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Vortex-Induced Vibration Response Features of A Submarine Multi-Span Pipeline via Towing Tank Experimental Tests

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China Ocean Engineering 2023年第2期37卷 175-189页

作者： XU Wan-hai JIA Kun ma ye-xuan SONG Zhi-you State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

In offshore engineering, the phenomenon of free span often occurs, and the pipeline may have multiple free spans adjacent to each other, forming a multi-span pipeline. The interaction of different spans makes the structural vibration characteristics more complex, which may change the fatigue characteristics of the pipeline and affect the safety of the structure. In this paper, model tests were designed to explore the vortex-induced vibration(VIV) characteristics of multi-span pipelines and investigate the multi-span interaction mechanism. The experimental study mainly focused on the dynamic response of double-span pipelines, and further extended to triple-span pipelines, hoping that the results can be applied to more complex environment. The effects of span-length ratio, buried depth and axial force on VIV of the pipeline were investigated and discussed. The dynamic response of the pipeline varied with the span length. There was obvious interaction between different spans of multi-span pipelines, and the pipe-sediment interaction obviously affected the vibration characteristics of pipeline. The differences of pipeline burial depth and axial force changed the structural stiffness. With the increase of buried depth, the response amplitude presented a downward trend. The spanwise evolutions were asymmetric caused by the pipe-sediment interaction and multi-span interaction. The results can help to identify multi-span pipelines in engineering, and realize the prevention and control of free spans.

关键词： vortex-induced vibration submarine pipeline pipe-sediment interaction multi-span interaction

Displacement Response Reconstruction of Slender Flexible Structures Based on Cubic Spline Fitting Method

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China Ocean Engineering 2019年第2期33卷 226-236页

作者： HAN Qing-hua ma ye-xuan FENG Xin-xin XU Wan-hai State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University School of Civil Engineering Tianjin University

How to reconstruct a dynamic displacement of slender flexible structures is the key technology to develop smart structures and structural health monitoring(SHM), which are beneficial for controlling the structural vibration and protecting the structural safety. In this paper, the displacement reconstruction method based on cubic spline fitting is put forward to reconstruct the dynamic displacement of slender flexible structures without the knowledge of modeshapes and applied loading. The obtained strains and displacements are compared with the results calculated by ABAQUS to check the method's validity. It can be found that the proposed method can accurately identify the strains and displacement of slender flexible structures undergoing linear vibrations, nonlinear vibrations, and parametric vibrations. Under the concentrated force, the strains of slender flexible structures will change suddenly along the axial direction. With locally densified measurement points, the present reconstruction method still works well for the strain concentration problem.

关键词： displacement reconstruction cubic spline fitting slender flexible structures linear vibrations parametric vibrations nonlinear vibrations

Characterization of size-resolved aerosol hygroscopicity and liquid water content in Nanjing of the Yangtze River Delta

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Journal of Environmental Sciences 2025年第5期151卷 26-41页

作者： Youling Jiang Yan ma Jun Zheng Nan ye Cheng Yuan School of Environmental Science and Engineering Nanjing University of Information Science and TechnologyNanjing 210044China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Nanjing University of Information Science&TechnologyNanjing 210044China School of Emergency management Nanjing University of Information Science&TechnologyNanjing 210044China

Aerosol hygroscopicity and liquid water content(ALWC)have important influences on the environmental and climate effect of *** this study,we measured the hygroscopic growth factors(GF)of particles with dry diameters of 40,80,150,and 200 nm during the wintertime in *** the GF-derived hygroscopicity parameter(κ_(gf))and ALWC increased with particle size,but displayed differing diurnal variations,withκ_(gf)peaking around the midday,while ALWC peaking in the early ***,ammonium and oxygenated organic aerosols(OOA)were found as the chemical components mostly strongly correlated with ALWC.A closure study suggests that during midday photo-oxidation and nighttime high ALWC periods,theκof organic aerosols(κ_(org))was underestimated when using previous ***,we re-constructed parameterizations forκ_(org)and the oxidation level of organics for these periods,which indicates a higher hygroscopicity of photochemically formed OOA than the aqueous OOA,yet both being much higher than the generally assumed OOA ***,in a typical high ALWC episode,concurrently increased ALWC,nitrate,OOA as well as aerosol surface area and mass concentrations were observed under elevated ambient *** strongly indicates a coupled effect that the hygroscopic secondary aerosols,in particular nitratewith strong hygroscopicity,led to large increase in ALWC,which in turn synergistically boosted nitrate and OOA formation by heterogeneous/aqueous *** interaction may represent an important mechanism contributing to enhanced formation of secondary aerosols and rapid growth of fine particulate matter under relatively high RH conditions.

关键词： Aerosol hygroscopicity Aerosol liquid water content Photo-oxidation Aqueous/heterogeneous reactions

Effect of cholesterol metabolism on hepatolithiasis

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World Journal of Gastroenterology 2025年第1期31卷 157-162页

作者： Lin Zheng Zi-Yu ye Jun-Ji ma Department of Gastroenterology The Second Hospital of Hebei Medical UniversityHebei Key Laboratory of GastroenterologyHebei Institute of GastroenterologyHebei Clinical Research Center for Digestive DiseasesNo.215 Heping West RoadShijiazhuang 050000Hebei ProvinceChina

Surgical intervention is currently the primary treatment for hepatolithiasis;how-ever,some patients still experience residual stones and high recurrence rates after *** metabolism seems to play an important role in hepatoli-thiasis pathogenesis.A high cholesterol diet is one of the significant reasons for the increasing incidence of ***,regular diet and appropriate medical intervention are crucial measures to prevent hepatolithiasis and reduce recurrence rate after *** dietary cholesterol and drugs that increase cholesterol stone solubility are key therapeutic approaches in treating *** article discusses the cholesterol metabolic pathways related to the pathogenesis of hepatolithiasis,as well as food intake and targeted therapeutic drugs.

关键词： Hepatolithiasis Cholesterol metabolism High-fat diet 3-hydroxy-3-methylglutaryl-coenzyme A reductase Interlobular bile duct

带有中心钝体的固体燃料冲压发动机工作性能分析

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推进技术 2022年第8期43卷 40-47页

作者：张宁史金光王中原马晔璇南京理工大学能源与动力学院江苏南京210094 北京动力机械研究所北京100074

为提高固体燃料冲压发动机的燃烧特性和工作性能,提出了带有中心钝体的固体燃料冲压发动机方案,基于雷诺转捩和涡概念耗散方程建立了其湍流燃烧模型,并数值计算分析了其内流场、燃面退移速率、推力与总压损失。结果表明:带有中心钝体的... 详细信息

为提高固体燃料冲压发动机的燃烧特性和工作性能,提出了带有中心钝体的固体燃料冲压发动机方案,基于雷诺转捩和涡概念耗散方程建立了其湍流燃烧模型,并数值计算分析了其内流场、燃面退移速率、推力与总压损失。结果表明:带有中心钝体的冲压发动机内部流动过程较为复杂,钝体后部有四个漩涡,增强了发动机内来流空气与燃气的掺混;钝体孔隙中的高速气流与两侧的小尺度漩涡保证了钝体尾涡的稳定性;与普通固体燃料冲压发动机相比,在燃烧室中增加中心钝体能增大燃烧室内高温区面积,提高补燃室内温度,可使推进剂平均燃面退移速率提高36.5%,发动机推力提高22.1%,燃烧效率提高8.9%。

关键词：固体燃料冲压发动机涡旋燃烧燃面退移速率推力燃烧效率

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含铝固体燃料冲压发动机工作性能分析

推进技术 2022年第6期43卷 49-57页

作者：张宁史金光王中原马晔璇南京理工大学能源与动力学院江苏南京210094 北京动力机械研究所北京100074

为探究含铝固体燃料冲压发动机的燃烧特性和工作性能,基于纳米铝颗粒和端羟基聚丁二烯(HTPB)的混合固体燃料,采用雷诺转捩模型、颗粒表面反应模型和涡概念耗散模型,建立了二维两相湍流燃烧模型;数值计算分析了含铝固体燃料冲压发动机内... 详细信息

为探究含铝固体燃料冲压发动机的燃烧特性和工作性能,基于纳米铝颗粒和端羟基聚丁二烯(HTPB)的混合固体燃料,采用雷诺转捩模型、颗粒表面反应模型和涡概念耗散模型,建立了二维两相湍流燃烧模型;数值计算分析了含铝固体燃料冲压发动机内流场,以及不同含铝质量分数和粒径下的燃面退移速率、推力与比冲。结果表明:发动机的进气条件对颗粒相的燃烧与运动起主导作用;与纯HTPB推进剂相比,添加质量分数为5%的铝颗粒能够提高补燃室压强和温度,增大燃烧室内高温区面积,可使推进剂平均燃面退移速率提高18.53%,发动机推力提高21.37%,密度比冲提高2.38%,适当增加铝颗粒含量或减小粒径,对提高推进剂燃面退移速率、发动机推力和密度比冲具有积极作用。

关键词：固体燃料冲压发动机含铝推进剂燃面退移速率推力比冲

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Life-Cycle Bearing Capacity for Pre-Stressed T-beams Based on Full-Scale Destructive Test

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Structural Durability & Health Monitoring 2025年第1期19卷 145-166页

作者： Yushan ye Tao Gao Liankun Wang Junjie ma Yingchun Cai Heng Liu Xiaoge Liu China Construction Seventh Engineering Division Corp. Ltd.Zhengzhou450004China School of Water Conservancy and Transportation Zhengzhou UniversityZhengzhou450001China

To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete *** on the measurement and ana-lysis of beam deﬂection,strain,and crack development under various loading levels during the research tests,combined with the veriﬁcation coefﬁcient indicators speciﬁed in the codes,the veriﬁcation coefﬁcients of bridges at different stages of damage can be *** results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test *** the complete linear elastic stage,both the deﬂection and bottom strain veriﬁcation coefﬁcients comply with the speciﬁcations,indicating a good structural load-bearing capacity no longer adheres to the code’s *** the non-linear stage,both coefﬁcients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing *** to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s speciﬁed *** strain veriﬁcation coefﬁcient sourced from the compression zone at the bottom of theﬂange is not recommended for assessing the bridge’s load-bearing capacity.

关键词： Pre-stressed T-beams whole process destructive test bearing capacity veriﬁcation coefﬁcient

Climate changes drive phytoplankton community through complementarity and selection effects in a large mesotrophic reservoir

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Journal of Oceanology and Limnology 2025年第1期43卷 119-133页

作者： Yue WU Qi ye Siwen CHEN Lei JIANG Kaining CHEN Shuzhan ma Yiheng CHANG Jie LIU Xiaoli SHI State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China College of Nanjing University of Chinese Academy of SciencesNanjing 211135China China State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River Jiangsu Provincial Academy of Environmental ScienceNanjing 210036China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China

Understanding the response of the phytoplankton community to climate change is essential for reservoir *** analyzed a long-term data series(2009–2020)on the phytoplankton community in a large mesotrophic reservoir in the wet season to investigate the impacts of temperature and precipitation increases caused by climate change on the functioning and trait composition of the phytoplankton *** the last twelve years,the 3-month accumulative precipitation increased from 291.03 mm to 590.91 mm,and the surface water temperature increased from 25.06℃to 26.49℃in wet season,*** changes caused a higher water level,stronger thermal stratification and lower nitrogen concentration in Daxi *** dynamic equilibrium model indicated that the increased precipitation and water temperature-related environmental changes would result in a more diverse and productive phytoplankton *** effects of increasing water temperature and precipitation on the niche complementarity and selection effects within the phytoplankton community were analyzed using structural equation model by means of the functional divergence index and functional evenness index,respectively,elucidating the reasons for the increase in cyanobacteria in the absence of a significant increase in nutrient *** on these results,it is advisable that more stringent phosphorus control standards might be conducted to reduce the risks of cyanobacteria proliferation in the context of global warming.

关键词： global warming climate change reservoir trait-based phytoplankton functional group cyanobacteria

Early prediction cardiac arrest in intensive care units:the value of laboratory indicator trends

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World Journal of Emergency Medicine 2025年第1期16卷 67-70页

作者： Wentao Sang Jiaxin ma xuan Zhang Shuo Wu Chang Pan Jiaqi Zheng Wen Zheng Qiuhuan Yuan Jian Zhang Jingjing ma Feng Xu Department of Emergency Medicine Qilu HospitalShandong UniversityJinan 250012China Chest Pain Center Qilu HospitalShandong UniversityJinan 250012China Shandong Provincial Clinical Research Center for Emergency and Critical Care Medicine Institute of Emergency and Critical Care Medicine of Shandong UniversityQilu HospitalShandong UniversityJinan 250012China Key Laboratory of Emergency and Critical Care Medicine of Shandong Province Key Laboratory of Cardiopulmonary-Cerebral Resuscitation Research of Shandong ProvinceShandong Provincial Engineering Laboratory for Emergency and Critical Care MedicineQilu HospitalShandong UniversityJinan 250012China Key Laboratory of Cardiovascular Remodeling and Function Research Chinese Ministry of EducationChinese Ministry of Health and Chinese Academy of Medical Sciencesthe State and Shandong Province Joint Key Laboratory of Translational Cardiovascular MedicineQilu HospitalShandong UniversityJinan 250012China

The incidence of in-hospital cardiac arrest (IHCA) has increased over the past decade,with more than half occurring in intensive care units (ICUs).^([1])ICU cardiac arrest (ICU-CA)presents unique challenges,with worse outcomes than those in monitored wards,highlighting the need for early detection and intervention.^([2])Up to 80%of patients exhibit signs of deterioration hours before IHCA.^([3])Although early warning scores based on vital signs are useful,their eff ectiveness in ICUs is limited due to abnormal physiological parameters.^([4])Laboratory markers,such as sodium,potassium,and lactate,are predictive of poor outcomes,^([5])but static measurements may not capture the patient’s *** in laboratory indicators,such as variability and extremes,may offer better predictive value.^([6])This study aimed to evaluate ICU-CA predictive factors,with a focus on vital signs and trends of laboratory indicators.

关键词： prediction signs arrest