bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence factors of resolution in laser accelerated proton radiography and image deblurring
Authors: Li D. Y. , Xu X. H. , Yang T. , Wu M. J. , Zhang Y. F. , Cheng H. , Hu X. Y. , Geng Y. X. , Zhu J. G. , Zhao Y. Y. , Zhu K. , Ma W. J. , Lin C. , Yan X. Q.
Published: August 2021

Contact imaging based on MeV energy laser accelerated protons is studied in this paper. First, we show that both external structures and the internal organs of ants can be distinguished with micrometer spatial resolution by proton radiography. Then, we systematically study several specific influence factors and their coupled effects on the spatial resolution of proton radiography, i.e., the accumulated shot number, the proton irradiation dose, the different types of detectors, and the incident proton energy, using two specially designed resolution calibration targets. Under our experimental conditions with MeV protons, the best resolution obtained with the radiochromic film is 20 μm, and that with the solid-state nuclear-track detector (CR39) is 10 μm. In the end, we propose an image deblurring algorithm that uses deconvolution to eliminate the blurring caused by the nonzero spatial extent of the source and multiple Coulomb scattering. This work studies the comprehensive factors of laser accelerated proton radiography with resolution calibration targets and presents incremental additions to previous work on proton radiography.
Spectral characterization of flash and high flux x-ray radiographic sources with a magnetic Compton spectrometer
Authors: Espy M. , Klasky M. , James M. , Moir D. , Mendez J. , Morneau R. , Shurter R. , Sedillo R. , Volegov P. , Gehring A.
Published: August 2021

In this work, we present a new analysis method applied to revitalize permanent magnet Compton spectrometers used to measure photon energy spectra in the MeV range. The inversion of the measured electron distribution to determine the original photon distribution is achieved via a method of consistent coupled radiation transport and magnetic field mapping of the input photon spectra to the measured electron distribution. The method of linear least squares was used to perform the unfolding of the electron distribution to the initial photon spectra, without any assumptions made regarding the electron distribution. We present an application of this method to data from a nominal 19.4 MeV flash radiographic source (the first axis of the Dual Axis Radiographic Hydro-Test Facility) capable of generating 500 R @ 1 m in ∼60 ns and a medical therapy source (a Scanditronix M22, Microtron) capable of variable energies with nominal endpoints of 6, 10, 15, and 20 MeV and an output of ∼1000–2000 R/min @ 1 m. The results provide agreement between the modeled and unfolded experimentally measured photon spectra as quantified by statistical tests, from 1.5 to 20 MeV. Experimental results are presented as well as a discussion of the novel MCNP6-based simulations and methods for reconstruction of the spectra.
Inertial Lévy flights in bounded domains
Authors: Capała Karol , Dybiec Bartłomiej
Published: August 2021

The escape from a given domain is one of the fundamental problems in statistical physics and the theory of stochastic processes. Here, we explore properties of the escape of an inertial particle driven by Lévy noise from a bounded domain, restricted by two absorbing boundaries. The presence of two absorbing boundaries assures that the escape process can be characterized by the finite mean first passage time. The detailed analysis of escape kinetics shows that properties of the mean first passage time for the integrated Ornstein–Uhlenbeck process driven by Lévy noise are closely related to properties of the integrated Lévy motions, which, in turn, are close to properties of the integrated Wiener process. The extensive studies of the mean first passage time were complemented by examination of the escape velocity and energy along with their sensitivity to initial conditions.
3D models of the dynamics of cancer cells under external pressure
Authors: Semenova Nadezhda , Tuchin Valery V.
Published: August 2021

Skin cancer is one of the most frequent cancers worldwide. Recently, it has been shown that the tumor proliferation rate in skin and its dynamics can be changed by an osmotic pressure. However, these findings are rather unstructured. A weak pressure can slow down the tumor growth, while a very high pressure can, on the contrary, lead to accelerated growth and metastases. The magnitude and spatial distribution of osmotic pressures in tumors at present cannot be measured experimentally. Therefore, it is of particular interest to find appropriate models that would simulate the effects of additional osmotic pressures in skin and assess the features of its implementation. In this paper, we suggest an improved model based on the principles of the conventional hydrodynamic model for macrophase separations, which allows one to include not only the properties of healthy and cancer cells but also the microenvironment. We study and analyze the proliferation of cancer cells in 3D models of the epidermal layer of skin under an osmotic pressure. There are two suggested 3D models that are based on the same principles: (1) cellular cubic lattice and (2) cell spheroid. This allows expanding the application of the model depending on a given task. Here, we are focused on the study of melanoma at an early stage when there are not many cancer cells. Additional compressive and expansive pressures are added to the central part of the system. Both systems demonstrate similar results in slowing down the rate of tumor growth with a small pressure.
Modeling of stress wave propagation in matrix cracked laminates
Authors: Kanu Nand Jee
Published: August 2021

The conventional finite element method can be used for modeling the multiscale phenomenon of the interaction of Lamb waves with matrix cracks, but it requires a lot of computational resources. In the present investigation, appropriate damage models are used to model the reduction in the stiffness of the ply in which the matrix crack has occurred. Moreover, the interactions of Lamb waves with matrix cracks, which have been modeled as a local reduction in stiffness, are being studied. Furthermore, in a Glass Fiber Reinforced Plastic (GFRP) laminate with a [0/90/90/0] lay-up, Lamb waves of various frequencies and with So (symmetric) and Ao (asymmetric) modes are transmitted along the fiber and across the fiber directions, respectively. As a result, such waves are recorded at two points, 75 and 225 mm from the site of excitation. For two different crack densities, such as 1 crack/mm and 4 cracks/mm, the healthy and damaged laminate signals of similar mode are compared. The amplitudes of the received signals are reduced upon interaction of these waves with damage (with degraded stiffness values), indicating that So modes of Lamb waves are much more susceptible to damages at higher frequencies of 100, 150, and 200 kHz compared to Ao modes. Furthermore, for a given crack density, equivalent damage models are validated by comparing these signals to cracked laminate signals of similar frequencies and modes. During the study, it was revealed that equivalent damage models are perfectly appropriate for modeling matrix cracks of any density as a local loss in stiffness in the damaged crossply GFRP laminate.
Monte Carlo modeling of spin-polarized photoemission from p-doped bulk GaAs
Authors: Chubenko Oksana , Karkare Siddharth , Dimitrov Dimitre A. , Bae Jai Kwan , Cultrera Luca , Bazarov Ivan , Afanasev Andrei
Published: August 2021

The anticorrelation between quantum efficiency (QE) and electron spin polarization (ESP) from a p-doped GaAs activated to negative electron affinity is studied in detail using an ensemble Monte Carlo approach. The photoabsorption, momentum and spin relaxation during transport, and tunneling of electrons through the surface potential barrier are modeled to identify fundamental mechanisms, which limit the efficiency of GaAs spin-polarized electron sources. In particular, we study the response of QE and ESP to various parameters, such as the photoexcitation energy, doping density, and electron affinity level. Our modeling results for various transport and emission characteristics are in good agreement with available experimental data. Our findings show that the behavior of both QE and ESP at room temperature can be fully explained by the bulk relaxation mechanisms and the time that electrons spend in the material before being emitted.
Characterisation of sperm production and morphology in the male Philippine crocodile
Authors: Sandmaier Shelley E. S. , Shepard Teresa , Reeves Andy , Bohr Kaytlin , Krebs Jessi , Herrick Jason R.
Published: August 2021

Philippine crocodiles Crocodylus mindorensis are critically endangered due to agricultural and fishing threats that have severely fragmented their habitat and population in the Philippines. Captive management plans are important to safeguard against their extinction, but the current population in US zoos is small, and breeding is hampered by the slow growth of this species and the danger of introducing differently sized animals for breeding. There is little information regarding the sperm characteristics of crocodilians, and none for Philippine crocodiles. In this study, we sought to characterise sperm production in the male Philippine crocodile (n = 1) by performing voluntary (without sedation or restraint) collections (n = 181) over a 3.5-year period. Peak sperm production in this individual occurs from January to July, when the mean (±s.e.m.) total number of spermatozoa recovered was 10.2 × 106 ± 3.8 × 106 (n = 104), compared with 0.3 × 106 ± 0.2 × 106 (n = 71) for all other months of the year. Analysis of sperm morphology indicated that 15.9% of spermatozoa exhibited normal morphology. A bent tail was the most common abnormality (48.2%) observed. Understanding the basic reproductive biology of the male Philippine crocodile will facilitate the development of artificial reproductive technologies to improve captive propagation and genetic management of this species.
Bureaucratic inertia in dealing with annual forest fires in Indonesia
Authors: Purnomo Eko Priyo , Ramdani Rijal , Agustiyara  , Nurmandi Achmad , Trisnawati Dina Wahyu , Fathani Aqil Teguh
Published: August 2021

Indonesia has sustained annual forest fires since the 1990s related to land clearing activities for agriculture. The Indonesian Government has made substantial efforts to resolve annual fires by improving intergovernmental coordination at national and local levels. Overall, 96 government agencies are liable for controlling forest fire. This study explores local to central government’s bureaucratic reluctance in addressing forest fires, focusing on Riau Province, the most forest fire-prone region in Indonesia. Data were collected from 2015 to 2019 using participatory observation, engaging in meetings of key players; in-depth interviews with key heads of relevant agencies, officials, and NGOs; and a questionnaire for Social Network Analysis. The results show that there are seven influential institutions for addressing land and forest fires in Riau. However, the power of the decision-making process is concentrated at the level of the President and the Governor as the regional leader, which implies that large institutions involved in fire response have less power and responsibility owing in part to bureaucratic inertia as bureaucracy is overly centralised and less responsive. In the long term, devolution of government authority from the central to the local level is required to furnish front-line institutions with the power to deal with the fires.
Comparative analysis of the coordinated motion of Hsp70s from different organelles observed by single-molecule three-color FRET
Authors: Voith von Voithenberg Lena , Barth Anders , Trauschke Vanessa , Demarco Benjamin , Tyagi Swati , Koehler Christine , Lemke Edward A. , Lamb Don C.
Published: August 2021

Significance

The coordinated motion and conformational changes are fundamental for the function of many macromolecules. However, obtaining direct evidence of coordinated changes between different subdomains within an individual molecule remains challenging. Here, we apply a single-molecule three-color Förster resonance energy transfer to simultaneously measure three distances within a single molecule. We utilized this method to analyze the coordinated motion of heat-shock proteins (Hsps). Excitingly, our study provides direct evidence for key differences in the conformational cycle of different Hsp70s despite their high evolutionary conservation. This work paves the way to relate coordinated motion and allosteric effects to molecular function.
RyR-mediated Ca2+release elicited by neuronal activity induces nuclear Ca2+signals, CREB phosphorylation, and Npas4/RyR2 expression
Authors: Lobos Pedro , Córdova Alex , Vega-Vásquez Ignacio , Ramírez Omar A. , Adasme Tatiana , Toledo Jorge , Cerda Mauricio , Härtel Steffen , Paula-Lima Andrea , Hidalgo Cecilia
Published: August 2021

Significance

The expression of genes involved in hippocampal synaptic plasticity, learning, and memory requires that Ca2+signals generated in spines, dendrites, or the soma by neuronal stimulation reach the nucleus. Here, we report that stimulation of hippocampal neurons induces Ca2+release mediated by RyR2 channels, which contributes to nuclear Ca2+signal generation. Suppression of RyR-mediated Ca2+release inhibited the activity-induced phosphorylation of the nuclear transcriptional regulator CREB and the expression of the Npas4 transcription factor and RyR2, which play crucial roles in hippocampal memory processes. We propose that RyR-mediated Ca2+release induced by neuronal stimulation, by promoting the sequential generation of nuclear Ca2+signals, CREB phosphorylation, and Npas4/RyR2 up-regulation, plays a significant role in hippocampal synaptic plasticity and spatial memory processes.
Astrocyte-derived neurons provide excitatory input to the adult striatal circuitry
Authors: Dorst Matthijs C. , Díaz-Moreno María , Dias David O. , Guimarães Eduardo L. , Holl Daniel , Kalkitsas Jannis , Silberberg Gilad , Göritz Christian
Published: August 2021

Significance

The adult mammalian brain has a poor regenerative capacity. Astrocytes have the potential to enter a neurogenic program, which could supply new neurons to the adult brain. In the adult striatum, reduced Notch signaling in astrocytes leads to the generation of neurons. However, it has been unclear whether striatal astrocyte-derived neurons become integrated and which neuronal properties they possess. Here, we show that induced adult neurogenesis by striatal astrocytes leads to the generation of glutamatergic neurons that functionally integrate into the adult striatal circuitry. The integration of glutamatergic neurons provides a local source of excitation to the striatum that could potentially compensate for reduced excitatory input due to aging or disease.
A polyyne toxin produced by an antagonistic bacterium blinds and lyses a Chlamydomonad alga
Authors: Hotter Vivien , Zopf David , Kim Hak Joong , Silge Anja , Schmitt Michael , Aiyar Prasad , Fleck Johanna , Matthäus Christian , Hniopek Julian , Yan Qing , Loper Joyce , Sasso Severin , Hertweck Christian , Popp Jürgen , Mittag Maria
Published: August 2021

Significance

Algae live in association with microbes that interact by a variety of chemical mediators, resulting in mutualistic or antagonistic relationships. Although algae are key contributors to carbon fixation and are fundamental for food webs, we still know little about the underlying molecular mechanisms affecting their fitness. This study investigates the interaction between an antagonistic bacterium and a unicellular alga. It demonstrates multiple roles of a polyyne, protegencin, that is used by the bacteria to attack green algal cells. It is a highly effective toxin that alters a subcellular algal compartment used for vision, bleaches, and lyses the algal cells. These results expand our knowledge of the arsenal of chemical mediators in bacteria and their modes of action in algal communities.
A unifying autocatalytic network-based framework for bacterial growth laws
Authors: Roy Anjan , Goberman Dotan , Pugatch Rami
Published: August 2021

Significance

Bacterial cells contain various autocatalytic cycles, e.g., the ribosome cycle, where ribosomes translate ribosomal proteins that subsequently self-assemble to form new ribosomes. Here, we show that the transcription–translation machinery couples all cellular autocatalytic cycles, resulting in balanced exponential growth. Each autocatalytic cycle generates two types of growth laws. We derive the RNA polymerase (RNAP) growth law based on the RNAP autocatalytic cycle, where RNAPs transcribe messenger RNAs (mRNAs) of its constituent Rpo protein subunits. Before degrading, these mRNAs catalyze Rpo proteins employing ribosomes. The Rpo proteins subsequently self-assemble, forming new RNAPs, thus completing the cycle. Contrary to ribosome growth law, a reduction in growth rate due to shortage in RNAPs occurs without affecting the ribosomal protein mass fraction.
Community ecology and species interactions.
Authors: Rees Paul A.
Published: August 2021

This chapter contains questions about the structure of biological communities, their development over time, and the interactions between the species living within them, especially competition, niche separation and predation.
Ecological genetics and evolution.
Authors: Rees Paul A.
Published: August 2021

This chapter contains questions about the relationship between the genetics and ecology of organisms (including plants and animals), their adaptations to the environment, and their evolution.
Ecological methods and statistics.
Authors: Rees Paul A.
Published: August 2021

This chapter contains questions about the methods used by ecologists to sample and measure the biological components of ecosystems, and the statistical analysis of ecological data.
Grain size affecting the deformation characteristics via micro-injection upsetting
Authors: Abd-Elaziem Walaa , Hassan Mohsen A. , Makino Takehiko , Hamada Atef
Published: August 2021

The micro-injection upsetting (MIU) experiments of commercially pure aluminium have been conducted on two groups of specimens with different grain structures. One group is of coarse grain (CG, undeformed) and the other group is of fine grain (FG) achieved via the 4th pass equal channel angular pressing in micro-meso/scale. The two groups were further processed by micro/meso-scale extrusion before conducting MIU for fabricating tiny pins. Micro-upsetting test of the tiny pins showed that the material has a good isotropic flow forming and is free of undesirable defects comparing with the CG counterparts, which can be ascribed to the decreasing of grain boundary strengthening effect in the case of FG structure.
Superdiffusion in spin chains
Authors: Bulchandani Vir B , Gopalakrishnan Sarang , Ilievski Enej
Published: August 2021

This review summarizes recent advances in our understanding of anomalous transport in spin chains, viewed through the lens of integrability. Numerical advances, based on tensor-network methods, have shown that transport in many canonical integrable spin chains—most famously the Heisenberg model—is anomalous. Concurrently, the framework of generalized hydrodynamics has been extended to explain some of the mechanisms underlying anomalous transport. We present what is currently understood about these mechanisms, and discuss how they resemble (and differ from) the mechanisms for anomalous transport in other contexts. We also briefly review potential transport anomalies in systems where integrability is an emergent or approximate property. We survey instances of anomalous transport and dynamics that remain to be understood.
Experimental Fluid Dynamics Applications in Radial Turbomachines: Inlet Recirculation in Centrifugal Compressor, Rotating Stall and Flow in Vaneless Diffuser, and Improvement in Accuracy of CFD for Predicting Flow Fields in a Radial Turbine Rotor
Authors: Tamaki Hideaki , Ouchida Satoshi , Unno Masaru
Published: August 2021

Performance of a turbomachine strongly depends on its internal flow. CFD (Computational Fluid Dynamics) is now an essential tool obtaining information on such internal flow as well as its performance. However, when CFD is taken into a design process, the accuracy and feature of a CFD code must be understood. CFD requires EFD (Experimental Fluid Dynamics) for validating and ensuring its accuracy. Besides, EFD provides some empirical rules and models to complex phenomena that CFD needs high computational costs and long turnaround time and that are difficult to be integrated in a design work. Since CFD and EFD are complementary to each other, EFD with CFD or CFD with EFD serves as a powerful tool to understand flow phenomena in turbomachines. So, EFD is still important and frequently applied in industries to design and develop radial turbomachines. Examples of EFD conducted during the design of centrifugal compressors and radial turbines in the author’s affiliation are introduced here.
On the stability of boundary-layer flow over a rotating cone in an enforced axial free stream
Authors: Unadkat J , Hussain Z
Published: August 2021

Studies into the boundary-layer stability of rotating cones in an axial free stream have considered both cases of broad-angled cones and slender-angled ones. This distinction is made due to the findings that the dominant instability in the quiescent-fluid case results from different physical mechanisms for broad and slender cones. These investigations made use of an Orr-Sommerfeld-type analysis derived from the assumption of a small perturbation to a similarity-type solution for the mean fluid flow around the cone. In this work, we investigate the efficacy of a combination of sophisticated numerical techniques to find the basic flow, using ideas both from automatic differentiation and spectral collocation methods, to maximise the accuracy of the obtained solution. We inspect the solutions obtained for the Orr-Sommerfeld system in this setting and compare them to the results from previous studies.
Direct one-stage plasma-chemical synthesis of chalcogenide films doped with ytterbium
Authors: Kudryashov M A , Logunov A A , Mochalov L A
Published: August 2021

In this paper we descried the plasma-enhanced chemical vapor deposition (PECVD) approach for preparation of the arsenic sulfide thin films modified by ytterbium. Radio frequency (40.68 MHz) plasma discharge at low pressure (0.1 Torr) was used for the initiation of chemical interactions between precursors. Arsenic monosulfide (As4S4), elemental high-pure S and Yb were employed as the starting materials. The composition of the films was controlled by regulating of the temperature of the ytterbium source supplied with external heater. The Yb concentration in the Yb:AsxSy films was from 1 to 7 at%. The chalcogenide materials were also studied by Scanning Electron Microscopy (SEM), Optical spectroscopy in the range of 250-1000 nm, and Raman spectroscopy.
Creep of fine-grained carbonate concrete with a complex additive
Authors: Belov V V , Kuliaev P V , Barkaya T R
Published: August 2021

Fine-grained carbonate concretes (FGCC) have presently proved to be quite applicable with good parameters on crack- and freeze-thaw performance as criteria of durability and reliability of building materials and structures. The purpose to enhance deformative characteristics of FGCC is actually a search for economically and ecologically proven ways for it. The paper presents the results of strain’s study of fine-grained carbonate concretes with limestone fines and superplastisizer. Strains are classified as instant, short-term and long-term (creep). A method of planning experiment is used in the study. To measure strains, electric gauges and clock-type indicators were used. It was shown that a complex additive enhances both durability and performance of fine-grained carbonate concretes due to modification of their structure formation and hardening.
The surface piezoresponse of tetragonal tungsten bronze oxides with different ordering of cations in A-sublattice
Authors: Bunin M A , Bunina O A , Chumachenko K S
Published: August 2021

The piezoresponse (PR) images of microsized surface areas of the hot-pressed ceramics samples K4Bi2Nb10O30
, K2Sr4NbwO3
0, and Na2Sr4Nbl0O
30, presenting different types of the inter-octahedral cations ordering, were obtained. The Fourier analysis of the PR data showed that the mesoscale regions form subsystems responsible for the electrical activity of the sample, the contribution of which manifests itself depending on the type of cation ordering.
Long-term experience of construction and maintenance of buildings on extremely upheaval soils in the conditions of Minusinsk Hollow
Authors: Khalimov Oleg , Bozykova Vera
Published: August 2021

The paper presents the experience of the long-term observations on frosty heaving, the construction experience and the state of the structures during 38-40 years of maintenance of the buildings on bearing piles in extremely upheaval soils. The paper describes the experiment of using complex anti-heaving sheath from chemically treated soil as an anti-heaving stabilization. It also presents an example of uneven upheaval deformations of unloaded bearing piles, caused by the discordant bedding of the clayey soil. The paper analyzes the causes of uneven deformations of frosty heaving, the factors influencing the migration and water accumulation, the peculiarities of cryogenic structure formation on the boundary of the interaction of the treated and untreated soils.
The Cold Sintering Process of ZnO and BaTiO3 ceramics under the electric current influence
Authors: Smirnov A V , Ivakin Yu D , Kornyushin M V , Stolyarov V V
Published: August 2021

The paper presents the preliminary study results of the influence of the electric current (direct or alternating), the values of voltage and current, the presence or absence of activating additives, and external heating of the mold on the process of cold sintering of ZnO and BaTiO3 powders. The microstructures of the obtained samples are analyzed. Approaches to further research are proposed. The article substantiates the prospects for using electric current in the process of cold sintering of ceramics.
Analysis of existing approaches for describing the parameters of single sections during grinding
Authors: Bogutsky V B , Shron L B , Yagyayev E E
Published: August 2021

The paper presents an analysis of various approaches to the formation of an abrasive grain trace in the process of finishing abrasive processing. It is noted that the trace of abrasive grain has a significant impact on the working conditions of the tool and the output parameters of the process. It is established that in the process of interaction of abrasive grains and the processed material, sections can be formed both in the form of a comma and in the form of a segment, which cannot be obtained in real conditions of the processing. It is shown that such an approach to all types and modes of grinding can lead to significant errors in the calculations and, as a result, an incorrect assessment of the influence of processing modes on the technological parameters of the grinding process. The study shows the need to obtain analytical dependencies for calculating the size of individual sections when changing the distances between the contacting grains of the abrasive tool in a wide range.
Effect of graphene and temperature on friction coefficient of nanocomposite Al2O3 / graphene
Authors: Pakhomov M A , Stolyarov V V , Mezrin A M , Torskaya E V
Published: August 2021

The paper presents the results of tribological tests of sintered nanocomposite ceramics with 1 wt.% graphene and without graphene at room and higher temperatures. It is shown that graphene decreases friction coefficient. With an increase in the test temperature, the friction coefficient increased on samples with and without graphene.
Acetylsalicylic acid and its derivatives: the dynamics of the circulatory dimensions
Authors: Chuyan E N , Mironyuk I S , Ravaeva M Yu
Published: August 2021

The paper presents the research of the acetylsalicylic acid effect and its complex compounds with the metals of cobalt (Co2+), zinc (Zn2+), nickel (Ni2+) and manganese (Mn2+) at the multiple administration in the dose of 10 mg/kg on the indices of the central haemodynamics of the rats (heart rate; arterial pressure). It has been found out that a multifold administration of acetylsalicylic acid and salicylates of cobalt, zinc, nickel and manganese affect the indices of the rats’ central haemodynamics. The obtained data confirm the cardiac efficiency of new coordinating compounds, and have a further studying perspective of their biological effect in chronic experiments.
Gallium oxide thin films synthesis in different phase composition by gallium interaction with oxygen in oxygen-hydrogen plasma on silicon substrates
Authors: Mochalov L A , Logunov A A , Prokhorov I O
Published: August 2021

A modern synthesis method by plasma-chemical deposition of gallium oxide layers was developed. High-purity gallium was utilized as the source of gallium for moving by hydrogen flow into the reaction zone for interaction with oxygen in plasma discharge. Low temperature non-equilibrium RF (40MHz) plasma discharge was utilized for initiation interactions between precursors at a pressure of 0.1 Torr. The optical emission spectroscopy was used to assess the main excited particles formed in the gas phase. The paper researches the dependence of properties of the solid phase, grown on the silicon substrate, on the experimental parameters.
Formation mechanism of Ni-Cu-base coatings with diffusion alloying into low-melting liquid metal media solutions
Authors: Sokolov A G , Bobylyov E E , Storogenko I D
Published: August 2021

The paper shows the mechanism and kinetics of the formation of diffusion coatings deposited in the medium of low-melting liquid metal melts depend on the nature of the interaction of the elements forming the coatings with the elements of the coated steel. When applying a coating based on Ni-Cu, the following features were revealed: the presence of a process of carbon displacement by the coating elements deep into the coated material; the practical absence of the influence of the carbon concentration in steel on the coating formation process; the elements of the coated material that do not interact with the coating elements are pushed deep into the product. The paper presents a scheme for the formation of diffusion coatings. Formulas for calculating the diffusion fluxes and the coating thickness are presented.
Surface morphology of nanostructured zinc oxide materials obtained by plasma-enhanced chemical vapor deposition
Authors: Mochalov L A , Logunov A A , Prokhorov I O
Published: August 2021

Zinc oxide nanostructures have been obtained by plasma-enhanced chemical vapor deposition technique. High-purity elemental zinc was used as the precursor. RF (40MHz) inductively coupled plasma discharge was used for the initiation of the plasma-chemical reactions in the gas phase. Hydrogen-oxygen (H2-O2) composition of various ratios was used as the source plasma gas mixture. The optical emission spectroscopy was used as the powerful tool to determine the intermediate excited particles and assume the possible mechanism of the plasma-chemical reactions. The paper also investigates the influence of the substrate’s materials, its temperature, and the power of the heat input into the discharge. The properties of the sprayed materials were characterized by the method of atomic force microscopy.
Magnesia compositions with technogenic fillers
Authors: Miryuk O A
Published: August 2021

The paper presents the results of researching magnesia compositions, which contain caustic magnesite and porous technogenic fillers. The research is aimed at creating resource-saving magnesia materials with the density less than 1000 kg/m3. The dependence of the magnesia composition’s density and strength on the size of arboreal particles is exposed. The increase of the particles’ size lowers the density of materials, but worsens the moulding characteristics. The influence of ash microsphere on the structural and mechanical properties of magnesia materials is found out. The content of hollow particles in the magnesia mixture is restricted due to the decrease of the raw materials’ mass plasticity. The mathematical models, presenting the dependences of moulding mass’ properties and composition density on the filler’s composition, are obtained. The compositions of raw materials’ mixtures for getting materials with a reduced density are determined. Moulding masses, which contain the integral filler (20-50% of arboreal particles with the size 0.63-2.5 mm and 50-80% of the ash microsphere), are preferable. The combination of fibrous and spherical hollow particles provides mouldability of the raw materials’ mixture as well as a reduced density of magnesia compositions. The electronic microscopy is used to research the materials’ structure.
Deformation of the prefabricated monolithic cover from porous concrete reinforced with fiberglass fittings
Authors: Miryuk O A , Oleynik A I , Akhmedov K M
Published: August 2021

The paper studies the properties and the possibilities of using definite size thin-walled fasciae from the lightweight concrete, reinforced with one-layer fiberglass fittings, by numerical methods. The object of the research is a standard element of the prefabricated monolithic reticular cover’s clothing under the plane stress. Plane prefabricated cells have a hexagonal shape and ribbing that make a basis for a common reticular framework after the assembly of the cover. Strength properties of the model are studied at different reinforcement degrees. The paper also researches the possibilities of increasing the fittings’ adhesion ability due to the regular curved structure. The comparison of different reinforcement variants is presented. The distributive function of the contour ribbing on the stressed state of the standard element is evaluated. The paper also gives recommendations on the use of discrete thin-walled reinforced elements as the elements of the bearings’ covers in the structure of multilayer or multilayer membranate constructions.
Computer simulation of crystals formed from 4-6-12 and 5-7 fluorographene layers
Authors: Belenkov M E , Chernov V M
Published: August 2021

The three-dimensional structure of four fluorographene crystals was calculated by the atom-atom potential method. The crystals consisted of 4-6-12 or 5-7 graphene layers functionalized by fluorine packed in stacks. The structure of fluorographene layers of two polymorphs T1 and T3 for 4-6-12 layer and two polymorphs of 5-7 layer T1 and T2 was considered. The electronic structure was calculated by the density functional theory method in the generalized gradient approximation. As a result of the calculations, it was established that the interlayer distances in various fluorographene crystals vary in the range from 5.4921 to 5.7645 Å. In CF-L4-6-12 T1 crystals, the relative shift of adjacent layers is close to zero. In the remaining fluorographene crystals, the layer shift vector varies from 0.336 to 0.3714 nm. The energy of interlayer bonds per atom is minimal for CF-L5-7 crystal of T2 type and is -3024.44 J/mol. The maximum value of the binding energy is equal to -2291.35 J/mol and observed in CF-L4-6-12 crystals of T3 type. The sublimation energy varies from 13.83 to 14.24 eV, and the band gap from 2.827 to 3.682 eV. The band gap in CF crystals is 0.2--0.4 eV less than in isolated fluorographene layers.
The theoretical evaluation of new promising solid ion conductors for zinc-ion batteries
Authors: Morkhova Ye A , Kabanov A A , Leisegang T
Published: August 2021

Recently, we have screened the Inorganic Crystal Structure Database (ICSD, version 2020/1) to find new Zn2+-ion conductors. After a stepwise selection procedure, we have identified five most promising Zn-ion conductors ZnFe2O4, ZnV2O4, ZnCr2O4, ZnP2O6 and Zn3S2O9. In this work we describe the ion conductivity in the selected structures in detail by using of a set of methods: analysis of free space in crystals (geometrical-topological analysis, based on the Voronoi partitioning approach), calculation of the Zn2+-ion migration energy barrier within the bond valence site energy method, and calculation of the Zn2+-ion energy barriers within the density functional theory approach.
Modelling and Simulation Analysis of Drones Allocation for Bushfires
Authors: Wang Junxu , Weng Haisong , Yan Yuxin , Li Congduan
Published: August 2021

Recent years, bushfire has been more and more frequent because of climate changes. At the scene of fires, firefighters have used drones for surveillance. In this paper, a model is designed to determine the optimal number of drones needed for a bushfire based on the data from satellites. We design a greedy algorithm to plan the cruise lines with the minimal number of drones, covering the fire region. We divide a region (take Victoria, Australia as an example) into blocks, and analysed each block to get the average number of drones needed. We also model the fire probability distribution and finally determine the total number of drones that should be reserved. The simulation (The simulation code is publicly available via https://github.com/WRangers/msadab) results and analysis show the model is effective and can adapt to a real-time changing large-scale bushfire situation, adjusting the cruise scheme dynamically. The algorithm is helpful to make a budget on purchasing equipment, and also helps the fire department deploy drones in bushfires.
Simulation Study on Tensile Strength of Carbon Fiber Twisted Sewing Thread
Authors: Zhang Yinfei , Li Jing , Cao Lingling , Peng Zhen , Han Wendong
Published: August 2021

The twist of the suture is an important parameter that affects the suture effect. If the suture is not twisted, the suture is easy to wear and fluff during the sewing process, resulting in thread breakage. At the same time, that will affect the suture effect and the strength of the suture itself. The article uses experiments and simulations to compare the mechanical properties of carbon fiber twisted threads. Refer to GB/T 3362—"Test Method for Tensile Properties of Carbon Fiber Multifilament" to test the tensile strength of T700-12K carbon fiber tow. And in ABAQUS, the three-dimensional Hashin damage criterion is used for 20 twists/m, 50 The carbon fiber sewing thread with twists/m and 80 twists/m is subjected to finite element prediction. The results show that the carbon fiber sewing thread with 80 twists/m has higher tensile strength than the carbon fiber sewing thread with 20 twists/m and 50 twists/m.
Simulation on the Effect of Frequency and Ferromagnetic Tubes Specifications by Far Field Eddy Current Examination
Authors: Du Haoyang , Cui Lun , Yang Zhou , Zhu Daming
Published: August 2021

Tube leakage frequently occurred in on-service fossil power plants. Traditional NDT testing methods, including RT, UT, MT and PT are not applicable for the examination of large amount tubes. Fat eddy current examination is a new technique for testing ferromagnetic tubes defects, such as inner corrosion, thickness reduction and cracks. Far field eddy current simulation and verification for different specification tubes has been carried out. The result shows that the position of far field eddy current moves backwards with the increase of wall thickness and tube ID. To the defects with same size, examination sensitivity is higher in far field eddy current area. When the defect with same size locates in the inner and outer surface of the tube, the change of magnetic intensify differences is approximately the same, which is in accordance with the experimental result and is satisfied with far field eddy current examination theory. It has been concluded that defects in ferromagnetic tubes could be judged and recognized by far field eddy current examination technique, which shows prospective for the on-line examination and safety evaluation for in-service tubes in fossil power plants.
Rough Set-Fisher Discriminant Analysis Method for Prediction of Classification of Rock Burst Risk
Authors: Ping Jian
Published: August 2021

This paper introduces the rough set theory, combined with the Fisher discriminant method to more accurately predict the risk level of rock burst. Firstly, based on the example of Yanshitai coal mine in Chongqing, we determine the influencing factors of rock burst risk; then, the evaluation indicators are reduced by rough set theory to obtain the key attributes; finally, the reduced key attributes are used as the discriminant factors of the rough set-Fisher discriminant model to test. According to the research results, the rough set-Fisher discriminant analysis method eliminates redundant indicators and reduces the number of indicators after reducing the evaluation indicators, achieving efficient prediction of the risk level of rock burst.
Mechanical Properties Test and Simulation Analysis of Glass Coated Amorphous Filaments
Authors: Qin Shujuan , Yin Junqing , Liu Shan , Chen Yongdang , Gu Jinyu
Published: August 2021

Taking the Co68.7Fe4Ni1B13Si11Mo2.3 glass-coated amorphous microwire as the research object, the mechanical properties of the amorphous wire were tested through biaxial tensile experiments, and the fracture deformation process of the amorphous wire was analyzed. Based on the experimental data, the finite element method was used The simulation software ABAQUS numerically simulates the tensile deformation of the amorphous wire, and the fracture relationship between the glass cladding layer and the core wire, and further reveals the tensile deformation fracture behavior of the amorphous wire was analyzed. The experimental results indicate that the fabricated microwires exhibit good tensile properties, and the maximum tensile breaking strength can reach 2918MPa; the fracture of the amorphous wire is a typical brittle fracture, and there is no obvious yield phenomenon. The tensile mechanics simulation results of the amorphous wire are consistent with the experimental results. The glass cladding layer breaks before the core wire, and the stress transfer effect in the amorphous wire is good. The model fracture is consistent with the fracture morphology of the amorphous wire. These results show that the amorphous wire exhibits good tensile properties and stress transmission capabilities, confirming the huge application potential of amorphous wire materials in sensor applications and functional composite materials.
Spatial Optimization Information Security Algorithm for UAV Cluster Oriented to RSA
Authors: Luo Guilan , Zhu Yuanbo , Wang Shuailin , Li Zhongmu , Zhang Mei , Wang Xi
Published: August 2021

In the face of the limited communication and computing capacity of UAV network in complex environment, in order to improve the operating efficiency of UAV cluster information security algorithm, this paper proposes a spatial optimization information security algorithm for Public Key Cryptography (RSA). Firstly, the UAV location and cluster space optimization algorithm (CA-PSO) is used to obtain the UAV location. Secondly, the optimal particle of UAV swarm is found through spatial optimization. Then the optimal particle is loaded with the UAV Cluster Information Security Optimization Algorithm (RSA-UAV). Finally, the UAV network simulation process is given. Through algorithm simulation and performance analysis, it is found that the positioning accuracy and convergence of the loaded information security algorithm are better after the improved algorithm space optimization.
Single Image Super-resolution Reconstruction Algorithm Based on Deep Learning
Authors: Li Qinqin , Guo Xiaoming , Han Jiangxue , Zhang Xiaoyang , Liu Heng
Published: August 2021

Recover the high-resolution image from a single low-resolution image is known as single image super-resolution reconstruction (SISR). SSIR is currently a research hotspot in computer vision. In this paper, we study the feature learning module of the magnification-arbitrary network for Super-Resolution(Meta-SR), and propose an improved method of image feature learning. Its idea is multi-scale residual dense block (MRDB). We integrate it into the existing structure of the Meta-SR network. As a result, the same network has increased the receptive field, and it can obtain more detailed features of the image. This structure can be extended to other existing SISR network models. In the published and standard test set Set14, compared with the interpolation method, the average PSNR value of the algorithm in this paper increases by 3.79dB, 3.01dB and 2.85dB at amplification factors 2, 3 and 4, respectively. Through the analysis of SISR results, it can be obtained that the improved method proposed in this paper has a significant improvement in all indicators, and can more fully extract the image detail features, thereby improving the quality of the reconstructed image.
Optimization of Helicopter Rotor Airfoil Wind Tunnel Test Model Based on Intelligent Algorithm
Authors: Kong Peng , Peng Xiaoqiang , Zhang Weiguo , Lian Zhenzeng
Published: August 2021

The helicopter rotor wing wind tunnel test model is the basic equipment for helicopter wind tunnel test research. On the premise of meeting the requirements of corresponding strength, stiffness, natural frequency and stability, the model mass needs to be light enough to meet the requirements of heave vibration test. To this end, this paper proposes the structure of aluminum alloy skeleton + carbon fiber reinforced composite skin, and in order to obtain good performance, the following steps are used to optimize the parameters of the test model structure: 1. Establish an RBF neural network approximation model; 2. Use multiple island genetic algorithm (MIGA) and the sequential quadratic programming algorithm (SQP) are combined to optimize the thickness of the skeleton and composite materials. The optimization results show that the quality of the model is reduced by 34.05% under the condition that the corresponding requirements of strength, stiffness, natural frequency and stability are met.
A Data Compress Algorithm for Daisy Chain Communication System
Authors: Xu Ziyang , Wang Yu , Gong Ci , Chen Junkang , Zhou Jian , Lu Yi , Zhang Xinyu , He Longyu , Huang Zihao
Published: August 2021

In the era of big data, traditional data compression methods cannot complete data compression with features of large volume, rapid growth and complex structure, especially in the processing of real-time data compression. The compression algorithm proposed in this paper is improved on the basis of a lossless bit-swap compression coding algorithm. The coding algorithm is based on VAE model and uses classical ANS compression technology to code multiple potential variables, so as to realize the rapid compression and decompression of data. The experimental results show that the algorithm proposed in this paper can compress data with a high compression rate(47.65%), which is higher than LZAM algorithm and Bit-Swap algorithm.
Implicit Aspect Extraction from Online Clothing Reviews with Fine-tuning BERT Algorithm
Authors: Yu Li , Bai Xuefei
Published: August 2021

In the era of e-commerce, tremendous product reviews can provide quick and valuable insight into the market trends. Aspect-based sentiment analysis (ABSA) on product reviews is becoming increasingly important for both companies and consumers. Implicit aspect extraction, a subtask of ABSA, aims to identify the aspect of a review sentence without explicit aspect terms. For Chinese online reviews, this paper proposes a fine-tuning BERT based method to extract implicit aspects. Fine-tuning BERT performs well on a variety of natural language processing tasks. Using labeled data, the hidden layer parameters of pre-training BERT are fine-tuned in a supervised manner to generate fine-tuning BERT. Through experiments on Chinese online reviews of clothing, it is believed that fine-tuning BERT can improve the effect of implicit aspects identification.