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Kinetics and products of ozonation of *** Red 195 in a semi-batch reactor

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Chinese Chemical Letters 2015年第1期26卷 93-99页

作者： Rui Zhang Dong-xing yuan Bao-Min Liu College of the Environment & Ecology Xiamen University State Key Laboratory of Marine Environmental Science Xiamen University

Textile wastewater shows great threats to the environment if not well pretreated before discharge. A promising technique, ozonation, was applied to remove the color in dye solutions containing C.I. Reactive Red 195 （RR195） in a semi-batch reactor. The decolorization of RRI95 by the ozone process followed pseudo-first-order kinetics. Several factors which influenced the efficiency of decolorization were studied and the reaction rate constant （k） obtained with different operational parameters was compared. Our results showed that RRI95 was more easily degraded in acidic than in alkaline conditions. The dyeing auxiliaries （sodium carbonate and sodium chloride） that acted as radical scavengers could enhance the decolorization process, and the ozonation time for total color removal lengthened if the initial dye concentration was higher. The analysis of the ozonation products was performed by liquid chromatography-tandem mass spectrometer and a possible degradation pathway was predicted according to the ozonation products and structure of RR195. Our results indicated that ozonation was effective in the color removal of dyes, but further treatment might be necessary since the ozonation products are high toxic.

关键词： Ozonation C.I. Reactive Red 195 Decolourization Kinetics Degradation pathway

Adaptive Tracking Control of Mobile Manipulators with Affine Constraints and Under-actuated Joints

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International Journal of Automation and computing 2018年第6期15卷 728-735页

作者： Wei Sun Wen-xing yuan Yu-Qiang Wu School of Mathematics Science Liaocheng University Liaocheng 252000 China Institute of Automation Qufu Normal University Qufu 273165 China

Adaptive motion/force tracking control is considered for a class of mobile manipulators with affine constraints and under-actuated joints in the presence of uncertainties in this paper. Dynamic equation of mobile manipulator is transformed into a controllable form based on dynamic coupling technique. In view of the asymptotic tracking idea and adaptive theory, adaptive controllers are proposed to achieve the desired control objective. Detailed simulation results confirm the validity of the control strategy.

关键词： Tracking control affine constraints mobile manipulators under-actuated joints dynamic coupling

Lifetime Evaluating and the Effects of Operation Conditions on Automotive Fuel Cells

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Chinese Journal of Mechanical Engineering 2010年第1期23卷 66-71页

作者： PEI Pucheng yuan xing LI Pengcheng CHAO Pengxiang CHANG Qianfei State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing 100084 China School of Transportation Science and Engineering Beihang University Beijing 100191 China

Lifetime isone of the important indicators of automotive proton exchange membrane fuel cells. People used to evaluate the lifetime of vehicular fuel cells by laboratory tests or road tests that usually take thousands hours even years. In order to achieve a rapid evaluation technique and to seek lifetime extension methods, a lifetime calculation formation was drawn out in consideration of the vehicle driving cycle and the working condition factors. Bench experiments were individually carried out on two fuel-cell stacks same as ones applied on vehicle, and the performance decay rates of the two stacks were obtained under four operation conditions of changing load cycle, start-stop cycle, idling and heavy load. As a result, the predicted lifetimes rather conform to the actual running status in road test. And the research on the fuel cell performance decay rates under different load conditions was also done. Consequently, an unexpected finding was discovered that operating under micro-current has an effect on recovering fuel cell performance. The vehicle fuel cell rapid assessment method only requires four laboratory tests of driving cycle, load cycle, idle operating conditions and heavy load conditions, and the whole process merely lasts less than 250 h. These experimental results can be used to predict the vehicular fuel cell lifetimes on various utility models or driving cycles, therefore to optimize the application model to prolong the fuel cell lifetime. Actually in the experiment, it has already been proved successfully that the fuel cell lifetime could be extended from 1 100 h to 2 600 h by optimizing operating mode. The quick evaluation method is helpful to develop extended life fuel cell and to deplete fuel cell for a longer time.

关键词： Proton exchange membrane fuel cell fuel cell durability lifetime evaluating method operation conditions melioration.

Multiscale causes of the 2022 Yangtze mega-flash drought under climate change

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Science China Earth Sciences 2024年第8期67卷 2649-2660页

作者： xing yuan Yumiao WANG Shiyu ZHOU Hua LI Chenyuan LI School of Hydrology and Water Resources Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources Nanjing University of Information Science and TechnologyNanjing 210044China

The 2022 Yangtze mega-flash drought is characterized by strong intensity and rapid development both in time and space,accompanied by a persistent anticyclonic circulation ***,the causes of the extreme event remain elusive given the multiscale nature of *** we presented a brief overview for the oceanic and terrestrial causes of the megaflash drought during the summer of 2022,and estimated the risk in a changing *** the soil moisture percentile as the drought index,it was found that the drought expanded to the entire Yangtze River basin within two months,with 80%of basin under severe drought conditions at the end of *** the intensity and onset speed of the 2022 mega-flash drought were ranked as the first during the past 62 years,with return periods of 86 and 259 years,*** results of composite analysis showed that the spring La Ni?a can facilitate the abrupt change from a wet/normal condition in May–June to drought in July–August over the Yangtze River basin,which was beneficial for the increase of flash drought intensity and onset speed *** analysis through the linear regression also indicated that the unprecedented intensity was associated with the negative phase of the Pacific Decadal *** by a coupling strength index for soil moisture and vapor pressure deficit,it was found that there was a strong land-atmosphere coupling over the Yangtze River basin during July–August *** attribution by using CMIP6 climate models suggested that land-atmosphere coupling increased the risks of flash drought intensity and onset speed like 2022 by 61%±6%and 64%±7%under natural climate forcings,and the synergy of coupling and anthropogenic climate change would increase the risks by 75%±22%and 85%±12%.Our findings emphasized the role of landatmosphere coupling combined with anthropogenic climate change in intensifying flash droughts.

关键词： Flash drought Yangtze River basin Land-atmosphere coupling Climate change Attribution

Analysis of antibiotic resistance of Escherichia coli isolated from the Yitong River in North-east China

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Frontiers of Environmental Science & Engineering 2019年第3期13卷 127-135页

作者： Yangyang Yu Xiaolin Zhu Guanlan Wu Chengzhi Wang xing yuan School of Environment Northeast Normal University Changchun 130117 China

The Yitong River is one of the largest secondary tributaries of the Songhua River. The area where the Yitong River flows is densely populated and contains the livestock and poultry breeding areas of northeast China. These areas introduce a high risk of antibiotic contamination. In this study, the concentrations of four types of typical antibiotics including quinolones, tetracyclines, sulfonamides, and trimethoprim were determined by solid phase extraction-high performance liquid chromatography. The antibiotic resistance of Escherichia coli caused by antibiotic pollution was investigated. The concentration of total coliforms in the Yitong River was detected by the plate counting method. The antibiotic resistance of E. coli to quinolones, tetracyclines, sulfonamides, and trimethoprim was analyzed by the Kirby-Bauer method. The results showed that the concentration of total coliforms in the summer was higher than that in the spring. There was a seasonal difference in the resistance rate of E. coli to antibiotics except trimethoprim. The antibiotic resistance to fluoroquinolones was relatively low. The resistance rate to tetracyclines was higher during the summer. Moreover, resistance to several antibiotics was observed in all sections. This study provides basic data for research on pollution characteristics and prevention of antibiotic exposure in rivers.

关键词： Yitong River Coliform bacteria Antibiotic resistance Escherichia coli

Modifying glass fiber surface with grafting acrylamide by UV-grafting copolymerization for preparation of glass fiber reinforced PVDF composite membrane

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Journal of Environmental Sciences 2016年第1期28卷 208-217页

作者： Nan Luo Hui Zhong Min Yang xing yuan Yaobo Fan Group of Membrane Separation Technique Department of Water Pollution Control Technology Research Center for Eco-Environmental Sciences (RCEES) Chinese Academy of Sciences (CAS) State Key Joint Laboratory of Environmental Simulation and Pollution Control Research Center for Eco-Environmental Sciences (RCEES)Chinese Academy of Sciences (CAS)

Experimental design and response surface methodology（RSM） were used to optimize the modification of conditions for glass surface grafting with acrylamide（AM） monomer for preparation of a glass fiber reinforced poly（vinylidene fluoride）（PVDF） composite membrane（GFRP-CM）. The factors considered for experimental design were the UV（ultraviolet）-irradiation time, the concentrations of the initiator and solvent, and the kinds and concentrations of the silane coupling agent. The optimum operating conditions determined were UV-irradiation time of 25 min, an initiator concentration of 0–0.25 wt.%,solvent of N-Dimethylacetamide（DMAC）, and silane coupling agent KH570 with a concentration of 7 wt.%. The obtained optimal parameters were located in the valid region and the experimental confirmation tests conducted showed good accordance between predicted and experimental values. Under these optimal conditions, the water absorption of the grafted modified glass fiber was improved from 13.6% to 23%; the tensile strength was enhanced and the peeling strength of the glass fiber reinforced PVDF composite membrane was improved by 23.7% and 32.6% with an AM concentration at 1 wt.% and 2 wt.%. The surface composition and microstructure of AM grafted glass fiber were studied via several techniques including Field Emission Scanning Electron Microscopy（FESEM）, Fourier transform infrared spectroscopy-attenuated total reflectance（FTIR-ATR） and energy dispersive X-ray spectroscopy（EDX）. The analysis of the EDX and FTIR-ATR results confirmed that the AM was grafted to the glass fiber successfully by detecting and proving the existence of nitrogen atoms in the GFRP-CM.

关键词： Glass fibers Polymer-matrix composites Coupling agents UV-grafting copolymerization Interfacial strength

Causes and Predictability of the 2021 Spring Southwestern China Severe Drought

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Advances in Atmospheric Sciences 2022年第10期39卷 1766-1776页

作者： Yunyun LIU Zeng-Zhen HU Renguang WU xing yuan CMA Climate Studies Key Laboratory National Climate CenterChina Meteorological AdministrationBeijing 100081China Key Laboratory of Meteorological Disaster Ministry of Education&Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science&TechnologyNanjing 210044China Climate Prediction Center NCEP/NOAACollege ParkMaryland 20740USA School of Earth Sciences Zhejiang UniversityHangzhou 310058China School of Hydrology and Water Resources Nanjing University of Information Science and TechnologyNanjing 210044China

In the spring of 2021,southwestern China(SWC)experienced extreme drought,accompanied by the highest seasonal-mean temperature record since *** drought event occurred in the decaying phase of a La Niña event with negative geopotential height anomalies over the Philippine Sea,which is distinct from the historical ***,spring drought over SWC is often linked to El Niño and strong western North Pacific subtropical ***,we show that the extreme drought in the spring of 2021 may be mainly driven by the atmospheric internal variability and amplified by the warming ***,the evaporation increase due to the high temperature accounts for about 30%of drought severity,with the contributions of its linear trend portion being nearly 20%and the interannual variability portion being about 10%.Since the sea surface temperature forcing from the tropical central and eastern Pacific played a minor role in the occurrence of drought,it is a challenge for a climate model to capture the 2021 SWC drought beyond one-month lead times.

关键词： extreme spring drought Southwestern China precipitation evaporation warming trend internal variability predictability

Cage-confinement synthesis of MoC nanoclusers as efficient sulfiphilic and lithiophilic regulator for superior Li–S batteries

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Rare Metals 2024年第2期43卷 624-634页

作者： xing-yuan Zhang Mei-Na Lei Shan Tian Jian-Gan Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi’an710072China

High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite *** this work,a controllable cage-confinement strategy to fabricate molybdenum carbide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is *** sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li^(+) flux to suppress the lithium dendrite *** a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g^(−1) at a high rate of 5.0C and a small decay rate of 0.076%per cycle at 1.0C over 600 cycles are *** study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.

关键词： Li-S batteries Nanocluster Electrocatalyst Polysulfide shuttle Li dendrites

Synthesis and electromagnetic wave absorption properties of Gd-Co ferrite@carbon core-shell structure composites

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Rare Metals 2023年第1期42卷 254-262页

作者： Jing Gao Zhi-Jun Ma Fu-Li Liu xing-yuan Weng School of Mining Liaoning Technical UniversityFuxin123000China

Developing high-performance electromagnetic absorbing materials remains a *** this work,Gd-Co ferrite@carbon core-shell structure composites were synthesized by a two-step hydrothermal *** effects of rare earth Gd doping amount on the microstructure and electromagnetic wave absorption properties of cobalt ferrite@carbon composites were mainly *** results show that an appropriate amount of Gd doping can refine the crystal grain size of cobalt ferrite@carbon ***,when the doping amount of Gd exceeds the solid solubility threshold,the secondary phase GdFeO_(3)will be generated and the grain size will *** the doping amount of Gd is x=0.04,the reflection loss(RL) of the CoFe_(1.96)Gd_(0.04)O_(4)@C composites reaches the minimum value of -9.26 dB at the absorption layer thickness of 2.0 mm and a frequency of 13.67 GHz,and the effective absorption band(EAB) is 5.01 GHz(10.95-15.96 GHz).Compared with the CoFe_(2)O_(4)@C composites,the RL of the CoFe_(1.96)Gd_(0.04)O_(4)@C composites is increased by 79.35%,and the EAB is broadened by 3.51%.Gd ions enhance the dielectric loss through the grain size effect,and the increase of magnetocrystalline anisotropy enhances the magnetic *** CoFe_(1.96)Gd_(0.04)O_(4)@C composites have excellent impedance matching,which relies on the strong magnetic loss of ferrite,the interface polarization,and dipole polarization formed by the carbon shell to attenuate electromagnetic waves.

关键词： Rare earth Gd Cobalt ferrite Core-shell structure composites Electromagnetic wave absorption