Materials Literature
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Radiococcaceae (Chlorophyta) is a large and widespread family in terrestrial and freshwater habitats. The taxonomy of this family is difficult because no coherent system of generic criteria exists, fact which led to many species transfers from one genus to another with as a consequence many synonyms. Based on traditio…
To understand the exceptionally long fluorescence lifetime of fourfold coordinated CrIV in γ0 Li2MgSiO4 orthosilicate, the structure of this matrix has been refined from neutron diffraction data. Here we also report the crystal growth of Cr:Li2MgSiO4 (low temperature form) by a flux method, and the results of EXAFS an…
Mineral zircon has been considered as a possible medium for luminescence dating. The development of a suitable material for luminescence dating requires detailed knowledge of the processes taking place during, for example, exposure to ionizing radiation, long-term storage, annealing at moderate temperatures, excitatio…
The way in which alignment of hexagonal columnar mesophases depends on molecular structure, film thickness, and surface interactions is investigated. Homeotropic orientation of tapered nonpolymeric and polymeric amphiphilic columnar molecules occurs most readily on carbon substrates. The planar alignment of asymmetric…
Author: Du, K. et al.; Genre: Journal Article; Published in Print: 2002-03; Keywords: MPI für Metallforschung; Abt. Rühle; ZWE Hochspannungs-Mikroskopie; high-resolution transmission electron microscopy; distortion analysis; Title: Lattice distortion analysis directly from high resolution transmission electron microsc…
The reaction of tetracyanoethylene (TCNE) and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) with Fe(CO)(5) leads to formation of magnetically ordered materials of Fe[TCNE](2) (T(c) = 100 K) and Fe[TCNQ](2) (T(c) = 35 K) composition, respectively. In contrast, the reaction with 1,2-dichloro-5,6-dicyanobenzoquinone (DDQ) l…
Evaporation rates of water and oil from creamed oil-in-water emulsions have been measured under conditions of controlled gas flow. The continuous water phases of the emulsions evaporate at rates equal to that for pure water under the same conditions. The evaporation rates of dispersed oil drops are retarded, relative…
The existence of ether byproducts could be clearly proven for the hyperbranched polymerization of 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) using NMR spectroscopy. Polymerization experiments were performed under standard conditions with different catalysts. The ether structures were identified by characteristic 1…
The structures of hydrogen silsesquioxane based porous low dielectric constant (low- k ) films (XLK) prepared with varying process conditions are characterized using a combination of high-energy ion scattering, X-ray reflectivity, and small-angle neutron scattering. We measure the film thickness, average mass density,…
Abstract The synthesis of second‐generation (G‐2) dendritic polymers of isoprene (I) and styrene (S) was achieved with anionic polymerization high‐vacuum techniques and by performing the following steps: (1) selective reaction of a living chain with the chlorosilane group of 4‐(chlorodimethylsilyl)styrene (a dual‐func…
We report high-resolution specific-heat measurements on the quasi-two-dimensional organic superconductor $\ensuremath{\kappa}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}\mathrm{Cu}(\mathrm{NCS}{)}_{2},$ performed by using a sensitive ac-modulation technique. The main observations are (i) a discontinui…
Highly ( S )-enriched substituted poly(ε-caprolactone)s were synthesized from 4-methyl-ε-caprolactone (4-MeCL) and 4-ethyl-ε-caprolactone (4-EtCL) by lipase Novozym-435 (from Candida antarctica ) catalyzed ring-opening polymerizations. The polymerizations were performed in bulk, thus eliminating the need for solvents…
We report the control of molecular orientation in solid films through self-organization and induced-orientation processes. We synthesized water-soluble cationic 3,4,9,10-perylene diimide ( 1 ) and studied its self-organization in aqueous solution. By UV−vis spectroscopy, H-aggregates of 1 were observed forming in solu…
The synthesis of highly ordered cubic mesoporous silica MCM-48 with tunable pore sizes in the range 1.6−3.8 nm is reported. Pore size control has been achieved by using (mixtures of) gemini surfactants, [CH 3 (CH 2 ) n NMe 2 (CH 2 ) m NMe 2 (CH 2 ) n CH 3 ] 2+ 2Br -, of different average chain length ( m = 12 and n =…
Diamond is a wide-band-gap material with large donor and acceptor ionization energies. In principle, at room temperature and below, the Fermi energy is pinned close to the donor or acceptor level, depending on which is present in the higher concentration. In semiconductors with shallow donors and acceptors the equilib…
Abstract Conductive polymer composites possessing a low percolation‐threshold concentration as a result of double percolation of a conductive filler and its host phase in an immiscible polymer blend afford a desirable alternative to conventional composites. In this work, blends of high‐density polyethylene (HDPE) and…
We report the formation of novel self-assembled ultrathin (ca. 20 nm) films comprising in-plane arrays of nanoscale surface cavities. The original micellar thin films, formed by casting kinetically stable reverse micelles from a solution of a styrene (PS)−acrylic acid (PAA) diblock copolymer in toluene onto silicon ni…
We have measured the differential conductance of individual multiwall carbon nanotubes. Coulomb blockade and energy level quantization are observed. The electron levels are nearly fourfold degenerate (including spin) and their evolution in magnetic field (Zeeman splitting) agrees with a g factor of 2. In zero magnetic…
We present a systematic analysis of the effect of radial deformation on the atomic and electronic structure of zigzag and armchair single wall carbon nanotubes using the first-principle plane wave method. The nanotubes were deformed by applying a radial strain, which distorts the circular cross section to an elliptica…
We have performed first principles electronic structure calculations to investigate the structural and magnetic properties of Fe/ZnSe(001) interfaces. Calculations involving full geometry optimizations have been carried out for a broad range of thickness of Fe layers(0.5 monolayer to 10 monolayers) on top of a ZnSe(00…