13 research outputs found
Highly absorbing black Mg and rare-earth-Mg switchable mirrors
Apart from a reflecting and a transparent state, rare-earth-Mg alloys (RE-Mg) exhibit also a highly absorbing, black state during loading with hydrogen. The occurrence of such a black state is due to the disproportionation into subwavelength size RE
Нелинейная нетерова краевая задача в критическом случае
Знайдено необхiднi та достатнi умови iснування розв’язкiв слабко нелiнiйної нетерової крайової задачi для системи звичайних диференцiальних рiвнянь у критичному випадку.We construct necessary and sufficient conditions for the existence of the solution of a Noether weakly nonlinear boundary-value problem for a system of ordinary differential equations in the critical case
COMMISSION OF THE EUROPEAN COMMUNITIES. Draft DECISION OF THE REPRESENTATIVES OF THE GOVERNMENTS OF THE MEMBER STATES OF THE EUROPEAN COAL AND STEEL COMMUNITY. MEETING WITHIN THE COUNCIL. modifying Decision 92/470/ECSC concerning certain technical modalities in connection with the application of Decision 92/285/ECSC prohibiting trade between the European Coal and Steel Community and the Republics of Serbia and Montenegro. Proposal for a COUNCIL REGULATION (EEC) modifying Regulation (EEC) No 2656/92 concerning certain technical modalities in connection with the application of Regulation (EEC) No 1432/92 prohibiting trade between the European Economic Community and the Republics of Serbia and Montenegro (presented by the Commission). COM (92) 485 final, 18 December 1992
Optical properties of MgH2 measured in situ in a novel gas cell for ellipsometry/spectrophotometry
The dielectric properties of alpha-MgH2 are investigated in the photon energy
range between 1 and 6.5 eV. For this purpose, a novel sample configuration and
experimental setup are developed that allow both optical transmission and
ellipsometric measurements of a transparent thin film in equilibrium with
hydrogen. We show that alpha-MgH2 is a transparent, colour neutral insulator
with a band gap of 5.6 +/- 0.1 eV. It has an intrinsic transparency of about
80% over the whole visible spectrum. The dielectric function found in this work
confirms very recent band structure calculations using the GW approximation by
Alford and Chou [J.A. Alford and M.Y. Chou (unpublished)]. As Pd is used as a
cap layer we report also the optical properties of PdHx thin films.Comment: REVTeX4, 15 pages, 12 figures, 5 table
Electrochromism of Mg-Ni hydride switchable mirrors
Switchable mirrors have so far been made of rare-earth and rare-earth-magnesium based metal-hydrides. In this investigation we study Mg-Ni-hydrides, which have been shown by Richardson et al. to exhibit switchable properties similar to those of the rare-earth hydrides. Cyclic voltammetry on MgzNiHx samples with 0.8 < z < 3.7 shows that addition of one Mg atom per Mg2Ni gives the best ab/desorption kinetics for hydrogen. X-ray diffraction reveals a structural change as hydrogen is absorbed. The metal-insulator transition is confirmed with simultaneous resistivity measurements. A pressure-composition isotherm of Mg2NiHx is also determined electrochemically. Optical spectrometry during gas loading gives an optical band gap of 1.6 eV for Mg2NiH4. This gap increases with increasing Mg content in a way similar to that of the Mg-doped rare-earth hydrides
Thermochromic metal-hydride bilayer devices
The temperature dependent optical properties of certain thin films are used in so-called thermochromic devices. As an alternative to a single layer of, e.g. V
The properties of pulsed laser deposited YH2 films for switchable devices
In-situ deposited Y
Self-Organized Layered Hydrogenation in Black Mg2NiHx Switchable Mirrors
In addition to a mirrorlike (Mg2Ni) and a transparent (Mg2NiH4) state, thin films of Mg2NiHx exhibit a remarkable black state with low reflection over the entire visible spectrum, essentially zero transmission and a low electrical resistivity. Such a black state is not explicable for a homogeneous layer since a large absorption coefficient always yields substantial reflection. We show that it results from a self-organized and reversible double layering of metallic Mg2NiH0.3 and semiconducting Mg2NiH4.
Structural, optical and electronic properties of LaMgHx switchable mirrors.
Structural, optical and electronic properties of lanthanum magnesium alloy thin films are studied in situ in real time during hydrogenation. X-ray data show that the as-deposited films contain the intermetallic phase LaMg with CsCl structure as well as fcc β-La and fcc La