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Predominant types of regional cold waves in North China and their historical changes

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Atmospheric and Oceanic Science Letters 2024年第4期17卷 46-51页

作者： Xinyi Cheng Yiyi Zhang jiandong li Xin Hao Center for Climate System Prediction Research/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of EducationNanjing University of Information Science&TechnologyNanjingChina Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjingChina

寒潮事件对东亚地区的社会经济,生态系统和人体健康影响巨大.根据1980-2019年间10月至次年3月的每日寒潮记录和K-means聚类,本文识别出了中国两种不同类型的区域性寒潮(T1和T2). T1区域性寒潮主要影响东北地区,T2区域性寒潮则主要影响... 详细信息

寒潮事件对东亚地区的社会经济,生态系统和人体健康影响巨大.根据1980-2019年间10月至次年3月的每日寒潮记录和K-means聚类,本文识别出了中国两种不同类型的区域性寒潮(T1和T2). T1区域性寒潮主要影响东北地区,T2区域性寒潮则主要影响华北和东部地区.与T1区域性寒潮相比, T2区域性寒潮强度更强,持续时间更长,影响范围更广. 1980–2019年期间, T1区域性寒潮的频率显著增加,而T2区域性寒潮的频率则没有趋势变化. T1和T2区域性寒潮事件均与西伯利亚高压增强有关,然而与它们相关的对流层中层波列明显不同.在T1区域性寒潮事件发生期间,西伯利亚-蒙古上空出现负-正模态的500-hPa位势高度异常波列,削弱了东亚大槽,导致西伯利亚冷空气东移.T1区域寒潮频次增加趋势可能与全球变暖引起的500-hPa位势高度的线性趋势变化有关.与T2区域寒潮事件相关的波列则在乌拉尔山脉,蒙古和华北地区形成了脊-槽-脊环流异常,导致冷空气向东南方向入侵.本文得出结论,由于两类区域寒潮影响不同,西伯利亚高压增强和对流层中层波列模态在我国区域性寒潮事件的预报中应综合考虑.

关键词：寒潮 K-means聚类西伯利亚高压波列

Reduced Spring Precipitation Bias and Associated Physical Causes over South China in FGOALS-f3 Climate Models:Experiments with the Horizontal Resolutions

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Journal of Meteorological Research 2024年第4期38卷 784-804页

作者： Peng ZI Yimin liU jiandong li Ruowen YANG Bian HE Qing BAO Department of Atmospheric Science Yunnan UniversityKunming 650504 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029

Considerable spring precipitation occurs over South China(SC),a region that is adjacent to large-scale Asian topography and *** reasonable simulation is crucial for improving regional climate *** study investigates spring precipitation biases over SC and their possible causes in atmosphere-only and coupled Flexible Global Ocean–Atmosphere–Land System finite-volume version 3(FGOALS-f3) models with different horizontal *** performance of spring precipitation simulation over SC varies across different FGOALS-f3 model versions,with the best reproducibility in the high-resolution coupled model(25 km).In the low-resolution atmosphere-only model(100–125 km),the precipitation dry bias over SC is closely linked to overestimated surface sensible forcing over the eastern Tibetan Plateau(TP),which weakens the subtropical anticyclone over the western Pacific(SAWP) through regional circulation *** contrast,the high-resolution atmosphere-only model further amplifies surface thermal forcing in the Asian continents,causing intensified land–sea thermal contrast between the Southeast Asian continents and western Pacific,enhanced southerly winds and SAWP,and increased water vapor transport into ***,the reduced middle–high level cold bias over 10°–30°N in the high-resolution atmosphere-only model intensifies the East Asian westerly jet and ascent over SC,leading to enhanced spring precipitation *** high-resolution coupled model simulation not only reduces sea surface cold bias over the Bay of Bengal,thus intensifying the Indian–Burma trough and strengthening low-level water vapor transport into SC,but also enhances ascent over *** a result,the high-resolution coupled model better reproduces the magnitude and pattern of spring precipitation over SC than its atmosphere-only *** with low-resolution models,the domain-mean spring precipitation dry bias decreases by 11.2% over SC in the high-resolution atmosphere-only mod

关键词： South China spring precipitation high resolution Flexible Global Ocean–Atmosphere–Land System finite-volume version 3(FGOALS-f3)models simulation

Epidemiological Characteristics of Dengue Fever-China,2005–2023

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China CDC weekly 2024年第41期6卷 1045-1048页

作者： Zhuowei li Xiaoxia Huang Aqian li Shanshan Du Guangxue He jiandong li National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases NHC Key Laboratory of BiosafetyNHC Key Laboratory of Medical Virology and Viral DiseasesNational Institute for Viral Disease Control and PreventionChinese Center for Diseases Control and PreventionBeijingChina

Introduction:The global incidence of dengue fever has increased significantly over the past two decades,and China faces a significant upward trend in dengue control ***:Data were obtained from China’s NNDRS from 2005 to *** regression software was used to analyze temporal trends,while SaTScan software was used to analyze spatial,seasonal,and spatiotemporal *** software was used to visualize ***:A total of 117,892 dengue cases were reported from 2005 to 2023,with significant fluctuation in annual reported *** was not endemic in *** outbreaks most likely occurred in the southwestern,southeastern coastal,and inland areas of *** outbreaks have occurred between June and November,generally peaking in September or October,around epidemiological week(EW)***:Dengue challenges in China are *** case monitoring,proactive control interventions,and staff mobilization should be implemented before June to ensure a timely response to autochthonous outbreaks.

关键词： inland likely southwestern

Two Peaks of Seasonal Influenza Epidemics -China, 2023

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China CDC weekly 2024年第36期6卷 905-910页

作者： Yiran Xie Shuxia lin Xiaoxu Zeng Jing Tang Yanhui Cheng Weijuan Huang jiandong li Dayan Wang National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease National Institute for Viral Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina.

Introduction:Influenza is a communicable respiratory disease that causes annual epidemics and occasional unpredictable *** study examines the occurrence of two unexpected influenza peaks within the year ***:Influenza-like illness(Ili)data were reported,and specimens of Ili were collected by designated surveillance *** cases were confirmed using real-time reverse transcription polymerase chain reaction(rRT-PCR)testing conducted at national surveillance network *** data were then submitted to the Chinese Influenza Surveillance Information ***:From December 2022 to January 2023,influenza activity was minimal until a spring epidemic began in February,peaking in late *** outbreak spread from the north to the south,with A(H1N1)pdm09 being the predominant strain and A(H3N2)also circulating *** positivity rate in northern and southern provincial-level administrative divisions(PLADs)reached 60.0%(week 10)and 60.2%(week 13),respectively,before dropping to below 5%from May to ***,rates surged starting in week 41 in the south and week 44 in the north,peaking at 54.4%(week 50)and 44.0%(week 49),respectively,and remained high until the end of 2023.A(H3N2)became the prevailing strain,with a notable increase in B/Victoria lineage viruses from December,resulting in two peaks during the 2023 influenza ***:The pattern of the influenza epidemic shifted due to the coronavirus disease 2019(COVID-19)outbreak and is gradually returning to its usual seasonal and intensity *** is,therefore,crucial to continuously strengthen influenza surveillance,enhance the influenza surveillance network,and lay the groundwork for advancing integrated surveillance of multiple pathogens in China.

关键词： prevailing surveillance Influenza

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空空高速移动通信信号的频偏估计和跟踪算法

西安电子科技大学学报 2024年第3期51卷 30-37页

作者：张欣李建东西安电子科技大学空天地一体化综合业务网全国重点实验室陕西西安710071

空空高速移动场景下飞行平台通信信号的多普勒频率范围大且变化快。针对现有频偏估计和跟踪算法难以兼顾估计精度和工程可实现性的难题,提出了低复杂度的新型高精度频偏估计和跟踪算法。首先根据空空高速移动场景下多普勒频率快速变化... 详细信息

空空高速移动场景下飞行平台通信信号的多普勒频率范围大且变化快。针对现有频偏估计和跟踪算法难以兼顾估计精度和工程可实现性的难题,提出了低复杂度的新型高精度频偏估计和跟踪算法。首先根据空空高速移动场景下多普勒频率快速变化且具有时空相关性特征,在传统频偏模型的基础上构建适用于空空高速移动场景的时变频偏模型;然后基于此模型将相邻短前导的频偏估计值进行相互关联并处理,将频偏精度优化问题转化为经典的超定线性方程组的优化求解问题,最大限度地抑制了估计噪声,提高了频偏估计精度。仿真结果表明,该算法估计的残余频偏相对于经典算法大幅降低,当信噪比大于5 dB时,残余频偏的均方根误差控制在100 Hz范围内。针对该算法求解过程中存在的数值稳定性问题,给出了相应的工程可实现方法。该算法采用前馈补偿频偏跟踪方法,与传统的锁相环反馈跟踪方法相比,提高了系统的稳定性和时效性。

关键词：高速移动通信频偏模型频偏估计频偏跟踪

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融合双向注意力和对比增强机制的多标签文本分类

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计算机工程与应用 2024年第16期60卷 105-115页

作者：李建东傅佳李佳琦辽宁工程技术大学软件学院辽宁葫芦岛125105 辽宁工程技术大学矿业学院辽宁阜新123000

现有多标签文本分类模型面对文本序列增长时语义信息缺失,预测特定标签时忽略已有实例中的丰富知识等问题不能很好地解决,由此提出一种融合双向注意力和对比增强机制的多标签文本分类模型。结合BERT词嵌入,利用CTransformer模型分别获... 详细信息

现有多标签文本分类模型面对文本序列增长时语义信息缺失,预测特定标签时忽略已有实例中的丰富知识等问题不能很好地解决,由此提出一种融合双向注意力和对比增强机制的多标签文本分类模型。结合BERT词嵌入,利用CTransformer模型分别获取序列的全局依赖关系和局部结构信息;使用双向注意力和标签嵌入进一步生成最终文本表示和标签表示,将文本信息与标签信息进行交互,得到更为全面的综合语义信息;利用对比增强机制进行KNN实例检索,设计一个多标签对比学习目标,使模型意识到KNN分类过程,并提高推理过程中检索邻居实例的质量。分类器根据标签表示和文本表示进行文本分类。为了评估模型的性能,在三个公开英文数据集上进行测试,实验结果表明提出的模型在P@K和nDCG@K指标上均优于其他主流基线模型。

关键词：多标签文本分类注意力机制对比增强机制 CTransformer模型多标签对比学习

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Mg-Nd合金室温和深冷变形行为的研究

稀有金属材料与工程 2024年第7期53卷 1944-1952页

作者：陈豪彭丽丽李建冬张静重庆大学材料科学与工程学院重庆400044 国家镁合金材料工程技术研究中心重庆400044

采用准原位电子背散射衍射(EBSD)、滑移迹线法和晶内取向轴法(IGMA),研究了轧制退火态Mg-Nd合金板材在室温(RT)和-150℃深冷(CT)条件下沿轧制方向压缩过程中的变形行为。结果表明:变形温度不影响孪生模式,但会显著影响孪生形核率以及滑... 详细信息

采用准原位电子背散射衍射(EBSD)、滑移迹线法和晶内取向轴法(IGMA),研究了轧制退火态Mg-Nd合金板材在室温(RT)和-150℃深冷(CT)条件下沿轧制方向压缩过程中的变形行为。结果表明:变形温度不影响孪生模式,但会显著影响孪生形核率以及滑移模式。相比于RT压缩,经相同的压缩变形(4%),CT压缩显著增大了样品变形过程中的局部应力,导致孪晶形核率提高了约10%,孪晶界总长度提高了约8%,并促进了非基面滑移,其比例由RT压缩时的45.5%增加至CT压缩的65.9%,此外,低温抑制了压缩变形过程中的基面滑移,其比例由RT压缩的54.5%降低至CT的34.1%。

关键词：变形温度变形行为 EBSD 滑移迹线 IGMA

储煤场堆载对地基和煤棚桩基影响的离心模型试验研究

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岩土工程学报 2024年第S1期46卷 197-201页

作者：元光宗李建东交通运输部天津水运工程科学研究院港口水工建筑技术国家工程研究中心天津300456 天津大学建筑工程学院天津300000

某大型储煤场位于沿海地带,建设初期通过真空堆载联合预压煤场软土地基进行了预处理。储煤场煤棚基础采用预应力高强度混凝土管桩(PHC桩)进行加固处理,并在其前方设置水泥搅拌桩(CDM桩)作为保护桩。为了研究煤场长期大面积堆载对地基和... 详细信息

某大型储煤场位于沿海地带,建设初期通过真空堆载联合预压煤场软土地基进行了预处理。储煤场煤棚基础采用预应力高强度混凝土管桩(PHC桩)进行加固处理,并在其前方设置水泥搅拌桩(CDM桩)作为保护桩。为了研究煤场长期大面积堆载对地基和桩基煤棚产生的影响,开展土工离心机模型试验,模拟了煤场循环堆卸载和30 a长期堆载两种工况。实验结果对煤场地基的沉降进行了预测,通过对桩基础的受力分析,进一步对煤场进行安全性评估。

关键词：离心模型试验软土地基沉降弯矩

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奥罗普切热:一个潜在全球卫生安全威胁?

病毒学报 2024年第5期40卷 1105-1110页

作者：刘铁柱李建东传染病溯源预警与智能决策全国重点实验室国家卫生健康委员会医学病毒和病毒病重点实验室中国疾病预防控制中心病毒病预防控制所北京102206

奥罗普切热是一种经节肢动物叮咬传播的病毒性传染病,在中、南美洲持续传播,不断扩散,已成为当地重大公共卫生问题。感染者早期临床表现与登革热、寨卡病毒病、基孔肯雅热等虫媒传染病相似,难以鉴别,不利于早发现、早诊断,及时落实防治... 详细信息

奥罗普切热是一种经节肢动物叮咬传播的病毒性传染病,在中、南美洲持续传播,不断扩散,已成为当地重大公共卫生问题。感染者早期临床表现与登革热、寨卡病毒病、基孔肯雅热等虫媒传染病相似,难以鉴别,不利于早发现、早诊断,及时落实防治措施。该病毒传播媒介在全球分布广泛,应对其进一步播散威胁全球公共卫生安全的风险予以关注,及时评估,做好应对。为了提高对本病的认识和诊疗意识,本文对奥罗普切热病原学、流行特征、临床表现和实验室诊断方法进行了归纳分析。

关键词：奥罗普切热病原学流行特征诊断方法