Polymer Composites最新文献

{"title":"Experimental investigation of the compressive behavior of epoxy nanocomposites reinforced with straight and helical carbon nanotubes","authors":"Soroush Saririan, Michael Borynski, Thomas Londono, Jose Arrango-Murillo, Kedar Kirane","doi":"10.1002/pc.29076","DOIUrl":"https://doi.org/10.1002/pc.29076","url":null,"abstract":"This paper is aimed at an experimental investigation of the effect of straight and helical carbon nanotubes on the compressive behavior of epoxy nanocomposites. The epoxy nanocomposites are fabricated with varying levels of SCNT and HCNT, each with two different fabrication techniques viz. high shear mixing and ultrasonication. In samples made using high shear mixing, the compressive strength is found to actually decrease, due to poor dispersion of the CNTs, resulting in voids and clumps, which can adversely affect the strength. Ultrasonic homogenization is found to better disperse the CNTs within the epoxy resin with nearly a 10-fold decrease in the heterogeneity size. Compression tests conducted on the ultrasonically homogenized CNT-epoxy nanocomposites indicate a modest increase in the compressive strength. The best increase of 5% is obtained with 1% SCNT. On the other hand, the HCNT samples show a higher post-peak residual stress suggesting an improved mode II/III fracture toughness. The high shear mixed samples exhibit a bulging deformation with no clear evidence of shear localization. On the other hand, the ultrasonic homogenization (UH) samples bulge and eventually show a clear localized shear band, likely due to a smaller heterogeneity size. Some samples with relatively poor dispersion exhibit an axial splitting failure and a comparatively low compressive strength. In addition, it is demonstrated that using acetone as a solvent during dispersion can affect the curing kinetics, which results in a nanocomposite with a rubbery consistency with low stiffness and strength, but high deformability.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"16 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253924","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":"Compressive and flexural properties and damage modes of aluminum foam/epoxy resin interpenetrating phase composites reinforced by silica powder","authors":"Mingming Su, Zhiming Zhou, Han Wang","doi":"10.1002/pc.29043","DOIUrl":"https://doi.org/10.1002/pc.29043","url":null,"abstract":"<jats:label/>Interpenetrating phase composites (IPCs) can combine the advantages of each component and have a good application prospect. IPCs were prepared by combining open‐cell aluminum foam (AF) and epoxy resin (EP) in three‐dimensional space in this study. Different contents of silica powder (SP, 80, 100, 120, and 140 wt%) were added to EP to improve the compressive and three‐point bending properties of IPCs. In the bending test, acoustic emission (AE) was applied to track the bending deformation of the samples, and <jats:italic>k</jats:italic>‐means clustering algorithm was applied to identify the damage modes. The compressive and bending properties of IPCs increased first and then decreased with the increase of SP content, and reached the maximum when the SP content was 100 wt%, with a compressive yield strength of 74.6 MPa and a bending peak load of 1.96 kN. The performance degradation was mainly attributed to the AF/EP debonding due to SP distribution at the interface. The X‐type shear band and EP/AF debonding appeared in compression failures of AF and IPCs, respectively. The AE clustering results showed that under bending load, plastic deformation of matrix (60–200 kHz) and fracture failure (230–340 kHz) modes appeared in AF, while EP/AF debonding (60–120 kHz), EP failure (120–230 kHz) and plastic deformation of foam matrix (230–250 kHz) modes appeared in IPCs.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Silica powder was added to improve compressive and bending properties of IPCs.</jats:list-item> <jats:list-item>Acoustic emission was used to monitor bending of foam and IPCs firstly.</jats:list-item> <jats:list-item><jats:italic>k</jats:italic>‐means clustering was used to identify and classify bending damage patterns.</jats:list-item> </jats:list>","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"12 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253983","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":"A stacking sequence optimization strategy for process-induced deformation of multi-layer thick asymmetric laminates","authors":"Hongli Jia, Yingdan Zhu, Chun Yan, Gang Chen, Dong Liu","doi":"10.1002/pc.29048","DOIUrl":"https://doi.org/10.1002/pc.29048","url":null,"abstract":"The occurrence of process-induced deformations of composites laminates is challenging for assembly accuracy and may lead to a service life reduction of parts. However, it can be obviously mitigated through different optimization strategies on the basis of the accurate curing process simulation. In this study, a stacking sequence optimization strategy is proposed and applied to multi-layer thick asymmetric laminates. The shapes of deformed laminate plates are experimentally investigated in virtue of the three-dimensional coordinate measuring machine. The thermo-chemical–mechanical behaviors of plates are first verified through the comparisons of model predicted and experimental process-induced deformations. Then the nonlinear control formula achieved through the regression model is proposed for the direct relationship between stacking sequences and process-induced deformations. Finally, the required solutions are generated by solving the control formula. With the comparisons between the average deformations before and after optimizations, it is found that the magnitudes of deformations are significantly reduced, especially when the unoptimizated deformations are large.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"13 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253974","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":"Effect of geometric configurations and curvature angle of corrugated sandwich structures on impact behavior","authors":"Ilyas Bozkurt","doi":"10.1002/pc.29064","DOIUrl":"https://doi.org/10.1002/pc.29064","url":null,"abstract":"The aim of this study is to numerically investigate the low-velocity impact behavior of carbon fiber reinforced orthogonal woven fabric composite sandwich structures with five different geometric configurations and four different curve angles. Low velocity impact simulations were performed in <i>LS DYNA</i> finite element program to investigate the effects of core configuration and curve angle on peak contact force, energy absorption efficiency and damage mode. A progressive damage analysis based on the combination of the Hashin damage criterion and the <i>Cohesive Zone Model (CZM)</i> with <i>bilinear traction-separation law</i> was performed using the <i>MAT-54 (ENHANCED_COMPOSITE_DAMAGE)</i> material model. Among the five different cores, Trapezoidal core has the highest peak force average of 2.9 kN while Triangular core sandwich structure has the lowest with 1.23 kN. Absorbed energy efficiency average was highest for rectangular core with 0.95 and lowest for sinusoidal core with 0.69. The specific absorbed energy value was highest for Triangular core with 0.312 J/g and lowest for Sinusoidal core with 0.178 J/g. The damage area on the structure increased with increasing curve angle. It was determined that the core structure and curve angle is an effective parameter on peak force and energy absorption efficiency.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"9 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253975","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":"Preparation and characterization of a multifunctional film with excellent UV shielding, antibacterial and antioxidant capabilities containing cinnamaldehyde and titanium dioxide (TiO2)","authors":"Xiangnan Chen, Siwen Li, Jihuan Liang, Ningdong Hu","doi":"10.1002/pc.29057","DOIUrl":"https://doi.org/10.1002/pc.29057","url":null,"abstract":"Soy protein isolated (SPI) have a wide application in the food packaging, but their water resistance, mechanical properties and antibacterial properties are not ideal for directly use. In our study, we developed a series of SPI composite films loaded with cinnamaldehyde and titanium dioxide (TiO₂). X-ray diffraction (XRD), UV scanning spectra (UV) and spectro colorimeter were applied to indicate the structure of films. The incorporation of TiO₂ (0.5%) caused a subsequent effect on the tensile property, UV blocking properties and water vapor properties (WVP). On the other hand, SPI film composed with a constant amount of TiO₂ and different concentration of cinnamaldehyde showed an excellent synergistic effect to improve the tensile property, moisture content, UV blocking properties, water vapor properties and morphological characteristics. Furthermore, the composite films exhibited superior antibacterial activity when tested against both <i>S. aureus</i> and <i>E. coli</i>. The microstructure of the composite film become heterogeneous and rough after addition of TiO₂ and cinnamaldehyde compare to control film. The findings of the present study may facilitate a re-evaluation of the potential of using multiple compounds to prepare active edible films.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"66 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253980","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":"Experimental investigation on low-velocity impact performance of carbon fiber reinforced polyether ether ketone thermoplastic composite materials in room and elevated temperature","authors":"Chen Yang, Chunjian Mao, Chao Zhang","doi":"10.1002/pc.29052","DOIUrl":"https://doi.org/10.1002/pc.29052","url":null,"abstract":"Carbon fibers woven-ply reinforced polyether ether ketone (C/PEEK) thermoplastic composites are widely used in aerospace and high-tech industries because of their exceptional resistance to low-velocity impact. In this paper, experimental investigation is carried out to determine the low-velocity impact performance of C/PEEK laminates at room temperature (RT) and high temperature (90°C and 150°C) environments. Both macroscopic and microscopic analyses are applied to examine the influence of temperature on the mechanical response and damage mode of the material. The attention of this investigation is on impact parameters such as maximum contact force, energy absorption rate, indentation depth, and damage mode. The findings show significant changes in material stiffness, rate of energy absorption, and indentation depth with rising temperature. Temperature variations have a notable effect on the PEEK matrix plasticity, C/PEEK composite interlaminar properties, crack initiation and propagation, and damage mode at the overlaps of warp and weft fibers, resulting in a transition from brittle to ductile failure.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"64 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253977","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":"Advances in nanomaterials as exceptional fillers to reinforce carbon fiber-reinforced polymers composites and their emerging applications","authors":"Yuxin Luo, Zhicheng Shi, Sijie Qiao, Aixin Tong, Xiaohong Liao, Tongrui Zhang, Jie Bai, Chao Xu, Xiaoman Xiong, Fengxiang Chen, Weilin Xu","doi":"10.1002/pc.29027","DOIUrl":"https://doi.org/10.1002/pc.29027","url":null,"abstract":"Carbon fiber reinforced polymer (CFRP) composites exhibit excellent characteristics such as light weight, high specific strength, specific stiffness, and chemical stability, making them customizable to meet the specific demands of various sectors such as the automotive, aerospace, defense, biomedical, and energy industries. However, the inert surface of carbon fibers (CFs) results in a poor interface compatibility with polymer matrices, leading to numerous interfacial defects and pores in prepared CFRP composites. These drawbacks significantly limit the application of CFRP composites in high-end fields. The higher surface area and smaller size of nanomaterials provide multiple advantages for high-performance CFRP composites that enhance the mechanical properties, impact resistance and interface adhesion between the fiber and the matrix. Hence, this review firstly summarizes the interfacial behavior and interface enhancement mechanisms for CFRP composites. Subsequently, we comprehensively review the recent advances in various nanomaterials-modified CFRP composites, including carbon-based nanoparticles, silicon-based nanomaterials and metal nanomaterials, et al. Besides, we also present the applications of CFRP in emerging fields, such as military, aerospace, automotive, sports equipment, and medical, etc. Finally, we also prospected the challenges and future development trends of CFRP composites, aiming to provide new ideas and insights for future research on nanomaterial modifications and promote the development of high-performance CFRP composites.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"16 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253976","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":"Enhancing the interlaminar property of carbon fiber/poly(aryl ether ketone) composites with water-soluble polyimide oligomer sizing agent","authors":"Dongting Gao, Gang Liu, Le Dong, Jindong Zhang, Jianan Yao, Chunhai Chen","doi":"10.1002/pc.29084","DOIUrl":"https://doi.org/10.1002/pc.29084","url":null,"abstract":"Novel water-soluble polymer-based sizing agents for carbon fiber/poly(aryl ether ketone) composites (CF/PAEK) have gained attention. However, a challenge remains: the sized CF bundles lack flexibility, and the effect of this on the properties of the composite has not been discussed. Herein, a water-soluble polyimide oligomer (OL) sizing agent was developed, and the sizing effect was comprehensively evaluated. The conventional molecular weight polyimide (HP) sizing agent was also assessed for comparison. Although the interfacial shear strength of the sized CF monofilaments is enhanced due to improved surface roughness and wettability, the effect of the OL sizing agent on the composite's interlaminar shear strength (ILSS) and tow's flexibility differed from that of the HP sizing agent. Compared with HP-CF, the yarn spreading rate of OL-CF tow is increased by about eight times, and the ILSS of OL-CF/PAEK composites with 2 and 5 MPa molding pressure is increased by 69% and 222%, respectively. The HP sizing agent weakens the tow's flexibility and yarn spreading ability, which is not conducive to the resin penetration in the tow, resulting in lower ILSS. In contrast, the OL sizing agent considers the tow's flexibility and composite's interlaminar property, showing great application potential.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"44 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253978","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":"Low-velocity impact resistance of the Z-pin reinforced carbon fiber composite laminates","authors":"Wenyun Wu, Zhangxin Guo, Haolin Shi, Weijing Niu, Gin Boay Chai, Yongcun Li","doi":"10.1002/pc.29066","DOIUrl":"https://doi.org/10.1002/pc.29066","url":null,"abstract":"A voronoi user material subroutine (VUMAT) was developed using the three-dimensional Hashin damage criterion and exponential nonlinear damage evolution method. An interlayer damage model based on the quadratic nominal stress (QUADS) criterion and B-K fracture criterion was introduced, and a finite element model of Z-pin reinforced composite laminates under low-velocity impact was established. The low-velocity impact behavior of Z-pin reinforced composite laminates with different impact velocities (0.6 m/s, 0.4 m/s, and 0.3 m/s), different layup forms ([0°/90°]₄ and [0°/45°/90°/−45°]₂), and different Z-pin spacing (4 mm, 8 mm, and 16 mm) was studied using ABAQUS. The results indicate that different layup forms have little effect on the low-velocity impact behavior of Z-pin reinforced composite laminates. The Z-pin spacing has a significant influence on the low-velocity impact behavior of Z-pin reinforced composite laminates. When the impact velocity is 0.4 m/s, the specific energy absorption of composite laminates with Z-pin spacing of 16 mm is 85.93% and 87.7% lower than that of composite laminates with Z-pin spacing of 4 mm and 8 mm. As the Z-pin spacing decreases (Z-pin density increases), the impact resistance of Z-pin reinforced composite laminates first increases and then decreases.","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"30 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253979","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":"Energy absorption properties of origami-based re-entrant honeycomb sandwich structures with CFRP subjected to low-velocity impact","authors":"Zhen Cui, Yuechen Duan, Jiaqi Qi, Feng Zhang, Bowen Li, Mingyu Liu, Peng Jin","doi":"10.1002/pc.29078","DOIUrl":"https://doi.org/10.1002/pc.29078","url":null,"abstract":"This paper investigates a honeycomb sandwich structure that draws inspiration from the craft of origami. A specific folding pattern was applied to the honeycomb to create the origami-based re-entrant honeycomb (ORH), aimed at improving the energy absorption properties of the sandwich structure. The study on the energy absorption properties of structures under low-velocity impact (LVI) utilized both experimental and numerical approaches. The energy absorption properties of the sandwich structure were examined by conducting LVI tests with different impact energy and then compared to the mechanical properties of the traditional re-entrant honeycomb sandwich structures (TRHSS). Additionally, a refined finite element model has been established and its accuracy verified. Numerical studies were conducted to explore the effects of structural parameters on the energy absorption properties of ORH sandwich structure (ORHSS). The results show that the ORHSS exhibited a significant reduction in peak force when subjected to LVI, in contrast to the TRHSS. Furthermore, the ORHSS exhibit significant efficiency in energy absorption. Enhancing the wall thickness &lt;span data-altimg=\"/cms/asset/72b94ed9-b96f-4ccc-a607-de8852e83e3c/pc29078-math-0001.png\"&gt;&lt;/span&gt;&lt;mjx-container ctxtmenu_counter=\"4\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"&gt;&lt;mjx-math aria-hidden=\"true\" location=\"graphic/pc29078-math-0001.png\"&gt;&lt;mjx-semantics&gt;&lt;mjx-mrow&gt;&lt;mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"t\" data-semantic-type=\"identifier\"&gt;&lt;mjx-c&gt;&lt;/mjx-c&gt;&lt;/mjx-mi&gt;&lt;/mjx-mrow&gt;&lt;/mjx-semantics&gt;&lt;/mjx-math&gt;&lt;mjx-assistive-mml display=\"inline\" unselectable=\"on\"&gt;&lt;math altimg=\"urn:x-wiley:02728397:media:pc29078:pc29078-math-0001\" display=\"inline\" location=\"graphic/pc29078-math-0001.png\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;semantics&gt;&lt;mrow&gt;&lt;mi data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic-role=\"latinletter\" data-semantic-speech=\"t\" data-semantic-type=\"identifier\"&gt;t&lt;/mi&gt;&lt;/mrow&gt;$$ t $$&lt;/annotation&gt;&lt;/semantics&gt;&lt;/math&gt;&lt;/mjx-assistive-mml&gt;&lt;/mjx-container&gt; or folding angle &lt;span data-altimg=\"/cms/asset/b167129f-2d5c-4077-9419-bebf8f11e2fb/pc29078-math-0002.png\"&gt;&lt;/span&gt;&lt;mjx-container ctxtmenu_counter=\"5\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"&gt;&lt;mjx-math aria-hidden=\"true\" location=\"graphic/pc29078-math-0002.png\"&gt;&lt;mjx-semantics&gt;&lt;mjx-mrow data-semantic-children=\"0,2\" data-semantic-content=\"1\" data-semantic- data-semantic-role=\"division\" data-semantic-speech=\"upper V divided by upper H\" data-semantic-type=\"infixop\"&gt;&lt;mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"latinlett","PeriodicalId":20375,"journal":{"name":"Polymer Composites","volume":"3 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142254032","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}