Materials Literature
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The influence of precracking techniques in the crack growth behavior of yttria‐stabilized tetragonal zirconia polycrystals (Y‐TZP) is investigated. Load‐bridge and cyclic‐compression precracking enhance subsequent tensile crack growth rates, in comparison to results that are found with precracks that are extended unde…
Abstract Nanocrystalline ZrO 2 ‐ and Y 2 O 3 ‐powders with grain sizes from 5‐20 nm were prepared by the Inert Gas Condensation method. The powders were mixed in different fractions, pressed into green bodies and sintered to ceramic samples with 35‐49 nm average grain size. The phase, grain size and specific surface a…
The cryptand L can accommodate a Co(II) ion inside the cavity at the tren end, forming a CoN4 complex. The Co(II) ion further accepts a SCN- anion, forming a distorted trigonal bipyramidal complex. The Co(II) cryptate can act as an efficient catalyst for oxygenation of organic substrates using molecular oxygen and 2-m…
A detailed study of the electrical and magnetic properties of polycrystalline ${\mathrm{La}}_{0.52}{\mathrm{Gd}}_{0.15}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ has been carried out. This perovskite-type compound should be a canted ferromagnetic metal at low temperatures. The magnetization and conductivity show consider…
Attachment of four oligomeric (MW 550) ethylene glycol chains to tetraphenylporphyrin results in a highly viscous, room temperature melt a hybrid redox polyether that is highly concentrated in porphyrin sites (∼0.4 M) and will dissolve LiClO 4 electrolyte. Microelectrode voltammetry in undiluted, free base and Co and…
We present the results of a parallel study of the atomic structure of the ∑ = 5, (210), θ = 53·13° and (310), θ = 36·87°, [001] tilt axis grain boundaries in bcc Mo, by computer simulation and high-resolution electron microscopy (HREM). Excess energy values of different boundary configurations are obtained via a quasi…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorShear-Induced Single Crystalline Mesophases in Physical Networks of Gel-Forming Triblock Copolymer SolutionsR. Kleppinger, N. Mischenko, E. Theunissen, H. L. Reynaers, M. H. J. Koch, K. Almdal, and K. MortensenView Author Information La…
All articles of this category The palladium-catalyzed reaction of the ethyl 2-acetyl-4-pentynoate tosylhydrazone with aryl iodides in the presence of K 2 CO 3 and catalytic amounts of a palladium complex affords 1,2,3,5-substituted pyrroles in satisfactory yield. palladium catalysis - tosylhydrazones - annulation - py…
Electron induced gas desorption yields from stainless steel, copper, and aluminum surfaces have been measured for electrons of 300 eV energy. The main gases desorbed were H2, CH4, H2O, CO, and CO2. The effect of increasing the temperature on the gas desorption yields was measured and the only yields affected were thos…
Abstract Binary copolyesters were prepared by polycondensation of the trimethylsilylester of acetylated β‐(4‐hydroxyphenyl)propionic acid (HPPA) with acetylated 4‐hydroxybenzoic acid (HBA), vanillic acid (VA), 6‐hydroxy‐2‐naphthoic acid (HNA), 4‐hydroxycinnamic acid (HCA) or 4′‐hydroxybiphenyl‐4‐carboxylic acid (HBCA)…
Microstructures of block copolymers in the strong segregation limit are characterized by well-defined interfaces separating the different block materials into domains on a nanometer scale. In this paper, we address the effects of architectural and conformational asymmetry of the blocks on the interfacial curvature cha…
The new algorithm of the thermal conductivity and thermal diffusivity determination from the transient hot-wire method has been applied to measurements performed in several solid materials. The algorithm makes use of the exact formula for the temperature variations, instead of its simple, asymptotic form that has been…
Monodispersed nanospheres of carbon are obtained by the pyrolysis of methane or benzene at high temperatures in the presence of hydrogen without the use of any catalyst. Carbonization of these hydrocarbons over transition metal powders (for example Ni) or supported metal catalysts, however, yields carbon nanotubes.
Dielectric relaxation phenomena are studied in detail at the 107 K structural phase transition in ${\mathrm{SrTiO}}_{3}.$ These loss phenomena are explained in terms of the dynamics of domain walls that occur at the cubic-to-tetragonal phase transition and exist as precursor phenomena (locally ordered regions) in the…
Abstract— Octaphenyltetraanthraporphyrazinato palladium undergoes a self‐sensitized photoreaction in the presence of oxygen to form a substituted palladium phthalocyanine with four endoperoxide bridges. This compound exhibits photophysical behavior similiar to palladium tetra‐tert‐ butyl‐phthalocyanine. The phthalocya…
We report an experimental procedure to optimize the current profile of a focused ion beam probe, with a special emphasis on high resolution applications. The optimized operating conditions are given for three specific cases: specimen thinning for electron microscopy, nanoetching, and nanolithography. We present high q…
Inexpensive and efficient cellulose-based adsorbents were prepared by the reaction of cross-linked polyethylenimine (CPEI) with an agricultural waste (i.e., wood sawdust). Factors affecting the extent of amination, such a CPEI concentration, pH, time, and temperature of reaction as well as sawdust particle size range,…
Abstract Transport models of diffusion‐induced bubble growth and collapse in viscous liquids are developed and evaluated. A rigorous model for these important phenomena is formulated taking into account convective and diffusive mass transport, surface tension, and viscous and inertial effects. Predictions for bubble g…
Propagation of elastic waves near the cohesive limit of a solid is of interest in understanding the speed at which strain energy is transported in front of a mode-I crack tip. It can be argued that the crack propagation velocity is limited by how fast the strain energy can be transported ahead of the crack tip to sust…
X-ray crystal structures of three substituted 4,4‘-biphenyldiamines, namely, 2,2‘,6,6‘-tetramethylbenzidine (TMBZ), 2,2‘-dimethylbenzidine (DMBZ) and 2,2‘-bis(trifluoromethyl)benzidine (BFBZ), were determined. The torsional angles between the two phenyl rings for TMBZ, DMBZ, and BFBZ are φ = 83°, 75°, and 59°, respect…