Materials Literature
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The in-frame fusion between two oligomeric enzymes, beta-galactosidase and galactose dehydrogenase, is described. The lacZ gene was fused to the 3' end of the galdh gene with a linker encoding only three amino acids. The purified artificial bifunctional enzyme displayed the enzymic activity of both gene products. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMethanol synthesis catalysts based on cesium/copper/zinc oxide/metal oxide (metal = aluminum, chromium, gallium): genesis from coprecipitated hydrotalcite-like precursors, solid-state chemistry, morphology, and stabilityJohn G. Nunan, Paul B. Himelfarb, Richard G. Herman, Ka…
Abstract The structural damage produced by dry grinding and acid leaching of chrysotile was studied by transmission and scanning electron microscopy, infrared spectroscopy, X-ray powder diffraction, and thermogravimetric analysis. Severe dry grinding converted the chrysotile fibers into fragments having strong potenti…
The interactions of CO 2 with a clean Cu(110) surface have been studied both in an ultrahigh-vacuum surface analytical chamber and in an attached, high-pressure cell. No adsorption or dissociation of CO 2 was measured for exposures up to 350 L at 110 K and 250 K. Exposures of 65 to 650 Torr of CO 2 at 400-600 K led to…
During torsional deformation of A1 (purity 99·7%) with 0·1 or 2mm grains at 400°C and 0·2s-1, the flow curve rises to a steady-state plateau of 18 MPa for ∊ = 0·5-3·0 and then gradually decreases by 27% by ∊ = 20, after which it remains constant at about 12°5 MPa. The decrease after the traditional steady-state regime…
ABSTRACT Ten shale samples of Frio and Vicksburg (Tertiary) overpressured shales from Brazoria and Hidalgo Counties, Texas, were examined by transmission electron microscopy (TEM) techniques. Initially, illite and smectite (with some mixed-layer component?) are present in subparallel domains, with smectite packets dom…
The electron energy-loss spectrum due to surface plasmon excitation is studied for objects with arbitrary shape and dielectric constant. Both classical and quantum-mechanical approaches are used. The results are useful for prediction of the energy loss spectrum obtained when using a highly convergent incident electron…
Mineralization processes in the body are controlled by physicochemical and cellular regulation of hydroxyapatite (HA) nucleators and inhibitors. The chemical mechanism of action of HA inhibitors has been studied in vitro using solution pH-stat techniques or Types I and II collagen gel diffusion systems. Three biologic…
Abstract Accurate dynamic mechanical measurements have been performed on semicrystalline isotactic polypropylene over wide ranges of temperature and frequency. A mechanical model has been used to analyze experimental results in order to separate the behavior of amorphous and crystalline phases. The two main α and β re…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPerforated monolayers: design and synthesis of porous and cohesive monolayers from mercurated calix[n]arenesMichael A. Markowitz, Vaclav Janout, David G. Castner, and Steven L. RegenCite this: J. Am. Chem. Soc. 1989, 111, 21, 8192–8200Publication Date (Print):October 1, 1989…
Abstract Hydrotalcite-like compounds, described by the formula [Zn 1- x Al x (OH) 2 ][(CO 3 ) x /2 · nH 2 O], were prepared by coprecipitation methods at 80°C and characterized by bulk chemical analysis, X-ray powder diffraction (XRD), nuclear magnetic resonance (NMR), and scanning-transmission electron microscopy (ST…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIn situ photoluminescence of titania as a probe of photocatalytic reactionsMasakazu Anpo, Masanori Tomonari, and Marye Anne FoxCite this: J. Phys. Chem. 1989, 93, 21, 7300–7302Publication Date (Print):October 1, 1989Publication History Published online1 May 2002Published ini…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthetic and structural studies of a series of soluble cerium(IV) alkoxide and alkoxide nitrate complexesWilliam J. Evans, Timothy J. Deming, Jeffrey M. Olofson, and Joseph W. ZillerCite this: Inorg. Chem. 1989, 28, 21, 4027–4034Publication Date (Print):October 1, 1989Publi…
Abstract The colloidal dispersions of the palladium-platinum bimetallic clusters were prepared by refluxing the solution of PdCl6 and H2PtCl2 in water/ethanol in the presence of poly(N-vinyl-2-pyrrolidone). The electronic absorption spectra and the transmission electron micrographs show the formation of an alloy in th…
A set of complex dielectric, piezoelectric and elastic constants has been measured in a temperature range between 4.2 K and the Curie point on undoped and Fe-doped PZT samples. All samples show a pronounced relaxation below 400 K which is attributed to domain wall vibrations according to an earlier developed model. A…
Abstract The effects of pendant groups on gas transport were investigated using a series of substituted polystyrenes. Permeability coefficients were measured at 35°C and 1 atm for He, N 2 , O 2 , CH 4 , and CO 2 , and diffusion coefficients were calculated from time lag data. The absolute permeabilities for the polyst…
Structural images of the stacking faults in β‐SiC were obtained with a high‐resolution electron microscope. Stacking faults initially present in β‐SiC powder particles were eliminated as grain growth proceeded at elevated temperatures.
Diffusion of water into silica glass was measured in the temperature range of 200° to 750° by treating the glass in air containing a constant water vapor pressure and analyzing the concentration profile using a Fourier transform infrared spectrometer. In the short‐time diffusion heat treatments, the surface concentrat…
An aqueous injection molding process based on the gelling properties of certain naturally occurring polysaccharides, in particular agar, and its purified derivative, agarose, is described. The materials form nonviscous solutions at temperatures near 100°C which solidify to rigid gels upon cooling below the so‐called g…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOn the physical meaning of the Kwei equation for the glass transition temperature of polymer blendsAnshyang A. Lin, T. K. Kwei, and Arnost ReiserCite this: Macromolecules 1989, 22, 10, 4112–4119Publication Date (Print):October 1, 1989Publication History Published online1 May…