Materials Literature
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We report a new surface micromachining technology to fabricate monocrystalline silicon membranes covering a vacuum cavity for applications like piezoresistive pressure sensors. The main process steps are: (i) local anodic etching of layered porous silicon with different porosities, (ii) thermal rearrangement of the po…
The effect of aniline hydrochloride (AHC) on the size and shape of sodium dodecyl sulfate (SDS) micelles has been investigated by dynamic light scattering. A monotonic decrease in the diffusion coefficient of the micelles was observed with an increase in AHC at fixed SDS concentration. This was ascribed to prolate ell…
Effect of Co doping on leakage current has been investigated in capacitor consisting of Ba0.5Sr0.5Ti1−xCoxO3 (BSTC, x=0, 0.002, 0.010) thin film, Pt top electrode, and Nb-doped SrTiO3 (STON) bottom electrode. Co doping remarkably decreases the leakage current in BSTC thin film, such as from 9×10−7 A in undoped thin fi…
The microscopic origin of the spin Hamiltonian (SH) parameters for Ni2+(3d8) ions in a trigonal type I symmetry (C3v,D3d,D3) crystal field (CF) is studied. In addition to the spin–orbit (SO) interaction, we consider also the spin–spin (SS) and spin–other-orbit (SOO) interactions. The relative importance of the four (S…
The thermal stability of electrically conducting SrRuO3 thin films grown by pulsed-laser deposition on (001) SrTiO3 substrates has been investigated by atomic force microscopy and reflection high-energy electron diffraction (RHEED) under reducing conditions (25–800 °C in 10−7–10−2 Torr O2). The as-grown SrRuO3 epitaxi…
A polymer-dispersed liquid crystal confined in a 90° twisted cell (T-PDLC) is demonstrated. In comparison to a conventional PDLC, the T-PDLC is also polarization independent while exhibiting a higher contrast ratio. Potential applications of the T-PDLC are in polarizer-free reflective display and light switch. A black…
We have identified a Mn-rich layer on the surface on (Ga,Mn)As thin films which significantly influences soft x-ray absorption measurements. The Mn L3,2 x-ray absorption spectra of the untreated films show a strong multiplet structure, consistent with earlier observations and characteristic of MnO. After removal of th…
Classical shell-model potentials for describing the complex ferroelectric behaviour of barium titanate and strontium titanate are developed and used to simulate Ba x Sr 1− x TiO 3 solid solutions. The temperature versus composition phase diagram is very well described and the local behaviour of the structure and polar…
We report four-probe I–V measurements on individual vertically aligned carbon nanofibers (VACNFs). These measurements were enabled by the fabrication of multiple Ti/Au ohmic contacts on individual fibers that exhibited resistance of only a few kilohms. These measurements demonstrate that VACNFs exhibit linear I–V beha…
The largest organometallic cluster compound consisting of Al, C, and H only (Al50Cp, Cp*=C5Me5) is a fascinatingly simple structure of comparably high symmetry (see structure). The pentamethylcyclopentadienyl ligands form a carbon shell similar to the arrangement found in fullerene structures.
A series of hierarchically ordered porous silica composites were synthesized using anionic (SO 4 - 2 ) polystyrene spheres and triblock copolymers Pluronic F127 (EO 107 PO 70 EO 107 ) and P123 (EO 20 PO 70 EO 20 ) as templates in the presence of cosurfactants ( n -alcohols) in an acidic medium. The silica materials we…
UNLABELLED: TargetDB is a centralized target registration database that includes protein target data from the NIH structural genomics centers and a number of international sites. TargetDB, which is hosted by the Protein Data Bank (RCSB PDB), provides status information on target sequences and tracks their progress thr…
We propose that the dynamics of supercooled liquids and the formation of glasses can be understood from the existence of a zero-temperature dynamical critical point. To support our proposal, we derive a dynamic field theory for a generic kinetically constrained model, which we expect to describe the dynamics of a supe…
Abstract Molecular structure dependences of the coefficients of molecular packing ( K p ) and the intrinsic birefringence (Δ n 0 ) were investigated for aromatic polyimides (PIs) using a method based on the modified Lorentz–Lorenz equation and the Vuks equation. This method needs only average refractive indices and po…
We study the Voronoi and void statistics of super-homogeneous (or hyperuniform) point patterns in which the infinite-wavelength density fluctuations vanish. Super-homogeneous or hyperuniform point patterns arise in one-component plasmas, primordial density fluctuations in the Universe, and in jammed hard-particle pack…
Synthesis and characterization of Nanocrystalline long persistent SrAl2O4:Eu2+, Dy3+ phosphor via a modified combustion process has been presented in the paper. In this synthesis process, a mixture of respective metal nitrates, flux and combustible agent (urea/camphor) were thermally treated with slight modification a…
Quantum-confinement effects in the conduction band of deposited germanium nanocrystals are measured to be greater than in similar-sized silicon nanocrystals. The germanium particles are condensed out of the gas phase and their electronic properties are determined with x-ray absorption spectroscopy. The conduction band…
We have investigated metallic break junctions of the heavy-fermion compound UPd2Al3 at low temperatures between 0.1K and 9K and in magnetic fields up to 8T. Both the current-voltage I(V) characteristics and the dV/dI (V) spectra clearly showed the superconducting ($T_{\rm c}\simeq$ 1.8K) as well as the antiferromagnet…
Using atomistic pseudopotential and configuration-interaction many-body calculations, we predict a metal-nonmetal transition and an excitonic ground state in the InAs/InSb quantum dot (QD) system. For large dots, the conduction band minimum of the InAs dot lies below the valence band maximum of the InSb matrix. Due to…
We performed x-ray diffraction studies on a series of (1−x)Pb(Zn1/3Nb2/3)O3−xPbTiO3 single crystals with different incident photon energies, and therefore different penetration depths. Our results show that outer layers of ∼10–50 μm thick are present in all samples. The structure of those outer layers is different fro…