5 nm和大于1.8 nm段。页岩储层孔隙结构随电阻率的降低有变差的趋势,对低电阻页岩储集能力影响更明显的是有机质含量和成熟度。相较于常规电阻页岩,低电阻页岩在小孔隙段具有更加复杂的孔径及孔壁发育。黏土矿物和黄铁矿对分形维数的影响在不同电阻率页岩中是一致的,而有机质对2类页岩分形维数的影响相反。有机质对分形维数的影响与过演化页岩石墨化后的有机孔变化密切相关。

关键词：低阻页岩储层孔隙结构氮气吸附分形维数相关性分析

A Tri-mode of Mock-Walker Cells

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Advances in Atmospheric Sciences 2024年第4期41卷 671-679页

作者： Han QIN Ji nie Zhiyong MENG Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100871China China Meteorological Administration Tornado Key Laboratory Foshan 528061China

This work uses cloud-resolving simulations to study mock-Walker cells driven by a specified sea surface temperature(SST).The associated precipitation in the mock-Walker cells exhibits three different modes,including a single peak of precipitation over the SST maximum(mode 1),symmetric double peaks of precipitation straddling the SST maximum(mode 2),and a single peak of precipitation on one side of the SST maximum(mode 3).The three modes are caused by three distinct convective activity center migration *** indicate that the virtual effect of water vapor plays an important role in differentiating the three *** the SST gradient is large,the virtual effect may be strong enough to overcome the temperature effect,generating a low-level low-pressure anomaly below the ascending branch of the Walker cell off the *** results here highlight the importance of the virtual effect of water vapor and its interaction with convection and large-scale circulation in the Walker circulation.

关键词： Walker circulation cloud-resolving simulation virtual effect

Operational optimization of copper flotation process based on the weighted Gaussian process regression and index-oriented adaptive differential evolution algorithm

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Chinese Journal of Chemical Engineering 2024年第2期66卷 167-179页

作者： Zhiqiang Wang Dakuo He Haotian nie College of Information Science and Engineering Northeastern UniversityShenyang 110004China State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110004China

Concentrate copper grade(CCG)is one of the important production indicators of copper flotation processes,and keeping the CCG at the set value is of great significance to the economic benefit of copper flotation industrial *** paper addresses the fluctuation problem of CCG through an operational optimization ***,a density-based affinity propagationalgorithm is proposed so that more ideal working condition categories can be obtained for the complex raw ore ***,a Bayesian network(BN)is applied to explore the relationship between the operational variables and the *** on the analysis results of BN,a weighted Gaussian process regression model is constructed to predict the CCG that a higher prediction accuracy can be *** ensure the predicted CCG is close to the set value with a smaller magnitude of the operation adjustments and a smaller uncertainty of the prediction results,an index-oriented adaptive differential evolution(IOADE)algorithm is proposed,and the convergence performance of IOADE is superior to the traditional differential evolution and adaptive differential evolution ***,the effectiveness and feasibility of the proposed methods are verified by the experiments on a copper flotation industrial process.

关键词： Weighted Gaussian process regression Index-oriented adaptive differential evolution Operational optimization Copper flotation process

Effect of boundary conditions on shakedown analysis of heterogeneous materials

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 39-68页

作者： Xiuchen GONG Yinghao nie Gengdong CHENG Kai LI State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentInternational Research Center for Computational MechanicsDepartment of Engineering MechanicsDalian University of TechnologyDalian 116023Liaoning ProvinceChina

The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under ***, utilizing PBCs to

关键词： heterogeneous material self-equilibrium stress field(SSF) shakedown analysis effect of boundary conditions

Fluid-structure interaction simulation for multi-body flexible morphing structures

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Chinese Journal of Aeronautics 2024年第2期37卷 137-147页

作者： Wenzhi GUO Yongtao SHUI Lu nie Gang CHEN State Key Laboratory of Strength and Vibration for Mechanic Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China China Academy of Launch Vehicle Technology Beijing 100076China China Academy of Aerospace Science and Innovation Beijing 100086China Shannxi Key Laboratory of Service Environment and Control for Flight Vehicles Xi’an Jiaotong UniversityXi’an 710049China

The multi-body flexible morphing airfoil can improve the aerodynamic characteristics based on different flight missions *** researches have focused on the unsteady aerodynamic characteristics of flexible wings under passive ***,the unsteady aerodynamic characteristics with the fluid-structure interaction effects in the multi-body active actuation process of morphing airfoil deserve further *** this paper,a fluid-structure coupled simulation method for multi-body flexible morphing airfoil with active actuation subsystem was investigated,and the aerodynamic characteristics during deformation were compared with different skin flexibility,flow field environment,actuation mode and actuation *** numerical results show that for the steady aerodynamic,the skin flexibility can improve the stability *** the unsteady process,the change trend of the transient lift coefficient and pitching moment are consistent with those of the active drive characteristics,while the instantaneous lift-drag ratio coefficient is greatly affected by the driving mode and can be improved by increasing the driving duration.

关键词： Fluid-structure interaction Multi-body dynamics modeling Flexible structures Aerodynamics Morphing wings