نتایج جستجو برای: optical rotation
تعداد نتایج: 333642 فیلتر نتایج به سال:
Cholesteric elastomers possess a macroscopic "phase chirality" as the director n rotates in a helical fashion along an optical axis z and can be described by a chiral order parameter alpha. This parameter can be tuned by changing the helix pitch p and the elastic properties of the network at formation. The cholesterics also possess a local nematic order, changing with temperature or during solv...
Coupled split-ring-resonator metamaterials have previously been shown to exhibit large coupling effects, which are a prerequisite for obtaining large effective optical activity. By a suitable lateral arrangement of these building blocks, we completely eliminate linear birefringence and obtain pure optical activity and connected circular optical dichroism. Experiments around a 100 THz frequency ...
Two new supramolecular complexes consisting of an achiral bisporphyrin host and a chiral diamine guest are reported. One shows a remarkably high amplitude bisignate CD signal while the other one shows a very low value. X-ray structure and other spectroscopic investigations of the tweezer complexes clearly rationalize the origin of the optical activity that has so far remained an unresolved issue.
We report on the optical and magneto-optical response of hybrid plasmonic lattices that consist of pure nickel and gold nanoparticles in a checkerboard arrangement. Diffractive far-field coupling between the individual emitters of the lattices results in the excitation of two orthogonal surface lattice resonance modes. Local analyses of the radiation fields indicate that both the nickel and gol...
Physics, Moscow, RussiaWe consider cholesteric liquid-crystalline DNA dispersions, and show thatpolymeric (Dau-Cu) complexes, the so-called bridges, between pairs of DNA molecules may generate a super liquid-crystalline structure (BR-phase), charachterized by a soliton lattice of the spatial distribution of theorder parameter. The BR-phase could have a layered spatial structure andan abnormal o...
Experimental and theoretical studies of light coupling to various magnetic nanostructured media and nanocomposites are briefly reported. Enhancement of the magneto-optical response is shown to occur when the constitutive materials of photonic crystals are magnetic. Transmission and reflection types of 1D magnetophotonic crystals (MPCs) have been studied. New possibility to enhance the magneto-o...
Dynamic texture is an extension of texture to the temporal domain. Recently, a powerful method for dynamic texture recognition based on volume local binary patterns (VLBP) was proposed. In this paper, we investigate improvements of the original VLBP operator. A proof on the relation of the two rotation invariant VLBP patterns is given. Methods for obtaining rotation invariance are experimentall...
Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ...
Wilson and Cannan studied the interconversion of glutamic acid and pyrrolidonecarboxylic acid in detail by means of changes in amino nitrogen (l), and the system so characterized was utilized by Olcott for the development of a method for the determination of glutamic acid (2). In neither case, however, were temperatures above 125” studied. We have found that glutamic acid can be converted much ...
Two new sesterterpenoids, 1 and 2, were isolated from the sponge Luffariella variabilis. Their planar structures were characterized with spectroscopic analyses. The sole chiral center of compound 1 was elucidated as 12R by comparing observed and calculated optical rotation values. The configurations of compound 2 were determined by NMR and electronic circular dichroism (ECD) studies. Furthermor...
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