Materials Literature
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A structural model of ZnO in the cumulant-expansion formalism has been studied with X-ray intensities measured on a spherical crystalat293 and,473 K. In the least-squares refinements, the thermal vibrations appear isotropic for both atomic species at the two temperatures investigated. The equivalent isotropic temperat…
The interaction of various alkenes with gold electrodes has been studied using surface-enhanced Raman spectroscopy (SERS). Large decreases, from 70 to 140/cm, were observed in the C-C double bond and C triple bond C stretching frequencies upon adsorption which are attributed to adsorbate-surface bonding involving thes…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDimagnesium cobalt(I) pentahydride, Mg2CoH5, containing square-pyramidal pentahydrocobaltate(4-) (CoH54-) anionsP. Zolliker, K. Yvon, P. Fischer, and J. ScheferCite this: Inorg. Chem. 1985, 24, 24, 4177–4180Publication Date (Print):November 1, 1985Publication History Publish…
A critical analysis is given of the EPR spectrum exhibited by the rare-earth S-state ions, Gd3+ and Eu2+, in glassy and disordered polycrystalline materials. The analysis of this spectrum and of its previous interpretations is based on (a) a set of criteria derived from a wide range of experimental EPR and optical dat…
The thermal response of a polymer composite material undergoing decomposition has been modeled. A one-dimensional transient thermal model with an n th order ap proximation for the rate of decomposition was applied. The model was tested by ex perimentally measuring the temperature profiles during decomposition for a gl…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterlayer chemistry between thick transition-metal oxide layers: synthesis and intercalation reactions of K[Ca2Nan-3NbnO3n+1] (3 .ltoreq. n .ltoreq. 7)A. J. Jacobson, Jack W. Johnson, and J. T. LewandowskiCite this: Inorg. Chem. 1985, 24, 23, 3727–3729Publication Date (Prin…
The symmetry and stability of icosahedral incommensurate structures and generalized two-dimensional Penrose pentagonal structures are studied. The crystallographic properties of Penrose lattices are described by five-dimensional (5D) super space groups, and the icosahedral structures are described by 6D space groups,…
The viscosities of suspensions of sterically stabilized (hard) silica spheres in cyclohexane are reported as a function of shear rate (γ̇) and volume fraction (6×10−4<φ<0.6). The shear thinning scales according to (ηr−η∞)/(η0−η∞) =1/(1+1.31ηγ̇a3/kT) with limiting low and high shear viscosities described…
Starting from an exact expression for the Helmholtz free-energy functional of an inhomogeneous classical liquid, an approximate functional is presented which depends on a weighted average of the physical density. It retains the nonlocal character of the exact expression, but requires only the properties of the homogen…
The author reviews the present understanding of the electronic, geometric and chemisorption properties of metal oxide surfaces. It is restricted to experimental and theoretical studies of single-crystal oxide surfaces since only for those systems has it been possible to correlate surface properties with specific site…
Abstract The rate of oxygen permeation through La1−xSrxCo1−yFeyO3−δ was found to increase with an increase in Sr or Co content, showing that the permeability was mainly controlled by the amount of oxygen vacancies. The results obtained indicate that mixed conductive perovskite-type oxides are promising materials for o…
Data obtained in recent years on the epoxidising agents and the mechanism of their interaction with olefins are surveyed. Different types of hydroperoxides as well as certain short-lived epoxidising intermediates of the molecular and radical types functioning in situ are examined. The results of the stereospecific epo…
We present measurements and analysis of the basal thermal conductivity for two dichalcogenides: $1T$-Ta${\mathrm{S}}_{2}$ and $2H$-Ta${\mathrm{Se}}_{2}$. The data which are obtained for the first time cover the range 80-400 K. The lattice contribution is important for each compound and possesses specific features rela…
A description is given of the use of the Fresnel zone plate as a focusing or a frequency-filtering device at millimeter wavelengths. Sample design data are given, as well as references to prior results. A newer type of zone plate is discussed which employs two dielectrics of equal thickness to produce a flat zone plat…
The order parameter and anisotropy (elongation) of the configurations of a nematic polymer in the nematic phase are calculated. At low temperatures exponentially rapid growth of chain dimensions as a function of inverse temperature is found. In the nematic direction the chain eventually adopts a rod-like state. The th…
Silicon surface reconstructions are directly observed in profile by high-resolution transmission-electron microscopy. Low-energy surface facets are formed at edges by in situ annealing of a 〈110〉 thin specimen at an ambient pressure of ${10}^{\mathrm{\ensuremath{-}}9}$ Torr. As well as 〈111〉, 〈100〉, and 〈110〉 reconstr…
We report the first realization of a quasiperiodic (incommensurate) superlattice. The sample, grown by molecular-beam epitaxy, consists of alternating layers of GaAs and AlAs to form a Fibonacci sequence in which the ratio of incommensurate periods is equal to the golden mean $\ensuremath{\tau}$. X-ray and Raman scatt…
A molecular theory for smectic A liquid crystals is described which starts from an expression for the internal energy in terms of the orientational and translational order parameters. This expression is used to determine the single particle distribution function by invoking the molecular field approximation. The relat…
The application of x-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) to the solution of complex real world catalyst problems is often difficult and frustrating. Three recent developments in this laboratory have greatly aided in the solution of such problems. These are 1) a dual anode x-ray s…
An attempt is made to study the heating rate dependence of the peak and position of the maximum depolarization current in ITC measurements. It is observed that the area under the ITC curve, where depolarization current is plotted as a function of time remains unchanged at different heating rates. Mathematical equation…