Materials Literature
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Abstract Electronic absorption, magnetic circular dichroism (MCD), IR spectra, and cyclic and differential pulse voltammograms of metal‐free and copper monoaza‐ and opposite diazaporphyrins are reported, together with molecular orbital (MO) calculations using the density functional theory (DFT) method. Introduction of…
We report results of integrated study of resistivity, magnetoresistance, Hall effect, thermopower, and magnetothermopower in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ single crystals with $x=0.15,0.20,0.25.$ The focus is on the vicinity of the Curie temperature. It is shown that near ${T}_{…
The 295Pt and 205Tl NMR chemical shifts of the complexes [(NC)5Pt-Tl(CN)n]n- n=0-3, and of the related system [(NC)5Pt--Tl--Pt(CN)5]3- have been computationally investigated. It is demonstrated that based on relativistically optimized geometries, by applying an explicit first solvation shell, an additional implicit so…
Abstract Die Pyrrol‐Aldehyd‐Cyclokondensation gilt seit über einem halben Jahrhundert als die klassische Eintopfsynthese symmetrischer Porphyrine, lieferte aber auch viele nichtporphyrinartige Makrocyclen wie “N‐invertierte” Porphyrine, Corrole, Sapphyrine und expandierte Porphyrine. Sie erwies sich somit als vielseit…
A silica-supported, lowly loaded vanadium oxide (V2O5/SiO2) photocatalyst promotes the photocatalytic epoxidation of propene with O2 at steady state in a flow reactor system. Very little deep oxidation of propene into CO2 takes place over V2O5/SiO2, in contrast to the results obtained over a TiO2 photocatalyst in whic…
Helicale selbstorganisierte Säulen bilden supramolekulare chirale kubische und columnare flüssigkristalline Phasen (siehe Bild). Wasserstoffverbrückte Scheiben aus Folsäurederivaten, mit Oligo(glutaminsäure)-Domänen und lipophilen Alkylketten, ergeben durch Komplexierung mit nichtchiralen Ionen selbstorganisierte chir…
Spider silk is made and spun in a complex process that tightly controls the conversion from soluble protein to insoluble fiber. The mechanical properties of the silk fiber are modulated to suit the needs of the spider by various factors in the animal's spinning process. In the major ampullate (MA) gland, the silk prot…
Abstract Air‐formed oxide on a CuAl 2 model alloy is shown to be free of copper species, with copper enriching in the alloy. With thickening of the oxide by anodizing, copper enriches further to a critical concentration at which its oxidation proceeds with incorporation of Cu(II) species into the film. Such species mi…
Abstract Angle‐resolved XPS data (elemental quantification and high‐energy‐resolution C 1s) are presented for ten polymers with side‐chains of the form OCO(CF 2 ) y F, COO(CH 2 ) 2 OCO(CF 2 ) y F ( y = 1, 2, 3) and COO(CH 2 ) x (CF 2 ) y F ( x = 1, y = 1, 2, 3; x = 2, y = 8). Particular attention was paid to charge…
A hysteresis model based on the Jiles-Atherton theory is incorporated into a power transformer model in an electromagnetic transient program (EMTP)-type program. The eddy current effects are also included in the same model. Comparisons are made between recorded and simulated waveforms using a single-phase distribution…
A suggestion for substitutional Si doping in single-wall carbon nanotubes (SWNTs) through radial tube deformation is presented. Although the doping of buckyballs with substitutional Si atoms has been experimentally achieved, so far the synthesis of silicon-doped SWNT has not been reported. Using theoretical methods ba…
Abstract Sheet-like Bi2Fe4O9 nanoparticles were successfully synthesized by a rather facile hydrothermal process. Transmission electron microscopic (TEM) and selected area electron diffraction (SAED) studies show that the particles are sheet-like, about 30 nm in the direction of thickness. X-ray diffraction (XRD) anal…
The crystal and electronic structures of the entire series of alkali aluminum and alkali gallium tetrahydrides (ABH 4; A = Li, Na, K, Rb, or Cs; B = Al or Ga) are systematically investigated using an ab initio projected augmented plane-wave method. For structural stability studies, we have considered several possible…
Calcite crystals were nucleated and grown from supersaturated aqueous solutions in the presence of variable concentrations of lithium. The diagram of supersaturation vs [Li + ]/[Ca 2+ ] concentration ratio (“morphodrome”) shows a continuous habit variation, from the dominant {011̄1} rhombohedron (at low [Li + ]/[Ca 2+…
Directed catalyst evolution: IR-thermography and combinatorial library design (doping and composition spread) lead in a few generations to new, noble-metal-free catalysts for the low-temperature oxidation of CO in air. The picture shows the emissivity-corrected IR thermographic image of a catalyst library; the red dot…
We report the identification of the vacancy-hydrogen complex in single crystal diamond synthesized by chemical vapor deposition. The S=1 defect is observed by electron paramagnetic resonance in the negative charge state. The hydrogen atom is bonded to one of the carbon atoms neighboring the vacancy. Unlike the analogo…
Two new neutral thioantimonates(III) were first prepared by the reaction of elemental manganese, antimony, and sulfur in tren (tren = tris(2-aminoethyl)amine, C6H18N4) at 140 degrees C. In the amine-rich compound [Mn(tren)]2Sb2S5 (1) the trigonal SbS3 pyramids are connected via common corners (S(3)) into the tetradent…
We report room temperature angle-resolved photoemission experiments on $1T\ensuremath{-}{\mathrm{TaS}}_{2}$ and $1T\ensuremath{-}{\mathrm{TaSe}}_{2}$ complemented by density-functional theory calculations. Fermi-surface mapping experiments in the charge-density wave (CDW) phase are similar for the two compounds and do…
Abstract The deposition of Ce‐based conversion coatings onto 2024‐T3 Al alloy sheet was studied using Rutherford backscattering spectroscopy, scanning electron microscopy, Auger electron spectroscopy, x‐ray photoelectron spectroscopy and atomic force microscopy. The Al sheet was pretreated with an alkaline clean follo…
Stable polar oxide surfaces must be simultaneously electrostatically compensated and in thermodynamic equilibrium with the environment. As a paradigm, the MgO(111)-p(2x2) reconstructed surface is shown to involve combinations of Mg-covered terminations with peculiar insulating electronic structure, favored in O-poor c…