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Zeros of th. Eta and Zeta Functions

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Journal of Applied Math.matics and Ph.sics 2025年第1期13卷 256-266页

作者： Joh. h. h.inbockel Independent Research.r Virginia Beach Virginia USA

Th. eta function is examined over th. critical strip 0σ1and th.re is an investigation of th. statement th.t all zeros of th. zeta function must lie on th. critical line Re(s)=1/2. A furth.r investigation is made into... 详细信息

关键词： Riemann h.poth.sis Zeta Function Zeros Dirich.et Eta Function Zeros

Continuously adjustable mech.nical metamaterial based on planetary gear trains and external mesh.ng gears

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Applied Math.matics and Mech.nics(English.Edition) 2025年第2期46卷 233-252页

作者： Sh.ai MO Xu TANG Keren Ch.N h. h.UJOh.Wei Zh.NG State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures School of Mechanical Engineering Guangxi University State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South University State Key Laboratory of Digital Manufacturing Equipment and Tech.ology Huazhong University of Science and Technology Precision and Intelligence Laboratory Tokyo Institute of Technology

Th. metamaterial based on external mesh.ng gears(MEG) is designed based on th. principle of external mesh.ng gear transmission. Based on th. mesh.ng transmission principle of external mesh.ng gears and planetary gear trains, th. internal and external gear rings are designed. Based on th. internal and external gear rings, th. metamaterial based on inner and outer planetary gear trains(MIP) is designed to study th. sh.ar modulus, Young's modulus, and amplitude-frequency ch.racteristics of th. metamaterial based on gears at different angles. Th. effects of th. number of planetary gears on th. ph.sical ch.racteristics of th. MIP are studied. Th. results sh.w th.t th. MEG can be continuously adjusted by adjusting th. sh.ar modulus and Young's modulus due to its mesh.ng ch.racteristics. With.th. same number of gears, th. adjustment range of th. MIP is larger th.n th. adjustment range of th. MEG. Wh.n th. number of planetary gears increases, th. adjustment range of th. MIP decreases. Moreover, wh.n th. metamaterial based on gears rotates, th. h.rmonic response ch.nges with.th. ch.nge of th. angle.

关键词： metamaterial adjustable external inner and outer planetary gear train TB34

Estimating Transient Stability Regions of Large-Scale Power Systems Part I: Koopman Operator and Reduced-Order Model

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CSEE Journal of Power and Energy Systems 2025年第1期11卷 24-37页

作者： Yuqing Lin Tianh.o Wen Lei Ch.n Q. h. Wu Yang Liu Sch.ol of Electric Power Engineering South China University of Technology Guangzhou China

Th.s paper presents an estimation of transient stability regions for large-scale power systems. In Part I, a Koopman operator based model reduction (KOMR) meth.d is proposed to derive a low-order dynamical model with.reasonable accuracy for transient stability analysis of large-scale power systems. Unlike traditional reduction meth.ds based on linearized models, th. proposed meth.d does not require linearization, but captures dominant modes of th. original nonlinear dynamics by employing a Koopman operator defined in an infinite-dimensional observable space. Combined with.th. Galerkin projection, th. obtained dominant Koopman eigenvalues and modes produce a reduced-order nonlinear model. To approximate th. Koopman operator with.sufficient accuracy, we introduce a Polynomial-based Multi-trajectory Kernel Dynamic Mode Decomposition (PMK-DMD) algorith., wh.ch.outperforms traditional DMD in various scenarios. In th. end, th. proposed meth.d is applied to th. IEEE 10-mach.ne-39-bus power system and IEEE 16-mach.ne-68-bus power system, wh.ch.demonstrates th.t our meth.d is significantly superior to th. modal analysis meth.d in both.qualitative and quantitative aspects.

关键词： Power system stability Reduced order systems Nonlinear dynamical systems Eigenvalues and eigenfunctions Power system dynamics Kernel Transient analysis Analytical models Accuracy Modal analysis

Estimating Transient Stability Regions of Large-scale Power Systems Part Ⅱ: Reduced-order Stability Region with.Computational Efficiency

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CSEE Journal of Power and Energy Systems 2025年第1期11卷 38-50页

作者： Yuqing Lin Tianh.o Wen Lei Ch.n Yang Liu Q. h. Wu Sch.ol of Electric Power Engineering South China University of TechnologyGuangzhou510640China

Part Ⅱ of th.s paper presents a reduced-order stability region (ROSR) based meth.d to estimate th. full-order stability region (FOSR) of a large-scale power system. First, we introduce th. definitions of FOSR and ROSR, followed by a compreh.nsive th.ory th.t reveals th. relationsh.ps between th.m. Since th. full-order system can be rewritten as a standard two timescale model and th. reduced-order system is regarded as th. slow subsystem of it, th. proposed th.ory is derived based on th. idea of singular perturbation. With.rigorous math.matical proof, th. properties of FOSR and ROSR are revealed. Moreover, a modified Energy Augmented Dynamic (EAD) algorith. and a constrained equidistant projection (CEP) approach.are employed to estimate th. ROSR and FOSR, respectively. Th. modified EAD algorith. and CEP form a so-called reduced-order stability region mapping (ROSRM) meth.d. Finally, th. proposed ROSRM meth.d is applied to th. IEEE 10-mach.ne-39-bus power system, and simulation studies confirm its superiority to th. traditional energy function meth.d in terms of computational speed and reliability of results.

关键词： Large-scale power system singular perturbation th.ory stability region sum of squares transient stability

Dynamic stress concentration in an infinitely long cylindrical cavity due to a point sph.rical source embedded with.n a fluid-saturated poroelastic formation of infinite extent

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Applied Math.matics and Mech.nics(English.Edition) 2025年第1期46卷 139-156页

作者： h.h.SSEINI O.BALILASh.KI Department of Mech.nical Engineering Faculty of EngineeringGolestan University

Th. effects of a h.rmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely with.n a fluid-saturated poroelastic formation of infinite extent are examined th.oretically. It is assumed th.t th. source is located outside th. cavity at a specified distance from th. boreh.le axis. Th. magnitudes of th. h.op and radial stresses beside th. pore pressures exerted on th. interface and inside th. porous medium surrounding th. boreh.le are calculated and discussed. Biot's poroelastic modeling along with.th.ee types of boundary conditions for th. cylindrical interface including th. ideal fluid, empty boreh.le, and rigid inclusion with.a h.rd boundary is employed for th. analysis. Utilizing a proper translational addition th.orem for expressing th. incident sph.rical wave in terms of cylindrical wave expansions, th. proposed boundary conditions at th. interface are satisfied. Stresses are formulated by means of wave potential functions in a th.ee-dimensional(3D) manner. Th. effects of th. frequency and th. radial distance between th. source and boreh.le on th. induced stresses are examined for th. first cylindrical modes over frequency spectra. Two permeability conditions for th. interface and th.ee types of soils for th. porous formation are considered th.ough.ut th. analysis. To give an overall outline of th. study, a numerical example is presented. Th. results clearly indicate th.t th. distance is a key parameter and h.s considerable effects on th. induced stress values. In addition, th. interface permeability condition and soil ch.racteristics play an important role in determining th. dynamic response of th. boreh.le. Finally,th. obtained results are compared with.th. relevant analyses existing in th. literature for some limit cases, and good agreement is ach.eved.

关键词： cylindrical cavity O353.4 point source porous medium stress concentration wave-field transformation

Evaluation of th. Effectiveness of Traditional and Nano Materials Used in Consolidation of Sandstone Used in Ramesses III Temple, Karnak, Egypt

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Journal of Minerals and Materials Ch.racterization and Engineering 2025年第1期13卷 18-30页

作者： Essam h. Moh.med Zeinab Mah.oud Ah.ed Mah.oud L. Abd El-Latif Department of Arch.eological Conservation Faculty of Archaeology South Valley University Qena Egypt Department of Conservation Faculty of Archaeology South Valley University Qena Egypt h.using and Building Research.Center Giza Egypt

Th.s experimental study assesses th. effectiveness of traditional and nano-materials in enh.ncing th. ph.sical and mech.nical properties of deteriorated sandstone from Ramesses III Temple, Karnak, Luxor, Egypt. Treatments included Nano Estel (5%), Paraloid B-72 (3%), Paraloid B-72/Nano Estel (3%/5%), and eth.l silicates. Treated samples underwent Scanning Electron Microscopy (SEM) and ph.sical/mech.nical testing. Results sh.w th.t Paraloid B-72/Nano Estel (3%/5%) yielded optimal consolidation, significantly improving sandstone’s ph.sical and mech.nical properties.

关键词： Ramesses III Temple Deteriorated Sandstone Consolidation Treatments Nano Material Ph.sical and Mech.nical Properties

Multi-Objective optimization for stable and efficient cargo transportation of partial space elevator

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Defence Tech.ology(防务技术) 2025年第2期44卷 17-29页

作者： Gefei Sh. Zh.ng h.Zh. Sch.ol of Aeronautics and Astronautics Sun Yat-sen UniversityGuangzhou 510275China Sh.nzh.n Key Laboratory of Intelligent Microsatellite Constellation Shenzhen 518107China Department of Mech.nical Engineering York University4700 Keele StreetTorontoCanada

Th.s paper proposed a new libration decoupling analytical speed function(LD-ASF)in lieu of th. classic analytical speed function to control th. climber's speed along a partial space elevator to improve libration stability in cargo *** LD-ASF is furth.r optimized for payload transportation efficiency by a novel coordinate game th.ory to balance competing control objectives among payload transport speed,stable end body's libration,and overall control input via model predictive *** transfer period is divided into several sections to reduce computational *** validity and efficacy of th. proposed LD-ASF and coordinate game-based model predictive control are demonstrated by computer *** results reveal th.t th. optimized LD-ASF results in h.gh.r transportation speed,stable end body's libration,lower th.ust fuel consumption,and more flexible optimization space th.n th. classic analytical speed function.

关键词： Partial space elevator Stable transportation Libration decoupling analytical speed function Coordinate game Model predictive control Pareto optimization

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ON Th. GAUSSIAN KINEMATIC FORMULA OF *** AND ***

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Acta Math.matica Scientia 2025年第1期45卷 200-214页

作者： Joseph.h.G.Fu Department of Math.matics University of GeorgiaAthensGA30602USA

We apply meth.ds of algebraic integral geometry to prove a special case of th. Gaussian kinematic formula of *** idea,suggested already by Adler and Taylor,is to view th. GKF as th. limit of sph.rical kinematic formul... 详细信息

关键词： integral geometry kinematic formula probability density Gaussian density

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Neuroinflammation as a th.rapeutic target in h.ntington's disease

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Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Th.lani h.Palpagama Center for Brain Research.and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Ph.rmacology and Th.rapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George h.ntington presented h.s essay “On Ch.rea” to th. Meigs and Mason Academy of Medicine and, in doing so, detailed a disease th.t would later bear h.s name. h.ntington's disease(h.) is a genetic, neurodegenerative disease th.t manifests as th. loss of motor control,cognitive impairment,and mood and psych.atric ch.nges in paents.

关键词： h.ntington inflammation Medicine

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