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Testing semiochemicals from aphid, plant and conspecific： attraction of Harmonia axyridis

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Insect Science 2012年第3期19卷 372-382页

作者： Pascal D. Leroy Thomas Schillings Julien Farmakidis Stephanie Heuskin Georges Lognay Francois J. Verheggen Yves Brostaux Eric Haubruge Frederic Francis departments of Functional and Evolutionary Entomology departments of Analytical Chemistry departments of applied Statistics Computer Science and Mathematics University of Liege Gembloux Agro-Bio Tech Gembloux Belgium

Harmonia axyridis Pallas （Coleoptera： Coccinellidae） is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids （Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene）, from coccinellids （[-]-β-earyophyllene） and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds （[Z]-3- hexenol and [E]-2-hexenal） were extracted using a Clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while （-）-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the （Z）-3-hexenol oriented both males and females to the odor source. The （E）-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.

关键词： aphids attractant Harmonia axyridis plant semiochemicals wind-tunnel

Von Neumann Stability Analysis of DG-Like and PNPM-Like Schemes for PDEs with Globally Curl-Preserving Evolution of Vector Fields

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Communications on applied mathematics and Computation 2022年第3期4卷 945-985页

作者： Dinshaw S.Balsara Roger Käppeli Physics and ACMS departments University of Notre DameNotre DameINUSA Seminar for applied mathematics(SAM) Department of MathematicsETH ZürichCH-8092 ZurichSwitzerland

This paper examines a class of involution-constrained PDEs where some part of the PDE system evolves a vector field whose curl remains zero or grows in proportion to specified source *** PDEs are referred to as curl-free or curl-preserving,*** arise very frequently in equations for hyperelasticity and compressible multiphase flow,in certain formulations of general relativity and in the numerical solution of Schrödinger’s *** has shown that if nothing special is done to account for the curl-preserving vector field,it can blow up in a finite amount of simulation *** this paper,we catalogue a class of DG-like schemes for such *** retain the globally curl-free or curl-preserving constraints,the components of the vector field,as well as their higher moments,must be collocated at the edges of the *** are updated using potentials collocated at the vertices of the *** resulting schemes:(i)do not blow up even after very long integration times,(ii)do not need any special cleaning treatment,(iii)can oper-ate with large explicit timesteps,(iv)do not require the solution of an elliptic system and(v)can be extended to higher orders using DG-like *** methods rely on a spe-cial curl-preserving reconstruction and they also rely on multidimensional *** Galerkin projection,highly crucial to the design of a DG method,is now conducted at the edges of the mesh and yields a weak form update that uses potentials obtained at the verti-ces of the mesh with the help of a multidimensional Riemann solver.A von Neumann sta-bility analysis of the curl-preserving methods is conducted and the limiting CFL numbers of this entire family of methods are catalogued in this *** stability analysis confirms that with the increasing order of accuracy,our novel curl-free methods have superlative phase accuracy while substantially reducing *** also show that PNPM-like methods,which only evolve the lower moments while rec

关键词： PDEs Numerical schemes Mimetic Discontinuous Galerkin

Curl Constraint-Preserving Reconstruction and the Guidance it Gives for Mimetic Scheme Design

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Communications on applied mathematics and Computation 2023年第1期5卷 235-294页

作者： Dinshaw S.Balsara Roger Käppeli Walter Boscheri Michael Dumbser Physics and ACMS departments University of Notre DameNotre DameINUSA Seminar for applied mathematics(SAM) Department of MathematicsETH ZürichCH-8092 ZurichSwitzerland Department of mathematics and Computer Science University of FerraraFerraraItaly Laboratory of applied mathematics Department of CivilEnvironmental and Mechanical EngineeringUniversity of TrentoTrentoItaly

Several important PDE systems,like magnetohydrodynamics and computational electrodynamics,are known to support involutions where the divergence of a vector field evolves in divergence-free or divergence constraint-preserving ***,new classes of PDE systems have emerged for hyperelasticity,compressible multiphase flows,so-called firstorder reductions of the Einstein field equations,or a novel first-order hyperbolic reformulation of Schrödinger’s equation,to name a few,where the involution in the PDE supports curl-free or curl constraint-preserving evolution of a vector *** study the problem of curl constraint-preserving reconstruction as it pertains to the design of mimetic finite volume(FV)WENO-like schemes for PDEs that support a curl-preserving involution.(Some insights into discontinuous Galerkin(DG)schemes are also drawn,though that is not the prime focus of this paper.)This is done for two-and three-dimensional structured mesh problems where we deliver closed form expressions for the *** importance of multidimensional Riemann solvers in facilitating the design of such schemes is also *** two dimensions,a von Neumann analysis of structure-preserving WENOlike schemes that mimetically satisfy the curl constraints,is also *** shows the tremendous value of higher order WENO-like schemes in minimizing dissipation and dispersion for this class of *** results are also presented to show that the edge-centered curl-preserving(ECCP)schemes meet their design *** paper is the first paper that invents non-linearly hybridized curl-preserving reconstruction and integrates it with higher order Godunov *** its very design,this paper is,therefore,intended to be forward-looking and to set the stage for future work on curl involution-constrained PDEs.

关键词： PDEs Numerical schemes Mimetic

Gorenstein FP∞-Injective Modules and w-Noetherian Ring

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Algebra Colloquium 2022年第4期29卷 687-712页

作者： Shiqi Xing Xiaoqiang Luo Kui Hu College of applied mathematics Chengdu University of Information Technology Chengdu 610225China departments of mathematics Sichuan University of Arts and Science DazhouSichuan 635000China College of Science Southwest University of Science and Technology MianyangSichuan 621010China

We study some homological properties of Gorenstein FP∞-injective modules,and we prove(1)a ring R is not necessarily coherent if every Gorenstein FP∞-injective R-module is injective,and(2)a ring R is not necessarily coherent if every Gorenstein injective R-module is *** addition,we characterize w-Noetherian rings in terms of Gorenstein FP∞-injective modules,and we prove that a ring R is w-Noetherian if and only if every GV-torsion-free FP∞-injective R-module is Gorenstein FP∞-injective,if and only if any direct sum of GV-torsion-free FP∞-injective R-modules is Gorenstein FP∞-injective.

关键词： Gorenstein FP∞-injective module Gorenstein FP∞-dimension FP-module w-Noetherian ring

Coherence resonance in a noise-driven gene network regulated by small RNA

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Theoretical & applied Mechanics Letters 2014年第1期4卷 58-62页

作者： Yanan Zhu Jianwei Shen Yong Xu departments of applied mathematics Northwestern Polytechnical University Institute of applied mathematics Xuchang University

Small RNA has recently drawn more and more attention. In this paper, we concentrate on the influence of noises on gene network regulated by small RNA using chemical Langevin equation. It shows that the noise can cause oscillation when the oscillate does not occur in the corresponding deterministic system. The coherence of the noise induced oscillation reaches a maximum for an optimal intensity of noise, and the coherence resonance appears accordingly. The findings imply probably omnipresent importance of noise in the functioning process of living organism.

关键词： small RNA additive noise coherence resonance

Exploring the impacts of major events on the systemic risk of the international energy market

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Petroleum Science 2024年第2期21卷 1444-1457页

作者： Ming-Tao Zhao Su-Wan Lu Lian-Biao Cui School of Statistics and applied mathematics Anhui University of Finance and EconomicsBengbu233030AnhuiChina Anhui Province Key Laboratory of philosophy and Social Science of Low-Carbon Development and Carbon Finance Anhui University of Finance and EconomicsBengbu233030AnhuiChina

This study examines the systemic risk caused by major events in the international energy market(IEM)and proposes a management strategy to mitigate it. Using the tail-event driven network(TENET)method, this study constructed a tail-risk spillover network(TRSN) of IEM and simulated the dynamic spillover tail-risk process through the cascading failure mechanism. The study found that renewable energy markets contributed more to systemic risk during the Paris Agreement and the COVID-19pandemic, while fossil energy markets played a larger role during the Russia-Ukraine conflict. This study identifies systemically important markets(SM) and critical tail-risk spillover paths as potential sources of systemic risk. The research confirms that cutting off the IEM risk spillover path can greatly reduce systemic risk and the influence of SM. This study offers insights into the management of systemic risk in IEM and provides policy recommendations to reduce the impact of shock events.

关键词： International energy market Tail-risk spillover Cascading failure mechanism Systemic risk management

Experimental investigation of limit space charge accumulation mode operation in a semi-insulating GaAs photoconductive semiconductor switch

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Journal of Semiconductors 2013年第7期34卷 106-110页

作者：马湘蓉施卫向梅 departments of applied Physics Xi'an University of Technology Institute of Physics and Electronic Engineering Xinjiang Normal University

Experiments with the limited space-charge accumulation（LSA） mode of oscillation in a large gap semiinsulating （SI） GaAs photoconductive semiconductor switch（PCSS） are *** has been observed that growth and drift of a photo-activated charge domain（PACD） are quenched only when the bias voltage is more than twice the threshold *** original negative resistance characteristics are directly utilized in the LSA mode;during LSA operation the spatial average of the electric field varies over a large portion of the negative differential mobility region of the velocity-electric field *** work efficiency of an SI GaAs PCSS is remarkably enhanced by electric field excursions into the positive resistance region when the total electric field is only below the threshold part of the *** LSA mode can only operate in the certain conditions that satisfy the quenching of the accumulation layer and the smaller initial domain voltage.

关键词： GaAs photoconductive semiconductor switch limit space charge accumulate mode accumulation layer photo-activated charge domain

Transient Diffusion in Triangular Cylinders

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Advances in applied mathematics and Mechanics 2015年第6期7卷 818-826页

作者： C.Y.Wang departments of mathematics and Mechanical Engineering Michigan State UniversityEast LansingMI 48824USA

A heated triangular cylinder is suddenly cooled in a constant temperature *** transient heat conduction problem is transformed to the Helmholtz equation related to the vibration of *** the membrane analogy,exact analy... 详细信息

关键词： Diffusion heat conduction transient triangular.

Influence of Gravity and Taper on the Vibration of a Standing Column

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Advances in applied mathematics and Mechanics 2012年第4期4卷 483-495页

作者： C.Y.Wang departments of mathematics and Mechanical Engineering Michigan State UniversityEast LansingMI 48824USA

The stability and natural vibration of a standing tapered vertical column under its own weight are *** stability criteria are found for the pointy column and numerical stability boundaries are determined for the blunt tipped *** vibrations we use an accurate,efficient initial value numerical method for the first three *** kinds of columns with linear taper are *** the taper and the cross section shape of the column have large influences on the vibration *** is found that gravity decreases the frequency while the degree of taper may increase or decrease *** may occur in two different planes.

关键词： Vibration column taper weight