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3D robust anisotropic diffusion filtering algorithm for sparse view neutron computed tomography 3D image reconstruction

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Nuclear science and Techniques 2024年第3期35卷 13-29页

作者： Yang Liu Teng-fei Zhu zhi Luo Xiao-{2. Ouyang School of Nuclear science and Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi’an 710024China

The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed *** types of noise in the system can degrade the quality of the reconstructed ***,to improve the quality of the reconstructed images of NCT systems,efficient image processing algorithms must be *** anisotropic diffusion filtering(ADF) algorithm can not only effectively suppress the noise in the projection data,but also preserve the image edge structure information by reducing the diffusion at the image ***,we propose the application of the ADF algorithm for NCT image *** compare the performance of different algorithms in NCT systems,we reconstructed images using the ordered subset simultaneous algebraic reconstruction technique(OS-SART) algorithm with different regular terms as image processing *** the iterative reconstruction,we selected two image processing algorithms,the Total Variation and split Bregman solved total variation algorithms,for comparison with the performance of the ADF ***,the filtered back-projection algorithm was used for comparison with an iterative *** reconstructing the projection data of the numerical and clock models,we compared and analyzed the effects of each algorithm applied in the NCT *** on the reconstruction results,OS-SART-ADF outperformed the other algorithms in terms of denoising,preserving the edge structure,and suppressing *** example,when the 3D Shepp–Logan was reconstructed at 2. views,the root mean square error of OS-SART-ADF was the smallest among the four iterative algorithms,at only *** universal quality index,mean structural similarity,and correlation coefficient of the reconstructed image were the largest among all algorithms,with values of 0.9877,0.9878,and 0.9887,respectively.

关键词： NCT OS-SART Sparse-view Anisotropic diffusion filtering

Megafossils of Betulaceae from the Oligocene of Qaidam Basin and their paleoenvironmental and phytogeographic implications

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Plant Diversity 2024年第1期46卷 101-115页

作者： Tao Yang Jia-Hao Cai Yan-zhi Dai Hong-Yu Chen Lei Han Li zhang Wei-Yu Liang Xu-Jun Li Wen-Jia Li Jing-Yu Wu San-{2. Xie De-fei Yan School of Earth sciences and Key Laboratory of Mineral Resources in Western china(Gansu Province) Lanzhou UniversityLanzhou 730000China Key Laboratory of Vertebrate Evolution and Human Origins of Chinese academy of sciences Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of SciencesNanjing 210008China Center for Research and Education on Biological Evolution and Environments School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China

Understanding the paleoenvironment and phytogeographical history of the Tibetan Plateau,china relies on discovering new plant *** Qaidam Basin has long been regarded as an ideal‘field laboratory’to investigate the paleoclimate and paleobiological evolution of the northern Tibetan ***,fossil angiosperms from the Qaidam Basin are rare,and our knowledge of its paleovegetation is ***,we report fossil leaves and fruits of Betulaceae found from the Oligocene Shangganchaigou Formation of northwestern Qaidam Basin(Huatugou area).Comparative morphological analysis led us to assign the fruits to the Betula subgenus Betula and the leaves to Carpinus *** findings,together with other reported fossil plants from the same locality,reveal a close floristic linkage between the Qaidam Basin and Europe during the *** northern pathway of this floristic exchange may have crossed through the Qaidam Basin during the late *** floristic linkage may have been facilitated by the continuous narrowing of the Turgai Strait and stronger westerlies,which transported moisture and provided favorable climatic ***,fossil plants collected from the Qaidam Basin suggest that during the Oligocene this region had warm and humid deciduous broad-leaf forest,which differs from the region’s modern vegetation and indicates that the Qaidam Basin may have been a suitable region for these plants to flourish and spread during the Oligocene.

关键词： Paleoenvironment Biogeography Betulaceous fossil Qaidam basin Tibetan Plateau Oligocene

Stepped-up development of accelerator mass spectrometry method for the detection of ^(60)Fe with the HI-13 tandem accelerator

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Nuclear science and Techniques 2024年第4期35卷 136-143页

作者： Yang zhang Sheng-Quan Yan Ming He Qing-zhang Zhao Wen-Hui zhang Chao-Xin Kan Jian-Ming Zhou Kang-Ning Li Xiao-fei Wang Jian-Cheng Liu Zhao-Hua Peng Zhuo Liang Ai-Ling Li Jian Zheng Qi-Wen Fan Yun-Ju Li You-Bao Wang zhi-Hong Li Yang-ping Shen Ding Nan Wei Nan Yu-Qiang zhang Jia-Ying-Hao Li Jun-Wen Tian Jiang-Lin Hou Chang-Xin Guo zhi-Cheng zhang Ming-Hao Zhu Yu-Wen Chen Yu-Chen Jiang Tao Tian Jin-Long Ma Yi-Hui Liu Jing-Yu Dong Run-Long Liu Mei-Yue-Nan Ma Yong-Shou Chen Wei-ping Liu Bing Guo china Institute of Atomic Energy P.O.Box 275(10)Beijing 102413China College of science Southern University of Science and TechnologyShenzhen 518055China School of Physics Xi’an Jiaotong UniversityXi’an 710049China

The Moon provides a unique environment for investigating nearby astrophysical events such as *** samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)*** this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the china Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy *** particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the ***,an^(60)Fe sample with an abundance of 1.12.×10^(-10)was used to test the new AMS *** results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)*** sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.

关键词： Accelerator mass spectrometry Wien filter Isobar separation Supernovae Chang'e-5 lunar samples

Carbon Dioxide Fluxes and Concentrations in a Cotton Field in Northwestern china:Effects of Plastic Mulching and Drip Irrigation

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Pedosphere 2011年第2期21卷 178-185页

作者： LI zhi-Guo Key Laboratory of Oasis Ecology and Desert Environment Xinjiang Institute of Ecology and Geography Chinese Academy ofSciences Urumqi 830011 (China) Graduate University of Chinese academy of sciences Beijing 100049 (China) Institute of Soil science Chinese Academy of Sciences Nanjing 210008 (China) Earth System science Interdisciplinary Center University of Maryland College Park MD 20740 (USA)

In northwestern china, there has been a change from traditional cultivation system （TC） with no mulching and flood irrigation to a more modern cultivation system （MC） using plastic film mulching with drip irrigation. A field study was conducted to compare soil ＇C02.concentrations and soil surface COs fluxes between TC and MC systems during a cotton growing season. CO2.concentrations in the soil profile were higher in the MC system （3107-92.2.L L-1） than in the TC system （1 2.5-8994 μL L-1） but the rate of CO2.flux was lower in the MC system. Possible reasons for this included decreased gas diffusion and higher soil moisture due to the mulching cover in the MC system, and the consumption of soil CO2.by weathering reactions. Over the whole cotton growing season, accumulated rates of CO2.flux were 300 and 394 g C m-2.for the MC and TC systems, respectively. When agricultural practices were converted from traditional cultivation to a plastic film mulching system, soil CO2.emissions could be reduced by approximately 100 g C m-2.year-1 in agricultural lands in arid and/or semi-arid areas of northern and northwestern china.

关键词： agricultural practice carbon cycle greenhouse gas emission soil respiration weathering reaction

Frontiers in high entropy alloys and high entropy functional materials

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Rare Metals 2024年第10期43卷 4639-4776页

作者： Wen-Tao zhang Wen Huang Fu-Jie Yu Qi Zhao Xin-Dong Zhu Tao Feng Yao Jiang Xiao-Ming Li Xue-fei Miao He Zhu Si Lan Xue-Qian Wang Bao-Long Shen Zhe Jia Feng-Qi zhang Wei Wang Qi Liu Yang Ren Xun-Li Wang Xiao-Ya Cui Xiao-Yang Wang Ya-Nan Chen Bing-Bing Fan Meng-Ru Li Qi-Long Gao Jia-Ming Guo Zeng-Bao Jiao zhi-Min Guo Yu-ping Zhao Qian Yu Rui Huang Ling-Kun zhang Yi-ping Lu Xu-Bo Li Huai-Jun Lin Yan Ma Wei-Ming Yang zhi-Hua Shen Hai-Yan He Yong-Gang Sun Yong-Jiang Huang De-Zhuang Wang Qing-Feng Liu fei-Yang Wang Hui Liu Hong-Hui Wu Li-Qiang Wang Yang Lu Nan Wang Tian-Li Wang Wei-Bing Liao Yi-Han Wang Yuan Wu Yu-Zhen Yin Jie Pan Yi zhang Qing Wang Jian-Yang zhang Tao Yang Yasir Sohail Jin-Yu zhang Hua Ji Qiang Li Wei-Di Liu zhi-Gang Chen Xiong-Jun Liu Wen Ma Liang Mao Zhen-Duo Wu School of Materials science and Engineering Nanjing University of Science and Technology Jiangsu Key Laboratory for Advanced Metallic Materials School of Materials Science and Engineering Southeast University Department of Physics City University of Hong Kong School of Materials science and Engineering Tianjin University School of Physics and Microelectronics Zhengzhou University Department of Mechanical Engineering Research Institute for Advanced Manufacturing The Hong Kong Polytechnic University Center of Electron Microscopy and State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province) School of Materials Science and Engineering Dalian University of Technology Institute of Advanced Wear & Corrosion Resistance and Functional Materials Jinan University School of Mechanics and Civil Engineering China University of Mining and Technology School of Physical sciences Great Bay University School of Materials science andEngineering Harbin Institute of Technology State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical Engineering Nanjing Tech University beijing Advanced Innovation Center for Materials Genome Engineering Research Institute for Carbon Neutrality University of Science and Technology Beijing Department of Mechanical Engineering The University of Hong Kong School of Computing Macquarie University Key Laboratory of Optoelectronic Devices and systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen University State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing State Key Laboratory of Materials Processing and Die & Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Institute of materials Shanghai University Department of Materials science and Engineering C

Owing to their exceptional properties, high-entropy alloys(HEAs) and high-entropy materials have emerged as promising research areas and shown diverse applications. Here,the recent advances in the field are comprehensively reviewed,organized into five sections. The first section introduces the background of HEAs, covering their definition, significance,application prospects, basic properties, design principles, and microstructure. The subsequent section focuses on cutting-edge high-entropy structural materials, highlighting developments such as nanostructured alloys, grain boundary engineering,eutectic systems, cryogenic alloys, thin films, micro-nano-lattice structures, additive manufacturing, high entropy metallic glasses, nano-precipitate strengthened alloys, composition modulation, alloy fibers, and refractory systems. In the following section, the emphasis shifts to functional materials, exploring HEAs as catalysts, magneto-caloric materials, corrosion-resistant alloys, radiation-resistant alloys, hydrogen storage systems, and materials for biomedicine. Additionally, the review encompasses functional high-entropy materials outside the realm of alloys, including thermoelectric, quantum dots, nanooxide catalysts, energy storage materials, negative thermal expansion ceramics,and high-entropy wave absorption materials. The paper concludes with an outlook, discussing future directions and potential growth areas in the field. Through this comprehensive review,researchers, engineers, and scientists may gain valuable insights into the recent progress and opportunities for further exploration in the exciting domains of high-entropy alloys and functional materials.

关键词： Cutting-edge structural materials Cutting-edgefunctional materials High entropy alloys

The In-Flight Realtime Trigger and Localization Software of GECAM

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Research in Astronomy and Astrophysics 2024年第10期24卷 11-24页

作者： Xiao-Yun Zhao Shao-Lin Xiong Xiang-Yang Wen Xin-Qiao Li Ce Cai Shuo Xiao Qi Luo Wen-Xi Peng Dong-Ya Guo Zheng-Hua An Ke Gong Jin-Yuan Liao Yan-Qiu zhang Yue Huang Lu Li Xing Wen fei zhang Jing Duan Chen-Wei Wang Dong-Li Shi Peng zhang Qi-Bin Yi Chao-Yang Li Yan-Bing Xu Xiao-Hua Liang Ya-Qing Liu Da-Li zhang Xi-Lei Sun Fan zhang Gang Chen Huan-Yu Wang Sheng Yang Xiao-Jing Liu Min Gao Mao-Shun Li Jin-Zhou Wang Xing Zhou Yi Zhao Wang-Chen Xue Chao Zheng Jia-Cong Liu Xing-Bo Han Jin-Ling Qi Jia Huang Ke-Ke zhang Can Chen Xiong-Tao Yang Dong-Jie Hou Yu-Sa Wang Rui Qiao Xiang Ma Xiao-Bo Li ping Wang Xin-Ying Song Li-Ming Song Shi-Jie Zheng Bing Li Hong-Mei zhang Yue Zhu Wei Chen Jian-Jian He Zhen zhang Jin Hou Hong-Jun Wang Yan-Chao Hao Xiang-Yu Wang Zong-Yuan Yang zhi-Long Wen zhi Chang Yuan-Yuan Du Rui Gao Xiao-fei Lan Yan-Guo Li Gang Li Xu-Fang Li Fang-Jun Lu Hong Lu Bin Meng Feng Shi Hui Wang Hui-Zhen Wang Yu-Peng Xu Jia-Wei Yang Xue-Juan Yang Shuang-Nan zhang Chao-Yue zhang Cheng-Mo zhang zhi-Cheng Tang Cheng Cheng Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese academy of sciences Chinese Academy of SciencesBeijing 100049China School of Information science and Technology Southwest Jiaotong UniversityChengdu 611756China Key Laboratory of Stellar and Interstellar Physics and Department of Physics Xiangtan UniversityXiangtan 411105China Physics and Space science College China West Normal UniversityNanchong 637002China Department of Astronomy Beijing Normal UniversityBeijing 100875China Innovation academy for Microsatellites of CAS Shanghai 201203China Changchun University of science and Technology Changchun 130022China Chinese academy of sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China

Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2.2. December *** developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic *** onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation *** paper provides a detailed description of the design and development of the trigger and localization software system for *** covers the general design,workflow,the main functions,and the algorithms used in the *** paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation.

关键词： telescopes instrumentation:detectors methods:observational

Estimation of speed-related car body acceleration limits with quantile regression

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Railway sciences 2024年第5期3卷 575-592页

作者： Jianli Cong Hang zhang Zilong Wei fei Yang Zaitian Ke Tao Lu, Rong Chen {2. Wang Zili Li china academy of Railway {2. Corporation Limited Infrastructure Inspection Research InstituteBeijingChina School of Civil Engineering Beijing Jiaotong UniversityBeijingChina and Planning and Standard Research InstituteNational Railway AdministrationBeijingChina MOE Key Laboratory of High-Speed Railway Engineering Southwest Jiaotong UniversityChengduChina Department of Engineering Structures Delft University of TechnologyDelftNetherlands

Purpose–This study aimed to facilitate a rapid evaluation of track service status and vehicle ride comfort based on car body ***,a low-cost,data-driven approach was proposed for analyzing speed-related acceleration limits in metro ***/methodology/approach–A portable sensing terminal was developed to realize easy and efficient detection of car body ***,field measurements were performed on a 51.95-km metro *** from 2.2.metro sections were tested as a case study,and a quantile regression method was proposed to fit the control limits of the car body acceleration at different speeds using the measured ***–First,the frequency statistics of the measured data in the speed-acceleration dimension indicated that the car body acceleration was primarily concentrated within the constant speed stage,particularly at speeds of 15.4,18.3,and 2..9 m/***,resampling was performed according to the probability density distribution of car body acceleration for different speed domains to achieve data ***,combined with the traditional linear relationship between speed and acceleration,the statistical relationships between the speed and car body acceleration under different quantiles were *** concluded the lateral/vertical quantiles of 0.8989/0.9895,0.9942.0.997,and 0.9998/0.993 as being excellent,good,and qualified control limits,respectively,for the lateral and vertical acceleration of the car *** addition,regression lines for the speedrelated acceleration limits at other quantiles(0.5,0.75,2.,and 3s)were ***/value–The proposed method is expected to serve as a reference for further studies on speedrelated acceleration limits in rail transit systems.

关键词： Car body acceleration Track status monitoring Speed-related acceleration limit Quantile regression Vehicle ride quality

Microwave electrometry with Rydberg atoms in a vapor cell using microwave amplitude modulation

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Chinese Physics B 2024年第5期33卷 65-74页

作者：郝建海贾凤东崔越王昱寒周飞刘修彬张剑谢锋白金海尤建琦王宇钟志萍 School of Physical sciences University of Chinese Academy of SciencesBeijing 100049China Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China science and Technology on Metrology and Calibration Laboratory Changcheng Institute of Metrology & MeasurementAviation Industry Corporation of ChinaBeijing 100095China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

We have theoretically and experimentally studied the dispersive signal of the Rydberg atomic electromagneticallyinduced transparency(EIT)Autler–Townes(AT)splitting spectra obtained using amplitude modulation of the microwave(MW)electric *** addition to the two zero-crossing points interval△f_(zeros),the dispersion signal has two positive maxima with an interval defined as the shoulder interval△f_(sho),which is theoretically expected to be used to measure a much weaker MW electric *** relationship of the MW field strength E_(MW)and△f_(sho)is experimentally studied at the MW frequencies of 31.6 GHz and 9.2.GHz *** results show that△f_(sho)can be used to characterize the much weaker E_(MW)than that of△f_(zeros)and the traditional EIT–AT splitting interval△f_(m);the minimum E_(MW)measured by△f_(sho)is about 30 times smaller than that by△f_(m).As an example,the minimum E_(MW)at 9.2.GHz that can be characterized by△f_(sho)is 0.056 mV/cm,which is the minimum value characterized by the frequency interval using a vapor cell without adding any auxiliary *** proposed method can improve the weak limit and sensitivity of E_(MW)measured by the spectral frequency interval,which is important in the direct measurement of weak E_(MW).

关键词： quantum sensor Rydberg atoms electromagnetically induced transparency amplitude modulation

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篇章级文本的事件图谱构建与事件抽取方法

计算机工程与设计 2024年第1期45卷 146-152页

作者：张源奔赵一斐赵志浩韩众和张利利谢辉平中国科学院空天信息创新研究院北京100190 中国科学院网络信息体系技术重点实验室北京100190 中国科学院齐鲁空天信息研究院山东济南250000 北京化工大学信息科学与技术学院北京100029

针对篇章级事件抽取任务主要存在的以下3个挑战:模型复杂、事件论元分散以及多事件抽取,提出一种基于异质交互图和有序树的篇章级事件抽取方法DTHIGN。支持以解耦实体抽取部分的方式精简模型的参数;构建面向触发词的篇章级异质交互图,... 详细信息

针对篇章级事件抽取任务主要存在的以下3个挑战:模型复杂、事件论元分散以及多事件抽取,提出一种基于异质交互图和有序树的篇章级事件抽取方法DTHIGN。支持以解耦实体抽取部分的方式精简模型的参数;构建面向触发词的篇章级异质交互图,更全面地对语义进行建模;支持使用基于统一事件模板的树形事件论元抽取方式获得事件论元结果。实验结果表明,该方法能够获得较好的效果并显著降低模型的训练难度。

关键词：深度学习自然语言处理事件图谱事件抽取事件论元抽取异质图图卷积网络