27,014 research outputs found

    A computer solution for the dynamic load, lubricant film thickness, and surface temperatures in spiral-bevel gears

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    A computer method for determining the dynamic load between spiral bevel pinion and gear teeth contact along the path of contact is described. The dynamic load analysis governs both the surface temperature and film thickness. Computer methods for determining the surface temperature, and film thickness are presented along with results obtained for a pair of typical spiral bevel gears

    On C*-algebras related to constrained representations of a free group

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    We consider representations of the free group F2F_2 on two generators such that the norm of the sum of the generators and their inverses is bounded by μ∈[0,4]\mu\in[0,4]. These μ\mu-constrained representations determine a C*-algebra AμA_{\mu} for each μ∈[0,4]\mu\in[0,4]. We prove that these C*-algebras form a continuous bundle of C*-algebras over [0,4][0,4] and calculate their K-groups.Comment: 9 page

    Hadronic production of the PP-wave excited BcB_c-states (BcJ,L=1∗B_{cJ,L=1}^*)

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    Adopting the complete αs4\alpha_s^4 approach of the perturbative QCD (pQCD) and updated parton distribution functions, we have estimated the hadronic production of PP-wave excited BcB_c-states (BcJ,L=1∗B_{cJ,L=1}^*). In the estimate, special care on the relation of the production amplitude to the derivative of wave function at origin of the potential model is payed. For experimental references, main uncertainties are discussed, and the total cross sections and the distributions of the production with reasonable cuts at the energies of Tevatron and LHC are computed and presented. The results show that PP-wave production may contribute to the BcB_c-meson production indirectly by a factor about 0.5 of the direct production, and with such a big cross section, it is worth further to study the possibility to observe the PP-wave production itself experimentally.Comment: 23 pages, 9 figures, to replace for revising the misprints ec

    Well-posedness of the Viscous Boussinesq System in Besov Spaces of Negative Order Near Index s=−1s=-1

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    This paper is concerned with well-posedness of the Boussinesq system. We prove that the nn (n≥2n\ge2) dimensional Boussinesq system is well-psoed for small initial data (u⃗0,θ0)(\vec{u}_0,\theta_0) (∇⋅u⃗0=0\nabla\cdot\vec{u}_0=0) either in (B∞,1−1∩B∞,∞−1,1)×Bp,r−1({B}^{-1}_{\infty,1}\cap{B^{-1,1}_{\infty,\infty}})\times{B}^{-1}_{p,r} or in B∞,∞−1,1×Bp,∞−1,ϵ{B^{-1,1}_{\infty,\infty}}\times{B}^{-1,\epsilon}_{p,\infty} if r∈[1,∞]r\in[1,\infty], ϵ>0\epsilon>0 and p∈(n2,∞)p\in(\frac{n}{2},\infty), where Bp,qs,ϵB^{s,\epsilon}_{p,q} (s∈Rs\in\mathbb{R}, 1≤p,q≤∞1\leq p,q\leq\infty, ϵ>0\epsilon>0) is the logarithmically modified Besov space to the standard Besov space Bp,qsB^{s}_{p,q}. We also prove that this system is well-posed for small initial data in (B∞,1−1∩B∞,∞−1,1)×(Bn2,1−1∩Bn2,∞−1,1)({B}^{-1}_{\infty,1}\cap{B^{-1,1}_{\infty,\infty}})\times({B}^{-1}_{\frac{n}{2},1}\cap{B^{-1,1}_{\frac{n}{2},\infty}}).Comment: 18 page

    The meson BcB_c annihilation to leptons and inclusive light hadrons

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    The annihilation of the BcB_c meson to leptons and inclusive light hadrons is analyzed in the framework of nonrelativistic QCD (NRQCD) factorization. We find that the decay mode, which escapes from the helicity suppression, contributes a sizable fraction width. According to the analysis, the branching ratio due to the contribution from the color-singlet component of the meson BcB_c can be of order (10^{-2}). We also estimate the contributions from the color-octet components. With the velocity scaling rule of NRQCD, we find that the color-octet contributions are sizable too, especially, in certain phase space of the annihilation they are greater than (or comparative to) the color-singlet component. A few observables relevant to the spectrum of charged lepton are suggested, that may be used as measurements on the color-octet and color-singlet components in the future BcB_c experiments. A typical long distance contribution in the annihilation is estimated too.Comment: 26 pages, 5 figures (6 eps-files), submitted to Phys. Rev.

    Three-Way Entanglement and Three-Qubit Phase Gate Based on a Coherent Six-Level Atomic System

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    We analyze the nonlinear optical response of a six-level atomic system under a configuration of electromagnetically induced transparency. The giant fifth-order nonlinearity generated in such a system with a relatively large cross-phase modulation effect can produce efficient three-way entanglement and may be used for realizing a three-qubit quantum phase gate. We demonstrate that such phase gate can be transferred to a Toffoli gate, facilitating practical applications in quantum information and computation.Comment: 10 pages, 2 figure

    Amine-terminated nanoparticle films: pattern deposition by a simple nanostencilling technique and stability studies under X-ray irradiation

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    Exploring the surface chemistry of nanopatterned amine-terminated nanoparticle films.</p
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