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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

Electronic and magnetic properties of single-layer and double-layer VX_(2)(X=Cl,Br)under biaxial stress

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Chinese Physics B 2021年第10期30卷 534-540页

作者： Xing Li Yanfeng Ge Jun Li wenhui wan Yong Liu State Key Laboratory of Metastable Materials Science and Technology&Key Laboratory for Microstructural Material Physics of Hebei Province School of ScienceYanshan UniversityQinhuangdao 066004China

First-principles calculations and Monte Carlo simulations reveal that single-layer and double-layer VX_(2)(X=Cl,Br)can be tuned from antiferromagnetic(AFM)semiconductors to ferromagnetic(FM)state when biaxial tensile stress is *** ground states are all T *** biaxial tensile stress at the phase transition point of the double-layer VX_(2) is larger than that of the single-layer VX_(2).The direct band gaps can be also manipulated by biaxial tensile stress as they increases with increasing tensile stress to a critical point and then *** Neel temperature(´TN)of double-layer VX_(2) are higher than that of *** the stress increases,the TN of all materials tend to *** magnetic moment increases with the increase of biaxial tensile stress,and which become insensitive to stress after the phase transition *** research provides a method to control the electronic and magnetic properties of VX_(2) by stress,and the single-layer and double-layer VX_(2) may have potential applications in nano spintronic devices.

关键词： first-principles biaxial tensile stress phase transition magnetic properties

Topographic Mapping Capability Analysis of Moderate Resolution Imaging Camera(MoRIC)Imagery of Tianwen-1 Mars Mission

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Journal of Remote Sensing

Journal of Remote Sensing 2023年第1期3卷 198-212页

作者： Man Peng Kaichang Di Zhaoqin Liu Sheng Gou wenhui wan Yexin wang State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100101China

The Moderate Resolution Imaging Camera(MoRIC)onboard the orbiter of China’s Tianwen-1 Mars mission aims to map the surface of Mars globally and to explore its topography and *** camera’s wide field of view can be used to overlap adjacent images sufficiently for topographic *** study aimed to assess the topographic mapping potential of MoRIC images via a systematic accuracy analysis of MoRIC stereo mapping based on theoretical calculation and experimental *** analyses were conducted using digital elevation models(DEMs)based on MoRIC images covering the Zhurong rover landing area and Mars Chart 11 *** between these DEMs and reference DEMs revealed that the elevation accuracy of the former was approximately one ground sampling distance of the MoRIC image,which is consistent with the theoretical *** on these results,MoRIC can be used to effectively map the Martian surface via stereo *** results serve as a useful guideline for topographic mapping based on MoRIC images and their application in various streams of research.

关键词： mapping Camera topographic

High precision landing site mapping and rover localization for Chang'e-3 mission

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Science China(Physics,Mechanics & Astronomy) 2015年第1期58卷 139-149页

作者： LIU ZhaoQin DI KaiChang PENG Man wan wenhui LIU Bin LI LiChun YU TianYi wanG BaoFeng ZHOU JianLiang CHEN HongMin State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital Earth (RADI) Chinese Academy of Sciences Beijing Aerospace Control Center (BACC)

This paper presents the comprehensive results of landing site topographic mapping and rover localization in Chang’e-3 ***-precision topographic products of the landing site with extremely high resolutions(up to 0.05 m)were generated from descent images and registered to CE-2 *** DEM and DOM with 0.02 m resolution were produced routinely at each waypoint along the rover *** lander location was determined to be(19.51256°W,44.11884°N,-2615.451 m)using a method of DOM *** order to reduce error accumulation caused by wheel slippage and IMU drift in dead reckoning,cross-site visual localization and DOM matching localization methods were developed to localize the rover at waypoints;the overall traveled distance from the lander is 114.8 m from cross-site visual localization and 111.2 m from DOM matching *** latter is of highest accuracy and has been verified using a LRO NAC image where the rover trajeactory is directly *** CE-3 mission operations,landing site mapping and rover localization products including DEMs and DOMs,traverse maps,vertical traverse profiles were generated timely to support teleoperation tasks such as obstacle avoidance and rover path planning.

关键词： Chang'e-3 Yutu rover landing site mapping rover localization descent camera navigation camera

Progress and Applications of Visual SLAM

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Journal of Geodesy and Geoinformation Science 2019年第2期2卷 38-49页

作者： Kaichang DI wenhui wan Hongying ZHAO Zhaoqin LIU Runzhi wanG Feizhou ZHANG State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Beijing 100101 China Institute of Remote Sensing and Geographic Information System Peking University Beijing 100871 China

Visual simultaneous localization and mapping (SLAM) provides mapping and self-localization results for a robot in an unknown environment based on visual sensors, that have the advantages of small volume, low power consumption, and richness of information acquisition. Visual SLAM is essential and plays a significant role in supporting automated and intelligent applications of robots. This paper presents the key techniques of visual SLAM, summarizes the current research status, and analyses the new trends of visual SLAM research and development. Finally, specific applications of visual SLAM in restricted environments, including deep space and indoor scenarios, are discussed.

关键词： visual SLAM feature extraction Kalman filter graph based optimization loop closure detection

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

N-乙酰半胱氨酸在缺血性脑卒中的作用及机制

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中山大学学报（医学科学版） 2024年第2期45卷 190-195页

作者：杨晨万文辉中国人民解放军东部战区总医院干部病房一科江苏南京210002

缺血性脑卒中(CIS)是指因脑部血液循环障碍,缺血、缺氧所致的局限性脑组织的缺血性坏死或软化,其发病率在脑血管病中占据首位。氧气和营养供应的减少会导致神经元的严重丧失,并导致中风患者脑功能的缺陷。开发缺血性脑卒中的治疗方法仍... 详细信息

缺血性脑卒中(CIS)是指因脑部血液循环障碍,缺血、缺氧所致的局限性脑组织的缺血性坏死或软化,其发病率在脑血管病中占据首位。氧气和营养供应的减少会导致神经元的严重丧失,并导致中风患者脑功能的缺陷。开发缺血性脑卒中的治疗方法仍然是临床医学的重要挑战。抗氧化剂N-乙酰半胱氨酸(NAC)是谷胱甘肽前体物质,缺血性脑卒中动物模型及一些临床研究的证据表明,NAC可以有效地保护大脑免受缺血损伤。本文从抗氧化、抑制炎症、保护脑神经和线粒体功能、稳定动脉斑块及溶栓功能等多方面阐述NAC在CIS中的作用机制,旨在从基础层面深入探究NAC与CIS的关系,为NAC进一步应用于缺血性脑卒中患者的防治提供理论依据。

关键词： N-乙酰半胱氨酸缺血性脑卒中氧化应激炎症溶栓

利用LiDAR点云强度的十字剖分线法道路提取

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武汉大学学报（信息科学版） 2015年第12期40卷 1563-1569页

作者：黄先锋李娜张帆万文辉武汉大学测绘遥感信息工程国家重点实验室湖北武汉430079 地球空间信息协同创新中心湖北武汉430079 中国科学院遥感应用研究所北京100101

由于道路与地面在空间上表现相近,因此,仅用空间坐标无法从LiDAR数据中直接提取道路。机载激光扫描系统在获取对象三维信息的同时,也记录了激光经由反射的强度信息,因此能从空间坐标和辐射两个方面表现地物的特性。结合这两种相对独立... 详细信息

由于道路与地面在空间上表现相近,因此,仅用空间坐标无法从LiDAR数据中直接提取道路。机载激光扫描系统在获取对象三维信息的同时,也记录了激光经由反射的强度信息,因此能从空间坐标和辐射两个方面表现地物的特性。结合这两种相对独立的信息在激光扫描数据中进行道路提取,提高了提取结果的稳定性。首先利用激光扫描数据的高程滤波去除非地面点;再通过强度信息进行阈值分割得到包含干扰的初始道路区域;然后,利用两组十字剖分线检测初始区域在4个方向的狭长性与宽度一致性,使得狭长状、区域宽度较一致的道路区域同干扰区域具有不同的权值,从而提取真正的道路区域;最终通过对道路区域的细化和平滑,得到道路中心线。实验表明,该方法能够较好地在LiDAR数据中提取出道路并得到道路中心线。

关键词：激光扫描强度道路提取十字剖分线

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维生素D在脓毒症中的作用及机制

中华危重病急救医学 2019年第9期31卷 1170-1173页

作者：杨晨刘瑜万文辉东部战区总医院干部病房一二科江苏南京210002

脓毒症是宿主对感染的反应失调导致的危及生命的器官功能障碍,目前仍是危重患者死亡的主要原因之一。研究表明,危重症尤其是脓毒症患者普遍存在维生素D缺乏或不足,维生素D与脓毒症之间的关系引起了越来越多的关注。本文通过分析近年来... 详细信息

脓毒症是宿主对感染的反应失调导致的危及生命的器官功能障碍,目前仍是危重患者死亡的主要原因之一。研究表明,危重症尤其是脓毒症患者普遍存在维生素D缺乏或不足,维生素D与脓毒症之间的关系引起了越来越多的关注。本文通过分析近年来维生素D与脓毒症的相关文献,从免疫调控、炎症调节、内皮细胞保护、一氧化氮调节、受体基因多态性等多方面阐述维生素D在脓毒症中的作用及机制,以期为脓毒症的诊疗提供新思路。

关键词：维生素D 脓毒症免疫调控炎症反应