Materials Literature
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We present results of ab initio band structure calculations on some ABO 2 delafossite oxides that have both the A and B sites occupied by transition metals. This class of materials includes insulators as well as some of the most conducting oxides. The calculations have been performed in order to understand the nature…
A characterization has been carried out on the dihydrate and anhydrous crystalline form of trehalose (α- d -Glucopyranosyl-α- d -glucopyranoside), which is considered anomalous in respect to other disaccharides in conferring to organisms the ability to be dried at high temperatures and then to rehydrate without damagi…
Poly(diallyldimethylammonium) chloride ( P ) and sodium decatungstate ( W ) were layer-by-layer self-assembled onto quartz, mica, and ITO-electrode substrates (S). The self-assembled films, S-( P / W ) n, were characterized by absorption spectrophotometry, reflectivity, cyclic voltammetry and scanning force microscopy…
Three pentaatomic molecules CSi 2 Al 2, CSi 2 Ga 2, and CGe 2 Al 2 were studied at the B3LYP/6-311+G* and MP2/6-311+G* levels of theory (with tests also run at multiconfigurational levels) to determine whether the central carbon atom exists in a planar geometry. We found that cis -CSi 2 Al 2 and trans -CSi 2 Al 2 plan…
50/50 wt % blends of isotactic polypropene (i-PP) with metallocene-based random poly(ethene- co -1-butene) (PEB) were prepared with 1-butene content varied from 52 to 100 wt %. The melt miscibility of the i-PP/PEB blends as a function of 1-butene content was studied by investigating the morphologies of the blends in t…
The microstructure of cold-crystallized poly(ether−ether−ketone)/poly(ether−imide) (PEEK/PEI) blends has been investigated by a combination of wide- and small- angle X-ray scattering (SAXS), dielectric spectroscopy, and transmission electron microscopy. Both SAXS and dielectric spectroscopy indicate that most PEI is e…
Two new compounds containing tellurite building blocks coordinated to copper and barium atoms have been isolated from hydrothermal solvents. A new layered compound, Ba(2)Cu(4)Te(4)O(11)Cl(4) (I), has been obtained by reacting BaCl(2).2H(2)O, CuO, and Te(OH)(6) in NH(4)Cl solution at 375 degrees C for 4 days. Green, pl…
The tilings of rhombi in two dimensions and of rhomboedra in three dimensions are studied when they are constrained by fixed boundary conditions. We establish a link between those conditions and free or periodic boundary ones: the entropy is written as a functional integral which is treated via a saddle-point method.…
Digital x-ray imaging techniques of today require electronic detectors that can be applied to all modalities of medical imaging. This paper presents work showing that selenium, when used as a direct converter, can be competitive with present day scintillator technologies targeting mammographic, radiographic and fluoro…
The evolution of cross-linked polymer chain clusters in a solvent from a monomer solution has been investigated by dynamic light scattering. The characteristic decay time distribution, P (Γ -1 ), of the gelling system has been examined as a function of the initial monomer concentration, C, where Γ -1 and Γ are the cha…
The templating organoammonium cations of as-synthesized MCM-41 mesoporous silicas are ion-exchanged with [Co(en)3]3+or trans-[Co(en)2Cl2]+ in DMSO or ethanol neutral solutions, respectively. Pure electrostatic adsorption or complex grafting takes place at the inner MCM-41 surface depending on the nature of the complex…
A series of carbosilane dendrimer generations, G x RF6 ( x = 1−3) with perfluorohexyl (−C 6 F 13 ) groups on the surface and one dendrimer G3 without these end groups, have been studied using X-ray scattering and quasielastic neutron scattering. The G x RF6 form generation dependent superstructures as a result of the…
The accurate control of a system that exhibits hysteresis requires a control strategy that incorporates some form of compensation for the hysteresis. One approach is to develop an accurate model P of the hysteresis and then use the inverse P<SUP>-1</SUP> as a compensator (inverse compensation). This paper focuses on t…
The photoluminescence behavior of dicyanoargentate(I) ions doped in KCl host crystals has been studied. Several ultraviolet and visible emission bands are observed in this system. Each emission band becomes dominant at a characteristic excitation wavelength; that is, the energy of the emission can be tuned by site-sel…
Novel Ru(II) and Ru(III) complexes having TPA (tris(2-pyridylmethyl)amine, L1) and 5-Me(3)-TPA (tris(5-methyl-2-pyridylmethyl)amine, L2) were prepared to establish their synthetic routes and to elucidate coordination geometry and interactions between tightly bound tripodal tetradentate ligands and Ru(II)/Ru(III) cente…
The secondary relaxations of a series of glassy copolymers based on poly(ethylene terephthalate) (PET) and poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) involve cooperative motions of the cyclohexylene rings. The cooperativity gives rise to longer range motions which create significant volume fluctuations tha…
We present numerical simulations of avalanches and critical phenomena associated with hysteresis loops, modeled using the zero-temperature random-field Ising model. We study the transition between smooth hysteresis loops and loops with a sharp jump in the magnetization, as the disorder in our model is decreased. In a…
The thermal properties of silver are calculated within the quasi-harmonic approximation, by using phonon dispersions from density-functional perturbation theory, and the pseudopotential plane-wave method. The resulting free energy provides predictions for the temperature dependence of various quantities such as the eq…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationDirect Observation of Size-Dependent Optical Enhancement in Single Metal NanoparticlesSteven R. Emory, William E. Haskins, and Shuming NieView Author Information Department of Chemistry, Indiana University Bloomington, Indiana 47405 Cite this: J. Am. Chem. Soc. 1998, 120,…
Titania, zirconia, and alumina samples with periodic three-dimensional arrays of macropores were synthesized from the corresponding metal alkoxides, using latex spheres as templates. In a fast, single-step reaction, the monomeric alkoxide precursors permeate the array of bulk polystyrene spheres and condense in air at…