Materials Literature
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A complex set of forces, both external and internal, governs the movements of nutrients through the environment. The circulation of mineral elements can be modeled as a system of compartments and transfer pathways. A simple version of this model has two valuable pedagogical uses. First, the idea of an equilibrium mine…
Measurements in a rectangular channel of the three viscosities η1, η3, η2 for laminar flow with the director parallel or perpendicular to the velocity or homeotropic orientation respectively, are reported for 4-n-octyloxy-4-cyanobiphenyl. In the nematic range, η1 has a pronounced divergence near the nematic/smectic tr…
Various correlation functions appearing in the theory of vibrating substitutional alloys with an arbitrary concentration of defects, including mass disorder as well as force-constant changes are calculated. The force-constant matrix is chosen such that the formalism of the locator-CPA can be applied to calculate the c…
It is proven that under suitable assumptions the change of symmetry associated with the bifurcation from the axisymmetric Maclaurin to the triaxial Jacobi ellipsoids can be described as a second-order phase transition in the entropy-volume plane. The proof is given by showing explicitly that the value of the eccentric…
Two series of novel methylene-bridged liquid crystals have been prepared. These molecules are quite wide and as a result only higher homologues exhibit mesomorphism. The enantiotropic mesophases are of the smectic C type. Trends in thermal behavior of these two series indicate that even higher homologues should posses…
The smectic properties of four series of esters — the methyl to n-decyl esters of the 4'-n-hexyloxy, 4'-n-heptyloxy-, 4'-n-octyloxy- and 4'-n-nonyloxy-biphenyl-4-carboxylic acids — are discussed. The effects on the smectic phases of increasing the alkyl chain lengths are quite striking, particularly in the last three…
Type material of Thalassiosira minuscula Krasske and material identified by the respective authors as Nitzschia delicatissima Cleve and Cyclotella nana Hustedt (= Thalassiosira pseudonana Hasle et Heimdal) have been examined in light and electron microscopes. It is suggested that the slide labelled “Nitzschia delicati…
Polyurethanes based on diphenylmethane 4,4′-diisocyanate (MDI) were examined by electronic spectroscopy and by continuous and laser flash photolysis. Fluorescence and phosphorescence emissions were observed, and although the source of the fluorescence could not be identified, the phosphorescence appears to originate f…
The general rule that addition of a non-mesogenic solute causes a sharp decrease in the nematic-isotropic transition temperature (TN→ I) of a nematic solvent is not obeyed when the solute and solvent can enter into a donor-acceptor interaction. Addition of 4-aminobiphenyl to the nematic liquid crystal 4-cyano-4′-penty…
Abstract Data on the Raman spectra of natural α‐Glycine and 15 N‐substituted α‐Glycine are presented together with details of a computer calculation of the normal vibrations. Assignments are made and compared with previous assignments based on IR measurements.
Magnetic measurements and metallographic investigations are reported on Sm(Co,Cu)z alloys. The compositions lie between the rare-earth (RE) to transition-metal (TM) ratios of 1 : 5 and 2 : 17 with a content of copper of up to 35% of the TM fraction. The materials were analyzed both in the as-cast and heat-treatment co…
Summary Apjohnite, MnAl 2 (SO 4 ) 4 ·22H 2 O, is monoclinic, space group P2 1 /c, a 6·198 (2), b 24·347 (4), c 21·266 (4) Å, β 100·28 (3)° and Z = 4. The crystal structure was determined by means of direct methods applied to X-ray data collected with a single-crystal diffractometer. At the end of the refinement, perfo…
A capillary dilatometer has been automated by means of a capacitive transducer technique. The precision is 1 : 105 over a range in volume of 4% for a sample volume of 2 ml. Differential scanning dilatometry is achieved by comparing the sample dilatometer with a reference dilatometer. Some results for the density chang…
The effect of aging on the microstructures of Sm-Co-Cu alloys is reported. It is shown that small precipitates are present within the SmCo5-type phase in as-cast material. On aging below 650 °C these precipitates are exceptionally stable, but at 800 °C they coarsen rapidly. These results are rationalized in terms of a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTManganese Schiff base complexes. 7. Synthesis and circular dichroism of optically active tetradentate chelates of manganese(III) and of .mu.-oxo-.mu.-hydroxo-dimanganese(III,IV) dimersL. J. Boucher and C. G. CoeCite this: Inorg. Chem. 1976, 15, 6, 1334–1340Publication Date (…
Completing sour gas wells with materials that possess innate corrosion resistance may be more practical than to attempt chemical corrosion inhibition of steel alloys. A program of screening tests determined that alloy systems containing large amounts of nickel, cobalt, chromium, and molybdenum have exceptional corrosi…
The measurement of dielectric strengths is generally beset with numerous difficulties, and results depend to a large extent upon experimental conditions and sample geometry. The development of so-called cylindrical samples, in which spherical electrodes are almost completely embedded in the dielectric to be measured,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure and magnetic properties of copper citrate dihydrate, Cu2C6H4O7.cntdot.2H2ODonald. Mastropaolo, Dana A. Powers, Joseph A. Potenza, and Harvey J. SchugarCite this: Inorg. Chem. 1976, 15, 6, 1444–1449Publication Date (Print):June 1, 1976Publication History Pub…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe effect of crystal packing and defects on desolvation of hydrate crystals of caffeine and L-(-)-1,4-cyclohexadiene-1-alanineStephen R. Byrn and Chung-Tang LinCite this: J. Am. Chem. Soc. 1976, 98, 13, 4004–4005Publication Date (Print):June 1, 1976Publication History Publi…
The naturally occurring toxin L-2-amino-4-methoxy-trans-3-butenoic (AMB) acid irreversibly inhibits pyridoxal phosphate-linked aspartate aminotransferase. The inhibitor is a substrate for the enzyme, and as such is converted into a highly reactive intermediate which chemically reacts with an active site residue, thus…