Materials Literature
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Abstract The results described herein demonstrate the advantages of functionalized initiators with respect to the efficiency of α-chain-end functionalization and the ability to effect post-polymerization functionalization and linking reactions with the living ω-carbanionic chain ends. Not all functionalized initiators…
Transition metal oxides are important materials in heterogenous catalysis, as supporting materials as well as active components. The catalytic activity of Cr2O3 for IE polymerization of olefines or hydrogenation of alkenes is well known and rather high. Therefore, it is important to get information on the surface elec…
The disappearance of the boroxol rings has been identified as the microscopic structural change which occurs in a-${\mathrm{B}}_{2}$${\mathrm{O}}_{3}$ upon pressure induced densification. Although changes in ``ring statistics'' is often assumed to be responsible for densification, our results provide the first unambig…
Abstract A new constitutive model for the nonlinear behavior of noncrosslinked polymers with infinitesimal strains is derived. It generalizes a model of adaptive links for the viscoelastic behavior of crosslinked polymers. According to the model, a viscoelastic medium is treated as a set of elastic springs that replac…
Abstract Grünes Di(phthalocyaninato)lanthanid(III), [M(Pc) 2 ] (M = Lanthanid‐Ion: La‥(‐Ce, Pm)‥Lu) wird durch elektrochemische Oxydation von ( n Bu 4 N)[M(Pc 2− ) 2 ] in CH 2 Cl 2 /( n Bu 4 N)ClO 4 dargestellt. In den UV‐Vis‐NIR‐Spektren treten die für den Pc 2− ‐Liganden typischen π‐π*‐Übergänge bei ca. 15000 cm −1…
The plastic flow behavior of wrought Co-27Cr-5Mo-0.05C alloy was investigated at 298 K as a function of grain size using uniaxial tension testing. The microstructures produced by deformation were characterized using X-ray diffraction, reflected light, and scanning electron microscopy. This study revealed that material…
Experimental data suggest that NOM promotes the formation of pits in a certain narrow range of concentrations and suppresses this type of corrosion at higher dosages. Natural organic matter (NOM) profoundly affected the corrosion of copper in a moderately alkaline synthetic water. It decreased the rate of corrosion, i…
A quick, cheap and simple method of mixing liquid binding agents with rock powder to produce powder pellets suitable for x-ray fluorescence analysis is described. The preparation and use of a polyvinylpyrrolidone–methylcellulose-based liquid binding agent is also described.
Birefringence is caused by orientation of polymer chains during injection molding or extrusion, and is a large obstacle to optical applications. Transparent zero-birefringence copolymers were successfully synthesized by randomly copolymerizing two monomers having positive and negative birefringence, respectively. Sinc…
Open-cell foams have been transformed in prior studies, to a re-entrant (inward bulging) cell structure which gives rise to a negative Poisson's ratio. Different methods were used for polymer foams with and without a softening point. In this study, methods based on air pressure were developed for the transformation of…
Abstract Im System Zn/Mo/O sind mehrere ternäre Phasen bekannt. Bei 900°C sind die Phasen ZnMoO 4 , Zn 2 Mo 3 O 8 und Zn 3 Mo 2 O 9 stabil. Die Koexistenzgebiete sind am ternären Phasendiagramm dargestellt. Die Strukturbestimmung von Zn 3 Mo 2 O 9 erfolgte mit Röntgenbeugung an Einkristallen. Die Verbindung kristallis…
Strength measurements and fractography were used to investigate the failure of alumina‐glass dental composites containing 75 vol% alumina and 25 vol% glass. Alumina compacts were prepared by slip casting and sintering at 1100°C for 2 h. Dense composites were made by infiltrating partially sintered alumina with glass a…
High concentrations of total barium, ranging from 0.42 to 1.58 mg(middot)g(sup-1) (dry weight) were found in sludges of two sewage treatment plants near Florence, Italy. Barium concentrations in the suspended matter decreased as redox potential values changed from negative to positive. An anoxic sewage sludge sample w…
The structural, optical and related properties (i.e. photoluminescence, photoconductivity etc) of some synthetic (i.e. unconventional) three- and lower-dimensional semiconductor systems, which are based on inorganic units (:metal-halides, metal-chalcogenides etc), are briefly reviewed and some new results are reported…
Transition metal oxides are often used as the active components in heterogenous catalysis. Therefore the investigation of single crystal oxides as model systems is important to understand the reaction mechanisms on a microscopic level. The reactivity of a (111) surface of ionic rocksalt type structures seems to be rat…
This paper summarizes the Electricite de France experience with insulation coordination of gas-insulated substations (GIS). After a review of the insulation coordination practice, mainly dealing with fast front overvoltages and the one minute AC test, some results of the on-site test procedure applied for 30 years are…
Detailed theoretical studies of the temperature dependence of the zero-field splitting [characterized by \ensuremath{\Delta}D(T)=D(T)-D(0) or dD/dT] of ruby have been made by taking into account both the static contribution due to the thermal expansion of the lattice and the vibrational contribution due to the electro…
Abstract Cooling‐rate effects play an important role in polymer processing because the materials experience rapid cooling when transferring from melt states to solid states. The traditional Tait equation has been used widely in representing the volumetric behaviors of polymers as a function of temperature and pressure…
This study investigates a partial or complete replacement of synthetic sorbents by various biodegradable, natural sorbent materials. The sorbents examined are cotton, milkweed, kapok, wool, and kenaf fibers. It was found that (with the exception of kenaf) the oil sorption capacities of these natural sorbents (as loose…
The molten salt ${3\mathrm{K}\mathrm{N}\mathrm{O}}_{3}$-2Ca(${\mathrm{NO}}_{3}$${)}_{2}$ has been studied in the frequency range 5 mHz40 GHz and for temperatures 10 KT500 K using impedance spectroscopy. It is found that in the microwave regime the dynamic conductivity traces the primary response. In the radio- and aud…