Materials Literature
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Abstract Thin green clay layers and lenses in the lower part of the Lower Oligocene Kerkom Sand near Aardebrug, east of Louvain in Belgium, were found to consist of glauconitic illite. This mineral contains about equal amounts of iron and aluminium oxides (14%) and is therefore intermediate in chemical composition bet…
Huntite structure compounds with the formula REFe3B4O12 (RE = La3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+ and Y3+) have been synthesized. X-ray powder diffraction patterns and cell parameter data are reported. The infrared spectrum confirms the triangular coordination of boron in these compounds.
1. The function of the wild-type alleles of the pleiotropic mutants cysB and cysE of Escherichia coli was investigated. 2. The wild-type allele cysB(+) is dominant to the mutant allele cysB in stable and transient heterozygotes. 3. The wild-type allele cysE(+) is dominant to the mutant allele cysE, as predicted. 4. Su…
The importance of accurate high-temperature thermodynamic data for the study of anharmonic effects in solids is discussed, and an adiabatic calorimeter for the measurement of heat capacities in the temperature range 25-500 °C is described. The precision of the heat capacity data is about ±0·1% for T < 400 °C and ±0·2%…
Thermally crystallized glasses of compositions (Li 2 ,O 2 , MgO).Al 2 O 3 .nSiO 2 were studied by X‐ray powder diffraction methods. High‐quartz solid solution phases developed at relatively low temperatures and, for n 3.5, transformed at higher temperatures to keatite solid solution phases. Associated phases, if prese…
The dislocation arrangement in the stress-applied condition of copper single crystals deformed in tension at 78°K was pinned by irradiating with a dose of 1018 n/cm2 fast neutrons at 4·2°K or 20°K. Transmission electron microscope studies of the primary glide plane showed that significant differences exist between the…
The acoustic properties of various types of commercial vitreous silica have been studied as functions of thermal treatment and impurity-ion concentrations. The properties studied include density, shear-wave attenuation, shear and dilatational wave velocities, and elastic constants. The measurements of acoustic propert…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new metal cluster system containing a cube of metal atomsL. E. McCandlish, E. C. Bissell, D. Coucouvanis, John P. Fackler, and Kerro KnoxCite this: J. Am. Chem. Soc. 1968, 90, 26, 7357–7359Publication Date (Print):December 1, 1968Publication History Published online1 May 2…
The high-temperature phase transition in KH2PO4 has been investigated by differential thermal analysis, thermogravimetric analysis, proton magnetic resonance and relaxation, infrared spectroscopy, and x-ray and quasielastic cold-neutron scattering. The transition is not connected with a static breaking up of the hydro…
Small-angle X-ray scattering is shown to be an effective technique, complementary to mechanical and thermal methods, for the study of structural ordering in polyurethane elastomers. Wide variations in intensity were found for different sample compositions and are interpreted in terms of the degree of hard segment aggr…
A number of techniques have been used to study structural organization and transitions in polyether- and polyester-based urethane elastomers. Scanning thermal methods reveal three characteristic transitions common to samples of varying composition, namely, the major glass transition and two higher transitions believed…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of some pyrochlore-type oxides of platinum(IV) at high pressureHenry R. Hoekstra and F. GallagherCite this: Inorg. Chem. 1968, 7, 12, 2553–2557Publication Date (Print):December 1, 1968Publication History Published online1 May 2002Published inissue 1 December 1968ht…
The Raman and infrared spectra of single crystals of the nitrates of the alkali metals and silver have been studied at room temperature. The internal vibrations of the nitrate ion and the external vibrations of the crystal lattice are assigned on the basis of a factor-group analysis of the crystal. For the rhombohedra…
The fluorescence spectrum of trivalent europium in the site of C3υ symmetry of polycrystalline Y2O2S:Eu3+ is investigated in the region 4000–9000 Å. Of the total of 363 transitions between the crystal components of the J = 0 to J = 3 states of D5 and those of the J = 0 to J = 6 states of 7F, almost two thirds are obse…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhase transformations in the praseodymium oxide-oxygen system: high-temperature x-ray diffraction studiesD. Arthur Burnham and LeRoy EyringCite this: J. Phys. Chem. 1968, 72, 13, 4415–4424Publication Date (Print):December 1, 1968Publication History Published online1 May 2002…
Infrared absorption by a mineral arises from the vibrations of its constituent atoms, and the frequencies of these vibrations are dependent on the mass of the atoms, the restraining forces of the bonds, and the geometry of the structure. The resultant spectrum of absorption frequencies is a characteristic property of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPerfluoroalkylsilver compoundsWilliam Taylor Miller Jr. and Robert J. BurnardCite this: J. Am. Chem. Soc. 1968, 90, 26, 7367–7368Publication Date (Print):December 1, 1968Publication History Published online1 May 2002Published inissue 1 December 1968https://pubs.acs.org/doi/1…
Abstract An application of TGA technique to elucidate the chain reaction mechanism of cellulose pyrolysis is discussed. The mathematical expressions for isothermal kinetics are modified for use with temperature‐programmed kinetics. It is shown that in temperature‐programmed kinetics, the initial reaction should theore…
The very complicated formulae which relate the components of the complex refractive index of a thin film to the measurable optical reflection and transmission coefficients have been put into a much simpler form. This greatly simplifies the programming for a computer solution of the equations, and also leads to some us…
The author's 1962 treatment of the surface structure of water and ice is reconsidered in the light of new theoretical information on the quadrupole moment of the water molecule and on the structure of liquid water. Electrostatic effects are explicitly taken into account and it is concluded that the principal mechanism…