Materials Literature
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The quenching of the fluorescence of trans-thioindigo and the inhibition of its photoisomerization to the cis-isomer by phenols support the idea that the photostability of indigo is due to a proton-transfer in the excited singlet state.
The recombination coefficient, γ′H and the energy accommodation coefficient, βH were simultaneously determined for hydrogen atom recombination on Ag, Au, Co, Cu, W, Fe, Ni and Pt filaments. Values of βH of 0.87, 0.65 and 0.43 were observed for Ag, Au and Cu, respectively, while values between 0.08 and 0.28 were observ…
Hardness measurements and electron microscopic observations were made to study factors affecting the aging of Mg–Zn alloy and Mg–Zn–(Ag) alloys. In regard to the homogeneous and heterogeneous nucleation in these alloys, direct aging, two-step aging and strain aging were carried out, with the results summarized as foll…
The kinetics for dissolution and deposition of solid aluminum in molten and electrolytes were studied by means of galvanostatic and potentiostatic techniques over a temperature range of 175°–313°C. The apparent exchange current densities varied from 1 to 56 mA/cm 2 . Surface diffusion was found to be the rate‐determin…
Solid‐state reactions of equimolar mixtures of Bi 2 O 3 and Fe 2 O 3 from 625° to 830°C and their kinetics were investigated. The reaction rates were determined from the integrated X‐ray diffraction intensities of the strongest peaks of the reactants and products. The activation energy for the formation of BiFeO 3 was…
A comparative study of the first-row transition metal ions Fe3+ and Mn2+ on the surfaces of aluminas and silicas has been made using the conventional techniques e.s.r., X-ray diffraction, magnetic susceptibility and in addition a relatively new technique phosphorescence spectroscopy.The results indicate that Fe3+ ions…
Aluminum was electrodeposited onto metallic substrates from a number of electrolytes consisting essentially of an solute of commercial purity and technical grade alkyl benzene solvents or solvent mixtures. Bright, fine‐grained, adherent aluminum coatings were obtained at cathode efficiencies of the order of 70–85% and…
Abstract The infrared spectra of the Mg(II), Co(II), Cu(II), Zn(II), Pd(II), Ni(II), and Ge(IV)Cl2 complexes of octaethylporphyrins have been studied over the range 4000–100 cm−1. Metal sensitive bands have been observed at about 980, 920, 340, 230, and 130 cm−1.
Crystals of hexaphenoxycyclotriphosphazene, [NP(OPh)2]3, are monoclinic, a= 11·176(4), b= 19·270(3), c= 16·171 (4)Å, β= 92·07(2)°, Z= 4, space group P21/n. The structure was determined with diffractometer data by Patterson and electron-density methods, and refined by block-diagonal least-squares methods to R 0·037 for…
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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…