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A storm-time ring current model(STRIM)

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Science China(Technological Sciences) 2024年第12期67卷 3890-3908页

作者： yu YiQun MA LongXing WEI ZiMing AN DePeng WU HaiJun lu hao yu CAO JinBin School of Space and Earth Sciences Beihang UniversityBeijing 100191China Key Laboratoryof SpaceEnvironment Monitoring and Information Processing Ministryof Industry and Information TechnologyBejing 100191China

The ring current,one of the most important current systems around the Earth,intensifies during geomagnetic storms and is believed to be the main reason for large-scale magnetic field perturbations in the geospace *** how the ring current builds up and evolves during geomagnetic storms is of great importance not only for advancing the knowledge of the Sun-Earth system but also for improving the modeling capability of predicting hazardous space weather *** on the national strategic needs in the space weather prediction,in this study,we establish a ring current model named storm time ring current model(STRIM).The STRIM comprehensively embraces key physical processes in association with ring current dynamics,including plasma source injections from the nightside plasmasheet and transport around the Earth,charge-exchange with neutral hydrogens,Coulomb collisions with thermal plasma,wave-particle interactions,field line curvature scattering,and precipitation loss down to the upper *** electric fields needed for particle motion can be optionally taken from empirical models or self-consistently calculated,while the magnetic field configuration is obtained from Tsyganenko 2005 *** results are verified against the published literature and validated with in-situ satellite or ground-based observations and are found to have the same high-level capability and fidelity as other well-known published *** also discuss future tasks of fostering the model's performance and potential applications.

关键词： kinetic ring current models bounce-averaged Fokker-Planck equation Earth inner magnetosphere ring current dynamics magnetic storms

Influence of laser shock peening on microstructure and high-temperature oxidation resistance of Ti45Al8Nb alloy fabricated via laser melting deposition

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中国有色金属学报 2025年第1期35卷 157-168页

作者： lu-lu JIANG Liang LAN Cheng-yan BAI Ru-yi XIN Shuang GAO hao-yu WANG Bo HE Chao-yue CHEN Guo-xin lu Research Center of High-Temperature Alloy Precision Forming School of Materials Science and EngineeringShanghai University of Engineering ScienceShanghai 201620China State Key Laboratory of Advanced Special Steels School of Materials Science and EngineeringShanghai UniversityShanghai 200444China School of Materials Science and Engineering Shandong UniversityJinan 250061China

Laser shock peening(LSP)was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb *** microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb alloy before and after LSP were investigated by scanning electron microscopy,X-ray diffraction,and electron backscatter *** results indicated that the rate of mass gain in the as-deposited sample after LSP exhibited a decrease when exposed to an oxidation temperature of 900℃,implying that LSP-treated samples exhibited superior oxidation resistance at high temperatures.A gradient structure with a fine-grain layer,a deformed-grain layer,and a coarse-grain layer was formed in the LSP-treated sample,which facilitated the diffusion of the Al atom during oxidation,leading to the formation of a dense Al_(2)O_(3)layer on the *** mechanism of improvement in the oxidation resistance of the as-deposited Ti45Al8Nb alloy via LSP was discussed.

关键词： TiAl alloy laser melting deposition laser shock peening additive manufacturing oxidation resistance

Advanced dielectrics for 2D devices

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Science Bulletin 2025年第3期70卷 295-296页

作者： hao Zhang Zhiwen lu Zhenhai Wen Department of Chemical Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA Department of Chemistry University of OxfordOxford OX13TAUK CAS Key Laboratory of Design and Assembly of Functional Nanostructures Fujian Provincial Key Laboratory of Materials and Techniques toward Hydrogen EnergyFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

As the application potential of two-dimensional(2D)materials in fields such as nanoelectronics,optoelectronics,and quantum computing continues to grow,the challenge of fabricating high-quality dielectric layers has be... 详细信息

关键词： computing continue devices

No-go guide for the Hubble tension:Late-time or local-scale new physics

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Science China(Physics,Mechanics & Astronomy) 2025年第2期68卷 73-85页

作者： lu Huang Shao-Jiang Wang Wang-Wei yu CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of Sciences(CAS)Beijing100190China Asia Pacific Center for Theoretical Physics(APCTP) Pohang37673Korea Max-Planck-Institut für Gravitationsphysik(Albert-Einstein-Institut) HannoverD-30167Germany Leibniz Universität Hannover Hannover30167Germany

The standard model of modern cosmology might be cracked by the recent persistent hot debate on the Hubble-constant(H_(0))tension,which manifests itself as the sound-horizon(r_(s))tension or absolute-magnitude(M_(B))tension if deeming the origin of the Hubble tension from modifying the early or late Universe,*** this study,we achieve a fully model-independent constraint(fitting a model-independent global parameterization to a model-independent inverse distant ladder with a modelindependent high-redshift calibration)on late-time models with strong evidence against homogeneous new physics over theΛ-cold-dark-matter(ΛCDM)*** using this model-independent constraint to calibrate sufficiently local supernovae with corresponding late-time models extrapolated below the homogeneity scale,we find surprisingly that,although both H_(0)tension and MB tension are absent in our local Universe,a combination of H_(0)and M_(B)as the intercept a B of the magnitude-redshift relation exhibits 3~7σtension even for theΛCDM *** aBtension seems to call for local-scale inhomogeneous new physics disguised as local observational systematics.

关键词： Hubble constant inverse distance ladder local Universe

Spatio-temporal patterns and climatic drivers of spring phenology in eight forest communities across the north-south transitional zone of China

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Journal of Geographical Sciences 2025年第1期35卷 17-38页

作者： ZHU Wenbin lu yu Institute of Geographic Sciences and Natural Resources Research CASBeijing100101China School of Geographical Science Nanjing University of Information Science&TechnologyNanjing210044China

The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of *** of its phenology is critical for comprehending the response of vegetation to climatic *** retrieved the start of spring phenology(SOS)of eight forest communities from the MODIS products and adopted it as an indicator for spring *** analysis,partial correlation analysis,and GeoDetector were employed to reveal the spatio-temporal patterns and climatic drivers of *** results indicated that the SOS presented an advance trend from 2001 to 2020,with a mean rate of−0.473 d yr^(−1).The SOS of most forests correlated negatively with air temperature(TEMP)and positively with precipitation(PRE),suggesting that rising TEMP and increasing PRE in spring would forward and delay SOS,*** dominant factors influencing the sensitivity of SOS to climatic variables were altitude,forest type,and latitude,while the effects of slope and aspect were relatively *** response of SOS to climatic factors varied significantly in space and among forest communities,partly due to the influence of altitude,slope,and aspect.

关键词： spring phenology climatic drivers altitude forest communities lag effect Qinba Mountains

Numerical Study of Cavitating Flows around a Hydrofoil with Deep Analysis of Vorticity Effects

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Fluid Dynamics & Materials Processing 2025年第1期21卷 179-204页

作者： Shande Li Wen’an Zhong Shaoxing yu hao Wang Xichang Satellite Launch Center Wenchang571300China College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China

This paper aims to numerically explore the characteristics of unsteady cavitating flow around a NACA0015 hydrofoil,with a focus on vorticity *** simulation utilizes a homogeneous mixture model coupled with a filter-based density correction turbulence model and a modified Zwart cavitation *** study investigates the dynamic cavitation features of the thermal fluid around the hydrofoil at various incoming flow *** systematically elucidates the evolution of cavitation and vortex dynamics corresponding to each velocity *** results indicate that with increasing incoming flow velocity,distinct cavitation processes take place in the flow field.

关键词： Cavitating flow hydrofoil flow velocity vorticity Computational Fluid Dynamics(CFD)

Optimal condition analysis of target localization using multi-agents with uncertain positions

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CONTROL THEORY AND TECHNOLOGY 2025年第1期23卷 131-144页

作者： Hou, Yi hao, Ning He, Fenghua Xie, Chen Yao, yu Harbin Inst Technol Sch Aerosp Harbin 150001 Heilongjiang Peoples R China

This paper delves into the problem of optimal placement conditions for a group of agents collaboratively localizing a target using range-only or bearing-only measurements. The challenge in this study stems from the uncertainty associated with the positions of the agents, which may experience drift or disturbances during the target localization process. Initially, we derive the Cramer-Rao lower bound (CRLB) of the target position as the primary analytical metric. Subsequently, we establish the necessary and sufficient conditions for the optimal placement of agents. Based on these conditions, we analyze the maximal allowable agent position error for an expected mean squared error (MSE), providing valuable guidance for the selection of agent positioning sensors. The analytical findings are further validated through simulation experiments.

关键词： Cramer-Rao lower bound (CRLB) Target localization Uncertain sensor position Multi-agent systems

Federated local causal structure learning

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Science China(Information Sciences) 2025年第03期68卷 110-124页

作者： Kui yu Chen RONG hao WANG Fuyuan CAO Jiye LIANG School of Computer and Information Hefei University of Technology School of Computer and Information Technology Shanxi University

Local causal structure learning(LCS) efficiently identifies a set of direct neighbors of a specified variable from observational data. Additionally, it distinguishes direct causes and direct effects of this variable without learning the entire causal structure. While many LCS algorithms have been proposed, they do not consider the data privacy-preserving problem,which has attracted extensive attention from academia and industry. To address this issue, we propose a federated local causal structure learning(FedLCS) algorithm to learn local causal structures in privacy-preserving data in a federated ***, FedLCS introduces a layer-wise federated local skeleton learning algorithm to construct the local skeleton. Based on this skeleton, it introduces a federated local skeleton orientation algorithm and an extension-and-backtracking orientation algorithm to orient the edges. Finally, FedLCS uses a federated local extension-and-backtracking orientation algorithm to orient the remaining edges. Extensive experiments on benchmark, synthetic, and real datasets demonstrate that FedLCS can learn the local causal structure of a given variable in a federated setting.

关键词： local causal structure learning federated learning directed acyclic graph privacy-preserving data federated layer-wise strategy

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Xiangshao Granules Ameliorate Post-stroke Depression by Inhibiting Activation of Microglia and IDO1 Expression in Hippocampus and Prefrontal Cortex

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Chinese Journal of Integrative Medicine 2025年第1期31卷 28-38页

作者： LI Cheng-gang XU lu-shan SUN Liang XU yu-hao CAO Xiang Zhao Chen-chen XIA Sheng-nan ZHANG Qing-xiu XU yun Department of Neurology Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing210008China State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases Nanjing UniversityNanjing210008China Jiangsu Key Laboratory for Molecular Medicine Medical School of Nanjing UniversityNanjing210008China Nanjing Neurology Medical Center Nanjing210008China

Objective To investigate the therapeutic effect of Xiangshao Granules(XSG)on post-stroke depression(PSD)and explore the underlying *** Forty-three C57BL/6J mice were divided into 3 groups:sham(n=15),PSD+vehicle(n=14),and PSD+XSG(n=14)groups according to a random number *** PSD models were constructed using chronic unpredictable mild stress(CUMS)after middle cerebral artery occlusion(MCAO).The sham group only experienced the same surgical operation,but without MACO and CUMS *** XSG group received XSG(60 mg/kg per day)by gavage for 4 *** mice in the sham and vehicle groups were given the same volume of 0.9%saline at the same *** body weight and behavior tests including open field test,sucrose preference test,tail suspension test,and elevated plus-maze test,were used to validate the PSD mouse ***-time fluorescence quantitative polymerase chain reaction(RT-qPCR),enzyme-linked immunosorbent assay(ELISA),and immunofluorescence staining were used to evaluate the anti-inflammatory effects of *** potential molecular mechanisms were explored and verified through network pharmacology analysis,Nissl staining,Western blot,ELISA,and RT-qPCR,*** The body weight and behavior tests showed that MCAO combined with CUMS successfully established the PSD *** alleviated neuronal damage,reduced the expressions of pro-apoptotic proteins Caspase-3 and B-cell lymphoma-2(BCL-2)-associated X(BAX),and increased the expression of anti-apoptotic protein BCL-2 in PSD mice(Pluding tumor necrosis factor-α,interleukin(IL)-1β,and IL-6 via the toll-like receptor 4/nuclear factor kappa-B signaling pathway in PSD mice(Plusion XSG could reverse

关键词： post-stroke depression Xiangshao Granules indoleamine 2,3-dioxygenase 1 Chinese medicine