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Patterns and trajectories of macrophyte change in East China’s shallow lakes over the past one century

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Science China Earth Sciences 2021年第10期64卷 1735-1745页

作者： Feifan HUANG ke ZHANG Shixin HUANG qi LIN State key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China

Macrophytes play important roles in maintaining ecosystem health and stability of shallow *** understanding of their long-term dynamics has important theoretical and practical significance for both lake ecosystem restoration and eutrophication ***,the knowledge about the historical status and changing patterns of macrophytes in China’s shallow lakes is still controversial and lacks systematic ***,we reviewed and synthesized the published records of submerged macrophytes from 14 typical shallow lakes in the eastern plain covering the past 100 *** results suggest that submerged macrophytes have experienced three clear stages of change:rare period(the 1900s–the 1950s),growth period(the 1950s–the 1980s),and recession period(the 1980s–now).This finding is different from the traditional understanding that submerged macrophytes were abundant in the early 20th century and have been degrading since *** this basis,we proposed the possible evolution pattern(less-more-less)of submerged macrophytes in the eastern plain lake region over the past 100 years,which provides new perspectives about the long-term evolution process of macrophytes in shallow ***,we found that the decline of submerged macrophytes during the regime shift shows a gradual process at the interdecadal scale;this finding contradicts the classical regime shift theory that macrophytes decline sharply during the critical *** study has important theoretical value for the restoration of the eastern plain lakes in China from“turbid lake”to“clear lake”,especially for establishing the historical reference condition and restoration path of macrophytes.

关键词： Macrophyte Submerged macrophyte Eutrophication Shallow lakes Regime shift Climate change

Direct Dynamics Study on CH_2O + CH_3~·→ CHO + CH_4 Reaction

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Chinese Chemical Letters 2006年第4期17卷 565-568页

作者： Yan qi ke Li HAN State key Laboratory of Molecular Reaction Dynamic Dalian Institute of Chemical Physics Chinese Academy of Science Dalian 116023

It is still a formidable challenge to study CH2O ＋ CH3·→ CHO ＋ CH4 reaction in the gas phase by traditional dynamics, because of the large number of freedom degrees for the system. In this paper, direct dynamics, in which trajectories were run directly on the DFT potential energy surface, have been applied to the reaction, which gave a direct look in the reaction processes. Two sets of trajectories at different initial orientations of reactants and temperature have been simulated. And the detailed reaction mechanisms have been described.

关键词： Direct dynamics DFT reaction mechanism.

Ablation characteristics of carbon-doped glycerol irradiated by a 1064 nm nanosecond pulse laser

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Plasma Science and Technology 2018年第3期20卷 151-155页

作者： Jing qi Siqi ZHANG Tian LIANG ke XIAO Weichong TANG,Zhiyuan zheng School of Science China University of Geosciences Beijing 100083 People＇s Republic of China

The ablation characteristics of carbon-doped glycerol were investigated in laser plasma propulsion using a pulse laser with 10 ns pulse width and 1064 nm wavelength. The results showed that with the incident laser intensity increasing, the target momentum decreased. Results still indicated that the strong plasma shielded the consumption loss and resulted in a low coupling coefficient. Furthermore, the carbon-doping gave rise to variations in the laser focal position and laser intensity, which in turn reduced the glycerol splashing. Based on the glycerol viscosity and the carbon doping, a high specific impulse is anticipated.

关键词： laser ablation plasma propulsion carbon-doped glycerol

A Cloud Framework for High Spatial Resolution Soil Moisture Mapping from Radar and Optical Satellite Imageries

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Chinese Geographical Science 2023年第4期33卷 649-663页

作者： GUO Tianhao zheng Jia WANG Chunmei TAO Zui zheng Xingming WANG qi LI Lei FENG Zhuangzhuang WANG Xigang LI Xinbiao ke Liwei Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China State key Laboratory of Black Soils Conservation and Utilization Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China Changchun Jingyuetan Remote Sensing Test Site Changchun 130102China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China China Centre for Resources Satellite Data and Application China Aerospace Science and Technology CorporationBeijing 100094China College of Geoexploration Science and Technology Jilin UniversityChangchun 130026China School of Geomatics and Prospecting Engineering Jilin Jianzhu UniversityChangchun 130118China

Soil moisture plays an important role in crop yield estimation,irrigation management,*** sensing technology has potential for large-scale and high spatial soil moisture ***,offline remote sensing data processing is time-consuming and resource-intensive,and significantly hampers the efficiency and timeliness of soil moisture *** to the high-speed computing capabilities of remote sensing cloud platforms,a High Spatial Resolution Soil Moisture Estimation Framework(HSRSMEF)based on the Google Earth Engine(GEE)platform was developed in this *** functions of the HSRSMEF include research area and input datasets customization,radar speckle noise filtering,optical-radar image spatio-temporal matching,soil moisture retrieving,soil moisture visualization and *** paper tested the performance of HSRSMEF by combining Sentinel-1,Sentinel-2 images and insitu soil moisture data in the central farmland area of Jilin Province,*** Normalized Difference Vegetation Index(NDVI)based on the Savitzky-Golay algorithm conforms to the crop growth cycle,and its correlation with the original NDVI is about 0.99(P<0.001).The soil moisture accuracy of the random forest model(R 2=0.942,RMSE=0.013 m3/m3)is better than that of the water cloud model(R 2=0.334,RMSE=0.091 m3/m3).HSRSMEF transfers time-consuming offline operations to cloud computing platforms,achieving rapid and simplified high spatial resolution soil moisture mapping.

关键词： soil moisture(SM) Google Earth Engine(GEE) Cloud Computing Platform High Spatial Resolution Soil Moisture Estimation Framework(HSRSMEF) remote sensing Sentienl-1 Sentinel-2 Northeast China

Low Dimensional Chaos from the Group Sunspot Numbers

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Chinese Journal of Astronomy and Astrophysics 2007年第3期7卷 435-440页

作者： qi-Xiu Li ke-Jun Li National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 Graduate School of Chinese Academy of Sciences Beijing 100049

We examine the nonlinear dynamical properties of the monthly smoothed group sunspot number Rg and find that the solar activity underlying the time series of Rg is globally governed by a low-dimensional chaotic attractor. This finding is consistent with the nonlinear study results of the monthly Wolf sunspot numbers. We estimate the maximal Lyaponuv exponent （MLE） for the Rg series to be positive and to equal approximately 0.0187 ± 0.0023 （month^- 1）. Thus, the Lyaponuv time or predictability time of the chaotic motion is obtained to be about 4.46 ± 0.5 years, which is slightly different with the predictability time obtained from Rz. However, they both indicate that solar activity forecast should be done only for a short to medium term due to the intrinsic complexity of the time behavior concerned.

关键词： Sun activity - Sun sunspot - chaos - Sun Wolf sunspot numbers

Estimation of distribution algorithm enhanced particle swarm optimization for water distribution network optimization

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Frontiers of Environmental Science & Engineering 2016年第2期10卷 341-351页

作者： Xuewei qi ke LI Walter D. POTTER Department of Electrical and Computer Engineering University of California Riverside CA 92507 USA College of Engineering University of Georgia Athens GA 30605 USA Institute of Artificial Intelligence University of Georgia Athens GA 30605 USA

The optimization of a water distribution network （WDN） is a highly nonlinear, multi-modal, and constrained combinatorial problem. Particle swarm opti- mization （PSO） has been shown to be a fast converging algorithm for WDN optimization. An improved estimation of distribution algorithm （EDA） using historic best positions to construct a sample space is hybridized with PSO both in sequential and in parallel to improve population diversity control and avoid premature conver- gence. Two water distribution network benchmark exam- ples from the literature are adopted to evaluate the performance of the proposed hybrid algorithms. The experimental results indicate that the proposed algorithms achieved the literature record minimum （6.081 MS） for the small size Hanoi network. For the large size Balerma network, the parallel hybrid achieved a slightly lower minimum （1.921M） than the current literature reported best minimum （1.923MC）. The average number of evaluations needed to achieve the minimum is one order smaller than most existing algorithms. With a fixed, small number of evaluations, the sequential hybrid outperforms the parallel hybrid showing its capability for fast convergence. The fitness and diversity of the populations were tracked for the proposed algorithms. The track record suggests that constructing an EDA sample space with historic best positions can improve diversity control significantly. Parallel hybridization also helps to improve diversity control yet its effect is relatively less significant.

关键词： particle swarm optimization (PSO) diversitycontrol estimation of distribution algorithm (EDA) waterdistribution network (WDN) premature convergence,hybrid strategy

Real-time urban traffic information estimation with a limited number of surveillance cameras

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Frontiers of Computer Science 2012年第5期6卷 547-559页

作者： Guangtao XUE ke ZHANG qi HE Hongzi ZHU Department of Computer Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Baidu Corporation Shanghai 201203China

Constant traffic congestion consumes enormous amounts of energy and causes vastly increased journey times. Therefore, real-time traffic information is of great importance to the public because such information is invaluable to more efficient traffic control and travel planning. To obtain such information in metropolises like Shanghai, however, is very challenging due to the extraordinarily large scale and com- plexity of the underlying road network. In this paper, we pro- pose a novel traffic estimation scheme utilizing surveillance cameras pervasively deployed in cities. With only a limited number of roads with cameras, we adopt a measurement- based traffic matrix （TM） estimation method to infer the traf- fic conditions on those roads with no cameras. Extensively trace-driven simulations as well as field study results show that our scheme can achieve high accuracy with a very limited number of measurements. The accuracy of our measurement- based algorithm outperforms the traditional speed-based and model-based approaches by up to 50%.

关键词： real-time traffic information surveillance cameras measurement-based traffic matrix estimation topologypruning

Blackboard Mechanism Based Ant Colony Theory for Dynamic Deployment of Mobile Sensor Networks

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Journal of Bionic Engineering 2008年第3期5卷 197-203页

作者： Guang-ping qi Ping Song ke-jie Li School of Aerospace Science and Engineering Beij＇ing Institute of Technology Beo＇ing 100081 P. R. China

A novel bionic swarm intelligence algorithm, called ant colony algorithm based on a blackboard mechanism, is proposed to solve the autonomy and dynamic deployment of mobiles sensor networks effectively. A blackboard mechanism is introduced into the system for making pheromone and completing the algorithm. Every node, which can be looked as an ant, makes one information zone in its memory for communicating with other nodes and leaves pheromone, which is created by ant itself in naalre. Then ant colony theory is used to find the optimization scheme for path planning and deployment of mobile Wireless Sensor Network （WSN）. We test the algorithm in a dynamic and unconfigurable environment. The results indicate that the algorithm can reduce the power consumption by 13% averagely, enhance the efficiency of path planning and deployment of mobile WSN by 15% averagely.

关键词： ant colony algorithm wireless sensor network blackboard mechanism bionic swarm intelligence algorithm

Facile fabrication of Fe/Zr binary MOFs for arsenic removal in water:High capacity,fast kinetics and good reusability

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Journal of Environmental Sciences 2023年第6期128卷 213-223页

作者： qi Guo Yuan Li Li-Wei zheng Xiao-YangWei Yan Xu Yi-Wen Shen ke-Gang Zhang Chun-Gang Yuan Hebei key Lab of Power Plant Flue Gas Multi-Pollutants Control Department of Environmental Science&EngineeringNorth China Electric Power UniversityBaoding 071000China Wetland Research Center for Baiyangdian Lake North China Electric Power UniversityBaoding 071000China

A water-stable bimetallic Fe/Zrmetal-organic framework[UiO-66(Fe/Zr)]for exceptional decontamination of arsenic in water was fabricated through a facile one-step *** batch adsorption experiments revealed the excellent performances with ultrafast adsorption kinetics due to the synergistic effects of two functional centers and large surface area(498.33 m^(2)/g).The absorption capacity of UiO-66(Fe/Zr)for arsenate[As(V)]and arsenite[As(III)]reached as high as 204.1 mg/g and 101.7 mg/g,*** model was suitable to describe the adsorption behaviors of arsenic on UiO-66(Fe/Zr).The fast kinetics(adsorption equilibrium in 30min,10mg/L As)and pseudo-second-ordermodel implied the strong chemisorption between arsenic ions and UiO-66(Fe/Zr),which was further confirmed by DFT theoretical *** results of FT-IR,XPS analysis and TCLP test demonstrated that arsenic was immobilized on the surface of UiO-66(Fe/Zr)through Fe/Zr-O-As bonds,and the leaching rates of the adsorbed As(III)and As(V)from the spent adsorbent were only 5.6%and 1.4%,***-66(Fe/Zr)can be regenerated for five cycles without obvious removal efficiency *** original arsenic(1.0mg/L)in lake and tapwater was effectively removed in 2.0 hr[99.0%of As(III)and 99.8%of As(V)].The bimetallic UiO-66(Fe/Zr)has great potentials in water deep purification of arsenic with fast kinetics and high capacity.

关键词： Arsenic Removal Metal-organic frameworks Bimetallic