Materials Literature
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The optical properties of benzene, pyridine, quinoline, and 2-ethylnaphthalene in the liquid state have been studied for photon energies from 2 to 10.6 eV. For each liquid the extinction coefficient k has been obtained from transmission measurements, and self-consistent values of the refractive index n calculated over…
Ultrasonication of Merino wool in formic acid liberates cuticle and then orthocortical cells. Further treatment produces a mixture of orthocortical and paracortical cells and finally a clean sample of paracortical cells is obtained.
Mössbauer and crystallographic investigations were carried out on DyFe3−x Nix compounds crystallizing in the PuNi3 type of structure. The hyperfine field observed at the iron sites shows a maximum at x =0.75. The 12-line spectrum observed at room temperature corresponding to the two different kinds of iron in the stru…
Abstract The resonance Raman spectra of cyano‐and aquocobalamin have been obtained from aqueous solutions. In order to check the vibronic theory of Raman intensity in the rigorous resonance case, the excitation profile of the 1502 cm −1 vibration was measured and analyzed using a model of two displaced harmonic oscill…
Abstract The thermal decomposition of silver(I) oxide and its reduction with reductive gases, such as ethylene, hydrogen, and carbon monoxide, have been studied by using a fixed-bed flow reactor. Under isothermal conditions, each reaction gave a sigmoidal shape to the fractional decomposition vs. time curves, and thes…
Auger electron spectroscopy was used to characterize grain‐boundary chemistry in MgO, Al 2 O 3 , and MgAl 2 O 4 (spinel) hot‐pressed with LiF or NaF. The presence of additives (F, Na) at the grain boundaries was confirmed; observation of grain‐boundary impurities in MgO extends previous studies.
CaC6HdO7 .3H20, prepared by slow precipitation from an aqueous mixture of calcium chloride and sodium citrate at a pH of 4.0, is monoclinic, P21/c, with Z = 4 , a=8.7955 (54), b=5.5891 (15), c=23.8176 (175) A, fl= 116.770 (57) °, F.W. 284.2, V= 1045.35 A 3, Dx = 1.806 g cm-3, Dm= 1.79 g cm -3; 2(graphite monochromatiz…
Abstract New series of diamines having pyridine rings and o ‐, m ‐, or p ‐phenylenedioxy linkages were prepared by condensation of chloronitropyridine with isomeric dihydroxybenzenes followed by chemical reduction. The polymerization of the diamines with benzo‐phenonetetracarboxylic acid dianhydride gave polyamic acid…
Abstract Aromatic benzimidazole polymers have been prepared by reaction of the corresponding tetraamine and diester in refluxing sulfolane or phenyl sulfone. The convenience of using these sulfone solvents together with the good yields, high viscosities and absence of crosslinking make this procedure an attractive new…
Abstract Creep tests at constant values of tensile stress, temperature, and relative humidity for two thermoplastics were conducted for approximately 132,000 hr. The strains, ϵ, for the first 2000 hr of time, t , were described by an equation of the form ϵ = ϵ o + ϵ + t n where all other symbols are constants. This eq…
A quantitative analysis of the effect of spin lattice relaxation rates on pure quadrupole resonance pulse experiments for spins with I = 1 is given. A model is presented in which the three dimensional relaxation problem is reduced to a two dimensional one. In this model any possible population distribution of the ener…
The effect of the magnetic transition on the optical-absorption edge has been studied for three antiferromagnetic crystals, MnO, $\ensuremath{\alpha}\ensuremath{-}\mathrm{MnS}$, and CoO. MnO shows a red shift, whereas $\ensuremath{\alpha}\ensuremath{-}\mathrm{MnS}$ and CoO show a blue shift. The observations can be sa…
Flat surfaces of MgO and KCl crystals and teflon sheet were coated with gold evaporated films except for the parallel strip areas approximately 200, 100 and 50 µm wide, and the strip areas without coating were observed by SEM at 15 kV. The images of the uncoated areas were distorted by the surface potential caused by…
Abstract When isotactic polystyrene (i‐PS) is crystallized from the melt or from the glassy state at rather large supercooling an additional melting peak appears on the curve during scanning in a differential calorimeter. The overall rate of crystallization deduced from the total peak areas as a function of crystalliz…
Abstract A new technique was developed to study the molecular mechanics of highly oriented polypropylene during stress relaxation and creep. The polarized infrared spectrum was recorded while the polymer was under load. Stress relaxation effects were investigated during the two‐stage process of fast decay followed by…
The theory of the holographic grating is applied to the design of aberration-corrected holographic concave gratings for use with Seya–Namioka monochromators. A method of determining the proper recording parameters is described. The performance of gratings that would be produced by use of the proper recording parameter…
The bulk magnetic susceptibilities of several synthetic polypeptides have been measured. The observed anisotropy of the diamagnetic susceptibility Δχ for oriented nematic liquid crystals of poly-γ-benzyl-L-glutamate (PBLG) in dichloromethane is 7.0±0.7×10−6 emu/mole. For a PBLG axial ratio of 150, a value of the twist…
Optical-reflection spectra have been measured for hexagonal NiS in the energy range 0.01 - 5.0 eV at temperatures both above and below the metal-nonmetal transition near 260 K. Using Kramers-Kronig analysis it is found that the conductivity below 0.1 eV drops on cooling through the transition. Above this energy a peak…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReversible reaction of simple ferrous porphyrins with molecular oxygen at low temperaturesDavid L. Anderson, Charles J. Weschler, and Fred BasoloCite this: J. Am. Chem. Soc. 1974, 96, 17, 5599–5600Publication Date (Print):August 1, 1974Publication History Published online1 M…
The design features of an efficient geometric backscattered electron detector are presented. This detector appears to have approximately the same limit of spatial detectability as a secondary electron detector. It has the advantages over a secondary electron detector of a reduction of charging artefacts, improved flat…