Издательство: Просвещение
Год выпуска: 1981
Количество страниц: 196 с.
Издательство: Якутский научный центр СО РАН
Год выпуска: 1992
Количество страниц: 252 с.
Издательство: Наука, Сибирское отделение
Год выпуска: 1986
Количество страниц: 274 с.
Количество страниц: 11 с.
Currently, the use of electron microscopes in medicine is developing intensively, including scanning electron microscopes (SEM), which are designed to solve a huge number of problems in various fields with a wide range of electron accelerating voltages and electron beam energies. The development of an SEM with certain emission characteristics, with a range of lower beam energies for the study of biological samples, is an urgent task because modifying the SEM to solve problems in medicine, for example, would make it possible to obtain higher-quality images of biospecimens for diagnostics and monitoring the effectiveness of therapy. To develop new SEMs with certain characteristics, it is proposed to conduct less expensive research using numerical methods based on mathematical models of processes in electron-optical SEM systems. In this regard, this work sets the task of determining the size and shape of the beam, the main emission characteristics of the field electron cathode (FEC) of the SEM, which is under the influence of the electric field that excites electron emission and the external longitudinal magnetic field by studying the movement of the outermost electron of the beam, taking into account the influence of space charge beam electrons, external magnetic field. In the model, the FEC is approximated by a paraboloid of rotation, and the concept of a boundary “outermost” electron is introduced, the trajectory of which determines the shape and size of the beam. The problem of calculating the emission characteristics along the trajectory of the outermost electron of a FEC is solved using a mathematical model that includes the following equations: motion of the "outermost" electron, Maxwell outside and inside the beam, continuity of the current density, Fowler-Nordheim equation. As a result, a system of 18 first-order ordinary differential equations was obtained, the numerical calculation of which using the 4th order Runge-Kutta method allows us to obtain the emission characteristics of the FEC. As a result, it is suggested that it would be feasible to modify SEMs for more effective use in the medical field, taking into account their increasing use in disease diagnosis and the possible improvement of image quality through the development of FEC SEMs with more suitable characteristics.
Математическое моделирование эмиссионных характеристик полевого электронного катода в растровом электронном микроскопе в условиях исследования биообразцов / С. Н. Мамаева, Н. В. Егоров, Б. В. Яковлев [и др.] ; Северо-Восточный федеральный университет им. М. К. Аммосова, Санкт-Петербургский государственный университет, Московский государственный университет имени М. В. Ломоносова // Вестник Северо-Восточного федерального университета им. М. К. Аммосова. - 2024. - Т. 21, N 1 (95). - С. 70-80. - DOI: 10.25587/2222-5404-2024-21-1-70-80
DOI: 10.25587/2222-5404-2024-21-1-70-80
Количество страниц: 7 с.
- Математика. Естественные науки > Общая биология. Антропология. Вирусология. Микробиология,
- Прикладные науки. Медицина. Ветеринария. Техника. Сельское хозяйство > Сельское хозяйство. Лесное хозяйство. Охота. Рыболовное хозяйство,
- НАУКА ЯКУТИИ > МАТЕМАТИКА. ЕСТЕСТВЕННЫЕ НАУКИ > Общая биология. Антропология. Вирусология. Микробиология,
- НАУКА ЯКУТИИ > ПРИКЛАДНЫЕ НАУКИ. МЕДИЦИНА. ТЕХНИКА. СЕЛЬСКОЕ ХОЗЯЙСТВО > Сельское хозяйство. Лесное хозяйство. Охота. Рыболовное хозяйство.
The importance of studying the microelement composition of soils and vegetation in the Northern territories is due to the role of microelements in soil formation under cryolithozone conditions, and secondly, the influence of the microelement background of plants on the physiological functions of animals and humans. At the same time, heavy metals deserve special attention as they pose a threat to all living organisms due to their ability to accumulate. The article presents data on the content of heavy metals in the aboveground parts of meadow grasses growing under cryolithozone conditions - in the Khangalassky district, located in the Central Yakut biogeochemical province. Atomic absorption spectral analysis showed that the content of heavy metals - cadmium and lead - in the aboveground parts of the studied plants varied significantly depending on the place of collection, but did not exceed the maximum permissible concentrations. The concentration of zinc in some of the herbal collection points exceeded the maximum permissible concentrations. The need to study the content of heavy metals in plants is due to the fact that they are the primary link in the movement of toxic elements along the trophic chain into the human body. Lead and cadmium accumulate in parenchymal organs, are carcinogenic and affect the morbidity and mortality of the northern population.
Миронова, Г. Е. К вопросу о содержании токсических элементов в луговых травах сельской местности Хангаласского района / Г. Е. Миронова, А. А. Григорьева ; Северо-Восточный федеральный университет им. М. К. Аммосова, Якутский научный центр комплексных медицинских проблем, Арктический медицинский центр // Вестник Северо-Восточного федерального университета им. М. К. Аммосова. - 2024. - Т. 21, N 1 (95). - С. 5-11. - DOI: 10.25587/2222-5404-2024-21-1-5-11
DOI: 10.25587/2222-5404-2024-21-1-5-11
Количество страниц: 12 с.
Pyrola incarnata is a typical boreal species that is widespread in the taiga zone. In Central Yakutia, it often acts as a co-dominant in the herbaceous-shrub layer of larch forests. Based on the results of analysis of geobotanical descriptions according to the Brown-Blanke method, all phytocenoses with the participation of P. incarnata were divided into 4 associations (acc. Saxifrago bronchialis-Pinetum sylvestris, acc. Limnado stelleri-Laricetum cajanderi, acc. Aquilegio parviflorae-Laricetum cajanderi and acc. Ledo palustris-Laricetum cajanderi), which belong to the class of coniferous forests Vaccinio-Piceetea Br.-Bl., Siss. et Vlieger 1939 [1]. The article presents data on the analysis of environmental parameters and floristic analysis of forest communities with the participation of Pyrola incarnata. The leading families and related species involved in the formation of phytocenoses together with P. incarnata, the dependence of the state of P. incarnata on the floral composition of phytocenoses were identified. The identification of the ecological preferences of P. incarnata was carried out according to the method of environmental humidity indicators and richness factors-salinity. As a result of the studies conducted in the conditions of Central Yakutia, we have found out that the species is characterised by a relatively wide range of tolerance in terms of the moisture factor. It prefers growth sites from dry meadows to raw meadows type of moisture, stages from 59.2 to 68.3, and in terms of the richness-salinity prefers rather rich soils, stages from 8.2 to 11.5. At the same time, the phytocenoses of assoc. Ledo palustris-Laricetum cajanderi, Limnado stelleri-Laricetum cajanderi and Saxifrago bronchialis-Pinetum sylvestris were clearly distributed along the gradients of richness-salinity and moisture, and the communities of assoc.. Aquilegio parviflorae-Laricetum cajanderi tends towards dry meadow conditions and is located completely on top of the indicators of the communities of the association Saxifrago bronchialis-Pinetum sylvestris, and partially overlapping the area. The indicators of the Limnado stelleri-Laricetum cajanderi assoc. did not affect the area of wetter conditions, the zone of distribution of the phytocenoses of the Ledo palustris - Laricetum cajanderi assoc.
Никифорова, А. А. Эколого-флористическая характеристика лесных сообществ с участием Pyrola incarnatа (DC.) Freynв условиях Центральной Якутии / А. А. Никифорова ; Северо-Восточный федеральный университет им. М. К. Аммосова // Вестник Северо-Восточного федерального университета им. М. К. Аммосова. - 2024. - Т. 21, N 1 (95). - С. 12-23. - DOI: 10.25587/2222-5404-2024-21-1-12-23
DOI: 10.25587/2222-5404-2024-21-1-12-23
Количество страниц: 13 с.
The interplanetary magnetic field (IMF), frozen into the solar wind plasma, determines the level of geomagnetic activity and significantly affects the large-scale structure of the high-latitude ionosphere. Variations in the IMF components lead to non-stationarity of the magnetospheric convection electric field, causing changes in the spatio-temporal distribution of charged particles in the ionosphere. The situation is complicated by the fact that the geographic and geomagnetic poles do not coincide, which leads to universal time control (UT control) of the parameters of the high-latitude ionosphere. The effect of the poles displacement is most manifest in winter. Therefore, in this work, within the framework of a nonstationary mathematical model of the F-region of the ionosphere in Euler variables, taking into account the displacement between the geographic and geomagnetic poles, we study the influence of the interplanetary magnetic field components on the large-scale structure of the high-latitude ionosphere in winter. For this, the Weimer model of high-latitude electric potentials, which depends on the IMF, was used. As a result, of numerical modelling, it is shown that the IMF components affect the shape, size and spatio-temporal location of the main structural features of the high-latitude ionosphere depending on universal time. The obtained effect of ionisation tongue separation requires experimental confirmation. The obtained results demonstrate that the developed non-stationary three-dimensional model of the ionosphere in Euler variables can be applied to the study of ionospheric disturbances, including ionospheric disturbances associated with changes in the IMF components.
Гололобов, А. Ю. Численное моделирование влияния ММП на крупномасштабную структуру ионосферы с учетом несовпадения полюсов / А. Ю. Гололобов, И. А. Голиков ; Институт космофизических исследований иаэрономии им. Ю. Г. Шафера // Вестник Северо-Восточного федерального университета им. М. К. Аммосова. - 2024. - Т. 21, N 1 (95). - С. 45-57. - DOI: 10.25587/2222-5404-2024-21-1-45-57
DOI: 10.25587/2222-5404-2024-21-1-45-57
Количество страниц: 12 с.
This work reports on the methods developed by our group at ShICRA SB RAS to forecast negative manifestations of space weather from ground-based measurements of cosmic rays. Such manifestations are registered on the Earth in the form of decreases in galactic cosmic rays known as the Forbush effects, various types of geomagnetic and ionospheric disturbances, as well as auroras. Only the latters are directly visible to the naked eye, while the rest can only be detected with the help of various instruments. These occurrences are all caused by passage through the Earth’s orbit, such as the substantial influxes of charged particles from both solar and interplanetary sources, interplanetary shock waves, ejections of solar material and high-speed solar wind streams, all of which are attributed to the level of solar flares and coronal activity. The state of near-Earth space weather is determined by their presence. To monitor this state, we use data collected from ground-based cosmic ray stations and employ multiple methods to analyse these measurements. Additionally, we incorporate data from the Dst-index of the geomagnetic field and measurements of the interplanetary environmental parameters gathered by ACE, WIND, SOHO and DSCOVR spacecraft at the L1 libration point to confirm events. This has led to the development of techniques for predicting terrestrial effects of space weather in the short-term (1-3 days). Our findings suggest that it is feasible to predict the occurrence of severe geomagnetic storms in real-time through the utilisation of solely ground-based measurements from cosmic ray stations.
Прогноз возмущений солнечного ветра и геомагнитных бурь на основе наземных измерений космических лучей / А. С. Зверев, П. Ю. Гололобов, В. Г. Григорьев [и др.] ; Институт космофизических исследований и аэрономии им. Ю. Г. Шафера // Вестник Северо-Восточного федерального университета им. М. К. Аммосова. - 2024. - Т. 21, N 1 (95). - С. 58-69. - DOI: 10.25587/2222-5404-2024-21-1-58-69
DOI: 10.25587/2222-5404-2024-21-1-58-69
Количество страниц: 8 с.
The paper presents the results of a study on the search for correct methods for measuring a high-value current pulse, which will be used to conduct research on the electroplastic effect. The electroplastic effect is the effect of electric current pulses on the plastic flow of metals. Electroplastic metal forming technology is a relatively new metal forming process that is energy efficient, environmentally friendly and versatile. In particular, it can be used to process metals or alloys that are difficult to process using conventional manufacturing processes. For the experimental study of the electroplastic effect, it became necessary to measure pulse currents of large magnitude, not only in amplitude, but also in the shape of the pulse. The pulsed current causes the formation of an alternating electromagnetic field near the conductors, so it can be measured with a Rogovsky current transformer. The results of the work present a schematic electrical diagram and a photograph with the appearance of an experimental installation for the study of the electroplastic effect. The results of measurements of the current value, the voltage drop on the sample and the dependence of the peak voltage values on the sample on the peak current value are shown. After making calculations and renormalising the data for the voltage drop on the sample according to the peak value of the current obtained on the transformer, the authors obtained the desired current values. The error of this method is estimated by calculating the total capacitance of capacitors, which does not exceed 2%.
Разработка способа измерения импульсных токов большой величины / В. П. Татаринов, П. С. Татаринов, Ю. В. Бебихов [и др.] ; Северо-Восточный федеральный университет им. М. К. Аммосова, Политехнический институт (филиал), Институт физики молекул и кристаллов УФИЦ, Институт проблем сверхпластичности металлов // Вестник Северо-Восточного федерального университета им. М. К. Аммосова. - 2024. - Т. 21, N 1 (95). - С. 81-88. - DOI: 10.25587/2222-5404-2024-21-1-81-88
DOI: 10.25587/2222-5404-2024-21-1-81-88
Количество страниц: 6 с.
Time to the most recent common ancestor (TMRCA) of Sakha men with haplogroup N3a2-M1982 of the Y chromosome was evaluated by 23 STR markers using the mutation rate constant of Y-STR loci that we had previously calculated. The obtained TMRCA values indicate a period of ~1300-1400 years ago (VI-VII centuries AD), associated with the primary expansion of the population. Based on genetic data and analysis of texts from ancient Chinese chronicles, a hypothesis has been put forward about the connection of the ancestral Sakha population with the Yuzhe people, who supplied mammoth ivory to China.
Адамов, Д. С. Датировка времени ближайшего общего предка саха (якутов) с гаплогруппой N3A2-M1982 Y-хромосомы: новые этногенетические реконструкции / Д. С. Адамов, А. Н. Алексеев, С. А. Федорова ; Якутский научный центр комплексных медицинских проблем, Северо-Восточного федерального университета им. М. К. Аммосова, Институт естественных наук, Институт гуманитарных исследований и проблем малочисленных народов Севера // Якутский медицинский журнал. - 2024. - N 2 (86). - С. 88-93. - DOI: 10.25789/YMJ.2024.86.21
DOI: 10.25789/YMJ.2024.86.21