Materials Literature
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A model, proposed originally by Dexter, Klick and Russell, is used to explain the occurence or non-occurence of F-center luminescence in ionic crystals, in terms of a simple two-state configuration coordinate diagram. In this model, which works for all known cases, luminescence is quenched by a competing non-radiative…
Neutron-elastic-scattering experiments performed on deuterated TTF-TCNQ single crystals reveal two structural transformations at 38 \ifmmode\pm\else\textpm\fi{} 0.5 K and at 54 \ifmmode\pm\else\textpm\fi{} 1.0 K. Below 38 K, a $4\stackrel{\ensuremath{\rightarrow}}{\mathrm{a}}\ifmmode\times\else\texttimes\fi{}3.4\stack…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of temperature on optical basicity in the sodium oxide-boric oxide glass systemJ. A. Duffy and R. J. GrantCite this: J. Phys. Chem. 1975, 79, 25, 2780–2784Publication Date (Print):December 1, 1975Publication History Published online1 May 2002Published inissue 1 Decemb…
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Pyrrole mit ankondensiertem siebengliedrigem Ring , das heißt Verbindungen der Strukturen (1) und (2) , sind synthetisiert worden. Sie dienen dem Studium der spektroskopischen Eigenschaften und des chemischen Verhaltens von Pyrrolen in Abhängigkeit von der Lage des π‐Elektronensystems magnified image .
The relative amounts of the α- and γ-crystalline forms of nylon 6 obtained from the glassy state under different crystallization conditions have been studied by the X-ray diffraction procedure described in the previous paper. The weight fraction of the γ-form decreases with increasing crystallization temperature above…
Abstract For the self‐consistent (SC) calculation of solids an approach is suggested combining the “large unit cell” method with the theory of representative (special) pointsin the Brillouin zone. In the framework of the approach suggested the SC calculation of a solid can be realized by the self‐consistent methods de…
The total and differential elastic scattering cross section of electrons by atomic oxygen and nitrogen is calculated for energies between 1 and 500 eV in the distorted-wave (DW) approximation. The DW method has been modified by the inclusion of a polarization potential with an adjustable cutoff parameter which is dete…
Magnetic domain behavior in a sintered Co-Cu-Fe-Sm magnet was studied using the Kerr effect. Magnetic reversal initiated in thin bands along most grain boundaries and extended from these bands into the interior of the grains. Domain walls were immobile at low fields. Transmission electron microscopy and microprobe ana…
Matrix variational calculations of electron scattering by atomic C have been carried out, including target atom configurations $2{s}^{2}2{p}^{2}$, $2s2{p}^{3}$, and $2{p}^{4}$ and all possible single virtual excitations of the $2p$ orbital. Total and differential elastic and inelastic cross sections are reported for e…
Abstract The kinetics of crystallization and dissolution of barium sulfate seed crystals were investigated conductimetrically. Growth is characterized by an initial surge caused by secondary nucleation, followed by a rate that is proportional to The square of the supersaturation. Studies were made using seed material…
Abstract An experimental study of the co‐extrusion of polyethylene and TiO 2 ‐filled polyethylene through capillary and rectangular cross‐section dies has been carried out. The influence of viscosity ratio, cross‐section type, die length and duration of flow has been studied. Low viscosity melts will encapsulate high…
Using combined ${\mathrm{Er}}^{3+}$ absorption spectroscopy and bulk magnetization measurements, the magnetic properties of ErCr${\mathrm{O}}_{3}$ in the ${\ensuremath{\Gamma}}_{1}$, ${\ensuremath{\Gamma}}_{2}$, and ${\ensuremath{\Gamma}}_{4}$ phases have been studied as a function of temperature and external field. T…
An empirical correlation shows that the activation energy for plastic flow in covalent solids equals twice the energy gap. This provides evidence that the flow rate is controlled by the rate of tunneling of bonding electrons into nonbonding states under the influence of the applied stress. The model yields an explicit…
The correlation between low-shear Newtonian melt viscosity and polymer molecular weight distribution in the high molecular weight region is inspected via the viscosity of homologous binary blends. It is confirmed that viscosity depends uniquely upon the weight average molecular weight and no other moment. The work of…
Abstract In the melt crystallization of isotactic polypropylene, poly(ethylene oxide) and poly(butene‐1) in contact with substrates, the existence of a fixed number of nucleating sites on the substrate surfaces has been established. When these sites become active successively (the transient in the number of nuclei is…
Abstract An attempt to determine protein denaturing potency of typical surfactants has been made by measuring specific rotation of bovine serum albumin. The potencies obtained were examined in relation to the intensities of skin roughness in vivo caused by the surfactants, and a noticeable correlation was found betwee…
SUMMARY Cyclotella atomus Hust., C. meneghiniana Kütz., C. comta (Ehr.) Kütz., C. antiqua W. Sm., C. michiganiana Skv., C. ocellata Pant., C. glomerata Bachmann, C. pseudostelligera Hust., and C. stelligera (Cleve et Grun.) V. H., were selected for ultrastructure investigations on the basis of their ready availability…
Electron microscopy reveals a characteristic structural organization consisting of poorly organized spherulites with an open fibrous texture in which the strands appear to be built up from microfibils. X-ray and birefringence results are also discussed.
Insoluble collagen was prepared from bovine periodontal ligament. Isolation and characterization of CNBr peptides originating from the alpha1(I), alpha2, and alpha1(III) chains showed that the tissue contained both type I and type III collagens. Further evidence for the presence of type III collagen was obtained by th…