314 research outputs found

    Adsorption properties of several materials for solar adsorption cooling system

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    Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.It is important for an adsorption refrigeration system to use an appropriate adsorption material and the matched refrigerant. In the present study, the adsorption characteristic of the allochroic silica gel and three kinds of zeolite material to water-vapor have been investigated experimentally. Upon analyzing the variation of the material adsorption capacity exposed in moist air atmosphere of controlled temperature and humidity, the adsorption characteristic to water-vapor is verified, and the influence of the temperature and the pressure are correlated. The results show that the dynamic adsorption characteristic and the adsorption isotherm of the tested material is closely related to its microstructure such as the BET surface area, the distribution of the pore diameter, the porosity, and the bulk density, etc. In view of the application in the solar adsorption air conditioning, 5A-II and 13X-II zeolite shows relatively fast adsorption rate and their time to adsorption saturation state is short. The allochroic silica gel, 5A-II and 13X-II zeolite is of higher adsorption capacity, while the dynamic adsorption characteristic of 5A-I and ZSM-5 zeolite is more sensitive to the change of pressure. The adsorption isotherm of allochroic silica gel follows an exponential function and ZSM-5 and 5A-I zeolites shows a “S" curve, The latter may be more suitable for the solar adsorption cooling system in summer.cf201

    S and D Wave Mixing in High TcT_c Superconductors

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    For a tight binding model with nearest neighbour attraction and a small orthorhombic distortion, we find a phase diagram for the gap at zero temperature which includes three distinct regions as a function of filling. In the first, the gap is a mixture of mainly dd-wave with a smaller extended ss-wave part. This is followed by a region in which there is a rapid increase in the ss-wave part accompanied by a rapid increase in relative phase between ss and dd from 0 to π\pi. Finally, there is a region of dominant ss with a mixture of dd and zero phase. In the mixed region with a finite phase, the ss-wave part of the gap can show a sudden increase with decreasing temperature accompanied with a rapid increase in phase which shows many of the characteristics measured in the angular resolved photoemission experiments of Ma {\em et al.} in Bi2Sr2CaCu2O8\rm Bi_2Sr_2CaCu_2O_8Comment: 12 pages, RevTeX 3.0, 3 PostScript figures uuencoded and compresse

    In-plane and Out-of-plane Plasma Resonances in Optimally Doped La1.84Sr0.16CuO4

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    We addressed the inconsistency between the electron mass anisotropy ratios determined by the far-infrared experiments and DC conductivity measurements. By eliminating possible sources of error and increasing the sensitivity and resolution in the far-infrared reflectivity measurement on the single crystalline and on the polycrystalline La1.84Sr0.16CuO4, we have unambiguously identified that the source of the mass anisotropy problem is in the estimation of the free electron density involved in the charge transport and superconductivity. In this study we found that only 2.8 % of the total doping-induced charge density is itinerant at optimal doping. Our result not only resolves the mass anisotropy puzzle but also points to a novel electronic structure formed by the rest of the electrons that sets the stage for the high temperature superconductivity

    Coupling between planes and chains in YBa2Cu3O7 : a possible solution for the order parameter controversy

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    We propose to explain the contradictory experimental evidence about the symmetry of the order parameter in YBa2Cu3O7YBa_{2}Cu_{3}O_{7} by taking into account the coupling between planes and chains. This leads to an anticrossing of the plane and chain band. We include an attractive pairing interaction within the planes and a repulsive one between planes and chains, leading to opposite signs for the order parameter on planes and chains, and to nodes of the gap because of the anticrossing. Our model blends s-wave and d-wave features, and provides a natural explanation for all the contradictory experimentsComment: 13 pages, revtex, 2 uucoded figure

    Distinguishing d-wave from highly anisotropic s-wave superconductors

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    Systematic impurity doping in the Cu-O plane of the hole-doped cuprate superconductors may allow one to decide between unconvention al ("d-wave") and anisotropic conventional ("s-wave") states as possible candidates for the order parameter in these materials. We show that potential scattering of any strength always increases the gap minima of such s-wave states, leading to activated behavior in temperature with characteristic impurity concentration dependence in observable quantities such as the penetration depth. A magnetic component to the scattering may destroy the energy gap and give rise to conventional gapless behavior, or lead to a nonmonotonic dependence of the gap on impurity concentration. We discuss how experiments constrain this analysis.Comment: 5 page

    IL-21/type I interferon interplay regulates neutrophil-dependent innate immune responses to Staphylococcus aureus

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    Methicillin-resistant Staphylococcus aureus (MRSA) is a major hospital- and communityacquired pathogen, but the mechanisms underlying host-defense to MRSA remain poorly understood. Here, we investigated the role of IL-21 in this process. When administered intratracheally into wild-type mice, IL-21 induced granzymes and augmented clearance of pulmonary MRSA but not when neutrophils were depleted or a granzyme B inhibitor was added. Correspondingly, IL-21 induced MRSA killing by human peripheral blood neutrophils. Unexpectedly, however, basal MRSA clearance was also enhanced when IL-21 signaling was blocked, both in Il21r KO mice and in wild-type mice injected with IL-21R-Fc fusion-protein. This correlated with increased type I interferon and an IFN-related gene signature, and indeed antiIFNAR1 treatment diminished MRSA clearance in these animals. Moreover, we found that IFNb induced granzyme B and promoted MRSA clearance in a granzyme B-dependent fashion. These results reveal an interplay between IL-21 and type I IFN in the innate immune response to MRS

    Measurements of the observed cross sections for e+ee^+e^-\to exclusive light hadrons containing π0π0\pi^0\pi^0 at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV

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    By analyzing the data sets of 17.3, 6.5 and 1.0 pb1^{-1} taken, respectively, at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for e+eπ+ππ0π0e^+e^-\to \pi^+\pi^-\pi^0\pi^0, K+Kπ0π0K^+K^-\pi^0\pi^0, 2(π+ππ0)2(\pi^+\pi^-\pi^0), K+Kπ+ππ0π0K^+K^-\pi^+\pi^-\pi^0\pi^0 and 3(π+π)π0π03(\pi^+\pi^-)\pi^0\pi^0 at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay into these final states at 90% C.L..Comment: 7 pages, 2 figure

    Partial wave analysis of J/\psi \to \gamma \phi \phi

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    Using 5.8×107J/ψ5.8 \times 10^7 J/\psi events collected in the BESII detector, the radiative decay J/ψγϕϕγK+KKS0KL0J/\psi \to \gamma \phi \phi \to \gamma K^+ K^- K^0_S K^0_L is studied. The ϕϕ\phi\phi invariant mass distribution exhibits a near-threshold enhancement that peaks around 2.24 GeV/c2c^{2}. A partial wave analysis shows that the structure is dominated by a 0+0^{-+} state (η(2225)\eta(2225)) with a mass of 2.240.02+0.030.02+0.032.24^{+0.03}_{-0.02}{}^{+0.03}_{-0.02} GeV/c2c^{2} and a width of 0.19±0.030.04+0.060.19 \pm 0.03^{+0.06}_{-0.04} GeV/c2c^{2}. The product branching fraction is: Br(J/ψγη(2225))Br(η(2225)ϕϕ)=(4.4±0.4±0.8)×104Br(J/\psi \to \gamma \eta(2225))\cdot Br(\eta(2225)\to \phi\phi) = (4.4 \pm 0.4 \pm 0.8)\times 10^{-4}.Comment: 11 pages, 4 figures. corrected proof for journa
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