Materials Literature
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The hypothesized racemate separation of cyclooctapyrroles with chiral figure eight conformations-and of metal complexes derived from these ligands-has been realized. The cyclooctapyrrole 1 (as hexadecaethyl derivative), which according to NMR analysis exhibits restricted mobility, and its binuclear palladium and coppe…
The copolymerization of acrylamide with the tetrafunctionalized polyanion [gamma-SiW(10)O(36)(RSiO)(4)](4-) (R=C(3)H(6)OC(O)C(Me)=CH(2)), which acts as a cross-linker, is performed in an aqueous dispersion of maghemite (gamma-Fe(2)O(3)) nanoparticles. It results in a magnetic hybrid hydrogel with superabsorption prope…
The effect of the outer surface of core/shell nanocrystals on the fluorescence quantum yield was observed for InAs/InP and InAs/CdSe core/shells (see picture). For InAs/CdSe we observed substantial enhancement of the fluorescence quantum yield compared to the InAs core, and up to two times larger than the laser dye IR…
We show that a minimal model for viscous fingering with a nematic liquid crystal in which anisotropy is considered to enter through two different viscosities in two perpendicular directions can be mapped to a two-fold anisotropy in the surface tension. We numerically integrate the dynamics of the resulting problem wit…
When granular material is shaken vertically one observes convection, surface fluidization, spontaneous heap formation and other effects. There is a controversial discussion in literature whether there exists a threshold for the Froude number $Γ=A_0ω_0^2/g$ below which these effects cannot be observed anymore. By means…
Within the framework of the effective potential theory of the structural glass transition, we calculate for the p-spin model a static nonlinear susceptibility related to a four-point density correlation function, and show that it grows and diverges in mean field with exponent $γ=1/2$ as the mode coupling critical temp…
Ultrathin membranes consisting of an alternating sequence of cationic and anionic polyelectrolytes were prepared by means of electrostatic layer-by-layer adsorption and investigated on their permeability for NaCl, Na 2 SO 4, and MgCl 2 in aqueous solution. It is demonstrated that the multi-bipolar structure of the pol…
The precise atomic architecture of the catalytically active center is the central topic of the approach presented herein to the design of solid-state catalysts. A wide range of new catalysts may be designed that effect regioselective, shape-selective, and enantioselective conversions, as well as producing high-perform…
The effect of alkali-soluble resin (ASR) postadded to emulsifier-free monodisperse poly( n -butyl methacrylate) latexes (PBMA) on the surface properties of the latex films formed was investigated using the contact angle method. The contact angles of a probe liquid (containing 50:50 wt % ethylene glycol and water) on t…
The band inversion in the PbSnTe compound has been observed by optical and electrical measurements. The samples, high quality Pb1−xSnxTe epitaxial layers, have been grown by molecular-beam epitaxy on (111)BaF2 substrates. Optical transmission measurements have revealed a change in signal of the energy gap temperature…
A stable GaS passivating layer was deposited on GaAs using α-Ga2S3 powder as a single-source precursor. Both good crystal quality and clean GaS/GaAs interface were achieved. Electron-energy-loss spectra showed that the sulfide material has a band gap of 3.0 eV. The valence band discontinuity of the heterostructure was…
The thermogravity/Fourier transform infrared (TG/FTIR) system was used to analyze the mechanism and kinetics of the thermal cracking of poly(ether ether ketone) (PEEK) under different environments. The thermal cracking of PEEK in a helium atmosphere showed that there were two stable cracking reaction regions. In the f…
The structure of the title compound is made up of vanadium oxide layers, with NH + 4 cations intercalated between the layers. Each pair of VO 5 square pyramids is bridged by an edge to form a double V 2 O 8 group. The V 2 O 8 groups are connected by sharing corners to produce a twisted zigzag chain. Each VO 6 octahedr…
The effects of fabrication process and solvent on the structure of polyaniline (PANI) emeraldine base films and their intrinsic properties are examined. Freestanding films of PANI base fabricated from N,N′-dimethyl propylene urea (DMPU) and N-methyl-2-pyrrolidone (NMP) solutions, by casting and spin-coating procedures…
Poly[3,4-bis(3-methylbutylthio)thienylenevinylene], poly[3,4-bis-(S)-(2-methylbutylthio)thienylenevinylene], poly[3′,4′-bis(3-methylbutylthio)-2,2′:5′,2″-terthienylene-5,5″-vinylene], and poly{3′,4′-bis-(S)-[2-methylbutylthio]-2,2′:5′,2″-terthienylene-5,5″-vinylene} have been synthesized. The synthesis starts from the…
The title compound, normal spinel nickel chromite, NiCr 2 O 4 , undergoes a cubic to tetragonal phase transition at low temperature. The crystal structure of the tetragonal phase at 200K was determined by single-crystal X-ray diffraction data. Details of the crystal information, including anisotropic displacement para…
Camphor sulfonic acid (CSA)–doped poly(o-anisidine) (PoAN) has been found to possess the electrical conductivity of 10 S/cm. This value is rather low compared to that of (≈200 S/cm) CSA-doped polyaniline, which may arise from a limited transformation of coil-like conformation to an expanded one. Viscosity data and opt…
The application of microwave energy to the processing of carbon fiber reinforced phenylethynyl-terminated polyimide composites (PETI-5/IM7) was investigated and evaluated with a variable-frequency microwave furnace. The thermal and physical properties of the composites were measured by dynamic mechanical thermal analy…
Vibrationally resolved negative ion photoelectron spectra of B3N− at 355 and 266 nm are presented. Two intense bands are observed with adiabatic detachment energies (ADEs) of 2.923±0.008 eV and 3.063±0.008 eV and markedly different photoelectron angular distributions. Aided by electronic structure calculations, the tw…
A theoretical mixed classical/quantal model for describing the optical properties of free and matrix-embedded metal clusters, based on the time-dependent local-density approximation, is presented. As compared to the previous models involving an inner or/and an outer dielectric medium, all the dielectric effects---scre…