Materials Literature
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Ample experimental evidence has been accumulated demonstrating that the formation of monodispersed colloids proceeds through a more complex mechanism, than the generally excepted diffusional "burst nucleation" process. Instead, the synthesis of narrow-size-distribution colloidal dispersions involves several stages, i.…
We devise a two dimensional model that mimics the recently observed power law distributions for the amplitudes and durations of the acoustic emission signals observed during martensitic transformation [ Vives {\it et al}, Phys. Rev. Lett. {\bf 72}, 1694 (1994)]. We include a threshold mechanism arising from the atherm…
Calculations based on density functional theory (DFT) have been carried out to investigate the electronic and magnetic properties of the alpha-Keggin anions mentioned in the title. The atomic populations and the distribution of the electron density computed for the studied clusters support the hypothesis that an oxidi…
A set of iron(II) complexes that exhibit a temperature-dependent spin-crossover between the low-spin and the high-spin state were studied by density functional methods. The total electronic energy, the zero-point vibrational energy, and the entropy were calculated in order to determine the free energy. While the calcu…
A new synthetic method was developed to produce robust, highly crystalline, organic-monolayer passivated silicon (Si) nanocrystals in a supercritical fluid. By thermally degrading the Si precursor, diphenylsilane, in the presence of octanol at 500 degrees C and 345 bar, relatively size-monodisperse sterically stabiliz…
Plastic wastes, which cause a serious environmental problem in urban areas, can serve as sources of energy. Catalytic treatment of High Density Polyethylene (HDPE) has shown that the degradation of HDPE resulted in the production of a stream of gaseous hydrocarbons varied in the range C1-C8. The degradation was carrie…
Abstract This article establishes the processing–microstructure–motion–property relationship of high‐speed melt‐spun nylon‐6 fibers. From solid‐state 1 H NMR T 1ρ (spin–lattice relaxation time in the rotating frame) relaxation studies, all nylon‐6 fibers spun at 4500–6100 m/min showed three‐component exponential decay…
Abstract Chitosan (chitosan acetic acid salt) and whey (65% protein) films were coated with a nitrocellulose lacquer or laminated with polyethylene to enhance their water resistance and gas barrier properties in humid environments. The barrier properties were measured by the Cobb 60 test and water‐vapor (100% relative…
The diamond-to-\ensuremath{\beta}-tin phase transitions of Si and Ge under uniaxial compression are investigated with ab initio calculations. A thermodynamic analysis is used to identify the transition pressures at uniaxial compression. The transition pressures were found to be pronouncedly lower than those at hydrost…
The depletion interaction between two parallel repulsive walls confining a dilute solution of long and flexible polymer chains is studied by field-theoretic methods. Special attention is paid to self-avoidance between chain monomers relevant for polymers in a good solvent. Our direct approach avoids the mapping of the…
In this work, we present the results of the investigation of the effect of prolonged cycling on the hydriding/dehydriding properties and on the structure of nanocrystalline MgH 2 −V composite under hydrogen containing 110 ppm of carbon monoxide. The hydrogen charge and discharge kinetics of the nanocomposite hydride w…
An experimental study showed the enhancement effect of di- tert -butyl peroxide on poly(α-methylstyrene) (PAMS) thermal degradation in trichlorobenzene solution (12.5 g/L). Peroxide was continuously injected into the reacting polymer solution at low flow rates (0.3−4.0 mL/h). Samples were taken periodically and analyz…
The cis-doubly N-confused porphyrin, H2N2CP, containing two adjacent confused pyrrole rings has been investigated from the point of view of its acid-base and electrochemical behavior in dichloromethane. This novel porphyrin isomer can form two metal-carbon bonds in the central core, stabilizing metal ions in unusually…
An approach to generate inversion walls in nematic liquid crystals using optical reorientation is described. Planar cells with small pretilt are exposed to an oblique laser beam, which reverses the director tilt angle within the irradiated area. During the electric Freedericksz transition an inversion wall surrounding…
The changes in the structure and catalytic activity of three iron oxides (α-FeOOH, γ-Fe 2 O 3, and an Fe 3 O 4 −C composite) were studied by temperature-programmed desorption/degradation (TPD) and XRD analysis. Thermal desorption analysis was performed for the fresh iron oxide catalysts. Thermal degradation experiment…
The results of an assessment of the state-of-the-art in the design and manufacturing of large composite structures are described. The focus of the assessment is on the use of polymeric matrix composite materials for large airframe structural components, such as those in commercial and military aircraft and space trans…
The tetrabutylammonium gamma-dodecatungstosilicate has been crystallized in a 6/1 acetonitrile/water solvent. An X-ray single-crystal analysis was carried out on [N(C4H9)4]4-gamma-[SiW12O40] which crystallizes in the orthorhombic system, space group P2(1)2(1)2(1), with a = 19.0881(3) A, b = 21.4435(3) A, c = 26.0799(1…
The interaction between swift charged particles and the electronic surface modes of a cylindrical cavity is described according to classical and quantum-mechanical formulations. We perform a quantization of the collective modes and obtain expressions for the coupling with external probes moving with arbitrary trajecto…
A variety of naturally occurring biomaterials owe their unusual structural and mechanical properties to layers of beta-sheet proteins laminated between layers of inorganic mineral. To explore the possibility of fabricating novel two-dimensional protein layers, we studied the self-assembly properties of de novo protein…
The mononuclear PPh4[Fe(phen)(CN)4]*2H2O (1) complex and the cyanide-bridged bimetallic [[Fe(phen)(CN)4]2M(H2O)2]*4H2O compounds [M = Mn(II) (2) and Zn(II) (3); phen = 1,10-phenanthroline; PPh4 = tetraphenylphosphonium cation] have been synthesized and structurally and magnetically characterized. Complex 1 crystallize…