Polarisation and wavelength selective transmission through nanohole structures with multiple grating geometry

Excitation and localization of surface plasmon polariton modes in metal-dielectric structures can be utilized to construct nanophotonic materials and devices with tuneable optical dispersion. We present a selective polariton generator (SPG) device that demonstrates switching of light transmission based on surface plasmon antennae principles. This polarization-sensitive structure selectively generates and transports polaritons of a desired wavelength through subwavelength apertures. Two of these SPGs have been combined around a nanohole into a new, single device that allows polarization and wavelength selective switching of transmission. The multi-state operation is confirmed by experiment results

Regulamentação legal de empresas públicas nos países do sistema jurídico anglo-saxão

The article provides an overview of public corporation legal regulation in the Anglo-American law. The article defines the peculiarities of legal regulation of public companies in the USA and the UK. It also identifies requirements that public companies must meet. A comparative analysis was conducted concerning the organization and the activities of public and private companies. Similarities in the legal regulation of public companies in the United States and the United Kingdom are due to the fact that the American and British legal systems have the same historical roots.El artículo proporciona una descripción general de la regulación legal de las corporaciones públicas en la ley angloamericana. El artículo define las peculiaridades de la regulación legal de las empresas públicas en los Estados Unidos y el Reino Unido. También identifica los requisitos que deben cumplir las empresas públicas. Se realizó un análisis comparativo sobre la organización y las actividades de las empresas públicas y privadas. Las similitudes en la regulación legal de las empresas públicas en los Estados Unidos y el Reino Unido se deben al hecho de que los sistemas legales estadounidense y británico tienen las mismas raíces históricas.O artigo fornece uma visão geral da regulamentação legal de empresas públicas na lei anglo-americana. O artigo define as peculiaridades da regulamentação legal de empresas públicas nos EUA e no Reino Unido. Ele também identifica os requisitos que as empresas públicas devem atender. Uma análise comparativa foi realizada sobre a organização e as atividades de empresas públicas e privadas. As semelhanças na regulamentação legal das empresas públicas nos Estados Unidos e no Reino Unido devem-se ao fato de que os sistemas jurídicos americano e britânico têm as mesmas raízes históricas

Gallium plasmonic nanoantennas unveiling multiple kinetics of hydrogen sensing, storage, and spillover

Hydrogen is the key element to accomplish a carbon-free based economy. Here, the first evidence of plasmonic gallium (Ga) nanoantennas is provided as nanoreactors supported on sapphire (α-Al2O3) acting as direct plasmon-enhanced photocatalyst for hydrogen sensing, storage, and spillover. The role of plasmon-catalyzed electron transfer between hydrogen and plasmonic Ga nanoparticle in the activation of those processes is highlighted, as opposed to conventional refractive index-change-based sensing. This study reveals that, while temperature selectively operates those various processes, longitudinal (LO-LSPR) and transverse (TO-LSPR) localized surface plasmon resonances of supported Ga nanoparticles open selectivity of localized reaction pathways at specific sites corresponding to the electromagnetic hot-spots. Specifically, the TO-LSPR couples light into the surface dissociative adsorption of hydrogen and formation of hydrides, whereas the LO-LSPR activates heterogeneous reactions at the interface with the support, that is, hydrogen spillover into α-Al2O3 and reverse-oxygen spillover from α-Al2O3. This Ga-based plasmon-catalytic platform expands the application of supported plasmon-catalysis to hydrogen technologies, including reversible fast hydrogen sensing in a timescale of a few seconds with a limit of detection as low as 5 ppm and in a broad temperature range from room-temperature up to 600 °C while remaining stable and reusable over an extended period of time.The authors thank all of the students and colleagues in their groups who were actively involved with nanoparticles research. M.L., Y.G., and F.M. have received funding from the European Union's Horizon 2020 Research and Innovation Program under Grant Agreement No. 899598—PHEMTRONICS. F.M. acknowledges MINECO (Spanish Ministry of Economy and Competitiveness, project PGC2018-096649-B-100)

Science results from the imaging Fourier transform spectrometer SpIOMM

SpIOMM is an imaging Fourier transform spectrometer designed to obtain the visible range (350 to 850 nm) spectrum of every light source in a circular field of view of 12 arcminutes in diameter. It is attached to the 1.6-m telescope of the Observatoire du Mont Megantic in southern Quebec. We present here some results of three successful observing runs in 2007, which highlight SpIOMMs capabilities to map emission line objects over a very wide field of view and a broad spectral range. In particular, we discuss data cubes from the planetary nebula M27, the supernova remnants NGC 6992 and M1, the barred spiral galaxy NGC7479, as well as Stephans quintet, an interacting group of galaxies.Comment: 10 pages, 7 figures, to appear in "Ground-based and Airborne Instrumentation for Astronomy II", SPIE conference, Marseille, 23-28 June 200

FILLER WEAR TEST FACILITY UNDER ROLLING FRICTION

Studies on the filler wear under the heavy loading by the hardened surface rolling friction have been carried out on the special facility using test pieces built-up with the abutting inductor through the continuous sequential melting of the prefixed batch layer

Enhancing the critical current of YBa2Cu3O7 thin films by substrate nanoengineering

The critical current density, J c, can be increased by introducing defects throughout YBa 2Cu 3O 7 superconducting thin films. We propose a new approach of substrate nanoengineering to produce well-controlled defects. LaAlO 3 substrates have been ion-etched with different 34 nm deep patterns prior to the deposition of the films. An annealing step at 1000 °C after substrate etching has been undertaken to negate the Ar-ion damage to the surface. The J c of the so-prepared samples measured at different temperatures has been compared to thin films deposited on plain substrates at the same time. In general, an increase in J c is observed across all temperatures and fields as a result of both patterning and annealing. In particular, at zero field and 85 K, the largest enhancement of \u3e 40% has been recorded for circle and triangle patterns. This new substrate nanoengineering technique is very promising for flux trapping of superconducting devices, particularly because an increase to critical current ( I c) also occurs. Further optimization of depth, size, and shape of the patterns is expected to produce further improvements to J c

Large, controllable spikes of magnetoresistance in La2/3Ca 1/3MnO3/SrTiO3 superlattices

We have investigated superlattices consisting of up to 30 epitaxial nanomultilayers (3-7 nm thick) of ferromagnetic La2/3Ca 1/3MnO3 (LCMO) and insulating SrTiO3 (STO) hybrids. The superlattices demonstrate dramatic shifts of Curie temperature, indicating the possibility of its tunability. The metal-insulator transition (MIT) has been observed around 140 K. Below the MIT temperature, the superlattices have shown sharp drops of resistivity, facilitating the largest and sharpest magnetoresistance peaks (\u3e2000%) ever observed in LCMO films and superlattices at low temperatures. The observed experimental results can be explained in the frame of the phase separation model in manganites with well-organized structures. The results of magnetic and transport measurements of such hybrid structures are discussed, indicating a magnetodielectric effect in STO interlayers. The magnetic and transport properties of the superlattices are shown to be technology-dependent, experiencing dimensional transitions, which enables the creation of structures with prescribed magnetoresistance characteristics for a broad range of applications