Additive manufacturing最新文献

{"title":"Spatter transport in a laser powder-bed fusion build chamber","authors":"Oluwatobi H. Aremu ,&nbsp;Faisal S. Alneif ,&nbsp;Mohammad Salah ,&nbsp;Hasan Abualrahi ,&nbsp;Abdulaziz M. Alotaibi ,&nbsp;Awad B.S. Alquaity ,&nbsp;Usman Ali","doi":"10.1016/j.addma.2024.104439","DOIUrl":"10.1016/j.addma.2024.104439","url":null,"abstract":"<div><div>The adverse effects of spatter particles are well known in laser powder-bed fusion (LPBF) additive manufacturing. To prevent the deposition of spatter particles, an inert gas flow is commonly used to transport these spatters away from the build plate. However, the inert gas flow does not remove all spatters due to varying spatter sizes and ejection angles. Therefore, it is essential to understand and predict spatter trajectories to achieve superior LPBF parts. The present study focuses on numerical modelling of spatter trajectories in Renishaw AM250 using an Eulerian-Lagrangian discrete phase model. The argon velocity profile and spatter trajectories with and against the flow are computed for various materials, sizes and ejection angles. The simulation results are validated with experimental results and show a presence of uneven flow due to inlet geometry along with varying flow profiles across the build height due to inlet location. Spatter analysis shows three methods which result in spatter deposition. Spatter particles either fall directly on the build plate, are transported by the airflow or are re-directed in the recirculation zone. The findings presented in this work indicate the importance of build chamber design along with material-based parameter optimization that results in maximum spatter removal.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104439"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358179","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":"Fatigue life prediction of rough Hastelloy X specimens fabricated using laser powder bed fusion","authors":"Ritam Pal ,&nbsp;Brandon Kemerling ,&nbsp;Daniel Ryan ,&nbsp;Sudhakar Bollapragada ,&nbsp;Amrita Basak","doi":"10.1016/j.addma.2024.104450","DOIUrl":"10.1016/j.addma.2024.104450","url":null,"abstract":"<div><div>Additive manufacturing, especially laser powder bed fusion (L-PBF), is extensively used for fabricating metal parts with intricate geometries. However, parts produced via L-PBF suffer from varied surface roughness, which affects the fatigue properties. Accurate prediction of fatigue properties as a function of surface roughness is a critical requirement for qualifying L-PBF parts. In this work, an analytical methodology was put forth to predict the fatigue life of L-PBF components having heterogeneous surface roughness. Thirty-six Hastelloy X specimens were printed using L-PBF followed by industry-standard heat treatment procedures. Half of these specimens had as-printed gauge sections and the other half were printed as cylinders from which fatigue specimens were extracted via machining. Specimens were printed in a vertical orientation and an orientation of 30° from the vertical axis. The surface roughness of the specimens was measured using computed tomography and parameters such as the maximum valley depth were used to build an extreme value distribution. Fatigue testing was conducted at an isothermal condition of 500 °F. It was observed that the rough specimens failed much earlier than the machined specimens due to the deep valleys present on the surfaces of the former ones. The valleys behaved as notches leading to high strain localization. Based on this observation, an analytical functional relationship was formulated that treated surface valleys as notches and correlated the strain localization around these notches with fatigue life, using the Coffin-Manson-Basquin and Ramberg-Osgood equations. The functional relationship was generated with the average of the extreme value distribution. The mean life curve from the functional relationship showed a maximum difference of 2 % from the experimental mean fatigue life observations for vertically built rough specimens and 10 % for 30⁰-built rough specimens. In conclusion, the proposed analytical model successfully predicted the fatigue life of L-PBF specimens at an elevated temperature undergoing different strain loadings.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104450"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423356","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":"Optimizing polymethyl methacrylate (PMMA)-based stretchable microneedle arrays by vat photopolymerization for efficient drug loading","authors":"Aqila Che Ab Rahman,&nbsp;Bum-Joo Lee,&nbsp;Sooman Lim","doi":"10.1016/j.addma.2024.104472","DOIUrl":"10.1016/j.addma.2024.104472","url":null,"abstract":"<div><div>Advancements in vat photopolymerization printing technology have enabled the fabrication of components with varying mechanical properties within a single print job. Using a digital light projector to cure photopolymer resins layer by layer, it allows the fabrication of parts with both flexibility and rigidity, in different regions. It simplifies the manufacturing process by eliminating the need for multiple steps. Specifically, for applications such as microneedles, printing onto a stretchable substrate is crucial compared to a rigid substrate, as it conforms better to the contours of the skin, ensuring more effective and comfortable drug delivery. However, a notable limitation of vat photopolymerization printing is the current lack of biocompatible materials, which restricts its application for microneedle fabrication. The challenge lies in developing materials that meet biocompatibility standards, while also being compatible with the printing technique and capable to achieve precise microscale structures. Therefore, we have developed an ultraviolet (UV)-curable polymethyl methacrylate (PMMA) suitable for the vat photopolymerization printing and the microneedles were designed to have a hollow side structure, enhancing drug loading efficiency. Comprehensive testing has been conducted, including durability test, drug loading efficiency, and skin penetration capability.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104472"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423357","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":"Carbon reduction of 3D-ink-extruded oxide powders for synthesis of equiatomic CoCuFeNi microlattices","authors":"Ya-Chu Hsu,&nbsp;Dingchang Zhang,&nbsp;David C. Dunand","doi":"10.1016/j.addma.2024.104489","DOIUrl":"10.1016/j.addma.2024.104489","url":null,"abstract":"<div><div>Equiatomic CoCuFeNi high-entropy alloy microlattices are created by 3D-extrusion printing of an ink containing a blend of binary oxides (Co₃O₄+CuO+Fe₂O₃+NiO) and graphite (C) powders. After printing, the green parts are subjected to a series of heat treatments under Ar leading to (i) carbon reduction of the oxides to form metallic particles, (ii) interdiffusion of these metallic particles to create an alloy, and (iii) sintering to remove porosity. The phase evolution in individual extruded filaments (similar to struts in the microlattices) is observed by <em>in-situ</em> X-ray diffraction, showing that intermediate suboxide phases (Cu₂O, CoO, Fe₃O₄, CuFeO₂, and FeO) form as the original oxides are reduced by carbon, before the final metallic alloy is formed. At 830 °C, the extruded filaments comprise a face-centered cubic CoCuNi(+Fe) alloy with unreduced FeO inclusions. After reduction and sintering at 1100 °C, homogeneous, densified, equiatomic CoCuFeNi microlattices are achieved, containing small amounts of a Cu-rich phase. At room temperature, the compressive strength of these CoCuFeNi microlattices increases as the strut diameter decreases from ∼260 to ∼130 µm, as expected from an observed drop in strut porosity resulting from more complete sintering. This is consistent with the easier escape of CO+CO₂ gas created during carbothermic oxide reduction from the thinner struts undergoing reduction and sintering.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104489"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533982","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":"Multi-physics simulation for predicting surface roughness of laser powder bed fused parts after laser polishing","authors":"Dac-Phuc Pham ,&nbsp;Hong-Chuong Tran","doi":"10.1016/j.addma.2024.104486","DOIUrl":"10.1016/j.addma.2024.104486","url":null,"abstract":"<div><div>Laser powder bed fusion (L-PBF) uses a controlled laser beam to melt specific regions of a metal powder bed in a layer-by-layer fashion to fabricate parts with an intricate geometry. However, due to the stochastic nature of the L-PBF process, many defects may occur during the build process, including distortion, porosity, and high surface roughness. A poor roughness of the upper surface is frequently associated with impaired mechanical properties and a lower corrosion resistance. Thus, laser polishing (LP) is commonly employed to smooth the surface of the component following the build process. The surface finish of the polished part is dependent not only on the initial morphology of the surface, but also the processing conditions employed in the polishing process (i.e., the laser power, scanning speed, and hatching space). The surface profile is also influenced by physical phenomena such as the surface tension force, recoil pressure, and Marangoni force. The present study thus proposes an integrated framework based on discrete element method (DEM) and computational fluid dynamics (CFD) simulations which takes account of all of these factors to predict the final surface morphology and roughness of L-PBF components following LP processing. The validity of the simulation model is confirmed by comparing the calculated mean surface roughness of the polished components (<span><math><mrow><msub><mrow><mi>S</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>)</mo><mspace></mspace></mrow></math></span>with the experimental values. It is found that the maximum error of the simulation results for different initial surface morphologies and LP processing conditions is less than 6.8 %.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104486"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534043","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 bespoke gas permeability by functionally graded structures in laser-based powder bed fusion of metals","authors":"Clemens Maucher ,&nbsp;Yeonse Kang ,&nbsp;Stefan Bechler ,&nbsp;Matthias Ruf ,&nbsp;Holger Steeb ,&nbsp;Hans-Christian Möhring ,&nbsp;Fabian Hampp","doi":"10.1016/j.addma.2024.104466","DOIUrl":"10.1016/j.addma.2024.104466","url":null,"abstract":"<div><div>Permeable, media transporting, components are an integral part in numerous technical applications. In gas turbines combustors, for example, gaseous oxidizer and fuel are transported separately into the burner, where they are injected and mixed, and subsequently combusted. The mixture homogeneity strongly affects the combustion performance and emissions formation and is, amongst other, determined by the spatial distribution of fuel injection ports. In this context, porous media provide the limiting case for a spatial distribution of media-injecting pores, yet is typically associated with a high pressure drop that yields a loss in efficiency. In this study, possibilities of achieving gas permeability in additively manufactured porous structures are investigated. The objective is to selectively functionalize the permeable layers for gaseous media supply with low pressure loss and, when needed, enable a targeted mixing of different gas streams. For this purpose, a laser-based powder bed fusion process (PBF-LB/M) was used in this study. It offers the opportunity to manufacture varying porosities inside complex monolithic metal parts. To produce the porous structures and to achieve gas permeability, the effect of scan rotation angle, hatch distance, build-up direction and length of the porous specimen is investigated. Due to the high temperatures present in combustion systems, the present work utilizes Inconel 718 material. The AM gas permeable specimen are experimentally characterized by means of surface topography, micro X-ray computed tomography (µXRCT) as well as flow and pressure loss test. The results show, that the AM process parameter provide effective control parameters to adjust the permeability. The strongest effect originates from the hatch distance for a given build-up direction. Depending on the scan rotation, the flow transitions from a turbulent pipe flow to a Darcy flow as present in conventional porous media. A structured alignment and connectivity of pores can be realized as evident in the µXRCT results, surface topography and the flow measurements. Residual powder, powder adhering to the pore walls and stochastic closure of pores or channels lead to deviations and need to be considered when designing respective parts. Nonetheless, the results further show that a directional dependence of the permeability and the build-up direction can be realized and controlled. Consequently, when considering the AM build-strategy in the design of components, this directed permeability can be functionalized in the generation of gas transporting and gas mixing layers separately by adjusting the AM processing parameter.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104466"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533870","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":"Optimizing AlN hydrolysis process to fabricate coated modified powders for improving the properties of Si3N4/SiAlON ceramics prepared by Vat Photopolymerization","authors":"Wei-Kang Li ,&nbsp;Ren-Zhong Zhang ,&nbsp;Jia-Min Wu ,&nbsp;Lin Guo ,&nbsp;Wei-Hao Cai ,&nbsp;Xin Lin ,&nbsp;Hai-Sheng Xu ,&nbsp;Fen Wang ,&nbsp;Yu-Sheng Shi","doi":"10.1016/j.addma.2024.104460","DOIUrl":"10.1016/j.addma.2024.104460","url":null,"abstract":"<div><div>The preparation of complex structural parts of Si₃N₄ and its composite ceramics using conventional methods is difficult. The Vat Photopolymerization (VPP) technique is regarded as an effective method for the preparation of ceramic materials. However, due to the high absorption of ultraviolet (UV) light and high refractive index of Si₃N₄, it is challenging to realize its complex structure via VPP technique. AlN and Si₃N₄ can be compounded to form SiAlON phase, and AlN powders can be hydrolyzed to produce Al(OH)₃ that can be easily dehydrated. In this study, Si₃N₄@Al₂O₃ and AlN@Al₂O₃ powders were prepared by mixing Si₃N₄ and AlN powders by hydrolysis. Subsequently, Si₃N₄/SiAlON composite ceramics were prepared by VPP. With the addition of 10 vol% AlN, the viscosity of ceramic slurry was found to be 0.50 Pa·s. Furthermore, the curing depth was observed to reach 49.46 ± 2.15 μm at 800 mJ/cm². The sintered ceramics exhibited the formation of the excellent β-Si₃N₄/β-SiAlON phase. The relative density, bending strength, hardness, fracture toughness and thermal conductivity was determined to be 92.61 ± 2.51 %, 402.91 ± 9.61 MPa, 21.11 ± 0.61 GPa, 6.33 ± 0.25 MPa·<span><math><msup><mrow><mi>m</mi></mrow><mrow><mstyle><mrow><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></mstyle></mrow></msup></math></span> and 33.17 ± 1.01 W·m⁻¹·K⁻¹, respectively. This study introduces a novel approach to cladding modification of Si₃N₄ and AlN, as well as the preparation of Si₃N₄/SiAlON composite ceramics with exceptional properties via VPP.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104460"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358086","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":"Early age shrinkage mitigation and quantitative study on water loss kinetics of 3D printed foam concrete modified with superabsorbent polymers","authors":"Chao Liu ,&nbsp;Nemkumar Banthia ,&nbsp;Yifan Shi ,&nbsp;Zijian Jia ,&nbsp;Yamei Zhang ,&nbsp;Yu Chen ,&nbsp;Yuanliang Xiong ,&nbsp;Chun Chen","doi":"10.1016/j.addma.2024.104448","DOIUrl":"10.1016/j.addma.2024.104448","url":null,"abstract":"<div><div>Due to direct exposure to the environment during the printing process and after printing and its own porous characteristics, 3D printed foam concrete (3DPFC) will inevitably have a large shrinkage at early age. In this study, the early age shrinkage of 3DPFC was modified by using various dosages of superabsorbent polymer (SAP). The water loss kinetics of 3DPFC at early age were elucidated, and the mechanism influencing early age shrinkage of 3DPFC was revealed. The 8-hour total shrinkage of 3DPFC with two foam contents was reduced by 23.1% and 24.3% at most, respectively. Based on low-field nuclear magnetic transverse relaxation time, liquids in bubble liquid film, capillary pores of the matrix, and inside SAP were quantified and tracked in real time. Under exposure conditions, there exists a quantitative relationship between internal water loss variations in 3DPFC and the matrix <em>T</em>₂₁ peak water (water adsorbed by binder particles and small capillary water between particles), bubble volume fraction, and surface tension of the matrix pore solution. The early age shrinkage of 3DPFC is indeed influenced by the combined effect of water loss and bubble volume fraction.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104448"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322698","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":"Looping: Load-oriented optimized paths in non-planar geometry","authors":"Johann Kipping,&nbsp;Doran Nettig,&nbsp;Thorsten Schüppstuhl","doi":"10.1016/j.addma.2024.104426","DOIUrl":"10.1016/j.addma.2024.104426","url":null,"abstract":"<div><div>Effective material utilization in the additive manufacturing of lightweight components is of increasing importance. The Looping (Load-oriented optimized paths in non-planar geometry) method presented in this work enables the translation of desired material orientations into suitable manufacturing instructions. The desired material orientations are derived from the principal stress directions that would manifest for an isotropic material. By employing non-planar slicing, these orientations can be followed by the deposited material beads. The novel path planning algorithm combines load-orientation and path continuity. While this can be beneficial for load-oriented printing in general, it is an especially significant step for load-oriented printing of continuous fiber reinforced polymers. The ability to follow desired material orientations with continuous paths shows particularly high potential for highly anisotropic fiber reinforced polymers. The algorithms are implemented and demonstrated in a complete process chain. However, challenges remain in the optimization of the orientation and manufacturing system for fiber reinforced polymers, which are not the focus of this work. For this reason, the process chain is realized for a neat polymer. In this context, the developed method is computationally evaluated with respect to layer height, unfilled areas, manufacturing time, geometric accuracy, and physical fabrication. The continuous and load-oriented path planning algorithm is tested against a continuous contour parallel approach and planar slicing through tensile testing. The investigations show an applicability of the process chain to successfully produce complex parts with the desired load-oriented paths. The proposed algorithm shows an increase in mechanical performance compared to the contour parallel approach highlighting its potential for non-planar printing. However, it is also found that limitations of the non-planar manufacturing process still limit its potential to surpass optimally oriented planar printing for the investigated geometry.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104426"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423469","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":"Vat photopolymerization based digital light processing 3D printing hydrogels in biomedical fields: Key parameters and perspective","authors":"Zhe Lu ,&nbsp;Weizi Gao ,&nbsp;Fukang Liu,&nbsp;Jingjing Cui,&nbsp;Shiwei Feng,&nbsp;Chen Liang,&nbsp;Yunlong Guo,&nbsp;Zhenxiang Wang,&nbsp;Zhijie Mao,&nbsp;Biao Zhang","doi":"10.1016/j.addma.2024.104443","DOIUrl":"10.1016/j.addma.2024.104443","url":null,"abstract":"<div><div>Vat photopolymerization (VP) based digital light processing (DLP) 3D printing technology gains prominence in biomedical fields, particularly for creating complex tissue structures and aiding in regeneration. Hydrogels, known for their high-water content and biocompatibility, serve as an ideal material used in VP based DLP 3D printing for mimicking biological tissues. The review examines the crucial components of VP based DLP 3D printing of hydrogels in three categories: materials, including monomers and crosslinkers that make up of hydrogels; equipment, featuring various types of VP based DLP 3D printers; and printing parameters, such as light source and exposure time. The application of VP based DLP 3D printed hydrogels at different levels of biomedical field is discussed, providing an overview of the current trends and future possibilities of VP based DLP 3D printing hydrogels in biomedical science.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104443"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328285","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}