Materials Literature
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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…
ZnO tubes were epitaxially grown on sapphire (0001) substrates by metalorganic chemical vapor deposition. The tubes grew along the substrate normal and were characterized by hexagon-shaped cross sections. All of the tubes possessed the same epitaxial relationships with respect to the substrate. Both reactor pressure a…
A general theory for the core-level electron excitation of anisotropic systems using angular integrated electron energy-loss spectroscopy has been derived. We show that it is possible to define a magic angle condition at which the specimen orientation has no effect on the electron energy-loss spectra. We have not only…
In specular reflection experiments the reflected beam from the end side of thick substrates is typically neglected. This is equivalent to assuming the substrates as semi-infinite matter. However, it is known that we should also consider the reflected beam from the end sides. Here we have investigated the effect of thi…
A meso,meso-linked porphyrin trimer, (ZnP)3, as a light-harvesting chromophore, has been incorporated for the first time into a photosynthetic multistep electron-transfer model including ferrocene (Fc) as an electron donor and fullerene (C60) as an electron acceptor, to construct the ferrocene-meso,meso-linked porphyr…
The thermal conductivity at 300 K of (10,10) carbon nanotubes that have been functionalized by chemical attachment of phenyl rings through covalent bonding (chemisorption) at random positions has been calculated as a function of adsorption density using classical trajectories. The system exhibits a rapid drop in therm…
Under the right circumstances, colloidal particles can exhibit the same behavior as atoms or molecules. In his Perspective, Poon discusses the report in the same issue by Aarts et al. on their studies of colloid-polymer mixtures that simulate the interface between a liquid and a vapor. Thermal energy naturally excites…