Materials Literature
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A homologous series of cholesteryl (trans-p-n-alkoxy) einnamates has been prepard by reacting trans-p-n-alkoxy cinnamoyl chlorides with cholesterol, and its mesomorphic behaviour studied. All the members of the series are enantiotropic mesomorphic. The lower members of the series exhibit cholesteric mesophases, wherea…
Th e in fra red spec tra of matri x iso la ted BaO, have bee n o bse rv ed and ass igne d. Ba ato ms were a ll owe d to react with a n a rgo n oxyge n mixture a nd co nd e nsed o n a li qu id hydroge n cuo led s urface .
Bis-2,5-(2-benzazolyl)hydroquinones, a new class of luminescent benzazoles, possess unusally long wavelength luminescence between 630 and 730 nm.
The chemical structure of glycoside G (I), C36H56O13, mp 232-233°, [α]19D+30.2°(EtOH) and glycoside K (V), C40H66O16, mp 240-241°, [α]20D -27.58°(MeOH) were isolated from Bei-Wujiapi (cortex of Periploca sepium BGE.) and established to be periplocin and Δ5-pregnene-3β, 20α-diol(20)-β-D-glucopyranosyl (1glu→6glu)-β-D-g…
The possible interaction has been studied between plastics and several drugs and pharmaceutical adjuvants such as parabens, quaternary ammonium salts, and HCO-50 (polyoxyethylene derivative of hydrogenated castor oil). It was found that hydrophobic interaction plays a major role in adsorption of parabens to several pl…
IO2–4(ε360ca. 1000 M–1 cm–1) ions and IO4˙ε520ca. 3000 M–1 cm–1) radicals are formed by pulse radiolysis of periodate ion in aqueous solution.
The Born model of the ionic crystal is used to calculate the energies of formation of point defects in CaF2 and UO2 in the zeroth, first and second orders. The results of calculation, to all orders, indicate that anion-Frenkel pairs are the intrinsic defects in CaF2 and are in agreement with previous calculations. In…
The changes in the electrical resistivity of nickel-rich Ni-Nb alloys due to the formation of short-range order exhibit an anomalous dependence on the solute concentration. This anomaly can be explained by the formation of embryos of long-range order of the type Ni8Nb in alloys approaching the NisNb composition and ne…
Abstract Der Einfluß der Elektronenreemission auf die Anlaufkennlinie wird berechnet und mit Messungen an den Primärelektronen in einer Niederdruckentladung verglichen. Die Messungen zeigen die von der Rechnung vorhergesagten Strukturen, die auf der Energieabhängigkeit des Reemissionskoeffizienten beruhen. Aus der Mat…
The kinetically controlled alkylation of palladium corrole ambident anions occurs both at the nitrogen atom (N-21) of ring A and at a peripheral carbon atom (C-3). Variation in solvent, from dipolar aprotic to strongly hydrogenbonding, allowed some control of the C:N alkylation product ratio. The palladium 2,3,7,8,12,…
Several mono and bistrithiocarbonates were synthesized by the reaction of the correspondingmono and bisepoxides with carbon disulfide in the presence of potassiumhydroxide. These trithiocarbonates were successfully obtained even in the presenceof a catalytic amount of potassium hydroxide. Potassium methoxide instead o…
Les spectres de diffusion Raman de monocristaux orientés sont étudiés dans les deux phases. Outre le mode ferroélectrique étudié en premier par Kaminov et Damen [1], on observe dans la phase ferroélectrique une raie fine de diffusion à 515 cm-1 liée au déplacement de l'atome de phosphore. L'étude est complétée par cel…
The effects of xenon-arc radiation, using an Atlas Weather-Ometer and a clear glass pyrex filter system, on the breaking strength, extension-to-break, and the energy-to-break for several nylon, polyester, and polyester/cotton yarns were compared to these of outdoor exposure behind window glass. Both types of exposure…
Strontium sulfate in equilibrium with aqueous solution leaches selectively from barium-strontium sulfate solid solutions at 25 degrees centigrade and at 1 atmosphere. Equilibrium concentrations of Sr ++ and Ba ++ in aqueous solution are not significantly different from values calulated on the assumption that the chemi…
Cleavage and growth faces of ammonium perchlorate have been examined by high-power interference–contrast microscopy. From the observed directions of etch-pit arrays on three crystallographically distinct faces of the orthorhombic form of ammonium perchlorate, and also from the nature of the slip bands on deliberately…
Nous avons commencé dans les précédents numéros des Annales de Physique (Tome 6, n° 4 et 5, pages 189 à 326), la publication d’une monographie consacrée à l’étude des propriétés physiques d’un système atomique en interaction avec un champ de radiofréquence.
An analysis is presented of the forced oscillations of a gas-filled bubble at rest in a large body of a linear viscoelastic fluid. Two types of forcing are considered. In the first, oscillations are induced by a pressure surge on the system. For the three-parameter fluid model employed, numerical computations show tha…
Abstract ESR measurements of Cr 3+ ions in SrTiO 3 at orthorhombic lattice sites in the cubic phase of the crystal are described. The orthorhombic distortion is caused by an oxygen vacancy in the neighbourhood of the Cr 3+ ion. A model of the displacement of the neighbouring oxygen ions is proposed. The values of the…
Abstract A field study was conducted to determine extractable phosphorus variability on highly fertilized calcareous soils when three different ratios (1:10, 1:50, and 1:100) of soil to Bray no. 1 extracting solution were used. Calcium carbonate equivalence (CCE) was determined on all samples and calcite/dolomite frac…
Comments are made on a recent paper by Hofman and Breitling on the rate of electromigration in thin films. It is shown that the simple concept of electron momentum transfer leads to a quadratic relation between the current density and rate of electromigration, in agreement with Black. Comments on the difficulty of rel…