992 research outputs found

    Tax Planning in Business Purchase Agreements, with Sample Clauses

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    The success or failure of the small- or medium-sized business is dependent primarily upon the ability of its key-men, who are generally the owners of the business. The death or retirement of one of these men, therefore, if not provided for, can cause havoc with the business to the detriment of the remaining shareholders or partners. This Article will consider the tax problems raised by the death of a stockholder and the death or retirement of a partner and the most practical and beneficial methods of anticipating and meeting those problems

    Characteristics of ferroelectric-ferroelastic domains in N{\'e}el-type skyrmion host GaV4_4S8_8

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    GaV4_4S8_8 is a multiferroic semiconductor hosting N{\'e}el-type magnetic skyrmions dressed with electric polarization. At Ts_s = 42K, the compound undergoes a structural phase transition of weakly first-order, from a non-centrosymmetric cubic phase at high temperatures to a polar rhombohedral structure at low temperatures. Below Ts_s, ferroelectric domains are formed with the electric polarization pointing along any of the four <111>\left< 111 \right> axes. Although in this material the size and the shape of the ferroelectric-ferroelastic domains may act as important limiting factors in the formation of the N{\'e}el-type skyrmion lattice emerging below TC_C=13\:K, the characteristics of polar domains in GaV4_4S8_8 have not been studied yet. Here, we report on the inspection of the local-scale ferroelectric domain distribution in rhombohedral GaV4_4S8_8 using low-temperature piezoresponse force microscopy. We observed mechanically and electrically compatible lamellar domain patterns, where the lamellae are aligned parallel to the (100)-type planes with a typical spacing between 100 nm-1.2 μ\mum. We expect that the control of ferroelectric domain size in polar skyrmion hosts can be exploited for the spatial confinement and manupulation of N{\'e}el-type skyrmions

    Relaxation at late stages in an entropy barrier model for glassy systems

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    The ground state dynamics of an entropy barrier model proposed recently for describing relaxation of glassy systems is considered. At stages of evolution the dynamics can be described by a simple variant of the Ehrenfest urn model. Analytical expression for the relaxation times from an arbitrary state to the ground state is derived. Upper and lower bounds for the relaxation times as a function of system size are obtained.Comment: 9 pages no figures. to appear in J.Phys. A: Math. and Ge

    Molecular diffusion on a time scale between nano- and milliseconds probed by field-cycling NMR relaxometry of intermolecular dipolar interactions: Application to polymer melts

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    A formalism is presented permitting the evaluation of the relative mean-squared displacement of molecules from the intermolecular contribution to spin-lattice relaxation dispersion of dipolar coupled spins. The only condition for the applicability is the subdiffusive power law character of the time dependence of the mean-squared displacement as it is typical for the chain mode regime in polymer liquids. Using field-cycling NMR relaxometry, an effective diffusion time range from nano- to almost milliseconds can be probed. The intermolecular spin-lattice relaxation contribution can be determined with the aid of isotopic dilution, that is, mixtures of undeuterated and deuterated molecules. Experiments have been performed with melts of polyethyleneoxide and polybutadiene. The mean-squared segment displacements have been evaluated as a function of time over five decades. The data can be described by a power law. The extrapolation to the much longer time scale of ordinary field-gradient NMR diffusometry gives good coincidence with literature data. The total time range thus covers nine decades. © 2007 American Institute of Physics

    Deuteron and proton spin-lattice relaxation dispersion of polymer melts: Intrasegment, intrachain, and interchain contributions

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    Proton and deuteron field-cycling NMR relaxometry was applied to deuterated and undeuterated bulk polyethyleneoxide and polybutadiene melts and mixtures thereof with molecular weights above the critical value. Spin-lattice relaxation data due to intrasegment (quadrupolar) couplings and intra- and interchain (dipolar) interactions were evaluated. Diverse dynamic limits are identified both with the proton and deuteron frequency dispersion data. The comparison between the intrachain and the interchain contributions leads to the conclusion that only model theories based on largely isotropic chain dynamics can account for the experimental findings. The extremely anisotropic character of the well-known tube/reptation model is too restrictive in this respect. © 2007 American Institute of Physics

    A Salt Metathesis Route To Ruthenium Carbene Complex Isomers With Pyridine Dicarboxamide-Derived Chelate Pincer Ligands

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    Reaction of the doubly deprotonated pyridine 2,6-dicarboxamido ligand (1) with (PCy_3)_2Cl_2 Ru=CHPh (3a) in THF gave a mixture of (lig)(PCy_3)Ru=CHPh isomers (4). The pentane soluble N,N,O-4 isomer was isolated by extraction and characterized by X-ray diffraction. The O,N, O-4 isomer was identified in the residue. Single crystals of the closely related complex (lig)(NHC) Ru=CHPh, O,N,O-5, were obtained from the reaction of 1 with (NHC)(PCy_3)Cl_2Ru=CHPh (3b) and used for the X-ray crystal structure analysis of the system

    Reversible Metal-Free Carbon Dioxide Binding by Frustrated Lewis Pairs

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    Frustrated Lewis pairs comprising phosphine and borane react to reversibly bind and release CO2, offering a rare example of metal-free CO2 sequestration. The mechanism of formation of CO2 derivatives by almost simultaneous P-C and O-B bond formation was characterized by quantum chemical calculations

    A Local Superlens

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    Superlenses enable near-field imaging beyond the optical diffraction limit. However, their widespread implementation in optical imaging technology so far has been limited by large-scale fabrication, fixed lens position, and specific object materials. Here we demonstrate that a dielectric lamella of subwavelength size in all three spatial dimensions behaves as a compact superlens that operates at infrared wavelengths and can be positioned to image any local microscopic area of interest on the sample. In particular, the lamella superlens may be placed in contact with any type of object and therefore enables examination of hard-to-scan samples, for example, with high topography or in liquids, without altering the specimen design. This lamella-based local superlens design is directly applicable to subwavelength light-based technology, such as integrated optics

    Microscopic Model of Charge Carrier Transfer in Complex Media

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    We present a microscopic model of a charge carrier transfer under an action of a constant electric field in a complex medium. Generalizing previous theoretical approaches, we model the dynamical environment hindering the carrier motion by dynamic percolation, i.e., as a medium comprising particles which move randomly on a simple cubic lattice, constrained by hard-core exclusion, and may spontaneously annihilate and re-appear at some prescribed rates. We determine analytically the density profiles of the "environment" particles, as seen from the stationary moving charge carrier, and calculate its terminal velocity as the function of the applied field and other system parameters. We realize that for sufficiently small external fields the force exerted on the carrier by the "environment" particles shows a viscous-like behavior and define an analog of the Stokes formula for such dynamic percolative environments. The corresponding friction coefficient is also derived.Comment: appearing in Chem. Phys. Special Issue on Molecular Charge Transfer in Condensed Media - from Physics and Chemistry to Biology and Nano-Engineering, edited by A.Kornyshev (Imperial College London), M.Newton (Brookhaven Natl Lab) and J.Ulstrup (Technical University of Denmark

    Lattice gas model in random medium and open boundaries: hydrodynamic and relaxation to the steady state

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    We consider a lattice gas interacting by the exclusion rule in the presence of a random field given by i.i.d. bounded random variables in a bounded domain in contact with particles reservoir at different densities. We show, in dimensions d3d \ge 3, that the rescaled empirical density field almost surely, with respect to the random field, converges to the unique weak solution of a non linear parabolic equation having the diffusion matrix determined by the statistical properties of the external random field and boundary conditions determined by the density of the reservoir. Further we show that the rescaled empirical density field, in the stationary regime, almost surely with respect to the random field, converges to the solution of the associated stationary transport equation
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