Materials Literature
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Die exakte atomare Architektur des katalytisch aktiven Zentrums steht im Zentrum des hier vorgestellten Ansatzes zum Design von Feststoffkatalysatoren. Er lieferte eine große Bandbreite neuartiger Katalysatoren unter anderem für regioselektive, formselektive und enantioselektive Reaktionen, für die effiziente Isomeris…
Poly(bisphenol A carbonate) was synthesized by solid-state polymerization (SSP) using supercritical CO 2 to induce crystallinity in low molecular weight polycarbonate beads. The CO 2 -induced crystallization was studied as a function of time, temperature, molecular weight, and pressure. There was an optimum temperatur…
Rigid terpyridine-based building blocks allow easy access to large polymetallomacrocycles (see picture) through a self-assembly process. Such routes are envisioned to provide one-step methods to higher order motifs and facilitate the creation of precisely organized, metal-based networks for new energy storage devices.
Extremely small 1.4-nm size mercaptoethanol-stabilized ZnS clusters have been synthesized with narrow size distribution. The structure of these clusters was studied by wide-angle X-ray scattering. The scattering curves were compared with the calculated scattered intensity of a variety of model clusters (ZnS) N and dif…
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…