27,047 research outputs found

    Solutions of Conformal Turbulence on a Half Plane

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    Exact solutions of conformal turbulence restricted on a upper half plane are obtained. We show that the inertial range of homogeneous and isotropic turbulence with constant enstrophy flux develops in a distant region from the boundary. Thus in the presence of an anisotropic boundary, these exact solutions of turbulence generalize Kolmogorov's solution consistently and differ from the Polyakov's bulk case which requires a fine tunning of coefficients. The simplest solution in our case is given by the minimal model of p=2,q=33p=2, q=33 and moreover we find a fixed point of solutions when p,qp,q become large.Comment: 10pages, KHTP-93-07, SNUCTP-93-3

    Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit

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    We investigate the ionization dynamics of Argon atoms irradiated by an ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum distribution of the photoelectrons with near-zero-energy. We find a surprising accumulation in the momentum distribution corresponding to meV energy and a \textquotedblleft V"-like structure at the slightly larger transverse momenta. Semiclassical simulations indicate the crucial role of the Coulomb attraction between the escaping electron and the remaining ion at extremely large distance. Tracing back classical trajectories, we find the tunneling electrons born in a certain window of the field phase and transverse velocity are responsible for the striking accumulation. Our theoretical results are consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure

    Decision-making in real estate development : application of game theory

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    Decision making in real estate development projects has generally undergone a number of important changes over the last decades. This transition represented a shift from governmentally dominated top-down spatial planning to bottom-up, public-private engagement schemes in real estate development (Tam et al. 2009). The new policy implies pluricentric network steering – in which several public and private parties play a role – instead of traditional hierarchical top-down governmental steering

    Stagnation in Brownfield redevelopment

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    Purpose of this paper is two-folded. At first it explains the major problems that are causing stagnation in brownfield redevelopment. In addition, these problems given the context of the present multi-actor built environment are becoming more complex to observe. Therefore, this paper suggests also a prospective decisionmaking approach that is the most appropriate to observe and react on the given stagnation problems. Such an approach should be regarded as prescriptive-interactive decision-making approach, a barely established branch. This approach should offer models that have prescriptive as well as an interactive component enabling them to successfully cope with the multi-actor environment. Overall, this paper provides up-to-date insight on the brownfield stagnation by gradually introducing the nowadays major problems and offers a prospective decision-making approach how these problems could be tackled

    Shear and Layer Breathing Modes in Multilayer MoS2

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    We study by Raman scattering the shear and layer breathing modes in multilayer MoS2. These are identified by polarization measurements and symmetry analysis. Their positions change with the number of layers, with different scaling for odd and even layers. A chain model explains the results, with general applicability to any layered material, and allows one to monitor their thickness

    Co-doped Ceria: Tendency towards ferromagnetism driven by oxygen vacancies

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    We perform an electronic structure study for cerium oxide homogeneously-doped with cobalt impurities, focusing on the role played by oxygen vacancies and structural relaxation. By means of full-potential ab-initio methods, we explore the possibility of ferromagnetism as observed in recent experiments. Our results indicate that oxygen vacancies seem to be crucial for the appearance of a ferromagnetic alignment among Co impurities, obtaining an increasing tendency towards ferromagnetism with growing vacancy concentration. The estimated couplings cannot explain though, the experimentally observed room-temperature ferromagnetism. In this systematic study, we draw relevant conclusions regarding the location of the oxygen vacancies and the magnetic couplings involved. In particular, we find that oxygen vacancies tend to nucleate in the neighborhood of Co impurities and we get a remarkably strong ferromagnetic coupling between Co atoms and the Ce^{3+} neighboring ions. The calculated magnetic moments per cell depend on the degree of reduction which could explain the wide spread in the magnetization values observed in the experiments

    The new modelling method in urban development : case study in Rotterdam

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    Land-use transition, energy consumption, and temperature fluctuation are the three dominant topics we have investigated in this research. In the last century, 38 heat waves occurred in Europe, of which eleven were after 1900 and six after 2000 (IPCC, 2007). Local-climate changes due to urbanization are epitomized by the urban heat island (UHI), which mainly focuses on the interaction of land use and temperature. However, energy is also an important issue when we investigate the sustainable urban development. This research detects correlations between land-use transition, energy consumption, and temperature fluctuation in the Rotterdam area from 1996 till now. We use a series of maps to illustrate the relationship of temperature fluctuation and energy consumption. These two variables are linked via land-use maps. From the data set, the spatial parameters are estimated that have a significant effect on the correlation between temperature fluctuation and energy consumption. Finally we draw conclusions on the Rotterdam 2050 city scenario, taking the found spatial parameters into consideration
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