Materials Literature
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Ligand formed by CN bond cleavage: Transition-metal-promoted heterolytic cleavage of the CN bond in 1 results in the formation of five new complexes of cis hyponitrite with Group 10 transition metals. The new complexes include [Ni(η2-O2N2)(dppf)] (dppf=1,1′-bis(diphenylphosphanyl)ferrocene) which is structurally cha…
A set of twelve porphyrin dimers has been prepared to give information on how the type of connectivity between a porphyrin core and a bridge can influence the interporphyrin electronic interaction. The new porphyrin systems are substituted directly at the meso position with an oligothiophene chain tethered either with…
We examine the Mn concentration dependence of the electronic and magnetic properties of optimally annealed ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ epilayers for $1.35%<~x<~8.3%.$ The Curie temperature ${(T}_{c}),$ conductivity, and exchange energy increase with Mn concentration up to $x\en…
Abstract The modification of high‐impact polystyrene (HIPS) was accomplished by melt‐grafting glycidyl methacrylate (GMA) on its molecular chains. Fourier transform infrared spectroscopy and electron spectroscopy for chemical analysis were used to characterize the formation of HIPS‐g‐GMA copolymers. The content of GMA…
Abstract Jute fibers were treated with 5% NaOH solution for 4 and 8 h, respectively, to study the mechanical and impact fatigue properties of jute‐reinforced vinylester resin matrix composites. Mechanical properties were enhanced in case of fiber composites treated for 4 h, where improved interfacial bonding (as evide…
Nicht chiral und doch ferroelektrisch: Bei konventionellen fluiden Systemen heben sich die Dipolmomente der einzelnen Moleküle gegenseitig auf, und eine makroskopisch apolare Struktur entsteht. Hier wird gezeigt, wie sich durch gezieltes Moleküldesign und Nutzung von Mikrosegregationseffekten die Selbstorganisation vo…
Der chirale Organokatalysator Bisflavin 1 katalysiert asymmetrische Baeyer-Villiger-Reaktionen von Cyclobutanonen mit H2O2 (siehe Schema). Die entsprechenden Lactone werden mit bis zu 74 % ee erhalten.
Photoluminescence (PL) from composites of 7- and 15-nm silica (amorphous ${\mathrm{SiO}}_{2})$ nanoparticles and bulk type-III fused silica induced by two-photon band-to-band excitation with 193-nm (6.4-eV) ArF laser light has been measured in time-resolved detection mode. The PL spectra taken for 15-nm particles allo…
Stopcock fluorophores at the ends of zeolite L channels can trap electronic excitation energy from pyronine+ molecules inside the crystal (see scheme, top). The reverse process, that is, the injection of electronic excitation energy through such stopcocks (bottom), was achieved with oxonine+ molecules inside the zeoli…
Efficient guest exchange: The organic zeolite analogue TPP⋅x(THF) (x=0.35–0.65) takes up I2 quickly when exposed to iodine vapor. The previously colorless crystals (a) color at the ends (b), and after 1–2 days the iodine has permeated all the way through the crystal (c). The conductivity values of the TPP⋅y(I2) crysta…
A systematic morphosynthesis of barium chromate particles has been performed by using double-hydrophilic block copolymers (DHBCs), which consist of a hydrophilic solvating block and a hydrophilic binding block, as crystal growth modifiers to direct the controlled precipitation of barium chromate from aqueous solution.…
Molecular dynamics (MD) simulations with a modified Tersoff potential have been used to investigate cascade overlap, damage accumulation, and amorphization processes in 3C-SiC over dose levels comparable to experimental conditions. A large number of 10 keV displacement cascades were randomly generated in a model cryst…
We observe twofold shell filling in the spectra of closed one-dimensional quantum dots formed in single-wall carbon nanotubes. Its signatures include a bimodal distribution of addition energies, correlations in the excitation spectra for different electron number, and alternation of the spins of the added electrons. T…
Dendrimers composed entirely of building blocks known to be biocompatible or degradable in vivo to natural metabolites were synthesized using a high yield divergent approach. This synthesis is amenable to the design and development of new biomaterials that are of interest for a variety of medical applications, includi…
Six Mo dimers arranged around a central PO4 tetrahedron form the core of the novel ε-Keggin polyoxocation [ε-PMo12O36(OH)4{La(H2O)4}4]5+ (see structure) capped with four {La(H2O)4}3+ units. A 31P NMR spectroscopy study shows that the ε-Keggin ion is unstable in aqueous solution, and leads to the formation of a polyani…
Magnetoresistive properties of granular Bi-based HTSC with trapped magnetic fields are investigated in the temperature region near superconducting transition . The effect of trapped field and transport current values and orientations on the field dependence of magnetoresistance is studied. It is found that for the mag…
A measurement of the hole density in the ferromagnetic semiconductor ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ is notoriously difficult using standard transport techniques due to the dominance of the anomalous Hall effect. Here we report a spectroscopic measurement of the hole density in four ${\m…
The main and side reactions of the three selective catalytic reduction (SCR) reactions with ammonia over TiO 2 −WO 3 −V 2 O 5 catalysts have been investigated using synthetic gas mixtures matching the composition of diesel exhaust. The three SCR reactions are standard SCR with pure NO, fast SCR with an equimolar mixtu…
Abstract Jute fibers were treated with 5% NaOH solution for 2, 4, 6, and 8 h to study the performance of the fibers as a reinforcing material in the composites. Thermal analysis of the fibers was done by the DTG and DSC technique. The moisture desorption was observed at a lower temperature in the case of all the treat…
In conventional fluids the molecular dipole moments of the individual molecules cancel out, which leads to a macroscopic apolar structure. Directed molecular design using microsegregation and tailoring the molecular shape of compounds such as 1, can lead to fluid layer structures with a macroscopic polar order.