Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface characterization of copper(II) oxide-zinc oxide methanol-synthesis catalysts by x-ray photoelectron spectroscopy. 1. Precursor and calcined catalystsYasuaki Okamoto, Kiyotaka Fukino, Toshinobu Imanaka, and Shiichiro TeranishiCite this: J. Phys. Chem. 1983, 87, 19, 37…
The intrinsic crack tip processes of either propagation by cleavage or blunting by the nucleation of dislocations from the nonlinearly stressed region at the crack tip have been simulated by a molecular dynamics approach in alpha-iron and in copper, utilizing the Johnson and Morse potentials, respectively, and a new f…
Electron-energy-loss spectra have been measured in the region of the $K$ edges in graphite and hexagonal boron nitride. The fine structure is found to be strongly dependent on the crystal orientation and momentum transfer. Angular distributions of peaks in the spectrum have been recorded from crystals with the $c$ axi…
Abstract As a nondestructive method of evaluation, we have used integrated optics to investigate thin films (<8 μm) of polyamic acid and polyimide as a function of molecular weight, initial imidization temperature, method of imidization, and annealing treatment. Polyamic acid films were found to exhibit a large opt…
We have developed a computer program by means of which a two-dimensional soap froth may be simulated. This system is of interest in connection with theories of grain growth in polycrystalline solids, but only limited and somewhat contradictory experimental statistical data have hitherto been available. We present prel…
Two industrial portland cement clinkers from the same kiln, with different setting rates, were texturally characterizated by reflected light microscopy. They showed remarkable mineralogic and textural differences which arised during their distinct cooling processes, according to the interpretation of their textures.
Physical properties of Villamayor sandstone (Salamanca), and especially porosity, water absorption and capillary flow through rock are studied in relation to its lithological characteristics. Laboratory weatherability tests (wetting-drying, freezing-thawing, and salt crystallisation) shows the susceptibility to destru…
The present paper deals with aspects concerning the conditions to be fulfilled by raw materials and manufacturing process of cements containing components other than clinker and setting regulator. It deals also with proper conditions for the utilization of these cements, as well as with the knowledge of the interrelat…
A comparative study has been done about the use of three methods: Microscopic, Dissolution of Phases and X-Ray Diffraction, for the determination of the mineralogical composition of clinker, XRD appears (just as it is shown in this paper) as a complicated method which does not guarantee a good determination of C3A. Th…
This discussion commences with some general comments on the energy crisis and its impact on the cement industry, with the corresponding coal reconversion problems. Three factors are highlighted where saving has been centered: technological process, raw materials and finished product, emphasizing the interest of latter…
There having been established in a previous publication the criteria which guide the designing of a system of simulation, in this work is presented the carrying out, in our Department, of a versatile installation, of a modular type which allows, in its whole, to carry out a large part of the experiments of alteration…
In this work, which is a follow-up of others, the evolution of structural features of enriched fraction (attacked-hydrated cement) is studied by DRX, extracted from one of the mortar prims (1 : 3) of 1 X 1 X 6 cm of the various series of test specimens made with a Portland cement (cement 3) and mixtures cement 3/slag…
Oxygen‐diffusion coefficients were determined in single crystals of MgO and α‐Fe 2 O 3 by exchanging the samples with 18 O enriched gas at 1 atm and measuring 18 O profiles using a proton activation technique. For MgO, in the temperature range 1580 to 1820 K, the diffusion coefficient is represented by:
The space-group frequency for approximately 30 000 organic compounds in the NBS Crystal Data Identification File has been calculated for each of the 230 space groups. 75% of the compounds have been reported in only five space groups: P21/c (36.0%), P{\bar 1} (13.7%), P212121 (11.6%), P21 (6.7%) and C2/c (6.6%). In con…
A secondary battery utilizing polythiophene films as cathode and anode active materials in an electrolyte of TBABF 4 /MeCN is studied. The cell potential, energy density and maximum power density (based on the weight of cathode and anode films) are observed to be 3.1 V, 93 Wh/kg and 89 kW/kg, respectively, for the dop…
Abstract The pinning site inhomogeneities interacting with a domain wall are characterized by the maximum restoring force, f, acting on an area A of domain wall. The critical field, H 0, required to release this area from the pin is given by f/2IA where I is the magnetic moment per unit volume. The area A is not indep…
Replicate samples of Phragmites communis roots coated with hydrous iron oxide were analyzed for internal and external Fe using the dithionite‐citrate‐bicarbonate technique (hot DCB), a modified DCB technique (cold DCB), Ethylenediamine tetraacetic acid (EDTA), Diethylenetriamine pentaacetic acid (DTPA), and a total Fe…
Diffraction by an arbitrarily oriented planar grating with slanted fringes is analyzed using rigorous three-dimensional vector coupled-wave analysis. The method applies to any sinusoidal or nonsinusoidal amplitude and/or phase grating, any plane-wave angle of incidence, and any linear polarization. In the resulting (c…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAliphatic hydroxylation catalyzed by iron porphyrin complexesJohn T. Groves and Thomas E. NemoCite this: J. Am. Chem. Soc. 1983, 105, 20, 6243–6248Publication Date (Print):September 1, 1983Publication History Published online1 May 2002Published inissue 1 September 1983https:…
An equation describing the initial magnetisation curve and hysteresis loops of ferromagnetic materials has been derived theoretically based on a mean field approximation. The mutual interaction of the moments is expressed as a coupling coefficient and a restraining force on the motion of the domain walls, caused by th…