Materials Literature
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The oxidation states of chromium dissolved in binary sodium silicate glasses were analyzed by X‐ray photoelectron spectroscopy (XPS). The measured “equilibrium” Cr 6+ fractions in glasses with varying Na 2 O contents are shown to be in good agreement with results obtained by other techniques reported in the literature…
Abstract Defect Sites of CdO, Reducibility, Analysis Three procedures of chemical analysis are proposed for the direct determination of excess Cd in CdO: a spectrophotometric, a titrimetric and a gravimetric one, for 0-1500 ppm, 500-50,000 ppm and above 5%, respectively. The good reproducibility and reliability is ill…
Solid mixtures containing initially uniform dilute concentrations of impurity elements may, upon the application of mechanical and thermal loading, develop regions of high impurity concentration that could result in local degradation of material properties. To address these degradation processes, a fully coupled therm…
A commercial corrosion measurement system has been used in conjunction with an AC superposition circuit to produce linear potentiodynamic anodic polarizations of AISI 303 and AISI 316 stainless steels (SSs) in 1 N H2SO4. The resulting plots show that AC has a depassivating effect on the normally passive region of the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and properties of iron(II), cobalt(III), and zinc(II) N-alkylporphyrin complexes involving five-membered metal-O-C:C-N-metallacyclesJean Paul Battioni, Isabelle Artaud, Daniel Dupre, Philippe Leduc, and Daniel MansuyCite this: Inorg. Chem. 1987, 26, 11, 1788–1796…
The mechanism of the so called "area effect" in vacuum dis charge studies was investigated. Point-plane aluminum electrodes were used with point radius 1.5 mm and gaps between 0.5 and 10 mm. It was found that a capacitor connected in parallel with an electrode gap reduces the electrical strength in a manner similar to…
Carbon-14 is produced in pressurised heavy water reactors (PHWR), mainly as an activation product in the fuel. It is also produced in the heavy water used as the primary coolant and moderator, and is produced in the air in the annular space between the pressure tube and calandria tubes as well as in the free space in…
A mathematical model is developed for the corrosion of a rotating iron disk in sulfuric acid. The model treats explicitly the coupling of interfacial reactions with the mass transfer of ionic species by migration, diffusion, and convection in both the diffuse part of the double layer and the diffusion layer. The corro…
Abstract Structural changes in poly( L ‐alanine)(PLA), a model compound related to tussah silk fibroin, induced by heat treatment have been studied by differential thermal analysis, x‐ray diffraction, and infrared spectroscopy. PLA heated below 300°C shows x‐ray patterns very similar to those of the α‐helix crystallin…
Coralloid speleothems are commonly distributed in Togawa-Sakaidani-do Cave in Miyazaki Prefecture, Central Kyushu, but their speleological study has not heretofore been achieved. Light and scanning microscopes analyses revealed that coralloid speleothems consist of alternating layers of diatom colonies, detrital miner…
SUMMARY A mica was inserted into the soil at four sites to try to identify, in situ , the physico‐chemical changes in the soil caused by the introduction of different tree species, and especially conifers. Changes in the chemistry and mineralogy of the mixed‐layered mica, mica‐chlorite, vermiculite, after 1 1 / 2 and…
The degradation behavior of various dielectric systems for power capacitor use is discussed. Accelerated life testing of prototype capacitors and their constituent dielectric materials are described in detail. The composite polypropy lene/kraft paper system was estimated to have a life time of more than 30 years in se…
Abstract The crystal structure of TTF·BTDA–TCNQ complex was determined by an X-ray diffraction method. The crystals are monoclinic, space group P21⁄n with a=9.660(1), b=7.231(1), c=14.628(2) Å, β=91.31(1)°, and Z=2. The structure was solved by the direct method and refined by the block-diagonal least-squares method to…
Synopsis The optical properties of human hair were studied by photogoniometry. Starting from an optical model of hair, we developed a computerized method of decomposition of the goniophotometric curve. From our analysis we obtained structural parameters of the hair surface, average scale angle and cosmetic parameters…
Abstract In the present work, fusion behavior, crystallinity, and mechanical properties of beverage bottle poly(ethylene terephthalate) (PET) was compared with those of the virgin material. Viscosimetry measurements, differential scanning calorimetric studies, impact and tensile determinations were made in both materi…
Abstract The electronic structures of 1,4-dihydropyrrolo[3,2-b]pyrrole and some of its alkyl derivatives were studied by means of He(I) photoelectron spectroscopy combined with the MNDO calculation and a first-order perturbation theoretical method. The first five bands of the parent pyrrolopyrrole are assigned, from t…
Abstract The kinetics of the direct synthesis reaction (Si + 2CH 3 Cl → (CH 3 ) 2 SiCl 2 ) were measured on a Cu 3 Si alloy containing 1.2 atom % Zn. Reaction was carried out in a differential reactor (520–595 K, 1 atm) attached to an ultrahigh vacuum (UHV) system. Auger spectroscopy was used to characterize the surfa…
The crystal structure of a REE-bearing vesuvianite from San Benito County, California, was determined using single-crystal X-ray diffraction methods. The sample with tetragonal space group P4/nhas cell parameters of a : 15J99(3) and c: ll.9l7(3) A. An R value of 6.640/o was reached for 287 4 unique reflections with I…
Abstract IR absorption spectra of the Mn 1− x Zn x Fe 2 O 4 ferrite‐spinel system are investigated in the frequency range ν = 800 to 40 cm −1 . The spectra of the second derivative d 2 T /dν 2 are obtained from the computer processed experimental transmission spectra ( T ). On their basis the two complex bands ν 1 and…
A new orange‐emitting phosphor, (Ca, Mg)S:Mn, was developed to replace a Cd compound, , which is potentially an environmental problem. With 1.5% Mg and 0.8% Mn, the emission color of (Ca, Mg)S:Mn is equal to the brightness of a 9 or 12 in. monochromatic tube and is 20% higher than that of . The addition of Mg as well…