Materials Literature
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New intermetallic compounds of the ThCr 2 Si 2 -structure type have been prepared and their structures determined by single crystal data.
Fe2SiS4 and Fe2GeS4 have the olivine structure with space group Pnma. Cell dimensions are a= 12.407 (2), b=7.198(1), c= 5.812(1) /~ for Fe2SiS4 and a= 12.467(2), b=7.213(1), c= 5.902(1) /~ for Fe2GeS4. The crystal structures were refined by least squares to final values of R=0.052 and 0044 respectively for Fe2SiS4 and…
Abstract not Available.
The simple method of solving the Green-Ampt one-dimensional infiltration equations developed from Darcy's law are proposed for practical applications. The explicit solution is an approximation obtained by employing a power series expansion of the logarithmic term. The maximum error resulting from applying this simple…
Abstract Darstellung und Einkristallzüchtung der schwer zugänglichen Verbindung Cs 4 O werden beschrieben. Die bei −30°C durchgeführte Strukturuntersuchung ergibt einen Aufbau gemäß der Formel [Cs 11 O 3 ]Cs. Die für Cäsiumsuboxide charakteristischen Cs 11 O 3 ‐Gruppen bilden eine hexagonal dichte Anordnung, in der di…
Summary Extraction of five soils with acetylacetone in benzene does not change their particle‐size distribution, compared with no pre‐treatment or dispersion, but it decreases the water stability of soil aggregates. The decrease is closely related to the extent of the extraction of iron and aluminium by acetylacetone…
Na 3 NO 3 ist kein Salz der „orthosalpetrigen Säure”︁ H 3 NO 3 , sondern ist als Addukt [NO 2 − ]ONa 3 zu formulieren. Zu diesem Ergebnis führte die Röntgenstrukturanalyse, die keine NO 3 3− ‐Anionen erkennen ließ magnified image .
Abstract The amide‐exchange reactions which cause copolymer formation in polyamide melt blends were studied with mixtures of N ‐ethylcaproamide and N ‐hexylacetamide containing small concentrations of caproic acid and hexylamine as a model system for melt blends of aliphatic polyamides. Amide exchange was found to inv…
Revue bibliographique sur l'analyse des structures stratifiees dans lesquelles des couches de materiau viscoelastique sont utilisees pour l'amortissement des vibrations
This paper describes test methods used to study the phenomenon of electrical treeing in solid dielectrics. Measurements of double needle characteristic voltage and voltage life for a variety of useful dielectric materials are presented. The effects of additives upon treeing in polyethylene are discussed, and evidence…
Some physical, catalytic, and regulatory properties of ketopantoate hydroxymethyltransferase (5,10-methylenetetrahydrofolate: alpha-ketoisovalerate hydroxymethyltranferase) from Escherichia coli are described. This enzyme catalyzes the reversible synthesis of ketopantoate (Reaction 1), an essential precursor of pantot…
The 11B and 207Pb NMR spectra have been used to study the structure of glasses in the system PbO–B2O3–SiO2. The results indicate that the glasses do not contain an appreciable number of BO−3 units, and the network-forming lead atoms play an important role in the compositional behavior of N4 (the fraction of boron atom…
A number of local potentials have been suggested to represent the non-local exchange kernel in electron-atom scattering. A comparative numerical study has been made in which phase shifts for the elastic scattering of electrons by H, He+ and He using these potentials are tested against those calculated from the exchang…
New measurements of electrical conductivity along the $b$ axis of tetrathiafulvalenium-tetracyanoquinodimethanide (TTF-TCNQ) are combined with published results to provide a comprehensive summary including approximately 600 samples studied at 18 different laboratories. The magnitudes of these measured conductivities d…
An experimental study of foam extrusion was carried out to determine the effect of processing variables on the quality of the foam produced. For the study, the chemical blowing agent azodicarbonamide was used, together with an activator and a nucleating agent, to produce thermoplastic foams of low-density polyethylene…
Abstract A polycarbosilane, the starting material of β-SiC fibers, was prepared without autoclave. The new method is simple and more economical than the previous one. Furthermore, a great number of bundles of SiC fibers were obtained by way of oxidative reactions of polycarbosilane fibers.
Synthetic CaTiSiOu has been shown to undergo a reversible, displacive phase transition at 220 + 20oC from space group P2r/a to A2/a, using high-temperature single crystal X-ray diffraction techniques. The transition is signaled by disappearance of reflections of the type hkl: k + / odd. The structure of a synthetic P2…
Abstract Scan electron micrographs are shown of (1) kaolinite and dickite which crystallized from solution within cavities, (2) kaolinite weathered from clastic primary silicate material, (3) residual kaolinite from primary silicate rock, (4) kaolinite above and below a basal unconformity on granitic rock, and (5) hyd…
Abstract The formation energy of vacancies is measured under conditions of very low vacancy concentrations for ultrahigh purity aluminium, after quenching down to 4 K. A value of (0.69 ± 0.03) eV is found. Similar experiments made using pure magnesium yield a formation energy of (0.79 ± 0.03) eV. It is shown that in m…
Flexoelectric effects are observed in both the nematic and smectic-A phases of p-butoxybenzal-p- (β-methylbutyl) aniline (BBMBA) and p-cyano-benzylidine-p-octyloxyaniline (CBOOA). This is the first reported observation of flexoelectricity in smectic phases. The use of a symmetric interdigital electrode in the homeotro…