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保定市PM_(2.5)中水溶性离子污染特征及来源分析 被引量:5
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作者 武志宏 孙爽 +3 位作者 武高峰 姜建芳 刘爽 赵文吉 《环境化学》 CAS CSCD 北大核心 2021年第5期1421-1430,共10页
为研究保定市PM_(2.5)中水溶性离子污染特征及来源,利用中流量采样器采集保定市2017年秋、冬季10月—2017年12月污染天的PM_(2.5)样品(40个),进行水溶性离子组分分析,并辅以保定市同期气象数据及空气质量数据进行成因探讨。计算离子间... 为研究保定市PM_(2.5)中水溶性离子污染特征及来源,利用中流量采样器采集保定市2017年秋、冬季10月—2017年12月污染天的PM_(2.5)样品(40个),进行水溶性离子组分分析,并辅以保定市同期气象数据及空气质量数据进行成因探讨。计算离子间相关性,采用离子平衡法衡量大气酸碱度,并对保定市日夜不同时段PM_(2.5)中水溶性离子污染特征进行细节分析,并利用主成分分析法分析PM_(2.5)中水溶性离子来源,且对二次离子来源及气象条件影响进行了深入分析。根据离子之间相关性,推测保定市K^(+)和NO_(3)^(-)、Cl^(−)具有同源性,主要源于生物质燃烧;NH+4在大气中主要以NH_(4)NO_(3)、(NH_(4))_(2)SO_(4)及NH_(4)HSO_(4)等形式存在;推测NO_(3)^(-)及SO_(4)^(2−)两离子主要来源均为工业排放污染物的化学转化;保定市非采暖期大气颗粒物呈酸性,采暖期大气颗粒物呈现碱性。多数水溶性离子含量均呈现夜间高于白天的现象,这一现象可能与气象变化及周围环境影响等诸多因素有关;污染天和清洁天大气PM_(2.5)中二次离子主要来源于移动源;二次离子与湿度均呈正相关趋势,而SO_(4)^(2−)与温度呈负相关趋势;水溶性离子浓度高低依次为NO_(3)^(-)>Na^(+)>SO_(4)^(2−)>Cl^(−)>NH_(4)^(+)>NO_(2)^(-)>Ca^(2+)>K^(+)>F^(−)>Mg^(2+),10—12月PM_(2.5)中多数水溶性离子含量均呈现夜间高于白天的现象;采暖季SOR、NOR均低于非采暖季,二次污染物转化效率较低,这可能与采暖季煤燃烧释放污染物有关;保定市PM_(2.5)水溶性离子主要来源为生物质燃烧、化石燃料燃烧及扬尘源及二次源。 展开更多
关键词 PM_(2.5) 水溶性离子 PCA SNA 气象因素
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Iron Species-Impregnated Granular Activated Carbon as Modified Particle Electrodes Applied in Benzothiazole Adsorption and Electrocatalytic Degradation 被引量:2
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作者 jie ding dihui song +2 位作者 xianshu liu zhao song gaofeng wu 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2017年第3期39-49,共11页
The object of this study is to prepare iron species-impregnated granular activated carbon as particle electrodes in order to improve their adsorption and electrocatalytic degradation capacity in Benzothiazole removal.... The object of this study is to prepare iron species-impregnated granular activated carbon as particle electrodes in order to improve their adsorption and electrocatalytic degradation capacity in Benzothiazole removal.The incorporation of Fe-containing catalysts was performed by Fe(NO_3)_3 impregnation.The obtained samples were characterized by BET,Fourier transform infrared spectroscopy,SEM-EDS,powder X-ray diffraction,X-ray photoelectron spectra and TG.Compared with pure activated carbon,this modified particle electrodes show higher static adsorption capacities and TOC removal,which have respectively increased by25.9% and 54.4%.Both physisorption and chemisorption exist in the process of benzothiazole adsorption,where the latter plays a major role.In this way,the Fe-containing catalysts on modified particle electrodes are demonstrated to make a greater contribution to the improvement of electrocatalytic degradation by decreasing the activated energy by 32%. 展开更多
关键词 MODIFIED ACTIVATED carbon iron particle electrodes BENZOTHIAZOLE ADSORPTION ELECTROCATALYTIC degreadation
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Mobility control of unmanned aerial vehicle as communication relay in airborne multi-user systems 被引量:5
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作者 gaofeng wu Xiaoguang GAO +2 位作者 Xiaowei Fu Kaifang WAN Ruohai DI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第6期1520-1529,共10页
In this paper, a model-based adaptive mobility control method for an Unmanned Aerial Vehicle(UAV) acting as a communication relay is presented, which is intended to improve the network performance in airborne multi-us... In this paper, a model-based adaptive mobility control method for an Unmanned Aerial Vehicle(UAV) acting as a communication relay is presented, which is intended to improve the network performance in airborne multi-user systems. The mobility control problem is addressed by jointly considering unknown Radio Frequency(RF) channel parameters, unknown multi-user mobility, and non-available Angle of Arrival(AoA) information of the received signal. A Kalman filter and a least-square-based estimation algorithm are used to predict the future user positions and estimate the RF channel parameters between the users and the UAV, respectively. Two different relay application cases are considered: end-to-end and multi-user communications. A line search algorithm is proposed for the former, with its stability given and proven, whereas a simplified gradient-based algorithm is proposed for the latter to provide a target relay position at each decision time step, decreasing the two-dimensional search to a one-dimensional search. Simulation results show that the proposed mobility control algorithms can drive the UAV to reach or track the optimal relay position movement, as well as improving network performance. The proposed method reflects the properties of using different metrics as objective network performance functions. 展开更多
关键词 Channel estimation GRADIENT methods MOTION control Optimization RELAY Unmanned AERIAL vehicle WIRELESS networks
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