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Tomographic particle image velocimetry measurement on three-dimensional swirling flow in dual-stage counter-rotating swirler

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Chinese Journal of Aeronautics 2024年第3期37卷 7-20页

作者： Yuyang ZHOU Ling DONG mingtao SHANG Jibao LI Akira RINOSHIKA Key Laboratory of Fluid Mechanics of Ministry of Education Beihang UniversityBeijing 100191China School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China AECC Commercial Aircraft Engine Co. Ltd.Shanghai 200241China Department of Mechanical Systems Engineering Yamagata UniversityYamagata 992-8510Japan

Three-Dimensional(3D)swirling flow structures,generated by a counter-rotating dualstage swirler in a confined chamber with a confinement ratio of 1.53,were experimentally investigated at Re=2.3×10^(5)using Tomographic Particle Image Velocimetry(Tomo-PIV)and planar Particle Image Velocimetry(PIV).Based on the analysis of the 3D time-averaged swirling flow structures and 3D Proper Orthogonal Decomposition(POD)of the Tomo-PIV data,typical coherent flow structures,including the Corner Recirculation Zone(CRZ),Central Recirculation Zone(CTRZ),and Lip Recirculation Zone(LRZ),were extracted.The counter-rotating dual-stage swirler with a Venturi flare generates the independence process of vortex breakdown from the main stage and pilot stage,leading to the formation of an LRZ and a smaller CTRZ near the nozzle outlet.The confinement squeezes the CRZ to the corner and causes a reverse rotation flow to limit the shape of the CTRZ.A large-scale flow structure caused by the main stage features an explosive breakup,flapping,and Precessing Vortex Core(PVC).The explosive breakup mode dominates the swirling flow structures owing to the expansion and construction of the main jet,whereas the flapping mode is related to the wake perturbation.Confinement limits the expansion of PVC and causes it to contract after the impacting area.

关键词： Coherent structures Dual-stage counter-rotating swirler cup Precessing vortex core Proper orthogonal decomposition Swirling flow Tomographic particle image velocimetry

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Identifying drivers of urban landuse changes in the Wenchuan earthquake- affected area by using night-time light data

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Journal of Mountain Science 2024年第4期21卷 1140-1159页

作者： HUANG Tao DING mingtao GENG Dongxian GAO Zemin ZHENG Hao School of Civil Engineering and Architecture Southwest University of Science and TechnologyMianyang 621010China Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu 611756China Analysis and Test Center of Sichuan Province Chengdu 610023China

To learn the process of urban land evolution before and after an earthquake is vital to formulate the urban reconstruction control policies and recovery measures in the earthquake-stricken areas.However,spatiotemporal evolution and its driving factors of urban land in earthquake-prone areas remains limited due to the scarcity of ground observation data.This research,leveraging night-time light remote sensing imagery and land cover data,conducted a comprehensive analysis of the long-term evolution characteristics of urban land in earthquake-prone areas.It introduced methodologies for assessing the socio-economic impact and the primary natural environmental factors driving urban land evolution in these regions.To validate the proposed methods,the 2008 Wenchuan earthquake-affected area in China was selected as a representative study area.The results indicated that the average Digital Number(DN)values in socio-economically impacted areas showed a trend of rising,falling,and then rising again after the earthquake.DN values in three types of damaged areas including Type Ⅱ,Type Ⅲ,and Type Ⅳ exceeded pre-earthquake levels.The analysis of determinative factors influencing urban land evolution revealed that slope and elevation were key elements in controlling urban land expansion before the earthquake,whereas factors such as slope,elevation,lithology,and faults had a stronger influence on urban land expansion after the earthquake.It can be seen that,in view of the differences in the natural conditions of regions for post-disaster reconstruction,the local government need to actively adjust and adapt to urban spatial planning,so as to leverage the scale effect of large-scale inputs of funds,facilities,human resources and other factors after the disaster,thus enhancing resilience and recovery efficiency in response to disaster impacts.

关键词： Wenchuan earthquake Night-time lights Urban land Post-earthquake reconstruction

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Impacts of artificial dams on terrestrial water storage changes and the Earth's elastic load response during 1950-2016: A case study of medium and large reservoirs in Chinese mainland

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Geodesy and Geodynamics 2024年第3期15卷 252-263页

作者： Linsong Wang mingtao Zhu Yulong Zhong Jianwei Sun Zhenran Peng Hubei Subsurface Multiscale Image Key Laboratory School of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China Three Gorges Research Center for Geo-hazard Ministry of EducationChina University of GeosciencesWuhan 430074China School of Geography and Information Engineering China University of GeosciencesWuhan 430078China

The construction of dams for intercepting and storing water has altered surface water distributions, landsea water exchanges, and the load response of the solid Earth. The lack of accurate estimation of reservoir properties through the land surface and hydrological models can lead to water storage simulation and extraction errors. This impact is particularly evident in many artificial reservoirs in China. The study aims to comprehensively assess the spatiotemporal distribution and trends of water storage in medium and large reservoirs(MLRs) in Chinese mainland during 1950-2016, and to investigate the gravity,displacement, and strain effects induced by the reservoir mass concentration using the load elasticity theory. In addition, the impoundment contributions of MLRs to the relative sea level changes were assessed using a sea-level equation. The results show impoundment increases in the MLRs during1950-2016, particularly in the Yangtze River(Changjiang) and southern basins, causing significant elastic load effects in the surrounding areas of the reservoirs and increasing the relative sea level in China's offshore. However, long-term groundwater estimation trends are overestimated and underestimated in the Yangtze River and southwestern basins, respectively, due to the neglect of the MLRs impacts or the uncertainty of the hydrological model's output(e.g., soil moisture, etc.). The construction of MLRs may reduce the water mass input from land to the ocean, thus slowing global sea level rise. The results of the impact of human activities on the regional water cycle provide important references and data support for improving the integration of hydrological models, evaluating Earth's viscoelastic responses under longterm reservoir storage, enhancing in-situ and satellite geodetic measurements, and identifying the main factors driving sea level changes.

关键词： Man-made dams Terrestrial water storage Elastic load response Sea level changes Chinese mainland

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Evolution of the newest diagnostic methods for COVID-19:a Chinese perspective

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2023年第6期24卷 463-484页

作者： mingtao liu Jiali LYU Xianhui ZHENG Zhiman LIANG Baoying LEI Huihuang CHEN Yiyin MAI Huimin HUANG Baoqing SUN Department of Clinical Laboratory National Center for Respiratory MedicineNational Clinical Research Center for Respiratory DiseaseState Key Laboratory of Respiratory DiseaseGuangzhou Institute of Respiratory Healththe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou510140China National Center for Respiratory Medicine National Clinical Research Center of Respiratory DiseaseState Key Laboratory of Respiratory DiseaseGuangzhou Institute of Respiratory Healththe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou 510140China Guangzhou Medical University Guangzhou 511495China

Coronavirus disease 2019(COVID-19)has continued to spread globally since late 2019,representing a formidable challenge to the world's healthcare systems,wreaking havoc,and spreading rapidly through human contact.With fever,fatigue,and a persistent dry cough being the hallmark symptoms,this disease threatened to destabilize the delicate balance of our global community.Rapid and accurate diagnosis of COVID-19 is a prerequisite for understanding the number of confirmed cases in the world or a region,and an important factor in epidemic assessment and the development of control measures.It also plays a crucial role in ensuring that patients receive the appropriate medical treatment,leading to optimal patient care.Reverse transcription-polymerase chain reaction(RT-PCR)technology is currently the most mature method for detecting viral nucleic acids,but it has many drawbacks.Meanwhile,a variety of COVID-19 detection methods,including molecular biological diagnostic,immunodiagnostic,imaging,and artificial intelligence methods have been developed and applied in clinical practice to meet diverse scenarios and needs.These methods can help clinicians diagnose and treat COVID-19 patients.This review describes the variety of such methods used in China,providing an important reference in the field of the clinical diagnosis of COVID-19.

关键词： Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) Coronavirus disease 2019(COVID-19) Diagnosis Polymerase chain reaction(PCR) Immunoassay Radiography

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Design and test of the key components for a combing-type tobacco harvester

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 145-153页

作者： Chaoran Sun Shaohui Tan Songling Sun mingtao Xiao Limei Chen Wenke Ai Zhihua Qiu Ping Jiang Yang He School of Mechanical and Electrical Engineering Hunan Agricultural UniversityChangsha 410128China Truking Technology Limited Ningxiang 410600HunanChina Construction of tobacco leaf production infrastructure of Hunan Province Company of China National Tobacco Corporation office Changsha 410009China

In response to the problems of low efficiency,high labor intensity,and low mechanization in manual tobacco harvesting,a comb-off tobacco picking device for southern hilly tobacco areas was designed following the agronomic requirements and the principle of manual picking of tobacco harvesting in southern China.The device was composed of the power chassis,picking mechanism,and storage mechanism.This study involved the theoretical analysis,structural design,and modeling of the key components,such as chassis structure,combing-type picking mechanism,and power synchronization mechanism.The results of the motion analysis and calculation of the picking process demonstrated that the adjustment range of the comb chain elevation angles was from 12.4°to 20.9°,the comb rod installation distance was 76.2 mm,and the synchronizing mechanism transmission ratio was 3:10.One-factor test and three-factor three-level orthogonal test was performed with the forward speed of the chassis,the distance between the picking device baffles and the elevation angle of the chain with the combing bar as test factors,and the rate of broken and missed tobacco picking as evaluation indicators.It was revealed that the optimal combination of the forward speed of the chassis,the distance between the baffles,and the chain elevation angle were 1.5 km/h,75 mm,and 12.4°,respectively.Moreover,verification tests suggested that the breakage rate of tobacco leaves was 9.99%,and the probability of missed tobacco picking was 7.31%,both of which satisfy the agriculture requirements and the operational requirements in the agricultural machinery certification syllabus.

关键词： harvesting machinery leaf tobacco combing-type tiered harvest synchronizing mechanism

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Two sex pheromone receptors for sexual communication in the American cockroach

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Science China(Life Sciences) 2024年第7期67卷 1455-1467页

作者： Na Li Renke Dong Huanchao Zeng Yan Zhang Run Huang Wei liu Fengming Cao Jincong Yu mingtao Liao Jingyou Chen Wenlei Zhang Zejian Huang Jiahui Wang Li Li Shen Zhu Danyan Huang Zining Li Xiaoshuai Zhang Dongwei Yuan Nan Chen Yongliang Fan Guirong Wang Coby Schal Yufeng Pan Sheng Li Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology Institute of Insect Science and TechnologySchool of Life SciencesSouth China Normal UniversityGuangzhou 510631China Guangmeiyuan R&D Center Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied TechnologySouth China Normal UniversityMeizhou 514589China Lingnan Guangdong Laboratory of Modern Agriculture Genome Analysis Laboratory of the Ministry of AgricultureAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhen 518000China State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of AgricultureNorthwest A&F UniversityYangling 712100China Department of Entomology and Plant Pathology North Carolina State UniversityRaleigh 27695USA The Key Laboratory of Developmental Genes and Human Disease School of Life Science and TechnologySoutheast UniversityNanjing 210096China

Volatile sex pheromones are vital for sexual communication between males and females.Females of the American cockroach,Periplaneta americana,produce and emit two sex pheromone components,periplanone-A(PA)and periplanone-B(PB).Although PB is the major sex attractant and can attract males,how it interacts with PA in regulating sexual behaviors is still unknown.In this study,we found that in male cockroaches,PA counteracted PB attraction.We identified two odorant receptors(ORs),OR53 and OR100,as PB/PA and PA receptors,respectively.OR53 and OR100 were predominantly expressed in the antennae of sexually mature males,and their expression levels were regulated by the sex differentiation pathway and nutrition-responsive signals.Cellular localization of OR53 and OR100 in male antennae further revealed that two types of sensilla coordinate a complex two-pheromone-two-receptor pathway in regulating cockroach sexual behaviors.These findings indicate distinct functions of the two sex pheromone components,identify their receptors and possible regulatory mechanisms underlying the male-specific and age-dependent sexual behaviors,and can guide novel strategies for pest management.

关键词： sex pheromone odorant receptor sexual attraction sex differentiation cockroach

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基于增量动态逆的协同轨迹控制方法研究

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飞行力学 2024年第1期42卷 70-76页

作者：陈改改刘小雄聂铭涛张珊西北工业大学自动化学院陕西西安710072 陕西省飞行控制与仿真技术重点实验室陕西西安710129 空装驻汉中地区军事代表室陕西汉中723200

针对协同飞行飞机的队形保持和轨迹跟踪问题,提出一种基于增量动态逆的协同轨迹控制方法。首先按照时标分离原理,利用增量动态逆设计飞机航迹控制律;然后使用非线性制导法完成复杂轨迹跟踪控制;接着基于一致性理论,设计4架飞机的长机-... 详细信息

针对协同飞行飞机的队形保持和轨迹跟踪问题,提出一种基于增量动态逆的协同轨迹控制方法。首先按照时标分离原理,利用增量动态逆设计飞机航迹控制律;然后使用非线性制导法完成复杂轨迹跟踪控制;接着基于一致性理论,设计4架飞机的长机-僚机协同飞行轨迹控制律,长机利用L1轨迹制导跟踪期望飞行轨迹,僚机通过基于一致性协议的协同控制律进行队形变换并跟踪长机。仿真结果表明,该方案能够很好地完成协同队形变换和协同轨迹跟踪控制。

关键词：增量动态逆 L1制导一致性协议协同轨迹跟踪

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惯性传感器测试质量质心测量装置及方法研究

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工具技术 2024年第3期58卷 124-131页

作者：梁铭涛张晟刘磊王智中国科学院大学杭州高等研究院基础物理与数学科学学院中国科学院大学中国科学院长春光学精密机械与物理研究所

惯性传感器是空间引力波探测的核心载荷,惯性传感器内的测试质量是惯性和测量基准。测试质量质心、形心偏移会产生杂散力噪声,空间引力波探测对测试质量质心、形心偏移的技术指标要求小于3.75μm。由于需要获得测试质量精确的质心位置,... 详细信息

惯性传感器是空间引力波探测的核心载荷,惯性传感器内的测试质量是惯性和测量基准。测试质量质心、形心偏移会产生杂散力噪声,空间引力波探测对测试质量质心、形心偏移的技术指标要求小于3.75μm。由于需要获得测试质量精确的质心位置,并且商用质心测量装置无法满足测试质量质心测量精度需求,因此设计了一种基于五线摆的新型质心测量装置,根据测得的五线摆自由振动频率得到测试质量质心位置。实验结果表明,质心测量精度优于±1μm,满足空间引力波探测惯性传感器测试质量质心测量的精度需求。

关键词：惯性传感器测试质量质心位置五线摆

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柱形装药空中爆炸冲击波荷载研究

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爆炸与冲击 2024年第4期44卷 60-80页

作者：王明涛程月华吴昊同济大学土木工程学院上海200092

受比例距离、装药长径比、起爆方式、方位角、冲击波入射角以及反射面相对位置等多种因素的影响,球形装药空中爆炸冲击波荷载的计算方法不适用于柱形装药。为探究柱形装药空中自由场爆炸冲击波入射和反射荷载,首先,开展柱形TNT装药单端... 详细信息

受比例距离、装药长径比、起爆方式、方位角、冲击波入射角以及反射面相对位置等多种因素的影响,球形装药空中爆炸冲击波荷载的计算方法不适用于柱形装药。为探究柱形装药空中自由场爆炸冲击波入射和反射荷载,首先,开展柱形TNT装药单端起爆的空中爆炸试验,并基于显式动力学分析软件AUTODYN进行数值模拟,通过与试验和规范进行对比,验证了采用的有限元分析方法的适用性。进一步开展考虑比例距离、长径比、起爆方式、方位角和刚性反射等因素的1000余组柱形装药空中爆炸工况的数值模拟。基于模拟结果,揭示了柱形装药空中爆炸入射冲击波峰值超压和最大冲量及其形状因子的分布特征,提出峰值超压和最大冲量临界比例距离的判定准则和确定方法,阐明了刚性反射冲击波峰值超压和反射系数的变化规律。最后,提出柱形装药空中爆炸入射和反射冲击波荷载的计算方法,并得到360余组试验数据的验证。该方法可快速计算作用于建筑结构上的爆炸荷载,并为弹药毁伤效能评估、结构动态响应和破坏分析及其抗爆设计提供参考。

关键词：柱形装药空中爆炸峰值超压最大冲量临界比例距离

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一种新型二级凸轮式分度机构动力学仿真

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机械设计 2024年第2期41卷 96-101页

作者：刘明涛袁胜男陈港郭天明天津科技大学机械工程学院天津300222

针对一种新型二级凸轮式分度机构的拓扑结构特点,在ADAMS软件环境下建立了机构动力学模型,分析机构的输出响应。在此基础上,研究了转速、惯性负载及针齿分度圆半径等因素对整机动态性能的影响规律。此外,分析了传动构件的针齿强度。结... 详细信息

针对一种新型二级凸轮式分度机构的拓扑结构特点,在ADAMS软件环境下建立了机构动力学模型,分析机构的输出响应。在此基础上,研究了转速、惯性负载及针齿分度圆半径等因素对整机动态性能的影响规律。此外,分析了传动构件的针齿强度。结果表明:机构输出轴角速度值随着转速的提高而大幅度增加,随着针齿分度圆半径的增大而减小,其波动幅值随负载的增大而明显减小。机构分度期内针齿与凸轮间的动态啮合力显著波动,上述研究成果可为该类分度机构的工况参数选择原则提供一定的参考。

关键词：行星式凸轮分度机构拓扑结构虚拟样机动力学分析

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