Materials Literature
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The Ar ion beam etching (IBE) of InP has been studied in orded to clarify its applicability as a microfabrication technique for devices with submicron geometry such as integrated optics devices. The IBE rate has been determined as a function of ion energy, current density and angle of beam incidence. The crystalline q…
Continuum mechanics has been used to work out the structure and properties of disclinations in nematic and cholesteric liquid crystals. After a brief review of the earlier works on the energetics of disclinations in the one constant approximation, we consider the effect of elastic anisotropy. Elastic anisotropy not on…
Abstract The nature and stability of surface species of CuCl 2 supported on α‐Al 2 O 3 , γ‐Al 2 O 3 , and SiO 2 were investigated by using X‐ray diffraction techniques and reflectance spectroscopy. No specific chemical interaction of CuCl 2 is observed on an inert α‐Al 2 O 3 support, as opposed to hydrated carriers as…
Abstract ULTEM® polyetherimide resin is characterized by a combination of high performance mechanical, thermal, flammability, and electrical properties. The exceptional mechanical properties are typified by a 15,000 psi tensile strength and 480,000 psi flexural modulus. Because of its amorphous structure and outstandi…
Previous work has shown that native lysozyme (N) is completely denatured by the addition of guanidinium chloride (conformation D) but that partially denatured conformations appear in other denaturants. Conformation I appears when LiClO4 is added to the protein, and conformation II is caused by heating. We have now det…
Abstract Basische Aluminiumchloridlösungen wurden aus Lösungen des neutralen Salzes durch Zugabe von Lauge bzw. Auflösen von metallischem Aluminium hergestellt. Ihre Untersuchung mit der Ferronmethode und der 27 Al‐Kernresonanz ergab in den Lösungen beider Darstellungsarten monomere, tridekamere und polymere Aluminium…
Citrate synthase was purified to homogeneity from a Gram-positive bacterium (Bacillus megaterium) for the first time. The Mr of the native enzyme was determined to be 84 000 (S.E.M. +/- 5000). Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel filtration in guanidinium chloride revealed a single protei…
We examine two heat transfer and phase change problems having explicit solutions. The first involves melting of an initially cold material and clarifies the meaning of a recent result of Tarzia [5]. The second concerns a model of binary alloy solidification which, in some cases, is seen to be incorrect.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemical reduction of an isomeric pair when the products interconvertAlan M. Bond and Keith B. OldhamCite this: J. Phys. Chem. 1983, 87, 14, 2492–2502Publication Date (Print):July 1, 1983Publication History Published online1 May 2002Published inissue 1 July 1983https:…
Abstract The solvent influence on two‐ phase structures resulting from drying films of segmented polyetherurethanes of different hard segment contents and molecular weights was investigated by infrared dichroism measurements of the orientational behaviour of the hard segments. A low density of physical crosslinking an…
The effect of an external magnetic field on the orientational order of a nematic liquid crystal has been examined using both Landau-de Gennes and Maier-Saupe theories. In the Maier-Saupe approach a rotationally invariant form of the pseudo-potential is introduced, which in the absence of an external field leads to thr…
Abstract Excitation and emission spectra for CaS:Ce 3+ and CaSe:Ce 3+ phosphors are measured at 6, 80, and 300 K. The vibrational structure on the emission bands 2 T 2g → 2 F 5/2 , 2 F 7/2 and the excitation band 2 F 5/2 → 2 T 2g is analysed by the use of energy matrices in order to determine the coupling constant of…
The planarization properties or thickness changes on topographical features are examined in detail for several types of spun‐on polymer films. A profilometer is used to measure the step height changes of isolated line features of various dimensions. The viscosity of the solution appears to give a reasonable indication…
A new method, for solid‐state bonding between ceramics and metals was developed. An interlayer, which is a composite of the materials to be bonded, is used. The technique can be applied to materials which cannot be bonded by conventional diffusion‐bonding methods because of thermal‐expansion mismatches. It is ex pecke…
In this paper, the current state of the art of molecular theories of nematic mesophases is reviewed. For this purpose, the many theories of nematogens which have been proposed are grouped into two classes: (1) the Maier-Saupe theory and its extensions and variants, which assume that nematic long-range order is primari…
The chromatin structure in solution has been studied by the flow linear dichroism method (LD) in a wide range of ionic strengths. It is found that increasing the ionic strength from 0.25 mM Na2EDTA, pH 7.0 to 100 mM NaCl leads to a strong reduction of the LD amplitude of chromatin and inversion of the LD sign from neg…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSemiconductor electrodes. 50. Effect of mode of illumination and doping on photochemical behavior of phthalocyanine filmsPatrick Leempoel, Fu Ren F. Fan, and Allen J. BardCite this: J. Phys. Chem. 1983, 87, 15, 2948–2955Publication Date (Print):July 1, 1983Publication Histor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbon-13 line shape study of two-site exchange in solid dimethyl sulfoneMark S. Solum, Kurt W. Zilm, J. Michl, and David M. GrantCite this: J. Phys. Chem. 1983, 87, 15, 2940–2944Publication Date (Print):July 1, 1983Publication History Published online1 May 2002Published ini…
The synthesis and some important properties of the l-(trans-4′-n-alkylcyclohexyl)-2-(4”-cyanophenyl)ethanes—where n-alkyl = C 1 to C 7—are described. These stable low melting materials have excellent properties comparable in many ways with those of the PCH materials wherein the cyclohexyl and phenyl rings are directly…
Abstract Permeability and time‐lag measurements for H 2 and CO in poly(vinyl chloride) (PVC) plasticized with tricresyl phosphate show that the apparent diffusion coefficients at first decrease as the plas‐ticizer concentration is increased. The diffusion coefficients then increase as the additive concentration is rai…