Multiple-foci Luneburg lenses
A family of variable-index spherically symmetric lenses is presented that provide the light focusing at two (or three) points, subject to an appropriate division of the aperture.
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Mechanical analysis of elastomeric seals by numerical methods
A procedure which permits the evaluation of the stress-strain field in an elastomeric seal is presented. Such a procedure is based upon a mechanical modeling of the elastomer and on the employ of finite elements which can cope with high strains. Finally, the above-mentioned procedure is checked against experimental re…
Single-crystal EPR spectra of tetra-n-butylammonium bis(isotrithione-3,4-dithiolato)cuprate(II) (copper-63)
ADVERTISEMENT RETURN TO ISSUEPREVArticleSingle-crystal EPR spectra of tetra-n-butylammonium bis(isotrithione-3,4-dithiolato)cuprate(II) (copper-63)Joachim Stach, Reinhard Kirmse, Wolfgang Dietzsch, Ruth Maria Olk, and Eberhard HoyerCite this: Inorg. Chem. 1984, 23, 26, 4779–4780Publication Date (Print):December 1, 198…
The solubility of 17 β-oestradiol in aqueous polyethylene glycol 400
The solubility of 17 beta-oestradiol (E2) in aqueous solutions of polyethylene glycol (PEG) 400 has been measured at 35 degrees C. Up to 80% w/w PEG the solubility data conform to a log linear equation ln S = ln Sw + f sigma where S is the E2 concentration in the water/cosolvent mixture, Sw is E2 solubility in water,…
Magnetic order or charge-density wave inLa2NiO4by Mössbauer spectroscopy
Measurements of Mössbauer absorption spectra of 57 Fe : La 2 Ni O 4 at 297, 77, and 4.2 K provide evidence, at the lowest temperatures, of magnetic order in a sample containing 57 Fe 3 + -ion impurities and some La 2 + n Ni 1 + n O 4 + 3 n intergrowth. Mössbauer emission spectra of 57 Co : La 2 Ni O 4 at 77 and 4.2 K…
Byproduct identification in the terephthalic acid production process and possible mechanisms of their formation
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTByproduct identification in the terephthalic acid production process and possible mechanisms of their formationPaolo Roffia, Pierangelo Calini, Luigi Motta, and Sergio TontiCite this: Ind. Eng. Chem. Prod. Res. Dev. 1984, 23, 4, 629–634Publication Date (Print):December 1, 19…
Experimental test of the bremsstrahlung cross section
The bremsstrahlung cross section has been studied by measuring the activity induced in $^{63}\mathrm{Cu}$ by electrodisintegration and when thin radiators of Cu, Mo, Ta, and Th were placed in the electron beam just ahead of the target. The electron energies were varied from 13.5 to 60 MeV for the electrodisintegration…
Surface modification and grafting of natural and synthetic fibres and fabrics under cold plasma conditions
Natural and synthetic fibres and fabrics have been modified in cold plasma conditions in order to impart new qualities to support materials. Both static and dynamic installations designed to this aim are presented. Improved hydrophilicity, dyeability and flamme retardancy properties were achieved by grafting with eith…
Mechanistic Studies with Mass Spectroscopic Cyclic Voltammetry: Anodic Oxidation of Hydroxylamine on Pt
Abstract The anodic oxidation of NH 2 OH on Pt in neutral and acid solutions was studied using CV, RRDE and Mass Spectroscopic Cyclic Voltammetry. Thus, the i /ϕ‐curves obtained could be correlated to the rates of formation of the gaseous products N 2 , N 2 O t NO and NO 2 . Three anodic waves were distinguished, each…
STRUCTURE, LIFE HISTORY AND SYSTEMATICS OF RHOICOSPHENIA (BACILLARIOPHYTA). V. INITIAL CELL AND SIZE REDUCTION IN RH. CURVATA AND A DESCRIPTION OF THE RHOICOSPHENIACEAE FAM. NOV.1
ABSTRACT The initial epivalve of Rhoicosphenia curvata (Kütz.) Grun. differs from vegetative valves in having a strongly arched section, a wide hyaline marginal strip, no pseudosepta, an unthickened margin, and a terminal raphe fissure at the head pole. The initial epivalve is of the D type, with short raphe fissures.…
X-ray and neutron diffraction study of [P(CH2C6H5)(C6H5)3]+[HIr4(CO)11]-
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray and neutron diffraction study of [P(CH2C6H5)(C6H5)3]+[HIr4(CO)11]-Robert Bau, Michael Y. Chiang, Chiau Yu Wei, Luigi Garlaschelli, Secondo Martinengo, and Thomas F. KoetzleCite this: Inorg. Chem. 1984, 23, 26, 4758–4762Publication Date (Print):December 1, 1984Publicati…
EXAFS analysis of the structure of ionomer microdomains
Abstract Extended x‐ray absorption fine‐structure (EXAFS) measurements were used to determine the near‐neighbor environment of the neutralizing cation in several ionomer system. The observed structure is compared to that existing in analogous low‐molecular‐weight crystalline salts. A wide variety in the degree of loca…
Cofacial assembly of partially oxidized metallomacrocycles as an approach to controlling lattice architecture in low-dimensional molecular solids. Synthesis and properties of cofacially joined silicon and germanium hemiporphyrazine polymers
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCofacial assembly of partially oxidized metallomacrocycles as an approach to controlling lattice architecture in low-dimensional molecular solids. Synthesis and properties of cofacially joined silicon and germanium hemiporphyrazine polymersCarl W. Dirk and Tobin J. MarksCite…
Sonolysis of Chloroform
Abstract Chloroform is decomposed by irradiation with ultrasonic waves to yield a large number of products. The major products are various unsaturated compounds. Decomposition occurs only in the presence of a monoatomic‐ or diatomic gas. Free radicals and carbenes are postulated as intermediates of sonolysis which can…
Model calculations for the intensity parameters of nine-coordinate neodymium(III) and holmium(III) complexes of trigonal symmetry
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModel calculations for the intensity parameters of nine-coordinate neodymium(III) and holmium(III) complexes of trigonal symmetryEileen M. Stephens, Michael F. Reid, and F. S. RichardsonCite this: Inorg. Chem. 1984, 23, 26, 4611–4618Publication Date (Print):December 1, 1984P…
Molecular Vibration Analysis of lonicity and Phase Transition in TMPD-TCNQ (1:1) Charge Transfer Salt
The infrared spectra of the (1:1) charge transfer salt of N, N, N′, N ‘-tetramethyl-p-phenylendiamine (TMPD) with 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ) and with fully deuterated TCNQ are reported. The assignment of the vibrational data is obtained on the basis of the comparison with that of neutral and ionized pa…
The NMR spectra of porphyrins. 27—proton NMR spectra of chlorophyll‐a and pheophytin‐a
Abstract The 500 MHz proton NMR spectra of chlorophyll‐ a in several non‐aggregating solvents, at high dilution, are given and that of pheophytin‐ a in CDCl 3 at 360 MHz and at high dilution is reported. Under these conditions, the dispersion is such that separate resonances are observed and can be assigned for all pr…
Water‐soluble copolymers. IX. Copolymers of acrylamide with N‐(1,1‐dimethyl‐3‐oxybutyl)acrylamide and N,N‐dimethylacrylamide: Synthesis and characterization
Abstract The copolymerizations of acrylamide (AM) with N ‐(1,1‐dimethyl‐3‐oxybutyl)acrylamide (DAAM) and with N , N ‐dimethylacrylamide (DMAM) have been studied. The values of r 1 , r 2 have been determined to be 0.75 for the AM‐DAAM pair and 0.86 for the AM‐DMAM pair. The molecular weights of the copolymers were foun…
Electrode Kinetics of Fuel Oxidation at Copper in Molten Carbonate
Copper appears to be a promising anode material for the molten carbonate fuel cell, as an alternative to nickel. Therefore, polarization data have been obtained for oxidation of fuel gases on a fully immersed copper rod. The electrode‐kinetic parameters have been determined using the potential‐step technique. The reac…
Chain-folding initiation structures in ribonuclease A: conformational free energy calculations on Ac-Asn-Pro-Tyr-NHMe, Ac-Tyr-Pro-Asn-NHMe, and related peptides
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChain-folding initiation structures in ribonuclease A: conformational free energy calculations on Ac-Asn-Pro-Tyr-NHMe, Ac-Tyr-Pro-Asn-NHMe, and related peptidesM. Oka, G. T. Montelione, and H. A. ScheragaCite this: J. Am. Chem. Soc. 1984, 106, 25, 7946–7958Publication Date (…