城市湿地损失和内涝灾害响应的遥感分析——以武汉市南湖为例

随着快速的城市化，城市湿地不断转化成建设用地，这打破了城市水量循环的均衡，城市内涝灾害的敏感性和危害性随之提高。选取城市快速扩张的武汉市南湖地区，基于1988～2015年近30 a南湖湿地多时相遥感影像，以武汉市南湖2016年7月内涝灾害为对象，运用遥感和GIS手段，分析南湖湿地损失过程、驱动因素以及城市涝灾害的响应情况。结果表明：（1）1988~2015年间南湖湿地持续损失，累计消减1 563 hm2；南湖湿地损失经历了快速损失（1988~1996）急剧损失（1996~2004）缓慢损失（1996~2010）相对静止（2010~2015）的4个阶段，每个阶段南湖湿地转化为建设用地量分别为35.3、135、30、5.4 hm2；损失过程从南湖湿地北部开始，逐渐向南部蔓延；（2）环湖地区房地产发展是湖泊湿地损失的主要原因,52%的损失湿地转换为住宅用地；（3）85.7%的内涝灾害区域位于原湖泊湿地内；南湖地区海拔较低，随着住宅用地以及其他建设用地对湖泊湿地的侵占，南湖地区不透水面面积增加，湿地蓄水排水能力下降，在降雨量较多的时段，原湖泊湿地区域更容易受到内涝侵袭。 关键词： 城市湿地; 湿地损失; 内涝灾害; 武汉市南湖     

Dissipation kinetics and residues of triazolopyrimidine herbicides flumetsulam and florasulam in corn ecosystem

The dynamic and residues of florasulam and flumetsulam in corn field ecosystem were investigated using quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The limits of quantification (LOQs) of the proposed method ranged from 0.005 to 0.01 mg/kg. Mean recoveries and relative standard deviations (RSDs) of the two compounds in all samples at three spiking levels ranged 94–110 % and 2.0–9.2 %, respectively. Florasulam and flumetsulam degradation followed first-order kinetics with half-lives 1.7–2.9 and 3.3–8.7 days in soil and 1.3–1.8 and 0.9–1.7 days in plant, respectively. The residues in all the samples were found to be less than the LOQs at preharvest intervals of 53 and 78 days. The results suggest that the combined use of florasulam and flumetsulam on corn is considered to be safe under the recommended conditions and can be utilized for establishing the maximum residue limit (MRL) of florasulam in corn in China.     

江苏省2014-2016年臭氧污染区域特征分析

分析2014—2016年江苏省O₃污染状况，以及苏北、苏中和苏南3个典型区域O₃年度、季度、日变化和频度占比等分布特征。结果表明，江苏省的O₃空间分布呈现北低南高，2014—2016年的O₃超标占比由18.4%上升至34.9%；2016年苏北、苏中和苏南地区O₃-8h第90百分位数与2014年相比，上升2.7%，21.8%和3.3%；3个区域夏季O₃-8h均值最高，春、秋2季次之，冬季最低；O₃-1h日变化呈单峰状态，最低值出现在06:00—07:00，最高值出现在15:00—16:00；2016年3个地区的O₃频度占比均呈正态分布，主要集中在40~80 μg/m³，所占比例均>15%；苏中和苏南区域2016和2014年相比O₃频率占比的变化幅度较大，苏北地区变化幅度不大。指出，江苏省的O₃污染程度在逐年提高，污染范围从苏南逐渐往中部和北部城市扩大。     

Impact of green credit on industrial structure in China: theoretical mechanism and empirical analysis

Environmental Science and Pollution Research - Chinese industrial structure is characterized by a large proportion of industries with high energy consumption and high pollution, such as coal,...     

The toxicity of cadmium ion (Cd2+) to phycocyanin: an in vitro spectroscopic study

Environmental Science and Pollution Research - The pollution of heavy metals is a severer problem for the ecosystems in waters. The toxicity of Cd2+ on phycocyanin (PC) is studied in molecular...     

一起110kV电容式电压互感器缺陷分析

电容式电压互感器(capacitor voltage transformer,CVT),是变电站的重要设备,主要用来测量线路电压,为二次设备提供电源等。通过对一起某变电站 110kV电容式电压互感器异常发热缺陷分析,结合电气试验、油色谱检测等,对缺陷部位和原因进行诊断,并提出了相应的防范措施。     

基于BERT-BILSTM-CRF模型的电力行业事故文本智能分析*

为解决电力行业事故报告文本较长、语义复杂,难以进行有效文本识别问题,提出1种以BERT作为底层的预训练模型,并设计1种双重注意力机制编码器,结合BILSTM-CRF深度挖掘事故文本语义特征,从而实现文本智能分析。首先构建电力词典,通过对BERT预训练,进行BIO标注,然后引入BILSTM-CRF模型实现对文本标签智能分类,最后将该模型与现行其他4种深度学习模型进行对比。研究结果表明:该模型智能识别精确率、召回率及F1值(查准率)均达到约97%,较其他4种模型中效果最好的模型分别提高0.02,0.03,0.02。研究结果可为电力行业事故报告文本分析提供1种新思路。     

农村生活污水处理技术的应用效果及其经济性分析研究——以重庆地区为例

为了解农村生活污水处理技术在应用过程中的效果.以重庆地区为例,对重庆市63个村庄的生活污水处理设施进行了调查.根据出水水质和建设成本,对村庄常用的污水处理技术进行经济技术综合比较分析.结果表明,无动力人工湿地较为经济,应用效果并不理想,在经济条件比较薄弱的地区可作为过渡型处理技术加以应用;渠道式生态沟投资较昂贵,不推荐使用;一体化设备投资昂贵,运行管理简单,在经济条件较好的地区可以考虑使用.     

宝鸡市经济增长与环境空气综合污染指数关系研究

文章以空气综合污染指数法分析了宝鸡市2006年-2011年的环境空气质量状况,分析结果表明宝鸡市环境空气质量逐年变好。以人均GDP为经济指标,以空气综合污染指数为环境指标,建立经济增长与环境空气质量之间的计量模型,进行环境库兹涅茨曲线实证研究。研究结果表明,宝鸡市经济增长和环境空气质量的关系符合库兹涅茨曲线"拐点"后的下降部分。证明该市2006年-2011年的环境空气质量与人均GDP处于良性发展状态。     

Fast increasing of surface ozone concentrations in Pearl River Delta characterized by a regional air quality monitoring network during 2006-2011

Based on the observation by a Regional Air Quality Monitoring Network including 16 monitoring stations, temporal and spatial variations of ozone(O3), NO2and total oxidant(Ox) were analyzed by both linear regression and cluster analysis. A fast increase of regional O3concentrations of 0.86 ppbV/yr was found for the annual averaged values from 2006 to 2011 in Guangdong, China. Such fast O3increase is accompanied by a correspondingly fast NOx reduction as indicated by a fast NO2 reduction rate of 0.61 ppbV/yr. Based on a cluster analysis, the monitoring stations were classified into two major categories – rural stations(non-urban) and suburban/urban stations. The O3concentrations at rural stations were relatively conserved while those at suburban/urban stations showed a fast increase rate of 2.0 ppbV/yr accompanied by a NO2 reduction rate of 1.2 ppbV/yr. Moreover, a rapid increase of the averaged O3 concentrations in springtime(13%/yr referred to 2006 level) was observed, which may result from the increase of solar duration, reduction of precipitation in Guangdong and transport from Eastern Central China. Application of smog production algorithm showed that the photochemical O3production is mainly volatile organic compounds(VOC)-controlled. However, the photochemical O3production is sensitive to both NOx and VOC for O3pollution episode. Accordingly, it is expected that a combined NOx and VOC reduction will be helpful for the reduction of the O3 pollution episodes in Pearl River Delta while stringent VOC emission control is in general required for the regional O3 pollution control.