Materials Literature
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Detailed information on the preparation and application of antiozonants to the production of rubber has been collected from the patents published till 1987 inclusive. From among the numerous organic compounds acting as antiozonants and antioxidants, several classes can be distinguished and grouped on the gasis of the…
Abstract X-Ray powder diffraction data and unit cell parameters of industrially produced, as well as bench scale prepared, ammonium paratungstate tetrahydrate are reported and compared with current Powder Data File (PDF) (1989) patterns. A least-squares refinement resulted in two slightly different unit cells. Both ce…
On the basis of broad experimental material, the authors made the following conclusions: inert fillers influence the combustion of polymeric materials strongly only at high weight content; the fillers, that decompose into volatile products as CO2 and H2O can more strongly influence the combustion of composite compound…
The dielectric properties of the nematic liquid crystal, 4-4′-n-pentylcyanobiphenyl (K15), and three binary mixtures of K15 with 4-[4′-alkylcyclohexyl]cyanophenyl homologs have been studied. The parallel, perpendicular and isotropic dielectric constants are given as a function of temperature. All measurements were mad…
Crystals of the calcium-containing lysozyme from horse milk have been grown by precipitation with sodium phosphate. The crystals are orthorhombic space group P2(1)2(1)2(1) with cell dimensions a = 53.2, b = 57.1, and c = 38.2 A and contain a single molecule in the asymmetric unit. The crystals are suitable for high re…
Different models for calculation of the temperature rise under an electron beam spot are reviewed. From a study of the cathodoluminescence (CL) shift as a function of temperature in CdS, a model for determining the temperature rise is proposed.
The effects of high external pressures on the micro-Raman spectra of potassium chromate, K 2 CrO 4 , and potassium tungstate, K 2 WO 4 , have been investigated for pressures approaching 45 kbar. There is no evidence for a pressure-induced phase transition in the chromate, but there is clearly such a transition at ∼13…
Abstract Polyetheretherketone‐polydimethylsiloxane (PEEK–PDMS) block copolymers were synthesized from the condensation of dimethylamino terminated PDMS and hydroxy terminated PEEK oligomers in 1‐chloronapthalene. Yields for block copolymers synthesised from low molecular weight PDMS oligomers were good but yields were…
The characteristics of excimer lasers and the nature of ablation and etching processes are described. The two kinds of laser ablation mechanisms, thermal and electronic, are discussed. Thermal processes all rely on an intense laser pulse to heat a surface very rapidly. Electronic mechanisms do not rely on heating. Two…
Some optical investigations including measurements of birefringence and angle between the extinction positions in different domains, have been performed on [N(CH3)4]2MnCl4, In addition the domain structure has been studied using an optical microscope. The observed anomalies in the birefringence measurements clearly co…
Abstract The effects of rubber content, particle size and interparticle spacing on the fracture behaviour of toughened polymers over a range of strain rates and temperatures are discussed with particular reference to high‐impact polystyrene and rubber‐toughened nylons. It is concluded that the limiting factor in deter…
The effect of local anesthesia containing epinephrine on the survival of split- and full-thickness skin grafts remains unclear. In this blinded study, Xylocaine with or without epinephrine was injected subdermally prior to harvesting of split-thickness and full-thickness skin grafts on the dorsum of rabbits. After pro…
We first briefly draw the reader’s attention to some of our papers recently published in other journals. Then, after some comments on the admittance and impedance operators, we introduce the Calderon projectors, and we show how the operator formalism can be used in grating problems. Finally, we present theoretical con…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLandau theory of symmetry-breaking transitions: a basis for clarification of diffraction studies of phase behaviorHugo F. FranzenCite this: Chem. Mater. 1990, 2, 5, 486–491Publication Date (Print):September 1, 1990Publication History Published online1 May 2002Published iniss…
Aspiration is a serious complication of oral contrast media (CM). The authors investigated the effects of iotrolan, iopamidol, and diatrizoate in rats' lungs. To quantify the lung damage induced by CM, pulmonary water and hemoglobin contents were determined. Arterial blood-gas exchange (pH, PCO2, and PO2) also was det…
Improvements of welding processes by plasma or laser require a good knowledge of the microscopic properties of the liquid associated to the melted area. The development of new high temperature NMR probes allows to reach such a goal. In the case of alumina bearing liquids, the analysis of the 27Al resonance line shows…
The effect of pH on phosphate sorption by soil samples from two coarse-textured pedons of typic Paleudults in the perhumid tropical zone of Nigeria was studied by equilibrating air-dried soil samples adjusted to pH 3.5–6.5 for 48 h with 10 ppm P and 60 ppm P solutions at two concentrations of CaCl2 and NaCl. Phosphate…
The phase transitions undergone by [N(CH3)4]2 MnCl4 crystals in the 10–300 K temperature range have been explored through the absorption and emission spectra as well as lifetime measurements. The present measurements confirm the existence of phase transitions at Tc3 = 268.7 K and Tc4 = 175.6 K and provide clear eviden…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA New Pentacyclic Triterpene from Abutilon pakistanicumZaheer Ahmed, Syed Najam-ul-Hussain Kazmi, and Abdul MalikCite this: J. Nat. Prod. 1990, 53, 5, 1342–1344Publication Date (Print):September 1, 1990Publication History Published online1 July 2004Published inissue 1 Septem…
Three new series of cyanoaryl 4-alkylthioxybenzoates have been synthesized and characterized. The 4-cyanophenyl series displays only transient mesomorphic properties while the 6-cyano-2-naphthyl and 4-cyanobiphenyl series exhibit the classical nematic and smectic A phases; a reentrant nematic phase is also found in th…