Materials Literature
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The isotropic–nematic phase transition in a fluid of hard spherocylinders with a spherocylindrical square-well attraction is examined using Monte Carlo simulations and two theoretical approaches. The first theory is a first-order perturbation theory which incorporates the Parsons decoupling approximation for the pair…
A new aromatic tetracarboxylic dianhydride having a crank and twisted noncoplannar structure, 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, was synthesized by the reaction of 4-nitrophthalonitrile with biphenyl-2,2′-diol, followed by hydrolysis and cyclodehydration. The biphenyl-2,2′-diyl-containing aromatic pol…
We investigate the molecular mechanism of secondary nucleation on a growth surface of the polymer crystal. We adopt a simplified model of polyethylene molecule made of 500 beads connected by springs, and consider the crystallization from a vapor phase neglecting surrounding molecules. A strongly collapsed chain in a v…
A miscibility phase diagram of mixtures of UV-curable multifunctional thiolene-based optical adhesive (NOA65) and low molar mass 4- n -heptyl-4-cyanobiphenyl nematic liquid crystal (K21) has been established using light scattering, optical microscopy, and differential scanning calorimetry. The emergence of phase morph…
Surface relaxations and electronic structures of (001) surfaces of cubic ${\mathrm{SrTiO}}_{3}$ have been studied by first-principles total-energy calculations with the generalized-gradient approximation. Both ${\mathrm{TiO}}_{2}$-terminated (surface-I) and SrO-terminated (surface-II) surfaces are investigated and the…
Magneto-optical Kerr effects have been investigated for perovskite-type hole-doped oxides ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3} (0<~x<~0.3)$ and ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{3} (0<~x<~0.3)$ in the photon energy range between 0.9 and 5.3 eV…
We use tight-binding total-energy calculations to investigate the energetics and the cap formation mechanism of single-walled carbon nanotubes. The present calculations of the edge energy and strain energy suggest the growth of armchair nanotubes to be energetically more favorable than the growth of zigzag nanotubes.…
The yield stress behavior of a range of polyethylene materials which differ with respect to their short chain branch content has been studied. Measurements carried out over a wide range of temperatures have shown that there is a sudden transition in the behavior of the yield stress at a temperature which is dependent…
Au/SrTiO 3 (STO), Au/YBa2Cu3O7−x (YBCO)/STO, Au/STO/CeO2/STO, and Au/STO/MgO/STO multilayer structures on LaAlO3 substrates have been fabricated. Their properties are investigated at 1 MHz and at microwave frequencies (40 MHz–40 GHz) as a function of applied voltage, and in the temperature range between 20 and 300 K.…
A structural analysis of six alkaline sodium aluminate aqueous solutions by the X-ray diffraction method is reported. On average, each Al atom is surrounded by four oxygens, indicative of the predominance of Al(OH) 4 - (aq) in these solutions. Detailed least-squares fitting indicates that a significant contraction of…
The voltage-dependent dielectric constant (ε) of SrTiO3 (STO) thin films is the basis for developing cryogenic capacitors for tunable microwave applications. In this study, the effect of microwave signal level on nonlinear response at 1.7–1.9 GHz was examined by measuring the level of the third order intermodulation d…
We have studied the influence of the anodization temperature on the formation of porous Si for different current intensities. We have monitored the porosity, growth rate, luminescence, refractive index, and porous Si/bulk Si interface roughness. A strong decrease of the roughness was obtained for low temperature anodi…
Ferroelectric thin films (∼1.2 μm) of BaxSr1−xTiO3 with gradients in composition normal to the growth surface were formed on platinum substrates by metalorganic decomposition. Effective (pseudo) pyroelectric coefficients as large as 0.06 μC/cm2 K have been obtained from these active ferroelectric devices under the app…
A series of mononuclear transition metal complexes of the tetradentate (N 2 O 2 ) 6,6‘-bis(3‘‘-oxide-1‘‘-oxyl-4‘‘,4‘‘,5‘‘,5‘‘-tetramethylimidazoline-2‘‘-yl)-2,2‘-bipyridine (NIT-bpy) has been prepared and characterized by spectroscopic, magnetic, and single-crystal X-ray diffraction studies. The free NIT-bpy ligand is…
${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ (LCMO) thin films are grown by pulsed laser deposition on a (100) ${\mathrm{SrTiO}}_{3}$ substrate at temperatures between 530 and 890 \ifmmode^\circ\else\textdegree\fi{}C. The magnetotransport prop…
Electrochemical measurements of hydrogen permeation through Pd/Nb multilayers on Pd substrates are described. Pronounced retardation of permeation is observed for small hydrogen contents. To clarify whether this effect is due to special interface hydrogen states, the permeation is modeled based on the bulk properties…
Electrically conducting polypyrrole-treated films have recently been shown to influence the morphology and function of mammalian cells in vitro. This type of polymer represents a possible alternative biomaterial for use in vascular implantation. The present study compared the in vitro biocompatibility of the five diff…
The real ( ε 1 ) and imaginary ( ε 2 ) parts of the dielectric function of polycrystalline samples of monoclinic CuO have been measured by spectroscopic ellipsometry in the 1.2–5.0-eV photon-energy range at room temperature. The CuO crystals having a grain size of the order of 1×1 mm 2 were successfully grown by a flo…
Poly(vinyl acetate- co -vinyl alcohol) copolymers (P(VAc- co -VA)) were synthesized by hydrolysis−alcoholysis of PVAc. The miscibility, crystallization, and morphology of poly(β-hydroxybutyrate) (PHB) and P(VAc- co -VA) blends were studied by differential scanning calorimetry, optical microscopy (OM), and SAXS. It is…
We present a comprehensive study of the aging process in HCl-doped polyaniline exposed to air. A complete set of measurements was carried out on three series of samples stemmed from the same preparation batch, and aged at 100, 120, and 140 \ifmmode^\circ\else\textdegree\fi{}C for times up to one month. All the samples…