PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019最新文献

{"title":"Effect of electron beam processing on structure of electroexplosion electroerosion-resistant ZnO-Ag coating","authors":"D. Romanov, S. V. Moskovskii, V. Gromov, Y. Ivanov, A. Semin","doi":"10.1063/1.5132162","DOIUrl":"https://doi.org/10.1063/1.5132162","url":null,"abstract":"The structure, phase composition and properties of the composite electroexplosion coating of ZnO-Ag system subjected to the irradiation by the high intense electron beam have been studied for the first time. The combined processing including the electroexplosion spraying of the coating of ZnO-Ag system and its subsequent electron beam processing results in the formation of multilayer structure of the coating. By the methods of metallography, scanning and transmission electron microscopy, X-ray structural analysis the investigations into the phase and elemental composition, defect substructure of the coating and the transition layer between the coatings and copper electrical contact have been carried out. The electron beam melts and homogenizes the surface layer of the composite electroexplosion coating of ZnO-Ag system to the depth of 35–40 µm. The effect of the electron beam leads to the formation of the nanocrystalline phases of Ag, ZnO, Cu, CuZn, Ag5Zn8, Cu2O, Ag2O, Cu0.67Zn0.33, AgZn.The structure, phase composition and properties of the composite electroexplosion coating of ZnO-Ag system subjected to the irradiation by the high intense electron beam have been studied for the first time. The combined processing including the electroexplosion spraying of the coating of ZnO-Ag system and its subsequent electron beam processing results in the formation of multilayer structure of the coating. By the methods of metallography, scanning and transmission electron microscopy, X-ray structural analysis the investigations into the phase and elemental composition, defect substructure of the coating and the transition layer between the coatings and copper electrical contact have been carried out. The electron beam melts and homogenizes the surface layer of the composite electroexplosion coating of ZnO-Ag system to the depth of 35–40 µm. The effect of the electron beam leads to the formation of the nanocrystalline phases of Ag, ZnO, Cu, CuZn, Ag5Zn8, Cu2O, Ag2O, Cu0.67Zn0.33, AgZn.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81171828","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}

{"title":"Combined Rayleigh–Taylor–Kelvin–Helmholtz instability and its role in the formation of the surface relief of the coating/substrate","authors":"V. Sarychev, S. Nevskii, A. Granovskii, S. Konovalov, V. Gromov","doi":"10.1063/1.5132174","DOIUrl":"https://doi.org/10.1063/1.5132174","url":null,"abstract":"The paper reports on an undulating topography initiating on the interface “coating/substrate material” under heterogeneous plasma flows to be generated by an explosion of yttrium powder on the titanium base. We assumed that an undulating topography on the interface resulted from a combination of Rayleigh–Taylor and Kelvin–Helmholtz instabilities. A flow of an incompressible viscous two-dimensional fluid was considered in the field of bulk forces. The first layer made up of titanium or silumin is thought to be static, and the second one is accelerated perpendicular to the base material plane. A range of transversal velocities in the second layer was determined, varying 0 to 55 m/s for systems Ti-Y. Navier–Stocks equation and boundary conditions were stated for each layer. In a system Ti-Y Rayleigh–Taylor instability dominates at a transversal velocity of below 10 m/s, changing into Kelvin–Helmholtz instability at velocities above 10 m/s. The study highlights importance of the transversal velocity in yttrium layer for reasoning of undulating pattern formation on the interface “coating/base material” and distribution of yttrium particles in depth of the modified layer.The paper reports on an undulating topography initiating on the interface “coating/substrate material” under heterogeneous plasma flows to be generated by an explosion of yttrium powder on the titanium base. We assumed that an undulating topography on the interface resulted from a combination of Rayleigh–Taylor and Kelvin–Helmholtz instabilities. A flow of an incompressible viscous two-dimensional fluid was considered in the field of bulk forces. The first layer made up of titanium or silumin is thought to be static, and the second one is accelerated perpendicular to the base material plane. A range of transversal velocities in the second layer was determined, varying 0 to 55 m/s for systems Ti-Y. Navier–Stocks equation and boundary conditions were stated for each layer. In a system Ti-Y Rayleigh–Taylor instability dominates at a transversal velocity of below 10 m/s, changing into Kelvin–Helmholtz instability at velocities above 10 m/s. The study highlights importance of the transversal velocity in yttriu...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86417470","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}

{"title":"Feedstock investigation based on SAE 316L steel bimodal powders and PLA/PMMA for injection molding: An experimental study","authors":"N. Toropkov, M. Lerner, E. Mironov","doi":"10.1063/1.5132234","DOIUrl":"https://doi.org/10.1063/1.5132234","url":null,"abstract":"This work studies the new polymer feedstock for the metal injection molding (MIM) process. The proposed feedstock is based on the bimodal powders of steel grade SAE 316L, polymethyl methacrylate (PMMA) and polylactide (PLA). The impact of PMMA content on the molding characteristics, thermal debinding and sintering of samples obtained by pressure casting is thoroughly investigated. It is found that the sintering density of the molded samples increases with the raise of PMMA content. It is shown that implementing the bimodal powder based composites in MIM applications results in samples with sinter density as high as 98%.This work studies the new polymer feedstock for the metal injection molding (MIM) process. The proposed feedstock is based on the bimodal powders of steel grade SAE 316L, polymethyl methacrylate (PMMA) and polylactide (PLA). The impact of PMMA content on the molding characteristics, thermal debinding and sintering of samples obtained by pressure casting is thoroughly investigated. It is found that the sintering density of the molded samples increases with the raise of PMMA content. It is shown that implementing the bimodal powder based composites in MIM applications results in samples with sinter density as high as 98%.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86633690","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}

{"title":"Effect of sphericity on the evaluation of the stress-strain state in the earth’s crust","authors":"Y. Stefanov, R. Bakeev, V. Suvorov, E. Melnik","doi":"10.1063/1.5132215","DOIUrl":"https://doi.org/10.1063/1.5132215","url":null,"abstract":"The effect of sphericity on the stress-strain state of the Earth’s crust was evaluated by adapting a numerical algorithm for the solution of a 2D boundary value problem using a calculation scheme constructed for the Cartesian coordinate system. The considered problem describes the stress-strain state of a three-layer block model of the Earth’s crust and upper mantle along the Tarim–Altai profile with a length of 2500 km and a depth of 90 km. The solutions obtained with regard to sphericity and for a rectangular region were compared. The calculation results showed a very weak effect of sphericity on the resulting surface topography and intracrustal boundaries. However, there was a significant difference in the values of the stress-strain state parameters, which reached 10% or more in separate zones.The effect of sphericity on the stress-strain state of the Earth’s crust was evaluated by adapting a numerical algorithm for the solution of a 2D boundary value problem using a calculation scheme constructed for the Cartesian coordinate system. The considered problem describes the stress-strain state of a three-layer block model of the Earth’s crust and upper mantle along the Tarim–Altai profile with a length of 2500 km and a depth of 90 km. The solutions obtained with regard to sphericity and for a rectangular region were compared. The calculation results showed a very weak effect of sphericity on the resulting surface topography and intracrustal boundaries. However, there was a significant difference in the values of the stress-strain state parameters, which reached 10% or more in separate zones.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84320851","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}

{"title":"Numerical analysis of the grain morphology and texture in 316L steel produced by selective laser melting","authors":"O. Zinovieva, A. Zinoviev","doi":"10.1063/1.5132274","DOIUrl":"https://doi.org/10.1063/1.5132274","url":null,"abstract":"For tailoring the mechanical properties of additively manufactured parts, we first need to understand and predict additively manufactured microstructures. The present paper aims at in-depth analysis of a three-dimensional (3D) grain structure and texture of 316L austenitic stainless steel produced by powder bed based additive manufacturing (AM). For this purpose, we adopt a 3D framework combining the finite difference (FD) thermal model and modified cellular automata (CA) approach for grain structure prediction. The 3D CAFD model is first validated against the experimental findings on 316L steel produced by selective laser melting. The specimen manufactured by applying a bi-directional scanning strategy is shown to exhibit a strong {110}〈001〉 Goss texture. Multiple re-melting of the bulk material with scanning backward and forward at least once is supposed to result in a tendency of large columnar grains to align with the build direction. The texture strength is shown to increase with the increasing build height, following the exponential trend, as well as the grain size in the transverse and scanning directions.For tailoring the mechanical properties of additively manufactured parts, we first need to understand and predict additively manufactured microstructures. The present paper aims at in-depth analysis of a three-dimensional (3D) grain structure and texture of 316L austenitic stainless steel produced by powder bed based additive manufacturing (AM). For this purpose, we adopt a 3D framework combining the finite difference (FD) thermal model and modified cellular automata (CA) approach for grain structure prediction. The 3D CAFD model is first validated against the experimental findings on 316L steel produced by selective laser melting. The specimen manufactured by applying a bi-directional scanning strategy is shown to exhibit a strong {110}〈001〉 Goss texture. Multiple re-melting of the bulk material with scanning backward and forward at least once is supposed to result in a tendency of large columnar grains to align with the build direction. The texture strength is shown to increase with the increasing build...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85938355","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}

{"title":"Interrelation between the grain boundary energy and the packing density in α-Fe","authors":"A. Bakulin, S. Kulkova","doi":"10.1063/1.5131895","DOIUrl":"https://doi.org/10.1063/1.5131895","url":null,"abstract":"Using ab initio approach interrelations between the grain boundary energy, the atomic packing density in the interface plane and the magnetic states of atoms was studied for and symmetrical tilt grain boundaries in α- Fe. In the latter case three variants of Σ5(210) GB was studied. It is shown that a decrease of the grain boundary energy is correlated with an increase of the packing density and a decrease of deviation of the magnetic moment of Fe atoms from bulk value. Additionally, the peculiarities of the interatomic interaction near GB plane are discussed.Using ab initio approach interrelations between the grain boundary energy, the atomic packing density in the interface plane and the magnetic states of atoms was studied for and symmetrical tilt grain boundaries in α- Fe. In the latter case three variants of Σ5(210) GB was studied. It is shown that a decrease of the grain boundary energy is correlated with an increase of the packing density and a decrease of deviation of the magnetic moment of Fe atoms from bulk value. Additionally, the peculiarities of the interatomic interaction near GB plane are discussed.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88442943","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}

{"title":"Formation of surface layers from highly entropic materials with shape memory effect","authors":"Z. Blednova, P. Rusinov","doi":"10.1063/1.5131902","DOIUrl":"https://doi.org/10.1063/1.5131902","url":null,"abstract":"To expand the practical use of high-entropy and material with shape memory effect (SME), we have developed a technology to form functionally oriented surface layers with five and six-component powder compositions CoCuTiZrHf, NiCoTiZrHf, NiCuTiZrHf, ZrCuNiCoTi, TiNiZrHfCoCu. The coatings were deposited under conditions of high-energy effects, including mechanical activation of the applied material, high-velocity oxygen-fuel spraying in a chamber with argon, followed by thermomechanical treatment in a single technological cycle on the patented equipment. Electron-microscopic and X-ray diffraction studies have shown that the obtained coatings correspond to SME materials with a grain size of 80–400 nm. In accordance with energy criterion, we have predicted the cyclic durability of steel samples with a surface layer made of multicomponent SME materials. We took into account the energy intensity of the coating material and the structural factor. The energy intensity of the alloy is determined by the thermodynamic characteristics and the state diagram of the systems. The structural factor is based on the analysis of the structural-phase state by the method of multifractal parametrization taking into account homogeneity, fractal dimensionality, adaptability.To expand the practical use of high-entropy and material with shape memory effect (SME), we have developed a technology to form functionally oriented surface layers with five and six-component powder compositions CoCuTiZrHf, NiCoTiZrHf, NiCuTiZrHf, ZrCuNiCoTi, TiNiZrHfCoCu. The coatings were deposited under conditions of high-energy effects, including mechanical activation of the applied material, high-velocity oxygen-fuel spraying in a chamber with argon, followed by thermomechanical treatment in a single technological cycle on the patented equipment. Electron-microscopic and X-ray diffraction studies have shown that the obtained coatings correspond to SME materials with a grain size of 80–400 nm. In accordance with energy criterion, we have predicted the cyclic durability of steel samples with a surface layer made of multicomponent SME materials. We took into account the energy intensity of the coating material and the structural factor. The energy intensity of the alloy is determined by the thermodynam...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91032705","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}

{"title":"Propagation of longitudinal and rod waves in cylinders from polycrystalline and single-crystal materials under dynamic loading","authors":"M. Krivosheina, E. Tuch","doi":"10.1063/1.5132049","DOIUrl":"https://doi.org/10.1063/1.5132049","url":null,"abstract":"The paper presents the results of numerical calculations of dynamic loading of thin cylindrical targets with a ratio of cylinder heights to its diameter 1 : 1 and 5 : 1. The propagation of elastic waves in cylinders with different ratios of heights to the radius of the VZhM8 single-crystal nickel alloy with cubic symmetry of properties in order to determine the propagation velocities of rod waves in the [001], [011] and [111] directions was simulated in this paper. The problem of loading of a target from VZhM8 by a steel projectile with a starting velocity was carried out by the finite element method in a three-dimensional formulation.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82935359","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}

{"title":"Obtaining of heteromodulus ZrC-based composite materials, their structure and properties","authors":"Y. Mirovoy, A. Burlachenko, S. Buyakova","doi":"10.1063/1.5132094","DOIUrl":"https://doi.org/10.1063/1.5132094","url":null,"abstract":"The article is devoted to the impact of carbon additives on densification and mechanical properties of ZrC/C hetero-modulus composites. In case of addition of small amount of carbon to ZrC residual porosity decreases, whereas higher carbon content leads to more than 3vol.% increase in residual porosity. Moreover, increase in carbon content in ZrC/C composites enhance oughness of sintered materials. For example, КIC = 4.3 MPa×m1/2 for ZrC and КIC = 7 MPa×m1/2. for 3 vol.% C. For 15 vol.% of C, toughness is the lowest and equals 5.3 MPa×m1/2. The extrapolation of the dependence of toughness on the non-porous state of materials is КIC0 = 13.2 MPa×m1/2.The article is devoted to the impact of carbon additives on densification and mechanical properties of ZrC/C hetero-modulus composites. In case of addition of small amount of carbon to ZrC residual porosity decreases, whereas higher carbon content leads to more than 3vol.% increase in residual porosity. Moreover, increase in carbon content in ZrC/C composites enhance oughness of sintered materials. For example, КIC = 4.3 MPa×m1/2 for ZrC and КIC = 7 MPa×m1/2. for 3 vol.% C. For 15 vol.% of C, toughness is the lowest and equals 5.3 MPa×m1/2. The extrapolation of the dependence of toughness on the non-porous state of materials is КIC0 = 13.2 MPa×m1/2.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84066610","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}

{"title":"Microstructure and mechanical properties of the aluminum-zirconium tungstate composite","authors":"A. Kulkov, R. Balokhonov, V. Romanova, V. Shadrin, S. O. Kasparyan","doi":"10.1063/1.5132058","DOIUrl":"https://doi.org/10.1063/1.5132058","url":null,"abstract":"Deformation and fracture of particle-reinforced aluminum-zirconium tungstate metal-matrix composite are experimentally and numerically investigated. The composite material was fabricated using pure aluminum ACD-6 and ZrW2O8 powders mixed in proportions 90% and 10%, respectively. Mechanical tests on compression of the composite specimens were carried out, and the microstructure was investigated before and after the tests. Numerical simulation of the composite deformation was performed in two dimensional formulation of the dynamic boundary-value problem. Experimentally observed microstructure is included in calculations in an explicit form. Plastic strain localization and fracture in the matrix and particles were studied.Deformation and fracture of particle-reinforced aluminum-zirconium tungstate metal-matrix composite are experimentally and numerically investigated. The composite material was fabricated using pure aluminum ACD-6 and ZrW2O8 powders mixed in proportions 90% and 10%, respectively. Mechanical tests on compression of the composite specimens were carried out, and the microstructure was investigated before and after the tests. Numerical simulation of the composite deformation was performed in two dimensional formulation of the dynamic boundary-value problem. Experimentally observed microstructure is included in calculations in an explicit form. Plastic strain localization and fracture in the matrix and particles were studied.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77851528","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}