The confinement of phonon propagation in TiAlN/Ag multilayer coatings with anomalously low heat conductivity

TiAlN/Ag multilayer coatings with a different number of bilayers and thicknesses of individual layers were fabricated by DC magnetron co-sputtering. Thermal conductivity was measured in dependence of Ag layer thickness. It was found anomalous low thermal conductivity of silver comparing to TiAlN and Ag bulk standards and TiAlN/TiN multilayers. The physical nature of such thermal barrier properties of the multilayer coatings was explained on the basis of reflection electron energy loss spectroscopy. The analysis shows that nanostructuring of the coating decreases the density of states and velocity of acoustic phonons propagation. At the same time, multiphonon channels of heat propagation degenerate. These results demonstrate that metal-dielectric interfaces in TiAlN/Ag coatings are insurmountable obstacles for acoustic phonons propagation

Reversible Graphene decoupling by NaCl photo-dissociation

We describe the reversible intercalation of Na under graphene on Ir(111) by photo-dissociation of a previously adsorbed NaCl overlayer. After room temperature evaporation, NaCl adsorbs on top of graphene forming a bilayer. With a combination of electron diffraction and photoemission techniques we demonstrate that the NaCl overlayer dissociates upon a short exposure to an X-ray beam. As a result, chlorine desorbs while sodium intercalates under the graphene, inducing an electronic decoupling from the underlying metal. Low energy electron diffraction shows the disappearance of the moir\'e pattern when Na intercalates between graphene and iridium. Analysis of the Na 2p core-level by X-ray photoelectron spectroscopy shows a chemical change from NaCl to metallic buried Na at the graphene/Ir interface. The intercalation-decoupling process leads to a n-doped graphene due to the charge transfer from the Na, as revealed by constant energy angle resolved X-ray photoemission maps. Moreover, the process is reversible by a mild annealing of the samples without damaging the graphene

Interface-Induced Plasmon Nonhomogeneity in Nanostructured Metal-Dielectric Planar Metamaterial

Transformations of the electronic structure in thin silver layers in metal-dielectric (TiAlN/Ag) multilayer nanocomposite were investigated by a set of electron spectroscopy techniques. Localization of the electronic states in the valence band and reduction of electron concentration in the conduction band was observed. This led to decreasing metallic properties of silver in the thin films. A critical layer thickness of 23.5 nm associated with the development of quantum effects was determined by X-ray photoelectron spectroscopy. Scanning Auger electron microscopy of characteristic energy losses provided images of plasmon localization in the Ag layers. The nonuniformity of plasmon intensities distribution near the metal-nitride interfaces was assessed experimentally

3D-QSAR/CoMFA Models as a Tool for Biocatalysis and Protein Engineering

The x-ray structure of an enzyme is taken into account, when available, as the reference model to explain catalytic activity and selectivity. Unfortunately, in most of the cases the structure is available only as apostructure, i.e. without the substrate bound to the active site, and it is strange to find many different enzyme-substrate complexes of a specific enzyme as crystals. Moreover this structure is not the "real" structure of the protein during catalysis as the crystal is stationary. In this paper we propose the use of CoMFA models to evaluate the differences betweenthe crystal and the real structure of the enzyme under reaction conditions. In addition to the stationary nature of a crystal, the experimental limitations of crystallographic techniques to obtain crystals in a fast and reliable manner, give a chance to the creation of CoMFA models by evaluating the easy to obtain catalytic properties of enzyme variants to provide information about the structural changes produced by the mutations. By means of the evaluation of different structures as substrates CoMFA models will not only provide information about the structure of the enzyme, but also about the flexibility and potential conformational changes of the substrate binding site

Patterson Function from Low-Energy Electron Diffraction Measured Intensities and Structural Discrimination

Surface Patterson Functions have been derived by direct inversion of experimental Low-Energy Electron Diffraction I-V spectra measured at multiple incident angles. The direct inversion is computationally simple and can be used to discriminate between different structural models. 1x1 YSi_2 epitaxial layers grown on Si(111) have been used to illustrate the analysis. We introduce a suitable R-factor for the Patterson Function to make the structural discrimination as objective as possible. From six competing models needed to complete the geometrical search, four could easily be discarded, achieving a very significant and useful reduction in the parameter space to be explored by standard dynamical LEED methods. The amount and quality of data needed for this analysis is discussed.Comment: 5 pages, 4 figure

Yellowtail flounder, redfish (Sebastes spp.) and witch flounder indices from the Spanish Survey conducted in Divisions 3NO of the NAFO Regulatory Area

Since 1995, Spain carries out a spring stratified random bottom trawl survey in Div. 3NO of the NAFO Regulatory Area. Total mean catches, biomass and mean numbers for yellowtail flounder (Limanda ferruginea) are presented for the period 1995-8 for redfish (Sebastes spp.) for the period 1997-2018 and for witch flounder (Glyptocephalus cynoglossus) for the period 2002-2018. Detailed indices are presented from 2013. Yellowtail flounder indices do not show a clear trend. Biomass increased from 1997 to 1999 has maintained almost constant values until 2013 and then decreased in 2014-2018. Redfish indices oscillate greatly over time, probably because the gear does not sample adequately aggregating pelagic species. There was a sharp increase in 2009 and since then until 2015, biomass fluctuated maintaining higher values than before 2009. In 2016 biomass dropped and increase again in 2017-2018 to the 2012 level. The 3N division comprises around the 90% of the total biomass in the last years. Good year classes have not been registered recently. Length distribution in thousands (abundance) by Division and year since 2002 is presented. Following the trend of the biomass, most of the abundance corresponds to Division 3N. Witch flounder is very scarce and its indices fluctuated throughout the series reaching the minimum value in 2014 and 2018, with an increasing trend in the middle time. Recruitment was quite good at the beginning of the series but poor in recent years

Biomass and length distribution for roughhead grenadier, thorny skate, white hake, squid and capelin from the surveys conducted by Spain in NAFO 3NO

Data for roughhead grenadier (Macrourus berglax), thorny skate (Amblyraja radiata) and white hake (Urophycis tenuis) from the Spanish Spring survey are presented. Abundance and biomass were estimated for roughhead grenadier and thorny skate for the period 1997-2019 and for white hake for the period 2001-2019. The length distribution is presented as numbers per haul stratified mean catches for the last five years (2015- 2019). The roughhead grenadier indices showed no discernible trend during the whole series, reaching a maximum in 2004 and a minimum in 2019. In 2017 and 2018, a quite good presence of small and medium lengths (1.5-19.5 cm) can be seen. Thorny skate indices follow a large oscillating trend, dropping in 2007 and has been since then more or less stables at a low level, reaching the minimum of the series by far in 2019. In 2017 there is a discrete presence of length between 12 and 18 cm. White hake indices were highest in 2001 and then showed an overall decreasing trend until 2008 with low values, generally increasing since then with some fluctuations. The 2019 biomass is the second lowest of the period studied. Small recruitment events were detected in 2004, 2012 and 2013, with individuals between 16-26 cm. In 2017 the highest numbers are at small lengths, between 20 and 24 cm, being around 34 cm in 2018. In 2019, the mode is around 8 cm. The estimated biomass of squid is inconstant and very low in general. There were no catches of squid during the 2002 and 2013-2015 surveys. In 2018 and 2019, a step increase in biomass was observed during the survey, being 5.5 and 7 times, respectively, the third value of the series in 2011. Length samples were taken in 2011, 2017 and 2019. The lengths range between 3.5 and 19 cm. Capelin biomass reached a maximum in 2012, decreasing sharply since then until 2017. In 2018 the index increased to a level similar to that in the early 2000s, decreasing slightly in 201

DC Network Indoor and Outdoor LED Lighting

LED lighting products have become a significant revolution in this technological sector. These components are, by nature, digital emitters created with semiconductor crystals that are powered with very low voltage and direct current (DC). Under these conditions, they have become one of the most relevant actors in the present tendency that is recovering the DC as the channel to transport and distribute energy and is reinforcing the photovoltaic (PV) panels as a relevant sustainable energy source that allows to improve the efficiencies of all types of lighting installations with the local self-generated energy. An analysis of the working principles of this component and the mechanism implemented for their control as lighting equipment to be powered with both conventional alternate current (AC) and DC is presented. A specific differentiation is done upon indoor and outdoor applications where new standards and regulations, specific technical procedures, and singular experimental project descriptions are detailed. The results expose the advantages and difficulties of implementation of this new DC paradigm, the main conclusion obtained up to this moment, and trends of future evolution

Biomass and length distribution for roughhead grenadier, thorny skate and white hake from the surveys conducted by Spain in NAFO 3NO

Data for roughhead grenadier (Macrourus berglax), thorny skate (Amblyraja radiata) and white hake (Urophycis tenuis) from the Spanish Spring survey are presented. Abundance and biomass were estimated for roughhead grenadier and thorny skate for the period 1997-2015 and for white hake for the period 2001-2015. The length distribution is presented as numbers per haul stratified mean catches for the last five years (2011-2015). The roughhead grenadier indices showed no discernible trend until 2012, reaching a maximum in 2004 - 2006 and afterwards stabilised at levels slightly higher than in the early years. In the last two years a decline was appreciated in the indices, reaching in 2014 one of the lowest values of the entire time-series, increasing again in 2015. Thorny skate indices follow a large oscillating trend, dropping in 2007 and being since then more or less stables at a low level, reaching the minimum of the series in 2014. White hake indices were highest in 2001 and then showed an overall decreasing trend until 2008 with low values. Indices increased since then until 2013 but declined again in 2014, increasing sligthly in 2015. A small recruitment event was detected in 2005 and in 2013, with individuals between 16 - 26 cm.Postprint0,000