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101.
We have prepared organic guest molecules in which two pyridinium rings are connected through an aromatic/aliphatic bridge bearing a carboxyl group. The supramolecular interactions between these guests and macrocyclic hosts cucurbit[7]uril ( CB7 ) and cucurbit[8]uril ( CB8 ) has been studied. We have demonstrated that the binding modes of the complexes depend on the type of central bridge present in the guest molecules and the size of the macrocycle. We have also showed that the binding mode between cucurbiturils and guests with aromatic bridges is pH independent. On the other hand, a guest containing an aliphatic bridge and CB7 formed a pseudorotaxane, which behaved as a pH‐driven molecular switch. 相似文献
102.
Lanin AA Voronin AA Sokolov VI Fedotov IV Fedotov AB Akhmanov AS Panchenko VY Zheltikov AM 《Optics letters》2011,36(10):1788-1790
Slow-light effects induced by stimulated Raman scattering in polymer waveguides on a printed circuit board are shown to enable a widely tunable delay of broadband optical signals, suggesting an advantageous platform for optical information processing and ultrafast optical waveform transformation. 相似文献
103.
A new absorption band has been detected at 4009 cm?1 in stoichiometric LiNbO? single crystals. Based on present and earlier experiments and recent calculations, this band has been assigned as a combination transition involving the OH stretching and an OH librational mode. The librational mode participating in this combination is of lower fundamental frequency than that contributing to the combination band at 4415 cm1 observed by Gr?ne and Kapphan [J. Phys. Condens. Matter 7, 3051 (1995)]. 相似文献
104.
We study theoretically the possibility of performing temporal differentiation of optical signals using a resonant diffraction grating. We demonstrate that the resonant grating allows the calculation of the first-order derivative of an optical signal envelope in the vicinity of waveguide resonant frequencies in the zeroth transmitted diffraction order. The grating is shown to allow the calculation of the fractional derivative of order 1/2 in the vicinity of Rayleigh-Wood anomalies. Numerical simulations based on the rigorous coupled-wave analysis of Maxwell's equations demonstrate the high-quality differentiation of optical signals with temporal features in the picosecond range. 相似文献
105.
Möbius structure (on a set \(X\) ) is a class of metrics having the same cross-ratios. A Möbius structure is Ptolemaic if it is invariant under inversion operations. The boundary at infinity of a \(\mathrm{CAT }(-1)\) space is in a natural way a Möbius space, which is Ptolemaic. We give a free of classification proof of the following result that characterizes the rank one symmetric spaces of noncompact type purely in terms of their Möbius geometry: Let \(X\) be a compact Ptolemy space which contains a Ptolemy circle and allows many space inversions. Then \(X\) is Möbius equivalent to the boundary at infinity of a rank one symmetric space. 相似文献
106.
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stud. phil. Viktor Jeločnik 《Monatshefte für Chemie / Chemical Monthly》1903,24(7):526-532
Ohne ZusammenfassungZum Schlusse erfülle ich eine angenehme Pflicht, indem ich an dieser Stelle meinem hochverehrten Lehrer Herrn Hofrat Prof. Dr. Adolf Lieben für das wohlwollende Interesse und die zahlreichen Ratschläge, mit welchen er meine Arbeit jederzeit tatkräftig förderte, meinen innigstgefühlten Dank ausspreche.Auch bin ich Herrn Dr. Cäsar Pomeranz für die ersprießliche Mithilfe, welche er mir durch Rat und Tat angedeihen ließ, zu wärmstem Danke verpflichtet. 相似文献
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Viktor O. Iaroshenko Verena SpecowiusKatharina Vlach Marcelo Vilches-HerreraDmytro Ostrovskyi Satenik MkrtchyanAlexander Villinger Peter Langer 《Tetrahedron》2011,67(31):5663-5677
Difluoromethyl-containing heteroannulated pyridines, pyrimidines and pyrazoles are prepared by a two step method. The regioselective cyclizations of electron-excessive aminoheterocycles, hydrazines and amidines with CF2Cl-substituted 1,3-dicarbonyl compounds provide the corresponding CF2Cl-substituted heterocycles. Subsequent radical reactions with trimethylstannane or allyltrimethylstannane gave difluoromethyl-containing heteroannulated pyridines, pyrimidines and pyrazoles, respectively. 相似文献