4,008 research outputs found

    Screening and classification of ceramic powders

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    A summary is given of the classification technology of ceramic powders. Advantages and disadvantages of the wet and dry screening and classification methods are discussed. Improvements of wind force screening devices are described

    Investigation of the components of the NAL high Reynolds number two-dimensional wind tunnel. Part 4: Design, construction and performance of the exhaust silencer

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    Presented is a description of the design construction and performance of the exhaust silencer for the NAL high Reynolds number two-dimensional transonic blow down wind tunnel, which was completed in October 1979. The silencer is a two-storied construction made of reinforced concrete, 40 m. long, 10 m. wide and 19 m. high and entirely enclosed by thick concrete walls. The upstream part of the first story, particularly, is covered with double walls, the thickness of the two walls being 0.3 m. (inner wall) and 0.2 m. (outer wall), respectively. A noise reduction system using three kinds of parallel baffles and two kinds of lined bends is adopted for the wind tunnel exhaust noise

    Two character formulas for sl2^\hat{sl_2} spaces of coinvariants

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    We consider sl2^\hat{sl_2} spaces of coinvariants with respect to two kinds of ideals of the enveloping algebra U(sl_2\otimes\C[t]). The first one is generated by sl2tNsl_2\otimes t^N, and the second one is generated by eP(t),fR(t)e\otimes P(t), f\otimes R(t) where P(t),R(t)P(t), R(t) are fixed generic polynomials. (We also treat a generalization of the latter.) Using a method developed in our previous paper, we give new fermionic formulas for their Hilbert polynomials in terms of the level-restricted Kostka polynomials and qq-multinomial symbols. As a byproduct, we obtain a fermionic formula for the fusion product of sl3sl_3-modules with rectangular highest weights, generalizing a known result for symmetric (or anti-symmetric) tensors.Comment: LaTeX, 22 pages; very minor change

    Soliton solutions of the Kadomtsev-Petviashvili II equation

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    We study a general class of line-soliton solutions of the Kadomtsev-Petviashvili II (KPII) equation by investigating the Wronskian form of its tau-function. We show that, in addition to previously known line-soliton solutions, this class also contains a large variety of new multi-soliton solutions, many of which exhibit nontrivial spatial interaction patterns. We also show that, in general, such solutions consist of unequal numbers of incoming and outgoing line solitons. From the asymptotic analysis of the tau-function, we explicitly characterize the incoming and outgoing line-solitons of this class of solutions. We illustrate these results by discussing several examples.Comment: 28 pages, 4 figure

    Boosting automatic event extraction from the literature using domain adaptation and coreference resolution

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    Motivation: In recent years, several biomedical event extraction (EE) systems have been developed. However, the nature of the annotated training corpora, as well as the training process itself, can limit the performance levels of the trained EE systems. In particular, most event-annotated corpora do not deal adequately with coreference. This impacts on the trained systems' ability to recognize biomedical entities, thus affecting their performance in extracting events accurately. Additionally, the fact that most EE systems are trained on a single annotated corpus further restricts their coverage

    RF amplification property of the MgO-based magnetic tunnel junction using field-induced ferromagnetic resonance

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    The radio-frequency (RF) voltage amplification property of a tunnel magnetoresistance device driven by an RF external-magnetic-field-induced ferromagnetic resonance was studied. The proposed device consists of a magnetic tunnel junction (MTJ) and an electrically isolated coplanar waveguide. The input RF voltage applied to the waveguide can excite the resonant dynamics in the free layer magnetization, leading to the generation of an output RF voltage under a DC bias current. The dependences of the RF voltage gain on the static external magnetic field strength and angle were systematically investigated. The design principles for the enhancement of the gain factor are also discussed.Comment: 12 pages, 3 figure

    Enhanced tunability of thermodynamic stability of complex hydrides by the incorporation of H- anions

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    First-principles calculations were employed to investigate hypothetical complex hydrides (M,M')4FeH8 (M = Na, Li; M'=Mg, Zn, Y, Al). Besides complex anion [FeH6]4-, these materials contain two H- anions, which raise the total anionic charge state from tetravalent to hexavalent, and thereby significantly increasing the number of combinations of countercations. We have determined that similar to complex hydrides (M,M')2FeH6 containing only [FeH6]4-, the thermodynamic stability is tuned by the average cation electronegativity. Thus, the chemical flexibility provided by incorporating H- enhances the tunability of thermodynamic stability, which will be beneficial in obtaining optimal stability for hydrogen storage materials
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