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Plant phenology changes and drivers on the Qinghai-Tibetan Plateau (Jul, 10.1038/s43017-022-00317-5, 2022)

NATURE REVIEWS EARTH & ENVIRONMENT 2022年第10期3卷 717-717页

作者： Shen, Miaogen Wang, Shiping Jiang, Nan Sun, Jianping Cao, Ruyin Ling, Xiaofang Fang, Bo Zhang, Lei Zhang, Lihao Xu, Xiyan Lv, Wangwang Li, Baolin Sun, Qingling Meng, Fandong Jiang, Yuhao Dorji, Tsechoe Fu, Yongshuo Iler, Amy Vitasse, Yann Steltzer, Heidi Ji, Zhenming Zhao, Wenwu Piao, Shilong Fu, Bojie State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical Science Beijing Normal University Beijing China State Key Laboratory of Tibetan Plateau Earth System Resources and Environment (TPESRE) Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China School of Resources and Environment University of Electronic Science and Technology of China Chengdu China Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China School of Atmospheric Sciences Sun Yat-sen University Zhuhai China Department of Ecology College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of the Ministry of Education Peking University Beijing China Academy of Forest Inventory and Planning National Forestry and Grassland Administration Beijing China College of Water Sciences Beijing Normal University Beijing China Rocky Mountain Biological Laboratory Crested Butte CO USA Forest Dynamics Unit Swiss Federal Institute for Forest Snow and Landscape Research (WSL) Birmensdorf Switzerland Environment & Sustainability Department Fort Lewis College Durango CO USA

The ongoing phenological changes in vegetation on the Qinghai–Tibetan Plateau could modify land surface and atmospheric processes. In this Review, we summarize these changes, their drivers and the resulting impacts. The start of the growing season advanced by 9.4 ± 2.2 days during 1982–1999 and 8.3 ± 2.0 days over 2000–2020, and the end of season delayed by 8.2 ± 1.9 days during 2000–2020. The main identified drivers of these changes are warming temperatures and increasing precipitation, but their impacts vary substantially across the Qinghai–Tibetan Plateau. Other factors, such as grazing and nitrogen deposition, also potentially influence phenological changes, but these relationships are poorly constrained. In manipulation experiments, grazing and nitrogen addition have no individual effects on most phenophase timings at the population level, but nitrogen addition markedly delays flowering. Additionally, there are carry-over effects between phenophases that control subsequent temperature and precipitation responses. Phenological changes in turn could alter species interactions, modulate carbon and water cycling, and affect Asian monsoons and spring rainfall over eastern China, but evidence of these interactions is limited. Harmonization of remote-sensing-based and in situ observations, and simultaneous testing of both biotic and abiotic factors, are needed for a mechanistic understanding of Qinghai–Tibetan Plateau phenology dynamics.

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Absorption Bias: An Ideal Descriptor for Radiation Tolerance of Polycrystalline Bcc Metals

SSRN

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SSRN 2024年

作者： Wei, Liuming Zhao, Zhe Li, Yonggang Zheng, Qirong Zhang, Chuanguo Li, Jingyu Zhao, Gaofeng Da, Bo Zeng, Zhi Key Laboratory of Materials Physics Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei230031 China University of Science and Technology of China Hefei230026 China Department of Physics Henan Police College Zhengzhou450046 China Institute for Computational Materials Science School of Physics and Electronics Henan University Kaifeng475004 China Research and Services Division of Materials Data and Integrated System National Institute for Materials Science Namiki 1-1 Ibaraki Tsukuba305-0044 Japan

To evaluate the radiation tolerance of polycrystalline materials, the damage effects of Fe and W as typical body-centered cubic metals under uniform irradiation are studied by multi-scale models. An ideal descriptor, the absorption bias (the ratio of the absorption abilities of grain boundaries (GBs) to interstitials (I) and vacancies (V)), is proposed to reflect the radiation tolerance of metals with different grain sizes. Low absorption bias promotes defects annihilation through enhancing I-V recombination and optimally tuning its competition with GB absorption. Polycrystalline metals possess high anti-irradiation performance only with low absorption bias regulated by grain size and temperature. Furthermore, by comprehensively considering the mechanical property, thermal stability, and radiation tolerance described by absorption bias, nano-crystals are recommended for Fe-based structural materials but coarsegrained crystals for W-based plasma-facing materials. This work reevaluates the radiation tolerance of polycrystalline metals, resulting in new strategies for designing structural materials of nuclear devices through manipulating grain sizes. © 2024, The Authors. All rights reserved.

关键词： Polycrystalline materials

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Determining Feasible Region of Tie-line Transmission Considering Power Loss

Determining Feasible Region of Tie-line Transmission Conside...

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Electrical Engineering and Automation (IFEEA), International Forum on

作者： Qian Zhou Xuan Fan Juelin Liu Lili Wen Fan Mu Gaofeng Yang Wen Jiang State Grid Chongqing Electric Power Company Chongqing China State Grid Chongqing Economic Research Institute Chongqing China State Key Laboratory of Power Transmission Equipment & System Security and New Technology College of Electrical Engineering Chongqing University Chongqing China

Power supply is geographically located in the opposite direction of power demand in China. Consequently, tie-line power exchanges in interconnected power grids are common. A good description of the feasible region of tie-line transmission can improve utilization efficiency of power resources. In this paper, one two-stage determination method for the feasible region of tie-line power transmission with power loss is presented. Furthermore, in order to reduce the number of optimization in our two-stage method, an acceleration strategy is further presented based on hot-start operation point. The validation and effectiveness of the presented methods are demonstrated in the IEEE 14-bus and IEEE 300-bus test systems.

关键词： Electrical engineering Power demand Automation Power transmission Propagation losses Power grids Optimization

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Determining Feasible Region of Tie-line Transmission Considering Converter Station

Determining Feasible Region of Tie-line Transmission Conside...

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Information Control, Electrical Engineering and Rail Transit (ICEERT), International Conference on

作者： Xuan Fan Lili Wen Caoyang Cheng Qian Zhou Li Fan Yuan Zhu Honhjie Yu Piao Du Xinxin Fang State Grid Chongqing Economic Research Institute Chongqing China State Key Laboratory of Power Transmission Equipment & System Security and New Technology College of Electrical Engineering Chongqing University Chongqing China State Grid Chongqing Electric Power Company Chongqing China

Power resources and demand in China are in opposite directions, leading to the requirements of tie-line power exchanges. A good characterization of the feasible region of tie-line transmission plays a vital role in improving the utilization efficiency of tie-line power exchanges. With the increase of converter stations in power systems, the feasible region of tie-line transmission considering converter stations is for the first time studied in this paper. A bi-level determination method is presented for the characterization. In the upper level, impacts of integer variables in converter stations are incorporated into the feasible region by exploring the critical combinations of integer variables that are associated with boundaries of the feasible region. In the lower level, the operational constraints with the found integer variables are projected to the domain of tie-line transmission by the existing algorithms. The effectiveness of the presented methods is demonstrated in a modified IEEE 5-bus test system.

关键词： Rails Electrical engineering Transformers

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Generalized Zeroing Neural Network Model for Online Solving Time-Varying Cube Roots with Various External Disturbances in Different Domain

SSRN

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SSRN 2022年

作者： Wang, Gang Liu, Yongbai Sun, Yingyi Yu, Junzhi Sun, Zhongbo Department of Mechatronic Engineering Changchun University of Technology Changchun130012 China College of Economics and Management Jilin Agricultural University Changchun130118 China State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering Science BIC-ESAT College of Engineering Peking University Beijing100871 China Department of Control Engineering Changchun University of Technology Changchun130012 China

As a basic problem of the nonlinear dynamic model, the online solution of time-varying cube root problem (TVCRP) is widely used in science and engineering. However, the practical system is frequently disturbed by the external factors, which inevitably leads to unknown disturbances in the solution process. Therefore, addressing the TVCRP with high accuracy in non-ideal environment (unknown disturbances) is the basis of solving the nonlinear dynamic model. In this work, a noise-suppression zeroing neural dynamics (NSZND) model is investigated and developed from the control perspective to resolve the time-varying or time-invariant cube root problem (TV/TICRP) under the different disturbances (bounded and unbounded disturbances) in © 2022, The Authors. All rights reserved.

关键词： Dynamic models

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Surface Nanostructures and Formation Mechanism on TeO_(2)Induced by Swift Heavy Ions under Grazing Incidence

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IMP & HIRFL Annual Report 2022年第1期 113-114页

作者： Zhai Pengfei Xu Lijun Hu Yuhui Nan Shuai Wang Wentao Li Weixing Liu Jie Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China School of Materials&Energy Lanzhou UniversityLanzhou 730000China State Key Laboratory of Tibetan Plateau Earth System Science Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Songshan Lake Materials Laboratory Dongguan 523808GuangdongChina

Surface nanostructures(surface ion track)such as multiple nanodots or/and groove could be produced by single heavy ions(SHIs),when some materials are irradiated with SHIs under grazing *** creation of equally spaced nanodots on the surface of the irradiated SrTiO_(3)single crystal with grazing SHIs was previously explained as the periodic oscillation of electronic energy loss^([1]).

关键词： irradiated oscillation explained

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Adaptive Robust Control of an Uncertain robotic Manipulator with Guaranteed Transient and Steady state Performance

Adaptive Robust Control of an Uncertain Robotic Manipulator ...

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International Conference on Advanced robotics and Mechatronics (ICARM)

作者： Yifan Liu Dejie Yu Zilu Wang Zheshuo Zhang Hui Yin State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha P. R. China Intelligent Transportation System Research Center School of information and electrical engineering Zhejiang Uni-versity City College Hangzhou Zhejiang P. R. China School of Mechanical and Automotive Engineering South China University of Technology Guangzhou Guangdong P. R. China

Guaranteeing human-specified performance in robot control subject to complex uncertainties is challenging. This study takes time-varying (possibly fast), bounded with unknown bounds uncertainties into consideration in controlling an uncertain robotic manipulator system (URMS). We employ an adaptive law to on-line estimate the unknown bounds for uncertainty compensation, and prescribed transient and steady state performance (TSSP) are guaranteed by using a state transformation technique. As a result, a class of adaptive robust control with prescribed TSSP is proposed. Simulation results are provided to validate the effectiveness of the proposed approach.

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Hierarchical Nb2o5@Zno Hetero-Branched Nanorods for Enhanced H2s Gas Sensing

SSRN

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SSRN 2022年

作者： Wu, Tao Tao Zhu, Liyuan Wu, Xue-Yan Miao, Xiao-Yong Mao, Li-Wen Jin, Xuan-Hong Lu, Hong-Liang State Key Laboratory of ASIC and System Shanghai Institute of Intelligent Electronics & Systems School of Microelectronics Fudan University Shanghai 200433 China School of Optical-Electrical & Computer Engineering University of Shanghai for Science and Technology Shanghai 200093 China Yiwu Research Institute of Fudan University Chengbei Road Zhejiang Yiwu City322000 China

Hierarchical Nb 2 O 5 @ZnO hetero-branched nanorods used for highly responsive, selective, and stable hydrogen sulfide (H 2 S) sensors were synthesized through a sequential process combining a hydrothermal method, atomic-layer-deposition processing, and modified hydrothermal processing for branching ZnO nanowires. The Nb 2 O 5 @ZnO hetero-branched nanorod sensors exhibited a great response (R a /R g ) of 6.10 towards 20 ppm H 2 S at an optimal working temperature of 400 o C, whose resistance changing rate (~5.10) was 39.2- and 1.9-fold those of Nb 2 O 5 (~0.13) and Nb 2 O 5 @ZnO core-shell nanorod (~2.74) sensors, respectively. The heterojunction formed at the Nb 2 O 5 @ZnO interface and the characteristic reaction between ZnO and H 2 S effectively improved H 2 S sensing performance. Moreover, the branching of ZnO nanowires introduced abundant homojunctions and prominently enlarged the specific surface area, further increasing the response of hetero-branched sensors. Meanwhile, the Nb 2 O 5 @ZnO hetero-branched sensors maintained steady performance over a month, indicating good stability and repeatability. In a word, such hierarchical Nb 2 O 5 @ZnO hetero-branched nanorod gas sensors are promising for the development of sensitive and selective H 2 S detection. © 2022, The Authors. All rights reserved.

关键词： Zinc oxide

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Granular dynamics in auger sampling

arXiv

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arXiv 2022年

作者： Feng, Yajie Huang, Shuo Pang, Yong Huang, Kai Liu, Caishan State Key Laboratory of Turbulence and Complex System College of Engineering Peking University Beijing100871 China Beijing Spacecrafts China Academy of Space Technology Beijing100090 China Division of Natural and Applied Sciences Duke Kunshan University Jiangsu Kunshan215306 China Experimentalphysik V Universiẗat Bayreuth Bayreuth95440 Germany

From geotechnical applications to space exploration, auger drilling is often used as a standard tool for soil sample collection, instrument installation, and others. Focusing on granular flow associated with the rotary drilling process, we investigate the performance of auger drilling in terms of sampling efficiency, defined as the mass ratio of the soil sample collected in the coring tube to its total volume at a given penetration depth, by means of experiments, numerical simulations, as well as theoretical analysis. The ratio of rotation to penetration speed is found to play a crucial role in the sampling process. A continuum model for the coupled granular flow in both coring and discharging channels is proposed to elucidate the physical mechanism behind the sampling process. Supported by a comparison to experimental results, the continuum model provides a practical way to predict the performance of auger drilling. Further analysis reveals that the drilling process approaches a steady state with constant granular flow speeds in both channels. In the steady state, sampling efficiency decreases linearly with the growth of the rotation to penetration speed ratio, which can be well captured by the analytical solution of the model. The analytical solution also suggests that the sampling efficiency is independent of gravity in the steady state, which has profound implications for extraterrestrial sample collection in future space missions. Copyright © 2022, The Authors. All rights reserved.

关键词： Granular materials

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A Framework of Cloud-Edge Collaborated Digital Twin for Flexible Job Shop Scheduling with Conflict-Free Routing

SSRN

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SSRN 2023年

作者： Gao, Qianfa Fu, G.U. Li, Linli Guo, Jianfeng State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou310027 China Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province School of Mechanical Engineering Zhejiang University Hangzhou310027 China Department of Industrial and System Engineering Zhejiang University Hangzhou310027 China National Institute of Innovation Management Zhejiang University Hangzhou310015 China Center of Engineering Management Polytechnic Institute Zhejiang University Hangzhou310015 China School of Public Policy and Management University of Chinese Academy of Sciences Beijing100049 China Institutes of Science and Development Chinese Academy of Sciences Beijing100190 China

Synchronous scheduling of automated guided vehicles (AGVs) and production resources can effectively improve the productivity of automated flexible job shop, but limited transportation resources and persistent abnormal disturbance compromise the accuracy and reliability of such scheduling. To address the flexible job shop scheduling problem with limited transportation resources (FJSP-T) under abnormal disturbance, in this article we establish a time-space network based zero-one programming (TSN-ZOP) model to optimize makespan, and propose a cloud-edge combined digital twin flexible job shop scheduling (CE-DTFJSS) framework to realize real-time scheduling. In this framework, a digital twin (DT) system is employed, and a cloud-edge architecture is introduced to allocate computing resources for scheduling-supporting tasks including DT simulation, state monitoring, and transportation perception. Specifically, we develop a cloud edge collaboration rescheduling strategy based on rolling window, to update the parameters of scheduling from real-time data and to execute real-time scheduling optimization. To realize scheduling and conflict-free routing planning simultaneously, a multi-layer coding evolutionary algorithm nested time window Dijkstra is adopted as a solution approach. The effectiveness and efficiency of CE-DTFJSS are verified by a numeric simulation based on a real case of automobile welding workshop. The simulation results show that compared with the scheduling scheme without considering AGVs routing problem, CE-DTFJSS can reduce makespan by 7.11%, and real-time scheduling can be achieved in 0.1 seconds. © 2023, The Authors. All rights reserved.

关键词： Automatic guided vehicles

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