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Statistical characteristics and classification of ionospheric mid-latitude trough as revealed by the observations of DMSP-F18

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Earth and Planetary Physics 2025年第1期9卷 137-147页

作者： Yi Liu JiuHou Lei FuQing Huang Su zhou School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of Science Guiyang UniversityGuiyang 550005China

Statistical characteristics and the classification of the topside ionospheric mid-latitude trough are systemically analyzed,using observations from the Defense Meteorological Satellite Program F18(DMSP-F18)*** data was obtained at an altitude of around 860 km in near polar orbit,throughout *** study identified the auroral boundary based on the in-situ electron density and electron spectrum,allowing us to precisely determine the location of the mid-latitude *** differs from most previous works,which only use Total Electron Content(TEC)or in-situ electron *** our study,the troughs exhibited a higher occurrence rate in local winter than in summer,and extended to lower latitudes with increasing geomagnetic *** was found that the ionospheric mid-latitude trough,which is associated with temperature changes or enhanced ion drift,exhibited distinct ***,the ionospheric mid-latitude troughs related to electron temperature(Te)peak were located more equatorward of auroral oval boundary in winter than in *** ionospheric mid-latitude troughs related to Te-maximum were less frequently observed at 60−70°S magnetic latitude and 90−240°E ***,the troughs related to ion temperature(Ti)maximums were observed at relatively higher latitudes,occurring more frequently in *** addition,the troughs related to ion velocity(Vi)maximums could be observed in all *** troughs with the maximum-Ti and maximum-Vi were located closer to the equatorward boundary of the auroral oval at the nightside,and in both *** implies that enhanced ion drift velocity contributes to increased collisional frictional heating and enhanced ion temperatures,resulting in a density depletion within the trough region.

关键词： topside ionosphere mid-latitude trough ionospheric main trough auroral oval boundary temperature maximum

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Grounded-source short offset transient electromagnetic method:Theory and applications in deep mineral exploration

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Science China Earth Sciences 2025年

作者： Guoqiang XUE Xin WU Weiying CHEN Nannan zhou Key Laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences College of Earth and Planetary Sciences University of Chinese Academy of Sciences

Abstract The Transient Electromagnetic (TEM) method is a critical geophysical technique for subsurface exploration of metal ore bodies, primarily utilizing either loop or grounded transmitters. The Long Offset Transient Electromagnetic(LOTEM) method employs a grounded-source transmitter, relying on a far-source observation mode and plane wave approximation for detection. However, LOTEM’s far-source configuration weakens signal strength, and the plane wave approximation reduces precision, limiting effective detection depth to approximately 1000 m with a comprehensive error of about 15%. Recently, we have developed the grounded-source Short Offset Transient Electromagnetic (SOTEM) method,achieving greater detection depth and accuracy within the 500–2000 m depth range, a crucial interval for mineral resource exploration. This study explores the theoretical framework, instrumentation, data processing, and field applications of SOTEM. Based on a point charge element model, SOTEM accurately computes surface wave effects in EM field calculations,optimized for near-source observation. High-power, high-resolution, wide-bandwidth exploration equipment and an advanced three-dimensional hybrid inversion technique were also developed to enhance the method’s effectiveness. Application of SOTEM to the deep exploration of the zhou’an Ni-Cu-PGE deposit in Henan Province yielded high-resolution imaging of conductivity structures to about 2.5 km depth. These results, consistent with existing drill data, delineated mineralized ore bodies from surrounding formations, identified zones of mineralization potential, and suggested extensive resource prospects in the region.

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Circle of Friends

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China Today 2025年第1期74卷 32-35页

作者： zhou LIN 不详

CISCE brings together partners on the global industrial chain to collaborate and enhance global *** in South Yorkshire in north-central England,British Steel,originally founded in 1967,is the U.K.’s only manufacturer of *** now produces three million tons of crude steel annually and has the distinction of maintaining stable production even during the COVID-19 pandemic,with its ironmaking,steelmaking and all rolling mills in full operation.

关键词： annually partner CISC

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Vertical gradients of neutral winds observed by ICON and estimated by the Horizontal Wind Model during the geomagnetic storm on August 26−28,2021

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Earth and Planetary Physics 2025年第1期9卷 69-80页

作者： JiaWei Wu Chao Xiong YuYang Huang YunLiang zhou Department of Space Physics School of Electronic InformationHubei Luojia LaboratoryWuhan UniversityWuhan 430072China

The Michelson Interferometer for Global High-resolution Thermospheric Imaging(MIGHTI)onboard the Ionospheric Connection Explorer(ICON)satellite offers the opportunity to investigate the altitude profile of thermospheric *** this study,we used the red-line measurements of MIGHTI to compare with the results estimated by Horizontal Wind Model 14(HWM14).The data selected included both the geomagnetic quiet period(December 2019 to August 2022)and the geomagnetic storm on August 26-28,*** the geomagnetic quiet period,the estimations of neutral winds from HWM14 showed relatively good agreement with the observations from *** to the ICON observations,near the equator,zonal winds reverse from westward to eastward at around 06:00 local time(LT)at higher altitudes,and the stronger westward winds appear at later LTs at lower *** around 16:00 LT,eastward winds at 300 km reverse to westward,and vertical gradients of zonal winds similar to those at sunrise hours can be *** the middle latitudes,zonal winds reverse about 2-4 h *** winds vary more significantly than zonal winds with seasonal and latitudinal *** to the ICON observations,in the northern low latitudes,vertical reversals of meridional winds are found at 08:00-13:00 LT from 300 to 160 km and at around 18:00 LT from 300 to 200 km during the June *** reversals of meridional winds are found at 04:00-07:00 LT from 300 to 160 km and at 22:00-02:00 LT from 270 to 200 km during the December *** the southern low latitudes,meridional wind reversals occur at 08:00-11:00 LT from 200 to 160 km and at 21:00-02:00 LT from 300 to 200 km during the June *** the December solstice,reversals of the meridional wind appear at 20:00-01:00 LT below 200 km and at 06:00-11:00 LT from 300 to 160 *** the northern middle latitudes,the northward winds are dominant at 08:00-14:00 LT at 230 km during the June *** winds persist until

关键词： horizontal neutral winds vertical gradients Ionospheric Connection Explorer satellite Horizontal Wind Model 14 geomagnetic storm

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Righting Wrongs

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China Today 2025年第1期74卷 45-47页

作者： zhou LIN 不详

Representatives from nearly 50 countries and regions share their thoughts on how to correct development imbalances and protect people’s rights in all ***,a small village in Zhejiang Province,is known for its beautiful scenery,with white egrets flying in a blue sky and mandarin fish jumping out of the clear water of its lakes and *** houses are equally picturesque,dainty three-storied villas with white walls and black tiles.

关键词： walls beautiful white

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High-dimensional large-scale mixed-type data imputation under missing at random

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Science China Mathematics 2025年

作者： Wei Liu Guizhen Li Ling zhou Lan Luo School of Mathematics Sichuan University Center of Statistical Research and School of Statistics Southwestern University of Finance and Economics Department of Statistics and Actuarial Science University of Iowa

Missingness in mixed-type variables is commonly encountered in a variety of areas. The requirement of complete observations necessities data imputation when a moderate or large proportion of data is ***, inappropriate imputation would downgrade the performance of machine learning algorithms, leading to bad predictions and unreliable statistical inference. For high-dimensional large-scale mixed-type missing data, we develop a computationally efficient imputation method, missing value imputation via generalized factor models（MIG）, under missing at random. The proposed MIG method allows missing variables to be of different types,including continuous, binary, and count variables, and are scalable to both data size n and variable dimension p while existing imputation methods rely on restrictive assumptions such as the same type of missing variables,the low dimensionality of variables, and a limited sample size. We explicitly show that the imputation error of the proposed MIG method diminishes to zero with the rate Op(max{n-1/2, p-1/2}) as both n and p tend to infinity. Five real datasets demonstrate the superior empirical performance of the proposed MIG method over existing methods that the average normalized absolute imputation error is reduced by 5.3%–34.1%.

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Effects of mesoscale gravity waves on sporadic E simulated by a one-dimensional dynamic model

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

作者： Xu zhou ZeZhong Li XinAn Yue LiBo Liu Key Laboratory of Earth and Planetary Physics/Heilongjiang Mohe National Geophysical Observatory/Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences(CAS)Beijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China

In addition to being driven by tidal winds,the sporadic E(Es)layers are modulated by gravity waves(GWs),although the effects are not yet comprehensively *** this article,we discuss the effects of mesoscale GWs on the Es layers determined by using a newly developed model,MISE-1D(one-dimensional Model of Ionospheric Sporadic E),with low numerical dissipation and high *** by the wind fields resolved by the high-resolution version of the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension(WACCM-X),the MISE-1D simulation revealed that GWs significantly influence the evolution of the Es layer above 100 km but have a very limited effect at lower *** effects of GWs are diverse and complex,generally including the generation of fluctuating wavelike structures on the Es layer with frequencies similar to those of the *** mesoscale GWs can also cause increases in the density of Es layers,or they can disperse or diffuse the Es layers and increase their *** addition,the presence of GWs is a key factor in sustaining the Es layers in some cases.

关键词： sporadic E ion tidal layer gravity waves numerical simulation

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Exploring the spatiotemporal heterogeneity of vegetation changes in subtropical humid karst region under CO2 fertilization

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Journal of Geographical Sciences 2025年第1期35卷 65-87页

作者： CHEN Meng zhou Qiuwen PENG Dawei YAN Weihong School of Geography and Environmental Science Guizhou Normal University Huanjiang Observation and Research Station for Karst Ecosystem Guangxi Key Laboratory of Karst Ecological Processes and Services Institute of Subtropical Agriculture CAS University of Chinese Academy of Sciences Faculty of Geographical Science Beijing Normal University Forestry Bureau of Shibing County

Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide （CO2） fertilization in hot and humid *** subtropical humid karst region is a hot and humid region;whether and to what extent CO2fertilization affects vegetation changes in such regions remains *** this study,we investigated the degree to which CO2fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression *** showed that CO2fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO2fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau *** studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these *** findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.

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A matrix metalloproteinase-responsive hydrogel system controls angiogenic peptide release for repair of cerebral ischemia/reperfusion injury

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Neural Regeneration Research 2025年第2期20卷 503-517页

作者： Qi Liu Jianye Xie Runxue zhou Jin Deng Weihong Nie Shuwei Sun Haiping Wang Chunying Shi Department of Human Anatomy Histology and EmbryologySchool of Basic MedicineQingdao UniversityQingdaoShandong ProvinceChina Department of Neurology The Affiliated Hospital of Qingdao UniversityQingdaoShandong ProvinceChina Department of General Practice The Affiliated Hospital of Qingdao UniversityQingdaoShandong ProvinceChina

Vascular endothelial growth factor and its mimic peptide KLTWQELYQLKYKGI(QK)are widely used as the most potent angiogenic factors for the treatment of multiple ischemic ***,conventional topical drug delivery often results in a burst release of the drug,leading to transient retention(inefficacy)and undesirable diffusion(toxicity)in ***,a drug delivery system that responds to changes in the microenvironment of tissue regeneration and controls vascular endothelial growth factor release is crucial to improve the treatment of ischemic *** metalloproteinase-2(MMP-2)is gradually upregulated after cerebral ***,vascular endothelial growth factor mimic peptide QK was self-assembled with MMP-2-cleaved peptide PLGLAG(TIMP)and customizable peptide amphiphilic(PA)molecules to construct nanofiber hydrogel ***-TIMP-QK was found to control the delivery of QK by MMP-2 upregulation after cerebral ischemia/reperfusion and had a similar biological activity with vascular endothelial growth factor in *** results indicated that PA-TIMP-QK promoted neuronal survival,restored local blood circulation,reduced blood-brain barrier permeability,and restored motor *** findings suggest that the self-assembling nanofiber hydrogel PA-TIMP-QK may provide an intelligent drug delivery system that responds to the microenvironment and promotes regeneration and repair after cerebral ischemia/reperfusion injury.

关键词： angiogenesis biomaterial blood-brain barrier cerebral ischemia/reperfusion injury control release drug delivery inflammation QK peptides matrix metalloproteinase-2 neuroprotection self-assembling nanofiber hydrogel

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Optimizing electronic structure through point defect engineering for enhanced electrocatalytic energy conversion

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Green Energy & Environment 2025年第1期10卷 109-131页

作者： Wei Ma Jiahao Yao Fang Xie Xinqi Wang Hao Wan Xiangjian Shen Lili Zhang Menggai Jiao Zhen zhou Interdisciplinary Research Center for Sustainable Energy Science and Engineering(IRC4SE2) School of Chemical EngineeringZhengzhou UniversityHenan450001China

Point defect engineering endows catalysts with novel physical and chemical properties,elevating their electrocatalytic *** introduction of defects emerges as a promising strategy,effectively modifying the electronic structure of active *** optimization influences the adsorption energy of intermediates,thereby mitigating reaction energy barriers,altering paths,enhancing selectivity,and ultimately improving the catalytic efficiency of *** elucidate the impact of defects on the electrocatalytic process,we comprehensively outline the roles of various point defects,their synthetic methodologies,and characterization ***,we consolidate insights into the relationship between point defects and catalytic activity for hydrogen/oxygen evolution and CO_(2)/O_(2)/N_(2) reduction reactions by integrating mechanisms from diverse *** underscores the pivotal role of point defects in enhancing catalytic *** last,the principal challenges and prospects associated with point defects in current electrocatalysts are proposed,emphasizing their role in advancing the efficiency of electrochemical energy storage and conversion materials.

关键词： Point defect engineering Doping Vacancy Electrocatalysis Electronic structure

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