67,892 research outputs found

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

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 $n-1$ and $n-2$

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

### The semileptonic baryonic decay $D_s^+\to p\bar p e^+ \nu_e$

The decay $D_s^+\to p \bar p e^+\nu_e$ 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 $D_s^+$ decays and the low-energy
$p\bar p$ interactions. Taking into account the major intermediate state
contributions from $\eta, \eta', f_0(980)$ and $X(1835)$, we find that its
branching fraction is at the level of $10^{-9} \sim 10^{-8}$. The location and
the nature of $X(1835)$ 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.

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