Materials Literature
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The food packaging material is expected to provide optimum protective properties so that the product it encloses remains in satisfactory condition for its anticipated shelf life. The packaging tech...
The thermal stability of nanometer-sized Cu particles on a 400–500 nm thick SiO2 layer on top of a Si(100) substrate was studied after annealing in ultrahigh vacuum up to 620 °C. Atomic force microscopy, low-energy ion scattering, Rutherford backscattering spectrometry, and Auger electron spectroscopy measurements cle…
Low-resistivity (ρ) and highly transparent pure indium oxide (In2O3) thin films grown on glass substrates by pulsed laser deposition at substrate temperature (Ts) between room temperature and 200 °C are reported. As-deposited films with resistivity (ρ) of ∼3×10−4 Ω cm and transmittance (visible), above 87% were obtain…
Toroidal mesostructured molybdenum bronzes and blues (shown schematically) have been synthesized. The effect of phase changes on the electrical conductivity of these materials is explored in depth. A unique shape-evolution reaction is also discussed.
Das kristalline, spinlose π-Dimer (1.+⋅PF6)2 erhält man bei der Oxidation des Bipyrrols 1 mit Ferroceniumhexafluorophosphat. Die elektrochemisch in Lösung nachgewiesene diamagnetische Spezies wurde NMR-spektroskopisch als σ-Dimer identifiziert.
The ferroelectric properties of Pb(Zr,Ti)O3 films are known to degrade when subjected to forming gas anneals. In an earlier publication we established that although there may be loss of oxygen and lead during forming gas anneal, the primary mechanism for loss of ferroelectricity is the incorporation of hydrogen and su…
Synthetic approaches to a variety of substituted glycoluril compounds are presented herein. We have applied several of these compounds in the solution-phase synthesis of combinatorial libraries, and we have developed methods to differentiate individual reaction sites for the stepwise synthesis of individual polyfuncti…
Durch den Einbau von miteinander wechselwirkenden Laserfarbstoffen an den Kettenenden und im Brennpunkt eines dendritischen Makromoleküls kann Energie unterschiedlicher Wellenlängen, die durch die große periphere Antenne des Dendrimers gesammelt wurde (siehe linkes Bild), direkt und mit hohem Wirkungsgrad auf den zent…
Band structure calculations from first principles provide the basis of a simple explanation for the appearance of ferromagnetism in iron, cobalt, and nickel that is founded upon a uniquely chemical concept: bonding. It is shown that the onset of ferromagnetism strengthens the metal-metal bonds in these transition meta…
The crystalline, spinless π dimer (1.+⋅PF6)2 was obtained by the oxidation of bipyrrole 1 with ferrocenium hexafluorophosphate. The diamagnetic species generated electrochemically in solution was identified as the σ dimer by NMR spectroscopy.
Sintering, structural correlations and mechanical behavior of nanophase silica glasses are investigated using large-scale, parallel molecular-dynamics simulations. During the sintering process, the pore sizes and distribution change without any discernible change in the pore morphology. The height and position of the…
The influence of post-sintering annealing on the dielectric relaxation behavior was studied in (Sr1−1.5xLax)TiO3 in the temperature range of 1.5–300 K. The results show that the dielectric permittivity peaks with frequency dispersion can be gradually and absolutely eliminated by annealing in an oxidizing atmosphere, a…
Length-dependent charge redistribution in dangling-bond (DB) linear chains fabricated on a hydrogen-terminated $\mathrm{Si}(100)\ensuremath{-}(2\ifmmode\times\else\texttimes\fi{}1)$ surface is analyzed by using scanning tunneling microscopy and first-principles calculations. The second-layer Si atoms are displaced alt…
Die lösungsmittel- und katalysatorfreie Kondensation von Pyrrol und Aldehyden bietet einen äußerst einfachen Zugang zu neuartigen Corrolen [Gl. (1); Ar = C6F5, 2,6-F2C6H3, 2,6-Cl2C6H3]. Das Pentafluorphenyl-substituierte Produkt (Ar = C6F5) ist eine exzellente Vorstufe für andere Derivate, einschließlich eines ionisch…
A three-dimensional network with one-dimensional channels (see picture) has been self-assembled from the nickel(II) complex of cyclam and 1,3,5-benzenetricarboxylate in water through hydrogen-bond formation. The channels have an appropriate diameter (10.3 Å) to include D-glucose with a formation constant of Kf=(1.38±0…
Addition of Nd, Tb, or Dy to amorphous Ti–O thin films is found to improve the dielectric properties of the films. Specifically, substitution of 10–30 at. % of the dopant for Ti is found to dramatically decrease the leakage current, increase the breakdown voltage, and yet retain the relatively high dielectric constant…
It is completely plausible that unmodified materials of natural origin, such as the native macromolecules cellulose or starch, are biodegradable. If these materials are modified then degradation may, depending on the degree of modification, be more difficult or even impossible. In the same manner synthesized macromole…
The thermal stability and relaxation processes in hydrogen free diamond-like-carbon films with different sp3 fractions (40%, 60%, and 80%) are comparatively studied for the first time by visible Raman spectroscopy. The 80% sp3 film is very stable under annealing in the entire temperature region investigated (300–1270…
The formation of boron nitride (BN) nanotubes via a solid-state process is demonstrated. The nanotubes are produced by first ball-milling hexagonal BN powder to generate highly disordered or amorphous nanostructures, followed by annealing at temperatures up to 1300 °C. The annealing leads to the nucleation and growth…
Porous alumina membranes with ordered pore arrays were prepared electrochemically from Al metal in C2H2O4 or H2SO4. Photoluminescence (PL) measurements show that a blue PL band occurs in the wavelength range of 400–600 nm. This band originates from singly ionized oxygen vacancies (F+ centers) in porous alumina membran…