Die bedeutung der calciumsulfatformen bei der abbindezeitregelung des zementes
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Contribution à la mesure de la granulométrie des constituants céramiques
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Über die rolle der feinstanteile im portlandzement
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Some Properties of Hafnium Oxide, Hafnium Silicate, Calcium Hafnate, and Hafnium Carbide
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.,…
Indirect Exchange Coupling of Nuclear Magnetic Moments by Conduction Electrons
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…
The oxidation of iron at 175 to 350° C
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.…
Variation of unit-cell dimensions of a crystal form of long normal chain carboxylic acids
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…
The crystal structure of silk fibroin
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…
The crystal structure of formamide
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 of a Nickel Zinc Ferrite
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 ${\mathrm{Ni}}^{++}$…
The magnetic anisotropy of cobalt
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…
The Binary Systems NaPO3-KPO3 and K4P2O7-KPO3
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…
X-ray determination of crystallinity in deformed natural rubber
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 Germanium and Silicon at Low Temperatures
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…
Thermal Conductivity: XI, Conductivity bf Some Refractory Carbides and Nitrides
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…
Infrared Evidence for Collagen Structures
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Industrial Diamond Substitutes: I, Physical and X‐Ray Study of Hafnium Carbide
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…
O3-MONOACETYLMORPHINE
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…
Sensitivity--a criterion for the comparison of methods of test
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…
The Use of Iodine Adsorption as a Measure of Cellulose Fiber Crystallinity
Cotton Cellulose 1, 2, 3, 4 Buthanetetracarboxylic Acid (BTCA) Crosslinking Monitored by some Physical—chemical Methods