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Automatic recognition of landslides based on YOLOv7 and attention mechanism

Journal of Mountain Science 2024年第8期21卷 2681-2695页

作者： SONG Yewei GUO Jie WU Gaofeng MA Fengshan LI Fangrui Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Sciences Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Landslide disasters comprise the majority of geological incidents on slopes,posing severe threats to the safety of human lives and property while exerting a significant impact on the geological *** rapid identification of landslides is important for disaster prevention and control;however,currently,landslide identification relies mainly on the manual interpretation of remote sensing *** interpretation and feature recognition methods are time-consuming,labor-intensive,and challenging when confronted with complex ***,automatic landslide recognition has emerged as a pivotal avenue for future *** this study,a dataset comprising 2000 landslide images was constructed using open-source remote sensing images and *** YOLOv7 model was enhanced using data augmentation algorithms and attention *** optimization models were formulated to realize automatic landslide *** findings demonstrate the commendable performance of the optimized model in automatic landslide recognition,achieving a peak accuracy of 95.92%.Subsequently,the optimized model was applied to regional landslide identification,co-seismic landslide identification,and landslide recognition at various scales,all of which showed robust recognition ***,the model exhibits limitations in detecting small targets,indicating areas for refining the deep-learning *** results of this research offer valuable technical support for the swift identification,prevention,and mitigation of landslide disasters.

关键词： Deep learning Landslide detection Natural disasters Attention mechanism Remote sensing

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Extreme value theory applied to the auroral electrojet indices

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Earth and Planetary Physics 2024年第2期8卷 375-381页

作者： Si Chen Hong Yuan Yong Wei Guang Yang FengZheng Yu Aerospace Information Research institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The study of extreme weather and space events has gained paramount importance in modern society owing to rapid advances in high *** and describing exceptional occurrences plays a crucial role in making decisive assessments of their potential impact on technical,economic,and social aspects in various *** research focuses on analyzing the hourly values of the auroral electrojet(AE)geomagnetic index from 1957 to 2019 by using the peak over threshold method in extreme value *** fitting the generalized Pareto distribution to extreme AE values,shape parameter indices were derived,revealing negative values that establish an upper bound for this time ***,it became evident that the AE values had reached a plateau,suggesting that extreme events exceeding the established upper limit are *** a result,although the need for diligent precautions to mitigate the consequences of such extreme events persists,surpassing the upper limit of AE values becomes increasingly *** is also possible to observe an aurora in the middle-and low-latitude regions during the maximum period of the AE index.

关键词： auroral electrojet indices extreme value theory extreme events

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Benchmark experiment on slab^(238)U with D-T neutrons for validation of evaluated nuclear data

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nuclear Science and Techniques 2024年第2期35卷 145-159页

作者： Yan-Yan Ding Yang-Bo Nie Yue Zhang Zhi-Jie Hu Qi Zhao Huan-Yu Zhang Kuo-Zhi Xu Shi-Yu Zhang Xin-Yi Pan Chang-Lin Lan Jie Ren Xi-Chao Ruan Key Laboratory of nuclear Data China Institute of Atomic EnergyBeijing 102413China School of nuclear Science and Technology Lanzhou UniversityLanzhou 730000China institute of Fluid Physics China Academy of Engineering PhysicsMianyang 62100China

A benchmark experiment on^(238)U slab samples was conducted using a deuterium-tritium neutron source at the china institute of Atomic *** leakage neutron spectra within energy levels of 0.8-16 MeV at 60°and 120°were measured using the time-of-flight *** samples were prepared as rectangular slabs with a 30 cm square base and thicknesses of 3,6,and 9 *** leakage neutron spectra were also calculated using the MCNP-4C program based on the latest evaluated files of^(238)U evaluated neutron data from CENDL-3.2,ENDF/B-Ⅷ.0,JENDL-5.0,and *** on the comparison,the deficiencies and improvements in^(238)U evaluated nuclear data were *** results showed the following.(1)The calculated results for CENDL-3.2 significantly overestimated the measurements in the energy interval of elastic scattering at 60°and 120°.(2)The calculated results of CENDL-3.2 overestimated the measurements in the energy interval of inelastic scattering at 120°.(3)The calculated results for CENDL-3.2 significantly overestimated the measurements in the 3-8.5 MeV energy interval at 60°and 120°.(4)The calculated results with JENDL-5.0 were generally consistent with the measurement results.

关键词： Leakage neutron spectra Uranium D-T neutron source Evaluated nuclear data

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Multiple thermal events recorded in the Acasta Gneiss Complex:Evidence from in-situ dating of zircon, titanite, and apatite

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Science china Earth Sciences 2024年第3期67卷 673-686页

作者： Qingfeng MEI Jinhui YANG Jinfeng SUN Qiuli LI Shitou WU Xiaoxiao LING Peng PENG Hao WANG State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing 100049China

In-situ dating of the zircons, titanites, and apatites in the rock fragments of approximately 1 cm2in size from the Acasta Gneiss Complex was performed using secondary ion mass spectrometry or laser ablation inductively coupled plasma mass spectrometry to provide constraints on the thermal history of the Acasta Gneiss Complex. The zircons in these rock fragments typically exhibit multiple age populations, reflecting the presence of inherited zircons or the post-crystallization process of zircon overgrowth. Combined with previous studies, our zircon dating results reveal multiple magmatic events that occurred in the Acasta Gneiss Complex, specifically at >3.96, ~3.72, and ~3.57 Ga, respectively. A titanite Pb-Pb isochron age of2911±22 Ma(95% confidence level, MSWD=1.5) for sample AY199 is identified, consistent with the timing of the latest Archean magmatism in the Acasta Gneiss Complex. The titanite U-Pb ages for samples AC478 and AY066 are 1932±270 Ma(95% confidence level, MSWD=2.3) and 1813±45 Ma(95% confidence level, MSWD=2.3), respectively. The apatites in sample P090803-C exhibit a Pb-Pb isochron age of 1833±26 Ma(95% confidence level, MSWD=1.4). The apatite U-Pb ages for samples AC478, AY199, and AY066 are 1850±20 Ma(95% confidence level, MSWD=1.3), 1827±100 Ma(95% confidence level, MSWD=6.3), and 1807±58 Ma(95% confidence level, MSWD=3.9), respectively. Titanites in samples AC478 and AY066, as well as the apatites in all four investigated samples, show a uniform age(Pb-Pb or U-Pb age) of ~1.9–1.8 Ga,indicating U-Pb system reset in these minerals due to the Wopmay orogeny and documenting that the peak temperature condition associated with the Wopmay orogeny exceeded the apatite U-Pb closure temperature and approached or exceeded that of titanite.

关键词： Zircon Titanite Apatite Acasta Gneiss Complex Wopmay Orogen

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Human radiological safety assessment for petawatt laser-driven ion acceleration experiments in CLAPA-T

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Matter and Radiation at Extremes 2024年第4期9卷 8-15页

作者： Xiaopeng Zhang Jiarui Zhao Shengxuan Xu Xun Chen Ying Gao Shiyou Chen Kun Zhu Xueqing Yan Wenjun Ma State Key Laboratory of nuclear Physics and Technology and Key Laboratory of HEDP of the Ministry of EducationCAPTPeking UniversityBeijing 100871China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsCASBeijing 100049China beijing Laser Acceleration Innovation Center HuairouBeijing 101400China institute of Guangdong Laser Plasma Technology BaiyunGuangzhou 510540China

The newly built Compact Laser Plasma Accelerator-Therapy facility at Peking University will deliver 60 J/1 Hz laser pulses with 30 fs *** by this petawatt laser facility,proton beams with energy up to 200 MeV are expected to be generated for tumor *** high-repetition operation,both prompt radiation and residual radiation may cause safety ***,human radiological safety assessment before commissioning is *** this paper,we simulate both prompt and residual radiation using the Geant4 and FLUKA Monte Carlo codes with reasonable proton and as-produced electron beam *** find that the prompt radiation can be shielded well by the concrete wall of the experimental hall,but the risk from residual radiation is nonnegligible and necessitates adequate radiation *** the basis of the simulation results,we discuss the constraints imposed by radiation safety considerations on the annual working time,and we propose radiation cooling strategies for different shooting modes.

关键词： laser prompt acceleration

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Effect of Al_(2)O_(3)on the Mechanical Properties of(B_(4)C+Al_(2)O_(3))/Al Neutron Absorbing Materials

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Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1411-1420页

作者： J.X.Cai B.M.Shi N.Li Y.Liu Z.G.Zhang Y.N.Zan Q.Z.Wang B.L.Xiao Z.Y.Ma Shi‑Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key Laboratory of nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.Ltd.Beijing 100840China Department of Materials Science School of Mechanical EngineeringShenyang UniversityShenyang 110044China

B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear *** order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder *** this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(B_(4)C+Al_(2)O_(3))/Al *** was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high *** the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased *** finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.

关键词： Al matrix composites Neutron absorbing materials (B_(4)C+Al_(2)O_(3))/Al composites High-temperature strength

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Effect of Interface Form on Creep Failure and Life of Dissimilar Metal Welds Involving Nickel-Based Weld Metal and Ferritic Base Metal

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 265-285页

作者： Xiaogang Li Junfeng Nie Xin Wang Kejian Li Haiquan Zhang institute of nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

For dissimilar metal welds(DMWs)involving nickel-based weld metal(WM)and ferritic heat resistant steel base metal(BM)in power plants,there must be an interface between WM and BM,and this interface suffers mechanical and microstructure mismatches and is often the rupture location of premature *** this study,a new form of WM/BM interface form,namely double Y-type interface was designed for the *** behaviors and life of DMWs containing double Y-type interface and conventional I-type interface were compared by finite element analysis and creep tests,and creep failure mechanisms were investigated by stress-strain analysis and microstructure *** applying double Y-type interface instead of conventional I-type interface,failure location of DMW could be shifted from the WM/ferritic heat-affected zone(HAZ)interface into the ferritic HAZ or even the ferritic BM,and the failure mode change improved the creep life of *** interface premature failure of I-type interface DMW was related to the coupling effect of microstructure degradation,stress and strain concentrations,and oxide notch on the WM/HAZ *** creep failure of double Y-type interface DMW was the result of Type IV fracture due to the creep voids and micro-cracks on fine-grain boundaries in HAZ,which was a result of the matrix softening of HAZ and lack of precipitate pinning at fine-grain *** double Y-type interface form separated the stress and strain concentrations in DMW from the WM/HAZ interface,preventing the trigger effect of oxide notch on interface failure and inhibiting the interfacial microstructure *** is a novel scheme to prolong creep life and enhance reliability of DMW,by means of optimizing the interface form,decoupling the damage factors from WM/HAZ interface,and then changing the failure mechanism and shifting the failure location.

关键词： Dissimilar metal weld Nickel-based weld metal Ferritic heat resistant steel Interface Creep strain Microstructure Failure mechanism Creep life

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Failure Analysis of Dissimilar Metal Welds between Ferritic Heat Resistant Steels and Austenitic Stainless Steels in Power Plant

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 306-326页

This study analysed the failure of dissimilar metal welds(DMWs)between ferritic heat resistant steels and austenitic stainless steels and investigated its influencing factors by means of numerical simulation,microstructure characterization and mechanical property *** the long-term high-temperature service condition in practical power plant,the DMW failure mode was along the interface between nickel-based weld metal(WM)and ferritic heat resistant steel,and the failure mechanism was stress/strain concentration,microstructure degradation and oxidation coupling acting on the *** numerical simulation results show that interface stress/strain concentration was due to the differences in coefficient of thermal expansion and creep strength,and the degree of stress/strain concentration was related to service *** ferrite band formed at the WM/ferritic steel interface was prone to cracking,attracting the fracture along the *** interface crack allowed oxidation to develop along the WM/ferritic steel *** long-term service,the interface stress/strain concentration,microstructure and oxidation all evolved,which synergistically promoted interface failure of ***,only under the long-term service of low stress conditions could trigger the interface failure of ***,long-term service would reduce the mechanical strength and plasticity of DMW.

关键词： Dissimilar metal weld Failure Interface Stress/strain concentration Microstructure Oxidation

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Multi-spherical interactions and mechanisms of hydrocarbon enrichment in the Southeast Asian archipelagic tectonic system

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Science china Earth Sciences 2024年第2期67卷 566-583页

作者： Rixiang ZHU Hongjun WANG Huajian WANG Xiaomei WANG Bo WAN Wang ZHANG Houqin ZHU Yuke LIU Junlai LIU Qingren MENG Fang HAO Zhijun JIN State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China State Key Laboratory of Enhanced Oil and Gas Recovery PetroChina Research Institute of Petroleum Exploration and DevelopmentBeijing100083China School of Earth Sciences and Resources China University of GeosciencesBeijing100083China State Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580China institute of Energy Peking UniversityBeijing100871China

Global cooling began since 50 Ma,but a warm climate was maintained in the archipelagic tectonic system in Southeast Asia where a wealth of Cenozoic oil and gas resources was formed and *** the perspective of Earth system,this study analyzes Cenozoic tectonic activities,climatic and environmental evolution,and petroleum enrichment in Southeast Asia,and provides the following insights:(1)Subduction of oceanic plates and the extension of overlying continental lithosphere resulted in widespread volcanic eruptions as well as the formation of rift basins and shallow marine shelves,leading to complex interactions between deep tectonic processes and Earth’s surface including mountains,basins,and seas.(2)Microcontinental accretion and prolonged stay in equatorial low-latitude regions have changed trade winds into monsoons,altered ocean current pathways and flow rates,and profoundly affected rainfall and climate.(3)The archipelagic tectonic system,coupled with a hot and rainy climate,fostered tropical rainforests,mangroves,and phytoplankton,providing abundant organic matter and promoting the development of petroleum resources.(4)Combinations of rift basin development and marine transgression and regression led to an effective superposition of source-reservoir-seal combinations from multiplepetroleum *** deep burial of organic matter and high geothermal gradients facilitated the generation and large-scale accumulation of oil and gas.(5)Multi-spherical(such as atmosphere,biosphere,hydrosphere and lithosphere)interactions on the Earth,which resulted from the convergence of multiple tectonic plates,are believed as the primary driver for exceptional enrichments of Cenozoic oil and gas resources in Southeast *** understandings are significant for developing theories of oil and gas enrichment under the guidance of Earth System *** order to continue making significant oil and gas exploration discoveries in the deep-layers,deep-waters,and unconventio

关键词： Southeast Asia Archipelagic tectonic system Interactions of Earth’s spheres Oil and gas resources Cenozoic

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Analysis and Monitoring of Indoor Radon Concentrations of 37 Kindergartens — beijing Municipality, china, 2023

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china CDC weekly 2024年第13期6卷 272-276页

作者： Meinan Yao Kuke Ding Xiaozhe Tang Yunyun Wu Yanchao Song Shuyuan Liu Bin Bai Li Zhang Yongzhong Ma institute for Radiation Hygiene Protection Beijing Center for Disease Prevention and ControlBeijingChina Chinese Center for Disease Control and Prevention BeijingChina Key Laboratory of Radiological Protection and nuclear Emergency&National institute for Radiological Protection Chinese Center for Disease Control and PreventionBeijingChina

Introduction:Radon(222Rn or 222radon)is a radioactive gas emitted from building materials,foundations,and *** are especially susceptible to radon exposure,underscoring the need to assess indoor radon levels in *** study monitored radon concentrations in 37 beijing kindergartens from June to October ***:A random sample of 37 kindergartens was selected from 18 administrative districts in *** indoor radon concentration was measured using the solid track accumulation method,with radon detectors continuously monitored over a 3-month ***:The mean indoor radon level in 37 kindergartens,observed at 252 monitoring points,was 84.3 Bq/m^(3),with values varying from 12.9 to 263.5 Bq/m^(3).About 20.2%of points showed radon levels between 100.0 and 200.0 Bq/m^(3),while 2.4%exceeded 200.0 Bq/m^(3).Notably,radon levels were significantly elevated on the ground floor compared to the upper ***:Indoor radon levels in 37 kindergartens remained below the national standard limit of 300.0 Bq/m^(3) for buildings(GB/T 16146-2015).Nonetheless,18.9%of the kindergartens exceeded the 100.0 Bq/m^(3) limit set for new *** is advised to improve radon monitoring in kindergartens and consider developing a national standard for maximum permissible radon levels in such facilities.

关键词： Radon limit floor

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