Search Results

You are looking at 1 - 10 of 2,138 items :

  • "spectral properties" x
Clear All

2 Spectral properties Basic properties of the spectra of regular graphs, including the Hoffman polynomial, are introduced in Section 2.1. In Section 2.2 we consider certain graph operations (likemaking the complement, the join or the line graph) applied to a regular graph and the spectrum of the resulting graph. Those who study graphs by means of their spectra usually work with different theories based on different matrices associated with graphs. In Section 2.3 we intro- duce the three frequently investigated matrices (precisely, the Laplacian matrix, the

Spectral Properties of Fluorescent Dyes in Lecithin Vesicles Probes for the Structure of Lipid Bilayer Membranes and for Membrane Potentials G. W. Pohl Fachbereich Biologie, Universität Konstanz (Z. Naturforsch. 31c, 575 — 588 [1976] ; received May 10, 1976) Lecithin Vesicles, Fluorescent Probes, Phase Transitions, Membrane Potentials Three fluorescent dyes (a merocyanin, a cyanin and a modified umbelliferon) have been in­ corporated into vesicles from three different lecithins. Their absorption spectrum, emission spectrum and fluorescence polarization in the

466 Z. Kristallogr. 213 (1998) 466-472 © by R. Oldenbourg Verlag, München Crystal structures of aminophenalenones with relation to their spectral properties A. V. Yatsenko*. V. A. Tafeenko, K. A. Paseshnichenko Moscow Stale University, Department of Chemistry, 1 19899 Moscow, Russian Federation T. V. Stalnaya and S. L. Solodar Institute of Organic Intermediates and Dyes. B. Sadovaya 1/4, 103787 Moscow, Russian Federation Received October 28, 1997; accepted February 10. 1998 Abstract. X-ray structural investigations of 9-amino-l/_- phenalen-l-one (C13H9NO), N

0.535 Å and 0.645 Å, respectively (Shannon 1976), and the valence electrons for Al3+ are in p orbitals while those for Fe3+ * E-mail: jbishop@mail.arc.nasa.gov The visible and infrared spectral properties of jarosite and alunite JANICE L. BISHOP1,2,* AND ENVER MURAD3 1SETI Institute, 515 North Whisman Road, Mountain View, California 94043, U.S.A. 2NASA-Ames Research Center, Mail Stop 239-4, Moffett Field, California 94035, U.S.A. 3Bayerisches Geologisches Landesamt, D-95603 Marktredwitz, Germany ABSTRACT The visible and infrared spectral properties of two

DEMONSTRATE MATHEMATICA Vol. XXXVII No 1 2004 Christoph Schmoeger SPECTRAL PROPERTIES OF GENERALIZED INVERSES Abstract. Let A denote a unital complex Banach algebra. An element a E A is said to be relatively regular if aba = a for some b € A. Then b will be called a generalized inverse of a. In this note we study spectral properties of generalized inverses of a. 1. Relatively regular elements Throughout this paper let A denote a complex unital Banach algebra with unit 1. If a 6 A, then cr(a), p(a), and r(a) denote the spectrum, the resolvent set and the

working with nonlinear terms which do not satisfy any monotonicity condition such as those required to perform projections on the so called Nehari manifold as in, for instance, [ 20 , 29 ]. In this purpose, spectral properties of self-adjoint operators are going to be exploited in order to get the geometry of a linking structure and then apply an abstract result to obtain a critical point to the functional associated to the nonlinear equation, namely a solution to the problem. Furthermore, a compactness structure given by Cerami sequences, ( C ) c {(C)_{c}} sequences

Camillo Trapani and Francesco Tschinke Faithfully representable topological *-algebras: some spectral properties Abstract: A faithfully representable topological *-algebra (fr*-algebra) A0 is charac- terized by the fact that it possesses sufficiently many *-representations. Some spec- tral properties are examined, by constructing a convenient quasi *-algebraA overA0, starting from the order bounded elements of A0. Keywords: topological *-algebras; bounded elements MSC: 46K05; 46K10 1 Introduction This note is devoted to a particular family of topological

Synthesis, Structure and Spectral Properties of Pyrylium Salts and Their Derivatives. I. 5,6-Dihydro-benzo(c)xanthylium Salts T. G. Deligeorgiev Department of Chemistry, University of Sofia, Sofia P. Nikolov and N. Tyutyulkov Bulgarian Academy of Sciences, Institute of Organic Chemistry, with Center for Phytochemistry, Sofia Z. Naturforsch. 42 a, 43-48 (1987); received May 2, 1986 The synthesis and spectral properties of a group of xanthylium salts are described. The longest wavelength absorption maximum in organic solvents (ethanol, 1,4-dioxane

An Asymmetric Salen-type Bisoxime Ligand and Its Supramolecular Copper(II) Complex: Synthesis, Crystal Structure and Spectral Properties Wen-Kui Donga, Yin-Xia Suna, Si-Jia Xinga, Yuan Wanga, and Xiong-Hou Gaob a School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, P. R. China b Lanzhou Petrochemical Research Center, PetroChina, Lanzhou 730060, P. R. China Reprint requests to Prof. Wen-Kui Dong. E-mail: dongwk@126.com Z. Naturforsch. 2012, 67b, 197 – 203; received February 17, 2012 A supramolecular Cu(II) complex [CuL(H2O

Abstract

The structural and spectral properties of coumarin derivatives in complex environments were investigated within the time-dependent density functional theory (TD DFT). Absorption spectra calculations were obtained at TD PBE0/6-31+G(d,p) level of theory for coumarin47 in the gas-phase and in various polar and non-polar organic solvents. The geometries of coumarins 6, 30, 47 and 522 in the gas phase and in inclusion complexes with the β-cyclodextrin (βCD) were determined by PM3 and DFT (HCTH/6-31G) calculations. Encapsulation of coumarin in βCD and associated changes in electronic structure produced either a red or blue shift in the absorption spectra of coumarins. A proposed cavity model for βCD-coumarin complex in water solution allowed identification of various contributions to the overall shift in the absorption spectra of coumarin upon complex formation in a solvent environment