3,845 research outputs found

    (9S,13R,14S)-7,8-Didehydro-4-(4-iodo­benz­yloxy)-3,7-dimeth­oxy-17-methyl­morphinan-6-one monohydrate

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    In the title compound, C26H28INO4·H2O, benzene rings are inclined at a dihedral angle of 69.9 (1)°. The N-containing ring exhibits a chair conformation, while the other rings approximate to envelope conformations. In the crystal, the uncoordinated water mol­ecule forms inter­molecular O—H⋯O and O—H⋯N hydrogen bonds

    Strong decays of the ϕ(2170)\phi(2170) as a fully-strange tetraquark state

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    We study strong decays of the ϕ(2170)\phi(2170), along with its possible partner X(2436)X(2436), as two fully-strange tetraquark states of JPC=1J^{PC} = 1^{--}. We consider seven decay channels: ϕη\phi \eta, ϕη\phi \eta^\prime, ϕf0(980)\phi f_0(980), ϕf1(1420)\phi f_1(1420), h1(1415)ηh_1(1415) \eta, h1(1415)ηh_1(1415) \eta^\prime, and h1(1415)f1(1420)h_1(1415) f_1(1420). Some of these channels are kinematically possible, and we calculate their relative branching ratios through the Fierz rearrangement. Future experimental measurements on these ratios can be useful in determining the nature of the ϕ(2170)\phi(2170) and X(2436)X(2436). The ϕ(2170)\phi(2170) has been observed in the ϕf0(980)\phi f_0(980), ϕη\phi \eta, and ϕη\phi \eta^\prime channels, and we propose to further examine it in the h1(1415)ηh_1(1415) \eta channel. Evidences of the X(2436)X(2436) have been observed in the ϕf0(980)\phi f_0(980) channel, and we propose to verify whether this structure exists or not in the ϕη\phi \eta, ϕη\phi \eta^\prime, h1(1415)ηh_1(1415) \eta, and h1(1415)ηh_1(1415) \eta^\prime channels.Comment: 10 pages, 3 figures, 1 table, suggestions and comments are welcom

    A semi-analytical method for the dynamic analysis of cylindrical shells with arbitrary boundaries

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    The dynamic behavior of cylindrical shells with arbitrary boundaries is studied in this paper. Love's shell theory and Hamilton's principle are employed to derive the motion equations for cylindrical shells. A semi-analytical methodology, which incorporates Durbin's inverse Laplace transform, differential quadrature method and Fourier series expansion technique, is proposed to investigate this phenomenon. The use of the differential quadrature method provides a solution in terms of the axial direction whereas the use of Durbin's numerical inversion method generates a solution in the time domain. Comparison of calculated frequency parameters to that derived from the literature illustrates the effectiveness of the method. Specifically, convergence tests indicate that the present approach has a rapid convergence, the time-history response and the Navier's solution are in great agreement. Comparisons between time-history responses derived by two shell theories show that the results fit well with each other when the thickness-radius ratios are small enough. An analysis of the influences of boundaries on the time-history response of cylindrical shells indicates that the peak displacement is closely related to the degrees of freedom of boundaries. The influences of the length-radius ratios and the thickness-radius ratios on the peak displacement are further investigated

    Pair Production of Charged Higgs Bosons from Bottom-Quark Fusion

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    For very large values of tanβ\tan\beta, charged Higgs boson pair production at the Large Hadron Collider (LHC) from the scattering of two bottom quarks can proceed dominantly. We investigated the cross sections of charged Higgs boson pair production via the subprocess bbˉH+Hb\bar{b} \to H^+H^- at the LHC including the next-to-leading order (NLO) QCD corrections in the minimal supersymmetric standard model (MSSM). We find that the NLO QCD corrections can significantly reduce the dependence of the cross sections on the renormalization and factorization scales.Comment: small changes are mad

    (9S,13R,14S)-7,8-Didehydro-4-(4-fluoro­benz­yloxy)-3,7-dimeth­oxy-17-methyl­morphinan-6-one sesquihydrate

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    In the title sinomenine derivative, C26H28FNO4·1.5H2O, the dihedral angle between the two aromatic rings is 55.32 (6)°. The N-containing ring has an approximate chair conformation, while other two rings have approximate envelope and half-chair conformations. One water mol­ecule is located on a twofold symmetry axis. In the crystal, the water mol­ecules form O—H⋯O and O—H⋯N hydrogen bonds, bridging symmetry-related main mol­ecules

    Specular Andreev Reflection in Inversion-symmetric Weyl-semimetals

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    The electron-hole conversion at the normal-metal superconductor interface in inversion-symmetric Weyl semimetals is investigated with an effective two-band model. We find that the specular Andreev reflection of Weyl fermions has two unusual features. The Andreev conductance for s-wave BCS pairing states is anisotropic, depending on the angle between the line connecting a pair of Weyl points and the normal of the junction, due to opposite chirality carried by the paired electrons. For the Fulde-Ferrell-Larkin-Ovchinnikov pairing states, the Andreev reflection spectrum is isotropic and is independent of the finite momentum of the Cooper pairs

    Study on Spinnability of PP/PU Blends and Preparation of PP/PU Bi-component Melt Blown Nonwovens

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    Melt blown polymer blends offers a good way to combine two polymers in the same fiber generating nonwovens with new and novel properties. In this study, polypropylene (PP) and polyurethane (PU) were blended to prepare PP/PU bicomponent melt blown nonwovens. The spinnability of PP/PU composites was investigated and PP/PU bi-component nonwovens with compositions of 95/5, 90/10, 80/20 and 70/30 were prepared by using the melt blowing technique. The melt blown fibers exhibited a ‘sea-island’ structure with PP as the continuous phase and PU as the dispersed phase. When the content of PU in the blend was above 40 %, PP/PU melt blown nonwovens could not be produced due to fiber breaking. For PP/PU (90/10) nonwovens, it was found that the average fiber diameter decreased with increasing die to collector (DCD) and elevated hot air pressure

    The effects of the little Higgs models on ttˉh0t\bar{t} h^0 production via γγ\gamma \gamma collision at linear colliders

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    In the frameworks of the littlest Higgs(LHLH) model and its extension with T-parity(LHTLHT), we studied the associated ttˉh0t\bar th^0 production process e+eγγttˉh0e^+ e^- \to \gamma\gamma \to t \bar t h^0 at the future e+ee^+e^- linear colliders up to QCD next-to-leading order. We present the regions of sf\sqrt{s}-f parameter space in which the LHLH and LHTLHT effects can and cannot be discovered with the criteria assumed in this paper. The production rates of process γγttˉh0\gamma\gamma \to t \bar t h^0 in different photon polarization collision modes are also discussed. We conclude that one could observe the effects contributed by the LHLH or LHTLHT model on the cross section for the process e+eγγttˉh0e^+ e^- \to \gamma\gamma \to t \bar t h^0 in a reasonable parameter space, or might put more stringent constraints on the LHLH/LHTLHT parameters in the future experiments at linear colliders.Comment: 22 pages, 25 figures, version to appear in Phys. Rev.
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