Thermal residual stress (TRS) created in metal matrix composite influences the mechanical properties of composites. In this paper, we present the TRS-modulated tensile properties of continuous SiC fiber reinforced titanium (SiC/Ti) composite. The magnitude and distribution of TRS inside SiC/Ti were evaluated by using a simple 1-D beam model considering fiber-matrix structure and then a full 3-D FEM model. The bending of the SiC/Ti specimen resulting from the asymmetrical fiber placements was used as a measure to verify the pertinence of the mechanical models. A 3-D FEM simulation accounting all TRS information gives a good prediction of the composite’s tensile properties.
{"title":"Residual Stress and Its Effect on Yielding in SiC/Ti Plate","authors":"F. Zhou, R. Hashimoto, A. Ogawa, Y. Sofue","doi":"10.1299/JSMEA.49.25","DOIUrl":"https://doi.org/10.1299/JSMEA.49.25","url":null,"abstract":"Thermal residual stress (TRS) created in metal matrix composite influences the mechanical properties of composites. In this paper, we present the TRS-modulated tensile properties of continuous SiC fiber reinforced titanium (SiC/Ti) composite. The magnitude and distribution of TRS inside SiC/Ti were evaluated by using a simple 1-D beam model considering fiber-matrix structure and then a full 3-D FEM model. The bending of the SiC/Ti specimen resulting from the asymmetrical fiber placements was used as a measure to verify the pertinence of the mechanical models. A 3-D FEM simulation accounting all TRS information gives a good prediction of the composite’s tensile properties.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115098864","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}
We have developed a microprobe that achieves low contact resistance under low contact force only for gold pads. However, in the case of Al pads, an oxide layer formed on the aluminum pad surface obstructs stable contacting, so higher contact force with a strong probe is required. The present study attempts to enhance the strength of the probe material by improving its mechanical properties. It is said that grain downsizing, functionally alloying, or impurity addition can increase material strength. Our study has adopted impurity addition to the electroforming bath because the process can be controlled. Thus, high-strength electroformed Ni has successfully been obtained. Improved Ni has a high Vickers hardness of Hv600 compared with Hv450 for conventional nickel, and a high Young’s modulus of E=200GPa compared with E=150GPa for conventional nickel.
{"title":"Investigation of High-Strength Electroformed Ni for Microprobes","authors":"T. Kimura, N. Arita, H. Fukinbara, T. Hattori","doi":"10.1299/JSMEA.49.79","DOIUrl":"https://doi.org/10.1299/JSMEA.49.79","url":null,"abstract":"We have developed a microprobe that achieves low contact resistance under low contact force only for gold pads. However, in the case of Al pads, an oxide layer formed on the aluminum pad surface obstructs stable contacting, so higher contact force with a strong probe is required. The present study attempts to enhance the strength of the probe material by improving its mechanical properties. It is said that grain downsizing, functionally alloying, or impurity addition can increase material strength. Our study has adopted impurity addition to the electroforming bath because the process can be controlled. Thus, high-strength electroformed Ni has successfully been obtained. Improved Ni has a high Vickers hardness of Hv600 compared with Hv450 for conventional nickel, and a high Young’s modulus of E=200GPa compared with E=150GPa for conventional nickel.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114321307","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}
The composite material was fabricated using alumina sludge, industry waste, and aluminum powder by spark plasma sintering (SPS). Sludge of industry waste was treated to change the α alumina crystal structure at temperature 1 573 K for 2 hours. The bending strength of the composite materials was investigated by changing the volume fraction of sludge 0 – 6% and forming conditions. As a result, it was found that the sludge content mainly affected on the bending strength. The bending strength showed the highest value at 2% sludge content. From the observation of crack propagation using optical microscope, it became clear that the sludge existed as agglomerated powder in the composite material, and this sludge prevented the crack to propagate.
{"title":"Fabrication of Composite Material Using Alumina Agglomerated Sludge and Aluminum Powder by Spark Plasma Sintering","authors":"I. Fukumoto, S. Mekaru, S. Shibata, K. Nakayama","doi":"10.1299/JSMEA.49.91","DOIUrl":"https://doi.org/10.1299/JSMEA.49.91","url":null,"abstract":"The composite material was fabricated using alumina sludge, industry waste, and aluminum powder by spark plasma sintering (SPS). Sludge of industry waste was treated to change the α alumina crystal structure at temperature 1 573 K for 2 hours. The bending strength of the composite materials was investigated by changing the volume fraction of sludge 0 – 6% and forming conditions. As a result, it was found that the sludge content mainly affected on the bending strength. The bending strength showed the highest value at 2% sludge content. From the observation of crack propagation using optical microscope, it became clear that the sludge existed as agglomerated powder in the composite material, and this sludge prevented the crack to propagate.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114541621","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}
By folding a thin flat sheet with periodically set slits or punched out portions into the third dimension, ultra-lightweight strong and functional core models are newly devised. The basic idea of this modeling arises from the application of origami technique to engineering. Based on the space filling models, fundamental flat cores and skew type sponge cores have been newly developed. By applying these models, such modified core models as curved cores and 3D honeycomb core are newly devised.
{"title":"Development of Newly Designed Ultra-Light Core Structures","authors":"T. Nojima, Kazuya Saito","doi":"10.1299/JSMEA.49.38","DOIUrl":"https://doi.org/10.1299/JSMEA.49.38","url":null,"abstract":"By folding a thin flat sheet with periodically set slits or punched out portions into the third dimension, ultra-lightweight strong and functional core models are newly devised. The basic idea of this modeling arises from the application of origami technique to engineering. Based on the space filling models, fundamental flat cores and skew type sponge cores have been newly developed. By applying these models, such modified core models as curved cores and 3D honeycomb core are newly devised.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130807917","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}
This paper addresses a viscoplastic constitutive model that allows a consistent way of modeling positive and negative rate sensitivities of flow stress, which is associated with dynamic strain aging occurring in a certain regime of loading rates and temperatures. Based on the concept of continuum mechanics, a phenomenological constitutive model includes the use of a yield surface within the framework of unified viscoplastic constitutive equations. An extension of modeling capability to negative rate sensitivity of flow stress is accomplished through a rate-dependent format of nonlinear kinematic hardening rule that causes the back stress to be rate-dependent. The negative rate sensitivity of the back stress enable to predict the influence of prior strain rate on relaxation behavior, which means that the relaxed stress of the fastest prior strain rate has the smallest magnitude at the end of relaxation period.
{"title":"Unified Constitutive Equations of Viscoplastic Deformation: Development and Capabilities","authors":"K.-C. Ho","doi":"10.1299/JSMEA.49.138","DOIUrl":"https://doi.org/10.1299/JSMEA.49.138","url":null,"abstract":"This paper addresses a viscoplastic constitutive model that allows a consistent way of modeling positive and negative rate sensitivities of flow stress, which is associated with dynamic strain aging occurring in a certain regime of loading rates and temperatures. Based on the concept of continuum mechanics, a phenomenological constitutive model includes the use of a yield surface within the framework of unified viscoplastic constitutive equations. An extension of modeling capability to negative rate sensitivity of flow stress is accomplished through a rate-dependent format of nonlinear kinematic hardening rule that causes the back stress to be rate-dependent. The negative rate sensitivity of the back stress enable to predict the influence of prior strain rate on relaxation behavior, which means that the relaxed stress of the fastest prior strain rate has the smallest magnitude at the end of relaxation period.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114076490","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}
In cementless total hip replacement, initial stability of the femoral component is important in the long term fixation of the femoral stem. Initial stability is closely related to the relative displacement between the prosthesis and the cancellous bone of the proximal femur. After implantation of the prosthesis, the surrounding bone is partially shielded from load carrying and starts to resorb. Stress shielding causes the loss of the proximal bone. The stress distribution of femur must be assessed to predict stress shielding. The initial stability and the stress shielding were investigated for two loading conditions approximating a single leg stance and stair climbing. Two types of stems involving a distal filling and a distal short stem were studied by the finite element method to investigate the biomechanical distal filling effects. The distal short stem produced less stress shielding at the proximal bone than the distal filling stem, while both types of stems seemed to satisfy the initial stability requirement.
{"title":"Biomechanical Study on Distal Filling Effects in Cementless Total Hip Replacement","authors":"S. Chae, Jun hyoung Lee, H. Choi","doi":"10.1299/JSMEA.49.147","DOIUrl":"https://doi.org/10.1299/JSMEA.49.147","url":null,"abstract":"In cementless total hip replacement, initial stability of the femoral component is important in the long term fixation of the femoral stem. Initial stability is closely related to the relative displacement between the prosthesis and the cancellous bone of the proximal femur. After implantation of the prosthesis, the surrounding bone is partially shielded from load carrying and starts to resorb. Stress shielding causes the loss of the proximal bone. The stress distribution of femur must be assessed to predict stress shielding. The initial stability and the stress shielding were investigated for two loading conditions approximating a single leg stance and stair climbing. Two types of stems involving a distal filling and a distal short stem were studied by the finite element method to investigate the biomechanical distal filling effects. The distal short stem produced less stress shielding at the proximal bone than the distal filling stem, while both types of stems seemed to satisfy the initial stability requirement.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132131430","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}
S. Wakayama, Yasuhiro Suzuki, T. Oshima, Satoshi Kobayashi
Microfracture process of 3 mol% yttria stabilized zirconia (3Y-TZP) for artificial joints was evaluated using the acoustic emission technique. In order to investigate the e ff ects of environment and strain rate on the microfracture process, four point bending tests were carried out in air and physiological saline (P.S.) at various loading rates. From the results of AE behavior, rapid AE increasing point was observed before the final unstable fracture. It was suggested from the previous work that the AE increasing point corresponds to the maincrack formation. The critical stress for maincrack formation, σ C , was determined from the bending stress at the AE increasing point. The critical stress as well as bending strength, σ B , decreased in physiological saline. In particular, the decrease in critical stress was remarkable. It was then understood that stress corrosion cracking (SCC) by water in physiological saline a ff ected maincrack formation rather than the final fracture. Consequently, it was suggested that the evaluation of σ C is essential for the reliability assessment of bioceramics.
{"title":"AE Monitoring of Microdamages in Bioceramics for Artificial Joints under Simulated Body Environment","authors":"S. Wakayama, Yasuhiro Suzuki, T. Oshima, Satoshi Kobayashi","doi":"10.1299/JSMEA.49.11","DOIUrl":"https://doi.org/10.1299/JSMEA.49.11","url":null,"abstract":"Microfracture process of 3 mol% yttria stabilized zirconia (3Y-TZP) for artificial joints was evaluated using the acoustic emission technique. In order to investigate the e ff ects of environment and strain rate on the microfracture process, four point bending tests were carried out in air and physiological saline (P.S.) at various loading rates. From the results of AE behavior, rapid AE increasing point was observed before the final unstable fracture. It was suggested from the previous work that the AE increasing point corresponds to the maincrack formation. The critical stress for maincrack formation, σ C , was determined from the bending stress at the AE increasing point. The critical stress as well as bending strength, σ B , decreased in physiological saline. In particular, the decrease in critical stress was remarkable. It was then understood that stress corrosion cracking (SCC) by water in physiological saline a ff ected maincrack formation rather than the final fracture. Consequently, it was suggested that the evaluation of σ C is essential for the reliability assessment of bioceramics.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125269333","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}
R. Murakami, Yun-Hae Kim, Kazushi Kimura, D. Yonekura, Do-Hoon Shin
Scratch tests and pin-on-disk wear tests were performed to clarify the cracking and delaminating behavior of CrN coatings. The CrN films were coated onto an aluminum alloy substrate, JIS A2024, by an arc ion plating method. Eight types of single-layered coating and multilayered coatings were prepared by changing the bias voltage during the deposition. LCI and LCII values were not improved by increasing the number of layers. The critical loads of the single-layered coatings decreased with increasing the bias voltage. It appears that, for the multilayered coatings, the combination of bias voltages influenced the critical loads. The critical loads strongly depended on dynamic hardness and Young’s modulus. In particular, the critical loads of the multilayered coatings were influenced by the properties of the intermediate and bottom layers as well as the surface roughness, hardness and Young’s modulus of the top layer. The large film delamination for single-layered coatings deposited using a high bias voltage occurred during pin-on-disk wear tests even though the critical loads of the single-layered coatings were higher than those of the multilayered coatings. If the brittle top layer could be broken and delaminated by the sliding contact, the ductile bottom layer coated under a bias voltage of 0V could endure the complete delamination of film.
{"title":"Evaluation of Adhesive Behaviors of Chromium Nitride Coating Films Produced by Arc Ion Plating Method","authors":"R. Murakami, Yun-Hae Kim, Kazushi Kimura, D. Yonekura, Do-Hoon Shin","doi":"10.1299/JSMEA.49.123","DOIUrl":"https://doi.org/10.1299/JSMEA.49.123","url":null,"abstract":"Scratch tests and pin-on-disk wear tests were performed to clarify the cracking and delaminating behavior of CrN coatings. The CrN films were coated onto an aluminum alloy substrate, JIS A2024, by an arc ion plating method. Eight types of single-layered coating and multilayered coatings were prepared by changing the bias voltage during the deposition. LCI and LCII values were not improved by increasing the number of layers. The critical loads of the single-layered coatings decreased with increasing the bias voltage. It appears that, for the multilayered coatings, the combination of bias voltages influenced the critical loads. The critical loads strongly depended on dynamic hardness and Young’s modulus. In particular, the critical loads of the multilayered coatings were influenced by the properties of the intermediate and bottom layers as well as the surface roughness, hardness and Young’s modulus of the top layer. The large film delamination for single-layered coatings deposited using a high bias voltage occurred during pin-on-disk wear tests even though the critical loads of the single-layered coatings were higher than those of the multilayered coatings. If the brittle top layer could be broken and delaminated by the sliding contact, the ductile bottom layer coated under a bias voltage of 0V could endure the complete delamination of film.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"239 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121870682","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}
Anti-symmetrical laminate composites exhibit a coupling effect between tensile stress and twisting deformation, and are very attractive as blade materials for aircraft engines. Blades made of anti-symmetrical laminate composites can automatically adjust their stagger angle to a better aerodynamic configuration with changing rotational speed. Thus, the aerodynamic efficiency and stability of aircraft engines can be greatly improved. In this study, the coupled deformation properties of anti-symmetrical laminate composites were evaluated with tensile tests. Two kinds of specimens fabricated from carbon/epoxy laminate composites with different anti-symmetrical stacking sequences were tested. On the basis of the tensile-test results, the anti-symmetrical laminate composites were then used as blade materials. The coupled deformation of the test blades at high rotational speed was evaluated by spin tests and FEM analyses. It was demonstrated that test blades twisted about 4° at 10000rpm.
{"title":"Coupled Deformation Properties of Anti-Symmetrical Laminate Composites","authors":"M. Hojo, R. Hashimoto, A. Ogawa","doi":"10.1299/JSMEA.49.43","DOIUrl":"https://doi.org/10.1299/JSMEA.49.43","url":null,"abstract":"Anti-symmetrical laminate composites exhibit a coupling effect between tensile stress and twisting deformation, and are very attractive as blade materials for aircraft engines. Blades made of anti-symmetrical laminate composites can automatically adjust their stagger angle to a better aerodynamic configuration with changing rotational speed. Thus, the aerodynamic efficiency and stability of aircraft engines can be greatly improved. In this study, the coupled deformation properties of anti-symmetrical laminate composites were evaluated with tensile tests. Two kinds of specimens fabricated from carbon/epoxy laminate composites with different anti-symmetrical stacking sequences were tested. On the basis of the tensile-test results, the anti-symmetrical laminate composites were then used as blade materials. The coupled deformation of the test blades at high rotational speed was evaluated by spin tests and FEM analyses. It was demonstrated that test blades twisted about 4° at 10000rpm.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":" 48","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120830799","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}
This paper describes development of high performance CFRP/metal active laminates mainly by investigating the kind and thickness of the metal. Various types of the laminates were made by hot-pressing of an aluminum, aluminum alloys, a stainless steel and a titanium for the metal layer as a high CTE material, a unidirectional CFRP prepreg as a low CTE/electric resistance heating material, a unidirectional KFRP prepreg as a low CTE/insulating material. The aluminum and its alloy type laminates have almost the same and the highest room temperature curvatures and they linearly change with increasing temperature up to their fabrication temperature. The curvature of the stainless steel type jumps from one to another around its fabrication temperature, whereas the titanium type causes a double curvature and its change becomes complicated. The output force of the stainless steel type attains the highest of the three under the same thickness. The aluminum type successfully increased its output force by increasing its thickness and using its alloys. The electric resistance of the CFRP layer can be used to monitor the temperature, that is, the curvature of the active laminate because the curvature is a function of temperature.
{"title":"Development of High Performance CFRP/Metal Active Laminates","authors":"H. Asanuma, O. Haga, M. Imori","doi":"10.1299/JSMEA.49.32","DOIUrl":"https://doi.org/10.1299/JSMEA.49.32","url":null,"abstract":"This paper describes development of high performance CFRP/metal active laminates mainly by investigating the kind and thickness of the metal. Various types of the laminates were made by hot-pressing of an aluminum, aluminum alloys, a stainless steel and a titanium for the metal layer as a high CTE material, a unidirectional CFRP prepreg as a low CTE/electric resistance heating material, a unidirectional KFRP prepreg as a low CTE/insulating material. The aluminum and its alloy type laminates have almost the same and the highest room temperature curvatures and they linearly change with increasing temperature up to their fabrication temperature. The curvature of the stainless steel type jumps from one to another around its fabrication temperature, whereas the titanium type causes a double curvature and its change becomes complicated. The output force of the stainless steel type attains the highest of the three under the same thickness. The aluminum type successfully increased its output force by increasing its thickness and using its alloys. The electric resistance of the CFRP layer can be used to monitor the temperature, that is, the curvature of the active laminate because the curvature is a function of temperature.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121001215","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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