Materials Literature
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Lead-free (K0.46−x∕2Na0.54−x∕2Lix)(Nb0.76Ta0.20Sb0.04)O3 piezoelectric ceramics were prepared by the conventional solid state sintering method without cold-isostatic pressing process. The x-ray diffraction and Raman scattering results show that the phase structure of the ceramics undergoes a transition from pseudocubi…
The optical properties of silicon quantum dots (QDs) embedded in a SiO 2 matrix are investigated at various temperatures using photoluminescence (PL) and time-resolved photoluminescence. Two broad luminescence bands, the S-band located at 600–850 nm and the F-band located at 450–600 nm, are observed. In the S-band a s…
We report the growth of hexagonal ZnO nanorods and nanoflowers on GaN-based LED epiwafer using a solution deposition method. We also discuss the mechanisms of epitaxial nucleation and of the growth of ZnO nanorods and nanoflowers. A GaN-based LED epiwafer was first deposited on a sapphire substrate by MOCVD with no el…
Polycrystalline sample of the title compound was prepared and its thermoelectric properties from 2to675K were investigated. This Zintl compound shows rather low thermal conductivity, 1.6Wm−1K−1, at room temperature. The value of its thermoelectric figure of merit ZT reaches 0.31 at 675K. Its electronic structure, calc…
The epitaxial relationship between wurtzite GaN and monoclinic β-Ga2O3 is studied by transmission electron microscopy. GaN is grown on β-Ga2O3 by molecular beam epitaxy without any low-temperature buffer layer, obtaining c plane GaN on a plane β-Ga2O3. The effect of the surface nitridation, which is necessary for the…
High frequency capabilities of carbon nanotube field-effect transistors (CNTFETs) are investigated. Structures with a large number of single-walled carbon nanotubes were fabricated using dielecrophoresis to increase the density of nanotubes in the device channel. The authors obtained an intrinsic current gain cutoff f…
A detailed analysis of the crystal structure in $R\mathrm{Ti}{\mathrm{O}}_{3}$ with $R=\mathrm{La}$, Nd, Sm, Gd, and Y reveals an intrinsic coupling between orbital degrees of freedom and the lattice which cannot be fully attributed to the structural deformation arising from bond-length mismatch. The $\mathrm{Ti}{\mat…
Enzymatic digestion is proposed as a method for concentrating gold nanoparticles produced in plants. The mild conditions of digestion are used in order to avoid an increase in the gold particle size, which would occur with a high-temperature process, so that material suitable for catalysis may be produced. Gold nanopa…
According to a recent proposal [S. Takayama et al., Appl. Phys. Lett. 87, 061107 (2005)], the triangular lattice of triangular air holes may allow to achieve a complete photonic band gap in two-dimensional photonic crystal slabs. In this work we present a systematic theoretical study of this photonic lattice in a high…
The exchange bias (EB) in LaMn_{0.7}Fe_{0.3}O_3 is observed by the negative shift and training effect of the hysteresis loops, while the sample was cooled in external magnetic field. The analysis of cooling field dependence of EB gives the size of the ferromagnetic (FM) cluster ~ 25 Angstrom, where the magnetic anisot…
The macromechanical properties of purely bundled in vitro actin networks are not only determined by the micromechanical properties of individual bundles but also by molecular unbinding events of the actin binding protein (ABP) fascin. Under high mechanical load the network elasticity depends on the forced unbinding of…
The relative merits of current-spin-density- and spin-density-functional theory are investigated for solids treated within the exact-exchange-only approximation. Spin-orbit splittings and orbital magnetic moments are determined at zero external magnetic field. We find that for magnetic (Fe, Co and Ni) and non-magnetic…
Two shakes: Double phase inversion of emulsions stabilized by a mixture of silica nanoparticles and a di-chain cationic surfactant can be induced by surfactant concentration alone. The picture shows emulsions of dodecane and water stabilized by silica nanoparticles (left, unstable), di-chain cationic surfactant (right…
In this letter the authors report the observation of double hysteresis loops in Cu-doped K0.5Na0.5NbO3 (KNN) ceramics. Unlike other ferroelectric titanates (e.g., BaTiO3), aging is not required for the ceramic to exhibit the double-loop-like characteristics. Based on the symmetry-conforming principle of point defects,…
Current induced precession states in spin-transfer devices are studied in the case of large easy plane anisotropy (present in most experimental setups). It is shown that the effective one-dimensional planar description provides a simple qualitative understanding of the emergence and evolution of such states. Switching…
The electronic reconstruction at the interface between two insulating oxides can give rise to a highly-conductive interface. In analogy to this remarkable interface-induced conductivity we show how, additionally, magnetism can be induced at the interface between the otherwise nonmagnetic insulating perovskites SrTiO3…
The effects of confining molecular hydrogen within carbon nanohorns are studied via high-resolution quasielastic and inelastic neutron spectroscopies. Both sets of data are remarkably different from those obtained in bulk samples in the liquid and crystalline states. At temperatures where bulk hydrogen is liquid, the…
First principle calculations based on LDA/GGA approximation for the exchange functional underestimate the position of the semi core 3d levels in GaX (X = N, P and As) semiconductors. A self-interaction correction scheme within the LDA+U/GGA+U approximation is found to be sufficient to correct this discrepancy. A conse…
In this study we present a new strategy for the theory-guided bottom up design of β-Ti alloys for biomedical applications using a quantum mechanical approach in conjunction with experiments. Parameter-free density functional theory calculations are used to provide theoretical guidance in selecting and optimizing Ti-ba…
Magnesium alloy has been implanted in rats to investigate the in vivo degradation behavior of magnesium for bone implant application. After 9 weeks postoperation, 100% implants were fixed and no inflammation was observed. Histological analysis showed new bone was formed around magnesium implant and no difference was f…