Materials Literature
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Abstract The cure of pyromellitic dianhydride–oxydianiline polyamic acid is compared with that of a model compound, diphenylcarbamido–dicarboxy–benzene, both having been synthesized in 1‐methyl‐2‐pyrrolidinone (NMP). Laser interferometry and thermogravimetric analysis showed that, analog to the diamic acid model compo…
The clustering of carbon in the detonation regime is studied with the assumption of a diffusion-limited clustering process. The diffusion constants are determined from modified Enskog theory and the Stokes–Einstein relation. With the size dependence of the cluster energy treated with a surface term, the energy differe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, characterization, and interconversion of the niobotungstic acid Nb2W4O19H3- and its anhydride and alkyl/silyl estersV. W. Day, W. G. Klemperer, and C. SchwartzCite this: J. Am. Chem. Soc. 1987, 109, 20, 6030–6044Publication Date (Print):September 1, 1987Publicatio…
The structures of phosphourus oxynitride glasses have been determined using a combination of solid‐state 31 P, 15 N, and 23 Na nuclear magnetic resonance and Raman spectroscopies. Raman spectra of model phosphazene compounds with different types of P–N bonding have been used to confirm spectral assignments. Results in…
These guidelines update and extend the charts and data summaries presented in an earlier work, Guidelines for Selection of Marine Materials, in which many of the copper alloys covered in this review were not included.
Solid state, variable temperature 15 N‐NMR studies make it possible to predict the behavior of the four N atoms and the two internal H atoms in the isomeric porphine and porphycene. The spectra of porphine indicate a statistical disorder of the internal H atoms. In the case of porphycene it can be concluded that there…
Abstract The reductive dissolution by Na-dithionite of 28 synthetic goethites and 26 hematites having widely different crystal morphologies, specific surfaces and aluminium substitution levels has been investigated. For both minerals the initial dissolution rate per unit of surface area decreased with aluminium substi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCP/MAS carbon-13 NMR spectra of the crystalline components of native cellulosesFumitaka Horii, Asako Hirai, and Ryozo KitamaruCite this: Macromolecules 1987, 20, 9, 2117–2120Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published ini…
The C KLL spectra from natural diamond, graphite, and single-crystal β-SiC have been investigated using x-ray photoelectron spectroscopy and first-derivative x-ray excited Auger electron spectroscopy (XAES). It is shown that the XAES spectra is essentially the same as that obtained with conventional AES with the added…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic interaction and spin transition in iron(II) dinuclear compounds. Crystal structure of (.mu.-2,2'-bipyrimidine)bis[(2,2'-bipyrimidine)bis(thiocyanato)iron(II)]Antonio Real, Jacqueline Zarembowitch, Olivier Kahn, and Xavier SolansCite this: Inorg. Chem. 1987, 26, 18,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface-enhanced Raman spectrometry of organo phosphorus chemical agentsAla M. Alak and Tuan. Vo-DinhCite this: Anal. Chem. 1987, 59, 17, 2149–2153Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https:…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotosensitized reduction of carbon dioxide to methane and hydrogen evolution in the presence of ruthenium and osmium colloids: strategies to design selectivity of products distributionItamar Willner, Ruben Maidan, Daphna Mandler, Heinz Duerr, Gisela Doerr, and Klaus Zengerl…
The title compound 1 and its nickel complex fulfill all that was hoped for: Substitution of porphycene with four propyl groups leads (as in the case of porphyrins) to increased solubility and crystallizability. 1 is distinguished by strong NH…N hydrogen bridges and by NH tautomerism. The nickel complex has the expect…
Abstract The liquid crystalline behavior of low molecular weight compounds has been known for more than a century; synthetic polymers have been manufactured on a large scale for several decades, but just recently it was found possible to produce polymers using the structural principles of liquid crystalline compounds.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and crystal structure of a novel tripyrrane-containing porphyrinogen-like macrocycleJonathan L. Sessler, Martin R. Johnson, and Vincent LynchCite this: J. Org. Chem. 1987, 52, 19, 4394–4397Publication Date (Print):September 1, 1987Publication History Published onli…
Abstract An improved method is presented for separating whole soil into a mineral‐free organic fraction (light fraction) and an organomineral fraction (heavy fraction) by flotation in a dense inorganic salt solution. In the existing method, the heavy fraction is settled by centrifugation and the light fraction decante…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new low-temperature route to metal polychalcogenides: solid-state synthesis of potassium titanium sulfide (K4Ti3S14), a novel one-dimensional compoundSteven A. Sunshine, Doris Kang, and James A. IbersCite this: J. Am. Chem. Soc. 1987, 109, 20, 6202–6204Publication Date (Pr…
The magnetic and structural properties of RTiFe ternary alloy system were investigated. It was found that the alloy includes a new compound having the ratio of R to Ti to Fe of 1:1:10 and tetragonal structure. The SmTiFe10compound has a high saturation magnetization and magnetic anisotropy. It was also found that the…
Dynamic and static properties of a polymer chain without self-excluded volume, which performs Brownian motion between randomly distributed impenetrable fixed obstacles, have been investigated by Monte Carlo simulations and analyzed by scaling considerations. The mean square radius of gyration 〈S2〉, the center-of-mass…
Abstract Anodic overoxidation of polypyrrole in the presence of nucleophiles such as H 2 O, OH − , CH 3 OH, CH 3 O − , Br − and CN − has been studied in detail. At potentials up to 2.1 V (vs. SCE), irreversible anodic peaks are observed with 200 nm layers on Pt. In most of the cases, a total of z = 4 – 6 F /mol monome…