Materials Literature
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We present a two-sublattice Ising-type model, involving one intramolecular interaction treated rigorously and intermolecular interactions treated in the mean-field approach, in order to describe the two-step transition exhibited by a bi-nuclear spin-crossover complex. Spontaneous symmetry breakings can be obtained acc…
The powder neutron diffraction pattern of pyrolusite, ß-MnO2 [P42/mnm, No. 136, a = 4.4041(1), c = 2.8765(1)?], has been refined by the Rietveld method to give values for both the oxygen position parameter u=0.3046(1) and the anisotropic thermal parameters. The data confirm the MnO6 octahedra to be elongated with two…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, characterization, and crystal structure of the gadolinium(III) chelate of (1R,4R,7R)-.alpha.,.alpha.',.alpha.''-trimethyl-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3MA)Sang I. Kang, Rama S. Ranganathan, John E. Emswiler, Krishan Kumar, Jack Z. Gougout…
Electrical conductivity of calcium‐doped lanthanum chromites, , was determined as a function of composition, temperature, and oxygen partial pressure, , to determine its defect structure and understand its redox behavior. The conductivity was independent of and was proportional to the dopant concentration at high . Th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical electron transfer in chlorophyll-porphyrin-quinone triads: the role of the porphyrin-bridging moleculeDouglas G. Johnson, Mark P. Niemczyk, David W. Minsek, Gary P. Wiederrecht, Walter A. Svec, George L. Gaines III, and Michael R. WasielewskiCite this: J. Am. C…
The surface of untreated wool has been investigated using x-ray photoelectron spec troscopy (XPS) and static secondary ion mass spectrometry (SSIMS). The wool surface is covered in a thin layer of lipid estimated to be approximately 0.9 nm thick. Mass spectral peaks are consistent with the presence in the lipid layer…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEquilibrium surface orientation of lamellaeG. T. Pickett, T. A. Witten, and S. R. NagelCite this: Macromolecules 1993, 26, 12, 3194–3199Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June 1993https://pubs.acs.org/doi/10…
Ceramic/ceramic composites in the Ti‐B‐C system were fabricated by a novel process referred to as transient plastic phase processing (TPPP). The basic concept is based on the following reaction: “soft” transient plastic matrix + reactant phase → hard matrix + reinforcement phase where the transient plastic phase is a…
Relationships between diatom assemblages and physiocochemical factors were examined in 63 saline lakes in western North America. Sodium was the overwhelmingly dominant cation in the lakes examined; lakes above 47° latitude were dominated by SO 4 — 2 , and lakes below 47° were dominated by CO 3 — 2 and Cl — 1 . This la…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn unusually weak intervalence transition in a very stable bis chelate analog of the ruthenium mixed-valent Creutz-Taube ion. UV/visible/near-IR and EPR spectroelectrochemistry of [(NH3)4Ru(.mu.-bptz)Ru(NH3)4]n+ (bptz = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine; n = 3 - 5)Juergen…
A critical problem in the study by Komori and Makishima about the microstructural characterization of general fiber assemblies is analyzed, and a modified approach is presented in this paper. The modified theory is able to predict satisfactorily such , parameters as the mean values of the number of fiber contacts and…
A comparative study of tetragonal (Y-TZP, 3 mol% Y 2 O 3 ) and cubic (CSZ, 15 mol% CaO) zirconia powder samples was carried out to learn about a possible structural origin of the superior ionic conductivity of TZP at low temperatures. Structure refinements including anharmonic temperature factors and oxygen occupancie…
Abstract Unter den Nichtmetallnitriden sind vor allem die polymer aufgebauten binären Verbindungen BN und Si 3 N 4 für die Entwicklung von Werkstoffen für Hochleistungsanwendungen von Interesse. Herausragende Merkmale beider Substanzen sind ihre thermische, mechanische und chemische Beständigkeit bei gleichzeitig geri…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface-enhanced Raman scattering (SERS) for semiconductor microcrystallites observed in silver-cadmium sulfide hybrid particlesI. Honma, T. Sano, and H. KomiyamaCite this: J. Phys. Chem. 1993, 97, 25, 6692–6695Publication Date (Print):June 1, 1993Publication History Publish…
Abstract The conversion of smectite to illite has been studied in buried bentonites and shales of the East Slovak Neogene Basin, using X-ray diffraction analysis and transmission electron microscopy. A good correlation was observed in both rock types between the content of expandable layers in interstratified illite-s…
Abstract Dried samples of polyacrylamide in an He atmosphere have been subjected to thermogravimetric analysis in the 30–600°C range, and the evolved gases were monitored by FTIR. Water, ammonia, and small quantities of carbon dioxide are released in the first stages of decomposition (220–340°C), where the polymer cha…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of poly(aniline-co-o-anisidine). A processable conducting copolymerS. S. Pandey, S. Annapoorni, and B. D. MalhotraCite this: Macromolecules 1993, 26, 12, 3190–3193Publication Date (Print):June 1, 1993Publication History Published online1 May 20…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular weight dependence and end-group effects on the surface tension of poly(dimethylsiloxane)Claire Jalbert, Jeffrey T. Koberstein, Iskender Yilgor, Paula Gallagher, and Val KrukonisCite this: Macromolecules 1993, 26, 12, 3069–3074Publication Date (Print):June 1, 1993Pu…
A broad tuning range is demonstrated in tunable DBR lasers with a novel superstructure grating (SSG). These SSG reflectors were fabricated by electron-beam lithography, and grating performance was evaluated by measuring the transmittance characteristics of a ridge-type SSG reflector. Incorporating this SSG reflector i…
Incoherent-inelastic-neutron-scattering studies were carried out on polyisobutylene, presumably the least-fragile polymeric glass former known so far. A fast dynamical process on a frequency scale of roughly 500 GHz is measured for temperatures higher than the glass transition essentially without being influenced by t…