检索结果-南通市图书馆

A review of real-time multi-GNSS precise orbit determination based on the filter method

在线全文

学校读者我要写书评

暂无评论

Satellite Navigation 2022年第3期3卷 1-15,I0002页

作者： Yidong Lou Xiaolei Dai xiaopeng Gong Chenglong Li Yun Qing Yang Liu Yaquan peng Shengfeng Gu GNSS Research Center Wuhan University129 Luoyu RoadWuhanHubeiChina Key Laboratory of Earthquake Geodesy Institute of SeismologyChina Earthquake AdministrationWuhan430071China First Institute of Oceanography Ministry of Natural ResourcesQingdao266061China

Stable and reliable high-precision satellite orbit products are the prerequisites for the positioning services with high *** general,the positioning accuracy depends strongly on the quality of satellite orbit and clock products,especially for absolute positioning modes,such as Precise Point Positioning(PPP).With the development of real-time services,real-time Precise Orbit Determination(POD)is indispensable and mainly includes two methods:the ultra-rapid orbit prediction and the real-time filtering orbit *** real-time filtering method has a great potential to obtain more stable and reliable products than the ultra-rapid orbit prediction method and thus has attracted increasing attention in commercial companies and research ***,several key issues should be resolved,including the refinement of satellite dynamic stochastic models,adaptive filtering for irregular satellite motions,rapid convergence,and real-time Ambiguity Resolution(AR).This paper reviews and summarizes the current research progress in real-time filtering POD with a focus on the aforementioned *** addition,the real-time filtering orbit determination software developed by our group is introduced,and some of the latest results are *** Three-Dimensional(3D)real-time orbit accuracy of GPS and Galileo satellites is better than 5 cm with *** terms of the convergence time and accuracy of kinematic PPP AR,the better performance of the filter orbit products is validated compared to the ultra-rapid orbit products.

关键词： Multi-GNSS Real-time precise orbit determination Square root information filter Ambiguity resolution

Effects of Land Use Change on Ecosystem Services in Arid Area Ecological Migration

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Geographical Science 2018年第5期28卷 894-906页

作者： LIU xiaopeng CHEN Xiao HUA Kaiping WANG Yajuan WANG peng HAN Xiaojia YE Junyan WEN Shengqiang School of Resources and Environment Ningxia University Yinchuan 750021 China Key Laboratory (China-Arab) of Resource Evaluation and Environmental Regulation of Arid Region in Ningxia Yinchuan 750021 China School of Tourism and Environment Shaanxi Normal University Xi'an 710062 China

Ecological migration is the process of increasing the population density in the immigration area and transferring the ecological pressure from emigration area to immigration area. This process may result in significant changes in land use and land cover in the area of immigration and have an important effect on ecosystem services. Therefore, scientifically revealing the effects and differentiation mechanisms of ecological migration on ecosystem services is becoming an important issue related to the implementation of the national ecological migration strategy in China. This study employed the Hongsibu District as a typical example of ecological migration. Hongsibu District is located in the central Ningxia steppe and desert steppe areas. Remote sensing data covering five periods from the period before ecological migration in 1995 and after migration in 2000, 2005, 2010, and 2015 was used to measure the value of ecosystem services(ESV). A geographical detector model and the value of ecosystem services model were used to diagnose the dynamic mechanism of the effects of land use change on ecosystem services. The results showed that: 1) The development of large-scale ecological resettlement has caused the area of cultivated land and urbanized land area to increase significantly in the area of immigration, while the grass area decreased significantly. 2) The overall value of the Hongsibu ecosystem services increased in a form of a ‘V'. Among them, during the period of 1995–2005, the overall ESV decreased and had an annual rate of change of-0.67%. During the period of development 2005–2015, the ESV increased steadily, with an annual rate of change of 0.79%. 3) The proportion and total ESV in soil formation and protection, waste treatment, and biodiversity conservation of the Hongsibu District decreased from 57.61% in 1995 to 56.17% in 2015, indicating that the region's ecological regulation function slightly decreased. 4) The ESV in the Hongsibu District, showed a low dist

关键词： ecological migration land use change ecosystem services geo-detector arid area Hongsibu district

基于某特殊铁路标准的电力机车耐撞性设计方法

在线全文

学校读者我要写书评

暂无评论

铁道车辆 2024年第3期62卷 117-123页

作者：冯国江齐红瑞范晓鹏朱涛谷鹏肖守讷中车大同电力机车有限公司山西大同037038 西南交通大学轨道交通运载系统全国重点实验室四川成都610031

为了保证电力机车被动安全的普遍适用性,基于某特殊铁路标准,以某型电力机车车体为研究对象,开展了电力机车耐撞性设计方法研究。首先,在分析研究相关机车耐撞性标准的基础上,确定了符合特殊标准的碰撞工况;然后,开展了基于碰撞能量管... 详细信息

为了保证电力机车被动安全的普遍适用性,基于某特殊铁路标准,以某型电力机车车体为研究对象,开展了电力机车耐撞性设计方法研究。首先,在分析研究相关机车耐撞性标准的基础上,确定了符合特殊标准的碰撞工况;然后,开展了基于碰撞能量管理的电力机车车钩缓冲装置能量配置研究;最后,在建立电力机车碰撞动力学与有限元模型的基础上,对比分析了典型工况下基于碰撞能量管理设计前后机车的耐撞性指标。结果表明:碰撞后的车体自身平均加速度、车厢纵向永久变形量和门窗对角永久变形量等各项耐碰撞性能指标均能满足相关要求,验证了机车碰撞能量管理设计的合理性与有效性,提升了该型机车的耐撞性能。

关键词：电力机车碰撞能量管理车钩缓冲装置耐撞性特殊铁路标准

同方期刊数据库

在线全文

学校读者我要写书评

暂无评论

我国药食同源物质副产品应用现状与对策

中国果菜 2024年第5期44卷 20-26页

作者：梁彦霄于佳琦王晓鹏于文瑶吴澎山东农业大学食品科学与工程学院山东泰安271018 山东第一医科大学综和实验室山东泰安271018 泰安市徂徕山林场山东泰安271000

随着“健康中国”战略的提出和食品科技的快速发展,我国对药食同源物质的开发力度不断加大,加工过程中产生大量的副产品得不到充分利用。本文以酸枣仁、葛根、石榴、花椒和黄精五种药食同源物质为例综述了其副产品综合利用的研究现状,... 详细信息

随着“健康中国”战略的提出和食品科技的快速发展,我国对药食同源物质的开发力度不断加大,加工过程中产生大量的副产品得不到充分利用。本文以酸枣仁、葛根、石榴、花椒和黄精五种药食同源物质为例综述了其副产品综合利用的研究现状,总结了存在的问题,并对药食同源物质副产品的应用提出展望,以期提高其综合利用效率和减少对环境的污染。

关键词：药食同源副产品综合利用发展策略

维普期刊数据库博看期刊

连作对植烟土壤微生物群落与环境因子的影响及相关性分析

在线全文

学校读者我要写书评

暂无评论

山东农业科学 2024年第1期56卷 113-118页

作者：朱德伦贾孟朱宣全徐照丽王戈王娜邓小鹏杜宇周鹏白羽祥云南农业大学烟草学院云南昆明650500 云南省烟草农业科学研究院烟草农学研究中心云南昆明650021

为探究连作对植烟土壤微生物群落和土壤环境因子的影响及其相互作用,对连作和轮作植烟土壤进行16S rRNA高通量测序,并对土壤理化性质、酶活性、酚酸类物质等环境因子进行测定。结果表明,连作植烟土壤中鞘氨醇单胞菌属(Sphingomonas)、... 详细信息

为探究连作对植烟土壤微生物群落和土壤环境因子的影响及其相互作用,对连作和轮作植烟土壤进行16S rRNA高通量测序,并对土壤理化性质、酶活性、酚酸类物质等环境因子进行测定。结果表明,连作植烟土壤中鞘氨醇单胞菌属(Sphingomonas)、水恒杆菌属(Mizugakiibacter)、橙色出芽单胞菌属(Gemmatimonas)、人参土黄菌属(Flavisolibacter)相对丰度增加,细菌生态网络复杂度降低;速效钾、有效磷含量增加,水解性氮、硝态氮含量降低,转化酶活性降低,酚酸物质积累。Pearson相关性分析表明,土壤速效钾、有效磷、水解性氮、硝态氮和转化酶以及酚酸等环境因子与鞘氨醇单胞菌属、水恒杆菌属、橙色出芽单胞菌属、人参土黄菌属呈显著相关。可见,连作导致植烟土壤养分失衡,影响土壤微生物群落结构,此结论可为烤烟连作障碍研究提供理论依据。

关键词：植烟土壤连作微生物环境因子相关性分析

中药多途径治疗急性胰腺炎并发腹间隔室综合征疗效评价:一项荟萃分析

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

安徽医药 2022年第12期26卷 2333-2340页

作者：秦百君陈月桥彭晓鹏刘琨荣杨昕赵权卜献忠黄子彦陈国忠广西中医药大学研究生院广西南宁530001 广西中医药大学第一附属医院脾胃科广西南宁530023 新乡医学院第三附属医院脾胃科河南新乡453000 防城港市中医医院脾胃科广西防城港538021

目的系统评价中药多途径治疗急性胰腺炎并发腹间隔室综合征疗效。方法检索中国知网、万方、维普、Sinomed、PubMed、Embase、CochraneLibrary自建库至2020年12月1日收录的中医药治疗急性胰腺炎并发腹间隔室综合征的临床试验,RevMan5.3... 详细信息

目的系统评价中药多途径治疗急性胰腺炎并发腹间隔室综合征疗效。方法检索中国知网、万方、维普、Sinomed、PubMed、Embase、CochraneLibrary自建库至2020年12月1日收录的中医药治疗急性胰腺炎并发腹间隔室综合征的临床试验,RevMan5.3软件进行荟萃分析。结果共纳入17项研究,共1033例病人;荟萃分析显示,与西药基础治疗比较,中西药联用可显著降低腹内压[标准化均数差(SMD)95%CI:−0.63(−0.83,0.43)];与西药基础治疗比较,联用中药组可显著降低急性生理学和慢性健康状况评价Ⅱ(APACHEⅡ)评分[SMD 95%CI:−0.65(−0.87,0.43)];与西药基础治疗比较,联用中药组可有效缩短排便恢复时间[SMD 95%CI:−0.68(−1.14,0.22)];此外,小样本的研究表明中西医结合相较于单纯西药治疗可降低病人死亡情况[比值比(OR)95%CI:1.04(−1.91,−0.16)]。结论中药治疗急性胰腺炎并发腹间隔室综合征可降低腹内压、减少临床APACHEⅡ评分、缩短病人排便恢复时间。

关键词：胰腺炎腹间隔室综合征中草药综述荟萃分析

A Local Reference Frame Construction Method Based on the Signed Surface Variation

在线全文

学校读者我要写书评

暂无评论

Journal of Geodesy and Geoinformation Science 2021年第3期4卷 25-37页

作者： xiaopeng YAN Wei ZHOU Rencan peng Wenliang PAN Lei WANG Guoxin HU The P.L.A.91550 Unit Dalian 116023China Department of Military Oceanography and Hydrography&Cartography Dalian Naval AcademyDalian 116018China

A fast local reference frame(LRF)construction method based on the signed surface variation is proposed,which can adapt to the real-time applications such as self-driving,face recognition,object *** z-axis of the LRF is generated based on the concavity of the local surface of *** x-axis is constructed by the weighted vector sum of a set of projection vectors of the local neighborhoods around *** performance of the proposed LRF is evaluated on six standard datasets and compared with six state-of-the-art LRF construction methods(e.g.,BOARD,FLARE,SHOT,RoPS and TOLDI).Experimental results validate the high repeatability,robustness,universality and time efficiency of our method.

关键词： signed surface variation local reference frame point cloud feature extraction

Intervertebral disc generation tissue engineering treatment platform: gelatin-methacryloyl hydrogel composite system

在线全文

学校读者我要写书评

暂无评论

中华医学杂志（英文版） 2023年第19期136卷 2383-2385页

作者： Yicun Hu xiaopeng Wang Meiling Zhao peng Wang Xiaobo Zhang Haiyu Zhou Jintao Shi Mengxue Cong China 730000 China 730000 China 710000 China 646000 China 133000

To the Editor: In middle-aged and elderly individuals, intervertebral disc (IVD) degeneration (IVDD) can often cause low back pain (LBP). IVDD has a complex mechanism with many influencing factors. Biological changes in degenerative IVDs mainly include structural abnormalities of the nucleus pulposus (NP), annulus fibrosus (AF), and cartilage endplate, as well as changes in the composition and amount of extracellular matrix (ECM). IVDD disease is treated conservatively, followed by surgery, but these are symptomatic treatments, with high complication rates. Gelatin-methacryloyl (GelMA) hydrogel system therapy reduces complications while treating the cause. Through minimally invasive surgery, GelMA hydrogels are used to deliver regenerative cells and/or biological factors to the target area to eliminate symptoms and promote IVD cell regeneration. Or, using three-dimensional (3D) printing technology, a bionic IVD can be constructed to replace a severely degenerated IVD. This is a research hotspot in the field of regenerative medicine and tissue engineering.

关键词：

基于影像组学构建识别临床高风险颈动脉斑块的机器学习模型

在线全文

学校读者我要写书评

暂无评论

中国胸心血管外科临床杂志 2024年第1期31卷 24-34页

作者：王晓晖吕晓烁刘展甄雅南林凡郑夏刘晓鹏孙光温见燕叶志东刘鹏北京大学中日友好临床医学院北京100029 中日友好医院心脏血管外科北京100029

目的构建识别临床高风险颈动脉斑块的影像组学模型。方法回顾性分析2016年12月—2022年6月中日友好医院颈动脉狭窄患者的临床资料。依据6个月内是否出现卒中、短暂性脑缺血发作及其他脑血管临床症状将患者分为临床高风险斑块组和临床低... 详细信息

目的构建识别临床高风险颈动脉斑块的影像组学模型。方法回顾性分析2016年12月—2022年6月中日友好医院颈动脉狭窄患者的临床资料。依据6个月内是否出现卒中、短暂性脑缺血发作及其他脑血管临床症状将患者分为临床高风险斑块组和临床低风险斑块组,纳入关键变量建立极致梯度提升、支持向量机、高斯朴素贝叶斯、逻辑回归、K最邻近以及人工神经网络6种机器学习模型,随后结合logistic回归分析临床危险因素构建联合预测模型。结果最终纳入患者652例,其中男427例、女225例,平均年龄68.2岁。分析结果显示在6种影像组学机器学习模型中,极致梯度提升模型的表现最好,验证集曲线下面积(area under the curve,AUC)为0.751,同时利用临床资料以及颈动脉影像资料建立的极致梯度提升联合预测模型验证集AUC为0.823。结论影像组学特征联合临床特征构建模型可以有效预识别临床高风险颈动脉斑块。

关键词：颈动脉斑块影像组学机器学习

同方期刊数据库