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7篇 您的检索式:作者名="Yunchen Zhang"
    题名 作者 年代 出处 被引量
1Observation and analysis of atmospheric volatile organic compounds in a typical petrochemical area in Yangtze River Delta, China显示文摘Volatile organic compounds(VOCs) are a kind of important precursors for ozone photochemical formation. In this study, VOCs were measured from November 5 th, 2013 to January 6 th, 2014 at the Second Jinshan Industrial Area, Shanghai, China. The results showed that the measured VOCs were dominated by alkanes(41.8%), followed by aromatics(20.1%), alkenes(17.9%), and halo-hydrocarbons(12.5%). The daily trend of the VOC concentration showed a bimodal feature due to the rush-hour traffic in the morning and at nightfall. Based on the VOC concentration, a receptor model of Positive Matrix Factorization(PMF) coupled with the information related to VOC sources was applied to identify the major VOC emissions. The result showed five major VOC sources: solvent use and industrial processes were responsible for about 30% of the ambient VOCs, followed by rubber chemical industrial emissions(23%), refinery and petrochemical industrial emissions(21%), fuel evaporations(13%) and vehicular emissions(13%). The contribution of generalized industrial emissions was about 74% and significantly higher than that made by vehicle exhaust. Using a propylene-equivalent method, alkenes displayed the highest concentration, followed by aromatics and alkanes. Based on a maximum incremental reactivity(MIR)method, the average hourly ozone formation potential(OFP) of VOCs is 220.49 ppbv. The most significant source for ozone chemical formation was identified to be rubber chemical industrial emissions, following one by vehicular emission. The data shown herein may provide useful information to develop effective VOC pollution control strategies in industrialized area.Yunchen Zhang Rui Li Hongbo Fu Dong Zhou Jianmin Chen 2018Journal of Environmental Sciences2018,30,9:21
2Conjugated polymer-mediated synthesis of sulfur- and nitrogen-doped carbon nanotubes as efficient anode materials for sodium ion batteries显示文摘Yanzhen He Xijiang Han Yunchen Du Bo Song Bin Zhang Wei Zhang Ping Xu 2018Nano Research2018,11,5:4
3Individual particle analysis of aerosols collected at Lhasa City in the Tibetan Plateau显示文摘To understand the composition and major sources of aerosol particles in Lhasa City on the Tibetan Plateau(TP), individual particles were collected from 2 February to 8 March, 2013 in Tibet University. The mean concentrations of both PM2.5and PM10 during the sampling were25.7 ± 21.7 and 57.2 ± 46.7 μg/m3, respectively, much lower than those of other cities in East and South Asia, but higher than those in the remote region in TP like Nam Co, indicating minor urban pollution. Combining the observations with the meteorological parameters and back trajectory analysis, it was concluded that local sources controlled the pollution during the sampling. Transmission electron microscopy(TEM) combined with energydispersive X-ray spectra(EDS) was used to study 408 particles sampled on four days. Based on the EDS analysis, a total of 8 different particle categories were classified for all 408 particles, including Si-rich, Ca-rich, soot, K-rich, Fe-rich, Pb-rich, Al-rich and other particles.The dominant elements were Si, Al and Ca, which were mainly attributed to mineral dust in the earth's crust such as feldspar and clay. Fe-, Pb-, K-, Al-rich particles and soot mainly originated from anthropogenic sources like firework combustion and biomass burning during the sampling. During the sampling, the pollution mainly came from mineral dust,while the celebration ceremony and religious ritual produced a large quantity of anthropogenic metal-bearing particles on 9 and 25 February 2013. Cement particles also had a minor influence. The data obtained in this study can be useful for developing pollution control strategies.Bu Duo Yunchen Zhang Lingdong Kong Hongbo Fu Yunjie Hu Jianmin Chen Lin Li A.Qiong 2015Journal of Environmental Sciences2015,27,3:4
4Reduced graphene oxide aerogel decorated with Mo_(2)C nanoparticles toward multifunctional properties of hydrophobicity,thermal insulation and microwave absorption显示文摘Reduced graphene oxide(rGO)aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials(EWAMs)due to their intrinsic conductive networks and intricate interior microstructure,as well as good compatibility with other electromagnetic(EM)components.Herein,we realized the decoration of rGO aerogel with Mo_(2)C nanoparticles by sequential hydrothermal assembly,freeze-drying,and high-temperature pyrolysis.Results show that Mo_(2)C nanoparticle loading can be easily controlled by the ammonium molybdate to glucose molar ratio.The hydrophobicity and thermal insulation of the rGO aerogel are effectively improved upon the introduction of Mo_(2)C nanoparticles,and more importantly,these nanoparticles regulate the EM properties of the rGO aerogel to a large extent.Although more Mo_(2)C nanoparticles may decrease the overall attenuation ability of the rGO aerogel,they bring much better impedance matching.At a molar ratio of 1:1,a desirable balance between attenuation ability and impedance matching is observed.In this context,the Mo_(2)C/r GO aerogel displays strong reflection loss and broad response bandwidth,even with a small applied thickness(1.7 mm)and low filler loading(9.0wt%).The positive effects of Mo_(2)C nanoparticles on multifunctional properties may render Mo_(2)C/r GO aerogels promising candidates for high-performance EWAMs under harsh conditions.Yahui Wang Minghui Zhang Xuesong Deng Zhigang Li Zongsheng Chen Jiaming Shi Xijiang Han Yunchen Du 2023International Journal of Minerals,Metallurgy and Materials2023,30,3:2
5Ordered mesoporous silica materials (SBA-15) with good heat-resistant magnetism显示文摘Yunchen Du Sen Liu Yanyan Ji Yonglai Zhang Ni Xiao Feng-Shou Xiao 2008Journal of Magnetism and Magnetic Materials2008,,:1
6Magnetic field‐enhanced water splitting enabled by bifunctional molybdenum‐doped nickel sulfide on nickel foam显示文摘Herein,we report bifunctional molybdenum-doped nickel sulfide on nickel foam(Mo-NiS_(x)/NF)for magnetic field-enhanced overall water splitting under alkaline conditions.Proper doping of Mo can lead to optimization of the electronic structure of NiS_(x),which accelerates the dissociation of H2O and the adsorption of OH−in the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)processes,respectively.In addition,the magnetically active Mo-NiS_(x)/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic(FM)exchange-field penetration effect.As a result,Mo-NiS_(x)/NF requires low overpotentials of 307 mV at 50mA cm^(−2)(for OER)and 136 mV at 10mA cm^(−2)(for HER)under a magnetic field of 10000 G.Furthermore,the electrolytic cell constructed by the bifunctional Mo-NiS_(x)/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm^(−2)with optimal stability over 60 h under the magnetic field.Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.Yuanyuan Zhang Mengxin Chen Ping Guo Yunchen Du Bo Song Xianjie Wang Zaixing Jiang Ping Xu 2023Carbon Energy2023,5,10:0
7Underwater Sea Cucumber Target Detection Based on Edge-Enhanced Scaling YOLOv4显示文摘Sea cucumber detection is widely recognized as the key to automatic culture.The underwater light environment is complex and easily obscured by mud,sand,reefs,and other underwater organisms.To date,research on sea cucumber detection has mostly concentrated on the distinction between prospective objects and the background.However,the key to proper distinction is the effective extraction of sea cucumber feature information.In this study,the edge-enhanced scaling You Only Look Once-v4(YOLOv4)(ESYv4)was proposed for sea cucumber detection.By emphasizing the target features in a way that reduced the impact of different hues and brightness values underwater on the misjudgment of sea cucumbers,a bidirectional cascade network(BDCN)was used to extract the overall edge greyscale image in the image and add up the original RGB image as the detected input.Meanwhile,the YOLOv4 model for backbone detection is scaled,and the number of parameters is reduced to 48%of the original number of parameters.Validation results of 783images indicated that the detection precision of positive sea cucumber samples reached 0.941.This improvement reflects that the algorithm is more effective to improve the edge feature information of the target.It thus contributes to the automatic multi-objective detection of underwater sea cucumbers.Ziting Zhang Hang Zhang Yue Wang Tonghai Liu Yuxiang He Yunchen Tian 2023Journal of Beijing Institute of Technology2023,32,3:0
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