224 research outputs found
Ethanol Sensing Performances of Zinc-doped Copper Oxide Nano-crystallite Layers
The synthesis via chemical solutions (aqueous) (SCS) wet route is a low-temperature and cost-effective growth technique of high crystalline quality oxide semiconductors films. Here we report on morphology, chemical composition, structure and ethanol sensing performances of a device prototype based on zincdoped copper oxide nanocrystallite layer. By thermal annealing in electrical furnace for 30 min at temperatures higher than 550 ˚C, as-deposited zinc doped Cu2O samples are converted to tenorite, ZnxCu1-xOy, (x=1.3wt%) that demonstrate higher ethanol response than sensor structures based on samples treated at 450 ˚C. In case of the specimens after post-growth treatment at 650 ˚C was found an ethanol gas response
of about 79 % and 91 % to concentrations of 100 ppm and 500 ppm, respectively, at operating temperature of 400 ˚C in air
Building nonparametric -body force fields using Gaussian process regression
Constructing a classical potential suited to simulate a given atomic system
is a remarkably difficult task. This chapter presents a framework under which
this problem can be tackled, based on the Bayesian construction of
nonparametric force fields of a given order using Gaussian process (GP) priors.
The formalism of GP regression is first reviewed, particularly in relation to
its application in learning local atomic energies and forces. For accurate
regression it is fundamental to incorporate prior knowledge into the GP kernel
function. To this end, this chapter details how properties of smoothness,
invariance and interaction order of a force field can be encoded into
corresponding kernel properties. A range of kernels is then proposed,
possessing all the required properties and an adjustable parameter
governing the interaction order modelled. The order best suited to describe
a given system can be found automatically within the Bayesian framework by
maximisation of the marginal likelihood. The procedure is first tested on a toy
model of known interaction and later applied to two real materials described at
the DFT level of accuracy. The models automatically selected for the two
materials were found to be in agreement with physical intuition. More in
general, it was found that lower order (simpler) models should be chosen when
the data are not sufficient to resolve more complex interactions. Low GPs
can be further sped up by orders of magnitude by constructing the corresponding
tabulated force field, here named "MFF".Comment: 31 pages, 11 figures, book chapte
Saliency Benchmarking Made Easy: Separating Models, Maps and Metrics
Dozens of new models on fixation prediction are published every year and
compared on open benchmarks such as MIT300 and LSUN. However, progress in the
field can be difficult to judge because models are compared using a variety of
inconsistent metrics. Here we show that no single saliency map can perform well
under all metrics. Instead, we propose a principled approach to solve the
benchmarking problem by separating the notions of saliency models, maps and
metrics. Inspired by Bayesian decision theory, we define a saliency model to be
a probabilistic model of fixation density prediction and a saliency map to be a
metric-specific prediction derived from the model density which maximizes the
expected performance on that metric given the model density. We derive these
optimal saliency maps for the most commonly used saliency metrics (AUC, sAUC,
NSS, CC, SIM, KL-Div) and show that they can be computed analytically or
approximated with high precision. We show that this leads to consistent
rankings in all metrics and avoids the penalties of using one saliency map for
all metrics. Our method allows researchers to have their model compete on many
different metrics with state-of-the-art in those metrics: "good" models will
perform well in all metrics.Comment: published at ECCV 201
The H1 Forward Proton Spectrometer at HERA
The forward proton spectrometer is part of the H1 detector at the HERA
collider. Protons with energies above 500 GeV and polar angles below 1 mrad can
be detected by this spectrometer. The main detector components are
scintillating fiber detectors read out by position-sensitive photo-multipliers.
These detectors are housed in so-called Roman Pots which allow them to be moved
close to the circulating proton beam. Four Roman Pot stations are located at
distances between 60 m and 90 m from the interaction point.Comment: 20 pages, 10 figures, submitted to Nucl.Instr.and Method
Анализ эффективности деятельности предприятия сферы услуг в современных условиях
В данной работе исследуются финансовые результаты деятельности предприятия сферы услуг.
Цель работы заключается в проведении анализа эффективности деятельности предприятия, оказывающего услуги в сфере гостиничного бизнеса и общественного питания, согласно специфике практических данных.
В процессе исследования проводился анализ экономических показателей эффективности деятельности предприятия.This paper examines the financial performance of the enterprise services.
The purpose of the work is to conduct an analysis of the effectiveness of the company, providing services in the hotel business and catering, according to the specifics of practical data.
In the process of the study, an analysis of the economic performance indicators of the enterprise was carried out
The first search for bosonic super-WIMPs with masses up to 1 MeV/c with GERDA
We present the first search for bosonic super-WIMPs as keV-scale dark matter
candidates performed with the GERDA experiment. GERDA is a neutrinoless
double-beta decay experiment which operates high-purity germanium detectors
enriched in Ge in an ultra-low background environment at the Laboratori
Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for
pseudoscalar and vector particles in the mass region from 60 keV/c to 1
MeV/c. No evidence for a dark matter signal was observed, and the most
stringent constraints on the couplings of super-WIMPs with masses above 120
keV/c have been set. As an example, at a mass of 150 keV/c the most
stringent direct limits on the dimensionless couplings of axion-like particles
and dark photons to electrons of and
at 90% credible interval,
respectively, were obtained.Comment: 6 pages, 3 figures, submitted to Physical Review Letters, added list
of authors, updated ref. [21
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