Materials Literature
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Phase diagrams for binary hard disc mixtures are predicted for diameter ratios between 0.15 and 1, using a new equation of state for the liquid based on recent calculations of the fifth virial coefficient, and a cell model for the solid. At diameter ratios close to 1, a substitutional solid solution is formed, and bot…
We made neutron powder diffraction measurements for phase III (at 4, 120, 180, 220, and 250 K) and phase II (at 280 K) of . The structure of phase III was determined by the Rietveld method using the data obtained at 4 K; the initial structure parameters were obtained by a systematic trial-and-error method. Phase III i…
A unique feature of the olfactory epithelium is its ability to give rise to new sensory neurons throughout life and also following injury. Cells at the basal side of the epithelium serve as neurogenic progenitor cells. The enzyme ecto-5'-nucleotidase is expressed at the surface of developing nerve cells and is regarde…
Epitaxially grown semiconductive Nb-doped BaTiO3 thin films with low electrical resistivity similar to that of the bulk single crystal were prepared by metal–organic chemical-vapor deposition. Thin films with 1.5–7.5 at. % Nb content showed n-type semiconductor character. The films with 5.7 at. % Nb content showed the…
A volume grating for outcoupling and line focusing of waveguided infrared light is designed and optimized. A local grating vector approach is used in combination with the rigorous coupled-wave analysis. By design, this volume grating coupler is holographically constructed on top of a waveguide by the interference of t…
A recombinant Escherichia coli strain XL1-Blue harboring a stable high-copy-number plasmid pSYL107 containing the Alcaligenes eutrophus polyhydroxyalkanoate biosynthesis genes and the Escherichia coli ftsZ gene was employed for the production of poly(3-hydroxybutyrate) (PHB) by fed-batch culture in a defined medium. S…
The total structure factors, S ( Q ), of pure molten and an equimolar mixture with , , were measured by neutron diffraction at 1013 K and 923 K, respectively. The results are generally consistent with the findings of previous MD simulations. The ion remains essentially unperturbed in the mixture. The real-space pair c…
Je mehrmeso-Substituenten vorhanden sind, desto verbogener sind die Porphyrine, die durch einfaches Umsetzen mit Alkylierungsreagentien wie Butyllithium, Hydrolysieren mit Wasser und Oxidieren mit 2,3-Dichlor-5,6-dicyan-1,4-benzochinon (DDQ) erhalten werden [Gl. (a)]. Nach dieser Methode lassen sich alle vier meso-Pos…
Apparently solvent-mediated and not through-bond photoinduced electron transfer (ET) takes place from the porphyrin (P) unit to the methylviologen (MV2+) unit in the rigid U-shaped molecules 1 (i.e., kTSET>kTBET; TS=through-solvent, TB=through-bond). The ratio of the rates of charge separation to charge recombination…
Stabilized by the tailor-made coordination in the crystal, B4 tetrahedra were characterized for the first time in a solid-state structure (shown on the right). Some of the Al atoms are replaced by B4 tetrahedra in the cubic τ-boride Ni20AlB14. The B–B distances of 1.681(15) Å are similar to those in the molecular stru…
An F−/Cl− ligand exchange in the stable organopalladium fluoro complex 1 generates naked fluoride ions in unusually high concentrations. The released F− readily fluorinates dichloromethane under exceedingly mild conditions and deprotonates chloroform to produce dichlorocarbene.
The resistance of polycrystalline doped LaMnO3 materials has been shown to be highly sensitive to low magnetic fields. To enable direct study of the properties of isolated grain boundaries we have grown epitaxial La0.7Sr0.3MnO3 films on a series of bicrystal substrates with different misorientation angles and patterne…
The thermoelectric properties (resistivity and thermopower) of single crystals of the low dimensional pentatelluride materials, HfTe5 and ZrTe5, have been measured as a function of temperature from 10 K<T<320 K. The effect of small amounts of Ti substitutional doping (M1−xTixTe5, where M=Hf, Zr) on the t…
45 \AA{} diameter dodecanethiol capped gold nanocrystals self-organize during solvent evaporation on a carbon substrate, with the final thickness of the nanocrystal film depending on solvent polarity. A quantitative model for the film thickness is presented, showing the film structure (thickness) to depend on the bala…
The molecular dynamics of glass-forming liquids is strongly affected by nm-scale confinements. Our dielectric data provide strong evidence both for the ``cooperativity'' concept and for the existence of two states (interfacial layer and volume liquid). With decreasing size of confinement the orientational relaxation a…
Despite their larger separation, the porphyrin groups in 1 are more strongly conjugated than in analogous compounds in which butadiyne is the bridging unit. This stronger electronic coupling in 1 results in a bathochromic shift in its absorption and emission spectra.
Boron nitride nanotubes (BN-NTs) were synthesized by using excimer laser ablation at 1200 °C in different carrier gases. The main characteristic of the BN-NTs produced by this method is that nanotubes are of only one to three atomic layers thick, which could be attributed to the dominance of the axial growth rate over…
We show that the method used by Ogut, Chelikowsky and Louie (Phys. Rev. Lett. 79, 1770 (1997)) to calculate the optical gap of Si nanocrystals omits an electron-hole polarization energy. When this contribution is taken into account, the corrected optical gap is in excellent agreement with semi-empirical pseudopotentia…
Mechanically induced degradation of diamond, as occurs during polishing, is studied using total-energy pseudopotential calculations. The strong asymmetry in the rate of polishing between different directions on the diamond (110) surface is explained in terms of an atomistic mechanism for nanogroove formation. The post…
The structure of the skutterudite ${\mathrm{CoSb}}_{3}$ contains two large empty cages, or voids, per unit cell. Compounds obtained by filling these cages with rare earth atoms possess an enhanced thermoelectric figure of merit. Control of the electronic and thermal transport properties of these materials can be achie…