Materials Literature
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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…
An incomplete transformation cycle induces a kinetic stop in the following complete transformation cycle in shape memory alloys. Therefore, the kinetic stop can be regarded as a memory of the previous arrest temperature. Herein, we show that the temperature memory effect of a nickel–titanium shape memory alloy can be…
Epitaxial thin films of BiMnO3 were deposited on single-crystal substrates of (100)-oriented SrTiO3 by pulsed-laser deposition. Structural analysis by x-ray diffraction, electron diffraction, and transmission electron microscopy (TEM) indicated that the films were monoclinic and twinned with two dominant orientation r…
Wheels within wheels: A new family of mixed cerium(IV)–manganese(IV) clusters has been prepared spanning a range of Ce:Mn ratios from 3:2 to 1:6. The unusual core of the latter CeMn6 complex is shown (Ce green, Mn blue, O red). All the compounds exhibit antiferromagnetic interactions between their constituent MnIV ion…
The electrical properties of Schottky contacts (SCs) produced ex situ on n-type ZnO single crystals and epitaxial thin films were investigated. Electron beam induced current imaging was used to study lateral variations of the current induced in the space charge region of the SC. Further, the effective barrier height w…
We study a model in which particles interact through a hard-core repulsion complemented by a short-ranged attractive potential of the kind found in colloidal suspensions. Combining theoretical and numerical work we locate the line of higher-order glass-transition singularities and its end point-named A4-on the fluid-g…
With a maximum diameter of 3.7 nm, [Ag262S100(StBu)62(dppb)6] (dppb=1,4-bis(diphenylphosphanyl)butane) is the largest structurally characterized metal chalcogenide cluster (see picture, P green, S yellow and red, Ag blue). The AgS substructure has a relationship to structural characteristics observed in binary Ag2S p…
Von tropfnass bis knochentrocken: Das Konzept der reversiblen Umschaltung zwischen Superhydrophilie und Superhydrophobie einer Oberfläche (siehe Bild) beruht auf der rauigkeitsabhängigen thermoresponsiven Benetzbarkeit von Poly(N-isopropylacrylamid).
Massive ZnO nanowires with the mean diameter of 20 nm have been rapid synthesized by evaporation of metal zinc at 900 °C in the quartz tube. Metal catalyst, graphite additive, and vacuum are not necessary, and, more importantly, it is very convenient and effective for large-scale industrialization. The hydrogen storag…
Recent experimental results on the static or quasistatic response of granular materials have been interpreted to suggest the inapplicability of the traditional engineering approaches, which are based on elasto-plastic models (which are elliptic in nature). Propagating (hyperbolic) or diffusive (parabolic) models have…
A detailed study of the zero-field electrical resistivity and magnetoresistance for the metallic members of the LaNi_{1-x}Co{x}O3 solid solution with 0.3<=x<=0.6 is reported. The low temperature resistivity of the compounds with 0.3<=x<=0.5 exhibits a logarithmic dependence that is characteristic of systems with spin…
Dense distributions of string-like objects in material media are considered in terms of continuum field theory. The strings are assumed to carry a quantized abelian topological charge, such as the Burgers vector of dislocations in solids or magnetic flux of supercurrent vortices in type-II supercondoctors. Within this…
This letter studies the promising application of carbon nanotubes as nanoresonators. Both single- and double-walled carbon nanotubes are considered and the significant difference in the vibration behavior between them has been identified. The individual tube wall is treated as frame-like structures and simulated by th…