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Journal of Computational mathematics 2009年第4期27卷 495-524页

作者： s.m.mefire LAmFA CNRS UMR 6140Université de Picardie33 r.Saint-Leu80039 Amiens Cedex 1France

From a limit model in electric field obtained by letting the frequency vanish in the time-harmonic maxwell equations, we consider a limit perturbation model in the tangential boundary trace of the curl of the electric field for localizing numerically certain small electromagnetic inhomogeneities, in a three-dimensional bounded domain. We introduce here two localization procedures resulting from the combination of this limit perturbation model with each of the following inversion processes： the Current Projection method and an Inverse Fourier method. Each localization procedure uses, as data, a finite number of boundary measurements, and is employed in the single inhomogeneity case; only the one based on an Inverse Fourier method is required in the multiple inhomogeneities case. Our localization approach is numerically suitable for the context of inhomogeneities that are not purely electric. We compare the numerical results obtained from the two localization procedures in the single inhomogeneity configuration, and describe, in various settings of multiple inhomogeneities, the results provided by the procedure based on an Inverse Fourier method.

关键词： Inverse problems maxwell equations Electric fields Inhomogeneities Elec-trical Impedance Tomography Current Projection method FFT Numerical boundarymeasurements Edge elements Least square systems Incomplete modified Gram-schmidt preconditioning.

NUmERICAL LOCALIZATION OF ELECTROmAGNETIC ImPERFECTIONs FROm A PERTURBATION FORmULA IN THREE DImENsIONs

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Journal of Computational mathematics 2008年第2期26卷 149-195页

作者： m.Asch s.m.mefire LAmFA Université de PicardieCNRs33rue Saint-Leu80039 AmiensFrance CmAP Ecole PolytechniqueCNRSRoute de Saclay91128 PalaiseauFrance

This work deals with the numerical localization of small electromagnetic inhomogeneities. The underlying inverse problem considers, in a three-dimensional bounded domain, the time-harmonic maxwell equations formulated in electric field. Typically, the domain contains a finite number of unknown inhomogeneities of small volume and the inverse problem attempts to localize these inhomogeneities from a finite number of boundary measurements. Our localization approach is based on a recent framework that uses an asymptotic expansion for the perturbations in the tangential boundary trace of the curl of the electric field. We present three numerical localization procedures resulting from the combination of this asymptotic expansion with each of the following inversion algorithms： the Current Projection method, the mUltiple signal Classification （mUsIC） algorithm, and an Inverse Fourier method. We perform a numerical study of the asymptotic expansion and compare the numerical results obtained from the three localization procedures in different settings.

关键词： Inverse problems maxwell equations Electric fields Three-dimensional inho-mogeneities Electrical impedance tomography Current projection method mUsIC algo-rithm FFT Edge elements Numerical boundary measurements

Numerical study of switching Behavior in Finite media subject to 3D Ferroelectric-Paraelectric Interactions and Inspection of Calibration Effects

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Numerical mathematics(Theory,methods and Applications) 2021年第1期14卷 113-143页

作者： P.-W.martelli s.m.mefire Universite de Lorraine CNRSIECLF-54000 NancyFrance

We study numerically the switching behavior aspects and calibration effects relative to finite media embedding fully a three-dimensional ferroelectric layer in a paraelectric *** approach makes use of the Ginzburg-Landau formalism in combination with the electrostatics *** associated discrete nonlinear system,which arises from finite element approximations,is solved by an inexact Newton *** resulting numerical experiments highlight the effects of a balance between the physical and geometrical *** particular,the same state switchings can be retrieved from different ferroelectric layer sizes by acting upon the physical characteristic of the paraelectric *** platelet samples are in parallelepipedic and cylindrical configurations involved in these experiments.

关键词： Electroactive media ferroelectricity electrostatics Ginzburg-Landau systems finite elements inexact Newton methods numerical simulations

Numerical study of solutions of the 3D Generalized Kadomtsev-Petviashvili Equations for Long Times

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Communications in Computational Physics 2009年第10期6卷 1022-1062页

作者： F.Hamidouche Y.mammeri s.m.mefire Laboratoire de mathematiques CNRS UMR 8628Universite Paris-Sud 1191405 Orsay CedexFrance Laboratoire de mathematiques–Paul Painleve CNRS UMR 8524Universite des Sciences et Technologies de Lille59655 Villeneuve d’Ascq CedexFrance Laboratoire Amienois de mathematique Fondamentale et Appliquee CNRS UMR 6140Universite de Picardie33 r.Saint-Leu80039 Amiens Cedex 1France

From a spectral method combined with a predictor-corrector scheme,we numerically study the behavior in time of solutions of the three-dimensional generalized Kadomtsev-Petviashvili *** a systematic way,the dispersion,... 详细信息

关键词： 3D-KP equations spectral method predictor-corrector method dispersion blow-up soliton transverse instability

EXPONENTIAL mEsH APPROXImATIONs FOR A 3D EXTERIOR PROBLEm IN mAGNETIC INDUCTION

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Journal of Computational mathematics 2005年第2期23卷 131-152页

作者： séraphinm.mefire LaboratoireAmiénoisdemathématiqueFondamentaleetAppliquée CNRSUMR6140UniversitddePicardieJules-Verne33r.Saint-Leu80039AmiensCedex1France

A numerical method combining the approaches of C.I. Goldstein and L.-A. Ying is used for the simulation in three-dimensional magnetostatics related to an exterior problem in magnetic induction. Recently introduced, this method is based on the use of a graded mesh obtained by gluing homothetic layers in the exterior domain and has been performed in the case of edge element discretizations. In this work, the theoretical and practical aspects of the method are inspected in the case of face element and volume element discretizations,for computing a magnetic induction. Error estimates, implementations, and numerical results are provided.

关键词： exterior problems magnetostatics mixed formulations graded meshes faceelements volume elements boundary elements truncations error estimates

sTATIC REGImE ImAGING OF LOCATIONs OF CERTAIN 3D ELECTROmAGNETIC ImPERFECTIONs FROm A BOUNDARY PERTURBATION FORmULA

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Journal of Computational mathematics 2014年第4期32卷 412-441页

作者： seraphin m. mefire IECL CNRS UMR 7502 Universite de Lorraine Faculte des Sciences et Technologies de Nancy 54506 Vandoeuvre-les-Nancy Cedex France

We are concerned, in a static regime, with a three-dimensional bounded domain of certain an imaging approach of the locations in electromagnetic imperfections. This approach is related to Electrical Impedance Tomography and makes use of a new perturbation formula in the electric fields. We present two localization procedures, from a Current Pro- jection method that deals with the single imperfection context and an inverse Fourier process that is devoted to multiple imperfections configurations. These procedures extend those that were described in our previous work, since operating for a broader class of settings. Namely, the localization is additionally performed for certain purely electric imperfections, as established from numerical simulations.

关键词： Inverse problems maxwell equations Electric fields Inhomogeneities Elec-trical lmpedanee Tomography Current Projection method FFT Numerical boundarymeasurements Random noise Edge elements Least square systems Incomplete modifiedGram-schmidt preconditioning.

Predicting maximum Lifespan Limits at mean menopausal Age

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Journal of mathematical Research with Applications 2025年第1期 133-142页

作者： m.sUmATHI s.ANTONY CARLA Department of mathematics N.M.S.S.Vellaichamy Nadar College Research scholar (Part-time) Madurai Kamaraj University

The age at which a woman enters natural menopause has also been associated to death from any cause. menopause is a natural component of aging that happens between the ages of 45 and 55, with the average menopausal age being 51. Previous research has revealed the age at which women reach menopause, but there is no evidence to support the link between menopause and longevity. We made a study in assessing the limits of maximum lifespan at menopausal age in our previous article. In this paper, we aim to predict the maximum lifespan of women at mean menopausal age.

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Impact of Zika virus non-structural protein mutations on hippocampal damage

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Neural Regeneration Research 2025年第8期20卷 2307-2308页

作者： Larissa m.G.Cassiano Roney s.Coimbra Neurogenômica/Imunopatologia Instituto RenéRachouFiocruzBelo HorizonteBrazil Departamento de Bioquímica e Imunologia Instituto de Ciências BiológicasUniversidade Federal de Minas GeraisBelo HorizonteBrazil

The Zika virus(ZIKV),a member of the Flaviviridae family,attracted worldwide attention for its connection to severe neurological effects,notably microcephaly in newborns,first reported during the 2015 epidemic in ***,its impact goes beyond fetal and neonatal abnormalities,also affecting the central nervous system(CNs)in both children and adults,leading to enduring cognitive and behavioral impairments.

关键词： damage fetal neonatal

Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

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Neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs Víctor Cilleros-mañé Laia Just-Borràs marta Balanyà-segura Aleksandra Polishchuk Laura Nadal marta Tomàs Carolina silvera-simón manel m.santafé maria A.Lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorB

Petrology of lherzolite xenoliths of Hossérésédévolcano(Adamawa plateau,Ngaoundéréarea,Cameroon)

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Acta Geochimica 2023年第5期42卷 817-831页

作者： O.F.Nkouandou J.m.Bardintzeff Fagny mefire Njankouo Ndassa A.A.sahabo H.Adama Department of Earth sciences Faculty of SciencesUniversity of NgaoundereP.O.Box.454NgaoundereCameroon Univ Paris-saclay Sciences de la TerreVolcanologie-PlanetologieUMR CNRS 8148 GEOPSBat.50491405 OrsayFrance Laboratoire de volcanologie Institut de Recherches Geologique et Minie`reB.P.370BueaCameroon

Numerous mantle xenoliths 6–12 cm in size and sub-angular to rounded in shape occur within mio-Pliocene basanite lavas of the monogenic volcano of Hossérésédé in the Adamawa *** of spinel lherzolite exhibit protogranular,equigranular or porphyroclastic *** chemical analyses show that olivine is highly magnesian(Fo_(88-90)),clinopyroxene crystals are diopside and augite(Wo_(41.6–49.6)En_(45.3–53.7)Fs_(4.2–6.2)),orthopyroxene crystals are enstatite(Wo 1.4–1.5 En_(88.6–89.0)Fs_(9.6–9.9))and spinel crystals are mainly Al-spinel associ-ated to minor *** temperatures and pressures through empirical formulas show that Hossérésédé noliths have equilibrated between 1085 and 1204℃and 1.08 to 1.57 GPa,corresponding to sampling depths of 36 and 52 *** petrographical and mineral chemistry of Hossérésédénoliths evidences the com-plex nature and composition of the subcontinental lithosphere under the Adamawa *** may involve a probable uplift of the whole area after a limited exten-sional event,possible metasomatism through melt infiltration during shearing of the lithospheric mantle along the Pan African strike-slip fault system.

关键词： Cameroon Adamawa Hossérésédé subcontinental lithosphere Xenolith Peridotite Lherzolite