Materials Literature
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Four new hydrocarbon tetraradicals, 1-4, each composed of two triplet trimethylenemethane (TMM) subunits linked \nby a potential ferromagnetic coupling unit (FC), were synthesized and characterized by variable-temperature electron paramagnetic resonance (EPR) spectroscopy. Simulation of the EPR powder spectra and…
Technology for rapidly determining cotton fiber length distributions using single fiber measurements has been developed jointly by USDA-ARS and Schaffner Tech nologies (now Zellweger Uster, Inc.). The instrument (AFIS) includes a mechanism for mechanically opening a hand-fed ribbon of fibers so that individual fibers…
The crystal structure of calmodulin (CaM; M(r) 16,700, 148 residues) from the ciliated protozoan Paramecium tetraurelia (PCaM) has been determined and refined using 1.8 A resolution area detector data. The crystals are triclinic, space group P1, a = 29.66, b = 53.79, c = 25.49 A, alpha = 92.84, beta = 97.02, and gamma…
The many-body empirical potentials that describe atomic interactions in the copper-bismuth system were constructed using both experimental data and physical quantities obtained by ab initio full-potential linear muffin-tin orbital calculations for a metastable ${\mathrm{Cu}}_{3}$Bi compound. These potentials were then…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMicrophase separation of block copolymer ringsJ. F. MarkoCite this: Macromolecules 1993, 26, 6, 1442–1444Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 1993https://pubs.acs.org/doi/10.1021/ma00058a038https://doi.…
Electrically conducting conjugated polymers such as polyaniline (PANi) usually show gel properties with volume changes in the range 1-100% in response to some external stimuli. The bending beam method provides an effective and sensitive way to detect and make use of these volume changes. Bipolymer laminate strips (2.5…
A computational model has been developed to calculate the potential and current distributions in the electrolyte phase and on the electrode surface for a system in which a part of the anode is passivated while the rest remains in the active dissolution state. The computation employs the finite element method allied wi…
A first principle mathematical model of the formation of calcareous deposits on a cathodically protected steel rotating disk electrode in seawater is presented. The model includes equations which transport phenomena, electrochemical reactions, precipitation reactions, and a homogeneous reaction involved in the formati…
Abstract By mixing Zntpp solid with o-chloranil, the rectification and photovoltaic properties of Al/porphyrin/Au sandwich-type cell are improved (Zntpp: 5, 10, 15, 20-tetraphenylporphyrinatozinc). The improvement may be mainly attributable to an increase in the hole concentration as the majority carrier because of th…
The sound velocities of the longitudinal and transverse vibrational modes in various directions have been measured by Brillouin scattering on high-quality twin-free single crystals of tetragonal PbTiO3. By using these velocities and the dielectric permittivity measured by the impedance method, a complete set of coeffi…
ABSTRACT: We consider stress relaxation in a strongly segregated lamellar mesophase, where block copolymers are in the “brush ” state with junction points confined to the interface between the adjacent lamellae and blocks stretched out away from it. If the molecular weight of the blocks is large enough, they entangle…
The valence of iridium in anodic iridium oxide films has been determined by x‐ray absorption spectroscopy and varies between 3.0 and 4.8 in a voltammogram cycle. When the valency starts to increase the first coordination shell around an iridium ion begins to shrink from 0.203 at to 0.191 nm at . At the same time a str…
The theory of the anomalous flow behaviour of Ll2 compounds has developed over the last 30 years. This theory has a foundation in the early estimates of the crystallographic anisotropy of antiphase-boundary (APB) energy in these compounds. In spite of this critical aspect of the theory, it is only in the last 5 years…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and characterization of (R)-poly(.beta.-hydroxybutyrate)-poly(.epsilon.-caprolactone) and (R)-poly(.beta.-hydroxybutyrate)-poly(lactide) degradable diblock copolymersMichael S. Reeve, Stephen P. McCarthy, and Richard A. GrossCite this: Macromolecules 1993, 26, 5,…
Chitosan is a novel biopolymer with numerous industrial, food, and biomedical applications. Our studies examined the production of chitosan from mycelia of Absidia coerulea, Mucor rouxii, Gongronella butieri, Phvcomyces blakesleeanus and Absidia blakesleeana. In batch culture, strains were screened to determine the fa…
In this study, we prepared a homologous series of dimeric compounds, di-BB-n These compounds have two mesogenic groups linked by a flexible methylene spacer and so can be regarded as model compounds for main chain liquid crystalline BB-n polyesters. In this dimeric system, we observed distinct odd-even effects in whic…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAqueous solution properties of ampholytic copolymers prepared in microemulsionsJean Marc Corpart and Francoise CandauCite this: Macromolecules 1993, 26, 6, 1333–1343Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March…
Introduction of nitrogen into zirconia creates oxygen vacancies in the anion sublattice as required by charge neutrality when N 3− replaces for O 2− in the structure, being similar to those obtained by lower valency cation substitution for zirconium. There is no essential structural difference between the cation‐relat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffects of chain pull-out on adhesion of elastomersHugh R. BrownCite this: Macromolecules 1993, 26, 7, 1666–1670Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 1993https://doi.org/10.1021/ma00059a027RIGHTS & PERMI…
Six Co-substituted magnetites ${\mathrm{Co}}_{\mathit{x}}$${\mathrm{Fe}}_{3\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{O}}_{4}$, with x\ensuremath{\le}0.04 have been studied by $^{57}\mathrm{Fe}$ M\"ossbauer spectroscopy at temperatures T between their respective Verwey transition and \ensuremath{\approxeq}900 K. The…