Materials Literature
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We consider a 1D lattice gas model in which the atoms interact via an infinite number of cluster interactions within contiguous atomic chains plus the next nearest neighbor pairwise interaction. All interactions are of arbitrary strength. An analytical expression for the size distribution of atomic chain lengths is ob…
We present an ab initio theoretical formalism for the static paramagnetic spin susceptibility of metals at finite temperatures. Since relativistic effects, e.g. spin-orbit coupling, are included, we can identify the anisotropy or easy axes of the spin fluctuations. Our calculations find hcp-iron to be unstable to in a…
Recent investigations of grain growth in nanocrystalline materials have revealed a new growth mechanism: grain-rotation-induced grain coalescence. Based on a simple model employing a stochastic theory and using computer simulations, here we investigate the coarsening of a polycrystalline microstructure due solely to t…
The refractive indices of 509 oxides and 55 fluorides were analyzed using two forms of a one-term Sellmeier equation: (1) 1/(n2−1)=−A/λ2+B, where A, the slope of the plot of (n2−1)−1 versus λ−2 in units of 10−16 m2, gives a measure of dispersion and B, the intercept of the plot at λ=∞, gives n∞=(1+1/B)1/2 and (2) n2−1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical Strategies To Design Textured Materials: from Microporous and Mesoporous Oxides to Nanonetworks and Hierarchical StructuresGalo J. de A. A. Soler-Illia, Clément Sanchez, Bénédicte Lebeau, and Joël PatarinView Author Information Laboratoire de Chimie de la Matière Co…
Two visible luminescence bands are observed in Re4+:Cs2ZrBr6 under NIR excitation at temperatures between 10 and 300 K. We perform absorption, luminescence, excitation, and time resolved spectroscopic studies at various temperatures to characterize this upconversion luminescence and its driving mechanism. From the tim…
A structural model of the antiphase boundaries (APBs) induced by phase transition in perovskite and layered perovskite oxides is put forward. Besides the distortion of oxygen octahedra, the existence of two types of ion with different sizes on A sites in perovskite blocks and their ordering in local areas might be the…
In this experiment we have measured the temperature dependence of field emission characteristics for boron-doped diamond and diamond-like films at various temperatures and low fields. The threshold voltage increases and emission current density decreases as the temperature decreases. These field emission characteristi…
Two genes bearing similarity to alternative sigma factors were identified in the Deinococcus radiodurans genome sequence and designated sig1 and sig2. These genes were cloned and inactivated, and both were found to be important for survival during heat and ethanol stress, although the sig1 mutants displayed a more sev…
High-quality interface between an insulator and ZnO as a wide-band-gap semiconductor should realize devices based on field-effect carrier modulation or superlattices having large band offset over 1 eV. We demonstrate that LiGaO2 could be a possible candidate for this purpose. Heteroepitaxy of LiGaO2 is demonstrated on…
Using a recently developed image representation for Stokes flow in a half-space bounded by a planar wall [Cichocki and Jones, Physica A 258, 273 (1998)], the image system is constructed for the flow field produced by a force multipole in the space bounded by two parallel walls. The image singularities are expressed in…
Mesoporous silica nanostructures have been synthesized and loaded with Pd and Pt catalytic noble metals. It is found that Pd forms small nanoclusters (3–5 nm) on the surface of the mesoporous structure whereas Pt impregnation results in the inclusion of Pt nanostructures within the silica hexagonal pores (from nanoclu…
Nonlinear elastic properties of single-wall carbon nanotubes subjected to large-scale tensile deformation were investigated using the second-generation Brenner potential. The energy change of the nanotubes was found to be a cubic function of tensile strains. In contrast to values of in-plane stiffness C based on small…
A surfactant-assisted synthesis method was applied to prepare nanosized ceria particles used as the three-way catalyst supports. The Rietveld refinements of crystalline structures of ceria calcined at various temperatures, together with XRD, FTIR, and TGA techniques, confirm that the surfactant cations are incorporate…
Conventional lithographic exposure is used to selectively degrade regions of a self-assembled diblock copolymer film to obtain a honeycomblike nanoporous array template with arbitrary lateral design. Combined with other lithographic process steps, this enables the fabrication of arrays of nanostructures interfaced to…
The evolution of sheet resistance of n-type single-crystal wurtzite ZnO epilayers exposed to bombardment with MeV H1, Li7, O16, and Si28 ions at room temperature is studied in situ. We demonstrate that sheet resistance of ZnO can be increased by about 7 orders of magnitude as a result of ion irradiation. Due to extrem…
The field emission properties of “porous diamond-like” carbon structures have been characterized. A hot filament chemical vapor deposition system fed with ethyl alcohol vapor diluted in helium was used to deposit the samples. Morphological analysis by field emission scanning electron microscopy revealed that they had…
Sulfur incorporated nanocrystalline carbon (n-C:S) thin films were grown on molybdenum substrates by a hot-filament chemical vapor deposition technique using gas mixtures of methane, hydrogen, and a range of hydrogen sulfide (H2S) concentrations (100–500 ppm with an interval of 100 ppm) at a fixed substrate temperatur…
We studied polarization switching of 295 nm thick 〈111〉-oriented-Pb(Zr0.45Ti0.55)O3 (PZT) thin-film capacitors through a polarization hysteresis loop and piezoelectric force microscopy (PFM) on top of the Pt electrode. Positive voltage pulses of 450 kV/cm and 2.5 ms were applied to the top as a poling pulse. Negative…
We report the discovery of a large magnetic entropy change in La1.4Ca1.6Mn2O7, a bilayered perovskite manganese oxide that has a Curie temperature (TC) of about 270 K and which allows magnetic refrigeration at room temperature. The magnetic entropy changes reach values of 11.3 J K−1 kg−1 and 16.8 J K−1 kg−1 for field…