Materials Literature
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The temperature dependence of the nucleation density of Chemical Vapor Deposition diamond was carefully investigated by ellipsometric monitoring. Substrates were pre-treated by rubbing with diamond powder and then by wiping off the residual powder until visually clean. Nucleation density was greater than 10 10 /cm 2 i…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRelative strength of 4d vs 5d .delta.-bonds: rotational barriers of isostructural molybdenum and tungsten porphyrin dimersJames P. Collman, J. Michael Garner, Robert T. Hembre, and Yunkyoung HaCite this: J. Am. Chem. Soc. 1992, 114, 4, 1292–1301Publication Date (Print):Febru…
Abstract The system studied in this work is a dilute solution of rod‐like molecules under simple shear flow and near a hard wall. The time evolution of the probability density function is described by a diffusion equation; particle trajectories that correspond to this equation are generated by stochastic methods. Seve…
Recently it has been suggested that thermal electronic properties of magnetic mixed valence systems have to be studied by using an effective Hamiltonian different from the Heisenberg one, so successful for localized electron systems. The object of this paper is to specify conditions of validity of both Hamiltonians. I…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDissociation behavior of poly(fumaric acid) and poly(maleic acid). 3. Infrared and ultraviolet spectroscopySeigou Kawaguchi, Toshiaki Kitano, and Koichi ItoCite this: Macromolecules 1992, 25, 4, 1294–1299Publication Date (Print):February 1, 1992Publication History Published…
Dense α‐sialon materials were produced by hot isostatic pressing (HIP) and post‐hot isostatic pressing (post‐HIP) using compositions with the formula Y x (Si 12–4.5 x , Al 4.5 x )‐(O 1.5 x ,N 16–1.5 x ) with 0.1 ≤ x ≤ 0.9 and with the same compositions with extra additions of yttria and aluminum nitride. X‐ray diffrac…
Temperature variations of the refractive index on have been studied in single crystals of ferroelectric perovskites with diffuse phase transitions, with a different degree of ordering and also in the nonferroelectric crystals with pyrocphlore-type structure. Ferroelectric contribution δp to the index of refraction was…
Electron-spin-resonance (ESR) spectra of 11B3(i=3/2) in neon, argon, and krypton, 10B3(i=3) in argon, and 27Al3(i=5/2) in argon, krypton, and methane matrices at 3–30 K indicate that both trimers contain one unpaired electron (S=1/2) and three equivalent nuclei (D3h symmetry). The derived hyperfine (hf) parameters for…
Tricycloquinazoline, a molecule of both biological and physical interest, has been found to function as the core fragment for a remarkable new family of discotic mesogens, which have C3 symmetry and six aliphatic side chains. Eight representative homologous 2,3,7,8,12,13-hexa(thioalkoxy)tricycloquinazoline derivatives…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolution IR spectroscopic studies of cis-dioxomolybdenum(VI) complexesJoseph Topich and John O. Bachert IIICite this: Inorg. Chem. 1992, 31, 3, 511–515Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February 1992http…
A flexural strength of up to 1 GPa was achieved in SiC‐AIN materials and is attributed to a dense, equiaxial grain structure of the 2H(δ) SiC‐AIN solid solution, with a relatively uniform grain size of ∼ 1 μm. The strength was found to decrease with increasing grain size. While the β→α phase transformation and the for…
Abstract Electrochemical polymerization of 1 H ,7 H ‐pyrrolo[2′,3′:4,5]thieno[3,2‐ b ]pyrrole and 4 H ‐dithieno[3,2‐ b ;2′,3′‐ d ]pyrrole in CH 3 CN + 0,1 M p ‐toluenesulfonate and tetraethylammonium perchlorate, respectively, yields polymers with a conductivity of ca. 5 S/cm. Electrochemistry and elemental analysis i…
The experimental vaues of Inelastic Mean Free Path (F) of electrons in noble metals (Ag, Au, Cu) are determined in the electron energy range 150-2000 eV. The method used consists of the measurements and theoretical calcuations of the coefficient of elastic backscattering of electrons from a solid surface ne . The obta…
K 2 Sn 2 S 5 and K 2 Sn 2 Se 5 were prepared by reacting stoichiometric powdered mixtures of the binary compounds K 2 S or K 2 Se with Sn and the corresponding chalcogen at 1070 K, followed by slow cooling of the melt. The two compounds are isostructural and crystallize with the Tl 2 Sn 2 S 5 structure type, s.g. C 2/…
Dielectric biaxiality plays an important role in the electric field behaviour of ferroelectric liquid crystal devices, providing the necessary driving force for AC field stabilization and playing an important role in device dynamics. The static electric permittivities have been measured as a function of temperature fo…
<div class="htmlview paragraph">Measurements of oxygen storage capacity (OSC) and HC conversion efficiency for 17 catalysts were carried out in the laboratory. All catalysts with steady state HC efficiency below 90% were found to have roughly equivalent and very low capacities to store oxygen. However, catalyst…
We have investigated the high pressure behavior of InSe by x-ray powder diffraction and optical measurements. The rhombohedral γ-polytype of InSe (space group R3m) exhibits a strongly anisotropic compressibility characteristic of the layer-type structure. Mode Gruneisen parameters of intralayer modes have been determi…
Conventional shear‐lag analyses of matrix cracking and debonding in uniaxial composites loaded in tension predict that the matrix stress varies only very slowly with position except near existing cracks. It therefore follows that the location of subsequent cracks is very sensitive to minor local variations in matrix s…
It is shown that nonlinear segregation effects (saturation, interaction of species) lead to nonlinear grain-boundary penetration plots. If the diffusion penetration depth is larger than a critical value, the concentration profiles become linear. The sign of the curvature and the deviation from a straight concentration…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteraction and catalytic decomposition of 1,1,1-trichloroethane on high surface area alumina: an infrared spectroscopic studyTodd H. Ballinger and John T. Yates Jr.Cite this: J. Phys. Chem. 1992, 96, 3, 1417–1423Publication Date (Print):February 1, 1992Publication History P…