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On the variation of water resource structure in the Lower Yellow River

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Science china(Technological Sciences) 2004年第Z1期47卷 127-141页

作者： NI Jinren1. WANG Yudong1. QIAN Zhenghan1. {3. Tianhong1.& {1. Yean2.1. Department of Environmental Engineering, Peking University The Key Laboratory of Water and Sedi- ment Sciences, Ministry of Education, beijing 1.0871. china 2. {13. of Hydrau{3.c Research, Yellow River Conservancy Commission, Zhengzhou 450003. china Department of Environmental Engineering Peking University Beijing China The Key Laboratory of Water and Sediment Sciences Ministry of Education Beijing China institute of Hydrau{1.c Research YellowRiver Conservancy Commission Zhengzhou China

In view of river functions and the Minimum Water Demand for River Ecosystem (MWDRE), the water resources in the Lower Yellow River is further divided into three portions, i.e. water available for ecosystem (WE), water exploitable for socioeconomic purposes (WS) and excess flood water (WF). Corresponding conceptions and practical significances are expounded in details. The annual amount of the three portions of water resources from 1.50 to 2.01.is worked out on the basis of the daily hydrologic data, and the division of different portions is discussed. The results indicate that although the essential water demand for river functions is considered preferentially, the amount of the WE has decreased dramatically while its proportion increased gradually since the 1.50s, and the shortage to the MWDRE increased markedly; both the amount and the proportion of the WS decreased notably. Since the 1.90s, the actual water consumption for socioeconomic purposes in the lower reaches of the river basin has already exceeded the maximum amount of the WS and has to take over the WE which is already insufficient, hence not only the normal river functions are further disturbed and the river course shrinks greatly, but also the proportion and potential danger of the WF show no decreasing tendency in spite of the sharp decrease of upstream runoff.

关键词： the Yellow River, water resource structure, water available for ecosystem, water exploitable for socioeconomic purposes, excess flood water.

Origin of the Red Earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

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Science china Earth Sciences 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2. JI Junfeg3. WANG Xiaoyong1,7, zhao Jingbo4, HUANG Baochun5 & li Zhen6 1. SKLLQG, {2. of Earth Environment, chinese academy of Sciences, Xi’an 710075, china 2. Department of Urban and Resources Sciences, Nanjing University, Nanjing 2.0093. china 3. Department of Earth Sciences, Nanjing University, Nanjing 2.0093. china 4. Department of Geography, Shaanxi Normal University, Xi’an 710062. china 5. {2. of Geology and Geophysics, chinese academy of Sciences, {12. 10002., china 6 Department of Geography, Qinghai Normal University, Xining 810008, china 7. Graduate School of the chinese academy of Sciences, {12. 10003., china SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate School of the chinese {1. of Sciences Beijing China Department of Urban and Resources Sciences Nanjing University Nanjing China Department of Earth Sciences Nanjing University Nanjing China Department of Geography Shaanxi Normal University Xi’an China institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Department of Geography Qinghai Normal University Xining China

The Red Earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red Earth sequenceconsists of 2. visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the {1.Loess Plateau. Grain-size analysis shows that the Red Earth deposit is very fine-grained with anegligible sand fraction ( > 63.μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 1. μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63.μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red Earth *** REE distributions of the loess-soil and the Red Earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red Earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the RedEarth deposition predates 1..4 Ma BP (1..6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red Earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red Earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.

Using lightning locating system based on time-of-arrival technique to study three-dimensional lightning discharge processes

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Science china Earth Sciences 2010年第4期53卷 591-602页

作者： ZHANG GuangShu1,WANG YanHui1,QIE XiuShu2.ZHANG Tong1,zhao YuXiang1,3.li YaJun1 & CAO DongJie11 Laboratory for Climate Environment and Disasters of Western china,Cold and Arid Regions Environmental and Engineering Research institute,chinese academy of Sciences,Lanzhou 73.000,china 2.Laboratory for Middle Atmosphere and Global Environment Observation(LAGEO),institute of Atmospheric Physics,chinese academy of Sciences,{13. 10002.,china 3.Department of Physics,Tianshui Normal College,Tianshui 741001,china Laboratory for Climate Environment and Disasters of Western {1. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China Laboratory for Middle Atmosphere and Global Environment Observation (LAGEO) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of Physics Tianshui Normal College Tianshui China

A time-of-arrival(TOA) system based on GPS technology for locating VHF radiation sources from lightning has been developed and used in observation sites in the northern Shandong Province,*** 3. images of the lightning progression have been obtained successfully for the first time in *** 3.-channel evolutions of typical negative CG,positive CG and IC lightning flashes have been discussed together with the data of fast electric field *** was found that significant differences existed between the negative and positive CG lightning flashes in terms of the initiation and propagation of the radiation *** preliminary breakdown of a negative CG lightning flash propagated at a speed about 5.2.1.4 m/*** stepped leader of negative CG lightning flashes was trigged by negative initial ***,it propagated downward at a speed of 1.3.1.5 m/*** initial process of the positive CG lightning flashes was also a propagation process of negative *** streamers propagated dominantly horizontally in the positive charge region and accumulated positive charges at the origin of the lightning,and as a consequence,initiated downward positive streamers.A new type of lightning discharge that was triggered by a narrow bipolar pulse(NBP) is discussed in this *** NBP was originated at altitude of about 1..5 km in the upper positive charge *** a distinct difference from normal IC flash,its channels extended horizontally all around and produced a lot of radiation *** source power of the NBP could approach 1..7 kW,which is much greater than that of normal lightning discharge ranging between 1.0 mW and 500 *** 3. propagation of this new type of lightning discharge was observed and obtained for the first time in *** possible initiation mechanism of this new type of light-ning is discussed here.

关键词： time-of-arrival(TOA) technique three dimensional lightning locating system discharge process narrow bipolar pulse new-type of IC lightning

Applications of functionalized ionic liquids

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Science china Chemistry 2006年第5期49卷 385-401页

作者： li Xuehui1. {1. Dongbin{3.3. FEI {1.fu2.& WANG Lefu1.1. Department of Chemical Engineering, Guangdong Provincial Laboratory of Green Chemical Technology, South china Uni-versity of Technology, Guangzhou 51.641. china {3. Swiss Federal {13. of Technology, Lausanne, EPFL, CH-1.1. Lausanne, Switzerland 3. PKU Green Chemistry Center, beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, beijing 1.0871. china Department of Chemical Engineering Guangdong Provincial Laboratory of Green Chemical Technology South China University of Technology Guangzhou China Lausanne EPFL Swiss Federal Institute of Technology Lausanne Switzerland PKU Green Chemistry Center Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University Beijing China

Recent developments of the synthesis and applications of functionalized ionic liquids (including dual-functionalized ionic liquids) have been highlighted in this review. Ionic liquids are at-tracting attention as alternative solvents in green chemistry, but as more functionalized ILs are pre-pared, a greater number of applications in increasingly diverse fields are found.

关键词： ionic liquids functionalized ionic liquids dual-functionallzed ionicliquids reaction media asymmetric synthesis nano-materials porous materials lubricants flue-gas desulfurization oil desul-furization

Probabilistic seismic inversion based on physics-guided deep mixture density network

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Petroleum Science 2024年第3期21卷 1611-1631页

作者： Qian-Hao Sun zhao-Yun Zong Xin {1. National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina Laoshan Laboratory Qingdao266580ShandongChina CNOOC Research institute Ltd. Beijing100028China

Deterministic inversion based on deep learning has been widely utilized in model parameters *** by logging data,seismic data,wavelet and modeling operator,deterministic inversion based on deep learning can establish nonlinear relationships between seismic data and model ***,seismic data lacks low-frequency and contains noise,which increases the non-uniqueness of the *** conventional inversion method based on deep learning can only establish the deterministic relationship between seismic data and parameters,and cannot quantify the uncertainty of *** order to quickly quantify the uncertainty,a physics-guided deep mixture density network(PG-DMDN)is established by combining the mixture density network(MDN)with the deep neural network(DNN).Compared with Bayesian neural network(BNN)and network dropout,PG-DMDN has lower computing cost and shorter training time.A low-frequency model is introduced in the training process of the network to help the network learn the nonlinear relationship between narrowband seismic data and low-frequency *** addition,the block constraints are added to the PG-DMDN framework to improve the horizontal continuity of the inversion *** illustrate the benefits of proposed method,the PG-DMDN is compared with existing semi-supervised inversion *** synthetic data examples of Marmousi II model are utilized to quantify the influence of forward modeling part,low-frequency model,noise and the pseudo-wells number on inversion results,and prove the feasibility and stability of the proposed *** addition,the robustness and generality of the proposed method are verified by the field seismic data.

关键词： Deep learning Probabilistic inversion Physics-guided Deep mixture density network

Distributed adaptive prescribed-time orbit containment control for satellite cluster flight

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chinese Journal of Aeronautics 2024年第8期37卷 342-357页

作者： Tingting ZHANG Shijie ZHANG Huayi li Xiangtian {1. Research Center of Satellite Technology Harbin Institute of TechnologyHarbin 150080China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

The distributed prescribed-time orbit containment control for the satellite cluster flight with multiple dynamic leaders is *** directed information communication topology between followers is taken into account in the overall *** the satellite mass is assumed to be constant,a distributed prescribed-time orbit containment controller is,firstly,presented to drive the followers into the dynamic convex hull produced by multiple ***,the parameter uncertainty is considered,and a prescribed-time sliding mode estimator is introduced to estimate the desired velocity of each *** on the estimated state,a novel distributed adaptive prescribed-time orbit containment control scheme is *** Lyapunov stability theory is utilized to prove the prescribed-time stability of the closed-loop ***,several numerical simulations and comparison of different control methods are provided to verify the effectiveness and superiority of the proposed control method.

关键词： Satellite cluster Orbit containment control Prescribed-time control Parameter uncertainty Directed communication graph

Polyp-Canal Reconstruction Reveals Evolution Toward Complexity in Corals

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Research 2024年第1期2023卷 417-428页

作者： Yixin li Xin liao Xin Wang Yuanchao li Hongwei {3. Yunpeng {3. Junyuan Chen Chunpeng He Zuhong Lu State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Guangxi Key Lab of Mangrove Conservation and Utilization Guangxi Mangrove Research CenterGuangxi Academy of SciencesBeihai 536000China Hainan academy of Ocean and Fishery Sciences Haikou 571126China State Key Laboratory of Marine Resources Utilization in South {1. Sea Hainan UniversityHaikou 570228China Nanjing institute of Geology and Palaeontology Chinese Academy of Sciences39 East Beijing RoadNanjing 210008China

Modern scleractinian corals are classified into robust,complex,and basal clades through comparative molecular ***,only few morphological or biological criteria can systematically determine the evolutionary trajectories of these major scleractinian coral ***,we obtained the structural information of 2.0}scleractinian coral species representing robust and complex clades:High-resolution micro-computed tomography was used to reconstruct the polyp-canal systems in their colonies and to visualize the dynamic polyp growth *** found that the emergence of mesh-like canals may distinguish representatives of complex and robust *** differences in polyp-canal connections suggest distinct evolutionary trajectories among coral species:The formation of the canal network promoted the development of more complex coral structures,and coral polyps within this network formed calices of very similar volume,following precise axial growth *** influence of individual polyps on the coral colony becomes less significant as coral structures become more complex,and coral species with more complicated polyp-canal systems occupied niches more *** work supplements current evolutionary studies on reef-building corals,providing insight for further studies on coral growth patterns.

关键词： Coral representing directions

Corrosion Behavior of Graphene Nanosheets Reinforced Magnesium Matrix Composites in Simulated Body Fluids

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 525-536页

作者： liwen Chen Jianhui Jing Lulu Zhang Jing li Weipeng Chen limin li Yuan zhao Hua Hou Yuhong zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan 030051China Shanxi Key Laboratory of Advanced Manufacturing Technology School of Mechanical EngineeringNorth University of ChinaTaiyuan 030051China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China institute of Materials Intel{1.gent Technology Liaoning Academy of MaterialsShenyang 110004China

Magnesium(Mg)alloy is considered as a promising biodegradable implant material but restricted to rapid ***,the new strategies based on thixomolding process had been explored to utilize the outstanding anti-permeability of graphene nanosheets(GNPs)while inhibit its galvanic corrosion with the matrix,so as to improve the corrosion resistance of *** agglomerate of GNPs with 0.9 wt%content is the main reason for the deterioration of corrosion performance due to the formation of micro-galvanic *** grain refinement of composites with 0.6 wt%content had positive effects on the better corrosion *** process adjusting,the unique distributions of GNPs along grain boundaries play a vital role in improving the corrosion *** can be ascribed to the following mechanisms:(I)The barriers can be established between the Mg matrix and corrosive medium,hence blocking the charge transfer at the interface;(II)The GNPs can effectively promote apatite deposition on the Mg matrix,leading to form dense apatite layers and prevent the further invasion of SBF;(III)The GNPs acting as reinforcements exists in the corrosion layer and apatite layer,impede the apatite layer falling off from the Mg *** findings broaden the horizon for biomedical applications in Mg matrix composites to realize desired performances.

关键词： Magnesium matrix composite Graphene nanosheets Corrosion resistance

Learning Scalable Task Assignment with Imperative-Priori Conflict Resolution in Multi-UAV Adversarial Swarm Defense Problem

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Journal of Systems Science & Complexity 2024年第1期37卷 369-388页

作者： zhao Zhixin CHEN Jie XIN Bin {1. {1. JIAO Keming ZHENG Yifan School of Electronics and Information Engineering Tongji UniversityShanghai 201804China Shanghai institute of Intel{1.gent Science and Technology Tongji UniversityShanghai 201804China School of Automation Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Autonomous Intelligent Unmanned Systems Beijing 100081China Shanghai institute of Intel{1.gent Science and Technology Tongji UniversityShanghai 201804China.

The multi-UAV adversary swarm defense(MUASD)problem is to defend a static base against an adversary UAV swarm by a defensive UAV *** the problem into task assignment and low-level interception strategies is a widely used ***-based approaches for task assignment are a promising *** studies on learning-based methods generally assume decentralized decision-making architecture,which is not beneficial for conflict *** contrast,centralized decision-making architecture is beneficial for conflict resolution while it is often detrimental to *** achieve scalability and conflict resolution simultaneously,inspired by a self-attention-based task assignment method for sensor target coverage problem,a scalable centralized assignment method based on self-attention mechanism together with a defender-attacker pairwise observation preprocessing(DAP-SelfAtt)is ***,an imperative-priori conflict resolution(IPCR)mechanism is proposed to achieve conflict-free ***,the IPCR mechanism is parallelized to enable efficient *** validate the algorithm,a variant of proximal policy optimization algorithm(PPO)is employed for training in scenarios of various *** experimental results show that the proposed algorithm not only achieves conflict-free task assignment but also maintains scalability,and significantly improve the success rate of defense.

关键词： Conflict resolution reinforcement learning scalability task assignment.