Materials Literature
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Principal component analysis (PCA) was performed on the correlation matrix of 16 characters measured on each of 129 specimens of the freshwater centric diatom Stephanodiscus niagarae from 14 lentic North American habitats. There were two major independent components to overall silicification. Firstly, larger valves we…
The measured electrical conductivity of ${(\mathrm{AgI})}_{x}{(\mathrm{Ag}\mathrm{P}{\mathrm{O}}_{3})}_{1\ensuremath{-}x}$ glasses for $0<x<0.6$ follows a power-law characteristic of site percolation. The percolation threshold is 0.3, the critical exponent 3.3, the vulnerability 4.8, and the number of contact si…
Abstract External standard and internal standard calibrations are important procedures for achieving high accuracy in X-ray powder diffraction studies. The theoretical basis as well as procedures for obtaining calibration curves are given. Methods and examples of selecting Standard Reference Materials (SRMs) which are…
Sepia cartilage collagen (pepsin-extracted) in acetate buffer (pH = 2.98) forms micelles at a particular concentration below which they do not normally form. The critical micelle concentration (cmc) of the collagen was determined in buffer as well as in SDS, cetyltrimethylammonium bromide (CTAB) and Tween-80 micellar…
A comparison of several fracture toughness determination methods based upon the use of cracks emanating from a Vickers hardness indent to the bulk techniques of double cantilever beam and single edge notch beam is made in a tough zirconia material which shows little evidence of transformation toughening based on the a…
Three molecular combinations, each consisting of two disk-shaped (tripheny-lene units) and one rod-shaped mesogen (azobenzene- and azobophenyl-units) were synthesized with the aim of generating new liquid crystal phases. Two molecular geometries were realized thereby. The trimesogen 1 with laterally fixed rod-like mes…
Nanotechnology is concerned with manufacturing to dimensions or tolerances in the range 0.1-100 nm. It plays a key role in many areas including materials processing, mechanical engineering, optics and electronics. Technologies for manipulating materials at or near the molecular level are coming increasingly into use.
It is difficult to delineate Cyclotella, Cyclostephanos and Stephanodiscus—the three most taxonomically diverse, predominantly freshwater genera of the Thalassiosiraceae. Cyclostephanos was originally distinguished by a Stephanodiscus-like exterior of fasciculate striae and raised radiating costae, and a Cyclotella-li…
The active form of aconitase has a diamagnetic [4Fe-4S]2+ cluster. A specific iron ion (Fea, which is lost during inactivation) is the binding site for substrate, as shown by Mössbauer spectroscopy. We have studied the mode of substrate and analogue binding at equilibrium to the paramagnetic [4Fe-4S]+ cluster of the r…
Fluctuations of corrosion potential have been analyzed for localized corrosion of Type 304 stainless steel immersed in solutions containing . Potential fluctuations were sampled by a microcomputer, and power spectra were calculated by the fast Fourier transform (FFT). Acoustic emission (AE) was also measured to invest…
Abstract Poly( L ‐lysine) was reacted with various azo‐reagents, including p ‐phenylazobenzoic acid, p ‐phenylazobenzoyl chloride, and p ‐phenylazobenzoic N ‐hydroxy‐succinimide ester, to give polypeptides containing 5–44 mol % azobenzene units in the side chains. The conformation of the azo‐modified polypeptides was…
Several freshwater naviculoid diatoms, for which Mereschkowsky erected the genus Placoneis, have been re-examined with light and electron microscopy. The findings reveal that, in addition to their distinctive chloroplast type, their valvar structure also differs significantly from that of Navicula sensu stricto, and t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDerivatized polyoxomolybdates. Synthesis and characterization of oxomolybdate clusters containing coordinatively bound diazenido units. Crystal and molecular structure of the octanuclear oxomolybdate (NHEt3)2(n-Bu4N)2[Mo8O20(NNPh)6] and comparison to the structures of the pa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation of activated carbon by thermal decomposition of used automotive tiresSadao Ogasawara, Mikiya Kuroda, and Noriaki WakaoCite this: Ind. Eng. Chem. Res. 1987, 26, 12, 2552–2556Publication Date (Print):December 1, 1987Publication History Published online1 May 2002Pub…
Domain splitting in the grains of ferroelectric ceramics reduces the internal elastic stresses which are caused by spontaneous deformation. Hysteresis switching reflects the increase or absence of internal stress. Small signal elastic and electric ac fields applied to the ceramic cause reversible domain wall motion th…
Nickel oxide ( NiO ) cathode solubility in the molten carbonate fuel cell (MCFC) electrolyte has been identified as one of the major technical obstacles facing fuel cell commercialization. The solubility of transition metal oxides is thought to be a function of the acid/base chemistry of the melt, controlled by the CO…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIn situ photoreduced silver nitrate as a substrate for surface-enhanced Raman spectroscopyAngela M. Ahern and Robin L. GarrellCite this: Anal. Chem. 1987, 59, 23, 2813–2816Publication Date (Print):December 1, 1987Publication History Published online1 May 2002Published inissu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBimetallic lanthanide complexes of the calixarenes: europium(III) and tert-butylcalix[8]areneBrenda M. Furphy, Jack M. Harrowfield, David L. Kepert, Brian W. Skelton, Allan H. White, and Faye R. WilnerCite this: Inorg. Chem. 1987, 26, 25, 4231–4236Publication Date (Print):De…
After briefly summarizing the most common reactions used in the chemical synthesis of polyoxyphenylenes, this paper reviews the electrochemical polymerization of phenols for metal protection. It also describes how the reaction media, sometimes in unexpected ways, influence the chemical composition of the coatings and…
A new method for the acid hydrolysis of protein is presented. Peptide bonds are cleaved by the action of an HCl/trifluoroacetic acid (TFA) vapor mixture. Contamination for the hydrolysis mixture is reduced to low levels (1-3 pmol). Recovery of hydrophobic amino acid is improved. Short reaction times are achieved and r…