bluuebunny/crossref_metadata_2025 huggingface dataset:
Fast Fourier transform-volume integral: a smart approach for the electromagnetic design of complex systems in large fusion devices
Authors: Bettini P , Torchio R , Lucchini F , Voltolina D , Alotto P
Published: November 2020

A volume integral (VI) equation method based on the fast Fourier transform (FFT) is proposed for the electromagnetic simulation of complex systems in large magnetic confinement fusion (MCF) devices. Such FFT-VI allows for dramatically reducing the time and the human effort required to adapt the CAD input files to models suited for electromagnetic simulations. Moreover, with FFT-VI the mesh generation is performed automatically and is very efficient and robust. The adoption of the FFT allows for significantly reducing the computation time and the memory requirements, therefore making simulations with several millions of unknowns feasible. Numerical results show that, in terms of numerical performances, the FFT-VI method applied to challenging electromagnetic problems in representative MCF devices is markedly superior with respect to the state of the art VI techniques. A sample implementation of FFT-VI is made publicly available.
Parasitic subthreshold drain current and low frequency noise in GaN/AlGaN metal-oxide-semiconductor high-electron-mobility field-effect-transistors
Authors: Takakura K , Putcha V , Simoen E , Alian A R , Peralagu U , Waldron N , Parvais B , Collaert N
Published: November 2020

The impact of the short gate length on the drain current and low frequency (LF) noise in GaN/AlGaN metal-oxide-semiconductor high-electron-mobility field-effect-transistors has been studied. In some short devices, a parasitic subthreshold current is observed. In this article, the origin of parasitic subthreshold currents were explored using LF noise and trapping transient measurements. The LF noise power spectral density (PSD) of the devices without parasitic drain current decreased monotonically with the decrease of the drain current, while the PSD of the device with the parasitic drain current strongly increased for lower drain current. The 1/f
1.5 noise corresponding with the parasitic leakage can be explained by the level broadening of generation-recombination centers in the GaN channel. This is confirmed by the trapping transient measurements, revealing a temperature-independent time constant, associated with the leakage path in short channel transistors, exhibiting the subthreshold humps.
Random deposition with surface relaxation model in u
v flower networks
Authors: Kim Jin Min
Published: November 2020

Random deposition with a relaxation model in (u, v) flower networks is studied. In a (2, 2) flower network, the surface width W(t, N) was found to grow as b ln t in the early period and follows a ln N in the saturated regime, where t and N are the evolution time and the number of nodes in the network, respectively. The dynamic exponent z, obtained by the relation z = a/b, was z ≈ 2.11(10), which is consistent with the random walk exponent d
w = 2 in the network. For u + v ⩾ 5(u ⩾ 2, v ⩾ u), i.e. the (2, 3) and (3, 3) flower networks, the surface width grows following power-law behavior with some corrections, where the growth exponent β and roughness exponent α are controlled by spectral dimension d
s and fractal dimension d
f of the substrate network.
Parallel temperature interfaces in the Katz–Lebowitz–Spohn driven lattice gas
Authors: Mukhamadiarov Ruslan I , Täuber Uwe C
Published: November 2020

We explore a variant of the Katz–Lebowitz–Spohn (KLS) driven lattice gas in two dimensions, where the lattice is split into two regions that are coupled to heat baths with distinct temperatures. The geometry was arranged such that the temperature boundaries are oriented parallel to the external particle drive and resulting net current. We have explored the changes in the dynamical behavior that are induced by our choice of the hopping rates across the temperature boundaries. If these hopping rates at the interfaces satisfy particle-hole symmetry, the current difference across them generates a vector flow diagram akin to a vortex sheet. We have studied the finite-size scaling of the particle density fluctuations in both temperature regions, and observed that it is controlled by the respective temperature values. Specifically, if the colder subsystem is maintained at the KLS critical temperature, while the hotter subsystem’s temperature is set much higher, the interface current greatly suppresses particle exchange between the two regions. As a result of the ensuing effective subsystem decoupling, strong fluctuations persist in the critical region, whence the particle density fluctuations scale with the KLS critical exponents. However, if both temperatures are set well above the critical temperature, the particle density fluctuations scale according to the totally asymmetric exclusion process. In addition, we have measured the entropy production rate in both subsystems; it displays intriguing algebraic decay in the critical region, while it saturates quickly at a small but non-zero level in the hotter region. We have also considered another possible choice of the hopping rates across the temperature interfaces that explicitly breaks particle-hole symmetry. In that case the boundary rates induce a net particle flux across the interfaces that displays power-law behavior, until ultimately the particle exclusion constraints generate a clogging transition to an inert state.
Thermohydraulic simulation of a channel with targets for production of radioactive isotopes in the IVV-2M nuclear reactor
Authors: Litvinov D N , Kostarev V S , Klimova V A , Tashlykov O L , Aristov N M
Published: November 2020

The importance of radioisotope products usage in industry, science and medicine is underlined. The necessity of safety ensuring and radiation protection optimization while transporting the containers with radioactive isotopes is postulated. The information on isotope products making in the IVV-2M nuclear reactor of Research Institute of Nuclear Materials, JSC, from the beginning of 1990-ies is given. The data on application properties of Selenium 75 isotope are presented. The requirements to the thermohydraulic conditions of Se 75 isotope production in the nuclear reactor are formulated. The stages of a solid model development of a target for Se-75 isotope production as a part of an irradiation device of IVV-2M nuclear reactor are described. The results of hydraulic simulation of the coolant flow for various ways of devices arranging in the irradiation channel of the reactor are given. The analysis of thermohydraulic processes was performed with the help of SolidWorks Flow Simulation software.
To estimate reliability of hydroaccumulator system of nuclear power plants and improve its design and reliability
Authors: Rana Abdul Awal , Samokhin DS , Shahabuddin A K M , Haque Zihad Ul , Sanam Sadbi Ahmad
Published: November 2020

There are around twenty branches in a Nuclear Power Plant that operate to maintain the plant and one of the most important branches of them is ‘Safety and Reliability’. Approximately forty percent of the investment is paid to ensure the safety and reliability of the plant. Goal of this research work is to estimate reliability of a mechanical system which is chosen as Hydroaccumulator System of VVER type reactor. Getting the reliability, we will be trying to improve the system and enhance its reliability. To do so, firstly, reliability is calculated from a ‘prototype reactor’s’ hot loop which is located at Obninsk Institute for Nuclear Power Engineering (INPE). Thus, calculations were done and its applications being known, then finally these formulas and experiences are being used to calculate and improve the Hydroaccumulator System’s design along with its reliability to increase the safety of the NPP.
Analysis of the vibrational monitoring data regarding VVER type reactor installation
Authors: Sanam Sadbi Ahmad , Nakhabov Alexander , Haque Zihad Ul
Published: November 2020

Vibrational data monitoring system is designed to observe, detect and study any vibration caused in the NPP working cycle by different factors. The objective of the work is to analyze vibrational monitoring data of the primary circuit installation of VVER reactor to acquire knowledge of the characteristics of equipment vibration. Data has been collected using displacement sensors and pressure fluctuation sensors attached to the equipment. Data processing is carried out in R software. The work gives an overall idea of the vibrational data processing, visualization and how to present it by different graphics which will help the NPP operator for taking necessary steps.
The effect of varying collimator geometry in alpha spectrometry of environmental analysis
Authors: Amoah P A , Pripachkin D A
Published: November 2020

Assessment of radioactive aerosols in the atmosphere has always been an important field of study due to its effects on many biological systems. The efficiency in measuring these aerosols is therefore critical to research and industrial practice, thus; the principles and methods of geometry development to improve efficiency and resolution is paramount. The aim of this study is to use numerical simulation with MATLAB to improve the resolution and detection efficiency of an alpha spectrometer with varying collimator geometries. A collimator between a radiation source and a detector plays a very important role in identifying specific radionuclides among various species in a radioactive environment. The geometric model of the collimator being considered here is that of a triangular and a hexagonal shape. To evaluate the counts, randomly obtained data using Microsoft excel was used, considering the specified boundary conditions in a two-dimensional plane. Various counts ranging from 100 to 100,000 were analyzed to obtain the results of a log efficiency curve using MATLAB. Subsequent counting efficiency curves were then determined relative to the dimensions. An average value of 0.44 ± 0.1106 was determined for the efficiency. With emphases on the apothem of the geometries being studied, the triangular shaped collimator has theoretically shown to produce a higher resolution though with a possible decrease in detection efficiency.
Natural radioactivity around Rooppur nuclear power plant before commissioning
Authors: Sadhukhan Ramit Kumar , Synzynys B I
Published: November 2020

A detailed overview of the natural and anthropogenic activity concentrations in soil, surface and groundwater, agricultural products, food, river sediments, aquatic flora and fauna, air and radon hazards in the vicinity of the first ever under-construction Rooppur nuclear power plant (NPP) in the People’s Republic of Bangladesh has been portrayed in the current exhaustive review article. Most of the reported data have been obtained using gamma-ray spectrometry. A comparative study for the activity concentrations around Rooppur NPP site with other studies performed in different areas in Bangladesh has also been presented. All the reported values of activity concentrations are comparable to global averages and are within permissible limits, hence authenticating the radiological safety of the region. The content of 90Sr and 137Cs in water samples is relatively low averaging to 0.06 and 0.07 Bq l−1 respectively. Furthermore, activity of 137Cs in soil samples is below detection level, proving the absence of activity due to fallout in this region. The study provides a baseline of radioactivity in the proposed Rooppur NPP site hence allowing the observation of changes and the identification of impacts caused by the technogenic changes of background radiation after commissioning of the NPP on the environmental situation in the region.
Experimental model for study bacteriophage bioaccumulation by a bivalve Unio pictorium (L.1758)
Authors: Karmanova A N , Zimin A A
Published: November 2020

The filter-feeding bivalves capture particles of small living organisms, including bacteria and single-cell eukaryotes, from their water environment. In the previous studies bioaccumulation of viruses by bivalve molluscs had been shown. Being cultivated in the environment polluted with waste waters, these filter-feeding aquatic organisms can accumulate microorganisms, including human pathogenic bacteria and viruses, and become a health risk factor causing outbreaks of various diseases, mainly the intestine infections. Bacteriophages may serve as a safe model for investigation of virus capture from environmental waters by mollusks; besides the investigations of phage bioaccumulation give insight into the natural mechanisms of the process. We developed a simplest experimental unit, microcosm, observing bacteriophages bioaccumulation by a freshwater bivalve Unio pictorium. The bioaccumulation process was tested with two T4 bacteriophage concentrations. The phage titer in the mollusk water environment first decreased due to its bioaccumulation and then essentially increased after the long incubation of the system. The results allowed us to suppose that the bacteriophage propagates in the E.coli population inhabiting the intestine tract of a mollusk taken from natural environment.
Feasibility of nitric oxide synthesis inhibitor for the treatment of combined radiation injuries
Authors: Filimonova M V , Shitova A A , Soldatova O V , Shevchenko L I , Uzhakov V V , Yakovleva N D , Kosachenko A O , Filimonov A S
Published: November 2020

The model of combined radiation-thermal injury (CRTI) in mice was experimentally and histologically verified: exposure to60Co-radiation at a dose of 7 Gy (0.39 Gy/min) on the Agat device and the subsequent thermal effect on the GL6 device on the back, leading to the development of a 3B degree burn on 10% of the body surface. This model was used to confirm the positive influence of the NOS inhibitor T1023 on the course of CRTI. It was found that a single i.p. administration of T1023 72 h after CRTI application caused a nearly statistically significant (p = 0.051) increase in the 30-day survival rate of animals. The data obtained indicate the need for further detailed study of NOS inhibitor effects on the course of acute radiation syndrome (ARS) and CRTI.
Estimation of antitumor activity of compound T1097 - NOS inhibitor and glycolysis inhibitor - on experimental Erlich carcinoma in vivo
Authors: Shitova A A , Soldatova O V , Filimonova M V , Shevchenko L I , Saburova A S , Podosinnikova T S , Filimonov A S
Published: November 2020

The antitumor potential of a new original compound T1097 to realize a complex antineoblastic effect - NOS-inhibiting anti-angiogenic and HK2-inhibiting hypoxia-oriented cytotoxic - was investigated on the model of transplantable Ehrlich carcinoma in vivo. During the entire observation period, T1097 showed pronounced dose-dependent antitumor properties: statistically significant inhibitory effect of T1097 on the growth of tumor nodes exceeded the effect of original compound - HK2-inhibitor 3-bromopyruvate in an equimolar dose. The maximum antineoblastic effect (61%) of T1097 was obtained with its subchronic parenteral administration at a dose of 17 mg/kg and was not accompanied by the development of tumor resistance. Our findings confirm the prospects of this direction in the search for new drugs.
Environmental impact of the Research Institute of Physical Chemistry in Obninsk on soils of the nearby territory
Authors: Fernandez S Q , Oudalova A A , Melinkova T V , Kiseleva L A , Montaño R , Ziouche M
Published: November 2020

This work focuses on the study of radioactive and chemical contamination of the soil caused by non-power generation nuclear facilities. For this purpose, the environmental monitoring of terrestrial ecosystems around the Karpov Institute of Physical Chemistry, located in the Obninsk region and exploiting research nuclear reactor, has been carried out. The annually published environmental safety reports of the Karpov Institute for the period of 2011-2018 served as sources of the initial information about the facility impact on the environment. In summer 2019, the sampling of soils around the facility was carried out in 19 locations. In laboratory studies, the following indexes of physical and chemical properties of the soil are studied: type of the soil, soil density, hygroscopic moisture, moisture capacity, acidity. Instrumental methods such as potentiometric analysis were performed to determine the content of chloride in the soil. Specific activities of radionuclides were measured in soils using gamma spectrometry. It was found that the physical and chemical properties vary from point to point. Specific activities of radionuclides in the soil also vary, and in some points the radionuclides content is particularly higher than in others. Finally, all the data were compared with a similar research done in the previous year, and we found that our physical and chemical properties are similar and the specific activities are little lower than the previous year. For everything mentioned before, it is strongly suggested that more studies about the consequences to the environment and humans should be done, in more nuclear non-power facilities.
Oceanic evolution of the enzyme repairing the UV-induced DNA lesions
Authors: Karmanova A N , Zimin A A
Published: November 2020

Solar ultraviolet has a greater impact on marine ecosystem. Bacteria and viruses on ocean surface waters are most exposed to UV radiation on the Earth. In this work, the distribution of the denV gene in samples of marine microbiota was investigated by metagenomic and bioinformatic methods. The bifunctional enzyme encoded by this gene performs excision repair of pyrimidine dimers, the main photoproduct of UVB radiation. 23 homologues of the amino acid sequence of Escherichia virus T4 endonuclease V were found in the Global Ocean Sampling (GOS) database, a metagenome of the microbiota of ocean surface water. Phylogenetic study of these sequences showed that most of them are similar to homologues from cyanobacteria. 3 GOS homologues were found to be more similar to the protein of the marine bacteria Alteromonas sp. Based on the performed phylogenetic analysis it was suggested a horizontal transfer of the denV gene between the Tequatrovirus phages, Enterobacteria, and Bacillus sp. Further research in this direction may shed light on the origin of the DenV protein and its ecological role in marine bacteria and viruses communities.
Damage to the digestive tract of monogastric animals by “hot” radioactive particles
Authors: Shapovalov S , Kozmin G , Budarkov V , Zenkin A , Denisova E , Kurachenko Yu , Fesenko S
Published: November 2020

For the first time, the dosimetric characteristics of the gastrointestinal tract damaged of the monogastric animals (rats, guinea pigs, pigs) due to peroral ß-irradiation that cause ulcerative lesions of the gastrointestinal tract are presented. The main factors in the formation of such ulcerative lesions are the uneven distribution of particles in the contents of the digestive tract (DT), the concentration of particles in certain areas of the mucous membrane, followed by the formation of local radiation levels that exceed the average values of absorbed doses by more than 3 times. Clinical manifestations of irradiation with a pathoanatomic assessment of the process of ulcer formation made it possible to classify the disease as radiation ulcerative gastroenterocolitis and distinguish extremely severe, severe, medium and mild degrees depending on the amount of incoming activity of “hot” radioactive particles and absorbed doses of ionizing radiation formed in the DT.
Climate change in the Arctic: causes and mechanisms
Authors: Alekseev G V , Glok N I , Vyazilova A E , Kharlanenkova N E
Published: November 2020

Atmospheric heat and moisture transfers from the North Atlantic make the main contribution to the Arctic warming in winter. The increase in transfer is associated with changes in atmospheric circulation in the Northern Hemisphere under the influence of the sea surface temperature (SST) in low latitudes, where the bulk of the heat influx from the Sun accumulated. The mechanism of influence includes the interaction between the circulation of the ocean and atmosphere, which enhances the oceanic heat influx into the Norwegian and Barents seas, and atmospheric transport to the Arctic. SST rises with participation of orbital-forced increase of the solar insolation. Changes in insolation are small, but their effect is enhanced by feedbacks between temperature, water vapour content and downward long-wave radiation in low latitudes. An increase in water inflow, heat and moisture transfers to the Atlantic Arctic lead to increase in air temperature, water vapour content, downward long-wave radiation, and a reduction of ice thickness growth and its extent in the Barents and Greenland Seas in winter.
CMIP6 simulations of GPP growth satisfy the constraint imposed by increasing CO2 seasonal-cycle amplitude
Authors: Alexandrov G A
Published: November 2020

The positive effect of rising atmospheric carbon dioxide concentration ([CO2]) on gross primary production (GPP) is one of the factors that determine the strength of the carbon sink provided by terrestrial ecosystems. CMIP5 models tended to underestimate this effect. The study of CMIP6 simulations of GPP shows that GPP sensitivity to [CO2] assumed by increasing CO2 seasonal-cycle amplitude falls within the range of the values assumed by model runs. This make it possible to find the weights that force the weighted mean of GPP simulations to satisfy the constraint imposed by increasing CO2 seasonal-cycle amplitude.
The effect of Arctic warming on Moscow climate continentality
Authors: Alexandrov G A , Bokuchava D D , Ginzburg A S , Golitsyn G S , Semenov V A
Published: November 2020

The annual cycle of incoming solar radiation is the major factor that determines the amplitude of the annual cycle of the surface air temperature over the continents in the Northern Hemisphere. There are, however, other important factors that contribute to the seasonal temperature difference. The combined effect of these factors is characterized by the Gorczinski’s continentality index (GCI). The gradual decrease of Moscow GCI during the second half of the 20th century could be attributed to the combined effect of the warming due to increasing atmospheric concentration of carbon dioxide and intensification of the zonal atmospheric circulation. However, these factors cannot explain the increase of Moscow GCI during the 1920-1950 period. Taking into account the Arctic temperature variations with pronounced multi-decadal variability helped us to fill this gap in the explanation of the historical changes in Moscow climate continentality.
Influence of global warming and climate continentality on the Moscow urban heat island
Authors: Ginzburg A S , Alexandrov G A
Published: November 2020

The intensity of an urban heat island depends on the location, layout and development of the city, the number and density of its population, and the energy consumption of the urban economy. These dependencies can vary greatly from city to city. In recent years, more and more attention has been paid to the dependence of the city’s climate characteristics on global and regional climate processes, their trends and variations. At present, there is no clear answer to the question of how climate changes affect the evolution of an urban specific city, since modern climate changes in different cases can both increase and decrease the intensity of the urban heat island. This work discusses the reasons some stabilization of the intensity of the Moscow heat island, observed in the second half of the XX century and early XXI century, and the relationship of this phenomenon with the weakening of continentality climate in the Moscow region.
Estimation of C-CO2balance of natural steppe ecosystems: Khakassia and Tuva (Eastern Siberia, Russia) case studies
Authors: Golubyatnikov L L , Kurganova I N , Lopes de Gerenyu V O
Published: November 2020

The study of carbon balance of terrestrial ecosystems is considerable important for the forecasts of climate and environmental changes. Using a geoinformation-analytical method and a climate-driven regression model, we have calculated the C-CO2balance of natural steppe ecosystems of Khakassia and Tuva. Our research has shown that natural steppes of the region under study are a significant sink of carbon dioxide from the atmosphere. The intensity of this carbon flux in the region can be estimate as 184±41 gCm−2yr−1. The annual absorption of carbon dioxide in the natural steppe ecosystems of Tuva and Khakassia is evaluated as 6.9±2.2 Mt C-CO2.
An Investigation of circulation regime variability and dangerous weather phenomena in Russia in the 21stcentury
Authors: Kononova N K , Lupo A R
Published: November 2020

The variability of Northern Hemisphere circulation types from 1899-2018 are analyzed and the classification of atmospheric circulation types in the early 21st century are shown. These are associated with the frequency of dangerous weather phenomena, natural processes, and disasters within Russia during this time. Against this background, the synoptic conditions for the formation of extreme precipitation and floods, as well as natural fires in 2019 are considered. It is shown that an increase in the frequency of occurrence of stationary anticyclones and blocking flow regimes as well as an extension of the Mediterranean storm track was associated with an increase in the frequency of extreme precipitation and dangerous natural processes. Additionally, the occurrence of thunderstorms, often dry, led to the development of natural fires.
Machine learning methods for the detection of polar lows in satellite mosaics: major issues and their solutions
Authors: Krinitskiy M , Verezemskaya P , Elizarov S , Gulev S
Published: November 2020

Polar mesocyclones (PMCs) and their intense subclass polar lows (PLs) are relatively small atmospheric vortices that form mostly over the ocean in high latitudes. PLs can strongly influence deep ocean water formation since they are associated with strong surface winds and heat fluxes. Detection and tracking of PLs are crucial for understanding the climatological dynamics of PLs and for the analysis of their impacts on other components of the climatic system. At the same time, visual tracking of PLs is a highly time-consuming procedure that requires expert knowledge and extensive examination of source data.

There are known procedures involving deep convolutional neural networks (DCNNs) for the detection of large-scale atmospheric phenomena in reanalysis data that demonstrate a high quality of detection. However, one cannot apply these procedures to satellite data directly since, unlike reanalyses, satellite products register all the scales of atmospheric vortices. It is also known that DCNNs were originally designed to be scale-invariant. This leads to the problem of filtering of the scale of detected phenomena. There are other problems to be solved, such as low signal-to-noise ratio of satellite data, and an unbalanced number of negative (without PLs) and positive (where a PL is presented) classes in a satellite dataset.

In our study, we propose a deep learning approach for the detection of PLs and PMCs in remote sensing data, which addresses class imbalance and scale filtering problems. We also outline potential solutions for other problems, along with promising improvements to the presented approach.
Assessment of the global climate change impact on Fuel and Energy Complex infrastructure and adaptation opportunities in the Russian Arctic
Authors: Nefedova L V , Solovyev D A
Published: November 2020

The paper considers the problems and features of the functioning of the energy complex in the regions of the Russian Arctic under the influence of global climate change. Particular attention is paid to new ideas and developments intended for practical use in developing measures to adapt to the adverse effects of climate change. The issues of optimising the composition and structure of the energy economy of the Arctic territories in the areas of permanent residence, reducing the burden on natural ecosystems, and risks in the field of sustainable economic and social development of the Arctic region are discussed. The ways are proposed for developing new approaches to the formation of a strategy for the development of the region’s energy infrastructure under the influence of climatic and environmental factors on the natural environment. The mechanisms of the impact of changes in the climatic characteristics of the region on the operating conditions and the efficiency of energy facilities of the fuel and energy complex are determined. The degree of this dependence was studied for different types of infrastructure facilities of the fuel and energy complex. The data on the assessment of the impact of global climate change on the infrastructure of the fuel and energy complex and the possibilities for its adaptation, which include: the implications for power generation facilities; impact on energy transportation; problems of thawing permafrost and solifluction; climate impact on energy consumption and socio-economic effects; the role of distributed energy and renewable energy in adaptation to climate change. It is shown that for the territories of the Russian Arctic with isolated energy supply, the development of energy-efficient systems and renewable energy will reduce climate risks for sustainable growth. Not only of this power sector but the whole economic complex of the region due to both their better adaptation to the effects of climate change and the reduction of technogenic greenhouse gas emissions, which are one of the main factors of these changes.
Regionalization of the INM RAS global climate model data by the Polar WRF model in the Arctic
Authors: Rubinstein K G , Zarochentsev GA , Yu Ignatov R , Volodin E M , Iakovlev N G , Gritsun A S , Emelina S V
Published: November 2020

In this paper we present first results on the use of Polar WRF model for regionalization of the atmospheric circulation in the Arctic region produced by the global climate model INM-CM48 developed in INM RAS. We demonstrate that Polar WRF does not show run off effects in the first year of integration, gives reasonable results with respect to the global model with more details in the regions of complex topography and coast line.
Application of integral parametrization “SAIL” for climatology incoming shortwave radiation fluxes
Authors: Sinitsyn A , Gulev S
Published: November 2020

Along with field and satellite data, the calculation of fluxes using integral parameterizations can become a source of information about incoming shortwave radiation fluxes on the sea surface. In this work, we used the results of applying the SAIL parametrization created at the IO RAS, based on measurements of incoming shortwave radiation fluxes to the surface of the Atlantic Ocean and the corresponding meteorological parameters. The main task of such parameterizations is to construct climatology of shortwave radiation fluxes according to VOS data. In the course of the work, the new cloud climatology CLAAS ed.2 was used as input to calculate the average daily fields of the incoming shortwave radiation fluxes to the surface of the Atlantic Ocean. As reference data, we used a satellite database of shortwave radiation fluxes for the Atlantic Ocean - SARAH ed. 2. In conclusion, it can be noted that the SAIL parameterization works very well for a total cloud score of up to 4 octa. Further development of the SAIL parameterization is possible by separately taking into account the direct and diffuse flux of incoming shortwave radiation, since as part of the growth of possible cloud regimes, it is very important to know when the flux prevails over the diffuse and when vice versa.
Investigation and forecast of Sudden Stratospheric Warming events with chemistry climate model SOCOL
Authors: Tsvetkova N D , Vyzankin A S , Vargin P N , Lukyanov A N , Yushkov VA
Published: November 2020

To achieve better agreement of simulated Arctic winter stratospheric dynamic with observations assimilation procedure nudging was incorporated in CCM SOCOL. Trajectories based on SOCOL output winds demonstrate the reasonable agreement with trajectories based on reanalysis data inside the polar vortex and can be used for analysis and forecast of ozone related processes in winter-spring seasons. Obtained results of several recent major Arctic SSW events analysis show that CCM SOCOL could be used for SSW forecast over the period up to 8 days.
On integral characteristics of Polar Lows
Authors: Vazaeva N V , Chkhetiani O G , Kurgansky M V
Published: November 2020

Polar mesocyclones, also known as polar lows (PLs), are important maritime mesoscale (horizontal diameter up to 1000 km) weather systems at high latitudes, forming to the pole from the polar front. We consider the possible prognostic criteria of the PLs, in particular, the kinematic helicity as a squared characteristic related to the integral vortex formations and kinematic vorticity number. To calculate such characteristics we use reanalysis data and the results of numerical modeling with the WRF-ARW model for the PLs over the Nordic (Norwegian and Barents)seas. For comparison, experimental data are used. Our estimation of the helicity is based on its remarkable property – the connection of integral helicity content in the Ekman layer with the geostrophic wind velocity. Criteria associated with vorticity and helicity manifested through the PL genesis and development quite clearly. This criteria can be used to increase the efficiency and accuracy of complex forecasting techniques.
Impact of fine atmospheric scales on ocean eddies and deep convection in the Subpolar Northern Atlantic
Authors: Verezemskaya P S , Barnier B , Gavrikov A V , Gulev S K , Molines-Marc J-M
Published: November 2020

In this study we examine the sensitivity of the high-resolution regional ocean model solution to the atmospheric forcing of low (70 km - LoRes) and high (14 km - HiRes) spatial resolutions over the North Atlantic. To force the regional set up of NEMO ocean general circulation model (OGCM) we use the North Atlantic Atmospheric Downscaling (NAAD) product, which is the result of the Weather Research and Forecasting (WRF) atmospheric GCM with ERA-Interim as a boundary condition. Increase of the of the resolution of the atmospheric forcing and thus, representation of the surface turbulent heat and radiative fluxes in HiRes and LoRes atmospheric forcing, cause the 1.5° negative difference between sea surface temperature and -0.15 PSU in sea water salinity over the whole domain. The output of the OGCM forced by the high-resolution atmosphere is almost equal to the observational datasets. More intensive turbulent heat loss from the ocean surface and ventilation processes result in lower ocean heat content in the upper ocean (0-700 m) and at intermediate depth (700-1500 m) when the model is forced by HiRes. HiRes-driven experiment shows more intense coastal currents and less intensive large-scale currents. Ventilation processes are sensitive to the mesoscale atmospheric events representation: HiRes experiment provides deeper by 100 m mixed layer depths and its later in time deepening and restratification.
Controllable singular skeleton formation by means of the Kummer optical-vortex diffraction at a rectilinear phase step
Authors: Bekshaev Aleksandr , Chernykh Aleksey , Khoroshun Anna , Masajada Jan , Popiołek-Masajada Agnieszka , Riazantsev Andrii
Published: November 2020

We study positions and morphology of optical vortices (OVs) within the field obtained after transmitting a circular single-charged OV-beam through the transparent screen with a rectilinear π-phase step. Experimental results are obtained with the help of a programmable spatial light modulator which is used for the Kummer beam formation and for introduction of the π-step phase difference at a desirable position within the incident beam cross section. The theory based on the Kirchhoff–Fresnel approximation shows a good agreement with the experimental data; peculiar features of the Kummer beam diffraction are elucidated in the course of confrontation against the results involving the Laguerre–Gaussian beam model with the same transverse size and spherical wavefront component. The diffracted field contains a system of interacting OVs (singular skeleton) which demonstrate a regular evolution (migration) within the diffracted beam cross section while the π-phase step translates across the incident beam; depending on the step position, new OV pairs may emerge and/or annihilate in the topological reactions. The morphology parameters of the separate diffracted-field OVs (orientations and form-factors of the near-core equal-intensity ellipses) also depend on the stage of the OV evolution and indicate conditions favorable for the efficient trapping and guiding of microparticles. The results may be useful for the diagnostics of OVs, experimental measurements of phase objects and in micromanipulation techniques.
Geometric treatment of the radiation captured by the Large Millimeter Telescope (LMT/GTM) and ronchigrams at the caustic region for a static source
Authors: González-Juárez Adriana , Silva-Ortigoza Gilberto , Espíndola-Ramos Ernesto
Published: November 2020

The aim of the present work is to determine the reflected light rays, wavefronts, caustic and the ronchigram associated with the reflection phenomenon of a plane wave on a parabolic mirror, in particular on the parabolic antenna of the Large Millimeter Telescope (LMT/GTM). The results presented here are general in the sense that the incident plane wavefront has an arbitrary direction

I
ˆ

(
α
,
β
)

, determined by the angles α and β. We present numerical results for two different cases: (

α
=
π

/

200
,
β
=
0

) and (

α
=
π

/

10
,
β
=
0

). From these results we find that in general the caustic is a surface with a stable singularity of a hyperbolic umbilic type. For these cases we compute the distribution of the reflected light rays at some representative planes, determined by the form and dimensions of the caustic, then assuming that the ronchigrating is placed at those representative planes we compute the associated ronchigram. These results are important because they could describe the behavior of the light emitted by a static pointlike source located far away in the Universe.
Plasmonic properties of folded graphene nanodisks
Authors: Zhang Rui , Wang Shengchuan , You Bin , Han Kui , Shen Xiaopeng , Wang Weihua
Published: November 2020

Graphene and its relatives, such as bilayer and trilayer graphene, are promising plasmonic materials. Very recently, graphene has been demonstrated to be precisely folded (Chen et al 2019 Science
365 1036–40), thus folded graphene provides another appealing platform for plasmonics. In folded graphene nanodisks, we find fundamental dipole modes (DMs) will exhibit mode splitting, with one parallel and another perpendicular to the folding axis. The two DMs show differences in field patterns and folding angle dependence, but they both can be tuned by the size of structures and the Fermi level of graphene. Some interesting high order modes are introduced as well, which can be further engineered by folding. Our studies enrich the current research of graphene plasmonics, and pave the way for particular plasmonic device applications.
Polarized plasmon resonance spectra of electrochemically modified titanium surfaces with gold nanoparticles
Authors: Tcibulnikova Anna V , Khankaev Artemii A , Samusev Ilia G , Slezhkin Vasily A , Bryukhanov Valery V , Demin Maxim V , Myslitskaya Natalia A , Lyatun Ivan I , Medvedskaya Polina N
Published: November 2020

In this paper, the plasmon resonance on electrochemically modified titanium surfaces synthesized by anodic dissolution method has been studied in the presence with gold ablative nanoparticles. The permittivity functions and reflection coefficients of p- and s-polarized light spectra on the titanium oxide surface of various modification (roughness) have been analyzed. Spectral features of the negative refractive index in the area of surface plasmon generation on the rough titanium-oxide film interface have been also presented in this paper.
Experimental comparison of four nonlinear magnetic detection methods and considerations on clinical usability
Authors: van de Loosdrecht M M , Abelmann L , ten Haken B
Published: November 2020

Superparamagnetic iron oxide nanoparticles (SPIONs) are promising for clinical applications, because they have a characteristic nonlinear magnetic response when an external magnetic field is applied. This nonlinearity enables the distinct detection of SPIONs and makes measurements less sensitive to the human body and surgical steel instruments. In clinical applications, only a limited field strength for the magnetic detection is allowed. The signal to noise ratios (SNRs) of four nonlinear magnetic detection methods are compared. These methods include differential magnetometry and three variations of magnetic particle spectroscopy: frequency mixing, second harmonic detection and third harmonic detection. All methods were implemented on the same hardware and experimentally compared for various field strengths. To make the comparison fair, the same power was supplied to the excitation coil each time. In general, the SNR increases with increasing field strength. The SNR per drive field of all methods stabilizes or even decreases for field strengths above 6 mT. The second harmonic detection has the best SNR and the most room for improvement.
Erosion research of CX-2002U carbon composites under low-temperature high-flux hydrogen plasma
Authors: GUO Hengxin , YE Zongbiao , SHEN Bizhou , WEI Jianjun , WANG Bo , LUO Yuchuan , ZHANG Kun , GOU Fujun , CHEN Jianjun , CHEN Bo
Published: November 2020

The net erosion yield of CX-2002U carbon fiber composites under high-flux low-temperature hydrogen plasma is investigated using a linear plasma device. It is found that the net erosion yield decreases rapidly first, and then tends to saturate with the increase of hydrogen–plasma flux. When the temperature of the sample eroded by hydrogen plasma is above 300 °C, the hybridization of electrons outside the carbon atom would change. Then the carbon atoms combine with hydrogen atoms to form massive spherical nanoparticles of hydrocarbon compounds and deposit on the surface at the flux condition of 1.77 × 1022 m−2·s−1. Under the irradiation of hydrogen plasma loaded with negative bias, the surface morphology of the matrix carbon is changed dramatically. Moreover, the energy dependence of mass loss does not increase in proportion to the increase of hydrogen–plasma energy, but reaches a peak around 20 V negative bias voltage. Based on the analysis of different samples, it can be concluded that the enhancement of energy could make a contribution to chemical erosion and enlarge the size of pores existing on the surface.
Adhesional rolling behavior of micro-cylinder: Experimental observation of adhesional contacts and measurement of critical rolling resistance
Authors: Taoka Yuki , Watanabe Taihei , Iguchi Yoji , Hemthavy Pasomphone , Takahashi Kunio , Saito Shigeki
Published: November 2020

There has been much research offering theoretical explanations of rolling behavior considering the effect of adhesion, which is essential when the object is small. However, there has been a shortage of experimental verifications because objects are too small to manipulate and observe directly. This study measured the moment and observed the contact area before, during, and after rolling with an experimental setup on a relatively large scale. The experiment setup consisted of two glass cylinders which were placed in between two PDMS blocks. This paper reports three main findings: the results suggest that viscosity influences the transition of states of the contact. The critical rolling resistance is dependent on the radius of the cylinders and the applied weight to the cylinders. The results support the theoretical expectation of the value of a critical rolling resistance, which is the product of the radius of the cylinders and the work of adhesion. This study offers experimental foundations to develop theories of rolling of micro-cylinders.
Plastome phylogenomics ofCephalotaxus(Cephalotaxaceae) and allied genera
Authors: Ji Yunheng , Liu Changkun , Landis Jacob B , Deng Min , Chen Jiahui
Published: November 2020

Background and Aims

Cephalotaxus is a paleo-endemic genus in East Asia that consists of about 7–9 conifer species. Despite its great economic and ecological importance, the relationships between Cephalotaxus and related genera, as well as the interspecific relationships within Cephalotaxus, have long been controversial, resulting in contrasting taxonomic proposals in delimitation of Cephalotaxaceae and Taxaceae. Based on plastome data, this study aims to reconstruct a robust phylogeny to infer the systematic placement and the evolutionary history of Cephalotaxus.

Methods

A total of 11 plastomes, representing all species currently recognized in Cephalotaxus and two Torreya species, were sequenced and assembled. Combining these with previously published plastomes, we reconstructed a phylogeny of Cephalotaxaceae and Taxaceae with nearly full taxonomic sampling. Under a phylogenetic framework and molecular dating, the diversification history of Cephalotaxus and allied genera was explored.

Key Results

Phylogenetic analyses of 81 plastid protein-coding genes recovered robust relationships between Cephalotaxus and related genera, as well as providing a well-supported resolution of interspecific relationships within Cephalotaxus, Taxus, Torreya and Amentotaxus. Divergence time estimation indicated that most extant species of these genera are relatively young, although fossil and other molecular evidence consistently show that these genera are ancient plant lineages.

Conclusions

Our results justify the taxonomic proposal that recognizes Cephalotaxaceae as a monotypic family, and contribute to a clear-cut delineation between Cephalotaxaceae and Taxaceae. Given that extant species of Cephalotaxus are derived from recent divergence events associated with the establishment of monsoonal climates in East Asia and Pleistocene climatic fluctuations, they are not evolutionary relics.
Deciphering RNA modifications at base resolution: from chemistry to biology
Authors: Debnath Turja K , Xhemalçe Blerta
Published: November 2020

Nearly 200 distinct chemical modifications of RNAs have been discovered to date. Their analysis via direct methods has been possible in abundant RNA species, such as ribosomal, transfer or viral RNA, since several decades. However, their analysis in less abundant RNAs species, especially cellular messenger RNAs, was rendered possible only recently with the advent of high throughput sequencing techniques. Given the growing biomedical interest of the proteins that write, erase and read RNA modifications, ingenious new methods to enrich and identify RNA modifications at base resolution have been implemented, and more efforts are underway to render them more quantitative. Here, we review several crucial modification-specific (bio)chemical approaches and discuss their advantages and shortcomings for exploring the epitranscriptome.