Materials Literature
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Abstract The weathering of biotite in soils formed in saprolites derived from granite and gneiss was studied. The soils occurred in the Southwestern Upland of Nigeria which is characterized by a humid tropical climate. Vermiculite and montmorillonite are the usual products of biotite weathering in well‐drained tempera…
A combination of Knudsen effusion and mass spectrometric techniques has been employed in studying the gaseous species in thermodynamic equilibrium with condensed CeO2 and with condensed Ce–CeO2 mixtures. A thermodynamic treatment of ion currents yields a value of ΔH°298=135±6 kcal mole−1 for the heat of vaporization o…
The energy analyzer described is of the spherical mirror-spherical grid retarding potential type. It obtains high resolution through a small energy overlap between low energy pass and high energy pass filter functions. The first filter is a spherical electron mirror operating slightly off-axis in a reflection mode. Th…
A biaxial split Hopkinson bar which operates in simultaneous compression and torsion is described. The device utilizes torsional stress waves generated by release of a stored torque and compressive waves generated by mechanical impact of a long rod onto a loading bar. The torque is released by capacitive discharge exp…
The objectives are to examine the variation of these properties with organic content and to compare the behavior of mechanical mixtures with that of natural samples of comparable organic content. The effect of mineralogy is also studied to check its possible influence on mechanical behavior and on the organic content…
Abstract The effect of the addition of certain low molecular weight compounds to highly crosslinked epoxy resins was investigated. The behavior which is known as antiplasticization, such as increases in modulus and yield strength and the elimination of β‐transition, was observed in the highly crosslinked system as wel…
Abstract The crystal structure of Ca 3 (VO 4 ) 2 is rhombohedral with space group R 3 c and unit-cell parameters a = 14.124(1) Å and α = 44.96(2)°, with equivalent hexagonal axis lengths of a = 10.809(1) and c = 38.028(9) Å. The rhombohedral cell contains seven formula units. The structure was refined by full-matrix l…
The current-voltage characteristics in off state and the switching phenomena are investigated. The results can be well explained by a thermal model based on the self joule heating of the sample. The results are summarized as follows: (1) I - V characteristics in off state can be normalized over a wide range of tempera…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExternal standards in x-ray photoelectron spectroscopy. Comparison of gold, carbon, and molybdenum trioxideWilliam P. Dianis and Joseph E. LesterCite this: Anal. Chem. 1973, 45, 8, 1416–1420Publication Date (Print):July 1, 1973Publication History Published online1 May 2002Pu…
Abstract A theoretical determination of the elastic modulus, the breaking strength, and breaking strain is made for a single infinitely long molecule of polyethylene (CH 2 ) ∞ . These results are compared with those of a similar calculation on a molecule of polyethylene with a side chain attached. It is found that the…
Abstract It is shown that a strong contrast may arise in dark‐field electron microscope images between two crystal parts related by an inversion operation, as a result of the violation of Friedel's law. Friedel's law is violated only in the diffracted beam and only in cases where a multiple‐beam situation prevails. Mo…
SUMMARY The weak‐beam method of electron microscopy enables the high resolution capabilities of the electron microscope to be used in the study of lattice defects. In this paper, the principles of the method are outlined and the experimental procedures for obtaining weak‐beam images are discussed. The experimental dif…
Nuclear magnetic resonance measurements in the smectic liquid crystalline phases of seven thermotropic compounds are reported. The compounds investigated are: terephthalbis(butylaniline); ethyl(methoxybenzylidene)amino] cinnamate; diheptyloxyazoxybenzene; octyloxybenzoic acid; dipentylazoxycinnamate; diethylazoxycinna…
The use of benzotriazole as a corrosion inhibitor is briefly reviewed and the theory of its mode of protection for copper in aqueous conditions is considered. The solubility has been found to increase with temperature, and the addition of benzotriazole decreased the pH and increased the conductivity of distilled water…
Abstract Dynamic mechanical behavior during the reactions of four aromatic diamines ( m ‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenyl sulfone, and benzidine) with the diglycidyl ether of bisphenol A was studied by torsional braid analysis under isothermal conditions. Depending on the cure temper…
Abstract Alkaline hydrolysis of model carbamates, polyurethanes, and poly(urethane‐ureas) has been investigated. The model carbamates were based upon phenyl, benzyl, and cyclohexyl isocyanates. The polyurethanes and poly(urethane‐ureas) were prepared from tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), and 4…
Single crystals of NaCl, NaBr, KCl, and KBr containing divalent additions of Ca 2+ , Sr 2+ , and Ba 2+ were tested mechanically. In the solution‐treated condition, the yield strength, σ v , as determined from compression testing in a 〈100〉 direction is essentially dependent on the concentration of the dopant only and…
The complications of calculating the photoabsorption cross section of atoms for frequencies in the far ultraviolet and soft x-ray regions motivate an analysis of this problem on the basis of the Bloch semiclassical model of hydrodynamic charge oscillation in the neutral Thomas-Fermi atom. The hydrodynamic modes of osc…
Abstract Although hair form has received much attention in the past, it has rarely been studied systematically, and never using direct curling variables. In the present study, seven groups were scored on eight variables, including four newly‐devised curling variables. These data were analyzed using univariate and mult…
Most sulfosalts may be regarded as intermediate phases on joins between simple sulfide components (e.g., all lead sulfbismuthinides lie on the PbS-Bi2Sa join). Many of the structures are characterized by subunits whose individual structures are similar to those of the component simple sulfides (e.g., galena-like and s…