Materials Literature
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Magnetization measurements along the main symmetry directions of the tetragonal structure, [100], [110] and [001], have been performed on several single crystals (R = Y, Tb and Ho), at applied high magnetic fields up to 12 Tesla and temperatures ranging from 4.2 to 300 K. From the measurements on the yttrium compound…
Thin films composed of a layered titanate were prepared by a so-called soft-chemical method that took advantage of exfoliation of the layered material Cs x Ti (2 - x /4) □ x /4 O 4 . The exfoliated titanate sheets were easily oriented on a substrate by means of spin-coating. The prepared thin films had a layered struc…
High-temperature polymeric foams were prepared using compositionally asymmetric microphase-separated block copolymers where the major component is thermally stable and the minor component is thermally labile. Upon thermal treatment, the dispersed phase undergoes thermolysis leaving pores the size and shape of which ar…
The dynamic structure factor of the glass formers glycerol, o-terphenyl, and n-butyl-benzene has been studied by inelastic x-ray scattering across the liquid-glass transition. Data taken at selected temperatures in the $1--8{\mathrm{nm}}^{\ensuremath{-}1}$ momentum transfer ( $Q$) range show a propagating soundlike mo…
Levan, which adopts a compact spherical conformation in aqueous solution, can form a liquid crystalline phase if DNA is also present. We propose that supramolecular rodlike structures, assembled by the noncovalent aggregation of levan around DNA, stabilize the lyotropic phase. We describe a geometric model for the agg…
The synthesis, structure, and electronic properties of a series of new quaternary layered sulfides, NaCuMS 2 (M = Mn, Fe, Co, Zn) are reported. The synthesis was accomplished by sulfurization of a mixture of oxide or sulfide and carbonate precursors of the corresponding metals by nitrogen gas charged with CS 2 . All o…
By a simple washing of vaterite with ultrapure water, it transforms rapidly into cubic calcite. When the solid is washed with Cu 2+ solutions, the transformation depends on the concentrations of the copper solutions applied in the process. For concentrations of 10 - 4 mol dm - 3, a certain delay in the transformation…
Using a combination of microscopy, powder X-ray diffraction, and model building, we recently reported evidence for the first misfit layer oxide, Tl 0.41 (Sr 0.9 O) 1.12 CoO 2 (Boullay et al. Chem. Mater. 1996, 8, 1482). In this work, we present a more detailed structural characterization from an additional high-resolu…
Self-assembled functional molecules in mesostructured materials (MM) are synthesized directly either by coassembly of dye-bound surfactant of ferrocenyl TMA with silicate or by Pc (phthalocyanine) molecules doped within C 16 TMA micelles assembled with oxides framework such as vanadia (VO x ), MoO 3, WO 3, and SiO 2 t…
This work synthesizes new diamantane-based polyimides by reacting 4,9-bis(4-aminophenyl)diamantane ( 4 ) with various aromatic tetracarboxylic dianhydrides. Poly(amic acid)s have high inherent viscosities of 0.74−1.36 dL/g. The polyimide 7 d can be soluble in o -chlorophenol, chloroform, and THF. Their cast films have…
The Pd-catalyzed cross-coupling reaction involving organostannanes (Stille reaction) is applied to prepare a series of N - t -BOC-protected D−π− A oligopyrroles. After purification, oligomers with one to four pyrrole units inserted between a 4-nitrophenyl and a 4-methoxyphenyl group are isolated in yields between 20 a…
The high-field dielectric properties of a commercial cobalt-doped piezoceramic were determined by analysis of P - E (polarization-electric field) hysteresis loops. Measurements recorded under a continuous high AC field (amplitude ) established that the material underwent a diffuse ferroelectric phase transformation at…
The pyrolytic transformation of hybrid gels, obtained by hydrolysis−condensation of diethoxydimethylsilane and zirconium n -propoxide mixtures with different Si/Zr ratio, has been studied using TG−GC−MS coupled techniques, FTIR spectroscopy, and N 2 adsorption analysis. The starting gels have been described as nanocom…
Conformation of a flexible linear polymer (polyacrylic acid, PAA) in a binary mixture ( $\mathrm{water}+2$,6-lutidine, LW) near the critical point of LW is studied using dynamic light scattering (DLS) by which the diffusivities of the polymer molecules and the critical composition fluctuation of the LW are measured. T…
A self-regulation hydrothermal reaction to synthesize nanocrystalline zinc gallate (ZnGa2O4) complex oxides was proposed: The Zn2+ ion concentration and the pH value of the solution and the nucleation and growth of ZnGa2O4 were well auto-controlled under these simple hydrothermal conditions.
A series of nondiscoid rhodium and iridium dicarbonyl β-diketonate complexes have been shown to organize in columnar liquid crystal phases with hexagonal disordered structures (Col hd ). The shape and dipolar attributes of these materials produce highly correlated antiparallel pairwise arrangements. This organization…
Neutron diffraction has been used to determine the two P-O bond lengths which occur in the threefold-linked tetrahedral structural units of vitreous . The large maximum momentum transfer which is available on the LAD instrument at the ISIS spallation neutron source gives high real-space resolution which enables a clea…
Using a “two-steps” synthesis mode, the homogeneity ranges of the perovskites Ln 1 - x Ba x MnO 3 were extended up to x = 0.60 for the Pr-based samples and x = 0.50 for the La ones. Two new perovskites, a cubic form and a P-type tetragonal phase (with a C × a C × 2 a C parameters) have been isolated. The HREM study sh…
Intense ultraviolet photoluminescence centered at 370 nm was observed from magnetron-sputtered silicon oxide films after they were annealed at about 1000 °C in N2 atmosphere. This photoluminescence is found to be associated with the formation of nanocrystal silicon particles in the specially structured SiO2, which hig…
Silica/surfactant mesophases have been synthesized in 14 water:cosolvent mixtures by combining tetramethoxysilane with a basic 2 wt % CTAB solution. The effects of the water-to-cosolvent ratio on the formation of supramolecular surfactant templates and ultimately silica/surfactant mesophases is reported for: diethyl e…