Materials Literature
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We report the observation of visible photoluminescence and cathodoluminescence of Eu3+ ions implanted in GaN and Al0.14Ga0.86N/GaN superlattice. The sharp characteristic emission lines corresponding to Eu3+ intra-4f6-shell transitions are resolved and observed over the temperature range of 7–330 K. The luminescence sh…
Certain porous-silicon (PS) films exhibit well-resolved Fabry–Pérot fringes in their optical reflection spectra due to thin-film interference. The fringes shift to higher wavelengths when the PS is exposed to vapors from organic solvents, as a result of an increase in the average refractive index of the PS layer. If a…
We dispersed electrochemical etched silicon into a colloid of ultrasmall ultrabright Si nanoparticles. Direct imaging using transmission electron microscopy shows particles of ∼1 nm in diameter, and infrared and electron photospectroscopy show that they are passivated with hydrogen. Under 350 nm excitation, the lumine…
Intense photoluminescence in highly disordered (amorphous) BaTiO3, PbTiO3, and SrTiO3 prepared by the polymeric precursor method was observed at room temperature. The emission band maxima from the three materials are in the visible region and depend on the exciting wavelength. The origin of the photoluminescence was n…
Optical mode crossing is not a plausible explanation for the new broad Brillouin doublet nor for the strong acoustic anomalies observed at low temperatures in SrTiO3. Data presented to support that explanation are also inconclusive.
The contact resistance between a carbon nanotube and metal electrodes decreases by several orders of magnitude and becomes long-term stable when the nanotube contacted by Ti-Au electrodes was annealed by a rapid thermal annealing method at 600-800 °C for 30 s. The contact resistances of the annealed samples are in the…
Thermodynamical fluctuations of temperature in mirrors of gravitational wave antennae may be transformed into additional noise not only through thermal expansion coefficient but also through temperature dependence of refraction index. The intensity of this noise is comparable with other known noises and must be taken…
In a one-dimensional periodic nonlinear $χ^{(2)}$ medium, by choosing a proper material and geometrical parameters of the structure, it is possible to obtain two matching conditions for simultaneous generation of second and third harmonics. This leads to new diversity of the processes of the resonant three-wave intera…
We study the thermodynamics of C incorporation on Si(100), a system where strain and chemical effects are both important. Our analysis is based on first-principles atomistic calculations to obtain the important lowest energy structures, and a classical effective Hamiltonian which is employed to represent the long-rang…
Uniform films of well-aligned carbon nanotubes have been grown using microwave plasma-enhanced chemical vapor deposition. It is shown that nanotubes can be grown on contoured surfaces and aligned in a direction always perpendicular to the local substrate surface. The alignment is primarily induced by the electrical se…
Field-induced strains of 6% are reported in ferromagnetic Ni–Mn–Ga martensites at room temperature. The strains are the result of twin boundary motion driven largely by the Zeeman energy difference across the twin boundary. The strain measured parallel to the applied magnetic field is negative in the sample/field geom…
We synthesized a series of amphiphiles with poly(ethylene glycol) [MW 2000 (PEG20), 5000 (PEG50), 12 500 (PEG125)] as a headgroup and one, two, or four palmitoyl chains (1C16, 2C16, or 4C16), using a lysine monodendron as a connector. The relationship between the hydrophilic−hydrophobic balance of the multiacyl PEG-li…
The effects of whey protein hydrolysis on film oxygen permeability (OP) and mechanical properties at several glycerol-plasticizer levels were studied. Both 5.5% and 10% degree of hydrolysis (DH) whey protein isolate (WPI) had significant effect (p </= 0.05) on film tensile properties compared to unhydrolyzed WPI. Hydr…
The primary component of the amyloid plaques in Alzheimer's disease (AD) is a highly ordered fibril composed of the 39−43 amino acid peptide, β-amyloid (Aβ). The presence of this fibril has been correlated with both the onset and severity of the disease. Using a combination of synthetic model peptides, solid-state NMR…
The observed anisotropies of surface vibrations for unreconstructed FCC metal (110) surfaces are often reversed from the "common sense" expectation. The source of these reversals is investigated by performing ab initio density functional theory calculations to obtain the surface force constant tensors for Ag(110), Cu(…
Ein in Wasser hergestellter heterogener Katalysator ist eindeutig sauberer und sollte zu saubereren Synthesen führen. In überkritischem Wasser wird La2CuO4 schneller gebildet und hat eine größere Oberfläche sowie eine höhere Aktivität bezüglich der Oxidation von CO als das entsprechende durch „traditionelle”︁ Keramiks…
Ein mikroporös/makroporöses Material konnte auf einfache Weise aus Kieselgur und einem siliciumreichen Zeolith hergestellt werden. Im Bild sind rasterelektronenmikroskopische Aufnahmen des Materials in zwei Vergrößerungen (links, Mitte) und die Anordnung der darauf ausgefällten Zeolithkristalle (rechts) gezeigt. Diese…
SBA-15 mesoporous silicates with surface functional groups were synthesized by cohydrolysis of tetraethoxyorthosilicate and ethyl-, carboxylate-, and ethylenediaminetriacetic acid-functionalized organosilanes (ETES, CTES, EDATAS, respectively) using the nonionic surfactant poly(ethylene oxide)−poly(propylene oxide)−po…
A heterogeneous catalyst prepared in water is, clearly, a cleaner one that leads to cleaner syntheses. La2CuO4 formed in supercritical water is produced more quickly, has a higher surface area, and a greater activity towards CO oxidation than the corresponding materials prepared by “traditional” ceramic synthesis. The…
Hexameric building blocks are found in a range of materials, such as hydrocarbons and water. Using water as a model compound, this Highlight identifies some of the important new results, from both the theoretical and experimental viewpoints, in the characterization of stable hexameric structures. The picture shows the…