Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular stereochemistry of a nitrogen-bridged metalloporphyrin: .mu.-nitrido-bis[.alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinatoiron]W. Robert Scheidt, David A. Summerville, and Irwin A. CohenCite this: J. Am. Chem. Soc. 1976, 98, 21, 6623–6628Publication Date (Print)…
The angle between the nematic director and an aligning surface in contact with a nematic phase is of importance in defining the mechanism of surface alignment of liquid crystals. A new and simple optical method of determining this tilt angle is described, and measurements are reported on a number of homologues of the…
Thermal-expansion measurements were made for five varieties of mixed-alkali silicate glasses (Na-K, Na-Rb, Na-Cs, K-Rb, and K-Cs), with special emphasis on the Na-K silicates. Negative deviations from additivity were observed in the glass transformation temperature in every case, with the deviations increasing with to…
Charging and discharging current transients in polypropylene films were measured over a wide range of temperatures and electric fields. Some limited studies of the behaviour of these current transients were also made with different electrode materials and sample thicknesses. The experimental evidence suggests that the…
The trace of the force-dipole tensor (A+2B) as well as the components A and B of hydrogen interstitials in niobium were determined from measurements of the lattice parameters of the alpha , alpha ' and beta phases. It is shown that the orthorhombic structure of the beta phase is due to a direct hydrogen-hydrogen inter…
Abstract ABS systems which differ distinctly in particle size and degree of grafting were prepared and investigated by dynamic mechanical measurements as function of temperature in the glass transition region of the rubber phase. Variation of rubber content within different sample series results in effects which were…
Using the method of small-angle x-ray scattering (SAXS), the time-dependent structural changes in some linear-segmented urethanes have been investigated. The results directly support the time- and temprature-dependent morphological model proposed earlier by one of the authors. Specifically, upon heating of many linear…
1. Fractionation of fibroin prepared from the posterior silk glands of Bombyx mori was carried out. After carboxymethylation of the fibroin, it was fractionated by ammonium sulfate precipitation, Sephadex G-200 gel filtration and DEAE-cellulose column chromatography. 2. The fibroin was composed of at least two protein…
The most successful techniques for producing graphite-aluminum com posites have been those that utilize liquid-metal infiltration of graphite yarn. Almost all grades and types of graphite yarn can be infiltrated; how ever, a fiber coating is required, which results in wetting and provides a diffusion barrier to inhibi…
Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution and have already been profoundly affected by the application of existing ML ...Read More
"Optical Properties of Solids-New Developments." Optica Acta: International Journal of Optics, 23(10), pp. 841–842
The Sondheimer oscillations in the electrical resistivity and the Hall coefficient have been measured in copper single crystals. The magnetic field was oriented to the [100] and close to the [110] directions, and it is shown that in these cases the oscillations are interpreted as the type 2 according to the theory of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT[Mo3(OAc)6(CH3CH2O)2(H2O)3]2+ and other new products of the reaction between molybdenum hexacarbonyl and acetic acidA. Bino, M. Ardon, I. Maor, M. Kaftory, and Z. DoriCite this: J. Am. Chem. Soc. 1976, 98, 22, 7093–7095Publication Date (Print):October 1, 1976Publication Hist…
Abstract Es wurden die Verbindungen MgAl 2 Se 4 , MgIn 2 Se 4 und Mg 2 Al 2 Se 5 dargestellt und analytisch gesichert. Sie kristallisieren trigonal mit den Daten: Die Strukturen lassen sich auf dichteste Kugelpackungen der Selenanionen zurückführen, wobei durch eine spezielle Besetzung der Tetraeder‐ und Oktaederlücke…
The effects of doping and uniaxial stress on the structural and magnetic properties of VO2 are reviewed. Important electron-electron correlation effects are deduced : (i) in the metallic phase from the results obtained V1-xNbxO2 alloys, (ii) in the insulating phases of pure VO2 at ambiant pressure (M1), under uniaxial…
Abstract Es wird über die Darstellung, die Eigenschaften und die röntgenographische Untersuchung von Cu 2 BaSnS 4 (A) und Ag 2 BaSnS 4 (B) berichtet. (A) kristallisiert trigonal, — Raumgruppe C –P3 1 mit a = 6,36 7 und c = 15,83 3 Å — und ist mit Cu 2 SrSnS 4 [1] isotyp. (B) hat eine orthorhombische Elementarzelle: a…
Abstract A non‐Gaussian theory of the stress‐induced crystallization of polymeric networks is presented. It is predicted that for uniaxial extension of crosslinked polyethylene, a perfectly oriented, extended‐chain crystal is formed initially, changing to one‐fold crystal oriented perpendicular to the stretch directio…
Abstract The reaction of cellulose with phosphorous acid in molten urea afforded a white, water‐soluble product. The product was a monoester of phosphorous acid, and all the phosphorus residues were in phosphonic form, i.e., cellulose phosphonate. Quantitative addition of acrylonitrile to the PH bonds in cellulose ph…
Explicit expressions are obtained for the line energy of straight dislocations in orthorhombic polyethylene crystals. It is found that the ⟨0, 0, c⟩ screw dislocation is the perfect dislocation with the lowest line energy whilst the ⟨0, 0, c⟩ edge has negative line tension and is therefore unstable. The possible disso…
Following the dramatic impact of the first protein structure determinations, the field of macromolecular crystallography has expanded with ever-increasing rapidity. In many cases the techniques used are the same as those pioneered by Perutz and Kendrew and their disciples, but the preoccupation has shifted from method…