Materials Literature
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Abstract The rational synthesis of the ‘cyclic’ tetranuclear p ‐cresol novolak ( VIII ) from the corresponding resole ( VII ) which was synthesized from 3‐bromo‐2:2′‐dihydroxy‐5:5′‐dimethyldiphenylmethane ( I ) has been accomplished in accordance with the scheme given below. A molecular model of the resole ( VII ) ind…
The yield and fracture stresses of unirradiated and irradiated End steel have been measured at 20°, −78°, and −196°c. From the change in yield stress, [sgrave], (shear), with grain size, 2d, the values of [sgrave] i and kv in a Petch type equation, [sgrave]v=[sgrave] i +kv d −1/2, have been determined. The term kv is…
Magnetic properties of synthesized solid solutions of ilmenite (MgTiO 3 , MnTiO 3 , FeTiO 3 , CoTiO 3 and NiTiO 3 ) and hematite (αFe 2 O 3 ) are investigated and it was confirmed that those of any ilmenite-hematite series can be divided into three parts: i) pure ilmenite, ii) solid solutions with R\bar3 crystal symme…
Abstract The bands due to stretching of OH groups in celluloses I, II and III I have been studied with plane polarized infrared radiation. The spectra show that all three crystalline modifications contain OH groups which make an angle much smaller than 55° with the chain direction, while other OH groups make angles gr…
New techniques are described which permit one to reverse the direction of the spontaneous polarization in liquid-electroded single crystals of BaTi${\mathrm{O}}_{3}$ with one growing domain which nucleates at a predetermined location on the crystal and then expands through sidewise 180\ifmmode^\circ\else\textdegree\fi…
Abstract The cracking of rubber by atmospheric ozone is now a well-known phenomenon and for a number of years rubber scientists and technologists have devoted considerable effort to combating it. While the differences of opinion and the confusion of data in this work are sometimes more conspicuous than the successes,…
Abstract The freezing point depression of polymer solutions was measured in the concentration range 5% to 30% (by volume of polymer), particular attention being paid to avoid excess supercooling. The polymer‐solvent combinations investigated were polystyrene‐benzene, polyvinyl acetate‐benzene, cellulose acetate‐acetic…
The technique of multiple factor analysis has been used to study the factors that affect the ‘handle’ of suiting materials. Unskilled observers describe the feel of these fabrics mostly in terms of smoothness, softness, coarseness, thickness, weight, warmth and stiffness. The relationship between these qualities and o…
An explanation based on kinetic considerations is developed for the failure of some pure liquids to crystallize. The important parameters are (1) α, the ratio of the molar liquid-solid surface tension to the heat of fusion ΔHf, (2) β, the ratio of the entropy of fusion to R, (3) ΔG′, the kinetic barrier to nucleation,…
The magnetic structure of ${\mathrm{Fe}}_{4}$N has been examined in a neutron diffraction study. The results are in agreement with a model proposed by Wiener and Berger on the basis of magnetic measurements on a series of related compounds. Ferromagnetically aligned moments of 3 ${\mathrm{\ensuremath{\mu}}}_{\mathit{B…
The nuclear magnetic resonance spectrum of B11 has been investigated in several glassy materials containing boron oxide. A value of 2.76±0.05 Mc for the nuclear quadrupole coupling constant of B11 has been calculated from the second-order quadrupole perturbation of the m = ½→—½ resonance line. The same quadrupole inte…
The Hall coefficient and magnetoresistance in purified (99.995%) natural graphite single crystals have been measured from 25 to 25 000 gauss at 298\ifmmode^\circ\else\textdegree\fi{}, 77\ifmmode^\circ\else\textdegree\fi{}, and 4.2\ifmmode^\circ\else\textdegree\fi{}K with the field oriented parallel to the hexagonal ax…
Static fatigue of a simple soda-lime glass has been investigated in relation to the sensitivity of this glass to atmospheric corrosion. An analysis of the failure process has been given which is based on the concept that inherent surface flaws grow by corrosive mechanisms to critical dimensions by virtue of a reaction…
The sublimation of hexagonal SiC has been studied under equilibrium conditions. The predominant gaseous species above SiC are Si, SiC2, and Si2C. By combining the heat of formation of gaseous Si from solid SiC and the known standard heat of formation of SiC, a value of 113 kcal/g atom is obtained for the heat of subli…
The important metallurgical problems relevant to circulating fuel reactors utilizing fused fluoride systems are discussed. The successful utilization of such mixtures is in large measure dependent upon the development of reactor materials which can both contain the mixtures under reactor conditions and afford usefuly…
A study of the magnetic properties of single crystal samples of nickel-iron ferrite with composition ${\mathrm{Fe}}_{1.00}^{3+}$[${\mathrm{Ni}}_{0.79}^{2+}$${\mathrm{Fe}}_{0.36}^{2+}$ ${\mathrm{Fe}}_{0.90}^{3+}$]${\mathrm{O}}_{4}$ has revealed an abrupt transition in the magnetic anisotropy characteristics at 10\ifmmo…
The phase transition in BaTi${\mathrm{O}}_{3}$ at the Curie point was investigated on single crystals with optical and electrical techniques. Besides raising the cubic-tetragonal transition about 15\ifmmode^\circ\else\textdegree\fi{}C in the usual way with an electric field along the cube-edge direction, an orthorhomb…
Large photoconductive effects have been observed on single crystals of ZnO at 300\ifmmode^\circ\else\textdegree\fi{}K and 78\ifmmode^\circ\else\textdegree\fi{}K. At 300\ifmmode^\circ\else\textdegree\fi{}K the decay of the photoconductivity is strongly dependent on the ambient conditions, being slow in vacuum and fast…
Iodine sorption and moisture sorption data and some density, x-ray, and infrared data have been obtained on partially acetylated (PA) cottons before and after progres sice deacetylation with 2 N hydrochloric acid or with N 2 sodium hydroxide. The re sults substantiate the accepted theory that in the partial acetylatio…
Measurements are reported of the thermal conductivity of glassy selenium and polycrystalline metallic (hexagonal) selenium at temperatures from 2\ifmmode^\circ\else\textdegree\fi{} to above 100\ifmmode^\circ\else\textdegree\fi{}K. At the higher temperatures, the heat conductivity, $\ensuremath{\lambda}$, for the glass…