Materials Literature
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Results are presented for the initial‐stage sintering of spinel in air at 1050° to 1300°C. Spinel powders of high purity were prepared from magnesium‐aluminum hydroxide coprecipitates by calcining at 1100°C for 4 h. The sintering mechanism is volume diffusion, and the temperature dependence of the apparent diffusion c…
The microstructure of the shell of bivalve molluscs was examined by lightand electron-microscopy. The purpose of this paper is to classify and describe this structure, and to discuss the affinity and evolutionary development among different kinds of shells. Shell structure consists of two elements, namely, the morphol…
The results of a study of the role of organic compounds in the formation of carlxmate crystals in marine biological systems are reported. In an increasing concentration of certain organic compounds which complex calcium ions, the proportion of aragonite decreases and that of calcite increases. In increasing concentrat…
Abstract Lactic dehydrogenase X, an isozyme found thus far only in mature sperm of mammals and birds, has been purified to homogeneity from rat tissue. A molecular weight of 125,000 ± 4,000 was determined. In addition to its ability to catalyze the pyridine nucleotide-linked interconversion of pyruvate and lactate, th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of cesium tetrakis (hexaflouroacetylacetonato)europate and -americate. Isomorphism with the YttrateJohn Howard Burns and Merlin D. DanfordCite this: Inorg. Chem. 1969, 8, 8, 1780–1784Publication Date (Print):August 1, 1969Publication History Published onlin…
Abstract The acetyl coenzyme A-l-aspartate N-acetyltransferase activity of a previously reported preparation obtained from the supernatant phase of rat brain homogenates by ammonium sulfate fractionation was reinvestigated and substantiated. The enzyme activity was located in particles, probably microsomes, dispersed…
Abstract The general fourth-order potential constants, f, for hydrogen cyanide were determined by a least-squares analysis applied to the observed values of the vibrational energies and the rotational constants for six isotopic species, H12C14N, H13C14N, H12C15N, D12C14N, D13C14N, and D12C15N. The normal frequencies,…
The Young's and shear moduli of polycrystalline yttrium oxide, dysprosium oxide, holmium oxide, and erbium oxide were determined at room temperature as a function of volume fraction porosity using the sonic resonance technique. Linear relations empirically described the data for Y 2 O 3 , Hr 2 O 3 , and Er 2 O 3 . The…
The real refractive index n and power absorption coefficient alpha of high resistivity GaAs and CdTe have been directly measured at 300 K and 8 K in the wavelength region from 12.5 micro to 300 micro. This spectral region contains the fundamental lattice resonance of both materials: 37.2 micro for GaAs and 71.4 micro…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProperties of formaldehyde-treated nucleohistoneDouglas Brutlag, Cameron Schlehuber, and James BonnerCite this: Biochemistry 1969, 8, 8, 3214–3218Publication Date (Print):August 1, 1969Publication History Published online1 May 2002Published inissue 1 August 1969https://pubs.…
Abstract Surface-area studies were made on several homoionic vermiculites with both nitrogen and carbon dioxide as adsorbates. These studies show that only very slight penetration occurs between individual vermiculite platelets. This is in contrast to an earlier investigation of montmorillonite where it was found that…
Abstract Thin films of polyethylene prepared from blends of fractionated polymer and a linear hydrocarbon ( n ‐C 32 H 66 ) have been used to study the role of intercrystalline links in the deformation of semicrystalline polymer under uniaxial stress. These links have been found to be strong and virtually inextensible…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of the low-spin iron porphyrin, bis(imidazole)-.alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinatoiron(III) chlorideRachel P. Countryman, Douglas MacPherson Collins, and James L. HoardCite this: J. Am. Chem. Soc. 1969, 91, 18, 5166–5167Publication Date (Prin…
It is well established that at temperatures above ∼0·3 T m the Cottrell theory relating the critical strain for serrated yielding, ε0, to temperature and strain rate becomes inapplicable. At these elevated temperatures ε0 increases with increasing temperature and decreasing strain rate. These phenomena may be rational…
It has been known that the transition temperature (Tc) of VO 2 is shifted by doping specified elements in VO 2 . In order to shift Tc in still wider range, experiments have been performed with adding various elements. As a result, it has become possible to shift the Tc of VO 2 either towards a higher temperature or to…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBiosynthesis of alkanes in Nostoc muscorumJerry Han, Henry W. S. Chan, and Melvin CalvinCite this: J. Am. Chem. Soc. 1969, 91, 18, 5156–5159Publication Date (Print):August 1, 1969Publication History Published online1 May 2002Published inissue 1 August 1969https://pubs.acs.or…
Absorption spectra at low temperatures are reported for AmCl3, AmBr3, and AmI3. Bathochromic shifts have been generally observed in the series from the chloride to the iodide. These shifts are comparable to those observed in lanthanide halides. Hypersensitive transitions have been observed in AmI3. A number of new ass…
Abstract A study has been made of the relationship between initial foam height, H, as measured by the Ross‐Miles test, and such factors as surfactant concentration, critical micelle concentration (CMC) of the solute, surface tension (γ) of the solution, surface area (A) of the foam, and the work involved in the produc…
The limit theorems of the generalized theory of perfect plasticity are applied to obtain bearing capacity in two dimensions (strip loading or rigid punch) and in three dimensions (circular and square punches). With the safe assumption that concrete or rock is unable to take any tension, the bearing capacity is shown t…
The dominant radiationles decay channel in crystalline tetracene at 300 °K is a fission of an excited singlet into two triplet excitons with a rate constant γS = 1.5 × 10−12 ± 5% cm3 -sec−1. The efficiency of this process at room temperature is estimated as 95%and constitutesan efficient intersystem crossing mechanism…