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A series of short events, called A-phases, can be observed in the human electroencephalogram during NREM sleep. These events can be classified in three groups (A1, A2 and A3) according to their spectral contents, and are thought to play a role in the transitions between the different sleep stages. A-phase detection and classification is usually performed manually by a trained expert, but it is a tedious and time-consuming task. In the past two decades, various researchers have designed algorithms to automatically detect and classify the A-phases with varying degrees of success, but the problem remains open. In this paper, a different approach is proposed: instead of attempting to design a general classifier for all subjects, we propose to train ad-hoc classifiers for each subject using as little data as possible, in order to drastically reduce the amount of time required from the expert. The proposed classifiers are based on deep convolutional neural networks using the log-spectrogram of the EEG signal as input data. Results are encouraging, achieving average accuracies of 80.31% when discriminating between A-phases and non A-phases, and 71.87% when classifying among A-phase sub-types, with only 25% of the total A-phases used for training. When additional expert-validated data is considered, the sub-type classification accuracy increases to 78.92%. These results show that a semi-automatic annotation system with assistance from an expert could provide a better alternative to fully automatic classifiers., Comment: 19 pages, 5 figures, 4 tables

Unintended impurities, such as oxygen, can significantly influence the growth morphology, structure, and mechanical properties of many materials. Therefore, we study the origin and impact of oxygen impurities (between ~ 0.3 and 1.3 at.%) on sputtered Ti1‐xAlxN thin films by using targets with three different oxygen impurity levels and modifying the deposition conditions such as the base pressure. The oxygen impurity content of our coatings was always (by around ≥ 0.1 at.%) above that of the target used. Detailed atom probe tomography as well as secondary ion mass spectroscopy indicate a homogeneous distribution of the oxygen impurities across our face centred cubic structured Ti0.50Al0.50N coatings. Except for higher oxygen levels at the interface to the substrate, which is more pronounced when the target is not sputter‐cleaned prior to the deposition, and at the coating surface, there are no detectable oxygen variations at the grain or column boundaries. Based on our results we can conclude that the growth orientation of our coatings changes from random (for the cleanest coatings with ~ 0.3 at.% O) to pronounced 111 (for the coatings with the highest oxygen content of ~ 1.3 at.% O) with increasing oxygen impurity content. Thereby, also the coherently diffracting crystallite sizes increase from around 35 to 100 nm, the growth morphology changes from dense columnar grains to more open, porous columnar grains, and thus the hardness decreases from around 35 to 20 GPa. Our study highlights the importance of well‐defined deposition conditions and high quality targets for developing high quality thin films.

The authors investigate the interdiffusion damage of Cu/TiN stacks deposited on Si(001) substrates by low-temperature unbalanced direct current magnetron sputtering. Pristine and diffusion-annealed samples are examined by x-ray diffraction, four-point-probe resistivity measurements, scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atom probe tomography. Two relevant diffusion processes are identified. The local diffusion of Cu through defects and grain boundaries in the TiN layer leads to the formation of the eta -Cu3Si phase at the barrier/substrate interface. Three-dimensional reconstructions obtained by atom probe tomography additionally reveal the outward diffusion of Si atoms from the substrate through the TiN bulk toward the Cu top layer, eventually also resulting in the formation of a discontinuous Cu3Si surface layer. (C) 2016 American Vacuum Society., Funding Agencies|Austrian Federal Government (Bundesministerium fur Verkehr, Innovation und Technologie); Austrian Federal Government (Bundesministerium fur Wirtschaft, Familie und Jugend); Styrian and the Tyrolean Provincial Government; Swedish Research Council [2013-4018]; Knut and Alice Wallenberg Foundation for the Ultra Electron Microscopy Laboratory at Linkoping University

TiN/Cu bilayers were grown by unbalanced DC magnetron sputter deposition on (001)-oriented MgO substrates. Pole figures and electron back-scatter diffraction orientation maps indicate that both layers in the as-deposited state are single-crystalline with a cube-on-cube epitaxial relationship with the substrate. This is confirmed by selected area electron diffraction patterns. To study the efficiency of the TiN barrier layer against in-diffusion of Cu, we annealed samples at 900 degrees C for 1 h in vacuum and at 1000 degrees C for 12 h in Ar atmosphere. The single-crystalline structure of the TiN layer is stable up to annealing temperatures of 1000 degrees C as shown by high resolution transmission electron microscopy. While no Cu diffusion was evident after annealing at 900 degrees C, scanning transmission electron microscopy images and energy-dispersive X-ray spectrometry maps show a uniform diffusion layer of about 12 nm after annealing at 1000 degrees C for 12 h. Concentration depth profiles obtained from 3D atom probe tomography reconstructions confirm these findings and reveal that the TiN film is slightly substoichiometric with a N/Ti ratio of 0.92. Considering this composition, we propose a lattice diffusion mechanism of Cu in TiN via the formation of Cu-N vacancy complexes. The excellent diffusion barrier properties of single-crystalline TiN are further attributed to the lack of fast diffusion paths such as grain boundaries., Funding Agencies|Austrian Federal Government; Bundesministerium fur Verkehr, Innovation und Technologie; Bundesministerium fur Wirtschaft, Familie und Jugend; Styrian and the Tyrolean Provincial Government; Swedish Research Council [2013-4018]; Knut and Alice Wallenberg Foundation for the Electron Microscopy Laboratory at Linkoping University

TiN/Cu bilayers were grown by unbalanced DC magnetron sputter deposition on (001)-oriented MgO substrates. Pole figures and electron back-scatter diffraction orientation maps indicate that both layers in the as-deposited state are single-crystalline with a cube-on-cube epitaxial relationship with the substrate. This is confirmed by selected area electron diffraction patterns. To study the efficiency of the TiN barrier layer against in-diffusion of Cu, we annealed samples at 900 degrees C for 1 h in vacuum and at 1000 degrees C for 12 h in Ar atmosphere. The single-crystalline structure of the TiN layer is stable up to annealing temperatures of 1000 degrees C as shown by high resolution transmission electron microscopy. While no Cu diffusion was evident after annealing at 900 degrees C, scanning transmission electron microscopy images and energy-dispersive X-ray spectrometry maps show a uniform diffusion layer of about 12 nm after annealing at 1000 degrees C for 12 h. Concentration depth profiles obtained from 3D atom probe tomography reconstructions confirm these findings and reveal that the TiN film is slightly substoichiometric with a N/Ti ratio of 0.92. Considering this composition, we propose a lattice diffusion mechanism of Cu in TiN via the formation of Cu-N vacancy complexes. The excellent diffusion barrier properties of single-crystalline TiN are further attributed to the lack of fast diffusion paths such as grain boundaries., Funding Agencies|Austrian Federal Government; Bundesministerium fur Verkehr, Innovation und Technologie; Bundesministerium fur Wirtschaft, Familie und Jugend; Styrian and the Tyrolean Provincial Government; Swedish Research Council [2013-4018]; Knut and Alice Wallenberg Foundation for the Electron Microscopy Laboratory at Linkoping University

TiN/Cu bilayers were grown by unbalanced DC magnetron sputter deposition on (001)-oriented MgO substrates. Pole figures and electron back-scatter diffraction orientation maps indicate that both layers in the as-deposited state are single-crystalline with a cube-on-cube epitaxial relationship with the substrate. This is confirmed by selected area electron diffraction patterns. To study the efficiency of the TiN barrier layer against in-diffusion of Cu, we annealed samples at 900 degrees C for 1 h in vacuum and at 1000 degrees C for 12 h in Ar atmosphere. The single-crystalline structure of the TiN layer is stable up to annealing temperatures of 1000 degrees C as shown by high resolution transmission electron microscopy. While no Cu diffusion was evident after annealing at 900 degrees C, scanning transmission electron microscopy images and energy-dispersive X-ray spectrometry maps show a uniform diffusion layer of about 12 nm after annealing at 1000 degrees C for 12 h. Concentration depth profiles obtained from 3D atom probe tomography reconstructions confirm these findings and reveal that the TiN film is slightly substoichiometric with a N/Ti ratio of 0.92. Considering this composition, we propose a lattice diffusion mechanism of Cu in TiN via the formation of Cu-N vacancy complexes. The excellent diffusion barrier properties of single-crystalline TiN are further attributed to the lack of fast diffusion paths such as grain boundaries., Funding Agencies|Austrian Federal Government; Bundesministerium fur Verkehr, Innovation und Technologie; Bundesministerium fur Wirtschaft, Familie und Jugend; Styrian and the Tyrolean Provincial Government; Swedish Research Council [2013-4018]; Knut and Alice Wallenberg Foundation for the Electron Microscopy Laboratory at Linkoping University

TiN/Cu bilayers were grown by unbalanced DC magnetron sputter deposition on (001)-oriented MgO substrates. Pole figures and electron back-scatter diffraction orientation maps indicate that both layers in the as-deposited state are single-crystalline with a cube-on-cube epitaxial relationship with the substrate. This is confirmed by selected area electron diffraction patterns. To study the efficiency of the TiN barrier layer against in-diffusion of Cu, we annealed samples at 900 degrees C for 1 h in vacuum and at 1000 degrees C for 12 h in Ar atmosphere. The single-crystalline structure of the TiN layer is stable up to annealing temperatures of 1000 degrees C as shown by high resolution transmission electron microscopy. While no Cu diffusion was evident after annealing at 900 degrees C, scanning transmission electron microscopy images and energy-dispersive X-ray spectrometry maps show a uniform diffusion layer of about 12 nm after annealing at 1000 degrees C for 12 h. Concentration depth profiles obtained from 3D atom probe tomography reconstructions confirm these findings and reveal that the TiN film is slightly substoichiometric with a N/Ti ratio of 0.92. Considering this composition, we propose a lattice diffusion mechanism of Cu in TiN via the formation of Cu-N vacancy complexes. The excellent diffusion barrier properties of single-crystalline TiN are further attributed to the lack of fast diffusion paths such as grain boundaries., Funding Agencies|Austrian Federal Government; Bundesministerium fur Verkehr, Innovation und Technologie; Bundesministerium fur Wirtschaft, Familie und Jugend; Styrian and the Tyrolean Provincial Government; Swedish Research Council [2013-4018]; Knut and Alice Wallenberg Foundation for the Electron Microscopy Laboratory at Linkoping University

Dense single-crystal and polycrystalline TiN/Cu stacks were prepared by unbalanced DC magnetron sputter deposition at a substrate temperature of 700 °C and a pulsed bias potential of -100 V. The microstructural variation was achieved by using two different substrate materials, MgO(001) and thermally oxidized Si(001), respectively. Subsequently, the stacks were subjected to isothermal annealing treatments at 900 °C for 1 h in high vacuum to induce the diffusion of Cu into the TiN. The performance of the TiN diffusion barrier layers was evaluated by cross-sectional transmission electron microscopy in combination with energy-dispersive X-ray spectrometry mapping and atom probe tomography. No Cu penetration was evident in the single-crystal stack up to annealing temperatures of 900 °C, due to the low density of line and planar defects in single-crystal TiN. However, at higher annealing temperatures when diffusion becomes more prominent, density-functional theory calculations predict a stoichiometry-dependent atomic diffusion mechanism of Cu in bulk TiN, with Cu diffusing on the N sublattice for the experimental N/Ti ratio. In comparison, localized diffusion of Cu along grain boundaries in the columnar polycrystalline TiN barriers was detected after the annealing treatment. The maximum observed diffusion length was approximately 30 nm, yielding a grain boundary diffusion coefficient of the order of 10‑16 cm2s-1 at 900 °C. This is 10 to 100 times less than for comparable underdense polycrystalline TiN coatings deposited without external substrate heating or bias potential. The combined numerical and experimental approach presented in this paper enables the contrasting juxtaposition of diffusion phenomena and mechanisms in two TiN coatings, which differ from each other only in the presence of grain boundaries.

TiN/Cu bilayers were grown by unbalanced DC magnetron sputter deposition on (001)-oriented MgO substrates. Pole figures and electron back-scatter diffraction orientation maps indicate that both layers in the as-deposited state are single-crystalline with a cube-on-cube epitaxial relationship with the substrate. This is confirmed by selected area electron diffraction patterns. To study the efficiency of the TiN barrier layer against in-diffusion of Cu, we annealed samples at 900 degrees C for 1 h in vacuum and at 1000 degrees C for 12 h in Ar atmosphere. The single-crystalline structure of the TiN layer is stable up to annealing temperatures of 1000 degrees C as shown by high resolution transmission electron microscopy. While no Cu diffusion was evident after annealing at 900 degrees C, scanning transmission electron microscopy images and energy-dispersive X-ray spectrometry maps show a uniform diffusion layer of about 12 nm after annealing at 1000 degrees C for 12 h. Concentration depth profiles obtained from 3D atom probe tomography reconstructions confirm these findings and reveal that the TiN film is slightly substoichiometric with a N/Ti ratio of 0.92. Considering this composition, we propose a lattice diffusion mechanism of Cu in TiN via the formation of Cu-N vacancy complexes. The excellent diffusion barrier properties of single-crystalline TiN are further attributed to the lack of fast diffusion paths such as grain boundaries., Funding Agencies|Austrian Federal Government; Bundesministerium fur Verkehr, Innovation und Technologie; Bundesministerium fur Wirtschaft, Familie und Jugend; Styrian and the Tyrolean Provincial Government; Swedish Research Council [2013-4018]; Knut and Alice Wallenberg Foundation for the Electron Microscopy Laboratory at Linkoping University

The conservation of humpback dolphins, distributed in coastal waters of the Indo-West Pacific and eastern Atlantic Oceans, has been hindered by a lack of understanding about the number of species in the genus (Sousa) and their population structure. To address this issue, we present a combined analysis of genetic and morphologic data collected from beach-cast, remote-biopsied and museum specimens from throughout the known Sousa range. We extracted genetic sequence data from 235 samples from extant populations and explored the mitochondrial control region and four nuclear introns through phylogenetic, population-level and population aggregation frameworks. In addition, 180 cranial specimens from the same geographical regions allowed comparisons of 24 morphological characters through multivariate analyses. The genetic and morphological data showed significant and concordant patterns of geographical segregation, which are typical for the kind of demographic isolation displayed by species units, across the Sousa genus distribution range. Based on our combined genetic and morphological analyses, there is convincing evidence for at least four species within the genus (S.teuszii in the Atlantic off West Africa, S.plumbea in the central and western Indian Ocean, S.chinensis in the eastern Indian and West Pacific Oceans, and a new as-yet-unnamed species off northern Australia)., AuthorCount:18