1,617 research outputs found

    Solving Inverse Conductivity Problems In Doubly Connected Domains By the Homogenization Functions of Two Parameters

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    In the paper, we make the first attempt to derive a family of two-parameter homogenization functions in the doubly connected domain, which is then applied as the bases of trial solutions for the inverse conductivity problems. The expansion coefficients are obtained by imposing an extra boundary condition on the inner boundary, which results in a linear system for the interpolation of the solution in a weighted Sobolev space. Then, we retrieve the spatial- or temperature-dependent conductivity function by solving a linear system, which is obtained from the collocation method applied to the nonlinear elliptic equation after inserting the solution. Although the required data are quite economical, very accurate solutions of the space-dependent and temperature-dependent conductivity functions, the Robin coefficient function and also the source function are available. It is significant that the nonlinear inverse problems can be solved directly without iterations and solving nonlinear equations. The proposed method can achieve accurate results with high efficiency even for large noise being imposed on the input data

    Continuous dechlorination of tetrachloroethene in an upflow anaerobic sludge blanket reactor

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    Influences of hydraulic retention time (HRT) on dechlorination of tetrachloroethene (PCE) were investigated in an upflow anaerobic sludge blanket (UASB) reactor inoculated with anaerobic granular sludge non-pre-exposed to chlorinated compounds. PCE was introduced into the reactor at a loading rate of 3 mg/l d. PCE removal increased from 51 +/- 5% to 87 +/- 3% when HRT increased from 1 to 4 d, corresponding to an increase in the PCE biotransformation rate from 10.5 +/- 2.3 to 21.3 +/- 3.7 mu mol/d. A higher ethene production rate, 0.9 +/- 0.2 mu mol/d, was attained without accumulation of dichloroethenes at the HRT of 4 d. Dehalococcoides-like species were detected in sludge granules by fluorescence in situ hybridization, with signal strength in proportion to the extent of PCE dechlorination

    The rare top quark decays tcVt\to cV in the topcolor-assisted technicolor model

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    We consider the rare top quark decays in the framework of topcolor-assisted technicolor (TC2) model. We find that the contributions of top-pions and top-Higgs predicted by the TC2 model can enhance the SM branching ratios by as much as 6-9 orders of magnitude. i.e., in the most case, the orders of magnitude of branching ratios are Br(tcg)105Br(t\to c g)\sim 10^{-5}, Br(tcZ)105Br(t\to c Z)\sim 10^{-5}, Br(tcγ)107Br(t\to c \gamma)\sim 10^{-7}. With the reasonable values of the parameters in TC2 model, such rare top quark decays may be testable in the future experiments. So, rare top quark decays provide us a unique way to test TC2 model.Comment: 14 pages, 4 figure

    The flavor-changing bottom-strange quark production in the littlest Higgs model with T parity at the ILC

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    In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the special flavor structures and some new flavor-changing (FC) couplings which could greatly enhance the production rates of the FC processes. We in this paper study some bottom and anti-strange production processes in the LHT model at the International Linear Collider (ILC), i.e., e+ebsˉe^+e^-\rightarrow b\bar{s} and γγbsˉ\gamma\gamma\rightarrow b\bar{s}. The results show that the production rates of these processes are sizeable for the favorable values of the parameters. Therefore, it is quite possible to test the LHT model or make some constrains on the relevant parameters of the LHT through the detection of these processes at the ILC.Comment: 12 pages, 8 figure

    Loop effects and non-decoupling property of SUSY QCD in gbtHg b\to tH^{-}

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    One-loop SUSY QCD radiative correction to gbtHgb \to tH^{-} cross section is calculated in the Minimal Supersymmetric Standard Model. We found that SUSY QCD is non-decoupling if the gluino mass and the parameter μ\mu, AtA_t or AbA_b are at the same order and get large. The non-decoupling contribution can be enhanced by large tanβ\tan\beta and therefore large corrections to the hadronic production rates at the Tevatron and LHC are expected in the large tanβ\tan\beta limit. The fundamental reason for such non-decoupling behavior is found to be some couplings in the loops being proportional to SUSY mass parameters.Comment: 15 pages, 5 PS figures. A proof of non-decouplings of SUSY-QCD, Comments on corresponding QCD correction and references adde

    Immersed boundary-finite element model of fluid-structure interaction in the aortic root

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    It has long been recognized that aortic root elasticity helps to ensure efficient aortic valve closure, but our understanding of the functional importance of the elasticity and geometry of the aortic root continues to evolve as increasingly detailed in vivo imaging data become available. Herein, we describe fluid-structure interaction models of the aortic root, including the aortic valve leaflets, the sinuses of Valsalva, the aortic annulus, and the sinotubular junction, that employ a version of Peskin's immersed boundary (IB) method with a finite element (FE) description of the structural elasticity. We develop both an idealized model of the root with three-fold symmetry of the aortic sinuses and valve leaflets, and a more realistic model that accounts for the differences in the sizes of the left, right, and noncoronary sinuses and corresponding valve cusps. As in earlier work, we use fiber-based models of the valve leaflets, but this study extends earlier IB models of the aortic root by employing incompressible hyperelastic models of the mechanics of the sinuses and ascending aorta using a constitutive law fit to experimental data from human aortic root tissue. In vivo pressure loading is accounted for by a backwards displacement method that determines the unloaded configurations of the root models. Our models yield realistic cardiac output at physiological pressures, with low transvalvular pressure differences during forward flow, minimal regurgitation during valve closure, and realistic pressure loads when the valve is closed during diastole. Further, results from high-resolution computations demonstrate that IB models of the aortic valve are able to produce essentially grid-converged dynamics at practical grid spacings for the high-Reynolds number flows of the aortic root

    Charm multiplicity and the branching ratios of inclusive charmless b quark decays in the general two-Higgs-doublet models

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    In the framework of general two-Higgs-doublet models, we calculate the branching ratios of various inclusive charmless b decays by using the low energy effective Hamiltonian including next-to-leading order QCD corrections, and examine the current status and the new physics effects on the determination of the charm multiplicity ncn_c and semileptonic branching ratio BSLB_{SL}. Within the considered parameter space, the enhancement to the ratio BR(bsg)BR(b \to s g) due to the charged-Higgs penguins can be as large as a factor of 8 (3) in the model III (II), while the ratio BR(bnocharm)BR(b \to no charm) can be increased from the standard model prediction of 2.49% to 4.91% (2.99%) in the model III (II). Consequently, the value of BSLB_{SL} and ncn_c can be decreased simultaneously in the model III. The central value of BSLB_{SL} will be lowered slightly by about 0.003, but the ratio ncn_c can be reduced significantly from the theoretical prediction of nc=1.28±0.05n_c= 1.28 \pm 0.05 in the SM to nc=1.23±0.05n_c= 1.23 \pm 0.05, 1.18±0.051.18 \pm 0.05 for mH+=200,100m_{H^+}=200, 100 GeV, respectively. We find that the predicted ncn_c and the measured ncn_c now agree within roughly one standard deviation after taking into account the effects of gluonic charged Higgs penguins in the model III with a relatively light charged Higgs boson.Comment: 25 pages, Latex file, axodraw.sty, 6 figures. Final version to be published in Phys.Rev.

    Azimuthal asymmetries in lepton-pair production at a fixed-target experiment using the LHC beams (AFTER)

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    A multi-purpose fixed-target experiment using the proton and lead-ion beams of the LHC was recently proposed by Brodsky, Fleuret, Hadjidakis and Lansberg, and here we concentrate our study on some issues related to the spin physics part of this project (referred to as AFTER). We study the nucleon spin structure through pppp and pdpd processes with a fixed-target experiment using the LHC proton beams, for the kinematical region with 7 TeV proton beams at the energy in center-of-mass frame of two nucleons s=115\sqrt{s}=115 GeV. We calculate and estimate the cos2ϕ\cos2\phi azimuthal asymmetries of unpolarized pppp and pdpd dilepton production processes in the Drell--Yan continuum region and at the ZZ-pole. We also calculate the sin(2ϕϕS)\sin(2\phi-\phi_S), sin(2ϕ+ϕS)\sin(2\phi+\phi_S) and sin2ϕ\sin2\phi azimuthal asymmetries of pppp and pdpd dilepton production processes with the target proton and deuteron longitudinally or transversally polarized in the Drell--Yan continuum region and around ZZ resonances region. We conclude that it is feasible to measure these azimuthal asymmetries, consequently the three-dimensional or transverse momentum dependent parton distribution functions (3dPDFs or TMDs), at this new AFTER facility.Comment: 15 pages, 40 figures. Version accepted for publication in EPJ

    Type IIB Solutions with Interpolating Supersymmetries

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    We study type IIB supergravity solutions with four supersymmetries that interpolate between two types widely considered in the literature: the dual of Becker and Becker's compactifications of M-theory to 3 dimensions and the dual of Strominger's torsion compactifications of heterotic theory to 4 dimensions. We find that for all intermediate solutions the internal manifold is not Calabi-Yau, but has SU(3) holonomy in a connection with a torsion given by the 3-form flux. All 3-form and 5-form fluxes, as well as the dilaton, depend on one function appearing in the supersymmetry spinor, which satisfies a nonlinear differential equation. We check that the fields corresponding to a flat bound state of D3/D5-branes lie in our class of solutions. The relations among supergravity fields that we derive should be useful in studying new gravity duals of gauge theories, as well as possibly compactifications.Comment: 27pp, v2 REVTeX4, typographical fixes and minor clarifications, v3 added ref, modified discussion of RR axion slightl

    Topological doping and the stability of stripe phases

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    We analyze the properties of a general Ginzburg-Landau free energy with competing order parameters, long-range interactions, and global constraints (e.g., a fixed value of a total ``charge'') to address the physics of stripe phases in underdoped high-Tc and related materials. For a local free energy limited to quadratic terms of the gradient expansion, only uniform or phase-separated configurations are thermodynamically stable. ``Stripe'' or other non-uniform phases can be stabilized by long-range forces, but can only have non-topological (in-phase) domain walls where the components of the antiferromagnetic order parameter never change sign, and the periods of charge and spin density waves coincide. The antiphase domain walls observed experimentally require physics on an intermediate lengthscale, and they are absent from a model that involves only long-distance physics. Dense stripe phases can be stable even in the absence of long-range forces, but domain walls always attract at large distances, i.e., there is a ubiquitous tendency to phase separation at small doping. The implications for the phase diagram of underdoped cuprates are discussed.Comment: 18 two-column pages, 2 figures, revtex+eps
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