Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInhibition of calcium fluoride crystal growth by polyelectrolytesZahid AmjadCite this: Langmuir 1991, 7, 10, 2405–2408Publication Date (Print):October 1, 1991Publication History Published online1 May 2002Published inissue 1 October 1991https://pubs.acs.org/doi/10.1021/la0005…
The magnetization curling mode for an infinite cylinder with a uniaxial magnetocrystalline anisotropy is considered. The angular dependence of the nucleation field HN and the coercive force Hc are estimated as a function of the radius, the magnetocrystalline anisotropy, and the inclination of the axis to the applied f…
Deletion of the structural gene for phosphoglucose isomerase (pgi) of Escherichia coli dramatically alters the path of glucose catabolism by diverting carbon into the hexose monophosphate shunt. The effect of this genetic alteration on the conversion of glucose to tryptophan by strains optimized for the biosynthesis o…
Abstract Auger electron spectroscopy (AES) and factor analysis (FA) were applied to study the chemical structure of oxidized brass layers and rubber‐to‐brass interface of tyre cords. The optimum requirements of sample preparation, instrument performance, data acquisition and analysis were determined to ensure accurate…
Aqueous colloidal suspensions in the two systems of CVD‐processed ultrafine mullite powder (<0.1 μm), ‐Si 3 N 4 whisker and ‐mullite whisker, were prepared near the isoelectric point of mullite (pH 7.0) to prevent cracking during drying of wet green compacts consolidated by filtration. The freeze‐dried porous green…
Abstract Transmission electron microscopy (TEM), including selected area electron diffraction (SAED), has been used to identify polytypes in illite, phengite and muscovite from samples representing a wide range of diagenesis and low-temperature metamorphism. Samples include Gulf Coast sediments, sediments from the Sal…
The surface of the polyamidoamine (PAMAM) starburst dendrimers of Tomalia et al. is indeed fractal. Two independent analyses yielded as fractal dimension D 2.41 ± 0.04 and 2.42 ± 0.07. The fractal dimension of several enzymes lie in this region, so the starburst dendrimers will probably mimic biomolecules.
X-ray structure analysis demonstrates that alternating AB type chains of general composition (cat)2[MnIII(sal)2(CH3OH) 2]-[MnIII(sal)2] [cat = Na+ (1), K+ (2), NH4 + (3); sal = salicylate] can be prepared by the reaction of MnCl2 with salicylic acid and the appropriate base. The molecular structures are composed of th…
A series of the absorption spectrum changes in polypyrrole films were analyzed using the Nernst equation by two models. One is the "monomer unit model" and the other is the "polaron/bipolaron model." In the first model, formal electrode potentials and the n‐values were obtained and used to fit calculated ΔAbs vs. E cu…
Amorphous polymer films containing hyperpolarizable dye molecules are poled by an electric field applied parallel to the plane of the thin film. The resultant second harmonic generation is much stronger than predicted by the standard model of dipolar interactions, and furthermore indicates asymmetry both parallel and…
In the quasiclassical approximation we analyze the dependences of the resistivity ρ and Hall field on the magnetic field orientation and intensity in layered conductors with quasi-2D energy spectrum of arbitrary form. The Shubnikov-de Haas amplitudes are shown to drop abruptly and the smooth part of magnetoresistance…
The recovery of valuable proteins (like proteolytic enzymes) from nonconventional biological sources by using modern separation techniques is becoming increasingly important because of their high commercial potential. In the present investigation, isolation of proteins from human placental extract by using the continu…
The electric-field dependence of the correlation region induced by a surface potential in cholestric liquid-crystal phases is considered theoretically. Based upon arguments given for the helicoidal and cubic blue phases I and II, it is argued that recent experimental results on blue phase III rule out a cubic or icosa…
Cellulose tri-n-alkanoates, fully substituted ester-type derivatives of cellulose, having acyl groups with n carbon atoms (3 < n < 18), are prepared and their thermal behaviour studied. It is found that samples of cellulose tri-n-alkanoates with n > form a novel thermotropic mesophase, characterized by a low birefring…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoinduced dissociation and desorption of nitrous oxide on a platinum(111) surfaceJ. Kiss, D. Lennon, S. K. Jo, and J. M. WhiteCite this: J. Phys. Chem. 1991, 95, 21, 8054–8059Publication Date (Print):October 1, 1991Publication History Published online1 May 2002Published i…
Abstract Polyanilines have been known for over one hundred years. Recent studies of this chemically flexible polymer have demonstrated unusual chemical, electrical, and optical phenomena, both in insulating forms and conducting forms. The polyanilines differ substantially from earlier studied polyacetylene, polythioph…
Analytical expressions describing double-scattering intensities of the Compton and Rayleigh effects (Compton-Compton, Compton-Rayleigh, Rayleigh-Compton, and Rayleigh-Rayleigh contributions), are deduced in the framework of the transport theory for an infinitely thick sample irradiated with collimated monochromatic ra…
The effect of incorporating mullite into alumina by an infiltration process on the mechanical properties was investigated. Data for Young's modulus, strength, and fracture toughness for various composite compositions were compared with those for the unreinforced matrix (alumina). Measurements of Young's modulus by a r…
Electromagnetic interference (EMI) shielding characteristics of nitrile rubber composites filled with short-carbon fibre (SCF), conductive car bon black (Conductex™ 900), and filler blend (SCF + Conductex™ 900) have been studied. The measurements of shielding effectiveness (SE) were carried out in two different freque…
Mullite and ZrO 2 ‐mullite ceramics have been prepared by tape casting mixtures of Al 2 O 3 , quartz, and ZrO 2 powders and subsequent reaction sintering. Tape casting leads to homogeneous, high‐density green materials with good sinterability. The design of a thermal cycle which favors densification with respect to mu…