Materials Literature
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The isothermal oxidation behavior of commercial hot‐pressed Si 3 N 4 was evaluated for temperatures from 1300° to 1500°C. Multiphase scales were formed, consisting mainly of α‐cristobalite and enstatite. A large increase in reaction rate above 1450°C is believed to be caused by melting in the scale and the consequent…
The intracellular pH (pHi) of giant barnacle muscle fibers was measured with glass microelectrodes and also calculated from the distribution of 5,5-dimethyl-2,4-oxazolidinedione (DMO) and methylamine (MA). Simultaneously applying any two of these methods to muscle fibers of the same barnacle, we found the pH measured…
Abstract Previous work has shown evidence that PMMA and PEMA are miscible with PVF 2 . The present paper examines in detail the behavior of PEMA/PVF 2 blends by thermal analysis and dynamic mechanical testing. All transitions and relaxations are affected by blond composition but in a complex manner owing to the crysta…
Abstract The synthesis and structure of the p ‐hydroxybenzoic acid polymer is described. The polymer was successfully prepared from either the phenyl ester of p ‐hydroxybenzoic acid or from p ‐acetoxybenzoic acid. With highly purified acetoxybenzoic acid, single crystals of the polymer could be prepared. The structure…
Abstract The density of states of the transition‐metal layer compound 2H‐NbSe 2 , is calculated for both valence and conduction bands. The solid is studied by means of two different oneelectron models, one where the sandwiches of the structure interact with each other and one where instead each sandwich is treated as…
Summary Seven samples of pelletat glauconites with varying iron and potassium contents were investigated using the electron microprobe. In-sample variation of pelletal compositions is quite important, even for samples previously separated according to grain-size, density, and magnetic susceptibility. This observation…
Abstract In blends of elastomers and thermoplastics one component may be regarded as reinforcing the other. Examples are enhancement of tensile strength, tear strength, abrasion resistance, and modulus of elastomers by thermoplastics and improvement of impact resistance and environmental stress-cracking resistance of…
The steady state heat flow problem in the atator cores of large turbine-generators is solved using three-dimensional finite elements. The results are compared with those obtained by a thermal resistive network procedure and with factory test data. Three-dimensional plots of core iron isotherms are shown which describe…
Vanadium-base alloys, V—10% Cr, V—20% Ti, and VANSTAR-7, alloys with potential for fusion reactor application, have been irradiated in the Experimental Breeder Reactor II in the temperature range of 400 to 800°C, mainly to a fluence of 1.5 × 1022 n/cm2 (>0.1 MeV). Swelling determined both from immersion density measur…
Recent progress in the understanding of the improper ferroelectric phase transitions is reviewed. The phase transition in ammonium Rochelle salt is discussed from the symmetry point of view. The phase transitions in some improper ferroelectrics, such as langbeinite, boracite and dicalcium strontium propionate, are dis…
Synopsis Some relevant physical characteristics of akwara and akwara-reinforced concrete (akwaracrete) are discussed. Akwara is a natural vegetable stem fibre, dark brown in colour when mature, and has a hard smooth sheath enclosing a cellular core. Akwara is brittle and lighter than water. It is dimensionally stable…
The incoherent illumination moiré phenomenon between a periodic and a quasiperiodic structure is examined by the use of the spatial frequency analysis of the resultant transmittance. This approach has an advantage in that it completely explains all the fringe parameters without considering the averaging effect of the…
Hydrogen interaction with oxygen in copper exerts a significant influence on the apparent hydrogen diffusivity and the quantity of hydrogen absorbed. This interaction associated with steam embrittlement has been well established in alloys with high oxygen contents, such as electrolytic tough pitch (ETP) copper. Howeve…
The application for surface sensitive analytic techniques to the study of grain boundary diffusion in thin films is described. Two common experimental configurations, sputter profiling and permeation analysis, are described, as are solutions for data reduction. Analytic solutions are difficult to use, even with simpli…
A priori estimates of the suitability of a particular crystal for charge density analysis are discussed in terms of a simple criterion based on core electron concentration and a more detailed evaluation of the anticipated errors in the final deformation density maps. Predictions are compared with the results obtained…
Measurements of dipole relaxation of two types of ${R}^{3+}$-interstitial complexes in $\mathrm{Sr}{\mathrm{F}}_{2}:{R}^{3+}$ single crystals using the ionic-thermocurrents method are reported. For the light elements in the series of lanthanides we have found relaxations due to tetragonal complexes, whereas in crystal…
ATP citrate lyase was purified by two different procedures from the livers of rats first starved and then fed with a fat-deficient and high carbohydrate-glycerol diet. These enzyme preparations were judged homogeneous by sedimentation equilibrium and polyacrylamide gel electrophoresis. The molecular weight of the nati…
We have measured the optical Kerr constant and the orientational relaxation times of seven $p$,${p}^{\ensuremath{'}}\ensuremath{-}\mathrm{di}\ensuremath{-}n\ensuremath{-}\mathrm{alkoxyazoxybenzene}$ homologous compounds as functions of temperature in the isotropic phase. The observed critical behaviors near the isotro…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of new isomeric water-soluble porphyrins. Tetra(2-N-methylpyridyl)porphine and tetra(3-N-methylpyridyl)porphinePeter. Hambright, Tomiko. Gore, and Marilyn. BurtonCite this: Inorg. Chem. 1976, 15, 9, 2314–2315Publication Date (Print):September 1…
We have measured the second order β and third order γ hyperpolarizabilities of the PBLG polypeptide α-helix and find it to have an extremely large nonlinearity. The decay time of the generated harmonic has been directly determined and found to be τ=5.0 msec which is consistent with Kerr and dielectric experiments. The…