Materials Literature
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Abstract The wood cell wall is composed of chemically and structurally different components. The cellulose molecules are smooth long chains, able to aggregate in longitudinal direction to compact fibrils. The polyoses consist of shorter chains with side groups and branching points so that they are not able to aggregat…
The preparation of 21-oxa, 21-thia-, 21,23-dioxa-, 21,23-dithia-, and 21-oxa-23-thia-porphins is described. These new porphin analogues have spectral properties similar to those of the porphins, which supports their formulation as aromtic macrocycles. Surprising basicity is displayed by 21,22- and 21,23-dioxaporphins…
Manganese‐activated SrAl 12 O 19 and CaAl 12 O 19 phosphors have been prepared under oxidizing and reducing conditions, and by direct cation exchange. The red emission of oxidized phosphor and green emission of reduced phosphor confirm previous assignments to octahedral Mn 4+ and tetrahedral Mn 2+ , respectively. New…
The ionic conductivity of polycrystalline lithium iodide containing 0 to 3% (mole) calcium iodide was studied at temperatures between −30° and 130°C.The conductivity increased linearly with the concentration of calcium iodide, and it was concluded that the introduction of calcium ions to the lithium iodide crystals in…
Abstract The effect of liquid ammonia on cotton fabric was studied using x‐ray diffraction (XRD) and electron microscopy. A phase diagram is presented describing the relationship between disordered cellulose, cellulose I, and cellulose III. The transition from cellulose I to III proceeds through the liquid ammonia. Ce…
The electrical conductivity of sintered specimens of was measured over the temperature range 800°‐1500°C and from 1 to 10 −21 atm of oxygen. Based on the agreement between these experimental data and theoretically derived relations obtained using the law of mass action, the nonstoichiometric defect structure of was in…
Inelastic stress response under strain cycling conditions is analyzed in terms of the three important governing phenomena, namely, memory of prior history, cyclic hardening or softening, and cyclic mean stress relaxation. Independent formulations to describe these respective features consist of a set of hysteresis rul…
Abstract The solid‐state photochemistry of several substituted anthracenes has been investigated with particular reference to the behaviour of polymorphic forms of the monomers. A class of 9‐substituted anthracenes (methyl, methoxycarbonyl, chloro, bromo) crystallising in anti‐parallel, sandwich packing arrangements g…
The 119Sn Mössbauer data and electronic reflectance spectra of the cubic caesium tin(II) halides CsSn Br3 –xClx(x= 0–3) and their behaviour on heating suggest that the non-bonding tin(II) electrons may be involved in a band structure rather than being located in non-bonding molecular orbitals in these materials.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and polymerization of bridgehead-substituted bicyclobutanesHenry Kingston Hall Jr., Claibourne D. Smith, Elwood P. Blanchard Jr., S. C. Cherkofsky, and J. B. SiejaCite this: J. Am. Chem. Soc. 1971, 93, 1, 121–130Publication Date (Print):January 1, 1971Publication H…
The electronic states of Mn 2+ are derived from excitation spectra for eight orange‐to‐red emitting phosphors: ( i ) , ( ii ) , ( iii ) , ( iv ) , ( v ) , ( vi ) , ( vii ) , and ( viii ) . All eight phosphors show complete splitting of at least one electronic level. The observed splittings are compared to the expected…
Abstract : The TPRC Data Series published in 13 volumes plus a Master Index volume constitutes a permanent and valuable contribution to science and technology. This 17,000 page Data Series should form a necessary acquisition to all scientific and technological libraries and laboratories. These volumes contain an enorm…
THE PURPOSE OF THIS PAPER IS TO PREDICT THE FATIGUE LIFE OF PAVING MIXTURES IN TERMS OF MATERIAL CONSTANTS, GEOMETRY, BOUNDARY CONDITIONS, AND THE STATE OF STRESS. FATIGUE IS DEFINED IN TERMS OF CRACK INITIATION, INFLUENCES ON CRACK GROWTH, AND CRITICAL STRESS INTENSITY AT THE CRITICAL FAILURE POINT. CRACK GROWTH PARA…
Abstract The effect of increasing the substitution of water‐soluble hydroxyethyl cellulose (HEC) and hydroxypropyl cellulose (HPC) is to decrease their affinities for water. This is consistent with data given on the cloud point, salt tolerance, surface tension of aqueous solutions, and solubility in organic solvents,…
A synopsis of experimental results on the anodic dissolution of iron is given. From these data the existence of two different reaction mechanisms is proved, of the noncatalyzed (Bockris) mechanism and of the catalyzed (Heusler) mechanism. The current density‐potential relations under steady‐state and nonsteady‐state c…
The new terdentate ligand 2,6-di(diphenylphosphinomethyl)pyridine forms a series of crystalline complexes, MLX2, with iron(II), cobalt(II), and nickel(II) halides and thiocyanates. Distorted square pyramidal structures are suggested on the evidence of their electronic spectra and other physical properties. Magnetic su…
The distribution coefficients of Sr and Ba were measured when Mg-poor calcite, Mg-rich calcite or aragonite was precipitated in the calcium bicarbonate solutions containing strontium or barium in trace amounts, MgCl2, NaCl and/or Na-citrate. The abnormally high values of the distribution coefficients were observed ver…
This paper describes the monomer types commonly used in making thermoplastic polyurethane elastomers. It gives chemical structure of the polymers and their general properties. Also de scribed are studies of the hydrolysis of thermoplastic polyurethane elastomers. This will include information on author's choice of hyd…
Abstract The crystallinity, elastic modulus, and tensile strength of samples of various draw ratios together with the true stress—strain curves of high‐density polyethylene were determined to establish correlations with morphological changes occurring during deformation. Changes of crystallinity at draw ratios below 5…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilicon-transition metal chemistry. I. Photochemical preparation of silyl(transition metal) hydridesWilliam A. G. Graham and W. JetzCite this: Inorg. Chem. 1971, 10, 1, 4–9Publication Date (Print):January 1, 1971Publication History Published online1 May 2002Published inissue…