bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low-threshold lasing in a plasmonic laser using nanoplate InGaN/GaN
Authors: Zhi Ting , Tao Tao , Liu Xiaoyan , Xue Junjun , Wang Jin , Tao Zhikuo , Li Yi , Xie Zili , Liu Bin 
Published: December 2021

Abstract
Plasmonic nanolaser as a new type of ultra-small laser, has gain wide interests due to its breaking diffraction limit of light and fast carrier dynamics characters. Normally, the main problem that need to be solved for plasmonic nanolaser is high loss induced by optical and ohmic losses, which leads to the low quality factor. In this work, InGaN/GaN nanoplate plasmonic nanolaser with large interface area were designed and fabricated, where the overlap between SPs and excitons can be enhanced. The lasing threshold is calculated to be ~6.36 kW/cm2, where the full width at half maximum (FWHM) drops from 27 to 4 nm. And the fast decay time at 502 nm (sharp peak of stimulated lasing) is estimated to be 0.42 ns. Enhanced lasing characters are mainly attributed to the strong confinement of electromagnetic wave in the low refractive index material, which improve the near field coupling between SPs and excitons. Such plasmonic laser should be useful in data storage applications, biological application, light communication, especially for optoelectronic devices integrated into a system on a chip.
Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD
Authors: Liu Shangfeng , Yuan Ye , Sheng Shanshan , Wang Tao , Zhang Jin , Huang Lijie , Zhang Xiaohu , Kang Junjie , Luo Wei , Li Yongde , Wang Houjin , Wang Weiyun , Xiao Chuan , Liu Yaoping , Wang Qi , Wang Xinqiang 
Published: December 2021

Abstract
In this work, based on physical vapor deposition and high-temperature annealing (HTA), the 4-inch crack-free high-quality AlN template is initialized. Benefiting from the crystal recrystallization during the HTA process, the FWHMs of X-ray rocking curves for (002) and (102) planes are encouragingly decreased to 62 and 282 arcsec, respectively. On such an AlN template, an ultra-thin AlN with a thickness of ~700 nm grown by MOCVD shows good quality, thus avoiding the epitaxial lateral overgrowth (ELOG) process in which 3–4 μm AlN is essential to obtain the flat surface and high crystalline quality. The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED, therefore significantly improving yields and decreasing cost.
Synthesis and characterization of ZnS-based quantum dots to trace low concentration of ammonia
Authors: Godavarti Uma Devi , Nagaraju P. , Yelsani Vijayakumar , Pushukuri Yamuna , Reddy P. S. , Dasari Madhavaprasad 
Published: December 2021

AbstractIn the present work, a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD, SEM, TEM with EDX, FTIR and gas sensing properties. XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure. TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm. SEM micrographs show spherical-shaped quantum dots. FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice. EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt (Co), zinc (Zn), oxygen (O), and sulphur (S) elements only and no other impurities are observed. The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70 °C. Hence, ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.
Breaking stress of Coulomb crystals in the neutron star crust
Authors: Kozhberov A A 
Published: December 2021

Abstract
It is generally accepted that the Coulomb crystal model can be used to describe matter in the neutron star crust. In [1] we study the properties of deformed Coulomb crystals and how their stability depends on the polarization of the electron background. The breaking stress in the crust σmax at zero temperature was calculated based on the analysis of the electrostatic energy and the phonon spectrum of the Coulomb crystal. In this paper, I briefly discuss the influence of zero-point, thermal contributions and the internal magnetic field on σmax.
Investigation of Faddeev variant of embedding theory
Authors: Kuptsov S. S. , Paston S. A. 
Published: December 2021

Abstract
Faddeev variant of embedding theory is an example of using the embedding approach for the description of gravity. In the original form of the embedding approach, the gravity is described by an embedding function of a four-dimensional surface representing our spacetime. In Faddeev variant, the independent variable is a non-square vielbein, which is a derivative of embedding function in embedding theory. We study the possibility of the existence of extra solutions in Faddeev variant, which makes this theory non-equivalent to GR. To separate the degrees of freedom corresponding to extra matter, we propose a formulation of this theory as GR with an additional contribution to the action. We analyze the equations of motion for a specific class of solutions corresponding to a weak gravitational field. We construct a simple exact solution corresponding to arbitrary matter and nontrivial torsion, which is an extra solution in Faddeev variant in the absence of real matter.
A search for variability of hard X-ray emission from the Vela pulsar wind nebula
Authors: Krassilchtchikov A M , Pshirkov M S , Bykov A M 
Published: December 2021

Abstract
Observations of hard X-ray emission from the Vela pulsar wind nebula (PWN) with the ISGRI camera aboard INTEGRAL gamma-ray observatory have been analysed with the aim to search for possible flux variability on scales from weeks to years, which could be caused by short-term evolution of pulsar wind structures similar to those governing sharp flares and flux depressions observed in the sub-GeV emission of the Crab PWN. No statistically significant flux depressions or flares have been found in none of the considered energy ranges: 20-50 keV, 50-100 keV, and 100-200 keV, however some hints of flux instability can be seen in the former two bands. If the variability of the pulsar wind termination surface or instabilities of turbulent magnetic field in the nebula predicted by a number of PWN models indeed influence the synchrotron spectrum of such objects, the variability of the 1-30 MeV emission from the Vela PWN could be checked with the next generation of gamma-ray facilities, like eASTROGAM or HERMES.
Reconstruction of solar activity based on14C and other isotope profiles in lunar regolith
Authors: Frolov D , Pavlov A , Ostryakov V , Konstantinov A , Vasilyev G , Kudryavtsev I , Dergachev V 
Published: December 2021

AbstractThe Moon might be considered as an integral detector of Galactic Cosmic Rays (GCR) as it contains on its surface cosmogenic isotopes produced by nuclear reactions. Since the retrieval of lunar regolith cores by Apollo missions, there were numerous attempts to measure concentrations and depth profiles of those isotopes and reconstruct the level of cosmic radiation at 1AU at various time scales, ranging from thousands to millions of years. The data also contains encoded levels of solar activity, as the Sun affects the differential flux of GCRs in a well-known manner. All those attempts showed that our nuclear interaction codes, GEANT4 for example, need corrections to describe the lunar data, be it tweaking of cross-sections or any other methods. There are also such archives on Earth: ice cores and trees. Based on terrestrial modulation potential reconstruction we try to calibrate GEANT4 code in a transparent manner, and also present our estimates on the solar activity on time scales of 0.02 and 3 Myrs. The estimates made using our calibration procedure show values consistent with modern understanding of history of solar modulation potential, and demonstrate the necessity to establish an agreed correction method for the analysis of lunar data. We also compare our results and method with another estimation of solar modulation potential during the last 1 Myr.
Beryllium Isotopes in the PAMELA Experiment
Authors: Bogomolov E A , Vasilyev G I , Menn W 
Published: December 2021

Abstract
Analysis of the isotopic composition of nuclei in galactic cosmic rays (GCR) in the orbital experiment of the PAMELA collaboration makes it possible to study the problems of the origin and propagation of cosmic rays in the Galaxy. The data of the PAMELA magnetic spectrometer, due to their high statistical and methodological accuracy, ensured significant progress in the study of the isotopic composition of light nuclei from H to Be in GCR in the energy range ~ 0.1-1 GeV/nucleon and for the first time made it possible to estimate the contribution to GCR of Local Interstellar Sources (LIS) from close (∼ 100 pc) of recent (~ million years) supernova explosions. To date, the isotopic composition of beryllium nuclei in GCR has been measured only for 7Be./9Be, 10Be/9Be ratios in the energy range of ∼ 100 MeV/nucleon in the space experiments IMP 7/8, Voyager, Ulysses, ACE/CRIS and for 10Be/9Be in balloon experiment with a superconducting magnet ISOMAX-98 for energies 0.2-1.0 and 1.1-2.0 GeV/nucleon. In this work, using flight data PAMELA 2006-2014, on the rigidity of the detected nuclei and their velocity (time-of-flight analysis and ionization losses in the multilayer calorimeter of the instrument), a new analysis of the isotopic composition of beryllium nuclei in the energy range of ~ 0.1-1.4 GeV/nucleon has been carried out. The results of isotopic analysis of beryllium nuclei in GCR (spectra 7Be, 9Be, 10Be and 7Be/9Be, 10Be/9Be - ratio depending on the rigidity and energy of nuclei) in comparison with the existing measurement and calculation data will be presented.
Stochastic analysis of dynamic processes in the solar activity
Authors: Kostina E Y , Khusaenova E V , Andreev A O , Hudec R , Nefedyev Y A 
Published: December 2021

Abstract
Natural processes existing in complex objects of inanimate and living matter are of a stochastic and non-equilibrium nature. The main problem in the study of such systems is to determine the value of entropy as a quantitative measure of the uncertainty and systematicity of states of dynamical systems in different phase spaces. This paper presents a new method for analyzing active processes of solar dynamics using the theory of non-Markov random discrete processes (NMRDP). The NMRDP theory is based on the Zwanzig-Mori kinetic equations in a finite-difference discrete interpretation. This is consistent with the concept of non-equilibrium statistical condensed matter physics. Qualitative information about the set of behavioral patterns, relaxation processes, dynamic characteristics and internal properties of solar activity can be obtained using NMRDP modeling by the author’s methodological approach developed in this work. This approach is focused on the analysis of spectral frequency memory functions, dynamic orthogonal parameters, phase transformations, relaxation and kinetic processes and self-organization in complex physical systems. In this work, for modeling NMRDP, the author’s software package APSASA (automated program for solar activity stochastic analysis) was used, which also allows predicting the trend of solar activity for a limited period of time. Modeling NMRDP associated with active processes occurring on the Sun made it possible to build a mathematical model with whose help it is possible to study the regularities and randomness of stochastic processes, as well as to reveal the patterns arising from the recurrence and periodicity of solar activity.
Analysis of modern observations of meteor showers based on PTM methods
Authors: Sharafutdinova A A , Andreev A O , Nefedyev Y A , Hudec R , Demina N Y 
Published: December 2021

Abstract
The work is focused on the analysis of modern observations of meteoroids included in the data bank formed by both professional researchers and amateur astronomers. Based on the modern physical theory of meteoroids (PTM), a new method for analyzing measurements developed, which provides the accuracy comparable with the results of radar observations. Due to the fact that the accuracy of the new method for analyzing meteoroids observations has increased significantly, it became possible to process observations of the Perseid and Leonid showers over a period of 120 years. The use of PTM made it possible for the first time to explain the distribution of meteor echo signals observed at an altitude of 2 MHz, at which the upper part of this distribution refers to an altitude of 140 km. In the process of work, a database of orbital characteristics of meteoroids was created. A method has been developed for modeling the probability of hitting a certain area of a meteor particle with a mass greater than a certain specified value and determining the density of a meteor shower from radio observations as well as a new “tomography” method for calculating the density distribution of sporadic meteors in the sky using radar observations of meteors at the same station with a goniometer. The method allows calculating the density of a meteor shower on the celestial sphere with an angular resolution of 2°. The use of these methods served as a proof that the distribution density of meteoroid showers on the celestial sphere has two planes of symmetry: the first coincides with the plane of the ecliptic, passing through the poles of the Earth, the other one is perpendicular to the plane of the ecliptic.
Changes in solar activity based on radiocarbon data and climate variations in the interval 8000 - 1000 BC
Authors: Dergachev V A , Kudryavtsev I V 
Published: December 2021

AbstractThis work examines the change in the activity of the Sun based on the reconstruction of the heliospheric modulation potential in the time interval 8000 - 1000 BC. Reconstructions of this potential were obtained using radiocarbon data, taking into account the influence of changes in the Earth’s climate. A comparison is made of the variations in the activity of the Sun with the global surface temperature. It is shown that variations in global temperature during this period could be the result of changes in solar activity. So high solar activity could lead to recorded temperature maximums around 7000 and 5300 BC. The drop in temperature in the range 3000-1000BC could be the result of low solar activity.
Development of detector pixels based on silicon photomultipliers for the Cherenkov gamma-ray telescope TAIGA-IACT
Authors: Bogdanov A A , Tuboltsev Yu V , Chichagov Yu V , Krassilchtchikov A M 
Published: December 2021

Abstract
The design and scheme of signal readout from silicon photomultipliers OnSemi MicroFJ-60035 used as sensitive elements (pixels) of a new detector cluster for the camera of the Cherenkov gamma-ray telescope TAIGA-IACT are developed. The design of the developed pixel follows the shape of the photomultiplier tube XP1911 using in the first generation clusters, and that provides compatibility of the new cluster with the telescope camera. Due to the adjustable gain, the developed scheme allows one to detect and digitize signals in a wide dynamic range from several to 10 000 photons.
Influence of non-gravitational effects on the Centaur upper stage of the Surveyor 2 spacecraft
Authors: Martyusheva A A , Devyatkin A V 
Published: December 2021

Abstract
A small near-Earth asteroid, discovered by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) on September 17, 2020, turned out to be a part of the Centaur upper stage of the Surveyor 2 spacecraft launched by NASA on September 20, 1966 and subsequently crashed. This object had moved in a heliocentric orbit until it was under the influence of Earth’s gravitational field. As a result, a close approach to the Earth took place at a distance of about 50000 km on December 1, 2020. Despite the fact that the Centaur escaped back into a new orbit around the Sun in March 2021, it is of special interest for research, in particular, to consider the impact of non-gravitational effects on its orbital characteristics. Thus, it was calculated that the maximum displacement of the object trajectory due to the influence of solar radiation pressure over 15 years (the next close approach will take place in 2036) can be about 10.3-13.5 km, depending on the albedo. Estimations of the Yarkovsky effect showed that the magnitude of the expected change in the semi-major axis of Centaur’s orbit is from -8.1 • 10−13 to 1.6 10−13, depending on the angle of its rotation.
Meteorite hazard model for a space mission to Mars
Authors: Demina N Y , Andreev A O , Nefedyev Y A 
Published: December 2021

Abstract
Currently, for the world’s space agencies, the robotic exploration of Mars is one of the most important tasks. One of the necessary stages for the implementation of this mission is the development and addition of new information to the State standard “Meteoric substance, spatial distribution model”. Until now, the State Standard has been more detailed in comparison with the American analogue (developed by NASA) and the European one. The standard is a mandatory document in the design of spacecraft. It should be noted that modeling of meteor hazard at a distance from Earth to Mars is a complex problem, since the analysis of the meteor population in near-Earth space does not give a complete picture of the propagation of meteoroids along the Earth-Mars route. Moreover, the further the trajectory of the spacecraft from the Earth’s orbit is, the less the number of near-Earth meteorites becomes. That is, objects that have the same orbital parameters with small bodies crossing the Earth’s orbit. The only way to solve this problem is to build an interpolation regression model, which is based on measurements from the Earth’s surface and observations of space missions. For this purpose, the density of sporadic meteoroids was transformed from the space mission coordinate system to the ground one. This was done in order to analyze meteorite observations by the Mariner 4 and Pioneer 10 spacecrafts. The results of the work made it possible to obtain new data for the spatial distribution of meteoroids on the Earth-Mars path. According to a comparison of our data with the data on the density of space debris in the previous works the most safe for space flights are normalization conditions of distributions of the elements of the orbits of meteoric bodies P(Z, e, i) < 60.
Composition of the lunar mantle for lower mantle high-velocity seismic model
Authors: Kronrod E V , Kronrod V A , Kuskov O L , Nefedyev Y A , Andreev A O 
Published: December 2021

Abstract
We investigated models of the internal structure of initially homogeneous Moon differentiated as a result of partial melting, using data on seismic velocities according to the seismic models assume the zonal structure of the lunar mantle is a model of the Moon which was obtained with using the array processing methods of high velocities in the lower mantle. As a result of inversion of gravity (mass, moment of inertia), seismic (P- and S-waves velocities) and petrological (balance ratios) data, the Monte Carlo method was used to reconstruct the chemical composition and internal structure of the Moon. The phase composition and physical properties of the mantle were obtained with Gibbs free energy minimization method and equations of state in the five-component system CaO-FeO-MgO-Al2O3-SiO2. For all models, possible values of seismic velocities and concentrations of the main oxides in three zones of the mantle were obtained, satisfying the geochemical and geophysical constraints and the possible sizes of the Fe-10%S core were determined. It was found that the lunar mantle chemical composition (concentration of FeO, Al2O3 and CaO) differs depending on the mantle zone. Constraints on the values of seismic velocities in the lower mantle and the most probable size of the lunar core were determined: VP ≤ 8.45 km/s; Fe-10%S core radius is ∼360 km.
3D printing technologies for creating models and nozzles in an aerodynamic shock tunnel experiment
Authors: Kotov M A , Monakhov N A , Poniaev S A , Popov P A , Tverdokhlebov K V 
Published: December 2021

Abstract
The features of 3D printing method for rapid prototyping and manufacturing of models for a pulsed high-speed gas-dynamic experiment are considered. Modern additive technologies allow the production of models. The basic properties of the materials and the advantages of 3D printing methods are described. The structure and properties of the obtained models can be unattainable using traditional manufacturing techniques. The design of the wind tunnel nozzle block is considered, which provides for the production of profiled contours using 3D printing. The advantages and disadvantages of use of such units on the shock tube are considered.
Search for possible connections of the h-Virginids meteor shower with near-Earth asteroids
Authors: Sergienko M V , Sokolova M G , Andreev A O , Nefedyev Y A 
Published: December 2021

Abstract
Asteroids and comets are the oldest objects in the Solar System and contain the initial matter that existed at the moment of its formation. By studying those small celestial bodies one may describe the processes taking place at the early stages and conditions of the formation of the Solar System. The study of the genetic relationships (using metrics based on orbital elements) of meteor showers with parent bodies (asteroids and comets) can be used to develop the theory of evolutionary processes that took place at the time of the formation of the solar system. In this work, we have studied the genetic relationships of the small meteor shower of the h-Virginids (HVI) with the near-Earth asteroids of the Apollo group. An author’s multi-factor method is applied, which implies the use of D-criterion by Drummond, metric by Kholshevnikov, Tisserand’s parameter, μ and ν quasi-stationary parameters of the restricted three-body problem, and the analysis of the orbit’s perihelion longitude π. The observational base includes television catalogues meteor orbits that are in the public domain: Meteoroid Orbit Database v2.0 (2010–2012) (CAMS) and the European meteor network EDMOND (2001–2016) catalogues. As a result of this study, the orbit of the h-Virginids (HVI), according to the values of Tisserand’s parameter, was found to be transitional, and thus, it was impossible to identify whether it was of cometary or of asteroid type. Using the author’s method, the asteroids 2001SZ269 and 2014HD19 were distinguished. The 2001SZ269 asteroid was distinguished as a candidate having a possible connection with the h-Virginids’ parent body.
FNS-parameterization of human magnetoencephalograms for the diagnosis of photosensitive epilepsy
Authors: Khairullina R R , Demin S A , Yunusov V A , Panischev O Y 
Published: December 2021

Abstract
This work presents the results of parameterization of magnetoencephalogram signals from healthy subjects and a patient with photosensitive epilepsy. Diagnostic criteria were established during the extraction of resonant and high-frequency (chaotic) components of the initial time signals. It is shown that an increase in the intensity of the chaotic components of the studied signals in the high-frequency region leads to a violation of cross-correlation relationships and a decrease in the level of manifestation of frequency-phase synchronization. The discovered signs of photosensitive epilepsy will contribute to the development of new methods for the diagnosis and medical control of this disease based on Flicker-Noise Spectroscopy.