Materials Literature
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Abstract An experimental polypropylene (PP) nanocomposite, containing approximately 4 wt % of an organophilic montmorillonite clay, was prepared and characterized, and its properties were compared with those of talc‐filled (20–40 wt %) compositions. Weight reduction, with maintained or even improved flexural and tensi…
A rather simple method is used to detect at once both optical absorption spectra and excited-states nonradiative transitions in 0,03 at ${%}$ and 0,16 at ${%}$ ruby at temperature 2 K. The technique utilizes a time-resolved bolometer detection of phonons, generated by the excited-state nonradiative relaxation followin…
A theoretical model is proposed for low temperature friction between two smooth rigid solid surfaces separated by lubricant molecules, admitting their deformations and rotations. Appearance of different modes of energy dissipation (by ''rocking'' or ''rolling'' of lubricants) at slow relative displacement of the surfa…
We examine the dephasing rate of a Josephson charge qubit system due to background charge fluctuations. We consider single qubit and two-charge traps. The transition probability was controlled to a state where two traps were occupied. The transition probability was affected by the Coulomb blockade effect that occurs b…
The susceptibility of starch-based biomaterials to enzymatic degradation by amylolytic enzymes (glucoamylase and alpha-amylase) was investigated by means of incubating the materials with a buffer solution, containing enzymes at different concentrations and combinations, at 37 degrees C for 6 weeks. Two polymeric blend…
An adiabatic approach is developed for the problem of boundary friction between two atomically smooth and incommensurate solid surfaces, separated by a monolayer of lubricant atoms. This method permits to consider very slow macroscopic motion of the parts in contact, separately from fast thermic motions of individual…
We present micromagnetic results for the hysterisis of a single magnetic nanopillar which is misaligned with respect to the applied magnetic field. We provide results for both a one dimensional stack of magnetic rotors and of full micromagnetic simulations. The results are compared to the Stoner-Wohlfarth model.
For one-dimensional many-body systems interacting via the \textit{Coulomb force} and with \textit{arbitrary} external potential energy, we derive (\textit{i}) the \textit{node coalescence condition} for the wave function. This condition rigorously proves the following: (\textit{ii}) that the particles satisfy \textit{…
A one-flask synthesis of meso-substituted dipyrromethanes has been refined. The procedure entails reaction of an aldehyde in 100 equiv of pyrrole as the solvent containing a mild Lewis acid (e.g., InCl 3 ) at room temperature. Following removal and recovery of excess pyrrole, the dipyrromethane is obtained by crystall…
Surface sol-gel process was used to replicate the hierarchical morphology of natural cellulosic substances with nanometer precision. The resultant artificial fossils are ceramic nanomaterials composed of metal oxide nanotubes.
Individual single-walled carbon nanotubes (SWNTs) have been suspended in aqueous media using various anionic, cationic, nonionic surfactants and polymers. The surfactants are compared with respect to their ability to suspend individual SWNTs and the quality of the absorption and fluorescence spectra. For the ionic sur…
Abstract As part of our continuing studies concerned with the elucidation of the crosslinking polymerization mechanism leading to interpenetrating polymer network (IPN) formation, in which IPNs consist of both polymethacrylates and polyurethane (PU) networks, this article explores the polyaddition crosslinking reactio…
The lanthanide–chlorine bond length, Re, and the frequency of the symmetric stretching mode, ν̄a1g, of the (LnCl6)3− octahedral defect clusters embedded in Cs2NaYCl6 have been calculated for all 14 Ce3+ to Lu3+ impurities in their ground 4fn electronic state using wave-function-based ab initio methods of solid state q…
Optical absorption measurements on different growth sectors of a polished slice of electron-irradiated type Ib synthetic diamond show that the vacancy concentration is almost four times higher in the high-nitrogen {111} sectors than in the low-nitrogen {115} sectors. Evidence is presented to show that the self-interst…
The distribution of gallium and germanium over the available framework sites in the type-I clathrate Sr 8 Ga 16 Ge 30 ( Pm \bar{3} n ) has been determined by powder diffraction using several different combinations of resonant scattering data sets, collected at energies close to both the Ga and Ge K -edges, and time-of…
Abstract Eu2+ ions were incorporated into SiO2–BaMgF4 glass–ceramic thin films using a sol–gel method. The addition of N,N-dimethylformamide to a starting solution resulted in a porous microstructure of the film prepared. The films exhibited blue emission peaking at 420 nm by excitation at 290 nm. The emission was eff…
We report the parameter-free, density-functional theory calculations of the electronic structure, interatomic exchange interaction and magnetic critical temperature of Zn 0.75 Cr 0.25 Te. This system has recently gained exceptional importance as the first diluted magnetic semiconductor (DMS), where the intrinsic ferro…
Abstract Polyolefins and chlorine‐containing polymers were investigated to produce polymer nanocomposites. Natural and organic‐treated montmorillonite clays were melt compounded with the polymers. Organic‐treated montmorillonite clay dispersed well in polychloroprene, chlorinated‐polyethylene, polyvinyl chloride, chlo…
The role of the bridging ligand on the effective Heisenberg coupling parameters is analyzed in detail. This analysis strongly suggests that the ligand-to-metal charge transfer excitations are responsible for a large part of the final value of the magnetic coupling constant. This permits us to suggest a variant of the…
Domain structures in [001]-poled rhombohedral phase 0.68Pb(Mg1/3Nb2/3)O3–0.32PbTiO3 single crystals have been investigated using polarized light microcopy. It was found that the observed domain structures are quite different from those previously assumed four domain states with cross intersecting 71° charged domain wa…