474 research outputs found

    Pattern formation without heating in an evaporative convection experiment

    Get PDF
    We present an evaporation experiment in a single fluid layer. When latent heat associated to the evaporation is large enough, the heat flow through the free surface of the layer generates temperature gradients that can destabilize the conductive motionless state giving rise to convective cellular structures without any external heating. The sequence of convective patterns obtained here without heating, is similar to that obtained in B\'enard-Marangoni convection. This work present the sequence of spatial bifurcations as a function of the layer depth. The transition between square to hexagonal pattern, known from non-evaporative experiments, is obtained here with a similar change in wavelength.Comment: Submitted to Europhysics Letter

    Compact and explicit physical model for lateral metal-oxide-semiconductor field-effect transistor with nanoelectromechanical system based resonant gate

    Get PDF
    We propose a simple analytical model of a metal-oxide-semiconductor field-effect transistor with a lateral resonant gate based on the coupled electromechanical equations, which are self-consistently solved in time. All charge densities according to the mechanical oscillations are evaluated. The only input parameters are the physical characteristics of the device. No extra mathematical parameters are used to fit the experimental results. Theoretical results are in good agreement with the experimental data in static and dynamic operation. Our model is comprehensive and may be suitable for any electromechanical device based on the field-effect transduction

    First-principles study of ternary fcc solution phases from special quasirandom structures

    Get PDF
    In the present work, ternary Special Quasirandom Structures (SQSs) for a fcc solid solution phase are generated at different compositions, xA=xB=xC=13x_A=x_B=x_C=\tfrac{1}{3} and xA=12x_A=\tfrac{1}{2}, xB=xC=14x_B=x_C=\tfrac{1}{4}, whose correlation functions are satisfactorily close to those of a random fcc solution. The generated SQSs are used to calculate the mixing enthalpy of the fcc phase in the Ca-Sr-Yb system. It is observed that first-principles calculations of all the binary and ternary SQSs in the Ca-Sr-Yb system exhibit very small local relaxation. It is concluded that the fcc ternary SQSs can provide valuable information about the mixing behavior of the fcc ternary solid solution phase. The SQSs presented in this work can be widely used to study the behavior of ternary fcc solid solutions.Comment: 20 pages, 7 figure

    Matrix Factorizations and Homological Mirror Symmetry on the Torus

    Get PDF
    We consider matrix factorizations and homological mirror symmetry on the torus T^2 using a Landau-Ginzburg description. We identify the basic matrix factorizations of the Landau-Ginzburg superpotential and compute the full spectrum, taking into account the explicit dependence on bulk and boundary moduli. We verify homological mirror symmetry by comparing three-point functions in the A-model and the B-model.Comment: 41 pages, 9 figures, v2: reference added, minor corrections and clarifications, version published in JHE

    Charge Distributions in Metallic Alloys: a Charge Excess Functional theory approach

    Full text link
    Charge Distributions in Metallic Alloys: a Charge Excess Functional theory approachComment: 13 pages, 5 figure

    Pour un échantillonnage et un conseil agronomique raisonné, les outils d'aide à la décision

    Get PDF
    To a sampling and personal fertility advice, the tools for decision support. Environmental and agronomic issues require always more well thought and suited farmer management of agricultural inputs; soil analysis is therefore an essential tool to support decision. However, for a soil analysis to provide valuable information, it is essential for the sample to be representative of the studied field. Without this representativeness, an analytical result, as accurate as it could be, would not be of interest if it could mislead the farmer. In practice, the main difficulty for the sampler is the recognition of soil criteria which are essential to provide a fertility advice, especially in Wallonia (Belgium) where soil variability is very important. With the Digital Soil Map of Wallonia (DSMW), drowned at the scale 1/5,000, it seems appropriate to give these information to the samplers in an useful form for routine works. That is why a mapping tool for decision support, named REQUACARTO, was designed to be used for soil analysis by provincial laboratories, members of the REQUASUD laboratories network. This tool responds to a real requirement in Wallonia: achieving a quality sampling for the development of personalized soil fertility advice

    How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?

    Get PDF
    This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1).For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace changes in gene expression during cold acclimation that lead to an increase in cold tolerance. We used an RNA-Seq approach to investigate this in two species of the Drosophila virilis group. We found that the majority of genes that are differentially expressed during cold acclimation differ between the two species. Despite this, the biological processes associated with the differentially expressed genes were broadly similar in the two species. These included: metabolism, cell membrane composition, and circadian rhythms, which are largely consistent with previous work on cold acclimation/cold tolerance. In addition, we also found evidence of the involvement of the rhodopsin pathway in cold acclimation, a pathway that has been recently linked to thermotaxis. Interestingly, we found no evidence of differential expression of stress genes implying that long-term cold acclimation and short-term stress response may have a different physiological basis.PostprintPeer reviewe

    Tensor Product and Permutation Branes on the Torus

    Get PDF
    We consider B-type D-branes in the Gepner model consisting of two minimal models at k=2. This Gepner model is mirror to a torus theory. We establish the dictionary identifying the B-type D-branes of the Gepner model with A-type Neumann and Dirichlet branes on the torus.Comment: 26 page
    corecore