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Thermohaline intrusions in the thermocline of the western tropical Pacific Ocean

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Acta Oceanologica Sinica 2013年第7期32卷 47-56页

作者： li yuanlong WANG Fan Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences Graduate University of Chinese Academy of Science

The existing high-resolution hydrographic data in the western tropical Pacilit; Ocean are used to explore the spatial distribution and primary characteristics of thermohaline intrusions in the thermocline. Statistics show that the vertical scales of intrusions are 20-40 m in the upper thermocline （22.0-26.0δ0） and 40-80 m in the lower thermocline （26.0-27.2δ0）. In the upper thermocline, the most intensive intrusions exist at the equatorial front （EF） where north/sonth Pacilic water masses converge, anti Ihe westward spreading of the north Pacilic tropical waler （NPTW） in the Philippines Sea also produces patches of intrusions surrounding its high-salinity tongue. In the lower thermocline, intrusions are also strong at the tropical front （TF） which is the boundary between the north Pacilic subtropical/tropical waters. At the bottom of the thermocline （at about 27.0δ0）, intrusions mainly exist near the western boundary, which are produced by intermediate water convergence through the advection of subthermocline western boundary Ilows. Most strikingly a ＂C＂-shape distribution of intrusions at around 26.4δ0 is revealed, covering the vicinity of the EF the TE and the Mindanao Current （MC）, i.e., tile western boundary pathway ol the norlh Pacilic subtrnpical cell （STC）. Synoptic section analysis reveals that intrusions are more prominent on the warm/sally flank ot the fronts, implying more cross-front tongues of cold/fresh water. Among the intrusions, those at the EF are of best lateral coherence which implies a unique driving mechanism involving near-inertial velocity perturbations near the equator.

关键词： thermohaline intrusions thermocline water mass western tropical Pacilic

Global practical stabilization of the double integrator system with an imperfect sensor and subject to a bounded disturbance

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Control Theory and Technology 2024年第3期22卷 468-478页

作者： Zhiyuan Zhu yuanlong li Zongli lin Department of Automation Shanghai Jiao Tong Universityand Key Laboratory of System Control and Information Processing of Ministry of EducationShanghai 200240China Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaP.0.Box 400743CharlottesvilleVA 22904-4743USA

This paper is concerned with global practical stabilization of the double integrator system with an imperfect sensor and subject to an additive bounded output *** imperfect sensor nonlinearity possesses the nonlinear characteristics of saturation and dead *** of the presence of output dead zone and the additive disturbance,the states cannot be expected to driven into an arbitrarily small neighborhood of the *** solve the global practical stabilization problem,we proposes a low gain-based linear dynamic output feedback law,under which the first state enters and remains in a bounded set whose size is depended on the bound of disturbance and the range of dead zone and the second state enters and remains in a pre-specified arbitrarily small set,both in finite *** results illustrate the effectiveness of our proposed control method.

关键词： Output saturation Disturbance rejection Output dead zone Low gain feedback-linear output feedback Practical stabilization

Subtropical sea surface salinity maxima in the South Indian Ocean

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Journal of Oceanology and limnology 2020年第1期38卷 16-29页

作者： WANG Yu li yuanlong WEI Chuanjie North China Sea Off shore Engineering Survey Institute North China Sea Branch of Ministry of Natural ResourcesQingdao 266061China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China Engineering and Technology Department Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China

Subtropical sea surface salinity(SSS)maximum is formed in the subtropical South Indian Ocean(SIO)by excessive evaporation over precipitation and serves as the primary salt source of the *** SSS measurements by Aquarius satellite during September 2011-May 2015 detect three disconnected SSS maximum regions(>35.6)in the eastern(105°E-115°E,38°S-28°S),central(60°E-100°E,35°S-25°S),and western(25°E-40°E,38°S-20°S)parts of the subtropical SIO,*** structure is however not seen in gridded Argo *** of Argo profile data confirms the existence of the eastern maximum patch and also reveals SSS overestimations of Aquarius near the western and eastern *** subjected to large uncertainties,a mixed-layer budget analysis is employed to explain the seasonal cycle of *** eastern and central regions reach the highest salinity in February-March and lowest salinity in August-September,which can be well explained by surface freshwater forcing(SFF)*** is however not controlled by evaporation(E)or precipitation(P).Instead,the large seasonal undulations of mixed layer depth(MLD)is the key *** shallow(deep)MLD in austral summer(winter)amplifies(attenuates)the forcing effect of local positive E-P and causes SSS rising(decreasing).Ocean dynamics also play a ***,activity of mesoscale eddies is a critical factor regulating SSS variability in the eastern and western regions.

关键词： sea surface salinity(SSS) subtropical salinity maximum Aquarius Argo float freshwater flux

Semi-global weighted output average tracking of discrete-time heterogeneous multi-agent systems subject to input saturation and external disturbances

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Control Theory and Technology 2023年第3期21卷 315-333页

作者： Qilin Song yuanlong li Yijing Xie Zongli lin Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Department of Electrical Engineering University of Texas at ArlingtonArlington 76019TXUSA Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaCharlottesville 22904-4743VAUSA

In this paper,we revisit the semi-global weighted output average tracking problem for a discrete-time multi-agent system subject to input saturation and external *** multi-agent system consists of multiple heterogeneous linear systems as leader agents and multiple heterogeneous linear systems as follower *** design both the state feedback and output feedback control protocols for each follower *** particular,a distributed state observer is designed for each follower agent that estimates the state of each leader *** the output feedback case,state observer is also designed for each follower agent to estimate its own *** these estimates,we design low gain-based distributed control protocols,parameterized in a scalar low gain *** is shown that,for any bounded set of the initial conditions,these control protocols cause the follower agents to track the weighted average of the outputs of the leader agents as long as the value of the low gain parameter is tuned sufficiently *** results illustrate the validity of the theoretical results.

关键词： Distributed average tracking Input saturation Low gain feedback Heterogeneous multi-agent systems Output regulation

Spatial-temporal variability of thermohaline intrusions in the northwestern tropical Pacific Ocean

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Chinese Science Bulletin 2013年第9期58卷 1038-1043页

作者： li yuanlong WANG Fan TANG XiaoHui Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences

Using repeated hydrographic measurements at 137°E,spatial-temporal variability of thermohaline intrusions in the northwestern tropical Pacific are *** can be found in the main thermocline throughout the section,with their strength decreasing rapidly *** strongest intrusions exist at the North Equatorial Countercurrent(NECC) where North/South Pacific thermocline water *** intrusions also exhibit temporal variations in strength which are closely associated with the meridional displacement of the *** strength peaks in boreal winter when the NECC reaches its northernmost position of the *** interannual time scale,intrusions tend to be weak(strong) during El Ni o(La Ni a) *** in intrusion strength also lead to prominent fluctuation of lateral diffusivity K L and cross-front temperature flux F Θ.F Θ exhibits significant year-to-year changes which are well correlated with ENSO index,suggesting a possible role of intrusions in the low-latitude Pacific climate variability.

关键词：西北太平洋热带海洋入侵时空变异温盐水文测量时空变化重复使用

Regional Leader-following Consensus of Multi-agent Systems with Saturating Actuators 36

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Regional Leader-following Consensus of Multi-agent Systems w...

Intraseasonal variability of the surface zonal current in the equatorial Indian Ocean:Seasonal differences and causes

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作者： yuanlong li Zongli lin Department of Automation Shanghai Jiao Tong Universityand Key Laboratory of System Control and Information Processing of Ministry of Education Charles L.Brown Department of Electrical and Computer Engineering University of Virginia

ISBN: (纸本)9781538629185

For a linear system that has a pole in the open right-half plane and is subject to actuator saturation,global asymptotically stabilization cannot be *** a result,a multi-agent system containing such an actuator saturating agent can only reach regional consensus,that is,consensus can be achieved only when the initial state of each agent resides in a region of the state *** region of all these initial states is referred to as the domain of *** general,the domain of consensus cannot be exactly *** this paper,we consider the problem of estimating the domain of consensus of a multi-agent system with an agent subject to actuator saturation.A set of necessary and sufficient conditions under which an ellipsoidal set can be used as an estimate of the domain of consensus are *** on these conditions,an LMI-based optimization problem is formulated for obtaining the largest ellipsoidal estimate of the domain of *** results illustrate the effectiveness of the proposed approach and show the relationship between the size of the largest ellipsoidal estimate and the communication topology of the multi-agent system.

关键词： Multi-agent systems actuator saturation regional consensus domain of consensus

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Acta Oceanologica Sinica 2022年第5期41卷 12-26页

作者： Qingwen Zhong Gengxin Chen yuanlong li Qihua Peng Xiaoqing Chu State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou511458China University of Chinese Academy of Sciences Beijing100049China Innovation Academy of South China Sea Ecology and Environmental Engineering Chinese Academy of SciencesGuangzhou510075China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao266237China

Using observations and numerical simulations,this study examines the intraseasonal variability of the surface zonal current(u ISV)over the equatorial Indian Ocean,highlighting the seasonal and spatial differences,and the causes of the ***-amplitude u ISV occurs in the eastern basin at around 80°–90°E and near the western boundary at 45°–55°*** the eastern basin,the u ISV is mainly caused by the atmospheric intraseasonal oscillations(ISOs),which explains 91%of the standard deviation of the total u *** analysis suggests that it takes less than ten days for the intraseasonal zonal wind stress to generate the u ISV through the directly forced Kelvin and Rossby *** by the stronger zonal wind stress associated with the Indian summer monsoon ISO(MISO),the eastern u ISV in boreal summer(May to October)is about 1.5 times larger than that in boreal winter(November to April).In the western basin,both the atmospheric ISOs and the oceanic internal instabilities contribute substantially to the u ISV,and induce stronger u ISV in boreal *** budget analysis suggests that the mean flow converts energy to the intraseasonal current mainly through barotropic instabilities.

关键词： equatorial zonal current intraseasonal variability seasonal difference wind stress associated with the MISO and MJO

CBCT引导下头颈肩联合腹膜固定方式在乳腺癌IMRT中的临床适用性研究

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中国医疗设备 2025年第1期40卷 47-51,64页

作者：袁维杨泽李元龙魏英王纪全西安交通大学第一附属医院肿瘤放疗科陕西西安710061 西安交通大学第一附属医院榆林医院肿瘤放疗科陕西榆林719000

目的基于锥形束CT(Cone Beam CT,CBCT)影像比较头颈肩联合腹膜体位固定方式和乳腺托架体位固定方式的摆位误差,研究头颈肩联合腹膜在乳腺癌患者调强放射治疗(Intensity Modulated Radiotherapy,IMRT)中体位固定方法的可行性。方法选取... 详细信息

目的基于锥形束CT(Cone Beam CT,CBCT)影像比较头颈肩联合腹膜体位固定方式和乳腺托架体位固定方式的摆位误差,研究头颈肩联合腹膜在乳腺癌患者调强放射治疗(Intensity Modulated Radiotherapy,IMRT)中体位固定方法的可行性。方法选取需要进行IMRT的40例乳腺癌患者为研究对象,并将其随机分成头颈肩联合腹膜固定组(20例)、乳腺托架固定组(20例)。每例患者在放射治疗(以下简称“放疗”)前行CBCT扫描,每周1次,分析2组患者在X(左右)、Y(进出)、Z(前后)方向的摆位误差、分次间位移和摆位效率。结果头颈肩联合腹膜和托架摆位2组患者在X、Y、Z方向上的摆位误差分别为(1.97±0.94)和(2.11±1.55)mm、(2.54±0.57)和(2.82±1.46)mm、(1.27±0.62)和(2.28±0.96)mm(P=0.801、0.604、0.013);分次间位移分别为(0.76±0.50)和(1.24±0.52)mm、(1.34±0.15)和(2.52±1.18)mm、(0.73±0.33)和(0.88±0.53)mm(P=0.453、0.296、0.773);摆位时间分别为(6.5±1.7)和(8.7±3.1)min(P=0.485);2组X、Y、Z方向上的首次摆位通过率分别为90%和85%、80%和70%、100%和95%(P=0.632、0.464、0.235);分次间摆位通过率为92%和82%、88%和79%、94%和88%(P=0.036、0.086、0.138)。结论头颈肩联合腹膜体位固定方式简单易行,可在一定程度上控制乳腺癌患者IMRT的摆位误差和分次间位移,尤其是Z方向上的摆位误差,提高摆位效率。

关键词：乳腺癌头颈肩联合腹膜乳腺托架摆位误差摆位通过率调强放射治疗(IMRT) 锥形束CT(CBCT)

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保护用电流互感器暂态特性的工程计算

电力系统自动化 2000年第11期24卷 49-51页

作者：李元龙东北电力设计院长春130021

电流互感器暂态误差的工程校验计算在目前还没有通用的计算准则和计算方法。考虑电流互感器暂态特性 ,如何确定电流互感器的型式及有关参数 (包括电力系统和电流互感器的参数、电流互感器的负载 )是电力系统运行和工程设计迫切需要解决... 详细信息

电流互感器暂态误差的工程校验计算在目前还没有通用的计算准则和计算方法。考虑电流互感器暂态特性 ,如何确定电流互感器的型式及有关参数 (包括电力系统和电流互感器的参数、电流互感器的负载 )是电力系统运行和工程设计迫切需要解决的问题。

关键词：电流互感器短路电流工程计算电力系统