Materials Literature
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The evolution of the dielectric α relaxation and ionic conductivity with time t r during polymerization at 60 °C of mixtures of the diepoxide DGEBA, the diamine PACM, and the diluent Decalin (DEC) or di- n -butyl phthalate (DBP) has been studied using real-time dielectric relaxation spectroscopy (DRS). Data are presen…
Reaction of organocobalt(III) porphyrins with a cobalt(II) complex of a distinguishable porphyrin or tetrapyrrole resulted in the reversible exchange of the organic axial ligand. The exchange reaction was facile in such solvents as benzene, toluene, dichloromethane, chloroform, and pyridine; was unaffected by total ex…
The previously unknown crystal structure of the C(1) subunit of the carotenoid-binding protein alpha-crustacyanin has been determined using the anomalous scattering available at 1.77 A wavelength to determine the partial structure of the S atoms intrinsic to the native protein. The resulting 'heavy-atom' phases, in co…
The synthesis of poly(vinyl hydroquinone), PVHQ, via stable free radical polymerization (SFRP) to give a low-dispersity (1.5) material is described. The electrochemical properties of the resulting material deposited as films onto glassy carbon electrodes have been investigated by cyclic voltammetry. In aqueous acetic…
A first-principles molecular dynamics study of glassy ${\mathrm{As}}_{2}{\mathrm{Se}}_{3}$ and ${\mathrm{As}}_{4}{\mathrm{Se}}_{4}$ is presented. We focus on the differences in local structure between these glasses and identify the structural elements of ${\mathrm{As}}_{4}{\mathrm{Se}}_{4}$ and present a model of the…
A series of π-conjugated rodlike polymers, poly(2,5-dialkyl p -phenyleneethynylene)s, PPE's, were synthesized with alkyl groups of n -butyl ( 4a ), n -octyl ( 4b ), n -tetradecyl ( 4c ), 2-ethylhexyl ( 4d ), and 2-cyclohexylethyl ( 4e ). Polymers with linear alkyl side groups ( 4a, 4b, and 4c ) formed gels in toluene…
The coordination environments of Ge and As atoms in ${\mathrm{Ge}}_{x}{\mathrm{As}}_{y}{\mathrm{S}}_{1\ensuremath{-}x\ensuremath{-}y}$ glasses with $x:y=1:2,$ 1:1, and 2.5:1 and with wide-ranging S contents have been studied with Ge and As K-edge x-ray absorption fine structure spectroscopy. The coordination numbers o…
Using ab initio pseudopotential plane wave method and generalized gradient approximation for the exchange and correlation energy, we report the finding of high spin ground state of ${\mathrm{Al}}_{12}\mathrm{Cu}$ cluster in accordance with the Hund's rule of maximum spin at half-filling. It has perfect icosahedral sym…
Abstract The rheological properties, morphology, and oil resistance in natural rubber and nitrile‐butadiene rubber (NR/NBR) blends are investigated as functions of the blending conditions. It is found that the Mooney viscosity of the blends depends more strongly on the blending time than the rotor speed. The size of t…
The polarization modulation infrared reflection−absorption spectroscopy (PM-IRRAS) technique has been used in situ to determine the orientation and molecular structure of an equimolar mixture of poly( l -lactide) (PLLA) and poly( d -lactide) (PDLA) spread at the air−water interface. The characteristics of the compress…
Plasma reforming and coupling of methane with carbon dioxide using a point-to-point type of reactor have been invested. A feed mixture of CH 4 and CO 2 could be converted mainly to CO, H 2, and C 2 H 2 at atmospheric pressure and without external heating except plasma heating. Under a condition of 200 mL/min of CH 4 a…
Nanocrystalline powders of ceria doped with 20 at. % of various rare-earth cations (Ce 0.8 RE 0.2 O 1.9, RE = La, Nd, Sm, Gd, Dy, Y, Ho, Er, and Yb) have been synthesized via coprecipitation using ammonium carbonate as the precipitant. The precursors and the resultant oxide powders were characterized by chemical analy…
We describe the evolution of the static and dynamic spin correlations of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ for $x=0.1,$ 0.125, and 0.2, where the system evolves from the canted magnetic state towards the insulating ferromagnetic state, approaching the metallic transition $(x=0.22).$…
Chemically capped CdS nanoparticles are embedded in porous silicon (PS) by a dip coating method. Atomic force microscopy measurements reveal that the PS surface is covered with CdS nanoparticles forming well-defined rectangular blocks of nearly uniform size (200 × 200 nm 2 ). Photoelectron spectroscopy and energy disp…
Abstract The influence of the degree of crystallinity and the syndiotacticity on the 1145, 1095, and 916 cm −1 bands was studied. The intensity of the 1145 cm −1 band increased with increasing syndiotacticity at a low degree of crystallinity and with an increasing degree of crystallinity for a sample with syndiotactic…
An attempt has been made to show the difference in the penetrability of coconut oil and mineral oil in human hair. We have used secondary ion mass spectrometry (SIMS) in combination with a time-of-flight (TOF) mass spectrometer. Characteristic ions formed by the pure components when bombarded with gallium ions have be…
The synthesis and living cationic ring-opening polymerization of 2-[3,4-bis(n-alkan-1-yloxy)phenyl]-2-oxazolines with alkan being tetradecan and pentadecan, i.e., (3,4)nG1-Oxz with n = 14 and 15, is described. The structural analysis of the resulting polymers with well-defined molecular weights and narrow molecular we…
Acellular polyanionic collagen materials intended for biomaterial and tissue engineering uses were prepared by the selective and controlled hydrolysis of carboxyamides from asparagine and glutamine residues of type I collagen present in pericardium, tendon, and intestinal submucosa, all from bovine origin. The increas…
We report the results of thermoelectric power (TEP) of a Cr doped ${\mathrm{La}}_{0.5}{\mathrm{Pb}}_{0.5}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Cr}}_{x}{\mathrm{O}}_{3}$ $(x=0--0.45)$ system measured both in the presence and the absence of magnetic field $(B=1.5\mathrm{T}).$ The small field dependence of the Seebeck…
A hitherto unknown copolymer that contains sulfur in the backbone linking 3-hydroxybutyrate and 3-mercaptobutyrate by thioester linkages, poly(3HB-co-3MB), was synthesized by the polyhydroxyalkanoate-(PHA-) accumulating bacterium Ralstonia eutropha, when 3-mercaptobutyric acid was fed as the carbon source in addition…