Materials Literature
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The interaction of NO with Cu{110} is complex and is strongly dependent on both coverage and temperature. When Cu{110} is exposed to NO in the temperature range 40−85 K, initial adsorption leads to the presence of molecular NO on the surface. With further exposure this is replaced by the dimeric (NO) 2 species and N 2…
A systematic PWM iron loss study has been carried out. All the loss components can be given as functions of the sum of pulses width in half a period. PWM loss surplus when compared with the sinusoidal supply is more pronounced in the laminations with more important part of dynamic loss in the whole loss outcome. Along…
The dielectric behavior of polybutadiene copolymers with different compositions of 1,2 and 1,4 units is analyzed to study the influence of the microstructure on the relaxation spectrum, especially the β relaxation. The experimental data were obtained between 10 -2 and 10 6 Hz and temperatures above and below T g . Abo…
Conditions for preparing copper–cerium mixed oxides by coprecipitation have been examined. X-Ray diffraction (XRD), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the oxides calcined at different temperatures up to 1073 K. In all cases, a solid solution is fo…
The kinetics of spiropyran photochromic systems in solution in a stirred batch reactor continuously irradiated with monochromatic light was studied by UV/visible spectrophotometry. The plots of absorbance vs time were analyzed, and the desired parameters (quantum yields, UV/visible spectrum of the unstable photomerocy…
Rapid water exchange and slow rotation are essential for high relaxivity MRI contrast agents. A variable-temperature and -pressure (17)O NMR study at 14.1, 9.4, and 1.4 T has been performed on the dimeric BO(DO3A)(2), 2,11-dihydroxy-4,9-dioxa-1,12-bis[1,4,7,10-tetraaza-4,7,10-tris(carboxymethyl)cyclododecyl]dodecane,…
The contribution of a redox mechanism involving lattice oxygen in the catalytic combustion of methane over PdO/ZrO 2 catalysts, prepared from amorphous Pd−Zr alloys, has been studied by means of gas pulse methods, including a novel technique “pulse thermal analysis”, and using labeled catalysts containing Pd 18 O. Spe…
The free-volume theory for solvent self-diffusion coefficients in polymer−solvent systems is modified to include a more general analysis of the effects of solvent size. The predictions of the theory are compared with self-diffusion data for a diverse set of solvents and four polymers, polystyrene, poly(vinyl acetate),…
A new class of natural antioxidants, chlorophyll a related chlorins 3, 4 (S), 4 (R), 5 (R), 6, 7, 8, and 9, have been synthesized from a chlorophyll a degradation product, pheophorbide a methyl ester ( 1 ). Claisen-type intramolecular condensation of pyropheophorbide a methyl ester ( 2 ) afforded the common intermedia…
A series of mixed-substituent poly(organophosphazenes) with the general structure {NP[OCH 2 CH 2 OCH 2 CH 2 OCH 3 ] x [O(CH 2 ) y CH 3 ] 2- x } n, where x = 1 and y = 2−9 was synthesized. These polymers are candidates for use as solid polymeric, ionic conduction media. The polymers were characterized by 1 H, 13 C, and…
Polymer gels swollen in a good solvent and subjected to a uniaxial deformation have been studied by small-angle neutron scattering (SANS). In all the experiments, the solvent is deuterated; this is equivalent to deuteration of the entire network. The gels were studied at two degrees of swelling, Q: Q = 11, which is ve…
Monte Carlo simulations were performed on star-burst dendrimer molecules having various numbers of spacer bonds P and various numbers of generations g . Each molecule is modeled by connecting freely-rotating rigid bonds in a star-burst architecture and by attaching to each end of the bond a hard-sphere bead of diamete…
Synthetic efforts utilizing Cs 2 CO 3, Ag, M 2 S 3 (M = As, Sb), and S 8 in supercritical ammonia (160 °C) have yielded four novel, one-dimensional compounds in the Cs−Ag−M−S system. These members were characterized by single-crystal X-ray diffraction and diffuse reflectance measurements. Cs 3 Ag 2 Sb 3 S 8 ( I ) crys…
The ductility of highly irradiated Zircaloy-4 material was evaluated by conducting tube burst, tube tensile, and ring tensile tests on fuel cladding and guide tubes irradiated in two PWRs. The specimen fluence ranged between 9 and 12.3 × 1021 n/cm2 (E > 1 MeV), and test temperatures ranged from 313 to 673 K. Th…
Mixed monolayers of a water-soluble tetracationic porphyrin (TMPyP) and an insoluble lipid matrix with anionic head groups (DMPA) were formed by the cospreading method. A ratio TMPyP:DMPA = 1:4 was selected by investigation of π−area isotherms and stability of the cospread monolayer. Reflection spectroscopy has been u…
Real-time in situ energy-dispersive X-ray diffraction has been used to study the synthesis of the open-framework sulfide TMA−SnS-1, under hydrothermal conditions. The effects of varying the temperature of reaction, reactant source, and pH of solution on the synthesis have been studied. It is found that temperature is…
Pole figures obtained by wide-angle X-ray diffraction have been used to quantify and characterize the molecular orientations induced in low-density poly(ethylene) films prepared by the tubular film process. Small-angle X-ray scattering was employed to determine the type and orientation of the morphology within the fil…
Ring-opening polymerization of ε-caprolactone catalyzed by rare earth halides and rare earth halide−epoxide has been carried out for the first time. It was found that rare earth halides have low activities for the polymerization of ε-caprolactone, but in the presence of epoxide, rare earth halides are highly active fo…
Hydroxoaluminium tricarboxymonoamidephthalocyanine has been adsorbed on TiO2(Degussa P-25) particles. Water suspensions and solid samples were analysed by SEM and by IR, visible extinction, diffuse reflectance and fluorescence spectroscopy. Visible spectra showed that the dye is not highly aggregated on the surface. F…
A dendritic system based upon a pentaerythritol unit bearing pendant 2,2′:6′,2″-terpyridine metal-binding domains is described; tetranuclear complexes bearing pendant carborane units are reported.