Highly oriented star-like patterns observed on GaSe epilayers grown on Si(111)

Epitaxial lamellar gallium selenide (GaSe) semiconductors have been grown on trench-patterned silicon (Si) substrates by molecular beam epitaxy. An intriguing star-like patterned morphology was identified by atomic force microscopy on these epilayers. This non-trivial feature can be correlated with the accumulation of stacking faults of two concurrent epitaxial domains around self-oriented triangular pits developed earlier on the Si(111) surface by the chemical etching. Crystallographic considerations show how the stars can be formed.     

Functional topography of cat primary auditory cortex: response latencies

Minimum onset latency (Lmin) of single- and multiple-unit responses were mapped in the primary auditory cortex (AI) of barbiturate-anesthetized cats. Contralateral Lmin for multiple units was non-homogeneously distributed along the dorso-ventral/isofrequency axis of the AI. Responses with shorter latencies were more often located in the central, more sharply tuned region while longer latencies were more frequently encountered in the dorsal and ventral portions of the AI. For single units, a large scatter of Lmin values was found throughout the extent of the AI including cortical depth. The relationship between Lmin and previously reported spectral, intensity and temporal parameters was analyzed and revealed statistically significant correlations between minimum onset latency and the following response properties in some but not all studied animals: sharpness of tuning of a frequency response area 10 dB above threshold, broadband transient response, strongest response level, monotonicity of rate/level functions, dynamic range, and preferred frequency modulation sweep direction. This analysis suggests that Lmin is determined by several independent factors and that the prediction of Lmin based on relationships with other spectral and temporal response properties is inherently weak. The spatial distribution and the functional relationship between these response parameters may provide an important aspect of the time-based cortical representation of specific features in the animal's natural environment.     

Electro-winning of chromium from chromic oxide by chlorination in fused salt and subsequent electrolysis

The electro-winning of chromium from chromic oxide after chlorination in a carbon-containing fused sodium chloride flux is described. Only low values of current efficiency (based on the reaction Cr³⁺ + 3e ← Cr) can be attained. The effects of concentration of chromic and chromous chlorides in the melt, of current density and of melt temperature are reported. The conclusion is reached that the major factor responsible for the low current efficiency is the re-solution of deposited metal by anodic chlorine.     

Plasma and ion-beam-assisted deposition of multilayers for tribological and corrosion protection

Multilayers of Ti/TiN and Al/AlN were deposited on steel and silicon by magnetron sputtering and ion-beam-assisted deposition. Compositions and film thicknesses were determined by Rutherford backscattering. Hardness was measured with a dynamic ultramicrohardness tester. The corrosion protection potential in an aqueous environment was evaluated by electrochemical techniques. The results are discussed in terms of the structure and composition of the multilayer arrangement. It turns out that the multilayer coatings generally show a better corrosion protection performance than both the pure metal and the pure nitride films, with an optimum ratio of nitride film thickness to metal film thickness for a maximum corrosion protection effect. The hardness values are in between that of nitride single film and those of metal single films. Deposition of multilayers with the possibility of selecting the thickness ratio of metal to nitride film for particular mechanical and chemical requirements allows a controlled adaption of the film features to a given application problem.     

From IMS Management to SOA Based NGN Management

Although IP Multimedia Subsystem (IMS) based Next Generation Networks (NGNs) are already emerging as the common session control platform for converging fixed, mobile and cable networks, harmonized solutions for the management of these converged platforms have still got to be developed. This document describes a hands-on approach to NGN Management. Started with IMS specific management systems, succeeding research had to take into account the importance of the management of NGN SDPs as well. This work shows that the hybrid nature of an NGN, where services can be delivered at the IMS layer, by SIP signaling mechanisms, as well as at the SDP, via Web Services, requires a harmonized management approach. Taking into account Service Oriented Architecture (SOA) principles and policy based model driven architectures, this work shows that a unification of service composition and service management already at the workflow creation level, bares significant benefits in terms of automation and harmonization. Following the SOA paradigm, the approach presented here does not differentiate between business process management (BPM) and management process management. Focusing on Telemanagement Forum’s enhanced Telecom Operations Map service fulfillment and service assurance operations, this document describes an New Generation Software and Services (NGOSS) based implementation of a unified Operation Support System (OSS) for NGNs that encompasses many problems of former stovepipe management solutions in terms of automation, flexibility and manageability.     

The effect of temperature and radiation on flavonol aglycones and flavonol glycosides of kale (Brassica oleracea var. sabellica)

The winter crop kale has a complex profile of different glycosylated and acylated flavonol glycosides which may be affected by global warming. To the best of our knowledge, compound–climate relationships for flavonol aglycones and flavonol glycosides were established for the first time. The investigated 10 major flavonol glycosides responded structure-dependent in the investigated temperature range between 0 and 12 °C and the photosynthetic active radiation range between 4 and 20 mol m⁻² d⁻¹, e.g. the decrease in temperature led to an increase in sinapic acid monoacylated and diacylated quercetin glycosides, while the sinapic acid monoacylated kaempferol glycosides showed a maximum at 4.5 °C. Furthermore, the hydroxycinnamic acid residues and the different number of glucose moieties in the 7-O position affected the response of kaempferol triglucosides. Consequently, global warming would result in lower concentrations of antioxidant-relevant quercetin glycosides in winter crops, suggesting a production at e.g. higher altitudes due to lower temperature.     

Self-healing through microencapsulated agents for protective coatings

The use of microcapsules containing healing agents, which can serve as source of self-healing for coatings, was investigated. The appropriate self-repairing coatings are designed to be used for heavy-duty corrosion protection or for the protection of moisture-sensitive substrates like wood. Microcapsules based on thermoset resins (urea–formaldehyde and melamine–formaldehyde) which contained components of different chemical natures (resins or inhibitors) were fabricated using emulsion techniques. The subsequent characterization included optical, fluorescence, and electron microscopy as well as adapted microindentation techniques to determine capsule break forces. Different model coatings were formulated making use of varying amounts of healing agent-charged microcapsules. The coated samples were then injured under controlled conditions (by Erichsen cupping in the case of steel, by simulated hail in the case of wood) and then subjected to salt spray testing (natural and accelerated), weathering, or even real-life exposure, always in comparison with a blank. The results obtained demonstrate the superiority of microcapsule-based self-healing coatings compared to classical protection formulations, and appropriate coating systems have in the meantime been successfully brought to the market.     

Partially fluorinated polymer networks: Surface and tribological properties

Functionalization of epoxy-based networks by the preferential surface enrichment of perfluorinated tails to achieve hydrophobic surface is described. Two series of crosslinked fluorinated epoxy-based materials containing variable fluorine contents (from 0 to 5 wt % F) were prepared using formulations based on partially fluorinated diamine, epoxy monomer and a curing agent. The epoxy monomer was based on diglycidyl ether of bisphenol A (DGEBA) while the curing agents were either propyleneoxide diamine (JEFFAMINE) or 4,4′-methylenebis(3-chloro 2,6-diethylaniline) (MCDEA). The selected fluorinated epoxies (FE) were: 2,2,3,3,4,4,5,5,6,6,7,7,8,9,9,9-hexadecafluoro-8-trifluoromethyl nonyloxirane (FED3) and 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-heptadecafluoro nonyloxirane (FES3). The influence on surface properties of the architecture of FE, and the molecular structure of the unit building blocks was analyzed and discussed. It was found that both series showed high hydrophobicity and oleophobicity, independently of the crosslink density, bulk composition, and curing conditions. XPS measurements showed a surface composition much richer in fluorinated segments than expected from bulk composition. Fluorine enrichment was also manifested at the polymer/aluminium interface for JEFFAMINE-based networks. This observation is discussed in terms of the molecular weight dependence of surface tension and configurational entropy of the thermosetting matrix. At least for the range of this study, while increasing the amount of fluorine incorporated in both network series, dynamic friction is reduced due to surface migration of fluorine species during polymerization     

Electrochemical characterization of electrolytes for lithium-ion batteries based on lithium difluoromono(oxalato)borate

The salt lithium difluoromono(oxalato)borate (LiDFOB) showed some promising results for lithium-ion-cells. It was synthesized via a new synthetic route that avoids chloride impurities. Here we report the properties of its solutions (solvent blend ethylene carbonate/diethyl carbonate (3:7, mass ratio), including its conductivity, cationic transference number, hydrolysis, Al-current collector corrosion-protection ability and its cycling performance with some electrode materials. Some Al-corrosion studies were also performed with the help of our recently developed computer controlled impedance scanning electrochemical quartz crystal microbalance (EQCM) that proofed to be a useful tool for battery material investigations.