Materials Literature
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An organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA), exhibits a first-order phase transition between a paramagnetic high-temperature (HT) phase and a diamagnetic low-temperature (LT) phase, with a surprisingly wide thermal hysteresis loop over the temperature range 230--305 K. The crystal structure of the…
Binary mixtures of the aggregating helicene 1 with dodecane have, at dodecane concentrations >30 vol %, a nematic liquid crystalline phase and, at dodecane concentrations ≲5 vol %, a hexagonal columnar liquid crystalline phase. The helical structure with donor and acceptor groups at opposite ends gives rise to a molec…
The XPS (ESCA) method was employed to quantitatively determine polyelectrolyte adsorption on the mica basal plane from low ionic strength solutions. Particular emphasis was given to the effect of the polyelectrolyte charge density. By combining the results obtained from XPS and surface force measurements it was possib…
Water and oxygen molecules determine many of the properties of amorphous SiO2 used in several technologies, but the underlying atomic-scale processes remain unresolved. We report results of first-principles calculations showing that a wide range of behavior is possible in an amorphous environment, including diffusion…
Long-range effects on the pyroelectric coefficient of a ferroelectric superlattice consisting of two different ferroelectric materials are investigated based on the Transverse Ising Model. The effects of the interfacial coupling and the thickness of one period on the pyroelectric coefficient of the ferroelectric super…
Abstract Raman spectroscopy was used to determine the molecular behaviour of DMSO and DMSO‐ d 6 , and to compare it with that of DMSO in DMSO‐intercalated kaolinites. For DMSO at 298 K two bands are observed at 2994 and 2913 cm −1 and are assigned to the antisymmetric and symmetric CH stretching modes. At 77 K the deg…
Abstract Tensile tests on poly (methyl methacrylate) (PMMA) were conducted to clarify the effects of humidity and strain rate on tensile properties, particularly Young's modulus. Prior to the tensile tests, specimens were kept under various humidity conditions at 293 K, which were the same as the test conditions, for…
We derive a drift-diffusion equation for spin polarization in semiconductors by consistently taking into account electric-field effects and nondegenerate electron statistics. We identify a high-field diffusive regime which has no analogue in metals. In this regime there are two distinct spin diffusion lengths. Further…
Atomistic studies are carried out to investigate the formation and evolution of defects during nanoindentation of a gold crystal. The results in this theoretical study complement the experimental investigations [J. D. Kiely and J. E. Houston, Phys. Rev. B, v57, 12588 (1998)] extremely well. The defects are produced by…
The ferromagnetic resonance spectrum of a normally magnetized YIG disk, with thickness of 4.75$μ$m and radius of 80$μ$m, is measured at room temperature both by magnetic resonance force microscopy and by standard detection of the microwave susceptibility. The comparison indicates that MRFM represents one of the most p…
Many crystalline materials show chemical short range order and relaxation of neighboring atoms. Local structural information can be obtained by analyzing the atomic pair distribution function (PDF) obtained from powder diffraction data. In this paper, we present the successful extraction of chemical short range order…
It has been shown that under joint action of DC magnetic and AC electric fields neutral particles (atoms,molecules,nano-size particles etc.) nearby interface move with permanent velocity along the surface. The driving force depends on non-linear dynamical properties of polarization of the particles and a coupling betw…
We present results of molecular-dynamics simulations for a nonentangled polymer melt confined between two completely smooth and repulsive walls, interacting with inner particles via the potential U(wall)=(sigma/z)(9), where z=/z(particle)-z(wall) and sigma is (roughly) the monomer diameter. The influence of this confi…
Thermal treatment of Zn(NH3)(4)2+ precursor in ethanol solvent led to the formation of the tubular ZnO which exhibited strong ultraviolet photoluminescence around 385 nm at room temperature; TEM images showed the hollow tubules with approximately 450 nm in diameter and approximately 4 microns in length were built up b…
Adsorption in spherical cavities is studied by the nonlocal density functional theory (NLDFT). Theoretical results are compared with experimental data on ordered nanoporous materials with cubic Pm 3 n (SBA-1, HMM-3), cubic Im 3 m (SBA-16), and 3D hexagonal P 6 3 / mmc (SBA-2, SBA-12) cagelike structures. Quantitative…
The low-temperature alloying of Fe-Ag nanoparticles entrapped within thermally evaporated fatty acid films by a novel ion exchange technique is described. Nanoparticles of iron and silver were grown in thermally evaporated stearic acid (StA) films by sequential immersion of the film in solutions containing Fe 2+ ions…
This is a report on the construction and the main features of an X-ray camera following the Debye–Scherrer geometry, combined with a sample mounting and rotation device for single crystals as first suggested by Gandolfi. Doubling of the camera radius and replacing of the wet-film technology by a highly dynamic imaging…
The molecular orientation in as-spun fibers of main-chain thermotropic liquid crystalline polymers (TLCP) has been investigated using electron diffraction at high spatial resolution. Although a large degree of macromolecular alignment with the fiber axis is expected due to the large shear stress and elongational flow…
Femtosecond transient absorption studies were conducted for self-assemblies between oppositely charged metal-substituted 18-crown-6 tetrasubstituted phthalocyanines (McrPc) and metal-substituted meso -(4-sulfophenyl)-porphine (MTPPS) or meso -(4-carboxylphenyl)-porphine (MTPPC). Excitation could be carried out at 400…
The circumstances leading to the present worldwide explosion of interest in molecule–based magnetic materials are summarized. Interactions between developments in inorganic coordination and solid–state chemistry with developments in condensed–matter physics are identified as key factors in the emergence of this new fi…