Materials Literature
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Abstract Because of its low chemical reactivity Si 3 N 4 has hardly been used as a starting material for the preparation of multinary silicon nitrides or nitridosilicates, but has gained increasing importance as a nonoxidic material for high‐performance applications. A novel synthetic approach is presented, which star…
Lipase-catalyzed ring-opening bulk polymerizations of ω-pentadecalactone (PDL) were investigated. Screening of selected commercial lipases as catalysts for PDL polymerization at 80 °C was carried out. The results of this work showed that polymerizations catalyzed by lipases PS-30, AK, Lipozyme-IM and Novozym-435 gave…
The miscibility and crystallization behavior of poly(β-hydroxybutyrate) (PHB) and poly( p -vinylphenol) (PVPh) blends were studied by differential scanning calorimetry and optical microscopy (OM). The blends exhibit a single composition-dependent glass transition temperature, characteristic of miscible systems. A depr…
The ubiquitous redox cofactors nicotinamide adenine dinucleotides [NAD and NADP] are very similar molecules, despite their participation in substantially different biochemical processes. NADP differs from NAD in only the presence of an additional phosphate group esterified to the 2'-hydroxyl group of the ribose at the…
Abnormal grain growth (AGG) is not one of the intrinsic properties of alumina but rather is an extrinsic property that is controlled by certain impurities that are introduced during powder synthesis, processing, or sintering. When small amounts of glass‐forming impurities are introduced, some portion beyond their solu…
In this article we examine the structural, electrical, and optical properties of several ternary alloy thin films. The alloys are zinc oxide and cadmium oxide, each of which was reacted with both indium oxide and tin oxide to form sputtering targets. The films were deposited by rf sputtering. X-ray diffraction spectro…
Biologists often gain structural and functional insights into a protein sequence by constructing a multiple alignment model of the family. Here a program called Probe fully automates this process of model construction starting from a single sequence. Central to this program is a powerful new method to locate and align…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Combinatorial Approach for Polymer DesignStephen Brocchini, Kenneth James, Varawut Tangpasuthadol, and Joachim KohnView Author Information Department of Chemistry Rutgers, The State University of New Jersey New Brunswick, New Jersey 09803 Cite this: J. Am. Chem. Soc.…
Bimetallic, oxalate-bridged compounds with bi- and trivalent transition metals comprise a class of layered materials which express a large variety in their molecular-based magnetic behavior. Because of this, the availability of the corresponding single-crystal structural data is essential to the successful interpretat…
Illumination of polyoxotungstates generates a short-lived excited state which decays to form the reactive intermediate wO that is responsible for subsequent transformation of organic substrates. It is shown by laser flash photolysis that wO is formed with a quantum yield of 0.6 and that it survives for ca. 55 ns in de…
About 8 years ago, Brinker and Robinson [l] invented the first aliphatic polybenzimidazoles. Two years later, aromatic polybenzimidazoles with impressive thermal properties were synthesized by Vogel and Marvel [2, 3] at the University of Illinois and later at Du Pont. Since then, high performance polybenzimidazoles re…
ac electrical measurements are reported for the paraelectric phases of the ferroelectric CuInP2S6 and antiferroelectric CuCrP2S6. A complex permittivity analysis confirms previous dielectric results for CuInP2S6. Arrhenius behaviors with nearly identical activation energies were observed for the dc conductivities and…
In electrical insulation in high voltage equipment being serviced under dc stress, space charge is often present. This change greatly influences the electrical field. Quantitative knowledge about the presence of space charge is therefore needed. This paper describes the quest for useful measurement principles. One mea…
The electrochemical behavior of 55% Al-Zn coated steel sheet, on which a very thin polymeric film (≈ 1 μm) was applied, was studied using electrochemical impedance spectroscopy (EIS). Use of a straightforward electric model to analyze the spectra obtained with different polymer films allowed correlation of the coating…
The structure of the alkaline earth silicate glass CaSiO 3 has been investigated using a two-dimensional 29 Si NMR experiment that correlates the isotropic magic-angle-spinning (MAS) spectrum with an anisotropic off-magic-angle-spinning spectrum. Although the one-dimensional magic-angle-spinning (MAS) spectrum is comp…
Femtosecond measurements of transient absorption, bleach, and stimulated emission are used to study the excited-state dynamics of phthalocyanine tetrasulfonate (PcS 4 ) and zinc phthalocyanine tetrasulfonate (ZnPcS 4 ) in solution. In water the excited-state decay process is fast and dominated by energy relaxation due…
A series of layered magnesium organosilicate nanocomposites that contain covalently linked organic functionalities have been prepared by a one-step, direct synthesis procedure. The in situ reactivity of organic moieties (e.g., phenyl, thiol) within the layered inorganic−organic nanocomposites, as well as the potential…
Blends of synthetic atactic poly(3-hydroxybutyrate) (a-PHB) with a natural bacterial isotactic copolymer of 3-hydroxybutyrate with 3-hydroxyvalerate (PHBV) containing 10 mol % of 3HV units were prepared using a simple casting procedure. In the range of compositions explored (10−50% a-PHB), blends of bacterial PHBV and…
The phenomenological boundary conditions for the envelope wave function, which is applicable for contacts of semiconductors with the rather different crystal symmetry are proposed. It is shown that the boundary conditions are determined by the number of real values, which are independent of the electron energy. The nu…
A simple model of polymeric relaxation, associated with the electrochemical switching of polypyrrole films between their reduced (insulating) and oxidized (electronically conducting) states, offers a reasonably precise description of the form of chronoamperograms obtained after previous subjection of the polymer film…