Materials Literature
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The behavior of hafnium oxide was studied particularly in the temperature range 1500° to 18OO°C. Properties of HfO 2 at these temperatures and its reactions with ZrO 2 , SiO 2 , and CaO are given in terms of lattice and other physical measurements, many of which are new. Mono‐clinic hafnium oxide is stable to 1700°C.,…
A calculation is given of the indirect exchange ${\mathrm{I}}_{i}\ifmmode\cdot\else\textperiodcentered\fi{}{\mathrm{I}}_{j}$ type coupling of nuclear magnetic moments in a metal by means of the hyperfine interaction with the conduction electrons. The interaction appears to account qualitatively for the broad nuclear s…
Abstract The oxidation of iron, previously freed from oxide by hydrogen treatment, has been studied at 175 to 350° C; five methods (gravimetric, electrometric, film -transfer followed by chemical or microscopic examination, X -rays and electron diffraction) have been used to identify and estimate the different oxides.…
The unit cells of form C of long normal chain carboxylic acids with 12, 14, 18, 22 and 26 carbon atoms are determined, using powder methods. All dimensions in the monoclinic cell are found to be dependent of the number of carbon atoms in the chain. The a and b axes and the angle fl decrease asymptotically with increas…
An X-ray investigation of a precipitate obtained by the action of pancreatic enzymes on an aqueous solution of silk fibroin suggests that the precipitate has essentially the same crystal structure as the silk fibre. Since the precipitate consists almost entirely of glycine, alanine and serine residues, it is concluded…
Formamide, I-ICONH~, melts at 2.5 C. On the basis of an X-ray diffraction investigation conducted at --50 C., it was found that the compound crystallizes in a monoclinic unit cell with: a ----3.690-01, b ----9.18+0.025, c ----6.870.02 /~, fl ----98% The space group is P21/n. There are four molecules per unit cell.
Neutron diffraction studies have been made of a ferrite powder of composition ${\mathrm{Zn}}_{0.5}$${\mathrm{Ni}}_{0.5}$${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$. The crystal structure is of the spinel type with 4 ${\mathrm{Zn}}^{++}$ and 4 ${\mathrm{Fe}}^{+++}$ ions in the tetrahedral positions and 4 ${\mathrm{Ni}}^{++}$…
Abstract A modified form of the magnetic balance previously designed by one of us, is described. In this apparatus the gradient is made independent of the magnetizing field. With such an apparatus measurements have been made on the variation of the intensity of magnetization with magnetic field for single-crystal spec…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Binary Systems NaPO3-KPO3 and K4P2O7-KPO3George W. MoreyCite this: J. Am. Chem. Soc. 1954, 76, 18, 4724–4726Publication Date (Print):September 1, 1954Publication History Published online1 May 2002Published inissue 1 September 1954https://pubs.acs.org/doi/10.1021/ja01647a…
A vulcanized natural rubber has been deformed in simple extension and in pure shear and the resulting diminution in X-ray intensity of the "amorphous" halo used as a measure of crystallinity. The effect of mode of deformation and attempts to reach "equilibrium" states by heat treatment at constant deformation are desc…
The thermal conductivity of a single crystal of Ge and a polycrystalline specimen of Si have been measured in the range 2 to 100°k. Both specimens were very pure. The results indicate that, at low temperatures at least, the lattice waves are not scattered by the conduction electrons, but that their mean free path is l…
The thermal conductivity of Tic, Sic, TiN, and ZrN has been measured in the temperature range 100° to 1000°C. The thermal conductivity of these materials decreases with increasing temperature. Determination of the Wiedemann‐ Franz ratio indicates that electronic conduction is considerable for TIC, TiN, and ZrN but is…
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A study of hard materials in an effort to find possible substitutes for industrial diamonds led to research on hafnium carbide. This compound was prepared from a mixture of hafnium dioxide and lampblack in a carbon resistance furnace by solid‐state reaction or from a melt. Some factors affecting the combined carbon co…
ADVERTISEMENT RETURN TO ISSUEArticleNEXTO3-MONOACETYLMORPHINELLEWELLYN H. WELSHCite this: J. Org. Chem. 1954, 19, 9, 1409–1415Publication Date (Print):September 1, 1954Publication History Published online1 May 2002Published inissue 1 September 1954https://pubs.acs.org/doi/10.1021/jo01374a001https://doi.org/10.1021/jo0…
In the evaillation of mall Y methods of test, t h e t \\'O usual cri tena-precision and aCCl!racy-are inwmcient.Accuracy is only applica ble wh ere compari sons with a standard can be made.Pr ec i ~ion, when interpreted as d egree of r ep roducibiltty, is ]Jot necessarily a measu r e of merit, becallse a me thod may b…
Cotton Cellulose 1, 2, 3, 4 Buthanetetracarboxylic Acid (BTCA) Crosslinking Monitored by some Physical—chemical Methods
X-ray measurements on NiOAl2O3, MnOAl2O3, and CoOAl2O3 show that the Ni spinel is almost completely inverted, the Mn partially so, and the Co compound almost completely normal. This information combined with the magnetic susceptibility vs temperature data yields a g-value of approximately 4.0 for both tetrahedrally co…
Es werden die Grundzüge einer Theorie der Kristallplastizität gegeben, die in wesentlichen Punkten von den bisherigen Theorien abweicht. Die kritische Schubspannung wird nicht, wie üblich, als kritische Länge von Frank-Read-Quellen, sondern als Wirkung der Spannungsfelder der im Kristall als Netzwerk vorhandenen Verse…
The temperature dependence of the minimum sound pressure needed to produce cavitation in gassy water has been measured over a range of 0 to 30°C. Both plane progressive and focused waves of frequency one megacycle per second were used. The cavitation pressure threshold Pc is not a linear function of temperature, and i…