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Edge-on Orientation (edge-on + orientation)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

High Electron Mobility and Ambient Stability in Solution-Processed Perylene-Based Organic Field-Effect Transistors

ADVANCED MATERIALS, Issue 16 2009
Claudia Piliego
Bottom-contact n-channel OFETs based on spin-coated films of N,N, -1H,1H -perfluorobutyl dicyanoperylenediimide (PDI-FCN2) exhibit a saturation-regime mobility of 0.15,cm2 V,1 s,1 in vacuum and good air stability. These performances are attributed to the high crystallinity and to the edge-on orientation promoted by the thermal treatment, as showed by confocal laser microscopy. [source]

Axisymmetric orbit models of N -body merger remnants: a dependency of reconstructed mass on viewing angle

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007
J. Thomas
ABSTRACT We model mock observations of collisionless N -body disc,disc mergers with the same axisymmetric orbit superposition program that has been used to model elliptical galaxies in Coma. The remnants sample representatively the shape distribution of disc,disc mergers, including the most extreme cases, like highly prolate, maximally triaxial and dominantly oblate objects. The aim of our study is to better understand how the assumption of axial symmetry affects reconstructed masses and stellar motions of systems which are intrinsically not axisymmetric, whether the axisymmetry assumption then leads to a bias and how such a potential bias can be recognized in models of real galaxies. The mass recovery at the half-light radius depends on viewing angle and intrinsic shape: edge-on views allow to reconstruct total masses with an accuracy between 20 per cent (triaxial/prolate remnants) and 3 per cent (oblate remnant). Masses of highly flattened, face-on systems are underestimated by up to 50 per cent. Deviations in local mass densities can be larger where remnants are strongly triaxial or prolate. Luminous mass-to-light ratios are sensitive to box orbits in the remnants. Box orbits cause the central value of the Gauss,Hermite parameter H4 to vary with viewing angle. Reconstructed luminous mass-to-light ratios, as well as reconstructed central masses, follow this variation. Luminous mass-to-light ratios are always underestimated (up to a factor of 2.5). Respective dark haloes in the models can be overestimated by about the same amount, depending again on viewing angle. Reconstructed velocity anisotropies , depend on viewing angle as well as on the orbital composition of the remnant and are mostly accurate to about ,,= 0.2. Larger deviations can occur towards the centre or the outer regions, respectively. We construct N -body realizations of the Schwarzschild models to discuss chaotic orbits and the virial equilibrium in our models. In this study we explore the extreme limits of axisymmetric models. Apparently flattened, rotating ellipticals of intermediate mass are likely close to both, axial symmetry and edge-on orientation. Our results imply that Schwarzschild models allow a reconstruction of their masses and stellar anisotropies with high accuracy. [source]

Surface-enhanced Raman difference between bombesin and its modified analogues on the colloidal and electrochemically roughen silver surfaces

BIOPOLYMERS, Issue 10 2008
Edyta Podstawka
Abstract In this article, surface-enhanced Raman scattering (SERS) spectra of bombesin (BN) and its six modified analogues ([D-Phe12]BN, [Tyr4]BN, [Tyr4,D-Phe12]BN, [D-Phe12,Leu14]BN, [Leu13 -®-Leu14]BN, and [Lys3]BN) on a colloidal silver surface are reported and compared with SERS spectra of these species immobilized onto an ellectrochemically roughen silver electrode. Changes in enhancement and wavenumber of proper bands upon adsorption on different silver surfaces are consistent with BN and its analogues adsorption primarily through Trp8. Slightly different adsorption states of these molecules are observed depending upon natural amino acids substitution. For example, the indole ring in all the peptides interacts with silver nanoparticles in a edge-on orientation. It is additionally coordinated to the silver through the N1H bond for all the peptides, except [Phe12]BN. This is in contrary to the results obtained for the silver roughen electrode that show direct but not strong N1H/Ag interaction for all peptides except [D-Phe12,Leu14]BN and [Leu13 -®-Leu14]BN. For BN only CO is not involved in the chemical coordination with the colloidal surface. [Lys3]BN and BN also adsorb with the CN bond of NH2 group normal and horizontal, respectively, to the colloidal surface, whereas CNH2 in other peptides is tilted to this surface. Also, the Trp8 CH2 moiety of only [Tyr4]BN, [Lys3]BN, and [Tyr4,D-Phe12]BN coordinates to Ag, whereas the Phe12 ring of [Phe12]BN, [Tyr4,D-Phe12]BN, and [D-Phe12,Leu14]BN assists in the peptides binding only on the colloidal silver. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 807,819, 2008. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]

Two-Dimensional Self-Assembly of a Porphyrin,Polypyridyl Ruthenium(II) Hybrid on HOPG Surface through Metal,Ligand Interactions

CHEMPHYSCHEM, Issue 9 2010
Aimei Gao Dr.
Abstract The synthesis and self-assembly behavior of porphyrin,polypyridyl ruthenium(II) hybrid, which consists of a flexible alkyl chain attached with two conjugated moieties is described. The electronic absorption spectrum and emission spectra show that the [C8 -TPP-(ip)Ru(phen)2](ClO4)2, abbreviated as (C8ip)TPPC has optical properties. Scanning tunneling microscopy (STM) studies found that the ,,, interaction and metal,ligand interaction allow (C8ip)TPPC to form self-assembled structure and have an edge-on orientation on the highly oriented pyrolytic graphite (HOPG) surface. The multidentate structure in (C8ip)TPPC molecules act as linkers between the molecules and form metal,ligand coordination, which forces the assembly process in the direction of stable columnar arrays. In addition, although the sample was stored for two months in ambient conditions, STM experiments showed that the order of (C8ip)TPPC self-assembly only slightly decreased which indicates that the self-assembled monolayer is stable. This work demonstrates that introducing a metal-ligand in the porphyrin-polypyridyl compound is a useful strategy to obtain novel surface assemblies. [source]