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Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Ma.h.matics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： h.hOSSEINI O.BALILa.h.KI Department of Mechanical Engineering Faculty of EngineeringGolestan University

The effects of a.h.rmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a.h.rd boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is a.h.eved.

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

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

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

作者： Gefei Shi Zheng h.Zhu School of Aeronautics and Astronautics Sun Yat-sen UniversityGuangzhou 510275China Shenzhen Key Laboratory of Intelligent Microsatellite Constellation Shenzhen 518107China Department of Mechanical Engineering York University4700 Keele StreetTorontoCanada

This paper proposed a new libration decoupling analytical speed function(LD-ASF)in lieu of the classic analytical speed function to control the climber's speed along a partial space elevator to improve libration stability in cargo *** LD-ASF is further optimized for payload transportation efficiency by a novel coordinate game theory 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 the proposed LD-ASF and coordinate game-based model predictive control are demonstrated by computer *** results reveal that the optimized LD-ASF results in higher transportation speed,stable end body's libration,lower thrust fuel consumption,and more flexible optimization space than the classic analytical speed function.

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

FRACTIONAL ORDER BOUNDARY VALUE PROBLEM WITh INTEGRAL BOUNDARY CONDITIONS INVOLVING PETTIS INTEGRAL

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Acta Ma.h.matica Scientia 2011年第2期31卷 661-672页

作者： hussein a.h. Salem Department of Ma.h.matics Faculty of Sciences Alexandria University Department of Ma.h.matics Faculty of Sciences and Arts Taibah University

In this article, we investigate the existence of Pseudo solutions for some fractional order boundary value problem with integral boundary conditions in the Bana.h.space of continuous function equipped with its weak topology. The class of such problems constitute a very interesting and important class of problems. They include two, three, multi-point and nonlocal boundary-value problems as special cases. In our investigation, the right hand side of the above problem is assumed to be Pettis integrable function. To encompass the full scope of this article, we give an example illustrating the main result.

关键词： Fractional calculus Pseudo solution boundary value problem Pettis integrals

ON ThE GAUSSIAN KINEMATIC FORMULA OF *** AND ***

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

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

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

关键词： integral geometry kinematic formula probability density Gaussian density

Neuroinflammation as a therapeutic target in huntington's disease

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

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

In 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine

Glial response in the midcingulate cortex in huntington’s disease

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Neural Regeneration Research 2025年第1期20卷 207-208页

作者： Thulani h.Palpagama Andrea Kwakowsky Center for Brain Research and Department of Anatomy and Medical Imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CenterUniversity of GalwayGalwayIreland

huntington’s disease(hD)is a genetic disease characterized by the progressive degeneration of the striatum and *** can present with a variety of symptoms that can broadly be classified into motor symptoms,inclusive of choreatic movements and rigidity,mood and psychiatric symptoms,such as depression and apa.h.,and cognitive symptoms,such as cognitive *** causal mutation underlying hD results from an expansion of a CAG repeat sequence on the IT15 gene,resulting in the formation and accumulation of a mutant huntingtin protein.

关键词： huntington degeneration cortex

Comparative chemical sensor for detection of chromium(Ⅵ) in aqueous solution

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Optoelectronics Letters 2025年第1期21卷 21-27页

作者： Sura.h.AL-REKABI A.A.ALWAhIB Electrical Technique Department Al Suwayrah Technical InstituteMiddle Technical UniversityBaghdadIraq Laser and Optoelectronics Department University of Technology-IraqBaghdadIraq

A process for purifying aqueous solutions containing heavy and toxic metals such as chromium(Cr) has been *** of the extremely harmful pollutants in rivers and seawater is the heavy metal ions due to their direct impacts on human,animals and plants are hexavalent Cr(Ⅵ).Consequently,highly sensitive sensor to detect Cr is *** plasmon resonance(SPR) technique has attracted huge research interest in detecting heavy metals *** this study,three types of prism-based SPR sensor,gold(Au)/silver(Ag),Au/polyaniline(PANI) and Au/titanium dioxide(TiO_(2)) nanostructured films,are investigated as potential sensing material to detect the presence of Cr(Ⅵ) ions in *** base Au layer with thickness of 48.3 nm is deposited on a glass slide for all *** Au/Ag,Au/PANI nanofibers and Au/TiO_(2) sensor films,the Cr(Ⅵ) concentration is varied from 1 ppm to 15 ppm with sensitivity of 0.270 °ppm^(-1),0.082 °ppm^(-1) and 0.039 °ppm^(-1),*** on these results,the Au/PANI nanofibers are the most sensitive to Cr(Ⅵ) among the tested sensing materials.

关键词： chromium fibers silver

Investigation of Even-Even Ru Isotopes in Interacting Boson Model-2

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Communications in Theoretical Physics 2006年第4X期46卷 697-703页

作者： a.h. Yilmaz M. Kuruoglu Department of Physics Karadeniz Technical University Trabzon 61080 ~hrkey

The interacting boson model of Arima, Ia.h.llo, and co-workers is applied to the even ruthenium isotopes, ^96 Ru -116Ru. Excitation energies, electromagnetic transition strengths, quadrupole and magnetic dipole moments, and △（E2/M1） mixing ratios have been described systematically. Mixed symmetry states are investigated. It is seen that the properties of low-lying levels in these isotopes, for which the comparison between experiment and theory is possible, can be satisfactorily characterized by the Interacting Boson Model-2.

关键词： nuclear structure ^96Ru- ^116Ru energy levels interacting boson model-2

Electrical Properties of Li-doped P-type ZnO Ceramics

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Journal of Materials Science & Technology 2009年第3期25卷 314-318页

作者： a.h. Salama F.F. hammad Physical Chemistry Department National Research Center Inorganic Chemistry Department National Research Center

Li-doped p-type ZnO ceramics were prepared by conventional methods according to the chemical formula Zn1-xLixO2 where x=0.5, 1.0, 1.5 and 2.0 mole fraction, respectively. The crystal structures of the prepared samples were studied by X-ray diffraction analysis. The dielectric properties （including dielectric constant ε′ and dielectric loss ε″） and dc-electrical conductivity [σ（Ω^-***^-1）] were investigated. The dielectric constant ε′ was sharply decreased at the low frequency range and independent on frequency at high frequency range. Otherwise, the dielectric loss ε″ varied with frequency and showed absorption peak located from 200 hz to 4 khz and moved to higher frequency as the concentration of Li＋ doped increased. It was found that dcelectrical conductivity logσ varied from -9 to -5 and the energy gap width were calculated by using Arrhenius equation. The p-type conductivity of Li-doped ZnO may be attributed to the formation of a Lizn-Lii donor complex, which is limited by reducing the amount of Lii.

关键词： P-type ZnO ceramics Dielectric constant Dielectric loss dc-conductivity