54,134 research outputs found

    Superconducting properties of Gd-Ba-Cu-O single grains processed from a new, Ba-rich precursor compound

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    Gd-Ba-Cu-O (GdBCO) single grains have been previously melt-processed successfully in air using a generic Mg-Nd-Ba-Cu-O (Mg-NdBCO) seed crystal. Previous research has revealed that the addition of a small amount of BaO2 to the precursor powders prior to melt processing can suppress the formation of Gd/Ba solid solution, and lead to a significant improvement in superconducting properties of the single grains. Research into the effects of a higher Ba content on single grain growth, however, has been limited by the relatively small grain size in the earlier studies. This has been addressed by developing Ba-rich precursor compounds Gd-163 and Gd-143, fabricated specifically to enable the presence of greater concentrations of Ba during the melt process. In this study, we propose a new processing route for the fabrication of high performance GdBCO single grain bulk superconductors in air by enriching the precursor powder with these new Ba rich compounds. The influence of the addition of the new compounds on the microstructures and superconducting properties of GdBCO single grains is reported

    Effect of depreciation of the public goods in spatial public goods games

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    In this work, depreciated effect of the public goods is considered in the public goods games, which is realized by rescaling the multiplication factor r of each group as r' = r(nc/G)^beta (beat>= 0). It is assumed that each individual enjoys the full profit of the public goods if all the players of this group are cooperators, otherwise, the value of the public goods is reduced to r'. It is found that compared with the original version (beta = 0), emergence of cooperation is remarkably promoted for beta > 0, and there exit optimal values of beta inducing the best cooperation. Moreover, the optimal plat of beta broadens as r increases. Furthermore, effect of noise on the evolution of cooperation is studied, it is presented that variation of cooperator density with the noise is dependent of the value of beta and r, and cooperation dominates over most of the range of noise at an intermediate value of beta = 1.0. We study the initial distribution of the multiplication factor at beta = 1.0, and find that all the distributions can be described as Gauss distribution

    Mixed integer nonlinear programming for Joint Coordination of Plug-in Electrical Vehicles Charging and Smart Grid Operations

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    The problem of joint coordination of plug-in electric vehicles (PEVs) charging and grid power control is to minimize both PEVs charging cost and energy generation cost while meeting both residential and PEVs' power demands and suppressing the potential impact of PEVs integration. A bang-bang PEV charging strategy is adopted to exploit its simple online implementation, which requires computation of a mixed integer nonlinear programming problem (MINP) in binary variables of the PEV charging strategy and continuous variables of the grid voltages. A new solver for this MINP is proposed. Its efficiency is shown by numerical simulations.Comment: arXiv admin note: substantial text overlap with arXiv:1802.0445

    Anti-lecture Hall Compositions and Overpartitions

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    We show that the number of anti-lecture hall compositions of n with the first entry not exceeding k-2 equals the number of overpartitions of n with non-overlined parts not congruent to 0,±10,\pm 1 modulo k. This identity can be considered as a refined version of the anti-lecture hall theorem of Corteel and Savage. To prove this result, we find two Rogers-Ramanujan type identities for overpartition which are analogous to the Rogers-Ramanjan type identities due to Andrews. When k is odd, we give an alternative proof by using a generalized Rogers-Ramanujan identity due to Andrews, a bijection of Corteel and Savage and a refined version of a bijection also due to Corteel and Savage.Comment: 16 page

    The Rogers-Ramanujan-Gordon Theorem for Overpartitions

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    Let Bk,i(n)B_{k,i}(n) be the number of partitions of nn with certain difference condition and let Ak,i(n)A_{k,i}(n) be the number of partitions of nn with certain congruence condition. The Rogers-Ramanujan-Gordon theorem states that Bk,i(n)=Ak,i(n)B_{k,i}(n)=A_{k,i}(n). Lovejoy obtained an overpartition analogue of the Rogers-Ramanujan-Gordon theorem for the cases i=1i=1 and i=ki=k. We find an overpartition analogue of the Rogers-Ramanujan-Gordon theorem in the general case. Let Dk,i(n)D_{k,i}(n) be the number of overpartitions of nn satisfying certain difference condition and Ck,i(n)C_{k,i}(n) be the number of overpartitions of nn whose non-overlined parts satisfy certain congruences condition. We show that Ck,i(n)=Dk,i(n)C_{k,i}(n)=D_{k,i}(n). By using a function introduced by Andrews, we obtain a recurrence relation which implies that the generating function of Dk,i(n)D_{k,i}(n) equals the generating function of Ck,i(n)C_{k,i}(n). We also find a generating function formula of Dk,i(n)D_{k,i}(n) by using Gordon marking representations of overpartitions, which can be considered as an overpartition analogue of an identity of Andrews for ordinary partitions.Comment: 26 page
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