Materials Literature
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Estimations are made of the critical concentration of energy-acceptor ions for which the average efficiency of the excitation transfer from energy-donor ions is 1/2. This gives a measure of the activator concentration at which Inokuti and Hirayama's theory is no longer applicable. Study is also made of the dominant mu…
The optical constants nx, kx, nz, and kz of the uniaxial compound GaSe have been determined in the energy region 2–5 eV (wavelength region 240–700 nm) using ellipsometric measurements on a plane perdendicular to the optic axis (the cleavage plane) and a plane parallel to this axis.
Abstract A mineral with a 10Å X‐ray spacing is the dominant clay mineral in the surface horizon of many dryland soils in which vermiculite or vermiculite‐biotite is dominant in subjacent horizons. The mineral occurs in soils with aridic, torric, xeric, and ustic moisture regimes. To study its genesis we separated weat…
DC conductivity measurements were carried out on low-density polyethylene films of thickness 25, 50 and 75 μm. The material showed non-ohmic conduction on application of high electric fields in the range 1 × 10 7 to 3 × 10 7 Vm −1 . The results were applied to a model proposed by Adachi et al (1971) and good agreement…
A measurement is presented of the anisotropic liquid-structure factor of $p\ensuremath{-}n$-octyloxybenzylidene-${p}^{\ensuremath{'}}$-toluidine in the nematic phase using monochromatic Cu $K\ensuremath{\alpha}$ radiation. This material has a smectic $A$ phase at lower temperature and exhibits strong pretransition sca…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAzodicarboxylic acid esters as dealkylating agentsEdward E. Smissman and Alexandros MakriyannisCite this: J. Org. Chem. 1973, 38, 9, 1652–1657Publication Date (Print):May 1, 1973Publication History Published online1 May 2002Published inissue 1 May 1973https://pubs.acs.org/do…
Abstract Unter den Metallchelaten des Phthalocyanins (Me‐Pc), des polymeren Phthalocyanins und des Tetraazaannulens (Me‐TAA) mit Me = H, Fe, Co, Ni und Cu befinden sich Vertreter hoher Aktivitä bezüglich einer Elektrokatalyse der Sauerstoffreduktion. Aus voltammetrischen Messungen an den in 85‐96% Schwefelsäure gelöst…
Abstract Needle‐like crystals of polyoxymethylene, 5 to 20 μm long, have been obtained in the course of the polymerisation of trioxane in cyclohexane. It has been found that such crystal growth is favoured at large BF 3 .OEt 2 /H 2 O or BF 3 /H 2 O ratios, when the nucleation takes place fast. The needle is considered…
Denaturation temperature of pepsin-treated collagen from calf skin was measured Viscometrically in neutral pH solution by adding glucose which completely depresses collagen fibril formation without denaturing collagen molecules. The stability of collagen molecules in solution thus obtained was greater at neutralpH tha…
As a part of the research program on the behavior of polluted insulators, the mechanism of flashover due to contamination has been analysed in a recent publication [1].
Two sets of skinfold measurements were made on 21 subjects by three observers using a Harpenden caliper. One of the observers had several years’ experience of the technique, while the other two were relatively inexperienced. Measurements were made at the biceps, triceps, subscapular and suprailiac sites. In one set o…
The factors influencing the digestion of pebble-milled cellulose by enzymes were studied by using several strains of Ruminococcus albus including a mutant characterized by a more eccentric location of its colony in the clearing produced by digestion of the cellulose in the thin layer lining the wall of a culture tube.…
Abstract Recycling of waste plastics as a blend of generic types is attractive since a difficult separations problem is avoided. However, blends of incompatible polymers are frequently very brittle and cannot be considered for many applications. Additives which modify the blend to give it ductility may provide a solut…
The influence of conducting particles on the ac breakdown of compressed SF6has been investigated for two coaxial systems having inner electrodes of diameter 75 mm and 150 mm and a 250 mm diameter outer electrode, using voltages up to 450 kV rms at pressures up to 1.8 MNm-2(18 atm.). For filamentary particles of 0.1 mm…
Light-scattering spectra of the soft-optic and -acoustic modes of K${\mathrm{D}}_{2}$P${\mathrm{O}}_{4}$ have been studied in the 0-0.8-${\mathrm{cm}}^{\ensuremath{-}1}$ spectral region for temperatures from 0 to 10\ifmmode^\circ\else\textdegree\fi{}K above the ferroelectric phase transition. The true spectra of the s…
Probenherstellung, Diffusionsglühen und Analyse der Proben mit der Mikrosonde. Gemeinsamer Diffusionskoeffizient als Funktion der Kohlenstoffaktivität. Vergleich mit Selbstdiffusionsmessungen.
Erbium hexaboride was synthesized; it is a high‐temperature phase, stable over a limited temperature range and unstable with respect to dissociation to ErB 4 and ErB 12 at T <1975°C, although the lower temperature limit has not been determined precisely. Relatively slow cooling through its stable temperature range…
Variation of the magnetic spectra with the amount of cobalt ions is measured for samples (35- x )NiO · 8ZnO · x CoO · 57Fe 2 O 3 ( x =0∼2.5) in the frequency range from 2.5 to 1200MHz. It is shown that the dominant mechanism of the static initial-permeability of the slowly cooled samples changes with the amount of cob…
Crystal quality during zone refining is usually poor. Owing to the great density of high-diffusivity paths, solid-state diffusion should not be neglected. Its influence on the concentration profile is described by experiment and theory. Since the concentration gradient and curvature become very large at the end of the…
While chemical analyses of deposits from archaeological sites have often used phosphorus as an indicator of past human activity, there is little agreement on which type of phosphorus test is most useful for particular problem orientations. This paper evaluates the utility of tests for total phorphorus, available phosp…