bluuebunny/crossref_metadata_2025_split huggingface dataset:
Device physics of homojunction perovskite solar cells: a design omitting all the charge transport layers with efficiency exceeding 26.3%
Authors: Da Yun , Xie Meiqiu 
Published: March 2022

Abstract
Perovskite solar cells (PSCs) omitting all the charge transport layers with p–n homojunction structure are considered a promising alternative for commercialization owing to their low fabrication cost and simplified structure. Deep understanding of the device physics of these all-free p–n homojunction structured PSCs is of paramount importance. Here, a thorough investigation of all-free perovskite–perovskite p–n homojunction structured PSCs is performed by using a photoelectrical coupling model. Four different configurations including a standard n–i–p cell, electron transport layer-free cell, hole transport layer-free cell, and all-free cell are compared to identify the limiting performance factors, and the results indicate that no extra built-in electric field in the perovskite layer and severe surface recombination occurring at the perovskite interface are the two main factors limiting the power conversion efficiency (PCE) of all-free p–n homojunction structured PSCs. Based on doping engineering, a highly efficient all-free p–n homojunction structure is designed, which consists of an asymmetric p–n junction with both a front surface field layer and a back surface field layer. The effects of optical loss, thickness of the emitter, doping concentration for both the emitter and base, and diffusion length on the performance of p–n homojunction structured PSCs are optimized. After optimization, the PCE of the all-free p–n homojunction structured PSCs reaches 26.33%, which is slightly higher than that of a standard n–i–p heterojunction cell (26.22%). This work demonstrates that all-free p–n homojunction structured PSCs are a promising alternative to standard n–i–p heterojunction structured PSCs for realizing high efficiency, which may pave the way toward commercialization of PSCs in the future.
Dosimetry in targeted alpha therapy. A systematic review: current findings and what is needed
Authors: Tronchin Stephen , Forster Jake C , Hickson Kevin , Bezak Eva 
Published: March 2022

Abstract

Objective. A systematic review of dosimetry in Targeted Alpha Therapy (TAT) has been performed, identifying the common issues. Approach. The systematic review was performed in accordance with the PRISMA guidelines, and the literature was searched using the Scopus and PubMed databases. Main results. From the systematic review, three key points should be considered when performing dosimetry in TAT. (1) Biodistribution/Biokinetics: the accuracy of the biodistribution data is a limit to accurate dosimetry in TAT. The biodistribution of alpha-emitting radionuclides throughout the body is difficult to image directly, with surrogate radionuclide imaging, blood/faecal sampling, and animal studies able to provide information. (2) Daughter radionuclides: the decay energy of the alpha-emissions is sufficient to break the bond to the targeting vector, resulting in a release of free daughter radionuclides in the body. Accounting for daughter radionuclide migration is essential. (3) Small-scale dosimetry and microdosimetry: due to the short path length and heterogeneous distribution of alpha-emitters at the target site, small-scale/microdosimetry are important to account for the non-uniform dose distribution in a target region, organ or cell and for assessing the biological effect of alpha-particle radiation. Significance. TAT is a form of cancer treatment capable of delivering a highly localised dose to the tumour environment while sparing the surrounding healthy tissue. Dosimetry is an important part of treatment planning and follow up. Being able to accurately predict the radiation dose to the target region and healthy organs could guide the optimal prescribed activity. Detailed dosimetry models accounting for the three points mentioned above will help give confidence in and guide the clinical application of alpha-emitting radionuclides in targeted cancer therapy.
Suppression of fast neutrino flavor conversions occurring at large distances in core-collapse supernovae
Authors: Abbar Sajad , Capozzi Francesco 
Published: March 2022

Abstract
Neutrinos propagating in dense neutrino media
such as core-collapse supernovae
and neutron star merger remnants
can experience the so-called fast flavor
conversions on scales
much shorter than those expected in vacuum. A very generic class of fast flavor instabilities is the ones which are produced by the backward scattering
of neutrinos off the nuclei at relatively large distances from the supernova core.
In this study we demonstrate that despite their ubiquity, such fast instabilities are unlikely
to cause significant flavor conversions
if the population of neutrinos in the backward direction is not large enough.
Indeed, the scattering-induced instabilities can mostly impact the
neutrinos traveling in the backward direction, which represent only a small fraction of neutrinos at large radii.
We show that this can be explained by the shape
of the unstable flavor eigenstates, which can be extremely peaked at the backward angles.
Electromagnetic form factors of neutron and neutral hyperons in the oscillating point of view *
Authors: Dai An-Xin , Li Zhong-Yi , Chang Lei , Xie Ju-Jun 
Published: March 2022

Abstract
Based on the recent precise measurements by the BESIII collaboration for electron–positron annihilation into a neutron and antineutron pair, the effective form factors of the neutron were determined in the time-like region, and it was found that the effective form factors of the neutron are smaller than those of the proton. The effective form factors of the neutron show a periodic behaviour, similar to those of the proton. Here, a comparative analysis for Λ,

and

hyperons is performed. Fits of the available data on the effective form factors of Λ,

and

with zero charge show an interesting phenomenon in the oscillating behavior of their effective form factors. However, this will need to be confirmed by future precise experiments. Both theoretical and experimental investigations of this phenomenon can shed light on the reaction mechanisms of the electron–positron annihilation processes.
The Evolution of the Nucleus Surface in the Context of the Change in the Brightness of a Comet*
Authors: Wesołowski Marcin 
Published: March 2022

Abstract
The paper presents a model of the thermodynamic evolution of the comet nucleus surface. In the proposed approach, we focus on the analysis of the formation of pits visible on the surface of the cometary nucleus. These pits are a consequence of the thermodynamic evolution of both the surface layers and the inner layers of the cometary nucleus. As a result of complex thermodynamic processes, the surface layer is destroyed. A measure of this destruction is the amount of comet material that is thrown into a coma as a result of sublimation. The effect of this process is an increase in the area on which the incident light scatters. Then we can notice a sudden increase in the brightness of the comet, i.e., its outburst. A measure of the amplitude of a given outburst is the diameter and thickness of the surface layer that has been destroyed. The mechanism of the evolution of the pits was proposed based on the analysis of many photos taken by the Rosetta probe. The obtained numerical values correspond to the actual brightness changes of the Jupiter family comets during their outburst.
Comparison the effectiveness two methods: of the spanning trees sampling method and method Rand-ESU
Authors: Gam A V 
Published: March 2022

Abstract
Calculation of the cutoff probability in the Rand-ESU method. Identification of weak points of the method through the random sampling of spanning trees, also the Rand-ESU method with has implemented in the igraph library. Implemented in library igraph. Comparison of methods for counting subgraphs at four vertices. Prospects for the development of the spanning tree sampling method.
Mechanical Properties Degradation Modeling of Austenitic Chromium-Nickel AISI 304 Steel After Thermal Ageing
Authors: Margolin B Z , Petrov S N , Prokoshev O Yu , Kondrateva A M 
Published: March 2022

Abstract
Austenitic chromium-nickel steel AISI 304 is used as a structural material for heat exchange equipment. Long-term operations result in degradation of mechanical properties of material due to formation of chromium carbides at grain boundaries. The influence of various thermal ageing modes of AISI 304 steel on mechanical properties with metal fragments of reactor plant on fast neutrons of RP BN-600 taken as an example after long-term operation has been investigated.
Building and training a fuzzy neural model of data mining tasks
Authors: Muhamediyeva D T 
Published: March 2022

Abstract
In this paper discussed the problem of constructing and training a fuzzy neural network based on fuzzy logical rules. Based on the constructed model, the developed algorithm, the objects classified with indistinct initial information. Under these conditions, traditional methods of mathematical statistics or simulation modeling do not allow building adequate models for solving data mining problems. We consider the solution of problems based on the use of intelligent modeling technologies using methods of neural networks and fuzzy logic in order to automate the construction of fuzzy rules based on methods and algorithms of machine learning.
Application of data mining methods in solving medical problems
Authors: Muhamediyeva D K , Ruzibaev O B , Baxromova Yu 
Published: March 2022

Abstract
Mathematical methods in medicine - the criteria for determining the status of research objects related to medicine and health problems, methods and algorithms for assessing, analyzing and forming a set of quantitative variables are analyzed. Because of the analysis, problems and tasks were identified that need to be addressed.
Flow management in optimal resource exchange tasks
Authors: Nartov B K , Poluyanov A N 
Published: March 2022

Abstract
The paper presents a method for optimal initial allocation of resources of a dynamical system and reallocation of resources at the control interval. The main types of practical tasks on the exchange of material, energy and information resources are considered. A general scheme is given for their formalization using a special extension of the dynamical system of the original problem. The results of verification simulation experiments are presented.
Application of neural network language models based on distributive semantics for ontological modeling of the domain
Authors: Shishaev M G , Dikovitsky V V , Pimeshkov V K 
Published: March 2022

Abstract
The article discusses the technology of automated formation of SKOS-ontologies for semantic modeling of the subject area, based on natural language texts analysis. The technology is based on neural network and distributive (vector) language models. A brief description of the content and formulation of the problem of extracting concepts and relations from natural language texts is given, the results of constructing a neural network classifier of SKOS relations using the Glove vector model, as well as an example of using the technology to construct a fragment of an applied SKOS ontology are given.
Numerical simulation of heat-transfer fluid warm-up in heating facilities with heat transfer augmentation achieved with swirling flow
Authors: Zakharov Y N , Stukolov S V 
Published: March 2022

Abstract
Swirling flow of heat transfer fluid in heating facilities is a compelling way to intensify heat transfer augmentation. The paper considers the process of passive swirling flow in heating pipes by way of application of special design pipe connectors. Numerical simulation has been accomplished on the basis of viscous incompressible fluid model represented by Navier-Stokes equations complemented with temperature transfer equation. Numerical experiments has been completed with the help of applied software OpenFOAM based on finite volume method.
The analysis of the deposits formation on the working surfaces of heat exchange industrial equipment
Authors: Batrakov P A , Lasitsa A M , Peshko M S , Averchenko A P 
Published: March 2022

Abstract
The article considers the processes of deposits formation on the walls of heat exchangers. Experimental studies of the composition and structure of deposits in heat exchange equipment elements are carried out. The regularities of deposition are studied. The possibility of virtualization of deposits monitoring sensors is analyzed. The conclusion is made about the possibility of analytical prediction of the behavior of heat exchange equipment during the deposition and their influence on the heat transfer process. A partial replacement of experimental physical and chemical studies by simulation is proposed.
On Investigation of Crisp Bi-Objective Formulations for Fuzzy Traveling Salesman Problem and Fuzzy p-Median Problem
Authors: Zakharov Aleksey O. , Zakharova Yulia V. 
Published: March 2022

Abstract
We consider two classic problems: the Traveling Salesman Problem and the p-Median Problem. In both problems the total traveling cost (in some sense) is minimized, assuming that all traveling times are known. In most real-word applications the input data are uncertain, and this fact should be taken into account when a solution is constructed. In this paper we investigate bi-objective versions of the problems, where the total cost and fuzzy uncertainty associated with the traveling times (membership function) are optimized. A greedy approximation algorithm is proposed and experimentally tested on instances from TSPLIB library.
Improving the quality of modeling thermodynamic processes
Authors: Brazhnikova K 
Published: March 2022

Abstract
On the example of modeling thermodynamic processes occurring in the on-board gasification system (OGS) of unprocessed liquid fuel residues in the tanks of the launch vehicle stage (LV), using a reduced physical model of the fuel tank – an experimental model installation (EMI) as part of an experimental stand (ES), the design parameters of which are determined (geometric parameters, coolant and characteristics of the model fluid) based on the theory of similarity of thermophysical processes occurring in the real design of the fuel tank of the LV stage according to the criteria of Reynolds, Nusselt, Prandtl, methodological recommendations are proposed to improve the quality of the process of theoretical and experimental research at the stage of scientific research (R&D).
Friction stir processing as a method of hardening cutting tools
Authors: Chernykh I K , Vasil’ev E V , Badamshin A M , Kushnareva A G 
Published: March 2022

Abstract
One of the most perspective methods of hardening is friction stir processing. The study shows processing methods based on the friction stir principle. The results of hardening of tool steels 1089 (Fe97%, C0.8%), 3343 (Fe80%, C0.9%, Cr4%, Mo5%, W6%, V2%), 440C (Fe78%, Cr18%, C0.95%) are presented. As a result of hardening, it was possible to increase the microhardness of carbon tool steel by more than 3 times, and also to achieve a decrease in the average grain size in the treated area by more than 10 times in relation to the base material. It is proposed to use the FSP in the manufacture of cutting tools from tool steels to increase physical and mechanical properties.
Improving the quality and efficiency of friction stir welding of aluminum alloy plates
Authors: Chernykh I K , Vasil’ev E V , Kushnareva A G , Krivonos E V 
Published: March 2022

Abstract
Friction stir welding (FSW) is best suited for welding large-sized aluminum alloy parts. Finding optimal welding conditions and methods for minimizing defects arising during welding is an urgent task, the solution of which is necessary for the commissioning of FSW technology into the industry. The introduction of this method for welding rocket fuel tanks will increase the productivity of manufacturing products and their strength. The aim of this study is to improve the quality of friction stir welding of 7,6 mm thick Al-Mg6% aluminum alloys, as well as to increase productivity. The aim is achieved by finding optimal welding conditions and modernizing the welding method for simultaneous stripping by milling. The optimal welding modes found as a result of the study allow ensuring the strength of the welded joint, reaching 98% of the strength of the base material. The modernized welding method allows milling (deburring) to be carried out simultaneously with welding, which can significantly reduce the manufacturing time of the product, for which deburring is a necessary operation. As a result of the study, the welding modes were also revealed, leading to the appearance of hidden defects, which can reduce the strength of the welded joint by 2 times. A conditional diagram showing the appearance of defects in various combinations of modes has been compiled.
Fire detection system call points types selection based on the gas and smoke environment physical parameters dynamic study in different premises
Authors: Khrapskii S F , Bedrina E A 
Published: March 2022

Abstract
Fire detection system call points types selection is determined by the gas-smoke environment prevailing physical parameter in fire case and by this parameter change dynamic as combustion develops. Obtaining of practically important information about the gas-smoke environment prevailing parameters during a fire, their changes dynamic and the time when they reach the threshold values for call points for real objects is possible on the numerical studies results basis using the FDS program complex modeling heat and mass transfer and gas dynamic processes occurring during a fire. The performed calculations made it possible to obtain the temperature dependences, smoke optical density and carbon monoxide concentration in the near-ceiling area on time since the ignition start for a number of characteristic rooms for various purposes. The call points type choosing ambiguity for rooms with different fire load indicators is shown. The calculated data can serve as a basis for choosing the fire detection system call points types, as well as for setting up and effective functioning of multi-sensor and multi-criteria fire detectors.
Non-Linear Oscillations of the Channel Wall Filled with a Viscous Liquid Induced by the Vibrating Foundation
Authors: Popov V S , Popova A A , Christoforova A V 
Published: March 2022

Abstract
The paper considers the issues of mathematical modelling nonlinear vibrations for the wall of a narrow parallel walled channel filled with a viscous incompressible liquid. The upper channel wall is a rigid rectangular plate supported by nonlinear spring with a cubic restoring force, while the bottom one is a fixed rigid rectangular plate. The case of nonlinear oscillations of the upper channel wall due to channel’s foundation vibration has been investigated in the frame of hydroelasticity problem. The main attention is paid to the consideration of steady-state nonlinear oscillations for the upper channel wall and the creeping motion of the liquid in the channel. The liquid layer reaction acting on the upper channel wall is found and the channel’s wall nonlinear oscillation equation is obtained taking into account the energy dissipation due to the liquid viscosity. It was shown that this equation coincided with the Duffing one. The solution of the nonlinear oscillation equation was carried out by the harmonic balance method. Based on the found solution, the hydroelastic response of the channel wall on a nonlinear elastic suspension to the channel foundation vibration was determined.
Efficiency of the use of feedback in the stabilization of motion of the rotary hydraulic drive
Authors: Syrkin V V , Galuza Yu F , Kvasov I N , Abramova I A 
Published: March 2022

Abstract
This article reflects a study of the operation of a hydraulic drive with nonlinear characteristics of an axial piston hydraulic motor, which operates at the lower limit of the speeds of the executive bodies. A nonlinear frictional moment arises in the end valve of the hydraulic motor connected to the actuator and leads to movement with stops. The mathematical models of the dynamics of the hydraulic drive, proposed in this study, are linearized by the method of harmonic linearization and allow engineering calculations of the parameters of the modes of non-stop motion. Evaluation of the dynamic properties of the hydraulic drive, corresponding to the onset of an unstable mode, makes it possible to determine the minimum value of the constant component of the speed of the executive body.
Modeling and Analysis of Delta Kinematics FDM Printer
Authors: Zakharov O V , Pugin K G , Ivanova T N 
Published: March 2022

Abstract
Additive manufacturing makes it possible to speed up the process of manufacturing a product using a CAD model many times over. This advantage is effectively used in the manufacture of small batches of products with complex surfaces in the automotive and aviation industries. Improvements in printers are needed to improve accuracy and productivity. Traditionally, delta kinematics are considered to have advantages over sequential linear kinematics due to their high travel speed and relatively low cost. However, delta kinematics has received limited application, mainly for personal FDM printers. The article attempts to understand the advantages and disadvantages of delta kinematics for use in 3D printers. For this, the displacements and velocities were simulated for four examples of motion trajectories. The analysis showed that the average speed of movement of the extruder is approximately equal to, and in some cases less than the linear speeds of movements along the rods. At the same time, to ensure a uniform speed of the extruder, significant accelerations are required along the individual rods. This leads to vibrations and ultimately limits the maximum speeds.
Investigation of a Mechanism of Structural Transformations in High-Strength Steel
Authors: Fedoseev M L , Petrov S N , Mikhaylov M S , Islamov A Kh , Ryabov V V 
Published: March 2022

Abstract
Mechanical, technological and operational properties of metal materials are largely influenced by changes of concentrations, morphology, dimensions, localization, elemental and phase composition of dispersed precipitates. This paper is devoted to a study of dispersed carbides of submicron size at tempering of high-strength medium-carbon steel. The main emphasis is on comparing the data obtained by small-angle neutron scattering and transmission electron microscopy. As a result of the analysis, it was found that carbide growth begins in the investigated steel immediately after quenching when the tempering temperature increases. First, it is fixed by a transmission electron microscopy and a small-angle neutron scattering and then above ~ 300 ° C carbide growth is fixed by neutron diffraction. The residual austenite is also completely dissolved by the time the temperature reaches ~ 300 °C. A good matching has been reached for the methods used. It has been shown that a complex use of integral and local methods allows to obtain fully information about the structure and properties of the investigated material.
Investigation of Ti/TiB2Composite Wear Resistance and Corrosion Resistance Coatings in Aggressive Medium and at Variable Temperatures
Authors: Goshkoderya M E , Bobkova T I , Belyakov A N , Yakovleva N V 
Published: March 2022

AbstractThe present work investigates the influence of conditions like the climate of the Arctic shelf, such as aggressive medium, hydroabrasive wear and variable temperatures on Ti/TiB2composite coatings. The applicable composite powders were investigated with the use of thermogravimetric analysis. The values of corrosion resistance and wear resistance of the coatings were also investigated.