Materials Literature
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Dielectric relaxation of ethanol and 1-propanol have been measured in a wide fluid phase including the supercritical condition for the first time. The results of the static permittivity ε(0) and the dielectric relaxation time τD are presented in the temperature and pressure range up to 670 K and 30 MPa. Kirkwood’s g-f…
Abstract Resorbable poly(ester anhydride) networks based on ε‐caprolactone, L ‐lactide, and D,L ‐lactide oligomers were synthesized. The ring‐opening polymerization of the monomers yielded hydroxyl telechelic oligomers, which were end‐functionalized with succinic anhydride and reacted with methacrylic anhydride to yie…
Using tapping mode atomic force microscopy, we studied the influence of molar mass (13.9−183 kg/mol) on the lamellar orientation at the surface of thin films of symmetric polystyrene−polybutadiene diblock copolymers prepared via spin-coating and by slow solvent-casting. The ratio between film thickness and lamellar th…
Efficient outcoupling of surface-plasma waves to radiation modes by use of dielectric diffraction gratings on a flat metallic surface is discussed. The dielectric gratings, which have a surface-relief structure with only several tens of nanometers in peak-to-trough height on a flat metal surface, can efficiently extra…
Ein dreifach verbrücktes Porphyrindimer, das mit zwei [60]Fulleren-Einheiten konjugiert ist, kann bis zu fünfzehn Elektronen reversibel aufnehmen. In seinen photophysikalischen Eigenschaften unterscheidet es sich grundlegend von den bislang bekannten Porphyrin-Fulleren-Konjugaten: Photochemische Anregung der C60-Einhe…
Electronic states are calculated in boron carbonitride (BCN) alloy nanotubes with a simple tight-binding model. Random replacement of carbon atoms with boron and nitrogen (B–N) ones in metallic carbon nanotubes mainly causes level broadening and the nanotubes remain metallic. On the other hand, the energy gap of boron…
The influence of stirrer material and agitation rate on the nucleation of batch crystallized l -glutamic acid from supersaturated aqueous solutions using temperature programmed cooling is investigated. Results obtained at the 450 mL scale size using a retreat curve impeller together with a single baffle reveal that st…
We discuss the 'memory effect' discovered in the 1960s by Kovacs in temperature shift experiments on glassy polymers, where the volume (or energy) displays a non-monotonic time behaviour. This effect is generic and is observed in a variety of different glassy systems (including granular materials). The aim of this pap…
A suggested application of a thermoelectric generator is to exploit the natural temperature difference between the air and the soil to generate small amounts of electrical energy. Since the conversion efficiency of even the best thermoelectric generators available is very low, the performance of the heat sinks providi…
The influence of the dipole interaction on the magnetic anisotropy of Gd compounds is investigated. Available data on ferromagnets and antiferromagnets with different crystal structures are discussed and complemented by new neutron scattering experiments on ${\mathrm{GdCu}}_{2}\mathrm{In},$ ${\mathrm{GdAu}}_{2}{\mathr…
A novel catalytic role for transition-metal cations in the homogeneous conversion of the nitrogen oxides NO2, NO, or N2O and CO into N2 and CO2 is demonstrated by thermodynamic and kinetic studies of gas-phase reactions of 29 transition-metal cations and some of their oxides (see scheme). Fe+, Os+, and Ir+ ions are sh…
ZnO films were electrodeposited on porous silicon templates with different porosities. The photoluminescence (PL) spectra of the samples before and after deposition of ZnO were measured to study the effect of template porosity on the luminescence properties of ZnO/porous Si composites. As-prepared porous Si (PS) templ…
Auf den Punkt gebracht: Der Zeolithkatalysator TS-1B für die Oxidation von Benzol mit Wasserstoffperoxid wird durch Modifizierung von Titan-Silicalit mit NH4HF2 und H2O2 erhalten. In Gegenwart von Sulfolan bleibt die Oxidation mit diesem neuen Katalysator selektiv auf der Stufe von Phenol stehen (siehe Schema).
The development of a high efficiency thermoelectric (TE) stack, which is a united system of thermoelectric modules and a heat exchanger, has been made to advance the applications of electrical power generation to vehicles. The thermoelectric materials under investigation are mostly heavily doped CoSb/sub 3/ and filled…
Pressure and photoirradiation effects on the structural properties were investigated for a transition metal cyanide, $\mathrm{RbMn}[\mathrm{Fe}(\mathrm{CN}{)}_{6}],$ with perovskitelike structure by means of high-angle resolved synchrotron-radiation x-ray powder diffraction. We have found that (1) photoirradiation by…
Magnetic properties after irradiation of a 1:4 mixture of Co(SCN)2 and 4-(alpha-diazobenzyl)pyridine in frozen solution were investigated by ac and dc magneto/susceptometry. Observations of the frequency dependence of chi'' signals and of a hysteresis loop at 2 K in ac and dc measurements, respectively, indicate that…
A series of sulfated zirconia samples were synthesized by a two-step sol−gel technique using zirconium propoxide as a precursor having two different concentrations, hydrolyzed with aqueous ammonia at pH 9−10 and sulfated with sulfuric acid. Effects of various synthetic parameters were studied on the structural, textur…
A novel hydrogel system based on oligo(poly(ethylene glycol) fumarate) (OPF) is currently being investigated as an injectable carrier for marrow stromal cells (MSCs) for orthopedic tissue engineering applications. This hydrogel is cross-linked using the redox radical initiators ammonium persulfate (APS) and ascorbic a…
Through the incorporation of a phenanthroline ligand into the oxazine moiety of photochromic spirooxazines, a series of photochromic spirooxazine-phenanthroline metal complexes have been synthesized, resulting in tunable and significantly increased photoresponsivities. Such systems are of interest for the investigatio…
Up to fifteen electrons are reversibly accommodated in a triply fused porphyrin dimer conjugated to two [60]fullerene moieties. Its photophysical properties differ completely from those of the many known porphyrin–fullerene dyads: Photoexcitation of the C60 moieties results in quantitative sensitization of the low-lyi…