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Physical mechanism of the rapid increase in intense and long-lived extreme heatwaves in the Northern Hemisphere since 1980

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Science China Earth Sciences 2024年第7期67卷 2103-2121页

作者： Yuqing WANG Wen zhou Chunzai WANG Key Laboratory of Polar Atmosphere-ocean-ice System for Weather and Climate of the MOE Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric SciencesFudan UniversityShanghai 200438China Key Laboratory for Polar Science of the MNR Polar Research Institute of ChinaShanghai 201209China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Global Ocean and Climate Research Center South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China

Since 1980,both the intensity and duration of summer heatwaves in the middle and high latitudes of the Northern Hemisphere have significantly increased,leading this region to become a critical area for a significant increase in the frequency of intense and long-lived extreme *** found that stronger and more persistent high-pressure systems and lower soil moisture before the events were the main drivers of intense and long-lived extreme heatwaves in western Europe and the middle and high latitudes of North ***,in eastern Europe and Siberia,lower cloud cover before events is also a main driver of this type of extreme heatwave,in addition to the above *** factors are coupled with each other and can change heatwave intensity and duration by influencing surface radiation processes during *** the self-organizing map classification method,we found that 6 weather patterns with increased frequency,intensity,and duration were the main dynamic reasons leading to the increase in intense and long-lived extreme heatwaves after *** addition,the decrease in summer average soil moisture in most areas of the mid-high latitudes of the Northern Hemisphere and the decrease in average cloud cover in eastern Europe and Siberia are found to be the main thermodynamic reasons leading to the increase in these extreme heatwaves.

关键词： High intensity Long duration Extreme heatwaves High pressure system Soil moisture Cloud cover

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Enhancing SAEAs with unevaluated solutions:a case study of relation model for expensive optimization

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Science China(Information Sciences) 2024年第2期67卷 41-58页

作者： Hao HAO Xiaoqun ZHANG Aimin zhou Institute of Natural Sciences Shanghai Jiao Tong University Shanghai Frontiers Science Center of Molecule Intelligent Syntheses School of Computer Science and Technology East China Normal University

Surrogate-assisted evolutionary algorithms(SAEAs) hold significant importance in resolving expensive optimization problems. Extensive efforts have been devoted to improving the efficiency of SAEAs through the development of proficient model-assisted solution selection methods, which, however, first requires generating high-quality solutions. The fundamental paradigm of evaluating a limited number of solutions in each generation within SAEAs reduces the variance of adjacent populations, thereby affecting the quality of offspring solutions. This is a frequently encountered issue yet receives little attention. To address the issue, this paper presents a framework using unevaluated solutions to enhance the efficiency of *** surrogate model is employed to identify high-quality solutions for the direct generation of new solutions without evaluation. To ensure dependable selection, we have introduced two tailored relation models to select the optimal solution and the unevaluated population. A comprehensive experimental analysis is performed on two test suites, which showcases the superiority of the relation model over regression and classification models in the solution selection phase. Furthermore, the surrogate-selected unevaluated solutions with high potential have been shown to enhance the efficiency of the algorithm significantly.

关键词： expensive optimization unevaluated solutions relation model surrogate-assisted evolutionary algorithm

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Monitoring shear deformation of sliding zone via fiber Bragg grating and particle image velocimetry

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 231-241页

作者： Deyang Wang Honghu Zhu Guyu zhou Wenzhao Yu Baojun Wang Wanhuan zhou School of Earth Sciences and Engineering Nanjing UniversityNanjing210023China Institute of Earth Exploration and Sensing Nanjing UniversityNanjing210023China State Key Laboratory of Internet of Things for Smart City University of MacaoMacaoChina

Monitoring shear deformation of sliding zones is of great significance for understanding the landslide evolution mechanism,in which fiber optic strain sensing has shown great ***,the cor-relation between strain measurements of quasi-distributed fiber Bragg grating(FBG)sensing arrays and shear displacements of surrounding soil remains *** this study,a direct shear model test was conducted to simulate the shear deformation of sliding zones,in which the soil internal deformation was captured using FBG strain sensors and the soil surface deformation was measured by particle image velocimetry(PIV).The test results show that there were two main slip surfaces and two secondary ones,developing a spindle-shaped shear band in the *** formation of the shear band was successfully captured by FBG sensors.A sinusoidal model was proposed to describe the fiber optic cable deformation *** this basis,the shear displacements and shear band widths were calculated by using strain *** work provides important insight into the deduction of soil shear deformation using soil-embedded FBG strain sensors.

关键词： Landslide Shear band Fiber bragg grating(FBG) Particle image velocimetry(PIV) Sinusoidal model Strain‒displacement proportional coefficient

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Regional climate response to global warming in the source region of the Yellow River and its impact on runoff

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Science China Earth Sciences 2024年第3期67卷 843-855页

作者： Yiran ZHANG Degang zhou Xiaofeng GUO Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The source region of the Yellow River has experienced obvious climate and discharge changes in recent decades due to global warming, which largely affects the water resources and ecological and environmental security in the Yellow River basin. This study analyzed the changes in runoff and several climate factors in the source region of the Yellow River based on the observed discharges at the Tangnag hydrological station, routine meteorological data from China Meteorological Administration(CMA) stations within and near this source region, and several evaporation datasets. The results indicate that the runoff in the source region was relatively abundant from 1960 to 1989 and then declined sharply afterward. It recovered slightly after 2005 but was still below normal—10% less than that during 1960–1989. Similarly, the precipitation amounts in the source region were relatively low in the 1990s, but they increased significantly after 2003, with an average increase of 31.4 mm or 6% more when compared to that in 1960–1989. In addition, the temperatures in the source region continued to rise from 1960 to 2017, and the evaporation levels also showed an upward trend after 1990. The influences of the spatial and temporal variations in climatic factors on runoff in the source region were then further analyzed. The results indicate that the decreases in precipitation and the number of days of heavy rainfall in the source region from 1990 to 2002 were important reasons for the lower runoff during this period. After 2003, the precipitation in the southeastern part of the source region, which is a key area for runoff generation,increased only to a limited extent, but the evaporation in the entire source region generally increased with increasing temperature,which might have led to the low capacity for actual runoff production in each subbasin and persistent low runoff in the source region. Therefore, such a climate response to global warming in the source region might be unfavorabl

关键词： The source region of the Yellow River Climate response Runoff variation Evaporation Precipitation

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Bivariate attribution of the compound hot and dry summer of 2022 on the Tibetan Plateau

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Science China Earth Sciences 2024年第7期67卷 2122-2136页

作者： Baiquan zhou Panmao ZHAI Zhen LIAO State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081China

The extraordinarily high temperatures experienced during the summer of 2022 on the Tibetan Plateau(TP)demand attention when compared with its typical climatic *** absence of precipitation alongside the elevated temperatures resulted in 2022 being the hottest and driest summer on record on the TP since at least *** the susceptibility of the TP to climate change,this study employed large-ensemble simulations from the HadGEM3-A-N216 attribution system,together with a copula-based joint probability distribution,to investigate the influence of anthropogenic forcing,primarily global greenhouse gas emissions,on this unprecedented compound hot and dry event(CHDE).Findings revealed that the return period for the 2022 CHDE on the TP exceeds 4000 years,as determined from the fitted joint distributions derived using observational data spanning *** CHDE was directly linked to large-scale circulation anomalies,including the control of equivalent-barotropic high-pressure anomalies and the northward displacement of the subtropical westerly jet ***,anthropogenic forcing has,to some extent,promoted the surface warming and increased variability in precipitation on the TP in summer,establishing conditions conducive for the 2022 CHDE from a long-term climate change *** return period for a 2022-like CHDE on the TP was estimated to be approximately 283 years(142-613 years)by the large ensemble forced by both anthropogenic activities and natural ***,ensemble simulations driven solely by natural forcing indicated that the likelihood of occurrence of a 2022-like CHDE was almost *** outcomes underscore that the contribution of anthropogenic forcing to the probability of a 2022-like CHDE was 100%,implying that without anthropogenically induced global warming,a comparable CHDE akin to that observed in 2022 on the TP would not be possible.

关键词： Compound hot and dry event Tibetan Plateau Bivariate event attribution Anthropogenic forcing

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Westerlies Affecting the Seasonal Variation of Water Vapor Transport over the Tibetan Plateau Induced by Tropical Cyclones in the Bay of Bengal

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Advances in Atmospheric Sciences 2024年第5期41卷 881-893页

作者： Xiaoli zhou Wen zhou Dongxiao WANG Qiang XIE Lei YANG Qihua PENG Key Laboratory of Polar Atmosphere-ocean-ice System for Weather and Climate Ministry of Education&Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric SciencesFudan UniversityShanghai 200438China School of Marine Sciences Sun Yat-Sen UniversityZhuhai 519082China Institute of Deep-sea Science and Engineering Chinese Academic SciencesSanya 572000China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academic ScienceGuangzhou 510301China Scripps Institution of Oceanography University of CaliforniaSan DiegoLa JollaCalifornia 92093USA

This study investigates the activity of tropical cyclones(TCs)in the Bay of Bengal(BOB)from 1979 to 2018 to discover the mechanism affecting the contribution rate to the meridional moisture budget anomaly(MMBA)over the southern boundary of the Tibetan Plateau(SBTP).May and October–December are the bimodal phases of BOB TC frequency,which decreases month by month from October to December and is relatively low in ***,the contribution rate to the MMBA is the highest in *** seasonal variation in the meridional position of the westerlies is the key factor affecting the contribution *** relatively southern(northern)position of the westerlies in November and December(May)results in a lower(higher)contribution rate to the *** mechanism is confirmed by the momentum *** water vapor enters the westerlies near the trough line,the resultant meridional acceleration is directed *** follows that the farther north the trough is,and the farther north the water vapor can be *** water vapor enters the westerlies from the area near the ridge line,for Type-T(Type-R)TCs,water vapor enters the westerlies downstream of the trough(ridge).Consequently,the direction of the resultant meridional acceleration is directed south and the resultant zonal acceleration is directed east(west),which is not conducive to the northward transport of water *** is especially the case if the trough or ridge is relatively south,as the water vapor may not cross the SBTP.

关键词： tropical cyclone Tibetan Plateau Bay of Bengal moisture budget weste

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Design of an on‑chip wavelength conversion device assisted by an erbium‑ytterbium co‑doped waveguide amplifier

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Frontiers of Optoelectronics 2024年第2期17卷 51-60页

作者： Chen zhou Xiwen He Mingyue Xiao Deyue Ma Weibiao Chen Zhiping zhou School of Physical Sciences University of Science and Technology of ChinaHefei 230026China Aerospace Laser Technology and System Department Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Hangzhou Aijie Optoelectronic Technology Co.Ltd. Hangzhou 311400China

In current documented studies,it has been observed that wavelength converters utilizing AlGaAsOI waveguides exhibit suboptimal on-chip wavelength conversion efficiency from the C-band to the 2μm band,generally falling below−20.0 *** address this issue,we present a novel wavelength conversion device assisted by a waveguide amplifier,incorporating both AlGaAs wavelength converter and erbium-ytterbium co-doped waveguide amplifier,thereby achieving a notable conversion efficiency exceeding 0 *** noteworthy enhancement in efficiency can be attributed to the specific dispersion design of the AlGaAs wavelength converter,which enables an upsurge in conversion efficiency to−15.54 dB under 100 mW of pump ***,the integration of an erbium-ytterbium co-doped waveguide amplifier facilitates a loss compensation of over 15 *** the use of external optical amplifiers,this device enables efficient and high-bandwidth wavelength conversion,showing promising applications in various fields,such as optical communication,sensing,imaging,and beyond.

关键词： Silicon-based optoelectronics Wavelength conversion Waveguide amplifier 2μm band

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Learnware:small models do big

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Science China(Information Sciences) 2024年第1期67卷 39-50页

作者： Zhi-Hua zhou Zhi-Hao TAN National Key Laboratory for Novel Software Technology Nanjing University

There are complaints about current machine learning techniques such as the requirement of a huge amount of training data and proficient training skills,the difficulty of continual learning,the risk of catastrophic forgetting,and the leaking of data privacy/*** research efforts have been focusing on one of those concerned issues separately,paying less attention to the fact that most issues are entangled in *** prevailing big model paradigm,which has achieved impressive results in natural language processing and computer vision applications,has not yet addressed those issues,whereas becoming a serious source of carbon *** article offers an overview of the learnware paradigm,which attempts to enable users not to need to build machine learning models from scratch,with the hope of reusing small models to do things even beyond their original purposes,where the key ingredient is the specification which enables a trained model to be adequately identified to reuse according to the requirement of future users who know nothing about the model in advance.

关键词： artificial intelligence machine learning learnware

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Dynamics modeling and electromechanical coupling characteristics analysis of cage induction motors

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Science China(Technological Sciences) 2024年第3期67卷 709-724页

作者： zhou ZiWei CHEN ZaiGang ZHAI WanMing State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

Induction motors, as typical electromechanical energy conversion devices, have received limited attention in previous studies on electromechanical coupling vibrations, precise modeling, and the use of electromechanical coupling effects for fault diagnosis and condition assessment in motor drive systems. This study proposes a comprehensive model of cage induction motors that integrates the multiple coupled circuit model with a rotor-bearing dynamics model. The model accounts for the linear increase in the magnetomotive force across the slot and incorporates the skidding characteristics of bearings in the rotor-bearing system. By calculating the time-varying mutual inductance parameters based on the air-gap distribution in the vibration environment, the electromechanical coupling vibration of the cage motor is investigated. Furthermore, this study examines the electromechanical coupling vibration characteristics influenced by various factors, including bearing clearances, radial loads, and the vertical excitation frequencies of the stators. The results show that the proposed model improves the excitation inputs for the electrical and mechanical systems of the motor compared with conventional models. Increased bearing clearance and radial load affect the current and torque similarly but have opposite effects on the slip ratio. This study provides a deeper understanding of electromechanical coupling mechanisms and facilitates the use of such phenomena for fault diagnosis and condition assessment in motor-driven systems.

关键词： cage induction motors rotor-bearing dynamics mutual inductance electromechanical testing current signal analysis

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Molecular mechanism of Xuebijing in treating pyogenic liver abscess complicated with sepsis

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World Journal of Emergency Medicine 2024年第1期15卷 35-40页

作者： Wei zhou Maiying Fan Xiang Li Fang Yu En zhou Xiaotong Han Department of Emergency Medicine the First Affi liated Hospital of Hunan Normal University/Hunan Provincial People’s HospitalChangsha 410005China Department of Otolaryngology-head and Neck Surgery the First Affi liated Hospital of Hunan Normal University/Hunan Provincial People’s HospitalChangsha 410005China

BACKGROUND:Xuebijing(XBJ)can alleviate the inflammatory response,improve organ function,and shorten the intensive care unit(ICU)stay in patients with pyogenic liver abscess(PLA)complicated with sepsis,but the molecular mechanisms have not been *** study aimed to explore the molecular mechanism of XBJ in treating PLA complicated with sepsis using a network pharmacology ***:The active ingredients and targets of XBJ were retrieved from the ETCM *** targets related to PLA and sepsis were retrieved from the GeneCards,PharmGKB,DisGeNet,Online Mendelian Inheritance in Man(OMIM),Therapeutic Targets Database(TTD),and DrugBank *** targets of PLA complicated with sepsis were mapped to the targets of XBJ to identify potential treatment ***-protein interaction networks were analyzed using the STRING *** treatment targets were imported into the Metascape platform for Gene Ontology(GO)functional enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment *** docking was performed to validate the interactions between active ingredients and core ***:XBJ was found to have 54 potential treatment targets for PLA complicated with ***-1β(IL-1β),interleukin-6(IL-6),and tumor necrosis factor(TNF)were identifi ed as core *** enrichment analysis revealed important pathways,including the interleukin-17(IL-17)signaling pathway,the TNF signaling pathway,the nuclear factor-kappa B(NF-κB)signaling pathway,and the Toll-like receptor(TLR)signaling *** docking experiments indicated stable binding between XBJ active ingredients and core ***:XBJ may exert therapeutic eff ects on PLA complicated with sepsis by modulating signaling pathways,such as the IL-17,TNF,NF-κB,and TLR pathways,and targeting IL-1β,IL-6,and TNF.

关键词： Xuebijing injection Pyogenic liver abscess Sepsis

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