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Human disturbance exacerbated erosion and deposition in the karst peak-cluster depressions during the Ming and Qing dynasties

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Science China Earth sciences 2024年第11期67卷 3550-3561页

作者： Shuai YUAN Yuemin YUE Xinbao ZHANG Lu WANG Lu ZHAI Kelin WANG Key Laboratory for Agro-Ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of Sciences University of chinese academy of sciences Institute of Mountain Hazards and Environment Ministry of Water Resources Chinese Academy of Sciences State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences

Under the background of large-scale ecological restoration, China's southwestern karst region has become a hotspot of global vegetation cover “greening” in the past 20 years. However, because of geological constraints, it is difficult to restore the forest landscapes in some areas. It is urgent to understand the impacts of human disturbances during the historical period on the difficult-to-forestation rocky-desertification areas of the karst region in order to guide future afforestation. In this study, we quantified the changes of specific sediment yield in typical karst depressions over the past 500 years by using137Cs,210Pb, and14C dating methods in karst depressions, and identified the main human disturbances related to historical erosion and sedimentation by combining with historical data. The results showed that the erosion and sedimentation of the three depressions in 1921–1963 were significantly higher than that in 1963–2021, and the sedimentation rate(0.64–1.33 cm a-1) and the specific sediment yield(2.51–13.11 t ha-1a-1) during Ming and Qing dynasties（1504–1812） were higher than the sedimentation rate(0.26–0.95 cm a-1) and specific sediment yield(0.95–6.99 t ha-1a-1) in the recent century（1921–2021）. Reconstruction data and literature from the Ming and Qing dynasties show an empirical link between changes in population, arable land, food, forest area,and deforestation events during the same period. It was found that the population and arable land in Guangxi increased more than three-fold and the forest area decreased significantly in the 17th century after the migration of the Yao ethnic group and the introduction of maize to the region, which may be the main reason for intensifying the erosion of depressions. This study is of great significance to understanding the evolution history of rocky desertification in this region and to answer the potential of afforestation.

关键词： Karst region 14C dating Peak-cluster depressions Ethnic minirity migration Specific sediment yield

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A Disulfide-Based Poly(ether-b-amide)Copolymer with Rapid Self-healing Ability under Moderate Conditions

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chinese Journal of Chemistry 2024年第9期42卷 943-950页

作者： Weijan Lu ping Zhu Ying Zhao Dujin Wang Xia Dong Institute of Chemistry Chinese Academy of SciencesBeijing 100190China Schoolof Chemical sciences University of Chinese Academy of SciencesBeijing 100049China

Comprehensive Summary A disulfide-based poly(ether-b-amide)copolymer with rapid self-healing capability under moderate conditions was synthesized from 4,4’-dithiodibutyric acid(DTDBA),isophorondiamine(IPDA)and poly(tetramethylene oxide)(PTMO)based on a two-step *** incorporation of IPDA with asymmetric structure and substantial steric hindrance not only effectively decreased the number of regular H-bonds,but also inhibited the crystallization of polyamide segments,imparting the synthesized poly(ether-b-amide)copolymer with an amorphous structural *** on the coordination of segmental diffusion and recombination of disulfide bonds and hydrogen bonds,the scratches and damaged mechanical properties of PEBADS-I611 could be completely self-healed after healing at 40°C for only 11 min and 3 h,respectively.

关键词： Poly(ether-b-amide)copolymer Disulfide bonds Hydrogen bonds Polycondensation Smart polymers Self-healing

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Audio-guided self-supervised learning for disentangled visual speech representations

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Frontiers of Computer Science 2024年第6期18卷 186353-186353页

作者： FENG Dalu YANG Shuang SHAN Shiguang CHEN Xilin Key Laboratory of Intelligent Information Processing of chinese academy of sciences Institute of Computing Technology chinese academy of sciences University of chinese academy of sciences

In this paper, we propose a novel two-branch framework to learn the disentangled visual speech representations based on two particular observations. Its main idea is to introduce the audio signal to guide the learning of speech-relevant cues and introduce a bottleneck to restrict the speech-irrelevant branch from learning high-frequency and fine-grained speech cues. Experiments on both the word-level and sentence-level audio-visual speech datasets LRW and LRS2-BBC show the effectiveness. Our future work is to explore more explicit auxiliary tasks and constraints beyond the reconstruction task of the speech-relevant and irrelevant branch to improve further its ability of capturing speech cues in the video. Meanwhile, it’s also a nice try to combine multiple types of knowledge representations [10] to further boost the obtained speech epresentations, which is also left for the future work.

关键词： Knowledge representation

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Assessments of Data-Driven Deep Learning Models on One-Month Predictions of Pan-Arctic Sea Ice Thickness

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Advances in Atmospheric sciences 2024年第7期41卷 1379-1390页

作者： Chentao SONG Jiang ZHU Xichen LI Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China University of chinese academy of sciences Beijing 100049China

In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,mainly due to the limited time coverage of observations and reanalysis ***,deep learning predictions of sea ice thickness(SIT)have yet to receive ample *** this study,two data-driven deep learning(DL)models are built based on the ConvLSTM and fully convolutional U-net(FC-Unet)algorithms and trained using CMIP6 historical simulations for transfer learning and fine-tuned using reanalysis/*** models enable monthly predictions of Arctic SIT without considering the complex physical processes *** comprehensive assessments of prediction skills by season and region,the results suggest that using a broader set of CMIP6 data for transfer learning,as well as incorporating multiple climate variables as predictors,contribute to better prediction results,although both DL models can effectively predict the spatiotemporal features of SIT *** the predicted SIT anomalies of the FC-Unet model,the spatial correlations with reanalysis reach an average level of 89%over all months,while the temporal anomaly correlation coefficients are close to unity in most *** models also demonstrate robust performances in predicting SIT and SIE during extreme *** effectiveness and reliability of the proposed deep transfer learning models in predicting Arctic SIT can facilitate more accurate pan-Arctic predictions,aiding climate change research and real-time business applications.

关键词： Arctic sea ice thickness deep learning spatiotemporal sequence prediction transfer learning

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Context‑dependent antioxidant defense system(ADS)‑based stress memory in response to recurrent environmental challenges in congeneric invasive species

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Marine Life Science & Technology 2024年第2期6卷 315-330页

作者： Hanxi Li Xuena Huang Aibin Zhan Research Center for Eco-Environmental sciences Chinese Academy of SciencesBeijing 100085China University of chinese academy of sciences Beijing 100049China

Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine *** withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their ***,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental *** we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and *** results demonstrated that *** exhibited higher tolerance and resistance to salinity stresses at the physiological level,while *** demonstrated heightened responses at the transcriptional *** observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)*** Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only *** demonstrated transcriptional stress *** regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona *** findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental *** results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.

关键词： Antioxidant defense Ascidian Biological invasion Environmental stress Stress memory

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What can we learn from recent 2νββexperiments?

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chinese Physics C 2024年第3期48卷 93-103页

作者：房栋梁 Institute of Modern Physics Chinese Academy of sciencesLanzhou 730000China University of chinese academy of sciences Beijing 100049China

Recent measurements of the two neutrino double beta decay high precision electron spectra,combined with charge exchange orβ-decay experimental data,have revealed severe constraints across current nuclear many body *** calculations show that the quasi-particle random phase approximation(QRPA)approach can adequately reproduce the measured spectra for the two open shell nuclei,^(82)Se and ^(100)*** the closed shell nucleus ^(136)Xe,QRPA can also reproduce the spectra with proper *** the high-lying state reduction,we also find that the nuclear shell model can also adequately reproduce the spectra and Gamow-Teller transition strength under a unique quenched axial-vector coupling constant *** ^(136)Xe,we find that flipping the sign for the decay strength causes the spectra to go beyond the so-called high-lying state dominance *** results call for future high precision measurements of charge-exchange reactions.

关键词： nuclear stucture double beta decay electron spectra

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Space advanced technology demonstration satellite

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Science China(Technological sciences) 2024年第1期67卷 240-258页

作者： ZHANG XiaoFeng CHEN Wen ZHU XiaoCheng MENG Na HE JunWang BI XingZi ZHANG YongHe SHI Qi LI Fei LIU Rui FENG ZhengGong LIU Liu LI JinSong WU HaiChen XU DongXiao LI TaiJie HUANG JiangJiang LIU Shuo LI TianTong YU XianSheng GAO Yang ZHOU Heng BAN HanYu ZHANG YanLi ZHANG YueTing YANG YingQuan HE Tao DUAN XuLiang CHEN Xin WANG YaMin SUN AnTai ZHANG KuoXiang SUN Ying WANG YaoBin FAN ChengCheng XIONG ShaoLin LI XinQiao WEN XiangYang LING ZhiXing SUN XiaoJin ZHANG Chen BAI XianYong WANG ZhanShan DENG YuanYong TIAN Hui YANG JianFeng XUE HongBo SANG Peng LIU JinGuo ZHENG HuiLong ZHU Xiang HE JianWu LI Hui XU LuXiang XU ShuYan CHEN WenWu LIU ZhenDong WANG ZhaoLi MAO XiangLong GAO Rong LI ZongXuan DING GuoPeng WANG XinYu DOU RunJiang WENG LuBin LUO Hao WANG YaPing LIANG XianFeng FANG ZiRuo Innovation academy for Microsatellites Chinese Academy of SciencesShanghai 201203China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China National Astronomical Observatory of China Beijing 100101China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China Institute of Precision Optical Engineering School of Physics Science and EngineeringTongji UniversityShanghai 200092China School of Earth and Space sciences Peking UniversityBeijing 100871China Xi’an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi’an 710119China National Space Science Center Chinese Academy of SciencesBeijing 100190China Shenyang Institute of Automation Chinese Academy of SciencesShenyang 110016China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China Shanghai Institute of Organic Chemistry Chinese Academy of SciencesShanghai 200032China Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310024China Nanyang Technological University Singapore 569830Singapore Dalian Institute of Chemical Physics Chinese Academy of SciencesDalian 116023China Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100049China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China Institute of Automation Chinese Academy of SciencesBeijing 100190China School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310058China

The Space Advanced Technology demonstration satellite(SATech-01),a mission for low-cost space science and new technology experiments,organized by chinese academy of sciences(CAS),was successfully launched into a Sun-synchronous orbit at an altitude of~500 km on July 27,2022,from the Jiuquan Satellite Launch *** as an experimental platform for space science exploration and the demonstration of advanced common technologies in orbit,SATech-01 is equipped with 16 experimental payloads,including the solar upper transition region imager(SUTRI),the lobster eye imager for astronomy(LEIA),the high energy burst searcher(HEBS),and a High Precision Magnetic Field Measurement System based on a CPT Magnetometer(CPT).It also incorporates an imager with freeform optics,an integrated thermal imaging sensor,and a multi-functional integrated imager,*** paper provides an overview of SATech-01,including a technical description of the satellite and its scientific payloads,along with their on-orbit performance.

关键词： SATech-01 spacecraft design scientific instruments on-orbit performance

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A real-time calibration method based on time-to-digital converter for accelerator timing system

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Nuclear Science and Techniques 2024年第9期35卷 127-140页

作者： Qi-Hao Duan Liang Ge Yan-Hao Jia Jie-Yu Zhu Wei Zhang Institute of modern physics Chinese Academy of SciencesLanzhou 730000China University of chinese academy of sciences Beijing 100049China

The high-intensity heavy-ion accelerator facility(HIAF)is a scientific research facility complex composed of multiple cas-cade accelerators of different types,which pose a scheduling problem for devices distributed over a certain range of 2 km,involving over a hundred *** white rabbit,a technology-enhancing Gigabit Ethernet,has shown the capability of scheduling distributed timing devices but still faces the challenge of obtaining real-time synchronization calibration param-eters with high *** study presents a calibration system based on a time-to-digital converter implemented on an ARM-based System-on-Chip(SoC).The system consists of four multi-sample delay lines,a bubble-proof encoder,an edge controller for managing data from different channels,and a highly effective calibration module that benefits from the SoC *** performance was evaluated with an average RMS precision of 5.51 ps by measuring the time intervals from 0 to 24,000 ps with 120,000 data for every *** design presented in this study refines the calibration precision of the HIAF timing *** eliminates the errors caused by manual calibration without efficiency loss and provides data support for fault *** can also be easily tailored or ported to other devices for specific applications and provides more space for developing timing systems for particle accelerators,such as white rabbits on HIAF.

关键词： HIAF White rabbit Calibration system Time-to-digital converter(TDC)

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Density peak clustering using tensor network

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Science China(Information sciences) 2024年第3期67卷 321-322页

作者： Xiao SHI Yun SHANG Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical sciences University of Chinese Academy of Sciences National Center for Mathematics and Interdisciplinary sciences Key Laboratory of ManagementDecision and Information SystemsAcademy of Mathematics and Systems ScienceChinese Academy of Sciences

Tensor networks have been a powerful tool in simulating many-body physics and have recently gained recognition in the machine learning community due to their remarkable representation capabilities. However, using tens... 详细信息

关键词： Tensors

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Underwater RGB-D imaging system with millimetric precision

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Science China(Information sciences) 2024年第10期67卷 383-385页

作者： Yajun GAO Yang CONG Xu TANG Mingxue LI State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences University of chinese academy of sciences College of Automation Science and Engineering South China University of Technology

In recent years, underwater fine three-dimensional reconstruction technology has emerged as a focal point in research, exhibiting extensive potential applications, particularly in underwater archaeology and resource e... 详细信息

关键词： SINGLE CAMERA

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