Materials Literature
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Oxidative polymerization of 2,6-disubstituted phenols has been performed by using iron(III)-salen complex and hydrogen peroxide as catalyst and oxidizing agent, respectively. The oxidative reaction of 2,6-dimethylphenol produced the polymer along with a byproduct dimer of 3,5,3',5'-tetramethyl-4,4'-dipheno-quinone. Th…
The Fe57 nuclear magnetic resonance (NMR) shielding and chemical shift in ferrocene, Fe(C5H5)2, are studied using density functional theory (DFT) and gauge-including atomic orbitals (GIAO). Electronic factors contributing to the chemical shift are discussed in detail. It is shown that the chemical shift is entirely de…
We report a detailed crystal-field splitting analysis of the energy levels of Dy3+(4f9) in single crystals of Dy2S3 that have the Th3P4 cubic defect structure. From an analysis of the temperature-dependent absorption spectra, we have identified seven of the eight crystal-field split energy (Stark) levels of the ground…
We have studied by X-ray reflectometry the variation of electron density of thin polymer films near solid substrates. For most polymers studied, which interact only mildly with the selected substrate (SiO 2 ), a decrease of density was detected over a region spanning two to three statistical segment lengths at the sol…
The structures and coalescence behavior of size-selected, matrix-isolated silicon clusters have been studied using surface-plasmon-polariton (SPP) enhanced Raman spectroscopy. The cluster ions were produced in a laser vaporization source, mass selected then deposited into a co-condensed matrix of Ar, Kr or N2 on a liq…
Ultrathin poly(vinyl alcohol) (PVA) films were fabricated on a gold substrate by a repetitive process based on physical adsorption from aqueous solution in the presence of NaCl and subsequent drying. A quartz crystal microbalance (QCM) was used to analyze the assembled amount quantitatively. The assembled amount incre…
The spin-lattice relaxation time T1 of simple organic glass formers is analyzed by introducing a spectral density obtained from broadband dielectric susceptibility data χ″(ω). For this purpose χ″(ω) was measured for several glass formers, that do not exhibit a Johari-type secondary relaxation process, covering a frequ…
The polarization spectra of template-synthesized colloidal gold rods with aspect ratios ranging from L / d = 1.8 to 49 (and a diameter d = 15 nm) embedded in poly(vinyl alcohol) (PVA) films are studied as a function of the film elongation. Orientation of the colloidal gold rods is obtained by stretching the PVA films.…
We present a theoretical analysis of the effect of dielectric confinement on the Coulomb interaction in dielectrically modulated quantum structures. We discuss the implications of the strong enhancement of the electron-hole and electron-electron coupling for two specific examples: (i) GaAs-based quantum wires with rem…
The steroidogenic acute regulatory protein (StAR) increases the movement of cholesterol from the outer to the inner membrane of adrenal and gonadal mitochondria, thus providing the substrate for steroid hormone biosynthesis. Deletion of 62 amino-terminal aa produces a cytoplasmic form of StAR (N-62 StAR) that lacks th…
ZnSe epilayers were grown on GaAs (001) substrates by metal organic chemical vapor phase deposition, using different group VI–II precursor flow ratios. Atomic force microscopy (AFM) examinations of their surface show that epilayers grown with a high VI/II ratio are not as stable as those grown with a low ratio. When e…
Electrodeposited polypyrrole films were formed on chemically modified hydrogen-terminated silicon surfaces that expose tethered pyrrole units. Semiconductor/polypyrrole junctions on the native and modified substrates exhibit diode-like characteristics, with those on the latter substrate exhibiting higher current densi…
Crystalline silicon nanoparticles (quantum dots) with diameters around 4 nm are produced via CO2-laser-induced decomposition of SiH4 in a flow reactor and subsequently transferred into a freely propagating cluster beam. Thin structured films are then obtained by shaping the beam with a mask and depositing the nanoclus…
Thermal composition fluctuations and the associated crossover from the 3D Ising to the isotropic Lifshitz universality class have been studied in a three component mixture made of a critical polymer blend and the corresponding diblock copolymer. The critical exponents were found to be appreciably larger than those of…
Strong electro-optical (EO) anisotropy has been measured in (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 [(1−x)PMN–xPT] single crystalline films epitaxially grown on (100)-cut LaAlO3 substrate, through using an improved dynamic alternating-current ellipsometric null EO detection technique with high accuracy. Large quadratic EO coeff…
We report on the thermoelectric properties of two ternary tellurides with known crystal structures. Both compounds have a very low lattice thermal conductivity. Tl2SnTe5 appears to have a p-type figure of merit about the same as that of Bi2Te3, the best thermoelectric material among binary compounds. We have synthesiz…
Surface relief gratings have been optically inscribed on azopolymer films on the interior surface of an empty liquid crystal (LC) cell. Uniform LC alignment is observed in the inscribed regions when the cell is filled. Since the microgrooves are on both sides, this may provide a higher degree of order than other techn…
We applied the technique of focal-series reconstruction in high-resolution electron microscopy for a precise determination of the spacings between atomic columns at a $\ensuremath{\Sigma}3$ ${111}$ twin boundary in perovskite ${\mathrm{BaTiO}}_{3}$. We succeeded in observing a predicted expansion of the nearest Ti-Ti…
Synchrotron x-ray diffraction measurements have been made on hexagonal crystal Ti3SiC2 under pressures up to 61 GPa and at room temperature. No phase transition was observed within the pressure range studied. Both the a and c axes exhibited decreases with pressure, accompanied by a decrease in the c/a ratio to about 5…
The blue mixed-crystal title compound Na15[MoMoO462H14 (H2O)70]0.5[MoMoO457H14 · (H2O)68]0.5 · ca. 400 H2O ≡ Na15[1 a]0.5[1 b]0.5 · ca. 400 H2O 1, which crystallizes in the triclinic space group P 1 (a = 30.785(2), b = 32.958(2), c = 47.318(3) Å, α = 90.53(1), β = 89.86(1), γ = 96.85(1)°, V = 47665(6) Å3, Z = 2, Dcalc…