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Journal of Environmental Sciences 2024年第4期138卷 266-276页

作者： Xu Liu xun wang Dingyong wang College of Resources and Environment Southwest UniversityChongqing 400715China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury(Hg)trends,but with the large knowledge gaps in the reliability.In this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at Mt.Jinyun in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric Hg.Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles.The Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg.We found a distinct age effect that the tree ring of young trees had the higher Hg concentration.Besides,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings.The modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in Chongqing.We finally suggest that in further Hg dendrochemistry,better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

关键词： Masson pine Tree-ring mercury Radial translocation Tree age effect

A Structural Measurement of the Valuation Effect of China's External Assets:Method and Application

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China & World Economy 2024年第2期32卷 97-124页

作者： Guowei Cai Xiaowei Chen xun wang Lingnan College Sun Yat-sen UniversityChina China Center for Economic Research National School of DevelopmentPeking UniversityChina

Existing research on the measurement of the valuation effect mainly follows the residual method proposed by Lane and Milesi-Ferretti(2001).This cannot be used to perform structural decomposition.We propose an aggregation approach rather than the residual method to measure structurally the investment flow and valuation effect of China's external assets.The results indicate that the valuation effect of China's external assets has been highly volatile and it was negative during the pandemic period.The structural decomposition shows that portfolio investment and direct investment made the main contributions to the valuation effect.The impact of exchange rates on the valuation effect has generally been higher than that of asset price in terms of direct investment and total external assets but the opposite has been true for portfolio investment.China's outward investments are currently more inclined to Asian countries and a few European countries but inflows to China still mainly come from developed countries.

关键词： external asset investment direction structural measurement valuation effect

Versatile Organogels of Aluminum Oxide Subnanosheets for Locking Solvents and Adhesion

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Precision Chemistry

Precision Chemistry 2024年第1期2卷 21-27页

作者： Wanyue Ouyang xun wang Key Lab of Organic Optoelectronics and Molecular Engineering Department of ChemistryTsinghua UniversityBeijing 100084China

Herein,we present a facile strategy to prepare versatile aluminum oxide subnanometer nanosheets with oleic acid and stearic acid ligands(OA-Al SNSs and SA-Al SNSs,respectively).The size effect endows subnanosheets with abundant acting sites,remarkable intermolecular interactions,and unique polymer-like properties,including flexibility,viscoelasticity,and sol-gel transitions,which is quite different from traditional inorganic materials.Consequently,subnanosheets could form freestanding organogels and OA-Al SNSs exhibit satisfying semisolidification of various solvents,making it an intriguing candidate for the safe storage and transportation of solvents.Furthermore,SA-Al SNSs exhibit excellent adhesive properties of high strength on diverse substrates,and it is easy to erase it without any damage,demonstrating the promising prospects in practical applications.

关键词： subnanometer nanomaterials self-assembly polymer-analogue organogel adhesive

Modified electronic structure and enhanced hydroxyl adsorption make quaternary Pt-based nanosheets efficient anode electrocatalysts for formic acid-/alcohol-air fuel cells

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Journal of Energy Chemistry 2024年第5期92卷 142-150页

作者： Fengling Zhao Qiang Yuan Siyang Nie Liang Wu xun wang State-Local Joint Laboratory for Comprehensive Utilization of Biomass Center for R&D of Fine ChemicalsCollege of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025GuizhouChina Key Lab of Organic Optoelectronics&Molecular Engineering Tsinghua UniversityBeijing 100084China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Surface/interface engineering of a multimetallic nanostructure with diverse electrocatalytic properties for direct liquid fuel cells is desirable yet challenging.Herein,using visible light,a class of quaternary Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)ultrathin nanosheets is fabricated and used as high-performance anode electrocatalysts for formic acid-/alcohol-air fuel cells.The modified electronic structure of Pt,enhanced hydroxyl adsorption,and abundant exterior defects afford Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C high intrinsic anodic electrocatalytic activity to boost the power densities of direct formic acid-/methanol-/ethanol-/ethylene glycol-/glycerol-air fuel cells,and the corresponding peak power density of Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C is respectively 129.7,142.3,105.4,124.3,and 128.0 mW cm^(-2),considerably outperforming Pt/C.Operando in situ Fourier transform infrared reflection spectroscopy reveals that formic acid oxidation on Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C occurs via a CO_(2)-free direct pathway.Density functional theory calculations show that the presence of Ag,Bi,and Te in Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)suppresses CO^(*)formation while optimizing dehydrogenation steps and synergistic effect and modified Pt effectively enhance H_(2)O dissociation to improve electrocatalytic performance.This synthesis strategy can be extended to 43 other types of ultrathin multimetallic nanosheets(from ternary to octonary nanosheets),and efficiently capture precious metals(i.e.,Pd,Pt,Rh,Ru,Au,and Ag)from different water sources.

关键词： Pt-based nanosheets Modifiedelectronic structure Enhanced hydroxyl adsorption Formicacidand alcohol oxidation Direct liquid fuel cells

Real-time identification of multiple nanoclusters with a protein nanopore in single-cluster level

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Nano Research 2024年第1期17卷 262-269页

作者： Ling Zhang Peilei He Huang Chen Qingda Liu Libo Li xun wang Jinghong Li Department of Chemistry Center for BioAnalytical ChemistryKey Laboratory of Bioorganic Phosphorus Chemistry&Chemical BiologyTsinghua UniversityBeijing 100084China School of Chemistry and Chemical Engineering Guangdong Prov Key Lab Green Chem Prod TechnolSouth China University of TechnologyGuangzhou 510640China New Cornerstone Science Laboratory Shenzhen 518054China Beijing Institute of Life Science and Technology Beijing 102206China Center for BioAnalytical Chemistry Hefei National Laboratory of Physical Science at MicroscaleUniversity of Science and Technology of ChinaHefei 230026China

It is important and challenging to analyze nanocluster structure with atomic precision.Herein,α-hemolysin nanopore was used to identify nanoclusters at the single molecule level by providing two-dimensional(2D)dwell time–current blockage spectra and translocation event frequency which sensitively depended on their structures.Nanoclusters such as Anderson,Keggin,Dawson,and a few lacunary Dawson polyoxometalates with very similar structures,even with only a two-atom difference,could be discriminated.This nanopore device could simultaneously measure multiple nanoclusters in a mixture qualitatively and quantitatively.Furthermore,molecular dynamics(MD)simulations provided microscopic understandings of the nanocluster translocation dynamics and yielded 2D dwell time–current blockage spectra in close agreement with experiments.The nanopore platform provides a novel powerful tool for nanocluster characterization.

关键词： nanopore single-molecule nanocluster polyoxometalates real-time detection

Control of GaN inverted pyramids growth on c-plane patterned sapphire substrates

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Journal of Semiconductors 2024年第6期45卷 92-96页

作者： Luming Yu xun wang Zhibiao Hao Yi Luo Changzheng Sun Bing Xiong Yanjun Han Jian wang Hongtao Li Lin Gan Lai wang Beijing National Research Center for Information Science and Technology Department of Electronic EngineeringTsinghua UniversityBei-jing 100084China Center for Flexible Electronics Technology Tsinghua UniversityBeijing 100084China

Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff constructions.The competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted pyramids.On the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.

关键词： inverted pyramids GaN MOVPE crystal growth competition model

Exploring the vital role of microglial membrane receptors in Alzheimer’s disease pathogenesis: a comprehensive review

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BIOCELL 2024年第7期48卷 1011-1022页

作者： JUN-FENG ZHAO YI-RAN JIANG TIAN-LIN GUO YONG-QING JIAO xun wang Department of Neurointervention Center Dalian No.3 People’s HospitalDalian Medical UniversityDalianChina Department of Clinical Medicine China Medical UniversityShenyangChina

Neurodegenerative diseases constitute a broad category of diseases caused by the degeneration of the neurons.They are mainly manifested by the gradual loss of neuron structure and function and eventually can cause death or loss of neurons.As the global population ages rapidly,increased people are being diagnosed with neurodegenerative diseases.It has been established that the onset of Alzheimer’s disease(AD)is closely linked with increasing age and its major pathological features include amyloid-beta plaques(Aβ),Tau hyperphosphorylation,Neuroﬁbrillary tangles(NFTs),neuronal death as well as synaptic loss.The involvement of microglia is crucial in the pathogenesis and progression of AD and exhibits a dual role.For instance,in the early stage of AD,microglia surface membrane proteins or receptors can participate in immunophagocytosis,and anti-inﬂammatory functions and act as a physical barrier after recognizing various ligands such as Aβand NFTs.However,in the later stage of the disease,membrane receptors on the surface of microglia can cause its activation to release a substantial quantity of pro-inﬂammatory factors.Which can amplify the neuroinﬂammatory response.The rapid decline of normal immune phagocytosis can result in the continuous accumulation of abnormal proteins,leading to neuronal dysfunction and destruction of the formed physical barrier as well as the neurovascular microenvironment.It can also increase the transformation of microglia from anti-inﬂammatory phenotype M2 to pro-inﬂammatory phenotype M1,induce severe neuronal injury or apoptosis,and aggravate the progression of AD.Due to few articles have focused on the AD-related membrane protein receptors on microglia,thus in this paper,we have reviewed several representative microglial membrane proteins or receptors about their speciﬁc roles and functions implicated in AD,and expect that there will be more in-depth research and scientiﬁc research results in the treatment of AD by targeted regulation of microglia membrane protein receptors in the future

关键词： Neurodegeneration Glial cell Receptor Alzheimer’s disease

Microsnoop: A generalist tool for microscopy image representation

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The Innovation 2024年第1期5卷 109-117页

作者： Dejin xun Rui wang Xingcai Zhang Yi wang Pharmaceutical Informatics Institute College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China State Key Lab of Computer-Aided Design&Computer Graphics Zhejiang UniversityHangzhou 310058China John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMA 02138USA Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University Hangzhou 310018China National Key Laboratory of Chinese Medicine Modernization Innovation Center of Yangtze River DeltaZhejiang UniversityJiaxing 314100China

Accurate profiling of microscopy images from small scale to high throughput is an essential procedure in basic and applied biological research.Here,we present Microsnoop,a novel deep learning–based representation tool trained on large-scale microscopy images using masked self-supervised learning.Microsnoop can process various complex and heterogeneous images,and we classified images into three categories:single-cell,full-field,and batch-experiment images.Our benchmark study on 10 high-quality evaluation datasets,containing over 2,230,000 images,demonstrated Microsnoop’s robust and state-ofthe-art microscopy image representation ability,surpassing existing generalist and even several custom algorithms.Microsnoop can be integrated with other pipelines to perform tasks such as superresolution histopathology image and multimodal analysis.Furthermore,Microsnoop can be adapted to various hardware and can be easily deployed on local or cloud computing platforms.We will regularly retrain and reevaluate the model using communitycontributed data to consistently improve Microsnoop.

关键词： hardware image representation

A novel evasion guidance for hypersonic morphing vehicle via intelligent maneuver strategy

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Chinese Journal of Aeronautics 2024年第5期37卷 441-461页

作者： xun LI Xiaogang wang Hongyu ZHOU Yu LI Department of Aerodynamics Harbin Institute of TechnologyHarbin 150001China Beijing Aerospace Technology Institute Beijing 100074China

This paper presents a novel evasion guidance law for hypersonic morphing vehicles,focusing on determining the optimized wing's unfolded angle to promote maneuverability based on an intelligent algorithm.First,the pursuit-evasion problem is modeled as a Markov decision process.And the agent's action consists of maneuver overload and the unfolded angle of wings,which is different from the conventional evasion guidance designed for fixed-shape vehicles.The reward function is formulated to ensure that the miss distances satisfy the prescribed bounds while minimizing energy consumption.Then,to maximize the expected cumulative reward,a residual learning method is proposed based on proximal policy optimization,which integrates the optimal evasion for linear cases as the baseline and trains to optimize the performance for nonlinear engagement with multiple pursuers.Therefore,offline training guarantees improvement of the constructed evasion guidance law over conventional ones.Ultimately,the guidance law for online implementation includes only analytical calculations.It maps from the confrontation state to the expected angle of attack and the unfolded angle while retaining high computational efficiency.Simulations show that the proposed evasion guidance law can utilize the change of unfolded angle to extend the maximum overload capability.And it surpasses conventional maneuver strategies by ensuring better evasion efficacy and higher energy efficiency.

关键词： Hypersonic vehicles Variable-sweep wings Evasion guidance Reinforcement learning Pursuit-evasion problem

Distributed Economic MPC for Synergetic Regulation of the Voltage of an Island DC Micro-Grid

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 734-745页

作者： Yi Zheng Yanye wang xun Meng Shaoyuan Li Hao Chen IEEE the Department of Automation Shanghai Jiao Tong UniversityShanghai 200240 the Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Haixi Institutes Chinese Academy of SciencesJinjiang 362216China

In this paper,distributed model predictive control(DMPC) for island DC micro-grids(MG) with wind/photovoltaic(PV)/battery power is proposed,which coordinates all distributed generations(DG) to stabilize the bus voltage together with the insurance of having computational efficiency under a real-time requirement.Based on the feedback of the bus voltage,the deviation of the current is dispatched to each DG according to cost over the prediction horizon.Moreover,to avoid the excessive fluctuation of the battery power,both the discharge-charge switching times and costs are considered in the model predictive control(MPC) optimization problems.A Lyapunov constraint with a time-varying steady-state is designed in each local MPC to guarantee the stabilization of the entire system.The voltage stabilization of the MG is achieved by this strategy with the cooperation of DGs.The numeric results of applying the proposed method to a MG of the Shanghai Power Supply Company shows the effectiveness of the distributed economic MPC.

关键词： Distributed model predictive control(DMPC) Lyapunovbased model predictive control micro-grid(MG) voltage control