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Data Logic Structure and Key Technologies on Intelligent High-precision Map 被引量:12
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作者 Jingnan LIU Jiao ZHAN +2 位作者 Chi GUO Tingting LEI Ying LI 《Journal of Geodesy and Geoinformation Science》 2020年第3期1-17,共17页
Taking autonomous driving and driverless as the research object,we discuss and define intelligent high-precision map.Intelligent high-precision map is considered as a key link of future travel,a carrier of real-time p... Taking autonomous driving and driverless as the research object,we discuss and define intelligent high-precision map.Intelligent high-precision map is considered as a key link of future travel,a carrier of real-time perception of traffic resources in the entire space-time range,and the criterion for the operation and control of the whole process of the vehicle.As a new form of map,it has distinctive features in terms of cartography theory and application requirements compared with traditional navigation electronic maps.Thus,it is necessary to analyze and discuss its key features and problems to promote the development of research and application of intelligent high-precision map.Accordingly,we propose an information transmission model based on the cartography theory and combine the wheeled robot’s control flow in practical application.Next,we put forward the data logic structure of intelligent high-precision map,and analyze its application in autonomous driving.Then,we summarize the computing mode of“Crowdsourcing+Edge-Cloud Collaborative Computing”,and carry out key technical analysis on how to improve the quality of crowdsourced data.We also analyze the effective application scenarios of intelligent high-precision map in the future.Finally,we present some thoughts and suggestions for the future development of this field. 展开更多
关键词 intelligent high-precision map information transmission model data logic structure user model computing mode edge-cloud collaboration
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Developing High-Precision Maps for Automated Driving in China:Legal Obstacles and the Way to Overcome Them 被引量:1
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作者 ZHANG Taolue TU Huizhao QIU Wei 《Journal of Shanghai Jiaotong university(Science)》 EI 2021年第5期658-669,共12页
A high-precision map(HPM)is the key infrastructure to realizing the function of automated driving(AD)and ensuring its safety.However,the current laws and regulations on HPMs in China can lead to serious legal complian... A high-precision map(HPM)is the key infrastructure to realizing the function of automated driving(AD)and ensuring its safety.However,the current laws and regulations on HPMs in China can lead to serious legal compliance problems.Thus,proper measures should be taken to remove these barriers.Starting with a complete view of the current legal obstacles to HPMs in China,this study first explains why these legal obstacles exist and the types of legal interests they are trying to protect.It then analyzes whether new technology could be used as an alternative to resolve these concerns.Factors such as national security,AD industry needs,and personal data protection,as well as the flexibility of applying technology,are discussed and analyzed hierarchically for this purpose.This study proposes that China should adhere to national security and AD industry development,pass new technical regulations that redefine the scope of national security regarding geographic information in the field of HPMs,and establish a national platform under the guidance and monitoring of the government to integrate scattered resources and promote the development of HPMs via crowdsourcing.Regarding the legal obstacles with higher technical plasticity,priority should be given to technical solutions such as“available but invisible”technology.Compared with the previous research,this study reveals the current legal barriers in China that have different levels of relevance to national security and different technical plasticity.It also proposes original measures to remove them,such as coordinating national security with the development of the AD industry,reshaping the boundary of national security and industrial interests,and giving priority to technical solutions for legal barriers that have strong technical plasticity. 展开更多
关键词 automated driving(AD) navigation electronic map(NEM) high-precision map(HPM) surveying and mapping national security “available but invisible”technology
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Study on Characteristics of a High-Precision Cold Gas Micro Thruster
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作者 Zhaoli Wang Changbin Guan +2 位作者 Xudong Wang Weijie Zheng Longfei Su 《Engineering(科研)》 2024年第1期38-45,共8页
In order to improve the reliability of the spacecraft micro cold gas propulsion system and realize the precise control of the spacecraft attitude and orbit, a micro-thrust, high-precision cold gas thruster is carried ... In order to improve the reliability of the spacecraft micro cold gas propulsion system and realize the precise control of the spacecraft attitude and orbit, a micro-thrust, high-precision cold gas thruster is carried out, at the same time due to the design requirements of the spacecraft, this micro-thrust should be continuous working more than 60 minutes, the traditional solenoid valve used for the thrusts can’t complete the mission, so a long-life micro latching valve is developed as the control valve for this micro thruster, because the micro latching valve can keep its position when it cuts off the outage. Firstly, the authors introduced the design scheme and idea of the thruster. Secondly, the performance of the latching valve and the flow characteristics of the nozzle were simulated. Finally, from the experimental results and compared with the numerical study, it shows that the long-life micro cold gas thruster developed in this paper meets the mission requirements. 展开更多
关键词 high-precision Micro Thruster Performance Flow Characteristic EXPERIMENT
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High-Precision Structural Map of Southeast Cameroon Using Phase Filters on Potential Gravimetric Data
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作者 Nzeuga Alain Rodrigue Bisse Salomon Bertrant +7 位作者 Amaya Adama Kenfack Fokem Alpha Baster Ngah Christian Gislain Leonel Ndjounguep Juscar Nanfa Tefak Fatoumata Maelle Ngoumou Paul Claude Assembe Stéphane Patrick Pokam Kengni Serge Hugues 《Open Journal of Earthquake Research》 2022年第4期89-107,共19页
The south-east of Cameroon encompasses a wide variety of geological structures among which we can cite the Congo Craton (CC), the Sanaga Fault (SF), the Yaoundé Domain, the Panafrican belt, the Protozoic series a... The south-east of Cameroon encompasses a wide variety of geological structures among which we can cite the Congo Craton (CC), the Sanaga Fault (SF), the Yaoundé Domain, the Panafrican belt, the Protozoic series and the Dja complex. The presence of all these structures justifies the great tectonic activity to which this area was subject from the rupture of Pangea to the creation of the different plates that exist today. In this work, we will bring out a high-resolution structural map of the study area by applying the qualitative analysis of the phase filters on 200,900 points of gravimetric data obtained from the combination of the XGM2016 and ETOPO1 models. Then, with these same data, we will bring out another structural map with the maxima method called Multi-Scale Horizontal Derivative of Vertical Derivative (MSHDVD) which will be compared to the first in order to show the limits of the MSHDVD method. To do this, we will first use the extension method to highlight the map of residual anomalies, then a combination of derivative, gradient and phase filters to highlight the geological structures responsible for fracturing in this area. Phase filters have the advantage that they make it possible to highlight all the geological edges responsible for the fracturing without taking into account the depth, while the MSHDVD method highlights the existing geological contacts (edges) at depths well defined by the examiner. The structural map obtained with the MSHDVD method shows that the major structural direction in this zone is W-E while that obtained from the interpretation of the phase filters is more precise and shows that the major structural direction in this area would be N-S and this result would be in perfect agreement with the tectonics of East Cameroon. 展开更多
关键词 GRAVIMETRY Potential Field Data Edge Detection Structural mapping Southeast Cameroon
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High-precision automatic measurement of two-dimensional geometric features based on machine vision 被引量:6
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作者 何博侠 何勇 +1 位作者 薛蓉 杨洪锋 《Journal of Southeast University(English Edition)》 EI CAS 2012年第4期428-433,共6页
To realize high-precision automatic measurement of two-dimensional geometric features on parts, a cooperative measurement system based on machine vision is constructed. Its hardware structure, functional composition a... To realize high-precision automatic measurement of two-dimensional geometric features on parts, a cooperative measurement system based on machine vision is constructed. Its hardware structure, functional composition and working principle are introduced. The mapping relationship between the feature image coordinates and the measuring space coordinates is established. The method of measuring path planning of small field of view (FOV) images is proposed. With the cooperation of the panoramic image of the object to be measured, the small FOV images with high object plane resolution are acquired automatically. Then, the auxiliary measuring characteristics are constructed and the parameters of the features to be measured are automatically extracted. Experimental results show that the absolute value of relative error is less than 0. 03% when applying the cooperative measurement system to gauge the hole distance of 100 mm nominal size. When the object plane resolving power of the small FOV images is 16 times that of the large FOV image, the measurement accuracy of small FOV images is improved by 14 times compared with the large FOV image. It is suitable for high-precision automatic measurement of two-dimensional complex geometric features distributed on large scale parts. 展开更多
关键词 machine vision two-dimensional geometric features high-precision measurement automatic measurement
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融合Mind Map优势助力完善线上线下教学衔接--以园林树木学树种识别教学为例 被引量:1
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作者 刘艺平 贺丹 +1 位作者 李永华 张曼 《高教学刊》 2024年第1期78-81,共4页
疫情当前,线上线下混合式教学已经成为课程教学新模式。树种识别是园林树木学教学的重点和难点,也是教学目的之一。由于课程涉及的树种种类繁多,知识点琐碎,专业术语抽象,再加上课时少任务重,使得教师在教学过程中无法将所有树种的特征... 疫情当前,线上线下混合式教学已经成为课程教学新模式。树种识别是园林树木学教学的重点和难点,也是教学目的之一。由于课程涉及的树种种类繁多,知识点琐碎,专业术语抽象,再加上课时少任务重,使得教师在教学过程中无法将所有树种的特征逐一讲解到,学生在学习过程中也容易混淆,无法有效吸收知识点。因此,在课程的教学改革中,通过引入Mind Map帮助厘清知识框架,优化知识结构,搭建知识关联,不仅使教师授课过程更顺畅,而且能够激发学生在线学习的兴趣,促使学生养成“整理知识点”的良好习惯,使学习效率大幅度提高,从而创建高效的线上课堂,有效巩固混合式教学的教学效果。 展开更多
关键词 线上线下 园林树木学 Mind map 树种识别 混合式教学
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磁共振T1rho序列、T2 mapping技术在膝关节早期软骨退变早期诊断中的评估价值 被引量:1
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作者 唐毅 张辉 +1 位作者 黄恺 黎本丰 《中国CT和MRI杂志》 2024年第4期163-165,共3页
目的探讨磁共振T1rho序列、T2 mapping技术在膝关节早期软骨退变早期诊断中的评估价值。方法选取2020年1月至2022年11月在我院治疗的110例膝关节早期软骨退变患者(观察组),按照疾病严重程度分为轻度退变组及重度退变组,另选取同期在我... 目的探讨磁共振T1rho序列、T2 mapping技术在膝关节早期软骨退变早期诊断中的评估价值。方法选取2020年1月至2022年11月在我院治疗的110例膝关节早期软骨退变患者(观察组),按照疾病严重程度分为轻度退变组及重度退变组,另选取同期在我院进行体检的64例健康者为对照组,受试者均行磁共振T1rho序列、T2 mapping技术扫描,测量受试者T2值及T1ρ值,探讨磁共振T1rho序列、T2 mapping技术在膝关节早期软骨退变早期诊断中的评估价值。结果观察组股骨外侧面、股骨内侧面、胫骨外侧面、胫骨内侧面、髋骨面T2值均明显高于对照组(P<0.05),重度退变亚组患者股骨外侧面、股骨内侧面、胫骨外侧面、胫骨内侧面、髋骨面T2值显著高于轻度退变者(P<0.05);观察组股骨内踝负重区、股骨内踝非负重区、股骨外踝负重区、股骨外踝非负重区、胫骨外侧平台区、胫骨内侧平台区、髌后软骨区磁共振T1ρ值明显高于对照组(P<0.05),重度退变亚组患者股骨内踝负重区、股骨内踝非负重区、股骨外踝负重区、股骨外踝非负重区、胫骨外侧平台区、胫骨内侧平台区、髌后软骨区磁共振T1ρ值明显高于轻度退变亚组患者(P<0.05);磁共振T1rho序列在膝关节早期软骨退变中早期诊断及严重程度评估中的的诊断ROC值及特异度明显高于T2 mapping技术(P<0.05),但后者具有更高的敏感度(P<0.05)。结论磁共振T1rho序列、T2 mapping技术均能有效反映膝关节早期软骨退变中软骨组织学成分变化情况,还可为膝关节软骨退变严重程度评估提供客观依据,二者具有一定互补价值。 展开更多
关键词 磁共振T1rho序列 T2 mapping技术 膝关节 早期软骨退变 诊断
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MR T2^(*)mapping成像技术定量评价腰椎小关节炎软骨损伤 被引量:1
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作者 陈吉 张晨 +1 位作者 张濒 黄磊涛 《中国组织工程研究》 CAS 北大核心 2024年第30期4866-4870,共5页
背景:腰椎小关节炎是引起下腰痛的一个主要原因,目前主要依靠MRI进行初步定性诊断,但仍有一定漏诊、误诊的概率发生,因此MR T2^(*)mapping成像技术有望成为定量检查腰椎小关节炎软骨损伤的重要检测手段。目的:探讨MR T2^(*)mapping成像... 背景:腰椎小关节炎是引起下腰痛的一个主要原因,目前主要依靠MRI进行初步定性诊断,但仍有一定漏诊、误诊的概率发生,因此MR T2^(*)mapping成像技术有望成为定量检查腰椎小关节炎软骨损伤的重要检测手段。目的:探讨MR T2^(*)mapping成像技术在定量分析腰椎小关节炎软骨损伤退变中的应用价值。方法:收集南京医科大学第四附属医院2020年4月至2022年3月门诊或住院合并下腰痛共110例患者,设为病例组;同时招募无症状志愿者80例,设为对照组。对所有纳入对象L1-S1的小关节行3.0 T MR扫描,获取T2^(*)mapping横断位图像和T2WI图像,分别对所有小关节软骨进行Weishaupt分级及T2^(*)值测量,收集数据并行统计学分析。不同小关节Weishaupt分级之间小关节软骨T2^(*)值比较采用单因素方差分析。结果与结论:①经统计分析发现,病例组腰椎小关节软骨T2^(*)值(17.6±1.5)ms明显较对照组(21.4±1.3)ms降低,差异有显著性意义(P<0.05);②在病例组中,随着腰椎小关节Weishaupt分级增加,小关节软骨T2^(*)值也呈逐渐下降趋势,且这种差异有显著性意义(P<0.05);③提示T2^(*)mapping能够较好地显示腰椎小关节软骨损伤的早期病理变化,腰椎小关节软骨的T2^(*)值能够定量评估腰椎小关节的软骨损伤程度;T2^(*)mapping成像技术能为影像学诊断腰椎小关节炎软骨早期损伤提供很好的理论依据,具有重要的临床应用价值。 展开更多
关键词 腰椎小关节炎 T2^(*)mapping T2^(*)值 小关节软骨退变 下腰痛
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MAP添加液对冰冻解冻去甘油红细胞保存的质量影响
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作者 杨剑豪 聂晓绚 +5 位作者 张莉莉 章舜玮 杜祎 邱颖婕 马庆 徐蓓 《中国输血杂志》 CAS 2024年第6期684-689,共6页
目的观察冰冻解冻去甘油红细胞悬浮于MAP添加液中对保存效果的影响,探索最佳保存方式。方法本研究将采集后d 3的400 mL全血,离心制备成浓缩红细胞,使用ACP 215全自动血细胞仪,加入40%复方甘油溶液,置于-65℃超低温冰箱中保存30 d,解冻... 目的观察冰冻解冻去甘油红细胞悬浮于MAP添加液中对保存效果的影响,探索最佳保存方式。方法本研究将采集后d 3的400 mL全血,离心制备成浓缩红细胞,使用ACP 215全自动血细胞仪,加入40%复方甘油溶液,置于-65℃超低温冰箱中保存30 d,解冻去甘油洗涤后,等量分离成两袋,以添加0.9%氯化钠溶液为对照组;添加MAP为实验组,两组保存于2~6℃冷藏条件下,分别于0、1、3、5、7、14 d取样检测血液学参数指标、溶血指标、细胞代谢指标,观察两组在14 d保存期内的质量变化情况。结果研究发现两组红细胞在解冻去甘油后6项质控项目包括容量、血红蛋白含量、游离血红蛋白含量、白细胞残留量、甘油残留量、无菌试验的检测值均符合《全血及成分血质量要求》(GB18469-2012);压积、红细胞计数、Hb洗涤后回收率、MCV符合《冰冻红细胞质量评价指标专家共识》检测限值,血小板残留量超过检测限值(≤1%);在14 d保存期内,两组的RBC、Hct、MCV和血红蛋白含量值无统计学意义;两组游离血红蛋白、溶血率和K+值随保存时间延长而增加,分别于3、5、7、14 d;3、5、7、14 d;14 d组间有统计学意义(P<0.05),两组红细胞渗透脆性于14 d组间有统计学意义(P<0.05);两组ATP、pH值随保存时间延长而下降,分别于3、5、7 d;1、3、5、7、14 d组间有统计学意义(P<0.05)。结论悬浮于MAP添加液中的冰冻解冻去甘油红细胞可将血液保存期延长至7 d,本研究为相关标准的制定提供参考依据。 展开更多
关键词 冰冻解冻去甘油红细胞 map ACP215 保存期 血液质量控制
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番鸭VIPR1和miR-317以及MAP3K7和miR-244靶向关系的研究
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作者 李丽 辛清武 +4 位作者 章琳俐 缪中纬 朱志明 梁阿政 郑嫩珠 《中国家禽》 北大核心 2024年第6期15-19,共5页
试验旨在验证番鸭就巢相关miRNA与靶基因靶向关系。试验利用miRanda、PITA和RNAhybrid三个软件的交集预测miR-317和miR-244靶基因,构建VIPR1-pmirGLO/MAP3K7-pmirGLO野生型和突变型双荧光素酶重组载体,将miR-317/VIPR1-Wt和miR-244/MAP3... 试验旨在验证番鸭就巢相关miRNA与靶基因靶向关系。试验利用miRanda、PITA和RNAhybrid三个软件的交集预测miR-317和miR-244靶基因,构建VIPR1-pmirGLO/MAP3K7-pmirGLO野生型和突变型双荧光素酶重组载体,将miR-317/VIPR1-Wt和miR-244/MAP3K7-Wt分别共转染至鸭胚成纤维细胞,检测双荧光素酶活性。结果显示:与miR-NC组相比,miR-317/VIPR1-Wt共转染组相对荧光值显著降低(P<0.05);VIPR1突变后,miR-NC组与miR-317组的相对荧光值不显著(P>0.05),说明突变后完全抑制miR-317对VIPR1的结合作用,VIPR1与miR-317之间存在相互结合作用。与miR-NC组相比,miR-244/MAP3K7-Wt共转染组相对荧光值无显著性差异(P>0.05);MAP3K7突变后,miR-NC组与miR-244组的相对荧光值差异不显著(P>0.05),表明MAP3K7与miR-244之间不存在相互结合作用。研究提示,miR-317与VIPR1存在确切靶向结合位点,即VIPR1是miRNA miR-317的靶基因,而miR-244与MAP3K7不存在靶向关系。 展开更多
关键词 番鸭 就巢 miR-317 miR-244 map3K7 VIPR1
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Coordinate unification method of high-precision composite measurement in two dimensions 被引量:1
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作者 文信 付鲁华 +2 位作者 赵炎 张恒 王仲 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第3期205-213,共9页
Multi-sensor coordinate unification in dimensional metrology is used in order to get holistic, more accurate and reliable information about a workpiece based on several or multiple measurement values from ... Multi-sensor coordinate unification in dimensional metrology is used in order to get holistic, more accurate and reliable information about a workpiece based on several or multiple measurement values from one or more sensors. Because of the problem that standard ball is deficient as a standard artifact in the coordinate unification of high-precision composite measurement in two dimensions (2D) , a new method is proposed in this paper which uses angle gauge blocks as standard artifacts to achieve coordinate unification between the image sensor and the tactile probe. By comparing the standard ball with the angle gauge block as a standard artifact, theoretical analysis and experimental results are given to prove that it is more precise and more convenient to use angle gauge blocks as standard artifacts to achieve coordinate unification of high-precision composite measurement in two dimensions. 展开更多
关键词 high-precision composite measurement image sensor tactile probe coordinate unification angle gauge block
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传统武术套路训练对大学生武术运动员膝关节软骨影响的T2-mapping功能磁共振成像研究 被引量:2
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作者 邓成虎 王晨宇 +3 位作者 冉君 章瑶 李小明 夏薇 《影像科学与光化学》 CAS 2024年第3期219-225,共7页
目的:本研究旨在通过T2-mapping功能磁共振影像学技术对大学生武术运动员膝关节软骨进行定量评估,探究传统武术套路训练对大学生武术运动员膝关节软骨的影响。方法:选取9名年龄介于18~25岁之间的大学生武术运动员作为实验组,同时选取18... 目的:本研究旨在通过T2-mapping功能磁共振影像学技术对大学生武术运动员膝关节软骨进行定量评估,探究传统武术套路训练对大学生武术运动员膝关节软骨的影响。方法:选取9名年龄介于18~25岁之间的大学生武术运动员作为实验组,同时选取18名普通健康的大学生作为对照组。在相同条件下,对两组分别进行右膝关节的T2-mapping磁共振检查,并将膝关节软骨分为股骨内侧髁、胫骨内侧髁、髌软骨、股骨外侧髁及胫骨外侧髁5个感兴趣区,比较实验组与对照组之间T2值的差异,分析各组膝关节软骨不同感兴趣区T2值的变化。结果:(1)不论性别,实验组和对照组各个膝关节面软骨感兴趣区的T2值均未见显著性差异(P>0.05);(2)男性对照组、女性对照组以及女性实验组的膝关节各感兴趣区T2值两两之间均无统计学差异(P>0.05);(3)男性实验组膝关节股骨外侧髁与胫骨内侧髁、髌软骨的T2值差异具有统计学意义(P<0.05)。结论:T2-mapping技术可通过无创手段定量评估传统武术套路训练对大学生膝关节软骨的影响。在长期传统武术套路训练后,男性大学生武术运动员的膝关节出现了异质性改变,因此在训练过程中应该注意调整方案,以实现针对性保护。 展开更多
关键词 传统武术套路 大学生 膝关节 软骨 T2-mapping 磁共振成像
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DWI联合T2 mapping序列鉴别前列腺癌与前列腺增生价值评估 被引量:2
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作者 李茜玮 陈丽华 +2 位作者 王楠 林良杰 刘爱连 《磁共振成像》 CAS CSCD 北大核心 2024年第2期97-102,共6页
目的探讨扩散加权成像(diffusion-weighted imaging,DWI)联合T2 mapping序列鉴别前列腺癌(prostate cancer,PCa)与前列腺增生(benign prostatic hyperplasia,BPH)的价值。材料与方法回顾性分析本院行3.0 T MRI检查且经病理证实的56例PC... 目的探讨扩散加权成像(diffusion-weighted imaging,DWI)联合T2 mapping序列鉴别前列腺癌(prostate cancer,PCa)与前列腺增生(benign prostatic hyperplasia,BPH)的价值。材料与方法回顾性分析本院行3.0 T MRI检查且经病理证实的56例PCa患者及40例BPH患者资料。扫描序列包括T1WI、T2WI、DWI及T2 mapping序列。两名观察者分别测量两组病灶的表观扩散系数(apparent diffusion coefficient,ADC)值及T2值。采用组内相关系数(intra-class correlation coefficient,ICC)评估两名观察者测得参数值的一致性。采用独立样本t检验或Mann-Whitney U检验分析两组病例间ADC值及T2值的差异。Logistic回归用于分析差异具有统计学意义的参数及其与基线资料联合的诊断模型。采用受试者工作特征(receiver operating characteristic,ROC)曲线评估有差异参数及联合模型的诊断效能。采用DeLong检验比较ROC曲线下面积差异。采用Spearman相关系数分析ADC值与T2值相关性。结果两名观察者测量值一致性好(ICC>0.75)。PCa组的ADC值及T2值分别低于BPH组,差异具有统计学意义(P<0.01)。ADC值、T2值、ADC-T2及ADC-T2-年龄-总前列腺特异性抗原(total prostate specific antigen,TPSA)联合鉴别PCa与BPH的AUC值分别为0.843、0.830、0.896及0.927。DeLong检验显示ADC值与ADC-T2联合,ADC值、T2值、ADC-T2模型与ADC-T2-年龄-TPSA联合模型的ROC差异存在统计学意义(P<0.05)。ADC值与T2值呈正相关(r=0.331,P<0.01)。结论DWI及T2 mapping序列在鉴别PCa与BPH方面具有较好的价值,并且两序列联合临床指标时诊断效能提升,可为临床无创诊断PCa及BPH提供很好的指导意义。 展开更多
关键词 前列腺癌 前列腺增生 扩散加权成像 T2 mapping成像 磁共振成像 鉴别诊断
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Moho depth inversion in the Tibetan Plateau from high-precision gravity data 被引量:4
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作者 HuiYou He Jian Fang +3 位作者 HePing Sun DongMei Guo ZhiXin Xue Jing Hou 《Earth and Planetary Physics》 CAS CSCD 2023年第4期487-498,共12页
The Tibetan Plateau(TP)is the youngest orogenic belt resulting from a continental collision on the Earth.It is a natural laboratory for studying continental dynamics,such as continental convergence,plate subduction,an... The Tibetan Plateau(TP)is the youngest orogenic belt resulting from a continental collision on the Earth.It is a natural laboratory for studying continental dynamics,such as continental convergence,plate subduction,and plateau uplift.Investigating the deep structure of the TP has always been a popular issue in geological research.The Moho is the boundary between the crust and the mantle and therefore plays a crucial role in the Earth’s structure.Parameters such as depth and lateral variation,as well as the fine structure of the crust-mantle interface,reveal the lithospheric dynamics in the TP.Two methods are generally employed to study the Moho surface:seismic detection and gravity inversion.Seismic detection has the characteristic of high precision,but it is limited to a few cross-sectional lines and is quite costly.It is not suitable for and cannot be carried out over a large area of the TP.The Moho depth over a large area can be obtained through gravity inversion,but this method is affected by the nature of gravity data,and the accuracy of the inversion method is lower than that of seismic detection.In this work,a high-precision gravity field model was selected.The Parker-Oldenburg interface inversion method was used,within the constraints of seismic observations,and the Bott iteration method was introduced to enhance the inversion efficiency.The Moho depth in the TP was obtained with high precision,consistent with the seismic detection results.The research results showed that the shape of the Moho in the TP is complex and the variation range is large,reaching 60−80 km.In contrast with the adjacent area,a clear zone of sharp variation appears at the edge of the plateau.In the interior of the TP,the buried depth of the Moho is characterized by two depressions and two uplifts.To the south of the Yarlung Zangbo River,the Moho inclines to the north,and to the north,the Moho depresses downward,which was interpreted as the Indian plate subducting to the north below Tibet.The Moho depression on the north side of the Qiangtang block,reaching 72 km deep,may be a result of the southward subduction of the lithosphere.The Moho uplift of the Qiangtang block has the same strike as the Bangong−Nujiang suture zone,which may indicate that the area is compensated by a low-density and low-velocity mantle. 展开更多
关键词 GRAVITY MOHO Tibetan Plateau SGG-UGM-2(2159-order high-precision gravity field model)
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High-precision nonisothermal transient wellbore drift flow model suitable for the full flow pattern domain and full dip range 被引量:2
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作者 Wen-Qiang Lou Da-Lin Sun +5 位作者 Xiao-Hui Sun Peng-Fei Li Ya-Xin Liu Li-Chen Guan Bao-Jiang Sun Zhi-Yuan Wang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第1期424-446,共23页
A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multi... A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multiphase flow database with 3561 groups of data and developed a drift closure relationship with stable continuity and high adaptability.Second,a high-order numerical scheme with strong fault capture ability is constructed by effectively combining MUSCL technology,van Albada slope limiter and AUSMV numerical scheme.Finally,the energy equation is coupled into the AUSMV numerical scheme of the drift flow model in the form of finite difference.A transient non-isothermal wellbore multiphase flow model with wide applicability is formed by integrating the three technologies,and the effects of various factors on the calculation accuracy are studied.The accuracy of the simulator is verified by comparing the measurement results with the blowout experiment of a full-scale experimental well. 展开更多
关键词 Drift closure relation Non-isothermal model high-precision Multiphase flow solver Wellbore pressure control
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T_(1)-mapping鉴别腮腺常见肿瘤的初探
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作者 文宝红 张赞霞 +3 位作者 朱靖 付坤 张勇 程敬亮 《放射学实践》 CSCD 北大核心 2024年第2期189-194,共6页
目的:探讨T_(1)-mapping和分段读出DWI(RESOLVE-DWI)在腮腺常见肿瘤鉴别诊断中的价值。方法:回顾性分析2018年6月-2022年8月经病理证实的169例腮腺常见肿瘤患者的T_(1)-mapping及分段读出DWI资料。其中,多形性腺瘤85例,Warthin瘤32例,... 目的:探讨T_(1)-mapping和分段读出DWI(RESOLVE-DWI)在腮腺常见肿瘤鉴别诊断中的价值。方法:回顾性分析2018年6月-2022年8月经病理证实的169例腮腺常见肿瘤患者的T_(1)-mapping及分段读出DWI资料。其中,多形性腺瘤85例,Warthin瘤32例,恶性肿瘤52例。测量并比较三组肿瘤的T_(1)及ADC值,运用受试者工作特征(ROC)曲线评价T_(1)、ADC及二者联合(T_(1)+ADC)对腮腺肿瘤的鉴别诊断价值。采用Delong检验比较各参数的AUC的差异。结果:三组肿瘤的T_(1)值和ADC值的差异均有统计学意义(P<0.001);组间两两比较,差异均有统计学意义(P<0.001);多形性腺瘤的T_(1)值及ADC值最高;恶性肿瘤次之,Warthin瘤最低。T_(1)和ADC鉴别多形性腺瘤与Warthin瘤、多形性腺瘤与恶性肿瘤、Warthin瘤与恶性肿瘤的AUC分别为0.914和0.997、0.664和0.869、0.835和0.695,Delong检验显示2个参数AUC的差异均无统计学意义(P>0.05)。T_(1)+ADC鉴别多形性腺瘤与Warthin瘤、多形性腺瘤与恶性肿瘤的AUC均显著高于T_(1)(1.000 vs.0.914、0.873 vs.0.664,P均<0.001);T_(1)+ADC鉴别Warthin瘤与恶性肿瘤的AUC显著高于T_(1)(0.895 vs.0.835,P<0.001)和ADC(0.895 vs.0.695,P<0.001)。结论:T_(1)-mapping和RESOLVE-DWI有助于鉴别诊断腮腺常见肿瘤,二者联合诊断可提高鉴别诊断效能。 展开更多
关键词 腮腺肿瘤 磁共振成像 T_(1)-mapping 弥散加权成像
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Research on the principle of space high-precision temperature control system of liquid crystals based Stokes polarimeter 被引量:1
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作者 Xin-Wei Zhang Yang Zhang +2 位作者 Jia-Ben Lin Jun-Feng Hou Yuan-Yong Deng 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第1期97-104,共8页
The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and wi... The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and will be applied for magnetic field measurement in the first space-based solar observatory satellite developed by China,Advanced Space-based Solar Observatory.However,the liquid crystals based Stokes polarimeter in space is not a mature technology.Therefore,it is of great scientific significance to study the control method and characteristics of the device.The retardation produced by a liquid crystal variable retarder is sensitive to the temperature,and the retardation changes 0.09°per 0.10℃.The error in polarization measurement caused by this change is 0.016,which affects the accuracy of magnetic field measurement.In order to ensure the stability of its performance,this paper proposes a high-precision temperature control system for liquid crystals based Stokes polarimeter in space.In order to optimize the structure design and temperature control system,the temperature field of liquid crystals based Stokes polarimeter is analyzed by the finite element method,and the influence of light on the temperature field of the liquid crystal variable retarder is analyzed theoretically.By analyzing the principle of highprecision temperature measurement in space,a high-precision temperature measurement circuit based on integrated operational amplifier,programmable amplifier and 12 bit A/D is designed,and a high-precision space temperature control system is developed by applying the integral separation PI temperature control algorithm and PWM driving heating films.The experimental results show that the effect of temperature control is accurate and stable,whenever the liquid crystals based Stokes polarimeter is either in the air or vacuum.The temperature stability is within±0.0150℃,which demonstrates greatly improved stability for the liquid crystals based Stokes polarimeter. 展开更多
关键词 liquid crystals based Stokes polarimeter high-precision temperature measurement space high-precision temperature control temperature field analysis PID control
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A Design of High-precision High-Voltage Fiber-Optic Analog Signal Isolation Converter 被引量:1
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作者 李建伟 许留伟 +1 位作者 刘小宁 杨雷 《Plasma Science and Technology》 SCIE EI CAS CSCD 2002年第3期1281-1287,共7页
This paper introduces a design of high-precision high-voltage fiber-optic analog sig-nal isolation converter based on the technology of Voltage-to-Frequency (V/F) and Frequency-to-Voltage (F/V) conversion. It describe... This paper introduces a design of high-precision high-voltage fiber-optic analog sig-nal isolation converter based on the technology of Voltage-to-Frequency (V/F) and Frequency-to-Voltage (F/V) conversion. It describes the principle, system configuration and hardware design. 展开更多
关键词 In DESIGN A Design of high-precision High-Voltage Fiber-Optic Analog Signal Isolation Converter FVC VFC
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Isomap对人脸图像的降维处理
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作者 刘瑞银 张汇洋 《沈阳师范大学学报(自然科学版)》 CAS 2024年第4期346-349,共4页
人脸图像数据常常由几千或几万个像素点组成,每个像素点都代表一个特征。在进行人脸识别、图像分类等任务时,若使用全部像素点,会导致特征维度非常高,进而造成分析处理数据效率低下、储存成本过高等问题,此时对数据进行降维就极为重要... 人脸图像数据常常由几千或几万个像素点组成,每个像素点都代表一个特征。在进行人脸识别、图像分类等任务时,若使用全部像素点,会导致特征维度非常高,进而造成分析处理数据效率低下、储存成本过高等问题,此时对数据进行降维就极为重要。等距特征映射(isometric feature mapping,Isomap)是流形学习中一个非线性降维方法。对于人脸这样的高维流形结构,Isomap可以找到最优的低维表示,并保持原始数据之间的拓扑关系,从而更好地捕捉数据的局部结构和流形特征,例如人脸的表情、姿态、光照等因素。利用Isomap方法对jaffe人脸数据集中的部分人脸灰度图像进行降维处理,对高维数据进行可视化,得到该组数据的各个表情的位置分布,以此来展示Isomap对人脸图像数据的降维效果。 展开更多
关键词 人脸图像 降维 等距特征映射 可视化
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2型糖尿病老年病人心肌纤维化T1-Mapping与左心室应变参数的相关性分析
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作者 王玲 鲁国卫 +3 位作者 章宏 尹成俊 陈凤 田荣华 《安徽医药》 CAS 2024年第9期1866-1870,共5页
目的探究2型糖尿病(T2DM)老年病人心肌纤维化T1-Mapping参数与左心室应变参数之间的相关性。方法以2019年8月至2022年8月在孝感市中心医院就诊的T2DM病人82例为研究对象,根据病人的病程分为短期T2DM组40例(病程<5年)和长期T2DM组42例... 目的探究2型糖尿病(T2DM)老年病人心肌纤维化T1-Mapping参数与左心室应变参数之间的相关性。方法以2019年8月至2022年8月在孝感市中心医院就诊的T2DM病人82例为研究对象,根据病人的病程分为短期T2DM组40例(病程<5年)和长期T2DM组42例(病程≥5年),以同期招募的健康志愿者40例为对照组。比较各组间左心室应变参数及T1-Mapping参数。采用多元线性逐步回归法分析T1-Mapping参数的影响因素。采用相关性分析T1-Mapping参数与左心室应变参数的相关性。结果短期T2DM组病人左室周向峰值舒张应变率(PDSR)[1.25(0.95,1.50)1/s比1.40(1.20,1.70)1/s]较对照组降低(P<0.05),细胞外体积(ECV)[31.00(29.00,33.50)%比29.00(27.00,32.00)%]较对照组升高(P<0.05)。与对照组比较,长期T2DM组病人左室纵向峰值应变(PS)[−14.50(−12.38,−16.50)%比−16.15(−14.60,−18.30)%]、径向PDSR[(−2.58±0.83)1/s比(−3.32±0.88)1/s]、周向PDSR[0.90(0.70,1.20)1/s比1.40(1.20,1.70)1/s]、纵向PDSR[0.70(0.58,0.90)1/s比1.10(0.80,1.38)1/s]降低(P<0.05),ECV[34.00(32.00,35.00)%比29.00(27.00,32.00)%]升高(P<0.05)。与短期T2DM组比较,长期T2DM组病人左室纵向PS[−14.50(−12.38,−16.50)%比−16.15(−14.45,−18.38)%]、径向PDSR[(−2.58±0.83)1/s比(−3.61±0.76)1/s]、周向PDSR[0.90(0.70,1.20)1/s比1.25(0.95,1.50)1/s]、纵向PDSR[0.70(0.58,0.90)1/s比1.10(0.80,1.30)1/s]降低(P<0.05),ECV[34.00(32.00,35.00)%比31.00(29.00,33.50)%]升高(P<0.05)。多元线性回归分析结果示,糖尿病病程是T2DM病人ECV的独立影响因素(β=0.29,P<0.05)。Spearman相关性分析结果示,T2DM病人ECV与左室纵向PS(r_(s)=0.35,P<0.05)、纵向峰值收缩应变率(PSSR)(r_(s)=0.31,P<0.05)呈显著正相关,与左室周向PDSR(r_(s)=−0.29,P<0.05)、纵向PDSR(r_(s)=−0.43,P<0.05)呈显著负相关。结论心脏磁共振T1-Mapping可能发现T2DM病人早期心肌纤维化,T1-Mapping参数与左心室应变参数显著相关。 展开更多
关键词 糖尿病 2型 心脏磁共振 心肌纤维化 心肌应变 T1-mapping参数
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