Materials Literature
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The ESR spectra of vanadyl acetylacetonate and tetraphenylporphyrin have been studied in various liquid solvents and frozen glasses. The spectra have been analyzed and the components of the g tensor and of the vanadium hyperfine interaction tensors have been determined, and for the porphyrin the nitrogen extrahyperfin…
Bayerite, fl-AI(OH)3, and boehmite, 7-A1OOH, both with crystallite sizes of some tenths of a micron, were used for this investigation.
Abstract On oxidation of graphitic carbon, acidic surface oxides (or hydroxides in the presence of water) are formed at the boundaries of the carbon layers. It was found that the reaction of oxygen with microcrystalline carbon at 400–450°C yields four groups of different acidities. One strongly acidic group and one we…
The barrier‐layer model previously proposed to explain the anomalous increase in resistivity that occurs in doped BaTiO 3 has been reexamined in the light of data obtained from more recent experiments. The picture thus obtained describes correctly and quantitatively the resistivity anomaly and the frequency and voltag…
The interaction between particles and an advancing solid-liquid interface has been investigated both experimentally and theoretically. For each particular type of particle, a ``critical velocity'' was observed, below which the particles are rejected by the interface, and above which they are trapped in the solid. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular Orbital View of Chemisorbed Carbon MonoxideGeorge BlyholderCite this: J. Phys. Chem. 1964, 68, 10, 2772–2777Publication Date (Print):October 1, 1964Publication History Published online1 May 2002Published inissue 1 October 1964https://pubs.acs.org/doi/10.1021/j10079…
Abstract The nature of the electronic-vibrational states of a d9 ion in an octahedral complex is discussed in term s of an adiabatic model in which th e electronic motion follows the nuclear motion exactly. Expressions for the g-values and the hyperfine structure parameters of the e.s.r. spectrum at high and low tempe…
The resistance of VO2 through the semiconductor-to-metal transition has been measured as a function of hydrostatic pressure. The transition has been studied in pure and partially hydrated single crystals of VO2 and in powdered VO2. The temperature of the transition is shifted by less than 0.5 C° by pressures up to 6×1…
The effect of very high pressure has been studied on the electronic structure of some fused-ring aromatic hydrocarbons. The material most thoroughly studied is pentacene. Observations include optical absorption of the low-energy peaks and electrical resistance. The optical absorption peaks of tetracene and pentacene s…
The magnetic and structural characteristics of 11 intermetallic compounds represented by the formula LnNi are reported. The five compounds with Ln=Dy, Ho, Er, Tm, and Y are isomorphous and occur in the FeB structure. The others, with Ln=Ce, Pr, Nd, Sm, Gd, and Tb, form in the CrB structure, YNi and CeNi exhibit only P…
The effect of pressure to 300 kbar has been measured on the volume and on the lattice parameters ($c$ and $a$) of the hcp magnesium lattice. The $a$ axis compresses in a regular manner, but the $c$ axis compresses relatively rapidly to 70 kbar, then becomes continuously more incompressible in the range 70-120 kbars, w…
Measurements of the change in thermal conductivity of high-purity single-crystal GaAs were made upon 2-MeV electron irradiation and annealing. Two GaAs samples were irradiated at maximum temperatures of 100 and 80\ifmmode^\circ\else\textdegree\fi{}K. A linear increase in the additive thermal resistivity near 50\ifmmod…
Methods for treating boundary-value problems involving helicon waves (whistlers in solids) are developed and used for infinite plates and cylinders. The magnetoplasma inside the solid is assumed to be "driven" by means of external coils, which set up an oscillatory field with sinusoidal variation along the two coordin…
Trapping levels which account for most of the thermoluminescence in natural calcite have been investigated. Results are based on a study of color centers which are shown to be closely associated with the traps involved in thermoluminescence. Optical absorption measurements in a variety of Iceland-spar crystals show th…
The independent-oscillator model fails to predict the dielectric behavior of the high-dielectric-constant materials BaTi${\mathrm{O}}_{3}$, SrTi${\mathrm{O}}_{3}$, and KTa${\mathrm{O}}_{3}$ in certain infrared-frequency regions near the three infrared-active modes. A more general classical model is proposed with mode…
Effects of sample orientation on the hydroxyl absorption of kaolinite can be interpreted in terms of the structure indicated by x-ray investigations, in which the surface hydroxyl groups of each layer are directed toward the oxygen atoms on the surface of the next layer.
Abstract A theory is proposed which enables activation energies for creep (ΔHc), and stress relaxation (ΔHs,r) to be calculated when the limiting moduli vary with temperature. The theory explains the agreement obtained by Kê between ΔHc, ΔHs.r. and the activation energy for internal friction ΔHi, f. for the grain boun…
Abstract Bei der Oxydation graphitischen Kohlenstoffs bilden sich an den Rändern der Kohlenstoffschichten saure Oberflächenoxyde (oder ‐hydroxyde bei Anwesenheit von Wasser). Mit mikrokristallinem Kohlenstoff ergab sich, daß bei der Reaktion mit Sauerstoff bei 400 bis 450°C vier Gruppen unterschiedlicher Acidität ents…
SOME of the most common failure modes of low voltage aluminum electrolytic capacitors are the result of slow chemical and electrochemical reactions on the electrode surfaces. These reactions are an inherent property of the A1/A12O3/ electrolyte system. In this paper the relationship between particular failure modes an…
Near-infrared studies indicate the a bsence or n car-absence of isolated cis and te rminal double bonds in rubber vulcanized either with or without acccleraLors, as well as in t he squ alene-sulfur r eaction product. The usc of purifi ed n atu r al rubber indicates a Jl eW a bsorption near 6.1 J1-on r eaction with s u…