Materials Literature
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A Sb-mediated growth technique is developed to deposit Ge quantum dots (QDs) of small size, high density, and free of dislocations. These QDs were grown at low growth temperature by molecular beam epitaxy. The photoluminescence and absorption properties of these Ge QDs suggest an indirect-to-direct conversion, which i…
A method for transforming low-density configurations of rods, discs or spheres to rigidly jammed packings is described. In D dimensions, it repeats a cycle in which each particle is moved towards to the centre of the cage of the D + 1 neighbouring particles that most closely contain it. Low-density fluid configuration…
Designed as a ferromagnetically coupled spin pentamer, the macrocyclic polyradical 1 possesses an average spin of S=10 in the ground state. This is the highest spin quantum number that has yet been measured for an organic molecule. Ar=tBuC6H4.
Infrared (IR) transmittance spectra were measured for a series of samples with different particle sizes. Two extra absorption peaks appear when the average particle size of the samples is smaller than 60 nm; these peaks can be ascribed to the surface stretching and bending modes of the octahedra. When the average part…
Tempern von Polystyrolfilmen, die die neuartigen flüssigkristallinen Coronendiimide 2 enthalten, führt in wenigen Sekunden zu einer Verschiebung der Emission, was zur pixelweisen Einfärbung und mithin für optische Anzeigen genutzt werden könnte. Die Photolumineszenzeigenschaften von 2 in fester Matrix hängen von der A…
This paper discusses the isothermal pressure behaviour of the relaxation times for supercooled glass-forming liquids. Analysis based on reference data and the authors' measurements of dielectric relaxation is carried out for both strong and fragile glass formers. All of the experimental relaxation times clearly exhibi…
The energy distribution of the secondary electrons for chemical vacuum deposited diamond films with negative electron affinity (NEA) was investigated. It was found that while for completely hydrogenated diamond surfaces the negative electron affinity peak in the energy spectrum of the secondary electrons is present fo…
We address the role of the local disorder created by substitutional ions in L2/3A1/3MnO3 oxides, on the pressure dependence of the Curie temperature dln TC/dP. A number of manganites having distinct averaged lanthanide R0 radii and size variance σ2 have been prepared and their resistivity measured up to 11 kbar. It is…
Symmetric superlattice structures consisting of alternating atomic-scale layers of KTaO3 and KNbO3 with variable periodicity were grown on KTaO3 substrates by pulsed laser deposition. The in-plane structure of KNbO3 closely matches that of the KTaO3 substrate, resulting in KTaO3/KNbO3 heterostructures that are uniform…
A sonochemical procedure for the preparation of cadmium sulfide (CdS) nanoparticles coated on submicron spherical silica particles has been described. Ultrasonic irradiation of a slurry of silica microspheres, cadmium sulfate, and thiourea in an aqueous medium for 3 h under ambient air yields cadmium sulfide–silica (C…
Liquid ${\mathrm{Zr}}_{46.8}{\mathrm{Ti}}_{8.2}{\mathrm{Cu}}_{7.5}{\mathrm{Ni}}_{10}{\mathrm{Be}}_{27.5}$ has been studied by quasielastic neutron scattering. The microscopic dynamics of this bulk glass forming alloy deviates qualitatively from simple metallic liquids; it shows two-step structural relaxation like othe…
Intriguing association behavior in solution is exhibited by the rigid macrocycle 1. For instance, it reacts with organic cations to give ternary complexes of the composition (1⋅cation)⋅1, and with analogous macrocycles without cyano groups it forms heteroaggregates. R=CO2C8H17.
Direct formation of surface relief gratings at modest intensities on azobenzene polymers has recently been accomplished. Unusual optical erasure of these surface relief gratings was observed. It is found that the optical erasure is dependent on the polarization state of the erasing beam as well as that of the recordin…
An anion is encapsulated in the center of the new cage compound [Ni6(atu)8X]X3 (X=Cl—for the structure see picture—or Br; Hatu=amidinothiourea). A combination of Lewis acid–base and hydrogen-bonding interactions cause the square-planar [Ni(Hatu)2]2+ units, after deprotonation, to assemble to form this compound. A rema…
The topography of the Landau free energy surface of a diblock copolymer melt is found to exhibit a low-energy pathway connecting the local minima of the cylinder (C) and gyroid (G) mesophases. Energy barriers and stability limits are accurately evaluated for experimentally relevant conditions, and they imply that the…
Manganese(II) complexes of imidazolyl-substituted chelating nitronylnitroxides are characterized by a stereoselective arrangement of the metal centers and the ligands to give a honeycomblike layer structure (shown on the right). The magnetic properties at high temperature indicate the presence of a ferrimagnetic struc…
Si nanocrystals (diameter 2–5 nm) were formed by 35 keV Si+ implantation at a fluence of 6×1016 Si/cm2 into a 100 nm thick thermally grown SiO2 film on Si (100), followed by thermal annealing at 1100 °C for 10 min. The nanocrystals show a broad photoluminescence spectrum, peaking at 880 nm, attributed to the recombina…
A highly enriched spindle pole preparation was prepared from budding yeast and fractionated by SDS gel electrophoresis. Forty-five of the gel bands that appeared enriched in this fraction were analyzed by high-mass accuracy matrix-assisted laser desorption/ ionization (MALDI) peptide mass mapping combined with sequenc…
We have proposed new algorithms for the numerical integration of the equations of motion for classical spin systems. In close analogy to symplectic integrators for Hamiltonian equations of motion used in Molecular Dynamics these algorithms are based on the Suzuki-Trotter decomposition of exponential operators and unli…
The largest inorganic molecular system so far, [(MoO3)176(H2O)80H32] (1; the picture on the right shows the polyhedral representation), which has been characterized by X-ray structure analysis, possesses a cavity of diameter 2.3 nm and remarkably shows the stoichiometry of a (reduced) protonated and hydrated “molecula…