2,919 research outputs found
Geoinformation mapping of modern gully erosion in the steppe region of the Russian Plain
Considering the linear erosion processes in the river basins slopes it can be noticed that the gully erosion is most intensively changing the relief, leading to the complete soil cover destruction, and is making the land not suitable for agricultural use. Due to the gullies' network shape and their large size, the satellite images allow noticing their representation. The study of the modern gully network was carried out in the steppe east of the Russian Plain on an area of more than 38000 km
Multi-component Transparent Conducting Oxides: Progress in Materials Modelling
Transparent conducting oxides (TCOs) play an essential role in modern
optoelectronic devices through their combination of electrical conductivity and
optical transparency. We review recent progress in our understanding of
multi-component TCOs formed from solid-solutions of ZnO, In2O3, Ga2O3 and
Al2O3, with a particular emphasis on the contributions of materials modelling,
primarily based on Density Functional Theory. In particular, we highlight three
major results from our work: (i) the fundamental principles governing the
crystal structures of multi-component oxide structures including (In2O3)(ZnO)n,
named IZO, and (In2O3)m(Ga2O3)l(ZnO)n, named IGZO; (ii) the relationship
between elemental composition and optical and electrical behaviour, including
valence band alignments; (iii) the high-performance of amorphous oxide
semiconductors. From these advances, the challenge of the rational design of
novel electroceramic materials is discussed.Comment: Part of a themed issue of Journal of Physics: Condensed Matter on
"Semiconducting Oxides". In Press (2011
Dielectric functions and collective excitations in MgB_2
The frequency- and momentum-dependent dielectric function as well as the energy loss function Im[-\protect{]} are calculated for intermetallic superconductor
by using two {\it ab initio} methods: the plane-wave pseudopotential method and
the tight-binding version of the LMTO method. We find two plasmon modes
dispersing at energies -8 eV and -22 eV. The high energy
plasmon results from a free electron like plasmon mode while the low energy
collective excitation has its origin in a peculiar character of the band
structure. Both plasmon modes demonstrate clearly anisotropic behaviour of both
the peak position and the peak width. In particular, the low energy collective
excitation has practically zero width in the direction perpendicular to boron
layers and broadens in other directions.Comment: 3 pages with 10 postscript figures. Submitted to PRB on May 14 200
Textured NiSe₂ Film: Bifunctional Electrocatalyst for Full Water Splitting at Remarkably Low Overpotential with High Energy Efficiency
Herein we have shown that electrodeposited NiSe2 can be used as a bifunctional electrocatalyst under alkaline conditions to split water at very low potential by catalyzing both oxygen evolution and hydrogen evolution reactions at anode and cathode, respectively, achieving a very high electrolysis energy efficiency exceeding 80% at considerably high current densities (100 mA cm-2). The OER catalytic activity as well as electrolysis energy efficiency surpasses any previously reported OER electrocatalyst in alkaline medium and energy efficiency of an electrolyzer using state-of-the-art Pt and RuO2 as the HER and OER catalyst, respectively. Through detailed electrochemical and structural characterization, we have shown that the enhanced catalytic activity is attributed to directional growth of the electrodeposited film that exposes a Ni-rich lattice plane as the terminating plane, as well as increased covalency of the selenide lattice which decreases the Ni(II) to Ni(III) oxidation potential. Thereby, the high efficiency along with extended stability makes NiSe2 as the most efficient water electrolyzer known to-date
Generalized stacking fault energetics and dislocation properties: compact vs. spread unit dislocation structures in TiAl and CuAu
We present a general scheme for analyzing the structure and mobility of
dislocations based on solutions of the Peierls-Nabarro model with a two
component displacement field and restoring forces determined from the ab-initio
generalized stacking fault energetics (ie., the so-called -surface).
The approach is used to investigate dislocations in L1 TiAl and CuAu;
predicted differences in the unit dislocation properties are explicitly related
with features of the -surface geometry. A unified description of
compact, spread and split dislocation cores is provided with an important
characteristic "dissociation path" revealed by this highly tractable scheme.Comment: 7 two columns pages, 2 eps figures. Phys. Rev. B. accepted November
199
Baby MIND: A magnetised spectrometer for the WAGASCI experiment
The WAGASCI experiment being built at the J-PARC neutrino beam line will
measure the difference in cross sections from neutrinos interacting with a
water and scintillator targets, in order to constrain neutrino cross sections,
essential for the T2K neutrino oscillation measurements. A prototype Magnetised
Iron Neutrino Detector (MIND), called Baby MIND, is being constructed at CERN
to act as a magnetic spectrometer behind the main WAGASCI target to be able to
measure the charge and momentum of the outgoing muon from neutrino charged
current interactions.Comment: Poster presented at NuPhys2016 (London, 12-14 December 2016). Title +
4 pages, LaTeX, 6 figure
Baby MIND Experiment Construction Status
Baby MIND is a magnetized iron neutrino detector, with novel design features,
and is planned to serve as a downstream magnetized muon spectrometer for the
WAGASCI experiment on the T2K neutrino beam line in Japan. One of the main
goals of this experiment is to reduce systematic uncertainties relevant to
CP-violation searches, by measuring the neutrino contamination in the
anti-neutrino beam mode of T2K. Baby MIND is currently being constructed at
CERN, and is planned to be operational in Japan in October 2017.Comment: Poster presented at NuPhys2016 (London, 12-14 December 2016). 4
pages, LaTeX, 7 figure
Synchronization of the Distributed Readout Frontend Electronics of the Baby MIND Detector
Baby MIND is a new downstream muon range detector for the WGASCI experiment. This article discusses the distributed readout system and its timing requirements. The paper presents the design of the synchronization subsystem and the results of its test
Baby MIND: A magnetized segmented neutrino detector for the WAGASCI experiment
T2K (Tokai-to-Kamioka) is a long-baseline neutrino experiment in Japan
designed to study various parameters of neutrino oscillations. A near detector
complex (ND280) is located 280~m downstream of the production target and
measures neutrino beam parameters before any oscillations occur. ND280's
measurements are used to predict the number and spectra of neutrinos in the
Super-Kamiokande detector at the distance of 295~km. The difference in the
target material between the far (water) and near (scintillator, hydrocarbon)
detectors leads to the main non-cancelling systematic uncertainty for the
oscillation analysis. In order to reduce this uncertainty a new
WAter-Grid-And-SCintillator detector (WAGASCI) has been developed. A magnetized
iron neutrino detector (Baby MIND) will be used to measure momentum and charge
identification of the outgoing muons from charged current interactions. The
Baby MIND modules are composed of magnetized iron plates and long plastic
scintillator bars read out at the both ends with wavelength shifting fibers and
silicon photomultipliers. The front-end electronics board has been developed to
perform the readout and digitization of the signals from the scintillator bars.
Detector elements were tested with cosmic rays and in the PS beam at CERN. The
obtained results are presented in this paper.Comment: In new version: modified both plots of Fig.1 and added one sentence
in the introduction part explaining Baby MIND role in WAGASCI experiment,
added information for the affiliation
Effects of C, Cu and Be substitutions in superconducting MgB2
Density functional calculations are used to investigate the effects of
partial substitutional alloying of the B site in MgB2 with C and Be alone and
combined with alloying of the Mg site with Cu. The effect of such substitutions
on the electronic structure, electron phonon coupling and superconductivity are
discussed. We find that Be substitution for B is unfavorable for
superconductivity as it leads to a softer lattice and weaker electron-phonon
couplings. Replacement of Mg by Cu leads to an increase in the stiffness and
doping level at the same time, while the carrier concentration can be
controlled by partial replacement of B by C. We estimate that with full
replacement of Mg by Cu and fractional substitution of B by C, Tc values of 50K
may be attainable.Comment: 5 pages, 4 figure
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