Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTESR and ENDOR of pentacoordinated cobalt(II) porphyrinsG. P. Daeges and J. HuettermannCite this: J. Phys. Chem. 1992, 96, 12, 4787–4794Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https://pubs.acs.org/doi/10.…
To meet the future goals of reduced emissions produced by gas turbine combustors, a better understanding of the process of formation of various pollutants is required. Both empirical and analytical approaches are used to provide the exhaust concentrations of pollutants of interest such as NOx, CO, and unburned hydroca…
Concepts explaining the phenomena of diffuse ferroelectric phase transitions (DFPT's) are applied to PLZT ceramics. PZT ceramics, as the origin of PLZT, can be used to explain and predict some of the PLZT properties. The nature of characteristic temperatures Tm Td and Tf is discussed. Behaviour of the field and zero f…
Abstract The photophysical and redox properties of (2-substituted porphyrinato)zinc derivatives in various solvents are investigated. Zinc complexes of 2-bromo-, 2-cyano-, and 2,3-(l,4-phenylenedinitrilo)-substituted porphyrins as well as (tetraphenylporphyrinato)zinc (Zntpp(H,H)) exhibit well-resolved Q0,0 and Q0,1 f…
Mg-containing synthetic apatites were prepared and then incubated in unbuffered 0.9% NaCl solution and in buffered 0.1 M CH3COOK solution (pH 7.4) at 37 degrees C to examine the changes in their crystallographic and chemical properties after suspension in these solutions. After one month of incubation, the magnesium (…
Abstract Nonexchangeable polymers in interlayers of expansible phyllosilicates influence thermal dehydration in ways not completely understood. Thermal dehydration of hydroxy-interlayered vermiculite (HIV) from Florida soils, for example, results in irreversible d 001 shifts. This study was conducted to characterize H…
Atmospheric pressure tetraethyloxysilicane ( TEOS ) / O 3 chemically vapor deposited provides excellent step coverage for submicron device structures; however, the properties of the deposited films depend on the surface characteristics of the base materials being used. To illustrate this dependence, the deposition rat…
Abstract Zr-rich pyrochlore crystals in carbonatite from San Vicente (Cape Verdes Islands) show cryptic, concentric and rhythmic chemical zonation with Ca increasing and Ti, U and Zr decreasing towards the rims. In one carbonatite, taken from the Camile dyke, previously undocumented cryptic sector zonation of Ti, U an…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of a new family of poly(ortho esters)J. Heller, S. Y. Ng, and B. K. FritzingerCite this: Macromolecules 1992, 25, 13, 3362–3364Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https…
In systems like glass-forming melts in the vicinity of the vitrification temperature or polymers, the elastic strains which evolve as a result of formation and growth of an ensemble of clusters may result in a partial or total inhibition of cluster growth and Ostwald ripening already in the absence of elastic interact…
Syndiotactic polystyrene (sPS) films were obtained either by casting or by melt crystallization in the β form. Different thermal treatments of the melt led to mixed α and β forms. The structural organization was investigated by x-rays, transport properties, and Fourier transform infrared analysis. The β form is charac…
A computationally simple, but accurate, model for porphyrin ring-current shifts is presented and calibrated by using X-ray and n.m.r. data from cytochrome c, cytochrome C551, cytochrome b 5, and pyridine and picoline complexes of zinc porphyrin . The model involves a multipole expansion in terms of Legendre polynomial…
Abstract X‐ray photoelectron spectroscopy and cyclic voltammetry have been used to characterize 4.9 wt.% platinum‐on‐graphite catalysts used for the oxidation with molecular oxygen of methyl α‐ D ‐glucoside in aqueous solution. Cyclic voltammetry indicates that a surface oxidic layer is formed on the platinum particle…
Abstract The structure of a disordered II b Mg-chamosite was studied using Rietveld refinement techniques and powder X-ray diffraction (CuK α , 18–120° 2 θ in 0.02° 2 θ increments). The refinement in space group CĪ yielded high precision lattice parameters (a = 5.36982(5)Å, b = 9.3031(9)Å, c = 14.2610(6)Å, α = 90.315(…
Abstract A new method for coating the inner surface of ultrahigh‐vacuum (UHV) vessels with an inert material is proposed, namely coating with highly oriented graphite layers which precipitate on the surface of a carbon‐doped nickel substrate. By using various surface analytical methods, characterization of the precipi…
NOx exhaust emissions for gas turbine engines with lean-premixed combustors are examined as a function of combustor pressure (P), mean residence time (τ), fuel-air equivalence ratio (φ), and inlet mixture temperature (Ti). The fuel is methane. The study is accomplished through chemical reactor modeling of the combusto…
The charge behavior in an organic photoconductor (OPC), which can be used as an electrophotographic receptor, was observed using the pressure wave propagation method. When a pulse pressure wave passes through the sample, a displacement current is generated. The charge distribution is obtained from the measurement of t…
With application in infrared lenses , lanthanum sulphide and calcium lanthanum sulphide are ceramic materials which require a low defect density in order to minimize light scattering and maximize mechanical strength. Solution routes to monodispersed ceramics are investigated, offering materials with improved packing i…
Partial discharge (PD) detection for live UHV/EHV power cables and accessories is the most important test on cable systems, to prevent problems caused by minor mistakes in jointing the cable. A new PD detecting method is proposed. A REDI (resonance type partial discharge) sensor was developed for detecting PD occurrin…
Plate impact experiments are conducted to study the dynamic fracture processes which occur on submicrosecond time scales. These experiments involve the plane strain loading of a plane crack by a square tensile pulse with a duration of approximately one microsecond. The crack-tip loading rates achieved are K1 ˜ 108MPam…