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Observation and analysis of atmospheric volatile organic compounds in a typical petrochemical area in Yangtze River Delta, China

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Journal of Environmental Sciences 2018年第9期30卷 233-248页

作者： Yunchen Zhang Rui Li Hongbo Fu Dong Zhou Jianmin Chen Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science & Engineering Fudan University Shanghai 200433 China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092 China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET) Nanjing University of Information Science and Technology Nanjing 210044 China

Volatile organic compounds （VOCs） are a kind of important precursors for ozone photochemical formation. In this study, VOCs were measured from November 5th, 2013 to January 6th, 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 concentra-tion, 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.

关键词： VOCs PMF Emission sources Photochemical reactivity MIR OFP

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Underwater Sea Cucumber Target Detection Based on Edge-Enhanced Scaling YOLOv4

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Journal of Beijing Institute of Technology 2023年第3期32卷 328-340页

作者： Ziting zhang Hang zhang Yue Wang Tonghai Liu Yuxiang He yunchen Tian College of Computer and Information Engineering Tianjin Agricultural UniversityTianjin 300380China

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.

关键词： sea cucumber edge extraction feature enhancement edge-enhanced scaling You Only Look Once-v4(YOLOv4)(ESYv4) model scaling

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Reduced graphene oxide aerogel decorated with Mo_(2)C nanoparticles toward multifunctional properties of hydrophobicity,thermal insulation and microwave absorption

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International Journal of Minerals,Metallurgy and Materials 2023年第3期30卷 536-547页

作者： Yahui Wang Minghui zhang Xuesong Deng Zhigang Li Zongsheng Chen Jiaming Shi Xijiang Han yunchen Du Key Laboratory of Infrared and Low Temperature Plasma of Anhui Province National University of Defense TechnologyHefei 230037China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China State Key Laboratory of Pulsed Power Laser Technology National University of Defense TechnologyHefei 230037China Anhui Provincial Laboratory of Advanced Laser Technology National University of Defense TechnologyHefei 230037China

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.

关键词： Mo_(2)C/reduced graphene oxide aerogel microwave absorption dielectric loss hydrophobicity thermal insulation

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Individual particle analysis of aerosols collected at Lhasa City in the Tibetan Plateau

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Journal of Environmental Sciences 2015年第3期27卷 165-177页

作者： Bu Duo Yunchen Zhang Lingdong Kong Hongbo Fu Yunjie Hu Jianmin Chen Lin Li A.Qiong Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science & EngineeringFudan University Department of Chemistry & Environmental Science Tibet University Environmental Monitoring Center Station of Tibet Autonomous Region

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 PM2.5 and PM10 during the sampling were 25.7 ± 21.7 and 57.2 ± 46.7 μg/m^3, 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, A1 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 anthro- pogenic 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.

关键词： Individual particles Fireworks Biomass burning Lhasa TEM

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Conjugated polymer-mediated synthesis of sulfur- and nitrogen-doped carbon nanotubes as efficient anode materials for sodium ion batteries

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Nano Research 2018年第5期11卷 2573-2585页

作者： Yanzhen He Xijiang Han yunchen Du Bo Song Bin zhang Wei zhang Ping Xu MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin 150001 China Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing 400714 China

Heteroatom-doped carbon nanomaterials have attracted significant attention as anode materials for sodium-ion batteries （SIBs）. Herein, we demonstrate a conjugated polymer-mediated synthesis of sulfur and nitrogen co-doped carbon nanotubes （S/N-CT） via the carbonization of sulfur-containing polyaniline （PANI） nanotubes. It is found that the carbonization technique greatly influences the structural features and thus the Na-storage behavior of the S/N-CT materials. The carbon nanotubes developed using a two-step carbonization process （heating at 400℃ and then at 900℃） exhibit a high specific surface area, enlarged interlayer distance, small charge transfer resistance, enhanced reaction kinetics, as well as a large number of defects and active sites; further, they exhibit a high reversible capacity of 340 mAh·g^-1 at 0.1 A·g^-1 and a remarkable cycling stability with a capacity of 141 mAh·g^-1 at 5 A·g^-1 （94% retention after 3,000 cydes）. Direct carbonization of conjugated polymers with a specific morphology is an eco-friendly and low-cost technique for the synthesis of dual atom-doped carbon nanomaterials for application in energy devices. However, the carbonization process should be carefully controlled in order to better tune the structure-property relationship.

关键词： sodium ion battery,conjugated polymer,carbon nanotube,heteroatom doping

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Magnetic field‐enhanced water splitting enabled by bifunctional molybdenum‐doped nickel sulfide on nickel foam

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Carbon Energy 2023年第10期5卷 50-63页

作者： Yuanyuan zhang Mengxin Chen Ping Guo yunchen Du Bo Song Xianjie Wang Zaixing Jiang Ping Xu MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbinChina School of Physics Harbin Institute of TechnologyHarbinChina

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.

关键词： electron density modulation FM exchange‐field penetration effect magnetic field magnetoresistance effect water splitting

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马尼拉大帆船贸易垄断体制的建立及评价

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国际汉学 2021年第4期 28-43,198,199页

作者：韩琦张昀辰南开大学世界近现代史研究中心南开大学拉美研究中心

马尼拉大帆船贸易是菲律宾殖民当局的生命线。1565年菲律宾与新西班牙的贸易航线开通之后,一度沟通了中国经过菲律宾与美洲的自由贸易。但是由于这种贸易冲击了宗主国西班牙原先在美洲的贸易,且导致美洲白银流向亚洲,同时又不利于菲律... 详细信息

马尼拉大帆船贸易是菲律宾殖民当局的生命线。1565年菲律宾与新西班牙的贸易航线开通之后,一度沟通了中国经过菲律宾与美洲的自由贸易。但是由于这种贸易冲击了宗主国西班牙原先在美洲的贸易,且导致美洲白银流向亚洲,同时又不利于菲律宾当地工农业的发展,因此,从1593年开始,西班牙便颁布了一系列法令,除了对与中国的贸易做出种种规定之外,还从航行的次数、载重量、价值额、关税数额等方面对大帆船贸易进行限制,实行特许经营权制度、许可额制度、整批交易制度、货票制度、关税制度等,这样,便逐渐形成了一整套贸易垄断体制。垄断贸易在短期内维持了殖民地内部的贸易平衡,但从长期看,不利于菲律宾经济的发展,它带来的种种弊端,加上其他西方国家的挑战,最终导致大帆船贸易的终结。

关键词：马尼拉大帆船贸易贸易垄断体制太平洋丝绸之路菲律宾群岛西班牙新西班牙

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染料敏化太阳电池准固态电解质光电功能的优化分析

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太阳能学报 2017年第10期38卷 2827-2832页

作者：马海斌张运臣潍坊学院化学化工与环境工程学院潍坊261061

通过对准固态电解质的内部微观结构的分析,阐述准固态电解质的微观结构对其光电功能(光功能和电功能)特性的影响,及其对染料敏化太阳电池(DSSC)光伏性能的影响。研究表明:基于向列相液晶4-氰基-4'-庚氧基联苯的准固态电解质中,其三维网... 详细信息

通过对准固态电解质的内部微观结构的分析,阐述准固态电解质的微观结构对其光电功能(光功能和电功能)特性的影响,及其对染料敏化太阳电池(DSSC)光伏性能的影响。研究表明:基于向列相液晶4-氰基-4'-庚氧基联苯的准固态电解质中,其三维网状结构的尺寸处于亚微米级,且网孔尺寸较大,具有较好的光散射功能并有利于离子的传输,能够显著提高DSSC中染料的光吸收,提高准固态DSSC的光电流密度。

关键词：染料敏化太阳电池(DSSC) 电解质光电功能三维网状结构

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20世纪80年代以来阿根廷的城市化转型与问题治理

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世界近现代史研究 2020年第2期 237-257,318,319页

作者：张昀辰南开大学世界近现代史研究中心南开大学拉美中心

20世纪80年代以来,阿根廷城市化进程进入新的转型期。伴随国际与国内经济形势的变化,该时期城市化的主要特点是城市人口主要流动方式由乡村—城市流动向城市间流动转变,同时形成了非正规城市就业率居高不下、贫困率上升、城市空间隔离... 详细信息

20世纪80年代以来,阿根廷城市化进程进入新的转型期。伴随国际与国内经济形势的变化,该时期城市化的主要特点是城市人口主要流动方式由乡村—城市流动向城市间流动转变,同时形成了非正规城市就业率居高不下、贫困率上升、城市空间隔离加深等问题。20世纪90年代新自由主义改革时期的政治经济政策在一定程度上加剧了这些问题。进入21世纪后,对城市问题的整顿受到阿根廷政府的重视,在20年中,政府出台了提高城市社会保障水平、改善城市基础设施等方面的政策,取得了一定成果。但城市化面临的挑战仍很艰巨,推动城市的可持续发展还有待长期且有效的治理。

关键词：阿根廷城市化转型城市问题城市治理

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拉丁美洲城市化历史的研究综述

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世界近现代史研究 2018年第1期 189-204,366,367页

作者：张昀辰南开大学世界近现代史研究中心

对于拉丁美洲城市化的研究,国内外学术论著层出不穷。国内学者的研究主要集中在城市化进程、经济发展与人口流动、城市化问题等方面。而国外学者的研究则呈现出了研究角度和研究方法的多样性,本文以“殖民地时期城市发展史的研究”和“... 详细信息

对于拉丁美洲城市化的研究,国内外学术论著层出不穷。国内学者的研究主要集中在城市化进程、经济发展与人口流动、城市化问题等方面。而国外学者的研究则呈现出了研究角度和研究方法的多样性,本文以“殖民地时期城市发展史的研究”和“独立后至20世纪中期城市化史的研究”为题,分两个历史时段,介绍了国外学者对拉美城市发展进程、工业化与城市化、人口流动与城市空间布局、城市发展的差异等问题的研究概况,并期望通过回顾拉美城市历史研究的学术史,推动中国学界对拉美城市史的研究,为中国的城市化提供经验借鉴。

关键词：拉丁美洲城市史城市化工业化非正规住房

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