Materials Literature
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The validity of the Sayre equation [Sayre (1952). Acta Cryst. 5, 60-65] for (3 + n)-dimensional periodic structures is examined. A practical procedure is proposed for the determination of incommensurate modulated structures; this is an extension of the direct method previously proposed for solving superstructures [Fan…
The temperature dependence of the solubility of proton defects in SrTiO 3 single crystals was investigated by IR spectroscopy. Based on the integrated absorption of the OH stretching vibration bands, the enthalpies of the dissolution reaction were determined for undoped and Fe-doped SrTiO 3 . In contrast to undoped Sr…
We show that a dislocation-loop theory of the smectic-A--nematic transition predicts the existence of both nematic regions surrounded by smectic regions and a smectic--${A}_{1}$-${A}_{d}$ critical point in the phase diagram, in agreement with recent observations. Fluctuation-corrected mean-field theory leads to a rema…
The phase diagram of growing crystal patterns for succinonitrile is obtained experimentally in a supercooling-anisotropy phase space. The anisotropy of the crystal growth is changed by roughening the upper surface of the bottom plate of the thin crystal-growth cell. Various growing modes are observed, and the relation…
Nonlinear optical effects offer devices which allow the control of a light beam with another light beam or an applied electric field. After a brief introduction to some nonlinear optical effects various organic materials and their applications in this area are discussed.
A random-resistor model proposed recently for dispersed ionic conductors is generalized to study the effect of dispersed particle size on the conductivity of such composites. Monte Carlo calculations for two-dimensional systems are reported for square as well as rodlike particles of different size. It is found that th…
Abstract The temperature rising elution fractionation (TREF) technique makes use of the differential crystallizabilities, introduced by short chain branches (SCB), to fractionate polyethylenes (PE) on the basis of the SCB level of any one chain. This allows one to probe the SCB distribution of a polymer. The TREF tech…
Abstract Morphological consequences of a localized diffusion of segregated species at crystal growth fronts have been studied in two specific contexts: (1) variation of texture in spherulites grown in unfractionated polyethylene over a range of crystallization temperatures mostly in regime II, and (2) development of e…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfluence of fluoride ions on the absorption and luminescence properties of the [Eu.cntnd.2.2.1]3+ and [Tb.cntnd.2.2.1]3+ cryptatesN. Sabbatini, S. Perathoner, G. Lattanzi, S. Dellonte, and V. BalzaniCite this: J. Phys. Chem. 1987, 91, 24, 6136–6139Publication Date (Print):N…
Abstract Tetraphenylporphinesulfonate (TPPS 4 ) is a synthetic porphyrin that localizes in certain tumors to a higher absolute concentration and with more favorable tumor to other tissue ratios than any other porphyrin yet studied. Its utilization for photodynamic therapy and other applications has been inhibited by r…
Abstract This second paper of a series continues the examination of the tensile properties of two series of linear low density polyethylene/polypropylene, (LLDPE/PP) blends. The blends were prepared using a twin‐screw extruder and cover the whole concentration range, An Instron Universal Tensile Tester was used to mea…
A kinetic mechanism is presented for Escherichia coli dihydrofolate reductase which describes the full time course of the enzymatic reaction over a wide range of substrate and enzyme concentrations at pH 7.2 and 20 degrees C. Specific rate constants were estimated by computer simulation of the full time course of sing…
We report structural studies of incommensurate and random GaAs-AlAs superlattices using Raman scattering by acoustic phonons. Properties of the structure factor of Fibonacci and Thue-Morse superlattices are discussed in some detail.
Abstract There is considerable economic incentive to convert methane into formaldehyde, which is used in the manufacture of insulating materials and adhesives. This paper discusses the kinetics of a one‐step oxidation of methane with molecular oxygen over a MoO 3 ‐SiO 2 catalyst. The space velocity was varied between…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of new polymers containing porphyrins in their side chains: radical polymerizations of 5-[4-(acryloyloxy)phenyl]-10,15,20-triphenylporphyrin and 5-[4-(methacryloyloxy)phenyl]-10,15,20-triphenylporphyrinMikiharu Kamachi, Xian Su Cheng, Tomikazu Kida, Atushi Kajiwara…
Vimentin is a growth-regulated gene whose mRNA levels increase severalfold after stimulation of quiescent cells. We have isolated and sequenced a genomic fragment of human DNA containing the vimentin 5'-flanking sequence and untranslated region. S1 nuclease analysis was used to determine the transcription initiation s…
The details of photoluminescence and excitation spectra of powder phosphors were obtained at various temperatures between 6 and 300 K. At 300 K, two emission bands originating from the , transitions are observed at 480 and 535 nm for and at 470 and 527 nm for , respectively. In the excitation spectra, bands correspond…
Abstract It has been reported that the addition of specific copolymers can improve the mechanical properties of blends of polyethylene with polyamide‐6. One of these, a poly(ethylene‐co‐methacrylic acid) (EMA) containing between 4 and 15 mol % of methacrylic acid units, has often been used. Binary polyethylene/EMA and…
Electrodeposited tungsten oxide films from aqueous tungstic acid-hydrogen peroxide solutions were investigated for applications to electrochromic devices. These films exhibited electrochromism in aprotic electrolyte solutions containing Li-salts. When the films were heat-treated for an hour at temperatures between 100…
A cDNA clone, named ppcMDH-1 and covering a part of the coding region for the porcine cytosolic malate dehydrogenase (cMDH) mRNA, was isolated from a porcine liver cDNA library. Subsequently, mouse cMDH cDNA clones were isolated from mouse liver and heart cDNA libraries, using the ppcMDH-1 cDNA as a probe. The longest…