1,405 research outputs found
Deformations of the Boson Representation and its Subalgebras
The boson representation of the sp(4,R) algebra and two distinct deformations
of it, are considered, as well as the compact and noncompact subalgebras of
each. The initial as well as the deformed representations act in the same Fock
space.
One of the deformed representation is based on the standard q-deformation of
the boson creation and annihilation operators. The subalgebras of sp(4,R)
(compact u(2) and three representations of the noncompact u(1,1) are also
deformed and are contained in this deformed algebra. They are reducible in the
action spaces of sp(4,R) and decompose into irreducible representations.
The other deformed representation, is realized by means of a transformation
of the q-deformed bosons into q-tensors (spinor-like) with respect to the
standard deformed su(2). All of its generators are deformed and have
expressions in terms of tensor products of spinor-like operators. In this case,
an other deformation of su(2) appears in a natural way as a subalgebra and can
be interpreted as a deformation of the angular momentum algebra so(3). Its
representation is reducible and decomposes into irreducible ones that yields a
complete description of the same
CHARACTERIZATION OF RF AND DC MAGNETRON REACTIVE SPUTTERED TiO 2 THIN FILMS FOR GAS SENSORS
This study presents the technology for prep
aring and characterization of titanium oxide
thin films with proper
ties suitable for gas sensors. For
preparing the samples the reactive
radio frequency (RF) and direct current (DC) magnetron sputtering methods were used.
The composition and microstructure of the films were studied by X-ray photoelectron
spectroscopy (XPS), X-ray diff
raction (XRD) and Raman spectroscopy, the surface of the
films was observed applying high-resolution scanning electron microscopy (SEM). For
measuring the thickness and identifying the refractive indices of the films laser
ellipsometry was used. The research was focuse
d on the sensing behavior of the sputtered
titania thin films applying quartz crystal microbalance (QCM) method, which allows
detection of mass changes in the nanogram range. Prototype QCM sensors with TiO
2
thin
films were made by our team and tested for sensitivity to NH
3
and NO
2
. These films even
in as-deposited state and without heating th
e substrates show good sensitivity. Additional
thermal treatment is not necessary, making manufacturing of QCM gas sensor simple and
cost-effective, as it is fully compatible with the technology for producing the initial
resonator. The sorption is fully reversible and the studied TiO
2
films are stable, which
makes them capable for meas
urements for long terms
Staggering behavior of the low lying excited states of even-even nuclei in a Sp(4,R) classification scheme
We implement a high order discrete derivative analysis of the low lying
collective energies of even-even nuclei with respect to the total number of
valence nucleon pairs N in the framework of F- spin multiplets appearing in a
symplectic sp(4,R) classification scheme. We find that for the nuclei of any
given F- multiplet the respective experimental energies exhibit a Delta N=2
staggering behavior and for the nuclei of two united neighboring F- multiplets
well pronounced Delta N=1 staggering patterns are observed. Those effects have
been reproduced successfully through a generalized sp(4,R) model energy
expression and explained in terms of the step-like changes in collective modes
within the F- multiplets and the alternation of the F-spin projection in the
united neighboring multiplets. On this basis we suggest that the observed Delta
N=2 and Delta N=1 staggering effects carry detailed information about the
respective systematic manifestation of both high order alpha - particle like
quartetting of nucleons and proton (neutron) pairing interaction in nuclei.PACS
number(s):21.10.Re, 21.60.FwComment: 22 pages and 6 figures changes in the figure caption
Miniaturized Gas Correlation Radiometer for the Detection of Trace Gases in the Martian Atmosphere
We present a miniaturized and simplified version of a gas correlation radiometer (GCR) capable of simultaneously mapping multiple trace gases and identifying active regions on the Mars surface. Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Reduction of the size and mass of the GCR was achieved by implementing compact, light-weight 1 mm inner diameter hollow-core optical fibers (hollow waveguides) as the gas correlation cells. In a comparison with an Earth orbiting CO2 GCR instrument, exchanging the 10 m multipass cells with hollow waveguide gas correlation cells of equivalent path length reduces the mass from approximately 150 kg to approximately 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately 1 meter in diameter by 0.05 m in height (mass and volume reductions of greater than 99%). A unique feature of this instrument is its stackable module design, with a single module for each trace gas. Each of the modules is self-contained, and fundamentally identical; differing by the bandpass filter wavelength range and gas mixtures inside the hollow-waveguide absorption cells. The current configuration contains four stacked modules for simultaneous measurements of methane (CH4), formaldehyde (H2CO), water vapor (H2O), and deuterated water vapor (HDO) but could easily be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance. Preliminary results indicate that a 1 ppb detection limit is possible for both formaldehyde and methane with one second of averaging. Using non-optimized components, we have demonstrated an instrument sensitivity equivalent to approximately 30 ppb for formaldehyde, and approximately 500 ppb for methane. We expect custom bandpass filters and 6 m long waveguides to significantly improve these promising results. Ongoing testing is being conducted on water vapor and deuterated water vapor
Evaluation of behavioral changes and subjective distress after exposure to coercive inpatient interventions
BACKGROUND: There is a lack of evidence to underpin decisions on what constitutes the most effective and least restrictive form of coercive intervention when responding to violent behavior. Therefore we compared ratings of effectiveness and subjective distress by 125 inpatients across four types of coercive interventions. METHODS: Effectiveness was assessed through ratings of patient behavior immediately after exposure to a coercive measure and 24 h later. Subjective distress was examined using the Coercion Experience Scale at debriefing. Regression analyses were performed to compare these outcome variables across the four types of coercive interventions. RESULTS: Using univariate statistics, no significant differences in effectiveness and subjective distress were found between the groups, except that patients who were involuntarily medicated experienced significant less isolation during the measure than patients who underwent combined measures. However, when controlling for the effect of demographic and clinical characteristics, significant differences on subjective distress between the groups emerged: involuntary medication was experienced as the least distressing overall and least humiliating, caused less physical adverse effects and less sense of isolation. Combined coercive interventions, regardless of the type, caused significantly more physical adverse effects and feelings of isolation than individual interventions. CONCLUSIONS: In the absence of information on individual patient preferences, involuntary medication may be more justified than seclusion and mechanical restraint as a coercive intervention. Use of multiple interventions requires significant justification given their association with significant distress
Characterization of thin MoO3 films formed by RF and DC-magnetron reactive sputtering for gas sensor applications
The present work discusses
a
technology f
or deposition and characterization of
thin
molybdenum oxide (MoO
x
,
MoO
3
)
films
studied
for gas sensor applications.
T
he samples
were
produced by
reactive radio
-
frequency (RF) and direct c
urrent (DC) magnetron sputtering.
The
composition and microstructure of the
films were studied by XPS
, XRD and Raman
spectroscopy, the
morphology
,
using
high resolution SEM. T
he research
was
focused on the
sensing
properties
of the sputtered
thin
MoO
3
films.
Highly sensitive gas sensor
s were
implemented
by depositing
films
of various thicknesses
on quartz resonators.
Making use of
the quartz crystal microbalance (QCM) method
,
the
se
sensors we
re capable
of
detect
ing
chan
ges in the molecular range.
Prototype QCM structures
with thin
MoO
3
films were tested
for sensitivity to NH
3
and NO
2
.
E
ven in as
-
deposited state and without heating
the substrates,
these films
show
ed
good sensitivity
.
Moreover
,
no
a
dditional thermal treatment is necessary,
which makes
the production
of
such
QCM gas sensor
s
simple and cost
-
effective, as it is fu
lly
compatible wit
h the technology for producing t
he initial resonator
.
Т
he films are sensitive
at
room temperature and can
reg
ister concentrations
as
low as 50 ppm
. The sorption is fully
reversible
, the
films are stable and capable
of
long
-
term
measuremen
ts
q-Analogue of
A natural embedding for the
corresponding quantum algebras is constructed through the appropriate
comultiplication on the generators of each of the and
algebras. The above embedding is proved in their -boson realization by means
of the isomorphism between the (mn)(m)(n) algebras.Comment: 11 pages, no figures. In memory of professor R. P. Rousse
Isospin symmetry breaking in an algebraic pairing Sp(4) model
An exactly solvable sp(4) algebraic approach extends beyond the traditional
isospin conserving nuclear interaction to bring forward effects of isospin
symmetry breaking and isospin mixing resulting from a two-body nuclear
interaction that includes proton-neutron (pn) and like-particle isovector
pairing correlations plus significant isoscalar pn interactions. The model
yields an estimate for the extent to which isobaric analog 0+ states in light
and medium mass nuclei may mix with one another and reveals possible, but still
extremely weak, non-analog beta-decay transitions.Comment: 8 pages, 2 figure
A deep learning-based dirt detection computer vision system for floor-cleaning robots with improved data collection
Floor-cleaning robots are becoming increasingly more sophisticated over time and with the addition of digital cameras supported by a robust vision system they become more autonomous, both in terms of their navigation skills but also in their capabilities of analyzing the surrounding environment. This document proposes a vision system based on the YOLOv5 framework for detecting dirty spots on the floor. The purpose of such a vision system is to save energy and resources, since the cleaning system of the robot will be activated only when a dirty spot is detected and the quantity of resources will vary according to the dirty area. In this context, false positives are highly undesirable. On the other hand, false negatives will lead to a poor cleaning performance of the robot. For this reason, a synthetic data generator found in the literature was improved and adapted for this work to tackle the lack of real data in this area. This synthetic data generator allows for large datasets with numerous samples of floors and dirty spots. A novel approach in selecting floor images for the training dataset is proposed. In this approach, the floor is segmented from other objects in the image such that dirty spots are only generated on the floor and do not overlap those objects. This helps the models to distinguish between dirty spots and objects in the image, which reduces the number of false positives. Furthermore, a relevant dataset of the Automation and Control Institute (ACIN) was found to be partially labelled. Consequently, this dataset was annotated from scratch, tripling the number of labelled images and correcting some poor annotations from the original labels. Finally, this document shows the process of generating synthetic data which is used for training YOLOv5 models. These models were tested on a real dataset (ACIN) and the best model attained a mean average precision (mAP) of 0.874 for detecting solid dirt. These results further prove that our proposal is able to use synthetic data for the training step and effectively detect dirt on real data. According to our knowledge, there are no previous works reporting the use of YOLOv5 models in this application.publishe
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