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31.
We suggest an efficient route minimization heuristic for the vehicle routing problem with time windows. The heuristic is based on the ejection pool, powerful insertion and guided local search strategies. Experimental results on the Gehring and Homberger’s benchmarks demonstrate that our algorithm outperforms previous approaches and found 18 new best-known solutions. 相似文献
32.
Martiskainen O Juhász M Zalán Z Fülöp F Pihlaja K 《Rapid communications in mass spectrometry : RCM》2006,20(11):1621-1627
The electron ionization mass spectra of cis- and trans-fused 1,2,3,4,4a,5,6,7,8,8a-decahydro-1,3,2-benzodiazaphosphinine 2-oxides (1-17) were recorded, and the fragmentation pathways were established and compared with those of 1,4,4a,5,6,7,8,8a-octahydro-2H-3,1,2-benzoxazaphosphinine 2-oxides. In general, the mass spectral behaviors of the isomeric compounds were very similar and it was mostly impossible to differentiate them from each other on the basis of the relative abundances of their characteristic fragment ions. The compounds in which R(2) = Ph or OPh exhibited a series of common fragments, e.g. [R(2)H](+), R(2)PONHR(1(3)+), [M-C(3)H(7)](+) and [M-C(4)H(9)](+), the latter two ions being present in the spectra of only two of the derivatives with an N(CH(2)CH(2)Cl)(2) substituent on the P atom. When R(2) = Ph, numerous other alkyl radicals, alkenes and a cycloalkane were also ejected and these compounds also lost NH(2), NH(3), CH(3)N, CH(4)N or CH(3)NH(2). The compounds with an N(CH(2)CH(2)Cl)(2) substituent on the P atom most closely resembled their 3,1,2-O,N,P analogs in respect of the dominant role of this substituent. 相似文献
33.
Martiskainen O Sztanke K Matosiuk D Pihlaja K 《Rapid communications in mass spectrometry : RCM》2006,20(17):2548-2552
The electron ionization mass spectra of the title compounds (1: a R = H, b 2-CH(3), c 4-CH(3), d 2,3-diMe, e 2-OCH(3), f 4-OCH(3), g 2-Cl, h 3-Cl, i 4-Cl, j 3,4-diCl) were recorded at 70 eV to determine the effects of substituents and the possible keto-enol tautomerism. The compounds showed several common fragment ions but also fragment ions which divided them into three classes, namely 1a-1d (parent compound and Me-substituted derivatives), 1e and 1f (MeO-substituted derivatives), and 1g-1j (Cl-substituted derivatives). The presence of the HOCN(+.) ion as well as the exponential dependence of its total ion current in the case of p- and also 3-Cl-substituted compounds (1a, c, f, h-j) on the Hammett sigma constants and the loss of CHO or one or two HOCN moieties can be somewhat easier explained by the presence of the enol form but as a whole the results support the predominance of the keto form, in parallel to the situation in solution. 相似文献
34.
Yaar Dürüst Cevher Altu Jari Sinkkonen Olli Martiskainen Kalevi Pihlaja 《Journal of heterocyclic chemistry》2006,43(5):1267-1274
35.
In this paper we suggest, numerically simulate and discuss a tapered plasmonic nanostructure which allows efficient transmission of the wave beam energy into a weakly subwavelength (λ/4 … λ/2) spatial region within a broad frequency range. The frequency stable location of this region becomes possible due to unusual plasmonic modes we have theoretically revealed and used. Our structure is promising for prospective transducers between conventional optical waveguides and subwavelength nanoguides or nanocircuits. 相似文献
36.
Journal of Statistical Physics - The study and analysis of real-world social, communication, information and citation networks for understanding their structure and identifying interesting patterns... 相似文献
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Sobolev Spaces with Zero Boundary Values on Metric Spaces 总被引:6,自引:0,他引:6
We generalize the definition of the first order Sobolev spaces with zero boundary values to an arbitrary metric space endowed with a Borel regular measure. We show that many classical results extend to the metric setting. These include completeness, lattice properties and removable sets. 相似文献
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