Pub Date : 2022-06-01DOI: 10.17804/2410-9908.2022.3.036-046
K. A. Mushankova, L. Stepanova
The main goal of the study is the atomistic determination of the static stress-strain state at the crack tip in isotropic and anisotropic linearly elastic materials by the molecular dynamics method implemented in the open source LAMMPS (Large-scale Atomistic/Molecular Massively Parallel Simulator). An extensive class of computational experiments has been carried out for a single-crystal copper specimen with a central crack in the LAMMPS. The circumferential distributions of the stress tensor components obtained by molecular dynamics are compared with the angular distributions of brittle fracture continuum mechanics, i.e. with Williams’ analytical solution to the problem of an infinite plate loaded with a central crack in a linearly elastic isotropic material. The comparison of the angular distributions of the stress tensor components gained in the framework of atomistic modeling and the angular distributions obtained from the classical solution of continuum mechanics has shown that, at the nanoscale level, the stress fields are in good agreement with their macroscopic values.
{"title":"Atomistic determination of stress fields in samples with defects","authors":"K. A. Mushankova, L. Stepanova","doi":"10.17804/2410-9908.2022.3.036-046","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.3.036-046","url":null,"abstract":"The main goal of the study is the atomistic determination of the static stress-strain state at the crack tip in isotropic and anisotropic linearly elastic materials by the molecular dynamics method implemented in the open source LAMMPS (Large-scale Atomistic/Molecular Massively Parallel Simulator). An extensive class of computational experiments has been carried out for a single-crystal copper specimen with a central crack in the LAMMPS. The circumferential distributions of the stress tensor components obtained by molecular dynamics are compared with the angular distributions of brittle fracture continuum mechanics, i.e. with Williams’ analytical solution to the problem of an infinite plate loaded with a central crack in a linearly elastic isotropic material. The comparison of the angular distributions of the stress tensor components gained in the framework of atomistic modeling and the angular distributions obtained from the classical solution of continuum mechanics has shown that, at the nanoscale level, the stress fields are in good agreement with their macroscopic values.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"100 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91179500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-01DOI: 10.17804/2410-9908.2022.2.021-034
V. Nazarov
Experimental data obtained at different times by the author for various titanium alloys are collected in one place. The mechanical properties of the VT1-0 alloy at normal temperature, the creep and creep rupture of the VT5 and VT6 alloys at 650 °C, the secondary creep of the VT1-0 alloy under complex stress conditions at 550 °C are considered. The final values of strains observed either at the rupture time or at mechanical test termination are taken as a criterion for combining all these data.
{"title":"Review of the author’s own results obtained from mechanical testing of titanium alloys","authors":"V. Nazarov","doi":"10.17804/2410-9908.2022.2.021-034","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.2.021-034","url":null,"abstract":"Experimental data obtained at different times by the author for various titanium alloys are collected in one place. The mechanical properties of the VT1-0 alloy at normal temperature, the creep and creep rupture of the VT5 and VT6 alloys at 650 °C, the secondary creep of the VT1-0 alloy under complex stress conditions at 550 °C are considered. The final values of strains observed either at the rupture time or at mechanical test termination are taken as a criterion for combining all these data.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84742658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-01DOI: 10.17804/2410-9908.2022.2.035-044
V. Zimina, I. Smolin
The paper discusses the problem of taking into account the influence of the heterogeneous structure of a material on its effective characteristics and mechanical behavior. To evaluate the effective properties and features of the stress and strain analysis of porous materials, it is proposed to use a combined method that includes experimental data (an SEM image of a porous material surface) and numerical methods of solids mechanics. Numerical simulation of the mechanical behavior of porous ceramics is performed on the basis of experimental data on its pore structure. As a result of the performed research, it is shown that this method makes it possible to determine the features of the stress and strain state of porous ceramics. The stress analysis reveals both tensile and compressive local stresses in porous ceramics mesovolumes under uniaxial tension. At the same time, the values of these local stresses exceed the mesovolume-average values by an order of magnitude.
{"title":"Features of the stress state of porous brittle materials under tensile conditions","authors":"V. Zimina, I. Smolin","doi":"10.17804/2410-9908.2022.2.035-044","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.2.035-044","url":null,"abstract":"The paper discusses the problem of taking into account the influence of the heterogeneous structure of a material on its effective characteristics and mechanical behavior. To evaluate the effective properties and features of the stress and strain analysis of porous materials, it is proposed to use a combined method that includes experimental data (an SEM image of a porous material surface) and numerical methods of solids mechanics. Numerical simulation of the mechanical behavior of porous ceramics is performed on the basis of experimental data on its pore structure. As a result of the performed research, it is shown that this method makes it possible to determine the features of the stress and strain state of porous ceramics. The stress analysis reveals both tensile and compressive local stresses in porous ceramics mesovolumes under uniaxial tension. At the same time, the values of these local stresses exceed the mesovolume-average values by an order of magnitude.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83973445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-01DOI: 10.17804/2410-9908.2022.2.006-020
A. D. Bratsun, D. Bratsun, I. Krasnyakov
The development of computer technologies makes it possible to implement a mathematical model of tissue dynamics, which includes the behavior of individual cells. The paper describes a mathematical model of a quasi-two-dimensional tissue, which consists of cells represented by dynamically changing polygons. The model includes two important processes that mimic the properties of real cells, namely mitotic division and intercalation. An equation of motion based on the elastic potential energy is written for each vertex of the polygonal cell. In the course of evolution, the tissue tends to take a position corresponding to the minimum of potential energy. The model allows a simple extension to the case of the feedback between the biomechanical and chemical properties of the medium and the introduction of several competing tissue types. The results of numerical simulation of heterogeneous carcinoma of the solid type are given as an example. The prospects for the development of this approach to simulation are discussed.
{"title":"Microscopic simulation of the chemomechanics of squamous cell tissue","authors":"A. D. Bratsun, D. Bratsun, I. Krasnyakov","doi":"10.17804/2410-9908.2022.2.006-020","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.2.006-020","url":null,"abstract":"The development of computer technologies makes it possible to implement a mathematical model of tissue dynamics, which includes the behavior of individual cells. The paper describes a mathematical model of a quasi-two-dimensional tissue, which consists of cells represented by dynamically changing polygons. The model includes two important processes that mimic the properties of real cells, namely mitotic division and intercalation. An equation of motion based on the elastic potential energy is written for each vertex of the polygonal cell. In the course of evolution, the tissue tends to take a position corresponding to the minimum of potential energy. The model allows a simple extension to the case of the feedback between the biomechanical and chemical properties of the medium and the introduction of several competing tissue types. The results of numerical simulation of heterogeneous carcinoma of the solid type are given as an example. The prospects for the development of this approach to simulation are discussed.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76140633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-01DOI: 10.17804/2410-9908.2022.2.055-066
V. V. Struzhanov, A. Chaikin
An analytical method has been developed for determining the moment of destruction of thin pipe coatings whose material retains elasticity during cyclic changes in internal pressure. The coating material has the property of strain softening, that is, destruction with increasing deformation occurs as stresses drop. The properties of the coating material are described by a convex-concave potential. Due to damage accumulation resulting from fatigue loading, the properties of the coating material change. Hence, the complete deformation curve degenerates. To determine the moment of destruction, the methods of the mathematical theory of catastrophes are used, which make it possible to find all the equilibrium positions of the system and the point of instability of the deformation process. Due to the degeneration of the properties of the coating material, the catastrophe (loss of stability) approaches the parameters of fatigue loading.
{"title":"Destruction of a protective pipe coating under cyclic loading by internal pressure","authors":"V. V. Struzhanov, A. Chaikin","doi":"10.17804/2410-9908.2022.2.055-066","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.2.055-066","url":null,"abstract":"An analytical method has been developed for determining the moment of destruction of thin pipe coatings whose material retains elasticity during cyclic changes in internal pressure. The coating material has the property of strain softening, that is, destruction with increasing deformation occurs as stresses drop. The properties of the coating material are described by a convex-concave potential. Due to damage accumulation resulting from fatigue loading, the properties of the coating material change. Hence, the complete deformation curve degenerates. To determine the moment of destruction, the methods of the mathematical theory of catastrophes are used, which make it possible to find all the equilibrium positions of the system and the point of instability of the deformation process. Due to the degeneration of the properties of the coating material, the catastrophe (loss of stability) approaches the parameters of fatigue loading.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"238 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91517671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-01DOI: 10.17804/2410-9908.2022.2.045-054
E. Baymetova
With the development of industry, the need to improve the efficiency of oil coolers is particularly increasing, due primarily to the rising cost of equipment, as well as increased attention to the issues of resource and energy saving. Oil coolers should not only perform the required functions of oil cooling, but also be as reliable and environmentally friendly as possible. Meanwhile, the majority of serial oil coolers are designed on the basis of outdated technical solutions, and this predetermines the levels of efficiency and reliability of their work as not corresponding to modern requirements. In this connection, the issues of hydrodynamics and heat exchange in finned tubes of oil coolers and refinement of methods of their calculation are relevant both for modernization of existing devices and for design of new oil coolers.
{"title":"Determination of optimal design parameters of a heat exchanging section by numerical modeling","authors":"E. Baymetova","doi":"10.17804/2410-9908.2022.2.045-054","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.2.045-054","url":null,"abstract":"With the development of industry, the need to improve the efficiency of oil coolers is particularly increasing, due primarily to the rising cost of equipment, as well as increased attention to the issues of resource and energy saving. Oil coolers should not only perform the required functions of oil cooling, but also be as reliable and environmentally friendly as possible. Meanwhile, the majority of serial oil coolers are designed on the basis of outdated technical solutions, and this predetermines the levels of efficiency and reliability of their work as not corresponding to modern requirements. In this connection, the issues of hydrodynamics and heat exchange in finned tubes of oil coolers and refinement of methods of their calculation are relevant both for modernization of existing devices and for design of new oil coolers.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77796166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.17804/2410-9908.2022.1.006-015
O. Klimova
The paper studies the optimization possibilities of an approach which made it possible to develop a formal tool, i.e. a model of computation organization for digital signal processing (DSP) operations and operations structurally similar to them. The resulting formal tool describes the inter-nal parameterized structure of operations and generates adaptive algorithms that can adjust to dif-ferent conditions of parallel computation. The developed approach to the construction of such algo-rithms endows them with extended functionality, which ensures the implementation of the follow-ing capabilities: changes in the parameters of algorithm structures; synthesis of their variety; opti-mization of variants of computation organization. Due to the variety of this functionality, several directions are identified for implementing this optimization. A general description of the optimiza-tion approach to the reasonable choice of the best variant of computation organization under the given conditions of their implementation is given. We consider a scheme of actions aimed at com-putation optimization and enabling you to develop various classes of parameterized parallel algo-rithms within the framework of the approach proposed.
{"title":"An optimization approach to the development of parallel algorithms for digital signal processing operations","authors":"O. Klimova","doi":"10.17804/2410-9908.2022.1.006-015","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.1.006-015","url":null,"abstract":"The paper studies the optimization possibilities of an approach which made it possible to develop a formal tool, i.e. a model of computation organization for digital signal processing (DSP) operations and operations structurally similar to them. The resulting formal tool describes the inter-nal parameterized structure of operations and generates adaptive algorithms that can adjust to dif-ferent conditions of parallel computation. The developed approach to the construction of such algo-rithms endows them with extended functionality, which ensures the implementation of the follow-ing capabilities: changes in the parameters of algorithm structures; synthesis of their variety; opti-mization of variants of computation organization. Due to the variety of this functionality, several directions are identified for implementing this optimization. A general description of the optimiza-tion approach to the reasonable choice of the best variant of computation organization under the given conditions of their implementation is given. We consider a scheme of actions aimed at com-putation optimization and enabling you to develop various classes of parameterized parallel algo-rithms within the framework of the approach proposed.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"119 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86179875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.17804/2410-9908.2022.1.025-037
S. Gladkovsky, I. Kamantsev, V. Veselova, Yu. V. Khudorozhkova
X-ray diffraction analysis, EBSD technique, and transmission electron microscopy are used to reveal the features of phase and microstructural transformations developing in plastic strain and fracture zones of the 05G20S2 metastable steel (Fe-20Mn-2Si). The dependence of the phase composition of the steel on the fatigue fracture surface on the value range of the stress intensity coefficient at the fatigue crack tip is determined.
{"title":"Martensitic transformations in plastic and fracture zones of the 05g20s2 metastable steel during cyclic tests","authors":"S. Gladkovsky, I. Kamantsev, V. Veselova, Yu. V. Khudorozhkova","doi":"10.17804/2410-9908.2022.1.025-037","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.1.025-037","url":null,"abstract":"X-ray diffraction analysis, EBSD technique, and transmission electron microscopy are used to reveal the features of phase and microstructural transformations developing in plastic strain and fracture zones of the 05G20S2 metastable steel (Fe-20Mn-2Si). The dependence of the phase composition of the steel on the fatigue fracture surface on the value range of the stress intensity coefficient at the fatigue crack tip is determined.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"131 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74193458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.17804/2410-9908.2022.1.052-066
A. Gorshkov, E. Prosviryakov
An inhomogeneous analytical solution describing a stratified large-scale isothermal Ekman–Poiseuille flow of a viscous incompressible fluid in the equatorial zone is obtained. A set of stagnation points of this solution is studied. Temperature is set at the flow boundaries. Tangential stresses simulating the effect of wind are specified at the free boundary. The Navier slip conditions are specified on the solid surface. The solution is constructed in the form of functions, linear in horizontal coordinates, with the coefficients dependent on the vertical coordinate. The coefficients of the linear functions are obtained as polynomials. The condition of consistency of the overdetermined equation system describing the specified flow is obtained. The consistency condition imposes restrictions on the boundary conditions. It is shown that the set of stagnation points lies on a straight line.
{"title":"Stagnation points of an inhomogeneous solution describing convective Ekman flow in the oceanic equatorial zone","authors":"A. Gorshkov, E. Prosviryakov","doi":"10.17804/2410-9908.2022.1.052-066","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.1.052-066","url":null,"abstract":"An inhomogeneous analytical solution describing a stratified large-scale isothermal Ekman–Poiseuille flow of a viscous incompressible fluid in the equatorial zone is obtained. A set of stagnation points of this solution is studied. Temperature is set at the flow boundaries. Tangential stresses simulating the effect of wind are specified at the free boundary. The Navier slip conditions are specified on the solid surface. The solution is constructed in the form of functions, linear in horizontal coordinates, with the coefficients dependent on the vertical coordinate. The coefficients of the linear functions are obtained as polynomials. The condition of consistency of the overdetermined equation system describing the specified flow is obtained. The consistency condition imposes restrictions on the boundary conditions. It is shown that the set of stagnation points lies on a straight line.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"146 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73403697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.17804/2410-9908.2022.1.038-051
V. Nazarov
The paper reviews studies conducted between 2004 and 2021 for various metal materials (magnesium-lithium alloy, copper, aluminum alloy, titanium alloy, steel, nickel alloy) in the temperature range from 20 to 1100 °C. In those studies the test results were obtained for isothermal creep under uniaxial tension and complex stress. The number of such studies is limited. This review does not include studies dealing with the chemical interaction of the environment with a metal material. Among these studies there are little-known and unique results. In one of those studies, the creep of a magnesium-lithium alloy at normal temperature was considered for the first time. In another study, creep curves for heat-resistant steel were supplemented with experimental stress–strain diagrams in a wide range of high temperatures. Another distinctive study, for the characteristic times of the creep process, compares photographs of changes in the microstructure and the creep curve up to the rupture time. The review lists studies that found an ambiguity in the effect of biaxial tension on the rupture time in comparison with uniaxial tension. It enumerates complex equivalent stresses with the possibility of describing the relative difference in the rupture time under uniaxial tension, biaxial tension, and triaxial tension.
{"title":"A review of experimental studies of creep and creep rupture strength (2004–2021)","authors":"V. Nazarov","doi":"10.17804/2410-9908.2022.1.038-051","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.1.038-051","url":null,"abstract":"The paper reviews studies conducted between 2004 and 2021 for various metal materials (magnesium-lithium alloy, copper, aluminum alloy, titanium alloy, steel, nickel alloy) in the temperature range from 20 to 1100 °C. In those studies the test results were obtained for isothermal creep under uniaxial tension and complex stress. The number of such studies is limited. This review does not include studies dealing with the chemical interaction of the environment with a metal material. Among these studies there are little-known and unique results. In one of those studies, the creep of a magnesium-lithium alloy at normal temperature was considered for the first time. In another study, creep curves for heat-resistant steel were supplemented with experimental stress–strain diagrams in a wide range of high temperatures. Another distinctive study, for the characteristic times of the creep process, compares photographs of changes in the microstructure and the creep curve up to the rupture time. The review lists studies that found an ambiguity in the effect of biaxial tension on the rupture time in comparison with uniaxial tension. It enumerates complex equivalent stresses with the possibility of describing the relative difference in the rupture time under uniaxial tension, biaxial tension, and triaxial tension.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"683 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91449066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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