Materials Literature
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The surface morphology of thin molten films of phase separating mixtures of poly(ethylenepropylene) (PEP) and perdeuterated poly(ethylenepropylene) (dPEP) of the critical composition were investigated using scanning force microscopy. Volume fraction versus depth profiles were also obtained using time-of-flight forward…
The synthesis of a new class of poly(aryl ether chalcone)s is described by a polycondensation reaction of 4,4‘-difluorochalcone with various bisphenols in the excess anhydrous potassium carbonate in sulfolane/toluene mixture solvent. Fluoride atoms located at the para position of the chalcone moiety were found to be v…
Edible films, coatings and biodegradable packagings produced from biological materials offer numerous advantages over other conventional synthetic packaging materials. Potential applications of edible films are numerous (internal moisture or solute barriers of heterogeneous foods, individual protection of food pieces,…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTChanging Cellulose Crystalline Structure in Forming Wood Cell WallsYutaka Kataoka and Tetsuo KondoView Author Information Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba Norin, 305 JapanCite this: Macromolecule…
This paper examines the properties of a defected zeolite matrix with the faujasite structure, promoted with gallium oxide. The fate of β-Ga 2 O 3 loaded onto ultrastable faujasite is followed by XRD, FT IR, and laser Raman spectroscopies, and also by solid-state multinuclear NMR. Gallium(III) oxide is reduced after th…
Deprotonation of p-hydroxybenzoate to the phenolate and reprotonation of the hydroxylated dienone intermediate to form the product are essential steps in the reaction catalyzed by p-hydroxybenzoate hydroxylase (PHBH). The mechanism by which protons are transferred in these reactions is not obvious, because the substra…
Direct evidence of local structural inhomogeneity and nonuniform doping-level distribution in conducting polymer film has been obtained using Kelvin probe force microscopy (KFM) and atomic force microscopy (AFM). The KFM data suggests that the polymer consists of grains that constantly differ in work function and thus…
Polarized Fourier transform infrared microscopy (FT-IRM) was used to assess the orientation of mineral and matrix components of the normally calcified turkey leg tendon. Two groups of tendon, < 16 weeks of age (young) and > 60 weeks of age (old), were analyzed. Linear sequences from calcified, non-calcified, and trans…
Abstract Poly(aryl ether ketone ketone)s (PEKKs) are prepared via a Friedel‐Crafts acylation reaction with diphenyl ether and terephthalic acid (T) and/or isophthalic acid (I). The crystal structure, polymorphism and morphology of three PEKK homopolymers have been investigated using transmission electron microscopy (T…
Molecular geometries, dipole moments, polarizabilities and first-order hyperpolarizabilities for five classic donor−aromatic π system−acceptor NLO chromophores were calculated, using semiempirical methods (PM3), in both vacuum and solvent environments. Solvent effects on the computed molecular geometries were found to…
We present results of the energies of formation and hydration of small clusters and rings containing Si and Al; the results provide a rationalisation of Lowenstein's rule in terms of the energetics of species containing Al–O–Al bridges.
A homogeneous catalytic system based on a suitable Ni(II) diimine derivative and methylaluminoxane affords predominantly syndiotactic polypropylene at subambient temperatures. The polymer microstructure is that expected for a “chain-end” mechanism of steric control. NMR analysis of polymer samples carrying selectively…
The luminescence properties of Bi3+, Eu3+, Dy3+ and energy transfer from Bi3+ to Dy3+ and Eu3+ have been studied in two modifications of Y2SiO5(low-temperature X1 type and high-temperature X2 type) and discussed in relation to their crystal structures. The Bi3+ ion luminesces in the blue region of the spectrum in X1-Y…
Beryllium oxide(BeO)-doped (0.3, 0.6, 0.9, 1.2 and 13.6 wt%) UO2 pellets were fabricated to evaluate the effects of BeO precipitate shape on thermal conductivity. Precipitate distributions were of two types: BeO precipitated almost continuously along a grain boundary (designated BeO continuous type) and spherical BeO…
A heterogeneous reactor model was developed describing kinetic experiments on the heterogeneously catalyzed oxidative coupling of methane in a laboratory fixed-bed reactor. The catalyst produces radicals which react further through gas-phase reactions in the pores of the catalyst and in the interstitial phase. The rea…
Application of thermosensitive polymers as an embolic material for intravascular neurosurgery was investigated. We intended to use thermosensitive polymers to occlude vessels by precipitation in response to body temperature. Copolymers of N-isopropylacrylamide (NIPAM) and N-n-propylacrylamide (NPAM) were selected as t…
Ultrapure poly(vinyl alcohol) (PVA) hydrogels were prepared by exposing an aqueous solution of 15 or 20 wt% PVA to repeated cycles of freezing for 6 or 12 h at -20 degrees C and thawing for 2 hours at 25 degrees C. The adhesive characteristics of the PVA gels in contact with a reconstituted mucus surface were quantifi…
This paper presents a study of the effect of important fabric mechanical properties on drape. The study uses a mathematical modeling technique to simulate fabric drape. Young's modulus in the warp and weft directions, shear modulus, Poisson's ratio, and fabric thickness are the parameters studied in this work. Results…
Two new water soluble squaraine dyes, bis[3-( p -carboxybenzyl)benzothiazol-2-ylidene]squaraine (Sq1) and bis[3-(carboxymethyl)benzothiazol-2-ylidene]squaraine (Sq2), have been synthesized and their photophysical properties have been characterized. Sq1 and Sq2 form dimer aggregates in water that have absorption bands…
The interaction of ATP with the active site of hexokinase is unknown since the crystal structure of the hexokinase-ATP complex is unavailable. It was found that the ATP binding site of brain hexokinase is homologous to that of actin, heat shock protein hsc70, and glycerol kinase. On the basis of these similarities, th…