Materials Literature
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Maleic acid(MA) was found to polymerize easily by potassium persulfate (KPS) in water in the presence of polyvinylpyrrolidone (PVP), and to form a polymer complex in which the molar ratio of MA to VP monomer unit was approximately unity. The formation of the polymer complex was accelerated by increases in the reaction…
The cylindrical cell method for determining the refractive indices of liquid crystals is described. This method is based on the use of a cylindrical cell composed of a pair of semi-cylindrical prisms and the measurement of the incident angle dependence of transmitted light intensities. It is applied to the measurement…
Abstract The anodic peak potentials of [2.2]para- and -metaparacyclophanes were found to be highly dependent on the solvent. A cleavage reaction occured when [2.2]paracyclophane was electrolyzed anodically, using acids or alcohols as nucleophilic solvents, whereas lead tetraacetate oxidation in trifluoroacetic acid–di…
To the Editor.— "Whisker hair" is the name that barbers have given to the short, dark, curly hair that grows anterior to, over, and behind the ears in young men. This hair begins to appear in young men at approximately 18 to 25 years of age. It only occurs in individuals who are, or will be, quite bald. It undoubtedly…
Fission fragments anisotropy in fast-neutron-induced fission of 235U was measured at neutron energies ranging from 0.3 to 1.4 MeV at intervals of 0.1, 1.6, 1.8, and 2.2 MeV. In the present study, the pairing energy gap (2Δ0) for the highly deformed transition state of the nucleus 236U was found to be 2.0 ± 0.06 MeV.
The domain memory was first reported by Bobeck (1) in 1967. His concept was based on the fact that a cylindrical magnetic domain, that is, a small region of reversed magnetic polarity in an otherwise com pletely magnetized plate of material, is stable over a convenient range of applied field. The stable cylindrical d…
A simple method is proposed for studying the spectral response of a first-order waveguide grating filter with random fluctuations in the period of the grating. The method can be applied to any grating groove shape, and it can be used to study the effect of both random and systematic variations in other grating filter…
When isotactic polypropylene material was uniaxially cold-drawn and then annealed with free ends, folded-chain lamellar crystals formed almost perpendicular to the c-axis, i.e., to the draw direction. When stress is applied in the draw direction, the forces are primarily transmitted by the taut tie molecules connectin…
Composites made from powder-liquid constituents and subjected to elevated temperatures during storage are more stable than those employing pastes. The decomposition of the benzoyl peroxide ingredient is mainly responsible for the increased setting time and the decreased mechanical properties of the resulting composite.
The luminescence and transport properties of high-quality undoped and phosphorus-doped Zn1-xMgxTe alloys (x ≤ 0.50) have been investigated. At 4.2 and 300 K, the photoluminescence of unintentionally doped crystals is dominated by near-band-edge recombination mechanisms. In phosphorus-doped samples, the luminescence sp…
The pressure (0–10 kbar) and temperature (10–130°C) dependence of the dielectric properties of squaric acid (H 2 C 4 O 4 ) were investigated. From the large isotope effect on the transition temperature of T n d / T n =1.38 (the superscript d stands for deuteration) and the large decrease of T n with pressure of d T n…
K 2 Au 2 l 6 crystallizes in the monoclinic space group P2 1 /n. It is built up by linear anions AUI 2 -, square-planar anions AUI 4 -, and K + cations. The coordination of the gold(I) and gold(III) atoms is completed by additional iodine atoms at larger distances to form compressed and elongated octahedra, respective…
Abstract The γ‐radiation‐induced crosslinking of polystyrene was studied at 30–100°C in vacuo with a dose rate of 6.35 × 10 5 rad/hr. The amount of hydrogen formation increased with increasing irradiation time, and the rate of the formation decreased with the time. The results were well described by the zero‐order for…
Abstract not Available.
Abstract Influence of hydrofuramide and ethanolamines on efficient vulcanization (EV), semi‐EV, and conventional sulfur vulcanization accelerated by tetramethyl thiuram disulfide is reported. In the case of thiuram vulcanization, the amines increase the cure rate but reduce the crosslink density. The interaction of te…
Abstract The crystallization characteristics of the binary system polyoxyethylene (PEO)‐glutaric acid were determined. From the extrapolated melting point depression data the heat of fusion for PEO is 2506 ± 200 cal/mole of repeat unit while the heat of solution for the glutaric acid amounts to 6.7 ± 1.2 cal/cm 3 . A…
Abstract Metalloporphyrins perform a variety of functions in nature from the storage and transport of electrons and molecular oxygen to the decomposition of hydrogen peroxide and the activation of oxygen. The chemistry of both the centrally coordinated metal and the porphyrin macrocycle play important roles in these r…
The electrochemical “polarization resistance” method (also known as “linear polarization” method) was used in conjunction with a rotating iron electrode to investigate the effect of velocity and dissolved oxygen on the initial corrosion behavior of iron in high purity water. In low concentration, dissolved oxygen is c…
The carrier mobilities of PS were studied using a short-pulsed electron-beam. Even in the polymer with a π-electron system, no clear knee was observed in the induced charge signals at low applied fields. A logarithmic plot of the induced current versus time gives a knee at time T r , which is thought to be the transit…
The Voigt function fit to the experimental powder diffraction profiles of Ni, measured with neutrons and X-rays, is studied. In the neutron case the instrumental factors are dominant while the X-ray profiles are determined by the size and strains of the crystallites. The neutron diffraction profiles fit very well down…