Materials Literature
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The successful use of dipyrromethanecarbinols in rational routes to porphyrinic macrocycles requires catalysis conditions that enable irreversible condensation, thereby avoiding substituent scrambling and formation of undesired porphyrin products. Previously, successful conditions of trifluoroacetic acid (TFA) (30 mM)…
A model for the population dynamics of Er3+ in tellurite glasses with high erbium concentrations is proposed. Luminescence decay curves from transitions of 4I13/2→4I15/2 and 4S3/2→4I15/2 were measured experimentally. Upconversion coefficients were obtained by numerically solving the rate equations of the model to fit…
Monazite was continuously coated onto Nextel 720 fibers, using an aqueous precursor and in‐line heat treatment at 900°–1300°C. Some experiments were repeated with alumina‐doped precursors. Coated fibers were heat‐treated for 100 h at 1200°C. Coatings were characterized by optical microscopy, scanning electron microsco…
Washed and unwashed rhabdophane (LaPO 4 · x H 2 O) sols were used to apply monazite coatings to 3M Nextel 720 and 610 fibers. This precursor was designed to minimize stress corrosion from gaseous decomposition products at high temperature. The coatings were heat‐treated in‐line at 900°–1300°C, in air, using a continuo…
We have fabricated epitaxial thin films of the relaxor Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) and multilayer structures of relaxor/ferroelectric Pb(Mg 1/3 Nb 2/3 )O 3 /PbTiO 3 (PMN/PTO) using pulsed laser deposition. We present results obtained using reflection high energy electron diffraction (RHEED), x-ray diffraction (XRD) an…
This work deals with the factors affecting the reactivity of the CaO-SiO2-Al2O3-Fe2O3 mixture. Especially, the effect of the mixture's fineness and the effect of various additives are studied. Two groups of samples were studied. The first one consisted of limestone and clay mixtures having the same chemical compositio…
Bimetallic alloys have been considered in terms of their wetting behavior on semiconducting BaTiO3. In an earlier study, wetting behavior was strongly linked to ohmic contact behavior. However, the wetting behavior does not always correlate in the form of high work of adhesion-low contact resistance. The departure fro…
The anhydrous acid strontium oxalate Sr(HC 2 O 4 )⋅½(C 2 O 4 ) was obtained by thermal decomposition of the hydrated acid strontium oxalate Sr(HC 2 O 4 )⋅½(C 2 O 4 )⋅H 2 O. This non-hygroscopic compound crystallizes in the space group P 2 1 / c (No. 14) with unit cell parameters: a =0.796 61(7) nm, b =0.9205(1) nm, c…
The interaction of reduced transition-metal porphyrins [e.g. PMn (II), PFe (II), PCo (II)] with oxygen species (· O 2 ·, H 2 + O ·/ HO ·, HOO ·, · O ·) involves radical/radical coupling to form covalent bonds. Coordinately unsaturated iron(II) porphyrins form two sigma bonds with · O 2 ·(-Δ G BF = 1–6 kcal mol -1 ) vi…
Homogeneous mixtures of nanocrystalline powders of NiO-YSZ were obtained by combustion synthesis, and used to prepare cermet/YSZ/cermet symmetrical cells by co-pressing, co-firing at 1450 °C, and reduction in 10 % H2 – 90 % N2 at 800 °C. The resulting Ni/YSZ cermets are porous and adherent to the electrolyte, and its…
Abstract Flow‐induced coalescence in complex flow fields is studied using an in situ, real‐time small‐angle light scattering technique. Coalescence in a model polyisobutene–polydimethylsiloxane immiscible blend is triggered through step‐downs in the flow rate, creating a transition from a breakup‐controlled morphology…
The relaxed configurations of yttria-stabilised zirconia (YSZ) between 3 and 10 mol % of Y 2 O 3 were modeled using the pseudopotential technique. In the displacive limit of a double-well potential model, the vibrational mode corresponding to the soft phonon in pure c -ZrO 2 was calculated for each Y 2 O 3 composition…
Layered double hydroxides are antitype 2/1 clay minerals that can be synthesized rapidly under laboratory conditions. Due to their high anion exchange capacities, layered double hydroxides have been investigated as potential adsorbents for removal of anionic contaminants from aqueous systems. In this study, uncalcined…
A high temperature solid oxide fuel cell has been operated in low humidity (3 % H2O) methane using Y0.20Ti0.18Zr0.62O1.90 (YTZ) as the anode. The mechanism of methane electro-oxidation was investigated using ac and dc techniques at different anodic overpotentials and methane concentrations in the temperature range 788…
Abstract Alignment behavior of a discotic liquid crystalline triphenylene (C8OBT) on substrates coated with self-assembled monolayers (SAMs) of alkanethiol and asymmetrical disulfide was investigated by polarized microscopy. Discotic nematic (ND) and rectangular columnar (Colr) phases of C8OBT shows a different alignm…
ZnS 0.05 Se 0.95 nanocrystalline films were deposited onto fused silica and GaAs (100) substrates by the magnetron sputtering technique. The electrical conductivities of the films deposited onto fused silica substrates were measured in the temperature range of 180–300 K. It was observed that the low temperature conduc…
Die Dämpfung mechanischer Schwingungen in Festkörpern ist eine Auswirkung der inneren Reibung. Die Ermittlung der Dämpfungseigenschaften von Werkstoffen ist nicht nur für technische Anwendungen wichtig, sondern stellt eine zerstörungsfreie Analysemethode dar, die Rückschlüsse auf die Mikrostruktur zulässt. Es wird ein…
Semi-rigid polyesters having nitro- or methoxyazobenzene unit in the side chain and calamitic mesogen (biphenyl or 2,5-diphenyl-1,3,4-thiadiazole unit) in the main chain were prepared by melt polycondensation of diethyl isophthalates composed of the azobenzene units with three dioxydiundecanol derivatives of the mesog…
Further to the previous part [Surf. Rev. Lett.8(3/4), 367 (2001)], this part deals with VLEED numerical quantification of the Cu 3 O 2 bond-forming kinetics on the Cu(001) surface. Besides the solution-number certainty that has been ensured, the modeling exercises have enabled the full capacity of VLEED to be explored…
A pure macroscopic two-dimensional numerical model has been developed, capable of capturing the effects of dendritic arm coarsening on the transport phenomena occurring during a binary alloy solidification process. The general continuum conservation equations are aptly modified to take into account shrinkage induced f…