Materials Literature
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To obtain insights into a correlation relationship between the structure and the aggregation mode in an organogel system, we synthesized gelators 2a-4a bearing a porphyrin moiety as a one-dimensional aggregation unit and amide groups as peripheral hydrogen-bonding sites. Gelators 3a and 3b bearing the amide groups at…
We demonstrated an amplification phenomenon in a bismuth-doped silica glass at 1.3 μm with 0.8-μm excitation. This luminescent material is a promising candidate for use as the core-fiber material of an optical amplifier at the natural zero-dispersion wavelength (1.3 μm) of silica glass fiber.
This paper describes a systematic study of ferromagnetic resonance (FMR) carried out on a series of specimens of the ferromagnetic semiconductor ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ in thin film form. The GaMnAs layers were grown by low-temperature molecular beam epitaxy either on GaAs or on…
Strain-gradient-induced polarization or flexoelectricity was investigated in unpoled soft lead zirconate titanate (PZT) ceramic where the texture symmetry m∞∞ forbids macropiezoelectricity. Even under high strain gradient (1 m−1) the induced polarization is small (1.6 μC/m2) at 20 °C. Higher strain gradients induce fe…
Perturbation in the energy-transfer pathway and of the π conjugation between the chromophores in a triarylborane–porphyrin conjugate on coordination of a fluoride ion to the boron center is assumed to account for the observation of the three emission bands (at 356, 670, and 692 nm). The system also displays a colorime…
Epoxides are an important class of industrial chemicals that have been used as chemical intermediates. Catalytic epoxidation of olefins affords an interesting production technology. We found a widely usable green route to the production of epoxides: A silicotungstate compound, [gamma-SiW10O34(H2O)2]4-, is synthesized…
Abstract A series of fractions of a hyperbranched polyester in deutero tetrahydrofuran solution were investigated by small‐angle neutron scattering. Concentrations of polymer from 2 to 5% w/v were used, and the molecular parameters were obtained from Zimm plots of the data. Second virial coefficients were positive, an…
High-pressure polymorphs of WO 3 have been studied with a first-principles pseudopotential method. The medium-range (0.01–20 GPa) and high-range (20–30 GPa) polymorphs have been characterized and are compared with recent experimental results. The main new feature is the appearance of a sevenfold coordinated tungsten i…
Rumpled surface structure and root mean square (rms) thermal vibration amplitudes of NiO(001) were determined by high-resolution medium energy ion scattering. The clean 1\ifmmode\times\else\texttimes\fi{}1 surface was prepared by cleavage in the air and annealing at 500 \ifmmode^\circ\else\textdegree\fi{}C for 40 min…
Sharp absorption lines produced by hydrogen in diamond have been studied in diamonds grown from C-13 by high-pressure, high-temperature synthesis. Analyses of the two-phonon intrinsic absorption and of the Raman shift have shown that the C-12 content of the diamond is 13.5%. This value is entirely consistent with the…
For Ce 3+ , Er 3+ and Yb 3+ ions, electron paramagnetic resonance (EPR) spectra typical for S ' = 1/2 ions are measured for YAl 3 (BO 3 ) 4 (YAB) single crystal. The spectra show axial symmetry indicating that all three dopants replace Y 3+ at the given dopant concentration. Corresponding - and hyperfine Ã-tensors are…
The technical feasibility of separating and decomposing CO 2 in the context of a novel energy generation cycle during the operation of a glass furnace was investigated. The concept envisions CO 2 decomposition to take place in a membrane reactor utilizing high-temperature solid-oxide membranes with the aid of oxygen c…
Semimetallic antimony nanotubes were synthesized via a hydrothermal reduction method at 120°C using zinc powder as the reducing agent. X-ray powder diffraction and energy dispersive x-ray analysis showed that the as-prepared sample was elemental antimony. High-resolution transmission electron microscopy characterizati…
We report on polarized Raman scattering of single crystals of Nd 1− x Sr x MnO 3 ( x = 0.3, 0.5). Raman spectra of Nd 0.7 Sr 0.3 MnO 3 show a significant change through the metal–insulator transition. In the ferromagnetic metallic phase phonon modes grow in intensity and number while the electronic continuum becomes m…
The wetting of a solid surface by a liquid is dramatically impeded if either the solid or liquid is decorated by particles. Here, we show that in the case of contact between two liquids the opposite effect can occur; mixtures of a hydrophobic liquid and suitable particles form wetting layers on a water surface, though…
Abstract A hyperbranched polyester was fractionated by precipitation to produce 10 fractions with molecular weights between 20 × 10 3 and 520 × 10 3 g mol −1 . Each of these fractions was examined by size exclusion chromatography, dilute‐solution viscometry, intensity, and quasi‐elastic light scattering in chloroform…
The single substitutional nitrogen atom in diamond is apparently a very simple defect in a very simple elemental solid. It has been modelled by a range of computational models, few of which either agree with each other, or with the experimental data on the defect. If the computational models of less well understood de…
Microwave plasma deposited (100) diamond films have been thermally oxidized in dry O2 between 500 and 723 degrees C. The roughness of a single crystalline grain following oxidation is consistent with a layer-by-layer mechanism for the removal of carbon monoxide. The resulting surface exhibits infrared absorption bands…
The formation, crystal structure and magnetic properties of Sm2Fe17−xCoxCy were studied. The substitution of Co for Fe helps to stabilize the rhombohedral Th2Zn17-type structure (2:17) and eliminate α-Fe formation for carbon concentrations y ≤ 1.5. From the mixing enthalpy calculations based on Miedema's semi-empirica…
Man’s environment is pervaded by ionizing radiation of predominantly natural origin but now with an important contribution from anthropogenic activities. Exposure to ionizing radiation can have serious health implications, which is why it is of concern to us. This book brings together under one cover, the fundamentals…