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

{"title":"Metal powder composite based on 316L stainless steel bimodal powder","authors":"N. Toropkov, E. Glazkova, N. Rodkevich, A. Pervikov, M. Lerner, S. Muzhetskaya, S. Ghyngazov","doi":"10.1063/1.5132233","DOIUrl":"https://doi.org/10.1063/1.5132233","url":null,"abstract":"Metal powder composites for Powder injection molding (PIM) technology have been investigated. 316L stainless steel bimodal powder, obtained by electric explosion of the wire and multicomponent binder comprising PMMA, PE-LD and Viscowax were used to obtain feedstocks. The effect of PMMA content in the binder on the properties of feedstocks and sintered parts has been studied. As the PMMA content increases, the molding temperature of the parts rises from 140 to 200°C, the strength of the “green” and “brow” parts increases as well. The optimal PMMA content in the binder has been found to be 15–20 vol %. “Brown” samples sintered in vacuum at 1300°C exhibit shrinkage up to 23% and the samples density reaches 0.98 TD. Samples of feedstocks were characterized by TEM, SEM, DSC-TG methods.Metal powder composites for Powder injection molding (PIM) technology have been investigated. 316L stainless steel bimodal powder, obtained by electric explosion of the wire and multicomponent binder comprising PMMA, PE-LD and Viscowax were used to obtain feedstocks. The effect of PMMA content in the binder on the properties of feedstocks and sintered parts has been studied. As the PMMA content increases, the molding temperature of the parts rises from 140 to 200°C, the strength of the “green” and “brow” parts increases as well. The optimal PMMA content in the binder has been found to be 15–20 vol %. “Brown” samples sintered in vacuum at 1300°C exhibit shrinkage up to 23% and the samples density reaches 0.98 TD. Samples of feedstocks were characterized by TEM, SEM, DSC-TG methods.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89709182","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":"Cyclic strength of joints from SS 321 obtained by laser-arc hybrid welding","authors":"A. Gusarova, A. V. Chumaevski, A. N. Ivanov, L. Zhukov, V. Beloborodov","doi":"10.1063/1.5131997","DOIUrl":"https://doi.org/10.1063/1.5131997","url":null,"abstract":"Deformation and fracture regularities of samples from stainless steel 321 during fatigue testing are investigated. It is revealed that during the cyclic tensile tests according to the scheme “loading-unloading” the samples demonstrate high cycle life in the range of maximum stresses in the cycle from 0.65 UTS to 0.70 UTS. At the stresses of 0.75-0.80 UTS the samples are characterized by lower level of cycle life. It is revealed, that the specimen fracture is localized in the weld seam area. At different values of maximum stress, it is possible both to fracture with a neck formation, and purely fatigue rupture.Deformation and fracture regularities of samples from stainless steel 321 during fatigue testing are investigated. It is revealed that during the cyclic tensile tests according to the scheme “loading-unloading” the samples demonstrate high cycle life in the range of maximum stresses in the cycle from 0.65 UTS to 0.70 UTS. At the stresses of 0.75-0.80 UTS the samples are characterized by lower level of cycle life. It is revealed, that the specimen fracture is localized in the weld seam area. At different values of maximum stress, it is possible both to fracture with a neck formation, and purely fatigue rupture.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89321923","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":"Computer simulation of quantum technologies: The interaction of diatomic A2 molecules (A = C, Si, N, P, O, S) with single-wall carbon nanotube sensor","authors":"O. Maslova, S. Beznosyuk, A. Masalimov","doi":"10.1063/1.5132084","DOIUrl":"https://doi.org/10.1063/1.5132084","url":null,"abstract":"Computer simulation of the interaction of diatomic A2 molecules (A = C, Si, N, P, O, S) with a super-small single-walled carbon nanotube (SWCNT) sensor was performed. The nonlocal density functional B3LYP / 3-21G (ORCA package) was used to study the supratomical nanosystem. For all molecules, it has been shown that the most preferable orientation of their axis is perpendicular to the outer surface of the SWCNT. Significant differences were found in the adsorption of molecules of group IV a (C, Si), group V a (N, P) and group VI a (O, S) of the periodic table of elements. The calculation showed that the chemisorption of the molecules C2 and Si is characterized by binding energies of 2.91 eV, 1.51 eV and equilibrium distances from the SWCNT surface of 1.39 A and 2.91 A, respectively. For a C2 molecule, a covalent bond with a pair of carbon atoms is preferred, while for a Si2 molecule, a covalent bond with one of the carbon atoms is more stable. In turn, for the N2, P2, O2, S2 molecules, it is preferable to be located in the center of carbon sextet at a distance from the surface of the SWCNT: 3.00 A, 3.17 A, 2.66 A, 2.96 A with binding energy: 0.15 eV, 0.27 eV, 0.39 eV, 0.52 eV, respectively.Computer simulation of the interaction of diatomic A2 molecules (A = C, Si, N, P, O, S) with a super-small single-walled carbon nanotube (SWCNT) sensor was performed. The nonlocal density functional B3LYP / 3-21G (ORCA package) was used to study the supratomical nanosystem. For all molecules, it has been shown that the most preferable orientation of their axis is perpendicular to the outer surface of the SWCNT. Significant differences were found in the adsorption of molecules of group IV a (C, Si), group V a (N, P) and group VI a (O, S) of the periodic table of elements. The calculation showed that the chemisorption of the molecules C2 and Si is characterized by binding energies of 2.91 eV, 1.51 eV and equilibrium distances from the SWCNT surface of 1.39 A and 2.91 A, respectively. For a C2 molecule, a covalent bond with a pair of carbon atoms is preferred, while for a Si2 molecule, a covalent bond with one of the carbon atoms is more stable. In turn, for the N2, P2, O2, S2 molecules, it is preferable to ...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87590237","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":"Ultrasonic agglomeration-fragmentation of diamond nanoparticles","authors":"O. Kudryashova, A. Vereshchagin, A. V. Balakhnina, E. A. Petrov","doi":"10.1063/1.5132056","DOIUrl":"https://doi.org/10.1063/1.5132056","url":null,"abstract":"A lot of practical applications of nanoparticles assume a technological stage of introduction of particles into liquid. Meanwhile, particles could have a poor wettability. Nanostructural agglomerates contain micro- and nanopores filled with air. External impact is necessary to defragment these agglomerates. Ultrasonic treatment is often used for these purposes. Ultrasonic impact can break the agglomerate to original particles and can serve coagulation and growth of the sizes of the agglomerate. We have found the criterion of the leading mechanism (fragmentation or agglomeration) at ultrasonic processing of suspensions of nanodiamond in this work. Dynamics of the change of particles’ sizes at ultrasonic processing is considered theoretically and experimentally.A lot of practical applications of nanoparticles assume a technological stage of introduction of particles into liquid. Meanwhile, particles could have a poor wettability. Nanostructural agglomerates contain micro- and nanopores filled with air. External impact is necessary to defragment these agglomerates. Ultrasonic treatment is often used for these purposes. Ultrasonic impact can break the agglomerate to original particles and can serve coagulation and growth of the sizes of the agglomerate. We have found the criterion of the leading mechanism (fragmentation or agglomeration) at ultrasonic processing of suspensions of nanodiamond in this work. Dynamics of the change of particles’ sizes at ultrasonic processing is considered theoretically and experimentally.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88311974","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":"Study of the structural inhomogeneity of bimetal layers at the yield plateau stage","authors":"Yulia Li, S. Barannikova, G. Shlyakhova, L. Zuev","doi":"10.1063/1.5132063","DOIUrl":"https://doi.org/10.1063/1.5132063","url":null,"abstract":"The paper studies the kinetics of Chernov–Luders band propagation of bimetallic material on the yield plateau at the microscale level. The localization patterns of plastic deformation in the process of uniaxial tension are obtained by noncontact method of recording the fields of displacement vectors. Microstructure of the interfaces studied by atomic force microscopy showed that in the direction of the pearlite steel to the austenitic form there are structural components: the weakened zone of the ferrite layer; hardened section of the ferrite layer dark-pickling layer from the side of austenitic steel. Plastic deformation of a bimetal begins from the nucleation of the Luders band on the boundaries of the bimetal on stress raisers with higher hardness due to the diffusion effect. In the main layer the Luders band is limited to a pair of fronts moving in opposite directions along the bimetal axis with different velocities. The cladding layer does not suppress the formation of Luders bands, leads to an increase in the propagation velocity of Luders band fronts in the base layer and reduces the Luders band propagation in all bimetal layers.The paper studies the kinetics of Chernov–Luders band propagation of bimetallic material on the yield plateau at the microscale level. The localization patterns of plastic deformation in the process of uniaxial tension are obtained by noncontact method of recording the fields of displacement vectors. Microstructure of the interfaces studied by atomic force microscopy showed that in the direction of the pearlite steel to the austenitic form there are structural components: the weakened zone of the ferrite layer; hardened section of the ferrite layer dark-pickling layer from the side of austenitic steel. Plastic deformation of a bimetal begins from the nucleation of the Luders band on the boundaries of the bimetal on stress raisers with higher hardness due to the diffusion effect. In the main layer the Luders band is limited to a pair of fronts moving in opposite directions along the bimetal axis with different velocities. The cladding layer does not suppress the formation of Luders bands, leads to an incre...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"93 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79586971","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 treatment of an injection well of the Usinskoye oilfield with acid GBK composition on the oil recovery and properties of produced fluids","authors":"V. S. Ovsyannikova, E. A. Rozhdestvensky, L. Strelets, I. Kuvshinov, L. Altunina","doi":"10.1063/1.5132126","DOIUrl":"https://doi.org/10.1063/1.5132126","url":null,"abstract":"An acid composition of prolonged-action based on an inorganic acid adduct, a polyol and a surfactant has been developed at the Institute of Petroleum Chemistry, SB RAS. Introduced into the injection well, the composition exerts a prolonged positive effect on the oil recovery in the area of its influence. The increase in oil production rates and decrease in water cuts are accompanied by changes in viscosity of extracted oil and mineral composition of produced water. The appearance of components of a new composition and products of its hydrolysis in the produced fluids suggests the inclusion of still virgin zones, changes in filtration flows, and desorption of heavy-oil components from reservoir rock after its break-up.An acid composition of prolonged-action based on an inorganic acid adduct, a polyol and a surfactant has been developed at the Institute of Petroleum Chemistry, SB RAS. Introduced into the injection well, the composition exerts a prolonged positive effect on the oil recovery in the area of its influence. The increase in oil production rates and decrease in water cuts are accompanied by changes in viscosity of extracted oil and mineral composition of produced water. The appearance of components of a new composition and products of its hydrolysis in the produced fluids suggests the inclusion of still virgin zones, changes in filtration flows, and desorption of heavy-oil components from reservoir rock after its break-up.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83496700","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":"Computer simulation of the synthesis of medical composite materials with the required structural-mechanical characteristics","authors":"A. Tovpinets, V. Leitsin, M. Dmitrieva","doi":"10.1063/1.5132235","DOIUrl":"https://doi.org/10.1063/1.5132235","url":null,"abstract":"A new approach to computer simulation of the synthesis of medical composite materials has been developed to study the determining factors for obtaining a promising class of scaffolds for personalized replacement of bone defects. This class of scaffolds is a dispersed-filled polymer with a biodegradable matrix and a gradient pore structure. Particles of calcium phosphate, magnesium, zinc, boron nitride and biodegradable fibers are considered as dispersed components. This provides antibacterial, medicinal and other properties.A new approach to computer simulation of the synthesis of medical composite materials has been developed to study the determining factors for obtaining a promising class of scaffolds for personalized replacement of bone defects. This class of scaffolds is a dispersed-filled polymer with a biodegradable matrix and a gradient pore structure. Particles of calcium phosphate, magnesium, zinc, boron nitride and biodegradable fibers are considered as dispersed components. This provides antibacterial, medicinal and other properties.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"96 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88406812","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 UHMWPE powder size onto tribological and mechanical properties of composites loaded with functionalized chopped glass fibers","authors":"S. Panin, Qitao Huang, L. Kornienko, D. Buslovich, V. O. Alexenko","doi":"10.1063/1.5132132","DOIUrl":"https://doi.org/10.1063/1.5132132","url":null,"abstract":"Mechanical and tribological properties of UHMWPE composites with the different initial polymer powder size filled with chopped glass fibers (CGF) functionalized with silane-containing KH550 modifier aimed at increase adhesion were studied. It is shown that the various initial powder size at an equivalent molecular weight determines the pattern of glass fiber distribution in the matrix, and, as a consequence, the mechanical and tribotechnical properties of the composites. It was revealed that glass fiber reinforced composite based on fine UHMWPE powder grade GUR-2122 possesses higher tribomechanical properties in contrast with coarse grade GUR-4120 one. For practical antifriction applications the “UHMWPE 2122 + 10 wt. % CGF” composite is recommended loaded with the glass fibers functionalization with the KH550 silane-based industrially manufactured coupling agent.Mechanical and tribological properties of UHMWPE composites with the different initial polymer powder size filled with chopped glass fibers (CGF) functionalized with silane-containing KH550 modifier aimed at increase adhesion were studied. It is shown that the various initial powder size at an equivalent molecular weight determines the pattern of glass fiber distribution in the matrix, and, as a consequence, the mechanical and tribotechnical properties of the composites. It was revealed that glass fiber reinforced composite based on fine UHMWPE powder grade GUR-2122 possesses higher tribomechanical properties in contrast with coarse grade GUR-4120 one. For practical antifriction applications the “UHMWPE 2122 + 10 wt. % CGF” composite is recommended loaded with the glass fibers functionalization with the KH550 silane-based industrially manufactured coupling agent.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88577724","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 the polymetallic samples from Ti-Al and Ti-Cu systems by the electron beam additive manufacturing method","authors":"D. Gurianov, K. Kalashnikov, A. Gusarova, A. Chumaevskii","doi":"10.1063/1.5131993","DOIUrl":"https://doi.org/10.1063/1.5131993","url":null,"abstract":"The structure of polymetallic samples of Ti-Al и Ti-Cu systems obtained by wire-feed electron-beam additive technology in vacuum was studied using optical and scanning electron microscopy and X-ray analysis. The results of research show that during obtaining of polymetals, formation of structure in boundary zones occurs according to corresponding state diagrams. However, due to the small size of the melt bath in relation to metallurgical production, the structure of the finer dispersion structure with greater heterogeneity is formed. In the interaction zone of different metals and alloys it is possible to form both transition structures from solid solutions and intermetallic compounds or mechanical mixtures of initial components and interaction products.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77253720","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":"Indentation and scratch testing of coarse-grained and ultrafine-grained AA6063","authors":"A. Filippov, S. Tarasov","doi":"10.1063/1.5131968","DOIUrl":"https://doi.org/10.1063/1.5131968","url":null,"abstract":"Deformation behavior of coarse- and ultrafine-grained 6063 aluminum alloy ECAPed samples in indentation and scratching has been investigated. The specificity of ultrafine-grained samples was formation of pile-ups on the indentation and scratch groove edges, whose height was greatly higher than those on the coarse-grained samples. Despite the fact that the ultrafine-grained samples had their microhardness numbers higher than those of coarse-grained, the scratch grooves were deeper on the first ones.Deformation behavior of coarse- and ultrafine-grained 6063 aluminum alloy ECAPed samples in indentation and scratching has been investigated. The specificity of ultrafine-grained samples was formation of pile-ups on the indentation and scratch groove edges, whose height was greatly higher than those on the coarse-grained samples. Despite the fact that the ultrafine-grained samples had their microhardness numbers higher than those of coarse-grained, the scratch grooves were deeper on the first ones.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85164489","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}