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Characterizing leaf-deposited particles: Single-particle mass spectral analysis and comparison with naturally fallen particles

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Environmental Science and Ecotechnology 2024年第5期21卷 318-328页

作者： Dele Chen Hua-yun Xiao Ningxiao sun Jingli Yan Shan Yin School of Agriculture and Biology Shanghai Jiao Tong University800 Dongchuan Rd.Shanghai 200240China Shanghai Yangtze River Delta Eco-Environmental Change and Management Observation and Research Station Ministry of Science and TechnologyMinistry of Education800 Dongchuan Rd.Shanghai 200240China Shanghai Urban Forest Ecosystem Research Station National Forestry and Grassland Administration800 Dongchuan Rd.Shanghai 200240China

The size and composition of particulate matter(PM)are pivotal in determining its adverse health *** is important to understand PM's retention by plants to facilitate its atmospheric ***,the distinctions between the size and composition of naturally fallen PM(NFPM)and leaf-deposited PM(LDPM)are not *** we utilize a single-particle aerosol mass spectrometer,coupled with a PM resuspension chamber,to analyze these *** find that LDPM particles are 6.8 e97.3%larger than *** a neural network algorithm based on adaptive resonance theory,we have identified distinct compositional profiles:NFPM predominantly consists of organic carbon(OC;31.2%)and potassium-rich components(19.1%),whereas LDPM are largely composed of crustal species(53.9e60.6%).Interestingly,coniferous species retain higher OC content(11.5e13.7%)compared to broadleaved species(0.5e1.2%),while the levoglucosan content exhibit an opposite *** study highlights the active role of tree leaves in modifying PM composition beyond mere passive capture,advocating for a strategic approach to species selection in urban greening initiatives to enhance PM *** insights provide guidance for urban planners and environmentalists in implementing nature-based solutions to improve urban air quality.

关键词： Particulate matter Dry deposition Phytoremediation Size distribution Chemical composition Source apportionment

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Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

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Journal of Energy Chemistry 2024年第1期88卷 1-9,I0001页

作者： Inhyeok Cho Jiwon yun Boseok Seong Junseok Kim sun Hee Choi Ho-Il Ji Sihyuk Choi Department of Mechanical Engineering Kumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Department of Aeronautics Mechanical and Electronic Convergence EngineeringKumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Center for Energy Materials Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Center for Hydrogen and Fuel Cell Research Clean Technology Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Department of Energy and Environmental Engineering University of Science and TechnologySeoul 02792Republic of Korea Nanomaterials Science and Engineering Korea University of Science and Technology(UST)KIST CampusSeoul 02792Republic of Korea

PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

关键词： Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy

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Hypoxia-induced nuclear localization of ubiquinol-cytochrome-c reductase complex assembly factor 3(UQCC3)in hepatocellular carcinoma

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Signal Transduction and Targeted Therapy 2024年第8期9卷 3173-3175页

作者： yun Yang Yinhao Wei Yiying sun Yong Zhou Hanshuo Yang Department of Biotherapy Cancer Center and State Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengdu 610041China Department of Gastrointestinal Surgery West China HospitalSichuan UniversityChengdu 610041China

Dear Editor,The mitochondrion plays crucial roles in cellular energy generation and signaling *** studies have shown that nuclear-encoded mitochondrial proteins translocate into the nucleus to regulate cell function a... 详细信息

关键词： hepatocellular retrograde communicate

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Rethinking Global Context in Crowd Counting

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Machine Intelligence Research 2024年第4期21卷 640-651页

作者： Guolei sun yun Liu Thomas Probst Danda Pani Paudel Nikola Popovic Luc Van Gool Computer Vision Lab ETH ZürichZürich 8092Switzerland Institute for Infocomm Research A*STARSingapore 138632Singapore Magic Leap Zürich 8050Switzerland

This paper investigates the role of global context for crowd ***,a pure transformer is used to extract features with global information from overlapping image *** by classification,we add a context token to the input sequence,to facilitate information exchange with tokens corresponding to image patches throughout transformer *** to the fact that transformers do not explicitly model the tried-and-true channel-wise interactions,we propose a token-attention module(TAM)to recalibrate encoded features through channel-wise attention informed by the context *** that,it is adopted to predict the total person count of the image through regression-token module(RTM).Extensive experiments on various datasets,including ShanghaiTech,UCFQNRF,JHU-CROWD++and NWPU,demonstrate that the proposed context extraction techniques can significantly improve the performanceover the baselines.

关键词： Crowd counting vision transformer global context attention density map.

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Vision Transformers with Hierarchical Attention

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Machine Intelligence Research 2024年第4期21卷 670-683页

作者： yun Liu Yu-Huan Wu Guolei sun Le Zhang Ajad Chhatkuli Luc Van Gool Institute for Infocomm Research(I2R) A*STARSingapore 138632Singapore Institute of High Performance Computing(IHPC) A*STARSingapore 138632Singapore Computer Vision Lab ETH ZürichZürich 8092Switzerland School of Information and Communication Engineering University of Electronic Science and Technology of China(UESTC)Chengdu 611731China

This paper tackles the high computational/space complexity associated with multi-head self-attention(MHSA)in vanilla vision *** this end,we propose hierarchical MHSA(H-MHSA),a novel approach that computes self-attention in a hierarchical ***,we first divide the input image into patches as commonly done,and each patch is viewed as a ***,the proposed H-MHSA learns token relationships within local patches,serving as local relationship ***,the small patches are merged into larger ones,and H-MHSA models the global dependencies for the small number of the merged *** last,the local and global attentive features are aggregated to obtain features with powerful representation *** we only calculate attention for a limited number of tokens at each step,the computational load is reduced ***,H-MHSA can efficiently model global relationships among tokens without sacrificing fine-grained *** the H-MHSA module incorporated,we build a family of hierarchical-attention-based transformer networks,namely *** demonstrate the superiority of HAT-Net in scene understanding,we conduct extensive experiments on fundamental vision tasks,including image classification,semantic segmentation,object detection and instance ***,HAT-Net provides a new perspective for vision *** and pretrained models are available at https://***/yun-liu/HAT-Net.

关键词： Vision transformer hierarchical attention global attention local attention scene understanding.

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The Boundedness of the Pullback Attractor for a 2D Micropolar Fluid Flows

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Acta Mathematicae Applicatae Sinica 2024年

作者： Wen-long sun Chun-lin LAI yun-yun LIANG School of information and mathematics Yangtze University

The purpose of this work is to investigate the boundedness of the pullback attractors for the micropolar fluid flows in two-dimensional unbounded domains. Exactly, the H1-boundedness and H2-boundedness of the pullback attractors are established when the external force F (t, x) has different regularity with respect to time variable, respectively.

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Understanding the cooperative effects in the catalysis of homodimeric fluoroacetate dehalogenase

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Science China Chemistry 2024年第7期67卷 2382-2391页

作者： Ke-Wei Chen Jia-Nan Chen Jun Zhang Chao Wang Tian-Yu sun yun-Dong Wu Key Laboratory of Computational Chemistry and Drug Design State Key Laboratory of Chemical OncogenomicSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China Institute of Chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China Changping Laboratory Beijing 102200China

Fluoroacetate dehalogenases(FAcD),a homodimeric enzyme,catalyzes the conversion of fluoroacetic acid to glycolic acid(GoA).It has been proved that the enzyme has a half-of-the-site ***,its catalytic(C)subunit converts the first substrate to a covalent intermediate;then,the non-catalytic(NC)subunit binds a second substrate and promotes the conversion of the intermediate in the C subunit into the final *** the release of the product,the C subunit becomes the NC subunit,and the previous NC subunit becomes the C *** elucidate the detailed mechanism behind this cooperative catalysis,we have conducted microsecond-scale MD simulations along the reaction *** simulations indicate that the substrate in the NC subunit induces W185 and Y141 adopting an open conformation in the C *** opening of W185(C)facilitates the entry of catalytic water,enhancing the catalytic activity for product formation,while the opening of Y141(C)creates an unfavorable environment for product binding,promoting its *** interaction network analysis reveals that the substrate in the NC subunit can induce conformational changes through a conserved water chain at the interface.

关键词： enzyme catalysis molecular dynamics cooperative effect pre-reaction state

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Nitrogen addition increased resistance of resident plant community to Solidago canadensis invasion by altering allelopathic effect

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Journal of Plant Ecology 2024年第2期17卷 110-121页

作者： Jing-Fang Cai kai sun Lin Li Si-Ha A Yi-Luan Shen Hong-Li Li School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China The Key Laboratory of EcologicalProtection in the Yellow River Basin of National Forestry and Grassland Administration Beijing Forestry UniversityBeijing 100083China

Allelopathy plays an important role in the interaction between invasive and resident *** nitrogen(N)deposition has become a global problem,but it is unclear whether N enrichment affects the interaction between invasive and resident plants by affecting their ***,we performed a greenhouse experiment in which the resident plant community was grown under two levels of invasion by ***(invasion *** invasion)and fully crossed with two levels of allelopathy(with or without adding activated carbon)and two levels of N addition(with or without).The resident plant communities were constructed with eight herbaceous species that often co-occur with *** results showed that both allelopathy of *** and the resident plants had obvious positive effects on their own *** addition had more obvious positive effects on the resident plants under invasion than those that were not ***,N addition also altered the allelopathy of resident ***,N addition improved the allelopathy of resident plants when they were invaded but decreased the allelopathy of resident plants when they grew *** nitrogen addition had no obvious effect on ***,it reduced the allelopathy of *** results suggest that N addition could improve the resistance of resident plants to invasion by improving the allelopathy of resident plants and reducing the allelopathy of *** fndings provide a scientifc basis to manage and control the *** invasion.

关键词： allelochemicals biological invasion nutrient input nitrogen addition resident plants Solidago canadensis

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磺酰化β-环糊精包合N,N′-二苯硫脲对钍的吸附研究

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原子能科学技术 2015年第1期49卷 19-25页

作者：张妮刘慧君孙允凯龙威彭彪南华大学化学化工学院湖南衡阳421001

通过取代反应合成了磺酰化β-环糊精(6-OTs-β-CD),并采用红外光谱与核磁共振对合成材料进行表征,验证了材料合成的可靠性;通过6-OTs-β-CD与N,N′-二苯硫脲以2∶1的摩尔比反应合成了包合物6-OTs-β-CD-N,N′-二苯硫脲,采用综合热分析... 详细信息

通过取代反应合成了磺酰化β-环糊精(6-OTs-β-CD),并采用红外光谱与核磁共振对合成材料进行表征,验证了材料合成的可靠性;通过6-OTs-β-CD与N,N′-二苯硫脲以2∶1的摩尔比反应合成了包合物6-OTs-β-CD-N,N′-二苯硫脲,采用综合热分析表征了包合物的热稳定性;用可见分光光度法分析了包合物及N,N′-二苯硫脲对钍离子的吸附行为。结果表明,室温下,相较于N,N′-二苯硫脲,6-OTs-β-CD-N,N′-二苯硫脲包合物对钍的吸附平衡时间大幅缩短。最佳吸附条件为pH=4、震荡反应10min、吸附剂加入量为0.025g,在此条件下吸附容量达27.46mg/g,吸附率达91.5%。

关键词：磺酰化β-环糊精包合物 N,N′-二苯硫脲钍吸附行为

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Geochemical and Isotopic Techniques Constraints on the Origin,Evolution,and Residence Time of Low-enthalpy Geothermal Water in Western Wugongshan,SE China

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Acta Geologica Sinica(English Edition) 2024年第3期98卷 801-818页

作者： WANG Luyao LIU kai MA Yan ZHANG Yaoyao TONG Jue JIA Wuhui ZHANG Shouchuan sun Junliang Chinese Academy of Geological Sciences Beijing 100037China School of Water Resources and Environment China University of Geoscience(Beijing)Beijing 100083China The Fourth Geological Brigade of Jiangxi Geological Bureau PingxiangJiangxi 337000China

Geothermal resources are increasingly gaining attention as a competitive,clean energy source to address the energy crisis and mitigate climate *** Wugongshan area,situated in the southeast coast geothermal belt of China,is a typical geothermal anomaly and contains abundant medium-and low-temperature geothermal *** study employed hydrogeochemical and isotopic techniques to explore the cyclic evolution of geothermal water in the western Wugongshan region,encompassing the recharge origin,water-rock interaction mechanisms,and residence *** results show that the geothermal water in the western region of Wugongshan is weakly alkaline,with low enthalpy and mineralization *** hydrochemistry of geothermal waters is dominated by Na-HCO_(3)and Na-SO_(4),while the hydrochemistry types of cold springs are all Na-HCO_(3).The hydrochemistry types of surface waters and rain waters are NaHCO_(3)or Ca-HCO_(3).The δD and δ^(18)O values reveal that the geothermal waters are recharged by atmospheric precipitation at an altitude between 550.0 and 1218.6 *** ratios of maj or solutes and isotopic compositions of^(87)Sr/^(86)Sr underscore the significant role of silicate weathering,dissolution,and cation exchange in controlling geothermal water ***,geothermal waters experienced varying degrees of mixing with cold water during their ***δ^(13)C values suggest that the primary sources of carbon in the geothermal waters were biogenic and ***δ^(34)S value suggests that the sulfates in geothermal water originate from sulfide minerals in the surrounding *** dating using 3H and^(14)C isotopes suggests that geothermal waters have a residence time exceeding 1 kaBP and undergo a long-distance cycling process.

关键词： geothermal water hydrochemistry isotope residence time Wugongshan area

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