Yan Zhang, Qin Ni, Zhen Ouyang, Haowen Bian, Tianqi Bu
{"title":"Controllable vertical and radial corrosion by step flow fields for fabricating large aspect ratio micro-cone arrays in through-mask electrochemical micromachining","authors":"Yan Zhang, Qin Ni, Zhen Ouyang, Haowen Bian, Tianqi Bu","doi":"10.1016/j.jmatprotec.2024.118664","DOIUrl":"10.1016/j.jmatprotec.2024.118664","url":null,"abstract":"<div><div>Ionic liquid electrospray thrusters (ILET) have the advantages of high efficiency, small size and low power consumption, and are widely used in micro and nanosatellite propulsion systems. As the core component of the electrospray thruster, the height and tip diameter of the micro-cone emitter array determine the performance of the thrust system. To increase the height of the micro-cone emitter, a through-mask electrochemical micromachining (TMEMM) processing method was proposed in this study. The eddy current generated under the mask in the low-speed flow field was innovatively used to make the gas and solid products gather on the processing side wall to form a product film, which effectively reduced the radial corrosion rate and achieved higher longitudinal processing. In sequence, high-speed flow field was applied to achieve high radial corrosion rate, high contour accuracy and high surface quality. By switching the low-speed flow field and the high-speed flow field, the vertical and radial corrosion rates were controlled. Finally, a microcone array with a height of 256.2 μm and a tip diameter of 20.3 μm was fabricated.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118664"},"PeriodicalIF":6.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhiyuan Jia , Zhandong Wang , Mingzhi Chen , Kai Zhao , Guifang Sun , En-Hou Han
{"title":"Tailoring microstructural evolution in laser deposited nickel-aluminum bronze alloy by controlling water cooling condition","authors":"Zhiyuan Jia , Zhandong Wang , Mingzhi Chen , Kai Zhao , Guifang Sun , En-Hou Han","doi":"10.1016/j.jmatprotec.2024.118659","DOIUrl":"10.1016/j.jmatprotec.2024.118659","url":null,"abstract":"<div><div>Inspired by the application requirements of underwater in-situ repair of nickel-aluminum bronze (NAB), the study proposes whether the water-cooling conditions are conducive to forming an appropriate cooling rate during the repair process to prevent the formation of coarse κ phases. The appropriate cooling rates of underwater repair has been preliminarily verified through numerical simulation. Then onshore laser direct metal deposition (DMD) and underwater laser direct metal deposition (UDMD) technologies are employed to the repair of the trapezoidal grooves on NAB substrates. The experimental results show that the rapid cooling rates during UDMD result in a unique microstructure. Compared to DMD repaired samples, the width of the interlayer heat-affected zone and the average size of nano κ<sub>Ⅱ</sub> phase are reduced, no κ<sub>Ⅳ</sub> precipitates were observed in any of the repaired samples. An interesting finding is that the κ<sub>Ⅲ</sub> phases are dispersively precipitated in the matrix. Both the tensile specimens fail in the substrate zone rather than the repaired zone. However, the thermal exposure on the substrate during deposition causes slight growth of the κ<sub>Ⅱ</sub> phase in the heat-affected zone. The tensile strength of the samples repaired by DMD and UDMD is reduced by approximately 7 % compared to the cast substrate. This study proves the feasibility of in-situ underwater repair for large copper alloy components and can also provide new process references for controlling the evolution of microstructures through external environmental conditions during alloy manufacturing.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118659"},"PeriodicalIF":6.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analysis of grain structure, precipitation and hardness heterogeneities, supported by a thermal model, for an aluminium alloy 7075 deposited by solid-state multi-layer friction surfacing","authors":"Matthieu Jadot , Jishuai Li , Romain Gautier , Jichang Xie , Matthieu B. Lezaack , Thaneshan Sapanathan , Mohamed Rachik , Aude Simar","doi":"10.1016/j.jmatprotec.2024.118661","DOIUrl":"10.1016/j.jmatprotec.2024.118661","url":null,"abstract":"<div><div>Thermomechanical cycles during multi-layer friction surfacing (MLFS) cause microstructural and mechanical heterogeneities in the deposited high-strength Al alloy, 7075. The thermal profile and heat accumulation were investigated in this study using a multilayer numerical thermal model of the MLFS process; additionally, these variables were linked to experimentally observed microstructural heterogeneities. Compared with the feedstock, grain sizes decreased by 55–80 %. The mean grain size at the bottom and top areas of a given layer was finer than that in the middle of the layer because of the enhanced recrystallisation, which resulted from the friction and shear deformation experienced by the deposited material. The differences in the thermal cycle and plastic strain rate of the bottom and top areas along the layers resulted in a gradual increase in the grain size at the bottom of each layer and a reduction in the grain size at the top of each layer. The grain growth and continuous dynamic recrystallisation mechanisms are governed by the temperature and strain rate, those mechanisms determine the intra- and inter- layer grain sizes. The accumulated heat, owing to subsequent experimental deposition, resulted in excessive growth of the precipitates in the bottom layers. The strengthening of the solid-solution and Guinier-Preston zones significantly increased the microhardness of the top layer. Post-deposition T6 heat treatments confirmed the restoration of a uniform distribution of microhardness.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118661"},"PeriodicalIF":6.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weidong Liu , Ao Cheng , Haoyang Dong , Yonghua Zhao
{"title":"Electrochemical jet machining in deep-small holes with gas assistance: Generating complex features on internal surfaces","authors":"Weidong Liu , Ao Cheng , Haoyang Dong , Yonghua Zhao","doi":"10.1016/j.jmatprotec.2024.118662","DOIUrl":"10.1016/j.jmatprotec.2024.118662","url":null,"abstract":"<div><div>Deep-small holes with internal features have important applications in thermal engineering but pose significant difficulties for traditional machining methods. Electrochemical jet machining (EJM) is an effective surface micromachining technique with numerous merits. Applying EJM to create complicated features on the internal surface of deep-small holes is attractive. However, this concept remains challenging due to the narrow and enclosed processing space. In this work, a novel gas assistance tool is developed to achieve the EJM process in deep-small holes for the first time. The hydrodynamic conditions to realize well-shaped and unsubmerged jets in both open space and deep-small holes using the specifically designed tool are investigated. The appropriate electrolyte flow rates and sidewall orifice dimensions enable the desired jet to be ejected laterally from the tubular cathode sidewall orifice. While in the deep-small hole the assist gas creates a local gas cavity around the orifice to prevent the jet from submerging, forming the jet shape required for EJM and consequently achieving localized machining of the internal surface. Excessive assist gas pressure should be avoided as it causes the jet to incline and deform, resulting in reduced machining accuracy. Furthermore, the influence of the main parameters on machining performance is examined. The developed gas-assisted EJM method demonstrates similar machining characteristics to the conventional EJM process when appropriate gas assistance conditions can produce the well-shaped unsubmerged jet. As such, various features with smooth surfaces and good shape accuracy are successfully machined on the internal surface of deep-small holes.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118662"},"PeriodicalIF":6.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Understanding the process limits of folding-shearing","authors":"Rishabh Arora , Omer Music , Julian M. Allwood","doi":"10.1016/j.jmatprotec.2024.118660","DOIUrl":"10.1016/j.jmatprotec.2024.118660","url":null,"abstract":"<div><div>Globally, 44 % of sheet metal used in the production of passenger vehicles is scrapped. To reduce this scrap, folding-shearing has been proposed previously. In this process, a blank is first folded to collect excess material in a region of incompatibility. Folded sheet is then sheared in-plane to achieve the target geometry. In a preliminary study, folding-shearing was used to create a U-channel part in a compression testing machine and a process operating window was defined by considering failure limits of springback, thinning and thickening. For the first time, this study develops analytical models, validated with numerical models and physical trials to define process limits and generate an understanding of the underlying mechanics of the process limits. These analytical models can be used as a basis to develop a process operating window instantly and are shown to be within 25 % of the process limits found using numerical models and physical trials. Results show that springback, thinning and thickening limits are strongly influenced by the part radius, height, fold geometry, and material properties.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118660"},"PeriodicalIF":6.7,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A strain integrated gas infusion process (SIGI) for magnesium alloy castings","authors":"V. Tiwari , S.K. Panigrahi","doi":"10.1016/j.jmatprotec.2024.118658","DOIUrl":"10.1016/j.jmatprotec.2024.118658","url":null,"abstract":"<div><div>This study presents a Strain Integrated Gas Infusion Process (SIGI) to manufacture high-performance cast AZ91 magnesium alloys without the addition of secondary alloying elements/reinforcements or secondary processing. The current SIGI process involves a combination of agitation and localized rapid heat extraction via strain integration and high-energy gas infiltration. The SIGI casting process has been compared systematically with conventional techniques. The critical process parameters, including hole diameter, bubble diameter, and flow rate, have been optimized through numerical calculations, simulations, extensive experiments, and comprehensive analysis. The study also focused on investigating the effect of gas bubbles on the molten metal and established the mechanisms involved in improved solidification. Gas infusion combined with strain integration impacts the solidification process, ensuring uniform alloying element distribution and reducing segregation and microporosity. This manufacturing strategy eliminates casting defects such as segregation and microporosity, resulting in a non-dendritic homogeneous microstructure. The significant refinement in morphologies of both primary (α-Mg dendrites) and secondary (β-Mg<sub>17</sub>Al<sub>12</sub> phase) phases highlights the success of the current SIGI process. Compared to the conventional casting processes, a remarkable improvement in strength-ductility synergy is achieved in the current SIGI process. The scientific know-how and efficiency of the current SIGI process are established and discussed in detail, providing a promising solution to address the existing challenges encountered in magnesium alloy billet castings. The SIGI process improves the mechanical properties and corrosion resistance of billet-cast magnesium alloys. The SIGI process is suitable for the billet casting, offering significantly improved properties but faces limitations in complex mold casting applications. The billets casted by SIGI process can be used as a high-quality precursors for downstream processes to create industrial components.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118658"},"PeriodicalIF":6.7,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dongdong Yan , Yong Li , Wenbin Zhou , Zhen Qian , Liangbing Wang
{"title":"A one-step integrated forming and curing process for smart thin-walled fiber metal laminate structures with self-sensing functions","authors":"Dongdong Yan , Yong Li , Wenbin Zhou , Zhen Qian , Liangbing Wang","doi":"10.1016/j.jmatprotec.2024.118648","DOIUrl":"10.1016/j.jmatprotec.2024.118648","url":null,"abstract":"<div><div>This study proposes and analyzes a novel one-step integrated forming and curing (IFC) process for thin-walled fiber metal laminates (FMLs) structures embedded with fiber Bragg grating (FBG) sensors, and have achieved both high-performance properties and self-sensing functions in the formed structures. A prototype machine and testing setup have been developed to validate the process's feasibility by manufacturing high-performance FMLs flat and curvature parts with effective self-sensing capabilities for real-time manufacturing and in-service monitoring. Numerical models considering curing-induced deformation and heat transfer during manufacturing have also been developed to support the analysis and validation of the self-monitoring capabilities of the intelligent FMLs parts. The results reveal that with proper control of pressure (e.g., 0.6 MPa) and time during forming and curing, high tensile and impact performance of FMLs can be maintained with embedded FBG, with less than a 3 % loss. Additionally, the IFC process can effectively lead to an apparent reduction of springback deformation in the formed FMLs (more than 80 %). The validation of the self-sensing function during the manufacturing process has been achieved by comparing the strain monitoring results with finite element (FE) simulation results during curing, with a minimum discrepancy of 2.0 %. For the in-service self-sensing function, comparison between FE analysis and surface-fixed strain gauges during the compression instability test confirmed the efficacy of FBG sensors, with a minimum discrepancy of 4.3 %. The results show that the proposed novel IFC process enables the successful manufacture of smart thin-walled FMLs parts with high shape accuracy and mechanical properties in a single step and holds significant promise for manufacturing self-sensing smart structures in the aerospace and aviation industries.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118648"},"PeriodicalIF":6.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The microstructure evolution and embrittlement mechanism in the heat-affected zone of thick-plate titanium alloys fabricated by gas metal arc welding","authors":"Zhendan Zheng , Hao Wu , Shuaifeng Zhang , Zhiqian Liao , Shaojie Wu , Fangjie Cheng","doi":"10.1016/j.jmatprotec.2024.118657","DOIUrl":"10.1016/j.jmatprotec.2024.118657","url":null,"abstract":"<div><div>The efficient gas metal arc welding (GMAW) of thick-plate titanium alloys contributes to the application and promotion of large titanium alloy structural parts. However, the severe embrittlement behavior in the heat-affected zone (HAZ) seriously harms the service performance. In the current work, the microstructure evolution and tensile properties in HAZ are systematically analyzed by employing the thermal-mechanical simulation tests, and the embrittlement mechanism is innovatively elucidated for the first time by discussing the resistance and impetus to dislocation slip. The results showed that as it got closer to weld metal, the α phase underwent the transformation of “α<sub>p</sub> + α<sub>s</sub>→α<sub>p</sub>+α’→ghost α+α’→α’ + α<sub>GB</sub>”. Furthermore, the resistance to dislocation slip increased gradually due to the more severe lattice distortion, the higher density of high-angle grain boundaries (HAGBs), and the more intensive strain concentration, while the impetus decreased gradually due to the reduced Schmid factor (SF) of {0001}<11<span><math><mover><mrow><mn>2</mn></mrow><mo>̅</mo></mover></math></span>0> slip system. These led to the most severe embrittlement behavior occurring at the near-weld metal. The current work provides a valuable theoretical guide for welding quality optimization of large titanium alloy structural parts.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118657"},"PeriodicalIF":6.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhenkun Zhang, Daxiang Deng, Xin Gu, Long Zeng, Yingxue Yao
{"title":"Highly efficient fabrication of reentrant microchannels with micro serrated pin fins using a micro staggered multi-edge ball-end milling tool in a single process","authors":"Zhenkun Zhang, Daxiang Deng, Xin Gu, Long Zeng, Yingxue Yao","doi":"10.1016/j.jmatprotec.2024.118650","DOIUrl":"10.1016/j.jmatprotec.2024.118650","url":null,"abstract":"<div><div>Microchannels with micro pin fins and reentrant cavities can increase the heat dissipation area and enhance heat transfer, which are promising for high-performance microchannel heat sinks for heat dissipation of high-heat-flux devices. Nevertheless, their fabrication is time-consuming and cost-inefficient for conventional methods. To this aim, we in this study developed a novel micro staggered multi-edge ball end milling tool (SMBMT) to fabricate a unique type of reentrant microchannels with micro serrated pin fins (RMSPF) in a single process. The formation feasibility of the RMSPF was demonstrated, and they were of narrow exit slots with a width of 500 μm on the top, reentrant circular cavities with a diameter of 800 μm at the bottom, and micro serrated pin fins with a width of about 52 μm and a height of 35 μm on the wall surface of reentrant cavities. More microscale serrated pin fins with much smaller sizes than the micro cutting edges of the SMBMT were obtained due to the staggered arrangement and overlapping effect of the multiple micro cutting edges. A geometrical model of the SMBMT with discrete multiple cutting edges was developed by considering the structure of the RMSPF. The formation process mechanism of RMSPF and its chip formation process was investigated with both experiments and finite element (FE) simulations. Compared to conventional micro ball end milling tool (CBM) with continuous cutting edges, the SMBMT suppressed the burr formation inside reentrant microchannels and improved the surface quality, and reduced the cutting force by up to 53 %. The enhanced cutting performance of SMBMT can be attributed to that the multiple discrete cutting edges of SMBMT effectively decreased the contact area of tool-workpiece and the friction between cutting tool and chips. This study offered a highly efficient method to fabricate microchannels with surface microstructures in a single micromilling process, which provided valuable insights for the development of high-performance microchannel heat sinks in a wide range of application areas.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118650"},"PeriodicalIF":6.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Feijie Cui , Hang Zhang , Minghui Yang , Ben Deng , Xiaowei Tang , Fangyu Peng , Rong Yan , Zhiqian Pan
{"title":"Multiscale simulation and experimental study on ultrasonic vibration assisted machining of SiCp/Al composites considering acoustic softening","authors":"Feijie Cui , Hang Zhang , Minghui Yang , Ben Deng , Xiaowei Tang , Fangyu Peng , Rong Yan , Zhiqian Pan","doi":"10.1016/j.jmatprotec.2024.118649","DOIUrl":"10.1016/j.jmatprotec.2024.118649","url":null,"abstract":"<div><div>Ultrasonic vibration assisted machining (UVAM) is an attractive option to achieve high-quality and low-wear machining of the advanced composites. The scope of this paper is to evaluate the role of ultrasonic vibration on the microstructure and material removal mechanism for SiCp/Al composites. Firstly, an ultrasonic vibration assisted tension (UVAT) molecular dynamics (MD) simulation method for SiCp/Al composites is proposed. The simulation results verify the existence of acoustic softening effect for SiCp/Al composites under ultrasonic vibration loads. Furthermore, it is found that the acoustic softening originates from the dynamic evolution of the dislocations in the Al matrix. However, the acoustic softening is hardly mentioned in conventional finite element (FE) simulations depicting the microscopic removal mechanism of materials. In this paper, the constitutive correction method is adopted to realize it. The stress reduction of the Al matrix caused by acoustic softening is reverse-identified, and the maximum is 102 MPa. Finally, a novel FE model for UVAM of SiCp/Al composites considering acoustic softening is constructed, and the microscopic removal mechanism of SiCp/Al composites is revealed by the FE simulation and microscopic experimental results. On the one hand, the ultrasonic vibration enhances the stress relaxation of the Al matrix by reducing the dislocation density, and further enhances the deformation ability of SiCp/Al composites. On the other hand, the matrix tearing dominates the generation and propagation of shear band cracks in conventional machining (CM), while the dominant factor in UVAM is the finely broken SiC particles inside the shear band. This study enhances the understanding of the microscopic removal mechanism in UVAM for SiCp/Al composites.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"335 ","pages":"Article 118649"},"PeriodicalIF":6.7,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}