bluuebunny/crossref_metadata_2025 huggingface dataset:
Linear bounded potential model for semiconductor band bending
Authors: Villavicencio F , Ferreyra J M , Bridoux G , Villafuerte M
Published: January 2022

We propose a simple but unexplored model for the semiconductor band bending with the aim to obtain a relatively simple expression to calculate the energy spectrum for the confined levels and the analytical expressions for wave-functions. This model consists of a linear potential but it is bounded or trimmed in energy unlike the well known wedge potential (WP) model. We present exact solutions for this potential in the frame of the effective mass approximation and they are valid for electron or hole confinement potential. This model provides a more adequate physical scenario than the WP since it takes into account the charge balance involved in the band bending potential. These results allow to treat confined potential problems as in the case of a two-dimensional electron gas in a simplified way. We discuss the application of this approximation to the recombination time of electrons an holes and for the Franz–Keldysh effect.
Self-generated quantum gauge fields in arrays of Rydberg atoms
Authors: Ohler Simon , Kiefer-Emmanouilidis Maximilian , Browaeys Antoine , Büchler Hans Peter , Fleischhauer Michael
Published: January 2022

As shown in recent experiments (Lienhard et al 2020 Phys. Rev. X 10 021031), spin–orbit coupling in systems of Rydberg atoms can give rise to density-dependent Peierls phases in second-order hoppings of Rydberg spin excitations and nearest-neighbor repulsion. We here study theoretically a one-dimensional zig-zag ladder system of such spin–orbit coupled Rydberg atoms at half filling. The second-order hopping is shown to be associated with an effective gauge field, which in mean-field approximation is static and homogeneous. Beyond the mean-field level the gauge potential attains a transverse quantum component whose amplitude is dynamical and linked to density modulations. We here study the effects of this to the possible ground-state phases of the system. In a phase where strong repulsion leads to a density wave, we find that as a consequence of the induced quantum gauge field a regular pattern of current vortices is formed. However also in the absence of density–density interactions the quantum gauge field attains a non-vanishing amplitude. Above a certain critical strength of the second-order hopping the energy gain due to gauge-field induced transport overcomes the energy cost from the associated build-up of density modulations leading to a spontaneous generation of the quantum gauge field.
X-ray flares raising upon magnetar plateau as an implication of a surrounding disk of newborn magnetized neutron star
Authors: Zheng Tian-Ci , Li Long , Zou Le , Wang Xiang-Gao
Published: January 2022

The X-ray flares have usually been ascribed to long-lasting activities of the central engine of gamma-ray bursts (GRBs), e.g., fallback accretion. The GRB X-ray plateaus, however, favor a millisecond magnetar central engine. The fallback accretion can be significantly suppressed due to the propeller effect of a magnetar. Therefore, if the propeller regime cannot resist the mass flow onto the surface of the magnetar efficiently, the X-ray flares raising upon the magnetar plateau would be expected. In this work, such peculiar cases are connected to the accretion process of the magnetars, and an implication for magnetar-disc structure is given. We investigate the repeated accretion process with multi-flare GRB 050730, and give a discussion for the accretion-induced variation of the magnetic field in GRB 111209A. Two or more flares exhibit in the GRB 050730, 060607A and 140304A; by adopting magnetar mass M = 1.4 M
⊙ and radius R = 12 km, the average mass flow rates of the corresponding surrounding disk are 3.53 × 10−4
M
⊙ s−1, 4.23 × 10−4
M
⊙ s−1, and 4.33 × 10−4
M
⊙ s−1, and the corresponding average sizes of the magnetosphere are 5.01 × 106 cm, 6.45 × 106 cm, and 1.09 × 107 cm, respectively. A statistic analysis that contains eight GRBs within 12 flares shows that the total mass loading in single flare is ∼ 2 × 10−5
M
⊙. In the lost mass of a disk, there are about 0.1% used to feed a collimated jet.
Spatially resolved properties of supernova host galaxies in SDSS-IV MaNGA
Authors: Zhang Hong-Xuan , Chen Yan-Mei , Shi Yong , Bao Min , Yu Xiao-Ling
Published: January 2022

We crossmatch galaxies from Mapping Nearby Galaxies at Apache Point Observatory with the Open Supernova Catalog, obtaining a total of 132 SNe within MaNGA bundle. These 132 SNe can be classified into 67 Type Ia and 65 Type CC. We study the global and local properties of supernova host galaxies statistically. Type Ia SNe are distributed in both star-forming galaxies and quiescent galaxies, while Type CC SNe are all distributed along the star-forming main sequence. As the stellar mass increases, the Type Ia/CC number ratio increases. We find: (1) there is no obvious difference in the interaction possibilities and environments between Type Ia SN hosts and a control sample of galaxies with similar stellar mass and SFR distributions, except that Type Ia SNe tend to appear in galaxies which are more bulge-dominated than their controls. For Type CC SNe, there is no difference between their hosts and the control galaxies in galaxy morphology, interaction possibilities as well as environments; (2) compared to galaxy centers, the SN locations have smaller velocity dispersion, lower metallicity, and younger stellar population. This is a natural result of radius gradients for all these parameters. The SN location and its symmetrical position relative to the galaxy center, as well as regions with similar effective radii have very similar [Mg/Fe], gas-phase metallicity, gas velocity dispersion and stellar population age.
A new expansion of planetary disturbing function and applications to interior, co-orbital and exterior resonances with planets
Authors: Lei Han-Lun
Published: January 2022

In this study, a new expansion of planetary disturbing function is developed for describing the resonant dynamics of minor bodies with arbitrary inclinations and semimajor axis ratios. In practice, the disturbing function is expanded around circular orbits in the first step and then, in the second step, the resulting mutual interaction between circular orbits is expanded around a reference point. As usual, the resulting expansion is presented in the Fourier series form, where the force amplitudes are dependent on the semimajor axis, eccentricity and inclination, and the harmonic arguments are linear combinations of the mean longitude, longitude of pericenter and longitude of ascending node of each mass. The resulting new expansion is valid for arbitrary inclinations and semimajor axis ratios. In the case of mean motion resonant configuration, the disturbing function can be easily averaged to produce the analytical expansion of resonant disturbing function. Based on the analytical expansion, the Hamiltonian model of mean motion resonances is formulated, and the resulting analytical developments are applied to Jupiter’s inner and co-orbital resonances and Neptune’s exterior resonances. Analytical expansion is validated by comparing the analytical results with the associated numerical outcomes.
Analysis of the Distribution, Rotation and Scale Characteristics of Solar Wind Switchbacks: Comparison between the First and Second Encounters of Parker Solar Probe
Authors: Meng Ming-Ming , Liu Ying D. , Chen Chong , Wang Rui
Published: January 2022

The S-shaped magnetic structure in the solar wind formed by the twisting of magnetic field lines is called a switchback, whose main characteristics are the reversal of the magnetic field and the significant increase in the solar wind radial velocity. We identify 242 switchbacks during the first two encounters of Parker Solar Probe. Statistics methods are applied to analyze the distribution and the rotation angle and direction of the magnetic field rotation of the switchbacks. The diameter of switchbacks is estimated with a minimum variance analysis (MVA) method based on the assumption of a cylindrical magnetic tube. We also make a comparison between switchbacks from inside and the boundary of coronal holes. The main conclusions are as follows: (1) the rotation angles of switchbacks observed during the first encounter seem larger than those of the switchbacks observed during the second encounter in general; (2) the tangential component of the velocity inside the switchbacks tends to be more positive (westward) than in the ambient solar wind; (3) switchbacks are more likely to rotate clockwise than counterclockwise, and the number of switchbacks with clockwise rotation is 1.48 and 2.65 times those with counterclockwise rotation during the first and second encounters, respectively; (4) the diameter of switchbacks is about 105 km on average and across five orders of magnitude (103–107 km).
Physical Properties of 29 sdB+dM Eclipsing Binaries in Zwicky Transient Facility
Authors: Dai Min , Chen Xiao-Dian , Wang Kun , Luo Yang-Ping , Wang Shu , Deng Li-Cai
Published: January 2022

The development of large-scale time-domain surveys provides an opportunity to study the physical properties as well as the evolutionary scenario of B-type subdwarfs (sdBs) and M-type dwarfs (dMs). Here, we obtained 33 sdB+dM eclipsing binaries based on the Zwicky Transient Facility (ZTF) light curves and Gaia Early Data Release 3 (EDR3) parallaxes. By using the PHOEBE code for light curve analysis, we obtain probability distributions for parameters of 29 sdB+dMs. R
1, R
2 and i are well determined, and the average uncertainty of mass ratio q is 0.08. Our parameters are in good agreement with previous works if a typical mass of sdB is assumed. Based on parameters of 29 sdB+dMs, we find that both the mass ratio q and the companion’s radius R
2 decrease with the shortening of the orbital period. For the three sdB+dMs with orbital periods less than 0.075 days, their companions are all brown dwarfs. The masses and radii of the companions satisfy the mass–radius relation for low-mass stars and brown dwarfs. Companions with radii between 0.12 R
⊙ and 0.15 R
⊙ seem to be missing in the observations. As more short-period sdB+dM eclipsing binaries are discovered and classified in the future with ZTF and Gaia, we will have more information to constrain the evolutionary ending of sdB+dMs.
Improving the compact heat exchangers with profiled tubes for marine power plants
Authors: Naumenko A V , Lychakov V D , Egorov M Yu , Shcheglov A A , Matyash A S , Borisov A O , Balunov B F
Published: January 2022

The design features of heat exchangers with flat tubes are considered. The stages of creating a new flat tube and its prototypes are analyzed. An oil refrigerator is chosen as a prototype of the heat exchanger because of the previous use of flat tubes with wells, now replaced with new flat profiled tubes. Thermal and hydraulic tests of a refrigerator made of such tubes are carried out at the stand. During the testing, the hydraulic resistance of the cavities of the cooled and cooling media and thermal parameters are determined: heat power, heat transfer coefficient and heat transfer coefficient from the cooled medium in the inter-tube cavity with the transverse flow of tubes to the tube wall. A satisfactory correspondence of the actual power values determined for both working environments has been established. The discrepancy does not exceed (-7.6%)-(+5%) with an average value of +0.2%. A satisfactory correspondence of the actual and calculated values of the refrigerator power has been obtained. The discrepancy does not exceed (-15%)-(+9%) with an average value of -2.8%. The calculation of the capacity of the refrigerator during its operation in the design mode of oil cooling is carried out. The oil flow is considered both through the pipe and through the inter-pipe space. A good convergence of the calculations with the experimental results has been revealed.
Development of the design of a new working section cooled by a dispersed coolant flow for a stand with induction heating
Authors: Dedov A V , Komov A T , Shteling V S , Shcherbakov P P , Iliyn V V , Zakharenkov A V
Published: January 2022

The paper presents a description of the design of a new working section cooled by a dispersed coolant flow for a stand with induction heating. The choice of the material of the working area and the method of spraying has been substantiated. The first commissioning experiments were carried out in a stationary cooling mode, with the parameters of the coolant p = 1.7 · 105 Pa, G = 3.8 · 10-3 kg/s.
Design Optimization of a Helical Coil Gas Cooler Based on the Results of CFD Modeling of Erosion Wear
Authors: Mikula V A , Maslennikov G E , Bogatova T F
Published: January 2022

Simulation of erosion wear and design optimization have been performed for a convective gas cooler with a helical coil. Based on the results of simulation of the standard gas cooler design with a flat baffle used in Shell gasification-based combined cycle unit, it is concluded that the particle impact angle is the main factor determining the erosion maximum. To reduce erosion, it is necessary to install a structural element instead of the flat baffle to align the flow path of ash particles at the inlet to the gas cooler. The results of simulation for various baffle shapes show that a hemispherical baffle is optimal. The use of a hemispherical baffle plate made it possible to align the ash particle flow path at the inlet to the gas cooler channels and reduce the maximum level of erosion by a factor of almost 4 compared to the standard geometry of the baffle plate.
Displacement of oil by SiO2-nanofluid from a microporous medium: microfluidic experiments
Authors: Pryazhnikov A I , Minakov A V , Pryazhnikov M I , Zhigarev V A , Nemtsev I V
Published: January 2022

In this work, the process of displacing oil from a microfluidic chip that simulates a porous medium is studied. Experimental photographs of the process of oil displacement by water and SiO2-nanofluid are presented. It is shown that the use of nanofluid increases the oil displacement efficiency by 16%.
Circulation management in hot water supply systems
Authors: Rotov P V , Sivukhin A A , Rotova M A , Gafurov R A , Gorshkov A V
Published: January 2022

The compliance of the actual heat consumption for heating cold water for public hot water supply service with the approved standard has been analyzed. Using passive engineering experiments, we studied the operating modes of hot water supply systems for several groups of houses, in which different methods for regulating water consumption in hot water supply systems were used. Data were collected using online energy monitoring and commercial metering system. Features of the static and dynamic load regulation of hot water systems have been investigated. The effect of methods for regulating the heat load of hot water supply systems on their actual heat consumption has been analyzed. An assessment has been made of the possibility of bringing the actual operating mode of the hot water systems to the specified value which is the basis for calculating the consumption rate. Ways to improve the efficiency of hot water supply systems have been determined. Conclusions have been drawn concerning the need to revise the standardized indicators of hot water quality and adjust the methodology for calculating the consumption rate in hot water supply systems.
Research on the Impact of Recycled Asphalt Mixture on Road Performance Based on New Thermal Recycling
Authors: Yin Peng , Xie Yuanguang , Lang Huixi
Published: January 2022

Different binder content to RAP Regeneration SBS modified asphalt mixture for road performance to SBS modified asphalt (I-D type) as an index, determine the optimum dose of new heat regenerating agent and different RAP regeneration, and prepared different recycled asphalt, which have differences in RAP content. The performance of recycled asphalt mixture with different RAP content was evaluated by freeze-thaw splitting test. Rut test and Low temperature trabecular bending test. The correlation between RAP content and pavement performance was analyzed by grey system correlation analysis method. According to the experimental verification results, it can be known that increasing the content of RAP material can improve the high-temperature performance of reclaimed asphalt, but will result in a qualitative decrease in low-temperature performance and water temperature, but the above-mentioned performance can reach the required level, Shows that new heat regenerators play a role in the road performance of RAP materials, and for the RAP material utilization ratio of more than 50%, as for the gray correlation analysis, it can be found that there is a close correlation between the low-temperature performance of recycled asphalt mixture and the content of RAP material. The low temperature cracking resistance of asphalt mixtures will change significantly due to the slight changes in RAP materials.
Optimization of Mechanically Assembled Van Der Waals Heterostructure Based On Solution Immersion and Hot Plate Heating
Authors: Lei Xunyong
Published: January 2022

Layers of two-dimensional material are bonded together by van der Waals force, as a result, there is no need to take into consideration of the lattice mismatch in the formation of heterojunction, which is endowed with the characteristics of simple stacking in method, free of limitation to the type of materials and diverse changes. However, although the Van Der Waals heterojunction is relatively easy to stack, it is still difficult to generate inter-layer coupling between the thin crystal layers that form the Van Der Waals heterojunction. In most cases, the stacked heterojunction is simply stacked together without any new effects. Therefore, the realization of heterojunction coupling is a difficult problem to be considered in the process of preparing Van Der Waals heterojunction. In this paper, a method based on solution immersion and hot plate heating is proposed to optimize the mechanical stacking of Van Der Waals heterojunctions. It is found that the heterojunctions prepared by normal mechanical stacking method are usually uncoupled before treatment, but they can be stably coupled after treatment. Our method, simple, fast with low-cost, has been repeatedly verified to have a high success rate of coupling, which is suitable for most experimental groups to use and reproduce.
Sand Control Technology for Low pressure Lost-Circulation Wells and Application in South Sudan
Authors: Wen Yong , Li Huaiwen , Zhu Yingbin , Song Zhiyong , Wang Yanshan , Jin Jiuxiang
Published: January 2022

A kind of plugging proppants was developed for solving the problem of ‘easy to lose sand’, resulting in difficult sand control in low pressure lost-circulation wells in South Sudan Oilfield. The proppants can cement together to form a consolidated body with certain strength (≥2 MPa) and permeability (≥1.3 μm2) in oil layers. The body can temporarily plug lost circulation channels. Meanwhile, a supporting sand-adding tool was developed to simplify the proppants squeezed process, and a sand-carrying fluid was optimized to improve sand suspension performance and protect pay zones in low pressure lost-circulation wells. These measures formed a sand control technology for low pressure lost-circulation wells. 12 wells have been successfully applied in South Sudan Oilfield and achieved good effect on increasing oil production by 15 t/d.
Research On the Fractal Dimensions of the Organic-Rich Shale Pores Via Different Models
Authors: Dai Fangyao
Published: January 2022

Fractal dimension can be used to the pore surface characterize. For pore structures in different sizes, the calculation models of fractal theory should be distinguished due to the different principles of the gas adsorption experiments. To further study the adaptability of the fractal model for gas adsorption experimental data, the author collected shale samples of Longmaxi formation from Well JY1, then CO2 and N2 adsorption provided the PSD curves. In addition, the fractal dimensions of micropore and mesopore were calculated by the Jaroniec fractal model and Frenkel–Halsey–Hill (FHH) fractal model respectively. The research shows that the Jaroniec model may be suitable to calculate CO2 adsorption data and could characterize the fractal dimension of micropore, while the FHH model may be suitable to calculate N2 adsorption data in the high relative pressure region. It suggests that the micropore and mesopore could have different dimensions and the evaluation of the structure in shale pores should consider both of them.
MPPT Control Strategy of Photovoltaic Cells Based on Duty Cycle Disturbance
Authors: Xu Ting , Gong Xin , Liang Longkai
Published: January 2022

Photovoltaic cell is a key part of solar power generation system, and whether its photoelectric conversion is sufficient is also called the maximum power point tracking problem, that is, photovoltaic cell MPPT. Different from the traditional MPPT control algorithm, this paper models and analyzes the output characteristics of solar cell. on this basis, proposes a fuzzy control algorithm based on duty cycle disturbance, and simulates it with MATLAB. The result shows the algorithm can well take into account the tracking speed and control accuracy when the external environment change.
Mechanism of Lithium Dendrites Formation and Suppression Strategies in Li Metal Batteries
Authors: Xu Zhiyu
Published: January 2022

This paper describes and summarizes the modifying progress established on Li metal anode in recent years. With the increasing demand for high-capacity batteries, Li-ion batteries, one of the most commercialized batteries, can no longer meet the demand. Thus, the high-energy-density lithium metal battery using lithium metal as anode is widely researched due to the lowest electrochemical potential (-3.04 V) of lithium and ultimate theoretical capacity (3860 mAh/g). However, the Li dendrites formation becomes the main obstacle for the commercialization as it will trigger thermal runaway and short circuit. In this paper, the growth process of Li dendrites was discussed, and various modifying solutions based on electrolytes, Li alloy and current collectors to suppress Li dendrites were summarized.
Progress in Structure Determination, Reaction and Classification of Organic Compounds
Authors: Ruan Qiao , Kong Qing-Xin , Li Qing , Tan Xiao-Li , Lu Jun
Published: January 2022

In recent years, with the continuous development of synthetic organic chemistry, a large number of new compounds are synthesized every year. Many of these compounds not only have novel structures, but also have complex structures. The traditional four spectral analysis methods are difficult to understand its spatial structure clearly and comprehensively. At the same time, with the understanding of the spatial structure of related compounds, it is possible to further explore the relationship between the structure and properties of compounds. This paper analyzes different kinds of organic compounds, including nitrogen-containing organic compounds, polycyclic aromatic hydrocarbons and volatile organic compounds. The detection methods of volatile organic compounds and derivatization chromatography were discussed. Through VOC test, the results show that the average concentration of each substance decreases with time.
High-Temperature Property Evaluation and Index Research of Modified Asphalt before and After Aging
Authors: Wang Wen , Wang Zihao , Guo Liujie
Published: January 2022

In order to better evaluate the composite modified asphalt of composite modified asphalt, this study through dynamic shear rheological (DSR) test, the three kinds of polymer modified asphalt before and after ageing: the compound modified asphalt (CCR), rubber powder modified asphalt (CR) and composite modified asphalt of SBS modified asphalt (SBS) analysis, to explore suitable for composite modified asphalt of modified asphalt evaluation index. The results show that: Compared with G*/sinδ, G*/(sinδ)9 has higher accuracy for evaluating the composite modified asphalt of polymer modified asphalt and is more sensitive to changes in phase angle. The critical temperature of anti-rutting factor TG*/sinδ9 is significantly higher than that of TG*/sinδ, especially for composite modified asphalt. This has an important impact on the PG classification in the Superpave asphalt binder specification. G*/sinδ underestimates the high temperature grade of the modified asphalt. The equivalent viscosity measured with η’ = sinδ-4.8628 G*/ω has the best correlation with the anti-rutting factor G*/(sinδ)9, and the highest correlation coefficient is 0.999, which is more suitable as a high-temperature property evaluation index of modified asphalt.
Carbon-Based Micro/Nano Devices for Transistors, Sensors, and Memories
Authors: Lin Guida
Published: January 2022

The ballistic transport of electrons and unique structural characteristics of graphene and carbon nanotubes enable them to play an important role in nano electronical appliances. Nanodevices based on carbon nano materials can further reduce device size without affecting performance. Here, this paper analyzes Fin Field-effect transistor (FinFET) and Tunnel Field-effect transistor (TFET) based on graphene nanoribbon (GNR) and carbon nanotube which could be used for reducing power consumption. Then it summarizes the applications of graphene in micro/nano sensors based on the electrical, mechanical, optical, and thermal properties of graphene. Graphene’s single-atom thickness and charge storage mechanism provide itself with great potential in the field of resistive memory. Graphene is also widely used in flexible electronic devices.
Research Progress in Preparation, Stability and Application of Nanoemulsion
Authors: Zhou Yue
Published: January 2022

Nanoemulsion has excellent functional characteristics, it is widely applied in medicine, food, cosmetics, agriculture and other fields, thus gradually becoming hit issue in scientific research. This article combines various literature reports around the world. In order to provide reference for further research and development of nanoemulsion, we thoroughly analyze the preparation technology, composition, stability mechanism and the factors affecting its stability, and summarize the application of nanoemulsion in the food field.
Purification of Copper-Containing Wastewater in Inner-Cooling Oil Channel of Piston with Magnesium Hydroxide
Authors: Ma Lan , Lian Weijie , Wu Huiming , Zhang Lijun , Zhai Yuxin
Published: January 2022

The treating fluid in the piston of inner-cooling oil channel is acid wastewater containing copper ion, it would adversely affect the aquatic ecosystem when emission directly. This paper use magnesium hydroxide as a wastewater treatment agent, to study the effect of magnesium hydroxide dose, stirring time, temerature on the results of treating fluid treatment, and get the best treatment conditions. The results indicate that magnesium hydroxide has an excellent performance including easy operation, super removing rate, supernatant can meet emission standards: c(Cu2+)≤2mg/L.
Design of a System Coupling Liquid Air Energy Storage System with Thermal Power Unit
Authors: Zhou Zhanfeng
Published: January 2022

In recent decades, the market share of new energy resources is increasing rapidly; the intermittency of new energy resources became an issue to power grids. One prevailing solution is to install large scale energy storage systems. To make energy storage systems participate better in peak shaving without geographical constraints, the paper put forward a new design of a system that couples liquid air energy system with a thermal power unit to utilize waste heat from the condenser of the thermal power unit; the system is also independent from electricity input when producing electricity.
Application of ASAS method to PAMELA calorimeter
Authors: Fedosimova A I , Lebedev I A , Mayorov A G , Dmitriyeva E A , Bondar E A , Krassovitskiy P M , Olimov Kh K , Absalyamova I I , Murzalinov D O
Published: January 2022

In this paper, we propose a method that makes it possible to to improve energy reconstruction for data obtained via thin heterogeneous calorimeters for direct measurements of cosmic rays with energies of TeV and higher. Despite the large number of modern experimental complexes, the primary energy of cosmic nuclei with energies above 1 TeV is determined with large errors associated with fluctuations in the development of the cascade. For heterogeneous calorimeters, transient effects give an additional negative effect. In this paper we analyze the main causes of fluctuations and discuss a method for reducing the effect of fluctuations on the results of primary energy reconstruction. The method of accumulation of signal along the spectrum (ASAS) is used to reduce fluctuations associated with transient effects. The method was tested using the heterogeneous calorimeter of the PAMELA collaboration. It is shown that the proposed approach makes it possible to correctly determine the energy of slowly developing showers, the maxima of which are not measured.
Neutron diffraction study of the Ti1-xMoxC alloy
Authors: Khidirov I , Rakhmanov S J , Parpiev A S
Published: January 2022

In this work, the crystal structure and (RMSD) root-mean-square displacement of atoms in new cubic refractory interstitial alloys Ti0.74Mo0.26C and Ti0.70Mo0.30C were determined by neutron diffraction. These alloys are obtained by powder metallurgy by sintering fine powders of cubic titanium carbides TiC and molybdenum MoC. The values of the RMSD of atoms in these alloys, obtained by the methods of least squares and full-profile analysis from the neutron diffraction data, turned out to be identical. They turned out to be much larger than in the stoichiometric TiC alloy, which has a similar cubic structure and close geometric parameters of atoms with the Ti0.74Mo0.26C and Ti0.70Mo0.30C alloys. These alloys were explained by the occurrence of large static distortions in the lattice of the Ti0.70Mo0.30C alloy due to the differences in the masses and atomic radii of the titanium and molybdenum elements.
Theoretical aspects of direct conversion of radio-chemical energy in electric by radiation-stimulated SiC*/Si heterostructure
Authors: Gurskaya A V , Chepurnov V I , Dolgopolov M V , Puzyrnaya G V , Petenko I A
Published: January 2022

The authors consider their own CVD technology for the SiC growing on a Si substrate in order to create a beta converter. Since the beta converter contains a heavy C-14 atom, the finished beta converter works as an ”inner sun”, and the structure has specific mark * in the name: SiC*/Si. Authors focus on the problems of the theoretical description of: 1) the growth of the SiC*/Si film (with C-14 atoms inside) and the position of the p-n junction in the doping process; 2) method of a placement radioisotopes into a semiconductor material; 3) physical properties of radioisotopes; 4) defects formation; 5) generation of secondary electrons in the region of the p-n junction.
Integration of the differential evolution algorithm and the Monte Carlo code to create a spectrometric detector model
Authors: Prozorova I V
Published: January 2022

A standard procedure for characterizing the high-purity germanium detector (HPGe), manufactured by Canberra Industries Inc [1], is performed directly by the company using patented methods. However, the procedure is usually expensive and must be repeated because the characteristics of the HPGe crystal change over time. In this work, the principles of a technique are developed for use in obtaining and optimizing the detector characteristics based on a cost-effective procedure in a standard research laboratory. The technique requires that the detector geometric parameters are determined with maximum accuracy by the Monte Carlo method [2] in parallel with the optimization based on evolutionary algorithms. The development of this approach facilitates modeling of the HPGe detector as a standardized procedure. The results will be also beneficial in the development of gamma spectrometers and/or their calibrations before routine measurements.
Determination of the content of rare metals in spent anion-exchange resin SIM202 by methods of neutron-activation and mass-spectrometric analysis
Authors: Sadikov I I , Kh Yarmatov B , Usmanov T M
Published: January 2022

The work is devoted to the development of methods for determining the elemental and isotopic composition of spent ion-exchange resin, industrial waste and environmental objects using an inductively coupled plasma mass spectrometer and analyzing specific samples to determine the content of noble and rare metals in technological materials, industrial waste and natural objects with application of the developed techniques. This article determines the elemental composition of the spent ion-exchange resin SIM202 with the Inductively coupled plasma mass spectrometry (ICP-MS) method and also shows the comparison of the results with neutron activation analysis (NAA). The distribution coefficient of elements in a chromatographic column in ion-exchange resins TAO and SIM202 is given.
The current state of uranium legacy sites remediation issues in Uzbekistan
Authors: Kuldjanov BK
Published: January 2022

The uranium production legacy sites in Central Asia are a source of high-level radiological risks for the population and the environment. This fact is recognized by the international community, which is taking measures to remediate the sites. A number of international and national projects have been implemented in the Republic of Uzbekistan, but there is no single source that covers their main results. The article provides a brief overview of the main international initiatives, the results obtained and the lessons learned. The list of necessary measures for the nearest future to recover the environment and ensure normal conditions for the local population is given. The obtained material can be used for planning and implementation remediation of other uranium legacy sites in Central Asia, as well as similar objects around the world.
Technologies for studying functional neural networks of the human brain based on data of nuclear functional magnetic tomography
Authors: Enyagina I M , Poyda A A , Orlov V A , Kozlov S O , Polyakov A N , Ushakov V L , Sharaev M G
Published: January 2022

Nuclear functional magnetic resonance imaging (fMRI) is one of the most popular methods for studying the functional activity of the human brain. In particular, this method is used in medicine to obtain information about the state of the functional networks of the patient’s brain. However, the process of processing and analysis of experimental fMRI data is complex and requires the selection of the correct technique, depending on the specific task. Practice has shown that different processing methods can give slightly different results for the same set of fMRI data. There are a number of alternative specialized software packages for processing and analysis, but the methodology still needs improvement and development. We are working in this direction: we analyze the effectiveness of existing methods; we develop our own methods; we create software services for processing and analysis of fMRI data on the basis of the distributed modular platform “Digital Laboratory”, with the involvement of the supercomputer NRC “Kurchatov Institute”. For research we use experimental fMRI data obtained on the scanner Siemens Verio Magnetom 3T at the Kurchatov Institute. One of our tasks within the framework of this project is to improve the technology for studying large-scale functional areas of the cerebral cortex at rest. To build a hierarchical model of interaction of large-scale neural networks, a verified binding of functional areas to anatomy is required. Today, there are a number of generally accepted atlases of the functional areas of the human cerebral cortex, which, nevertheless, are constantly being finalized and refined. This article presents the results of our study of the Glasser atlas for the consistency of voxels within one region and the connectivity metrics of voxel dynamics.
Multistate Active Combined Power and Message/Data Rate Adaptive Decentralized Congestion Control Mechanisms for Vehicular Ad Hoc Networks
Authors: Deeksha M , Patil Ashish , Kulkarni Muralidhar , V. Shet N. Shekar , Muthuchidambaranathan P.
Published: January 2022

Vehicular ad hoc networks (VANETs) have emerged in time to reduce on-road fatalities and provide efficient information exchange for entertainment-related applications to users in a well-organized manner. VANETs are the most instrumental elements in the Internet of Things (IoT). The objective lies in connecting every vehicle to every other vehicle to improve the user’s quality of life. This aim of continuous connectivity and information exchange leads to the generation of more information in the medium, which could congest the medium to a larger extent. Decentralized congestion control (DCC) techniques are specified to reduce medium congestion and provide various safety applications. This article presents two DCC mechanisms that adapt message rate and data rate combined with transmit power control mechanism. These mechanisms are developed under multi-state active design proposed by the standard. The proposed methods deliver better performance over other mechanisms in terms of power, channel load, and channel utilization using real-time-based scenarios by simulation in SUMO.
Real Time Face Mask Detection using Google Cloud ML and Flutter
Authors: Kummar Sohit , Mohanty Asutosh , Jyotsna  , Chakraborty Sudeshna
Published: January 2022

Coronavirus (Covid-19) pandemic has impacted the whole world and has forced health emergencies internationally. The contact of this pandemic has been fallen over almost all the development sectors. A lot of precautionary measures have been taken to control the Covid-19 spread, where wearing a face mask is an essential precaution. Wearing a face mask correctly has been essential in controlling the Covid-19 transmission. Moreover, this research aims to detect the face mask with fine-grained wearing states: face with the correct mask and face without mask. Our work has two challenging tasks due to two main reasons firstly the presence of augmented data set available in the online market and the training of large datasets. This paper represents a mobile application for face mask detection. The fully automated Machine Learning Cloud service known as Google Cloud ML API is used for training the model in TensorFlow file format. This paper highlights the efficiency of the ML model. Additionally, this paper examines the advancement of the cloud technology used for machine learning over the traditional coding methods.
Performance analysis of texture characterization techniques for lung nodule classification
Authors: Devdatt Kawathekar Ishan , Shaju Areeckal Anu
Published: January 2022

Lung cancer ranks very high on a global index for cancer-related casualties. With early detection of lung cancer, the rate of survival increases to 80-90%. The standard method for diagnosing lung cancer from Computed Tomography (CT) scans is by manual annotation and detection of the cancerous regions, which is a tedious task for radiologists. This paper proposes a machine learning approach for multi-class classification of the lung nodules into solid, semi-solid, and Ground Glass Object texture classes. We employ feature extraction techniques, such as gray-level co-occurrence matrix, Gabor filters, and local binary pattern, and validate the performance on the LNDb dataset. The best performing classifier displays an accuracy of 94% and an F1-score of 0.92. The proposed approach was compared with related work using the same dataset. The results are promising, and the proposed method can be used to diagnose lung cancer accurately.
Design and Implementation of Carbon Nano-tube based Full Adder at 32nm Technology for High Speed and Power Efficient Arithmetic Applications
Authors: Ahmed Khan Imran
Published: January 2022

Due to physical, material, technological, power-thermal and economical difficulties, scaling of CMOS transistors will stop very soon. Due to efficiency of power and speed compared to CMOS transistors, Carbon Nano-tube transistors are best suitable element to design logic circuits. So, CNTFETS have been utilized in designing of proposed full adder (FA) and 4-bit ripple carry adder (RCA) in this paper. Proposed FA and RCA have been compared to rival designs on bases of power, speed and power-delay-product (PDP). FA and RCA circuits have been analysed with the variation of temperature from 0°C to 100°C while the variation of supply voltages is from 0.7V to 1.3V. For all temperatures and all supply voltages, proposed FA and proposed RCA have the least power consumption, shortest delay and lowest PDP. SPICE has been utilized for simulating FAs and RCAs in 32 nm process node. Even though the fabrication is complicated than CMOS counterparts but simulation results confirm usefulness of proposed FA and RCA for high speed and power efficient arithmetic applications.
Machine Learning Approaches in Stock Price Prediction: A Systematic Review
Authors: Soni Payal , Tewari Yogya , Krishnan Deepa
Published: January 2022

Prediction of stock prices is one of the most researched topics and gathers interest from academia and the industry alike. With the emergence of Artificial Intelligence, various algorithms have been employed in order to predict the equity market movement. The combined application of statistics and machine learning algorithms have been designed either for predicting the opening price of the stock the very next day or understanding the long term market in the future. This paper explores the different techniques that are used in the prediction of share prices from traditional machine learning and deep learning methods to neural networks and graph-based approaches. It draws a detailed analysis of the techniques employed in predicting the stock prices as well as explores the challenges entailed along with the future scope of work in the domain.
Measurement of ionization loss of 50 GeV protons in silicon with smoothly tunable up to 1 cm thickness using a single flat detector
Authors: Nazhmudinov R.M. , Shchagin A.V. , Kubankin A.S. , Afonin A.G. , Britvich G.I. , Durum A.A. , Kostin M.Y. , Maisheev V.A. , Pitalev V.I. , Chesnokov Y.A. , Yanovich A.A.
Published: January 2022

Research of the ionization loss of 50 GeV protons, the path of which in the depleted layer of the silicon detector was smoothly regulated in the range from 0.3 to 10 mm, is presented. In the experiment, we used a flat silicon detector with a fixed thickness of the depleted layer of 300 μm. The smooth regulation of the path was realized due to the variation of the angle between the surface of the detector and the incident proton beam. The comparison of experimental data and theoretical calculations of the ionization loss demonstrates agreement in all range of thicknesses. Results of the research can be used in order to control the angle between the surface of the detector and the incident beam of relativistic particles. Besides, the results can be used in the analysis of data from astrophysical silicon detectors of charged particles if high-energy particles crossed flat detectors at arbitrary angle.
Stronger Arctic amplification from ozone-depleting substances than from carbon dioxide
Authors: Liang Yu-Chiao , Polvani Lorenzo M , Previdi Michael , Smith Karen L , England Mark R , Chiodo Gabriel
Published: January 2022

Arctic amplification (AA)—the greater warming of the Arctic near-surface temperature relative to its global mean value—is a prominent feature of the climate response to increasing greenhouse gases. Recent work has revealed the importance of ozone-depleting substances (ODS) in contributing to Arctic warming and sea-ice loss. Here, using ensembles of climate model integrations, we expand on that work and directly contrast Arctic warming from ODS to that from carbon dioxide (CO2), over the 1955–2005 period when ODS loading peaked. We find that the Arctic warming and sea-ice loss from ODS are slightly more than half (52%–59%) those from CO2. We further show that the strength of AA for ODS is 1.44 times larger than that for CO2, and that this mainly stems from more positive Planck, albedo, lapse-rate, and cloud feedbacks. Our results suggest that AA would be considerably stronger than presently observed had the Montreal Protocol not been signed.
Wear behavior of hydroxyapatite reinforced polymer composite for biomedical applications
Authors: Srinivasan D , Balasundaram R , Ravichandran M , Sakthi balan G , Vijay S , Vishnu S
Published: January 2022

In medical fields, hydroxyapatite (HA) is used for restoring the human bones and teeth. Nowadays, newer bio composites are being developed to replace the broken or removed teeth in human using hydroxyapatite. The original teeth may be removed from human, due to various reasons such as tooth decay, periodontal disease and gum diseases. Due to the bioactivity property of HA, it helps the tooth to grow. In this work, tribological properties of HA powder reinforced composite are investigated. Three most important factors that affect the properties of the composites were chosen and varied during wear testing of the composites. The HA powder weight %, applied load (P) and sliding distance (SD) were varied on the basis of Taguchi’s experimental design. Analysis of variance (ANOVA) and (Signal to Noise) SN ratio analysis was used to study the influence of each factor on the specific wear rate (SWR). It was concluded that the HA wt% highly influences the SWR of the composite during pin on disc testing.
Improving element uniformity and mechanical properties of Al–Mg–Si alloy fabricated by twin roll casting with superheat melt treatment
Authors: Wei Bowen , Jiang Tao , Li Shiju , Zhang Youyun , Xu Guangming , Li Yong , Wang Zhaodong
Published: January 2022

The effect of superheat melt treatment(SMT) on microstructure and properties of Al–Mg–Si alloy fabricated by twin roll casting(TRC) was analyzed using optical microscope, scanning electron microscopy, emission electron probe micro analyzer and transmission electron microscopy. SMT increased the subcooling degree of melt during TRC. The solidification microstructure with high dendrite density and small dendrite spacing was obtained. The second phase was evenly distributed between dendrites and the solute concentration gradient was decreased. Intergranular solute aggregation caused by Reynolds’ dilatancy in TRC slab was effectively suppressed. The homogeneous solute distribution of TRC slab with SMT can be realized by short-time homogenization heat treatment. The size of insoluble particles was greatly reduced. The complete decomposition of non-equilibrium eutectic phase increased the solute concentration in α-Al, which promoted the precipitation of precipitates during aging heat treatment. The tensile strength and yield strength of T6 slab were improved, while the uniform elongation are almost not decreased. The strength and uniform of slab in T4P state were both improved. The obtained results can help further shorten the production cycle of TRC slabs and improve mechanical properties.
An electromagnetic wave attenuation superposition structure for thin-layer plasma
Authors: ZHANG Wenyuan , XU Haojun , PEI Binbin , WEI Xiaolong , FENG Pei , ZHANG Lin
Published: January 2022

This work proposes a new plasma super-phase gradient metasurfaces (PS-PGMs) structure, owing to the limitations of the thin-layer plasma for electromagnetic wave attenuation. Based on the cross-shaped surface unit configuration, we have designed the X-band absorbing structure through the dispersion control method. By setting up the Drude dispersion model in the computer simulation technology, the designed phase gradient metasurfaces structure is superposed over the plasma, and the PS-PGMs structure is constructed. The electromagnetic scattering characteristics of the new structure have been simulated, and the reflectance measurement has been carried out to verify the absorbing effect. The results demonstrate that the attenuation effect of the new structure is superior to that of the pure plasma structure, which invokes an improved attenuation effect from the thin layer plasma, thus enhancing the feasibility of applying the plasma stealth technology to the local stealth of the strong scattering part of a combat aircraft.