67,892 research outputs found

    Modelling and measurement accuracy enhancement of flue gas flow using neural networks

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    This paper discusses the modeling of the flue gas flow in industrial ducts and stacks using artificial neural networks (ANN's). Based upon the individual velocity and other operating conditions, an ANN model has been developed for the measurement of the volume flow rate. The model has been validated by the experiment using a case-study power plant. The results have shown that the model can largely compensate for the nonrepresentativeness of a sampling location and, as a result, the measurement accuracy of the flue gas flow can be significantly improved

    Graphs with 3-rainbow index n1n-1 and n2n-2

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    Let GG be a nontrivial connected graph with an edge-coloring c:E(G){1,2,,q},c:E(G)\rightarrow \{1,2,\ldots,q\}, qNq\in \mathbb{N}, where adjacent edges may be colored the same. A tree TT in GG is a rainbowtreerainbow tree if no two edges of TT receive the same color. For a vertex set SV(G)S\subseteq V(G), the tree connecting SS in GG is called an SS-tree. The minimum number of colors that are needed in an edge-coloring of GG such that there is a rainbow SS-tree for each kk-set SS of V(G)V(G) is called the kk-rainbow index of GG, denoted by rxk(G)rx_k(G). In \cite{Zhang}, they got that the kk-rainbow index of a tree is n1n-1 and the kk-rainbow index of a unicyclic graph is n1n-1 or n2n-2. So there is an intriguing problem: Characterize graphs with the kk-rainbow index n1n-1 and n2n-2. In this paper, we focus on k=3k=3, and characterize the graphs whose 3-rainbow index is n1n-1 and n2n-2, respectively.Comment: 14 page

    The semileptonic baryonic decay Ds+ppˉe+νeD_s^+\to p\bar p e^+ \nu_e

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    The decay Ds+ppˉe+νeD_s^+\to p \bar p e^+\nu_e with a proton-antiproton pair in the final state is unique in the sense that it is the only semileptonic baryonic decay which is physically allowed in the charmed meson sector. Its measurement will test our basic knowledge on semileptonic Ds+D_s^+ decays and the low-energy ppˉp\bar p interactions. Taking into account the major intermediate state contributions from η,η,f0(980)\eta, \eta', f_0(980) and X(1835)X(1835), we find that its branching fraction is at the level of 10910810^{-9} \sim 10^{-8}. The location and the nature of X(1835)X(1835) state are crucial for the precise determination of the branching fraction. We wish to trigger a new round of a careful study with the upcoming more data in BESIII as well as the future super tau-charm factory.Comment: final version, accepted for publication in Phys. Lett.