Materials Literature
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A family of phosphate glasses has been developed with thermal expansion behavior in the elastic range that nearly matches the response of 304 stainless steel. Attempts to make concentric pin‐shell seals consistently have yielded fractures between 400° and 300°C during cooling. Elastic stress analyses which neglect gla…
Abstract The molecular weight dependence of the glass transition temperatures of polystyrene, polyα‐methyl styrene, polyisopropylα‐methyl styrene, polymethylmethacrylate, polyvinylchloride, poly‐isobutylene, polyisoprene, and poly‐ N ‐octadecylmaleimide is described by an equation developed from the Principle of Corre…
Abstract EXAFS (Extended X-ray Absorption Fine Structure) experiments on various polynuclear molybdate and tungstate compounds revealed the unusual phenomenon that Mo–O peaks which should appear at around 1.9 Å in Fourier transforms of the EXAFS spectra for Mo6O192− and PMo12O403− are hardly discernible, while the tun…
A parametric interpretation of the fine and hyperfine structures is given for all the experimental even levels of singly ionised praseodymium on the basis of the 3 mixed configurations 4 f 2 5 d 2 + 4 f 2 5 d 6 s + 4 f 3 6 p . The experimental energies of 187 levels are interpreted with 50 parameters (43 free paramete…
Upon lowering the temperature below 450 K the superionic solid Ag2 S undergoes a structural phase transformation from a bcc sulfur lattice with the space group Im3m to a monoclinic lattice with the space group P21 /c. We have successfully modeled this transformation using the variable size–shape form of molecular dyna…
Abstract Measurements of chemiluminescence (CL) during heating of nitrate esters (PETN and NC) have been conducted in the temperature range between 40 °C and 90 °C in an inert atmosphere. Faint light was emitted from the condensed‐phase in steady‐state fashion. This new finding implies that the thermal decomposition o…
Etude par diffraction RX de l'intervalle de composition, des parametres cristallins et de l'ordre des ions baryum dans le compose Ba x (Mg x Ti 8-x )O 16 . Determination par diffraction des neutrons de la structure pour x=1.14, 1.33, 1.20. Cristallisation dans I2/m avec affinement jusqu'a 0.018 pour les deux premieres…
SUMMARY This work aims to clarify the problem of why the ultimate resolution assessed experimentally from the observation of 0.8 nm separation of Au‐Pd fine particles is beyond the theoretical resolution limit of scanning electron microscopy (SEM). The correlation between the spatial distribution of secondary electron…
Abstract A method of obtaining modified amine curing agents containing β‐hydroxyurethane linkages is presented. The basic physical and chemical properties of the modified polyamines, such as viscosity and reactivity towards epoxy resins, have been studied. A shortening of the gel and curing times in addition to a decr…
The wide-angle X-ray diffraction patterns of carbon fibres are strongly modulated by disorder in the stacking of carbon layers, preferred orientation and the measuring conditions. A method has been developed to characterize the crystallites in carbon fibres by applying the theory on the wide-angle X-ray diffraction of…
Abstract The preparation and properties of highly crystalline ionomers formed by the copolymerization of propylene and low levels of ethylcholoroaluminium 10‐undecenoate have been investigated. Few of the variables studied had dramatic effects on the copolymerization. Thus, a five‐fold increase in undecenoate concentr…
Work on charge storage processes in dielectrics performed over the past few years is reviewed. Results obtained on polymers with corona, electron-beam, and pressure-pulse methods and pertaining to trap filling, spatial distribution of the charge, radiation-induced conductivity, and dynamics of the charge decay are dis…
In 0.5[xPZ-(1-x)PT]-0.5[yPZN-(1-y)PNN] system ceramics, the dielectric and piezoelectric properties, the temperature and electric field dependences have been studied as a function of PT and PZN content. In both calcined powders and fired samples with the addition of columbite precursor materials, a presence of the pyr…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOptical versus thermal electron transfer between iridium(I) maleonitriledithiolate complexes and methyl viologenElise Graham Megehee, Curtis E. Johnson, and Richard EisenbergCite this: Inorg. Chem. 1989, 28, 12, 2423–2431Publication Date (Print):June 1, 1989Publication Histo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemistry of nickel picket fence porphyrin. Electrogeneration and spectral characterization of nickel complexes in unusual oxidation statesK. M. Kadish, D. Sazou, G. B. Maiya, B. C. Han, Y. M. Liu, A. Saoiabi, M. Ferhat, and R. GuilardCite this: Inorg. Chem. 1989, 28,…
A new indole alkaloid glucoside, named palicoside, has been isolated from the leaves of PALICOUREA MARCGRAVII (Rubiaceae) collected in Brazil. The structure was established by spectroscopic methods and its chemical conversion to strictosamide.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolythioamide and poly(1,3,4-thiadiazole) synthesis from dimethyl tetrathioterephthalateIsabelle Delfanne and Guy LevesqueCite this: Macromolecules 1989, 22, 6, 2589–2592Publication Date (Print):June 1, 1989Publication History Published online1 May 2002Published inissue 1 Ju…
Compared with wood pulp cellulose, alkaline H2O2-treated wheat straw [suitable for incorporation into baked foods, to reduce caloric density and increase dietary fibre levels] becomes more extensively hydrated, increases more in size when hydrated, and contains a larger glucose accessible internal vol. These and other…
Three different binuclear phthalocyanines were prepared and characterized. Two of the binuclear phthalocyanines are cofacially linked by rigid naphthalene and anthracene spacers, while the third consists of a direct linkage between two phthalocyanine rings. The dicobalt, dicopper, and dizinc derivatives were prepared…
The adsorption of CO2 on clean silver films, oxygen treated silver films and alkali metal predosed silver films has been studied with surface enhanced Raman spectroscopy (SERS) and work function measurements. At 50 K, CO2 was observed to adsorb on vapor deposited silver films with downward vibrational frequency shifts…