1,360 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
Antiphospholipid Syndrome in Acute Cerebral Blood Flow Disorders
The purpose of the present study was to dynamically analyze the role of antiphospholipid syndrome in patients with acute disturbances of cerebral blood flow. Twenty-eight patients (16 females and 12 males) aged between 47 and 61 years were examined. The following criteria for patient's incorporation into the study were observed: presence of a focal neurological deficit, ultrasonographic evidence of disturbed cerebral blood flow, CT or MRI data about brain stroke. According to the data from the clinical or x-ray examination, the patients were divided into three groups: with hemorrhagic, embolic, or thrombotic stroke. Anticardiolipid (aCL) antibodies were assessed by ELISA method for a 12-month period. Elevated titres of aCL antibodies were proved in 12 patients (in 43 per cent of the cases) - in ten with ischemic and in two - with hemorrhagic stroke. The treatment with neuroprotective, antiaggregation and immunomodulatory means resulted in improvement of the clinical symptoms and antiphospholipid syndrome as well. It could be concluded that the summarized clinical, roentgenological and immunological data suggest the involvement of elevated titres of aCL antibodies into the pathogenesis of the acute cerebral blood flow disorders. The estimation of these antibodies should be considered obligatory in the patients with stroke with a view to enlargement of the prognostic criteria and more adequate therapeutic approach
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
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
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
Immobilization of Trichosporon cutaneum R 57 Cells onto Methylcellulose/SiO2 Hybrids and Biosorption of Cadmium and Copper Ions
Methylcellulose/Silica (MC/SiO2) hybrids were synthesized via poly step sol-gel method. SiO2 was included into the hybrids from two silica precursors - methyltriethoxysilane (MTES) and ethyltrimethoxysilane (ETMS) with different quantity of organic part-5, 20 and 50 wt.%. The filamentous yeasts Trichosporon cutaneum strain R 57 was immobilized onto the synthesized MC/SiO2 hybrids. After immobilization the hybrid materials were used in the processes of sorption of cadmium and copper ions. The obtained results of protein content analysis indicated that the amount of protein increased with increasing of MC in the hybrids. It was established that the maximal efficiency of copper and cadmium removal were observed for hybrid materials containing MTES and 50 wt.% MC - 66% and 26% respectively. For ETMS and 50 wt.% MC a high value of copper removal was 56% and for cadmium - 45% removal, respectively. FTIR analysis of free and immobilized cells with metal ions was conducted. SEM images showed successful immobilization of the yeasts cells. Second order model was employed in order to investigate the kinetics of copper and cadmium biosorption
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