Materials Literature
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Symmetry, dimensionality, and disorder play a pivotal role in critical phenomena. The atomic imaging capabilities of the scanning tunneling microscope were used to directly visualize the interaction between charge density oscillations and lattice defects in a two-dimensional charge density wave (CDW) system. Point def…
The Pt/TiO 2, Pt/ZrO 2, and Pt/Al 2 O 3 catalysts submitted to low-temperature reduction (LTR, 200 °C) and high-temperature reduction (HTR, 500 °C) and exposed to hydrogen and carbon monoxide at room temperature were studied by infrared spectroscopy. There is a strong loss of transmission in the entire infrared spectr…
The double-perovskite oxides Ca 2 FeMoO 6 , Sr 2 FeMoO 6 and Ba 2 FeMoO 6 show evidence of ferromagnetic metallic behaviour, with Curie temperatures of 345-426 K and saturation magnetization of 3.5-3.9 µ B /formula unit. Ceramics show little anisotropic magnetoresistance, but the low-field isotropic negative magnetore…
We present a brief analysis of the crossover phase diagram for the decay of a metastable phase in a simple dynamic lattice-gas model of a two-phase system. We illustrate the nucleation-theoretical analysis with dynamic Monte Carlo simulations of a kinetic Ising lattice gas on square and cubic lattices. We predict seve…
The dynamical mean-field theory together with the non-crossing approximation is used to set up a novel scheme to study the electronic structure of strongly correlated electron systems. The non-interacting band structure is obtained from a density functional calculation within the local density approximation. With this…
The receding contact angles of water drops on PMMA and PET surfaces were determined by using video microscopy to follow the time-dependent evaporation of sessile drops. Depending on the initial drop size, receding angles of θ r = 54−64° for PMMA and θ r = 64−66° for PET were found with an average hysteresis of 23.5 ±…
Crystalline nanofibers of linear polyethylene with an ultrahigh molecular weight (6,200,000) and a diameter of 30 to 50 nanometers were formed by the polymerization of ethylene with mesoporous silica fiber-supported titanocene, with methylalumoxane as a cocatalyst. Small-angle x-ray scattering analysis indicated that…
The kinetic model of the ethyl benzene oxidation was applied to the design of the large-scale reactors of p -nitroacetophenone (chloramphenicol key intermediate) synthesis by p -nitroethyl benzene oxidation and benzoic acid synthesis by acetophenone oxidation. The factors allowing simplification of the above model are…
Solid-phase synthesis of triple-helical peptides, including native collagen III sequences, was started with a trimeric branch, based upon the lysine dipeptide [Fields, C. G., Mickelson, D. J., Drake, S. L., McCarthy, J. B., and Fields, G. B. (1993) J. Biol. Chem. 268, 14153-14160]. Branch synthesis was modified, using…
We present a new method for highly spatio-resolved graft-copolymerized surface fabrication, in which the stem design (parent graft chain length) and the branch design (daughter graft chain length and degree of branching) are relatively well controlled. This is based on the photochemistry of the benzyl N,N -diethyldith…
Magnesium phthalocyanine (MgPc) is a blue pigment whose X-phase is known to exhibit an intense near-IR-absorption. Because of this, MgPc has attracted attention as a material useful for laser printers as well as optical disks based on GaAsAl laser diodes. The near-IR absorption has, therefore, been investigated from t…
Annealing of poly(ethylene- co -octene)s with 12−25 mass % 1-octene for 2.5−5250 min was carried out by approaching the annealing temperature through cooling at 10 K min -1 . Above the annealing temperature, primary crystallization was initiated. The analysis of the samples was performed during and after the annealing…
We study ballistic conductance in a three-terminal carbon nanotube system and show that conductance between two of the terminals can be controlled via the third terminal. The conductance is modulated by tuning the energy spectrum of the third terminal. Such a system may provide the core of a nanotransistor. We show mo…
Different samples of filled poly(vinyl chloride) (PVC) compositions were formulated from PVC, a polar plasticizer mixture consisting of dioctylphthalate (DOP) and a chlorinated paraffin, and variable proportions of a white filler such as barite, calcium carbonate, kaoline, quartz, or talc; a conductive filler such as…
New amorphous MnV 2 O 6+ δ · n H 2 O (0 < δ < 1) compounds have been prepared by a soft chemistry route including the precipitation of a crystallized precursor, MnV 2 O 6 ·4H 2 O, and its ozonation at temperatures below 100 °C. A combination of techniques (TGA, magnetic measurements, IR, XANES, EXAFS, XPS, and EELS) w…
The important properties of cellulosic fibers in the conditioned state are mainly influenced by fine structure. In particular, the development of new methods of spinning regenerated cellulosic fibers made from a cellulose/N-methylmorpholine-N-oxide (NMMO)/H2O system require a better understanding of their fine structu…
The reactions of I(2) with ptc and ttb (title ligands) have been investigated in CHCl(3) solution at different temperatures by spectrophotometry. A least-squares method procedure provided evidence for the formation of the 1:1 adducts. Crystals of the latter have been analyzed by X-ray diffraction methods (both monocli…
Dispersion copolymerization of styrene and a poly( N -isopropylacrylamide) macromonomer in ethanol−water media has been successfully carried out in the presence of AgNO 3 . Nearly monodisperse polystyrene microspheres with diameters ranging from 530 to 1250 nm were obtained. Nanoscopic silver particles were generated…
Three unsymmetrical tridentate pyridine-2,6-dicarboxamide binding units have been connected to the tris(2-( N -methyl)aminoethyl)amine tripod to give the podand L 10 that exists as a statistical mixture of four conformers in solution. In aqueous acidic medium, the protonated apical nitrogen atom of the tripod (p K a (…
The migration behaviors of wax to the surface in rubber vulcanizates were studied using natural (NR), styrene–butadiene (SBR), and butadiene rubber (BR) vulcanizates. The migration experiments were performed in a convection oven at 60 and 80°C for 14 days. There were less than 10% of the normal alkanes of n-C22H46 to…