Search results for "INTERFACE"
showing 10 items of 2139 documents
Simplified spiking neural network architecture and STDP learning algorithm applied to image classification
2015
Spiking neural networks (SNN) have gained popularity in embedded applications such as robotics and computer vision. The main advantages of SNN are the temporal plasticity, ease of use in neural interface circuits and reduced computation complexity. SNN have been successfully used for image classification. They provide a model for the mammalian visual cortex, image segmentation and pattern recognition. Different spiking neuron mathematical models exist, but their computational complexity makes them ill-suited for hardware implementation. In this paper, a novel, simplified and computationally efficient model of spike response model (SRM) neuron with spike-time dependent plasticity (STDP) lear…
Spin relaxation in Cu and Al spin conduits
2014
We study the spin relaxation in Al and Cu spin conduits embedded in non-local spin valve nanostructures. Measuring the key spin transport properties, we determine the spin and charge diffusion constants as well as the spin flip time. By varying the temperature, we find that the maximum of the non-local spin resistance change occurs at finite temperatures with a clear difference between Al and Cu. In particular, we find that the maximum of the non-local spin signal in Al is less pronounced and occurs at lower temperatures compared to Cu suggesting that the self-passivating Al surface plays a role. Having fabricated devices with both materials in identical processes, we can attribute the diff…
First-order and tricritical wetting transitions in the two-dimensional Ising model caused by interfacial pinning at a defect line
2014
We present a study of the critical behavior of the Blume-Capel model with three spin states (S=±1,0) confined between parallel walls separated by a distance L where competitive surface magnetic fields act. By properly choosing the crystal field (D), which regulates the density of nonmagnetic species (S=0), such that those impurities are excluded from the bulk (where D=) except in the middle of the sample [where DM(L/2)≠], we are able to control the presence of a defect line in the middle of the sample and study its influence on the interface between domains of different spin orientations. So essentially we study an Ising model with a defect line but, unlike previous work where defect lines …
Atomic, electronic and thermodynamic properties of cubic and orthorhombic LaMnO3 surfaces
2009
We studied in detail the atomic and electronic structure of the LaMnO3 surfaces, in both cubic and orthorhombic phases, combining GGA-plane wave approach, as implemented into the VASP-4.6.19 computer code, with a slab model. These studies are complemented by a thermodynamic analysis of the surface stability at different gas pressures and temperatures. The obtained results are compared with similar studies for other ABO3-perovskites. 2008 Elsevier B.V. All rights reserved. The ABO3-type perovskite manganites and cobaltates (A = La, Sr, Ca; B = Mn, Co) are important functional materials with numerous high-tech applications [1]. Some of them require understanding and control surface properties…
Large Conductance Switching in a Single-Molecule Device through Room Temperature Spin-Dependent Transport
2016
Controlling the spin of electrons in nanoscale electronic devices is one of the most promising topics aiming at developing devices with rapid and high density information storage capabilities. The interface magnetism or spinterface resulting from the interaction between a magnetic molecule and a metal surface, or vice versa, has become a key ingredient in creating nanoscale molecular devices with novel functionalities. Here, we present a single-molecule wire that displays large (>10000%) conductance switching by controlling the spin-dependent transport under ambient conditions (room temperature in a liquid cell). The molecular wire is built by trapping individual spin crossover Fe-II comple…
Fabrication of Chemically Tunable, Hierarchically Branched Polymeric Nanostructures by Multi-branched Anodic Aluminum Oxide Templates
2016
In this paper, a template-assisted replication method is demonstrated for the fabrication of hierarchically branched polymeric nanostructures composed of post-modifiable poly(pentafluorophenyl acrylate). Anodic aluminum oxide templates with various shapes of hierarchically branched pores are fabricated by an asymmetric two-step anodization process. The hierarchical polymeric nanostructures are obtained by infiltration of pentafluorophenyl acrylate with a cross-linker and photoinitiator, followed by polymerization and selective removal of the template. Furthermore, the nanostructures containing reactive pentafluorophenyl ester are modified with spiropyran amine via post-polymerization modifi…
Building Digital Government by XML
2005
Continuing innovations in information and communication technologies offer powerful tools for building digital government but, at the same time, in many environments they have lead into a number of heterogeneous, expensive, and inconsistent solutions. XML offers a common metalanguage and terminology to develop means for system and data integration, and for gradual transfer to more consistent formats in information assets. The paper describes ways for the use of XML in public administration and gives examples of the use, particularly, in Finland. The paper introduces XML standardization levels and types in public administration. Experiences of the long-term standardization of the Finnish par…
Effect of Cholesterol on Electrostatics in Lipid−Protein Films of a Pulmonary Surfactant
2010
We report the changes in the electrical properties of the lipid-protein film of pulmonary surfactant produced by excess cholesterol. Pulmonary surfactant (PS) is a complex lipid-protein mixture that forms a molecular film at the interface of the lung's epithelia. The defined molecular arrangement of the lipids and proteins of the surfactant film gives rise to the locally highly variable electrical surface potential of the interface, which becomes considerably altered in the presence of cholesterol. With frequency modulation Kelvin probe force microscopy (FM-KPFM) and force measurements, complemented by theoretical analysis, we showed that excess cholesterol significantly changes the electri…
Principle and analytical applications of resonance lonization mass spectrometry
1989
Resonance ionization mass spectrometry (RIMS) is a very sensitive analytical technique for the detection of trace elements. This method is based on the excitation and ionization of atoms with resonant laser light followed by mass analysis. It allows element and, in some cases, isotope selective ionization and is applicable to most of the elements of the periodic table. A high selectivity can be achieved by applying three step photoionization of the elements under investigation and an additional mass separation for an unambiguous isotope assignment. An effective facility for resonance ionization mass spectrometry consists of three dye lasers which are pumped by two copper vapor lasers and of…
A static SIMS study of superficial reactions (O2, (CN)2) on silver
1998
Abstract The exposure of silver surfaces to oxygen under about 10 −6 mbar at room temperature was studied mainly by secondary ion mass spectrometry (SIMS) used in a static mode. No reactivity of oxygen appeared under these exposure conditions in accordance with previous works. No modifications in the AES spectra, but an unexpected and huge increase in the intensities of secondary ions such as CN − , CNO − , Ag(CN) − 2 , Ag 2 CN + were observed. Different experiments were performed in order to specify the origin of this unexpected reaction in presence of pure oxygen. Moreover, exposures to pure (CN) 2 and to a mixture of cyanogen and oxygen were performed in order to compare the reactivity o…