This study was concerned with the production of carbide dispersion type composite materials by plasma transfer arc welding. The composite materials were produced by introducing different amounts of Cr-carbide and/or Ti-carbide powders in Co-base alloy (Stellite 6). To assess the resistance to wear of the composite materials, rubber wheel abrasion test was performed on surface of the composite materials.The composite materials were consisted of Co-alloy matrix and non-fused carbide. The average hardness of matrix was increased from HV450 to HV850 according to Cr-carbide content of the composite material.Weight loss of composite materials by wear were decreased from 850 mg to 50 mg according to volume fraction of non-fused carbide particles. Especially when mean free path between carbide particles was smaller than size silica sand (wear material), abrasive wear resistance of composite materials was rapidly improved.
{"title":"Effect of TiC-Cr3C2 Particles Content on Abrasive Wear Resistance of Co-Base Overlay Weld Alloy.","authors":"M. Nishida, T. Araki, H. Fujita","doi":"10.2207/QJJWS.11.156","DOIUrl":"https://doi.org/10.2207/QJJWS.11.156","url":null,"abstract":"This study was concerned with the production of carbide dispersion type composite materials by plasma transfer arc welding. The composite materials were produced by introducing different amounts of Cr-carbide and/or Ti-carbide powders in Co-base alloy (Stellite 6). To assess the resistance to wear of the composite materials, rubber wheel abrasion test was performed on surface of the composite materials.The composite materials were consisted of Co-alloy matrix and non-fused carbide. The average hardness of matrix was increased from HV450 to HV850 according to Cr-carbide content of the composite material.Weight loss of composite materials by wear were decreased from 850 mg to 50 mg according to volume fraction of non-fused carbide particles. Especially when mean free path between carbide particles was smaller than size silica sand (wear material), abrasive wear resistance of composite materials was rapidly improved.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132470702","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}
Anodic bonding of glass and Si, which is performed by applying positive voltage of several hundred volt on Si, is well known as Mallory sealing process and has been in use. However, anodic bonding of glass and metal has not been comprehensively investigated and mechanism of the bonding has not been well understood.A fundamental study on anodic bonding of borosilicate glass and metal was carried out. Glass to Mo bonding and glass to Al bonding were successfully made, and glass to 304ss, glass to Ti, glass to Ni and glass to Au bondings were also made but they fractured at low stress level. Bonding test of glass and Mo using the design of experiment was carried out in order to specify dominant bonding parameters. Then, it has become clear that the bonding temperature and the applying voltage should be dominant in the range of bonding temperature of 400°C-600°C, applying voltage of 0 V-350 V, bonding time of 5 min-60 min, bonding pressure of 0.03 MPa-0.7 MPa in Ar atmosphere or in vacuum. Microscopic observations and chemical analysis were performed for glass to Mo bonded structure. The reaction zone between glass and Mo was not identified from the results of SEM and EPMA. Result of ESCA analysis revealed that Na, which was not found around the boundary, was detected in glass near the anode and Mo oxide was detected in glass near the boundary. Basing on the results, it has been considered that metal ions would diffuse into glass substituting for Na' and metal oxide be formed, then glass to metal bonding should be achieved.
玻璃与硅的阳极键合，是通过在硅上施加几百伏的正电压来实现的，被称为马洛里密封工艺，并已得到应用。然而，玻璃与金属的阳极键合还没有得到全面的研究，其键合机理也没有得到很好的了解。对硼硅玻璃与金属的阳极键合进行了基础研究。成功地实现了玻璃- Mo键合和玻璃- Al键合，也成功地实现了玻璃- 304ss键合、玻璃- Ti键合、玻璃- Ni键合和玻璃- Au键合，但它们在低应力水平下断裂。采用实验设计法进行了玻璃与钼的粘结试验，确定了主要的粘结参数。在氩气或真空条件下，焊温为400℃~ 600℃，焊电压为0 V ~ 350 V，焊时间为5 min ~ 60 min，焊压为0.03 MPa ~ 0.7 MPa。对玻璃-钼键合结构进行了显微观察和化学分析。SEM和EPMA均未发现玻璃与Mo之间的反应区。ESCA分析结果表明，在阳极附近的玻璃中检测到边界附近没有发现的Na，在边界附近的玻璃中检测到Mo氧化物。在此基础上，认为金属离子会扩散到玻璃中取代Na'，形成金属氧化物，然后实现玻璃与金属的键合。
{"title":"Study on Glass-metal Bonding by Anodic Bonding.","authors":"M. Toyoda, Y. Fujiya, M. Nayama, Tadashi Yamada","doi":"10.2207/QJJWS.11.208","DOIUrl":"https://doi.org/10.2207/QJJWS.11.208","url":null,"abstract":"Anodic bonding of glass and Si, which is performed by applying positive voltage of several hundred volt on Si, is well known as Mallory sealing process and has been in use. However, anodic bonding of glass and metal has not been comprehensively investigated and mechanism of the bonding has not been well understood.A fundamental study on anodic bonding of borosilicate glass and metal was carried out. Glass to Mo bonding and glass to Al bonding were successfully made, and glass to 304ss, glass to Ti, glass to Ni and glass to Au bondings were also made but they fractured at low stress level. Bonding test of glass and Mo using the design of experiment was carried out in order to specify dominant bonding parameters. Then, it has become clear that the bonding temperature and the applying voltage should be dominant in the range of bonding temperature of 400°C-600°C, applying voltage of 0 V-350 V, bonding time of 5 min-60 min, bonding pressure of 0.03 MPa-0.7 MPa in Ar atmosphere or in vacuum. Microscopic observations and chemical analysis were performed for glass to Mo bonded structure. The reaction zone between glass and Mo was not identified from the results of SEM and EPMA. Result of ESCA analysis revealed that Na, which was not found around the boundary, was detected in glass near the anode and Mo oxide was detected in glass near the boundary. Basing on the results, it has been considered that metal ions would diffuse into glass substituting for Na' and metal oxide be formed, then glass to metal bonding should be achieved.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131122547","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}
Effects of thermal and physical properties of materials on the transient response of temperature to a step change in welding speed were investigated using TIG arc welding and FEM calculation of three-dimensional heat coduction. The materials used in this study were stainless steel, mild steel, aluminum alloy, brass and copper 9 mm in thickness.In TIG arc welding of low heat-conductive materials, large difference in maximum temperature appears in the period between former quasi-state and latter one. On the other hand, high heat-conductive materials indicate large difference in temperature gradient, but a little change in maximum temperature. In addition, the high heat-conductive materials require longer distance or time to be in latter quasi-state. The transient response from former to later quasi-state is characterized by the fraction of maximum temperature and temperature gradient to those at both quasi-states. These experimental results are confirmed by FEM calculations based on three-dimensional heat conduction. It is also clarified that although the maximum temperature mainly depend upon the thermal conductivity and thermal diffusivity, the transient response is dominated only on the thermal diffusivity. Therefore, the high thermal diffusive materials show slower response to a step change in welding speed.
{"title":"Effects of Alloying Elements on the Toughness and Microstructure of HIGH CURRENT DENSITY GAS SHIELDED ARC PROCESS Weld Metals","authors":"S. Satonaka, K. Hari, Y. Matsumoto","doi":"10.2207/QJJWS.11.29","DOIUrl":"https://doi.org/10.2207/QJJWS.11.29","url":null,"abstract":"Effects of thermal and physical properties of materials on the transient response of temperature to a step change in welding speed were investigated using TIG arc welding and FEM calculation of three-dimensional heat coduction. The materials used in this study were stainless steel, mild steel, aluminum alloy, brass and copper 9 mm in thickness.In TIG arc welding of low heat-conductive materials, large difference in maximum temperature appears in the period between former quasi-state and latter one. On the other hand, high heat-conductive materials indicate large difference in temperature gradient, but a little change in maximum temperature. In addition, the high heat-conductive materials require longer distance or time to be in latter quasi-state. The transient response from former to later quasi-state is characterized by the fraction of maximum temperature and temperature gradient to those at both quasi-states. These experimental results are confirmed by FEM calculations based on three-dimensional heat conduction. It is also clarified that although the maximum temperature mainly depend upon the thermal conductivity and thermal diffusivity, the transient response is dominated only on the thermal diffusivity. Therefore, the high thermal diffusive materials show slower response to a step change in welding speed.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"R-34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126541865","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. Kaga, I. Fukuhara, Katsuhiro Fujii, K. Ogawa, T. Baba, Yoshiaki Yamamoto
Impact properties at cryogenic temperature of candicate materials for fusion reactor and their electron beam welded joints are investigated by using instrumented Charpy impact testing apparatus. Material used are aluminum alloys (A7N01, A5083, A6061), JFMS (Japanese Ferritic Martensitic Steel) and two kinds of high manganese steels. Although JFMS is a steel for high temperature use, the impact test is conducted at low tenperature same as the cases of the other materials. Testing results are obtained as follows.1. Base metals and welded joints of aluminum alloys exhibit high absorbed energy at low temperature. Ductility of each base metal and welded joint gradually decreases with decreasing of testing temperature.2. Base metal and welded joint of JFMS exhibit an absorved energy transition temperature at near a room temperature.3. Base metal and welded joint of high manganese)steel A-T (18Mn) exhibit abrupt decreasing of absorbed energy at 77K, but base metal and welded joint of high manganese steel B-T (22Mn-0.2N) exhibit gradual increasing of maximum strength and decreasing of ductility with decreasing of testing temperature.
{"title":"Impact Property at Cryogenic Temperature of Candidate Materials for Fusion Reactor and Their Electron Beam Welded Joint","authors":"S. Kaga, I. Fukuhara, Katsuhiro Fujii, K. Ogawa, T. Baba, Yoshiaki Yamamoto","doi":"10.2207/QJJWS.9.23","DOIUrl":"https://doi.org/10.2207/QJJWS.9.23","url":null,"abstract":"Impact properties at cryogenic temperature of candicate materials for fusion reactor and their electron beam welded joints are investigated by using instrumented Charpy impact testing apparatus. Material used are aluminum alloys (A7N01, A5083, A6061), JFMS (Japanese Ferritic Martensitic Steel) and two kinds of high manganese steels. Although JFMS is a steel for high temperature use, the impact test is conducted at low tenperature same as the cases of the other materials. Testing results are obtained as follows.1. Base metals and welded joints of aluminum alloys exhibit high absorbed energy at low temperature. Ductility of each base metal and welded joint gradually decreases with decreasing of testing temperature.2. Base metal and welded joint of JFMS exhibit an absorved energy transition temperature at near a room temperature.3. Base metal and welded joint of high manganese)steel A-T (18Mn) exhibit abrupt decreasing of absorbed energy at 77K, but base metal and welded joint of high manganese steel B-T (22Mn-0.2N) exhibit gradual increasing of maximum strength and decreasing of ductility with decreasing of testing temperature.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129017417","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}
Sensitization behavior of the delta-ferrite containing stainless steel weld metal was investigated using Type 304 and Type 308 alloys with the carbon content ranging from 0.04% to 0.09%, respective-ly. The weld metals heat treated at 923 K for times varying between 1 sec and 100 hr were tested for intergranular corrosion susceptibility in the acidified copper sulfate solution. The delta ferrite contain-ing weld metal with lower carbon content indicated rapidly healing of sensitization after the short heat treatment, whereas ones with higher carbon content than a critical value behaved as a fully austenitic steel regardless the existence of ferrite without showing the sign of rapid healing. SEM observation revealed that M23C6 precipitated preferentially at the ferrite-austenite boundary and also at the austenite-austenite boundaries although its amount at the latter boundaries was much less than the other in the both weld metals which indicated rapid healing of sensitization and behaved as a fully austenitic steel. A mathematical model is developed for the sensitization of the ferrite containing austenitic stainless steel weld metal. The degree of sensitization calculated using this model has shown a good agreement with the experimental corrosion test results. The calculation also demonstrated that for a given carbon content there exist the critical values for not only the total amount but the thickness of ferrite, above which the weld metal develop the rapid healing of sensitization.
{"title":"Influence of Delta-ferrite on Sensitization of the Austenitic Stainless Steel Weld Metal","authors":"Y. Nakao, K. Nishimoto, M. Ishizaki","doi":"10.2207/QJJWS.9.415","DOIUrl":"https://doi.org/10.2207/QJJWS.9.415","url":null,"abstract":"Sensitization behavior of the delta-ferrite containing stainless steel weld metal was investigated using Type 304 and Type 308 alloys with the carbon content ranging from 0.04% to 0.09%, respective-ly. The weld metals heat treated at 923 K for times varying between 1 sec and 100 hr were tested for intergranular corrosion susceptibility in the acidified copper sulfate solution. The delta ferrite contain-ing weld metal with lower carbon content indicated rapidly healing of sensitization after the short heat treatment, whereas ones with higher carbon content than a critical value behaved as a fully austenitic steel regardless the existence of ferrite without showing the sign of rapid healing. SEM observation revealed that M23C6 precipitated preferentially at the ferrite-austenite boundary and also at the austenite-austenite boundaries although its amount at the latter boundaries was much less than the other in the both weld metals which indicated rapid healing of sensitization and behaved as a fully austenitic steel. A mathematical model is developed for the sensitization of the ferrite containing austenitic stainless steel weld metal. The degree of sensitization calculated using this model has shown a good agreement with the experimental corrosion test results. The calculation also demonstrated that for a given carbon content there exist the critical values for not only the total amount but the thickness of ferrite, above which the weld metal develop the rapid healing of sensitization.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114787729","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}
Susumu Aono, K. Ohmori, Masaki Furuya, T. Takakura
{"title":"Newly developed micro-parallel seam joining equipment and its applications. Micro-parallel seam joining and development of joining equipment(4th Report).","authors":"Susumu Aono, K. Ohmori, Masaki Furuya, T. Takakura","doi":"10.2207/QJJWS.7.425","DOIUrl":"https://doi.org/10.2207/QJJWS.7.425","url":null,"abstract":"","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116591020","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 effect of the nitrogen absorption on the transmission electron microscopic structure of SUS304L austenitic stainless steel weld metal was investigated by varying the nitrogen partial pressure of the Ar-N2 gas mixture welding atmosphere in an atmosphere-controlling chamber. An electron diffraction study suggested that the primary solidification mode of the weld metal alters from ferritic mode to austenitic one with the nitrogen partial pressure and the nitrogen content of weld metal. The austenite frequently adopts a near Kurdjumov-Sachs orientation relationship with the adjacent primary ferrite, while the eutectic ferrite does not adopt the K-S one with the adjacent austenite. The amount of the eutectic ferrite phase increases with the nitrogen partial pressure and the nitrogen content. In the weld metal with no ferrite, precipitation on dislocations and grain boundaries was observed.
{"title":"The Effect of the Nitrogen Absorption on the TEM Structure of SUS304L Austenitic Stainless Steel Weld Metal","authors":"T. Kuwana, H. Kokawa, H. Tsujii","doi":"10.2207/qjjws.4.520","DOIUrl":"https://doi.org/10.2207/qjjws.4.520","url":null,"abstract":"The effect of the nitrogen absorption on the transmission electron microscopic structure of SUS304L austenitic stainless steel weld metal was investigated by varying the nitrogen partial pressure of the Ar-N2 gas mixture welding atmosphere in an atmosphere-controlling chamber. An electron diffraction study suggested that the primary solidification mode of the weld metal alters from ferritic mode to austenitic one with the nitrogen partial pressure and the nitrogen content of weld metal. The austenite frequently adopts a near Kurdjumov-Sachs orientation relationship with the adjacent primary ferrite, while the eutectic ferrite does not adopt the K-S one with the adjacent austenite. The amount of the eutectic ferrite phase increases with the nitrogen partial pressure and the nitrogen content. In the weld metal with no ferrite, precipitation on dislocations and grain boundaries was observed.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124469757","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 : 1983-04-01DOI: 10.2207/QJJWS1943.51.359
Y. Kikuta, T. Araki, M. Yoneda, H. Yoshida, T. Suga
The weld construction using heavy section steel and/or high strength low alloy steel is made by multipass welding. In that case, weld metal is reheated to various temperatures by welding heat of the subsequent pass. This result will lead to both microstructural change and through thickness toughness variation in weld metal.In this work, an investigation was carried out about the reheated zone toughness in weld metal.It is found by this work that, for simple Si-Mn system weld metal, the reheated zone toughness is improved as compared with as-welded touhgness, and increases with the ratio of reheated structure to aswelded structure. This improvement is caused by both the disappearance of columnar structure and the refinement of microstructure.While, for high strength low alloy system weld metal, the reheating shows the complex effect. The reheated zone toughness in this system deteriorates at peak temperature range between 750°C and 950°C, although the remarkable optical microstructural change is not observed.The reheating effect to the toughness of high strength low alloy system weld metal shows the inverse phenomenon as compared with that to the toughness of simple Si-Mn system weld metal.
{"title":"The Reheated Zone Toughness of Multipass Weld Metal (Report 1) : Comparison of Reheated Zone Toughness between Si-Mn System and High Strength Low Alloy System Weld Metals","authors":"Y. Kikuta, T. Araki, M. Yoneda, H. Yoshida, T. Suga","doi":"10.2207/QJJWS1943.51.359","DOIUrl":"https://doi.org/10.2207/QJJWS1943.51.359","url":null,"abstract":"The weld construction using heavy section steel and/or high strength low alloy steel is made by multipass welding. In that case, weld metal is reheated to various temperatures by welding heat of the subsequent pass. This result will lead to both microstructural change and through thickness toughness variation in weld metal.In this work, an investigation was carried out about the reheated zone toughness in weld metal.It is found by this work that, for simple Si-Mn system weld metal, the reheated zone toughness is improved as compared with as-welded touhgness, and increases with the ratio of reheated structure to aswelded structure. This improvement is caused by both the disappearance of columnar structure and the refinement of microstructure.While, for high strength low alloy system weld metal, the reheating shows the complex effect. The reheated zone toughness in this system deteriorates at peak temperature range between 750°C and 950°C, although the remarkable optical microstructural change is not observed.The reheating effect to the toughness of high strength low alloy system weld metal shows the inverse phenomenon as compared with that to the toughness of simple Si-Mn system weld metal.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1983-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122293296","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 : 1982-10-01DOI: 10.2207/QJJWS1943.50.514
Y. Nakao, K. Nishimoto, S. Inoue
{"title":"Kinetics of the Formation of Austenite at Constant Temperature : Study on the Phase Transformation in Welded Joints of Duplex Satinless Steels (Report 1)","authors":"Y. Nakao, K. Nishimoto, S. Inoue","doi":"10.2207/QJJWS1943.50.514","DOIUrl":"https://doi.org/10.2207/QJJWS1943.50.514","url":null,"abstract":"","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"352 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131465172","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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