43 research outputs found
Isomeric pair in photonuclear reactions on Mo at end-point bremsstrahlung energy of 35-95 MeV
The Nb photonuclear reaction
was studied using the electron beam from the NSC KIPT linear accelerator
LUE-40. Experiment was performed using the activation and off-line -ray
spectrometric technique. The experimental isomeric yield ratio was
determined for the reaction products at the end-point
bremsstrahlung energy range of 35-95 MeV. The obtained
values of are in satisfactory agreement with the
results of other authors and extend the range of previously known data. The
theoretical values of the yields and the
isomeric yield ratio for the isomeric pair from the reaction were
calculated using the partial cross-sections from the TALYS1.95 code
for six different level density models . The comparison showed a noticeable
excess (more than 3.85 times) of the experimental isomeric yield ratio over all
theoretical estimates. At the investigated range of the
theoretical dependence of on energy was confirmed -
the isomeric yield ratio smoothly decreases with increasing energy.Comment: 9 pages, 9 figures, 1 tabl
Photonuclear reactions cross-sections at energies up to 100 MeV for different experimental setups
In experiments on the electron linac LUE-40 of RDC "Accelerator" NSC KIPT,
the flux-averaged cross-sections of photonuclear reactions
,
,
,
, and
were measured using the
-activation technique. The theoretical flux-average cross-sections
were computed using the
partial cross-section values from the TALYS1.9-1.95 codes and
bremsstrahlung -flux calculated using GEANT4.9.2. Two different
experimental setups were used in the experiments: an aluminum electron absorber
and a deflecting magnet to clean the bremsstrahlung -flux from
electrons. A comparison of the flux-average cross-sections measured for two
experimental setups was performed. The possibility of using the reactions
,
,
,
, and
as monitors of the bremsstrahlung
-flux for the energy range 30-100 MeV was investigated.Comment: 8 pages, 6 figures, 1 tabl
Production of Hf in photoproton reaction Ta at energy = 35-95 MeV
The production of the nuclei in the photoproton
reaction was studied at end-point bremsstrahlung
energies = 35-95 MeV. The experiment was performed at the
electron linear accelerator LUE-40 NSC KIPT with the use of the
activation and off-line -ray spectroscopy.
The experimental values of the bremsstrahlung flux-averaged cross-sections
for the
reaction were determined, and at
MeV obtained for the first time.
The measured values, also as the literature data, are significantly exceed
the theoretical flux-averaged cross-sections . The values were calculated using the cross-section
computed with the TALYS1.95 code for six different level density
models.
A comparative analysis of the calculated total cross-sections for the
reactions and
was performed. It was shown that the
photoproton to photoneutron strength ratio is
consistent with the estimates based on the isospin selection rules and the
value from the experiment.Comment: 9 pages, 4 figures, 2 table
Population immunity to SARS-CoV-2 virus in residents of the Irkutsk Region in the dynamics of the epidemic
Background. Currently, the COVID-19 pandemic in the world and in Russia remains the main event. In this regard, the study of the manifestations of the epidemic process of the new coronavirus infection COVID-19 and the patterns of its development are an urgent area of research. In the fight against this viral disease, an important role is assigned to the study of the development of population immunity to the SARSCoV-2 virus, which will make it possible to assess the dynamics of seroprevalence and the formation of post-infectious humoral immunity, forecasting the development of the epidemiological situation, elucidating the characteristics of the epidemic process, and will also contribute to planning activities for specific and non-specific prevention of the disease.The aim: to determine the dynamics of population immunity to SARS-CoV-2 among the population of the Irkutsk region during the COVID-19 pandemic.Materials and methods. As a part of the Rospotrebnadzor project of assessing population immunity to SARS-CoV-2 in the population of the Russian Federation, the research has being conducted among the population of the Irkutsk region in the periods from June 23, 2020 to July 19, 2020 (Stage 1), from September 16, 2020 to September 25, 2020 (Stage 2), from December 7, 2020 to December 18, 2020 (Stage 3) and from March 8, 2021 to March 14, 2021(Stage 4), taking into account the reacted one recommended by the WHO. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of tests for human serum or plasma for specific immunoglobulins of class G to the proteins of the SARS-CoV-2 coronavirus.The results. The research of the humoral immunity of volunteers shows that during the period of an epidemic rise in the incidence of COVID-19 in the Irkutsk region, a low level of seroprevalence was formed (Stage 1 – 5.8 ± 0.5 %, Stage 2 – 12.1 ± 0.7 %), and in conditions of a long-term maximum increase in the incidence rate – 25.9 ± 1.0 % (Stage 3) and 46.2 ± 1.2 % (Stage 4). A significant proportion (Stage 1 – 82.2 ± 3.2 %, Stage 2 – 86.1 ± 2.3 %) of asymptomatic forms of infection characterizes the high intensity of the latently developing epidemic process in the first two stages. High levels of IgG in reconvalescents of COVID-19 persisted for an average of 3 to 5 months.Conclusion. The results of assessing the population immunity to the SARS-CoV-2 virus in the population of the Irkutsk region indicate that the seroprevalence level at Stage 4 of the research was 46.2 %. After the disease, on average, 49.5 % of persons did not detect antibodies. The results obtained should be taken into account when organizing preventive measures, including vaccination, and predicting morbidity
ABOUT PAINLEVE PROPERTY OF A HYDRODYNAMIC SYSTEM
We represent conditions of hydrodynamic system when it passes the Painleve test. We use Kovaleskaya-Gambie method for fourth order ordinary differential system. We obtain Lorenz-like dynamic, hydrodynamic syste