Materials Literature
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The three lowest energy levels of ${\mathrm{Ho}}^{3+}$ in ${\mathrm{LiYF}}_{4}$ are determined by submillimeter EPR spectroscopy. The ground state is a ${\ensuremath{\Gamma}}_{3,4}$ doublet. The next excited levels are two ${\ensuremath{\Gamma}}_{2}$ singlets at 6.8 and 23.8 ${\mathrm{cm}}^{\ensuremath{-}1}$. The ${g}…
The reflection spectra of BiI s single crystals were measured between 1.5 and 5.5 eV at 6, 77 and 286 K. A Kramers-Kronig dispersion analysis of the data was made, and the intrinsic absorption coefficient and the real and imaginary parts of the dielectric constants were calculated. The large peak at 2.0 eV is ascribed…
Unpolarized specular reflectance spectra at near-normal incidence were measured in the silicates olivine, pyroxene, spinel and Al-garnet in the photon energy range 4–14 eV at 300°K, and the optical and dielectric functions were obtained from the reflectance by Kramers-Kronig analysis. The spectra indicate that these m…
For compounds of the type YCo5xNi5−5x the saturation moment and Curie temperature were determined. For large Co concentrations the rigid-band approach applies. The magnetic splitting of the 3d band collapses near x=0.2. Magnetic isotherms were studied at 4.2 K as a function of concentration. The form of the virgin mag…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilane reductions in acidic media. VII. Aluminum chloride catalyzed hydrogen-halogen exchange between organosilanes and alkyl halides. An efficient hydrocarbon synthesisMichael P. Doyle, Charles C. McOsker, and Charles T. WestCite this: J. Org. Chem. 1976, 41, 8, 1393–1396Pu…
Abstract The infrared and Raman spectra of polycrystalline PbHPO 4 , PbHAsO 4 , CaHPO 4 , and BaHPO 4 were measured at room temperature in the range between 4000 and 30 cm −1 , and the temperature dependence of the dielectric constant of these materials was studied. The OHO hydrogen bonds in PbHPO 4 and PbHAsO 4 are…
A theoretical and experimental study has been carried out on extrudate swell B, especially the influence of rheological properties and applied take-up force on the emerging melt. The problem is analyzed in terms of (1) dimensional analysis, (2) force–momentum balances, (3) partially constrained elastic recovery. Analy…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharge-transfer polymers containing 7,7,8,8-tetracyanoquinodimethan and tetrathiafulvaleneW. R. HertlerCite this: J. Org. Chem. 1976, 41, 8, 1412–1416Publication Date (Print):April 1, 1976Publication History Published online1 May 2002Published inissue 1 April 1976https://pub…
A mathematical model to describe the contamination of steel surfaces by 60Co in high-temperature water is developed. The model assumes that 60Co is incorporated into the growing oxide film on the steel, so that the contamination rate is governed by corrosion kinetics. Release to inactive coolant is controlled by solid…
Impurity has two kinds of effects on the phase transition involving the formation of a charged density wave in a conductor. One is to break the coherent electron-hole pair and thus lower the transition temperature. The other is to create sufficient fluctuation to smear the transition, even in three-dimensional systems…
The solubility of quartz in water has been determined by a weight-loss technique in the range 500 degrees -900 degrees C and 1,000-10,000 bars. From the data, approximate values of delta H and delta V for the silica-water complex-forming reaction have been calculated, and assuming the complex to have the form SiO <sub…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAxial ligation modes in iron(III) porphyrins. Models for the oxidized reaction states of cytochrome P-450 enzymes and the molecular structure of iron(III) protoporphyrin IX dimethyl ester p-nitrobenzenethiolateS. C. Tang, S. Koch, G. C. Papaefthymiou, S. Foner, R. B. Frankel…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolycyclic K-region arene oxides. Products and kinetics of solvolysisJohn W. Keller and Charles HeidelbergerCite this: J. Am. Chem. Soc. 1976, 98, 8, 2328–2336Publication Date (Print):April 1, 1976Publication History Published online1 May 2002Published inissue 1 April 1976ht…
The exact distribution and moments are derived for the length (mass) aggregate of fibers to be found within an interval L of a random fiber array as a direct function of the constituent fiber length distribution and the interval size L. The moments immediately facilitate computation of irregularity in terms of the coe…
Abstract The inflation and growth kinetics of bubbles in thermoplastic structural foams are discussed in some detail using a model which assumes the initial existence of very small voids in the pressurized polymer melt. The effects of a drop in external pressure, the presence of a distribution of bubble sizes, and the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEsterification by alkylation of carboxylate salts. Influence of steric factors and other parameters on reaction ratesPhilip E. Pfeffer and Leonard S. SilbertCite this: J. Org. Chem. 1976, 41, 8, 1373–1379Publication Date (Print):April 1, 1976Publication History Published onl…
Abstract Es wurden mit einem Lichtstreuphotometer die Orientierungs‐ und Dichtefluktuationen in den amorphen Polymeren «Polycarbonat» (Poly(oxycarbonyloxy‐1,4‐phenylenisopropyliden‐1,4‐phenylen)) und Polystyrol in Abhängigkeit von der Temperatur untersucht. Ferner führten wir ergänzende Messungen an Oligomeren des Pol…
Abstract Electron spin resonance (ESR) spectroscopy is used to investigate the nature of exchange sites on kaolinite. ESR spectra of exchangeable Cu 2+ and Mn 2+ on kaolinite indicate that divalent exchange ions are about 11–12Å apart on kaolinite surfaces and that planar Cu (H 2 O) 4 2+ ions are oriented parallel to…
Abstract The composition of the terpenic alcohol and sterol fractions of the unsaponifiables of ten algal species, five Myxophyceae and five Chlorophyceae , is discussed. The major component of the terpenic fraction is phytol, a diterpenic alcohol. Minor amounts of straight chain and triterpenic alcohols are also pres…
Transmission and scanning electron microscopes were used to investigate the cause of brittleness of electroless copper deposits. Numerous voids were found in brittle deposits, whereas ductile deposits contained significantly fewer voids. These voids were 20–300Å in diameter and randomly distributed within a grain. Low…