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The low-latitude sodium layer:comparative data from lidar observations at Hainan,China and São Paulo,Brazil

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Earth and Planetary Physics 2025年第1期9卷 39-53页

作者： Fang Wu Jing Jiao GuoTao Yang LiFang Du ZhengKuan Liu HaoRan Zheng JiXin Guo ShaoHua Gong YaJun Zhu State Key Laboratory of Space weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Hainan National Field Science Observation and research Observatory for Space weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China China-Brazil Joint Laboratory for Space weather NSSC/INPESão Josédos Campos 12227-010Brazil School of Physics and Electronics Engineering Hainan Normal UniversityHaikou 571158China

Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude *** sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s *** paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the *** low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in ***,maximal Na density over Brazil is greater than that over *** variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before *** variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain *** suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.

关键词： metallic sodium layer seasonal variation nocturnal variation lidar

Deep reinforcement learning based integrated evasion and impact hierarchical intelligent policy of exo-atmospheric vehicles

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Chinese Journal of Aeronautics 2025年第1期38卷 409-426页

作者： Leliang REN Weilin GUO Yong XIAN Zhenyu LIU Daqiao ZHANG Shaopeng LI Xi’an research Institute of high Technology Xi’an 710025China China Xi’an Satellite Control center Xi’an710043China Department of Automation Tsinghua UniversityBeijing 100084China

Exo-atmospheric vehicles are constrained by limited maneuverability,which leads to the contradiction between evasive maneuver and precision *** address the problem of Integrated Evasion and impact(IEI)decision under multi-constraint conditions,a hierarchical intelligent decision-making method based on Deep Reinforcement Learning(DRL)was ***,an intelligent decision-making framework of“DRL evasion decision”+“impact prediction guidance decision”was established:it takes the impact point deviation correction ability as the constraint and the maximum miss distance as the objective,and effectively solves the problem of poor decisionmaking effect caused by the large IEI decision ***,to solve the sparse reward problem faced by evasion decision-making,a hierarchical decision-making method consisting of maneuver timing decision and maneuver duration decision was proposed,and the corresponding Markov Decision Process(MDP)was designed.A detailed simulation experiment was designed to analyze the advantages and computational complexity of the proposed *** results show that the proposed model has good performance and low computational resource *** minimum miss distance is 21.3 m under the condition of guaranteeing the impact point accuracy,and the single decision-making time is 4.086 ms on an STM32F407 single-chip microcomputer,which has engineering application value.

关键词： Exo-atmospheric vehicle Integrated evasion and impact Deep reinforcement learning Hierarchical intelligent policy Single-chip microcomputer Miss distance

Modification of Maxwell model for conductivity prediction of carbon nanotubes-filled polymer composites with tunneling effect

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 25-36页

作者： Jue ZHU Longyuan LI Ningtao ZHU Zhejiang Provincial Engineering research center for the Safety of Pressure Vessel and Pipeline Key Laboratory of impact and Safety Engineering (Ningbo University) Ministry of Education School of Engineering Computing and Mathematics University of Plymouth Xi'an Zhanshi Testing & Engineering Co.Ltd.

Carbon nanotubes(CNTs) have garnered great attention in recent years due to their outstanding electrical, thermal, and mechanical properties. The incorporation of small amounts of CNTs in polymers can substantially improve the sensitivity of the polymer's electrical conductivity. This paper presents a modified Maxwell model to evaluate the electrical conductivity of CNTs-filled polymer composites by introducing a transition zone to account for the tunneling effect. In this modified Maxwell model, the CNTs-filled polymer composite is modeled as a three-phase composite, consisting of a matrix(polymer), inclusions(CNTs), and a transition zone(tunneling zone). The effective electrical conductivity(EEC) of the composite is calculated based on the volume fractions and electrical conductivities of the matrix, inclusions, and transition zone. The model's validity is confirmed through the use of available test data, which demonstrates its capability to accurately capture the nonlinear conductivity behavior observed in CNTs-polymer composites. This study offers valuable insights into the design of high-performance conductive polymer nanocomposites, and enhances the understanding of electrical conduction mechanisms in CNT-dispersed polymer composites.

关键词： carbon nanotube (CNT) composite electrical conductivity Maxwell model O242.2 O441.1 polymer tunneling

Enhancing weather predictions: Initial condition sensitivity and error dynamics in data assimilation

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Science China Earth Sciences 2025年第2期68卷 649-652页

作者： Weiwei FU Department of Atmospheric and Oceanic Sciences Fudan UniversityShanghai 200438China Key Laboratory of Polar Atmosphere-ocean-ice System for weather and Climate Ministry of EducationFudan UniversityShanghai 200438China IRDR International center of Excellence on Risk Interconnectivity and Governance on weather Fudan UniversityShanghai 200438China

Data Assimilation(DA) plays a crucial role in modern numerical forecasting(Kalnay, 2002). It has been demonstrated that incorporating real-time observational data into forecast models significantly enhances the accuracy of both shortterm weather forecasts(Bauer et al., 2015;Bannister, 2017)and long-term climate predictions(Karspeck et al., 2013;Mochizuki et al., 2016).

关键词： weather assimilation forecasting

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Revealing the Role of Hydrogen in highly Efficient Ag-Substituted CZTSSe Photovoltaic Devices:Photoelectric Properties Modulation and Defect Passivation

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Nano-Micro Letters 2025年第4期17卷 166-180页

作者： Xiaoyue Zhao Jingru Li Chenyang Hu Yafang Qi Zhengji Zhou Dongxing Kou Wenhui Zhou Shengjie Yuan Sixin Wu The Key Laboratory for Special Functional Materials of MOE School of Nanoscience and Materials EngineeringNational and Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologyCollaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004People’s Republic of China

The presence of SnZn-related defects in Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)absorber results in large irreversible energy loss and extra irreversible electron-hole non-radiative recombination,thus hindering the efficiency enhancement of CZTSSe *** the incorporation of Ag in CZTSSe can effectively suppress the SnZn-related defects and significantly improve the resulting cell performance,an excellent efficiency has not been achieved to date primarily owing to the poor electrical-conductivity and the low carrier density of the CZTSSe film induced by Ag ***,this study exquisitely devises an Ag/H co-doping strategy in CZTSSe absorber via Ag substitution programs followed by hydrogen-plasma treatment procedure to suppress SnZn defects for achieving efficient CZTSSe ***-depth investigation results demonstrate that the incorporation of H in Ag-based CZTSSe absorber is expected to improve the poor electrical-conductivity and the low carrier density caused by Ag ***,the C=O and O-H functional groups induced by hydrogen incorporation,serving as an electron donor,can interact with under-coordinated cations in CZTSSe material,effectively passivating the SnZn-related ***,the incorporation of an appropriate amount of Ag/H in CZTSSe mitigates carrier non-radiative recombination,prolongs minority carrier lifetime,and thus yields a champion efficiency of 14.74%,showing its promising application in kesterite-based CZTSSe devices.

关键词： CZTSSe Ag/H co-doping Photoelectric properties modulation Defect passivation Non-radiative recombination

Airborne Investigation of Riming:Cloud and Precipitation Microphysics within a Weak Convective System in North China

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Advances in Atmospheric Sciences 2025年第3期42卷 515-526页

作者： Xiangfeng HU Hao HUANG Shaoyu HOU Kun ZHAO Chuanfeng ZHAO Yinghui LU Jiefang YANG Rong ZHANG Delong ZHAO Weiguo LIU Dan ZHANG Haixia XIAO Key Laboratory of Radar Meteorology and State Key Laboratory of Severe weather China Meteorology AdministrationBeijing 100044China China Meteorological Administration Xiong'an Atmospheric Boundary Layer Key Laboratory Xiong'an New AreaHebei 071703China Hebei Provincial weather Modification center ShijiazhuangHebei 051430China School of Atmospheric Sciences Key Laboratory of Mesoscale Severe Weather/MOEand Frontiers Science Center for Critical Earth Material CyclingNanjing UniversityJiangsu 210023China Department of Atmospheric and Oceanic Sciences School of PhysicsPeking UniversityBeijing 100871China Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Cloud-Precipitation Physics and weather Modification Key Laboratory China Meteorology AdministrationBeijing 100044China Beijing weather Modification center Beijing 100089China Nanjing Joint Institute for Atmospheric Sciences NanjingJiangsu 210000China

The process of riming significantly impacts the microphysical characteristics of *** study uses aircraft and radar observation data in stratiform clouds with convection embedded that occurred in the central and southern regions of North China on 22 May *** microphysical structural characteristics and processes near the embedded convection core and in the stratiform cloud are analyzed *** attention is given to the effect of riming on the microphysical properties near the upper boundary of the melting layer and to the factors influencing riming *** collaborative observations reveal that the particle size distributions observed near the convection core and in the stratiform region are close,while the particle properties like habit and riming degree are quite *** the melting layer,larger plate-like ice particles and supercooled water droplets(D>50μm)are more abundant near the convective core,leading to higher collision efficiencies between ice particles and supercooled water *** fluctuation amplitudes of vertical airflow near the convective core also contribute to the increased riming activity and the formation of more heavily rimed particles,such as ***,in situ measurements from airborne probes also revealed that above the melting layer,the riming process involves two stages:the mass of snow crystals grows as supercooled droplets merge internally without changing size,followed by external freezing that significantly enlarges the crystals.

关键词： riming collision efficiency airflow fluctuation particle habit aircraft measurement

Electronic interactions between neighboring functionalized guest Sb single atoms and Pt clusters enhance CO tolerance

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Journal of Energy Chemistry 2025年第2期101卷 733-743页

作者： Wenkang Miao Ronghui Hao Lu Gan Wanyin Xu Zihan Wang Wenxin Lin Heguang Liu Yinchun Lyu Qianqian Li Jinyang Xi Anmin Nie Jinsong Wu Hongtao Wang Materials Genome Institute Shanghai University School of Materials Science and Engineering Zhejiang Sci-Tech University School of Materials Science and Engineering Xi'an University of Technology center for high Pressure Science State Key Laboratory of Metastable Materials Science and Technology Yanshan University Nanostructure research center Wuhan University of Technology center for X-mechanics Zhejiang University

Platinum-based（Pt） catalysts are notoriously susceptible to deactivation in industrial chemical processes due to carbon monoxide（CO） *** this poisoning deactivation of Pt-based catalysts while enhancing their catalytic activity,selectivity,and durability remains a major ***,we propose a strategy to enhance the CO tolerance of Pt clusters（Pt_n） by introducing neighboring functionalized guest single atoms（such as Fe,Co,Ni,Cu,Sb,and Bi）.Among them,antimony（Sb） single atoms（SAs） exhibit significant performance enhancement,achieving 99% CO selectivity and 33.6% CO2conversion at 450℃,Experimental results and density functional theory（DFT） calculations indicate the optimization arises from the electronic interaction between neighboring functionalized Sb SAs and Pt clusters,leading to optimal 5d electron redistribution in Pt clusters compared to other functionalized guest single *** redistribution of 5d electrons weaken both the σ donation and π backdonation interactions,resulting in a weakened bond strength with CO and enhancing catalyst activity and *** situ environmental transmission electron microscopy（ETEM） further demonstrates the exception thermal stability of the catalyst,even under H2at 700℃.Notably,the functionalized Sb SAs also improve CO tolerance in various heterogenous catalysts,including Co/CeO2,Ni/CeO2,Pt/Al2O3,and Pt/*** finding provides an effective approach to overcome the primary challenge of CO poisoning in Pt-based catalysts,making their broader applications in various industrial catalysts.

关键词： CO tolerance Electronic effect Functionalized guest single atoms In-situ TEM Pt cluster

Distinct Mechanisms Governing Two Types of Extreme Hourly Rainfall Rates in the Mountain Foothills of North China During the Passage of a Typhoon Remnant Vortex from 30 July to 1 August 2023

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Advances in Atmospheric Sciences 2025年第4期42卷 761-779页

作者： Rudi XIA Yuqing RUAN Jisong SUN Xudong LIANG Chong WU Feng LI Ju LI Jinfang YIN Xinghua BAO Mingxin LI Xiaoyu GAO State Key Laboratory of Severe weather Chinese Academy of Meteorological SciencesBeijing 100081China Collaborative Innovation center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China research center for Disastrous weather over Hengduan Mountains&Low-Latitude Plateau China Meteorological AdministrationKunming 650034China

This study investigates extreme rainfall episodes along the eastern foothills of the Taihang Mountains in North China from 30 July to 1 August *** focuses on two types of extreme hourly rainfall rates(HRRs),i.e.,the maximum regionalaverage HRR and site-observed HRR,which exhibited sequential development over southern,middle,and northern key *** rainfall extremes occurred in an environment where a high-pressure barrier over North China prevented the intrusion of cold air masses from the north while a northward-moving typhoon remnant vortex and its associated low-level jet(LLJ)transported warm and moist airflow from the *** distinct echo evolution modes and convection initiation mechanisms are identified for the two types of extreme *** maximum regional-average HRR occurred when the LLJ arrived to the east of the key regions,while the maximum site-observed HRR occurred when the warmer vortex center influenced the *** the northern key region as a representation,at the time of the maximum regional-average HRR,slantwise ascent of the airflow along a warm-frontal-like boundary released energy related to symmetrical instability,resulting in stratiform rainfall with weak convective *** transport of locally initiated convection over the eastern plain region,where the atmospheric stratification was more potentially unstable,also significantly *** the maximum site-observed HRR occurred,the terrain lifting of warm and moist southeast airflow led to intense convection over the mountain ***,the passage of the warm-core typhoon remnant vortex and interaction with Taihang Mountains determined the timing and location of extreme HRRs across the key regions.

关键词： extreme rainfall hourly rainfall rate mountain vortex mechanism

Quantum metrology with optimal control under an arbitrary non-Markovian bosonic environment

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Communications in Theoretical Physics 2025年第2期77卷 112-120页

作者： Likun Zhou Wen Yang Beijing Computational Science research center

Finding the optimal control is of importance to quantum metrology under a noisy *** this paper, we tackle the problem of finding the optimal control to enhance the performance of quantum metrology under an arbitrary non-Markovian bosonic environment. By introducing an equivalent pseudomode model, the non-Markovian dynamic evolution is reduced to a Lindblad master equation, which helps us to calculate the gradient of quantum Fisher information and perform the gradient ascent algorithm to find the optimal control. Our approach is accurate and circumvents the need for the Born–Markovian approximation. As an example, we consider the frequency estimation of a spin with pure dephasing under two types of non-Markovian environments. By maximizing the quantum Fisher information at a fixed evolution time, we obtain the optimal multi-axis control, which results in a notable enhancement in quantum metrology. The advantage of our method lies in its applicability to the arbitrary non-Markovian bosonic environment.

关键词： quantum metrology non-Markovian environment optimal control