نتایج جستجو برای: chirality

تعداد نتایج: 12872  

Journal: :Advanced materials 2013
Ventsislav K Valev Jeremy J Baumberg Concita Sibilia Thierry Verbiest

Strong chiroptical effects recently reported result from the interaction of light with chiral plasmonic nanostructures. Such nanostructures can be used to enhance the chiroptical response of chiral molecules and could also significantly increase the enantiomeric excess of direct asymmetric synthesis and catalysis. Moreover, in optical metamaterials, chirality leads to negative refractive index ...

Journal: :Journal of the American Chemical Society 2003
Richard A van Delden Nina P M Huck Jacob J Piet John M Warman Stefan C J Meskers Harry P J M Dekkers Ben L Feringa

The photochemical control of ground- and excited-state chirality of (M)-cis-(1) and (P)-trans-(2)-2-nitro-7-(dimethylamino)-9-(2',3'-dihydro-1'H-naphtho[2,1-b]-thiopyran-1'-ylidene)-9H-thioxanthene is described. It is shown that while ground state chirality can be controlled photochemically by irradiation with light of different wavelengths, the excited state chirality can be tuned either photo...

Journal: :Small 2013
Bilu Liu Hua Jiang Arkady V Krasheninnikov Albert G Nasibulin Wencai Ren Chang Liu Esko I Kauppinen Hui-Ming Cheng

Electronic characteristics of a single-walled carbon nanotube (SWCNT) strongly depend on minor variations in its atomic arrangement, specifically chirality. Therefore, precise control over nanotube chirality is highly desired for their application. Theoretically, SWCNTs with different structures have different chemical reactivities, which can be further used for their chirality selection. Here,...

2009
Sanjiv Kumar Tiwari Jayant Joshi Sanjay Gosain P. Venkatakrishnan

We have studied the evolution of magnetic helicity and chirality in an active region over three consecutive solar rotations. The region when it first appeared was named NOAA10923 and in subsequent rotations it was numbered NOAA 10930, 10935 and 10941. We compare the chirality of these regions at photospheric, chromospheric and coronal heights. The observations used for photospheric and chromosp...

2002
Martin Greiter M. Greiter

We introduce a novel kind of spin liquid, the spin 1 chirality liquid, which provides a generic paradigm for a disordered spin 1 antiferromagnet in two dimensions. It supports spinon and holon excitations, which carry a chirality quantum number. These excitations obey half-fermi statistics. The sign of the statistical parameter is determined by the chirality. The spin 1 chirality liquid is the ...

2016
Yohei Yomogida Takeshi Tanaka Minfang Zhang Masako Yudasaka Xiaojun Wei Hiromichi Kataura

Single-chirality, single-wall carbon nanotubes are desired due to their inherent physical properties and performance characteristics. Here, we demonstrate a chromatographic separation method based on a newly discovered chirality-selective affinity between carbon nanotubes and a gel containing a mixture of the surfactants. In this system, two different selectivities are found: chiral-angle selec...

2003
R. Berardi M. Cecchini

We study the relation between the chirality of a discotic mesogen and that of the chiral columnar aggregates that they can spontaneously form by self– assembly. We discuss first the different types of chiral columns that can be in principle obtained. We introduce then a simple two–site Gay–Berne dissymmetric molecular model where chirality can be easily varied and perform extensive NPT Monte Ca...

Journal: :Particle & Particle Systems Characterization 2019

Journal: :Soft matter 2016
Hale Ocak Marco Poppe Belkız Bilgin-Eran Gürkan Karanlık Marko Prehm Carsten Tschierske

A bent-core compound derived from a 4-cyanoresorcinol core unit with two terephthalate based rod-like wings and carrying chiral 3,7-dimethyloctyloxy side chains has been synthesized in racemic and enantiomerically pure form and characterized by polarizing microscopy, differential scanning calorimetry, X-ray diffraction and electro-optical investigations to study the influence of molecular chira...

Journal: :Physical review letters 2004
M Polcik F Allegretti D I Sayago G Nisbet C L A Lamont D P Woodruff

The results of experimental measurements and theoretical simulations of circular dichroism in the angular dependence (CDAD) of photoemission from atomic core levels of each of the enantiomers of a chiral molecule, alanine, adsorbed on Cu(110) are presented. Measurements in, and out of, substrate mirror planes distinguish CDAD due to the chirality of the sample and the experimental geometry. The...

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