Materials Literature
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The valve morphology of the brackish-water plankton diatom Skeletonema subsalsum is dependent on salinity. In cells grown at salinities of 3‰ or less, the valve faces were flat and the connecting processes much reduced in length. Cells grown at salinities of 5‰ or higher had dome-shaped valves and extended connecting…
The field dependence of the proton NMR second moment ${M}_{2}(H, T)$ of powder N-methylphenazinium-tetracyanoquinodimethane (NMP-TCNQ) and (DMP-TCNQ), the analogous material with a deuterated methyl, shows that at 4.2\ifmmode^\circ\else\textdegree\fi{}K there are unpaired electrons localized on \ensuremath{\sim} 6% of…
The corrosion of copper in oxygenated sulfuric acid solutions was studied by means of weight‐loss and polarization curves. At a given potential, the rate of copper dissolution is greater in the presence than in the absence of oxygen reduction, which is contrary to the conventional theory of mixed potentials. An explan…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganocobalt cluster complexes. XVIII. Friedel-Crafts acylation of diarylacetylenedicobalt hexacarbonyl complexes. Dicobalt hexacarbonyl unit as a protecting group for the acetylene functionDietmar Seyferth, Mara O. Nestle, and Anthony T. WehmanCite this: J. Am. Chem. Soc. 1…
It is shown that it is necessary to use an angle-dependent doublet separation within a given profile when performing an α2 elimination in X-ray diffraction line profiles. Two formulations for the doublet separation are suggested, which give better results than the doublet separation as obtained from a differentiation…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMixing of ionic and covalent configurations for sodium hydride, potassium hydride, and hydromagnesium(1+). Potential energy curves and couplings between molecular statesRobert W. Numrich and Donald G. TruhlarCite this: J. Phys. Chem. 1975, 79, 25, 2745–2766Publication Date (…
Rotational analyses have been carried out, with varying degrees of completeness, for nine bands of S 16 O 2 and two bands of S 18 O 2 in the region 3000–3300 Å. The bands are all highly perturbed type C bands, which go to b 2 vibrational levels of the ππ* Ã 1 A 2 electronic state. The [Formula: see text] electronic tr…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNonparameterized molecular orbital calculations of ligand-bridge Fe2(CO)6X2-type dimers containing metal-metal interactionsMichael B. Hall, Richard F. Fenske, and Lawrence F. DahlCite this: Inorg. Chem. 1975, 14, 12, 3103–3117Publication Date (Print):December 1, 1975Publicat…
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…