Materials Literature
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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…
The mechanical behavior of OFHC copper at strain rates from 10−3 to 103 sec−1 at 300°, 420°, and 590°K was investigated. The strain rate behavior of copper can be divided into two regions. Below 10 sec−1 the dislocation motion is thermally activated over forest dislocation barriers. Above 103 sec−1, a linear relations…
Abstract Electron microscopic textures of A–B type block copolymers of styrene and isoprene cast from several solvents were investigated by means of the osmium tetroxide fixation technique. The two‐phase structure, i.e., the semimicro heterogeneous structure due to the microphase separation of block segments, was obse…
Abstract X-ray analysis of Li + - and K + -saturated samples, differential thermal analysis (DTA), thermal gravimetric analysis (TGA), and chemical analysis of 83 samples enable a distinction to be made between Wyoming, Tatatilla, Otay, Chambers, and non-ideal types of montmorillonite, and between ideal and non-ideal…
Decalcification at the mantle-shell interface in Mercenaria tnercenaria was studied through the changes in the chemical composition of the extrapallial fluid, and by the measurement of Ca45-deposition and solution. Measurements of O2-tension demonstrated that the clam was anaerobic soon after the valves were closed. M…
Quasifree scattering of electrons on bound electrons gives direct information on the electronic wave functions in atoms and molecules, if the incoming energy is definitely higher than the electron binding energy. To tackle this new line of research the two outcoming electrons, whose energies are typically in the 0.1–1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTParamagnetic shifts in solutions of cholesterol and the dipyridine adduct of trisdipivalomethanatoeuropium(III). A shift reagentConrad C. HinckleyCite this: J. Am. Chem. Soc. 1969, 91, 18, 5160–5162Publication Date (Print):August 1, 1969Publication History Published online1…
The influence of intragranular bubbles, acting as efficient trapping sites, on the migration of fission gas atoms in material under irradiation is assessed. It is considered that the bubbles are unstable due to the operation of an irradiation-induced resolution process tending to dissolve their enclosed gas. Treating…
It is convenient to grasp crystals of a kind as “ferroelastic” crystals. They are defined analogously to “ferroelectric” crystals, mechanical strain and stress in the former corresponding to electric polarization and field in the latter respectively. The order of magnitude of the coercive stress for ferroelastic state…
A description is given of a fully automatic program, written in ALGOL 60, that finds the constants of the reciprocal lattice from powder data. The progress of the program is illustrated with the (nearly) complete computer output for one selected case. Planes through the origin of the reciprocal lattice (zones) are fou…
Abstract A method for measuring the surface energy of solids and for resolving the surface energy into contributions from dispersion and dipole‐hydrogen bonding forces has been developed. It is based on the measurement of contact angles with water and methylene iodide. Good agreement has been obtained with the more la…
Forty proteins with polypeptide chains of well characterized molecular weights have been studied by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate following the procedure of Shapiro, Vinuela, and Maizel (Biochem. Biophys. Res. Commun., 28, 815 (1967)). When the electrophoretic mobilities…
Abstract The mechanism of alternating copolymerization of propylene oxide with phthalic anhydride catalyzed by dialkylzinc is discussed. Dialkylzinc and phthalic anhydride form a complex which exhibits reactivity with propylene oxide to form alkylzinc alkoxide. Alkylzinc alkoxide thus formed reacts preferentially with…
The crystal-field splittings and hyperfine-structure constants of Eu 2+ in CaWO 4 have been accurately measured at 4.2 °K and at 78 °K using the method of electron paramagnetic resonance. These measurements were intended to provide liquid-helium temperature parameters for ENDOR experiments presently in progress but sh…
Au-Cd alloys in the range between 25 and 34 at. per cent Cd have been investigated by electron and X-ray diffraction as well as by calorimetry. The existence of a series of close packed structures with periodic stacking modulations and atomic order has been established. The order of appearance of the stacking variants…
The Raman spectra of the molten nitrates of lithium, sodium, and silver change as the temperature is raised. Close to the melting point well-developed low-frequency modes can be distinguished close to the exciting line while at higher temperature these have become somewhat broader but still quite distinct. There are a…
The oscillatory photoconductivity spectrum associated with the acceptor center in semiconducting diamond has been measured over the spectral energy range 0.35-2.6 eV (3.5-0.47 \ensuremath{\mu}). The energy separation between the acceptor ground state and the top of the valence band is more than twice the longitudinal…