Materials Literature
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Colloidal quantum dots are semiconductor nanocrystals well dispersed in a solvent. The optical properties of quantum dots, in particular the wavelength of their fluorescence, depend strongly on their size. Because of their reduced tendency to photobleach, colloidal quantum dots are interesting fluorescence probes for…
The ground-state structural and electronic properties of ferroelectric $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$ are calculated using density functional theory within the local spin-density approximation (LSDA) and the $\mathrm{LSDA}+U$ method. The crystal structure is computed to be rhombohedral with space group $R3c$…
Hydrogen loading in $\mathrm{X}∕\mathrm{V}(\mathrm{X}=\mathrm{Cr},\mathrm{Mo},\mathrm{Fe})$ supercells as a function of the $\mathrm{H}$ position within the supercell was studied. Preferred $\mathrm{H}$ position is governed by the energy cost of the accompanying volume expansion, which is proportional to the correspon…
Abstract Summary: The phase behavior and optical properties of a cholesteric ternary copolymer, containing nematogenic phenylbenzoate, cholesteric, and photochromic diarylethene side groups, and its mixture with 2 wt.‐% fluorescent dopant were studied. The investigation of the kinetics of a photochemical opening‐cycle…
Abstract We successfully prepared a series of transparent materials with semi‐interpenetrating polymer networks (semi‐IPNs) from castor‐oil‐based polyurethane (PU) and benzyl starch (BS). The miscibility, morphology, and properties of the semi‐IPN films were investigated with attenuated total reflection/Fourier transf…
[Ru(II)(por)(PH(n)Ph(3-n))2], [Os(II)(por)(CO)(PH(n)Ph(3-n))] (n=1, 2), and [Os(II)(F20-tpp){P(OH)Ph2}(PHPh2)] (F20-tpp=5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato dianion) were prepared from the reaction of [M(II)(por)(CO)] (M=Ru, Os) or [Os(VI)(por)O2] with the respective primary/secondary phosphane and chara…
Ein Muster aus magnetischen Mn12-Clustern entsteht, wenn eine Dispersion solcher Cluster in einer Polymermatrix auf eine strukturierte Vorlage (z. B. eine DVD) gegossen wird. Die Erhöhungen auf der Polymeroberfläche verschwinden bei der Einwirkung von Lösungsmitteldampf, und die Cluster konzentrieren sich an deren urs…
We perform a first-principles calculation within the local density approximation $(\mathrm{LDA})+\mathrm{U}$ approximation for the delafossite $\mathrm{Y}\mathrm{Cu}{\mathrm{O}}_{2.5}$, which up to now was considered as a sawtooth lattice. The magnetic interactions are mapped onto a Heisenberg model whose exchange int…
Abstract Summary: Optically active poly[( R )‐ or ( S )‐1,4‐bis(2‐(3′,4′‐ethylenedioxy)thienyl)‐2‐benzoic acid 1‐methylheptyl ester] was prepared by an electrochemical technique and characterized by circular dichroism measurements. It was found that the optical activity and optical rotation of the film could be contro…
Well-aligned core–shell Ga2O3/TiO2 nanowires of high quality are synthesized using a two-stage metal-organic chemical vapor deposition technique. Annealing of the nanowires at high temperatures results in either the formation of Ga2O3–TiO2 ‘nanobarcodes’ (in which the wires have alternating segments of Ga2O3 and TiO2)…
The synthesis and characterization of a family of alternative precursors for the production of CdE nanoparticles (E = S, Se, and Te) is reported. The reaction of Cd(NR2)2 where NR2 = N(SiMe3)2 with n HOR led to the isolation of the following: n = 1 [Cd(mu-OCH2CMe3)(NR2)(py)]2 (1, py = pyridine), Cd[(mu-OC6H3(Me)(2)-2,…
The nonequilibrium relaxational properties of a three-dimensional Coulomb glass model are investigated by kinetic Monte Carlo simulations. Our results suggest a transition from stationary to nonstationary dynamics at the equilibrium glass transition temperature of the system. Below the transition the dynamic correlati…
A combined photoconductivity and luminescence quenching study, both temperature and spectrally resolved, has revealed the role played by electron delocalization in luminescence quenching of ${\mathrm{Ce}}^{3+}$ impurities in the wide band-gap inorganic insulator ${\mathrm{GdAlO}}_{3}$. The anticorrelation found betwee…
An octupolar crystal is produced from octupolar molecules of 1,3,5-tricyano-2,4,6-tris(p-diethylaminostyryl)benzene and its structure is elucidated experimentally using the combined polarization analysis of two-photon fluorescence and second-harmonic generation (SHG). The optimal crystalline packing of the molecules i…
Superparamagnetic particles offer a new way to probe the kinetics of adhesive processes. Two different scenarios of physical adhesion are studied. The thermal activation of van der Waals adhesion is well described by an Arrhenius model. In contrast, it is necessary to go beyond the Arrhenius description to understand…
The stability of the gyroid phase of diblock copolymers has been studied using combined oscillatory shear and small-angle neutron scattering (SANS) techniques. It is shown that the gyroid phase of polystyrene−polyisoprene (PS−PI) is unstable when exposed to combined large-amplitude and high-frequency shear deformation…
The gene phaPAh, encoding the protein phasin that is associated with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) granule of Aeromonas hydrophila 4AK4, was cloned and characterized. Recombinant strains harboring additional copies of the phasin gene (phaPAh) and the polyhydroxyalkanoate (PHA) synthase gene (p…
A recent high pressure experiment on ${\mathrm{L}\mathrm{a}\mathrm{A}\mathrm{l}\mathrm{O}}_{3}$ has revealed that the compound is an exception for the ``general rule'' of displacive phase transition associated with zone-boundary phonons. In the present study, the experimental result is successfully confirmed by first…
Focused ion beam (FIB) lithography can be used to selectively close nanochannels in an ordered array on an anodic-alumina film, producing templates with the nanochannels arranged in custom-designed geometries (see Figure). Nanochannel closing can be monitored by in-situ FIB imaging. Nanodevices such as photonic-crysta…
The synthesis of a zinc porphyrin linked conjugated homopolymer is presented. The synthetic strategy employed a directional polymerization of 1-iodo-2,5-dioctyl-4‘-ethynyltolane in the presence of [10,20-bis(3,5-bis- tert -butylphenyl]-5,15-diethynylporphinato]zinc(II) ( 12 ) or [10,20-bis(3,5-bis- tert -butylphenyl]-…