Materials Literature
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Dimensionality plays a critical role in determining the properties of materials due to, for example, the different ways that electrons interact in three-dimensional, two-dimensional (2D), and one-dimensional (1D) structures.1-5
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPreparation of Narrowly Distributed Stable and Soluble Polyacetylene Block Copolymer NanoparticlesChi Wu, Aizhen Niu, Louis M. Leung, and T. S. LamView Author Information Department of Chemistry The Chinese University of Hong Kong Shatin, N.T., Hong Kong The Open Labor…
Nanotubes of hexagonal boron nitride ( h -BN) have been synthesized by arc discharge between ZrB 2 electrodes in a nitrogen atmosphere. A new morphology of BN nanotubes at their tips, exhibiting a “triangular flag” like shape, was observed by transmission electron microscopy. This morphology suggests the presence of e…
We have studied the isothermal cold crystallization of poly(ether−ether−ketone) (PEEK) by atomic force microscopy, densitometry, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and small- and wide-angle X-ray scattering (SAXS and WAXS). A two-stage process was clearly evidenced. The first s…
Chiral acyclic allylic alcohols 1 have been chemo-, regio-, and diastereoselectively epoxidized to the corresponding epoxy alcohols 2 by catalysis with the achiral manganese(salen) and iron(porphyrin) complexes 3 and 4 and iodosyl benzene as oxygen donor. The threo diastereoselectivities establish that hydrogen bondin…
Spherulitic growth rates for poly(ethylene oxide) and four model, melt-miscible blends were measured over a range of crystallization temperatures. The miscible diluents fall into two classes: those exhibiting relatively weak intermolecular interactions with PEO and those exhibiting strong interactions. Generally, at a…
In supercooled o -terphenyl (OTP), subsets of probe molecules in more mobile environments can be selectively photobleached. The time required for the remaining slower-than-average probes to be redistributed into an equilibrium set of environments has been measured. At T g + 4 K ( T g = 243 K), this exchange time is 6…
Structural and enzymological studies have shown the importance of Glu144 and Glu164 for the catalysis by 2-enoyl-CoA hydratase-1 (crotonase). Here we report about the enzymological properties of the Glu144Ala and Glu164Ala variants of rat mitochondrial 2-enoyl-CoA hydratase-1. Size-exclusion chromatography and CD spec…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganic Materials Challenges for 193 nm ImagingElsa Reichmanis, Omkaram Nalamasu, and Frank M. HoulihanView Author Information Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974 Cite this: Acc. Chem. Res. 1999, 32, 8, 659–667Publicatio…
The preparation of discrete erbium-doped silicon nanoparticles prepared by the co-pyrolysis of disilane and the volatile complex Er(tmhd) 3 (tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionato) is described. The nanoparticles were characterized by transmission electron microscopy, selected area electron diffraction, X-ray d…
A general approach to prepare nanodispersions of noble metals in organically modified silicates is presented with particular emphasis on the synthesis of gold nanodispersion and its characterization. Organically modified sol−gel monomers containing amine functional groups are used to stabilize the metal salts before t…
We present a detailed calculation of the magnetic couplings between nearest-neighbor and next-nearest-neighbor coppers in the edge-sharing geometry, ubiquitous in many cuprates. In this geometry, the interaction between nearest neighbor coppers is mediated via two oxygens, and the Cu-O-Cu angle is close to 90 degrees.…
The new results are presented of the experimental study of KNbO3 and KTaO3 by means of X-ray photoelectron spectroscopy, soft X-ray emission and X-ray fluorescence spectroscopy. In particular, Nb M(4,5) spectra have been measured over a range of near-threshold excitation energies 206.5 - 240.6 eV, and Ta N(3) spectra…
The equilibrium ground-state structure of LiNbO3 in the paraelectric and ferroelectric phases is fully optimized in a first-principles calculation using the full-potential linearized augmented plane wave method. The equilibrium volume, c/a ratio and all (four, in the ferroelectric phase) internal parameters are found…
The synthesis of highly ordered macroporous materials has been accomplished in a straightforward, single-step reaction. Inorganic frameworks composed of oxides of Si, Ti, Zr, Al, W, Fe, Sb, and a Zr/Y mixture were formed from metal alkoxide precursors templated around polystyrene (latex) spheres. Monodisperse latex sp…
Photoinduced trans−cis−trans isomerization, optical storage, and surface relief gratings are demonstrated in mixed Langmuir−Blodgett (LB) films of poly[4‘-[[2-(methacryloyloxy)ethyl]ethylamino]-2-chloro-4-nitroazobenzene] (HPDR13) and cadmium stearate (CdSt). The trans−cis−trans photoisomerization of the azobenzene ch…
The structures and vibrational spectra of tetrathiafulvalene (TTF), TTF- d 4, and their radical cations have been extensively studied using the projector augmented wave method, which allows first-principles molecular dynamics based on the density functional theory. The dependence of the bond lengths and vibrational fr…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis of Passivating, Nylon-Like Coatings through Cross-Linking of Ultrathin Polyelectrolyte FilmsJeremy J. Harris, Paul M. DeRose, and Merlin L. BrueningView Author Information Department of Chemistry, Michigan State University East Lansing, Michigan 48824 Cite th…
This paper describes the stoichiometry, kinetics, and electronic resistivity of dilute graphite−sulfates intercalation compounds (stages pristine toVIII) obtained during electrochemical oxidation of graphite in 4M H 2 SO 4 solution. The stoichiometry of the reaction was determined by the use of cyclic voltammetry and…
Side-chain liquid-crystalline copolymers (SCLCPs) were synthesized from the alternating copolymerization of maleic anhydride with mesogenic 1-olefins. These SCLCPs showed high glass transition temperatures and highly ordered smectic mesophases. The mesophase width increased with spacer length. The terminal alkyl group…