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世界建筑导报 2006年第8期21卷 70-71页

作者： M.Robain R.Tisnado JF.Bonne A.Bretagnolle rh.arnaud LM.Fischer M.Lehmann R.Ayache 法国AS.建筑工作室

Deformation-and rupture-controlled friction between PDMS and a nanometer-scale SiO_(x) single-asperity

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Friction 2023年第9期11卷 1755-1770页

作者： arnaud CARON School of Energy Materials and Chemical EngineeringKoreaTech–Korea University of Technology and EducationCheonan 31253Republic of Korea

This work investigates the friction between polydimethylsiloxane(PDMS)and silicon oxide(SiO_(x))in single asperity sliding contact by atomic force microscopy(AFM).Two friction dependences on the normal force are identified:a tensile regime and a compressive regime of normal *** the compressive regime,friction is governed by the shear deformation and rupture of junctions between PDMS and SiO_(x).In this case,the shear strengthτ≈10 MPa is comparable with the cohesive strength of PDMS under compressive *** contrast,friction in the tensile regime is also affected by the elongation of the *** single SiO_(x)-asperity follows a stick–slip motion on PDMS in both normal force *** analysis of stick–slip as a function of the normal force allows determining the necessary amount of energy to break a SiO_(x)/PDMS *** between a SiO_(x)-asperity and a PDMS surface can be rationalized based on an energy criterion for the deformation and slippage of nanometer-scale junctions.

关键词： friction adhesion fracture atomic force microscopy(AFM) polydimethylsiloxane(PDMS)

On the Simpson index for the Wright–Fisher process with random selection and immigration

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International Journal of Biomathematics 2020年第6期13卷 77-111页

作者： arnaud Guillin Franck Jabot arnaud Personne Laboratoire d'Ingdnierie pour les Systemes Complexes IRSTEA Campus des Cezeaux 9 avenue Blaise Pascal-CS *** AubiereFrance

Moran or Wright–Fisher processes are probably the most well known models to study the evolution of a population under environmental various *** object of study will be the Simpson index which measures the level of diversity of the population,one of the key parameters for ecologists who study for example,forest *** ecological motivations,we will consider,here,the case,where there are various species with fitness and immigration parameters being random processes(and thus time evolving).The Simpson index is difficult to evaluate when the population is large,except in the neutral(no selection)case,because it has no closed *** approach relies on the large population limit in the“weak”selection case,and thus to give a procedure which enables us to approximate,with controlled rate,the expectation of the Simpson index at fixed *** will also study the long time behavior(invariant measure and convergence speed towards equilibrium)of the Wright–Fisher process in a simplified setting,allowing us to get a full picture for the approximation of the expectation of the Simpson index.

关键词： Simpson index multidimensional Wright-Fisher process random selection random immigration moment’s closure

PRECONDITIONED CONJUGATE GRADIENT METHODS FOR INTEGRAL EQUATIONS OF THE SECOND KIND DEFINED ON THE HALF-LINE

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Journal of Computational Mathematics 1996年第3期14卷 223-236页

作者： Chan, rh Lin, FR CHINESE UNIV HONG KONG DEPT MATHSHATINHONG KONG UNIV HONG KONG DEPT MATHHONG KONGHONG KONG

We consider solving integral equations of the second kind defined on the half-line [0, infinity) by the preconditioned conjugate gradient method. Convergence is known to be slow due to the non-compactness of the associated integral operator. In this paper, we construct two different circulant integral operators to be used as preconditioners for the method to speed up its convergence rate. We prove that if the given integral operator is close to a convolution-type integral operator, then the preconditioned systems will have spectrum clustered around 1 and hence the preconditioned conjugate gradient method will converge superlinearly. Numerical examples are given to illustrate the fast convergence.

关键词： Math Cr PRECONDITIONED CONJUGATE GRADIENT METHODS FOR INTEGRAL EQUATIONS OF THE SECOND KIND DEFINED ON THE HALF-LINE Pro III

QUASI-INTERPOLATING OPERATORS AND THEIR APPLICATIONS IN HYPERSINGULAR INTEGRALS

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Journal of Computational Mathematics 1998年第4期16卷 337-344页

作者： Wong, rh Lu, Y Dalian Univ Technol Inst Math Sci Dalian 116024 Peoples R China

The purpose of this paper is to propose and study a class of quasi-interpolating operators in multivariate spline space S-1/2(Delta(mn)(2*)) on non-uniform type-2 triangulation. Based on the operators, we construct cubature formula for two-dimensional hypersingular integrals. Some computing work have been done and the results are quite satisfactory.

关键词： hypersingular integral finite-part integral quasi-interpolating operator non-uniform type-2 triangulation

A SPLINE METHOD FOR SOLVING TWO-DIMENSIONAL FREDHOLM INTEGRAL EQUATION OF SECOND KIND WITH THE HYPERSINGULAR KERNEL

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Journal of Computational Mathematics 2001年第3期19卷 225-230页

作者： Wang, rh Lu, Y Dalian Univ Technol Inst Math Sci Dalian 116024 Peoples R China

Provides information on a study which proposed a spline method for solving two-dimensional Fredholm Integral Equations of second kind space with hypersingular kernels. Details on the quasi-interpolating operators; Inf... 详细信息

关键词： hypersingular integral finite-part integral quasi-interpolating operator nonuniform type-2 triangulation

PIECEWISE SEMIALGEBRAIC SETS

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Journal of Computational Mathematics 2005年第5期23卷 503-512页

作者： Zhu, CG Wang, rh Dalian Univ Technol Inst Math Sci Dalian 116024 Peoples R China

Semialgebraic sets are objects which are truly a special feature of real algebraic geometry. This paper presents the piecewise semialgebraic set, which is the subset of Rn satisfying a boolean combination of multivariate spline equations and inequalities with real coefficients. Moreover, the stability under projection and the dimension of C^μ piecewise semialgebraic sets are also discussed.

关键词： Algebraic geometry Semialgebraic geometry Tarski-Seidenberg Principle Multivariate splines Piecewise semialgebraic sets

A Sophisticated Network of Signaling Pathways Regulates Stomatal Defenses to Bacterial Pathogens

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Molecular Plant 2015年第4期8卷 566-581页

作者： Dominique arnaud Ildoo Hwang Department of Life Sciences POSTECH Biotech Center Pohang University of Science and Technology Pohang /90-/84 Korea

Guard cells are specialized cells forming stomatal pores at the leaf surface for gas exchanges between the plant and the atmosphere. Stomata have been shown to playan important role in plant defense as a part of the innate immune response. Plants actively close their stomata upon contact with microbes, thereby preventing pathogen entry into the leaves and the subsequent colonization of host tissues. In this review, we present current knowledge of molecular mechanisms and signaling pathways implicated in stomatal defenses, with particular emphasis on plant-bacteria interactions. Stomatal defense responses begin from the perception of pathogen-associated molecular patterns （PAMPs） and activate a signaling cascade involving the production of secondary messengers such as reactive oxygen species, nitric oxide, and calcium for the regulation of plasma membrane ion channels. The analyses on downstream molecular mechanisms implicated in PAMP-triggered stomatal closure have revealed extensive interplays among the components regulating hormonal signaling pathways. We also discuss the strategies deployed by pathogenic bacteria to counteract stomatal immunity through the example of the phytotoxin coronatine.

关键词： stomata immunity hydrogen peroxide nitric oxide calcium hormones

Impedance spectroscopy of the cell/nanovolcano interface enables optimization for electrophysiology

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Microsystems & Nanoengineering 2023年第3期9卷 297-308页

作者： Nicolas Maïno arnaud Bertsch Philippe Renaud Microsystems laboratory 4 Institute of Electrical and Micro EngineeringEcole Polytechique Fédérale de Lausanne(EPFL)LausanneSwitzerland

Volcano-shaped microelectrodes have demonstrated superior performance in measuring attenuated intracellular action potentials from cardiomyocyte cultures. However, their application to neuronal cultures has not yet yielded reliable intracellular access. This common pitfall supports a growing consensus in the field that nanostructures need to be pitched to the cell of interest to enable intracellular access. Accordingly, we present a new methodology that enables us to resolve the cell/probe interface noninvasively through impedance spectroscopy. This method measures changes in the seal resistance of single cells in a scalable manner to predict the quality of electrophysiological recordings. In particular, the impact of chemical functionalization and variation of the probe’s geometry can be quantitatively measured. We demonstrate this approach on human embryonic kidney cells and primary rodent neurons. Through systematic optimization, the seal resistance can be increased by as much as 20-fold with chemical functionalization, while different probe geometries demonstrated a lower impact. The method presented is therefore well suited to the study of cell coupling to probes designed for electrophysiology, and it is poised to contribute to elucidate the nature and mechanism of plasma membrane disruption by micro/nanostructures.

关键词： enable interface optimization

On the Controllability of an Advection-diffusion Equation with Respect to the Diffusion Parameter:Asymptotic Analysis and Numerical Simulations

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Acta Mathematicae Applicatae Sinica 2019年第1期35卷 54-110页

作者： Youcef AMIRAT arnaud MNCH Laboratoire de Mathématiques Blaise Pascal Université Clermont Auvergne UMR CNRS 6620 Campus universitaire des Cézeaux

The advection-diffusion equation y_t~ε-εy_(xx)~ε+ M y_x~ε= 0,(x, t) ∈(0, 1) ×(0, T) is null controllable for any strictly positive values of the diffusion coefficient ε and of the controllability time T. We discuss here the behavior of the cost of control when the coefficient ε goes to zero, according to the values of T. It is actually known that this cost is uniformly bounded with respect to ε if T is greater than a minimal time T_M, with T_M in the interval [1, 2×3^(1/2)]/M for M > 0 and in the interval [2×2^(1/2), 2(1 +3^(1/2))]/|M | for M < 0. The exact value of TM is however *** investigate in this work the determination of the minimal time T_M employing two distincts but complementary approaches. In a first one, we numerically estimate the cost of controllability, reformulated as the solution of a generalized eigenvalue problem for the underlying control operator, with respect to the parameter T and ε. This allows notably to exhibit the structure of initial data leading to large costs of control. At the practical level, this evaluation requires the non trivial and challenging approximation of null controls for the advection-diffusion equation. In the second approach, we perform an asymptotic analysis, with respect to the parameter ε, of the optimality system associated to the control of minimal L^2-norm. The matched asymptotic expansion method is used to describe the multiple boundary layers.

关键词： numerical approximation space-time variational formulation asymptotic analysis boundary layers null controllability