Materials Literature
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Abstract The structure of isotactic poly(2‐vinylpyridine) has been determined from x‐ray fiber data utilizing rigid‐body least‐squares refinement techniques. The polymer exists as a threefold helix with three chains passing through a hexagonal unit cell having the dimensions a = b = 15.49 Å and c = 6.56 Å (fiber axis)…
Molybdenum Kα X-radiation, monochromated by an NaCl single crystal, was scattered in 1-propanol at -25°C. The angular distribution of the scattered X-ray intensity was determined and used for the calculation of the experimental pair function. On the basis of some models of the structure of liquid 1-propanol, the theor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe carbonyl scrambling processes in the isomeric pentacarbonylguaiazulenediiron and homologous ruthenium molecules; a novel mechanism for the internuclear processesF. Albert Cotton, Brian E. Hanson, John R. Kolb, Pascual Lahuerta, George G. Stanley, B. Ray Stults, and Alan…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbon-13 Spin Relaxation Parameters of Semicrystalline Polymers. Linear PolyethyleneR. A. Komoroski, J. Maxfield, F. Sakaguchi, and L. MandelkernCite this: Macromolecules 1977, 10, 3, 550–556Publication Date (Print):May 1, 1977Publication History Published online1 May 2002P…
Abstract The thermal decomposition of poly(butene‐1 sulfone), poly(pentene‐1 sulfone), poly(hexene‐1 sulfone), poly(styrene sulfone), and polystyrene was investigated in helium at a heating rate of 20°C/min using an experimental system which consists of a programmable pyrolyzer, a thermal conductivity detector, a mass…
Reduction of tissues with sodium cyanoborohydride at pH7.4 gave results identical with those obtained by KBH4 treatment. On reduction with sodium cyanoborohydride at pH 4.4, however, a previously undetected basic compound was formed and was identified by mass spectrometry and chemical degradation techniques as dihydro…
The effects of dispersion and sieving on the determination of fiber content was studied using four peat materials selected for their range of properties. In addition, a method of particle-size analysis of peat materials and chemical characterization data of the particular-size fraction are presented. Controlling the s…
The synchrotron X-ray beam produced by the SPEAR storage ring at the Stanford Linear Accelerator Center has been used as a tuneable and intense source for single-crystal-protein diffraction experiments. A measurement of the absolute intensity of a focused, monochromatized X-ray beam gave a value of 3 × 109 photons s-1…
An outline is given of some of the steps which in the last ten years have led to an understanding of many of the properties of conduction and valence bands in non-crystalline materials. The concept of a mobility edge is described and some of the experimental evidence for its existence is presented. A discussion is giv…
Die Röntgen‐Strukturanalyse von B 2 S 3 scheiterte bisher an der schlechten Qualität des Kristallmaterials. Jetzt konnten Einkristalle erhalten werden, an denen sich die Struktur aufklären ließ. magnified image
Abstract A series of starch graft copolymers and one cellulose graft copolymer were prepared containing 40‐50 percent synthetic polymer. The monomers used (styrene, methyl methacrylate, methyl acrylate, and butyl acrylate) were chosen to give grafted synthetic polymers with varying glass transition temperatures (T g )…
The isotope effect for 22 Na/ 24 Na diffusion was measured for three 25‐mol% alkali‐silicate glasses. A multiple diffusion mechanism wherein the Na ions diffuse both singly (vacancy mechanism) and in pairs (interstitialcy mechanism) provided the best agreement with the experimental data. According to this tentative mo…
Abstract The static and impact properties of hybrid composite systems containing various high performance fibers in an epoxy matrix have been studied as a function of lamination configuration. From instrumented impact test data, fracture initiation and propagation energies were calculated and reported in terms of a me…
Abstract not Available.
Abstract The engineering properties of polyurethane–poly(methyl methacrylate) simultaneous interpenetrating networks (SIN's) were evaluated. The hardness behavior reflected the observed phase inversion in the electron‐microscopic studies. The maximum ultimate tensile strength was observed at 85% polyurethane–15% poly(…
Abstract A series of acetylene‐terminated phenylquinoxaline oligomers have been prepared which cure by addition, without the evolution of volatiles. The synthesis utilized the novel terminal acetylene end‐capping reagent, 3‐(3,4‐diaminophenoxy)phenylacetylene. The end‐capped oligomers were soluble (20–30%) in low‐boil…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteraction of Cyclodextrin-Containing Polymers with Fluorescent CompoundsAkira Harada, Masaoki Furue, and Shun-ichi NozakuraCite this: Macromolecules 1977, 10, 3, 676–681Publication Date (Print):May 1, 1977Publication History Published online1 May 2002Published inissue 1 Ma…
Thermal and magnetic properties of a mixture of two anisotropic antiferro-magnets with different easy axes have been analyzed both in mean field approximation and in the method of distribution function. A new phase called OAF phase is found within a certain range of concentration. In OAF phase, the spin of each specie…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe "Δη Effect" and Polystyrene-Poly(vinyl methyl ether) Compatibility in SolutionA. Robard, D. Patterson, and G. DelmasCite this: Macromolecules 1977, 10, 3, 706–708Publication Date (Print):May 1, 1977Publication History Published online1 May 2002Published inissue 1 May 197…
The electrical breakdown field strength in SF6calculated from measurements has been found to deviate considerably from the values predicted by the theoretical models used up to now. The simplest form of the streamer criterion predicts breakdown to take place at field strength - to - pressure ratios close to 8.9 kV/mm…