261 research outputs found
A. A. Berzin and His Memoir
Alfred A. Berzin began to study whales in 1955 at the Pacific Research and Fisheries Center (TINRO) in Vladivostok
where he is still working at the present time. In the years before the rapid development of Soviet whaling only two fleets (Aleut and Second Kuril) were hunting whales
Variability of wing venation of the dragonfly.
Es wurde die Veränderlichkeit der Zellenanzahl in 35 Flügelabschnitten bei drei Libellenarten (Sympetrum danae Sulzer, Leucorrhinia albifrons Burmeister und Lestes sponsa Hansemann) aus der Umgebung Moskaus untersucht. Innerhalb der Population ist die Zahl der Zellen des rechten und linken Flügels praktisch gleich. In der Regel existiert ein deutlicher Geschlechtsdimophismus in der Zahl der Zellen sowohl im Vorder- als auch im Hinterflügel aller untersuchten Arten (das erfordert bei weiteren Populationsuntersuchungen an Libellen die Verwendung gleichgeschlechtlicher Individuenserien). Der Vergleich der Variabilität der ausgewählten Merkmale innerhalb einer Art zeigt die Möglichkeit, diese Merkmale zur genauen Charakterisierung nicht nur der geschlechtlichen, sondern auf der Populationsunterschiede zu verwenden. Der Libellenflügel als Organ erweist sich als günstiges Objekt zur Untersuchung von sowohl mikroevolutiven Prozessen, die innerhalb der Art ablaufen, wie auch zum Erhalt taxonomischer Charakteristika beliebiger Ebene (von Populations- bis zu Art-, Gattungs-, Familiencharakteristika).The variability of the cell number in 35 areas of the wings was studied at three species of dragonflies(Sympetrum danae Sulzer, Leucorrhinia albifrons Burmeister and Lestes sponsa Hansemann) from the vicinity of Moscow. Within the population the cell number of the right wing and the left wing is practically the same. As a rule there is a distinct sexual dimorphism in the cell number of both the fore wings and the hind wings of all the species under consideration (thus future studies of populations of dragonflies should use series of individuals of the same sex). A comparison of the variability of the chosen characteristics within a species indicates the possibility of using these characteristics to accurately define not only the sexual differences but also the differences between the populations. The dragonfly wing proves to be a suitable object for the study of microevolutionary processes in a species as well as for obtaining taxonomical data on any level (Characteristics of population, species, genus or family)
Towards a microwave single-photon counter for searching axions
The major task of detecting axions or axion-like particles has two challenges. On the one hand, the ultimate sensitivity is required, down to the energy of a single microwave photon of the yoctojoule range. On the other hand, since the detected events are supposed to be rare, the dark count rate of the detector must be extremely low. We show that this trade-off can be approached due to the peculiar switching dynamics of an underdamped Josephson junction in the phase diffusion regime. The detection of a few photons\u27 energy at 10 GHz with dark count time above 10 s and the efficiency close to unity was demonstrated. Further enhancements require a detailed investigation of the junction switching dynamics
Approaching microwave photon sensitivity with Al Josephson junctions
Here, we experimentally test the applicability of an aluminium Josephson junction of a few micrometers size as a single photon counter in the microwave frequency range. We have measured the switching from the superconducting to the resistive state through the absorption of 10 GHz photons. The dependence of the switching probability on the signal power suggests that the switching is initiated by the simultaneous absorption of three and more photons, with a dark count time above 0.01 s
3-PHENACYLURIDINE-DERIVED HYPNOTICS: ANTHOLOGY, STRUCTUREACTIVITY RELATIONSHIPS AND SYNTHESIS OF SEVERAL ACYCLONUCLEOSIDE ANALOGUES
This work was supported by the Russian Foundation for Basic Research, project # 18-33-00421
Microwave photon detection by an Al Josephson junction
An aluminium Josephson junction (JJ), with a critical current suppressed by a factor of three compared with the maximal value calculated from the gap, is experimentally investigated for application as a threshold detector for microwave photons. We present the preliminary results of measurements of the lifetime of the superconducting state and the probability of switching by a 9 GHz external signal. We found an anomalously large lifetime, not described by the Kramers\u27 theory for the escape time over a barrier under the influence of fluctuations. We explain it by the phase diffusion regime, which is evident from the temperature dependence of the switching current histograms. Therefore, phase diffusion allows for a significant improvement of the noise immunity of a device, radically decreasing the dark count rate, but it will also decrease the single-photon sensitivity of the considered threshold detector. Quantization of the switching probability tilt as a function of the signal attenuation for various bias currents through the JJ is observed, which resembles the differentiation between N and N + 1 photon absorption
Осаждение наноразмерных пленок полимера методом электронно-лучевого диспергирования политетрафторэтилена в вакууме на поверхность трековой мембраны
Исследованы структурные и электрохимические свойства композитных мембран, образующихся при осаждении на поверхность полипропиленовой трековой мембраны слоя полимера, полученного электронно-лучевым диспергированием политетрафторэтилена в вакууме
The Application of Machine Learning for Creating a Typology of Universities' Financial Models
This study presents an application of machine learning for creating a typology of Russian universities’ financial models. Large-scale national initiatives aimed at enhancing human potential and academic excellence, such as Project 5-100, university-industry consortia, world class research center programs as well as the Priority-2030 program, require relevant financial and management accounting tools enabling appropriate analyses of universities’ contribution to national scientific policy implementation. However, when conventional financial analysis and audit techniques are adopted from the corporate sector, they may prove to be irrelevant for assessing the societal impacts of universities. Existing impact study methods, such as those applied in the Russell Group universities’ impact assessment, are expensive and time consuming, so promising machine learning techniques and existing open data from government information systems were used in this study to assess universities’ financial models
Dynamic heating and ventilation of transformer substation buildings with adjustable resistance to heat transfer in windows
The article considers issues related to providing dynamic heating and ventilation of transformer substation buildings featuring designed digital voltage transformers demanding particular ambient temperatures. We have shown the efficiency of using heat reflecting screens in windows with lower transmission heat losses from the transformer substation buildings concerned
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