Materials Literature
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Abstract An investigation of the Urbach rule in crystalline SiO 2 (α‐quartz), crystalline SiO 2 Ge, and vitreous SiO 2 in the framework of the models of Dow and Redfield and of Toyozawa shows that the fundamental optical absorption edge of SiO 2 is determined by strong exciton–phonon interactions. In the crystalline…
Summary Soil from a field under long‐term grass was treated with 0.02 m sodium periodate for various periods up to 1176 h, followed by 0.1 d sodium tetraborate for 6 h. This destroyed an increasing proportion of microaggregates >45 μm and carbohydrate. After periodate treatment for 6 h about 70% of the soil sugars…
Abstract Poly(4‐hydroxybenzoate) was prepared under a variety of reaction conditions. In addition to using the well‐known monomers 4‐acetoxybenzoic acid and phenyl 4‐hydroxybenzoate, p ‐tolyl 4‐hydroxybenzoate, 4‐pivaloyloxybenzoic acid, and 4‐trimethylsiloxybenzoyl chloride were also condensed. A new routine method f…
(Rp)- and (Sp)-5'-O-thymidyl 3'-O-thymidyl [18O]phosphates have been synthesized by reaction of the respective (Sp)- and (Rp)-phosphorothioate precursors with N-bromosuccinimide in dioxane and H218O. Stereochemical analysis of the product derived from the (Rp)-phosphorothioate by digestion with snake venom phosphodies…
Abstract Blends of poly(butylene terephthalate) (PBT) and a copolyester of bisphenol‐A with 50% terephthalate‐50% isophthalate (PAr), before and after transesterification, have been studied by thermal and dynamic mechanical tests to determine crystallinity and phase behavior. Blends without transesterification, as pre…
Abstract Gortdrumite superficially resembles chalcocite but is more distinctly anisotropic, and is present in a vein containing ferroan dolomite and baryte which cuts dolomitized limestones from the Gortdrum Orebody of County Tipperary, Ireland. It has an empirical formula of approximately (Cu,Fe) 6 Hg 2 S 5 . A disti…
Axenic cultures of diatoms are diluted with sterile medium so that drops containing only a single cell can be placed on sterile cover-slips. After a rapid microscopic check, the cover-slips are then placed in new culture medium. The whole process can be carried out aseptically with no difficulty.
The thermal decomposition and the glass transition temperature of poly(ethyl methacrylate) (PEMA) and poly(n-butyl methacrylate) (PnBuMA) were studied with a differential scanning calorimeter (DSC). The undecomposed and decomposed polymers were analyzed by gel permeation chromatography (GPC) for molecular weight distr…
(1983). Bonshtedtite, Na3Fe(PO4)(CO3) — a new mineral. International Geology Review: Vol. 25, No. 3, pp. 368-372.
The physicochemical aspects of the order–disorder phase transitions occurring in the Na 2 SO 4 –K 2 SO 4 system were investigated by thermal analyses, infrared absorption, and X-ray diffraction methods.Kinetic and structural studies on the compounds KNaSO 4 and K 3 Na(SO 4 ) 2 are reported in more detail.
ABSTRACT A simple method of determining the refractive index of the dispersed phase was applied on different gum‐stabilized oil‐in‐water emulsions, in which this refractive index is taken to be equal to that of the continuous phase at (extrapolated) zero optical density point. Refractive indices of dispersed phases we…
Neutral Red has been shown to undergo electrochemical and photoelectrochemical reactions in aqueous solution. At a pH above the pK,, the dye was oxidized with the loss of one proton with each electron. Similarly the protonated dye was oxidized at pH values below the pK,. Over the pH range examined, 1.0-9.2, Neutral Re…
Data are presented for the thermal diffusivity/conductivity of hot‐pressed mixtures of SiC and AlN. Results indicate that hot‐pressing at higher temperatures, which permits solid‐solution formation, results in significantly lower thermal diffusivity/conductivity than is obtained by hot‐pressing at lower temperatures,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPlasticizer migration from plasticized poly(vinyl chloride) into liquids. Effect of several parameters on the transferDjelloul Messadi, Jean Louis Taverdet, and Jean Maurice VergnaudCite this: Ind. Eng. Chem. Prod. Res. Dev. 1983, 22, 1, 142–146Publication Date (Print):March…
ABSTRACT The role of microtubules in silicon metabolism leading to valve formation was investigated in the pennate diatom Navicula saprophila Lange‐Bertalot & Bonik. By using synchronized cells blocked after mitosis and cytokinesis but prior to cell wall formation, effects due to inhibition of mitosis were elimina…
A diffusion model was developed to analyze the rate at which Fe 2+ /Fe 3+ equilibration occurs in a Ca‐Al‐borosilicate melt in an air atmosphere at 1260°C. The resulting diffusion coefficient of oxygen determined from the model of 3.7 × 10 −7 cm 2 /s is in agreement with the range of values reported for other glass‐me…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExchange coupling in triplet ground state dimeric molecules with specific reference to bis(.mu.-pyridine N-oxide)bis[bis(nitrato)(pyridine N-oxide)copper(II)] and bis(diethyldithiocarbamato)copper(II)William E. HatfieldCite this: Inorg. Chem. 1983, 22, 5, 833–837Publication…
Abstract The Boom Clay is an important raw material for the Belgian structural clay products industry. It can be divided into several lithological sub-units. In order to obtain an insight in the parameters which characterize these different units, and which affect the overall properties of the clay, a detailed chemica…
We have studied Williams Domain (WD) patterns in detail by observing tomograms with a polarizing optical microscope, confirming the following characteristic features: (1) there are two types of real images, upper and lower; (2) the spacings between the neighboring imaginary image lines are not uniform; and (3) when th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of polymer chain tacticity on the fluorescence of molecular rotorsRafik O. Loutfy and David M. TeegardenCite this: Macromolecules 1983, 16, 3, 452–456Publication Date (Print):March 1, 1983Publication History Published online1 May 2002Published inissue 1 March 1983http…