Materials Literature
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The fine structure of Bombyx mori silk fibroin was investigated by electron microscopy and X-ray diffraction techniques. Examination of silk fibers fragmented with ultrasonic radiation and negatively stained revealed the presence of ribbon-like filaments of well-defined lateral dimensions. Analysis of the breadths of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of Metal Hydrides. I. Reactions of Some Platinum(II) HydridesH. C. Clark and W. S. TsangCite this: J. Am. Chem. Soc. 1967, 89, 3, 529–533Publication Date (Print):February 1, 1967Publication History Published online1 May 2002Published inissue 1 February 1967https://…
It has been observed that in polycrystalline cadmium regions of linear hardening insensitive to temperature and strain rate occur at temperatures below 150 °K. The extent of this region increases as the temperature decreases. The hardening coefficients of single crystals are also independent of temperature below 150 °…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemistry of coordination compounds. XVI. Hexabromoplatinate(IV) and hexaiodoplatinate(IV) ionsVincenzo Balzani, Maria F. Manfrin, and Luca MoggiCite this: Inorg. Chem. 1967, 6, 2, 354–358Publication Date (Print):February 1, 1967Publication History Published online1 May…
Au-SiO2 thin-film cermets have been deposited by simultaneously dc sputtering Au and rf sputtering SiO2. The electrical resistivity varies exponentially with Au concentration, and the microstructure shows discontinuous networks of Au and SiO2.
Recent observations relating to the critical resolved shear stress for slip in tantalum and tungsten are reported. The results of tensile and compressive deformation are discussed in terms of the operative slip systems and the possible asymmetry of {112} [Formula: see text] slip. It is concluded that the asymmetry hyp…
Abstract The combined use of electron microscopy and of selected area diffraction (SAD) has been applied to the study of montmorillonites from Wyoming and from Camp-Berteaux, of nontronite, and of hectorite. The study shows that only the elementary layers of the Wyoming montmorillonite and of the nontronite are single…
The effect of electron traps on the current-voltage (J-V) relationship and the charge distribution in insulators, under conditions of space-charge-limited current flow, is well understood. This paper extends the consideration of trapping effects into the region of emission-limited current flow. Trapped space charge di…
The theory of the Portevin—Le Chatelier effect is extended to include the effect of dislocation multiplication. The dislocation density ρ in Cu-3.2 at. % Sn is measured as a function of true plastic strain ε by the transmission electron microscopy of thin films, and the relation ρ= 4.73 × 1011 ε1.17 established. The e…
The steady-state flow stress, σ, of commercial purity aluminium was determined by extrusion over a range of temperatures, T, from 255–616 °C, and strain rates, [Formula: see text], between 0.1–10 sec −1 . The data are shown to fit the relationship[Formula: see text]where A, α, and n′ are constants. The activation ener…
1. The diatom, Hantzschia virgata, appears on the surface sands of Barnstable Harbor, Mass., during daytime low tides. Surface accumulations of this organism reach such concentrations that the sand takes on a golden-brown color. As the tide returns the cells re-burrow into the sand. 2. The cells can be prevented from…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structures of the red, yellow, and orange forms of mercuric iodideGeorge A. Jeffrey and Marcus VlasseCite this: Inorg. Chem. 1967, 6, 2, 396–399Publication Date (Print):February 1, 1967Publication History Published online1 May 2002Published inissue 1 February 1967htt…
Current theories of work hardening in stage II of stress–strain curves of f.c.c. crystals are reviewed critically. A detailed account is given of a theory described previously in outline by Hirsch (1964).
Abstract In the part installment of the present paper, the authors formulated the dynamics of melt spinning by introducing a set of fundamental equations that consist of the equations of heat, force, and material balances. Some steady‐state solutions were also given. Additional steady‐state solutions corresponding to…
Chloramphenicol-resistant strains of Escherichia coli which carry the episomal resistance transfer factor R inactivate the antibiotic by enzymatic acetylation. In the presence of chloramphenicol and acetyl coenzyme A, cell extracts catalyze the formation of both a monoacetyl and a diacetyl derivative of chloramphenico…
Polycrystalline specimens of α-phase copper–aluminium alloys of varying composition, amalgamated with mercury, have been deformed in tension in a soft tensile machine. In all cases, brittle intergranular failure occurred at stresses and strains below those required for fracture in air, the degree of embrittlement incr…
When excited by the proper wavelength, Tb+3 in Y2O3 transfers some of that energy to Eu+3 centers which subsequently emit 6125-Å light. The actual mechanism involves an initial high-energy excitation state (a broad band, indicating a perturbed activator state) which relaxes to one of the 5DJ states, from which emissio…
The approximate corona-starting relation for concentric cylinders Ec/δ = A + B/√rδ, long established at lower gas densities, has been checked in air to δ = 35 over the respective ranges of inner and outer cylinder diameters of 0.0178 to 0.635 cm and 4.72 to 15.40 cm (Ec = corona-starting field at surface of inner elec…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of Metal Hydrides. II. Spectroscopic Studies of Fluorovinylplatinum(II) DerivativesH. C. Clark and W. S. TsangCite this: J. Am. Chem. Soc. 1967, 89, 3, 533–539Publication Date (Print):February 1, 1967Publication History Published online1 May 2002Published inissue 1…
The thermal expansions of TiB 2 , ZrB 2 , HfB 2 , NbB 2 , and TaB 2 were measured to temperatures above 1600°C by an X‐ray method. Lattice constants were measured for each compound; each had the AlB 2 ‐type hexagonal structure. The mean linear thermal expansion coefficients were calculated from the data and are compar…