Materials Literature
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We examined a rhyolitic volcanic ash bed deposited 20000 years ago in different leaching environments in New Zealand. When winter leaching was greater than 250 mm a year, the ash contained 10 to 15% allophane; as leaching increased from 250 to 600 mm a year, the A1/Si ratio of the allophane increased from 1.2 to 2.0.…
The etch rate of in solutions of high concentration was shown to be independent of the applied potential in a wide potential range negative with respect to the flatband value. Dissolution of the solid led to the formation of . The etch rate, which was not mass‐transport controlled, was first order in molecular concent…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAb initio direct calculation of the singlet-triplet splitting in a .mu.-oxalato copper(II) binuclear complexM. F. Charlot, M. Verdaguer, Y. Journaux, P. De Loth, and J. P. DaudeyCite this: Inorg. Chem. 1984, 23, 23, 3802–3808Publication Date (Print):November 1, 1984Publicati…
When plasticized PVC packagings are put into contact with liquids (blood, food), a migration of plasticizer and additives may occur, being responsible for a contamination of the liquid and a decrease in the mechanical properties of polymer. The interest in short tests is especially pointed out. In contrast to classica…
The study of recombination lifetimes and kinetics is an essential part of the analysis of recombination mechanisms in semiconductors. In recent years, time-resolved spectroscopy (TRS) has become the standard method of obtaining such experimental data, using a pulsed excitation source and gated detection. In this paper…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTViscoelastic properties and relaxation mechanisms of binary blends of narrow molecular weight distribution polystyrenesHiroshi Watanabe and Tadao KotakaCite this: Macromolecules 1984, 17, 11, 2316–2325Publication Date (Print):November 1, 1984Publication History Published onl…
Abstract The compatibility of poly(ethylene oxide)‐poly(methyl methacrylate) (PEO‐PMMA) blends were examined covering the complete composition range. Up to 20% of PEO content films were transparent and glass transition temperatures were determined by DSC and by refractive index vs. temperature measurements. Only one T…
SUMMARY Backscattered and secondary electrons are both used in the SEM for imaging purposes. The backscattered signal is the result of high angle elastic scattering events, while the secondary signal is the result of knock‐on inelastic collisions. The characteristic differences between images in the two modes arise fr…
Abstract Copper forms passivating layers in alkaline solutions. Depending on the electrode potential a Cu 2 O or a Cu 2 O/CuO, Cu(OH) 2 layer is present. The structure and composition of the film has been examined by different methods like X‐ray Photoelectron Spectroscopy (XPS), Ion Scattering Spectroscopy (ISS) and i…
This work had three objectives: to improve the reported assignments of the vibrational frequencies in several organoslllcon monomers and oligomers; to assign the vibrational frequencies of polydimethylsiloxane (PDMS); and to relate the vibrational spectra of PDMS to its other physical properties, especially at sub-amb…
Based on the two-band imperfect-nesting model within the mean-field approximation, the incommensurate spin-density wave (ISDW) is investigated theoretically. Taking into account infinite numbers of higher harmonics, we obtain an exact solution under the assumptions that the electron dispersion relation is linearized n…
The microstructure of thin films applied by conventional physical vapor deposition for use as optical coatings is columnar for most of the materials commonly used. This has been established for about a decade through numerous experimental observations employing microfractographical replication for use with high resolu…
The organic matrix of calcium carbonate structures can be involved in the formation of the biomineral by regulating various stages of crystal growth. The preponderance of evidence suggests that matrix can act as an initiator of crystal growth at the mineralizing front. The mechanism for this initiation is not known. H…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModels of the cytochromes b. 5. EPR studies of low-spin iron(III) tetraphenylporphyrinsF. Ann Walker, David Reis, and Virginia L. BalkeCite this: J. Am. Chem. Soc. 1984, 106, 23, 6888–6898Publication Date (Print):November 1, 1984Publication History Published online1 May 2002…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModels of oxidized heme proteins. Preparation and characterization of a trans-dioxoruthenium(VI) porphyrin complexJohn T. Groves and Robert QuinnCite this: Inorg. Chem. 1984, 23, 24, 3844–3846Publication Date (Print):November 1, 1984Publication History Published online1 May…
Boehmite sol‐gels were seeded by adding <2.0 wt%α‐alumina powder to a 20% boehmite hydrosol at pH =3. The seeded gel sintered to 98% of theoretical density after 100 min at 1200°C, whereas the unseeded gel had to be sintered at 1600°C to reach 94% of theoretical density. This difference results primarily from nucle…
Abstract Die Darstellung und Strukturuntersuchung von Sr 3 Fe 2 O 5 Cl 2 wird beschrieben. Diese Verbindung gehört zum Sr 3 Ti 2 O 7 ‐Typ mit a = 3,942(2) und c = 23,786(12) Å; Raumgruppe D −I4/mmm. Sr 3 Fe 2 O 5 Cl 2 besitzt einseitig gestreckte FeO 5 Cl‐Oktaeder, die in bezug zu anderen K 2 NiF 4 ‐Strukturen diskuti…
Si, Ge and Sn have been studied by energy dispersive X-ray diffraction up to 50 GPa. Si shows first the well known transition from diamond to β-tin structure around 11 GPa. It transforms to a primitive hexagonal structure (Si-V) around 15 GPa, to an intermediate phase Si-VI around 35 GPa and finally to hcp (Si-VII) ar…
Non-geometric high dielectric constant stress relef has been used successfully since the 1960' s for terminating shielded power cable primarily in tape form. Unique problems occurred when adapting the early tape form of this technology to formulate high dielectric constant elastomers which could be molded or extruded.…
Abstract In an attempt to compare the relative reactivities of different redox systems in graft copolymerization of vinyl monomers onto cellulose, we studied grafting of ethylacrylate (EA) in aqueous medium by using the well‐known redox intiator, ferrous ammonium sulfate–potassium persulfate (FAS–KPS) system, and its…