Materials Literature
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The transcription factor Rex has been implicated in regulation of the expression of genes important for fermentative growth and for growth under conditions of low oxygen tension in several Gram-positive bacteria. Rex senses the redox poise of the cell through changes in the NADH/NAD(+) ratio. The crystal structures of…
This second paper in a series describes the relationship between grain growth kinetics and grain boundary complexions in silica‐doped alumina. Dense high‐purity silica‐doped alumina samples were annealed for various times in the temperature range of 1300° and 1900°C and their grain growth behavior was quantified. Four…
Near band-gap luminescence (hν⩾5eV) of hexagonal boron nitride has been studied by means of the time- and energy-resolved photoluminescence spectroscopy method. Two emissions have been observed at 5.5 and 5.3eV. The high-energy emission at 5.5eV is composed of fixed subbands assigned to bound excitons at 5.47, 5.56, a…
The size-effect problem in metal-ferroelectric-metal heterostructures is analyzed in terms of the multiscale scheme---which combines phenomenology and first-principles calculations---recently developed by the authors. We demonstrate how this effect can be separated into two distinct contributions: a long-range electro…
Hydrogen atoms play key roles in enzyme mechanism, but as this study shows, even high-quality X-ray data to a resolution of 1 A cannot directly visualize them. Neutron diffraction, however, can locate deuterium atoms even at resolutions around 2 A. Both neutron and X-ray diffraction data have been used to investigate…
The cytotoxicity of single-walled carbon nanotubes (SWCNTs) suspended in various surfactants was investigated by phase contrast light microscopy characterization in combination with an absorbance spectroscopy cytotoxicity analysis. Our data indicate that individual SWCNTs suspended in the surfactants, sodium dodecyl s…
The contribution of the fundamental gap E_ as well as those of the E_ + Delta(so) and E+ transitions to the dielectric function of GaAs1-xNx alloys near the band edge were determined from variable-angle spectroscopic ellipsometry and modulated photoreflectance spectroscopy analyses. The oscillator strength of the E_ o…
The evolution of self-assembled structures of polymer-terminated gold nanorods in ternary solvent mixtures is governed by the competition of the side-by-side and end-to-end association modes of the nanorods. This competition arises from the different solubilities of the blocks in the solvent mixture. The effects of so…
The orthorhombic SrIrO3 perovskite was synthesized under 5GPa and 1000°C. It is paramagnetic below about 170K and transfers to an unknown magnetism under higher temperature. A band type metal to insulator transition caused by a pseudogap was observed at about 44K. Interestingly a positive magnetoresistance, i.e., resi…
A solution growth approach for zinc oxide (ZnO) nanowires is highly appealing because of the low growth temperature and possibility for large area synthesis. Reported reaction times for ZnO nanowire synthesis, however, are long, spanning from several hours to days. In this work, we report on the rapid synthesis of ZnO…
The dispersive interaction between nanotubes is investigated through ab initio theory calculations and in an analytical approximation. A van der Waals density functional (vdW-DF) [M. Dion et al., Phys. Rev. Lett. 92, 246401 (2004)] is used to determine and compare the binding of a pair of nanotubes as well as in a nan…
We report a first-principles calculation that models the effect of iron (Fe) atoms on the adsorption of a tungsten (W) atom on W(100) surfaces. The adsorption of a W atom on a clean W(100) surface is compared to that of a W atom on a W(100) surface covered with a monolayer of Fe atoms. The total energy of the system i…
The use of lead-free materials has recently become a very important issue in environmental protection of the earth. Two groups of lead-free ceramics, (K0.5,Na0.5)NbO3 based (KNN) and Bi1−y(NaxK1−x)yTiO3 based (BNKT), were studied for their thermal, dielectric, and pyroelectric properties as candidates for pyroelectric…
Synthesis of hyperbranched poly(1,2,3-triazole)s ( hb -PTAs) has been a challenge: the AB 2 monomers were inclined to self-oligomerize, and their Cu(I)-catalyzed click polymerizations failed to yield soluble polymers. We tackled the challenge in this work and succeeded in generating hb -PTAs with regioregularity, proc…
Commercially available gases contain residual impurities leading to a background oxygen partial pressure of typically several 10^{-6} bar, independent of temperature. This oxygen partial pressure is inappropriate for the growth of some single crystals where the desired oxidation state possesses a narrow stability fiel…
The microstructure of a CoNiAl FSMA was determined by conventional transmission electron microscopy, electron diffraction studies together with advanced microscopy techniques and in-situ Lorentz microscopy. 10 to 60 nm sized rod-like precipitates of hcp $ε$-Co were confirmed to be present by HRTEM. The orientation rel…
We introduce a method for the formation of block copolymer micelles through interfacial instabilities of emulsion droplets. Amphiphilic polystyrene-block-poly(ethylene oxide) (PS-PEO) copolymers are first dissolved in chloroform; this solution is then emulsified in water and chloroform is extracted by evaporation. As…
The description of realistic strongly correlated systems has recently advanced through the combination of density functional theory in the local density approximation (LDA) and dynamical mean field theory (DMFT). This $\text{LDA}+\text{DMFT}$ method is able to treat both strongly correlated insulators and metals. Seve…
We study the effects of quenched height fluctuations (ripples) in graphene on the density of states (DOS). We show that at strong ripple disorder, a divergence in the DOS can lead to an ordered ground state. We also discuss the formation of dislocations in corrugated systems, buckling effects in suspended samples, and…
Epitaxial oxide thin films are at the heart of new “oxide electronic” applications, such as excitonic ultraviolet light-emitting diodes and resistive switching memories. Complex oxide films are often grown by pulsed laser deposition (PLD) because the technique is believed to be material agnostic. Here, we show that on…