Materials Literature
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The present work deals with the atomic mechanism responsible for the emission of partial dislocations from grain boundaries (GB's) in nanocrystalline metals. It is shown that in 12 and 20 nm grain size samples GB's containing GB dislocations can emit a partial dislocation during deformation by local atomic shuffling a…
The evolution of biosynthetic pathways is difficult to reconstruct in hindsight; however, the structures of the enzymes that are involved may provide insight into their development. One enzyme in the cobalamin biosynthetic pathway that appears to have evolved from a protein with different function is L-threonine-O-3-p…
The thermal evolution and dynamics properties of small clusters in melt are investigated by molecular dynamics simulation with 500 particles. The interatomic interaction is described by a well-fitted semiempirical tight binding potential. We have studied some solidlike clusters and structural properties of liquid alum…
We demonstrate applicability of (NH4)8[Ti4(C6H4O7)4(O2)4]·8H2Owater-soluble titanium complexfor preparation of oxide materials containing titanium in the form of thin films by dip coating and fine powders by the sol−gel method. Anatase thin films and RuO2/BaTi4O9 powders were selected as examples of photocatalytic mat…
The thermodynamic and conformational properties of polymer melts grafted on a solid substrate as obtained from detailed, atomistic Monte Carlo simulations with the end-bridging algorithm are presented. The interface between a basal graphite plane (as well as a non-interacting hard surface) and a bulk polyethylene (PE)…
The surface morphology of the thermoreversible polyaniline (PANI) gels prepared with dinonylnaphthalenesulfonic acid (DNNSA), dinonylnaphthalenedisulfonic acid (DNNDSA), (±)-camphor-10-sulfonic acid (CSA), and n -dodecyloxy sulfonic acid (DOSA) are studied using atomic force microscopy (AFM) for 15% PANI concentration…
The α-relaxation process in polymethylphenylsiloxane was studied over a broad temperature and pressure range by dielectric spectroscopy. In the vicinity of the glass temperature, the shape of the dielectric loss peak is independent of both temperature and pressure. The steepness index (fragility), describing the tempe…
The adsorption and dissociation of dioxygen on the Ir(111) surface have been studied using periodic self-consistent density functional theory (DFT-GGA) calculations. Three di-σ-type chemisorbed molecular precursors are identified: One is located over bridge sites and has a binding energy of −1.3 eV and a bond length o…
[structure: see text] Tetrathiafulvalene redox-responsive ligands devoid of cis/trans isomerism containing the electroactive bis(pyrrolo[3,4-d])tetrathiafulvalene moiety and polyether subunits have been synthesized. One ligand exhibits high binding affinities for Pb2+ and Ba2+ cations as shown by independent methods (…
Despite the well-known relationship between the resonance Raman excitation profile and the absorption line shape, there is scant experimental evidence for effects in absorption or fluorescence spectroscopy related to the observations of surface-enhanced Raman scattering (SERS). On the other hand, numerous Raman studie…
Self-assembled monolayers (SAMs) of rigid biphenyl thiols are employed as heterogeneous nucleants for the crystallization of l - alanine and dl -valine. Powder X-ray diffraction and interfacial angle measurements reveal that the l -alanine crystallographic planes corresponding to nucleation are {200}, {020}, and {011}…
The reaction of the trivacant Dawson anion alpha-[P(2)W(15)O(56)](12-) and the divalent cations Co(2+) is known to form the tetracobalt sandwich complex [Co(4)(H(2)O)(2)(P(2)W(15)O(56))(2)](16-) (Co(4)P(4)W(30)). Two new complexes, with different Co/P(2)W(15) stoichiometry, [(NaOH(2))(2)Co(2)(P(2)W(15)O(56))(2)](18-)…
The new mesoporous transparent conducting oxide based on indium-tin-oxide, meso-ITO, has been synthesized by a modified sol-gel method, using CTAB as the surfactant. Critical was the employment of triethanolamine to control the rate of hydrolysis and inhibit deposition of the bulk oxides. Removal of the surfactant by…
Nanocrystals of Al 2 O 3 and Al 2 O 3 /MgO have been produced by a modified aerogel synthesis involving the corresponding aluminum tri- tert -butoxide, magnesium methoxide, toluene, methanol, ethanol, and water. The resulting oxides are in the form of powders having crystallites of about 2 nm or less in dimension. The…
Insects provide examples of many cunning stratagems to cope with the challenges of living in a world dominated by surface forces. Despite being the current masters of the land environment, they are at constant risk of being entrapped in liquids, which they prevent by having waxy and hairy surfaces. The problem is part…
A computer simulation of thermofluctuation nucleation of kinks on dislocations and their dynamics is carried out in the framework of two-dimensional (2D) Frenkel-Kontorova model. It is shown that at relatively low temperatures and applied stresses the kinks can appear as a result of developing instability of phonon mo…
The magnetic field dependence of the capacitance of Pd-AlOx-Al thin-film structures has been measured. The observed quadratic dependence of capacitance on magnetic field is consistent with a theoretical model that includes the effect of a spin-dependent electrochemical potential on electron screening in the paramagnet…
Hydrophobicity and sliding behavior of water droplets were investigated on various hydrophobic pillarlike and groove structures prepared on a silicon wafer by dicing and subsequently coating with fluoroalkylsilane. The dominant hydrophobicity mode was changed from Wenzel's mode to Cassie's mode at a smaller roughness…
The reductive coupling reactions in electrochemical polymerization of poly( p -phenylene vinylene) (PPV) have been studied by in situ UV−vis spectroscopy using lithographic galvanic microstructured metal foils (LIGA structure) as the working electrode, in situ UV−vis−ESR spectroscopy, and by the rotating ring−disk ele…
The gap in semiconductor nanocrystallites has been extensively studied both theoretically and experimentally over the last two decades. We have compared a recent ‘state-of-the-art’ theoretical calculation with a recent ‘state-of-the-art’ experimental observation of the gap in Si nanocrystallite. We find that the two a…