Materials Literature
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The thermal conductivities, λ, of single‐crystal and polycrystalline UO 2 were measured from 80° to 420°K. The results indicate no observable difference in λ between single‐crystal and polycrystalline UO 2 , and both materials have broad peaks in λ at ∼220°K. The results were used with literature values to determine t…
The thermal decomposition of lithium oxalate has been studied by means of weight loss and measurement of surface area. It has been found possible to correlate changes in surface area with the kinetics of decomposition.The reaction studied was the decomposition of the oxalate to the carbonate which occurs with an incre…
The thermal decomposition of KMnO4 in the temperature range 25–900° in air and nitrogen has been studied by thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction, and chemical analysis. The idealised decomposition equation (250°, air) was found to be 10 KMnO4→ 2·65 K2MnO4+(2·35 K2O,7…
Pentaco-ordinate complexes of the type M(pnp)X2 or M(pnp)XY are described; M = FeII, CoII, or NiII; X = Cl, Br, or I; Y = NCS; pnp is the new ligand 2,6-bis-(2-diphenylphosphinoethyl)pyridine. Distorted trigonalbipyramidal structures are assigned on the basis of physical properties. Magnetic susceptibility measurement…
Abstract Depending on temperature and load rate an unoriented polymer solid under sufficiently large applied stress either deforms plastically (high temperature, low rate of loading) or undergoes brittle fracture (low temperature, high rate of loading). The fracture proceeds through the areas of minimum strength, i.e.…
A moderate surface reduction of TiO2(anatase or rutile) at 573–773 K under vacuum, or in the presence of carbon monoxide or hydrogen, or finally at room temperature under ultra-violet irradiation in vacuum or in the presence of hydrocarbons, creates two types of paramagnetic centres, which are identified by e.s.r. spe…
In order to cOlltrol the cast structllre, it is most im/Jortallt to kllow lite Jorlllatiol!mechanism and the behavior oj eqlliaxed crystals ill tlte 1II0ltell metal durillg the solidification .The solidification jJhenomellol!was directly observed with (III o/Jtical microscojJe Jor the cases q! 99.999° oSn, Sn -O.l, 0.…
Arago nit e (C aCO ,,) c ry s ta lli zes in th e unit ce ll a = 4.9598(5) /\ . 6 = 7.9641(9) A, and c = 5.7379(6) A at 25 C with four form ula we ight s in s pace-g roup Pm cn. Th e s tru cture has bee n re fin ed to N".= 0.024 . N = 0.040 using 765 x-ray re Aec tion s fro m a sin gJe c rysta l. Th e Ca ion is coo rdi…
The results of two new experiments designed to determine the contact angle of water on ice are reported. In one it is shown that the first stage of melting of a clean ice surface is liquid formation at discrete sites, not uniformly over the surface as would be predicted if the contact angle were zero. The water has a…
The small nephelauxetic parameters dβ for lanthanide heteropolytungstate complexes show that the Ln–O bond is essentially ionic. The absorption spectra of the EuIII complexes indicate, in each case, site symmetry not higher than tetragonal for the lanthanide; the emission spectra of EuW10O357– and Eu(SiW11O39)211– in…
The anodic dissolution of tungsten was studied in solutions and solutions at 25°C. Faradaic efficiency studies in basic solutions showed the metal to be oxidized to the +6 state. In acid solutions, a thick protective film of yellow was formed. Polarization curves possessed linear Tafel regions at potentials slightly m…
The discovery is reported of the first optically active smectic liquid crystal to consist of only one compound and to permit supercooling to room temperature. The compound is bis-(p-6-methyloctyloxybenzylidene)-2-chloro-1, 4-phenylenediamine.
The thermal decomposition of diborane-phosphine mixtures in a hydrogen atmosphere and the thermal reduction of boron tribromide-phosphorus trichloride mixtures with hydrogen have been used for the deposition of boron phosphide on the basal plane of hexagonal silicon carbide substrates. In the thermal decomposition pro…
A theory is developed of the circular dichroism and rotatory power of thin films of cholesteric liquid crystals. It is an extension of the treatment for infinitely thick specimens discussed in a previous paper. The therory predicts that the circular dichroism of a thin film plotted as a function of wave-length should…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared studies of adsorption and surface reactions of some secondary alcohols, C3 to C5, on .gamma.-alumina and .gamma.-alumina doped with sodium hydroxideA. V. Deo, Tze-Tang Chuang, and I. G. Dalla LanaCite this: J. Phys. Chem. 1971, 75, 2, 234–239Publication Date (Print)…
Difficulty is found in fitting experimental g values for low-spin ferric haemoproteins to formulae based on a pure t 2 5 configuration. This is discussed and it is shown that it is almost certainly mainly due to neglect of configuration interaction with excited t 2 4 e states, a mechanism which was originally discusse…
The double refraction of 32 liquid crystalline substances and their dependence on temperature and wavelength has been studied. The measurements were made on uniaxially oriented liquid crystalline layers using the principle of Abbé's double prism. Such optically uniaxial layers are obtained from the nematic states and…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhosphorescence microwave multiple resonance studies in determining the radiative and nonradiative properties of the triplet stateMostafa A. El-SayedCite this: Acc. Chem. Res. 1971, 4, 1, 23–31Publication Date (Print):January 1, 1971Publication History Published online1 May…
A method is proposed for the determination of phosphorus in plant material using a modified Kjeldahl digestion and a Technicon Autoanalyzer. The procedure depends upon the formation of phosphomolybdate and its reduction to molybdenum blue by ferrous ammonium sulphate. The method enables the simultaneous determination…
A method is described which enables the direct measurement of relaxation times and relaxed and nonrelaxed heat capacities as a function of temperature. The apparatus designed is to be used as additional equipment to the Perkin-Elmer differential scanning calorimeter DSC-1B. The specimen is heated periodically with tim…