Materials Literature
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Dielectric relaxation studies in nematic liquid crystals with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{E}}\ensuremath{\parallel}\stackrel{\ensuremath{\rightarrow}}{\mathrm{n}}$ give the unique opportunity to study a microscopically well-defined kinetic process in a temperature interval extending below ${T}_{g}$. R…
Abstract A few cellulose derivatives were prepared by the reaction of chlorodeoxycellulose (CDC) with ethylenediamine (ED), thiourea, thiosemicarbazide, thioacetamide, and others. These derivatives were found to be able to remove mercuric ions to an extent greater than 99% from a 10 ppm aqueous solution of mercuric ch…
Experimental searches were made for evidences for the charge- or spin-density wave state in the trigonal-prismatic pseudo-linear chain compound ZrTe 5 . Negative evidences for such phase transitions were provided by the absence of lattice modulation, ohmic resistivity at high electric fields, and by temperature and an…
A simple theoretical model for the radiative lifetime of a fluorescent ion in a particle of a powder is described. The model predicts that the lifetime depends on the size of the particle, the density of the powder, and the refractive index of the surrounding medium. For a dilute system of very small particles the lif…
<div class="htmlview paragraph">The formation and oxidation processes of soot particulates in a D. I. diesel engine were investigated under various operating conditions through the measurements of KL factor and flame temperature via the two-color method, whose reliability had been substantiated by a comparative…
The structure of SiO 2 ‐Al 2 O 3 glasses with up to 60 wt% Al 2 O 3 was investigated using the radial distribution function together with the correlation method based on X‐ray scattering intensity data. Radial distribution curves are interpreted on the basis of glass‐in‐glass separation with the constituents of SiO 2…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultinuclear magnetic resonance spectroscopy of spin-admixed S = 5/2, 3/2 iron(III) porphyrinsArden D. Boersma and Harold M. GoffCite this: Inorg. Chem. 1982, 21, 2, 581–586Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published iniss…
The crystal structure of a reverse pleochroic muscovite containing both Fe3+ and Mn3* has been determined by standard single-crystal X-ray methods. The mica has a 2Mr polytype, space grou-p C 2lc. Cellconstants are a :5.1988A esd 0.0021, b = 9.02664 esd 0.0019, c : 20.1058A esd 0.Cf.44, I = 95JE2' esd 0.039, V = 938.7…
The stability criteria for pitting dissolution of metals are examined on the basis of recent results. Pitting dissolution is stable if the local ion concentration buildup at pit sites exceeds a certain critical value, which for pits at noble potentials appears to correspond to the lowest ion concentration required for…
Calculations of diffraction line profiles and Scherrer constants for crystallites whose external shape has cubic symmetry are extended to crystallites of cylindrical shape. The analysis includes the limiting cases of acicular crystals and disks and, to a reasonable degree of approximation in many cases, to hexagonal p…
Abstract The reactivity and related properties of oxygen both in the bulk and on the surface has been investigated for perovskite-type mixed oxides (La1−xSrxCoO3), in regard to the effects of Sr2+-substitution and calcination temperature. The reducibility and the readiness of oxygen desorption increased with the Sr2+…
The Raman spectra of YFe${\mathrm{O}}_{3}$, SmFe${\mathrm{O}}_{3}$, DyFe${\mathrm{O}}_{3}$, HoFe${\mathrm{O}}_{3}$, and ErFe${\mathrm{O}}_{3}$ have been measured as a function of temperature from 8 to 650 K. For all the materials, the spectra show two features in the 5 to 20 ${\mathrm{cm}}^{\ensuremath{-}1}$ range. Fr…
The article begins with an account of prewar German work, particularly that of von Ardenne, who established the theoretical basis of a scanning electron microscope and constructed an instrument which was primarily intended to overcome chromatic aberration when relatively thick specimens were examined by transmission.…
Examination of the three-dimensional structure of periphyton communities through time indicated that their microsuccession is analogous to higher plant succession. The development of attached diatom communities in two reservoirs was studied using artificial substrates, and the morphology of dominant organisms, pattern…
The fluorescence of molecules on silver-island films exhibits nonexponential decay and is several orders of magnitude more rapid than on a silica surface, while the total emission intensity is slightly increased. This behavior results from the electromagnetic coupling between the fluorescing molecules and the plasmon…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCalcium carbonate crystallization kineticsLarry D. Swinney, John D. Stevens, and Robert W. PetersCite this: Ind. Eng. Chem. Fundamen. 1982, 21, 1, 31–36Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published inissue 1 February 1982htt…
The multiple-trapping model is used in order to analyse the propagation and broadening of a carrier packet. The traps are considered to be distributed over rather a wide energy region in the gap. We assume that at the initial moment traps are empty and all the carriers occupy mobile states. Under these conditions the…
Several peptides containing intermolecular crosslinks were isolated from tryptic digests of the insoluble matrix of human leiomyoma and calf aorta. From leiomyoma type III collagen, two crosslinked peptides were isolated. The peptide [T N (III)] 2 , is a dimer which contains the 73 amino‐terminal residues of two, zero…
Abstract The effect of initiation of ϵ‐caprolactone polymerization with mono‐ and polyfunctional alcohols was investigated. The resulting linear and starshaped polymers were characterized by measurement of the molecular weight and molecular weight distribution. The polymerizations were characterized by (1) rapid initi…
Abstract Nonstoichiometry and point defect structure of magnetite have been studied experimentally by thermogravimetry covering the stability range of magnetite between 900 and 1400 °C. A cation deficit is observed at high and a cation excess at low oxygen activities corresponding to cation vacancies and iron intersti…