Materials Literature
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A simulated annealing method for atomic resolution structure prediction of alpha-helical coiled coil proteins is described which draws upon knowledge of the oligomerization state, the helix directionality, and the properties of heptad repeat sequences. Unknown structural parameters, such as the coiled coil twist angle…
We consider both the spatial domain and spectral domain forms of the Green's function, appropriate in the electromagnetic diffraction of a plane wave incident at a general angle in the xy plane on a singly periodic structure, or grating, oriented along the x axis. We equate the spatial and spectral forms of the Green'…
A unifying, quantitative analytical framework has been developed for rhombohedral perovskite structures, ABO 3 . Three principal parameters are defined: polyhedral volume ratio, V A /V B , mean octahedral tilt angle, , and octahedral distortion, Δs. The first two of these parameters are directly related through the eq…
Although stable under hydrostatic pressures up to 20 GPa, ${\mathrm{C}}_{60}$ molecules transform to a transparent and insulating material if compressed nonhydrostatically at room temperature. On the other hand, quasihydrostatic loading at higher temperatures yields black, electrically conducting samples. We report he…
Abstract Hectorite and saponite are exchanged with [Al 13 O 4 (OH) 24 (H 2 O) 12 ] 7+ and the amount of Al 3+ adsorbed and Na + released are followed as a function of the exchange conditions. On saponite the reaction is a pure ion exchange with 2–2.15 mmol Al 3+ /g adsorbed and release of 0.80 mmol Na + /g. On hectori…
Unsymmetrically substituted (phthalocyaninato)nickel(II) complexes –7 were synthesized by statistical condensation of 4,5‐dipentoxy‐ ( 2a ), 4,5‐diheptyl‐ ( 2b ), 3,6‐dihexoxy‐ ( 2c ), and 3,6‐diheptylphthalonitrile ( 2d ) with 3,4,5,6‐tetraphenylphthalonitrile ( 1 ) and separated by column chromatography. The obtaine…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoordination Patterns for Biliverdin-Type Ligands. Helical and Linked Helical Units in Four-Coordinate Cobalt and Five-Coordinate Manganese(III) Complexes of OctaethylbilindioneAlan L. Balch, Marinella Mazzanti, Bruce C. Noll, and Marilyn M. OlmsteadCite this: J. Am. Chem. S…
Cyclotrimerization of 4,5‐bis(hexylthio)phthalodinitrile ( 1 ) in 1‐chloronaphthalene in the presence of BCl 3 leads to the subphthalocyanine 4 . Unsymmetrical phthalocyanines ( 5, 6 ) with six alkylthio substituents on three of the benzenoid units are synthesized by the reaction of 4 with an diiminoisoindoline deriva…
The surfaces of medical devices may promote both coagulation and infections caused by adherent microorganisms. In the case of polymeric elastomers, these iatrogenic effects are likely intermediated by absorbed host proteins that spontaneously bind to the device surface, promoting both bacterial adherence and thromboti…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Novel Protocol to Entrap Active Urease in a Tetraethoxysilane-Derived Sol-Gel Thin-Film ArchitectureUpvan Narang, Paras N. Prasad, Frank V. Bright, Arun Kumar, N. Deepak Kumar, B. D. Malhotra, M. N. Kamalasanan, and Subhas ChandraCite this: Chem. Mater. 1994, 6, 10, 1596–1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRNA Cleavage and Phosphate Diester Transesterification by Encapsulated Lanthanide Ions: Traversing the Lanthanide Series with Lanthanum(III), Europium(III), and Lutetium(III) Complexes of1,4,7,10-Tetrakis(2-hydroxyalkyl)-1,4,7,10-tetraazacyclododecaneK. O. Aileen Chin and Ja…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSterically Stabilized Colloidal Particles as Model Hard SpheresS. M. Underwood, J. R. Taylor, and W. van MegenCite this: Langmuir 1994, 10, 10, 3550–3554Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October 1994http…
The fracture behavior of PZT specimens driven at their resonant frequency by the application of an ac voltage was investigated and compared with fracture behavior of monotonically loaded PZT. Microcracking was observed in the cyclically loaded specimens; above 150°C, the micro‐cracks were dispersed in small clusters,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn Investigation of Framework Substitution of Cobalt into Aluminophosphate-5 Using Electron Spin Resonance and Temperature-Programmed Desorption MeasurementsVadim Kurshev, Larry Kevan, D. J. Parillo, C. Pereira, G. T. Kokotailo, and R. J. GorteCite this: J. Phys. Chem. 1994,…
The sample volume in diamond-anvil pressure cells suitable for X-ray powder diffraction studies is very small (</= 100 mum across). The resulting low signal-to-noise ratio has made it very difficult to obtain useful results with monochromatic angle-dispersive techniques, and the alternative white- beam energy-dispersi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBis(2,3-naphthalocyaninato)lutetium(III) and (2,3-Naphthalocyaninato)(phthalocyaninato)lutetium(III) Complexes: Synthesis, Spectroscopic Characterization, and ElectrochemistryFrancois Guyon, Annig Pondaven, Pierre Guenot, and Maurice L'HerCite this: Inorg. Chem. 1994, 33, 21…
This article investigates the structure of an Er luminescence center in GaAs by using its intra-4f-shell luminescence spectrum as an atomic probe to identify the atomic configuration. This Er center is formed in GaAs by metalorganic chemical vapor deposition with O codoping and the center shows a high efficiency and a…
Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution and have already been profoundly affected by the application of existing ML ...Read More
Abstract— Failure of ceramic materials occurs when the stress intensity factor of the most serious crack in a component reaches a critical value K I , C , the fracture toughness of the material. In case of ideal brittle materials the fracture toughness is independent of the crack extension and, consequently, identical…
Electroactive pH‐controlled membranes are a potential application of materials presented here. The functionalization of conjugated pyrroles with pendant carboxylic groups has been used to produce polymer electrodes exhibiting the electrochemically‐controlled release of protons. The synthesis and the electrochemical ch…