Pub Date : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_354
Takuya Sato, Taeko Nomoto, K. Kado, G. Yagawa, S. Yoshimura
In this paper we describe a new user-friendly structural design system for pressure vessels, which is based on finite element stress analyses. The basic concept of the developed system is to minimize input data required for the finite element analysis and to perform the analysis quickly. To realize this, the system is equipped with the finite element modeling module based on fuzzy knowledge processing, the input data generation module, the finite element analyzer, the graphic user-interface module for analysis results, and the stress evaluation module. Fundamental performance of the present system is clearly demonstrated through the analysis of a top nozzle.
{"title":"Development of user-friendly structural design system for pressure vessels","authors":"Takuya Sato, Taeko Nomoto, K. Kado, G. Yagawa, S. Yoshimura","doi":"10.1299/JSMEA1993.39.3_354","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_354","url":null,"abstract":"In this paper we describe a new user-friendly structural design system for pressure vessels, which is based on finite element stress analyses. The basic concept of the developed system is to minimize input data required for the finite element analysis and to perform the analysis quickly. To realize this, the system is equipped with the finite element modeling module based on fuzzy knowledge processing, the input data generation module, the finite element analyzer, the graphic user-interface module for analysis results, and the stress evaluation module. Fundamental performance of the present system is clearly demonstrated through the analysis of a top nozzle.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134398773","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_382
M. Arai, T. Ogata, A. Nitta
Structural components operating at high temperatures in power plants are subjected to interaction of thermal fatigue and creep which results in creep-fatigue damage. In evaluating the life of those components, it is important to understand microscopic damage evolution under creep-fatigue conditions. In this study, static creep and creep-fatigue tests with tensile hold-time were conducted on a SUS 304 stainless steel by using a high-temperature fatigue testing machine combined with a scanning electron microscope (SEM), and cavity growth and coalescence behaviors on surface grain boundaries were observed continuously by the SEM. Quantitative analysis of creep cavity growth based on the observations was made for comparison with theoretical growth models. As a result, it was found that cavities nucleate at random and grow preferentially on grain boundaries in a direction almost normal to the stress axis. Under creep condition, the cavities grew monotonously on grain boundaries while remaining an elliptical shape. On the other hand, under creep-fatigue conditions, the cavities grew due to the effect of the local strain distribution around the grain boundary due to cyclic loading and microcracks of one grain-boundary length were formed by coalescence of the cavities. Also, cavity nucleation and growth rates under the creep-fatigue condition were more rapid than those under the static creep condition and the constrained cavity growth model coincided well with the experimental data for creep.
{"title":"Continuous Observation of Cavity Growth and Coalescence by Creep-Fatigue Tests in SEM","authors":"M. Arai, T. Ogata, A. Nitta","doi":"10.1299/JSMEA1993.39.3_382","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_382","url":null,"abstract":"Structural components operating at high temperatures in power plants are subjected to interaction of thermal fatigue and creep which results in creep-fatigue damage. In evaluating the life of those components, it is important to understand microscopic damage evolution under creep-fatigue conditions. In this study, static creep and creep-fatigue tests with tensile hold-time were conducted on a SUS 304 stainless steel by using a high-temperature fatigue testing machine combined with a scanning electron microscope (SEM), and cavity growth and coalescence behaviors on surface grain boundaries were observed continuously by the SEM. Quantitative analysis of creep cavity growth based on the observations was made for comparison with theoretical growth models. As a result, it was found that cavities nucleate at random and grow preferentially on grain boundaries in a direction almost normal to the stress axis. Under creep condition, the cavities grew monotonously on grain boundaries while remaining an elliptical shape. On the other hand, under creep-fatigue conditions, the cavities grew due to the effect of the local strain distribution around the grain boundary due to cyclic loading and microcracks of one grain-boundary length were formed by coalescence of the cavities. Also, cavity nucleation and growth rates under the creep-fatigue condition were more rapid than those under the static creep condition and the constrained cavity growth model coincided well with the experimental data for creep.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134409740","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_321
N. Yanagida, O. Watanabe
Molecular dynamics simulation was performed on bcc α-iron having two different lattice orientations which both included a primary slip direction (111) in the plane of applied tensile stress. Cracks on the (100) and on the (011) plane with crack growthedge direction [011] were studied. For cracks on the (100) plane, no nucleation of dislocations was observed, and the cracks propagated in both low- and high-temperature environments. For those on the (011) plane, brittle fractures without nucleation of dislocations occurred at low-temperature, but at high-temperature nucleation of [111] dislocation from the crack tip was observed. Local stress on the cleavage plane and on the slip plane are discussed from the viewpoint of the fracture mechanism.
{"title":"Molecular Dynamics Simulation of Effects of Lattice Orientation on Crack Propagation in Alpha-Iron when the Primary Slip Direction is in the Plane of Tensile Stress","authors":"N. Yanagida, O. Watanabe","doi":"10.1299/JSMEA1993.39.3_321","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_321","url":null,"abstract":"Molecular dynamics simulation was performed on bcc α-iron having two different lattice orientations which both included a primary slip direction (111) in the plane of applied tensile stress. Cracks on the (100) and on the (011) plane with crack growthedge direction [011] were studied. For cracks on the (100) plane, no nucleation of dislocations was observed, and the cracks propagated in both low- and high-temperature environments. For those on the (011) plane, brittle fractures without nucleation of dislocations occurred at low-temperature, but at high-temperature nucleation of [111] dislocation from the crack tip was observed. Local stress on the cleavage plane and on the slip plane are discussed from the viewpoint of the fracture mechanism.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134569160","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_337
H. Koguchi
It is known that intrinsic mechanical stress exists in a general free surface or interface, because of surface atomic structure changes relative to the bulk. We present an analysis of using the interrelationship between surface stresses, free surface and volume stress deduced in our previous paper. The surface stresses are closely related to the surface energy and surface geometry (mean curvature) of materials. In the present paper, an elastic contact problem in which an axisymmetric elastic body is pressed into an elastic half-region coated with a thin elastic film is analyzed using the three-dimensional theory of elasticity. In this analysis, the relevant dimensionless parameter, called the elastic capillary number, which is a function of surface energy, elastic modulus and the film thickness, is introduced. It is shown that the elastic modulus of the thin film apparently increases and the bulk stress also increases when the surface stresses are taken into account.
{"title":"Stress Analysis for Nano-Scale Elastic Materials : Elastic Contact Problems Considering Surface Stresses","authors":"H. Koguchi","doi":"10.1299/JSMEA1993.39.3_337","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_337","url":null,"abstract":"It is known that intrinsic mechanical stress exists in a general free surface or interface, because of surface atomic structure changes relative to the bulk. We present an analysis of using the interrelationship between surface stresses, free surface and volume stress deduced in our previous paper. The surface stresses are closely related to the surface energy and surface geometry (mean curvature) of materials. In the present paper, an elastic contact problem in which an axisymmetric elastic body is pressed into an elastic half-region coated with a thin elastic film is analyzed using the three-dimensional theory of elasticity. In this analysis, the relevant dimensionless parameter, called the elastic capillary number, which is a function of surface energy, elastic modulus and the film thickness, is introduced. It is shown that the elastic modulus of the thin film apparently increases and the bulk stress also increases when the surface stresses are taken into account.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126090983","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_375
S. Murakami, T. Umeda, H. Takizawa, M. Itoh
A systematic method of spall damage analysis was developed on the basis of damage mechanics. By use of a scalar damage variable, the damage evolution equation of Lemaitre et al. and the viscoplastic constitutive equation of Perzyna modified for damaged materials were incorporated into the commercial finite difference program MANJUSRI-3 D for nonlinear dynamic analysis. The spall damage process, and stress wave propagation and temperature histories were analyzed for plate impact of OFHC copper disc targets. The computational results for the stress history and the particle velocity at the rear surface of the target plates were compared with the corresponding experimental results.
{"title":"Application of damage mechanics to the analysis of spall damage","authors":"S. Murakami, T. Umeda, H. Takizawa, M. Itoh","doi":"10.1299/JSMEA1993.39.3_375","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_375","url":null,"abstract":"A systematic method of spall damage analysis was developed on the basis of damage mechanics. By use of a scalar damage variable, the damage evolution equation of Lemaitre et al. and the viscoplastic constitutive equation of Perzyna modified for damaged materials were incorporated into the commercial finite difference program MANJUSRI-3 D for nonlinear dynamic analysis. The spall damage process, and stress wave propagation and temperature histories were analyzed for plate impact of OFHC copper disc targets. The computational results for the stress history and the particle velocity at the rear surface of the target plates were compared with the corresponding experimental results.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115279324","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_407
M. Shimoda, H. Azegami, T. Sakurai
We describe numerical analysis methods for multiobjective shape optimization of linear elastic structures. As an example, we consider a multiloading mean compliance minimization problem with a volume constraint. The methods presented here are based on the traction method, in which the speed field representing the domain variation is analyzed. A weighted lp norm method with four types of norm is employed to scalarize the multiobjective functionals. The shape gradient functions for each scalarized objective functional are obtained using the Lagrange multiplier method. A general-purpose finite element code is used to perform the numerical analyses. Numerical analysis results for a multiply connected plate problem and a solid structure problem under multiloading conditions are presented to demonstrate the validity of the traction method in obtaining Pareto optimal solutions.
{"title":"Multiobjective Shape Optimization of Linear Elastic Structures Considering Multiple Loading Conditions (Dealing with Mean Compliance Minimization problems)","authors":"M. Shimoda, H. Azegami, T. Sakurai","doi":"10.1299/JSMEA1993.39.3_407","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_407","url":null,"abstract":"We describe numerical analysis methods for multiobjective shape optimization of linear elastic structures. As an example, we consider a multiloading mean compliance minimization problem with a volume constraint. The methods presented here are based on the traction method, in which the speed field representing the domain variation is analyzed. A weighted lp norm method with four types of norm is employed to scalarize the multiobjective functionals. The shape gradient functions for each scalarized objective functional are obtained using the Lagrange multiplier method. A general-purpose finite element code is used to perform the numerical analyses. Numerical analysis results for a multiply connected plate problem and a solid structure problem under multiloading conditions are presented to demonstrate the validity of the traction method in obtaining Pareto optimal solutions.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126556712","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_330
E. Tanaka, Tohru Takahashi, S. Murakami
A three-dimensional transversely isotropic constitutive model of cardiac muscle is proposed. Stress in the cardiac muscle is first divided into the sum of passive and active parts. The passive part is represented by a strain energy, density function of the exponential type, while the active part is formulated by introducing internal variables describing the activities and the sarcomere length. The evolution equations of the internal variables are established by taking account of excitation-contraction coupling. Comparison of the simulation results with those of experiments in the literature shows that the present model can describe qualitatively the mechanical properties of cardiac muscle.
{"title":"A mechanical model of cardiac muscle taking account of excitation-contraction coupling","authors":"E. Tanaka, Tohru Takahashi, S. Murakami","doi":"10.1299/JSMEA1993.39.3_330","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_330","url":null,"abstract":"A three-dimensional transversely isotropic constitutive model of cardiac muscle is proposed. Stress in the cardiac muscle is first divided into the sum of passive and active parts. The passive part is represented by a strain energy, density function of the exponential type, while the active part is formulated by introducing internal variables describing the activities and the sarcomere length. The evolution equations of the internal variables are established by taking account of excitation-contraction coupling. Comparison of the simulation results with those of experiments in the literature shows that the present model can describe qualitatively the mechanical properties of cardiac muscle.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127541603","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_367
H. Kisu
It has been found that the boundary integral equations for steady problems such as those of potential, elasticity, fluid mechanics and so on can be regularized by introducing relative quantities of field functions. We describe that fundamental integral equations for unsteady heat conduction problems can also be regularized by applying the same techniques. The regularized integral equations with relative quantity are obtained by superposing a particular solution under the condition of time-independent uniform potential upon the conventional ones. This approach has made it possible to derive the integral equation of potential gradient on a surface point, which has not been given up to now in the conventional formulation due to hyper-singularity. Through two- and three-dimensional numerical investigations, it is verified that the present integral equations give accurate numerical results everywhere over the domain and that they are valid and effective.
{"title":"Regularization of the Integral Equations for Unsteady Heat Conduction Problems","authors":"H. Kisu","doi":"10.1299/JSMEA1993.39.3_367","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_367","url":null,"abstract":"It has been found that the boundary integral equations for steady problems such as those of potential, elasticity, fluid mechanics and so on can be regularized by introducing relative quantities of field functions. We describe that fundamental integral equations for unsteady heat conduction problems can also be regularized by applying the same techniques. The regularized integral equations with relative quantity are obtained by superposing a particular solution under the condition of time-independent uniform potential upon the conventional ones. This approach has made it possible to derive the integral equation of potential gradient on a surface point, which has not been given up to now in the conventional formulation due to hyper-singularity. Through two- and three-dimensional numerical investigations, it is verified that the present integral equations give accurate numerical results everywhere over the domain and that they are valid and effective.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121150145","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_313
A. Yasukawa
Calculations of SiO 2 static-fatigue strength are used to show that the strength- degradation behavior of the material under the influence of the ambient atmosphere can be analyzed using an interatomic potential which is based on the Tersoff potential but extended to take charge transfer effects into account. The force-elongation curves of the Si-O interatomic bonds of the SiO2 are calculated with and without H 2 O in the atmosphere. Based on these curves, crack propagation behavior is analyzed, and calculated results are shown to correspond well with experimental results. Moreover, the calculated values of the strength decrease caused by the H 2 O also show fair agreement with the experimental values.
{"title":"Using An Extended Tersoff Interatomic Potential to Analyze The Static-Fatigue Strength of SiO2 under Atmospheric Influence","authors":"A. Yasukawa","doi":"10.1299/JSMEA1993.39.3_313","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_313","url":null,"abstract":"Calculations of SiO 2 static-fatigue strength are used to show that the strength- degradation behavior of the material under the influence of the ambient atmosphere can be analyzed using an interatomic potential which is based on the Tersoff potential but extended to take charge transfer effects into account. The force-elongation curves of the Si-O interatomic bonds of the SiO2 are calculated with and without H 2 O in the atmosphere. Based on these curves, crack propagation behavior is analyzed, and calculated results are shown to correspond well with experimental results. Moreover, the calculated values of the strength decrease caused by the H 2 O also show fair agreement with the experimental values.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"210 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122593681","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 : 1996-07-15DOI: 10.1299/JSMEA1993.39.3_389
K. Tohgo, T. Chou
An incremental theory is developed to describe the elastic-plastic behavior and damage behavior of particulate-reinforced composites, based on Eshelby's (1957) solution for an ellipsoidal inclusion and Mori and Tanaka's (1973) concept of average stress/strain for a finite concentration of particles. In the composites containing hard spherical particles in a ductile matrix, debonding of the particle-matrix interface is a significant damage process, since the accumulation of the debonding damage affects the deformation and strength of the composites. The debonding damage is assumed to be controlled by the stress of the particle and the statistical behavior of the particle - matrix interfacial strength. During debonding, the stress of the particle is released and the site of the particle is regarded as a void, resulting in a void concentration which increases with deformation. The theory describes not only the reinforcing effect due to the intact particles but also the weakening effect due to the damaged particles. Analysis of the stress-strain response under uniaxial tension has been carried out on the particulate-reinforcer composite based on the present theory. The influence of the damage on the stress-strain relation of the composite is very strong and depends on the statistical properties of the particle-matrix interfacial strength.
{"title":"Incremental Theory of Particulate-Reinforced Composites Including Debonding Damage","authors":"K. Tohgo, T. Chou","doi":"10.1299/JSMEA1993.39.3_389","DOIUrl":"https://doi.org/10.1299/JSMEA1993.39.3_389","url":null,"abstract":"An incremental theory is developed to describe the elastic-plastic behavior and damage behavior of particulate-reinforced composites, based on Eshelby's (1957) solution for an ellipsoidal inclusion and Mori and Tanaka's (1973) concept of average stress/strain for a finite concentration of particles. In the composites containing hard spherical particles in a ductile matrix, debonding of the particle-matrix interface is a significant damage process, since the accumulation of the debonding damage affects the deformation and strength of the composites. The debonding damage is assumed to be controlled by the stress of the particle and the statistical behavior of the particle - matrix interfacial strength. During debonding, the stress of the particle is released and the site of the particle is regarded as a void, resulting in a void concentration which increases with deformation. The theory describes not only the reinforcing effect due to the intact particles but also the weakening effect due to the damaged particles. Analysis of the stress-strain response under uniaxial tension has been carried out on the particulate-reinforcer composite based on the present theory. The influence of the damage on the stress-strain relation of the composite is very strong and depends on the statistical properties of the particle-matrix interfacial strength.","PeriodicalId":143127,"journal":{"name":"JSME international journal. Series A, mechanics and material engineering","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128373116","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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