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S. Feng K. Halterman P.L. Overfelt J.M. Elson G.A. Lindsay M.J. Roberts 《Applied Physics A: Materials Science & Processing》2007,87(2):235-244
We present an overview of some of our work on transmission properties and mode characteristics of layered metamaterials and
their potential applications. In particular, we will show how layered metamaterials exhibit unusual transmission properties
and unconventional features of guided modes, such as resonance-induced transparency in multilayer structures and slope reversal
of dispersion curves in coupled waveguides.
PACS 78.67.-n; 73.21.Ac; 61.46.+w; 42.25.Bs; 42.82.Et 相似文献
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M.Mark Midland Ronald L. Halterman Charles A. Brown Angela Yamaichi 《Tetrahedron letters》1981,22(42):4171-4172
The isomerization of optically-active secondary propargyl alcohols, RCHOHCC(CH2)nCH3, to terminal acetylenic alcohols, RCHOH(CH2)n+1 C=CH, by potassium 3-aminopropylamide (KAPA) proceeds without loss of configuration at the hydroxy center. 相似文献
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Dye aggregation is detrimental to the performance of high optical density dye-doped photonic materials. To overcome this challenge,
the ability of cucurbit[7]uril (CB7) as a molecular host to disrupt aggregate formation on glass substrates was examined.
Rhodamine B was covalently attached to glass slides by initially coating the surface with azidohexylsiloxane followed by copper-catalyzed
“click” triazole formation with rhodamine B propargyl ester. The absorption and emission spectra of rhodamine B coated slides
in water indicated diverse heterogeneous properties as surface dye density varied. Fluorescence quenching due to dye aggregation
was evident at high surface dye density. Addition of aqueous cucurbit[7]uril (CB7) to the surface-tethered dyes perturbed
the spectra to reveal a considerable reduction in heterogeneity, which suggested that the presence of a surface in close proximity
does not significantly impair CB7’s ability to complex with tethered rhodamine B. 相似文献
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Halterman RL Pan X Martyn DE Moore JL Long AT 《The Journal of organic chemistry》2007,72(17):6454-6458
The conformational interconversions of four [2]catenanes (1-4) containing a dibenzo-34-crown-10 ether (BPP34C10) interlocked with rings containing two 4,4'-dipyridiniums tethered by 1,3-bis(ethyloxy)phenyl and bis(p-benzyl)methyl spacers have been studied by VT 1H NMR spectroscopy. Symmetrically placed blocking groups on thickened tethers enabled either pathway for circumrotation of the BPP34C10 between isoenergetic sites to be blocked. On the basis of chemical shifts of the BPP34C10, its internal p-hydroquinone forms pi-pi-stacking interactions with only one 4,4'-dipyridinium ring at a time. The activation barrier for migration along either open tether was approximately 11.5 kcal/mol. This study demonstrates an ability to select the pathway for conformational interconversions in these [2]catenanes containing the rigid bis(p-benzyl)methyl tether and the lowering the barrier for interconversion through destabilization of the ground state structures. 相似文献
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We have investigated the plasmonic resonance characteristics of canonical circular and square cylinders, with gap defects, that are illuminated by a plane wave. The circular and square cylinders have vee shaped gaps and constant width gaps, respectively. The electric and magnetic fields are obtained by solving the Lippmann–Schwinger equation from which we compute the far-field scattering cross-section and near-field local electromagnetic energy density.Numerical results are given for numerous wavelength and gap dimensions to qualitatively present the effects of gap defects on the scattering cross-section and local electromagnetic energy density. 相似文献
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The functional Ito formula, in the form df() = f( + d ) f(),is formulated and proved in the context of a Lie algebra L associatedwith a quantum (non-commutative) stochastic calculus. Here fis an element of the universal enveloping algebra U of L, andf() + d() f() is given a meaning using the coproductstructure of U even though the individual terms of this expressionhave no meaning. The Ito formula is equivalent to a chaoticexpansion formula for f() which is found explicitly. 1991 MathematicsSubject Classification: primary 81S25; secondary 60H05; tertiary18B25. 相似文献