Materials Literature
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This paper presents the results of investigations of the dielectric and spectral properties of NH2(CH3)2Al(SO4)2 × 6 H2O crystals doped with chromium. In particular, it is shown that the dopant noticeably changes the temperature of ferroelectric phase transition and corresponding thermal dipole relaxation with a criti…
The optical convergent-beam technique is used to measure, in 0.3 ms steps, the response of the director in a 4.6-μm-thick ZLI-2293 filled hybrid aligned nematic cell when a 10 kHz, 7 Vrms ac voltage is applied to the cell. The total time taken for the reorientation process is 2.4 ms, with backflow observed during the…
Nuclear magnetic resonance is used to characterize local atomic motions in the glassy and supercooled liquid states of the bulk metallic glass system ${\mathrm{P}\mathrm{d}}_{43}{\mathrm{N}\mathrm{i}}_{10}{\mathrm{C}\mathrm{u}}_{27}{\mathrm{P}}_{20}$. The temperature dependence of the Knight shift reveals that certain…
Gutes Rad ist billig: Eine neue Familie gemischter CeIV-MnIV-Cluster mit Ce:Mn-Verhältnissen zwischen 3:2 und 1:6 wurde hergestellt. Das Bild zeigt den Kern des CeMn6-Komplexes (Ce grün, Mn blau, O rot). Alle Verbindungen weisen antiferromagnetische Wechselwirkungen zwischen den MnIV-Ionen auf.
Gelöst in einer nematischen flüssigkristallinen Phase können starre scheibenförmige Makrolactame hexagonale Röhren bilden. Computermodelle (siehe Bild, O rot, N blau, C grau, H weiß), Raman- und IR-Mikrospektroskopie bringen eine hierarchische Selbstorganisation des Peptids in der flüssigkristallinen Phase zum Vorsche…
The effect of Y3+, La3+, Ga3+, Ti4+ and Nb5+ ions on the physical properties of stoichiometric Mg0.5Cu0.5Fe2O4 ferrite is investigated. The substitutions partially replace the Fe3+ ions and the chemical formula of the investigated ferrites is Mg0.5Cu0.5Fe2−xMe3x/nO4, where Me = Y, La, Ga, Ti and Nb, x = 0 and 0.2, and…
We present electron-spin-resonance (ESR), x-ray-diffraction, and dilatometry studies in a ${\mathrm{La}}_{7/8}{\mathrm{Sr}}_{1/8}{\mathrm{MnO}}_{3}$ single crystal. ESR experiments were performed in the paramagnetic regime ${(T}_{C}$ $\ensuremath{\approx}180\mathrm{K}),$ from 220 K to 570 K at a microwave frequency of…
The analysis of the white photoluminescence (PL) from Si+ and C+ coimplanted SiO2 is reported as a function of the implanted dose. By both steady and time-resolved measurements, the presence of several components in the emission between 2 and 3.3 eV has been resolved. The decays of the PL transients are characterized…
We report the observation of photoluminescence (PL) enhancement and quenching for 580 nm emission following the variation of time decay patterns, induced by Zn2+ and Mn2+ introduction, respectively, in colloidal ZnS:Mn2+ nanoparticles (NPs). The activation and quenching processes are analyzed considering surface nonra…
Degradation of TiO2-based ceramic capacitors was observed after hydrogen incorporation on the termination electrodes of the capacitors via electrolysis of water. Fourier-transform infrared (FTIR) absorption spectra analysis of polished rutile single crystals clearly showed that hydrogen was incorporated into the TiO2…
Außen Molekül – innen Festkörper? Mit einem Durchmesser von 3.7 nm an seiner breitesten Stelle ist [Ag262S100(StBu)62(dppb)6] (dppb=1,4-Bis(diphenylphosphanyl)butan) der größte durch Strukturanalyse charakterisierte Metallchalkogenidcluster (siehe Bild; P grün, S gelb und rot, Ag blau). Das Ag-S-Netz ähnelt Strukturen…
Cation ordering in covalent oxide glasses and melts profoundly affects the macroscopic properties, such as viscosity, diffusivity, and thermodynamic potentials. It is commonly assumed that in glasses and melts nonframework cations such as ${\mathrm{Na}}^{+},$ ${\mathrm{Ca}}^{2+},$ and ${\mathrm{Ba}}^{2+}$ distribute r…
Single crystals of bismuth titanate (BiT) and lanthanum-substituted BiT [Bi4−xLaxTi3O12 (BLT)] were grown by a self-flux method. BLT (x=0.85) showed a smaller remanent polarization (2Pr) along the a(b) axis of 41 μC/cm2 than 98 μC/cm2 for BiT, which mainly originates in its smaller ionic displacements along the a axis…
Ins Ziel getroffen: Die Aufnahme supramolekularer Nanotransporter in Zellen durch Endocytose ist nicht zellspezifisch, bei porösen Geweben, z. B. Tumorgeweben, wurde aber eine hohe passive Selektivität beobachtet. Die verkapselten, oft toxischen Wirkstoffe sind effizient abgeschirmt und entfalten ihre Aktivität durch…
Recent discovery of substrate-selective growth of carbon nanotubes on SiO2 in exclusion to Si, has opened up the possibility of organizing nanotubes on Si/SiO2 patterns in premeditated configurations for building devices. Here, we report the strong dependence of nanotube growth on the SiO2 layer thickness, and the uti…
Dissolved in nematic liquid crystals, rigid disk-shaped macrolactams may form large hexagonal hollow tubes. Computer modeling (see picture, O red, N blue, C gray, H white), Raman and infrared microspectroscopy reveal a hierarchical and self-similar-structured self-assembly of the cyclic peptide in the liquid-crystal m…
Neutron and x-ray powder diffraction have been used to investigate the crystal structures of a sample of the newly-discovered superconducting sodium cobaltate deuterate compound with composition ${\mathrm{Na}}_{0.31(3)}{\mathrm{CoO}}_{2}\ensuremath{\cdot}1.25(2){\mathrm{D}}_{2}\mathrm{O}$ and its anhydrous parent comp…
The electronic structure and structural stability of BeH2 are studied using first-principles density-functional calculation. The calculated structural parameters for α-BeH2 at the equilibrium volume are in very good agreement with experiments. At higher pressures α-BeH2 successively undergoes four structural transitio…
Doughnut-shaped fluorescent molecules: Highly symmetrical, functionally and structurally interesting octakis-m-cyclynes 1 and octakis-p-cyclynes 2 are shown to be a new class of light-emitting materials (see scheme). A pentacoordinate CuII complex of 1 exhibits remarkably intense fluorescence, contrary to the behavior…
The clinical application of macromolecular gadolinium (Gd) complexes as MRI contrast agents is limited by the slow excretion of Gd(III) complexes and consequent long-term tissue accumulation of toxic Gd ions. To alleviate the problem of slow excretion, biodegradable polydisulfide-based macromolecular Gd(III) complexes…