Materials Literature
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The effect of 0.2 wt-%C on the microstructure of beta titanium alloys Ti-15X(Fe, Cr, Mn, Mo, Ni, Co, Cu, and V) has been studied using scanning and transmission electron microscopy. It has been found that coarse eutectic TiCx tends to be formed in beta titanium alloys containing Fe, Cr, Mo, and Mn, and relatively fine…
Abstract The objective of this preliminary work was to explore the fracture resistance of polytetrafluoroethylene (PTFE) (DuPont tradename Teflon) as part of materials characterization work related to the development of “reactive” material projectiles. Little mechanical property data is available on this material sinc…
Glasses of the composition 40 PbO–(60 − x) Sb2O3−x As2O3 :0.4 Cr2O3 (with x ranging from 10 to 55 mol%) were prepared. A number of studies, i.e. differential scanning calorimetry, IR spectroscopy, optical absorption, magnetic susceptibility, ESR spectroscopy and dielectric properties (constant ε, loss tan δ, ac conduc…
Benzocarbaporphyrins 4 were found to undergo regioselective oxidations with ferric chloride in methanol, ethanol, isopropyl alcohol, or ethylene glycol to give bridged benzo[18]annulene ketal derivatives 5 in excellent yields. These polar derivatives were generally isolated in a monoprotonated form and the correspondi…
Continuously variable ferroelectric (BST on sapphire) phase shifters based on all-pass networks are presented. An all-pass network phase shifter consists of only lumped LC elements, and thus the total size of the phase shifter is kept to less than 2.2 mm /spl times/ 2.6 mm at 2.4 GHz. The tunability (C/sub max//C/sub…
The strengths of metallic multilayers, composed of alternating layers of soft metals such as Cu and Nb, approach the theoretical limit of material strength when the bilayer periods are on the order of a few nanometers. We have investigated the damage mechanisms in these ultra-high strength nanolayered composite materi…
In NiMnGa alloy the crystal structure of low temperature phase is strongly related to transformation temperature. In the present study three NiMnGa alloys with different transformation temperatures were studied. Alloy A has the martensitic start temperature (M s ) near ambient temperature and M s of Alloy B is near Cu…
Efficient computational methods for the elastic field, self force and interaction forces of three-dimensional (3D) dislocations in anisotropic elastic crystals are developed for 3D dislocation dynamics (DD). The elastic field of a general dislocation loop is determined by incorporating numerically evaluated derivative…
Regenerated cellulose fibres have had an important role to play in the man-made fibre field. The very special characteristics of different types of regenerated cellulose fibres, e.g. mechanical properties, sorption characteristics, and aesthetics were conditioned by the differences in their fine structure due to fibre…
This paper describes a series of experimental studies to evaluate the performance of newly developed sensors for monitoring broadband acoustic emissions generated by acoustic cavitation. The prototype sensors are fabricated in the form of hollow, open-ended cylinders, whose inner surface is made from a thin film of pi…
We report here for the first time a new and improved approach to the complete synthesis and characterization of the unsymmetrical metallo- and metal-free phthalocyanine/porphyrazine (Pz/Pc) hybrids bearing peripheral nitro or amine functionality, H 2 [ Pz (n- Pr ) 6 ( BzNO 2 )] or H 2 [ Pz (n- Pr ) 4 ( BzNO 2 ) 2 ], w…
Abstract The effects of chitin/chitosan and their oligomers/monomers on the migrations of mouse peritoneal macrophage (PEM) and the rat macrophage cell line (rMp) were evaluated in vitro. In direct migratory assay using the blind well chamber method, the migratory activity of PEM was enhanced significantly by chitin a…
Abstract It is widely accepted that for the very smallest grain sizes (typically below 20–30 nm), dislocations play no significant role in the deformation of nanocrystalline materials. However, the grain-boundary mechanisms responsible for the reported decrease in strength with decreasing grain size in this regime (th…
The metamaterial considered is a planar wire-grid network loaded with closely spaced, orthogonal capacitors and inductors, positioned over a ground plane and parallel to it. Excited by a single-frequency point source, this metamaterial exhibits conical high-field regions called "resonance cones" which extend outward f…
A series of 6-O-(p-substituted phenyl)-modified beta-cyclodextrin derivatives, i.e., 6-O-(4-bromophenyl)-beta-CD (1), 6-O-(4-nitrophenyl)-beta-CD (2), 6-O-(4-formylphenyl)-beta-CD (3), 6-phenylselenyl-6-deoxy-beta-CD (4), and 6-O-(4-hydroxybenzoyl)-beta-CD (5), were synthesized, and their inclusion complexation behavi…
Ever since the discovery of ZSM-5 in the sixties, the templated synthesis of microporous materials has been a booming research field. More than one hundred structure types of microporous zeolites and aluminium phosphates have been synthesized and described. The templates are organic molecules with a carefully designed…
Bio-artificial tissues are being developed as replacements for damaged biologic tissues. Their mechanical properties are critical for load bearing applications. Current testing protocols for bio-artificial tissues vary widely and often do not consider viscoelasticity. Uniaxial stretch tests were performed on fibroblas…
Molecular dynamics simulations were used to study the structure of calcium silicate intergranular films (IGFs) formed between the basal planes of silicon nitride crystals. A multibody potential was used to describe the interactions between ions. Samples with different film thickness and CaO contents were studied. Epit…
Defect structure and migration pathways of cations in cubic zirconia (ZrO2) have been calculated using two computer modelling techniques. The first is based on the Mott–Littleton method, which considers defects to be embedded in an otherwise perfect crystal, and the second is the supercell approach, which allows finit…
Rhodium-complexed dendrimers supported on a resin were evaluated as catalysts for the hydroformylation of aryl olefins and vinyl esters. The results showed the reactions proceeded very efficiently at room temperature with excellent yields. Outstanding selectivity for the branched aldehydes was also observed in all cas…