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Biomimetic 3D printing of composite structures with decreased cracking

NANOTECHNOLOGY AND PRECISION ENGINEERING 2024年第3期7卷 24-34页

作者： Du, Fan Li, Kai Li, Mingzhen Fang, Junyang Sun, Long wang, Chao wang, yexin Liu, Maiqi Li, Jinbang wang, Xiaoying Ningbo Univ Sch Mech Engn & Mech Ningbo 315211 Peoples R China China Univ Min & Technol Sch Mech & Elect Engn Xuzhou 221116 Peoples R China Ningbo Univ Inst Adv Energy Storage Technol & Equipment Ningbo 315211 Peoples R China Ningbo Univ Sch Civil & Environm Engn & Geog Sci Ningbo Peoples R China

The development of tissue engineering and regeneration research has created new platforms for bone transplantation. However, the preparation of scaffolds with good fiber integrity is challenging, because scaffolds prepared by traditional printing methods are prone to fiber cracking during solvent evaporation. Human skin has an excellent natural heat-management system, which helps to maintain a constant body temperature through perspiration or blood-vessel constriction. In this work, an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was developed. In this system, the evaporation of solvent in the printed fibers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural integrity. To investigate the solvent evaporation and the interlayer bonding of the fibers, finite-element analysis simulations of a three-layer microscale structure were carried out. The results show that the solvent-evaporation path is from bottom to top, and the strain in the printed structure becomes smaller with a smaller temperature-change rate. Experimental results verified the accuracy of these simulation results, and a variety of complex 3D structures with high aspect ratios were printed. Microscale cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5 degree celsius s(-1). Optimized process parameters were selected to prepare a tissue engineering scaffold with high integrity. It was confirmed that this printed scaffold had good biocompatibility and could be used for bone-tissue regeneration. This simple and flexible 3D-printing method can also help with the preparation of a wide range of micro- and nanostructured sensors and actuators. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://***/licenses/by/4.0/).

关键词： 3D printing Electrohydrodynamic jet Biomimetic Structural integrity Composite scaffold SCAFFOLDS OSTEOPOROSIS

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椎管内肿瘤术后患者早期功能康复相关影响因素分析

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现代肿瘤医学 2024年第4期32卷 708-713页

作者：李庆伟王叶新齐豹孟纯阳济宁医学院附属医院脊柱外科山东济宁272100

目的:探讨椎管内肿瘤术后患者早期功能康复相关影响因素,提高临床疗效。方法:回顾性分析2018年12月至2022年11月我院80例椎管内肿瘤患者临床资料,其中男性39例,女性41例,年龄25~73岁,平均年龄(51.33±11.71)岁。利用SPSS 25.0软件进行... 详细信息

目的:探讨椎管内肿瘤术后患者早期功能康复相关影响因素,提高临床疗效。方法:回顾性分析2018年12月至2022年11月我院80例椎管内肿瘤患者临床资料,其中男性39例,女性41例,年龄25~73岁,平均年龄(51.33±11.71)岁。利用SPSS 25.0软件进行统计分析,首先对所有变量按相应检验方法进行单因素分析,再将单因素分析统计中有显著性差异(P<0.05)的指标进行多因素Logistic回归分析,得出可能影响椎管内肿瘤术后患者早期功能康复的独立危险因素。结果:单因素分析显示,视觉模拟(VAS)评分(P=0.042)、Oswestry功能障碍指数(ODI)(P=0.046)、营养状况(P=0.019)、内固定物(P=0.000)、手术方式(P=0.000)、脑脊液漏(P=0.033)、椎管内肿瘤部位(P=0.000)、留置管路(P=0.044)、脊神经功能(P=0.049)、糖尿病(P=0.048)、肢体肌力(P=0.002)差异均有统计学意义;Logistic回归分析显示,VAS评分(P=0.039)、ODI(P=0.025)、内固定物(P=0.016)、手术方式(P=0.037)、椎管内肿瘤部位(P=0.004)、留置管路(P=0.028)、脊神经功能(P=0.049)差异均有统计学意义。结论:VAS评分、ODI、营养状况、内固定物、手术方式、脑脊液漏、椎管内肿瘤部位、留置管路、脊神经功能、糖尿病、肢体肌力均为椎管内肿瘤术后患者早期功能康复的影响因素;其中VAS评分、ODI、内固定物、手术方式、椎管内肿瘤部位、留置管路、脊神经功能为该类患者早期功能康复的独立影响因素。

关键词：椎管内肿瘤早期功能康复手术治疗影响因素

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嫦娥六号着陆点高精度视觉定位

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遥感学报 2024年第6期28卷 1648-1655页

作者：刘召芹彭嫚邸凯昌万文辉刘斌王晔昕谢彬寇玉珂王彪赵晨旭张一凡中国科学院空天信息创新研究院遥感与数字地球重点实验室北京100101 中国科学院大学北京100049

嫦娥六号着陆点的精确定位对于工程任务顺利实施和科学研究至关重要。本文基于嫦娥二号正射影像、月球勘测轨道器窄角相机正射影像、嫦娥六号降落相机图像等数据,利用图像仿真和特征匹配方法确定了嫦娥六号着陆点在嫦娥二号正射影像的... 详细信息

嫦娥六号着陆点的精确定位对于工程任务顺利实施和科学研究至关重要。本文基于嫦娥二号正射影像、月球勘测轨道器窄角相机正射影像、嫦娥六号降落相机图像等数据,利用图像仿真和特征匹配方法确定了嫦娥六号着陆点在嫦娥二号正射影像的精确位置为(153.9780°W,41.6252°S),同时确定了在LROC NAC正射影像中的精确位置。嫦娥六号着陆点精确定位结果直接支持了工程任务的实施,对于结合着陆区高精度地形和嫦娥六号样品深入开展着陆区科学研究具有重要支撑作用。

关键词：遥感嫦娥六号视觉定位降落相机图像图像仿真图像匹配

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Geospatial technologies for Chang’e-3 and Chang’e-4 lunar rover missions

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Geo-Spatial Information Science 2020年第1期23卷 87-97页

作者： Kaichang Di Zhaoqin Liu Wenhui Wan Man Peng Bin Liu yexin wang Sheng Gou Zongyu Yue State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingChina

This paper presents a brief overview of the geospatial technologies developed and applied in Chang’e-3 and Chang’e-4 lunar rover *** mapping techniques were used to produce topographic products of the landing site with meter level resolution using orbital images before landing,and to produce centimeter-resolution topographic products in near real-time after *** positioning techniques were used to determine the locations of the two landers using descent images and orbital basemaps immediately after *** surface operations,visual-positioning-based rover localization was performed routinely at each waypoint using Navcam *** topographic analysis and rover localization results directly supported waypoint-to-waypoint path planning,science target selection and scientific investigations.A GIS-based digital cartography system was also developed to support rover teleoperation.

关键词： Geospatial technology lunar rover landing site mapping topographic analysis rover localization and navigation

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Mapping out the reaction network of humin formation at the initial stage of fructose dehydration in water

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Green Energy & Environment 2024年第6期9卷 1016-1026页

作者： Xing Fu yexin Hu Ping Hu Hui Li Shuguang Xu Liangfang Zhu Changwei Hu Key Laboratory of Green Chemistry and Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengduSichuan610064China State Key Laboratory of Southwestern Chinese Medicine Resources Innovative Institute of Chinese Medicine and PharmacyChengdu University of Traditional Chinese MedicineChengduSichuan611137China

The formation of humins hampers the large-scale production of 5-hydroxymethylfurfural(HMF)in ***,a detailed reaction network of humin formation at the initial stage of fructose-to-HMF dehydration in water is delineated by combined experimental,spectroscopic,and theoretical *** bimolecular reaction pathways to build up soluble humins are *** is,the intermolecular etherification of β-furanose at room temperature initiates the C12 path,whereas the C-C cleavage of a-furanose at 130-150℃ leads to C11 path,and that of open-chain fructose at 180℃ to C11' *** successive intramolecular dehydrations and condensations of the as-formed bimolecular intermediates lead to three types of soluble *** show that the C12 path could be restrained by using HCl or AlCl_(3) catalyst,and both the C12 and C110 paths could be effectively inhibited by adding THF as a co-solvent or accelerating heating rate via microwave heating.

关键词： Carbohydrates 5-hydroxymethylfurfural Reaction network Soluble humins Tautomer

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Landing site topographic mapping and rover localization for Chang'e-4 mission

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Science China(Information Sciences) 2020年第4期63卷 170-181页

作者： Zhaoqin LIU Kaichang DI Jian LI Jianfeng XIE Xiaofeng CUI Luhua XI Wenhui WAN Man PENG Bin LIU yexin wang Sheng GOU Zongyu YUE Tianyi YU Lichun LI Jia wang Chuankai LIU Xin XIN Mengna JIA Zheng BO Jia LIU Runzhi wang Shengli NIU Kuan ZHANG Yi YOU Bing LIU Jiangang LIU State Key Laboratory of Remote Sensing Science Aerospace Information Research Institute Chinese Academy of Sciences Beijing Aerospace Control Center (BACC)

This paper presents the techniques and results of landing-site topographic mapping and rover localization using orbital, descent and rover images in the Chang’e-4 mission. High-resolution maps of the landing site are generated from orbital and descent images. Local digital elevation models and digital orthophoto maps with 0.02 m resolution are generated at each waypoint. The location of the lander is determined as(177.588° E, 45.457°S) using festure-matching techniques. The cross-site visual localization method is routinely used to localize the rover at each waypoint to reduce error accumulation from wheel slippage and IMU drift in dead reckoning. After the first five lunar days, the rover travels 186.66 m from the lander, according to the cross-site visual localization. The developed methods and results have been directly utilized to support the mission’s operations. The maps and localization information are also valuable for supporting multiple scientific explorations of the landing site.

关键词： Chang’e-4 Yutu-2 rover landing site mapping rover localization descent images rover images

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Numerical multi-physical optimization of operating condition and current collecting setup for large-area solid oxide fuel cells

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Frontiers in Energy 2024年第3期18卷 356-368页

作者： Chengrong YU Zehua PAN Hongying ZHANG Bin CHEN Wanbing GUAN Bin MIAO Siew Hwa CHAN Zheng ZHONG yexin ZHOU School of Science Harbin Institute of TechnologyShenzhen 518055China Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyShenzhen UniversityShenzhen 518060China Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and Engineering of the Chinese Academy of SciencesNingbo 315201China Energy Research Institute at NTU(ERIAN) Nanyang Technological UniversitySingapore 639798Singapore

Due to the depletion of traditional fossil fuels and the aggravation of related environmental problems,hydrogen energy is gaining more attention all over the *** oxide fuel cell(SOFC)is a promising power generation technology operating on hydrogen with a high *** further boost the power output of a single cell and thus a single stack,increasing the cell area is an effective ***,it was recently found that further increasing the effective area of an SOFC single cell with a flat-tubular structure and symmetric double-sided cathodes would result in a lower areal *** this work,a multi-physical model is built to study the effect of the effective area on the cell *** distribution of different physical fields is systematically *** of the cell performance is also pursued by systematically tuning the cell operating condition and the current collection *** improvement of 42%is revealed by modifying the inlet gas flow rates and by enhancing the current *** the future,optimization of cell geometry will be performed to improve the homogeneity of different physical fields and thus to improve the stability of the cell.

关键词： solid oxide fuel cell(SOFC) large effective area flow rate discharge performance current collection

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镜像双目视觉精密测量技术综述

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光学学报 2018年第8期38卷 51-59页

作者：周富强王晔昕柴兴华陈昕北京航空航天大学仪器科学与光电工程学院北京100191 中国科学院遥感与数字地球研究所遥感科学国家重点实验室北京100101 中国电子科技集团公司第五十四研究所航天信息应用技术重点实验室河北石家庄050081

综述了镜像双目视觉测量技术的发展现状,从测量原理及传感器、测量模型及标定、测量精度及评价等方面分析了镜像双目视觉测量结构模型,主要包括基于平面折反射的镜像双目结构和基于曲面折反射的镜像双目结构,总结了现有镜像双目测量结... 详细信息

综述了镜像双目视觉测量技术的发展现状,从测量原理及传感器、测量模型及标定、测量精度及评价等方面分析了镜像双目视觉测量结构模型,主要包括基于平面折反射的镜像双目结构和基于曲面折反射的镜像双目结构,总结了现有镜像双目测量结构在结构模型、图像获取和对应匹配等方面的优缺点,阐述了镜像双目视觉精密测量技术的发展趋势。

关键词：机器视觉双目视觉精密测量折反射

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An Automatic System of Vehicle Number-Plate Recognition Based on Neural Networks

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Journal of Systems Engineering and Electronics 2001年第2期12卷 63-72页

作者： Wei Wu Dept. of Road and Traffic Engineering, Changsha Communications University, 410076, P. R. China Huang Xinhan, wang Min & Song yexin Dept. of Control Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China Dept. of Road and Traffic Engineering Changsha Communications University 410076 P. R. China Dept. of Control Science and Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China

This paper presents an automatic system of vehicle number-plate recognition based on neural networks. In this system, location of number-plate and recognition of characters in number-plate can be automatically completed. Pixel colors of Number-plate area are classified using neural network, then color features are extracted by analyzing scanning lines of the cross-section of number-plate. It takes full use of number-plate color features to locate number-plate. Characters in number-plate can be effectively recognized using the neural networks. Experimental results show that the correct rate of number-plate location is close to 100%, and the time of number-plate location is less than 1 second. Moreover, recognition rate of characters is improved due to the known number-plate type. It is also observed that this system is not sensitive to variations of weather, illumination and vehicle speed. In addition, and also the size of number-plate need not to be known in prior. This system is of crucial significance to apply and spread the automatic system of vehicle number-plate recognition.

关键词： Cameras Charge coupled devices Feature extraction Neural networks Vehicles

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行星遥感影像目标识别与分类进展

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遥感学报 2021年第1期25卷 365-380页

作者：邸凯昌叶乐佳王润之王晔昕中国科学院空天信息创新研究院遥感科学国家重点实验室北京100101 中国科学院大学北京100049

从行星遥感海量数据中对地形地貌特征进行识别和分类,是行星科学研究中的一项重要基础工作。本文综述了自实施月球和深空探测任务以来,国际、国内采用行星影像数据进行地形地貌识别与分类技术的研究进展。首先,从月球、火星以及其他行... 详细信息

从行星遥感海量数据中对地形地貌特征进行识别和分类,是行星科学研究中的一项重要基础工作。本文综述了自实施月球和深空探测任务以来,国际、国内采用行星影像数据进行地形地貌识别与分类技术的研究进展。首先,从月球、火星以及其他行星探测任务3个方面,对相关的探测任务和获取的影像数据进行简介。然后,在介绍通用目标识别与分类方法研究进展的基础上,分别详细阐述了月球、火星、其他行星影像数据的目标识别与分类研究进展,具体包括:(1)在月球影像目标识别与分类研究进展中,从月球表面环形构造识别,线性构造识别,以及地形分类几个方面展开详述;(2)在火星影像目标识别与分类研究进展中,从构造地貌,风成地貌,水成地貌,其他地貌的识别与地形分类几个方面的研究进展进行详述;(3)其他行星影像目标识别与分类研究进展中,从太阳系的其他类地行星和小行星的影像目标识别与地形分类研究进展进行阐述,其中针对小行星近距离飞越探测、绕飞探测、附着就位探测和表面采样返回等探测方式,分别介绍了对其影像数据的目标识别与地形分类的研究进展。最后,对行星遥感影像目标识别和分类技术的未来发展方向进行了展望和探讨。

关键词：行星探测遥感数据目标识别地形分类机器学习

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