Materials Literature
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The hydrolysis of tri-sec-butoxyaluminum in the presence of nonionic surfactants leads to mesoporous alumina molecular sieves with wormlike arrays of channels with uniform diameters in the range 2.4 – 4.7 nm, depending on the nature of the surfactant. Molecular sieves of this type are of interest as possible catalysts…
The transport properties of electrons and holes in poly(dialkoxy-p-phenylene vinylene) (PPV) are investigated by current–voltage measurements using Ca as an electron and indium-tin-oxide as a hole injecting contact. Both the electron and hole currents are dominated by the bulk conduction properties of the PPV, in cont…
Spun cast alloy HP50–Nb tubing retired from service in a steam reformer after approximately 8 years of service had stress rupture properties suggesting very short remaining life. Microstructural examination, however, indicated little or no creep damage (cavitation) but did reveal extensive microstructural modification…
An in situ method of monitoring the electron cyclotron resonance etching of III-V semiconductor heterostructures is discussed for in-plane lasers. Surface reflected and Fabry-Perot interference signals determine the etch depth, rate and surface quality. The etching accuracy is better than 500 /spl Aring/. The etch mon…
We have studied ion-beam-induced epitaxial crystallization and densification of sol-gel zirconia thin films on single-crystal yttria-stabilized zirconia (YSZ) substrates. The spin-coated sol-gel zirconia thin films (100 nm) on YSZ substrates were irradiated at 300 C with various ion beams (360 keV argon, 360 keV neon…
Abstract The spectral, polarization, and kinetic characteristics of luminescence are studied for In + and In 2+ ions associated with interstitials and vacancies in an X‐irradiated KCl: In crystal. It is shown that the 2.08 eV emission is caused by the electronic transitions from the tetragonal minima of the triplet re…
Abstract Molecules of the amphiphilic polyalcohol [9]‐10‐[9] arborol (molar mass M = 1053 g mol −1 ) dissolved in water form gels which are thermo‐reversible and shear sensitive. The gel formation sets in above a characteristic composition y gel of the solution and temperature T gel ( y gel = 7.5·10 −3 ; T gel ≈35°C;…
The results are presented of an investigation of radioluminescence and phosphorescence spectra, decay of phosphorescence at a constant temperature, and thermostimulated luminescence of transparent BeO:Li ceramics. The phosphorescence decay dependence on time suggests the appearance of tunnelling.
Abstract A linear relationship exists in oxide glasses between glass transition temperature (T g ) and quadrupole splitting (Δ) of Fe 3+ . DTA and Mössbauer measurements of silicate and tungstate glasses yielded large slopes of 680 and 260 °C/(mm s -1 ) from the slope of the straight lines when Fe 3+ occupied, as netw…
This paper deals with the spherically symmetric Stefan problem in three space dimensions. The melting temperature satisfies the Gibbs–Thomson law. The solution is obtained as a limit of solutions of similar problems containing a small additional kinetic term in the melting temperature. Under some structural assumption…
Elastomer–elastomer joints are a special case of polymer bonding. Interfacial adsorption, molecular interdiffusion, and entanglements, as well as chemical bonding, are the different mechanisms which intervene in adhesion phenomena. Their relative contribution is not well known and depends on many parameters. If the fo…
A noise analysis for a planned PIN diode X-ray detector array using CMOS technology explores the affect of allowed device dimensions on attainable energy resolution using a methodology which allows low frequency, process dependent 1/f and 1/f/sup 2/ terms to be explicitly evaluated for arbitrary noise filters. We find…
The authors intend the book to be an introduction to the field of radiation protection dosimetry. Having just been published last year, the book is able to take into account all the changes and developments that have come in recent ICRP and ICRU reports. The book is aimed at graduate students or as a reference work fo…
We report an experimental study on the pattern dynamics of the salt-crystal (NaCl) surface when dissolved from below by its own aqueous solutions with mass concentrations between 0.0% and 24.0%. The surface pattern roughness grew exponentially for a range of unstable wave numbers with a fastest growing wave number ${k…
We have made extensive studies of the charge-carrier mobilities in the discotic hexagonal mesophases of triphenylene-based discotic liquid crystals. Using the time-of-flight technique, transient photocurrents were measured yielding charge-carrier mobilities for various electric fields and temperatures. Starting from p…
Solid forms fixing nuclides were produced from Cs-mordenite and Sr-zeolite A by calcination at 1,200°C for 1 h. Cesium and strontium were uniformly dispersed in pollucite (CsAlSi2O6) and Sr-feldspar (SrAl2Si2O8), respectively. Compressive strength of the products increased with decreasing particle size of starting zeo…
The permeability variations of carbon dioxide, oxygen, and nitrogen through isotactic polypropylene, heterophasic ethylene-propylene (E-P) copolymers, and polyethylene films were measured during photo-oxidation using polychromatic light at 60°C in air. For polypropylenebased samples the permeability decreases with inc…
A thin film‐of zinc octakis (β‐octyloxyethyl) porphyrin (ZnOOEP) is capable of trapping and detrapping charge in an appropriate electric field under irradiation. An effective charge capacity of the order of 30 μC/cm 2 or 10 18 charges/cm 3 was obtained with sandwich structures of ITO/ZnOOEP/ITO (where ITO is indium ti…
The line-beam response function, needed for skyshine analyses based on the integral linebeam method, was evaluated with the MCNP Monte Carlo code for photon energies from 20 to 100 MeV and for source-to-detector distances out to 1000 m. These results are compared with pointkernel results, and the effects of bremsstrah…
A new “incipient‐wetness” method is proposed for the synthesis of chemically stabilized β‐cristobalite (CSC) that avoids the need to handle liquid phases as required by the sol‐gel routes proposed in the literature. Stoichiometric compounds with the composition Si 1–x Al * x Ca 1/2 O 2 have been investigated. ×= 0.07…