Additive manufacturing最新文献

{"title":"Single-photon-assisted two-photon polymerization","authors":"Buse Unlu ,&nbsp;Maria Isabel Álvarez-Castaño ,&nbsp;Antoine Boniface ,&nbsp;Ye Pu ,&nbsp;Christophe Moser","doi":"10.1016/j.addma.2024.104455","DOIUrl":"10.1016/j.addma.2024.104455","url":null,"abstract":"<div><div>Light-based additive manufacturing (AM) has revolutionized the fabrication of complex three-dimensional objects offering a cost-effective and high-speed alternative to traditional machining. Single-photon polymerization is a key process in this advancement, providing rapid printing time, albeit with limited resolution in the range of tens of micrometers. Two-photon polymerization provides sub-micrometer resolution but is accompanied by a tradeoff of prolonged printing times. We propose combining single- and two-photon absorption to benefit from the dual capabilities, allowing for faster printing time while maintaining high resolution. In this study, we employ a continuous-wave blue light source to pre-sensitize a photocurable resin by single-photon absorption followed by a tightly focused femtosecond laser beam to provide the required energy reaching the polymerization threshold for solidifying the resin through two-photon absorption. We first investigate the impact of pre-sensitization by blue light illumination followed by irradiation with a focused femtosecond laser beam and find that the voxel growth dynamics are markedly altered. Specifically, pre-sensitization by blue light lowers the polymerization threshold power of the femtosecond laser beam and increases the speed of voxel growth. We then exploit this effect by building a custom two-photon 3D printer in which the blue light pre-sensitization is created in a light-sheet configuration. We report successfully printed 3D objects for which the average femtosecond laser power was reduced by 28.6 % and the exposure time was reduced by a factor of two compared with polymerization performed only with the femtosecond laser beam. Additionally, a 63 % improvement in axial voxel size is attained through blue light-sheet pre-sensitization. Our theoretical analysis based on a diffusion-free model suggests that the mechanism of the pre-sensitization is oxygen depletion followed by a single-photon background latent polymerization.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104455"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effective post-cleaning strategy for vat photopolymerization 3D printed complex-structured polymer-derived ceramics","authors":"Chongyu Long ,&nbsp;Long Jiang ,&nbsp;Shufeng Xiong ,&nbsp;Zhiyuan Liu ,&nbsp;Changyong Liu ,&nbsp;Zhangwei Chen","doi":"10.1016/j.addma.2024.104456","DOIUrl":"10.1016/j.addma.2024.104456","url":null,"abstract":"<div><div>Achieving ideal surface quality and high structural integrity of complex-structured polymer-derived ceramics manufactured by vat photopolymerization 3D printing not only depends on the high temperature pyrolysis processing, but also greatly relies on the complete removal of uncured resin on the surface and internal holes of the green bodies before pyrolysis. In this work, based on the characteristics of precursor resins and printed bodies, a novel cleaning strategy with excellent cleaning efficiency and the corresponding cleaning agent with good flowability, appropriate solubility, and strong volatility are proposed. The cleaning agent consists of two monomers, butyl acrylate (BA), and 1,6-hexanediol diacrylate (HDDA), which are components of the precursor resin, thereby avoiding chemical reactions between the cleaning agent and the printed bodies. Meanwhile, by adjusting their proportions, suitable solubility and volatility are achieved. Appropriate solubility ensures that under diluted conditions, it does not damage the cured resin, while strong volatility removes the diluted uncured resin in a short time. Additionally, good flowability enables thorough penetration into the internal holes to mix with and contact the uncured resin. This cleaning process achieves efficient and high-quality cleaning of ceramic precursor 3D printed bodies. The superiority of this strategy is confirmed by observing and characterizing the pyrolyzed samples. It achieves high surface quality, structural fidelity, and no crack defects, with 100 % opening of 150μm diameter holes, high through-hole rates, low surface roughness, and peak-to-valley height. In contrast, traditional cleaning processes have lower through-hole rates, higher roughness, and suffer from structural distortion and cracks. Thus, the proposed post-cleaning strategy provides a guidance on the design and selection of cleaning agents and methods for effective cleaning of these ceramic samples derived from similar ceramic precursors.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104456"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive support-free slicing method library for variable posture additive manufacturing","authors":"Zhengren Tong ,&nbsp;Xiaoling Yu ,&nbsp;Chen Yang ,&nbsp;Hongyao Shen","doi":"10.1016/j.addma.2024.104508","DOIUrl":"10.1016/j.addma.2024.104508","url":null,"abstract":"<div><div>Support-free slicing technology plays a critical role in additive manufacturing by reducing costs and simplifying post-processing. However, due to the complexity of geometric features, existing support-free slicing strategies often lack the necessary universality in industry. This paper proposes a method library comprising six basic support-free slicing methods to enhance the applicability and computational efficiency. The general methods in the library include facet-based methods and voxel-based methods, the former facilitates rapid slicing, while the latter enables the re-decomposition of complex structural parts. For parts that cannot be covered by general methods, customized methods are developed. These include constructing a support bridge for multi-direction slicing of overhanging regions in an arch model and extracting the optimal central axis for internal channels to achieve precise channel decomposition. Additionally, the methods in the library can be flexibly combined. By recognizing surface features and incorporating manual intervention, models can be decomposed into multiple sub-models, with the most computationally efficient method is matched to each sub-model. The layers and tool-paths of each sub-model are generated by the optimal method. Four typical models are deposited without any support in a five-axis printer to verify the feasibility of the proposed methods.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104508"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The development and characterisation of 3D-printed multi-material thermistor","authors":"Umur I. Cicek ,&nbsp;Darren J. Southee ,&nbsp;Andrew A. Johnson","doi":"10.1016/j.addma.2024.104510","DOIUrl":"10.1016/j.addma.2024.104510","url":null,"abstract":"<div><div>This paper introduces a multi-material, low-cost, and highly sensitive thermistor concept developed for body temperature monitoring. The designed thermistor utilises poly(3,4-ethylenedioxythophene):poly(4-styrenesulfonate) (PEDOT:PSS) for the temperature sensing layer, silver (Ag) for the contact electrodes, and polycarbonate (PC) as the substrate. In contrast to traditional printed electronics substrates used in thermistor development, the utilisation of Material Extrusion via Fused Deposition Modelling (FDM) for the manufacture of PC substrates is the distinct feature of the work. For the manufacture of multi-material thermistors, two different Additive Manufacturing (AM) methods, FDM for substrates and micro dispensing for PEDOT:PSS sensing layer and Ag electrodes, were employed. Two thermistors with varying sensing areas, namely D1 and D2, were designed and fabricated. The thermistors demonstrated a high degree of linearity and repeatability within the temperature range of 25–45°C with a viable hysteresis maximum around 3 %. The measurement sensitivity of thermistors was assessed based on Temperature Coefficient of Resistance (TCR) values, which were –0.68 ±0.057 % and –0.49 ±0.078 % per °C for the D1 design and –0.53 ±0.078 % and –0.40 ±0.069 % per °C for the D2 design, during heating and cooling, respectively. Comparable average response and recovery times to those reported in the literature were also acquired, which were 31.47 ±1.02 and 54.42 ±0.70 seconds for the D1 design and 27.38 ±0.96 and 48.45 ±1.69 seconds for the D2 design, during heating and cooling, respectively. It was evident that the sensing area had an impact on thermistor TCR as well as response and recovery times, where higher TCR and faster response and recovery times were recorded with the small sensing area. It was also observed that humidity had a significant impact on thermistor reliability, exhibiting a normalised resistance change of ∼12 % and ∼9 % of the initial measurement at 50 % and 75 % RH, respectively. When compared to PEDOT:PSS-based thermistors reported in the literature, the obtained results in this research have demonstrated that our multi-material thermistor concept is a promising candidate for the low-cost and highly sensitive multi-material thermistor that can be manufactured in a fully additive manner using AM technologies.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104510"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tomographic projection optimization for volumetric additive manufacturing with general band constraint Lp-norm minimization","authors":"Chi Chung Li ,&nbsp;Joseph Toombs ,&nbsp;Hayden K. Taylor ,&nbsp;Thomas J. Wallin","doi":"10.1016/j.addma.2024.104447","DOIUrl":"10.1016/j.addma.2024.104447","url":null,"abstract":"<div><div>Tomographic volumetric additive manufacturing is a rapidly growing fabrication technology that enables rapid production of 3D objects through a single build step. In this process, the design of projections directly impacts geometric resolution, material properties, and manufacturing yield of the final printed part. Herein, we identify the hidden equivalent operations of three major existing projection optimization schemes and reformulate them into a general loss function where the optimization behavior can be systematically studied, and unique capabilities of the individual schemes can coalesce. The loss function formulation proposed in this study unified the optimization for binary and greyscale targets and generalized problem relaxation strategies with local tolerancing and weighting. Additionally, this formulation offers control on error sparsity and consistent dose response mapping throughout initialization, optimization, and evaluation. A parameter-sweep analysis in this study guides users in tuning optimization parameters for application-specific goals.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104447"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the layer-wise dynamics of defect evolution in laser powder bed fusion: Insights for in-situ monitoring and control","authors":"Xiangyuan Chen,&nbsp;Wenhe Liao,&nbsp;Jiashun Yue,&nbsp;Tingting Liu,&nbsp;Kai Zhang,&nbsp;Jiansen Li,&nbsp;Tao Yang,&nbsp;Haolin Liu,&nbsp;Huiliang Wei","doi":"10.1016/j.addma.2024.104414","DOIUrl":"10.1016/j.addma.2024.104414","url":null,"abstract":"<div><div>Lack of fusion (LOF) defects can significantly affect the mechanical properties of components manufactured by laser powder bed fusion (LPBF). The layer-wise evolution of LOF defects is complex and not yet thoroughly understood. This work explores the spatiotemporal variations of LOF defects under various conditions using in-situ monitoring, ex-situ surface topography and μ-CT porosity characterization, and high-fidelity multi-physics numerical simulation. The results show that LOF defects could exhibit typical self-healing characteristics for over five printing layers. The specific self-healing behaviors depend on the initial sizes of the defects and the LPBF process conditions. The evolution of LOF defects can be detected by in-situ monitoring using light intensity. However, the in-situ monitoring may miss detecting LOF defects buried below the healed layers, which were alternatively observed via μ-CT. For the defective area with a depth of 150 μm, the relative density increased from 61.7 % to 95.7 % for the first to the fifth printing layer. The optimization of process parameters demonstrated that the application of a 45° scanning angle could significantly enhance surface flatness and repair internal pores to a minimum of 36.0 μm. The findings highlight the ability of in-situ monitoring in detecting LOF defects and the potential of the controlled printing process to accelerate defect repair. These outcomes offer valuable insights for the industrial applications of in-situ monitoring and control during LPBF.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104414"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface quality evaluation through new optical imaging system-based objective speckle for additive manufactured titanium samples","authors":"Samar Reda Al-Sayed,&nbsp;Doaa Youssef","doi":"10.1016/j.addma.2024.104475","DOIUrl":"10.1016/j.addma.2024.104475","url":null,"abstract":"<div><div>Laser cladding is an effective additive manufacturing technology used for materials’ surface modification to enhance their surface and mechanical properties. Surface roughness is a crucial feature that affects the materials’ quality and lifespan. Additionally, it is a real indicator of hardness and wear resistance. Although the existing methods may precisely measure surface roughness, they require delicate adjustment, can damage surfaces, and have limited working distances. This study presents a novel optical imaging system to quantitatively estimate the quality modifications of additive manufacturing samples by measuring their surface roughness based on objective speckle and advanced multivariate analysis methods. The raw speckle patterns are generated from deposited layers on Ti6Al4V titanium alloys obtained at different laser processing parameters. The proposed analysis approach produces collections of local statistical matrices from which histogram features are extracted. Canonical correlation analysis (CCA) is then proposed to distinguish the most significant features. The correlation between the features (with and without applying CCA) and surface roughness is established by using two machine learning regression algorithms, nonlinear support vector regression (SVR), random forest regression (RF), and k-nearest neighbor regression (kNN). The results confirmed that combining RF and CCA provided a feasible regression model to estimate the surface roughness, with 0.998 for R² in training samples and maximum values of 0.258, 0.484, and 4.593 %, respectively, for MAE, RMSE, and MAPE in test samples. This demonstrates that the proposed objective speckle imaging system is effective in estimating the quality modification of additive manufacturing samples by measuring their surface roughness.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104475"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deciphering the microstructural development and excellent ductility in electron beam wire-fed additive manufacturing of Ti-6Al-3Nb-2Zr-1Mo alloys based on high deposition rate","authors":"Guoqiang Zhu ,&nbsp;Liang Wang ,&nbsp;Baoxian Su ,&nbsp;Binbin Wang ,&nbsp;Ran Cui ,&nbsp;Hui Yan ,&nbsp;Botao Jiang ,&nbsp;Jiachen Zhou ,&nbsp;Ruirun Chen ,&nbsp;Liangshun Luo ,&nbsp;Yanqing Su ,&nbsp;Jingjie Guo","doi":"10.1016/j.addma.2024.104485","DOIUrl":"10.1016/j.addma.2024.104485","url":null,"abstract":"<div><div>Electron beam wire-fed (EBWF) additive manufacturing has higher energy density and greater deposition efficiency than powder bed and is suitable for the large-sized parts, with giving rise to larger melt pool size and thermal accumulation, consequently easily forming greater microstructural heterogeneity. This work investigates marine Ti-6Al-3Nb-2Zr-1Mo (Ti6321) alloys based on the intrinsic deposition characteristics of EBWF to better understand the nature of heterogeneous microstructure in high deposit rate processes. Meanwhile, these microstructures are replicated by the cyclic heat treatment to <em>in situ</em> observe the microstructural evolution. The results indicate that the heterogeneous nucleation and α/β boundaries migration primarily govern the formation of fine colony band and coarsening basket-weave microstructure, respectively. And the repeated α↔β transformation creates an opportunity for α globularization during deposition, involving in activity of high-density dislocations. Besides, the varying capacity of resistance to deformation at the onset of plastic deformation, resistance to crack initiation and propagation at the non-uniform deformation stage contribute to the different tensile responses when loading along Z and X direction. As part of this work, the stress-induced martensite transformation behavior in β phase is discovered for the first time even though the minor β volume fractions in as-deposited Ti6321 alloys, which plays an innegligible contribution to enhancing ductility. Overall, the work provides valuable insights into the microstructural evolution, globalization mechanisms and excellent ductility in the as-deposited Ti alloys fabricated by high deposit rate process.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104485"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated 3D printing of reconfigurable soft machines with magnetically actuated crease-assisted pixelated structures","authors":"Youchao Zhang ,&nbsp;Xiaoyang Zhu ,&nbsp;Huangyu Chen ,&nbsp;Ruichen Wang ,&nbsp;Siqi Qiu ,&nbsp;Houchao Zhang ,&nbsp;Hongke Li ,&nbsp;Zhenghao Li ,&nbsp;Rui Wang ,&nbsp;Fan Zhang ,&nbsp;Guangming Zhang ,&nbsp;Yuan-Fang Zhang ,&nbsp;Dong Wang ,&nbsp;Hongbo Lan","doi":"10.1016/j.addma.2024.104513","DOIUrl":"10.1016/j.addma.2024.104513","url":null,"abstract":"<div><div>Reconfigurable magnetic soft machines have a wide range of applications in soft robotics, aerospace, medical devices and flexible electronics. However, the high-precision reconfiguration of magnetically actuated soft machines is hindered by the absence of rational structural design and integrated manufacturing techniques. Here, we report an innovative design and manufacturing approach to realize magnetically actuated high-precision reconfigurability. We present a crease-assisted pixelated design using a mixture of magnetic particles and phase-change medium as the pixel points, with an elastomer as the crease to connect the pixel points, simulating origami. The design of elastomer creases improves pixel stiffness without loss of reconfigurable accuracy, thereby significantly improves the magnetic particle concentration in the pixel. An effective multi-material 3D printing technique is used to achieve the integrated printing of the designed structure. The resulting magnetically actuated soft machines exhibit remarkable capabilities, achieving small curvature bending and precise reconfiguration with weaker actuating magnetic fields (100mT). The superior performance of this design has been confirmed through demonstrations of crawling and rolling machines, magnetically controlled switches, and logic circuits. The work enhances the reconfiguration accuracy of magnetically actuated soft machines, increasing their potential for soft robotics and flexible electronics applications.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104513"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards personalized microfluidics: 3D printing of high-performance micropumps by control and optimization of fabrication-induced surface roughness","authors":"Mustafa M. Fadlelmula ,&nbsp;Babak Mazinani ,&nbsp;Vivek Subramanian","doi":"10.1016/j.addma.2024.104468","DOIUrl":"10.1016/j.addma.2024.104468","url":null,"abstract":"<div><div>Additive fabrication technologies are very attractive for use in the realization of customized medical diagnostic and point-of-care devices in the rapidly growing field of personalized healthcare. However, non-idealities in additive manufacturing processes, such as the enhanced roughness that is inherent to many such processes, limit the use of these fabrication technologies in real products. In this work, the effect of additive fabrication-induced surface roughness on fluid flow within material extrusion (MEX) 3D-printed microfluidic devices is modeled and experimentally validated. An optimization process to eliminate such effects in functional 3D-printed devices is developed. By the resulting careful model-driven optimization, high-performance printed glass and Acrylonitrile butadiene styrene (ABS) valveless micropumps are demonstrated in this work for the first time. Water flow rates of 210 µl min⁻¹ and 140 µl min⁻¹ for the ABS and the glass micropumps respectively, and a maximum working backpressure of 978 Pa at an actuation signal of 68 Hz and 120 V_pp are achieved, attesting to the viability of additive fabrication to realize functional microfluidic devices.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104468"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}