Materials Literature
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This chapter discusses structural crystallography and phase transitions. If all atoms in a crystal were exactly at their official lattice sites and there were no order-disorder ambiguity as to the position of these sites, then all the measurable physical quantities associated with the crystal would be exactly periodic…
The surface properties of materials are often the important determinants of their usefulness, and many of the chemical treatments now in use are aimed at modifying these properties. The important properties of polymer materials such as adhesion, friction, wetting, penetrability and biological compatibility are strongl…
Synthetic diamond radiation detectors made of ultrahigh-purity type IIa diamond crystals were developed. The diamond crystals, which were grown by high-pressure and high-temperature synthesis, contained less nitrogen impurity than 0.1 ppm, i.e., 1/10 of conventional type IIa diamond crystals. Since the ultrahigh-purit…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTPhotoinduced 1,3-Proton Shift in Methyldithiepines as a Potential Way of Modulating HyperpolarizabilitiesYongqin Wan, Alexei Kurchan, and Andrei KutateladzeView Author Information Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208 %[email pro…
The thermal stability of amorphous carbon ( a -C and a -C:H) has been studied by ellipsometry and spectrophotometry in the visible and near-UV range (1.5–5.6 eV). The dielectric function of amorphous carbon has been derived and analyzed using the Kramers-Kronig technique. The conventional analytical approach is shown…
In this work we report preliminary results on the properties of a non-polar bicyclohexane nematic liquid crystal. Moreover, its binary mixtures both with a low viscosity phenylcyclohexane and with a normal polar nematic liquid have been investigated. The elastic, viscous and electro-optical properties of these compoun…
Single-crystal-to-single-crystal reactions of a series of bifunctional styrylyl]pyrylium salts have been investigated using long wavelength irradiation conditions. The dimerization of the reactive olefins in the solid state was followed by X-ray crystallography. The results demonstrate that a homogeneous photoreaction…
A recently developed technique which allows a study of the localization of plastic flow during high-speed torsion testing is briefly described. High-speed photographs showing successive stages in the deformation of three rolled homogeneous armour (RHA) steel specimens are presented. Three stages are identified corresp…
The suspension polymerization of styrene in water with hydroxyapatite and calcium carbonate as Pickering emulsifiers and sodium dodecylbenzenesulfonate (NaDDBS) and poly(vinylpyrrolidone) (PVP) as surfactants was investigated. The adsorption of NaDDBS and PVP at the surface of the solids, the surface tensions of the a…
Trisulfide molybdenum complexes have been employed to produce nanotubes by simple heating in a stream of hydrogen. Bamboo-like stacking (see Figure) was observed, suggesting that the stimulus for the growth of MoS2 nanotubes is similar to that of their carbon equivalents. The wide experience gained with trisulfide com…
Abstract A two‐color laser photometric measurement system was used to follow birefringence changes in annealing of prestretched PET films. This technique was shown to be capable of detecting large retardation (and thus birefringence) changes beyond one wavelength of the light. The use of green and red lasers in the ph…
An enzyme from Comomonas acidovorans has been isolated that is specific for the stereospecific hydrolysis of (+)gamma-lactam. This so-called (+)gamma-lactamase has important applications in biotransformation reactions. The enzyme has been crystallized by vapour-phase diffusion using polyethylene glycol 4000 as a preci…
Alternating current thin film electroluminescent devices have been fabricated using sputter-deposited ZnS:Mn with and without codoped potassium chloride via both in situ and ex situ methods. In situ codoping proved to be difficult due to a memory effect in the deposition chamber. Samples codoped with potassium chlorid…
The nicotinium dichromate (NDC) oxidation of methyl phenyl sulfide (MeSPh) in acetonitrile, brought about by p-toluenesulfonic acid (TsOH), is first order in NDC and TsOH, and is zero order with respect to MeSPh in the concentration range investigated.The NDC oxidation of 14 para-, meta-and ortho-substituted phenyl me…
Dielectric spectroscopy and dc conductivity have been studied in KTiOPO4 and isomorphic crystals in a temperature range 150–400 K. The experimental data indicate two temperature regions related to different types of relaxation processes. Alternation of the activation energy, suppression of the dielectric dispersion, a…
The peptidoglycan-associated lipoprotein (Pal) from Escherichia coli is part of the Tol--Pal multiprotein complex used by group A colicins to penetrate and kill cells. Pal homologues are found in many Gram-negative bacteria and the Tol--Pal system is thought to play a role in bacterial envelope integrity. The Pal prot…
Swedenborgite, (Na 0.89 Ca 0.04 □ 0.07 ) Be 4 Sb O 7 , is hexagonal, unit-cell parameters a 5.4317(2), c 8.8571(4) A, V 226.31(2) A 3 , space group P 6 3 mc , Z = 2. The crystal structure was refined to an R index of 1.2% based on 290 unique observed reflections [| F o | > 5σ| F |] collected with a single-crystal diff…
To high purity 8 mol% Y2O3 doped ZrO2, 0–0.6 mol% Al2O3 were added. The microstructures were characterized by SEM, and the electrical properties were measured by impedance spectroscopy. The bulk resistivity increases with increasing Al2O3 content, the grain boundary resistivity and the grain boundary thickness also in…
A new norditerpenyl ester, named Calotropterpenyl ester, and two unknown pentacyclic triterpenoids, namely calotropursenyl acetate and calotropfriedelenyl acetate have been isolated from the root bark of Calotropis procera. Their structures have been established as 6,10,14-trimethylpentadec-6-enyl-2',4',8',12',16'-pen…
A New Monte Carlo code (EBUF) is developed to calculate improved point isotropic photon exposure buildup factors in media. Variance reduction techniques are used to perform calculations up to 60 mean free paths. EBUF accounts for coherent scattering and bound-electron Compton scattering. Bremsstrahlung photons and ann…