Materials Literature
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This paper describes the study of the reliability of capacitor units installed and operated in a distribution system during the period 1980 through 1990. Failures of capacitor units in distribution substations can be very costly to the supply of reliable power to consumers. To enhance utility reliability, failure anal…
The compound Li 4 GeS 4 has been prepared as transparent, light yellow moisture-sensitive crystals. Li 4 GeS 4 belongs to the space group Pnma with a = 14.107(6) Å, b = 7.770(3) Å and c = 6.162(2) Å. The crystal structure was solved by direct-methods. The final R and R w -values are 1.85 and 1.65% for 866 observed ref…
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In most types of high voltage apparatus, a PD acceptance test is required. In contrast, the PD test is very rarely used as an acceptance test for new motor and generator windings. The closest that machine manufacturers come to a PD acceptance test is the power factor tip-up test (IEEE Standard 286), which is an indire…
A brief review is given of ferroelectric thin-film memory technology, emphasizing up-to-date comparisons among different materials, including lead zirconate-titanate (PZT), barium-strontium titanate (BST), and strontium bismuth tantalate (SBT) for both DRAMS and non-volatile RAMS.
A dioxoruthenium(VI) complex containing a D4-porphyrinato ligand por* {H2por* = 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4∶5,8-dimethanoanthracen-9-yl]porphyrin} has been prepared by oxidation of its ruthenium(II) carbonyl precursor with m-chloroperoxybenzoic acid and characterised by spectroscopi…
Hybrid organic–inorganic materials have been prepared from mixtures of tetraethoxysilane and poly(ethylene glycol) (PEG) of low molecular mass. These materials are diphasic systems in which silica aggregates, controlling the mechanical properties, are wrapped around by the polymer phase. Strong correlations between th…
The detailed understanding of the magnetic properties of transition-metal multilayers requires the use of state-of-the-art experimental techniques. Over the last few years, the X-ray magnetic circular dichroism (XMCD) technique has evolved into an important magnetometry tool. This paper is an overview of the principle…
Two different methods to adaptively refine tetrahedral finite element meshes are presented. The influence of the mesh refinement on the obtained results of micromagnetic calculations is demonstrated for the case of magnetization patterns in soft magnetic platelets. The specific addition of vertices and finite elements…
The measurement of partial discharge(PD) of several faults in gas-insulated system (GIS) is discussed. Phase-resolved PD patterns have been measured using three different PD detection measuring systems: according to the IEC 270 recommendations, a VHF/UHF measuring system with narrow band filtering, and the UHF measuri…
The enzymatic activity of phosphoglycerate mutase (Pgm) from three gram-positive endospore-forming bacteria (Bacillus subtilis, Clostridium perfringens, and Sporosarcina ureae) requires Mn2+ and is very sensitive to pH; at low concentrations of Mn2+, a pH change from 8 to 6 resulted in greater than 30- to 200-fold dec…
The advent of stricter U.S. and European exhaust emissions regulations has increased the need for reliable 3-way catalytic converter models supporting the design of demanding exhaust systems for low-emitting vehicles. Although a number of tunable models have been presented in the literature, their efficient performanc…
The interaction between the calcite cleavage plane surface and three different diphosphonate molecules has been studied employing methods based on interatomic potentials. The diphosphonates studied include 1-hydroxyethylidene-1,1-diphosphonate (HEDP) (which is known empirically to poison crystal growth) together with…
Push-pull substituted nonlinear optical chromophores with thiazole and thiophene rings and interposed ethylene units as π-conjugated bridges were synthesized. The effects of the nature and location of the heterocycles on the energy of the charge transfer transition for the chromophores are discussed.
Ordered layered three-dimensional networks of Au, Ag and Au/Ag colloids are assembled in a stepwise synthesis using N,N′-bis(2-aminoethyl)-4,4′-bipyridinium as a redox-active crosslinker.
The object of this project was to study the influence of temperature and water vapor pressure on the kinetics and mechanism of dehydration of carbamazepine dihydrate and to establish the relationship between the dehydration mechanism and the solid-state of the anhydrous phase formed. Three experimental techniques were…
Treatment of benzocarbaporphyrin 2 with refluxing FeCl3 in CHCl3–alcohol mixtures leads to a remarkably selective oxidation at the interior carbon atom to produce dialkoxy products 5; these species show potentially valuable long wavelength absorptions in their UV–VIS spectra.
Phenyl-modified porous silicas have been synthesized at room temperature by the co-condensation of a siloxane and an organosiloxane in the presence of a surfactant. Mesitylene was employed as a pore swelling agent to produce a mesostructured material. The product has been characterized by powder XRD, nitrogen sorption…
We report on light-induced linear and second- and third-order nonlinear optical effects in high-glass-transition-temperature (Tg) photosensitive nonlinear optical azo polyimides. We present evidence of light-induced orientation of azo chromophores at room temperature in very high-Tg polyimides (Tg up to 350 °C) even t…
Double-mesopore silica with a characteristic N2 adsorption isotherm and narrow bimodal mesopore distribution is synthesized rapidly at room temperature by using aqueous ammonia as the catalyst.