Materials Literature
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This paper presents an experimental study of the coordination number of binary packings by the use of the liquid bridge technique and provides detailed information about the distributed coordination numbers corresponding to different types of contacts between small and large components and their dependence on particle…
The reactions of ethanol and 1-propanol on a 1.3 monolayer Co overlayer was investigated in an effort to understand the reactivity of Co thin films deposited on Mo(110). Electron energy loss data show that O−H bond scission to afford the alkoxide occurs by 275 K for both alcohols on a Co monolayer deposited on Mo(110)…
Four generations of a dendrimer with a fluorescent core consisting of a rubicene moiety are synthesized. The biexponential nature of fluorescence decay in toluene indicates the presence of two emitting conformations. Molecular modeling suggests that a conformation where the dendrons interact with the core is not impro…
Radiolysis of aqueous solutions of TNT was examined to provide fundamental information concerning the reactions of TNT with radical species in water. γ-Radiation was used in conjunction with radical scavengers to compare yields for radiation-induced TNT transformation under oxidizing and reducing conditions and in the…
The gas-phase hydrogenation of acetonitrile was studied with silica-supported platinum catalysts of which the degrees of metal dispersion were widely changed by reduction conditions. The activities were found to decrease gradually during the course of reaction for all the catalysts examined. The initial rate of reacti…
Buried channel optical waveguides were fabricated from fluorinated polyimides. They operated in single mode and showed an optical loss of less than 0.3 and 0.7 dB/cm for TE and TM polarizations, respectively, at a wavelength of 1.3 mum. Moreover, these waveguides had high heat and moisture resistance; the optical loss…
A conformational energy model has been set up for poly(ethylene terephthalate) (PET) for use in molecular dynamics simulations. The molecular dimensions, as expressed by the characteristic ratio, and the dipolar correlation factor of PET are key parameters in the simulations because they depend very differently on the…
The formation of iron oxide films and their roles in determining the dry wear properties of low alloy steel couples are described. Essentially, alpha-Fe<SUB>2</SUB>O<SUB>3</SUB>, haematites (Fe<SUB>3</SUB>O<SUB>4</SUB>), wustite (FeO) and oxide mixtures were the predominant compositions found in four regions of mild o…
Lead is one of the poisonous elements for de-NO x catalysts especially in the case of municipal waste incineration plants. Samples of a commercial selective catalytic reduction catalyst were impregnated with different amounts of Pb(NO 3 ) 2, and their catalytic activities were studied. The XPS and SEM analysis showed…
Poly(lactide) is synthesized by ring-opening copolymerization of various combinations of l -lactide, d -lactide, and meso -lactide. The influence of the stereochemical differences of the three lactides on the kinetics of melt copolymerization was determined by monitoring the change in the polymer stereosequence distri…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHemiporphyrazines as Targets for the Preparation of Molecular Materials: Synthesis and Physical PropertiesFernando Fernández-Lázaro, Tomás Torres, Bernd Hauschel, and Michael HanackView Author Information Departamento de Química Orgánica (C-I), Universidad Autónoma de Madrid…
Oxidized and reduced cobalt(II) hexacyanoferrates were fabricated and characterized in the presence of alkali metal (Li +, Na +, K +, Cs + ) and Co 2+ countercations. Formal potentials of hexacyanoferrate(III,II) redox reactions are sensitive to the choice of electrolyte cation, and they correlate well with the sizes…
Classification, nomenclature, and structure representation are presented for dendritic and star polymers in SCION, a DuPont proprietary scientific and technical online database. The problems of registering dendritic and hyperbranched structural repeating units (SRUs) with odd numbers of crossing bonds are described, a…
Reaction of Ag[C3(CN)5] and [MnIIITPP]Cl (TPP = meso-tetraphenylporphinato) leads to [MnIIITPP]+[C3(CN)5]-, which has been crystallographically, spectroscopically, and magnetically characterized.This complex forms a 1-D ···D+A-D+A-··· coordination polymer with [C3(CN)5]- (A) having an unusual μ asymmetric bridge bondi…
Zirconia-based systems have been extensively studied for some 25 years, and a wealth of exciting results has been amassed. This book tracks the progress made in the field; from very early phase stability work, to modern approaches which involve quite sophisticated models for the transformation toughening that is assoc…
In the absence of suitable single crystals, the problem of determining the connectivity pattern of the title compound (and of its phenyl analogue), i.e. that of discriminating between two markedly different stereoisomers, has been solved by the powder diffraction technique. The structure was solved by ab initio XRPD m…
To improve adhesion between polypyrrole and glass, new pyrrole-substituted organotrialkoxysilanes coupling agents are synthesized and studied. Solubility, hydrolysis, and self-condensation features in aqueous solutions are investigated by IR, 1 H, and 29 Si NMR spectroscopies. Varying the experimental conditions of py…
We present first-principles total-energy calculations of (001) surfaces of SrTiO3. Both SrO-terminated and TiO2-terminated surfaces are considered, and the results are compared with previous calculations for BaTiO3 surfaces. The major differences are in the details of the relaxed surface structures. Our calculations a…
Monte Carlo simulations with an effective Hamiltonian parametrized from first principles are performed to study the dielectric response of BaTiO3 as a function of temperature, with particular emphasis on the behavior of the dielectric constant near the transition from the ferroelectric tetragonal phase to the paraelec…
The elastic theory of quasicrystals considers, in addition to the normal displacement field, three phason degrees of freedom. We present an approximative solution for the elastic Green's function of icosahedral quasicrystals, assuming that the coupling between the phonons and phasons is small.