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Digital light processing based multimaterial 3D printing:challenges,solutions and perspectives
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作者 Jianxiang Cheng Shouyi Yu +1 位作者 Rong Wang Qi Ge 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第4期151-174,共24页
Multimaterial(MM)3D printing shows great potential for application in metamaterials,flexible electronics,biomedical devices and robots,since it can seamlessly integrate distinctive materials into one printed structure... Multimaterial(MM)3D printing shows great potential for application in metamaterials,flexible electronics,biomedical devices and robots,since it can seamlessly integrate distinctive materials into one printed structure.Among numerous MM 3D printing technologies,digital light processing(DLP)MM 3D printing is compatible with a wide range of materials from hydrogels to ceramics,and can print MM 3D structures with high resolution,high complexity and fast speed.This paper introduces the fundamental mechanisms of DLP 3D printing,and reviews the recent advances of DLP MM 3D printing technologies with emphasis on material switching methods and material contamination issues.It also summarizes a number of typical examples of DLP MM 3D printing systems developed in the past decade,and introduces their system structures,working principles,material switching methods,residual resin removal methods,printing steps,as well as the representative structures and applications.Finally,we provide perspectives on the directions of the further development of DLP MM 3D printing technology. 展开更多
关键词 multimaterial 3d printing digital lightprocessing multimaterial 3dstructures
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The Application of Digital Optical 3D Image Analyzer Evaskin in The Evaluation of Wrinkles
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作者 Wang Xingkai Liu Hui +3 位作者 Liu Fei Chen Bowen Wu Tao Yang Suzhen 《China Detergent & Cosmetics》 CAS 2024年第3期62-66,共5页
To verify the effectiveness of digital optical 3D image analyzer EvaSKIN in the objective and quantitative evaluation of wrinkles.A total of 115 subjects were recruited,the facial images of the subjects were collected... To verify the effectiveness of digital optical 3D image analyzer EvaSKIN in the objective and quantitative evaluation of wrinkles.A total of 115 subjects were recruited,the facial images of the subjects were collected by digital optical 3D image analyzer and manual camera,the changes of crow’s feet with age were analyzed.Pictures obtained by manual photography can be directly used for observation and preliminary grading of wrinkles.However,the requirements for evaluators are high,and the results are prone to errors,which will affect the accuracy of the evaluation.Therefore,skilled raters are needed.Compared with the manual photography method,the digital optical 3D image analyzer EvaSKIN can realize three-dimensional extraction of wrinkles,and obtain the change trend of crow’s feet with age.20~30 years old,wrinkles begin to appear slowly;wrinkles will increase rapidly at the age of 30~50;The length of 50~60 year old wrinkles is basically fixed,the wrinkles develop longitudewise,gradually widen and deepen,and the area,depth and volume increase is obvious,and the skin aging condition is intensified.the digital optical 3D image analyzer EvaSKIN realizes the 3D extraction of wrinkles,quantifies the circumference,area,average depth,maximum depth and volume of wrinkles,realizes the objective and quantitative evaluation of wrinkle state,is more accurate in the measurement of wrinkles,and provides a new instrument and method for the evaluation of wrinkles.it is a perfect and supplement to the traditional evaluation methods,and to a certain extent,it helps the research and development and evaluation institutions of cosmetics to obtain more abundant and three-dimensional data support. 展开更多
关键词 digital optical 3d image analyzer EvaSKIN skin wrinkles age quantitative evaluation
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Review of Digital Campus Construction Led by Virtual Reality Technology
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作者 Jiaxuan Tang Yalin Lin Xinmin Hu 《Journal of Electronic Research and Application》 2024年第3期148-154,共7页
In recent years,the government has issued a series of documents to promote the construction of digital campuses.This initiative serves to encourage the deep integration of information technology and intelligent techno... In recent years,the government has issued a series of documents to promote the construction of digital campuses.This initiative serves to encourage the deep integration of information technology and intelligent technology education and digital reform,the combination of virtual reality and campus management is the need for innovative thinking and economic and social development,and then better change our learning style and living environment.The construction of the digital campus is based on virtual reality technology,BIM,GIS,and three-dimensional modeling technology to provide an immersive platform for students,promote the integration of virtual reality technology and education,help teachers,students,and parents to understand all kinds of education information and resources,to achieve their interoperability.From the off-campus environment to the school teaching equipment,teachers to teaching quality certification,and learning,to extracurricular entertainment,opening ceremonies to graduation parties,to bring more efficient,convenient,and safe campus life for teachers,students,and staff in school,and break the traditional information restrictions. 展开更多
关键词 digital campus Virtual reality technology BIM GIS 3d modeling
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Application of Digital Technology in Road and Bridge Design
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作者 Bai Fan 《Journal of Architectural Research and Development》 2024年第4期92-99,共8页
With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to t... With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to today’s digital software design era.Early designers relied on hand-drawn paper design forms which was time-consuming and error-prone.Digital support for road and bridge design not only saves the design time but the design quality has also achieved a qualitative leap.This paper engages in the application of digital technology in road and bridge design,to provide technical reference for China’s road and bridge engineering design units,to promote the popularity of Civil3D and other advanced design software in the field of engineering design and development,ultimately contributing to the sustainable development of China’s road and bridge engineering. 展开更多
关键词 road and bridge design digital technology Civil3d MOdELLING Three-dimensional view Earth calculation
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Anisotropic creep behavior of soft-hard interbedded rock masses based on 3D printing and digital imaging correlation technology 被引量:1
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作者 TIAN Yun WU Fa-quan +5 位作者 TIAN Hong-ming LI Zhe SHU Xiao-yun HE Lin-kai HUANG Man CHEN Wei-zhong 《Journal of Mountain Science》 SCIE CSCD 2023年第4期1147-1158,共12页
Three-dimensional(3D)printing technology is increasingly used in experimental research of geotechnical engineering.Compared to other materials,3D layer-by-layer printing specimens are extremely similar to the inherent... Three-dimensional(3D)printing technology is increasingly used in experimental research of geotechnical engineering.Compared to other materials,3D layer-by-layer printing specimens are extremely similar to the inherent properties of natural layered rock masses.In this paper,soft-hard interbedded rock masses with different dip angles were prepared based on 3D printing(3DP)sand core technology.Uniaxial compression creep tests were conducted to investigate its anisotropic creep behavior based on digital imaging correlation(DIC)technology.The results show that the anisotropic creep behavior of the 3DP soft-hard interbedded rock mass is mainly affected by the dip angles of the weak interlayer when the stress is at low levels.As the stress level increases,the effect of creep stress on its creep anisotropy increases significantly,and the dip angle is no longer the main factor.The minimum value of the long-term strength and creep failure strength always appears in the weak interlayer within 30°–60°,which explains why the failure of the layered rock mass is controlled by the weak interlayer and generally emerges at 45°.The tests results are verified by comparing with theoretical and other published studies.The feasibility of the 3DP soft-hard interbedded rock mass provides broad prospects and application values for 3DP technology in future experimental research. 展开更多
关键词 3d printing Soft-hard interbedded rock mass digital imaging correlation technology Weak interlayer Anisotropic creep
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Digital Simulation Platform for Satellite Launch Mission Verification
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作者 ZU Yunyu ZHANG Chi +5 位作者 BU Xiangwei XU Guoguang WU Kao XU Lijie WANG Chenxi LIU Chang 《Aerospace China》 2023年第4期9-16,共8页
To simulate the satellite launch mission under a general platform which could be used in a full-digital mode as well as in a semi-physical way, is an important way to certify the mission design performance as well as ... To simulate the satellite launch mission under a general platform which could be used in a full-digital mode as well as in a semi-physical way, is an important way to certify the mission design performance as well as technical feasibilities, and it relates to complex system simulation methods such as multi-disciplinary coupling, multi-language modeling as well as interactive simulation and virtual simulation technologies. This paper introduces the design of a digital simulation platform for satellite launch mission verification.The platform has the advantages of high generality and extensibility, being easy to build up. The Functional Mockup Interface(FMI) Standard is adopted to achieve integration of multi-source models. A WebGL based 3D visual simulation tool is also adopted to implement the virtual display system which could display the rocket launch process and rocket-satellite separation with high fidelity 3D virtual scenes. A configuration tool was developed to map the 3D objects in the visual scene with simulation physical variables for complex rocket flight control mechanisms, which greatly improves the platform's generality and extensibility. Finally the real-time performance had been tested and the YL-1 launch mission was adopted to demonstrate the functions of the platform.The platform will be used to construct a digital twin system for satellite launch missions in the future. 展开更多
关键词 digital simulation platform Functional Mockup Interface satellite launch mission WebGL based 3d virtual scenes
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政府R&D补贴的技术创新效应分析--基于2009-2021年中国的经验数据
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作者 臧传琴 《山东商业职业技术学院学报》 2024年第4期1-8,共8页
政府R&D补贴既可以通过提供公共服务的方式直接作用于技术创新,也可以通过对社会资本的引导作用间接影响技术创新,其总效应取决于两种影响的方向与大小。基于2009—2021年中国的经验数据,建立了由技术创新方程和引致方程共同组成的... 政府R&D补贴既可以通过提供公共服务的方式直接作用于技术创新,也可以通过对社会资本的引导作用间接影响技术创新,其总效应取决于两种影响的方向与大小。基于2009—2021年中国的经验数据,建立了由技术创新方程和引致方程共同组成的动态模型,对政府R&D补贴的技术创新效应进行了实证分析。结果发现:持续增加的政府R&D补贴带来了国内专利授权数量的稳定增加,技术创新效应较为显著;政府R&D补贴不仅对技术创新产生了积极的直接影响,也通过引导社会资本投资于研发领域而对技术创新产生了积极的间接影响;政府R&D补贴的技术创新效应存在区域差异,中东部地区为正,而西部地区为负。提高资金使用效率、积极引导社会资本投资技术研发、努力改善欠发达地区的研发环境,无疑是提高政府R&D补贴技术创新效应的必要选择。 展开更多
关键词 r&d补贴 技术创新 直接效应 间接效应
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云南省R&D经费投入结构动态研究 被引量:1
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作者 张和平 钟翔 +1 位作者 段江涛 贺新华 《中国科技资源导刊》 2024年第1期92-99,共8页
为研究云南省“十二五”以来R&D经费投入结构变化,分析R&D经费投入现状,并与全国,东、中、西部地区及临近省份进行了对比;从资金来源和资金配置视角,运用Cobb-Douglas效用函数及其修正模型对R&D经费投入结构展开动态分析。... 为研究云南省“十二五”以来R&D经费投入结构变化,分析R&D经费投入现状,并与全国,东、中、西部地区及临近省份进行了对比;从资金来源和资金配置视角,运用Cobb-Douglas效用函数及其修正模型对R&D经费投入结构展开动态分析。结果表明:云南省R&D经费投入结构不尽合理,资金来源中政府资金占比较低且呈下降趋势,资金配置中基础研究和应用研究投入不足,与最优结构偏离程度较大。针对存在的问题,提出持续加大政府R&D经费投入力度、围绕产业链提升基础研究和应用研究比重的建议。 展开更多
关键词 r&d经费 政府r&d投入 资源配置 活动类型 云南省 Cobb-douglas效用函数
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R&D资本化背景下我国TFP增长率再测算 被引量:1
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作者 杜瑶 许永洪 《统计研究》 CSSCI 北大核心 2024年第1期33-45,共13页
研究与试验发展(R&D)资本对经济增长和科技创新作用日益凸显,但对于R&D资本的核算亟待完善。本文基于SNA2008和CSNA2016框架,将R&D支出作为资本形成,对我国各省份物质资本存量和R&D资本存量进行规范化测算,使用随机前... 研究与试验发展(R&D)资本对经济增长和科技创新作用日益凸显,但对于R&D资本的核算亟待完善。本文基于SNA2008和CSNA2016框架,将R&D支出作为资本形成,对我国各省份物质资本存量和R&D资本存量进行规范化测算,使用随机前沿分析法重新估算1991—2019年间的全要素生产率(TFP)增长率。研究发现:第一,我国R&D资本存量规模呈总体递增和地区聚集趋势;第二,1991—2019年间,我国广义TFP增长率年平均增幅为2.10%,对经济增长存在正向作用;第三,将TFP增长率分解为技术进步、前沿技术效率和规模效应,发现技术进步对TFP增长率的贡献最大,是推动我国TFP增长的主导力量,但却呈现逐年递减的趋势;第四,随着我国对R&D投入的不断增加与重视,R&D对我国广义TFP增长率的贡献呈现递增的趋势,R&D的贡献逐渐成为推动我国科技进步的主要力量。 展开更多
关键词 r&d资本化 r&d资本存量 TFP增长率 随机前沿分析
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政府R&D资助对OFDI逆向绿色创新的影响机制研究 被引量:1
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作者 韩先锋 刘娟 李勃昕 《运筹与管理》 CSSCI CSCD 北大核心 2024年第1期158-164,共7页
应用中国分省区层面数据并采用面板门槛模型,实证考察了政府R&D资助影响OFDI逆向绿色创新的动态效应。研究发现,OFDI对国内绿色创新产生了显著的驱动效应,但这种影响呈现出明显的先负后正的“U”型动态演化特征;政府R&D资助会... 应用中国分省区层面数据并采用面板门槛模型,实证考察了政府R&D资助影响OFDI逆向绿色创新的动态效应。研究发现,OFDI对国内绿色创新产生了显著的驱动效应,但这种影响呈现出明显的先负后正的“U”型动态演化特征;政府R&D资助会正向调节OFDI逆向绿色创新溢出,且存在最适宜于OFDI逆向绿色创新的政府R&D资助区间(0.366,0.428],过高或过低强度的政府R&D资助均会在一定程度上造成OFDI逆向绿色创新的红利损失;政府R&D资助调节下OFDI对绿色创新的动态影响具有显著时空异质性,即在时空维度上存在“激励效应”与“挤出效应”交替演化的鲜明特征。 展开更多
关键词 政府r&d资助 对外直接投资 绿色创新
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Computation of elastic properties of 3D digital cores from the Longmaxi shale 被引量:5
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作者 张文辉 符力耘 +1 位作者 张艳 金维浚 《Applied Geophysics》 SCIE CSCD 2016年第2期364-374,420,共12页
The dependence of elastic moduli of shales on the mineralogy and microstructure of shales is important for the prediction of sweet spots and shale gas production. Based on 3D digital images of the microstructure of Lo... The dependence of elastic moduli of shales on the mineralogy and microstructure of shales is important for the prediction of sweet spots and shale gas production. Based on 3D digital images of the microstructure of Longmaxi black shale samples using X-ray CT, we built detailed 3D digital images of cores with porosity properties and mineral contents. Next, we used finite-element (FE) methods to derive the elastic properties of the samples. The FE method can accurately model the shale mineralogy. Particular attention is paid to the derived elastic properties and their dependence on porosity and kerogen. The elastic moduli generally decrease with increasing porosity and kerogen, and there is a critical porosity (0.75) and kerogen content (ca. ≤3%) over which the elastic moduli decrease rapidly and slowly, respectively. The derived elastic moduli of gas- and oil-saturated digital cores differ little probably because of the low porosity (4.5%) of the Longmaxi black shale. Clearly, the numerical experiments demonstrated the feasibility of combining microstructure images of shale samples with elastic moduli calculations to predict shale properties. 展开更多
关键词 Longmaxi black shale 3d digital cores elastic properties finite-element method
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企业R&D支出费用化资本化与会计盈余管理行为选择研究——基于中国部分上市公司的经验数据
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作者 姚慧娴 徐荣 《安徽工程大学学报》 CAS 2024年第4期73-81,共9页
本文基于中国部分上市公司的数据,选取R&D支出全部费用化、全部资本化、部分资本化3个虚拟变量及R&D支出费用化金额、资本化金额用以表征R&D支出披露形式,研究上市公司R&D支出会计政策选择是否与盈余管理程度相关,进而... 本文基于中国部分上市公司的数据,选取R&D支出全部费用化、全部资本化、部分资本化3个虚拟变量及R&D支出费用化金额、资本化金额用以表征R&D支出披露形式,研究上市公司R&D支出会计政策选择是否与盈余管理程度相关,进而检验R&D支出会计处理盈余管理路径,即检验R&D支出费用化、资本化的确定依据是否受其他非准则因素影响。研究结果显示,有条件资本化会计处理可能成为管理层盈余管理手段,包括应计盈余管理和真实盈余管理。在确定R&D支出费用化金额、资本化金额及R&D支出费用化强度上,管理层除了依据会计准则,还要依据当期利润情况、所得税负、利润质量、审计成本、利润平滑和公司独立性的影响。 展开更多
关键词 r&d支出 应计盈余管理 真实盈余管理 利润平滑
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全范围头面部DR辅助摆位系统设计与实现
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作者 赵杰 吕天翎 +1 位作者 刘建强 陈阳 《东南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第3期754-760,共7页
为了辅助放射技师减少摆位错误,提出了一套完整的全范围头面部DR(digital radiography)智能辅助摆位系统.该系统以嵌入式计算平台为基础,利用RGB-D相机捕获的图像准确估计患者头部姿态,并针对不同的拍摄体位需求提供精确的摆位指导.采... 为了辅助放射技师减少摆位错误,提出了一套完整的全范围头面部DR(digital radiography)智能辅助摆位系统.该系统以嵌入式计算平台为基础,利用RGB-D相机捕获的图像准确估计患者头部姿态,并针对不同的拍摄体位需求提供精确的摆位指导.采用六维向量描述头部姿态,并开发了一个深度神经网络Effi6DNet,其能够实时从RGB图像中估计全范围的头部姿态;同时,通过三维可塑模型(3DMM)和3D头部重建技术优化头部姿态估计,达到更高的准确度.该系统结合这2种技术,并融入具体摆位要求,实现了在嵌入式平台上实时和高精度的辅助摆位功能.在多个数据集上的验证结果表明,该系统能够实时和准确识别头部姿态,提供合理的摆位指导.该系统为提高头面部DR的效率和准确性提供了一种新的智能化解决方案. 展开更多
关键词 头面部dr 辅助摆位 头部姿态估计 rGB-d图像
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Comparative Study of Radiological Changes in Hands and Feet in Patients Suffering from Early Rheumatoid Arthritis by Power Doppler Ultrasound and Direct Digital Radiography
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作者 Gargy Mondal Biswadip Ghosh +1 位作者 Manoranjan Ghosh Pampa Halder 《Open Journal of Rheumatology and Autoimmune Diseases》 2014年第1期39-42,共4页
Rheumatoid arthritis is a chronic multisystem disease of unknown cause. The characteristic feature of RA is persistent inflammatory synovitis. The natural history of disease is such that the early months of the diseas... Rheumatoid arthritis is a chronic multisystem disease of unknown cause. The characteristic feature of RA is persistent inflammatory synovitis. The natural history of disease is such that the early months of the disease are critical period during which reversible joint damage occurs. So early diagnosis of RA and appropriate drug application is the only way to save a patient from this crippling disease. In India, the cost of investigations is a significant factor for most of the patients. Ultrasonography or Power Doppler Ultra Sound (PDUS) has the advantage of being economic in spite of its sensitivity in assessing both inflammatory and destructive changes. The aim of the present study was to evaluate the diagnostic efficiency of PDUS in early rheumatoid arthritis. The study was performed with the patients attending Rheumatology Clinic. A total number of 106 patients of clinically suspected rheumatoid arthritis were studied as per selection criteria. Radiological examinations of hands were done by digital radiography and PDUS in a group of 53 patients, assessment of foot changes by PDUS and Digital Radiography were done in another similar group of 53 patients. Final diagnosis by ACR EULAR-2010 criteria is done for all the patients. The comparative study reveals that synovial vascularity as demonstrated by PDUS is much more effective in diagnosing early rheumatoid arthritis, both in hand and in feet than digital radiograph. PDUS of feet may yield earlier and better findings than hands, which is conventionally used in patients suffering from early rheumatoid arthritis. 展开更多
关键词 r.A.—r.eumatoid Arthritis PdUS—Power doppler Ultrasound d.r.—digital radiography ACr-EULAr—American College of rHEUMATOLOGY (ACr) and the European LEAGUE against rHEUMATISM (EULAr) rF—rheumatoid Factor CrP—c-reactive Protein MrI—Magnetic resonance Imaging
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Physical model test and application of 3D printing rock-like specimens to laminated rock tunnels
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作者 Yun Tian Weizhong Chen +3 位作者 Hongming Tian Xiaoyun Shu Linkai He Man Huang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第11期4625-4637,共13页
Weak structural plane deformation is responsible for the non-uniform large deformation disasters in layered rock tunnels,resulting in steel arch distortion and secondary lining cracking.In this study,a servo biaxial t... Weak structural plane deformation is responsible for the non-uniform large deformation disasters in layered rock tunnels,resulting in steel arch distortion and secondary lining cracking.In this study,a servo biaxial testing system was employed to conduct physical modeling tests on layered rock tunnels with bedding planes of varying dip angles.The influence of structural anisotropy in layered rocks on the micro displacement and strain field of surrounding rocks was analyzed using digital image correlation(DIC)technology.The spatiotemporal evolution of non-uniform deformation of surrounding rocks was investigated,and numerical simulation was performed to verify the experimental results.The findings indicate that the displacement and strain field of the surrounding layered rocks are all maximized at the horizontal bedding planes and decrease linearly with the increasing dip angle.The failure of the layered surrounding rock with different dip angles occurs and extends along the bedding planes.Compressive strain failure occurs after excavation under high horizontal stress.This study provides significant theoretical support for the analysis,prediction,and control of non-uniform deformation of tunnel surrounding rocks. 展开更多
关键词 Bedding plane Three-dimensional(3d)printing Physical model test Non-uniform deformation digital imaging correlation(dIC)
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Experimental Study on Full-Surface Buckling of Variable Curvature Cylindrical Shell Using Multi-camera 3D-DIC System
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作者 LI Xin SUN Wei 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第5期589-598,共10页
To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the o... To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the object’s entire surface from multiple angles,enabling comprehensive full-surface measurement.To increase the stitching quality,a hierarchical coordinate matching method is proposed.Initially,a 3D rigid body calibration auxiliary block is employed to track motion trajectory,which enables preliminary matching of four 3D-DIC sub-systems.Subsequently,secondary precise matching is performed based on feature points on the test specimen’s surface.Through the hierarchical coordinate matching method,the local 3D coordinate systems of each double-camera system are unified into a global coordinate system,achieving 3D surface reconstruction of the variable curvature cylindrical shell,and error analysis is conducted on the results.Furthermore,axial compression buckling experiment is conducted to measure the displacement and strain fields on the cylindrical shell’s surface.The experimental results are compared with the finite element analysis,validating the accuracy and effectiveness of the proposed multi-camera 3D-DIC measuring system. 展开更多
关键词 360°3d digital image correlation(dIC) hierarchical coordinate matching method full-field 3d deformation measurement variable curvature cylindrical shell
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Modeling Methods of 3D Model in Digital Twins 被引量:1
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作者 Ruijun Liu Haisheng Li Zhihan Lv 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第8期985-1022,共38页
To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D mode... To understand the current application and development of 3D modeling in Digital Twins(DTs),abundant literatures on DTs and 3D modeling are investigated by means of literature review.The transition process from 3D modeling to DTs modeling is analyzed,as well as the current application of DTs modeling in various industries.The application of 3D DTs modeling in the􀀀elds of smartmanufacturing,smart ecology,smart transportation,and smart buildings in smart cities is analyzed in detail,and the current limitations are summarized.It is found that the 3D modeling technology in DTs has broad prospects for development and has a huge impact on all walks of life and even human lifestyles.At the same time,the development of DTs modeling relies on the development and support capabilities of mature technologies such as Big Data,Internet of Things,Cloud Computing,Articial Intelligence,and game technology.Therefore,although some results have been achieved,there are still limitations.This work aims to provide a good theoretical support for the further development of 3D DTs modeling. 展开更多
关键词 digital twins 3d modeling smart manufacturing smart city smart buildings
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Petrographic, Geochemical and Metallogenical Context of the Geological Formations of the Goumere Region (North-East of Cote D’Ivoire): Implication to the Knowledge of Gold Mineralization
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作者 Fossou Jean-Luc Hervé Kouadio Alain Nicaise Kouamelan +1 位作者 Topka Kakeu Lionel Boya Roger Nicaise Kanga 《International Journal of Geosciences》 CAS 2024年第2期180-203,共24页
The Gouméré region is located in the North-East of Côte d’Ivoire and is located in the South-West of the Bui furrow. In order to highlight the geology of the area studied, 14 samples were taken for stu... The Gouméré region is located in the North-East of Côte d’Ivoire and is located in the South-West of the Bui furrow. In order to highlight the geology of the area studied, 14 samples were taken for studies using petrographic, geochemical and metallogenic methods. The study of macroscopic and microscopic petrography made it possible to highlight two major lithological units: 1) a volcano-plutonic unit, formed of gabbros, basalt, volcaniclastics and rhyodacite;2) a sedimentary unit (microconglomerate). From a geochemical point of view, the results obtained indicate that the plutonites are gabbro and gabbro diorite while the volcanics have compositions of basaltic andesites, rhyolite and dacites. The sediments have a litharenitic to sublitharenitic character. The metallogenic study made it possible to highlight hydrothermal alterations and metalliferous paragenesis on the formations studied. Hydrothermal alteration is characterized by the presence of carbonation, silicification, sericitization, sulfidation and to a lesser degree chloritization. Metalliferous paragenesis consists of pyrite, chalcopyrite, hematite and magnetite. 展开更多
关键词 PETrOGrAPHY GEOCHEMISTrY METALLOGENY Gouméré Côte d’Ivoire
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政府采购对企业R&D投入的影响
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作者 张士博 赵雪键 +1 位作者 岳松森 李连伟 《山东工商学院学报》 2024年第1期46-56,107,共12页
针对政府采购对企业R&D投入激励的有效性问题,基于2011—2013年中国上市中小企业政府采购数据,采用倾向得分匹配法,研究政府采购、公司内部治理与企业R&D投入之间的关系。研究结果表明,政府采购能够有效促进企业R&D投入,且... 针对政府采购对企业R&D投入激励的有效性问题,基于2011—2013年中国上市中小企业政府采购数据,采用倾向得分匹配法,研究政府采购、公司内部治理与企业R&D投入之间的关系。研究结果表明,政府采购能够有效促进企业R&D投入,且这种影响因公司治理结构的不同而表现出明显的差异;政府采购对国有性质、股权分散、股权制衡及董事会规模较小的企业R&D投入的促进效应更加显著。 展开更多
关键词 政府采购 r&d投入 公司内部治理 倾向得分匹配法
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基于Tobit模型的河南省R&D投入产出影响因素分析
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作者 王新 《河南科技》 2024年第10期144-148,共5页
【目的】科技创新能力是地区综合实力的重要标志之一,科学地识别影响科技资源投入产出的因素,是实现经济跨越式发展和可持续发展的关键。【方法】基于Tobit模型对近十年河南省R&D投入产出面板数据进行相关检验,分析得出各变量对河南... 【目的】科技创新能力是地区综合实力的重要标志之一,科学地识别影响科技资源投入产出的因素,是实现经济跨越式发展和可持续发展的关键。【方法】基于Tobit模型对近十年河南省R&D投入产出面板数据进行相关检验,分析得出各变量对河南省R&D投入产出产生的不同影响。【结果】企业研发机构投入和高水平人才比例与河南省R&D投入产出效率呈显著正相关,而政府支持力度和对外开放程度则对R&D投入产出效率的作用不显著。【结论】建议河南省通过转换政府职能、注重人才引进、加强对外交流、改善区域环境等方式,优化R&D投入产出,更好地提升科技效能。 展开更多
关键词 r&d 影响因素 TOBIT模型
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