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1.
Bart M. J. M. Suijkerbuijk Duncan M. Tooke Anthony L. Spek Gerard van Koten Robertus J. M. Klein Gebbink Prof. Dr. 《无机化学与普通化学杂志》2007,633(15):2649-2653
A tin(IV) porphyrin was combined with two axial NCN‐pincer platinum(II) fragments by utilizing the oxophilicity of the apical positions on the tin atom and the acidic nature of the NCN‐pincer platinum derived benzoic acid. The solid‐state structure determined by X‐ray crystallography revealed some close contacts between the pincer complexes and the meso‐p‐tolyl subsitutents of the porphyrin. It was shown by 1H NMR spectroscopy that these close contacts were not present in solution and that this compound can potentially act as a novel building block for supramolecular architectures. 相似文献
2.
In this article, we show how to construct pairs of orthogonal pandiagonal Latin squares and panmagic squares from certain types of modular n‐queens solutions. We prove that when these modular n‐queens solutions are symmetric, the panmagic squares thus constructed will be associative, where for an n × n associative magic square A = (aij), for all i and j it holds that aij + an?i?1,n?j?1 = c for a fixed c. We further show how to construct orthogonal Latin squares whose modular difference diagonals are Latin from any modular n‐queens solution. As well, we analyze constructing orthogonal pandiagonal Latin squares from particular classes of non‐linear modular n‐queens solutions. These pandiagonal Latin squares are not row cyclic, giving a partial solution to a problem of Hedayat. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 221–234, 2007 相似文献
3.
Bart De Bruyn 《Journal of Algebraic Combinatorics》2006,24(1):23-29
Brouwer and Wilbrink [3] showed the nonexistence of regular near octagons whose parameters s, t2, t3 and t satisfy s ≥ 2, t2 ≥ 2 and t3 ≠ t2(t2+1). Later an arithmetical error was discovered in the proof. Because of this error, the existence problem was still open
for the near octagons corresponding with certain values of s, t2 and t3. In the present paper, we will also show the nonexistence of these remaining regular near octagons.
MSC2000 05B25, 05E30, 51E12
Postdoctoral Fellow of the Research Foundation - Flanders 相似文献
4.
Valuations of dense near polygons were introduced in 16 . In the present paper, we classify all valuations of the near hexagons ??1 and ??2, which are related to the respective Witt designs S(5,6,12) and S(5,8,24). Using these classifications, we prove that if a dense near polygon S contains a hex H isomorphic to ??1 or ??2, then H is classical in S. We will use this result to determine all dense near octagons that contain a hex isomorphic to ??1 or ??2. As a by‐product, we obtain a purely geometrical proof for the nonexistence of regular near 2d‐gons, d ≥ 4, whose parameters s, t, ti (0 ≤ i ≤ d) satisfy (s, t2, t3) = (2, 1, 11) or (2, 2, 14). The nonexistence of these regular near polygons can also be shown with the aid of eigenvalue techniques. © 2005 Wiley Periodicals, Inc. J Combin Designs 14: 214–228, 2006 相似文献
5.
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7.
In this paper, we analyze a discrete-time preemptive repeat priority queue with resampling. High-priority packets have preemptive
repeat priority, and interrupted low-priority packets are subjected to independent retransmission attempts. Both classes contain
packets with generally distributed transmission times. We show that the use of generating functions is beneficial for analyzing
the system contents and packet delay of both classes. The influence of the priority scheduling on the performance measures
is illustrated by some numerical examples.
This work has been supported by the Interuniversity Attraction Poles Programme–Belgian Science Policy. 相似文献
8.
9.
Atiya MS Chiang I Frank JS Haggerty JS Ito MM Kycia TF Li KK Littenberg LS Stevens A Strand RC Louis WC Akerib DS Marlow DR Meyers PD Selen MA Shoemaker FC Smith AJ Azuelos G Blackmore EW Bryman DA Felawka L Kitching P Kuno Y Macdonald JA Numao T Padley P Poutissou J Poutissou R Roy J 《Physical review letters》1990,65(1):21-24
10.
Zhang X Sieval AB Hummelen JC Hessen B 《Chemical communications (Cambridge, England)》2005,(12):1616-1618
Polyethene with fullerene moieties pendant on short-chain branches was prepared by the catalytic copolymerization of ethene and a fullerene-containing vinylic comonomer, yielding polyethene copolymers containing up to 25 wt% of C60. 相似文献