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291.
Maclaughlin C.; Pedersen H.; Poon Y. S.; Salamon S. 《Journal London Mathematical Society》2006,73(1):173-193
We develop deformation theory for abelian invariant complexstructures on a nilmanifold, and prove that in this case theinvariance property is preserved by the Kuranishi process. Apurely algebraic condition characterizes the deformations leadingagain to abelian structures, and we prove that such deformationsare unobstructed. Various examples illustrate the resultingtheory, and the behavior possible in three complex dimensions. 相似文献
292.
Dyads of a N-confused porphyrin (NCP) moiety covalently linked to a porphyrin free-base (H2P) or a zinc(II) porphyrinate (ZnP) moiety via a flexible alkyl chain of variable length have been synthesized. Photoluminescence study demonstrated an efficient excitation energy transfer from H2P/ZnP moiety to the NCP moiety. Measurement of the near-IR emission of singlet oxygen produced by these dyads via photosensitization showed that the NCP-ZnP dyads (ФΔ = (0.61-0.65) ± 0.13) were better 1O2 generators than the NCP-P dyads (ФΔ = (0.36-0.41) ± 0.08). 相似文献
293.
We analyze side-coupled standing-wave cavity structures consisting of Fabry-Perot and photonic crystal resonators coupled to two waveguides. We show that optical bright and dark states, analogous to those observed in coherent light-matter interactions, can exist in these systems. These structures may be useful for variable, switchable delay lines. 相似文献
294.
Poon C Kaplan H Mayer PM 《European journal of mass spectrometry (Chichester, England)》2004,10(1):39-46
We investigated the effect of N-terminal amino group and carboxyl group methylation on peptide analysis by electrospray mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Permethylation of the N-terminal amino group and the carboxyl groups can reduce metal ion adducts but does not enhance sensitivity in electrospray as previously observed for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. N-terminal trimethylated peptides exhibit collision-induced dissociation (CID) tandem mass spectra that differ from their unmodified analogs; the results support the mobile proton hypothesis of peptide fragmentation. A permanent positive charge at the N-terminus leads to competition between permanent-charge directed processes and loss of the N-terminal trimethyl amino group. Carboxyl methylation has no effect on fragmentation behavior other than to shift the mass of fragments containing methylated carboxyl groups. Comparison of regular and tandem mass spectra of different methylated peptides allowed probing the location of incomplete methylation, the proton displaced by alkali metal ions and the purity of a mass-selected methylated peptide ion. 相似文献