Materials Literature
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Novel proton-conducting gels have been prepared by entrapping heteropolyacids solutions in polar aprotic solvents within the polymer matrix. The influence of the type of solvent, polymer matrix, and acid concentration on the conductivity, mechanical properties, and thermal stability has been examined. Poly(methyl meth…
Electrogenerated polymers based on the nickel(II) complex 2,3-dimethyl-N,N'-bis(salicylidene)butane-2,3-diaminatonickel(II), poly[Ni(saltMe)], were characterised by in situ FTIR and UV/Vis spectroscopy and ex-situ EPR spectroscopy in order to gain insights into film structure, electronic states and charge conduction.…
The synthesis of the layered double hydroxide (LDH) [Zn−Cr−Cl], well-known for its ability to be synthesized only with the ratio Zn:Cr = 2:1, has been followed by UV−visible and extended X-ray absorption fine structure (EXAFS) spectroscopy in order to understand the mechanisms of its formation. The UV−visible spectrum…
Three new one-dimensional nickel(II) complexes with the formulas trans-[Ni(N-Eten)2(mu1.3-N3)]n(ClO4)n (1), trans-[Ni(N-Eten)2(mu1.3-N3)]n(PF6)n (2), and cis-[Ni(N-Eten)(mu1.1-N3)2]n (3) (N-Eten = N-Ethylethylenediamine) were synthesized and characterized. Complex 1 has the P2(1)/c space group and consists of a struct…
Based on a previously discovered method for amine oxidations using flavins as catalysts and hydrogen peroxide as oxidant, a comparative kinetic study using NMR spectroscopy was undertaken with a series of flavins for amine and thioether oxidations. Included in this series is the newly prepared 7,8-difluoro-1,3-dimethy…
The homoleptic rare-earth pyrazolate complexes [Sc(tBu2pz)3], [Ln2(tBu2pz)6] (Ln = La, Nd, Sm, Lu), [Eu4(tBu2pz)8] and the mixed oxidation state species [Yb2(tBu2pz)5] (tBu2pz = 3,5-di-tert-butylpyrazolate) have been prepared by a simple reaction between the corresponding rare-earth metal and 3,5-di-tert-butylpyrazole…
BaTiO 3 and anatase with platelike particle morphology were prepared by using a hydrothermal soft chemical process. A layered titanate of K 0.8 Ti 1.73 Li 0.27 O 4 with a lepidocrocite-like layered structure, which has a platelike particle morphology, was used as a precursor. In the first step, the layered titanate wa…
Unser gestiegenes Verständnis der Struktur-Eigenschafts-Beziehungen einiger ausgewählter Biomakromoleküle hat – zusammen mit unseren verbesserten Fertigkeiten, Makromoleküle mit einer strukturellen Genauigkeit, die der der Proteine nahekommt, herzustellen – den Horizont zu einem neuen Forschungsbereich geöffnet, der d…
We analytically study the photorefractive Gunn effect in n-GaAs subjected to two external laser beams which form a moving interference pattern (MIP) in the semiconductor. When the intensity of the spatially independent part of the MIP, denoted by $I_0$, is small, the system has a periodic domain train (PDT), consisten…
Numerical studies of amorphous silicon in harmonic approximation show that the highest 3.5% of vibrational normal modes are localized. As vibrational frequency increases through the boundary separating localized from delocalized modes, near omega_c=70meV, (the "mobility edge") there is a localization-delocalization (L…
The complex Ni[S2C2(CF3)2]2 reacts with light olefins, including ethylene and propylene, selectively and reversibly. The reaction is not poisoned by hydrogen gas, carbon monoxide, acetylene, or hydrogen sulfide, which are commonly present in olefin streams, presumably because olefin binding occurs through the sulfur l…
Intramolecular junctions in single-walled carbon nanotubes are potentially ideal structures for building robust, molecular-scale electronics but have only been studied theoretically at the atomic level. Scanning tunneling microscopy was used to determine the atomic structure and electronic properties of such junctions…
In this paper, a systematic study of the influence of various experimental parameters on the morphology and size of CaCO3 crystals after room-temperature crystallization from water in the presence of poly(ethylene glycol)-block-poly(methacrylic acid) (PEG-b-PMAA) is presented. The pH of the solution, the block copolym…
Fluorescence microscopy of nanoscale silver oxide (Ag2O) reveals strong photoactivated emission for excitation wavelengths shorter than 520 nanometers. Although blinking and characteristic emission patterns demonstrate single-nanoparticle observation, large-scale dynamic color changes were also observed, even from the…
Author: Straumal, B. B. et al.; Genre: Book Chapter; Issued: 2001; Keywords: MPI für Metallforschung; Abt. Mittemeijer; PERCENT SI ALLOY, WETTING TRANSITION, ENERGY, TIN, SEGREGATION, AL, TRANSFORMATION, PENETRATION, IMPURITIES, VICINITY; Title: Influence of grain boundary phase transitions on the properties of Cu-Bi…
One ring, two oxidations: The first doubly ring-oxidized metal phthalocyanine complex has been synthesized by galvanostatic electrocrystallization. Copper phthalocyanine was oxidized in the presence of perrhenate anions to form the new molecular compounds [Cu(pc)(ReO4)] and [Cu(pc)(ReO4)2] (structure shown). Single-cr…
The magnetic structure of nonstoichiometric ${\mathrm{LuFe}}_{4+\ensuremath{\delta}}{\mathrm{Al}}_{8\ensuremath{-}\ensuremath{\delta}}$ and ${\mathrm{YFe}}_{4+\ensuremath{\delta}}{\mathrm{Al}}_{8\ensuremath{-}\ensuremath{\delta}}$ compounds with a small Fe excess $(\ensuremath{\delta}\ensuremath{\sim}0.40)$ was invest…
A monotropic smectic A phase is exhibited by adducts of tris(β-diketonato)lanthanide(III) complexes with a non-mesomorphic salicylaldimine Schiff base as Lewis base. Only four terminal alkyl chains were necessary in the Schiff base to induce mesomorphism in [La(dbm)3] (see formula). Hdbm = 1,3-diphenyl-1,3-propanedion…
We study a dynamic model of relaxor ferroelectrics based on the spherical random-bond--random-field model and the Langevin equations of motion written in the representation of eigenstates of the random interaction matrix. The solution to these equations is obtained in the long-time limit where the system reaches an eq…
Magnetic properties correlated to structural transformations, from metastable hexagonal ${\mathrm{CaCu}}_{5}$-type phases to equilibrium tetragonal 1:12 phases, are studied systematically for nanocrystalline $\mathrm{Sm}({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x}{)}_{11}\mathrm{Ti}$ alloys $(x<~2).$ The Riet…