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Water vapour multi-vortex structure under the interactions of typhoons and mid-low latitude systems during extreme precipitation in North China

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Advances in Climate Change Research 2023年第1期14卷 116-125页

作者： Jia-Hui TANG xiang-de xu Wen-Yue CAI Chun-Zhu WANG Nanjing University of Information Science&Technology Nanjing 210044China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China National Climate Center China Meteorological AdministrationBeijing 100081China Training Center China Meteorological AdministrationBeijing 100081China

With diverse atmospheric circulation and complex mechanisms,typhoon remote rainstorms(TRR)are closely related to a variety of mid-low latitude systems.The anomalous signatures in such processes can improve forecasting heavy rainfall associated with typhoons and fill the gaps in current physical conceptual models of TRR.Using the optimal typhoon path dataset,ground observation data,and the National Centres for Environmental Prediction(NCEP)reanalysis dataset,the impact of anomalous water vapour transport on excessive rainfall in North China is investigated.The vector empirical orthogonal function(VEOF)analysis is applied to typhoon precipitation events from 1970 to 2021,and three major modes are extracted to reflect the anomalous water vapour transport for typhoon precipitation.Mode 1 reflects a moisture circulation pattern in North China due to the coexistence of typhoons and remote and direct precipitation,with the highest probability of heavy precipitation.The differences in remote precipitation areas and intensities are attributed to the location of typhoons in the western North Pacific and the shifting of the subtropical high ridge.To characterise the water vapour transport circulation of TRR in North China,we proposed the‘multivortex’idea.The transmission of the multi-vortex ensures a continuous supply of TRR water vapour,and the enhancement of the multi-vortex is significantly linked to the enhancement of remote precipitation.Three extreme northern rainstorms,75·8 Henan,7·21 Beijing,and 7·20 Zhengzhou rainstorms,have anomalous multi-vortex water vapour convergence,similar to Mode 1.The mechanism of water vapour driven by multi-vortex in the three severe rainstorm events is more extreme than in usual TRR events in North China.The stronger Indian low vortex and relatively southerly subtropical highs can intensify the southwest branch of the double water vapour transport branch,whereas the strengthening of typhoons in the western North Pacific facilitates water vapour transport through the channel on the sou

关键词： Typhoon remote rainstorm Mid-low latitude circulation systems Interaction Multi-vortex

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Effects of Modified Inclusions and Precipitates Alloyed by Rare Earth Element on Corrosion and Impact Properties in Low Alloy Steel

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Acta Metallurgica Sinica(English Letters) 2022年第10期35卷 1719-1730页

作者： Xin-Tong Lian Long Chen Zeng-Wei Fan Teng-Shi Liu de-xiang xu Han Dong State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai200444China School of Materials Science and Engineering Shanghai UniversityShanghai200444China

This study has focused on the morphology and distribution of inclusions and precipitates modified by rare earth(RE)elements,which has a decisive influence on microstructure,corrosion properties and impact behaviors in Q355 low alloy steel.Characterized by the method of electrolytic extraction and ASPEX-scanning electron microscopy(ASPEX-SEM),small-sized spherical RE inclusions have been modified to replace elongated MnS and large-sized Al_(2)O_(3).Q355RE steel after RE alloying has lower corrosion rate and higher value ofα/γ,due to the formation of stable and dense rust layers.Q355RE steel also exhibits better resistance to fracture at low temperature,owing to the presence of RE modification to inclusions and its effects on reducing crack initiation and propagation.Nano-scale RE precipitates containing sulfur and phosphorus is observed along grain boundaries by transmission electron microscopy(TEM).The purification of grain boundaries by RE is beneficial to the improvement of corrosion and impact properties.

关键词： Rare earth element Inclusion Precipitate Q355 low alloy steel Corrosion resistance Impact toughness

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decomposition mechanisms of nuclear-grade cationic exchange resin by advanced oxidation processes:Statistical molecular fragmentation model and DFT calculations

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Journal of Environmental Sciences 2024年第1期135卷 433-448页

作者： xiang Meng Pierre Désesquelles Lejin xu department of Nuclear Engineering and Technology School of Energy and Power EngineeringHuazhong University of Science&TechnologyWuhan 430074China CNRS Laboratoire de Physique des Gaz et des PlasmasUniversitéParis-SaclayOrsay 91405France State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The treatment and disposal of radioactive waste are presently facing great challenges.Spent ion exchange resins have become a focus of attention due to their high production and serious environmental risks.In this paper,a simplified model of cationic exchange resin is proposed,and the degradation processes of cationic resin monomer initiated by hydroxyl radicals(·OH)are clarified by combining statistical molecular fragmentation(SMF)model and density functional theory(DFT)calculations.The prediction of active sites indicates that the S-O bonds and the C-S bond of the sulfonic group are more likely to react during the degradation.The meta-position of the sulfonic group on the benzene ring is the most active site,and the benzene ring without the sulfonic group has a certain reactivity.The C11-C14 and C17-C20 bonds,on the carbon skeleton,are the most easily broken.It is also found that dihydroxy addition and elimination reactions play a major role in the process of desulfonation,carbon skeleton cleavage and benzene ring separation.The decomposition mechanisms found through the combination of physical models and chemical calculations,provide theoretical guidance for the treatment of complex polycyclic aromatic hydrocarbons.

关键词： Cationic exchange resin Statistical molecular fragmentation model density functional theory Hydroxyl radical decomposition mechanism

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TP-PROFILE: Monitoring the Thermodynamic Structure of the Troposphere over the Third Pole

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Advances in Atmospheric Sciences 2024年第6期41卷 1264-1277页

作者： xuelong CHEN Yajing LIU Yaoming MA Weiqiang MA xiangde xu Xinghong CHENG Luhan LI Xin xu Binbin WANG Land-Atmosphere Interaction and its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan College of Atmospheric Science Lanzhou UniversityLanzhou 730000China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Disastrous Weather China Academy of Meteorological SciencesBeijing 100081China

Ground-based microwave radiometers(MWRs)operating in the K-and V-bands(20–60 GHz)can help us obtain temperature and humidity profiles in the troposphere.Aside from some soundings from local meteorological observatories,the tropospheric atmosphere over the Tibetan Plateau(TP)has never been continuously observed.As part of the Chinese Second Tibetan Plateau Scientific Expedition and Research Program(STEP),the Tibetan Plateau Atmospheric Profile(TPPROFILE)project aims to construct a comprehensive MWR troposphere observation network to study the synoptic processes and environmental changes on the TP.This initiative has collected three years of data from the MWR network.This paper introduces the data information,the data quality,and data downloading.Some applications of the data obtained from these MWRs were also demonstrated.Our comparisons of MWR against the nearest radiosonde observation demonstrate that the TP-PROFILE MWR system is adequate for monitoring the thermal and moisture variability of the troposphere over the TP.The continuous temperature and moisture profiles derived from the MWR data provide a unique perspective on the evolution of the thermodynamic structure associated with the heating of the TP.The TP-PROFILE project reveals that the low-temporal resolution instruments are prone to large uncertainties in their vapor estimation in the mountain valleys on the TP.

关键词： microwave radiometer thermodynamic structure vertical profile Tibetan Plateau

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Comparative evaluation of SPE methods for biotoxicity assessment of water and wastewater:Linkage between chemical extracting efficiency and biotoxicity outcome

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Journal of Environmental Sciences 2024年第8期142卷 33-42页

作者： Jiawei Zhou Shihao Wang Xiwei He Hongqiang Ren xu-xiang Zhang State Key Laboratory of Pollution Control and Resource Reuse School of EnvironmentNanjing UniversityNanjing 210023China

Biotoxicity assessment results of environmental waters largely depend on the sample extraction protocols that enrich pollutants to meet the effect-trigger thresholds of bioassays.However,more chemical mixture does not necessarily translate to higher combined biotoxicity.Thus,there is a need to establish the link between chemical extracting efficiency and biotoxicity outcome to standardize extraction methods for biotoxicity assessment of environmental waters.This study compares the performance of five different extraction phases in solid phase extraction(SPE),namely HLB,HLB+Coconut,C18 cartridge,C18 disk and Strata-X,and evaluated their chemical extracting efficiencies and biotoxicity outcomes.We quantitatively assessed cytotoxicity,acute toxicity,genotoxicity,estrogenic activity,and neurotoxicity of the extracts using in vitro bioassays and characterized the chemical extracting efficiencies of the SPE methods through chemical recoveries of 23 model compounds with different polarities and total organic carbon.Using Pareto ranking,we identified HLB+Coconut as the optimal SPE method,which exhibited the highest level of water sample biotoxicity and recovered the most chemicals in water samples.We found that the biotoxicity outcomes of the extracted water samples significantly and positively correlated with the chemical extracting efficiencies of the SPE methods.Moreover,we observed synchronous changing patterns in biotoxicity outcome and chemical extracting efficiencies in response to increasing sample volumes per cartridge(SVPC)during SPE.Our findings underscore that higher chemical extracting efficiency of SPE corresponds to higher biotoxicity outcome of environmental water samples,providing a scientific basis for standardization of SPE methods for adequate assessment of biotoxicities of environmental waters.

关键词： Biotoxicity Chemical recovery Solid phase extraction Surface water Wastewater

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Adversarial data splitting for domain generalization

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Science China(Information Sciences) 2024年第5期67卷 28-42页

作者： xiang GU Jian SUN Zongben xu School of Mathematics and Statistics Xi'an Jiaotong University

Domain generalization aims to learn a model that is generalizable to an unseen target domain,which is a fundamental and challenging task in machine learning for out-of-distribution generalization. This paper proposes a novel domain generalization approach that enforces the learned model to be able to generalize well over the train/val subset splitting of the training dataset. This idea is modeled herein as an adversarial data splitting framework, formulated as a min-max optimization problem inspired by the metalearning approach. The min-max optimization problem is solved by iteratively splitting the training dataset into the training and val subsets to maximize the domain shift measured by the objective function and updating the model parameters to enable the model to generalize well from the training subset to the val subset by minimizing the objective function. This adversarial training approach does not assume the known domain labels of the training data; instead, it automatically investigates the “hard” splitting of the train/val subsets to learn the generalizable model. Extensive experimental results using three benchmark datasets demonstrate the superiority of this approach. In addition, we derive a generalization error bound for the theoretical understanding of our proposed approach.

关键词： domain generalization adversarial learning data splitting meta-learning out of distribution

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Thermal fatigue and wear of compacted graphite iron brake discs with various thermomechanical properties

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China Foundry 2024年第3期21卷 248-256页

作者： Gui-quan Wang Zhuo xu Zhong-li Liu xiang Chen Yan-xiang Li School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

The increase in payload capacity of trucks has heightened the demand for cost-effective yet high performance brake discs.In this work,the thermal fatigue and wear of compacted graphite iron brake discs were investigated,aiming to provide an experimental foundation for achieving a balance between their thermal and mechanical properties.Compacted graphite iron brake discs with different tensile strengths,macrohardnesses,specific heat capacities and thermal diffusion coefficients were produced by changing the proportion and strength of ferrite.The peak temperature,pressure load and friction coefficient of compacted graphite iron brake discs were analyzed through inertia friction tests.The morphology of thermal cracks and 3D profiles of the worn surfaces were also discussed.It is found that the thermal fatigue of compacted graphite iron discs is determined by their thermal properties.A compacted graphite iron with the highest specific heat capacity and thermal diffusion coefficient exhibits optimal thermal fatigue resistance.Oxidization of the matrix at low temperatures significantly weakens the function of alloy strengthening in hindering the propagation of thermal cracks.despite the reduced hardness,increasing the ferrite proportion can mitigate wear loss resulting from low disc temperatures and the absence of abrasive wear.

关键词： compacted graphite iron brake disc thermomechanical properties thermal fatigue wear

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The role of proteasomes in tumorigenesis

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Genes & Diseases 2024年第4期11卷 155-169页

作者： xiangyi Zhou Ruqing xu Yue Wu Li Zhou Tingxiu xiang department of Oncology The First Affliated Hospital of Chongqing Medical UniversityChongqing 400016China Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment Chongqing University Cancer HospitalChongqing 400030China

Protein homeostasis is the basis of normal life activities,and the proteasomefamily plays an extremely important function in this process.The proteasome 2os is a concentric circle structure with twoαrings and twoβrings overlapped.The proteasome 2os can perform both ATP-dependent and non-ATP-dependent ubiquitination proteasome degradation by binding to various subunits(such as 19S,11S,and 200 PA),which is performed by its active subunitβ1,β2,andβ5.The proteasome can degrade misfolded,excess proteins tomaintain homeostasis.At the same time,it can be utilized by tumors to degrade over-proliferate and unwanted proteins to support their growth.Proteasomes can affect the development of tumors from several aspects including tumor signaling pathways such as NF-kB and p53,cell cycle,immune regulation,and drug resistance.Proteasome-encoding genes have been found to be overexpressed in a variety of tumors,providing a potential novel target for cancer therapy.In addition,proteasome inhibitors such as bortezomib,carfilzomib,and ixazomib have been put into clinical application as the first-line treatment of multiple myeloma.More and more studies have shown that it also has different therapeutic effects in other tumors such as hepatocellular carcinoma,non-small cell lung cancer,glioblastoma,and neuroblastoma.However,proteasome inhibitors are not much effective due to their tolerance and singleness in other tumors.Therefore,further studies on their mechanisms of action and drug interactions are needed to investigate their therapeutic potential.

关键词： Bortezomib Cancer therapy Immunoproteasome Multiplemyeloma Proteasome 20S Proteasome inhibitor Thymoproteasom

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Iron–doped bismuth oxybromides as visible-light-responsive Fenton catalysts for the degradation of atrazine in aqueous phases

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Journal of Environmental Sciences 2024年第3期137卷 321-332页

作者： Yong-Li Cai Yu-Hang xu Ji-Zun xiang Zhi-Qiang Zhang Qiu-xiang He Ya-Feng Li Jian Lü Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China State Key Laboratory of Photocatalysis on Energy and Environment Fuzhou UniversityFuzhou 350116China

Pesticides and its degradation products,being well–known residues in soil,have recently been detected in many water bodies as pollutants of emerging concerns,and thus there is a contemporary demand to develop viable and cost–effective techniques for the removal of related organic pollutants in aqueous phases.Herein,a visible-light-responsive Fenton system was constructed with iron–doped bismuth oxybromides(Fe–BiOBr)as the catalysts.Taking the advantage of sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion and optimized H_(2)O_(2)utilization,the optimal Fe–BiOBr–2 catalyst showed an excellent atrazine removal efficiency of 97.61%in 120 min,which is superior than the traditional homogeneous Fenton and the majority of heterogeneous processes documented in the literature.In this photo–Fenton system,hydroxyl(·OH)and superoxide(·O_(2)^(-))radicals were dominant active species contributed to the oxidative degradation of atrazine.Due to the production of various active radicals,five degradation pathways were proposed based on the identification of intermediates and degradation products.Overall,this work not only demonstrates a fundamental insight into creating highly efficient and atom economic photo-Fenton systems,but also provides a complementary strategy for the treatment of organic pollutants in water.

关键词： Bismuth oxybromide Photo–Fenton Atrazine Catalytic degradation

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Post-acute ischemic stroke hyperglycemia aggravates destruction of the blood-brain barrier

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Neural Regeneration Research 2024年第6期19卷 1344-1350页

作者： Tianqi xu Jianhong Yang Yao xu Xiaofeng Wang xiang Gao Jie Sun Chenhui Zhou Yi Huang department of Neurology The First Affiliated Hospital of Ningbo University department of General Surgery The First Affiliated Hospital of Ningbo University department of Neurosurgery The First Affiliated Hospital of Ningbo University Key Laboratory of Precision Medicine for Atherosclerotic Diseases of Zhejiang Province

Post-acute ischemic stroke hyperglycemia increases the risk of hemorrhagic transformation, which is associated with blood-brain barrier disruption. Brain microvascular endothelial cells are a major component of the blood-brain barrier. Intercellular mitochondrial transfer has emerged as a novel paradigm for repairing cells with mitochondrial dysfunction. In this study, we first investigated whether mitochondrial transfer exists between brain microvascular endothelial cells, and then investigated the effects of post-acute ischemic stroke hyperglycemia on mitochondrial transfer between brain microvascular endothelial cells. We found that healthy brain microvascular endothelial cells can transfer intact mitochondria to oxygen glucose deprivation-injured brain microvascular endothelial cells. However, post-oxygen glucose deprivation hyperglycemia hindered mitochondrial transfer and exacerbated mitochondrial dysfunction. We established an in vitro brain microvascular endothelial cell model of the blood-brain barrier. We found that post-acute ischemic stroke hyperglycemia reduced the overall energy metabolism levels of brain microvascular endothelial cells and increased permeability of the blood-brain barrier. In a clinical study, we retrospectively analyzed the relationship between post-acute ischemic stroke hyperglycemia and the severity of hemorrhagic transformation. We found that post-acute ischemic stroke hyperglycemia serves as an independent predictor of severe hemorrhagic transformation. These findings suggest that post-acute ischemic stroke hyperglycemia can aggravate disruption of the blood-brain barrier by inhibiting mitochondrial transfer.

关键词： acute ischemic stroke blood-brain barrier brain microvascular endothelial cells mitochondrial transfer stress hyperglycemia

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