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Impact of climate change on food security in the Central Asian countries

Science China Earth Sciences 2024年第1期67卷 268-280页

作者： Fang SU Yu LIU Lvfan CHEN Rustam OROZBAEV liangcheng tan School of Economics and Management Northwest UniversityXi’an 710127China School of Economics and Management Shaanxi University of Science and TechnologyXi’an 710021China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Institute of Geology National Academy of Sciences of Kyrgyz RepublicBishkek 720040Kyrgyzstan Institute of Global Environmental Change Xi’an Jiaotong UniversityXi’an 710049China

The current and potential impacts of global warming have generated widespread concerns about food security among all sectors of *** Asian countries located deep in the interior of Asia with fragile ecological environments and lower agricultural technology are particularly more prone to severe threats from climate *** on panel data acquired in five Central Asian countries from 1990 to 2019,a C-D-C model was developed to study how climate change affects food security in the region and to predict future *** study found that the level of food security has generally increased for these five Central Asian countries over the past 30 years,with Kazakhstan and Tajikistan having the highest and lowest food security levels,*** average annual temperature and precipitation exhibit an inverted U-shaped relationship with the region’s food security,with the most positive effect on the food security of *** high and low temperatures have significantly affected food security in the studied region,with Turkmenistan experiencing the most significant negative *** number of frost days had no significant effect on food *** analysis of future climate showed that the temperature and precipitation in Central Asia will continue to increase from 2030 to 2090,which will negatively impact the food security of these *** is recommended that the Central Asian countries enhance their understanding of climate risks,strengthen scientific climate research,and develop multiple adaptation strategies in ***,they are encouraged to consolidate international cooperation,reducing greenhouse gas emissions effectively and maintaining the ability to ensure food security.

关键词： Global warming Extreme climate Food security Future forecasts Five Central Asian countries

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水下航行器自主导航定位技术前沿进展

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兵器装备工程学报 2024年第3期45卷 161-171页

作者：张淋谭良成重庆交通大学航运与船舶工程学院重庆400074

导航与定位技术是自主水下航行器(AUV)预设任务并安全返航的前提,由于水下环境的限制,目前广泛采用多系统组合导航的方式来实现AUV的准确定位。面向AUV的工况特点,详细介绍了水声测速系统、水声定位系统以及地球物理场辅助导航技术的特... 详细信息

导航与定位技术是自主水下航行器(AUV)预设任务并安全返航的前提,由于水下环境的限制,目前广泛采用多系统组合导航的方式来实现AUV的准确定位。面向AUV的工况特点,详细介绍了水声测速系统、水声定位系统以及地球物理场辅助导航技术的特征与技术难点,分析了用于水下自主导航时多源组合导航方法的最新进展,随着相关测量仪器领域的研究进展,基于精确测量地球物理场特征的辅助导航技术成为具有极强竞争力的方案之一。多AUV协同导航方案同样适用于复杂的水下环境,被视为未来AUV导航技术重要发展方向。

关键词：自主水下航行器组合导航水下声学系统协同导航辅助导航

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Mid-Holocene Climate Variations Recorded by Palaeolake in Marginal Area of East Asian Monsoon: A Multi-proxy Study

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Chinese Geographical Science 2007年第4期17卷 325-332页

作者： LONG Hao tan Hongbin WANG Naiang tan liangcheng LI Yu Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China School of Resources and Environment Lanzhou University Lanzhou 730000 China State Key Laboratory of Loess and Quaternary Geology Instttute of Earth Environment Chinese Academy of Sciences Xi＇an 710075 China

Traditionally, the mid-Holocene in most parts of China was thought to be warmer with higher precipitation, resulting from a strong Asian summer monsoon. However, some recent researches have proposed a mid-Holocene drought interval of millennial-scale in East Asian monsoon margin areas. Thus whether mid-Holocene was dry or humid remains an open issue. Here, Zhuyeze palaeolake, the terminal lake of the Shiyang River Drainage lying in Asian monsoon marginal areas, was selected for reconstructing the details of climate variations during the Holocene, especially mid-Holocene, on the basis of a sedimentological analysis. Qingtu Lake (QTL) section of 6.92m depth was taken from Zhuyeze palaeolake. Multi-proxy analysis of QTL section, including grain size, carbonate, TOC, C/N and δ13C of organic matter, was used to document regional climatic changes during 9-3 cal ka B.P. The record shows a major environmental change at 9.0-7.8 cal ka B.P., attributed to a climate trend towards warmth and humidity. This event was followed by a typical regional drought event which occurred during 7.8-7.5 cal ka B.P. And a warm and humid climate prevailed from 7.5 to 5.0 cal ka B.P., attributed to the warm/humid Holocene Optimum in this region. After that, the climate gradually became drier. Moreover, comparison of the climate record from this paper with the summer insolation at 30°N indicates that the climate pattern reflecting the Asian monsoon changes was caused by insolation change.

关键词：湖泊沉积物气候变化东亚季风区域气候学

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Improved Proximal Policy Optimization Algorithm for Sequential Security-constrained Optimal Power Flow Based on Expert Knowledge and Safety Layer

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 742-753页

作者： Yanbo Chen Qintao Du Honghai Liu liangcheng Cheng Muhammad Shahzad Younis State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources and School of Electrical&Electronic Engineering North China Electric Power UniversityBeijing 102206China School of Engineering Xining UniversityXining 810008Chinaand Key Laboratory of Smart Operation of New Energy Power SystemMinistry of EducationQinghai UniversityXining 810016China China Electric Power Research Institute Nanjing 210003China National University of Sciences and Technology Islamabad44000Pakistan

In recent years,reinforcement learning(RL)has emerged as a solution for model-free dynamic programming problem that cannot be effectively solved by traditional optimization *** has gradually been applied in the fields such as economic dispatch of power systems due to its strong selflearning and self-optimizing ***,existing economic scheduling methods based on RL ignore security risks that the agent may bring during exploration,which poses a risk of issuing instructions that threaten the safe operation of power ***,we propose an improved proximal policy optimization algorithm for sequential security-constrained optimal power flow(SCOPF)based on expert knowledge and safety layer to determine active power dispatch strategy,voltage optimization scheme of the units,and charging/discharging dispatch of energy storage *** expert experience is introduced to improve the ability to enforce constraints such as power balance in training process while guiding agent to effectively improve the utilization rate of renewable ***,to avoid line overload,we add a safety layer at the end of the policy network by introducing transmission constraints to avoid dangerous actions and tackle sequential SCOPF *** results on an improved IEEE 118-bus system verify the effectiveness of the proposed algorithm.

关键词： Sequential security-constrained optimal power flow(SCOPF) expert experience safety layer renewable energy safe reinforcement learning

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Aeolian dust dynamics in the Fergana Valley, Central Asia, since -30 ka inferred from loess deposits

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Geoscience Frontiers 2021年第5期12卷 93-109页

作者： Yue Li Yougui Song Dimitris G.Kaskaoutis Jinbo Zan Rustam Orozbaev liangcheng tan Xiuling Chen State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China Institute for Environmental Research and Sustainable Development National Observatory of AthensAthens 11810Greece Environmental Chemical Processes Laboratory Department of ChemistryUniversity of CreteCrete 71003Greece Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Institute of Geology National Academy of Sciences of Kyrgyz RepublicBishkek 720040Kyrgyzstan Research Center for Ecology and Environment of Central Asia(Bishkek) Bishkek 720040Kyrgyzstan Institute of Geography Fujian Normal UniversityFuzhou 350007China State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province Fujian Normal UniversityFuzhou 350007China

Knowledge of the interactions among atmospheric dynamics,dust emissions and climate system is essential to understand the physical mechanisms for the dust lifecycle,their role in loess formation as well as the predictions of future dust ***,these issues still remain relatively poorly known in Central Asia(CA).The extensive loess deposits on the CA pediments provide a promising archive to explore atmospheric dust dynamics and climatic conditions in the past and their association with loess *** study investigates the granulometric and magnetic properties of a loess section(named Osh section)in the Fergana Valley,which provides a sensitive record of atmospheric dust dynamics since 30 ka based on radiometric(AMS ^(14)C)*** frequency-dependent magnetic susceptibility(χfd)and the mean grain size are used to reconstruct the broadscale effective moisture and summer atmospheric dynamics pattern in CA,*** results show that the precession forcing exerts a huge influence on the wind-regime variabilities in CA,but with different physical processes under the impact of the Northern Hemisphere ice sheet(NHIS)before and after 15 *** origin of the sedimentation rate variations in the Osh loess is also linked to the NHIS-modulated changes of the atmospheric circulation *** the strengthened westerlies or the increased surface roughness from higher vegetation cover in loess-deposition areas have significantly accelerated the loess *** a result,these complicated influence factors of sedimentation rate change in the Osh loess section,especially during the Holocene epoch,may hamper accessibility of the authentic dust emission flux and atmospheric dust concentration in CA.

关键词： Dust dynamics Climate Atmospheric patterns Loess Ice volume Fergana Valley

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Great flood in the middle-lower Yellow River reaches at 4000 a BP inferred from accurately-dated stalagmite records

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Science Bulletin 2018年第4期63卷 206-208页

作者： liangcheng tan Chuan-Chou Shen Yanjun Cai Hai Cheng R.Lawrence Edwards State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Open Studio for Oceanic-Continental Climate and Environment Changes Qingdao National Laboratory for Marine Science and Technology Institute of Global Environmental Change Xi’an Jiaotong University High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC) Department of Geosciences Taiwan University Department of Earth Sciences University of Minnesota

Recently,Wu et al.[1]suggested an earthquake-induced landslide dam outburst flood on the eastern Tibetan Plateau at 1920BCE(3870 a BP,BP denotes year before 1950 CE)caused the Great Flood in the middle-lower Yellow River reaches,and resulted in the founding of Xia Dynasty at 3850 a *** age is$150–300younger than the previously estimated age of the Xia Dynasty[2].While the geological evidence of the outburst flood。

关键词：石笋记录活动范围大洪水 BP 黄河黄土高原 BCE 幻灯片

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The selection of a primary marker for the Anthropocene

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Science Bulletin 2019年第22期64卷 1643-1645页

作者： Tianli Wang liangcheng tan Hai Xu Jingjie Zang Dong Li Jianghu Lan Yongming Han Li Li State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi'an 710061China Institute of Global Environment Change Xi'an Jiaotong UniversityXi'an 710049China Open Studio for Oceanic-Continental Climate and Environment Changes Qingdao Pilot National Laboratory for Marine Science and TechnologyQingdao 266061China institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China

Since Homo sapiens appeared,the planet has experienced continuing environmental changes[1,2].In 2000,Crutzen and Stoermer[3]systematically analysed the global changes caused by human activity over the previous 300 years and suggested that the Holocene epoch ended in the 1750s and a new geological age,the Anthropocene,***,the Anthropocene drew a lot of attention from both scientific community and the general *** recognition and placement of the Anthropocene/Holocene boundary has been a subject of heated debates over the past two *** the 35th International Geological Congress(2016;IGC),the Anthropocene Working Group(AWG)recommended the Anthropocene to be formalised with an epoch rank,with the 1950s as its lower boundary[4].

关键词： Holocene epoch boundary

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Nitrogen incorporated oxygen vacancy enriched MnCo_(2)O_(x)/BiVO_(4) photoanodes for efficient and stable photoelectrochemical water splitting

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Nano Research 2024年第3期17卷 1140-1150页

作者： liangcheng Xu Yingjuan Zhang Boyan Liu Xin Wang Gangqiang Zhu Lianzhou Wang Songcan Wang Wei Huang Frontiers Science Center for Flexible Electronics Xi’an Institute of Flexible Electronics(IFE)Northwestern Polytechnical University127 West Youyi RoadXi’an 710072China School of Physics and Information Technology Shaanxi Normal UniversityXi’an 710062China Nanomaterials Centre Australian Institute for Bioengineering and Nanotechnology and School of Chemical EngineeringThe University of QueenslandBrisbaneQueensland 4072Australia Research&Development Institute of Northwestern Polytechnical University in Shenzhen Sanhang Science&Technology BuildingNo.45thGaoxin South 9th RoadNanshan DistrictShenzhen 518063China

Oxygen vacancies in oxygen evolution cocatalysts(OECs)can significantly improve the photoelectrochemical(PEC)water splitting performance of ***,OECs with abundant oxygen vacancies have a poor stability when exposing to the highly-oxidizing photogenerated ***,we partly fill oxygen vacancies in a MnCo_(2)O_(x) OEC with N atoms by a combined electrodeposition and sol-gel method,which dramatically improves both photocurrent density and stability of a BiVO_(4) *** optimized N filled oxygen vacancy-rich MnCo_(2)O_(x)/BiVO_(4) photoanode(3 at.%of N)exhibits an outstanding photocurrent density of 6.5 mA·cm^(-2) at 1.23 VRHE under AM 1.5 G illumination(100 mW·cm^(-2)),and an excellent stability of over 150 *** characterizations and theoretical calculations demonstrate that N atoms stabilize the defect structure and modulate the surface electron distribution,which significantly enhances the stability and further increases the photocurrent ***,other heteroatoms such as carbon,phosphorus,and sulfur are confirmed to have similar effects on improving PEC water splitting performance of photoanodes.

关键词： water splitting oxygen evolution bismuth vanadate(BiVO_(4)) filling oxygen vacancies cocatalysts

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上新世以来南极底层水变化及其与全球气候的潜在联系

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科学通报 2023年第20期68卷 2583-2585页

作者：易亮谭亮成姚会强邓成龙同济大学海洋地质国家重点实验室上海200092 中国科学院地球环境研究所黄土与第四纪地质国家重点实验室西安710061 西安交通大学全球环境变化研究院西安710049 中国地质调查局广州海洋地质调查局自然资源部海底矿产资源重点实验室广州510075 南方海洋科学与工程广东省实验室(广州) 广州511458 中国科学院地质与地球物理研究所岩石圈演化国家重点实验室北京100029 中国科学院大学地球与行星科学学院北京101408

2004年上映了福克斯公司制作的科幻片《后天》(The Day After Tomorrow),主要讲述温室效应造成大洋环流异动、地球重新来到冰河纪的故事.近年来不断有证据表明,大洋环流在全球变暖背景下已经进入了一个显著变弱的阶段[1].预测这种环流... 详细信息

2004年上映了福克斯公司制作的科幻片《后天》(The Day After Tomorrow),主要讲述温室效应造成大洋环流异动、地球重新来到冰河纪的故事.近年来不断有证据表明,大洋环流在全球变暖背景下已经进入了一个显著变弱的阶段[1].预测这种环流减弱是否如“后天”猜测的那般,需要对过去大洋环流的变化进行重建.

关键词：大洋环流全球气候南极底层水上新世全球变暖温室效应科幻片潜在联系

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Dust storms in northern China during the last 500 years

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Science China Earth Sciences 2021年第5期64卷 813-824页

作者： Shuang ZHANG Hai XU Jianghu LAN Yonaton GOLDSMITH Adi TORFSTEIN Guilin ZHANG Jin ZHANG Yunping SONG Kang’en ZHOU liangcheng tan Sheng XU Xiaomei XU Yehouda ENZEL Institute of Surface-Earth System Science School of Earth System ScienceTianjin UniversityTianjin 300072China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China Institute of Earth Sciences the Hebrew University of JerusalemJerusalem 91904Israel Department of Earth System Science University of CaliforniaIrvineCA 92697USA

The history and mechanisms of dust storms in northern China remain unclear owing to the paucity of reliable longterm,high-resolution geological *** this study,we reconstructed the dust storm history of the last~500 years in northern China,based on sedimentary coarse fraction(>63μm)of a well-dated core from Lake Daihai,Inner *** highresolution data reveal three intervals of frequent dust storms:AD 1520–1580,AD 1610–1720,and AD 1870–*** dust storm events in the Lake Daihai area were broadly synchronous with those inferred from other historical or geological records and generally occurred during cold *** in the intensity of Siberian High and the westerlies modulated by temperature variations are the likely major factors controlling dust storm *** interesting feature is that although the intensities of dust storms have been systematically increased during the recent warming period,a clear decreasing trend within this period is *** recent increase in average dust storm intensity may be ascribed to an increase in particle supply resulting from a rapid increase in human activity,whereas the weakening trend was likely caused by decreases in average wind speed resulting from the recent global warming.

关键词： Dust storm Lake Daihai Temperature Wind speed Human activity

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