Materials Literature
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F. Brailsford London: Van Nostrand. 1966. Pp. x + 274. Price £1 10s. The author's main aim has been to present an account of ferromagnetism with some mention of antiferro- and ferri magnetism. A chapter on dia- and paramagnetism is included for introductory purposes.
Abstract The materials formed by dialysis of the precipitates formed by the reaction of NaOH with mixed Mg-Al solutions are described. In addition to aluminium and magnesium hydroxides, two hydrocarbonates having Mg/Al ratios of about 5 : 1 and 2 : 1 are formed, essentially pure, from solutions with Mg/Mg + Al molar r…
The crystal structure of barium ferrite, BaFe12019,has been determined and refined with the use of three-dimensional counter data. The symmetry is P63/mmc; the unit cell whose dimensions are a = 5.893 Aand c = 23.194 A, contains two formula units. The structure is built up of ten close-packed (both cubic and hexagonal…
This paper describes the development of an instrument which is analogous to an electron microprobe x-ray analyzer, whereby the electron microprobe is replaced by an ion microprobe, and the x-ray spectrometer by a mass spectrometer. A duoplasmatron is the primary ion source. The primary ion beam is mass separated to el…
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Abstract Isotaktisches Polypropylen bildet bei der Kristallisation vier verschiedene Typen von Sphärolithen, die nach P ADDEN und K EITH als Typ I bis IV bezeichnet werden. Die Typen I und II zeigen eine monokline Kristallstruktur, während die Typen III und IV pseudohexagonal kristallisieren. Die Sphärolithe vom Typ I…
The decomposition of the methoxymethyl radical, generated in the mercury-photosensitized decomposition of dimethyl ether, has been investigated over the temperature range 200 to 300 °C and the pressure range 3 to 600 mm Hg. The radical decomposes to give a formaldehyde molecule and a methyl radical. The effects of pre…
The relationships between the third-order elastic constants of monocrystalline and polycrystalline (quasi-isotropic, randomly oriented) solids of cubic symmetry are derived according to elastic strain energy balances assuming negligibly small elastic strain energy contribution from mismatching of the grain boundaries.…
The complex dielectric constant of reduced rutile, $\mathrm{Ti}{\mathrm{O}}_{2\ensuremath{-}x}$, has been measured at frequencies between ${10}^{2}$ and ${10}^{5}$ Hz at temperatures between 1.2 and 50\ifmmode^\circ\else\textdegree\fi{}K. Three distinct relaxation processes have been observed: process I at temperature…
The isotope effect has been measured for self-diffusion in single crystals of zinc parallel and perpendicular to the $c$ axis at seven temperatures in the range 289-418\ifmmode^\circ\else\textdegree\fi{}C. A vacancy mechanism is found, with $\ensuremath{\Delta}K=0.93$, independent of temperature within the experimenta…
In lattices in which not all ions possess inversion symmetry, internal-strain effects give rise to piezoelectricity and contribute to the elastic response. It is possible to describe these internal strains as static optical-phonon-mode displacements and to analyze the internal-strain contributions to the elastic and p…
Piezoelectric Bi12GeO20 crystallizes in the cubic system with space group I23 and lattice constant a = 10.1455±0.0008 Å at 298°K. The complete x-ray scattering pattern within a reciprocal lattice hemisphere of radius (sinθ)/λ = 1.02 Å−1 was determined with PEXRAD. A total of 4812 reflections were measured, resulting i…
Linear thermal-expansion data are given for Ge, Si, GaAs, GaSb, InAs, and InSb at temperatures from 1.89\ifmmode^\circ\else\textdegree\fi{}K to approximately 40\ifmmode^\circ\else\textdegree\fi{}K. The data were obtained using a variable transformer as a sensor and are absolute in sample length changes. At the lowest…
The electrical resistivities and the Hall constants of the compound semiconductors GaSe, Mo${\mathrm{S}}_{2}$, Mo${\mathrm{Se}}_{2}$, and W${\mathrm{Se}}_{2}$, which crystallize in layer structures, have been measured at temperatures ranging from 100 to 700\ifmmode^\circ\else\textdegree\fi{}K. The Hall mobilities deri…
Abstract The distribution of aragonite in the skeletal parts of living organisms is reviewed, and its distribution in fossils is described on the basis of several hundred new determinations. Aragonitic fossils are extensively preserved in Tertiary sediments, and are common in Mesozoic rocks, particularly where the enc…