Materials Literature
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Abstract A series of derivatives of meso ‐tetraphenylporphine, with neutral, acidic and basic functional groups, has been prepared. Several of these compounds were synthesized directly via the Rothemund reaction, under a variety of conditions to obtain optimal yields; others were prepared by interconversions of variou…
Abstract Li 2 SnO 3 tritt in zwei Modifikationen auf, einer α‐Form unterhalb 800°C, welche zu den Raumgruppen C 2h 3 = C2/m oder D 3 3 = C3 1 12 oder der enantiomorphen D = C3 2 12 gehört, und einer oberhalb 1000°C stabilen β‐Form in C = C2/c. Diese Strukturen entsprechen verschiedenen Stapelungen von wabenartigen Sn‐…
Some practical problems associated with the use of beryllium as a mirror substrate material are analyzed, with particular emphasis on nonelastic strains that may affect mirror performance. Present information on the nonelastic behavior of beryllium is summarized.
The paramagnetic relaxation of ClO2 in dilute solution was studied as a function of temperature, viscosity, and solvent system. In paraffin solutions, where the ClO2—solvent interaction is apparently small, the ClO2 electron paramagnetic resonance linewidth is linearly proportional to temperature but essentially unaff…
A simple treatment is given of the effect of eddy current damping on the equation of motion of the magnetization vector in a uniform thin ferromagnetic film switching by coherent rotation. It is concluded that for films thicker than about 6000 Å the eddy current damping mechanism is predominant.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular Ions. VII. Positive Ions of Olefins in γ-Irradiated Organic GlassesTadamasa Shida and William H. HamillCite this: J. Am. Chem. Soc. 1966, 88, 23, 5376–5380Publication Date (Print):December 1, 1966Publication History Published online1 May 2002Published inissue 1 Dec…
Perovskite phases containing iron in both the tetravalent and trivalent states were prepared by equilibration at high oxygen pressures. Small bismuth additions to SrFeO 3 resulted in high conductivity (10 1 to 10 3 (ohm‐cm) –1 at 26°C) and antiferromagnetic order below 130°K. Distortion to tetragonal symmetry occurs a…
The effect of input tension and cam setting on fabric quality and plain-knitted loop formation is investigated in detail, using a lubricated viscose staple yarn. It is indicated that the K 1-4 values are not strictly constants, but are variable when a wide range of knitting stiffnesses are studied. An investigation of…
Abstract X-ray, differential thermal, and chemical methods were used to study the clay fractions of soil samples from 21 localities in the Pampa region of eastern Argentina. A Pleistocene loesslike sediment consisting of eolian arkosic and pyroclastic silt is the principal parent material, and detrital illite is the p…
The problem of finding the equilibrium shape of a small particle by the Wulff construction is reviewed briefly, with emphasis on its applications to liquid crystals. The proof of Wulff's theorem is stated in a concise mathematical form. Some typical equilibrium shapes of liquid crystalline drops are described. When th…
Abstract The transformations of the polymorphic forms of polybutene‐1 (I,II,III) were studied by infrared spectroscopy. Attenuated total reflectance spectra demonstrate that the II → I transformation occurs initially and most rapidly on the film surfaces. Electron irradiation experiments showed the II → I conversion c…
Transmission electron microscope examinations of silicon single crystals, phosphorus-diffused at low temperatures from anodic oxide films as phosphorus sources, showed the presence of crystallographically oriented precipitate. X-ray and electron diffraction investigations of SiP and SiAs single crystals prepared by a…
Summary This paper presents a quantitative interpretation of results of differential thermal analysis of hydration reactions at 2, 12,23 and 52°C of 3CaO.Al 2 O 3 mixed with 0, 0·25, 2·5, 10 or 20% gypsum, and compares these with length changes obtained from the hydration of compacts of these mixtures. Estimates of th…
Abstract Di- and trioctahedral micas were altered to vermiculite-like minerals by extracting the K with sodium tetraphenylboron. Chemical analysis of original and altered micas shows that loss of K is accompanied by an increased loss on ignition, oxidation of some Fe 2+ to Fe 3+ , loss of divalent octahedral cations,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubstituted Deuteroporphyrins. II. Substituent Effects on Electronic Spectra, Nitrogen Basicities, and Ligand Affinities*Winslow S. Caughey, Wilfred Y. Fujimoto, and Barbara P. JohnsonCite this: Biochemistry 1966, 5, 12, 3830–3843Publication Date (Print):December 1, 1966Publ…
The stimulation of bacterial respiration by clay minerals was related to certain physicochemical characteristics of clays. Respiration increased with an increase in the cation exchange capacity and surface area of the particles. The importance of surface area, however, could not be unequivocally established, as some o…
The complexes formed by ethylene glycol, HOCH 2 .CH 2 OH, and by glycerol, HOCH 2 .CHOH.CH 2 OH, with smectites (montmorillonite-saponite group), and vermiculites have received more attention than any other group of organo-silicate complexes. This interest arose in the first place from their use for identification pur…
The boundaries of regions of glass‐forming compositions were determined in binary tellurite systems with alkali, alkaline‐earth, and heavy‐metal oxides, and in the ternary systems TeO 2 ‐WO 3 ‐Ta 2 O 5 , TeO 2 ‐WO 3 ‐BaO, TeO 2 ‐WO 3 ‐Bi 2 O 3 , and TeO 2 ‐WO 3 ‐Tl 2 O. On the basis of a structural interpretation of l…
We consider an M×N periodic system of hard squares each of which prohibits the occupation of its nearest-neighbor sites by the other squares. An appropriate unitary transformation factors the matrix required in evaluating the grand canonical partition function into a direct sum of submatrices. Each submatrix belongs t…
Abstract Thin films of phthalocyanine compounds formed on cleaved surfaces of muscovite by the vacuum-condensation method showed well-defined single-directional orientation when their substrates were preheated at 300°C for one hour and then kept at 150°C. Their electron diffraction patterns were fiber diagrams, the fi…