23,767 research outputs found

    Absorption coefficients of oxygen at the Lyman-alpha line and its vicinity

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    Absorptivity of O2 near Lyman-alpha lin

    High pressure sintering of non-oxide materials

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    Pure materials of AIN, alpha-Si3N4 and TiC, without additives were sintered at 800 C to 1400 C under the pressures of 30 kbar and 50 kbar for 0.5 hours. The maximum density of sintered bodies for the cited materials was nearly 100% for AIN, 98% for TiC and 96% for alpha-Si3N4

    Energy Centroids of Spin II States by Random Two-body Interactions

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    In this paper we study the behavior of energy centroids (denoted as EIˉ\bar{E_I}) of spin II states in the presence of random two-body interactions, for systems ranging from very simple systems (e.g. single-jj shell for very small jj) to very complicated systems (e.g., many-jj shells with different parities and with isospin degree of freedom). Regularities of EIˉ\bar{E_I}'s discussed in terms of the so-called geometric chaoticity (or quasi-randomness of two-body coefficients of fractional parentage) in earlier works are found to hold even for very simple systems in which one cannot assume the geometric chaoticity. It is shown that the inclusion of isospin and parity does not "break" the regularities of EIˉ\bar{E_I}'s.Comment: four figures. to appear in Physical Review

    Quantum dynamics of non-relativistic particles and isometric embeddings

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    It is considered, in the framework of constrained systems, the quantum dynamics of non-relativistic particles moving on a d-dimensional Riemannian manifold M isometrically embedded in Rd+nR^{d+n}. This generalizes recent investigations where M has been assumed to be a hypersurface of Rd+1R^{d+1}. We show, contrary to recent claims, that constrained systems theory does not contribute to the elimination of the ambiguities present in the canonical and path integral formulations of the problem. These discrepancies with recent works are discussed.Comment: Revtex, 14 page

    Spin dependent fragmentation function at Belle

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    The measurement of the so far unknown chiral-odd quark transverse spin distribution in either semi-inclusive DIS (SIDIS) or inclusive measurements in pp collisions at RHIC has an additional chiral-odd fragmentation function appearing in the cross section. These chiral-odd fragmentation functions (FF) can for example be the so-called Collins FF or the Interference FF. HERMES has given a first hint that these FFs are nonzero, however in order to measure the transversity one needs these FFs to be precisely known. We have used 29.0 fb−1^{-1} of data collected by the Belle experiment at the KEKB e+e−e^+e^- collider to measure azimuthal asymmetries for different charge combinations of pion pairs and thus access the Collins FF.Comment: Results presented at the DIS 2006 conference in Tsukuba, Japa

    Effects of antibodies against dynein and tubulin on the stiffness of flagellar axonemes

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    Antidynein antibodies, previously shown to inhibit flagellar oscillation and active sliding of axonemal microtubules, increase the bending resistance of axonemes measured under relaxing conditions, but not the bending resistance of axonemes measured under rigor conditions. These observations suggest that antidynein antibodies can stabilize rigor cross-bridges between outer-doublet microtubules, by interfering with ATP-induced cross-bridge detachment. Stabilization of a small number of cross-bridge appears to be sufficient to cause substantial inhibition of the frequency of flagellar oscillation. Antitubulin antibodies, previously shown to inhibit flagellar oscillation without inhibiting active sliding of axonemal microtubules, do not increase the static bending resistance of axonemes. However, we observed a viscoelastic effect, corresponding to a large increase in the immediate bending resistance. This immediate bending resistance increase may be sufficient to explain inhibition of flagellar oscillation; but several alternative explanations cannot yet be excluded
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