Materials Literature
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The vertical migration of two Euglena species and several diatom species into and out of the sediment on the banks of the River Avon has been studied under natural conditions. All species have been shown to migrate vertically upwards when exposed during daylight. Tidal flooding of the sediment is generally preceded by…
Voltage-current curves of such organic insulators as polyethylene-terephthalate and polyvinylformal display the familiar Richardson-Schottky characteristics for fields between 20 and 200 kV/cm and temperatures from 25° to 100°C. Assuming the Schottky emission mechanism being the limiting factor in establishing the ste…
A fracture theory is proposed for a composite system based on a continuous glass matrix. It is hypothesized that hard crystalline dispersions within the glass matrix will limit the size of Griffith flaws and strengthen the composite. Quantitative relations are derived for the effect of a dispersed phase on composite s…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSeparation of Gaseous Mixtures Using Porous Polyaromatic Polymer Beads.O. L. HollisCite this: Anal. Chem. 1966, 38, 2, 309–316Publication Date (Print):February 1, 1966Publication History Published online1 May 2002Published inissue 1 February 1966https://pubs.acs.org/doi/10.1…
A method is described for determining the optical constants of a thin film deposited on a nonabsorbing window using a single set of transmittances over an absorption band. The method depends on the fact that the phase shift of the transmitted radiation can be determined from the transmittances by a Kramers–Kronig tran…
Abstract Stress softening of carbon black‐reinforced butadiene‐styrene rubber was studied as a function of the rate and temperature of the original tensile deformation. To a good approximation, stress softening depends on the product of the extension rate and a temperature function which is analytically well represent…
<div class="htmlview paragraph">This paper describes full-scale engine studies conducted to determine the feasibility and compatability of ammonia combustion in various systems. Briefly outlined is the spark-ignition investigation undertaken by the Army Laboratory to learn the potential and effect of ammonia as…
Iron and aluminum were determined in acid ammonium oxalate extracts and in dithionite–citrate–bicarbonate extracts of a wide range of Canadian soils, several oxide and silicate minerals, and some amorphous preparations of iron or aluminum and silica. The oxalate extraction dissolved much of the iron and aluminum from…
The absorption and emission spectra of thallium in fused silica, aluminoborate, and phosphate glasses are similar to those of thallium-doped alkali halides and solutions. The absorption and emission bands in the different systems can be attributed to transitions within the central Tl+ ion in a center with a (TlXn)(n−1…
Investigation into the problem of melting within the earth strongly indicates that melting has taken place within the outer layers of the earth at some time in the earth's history. Fluid convection should then have occurred and have been an efficient method of heat transfer. Numerical methods are developed for calcula…
The magnetic properties of terbium oxide phases (Tb2O3 cubic and monoclinic polymorphs, TbO1.715, TbO1.809, TbO1.823, and TbO2) have been measured between 1.4° and 300°K. With the exception of TbO1.809, each of these phases is observed to order magnetically at low temperatures. The ordering is predominantly antiferrom…
Infrared spectra of metal-free phthalocyanine, chlorinated and unchlorinated copper phthalocyanines, and three new metal derivatives of phthalocyanine: MoPc, Na 2 Pc, and AlOH—Pc (Pc = C 32 H 16 N 8 ), have been recorded. Assignments have been suggested for many of the peaks in the infrared spectra of the phthalocyani…
The Kubo expression for lattice thermal conductivity is analyzed by the method of the double-time Green's function. The usual relaxation-time formula of kinetic theory can be obtained from the Kubo formula by suitable approximations only.
For the hopping motion of polaron holes the frequency factor ${W}_{0}$ of the transition probability is determined by the observation that hole localization occurs in a molecular orbital of the irreducible set ${t}_{2g}$ of a cation site group (with transfer integral ${b}_{\ensuremath{\pi}}$), whereas the superexchang…
The transmission and reflectance of cuprous oxide has been measured from 6 to 250 \ensuremath{\mu} and analyzed by classical dispersion theory. The two infrared-active vibrational frequencies are given by ${\ensuremath{\nu}}_{1}=613$ ${\mathrm{cm}}^{\ensuremath{-}1}$ and ${\ensuremath{\nu}}_{2}=146.0$ ${\mathrm{cm}}^{…
Emission of light by crystals mechanically deformed at room temperature after $\ensuremath{\gamma}$ irradiation at 35\ifmmode^\circ\else\textdegree\fi{}C has been studied. Spectra of several alkali halides were measured, and the intensity of the luminescence investigated in relation to $\ensuremath{\gamma}$ dose, stra…
The thermal conductivities of AlSb apd GaSb have been measured between 300 and 950\ifmmode^\circ\else\textdegree\fi{}K, and of GaP between 300 and 550\ifmmode^\circ\else\textdegree\fi{}K, on $n$-type samples of about ${10}^{18}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ using the diffusivity technique. The room temperature th…
X-ray studies of mica specimens from a variety of geological localities show that biotite and certain lithium-rich mica samples are composed of a mixture of different polytypes. Many of the biotite structures are new complex polytypes not before reported. A new method of designating mica polytypes is proposed. Techniq…
The superconducting transition temperature of stoichiometric ${\mathrm{La}}_{3}$${\mathrm{S}}_{4}$ has been measured by two different methods and has been found to be (8.25\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode^\circ\else\textdegree\fi{}K. A range of superconducting compositions exists in the metal-rich end of the $…
We report measurements of the spin-lattice relaxation rate ${{T}_{1}}^{\ensuremath{-}1}$ for several magnetically dilute rare-earth ions in the temperature range $1.2\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\leqq}T\ensuremath{\leqq}5\ifmmode^\circ\else\textdegree\fi{}$K, using the transient recovery of the micro…