Effect of TiO2 nanoparticle aggregation on marine microalgae Isochrysis galbana

TiO_2 nanoparticles(NPs) could adversely impact aquatic ecosystems. However, the aggregation of these NPs could attenuate this effect. In this work, the biological effects of TiO_2 NPs on a marine microalgae Isochrysis galbana were investigated. The aggregation kinetics of TiO_2 NPs under different conditions was also investigated to determine and understand these effects. Results showed that, though TiO_2 NPs had no obvious impact on the size and reproducibility of algal cells under testing conditions, they caused a negative effect on algal chlorophyll, which led to a reduction in photosynthesis. Furthermore, fast aggregation of TiO_2 NPs occurred under all conditions, especially at the pH close to the p Hzpc. Increasing ionic strength and NP concentration also enhanced the aggregation rate.The aggregation and the following sedimentation of TiO_2 NPs reduced their adverse effects on I. galbana.     

Relationship between physicochemical properties and dewaterability of hydrothermal sludge derived from different source

Sewage sludge (SS) and deinking sludge (DS) were used to comparatively study the hydrothermal dewatering of sludge with different components. For a better overview, an insight into the relationship between physicochemical properties and dewaterability of hydrothermal sludge was provided. Results found that not all kinds of sludge were suitably conditioned by hydrothermal treatment (HT) in term of the elevation of dewaterability. Higher hydrothermal temperature tended to enhance the dewaterability of SS rather than DS, which was supported by the variation of their physicochemical properties (including water distribution, bonding energy, extracellular polymeric substance (EPS), particles size, acid functional groups and zeta potential in this study). In addition, the changes in surface morphology suggested that the reverse effect of HT on sludge dewaterability was mainly due to their dewatering behavior. For SS, the destruction of EPS structure leaded to the release of bound water, thereby strengthening sludge dewatering. Conversely, “Bridging effect” generated by lignocellulose in DS was beneficial for sludge dewatering; however, the increasing hydrothermal temperature degraded part of lignocellulose and weakened “bridging effect”, finally resulting in worse dewaterability of DS.     

Regionalization based on spatial and seasonal variation in ground-level ozone concentrations across China

Owing to the vast territory of China and strong regional characteristic of ozone pollution,it's desirable for policy makers to have a targeted and prioritized regulation and ozone pollution control strategy in China based on scientific evidences. It's important to assess its current pollution status as well as spatial and temporal variation patterns across China.Recent advances of national monitoring networks provide an opportunity to insight the actions of ozone pollution. Here, we present rotated empirical orthogonal function(REOF)analysis that was used on studying the spatiotemporal characteristics of daily ozone concentrations. Based on results of REOF analysis in pollution seasons for 3 years' observations, twelve regions with clear patterns were identified in China. The patterns of temporal variation of ozone in each region were separated well and different from each other, reflecting local meteorological, photochemical or pollution features. A rising trend in annual averaged Eight-hour Average Ozone Concentrations(O_3-8 hr) from 2014 to 2016 was observed for all regions, except for the Tibetan Plateau. The mean values of annual and 90 percentile concentrations for all 338 cities were 82.6 ± 14.6 and 133.9 ± 25.8 μg/m~3,respectively, in 2015. The regionalization results of ozone were found to be influenced greatly by terrain features, indicating significant terrain and landform effects on ozone spatial correlations. Among 12 regions, North China Plain, Huanghuai Plain, Central Yangtze River Plain, Pearl River Delta and Sichuan Basin were realized as priority regions for mitigation strategies, due to their higher ozone concentrations and dense population.     

基于短时傅里叶变换的干扰信号识别方法

目的提高无线电引信识别欺骗式干扰的能力。方法根据炮弹弹体自旋的特点,使得采用连续波线极化天线的无线电引信所收到的干扰信号呈现出有别于地面回波的周期性幅度调制特征,通过对此特征进行短时傅里叶变换后进行识别,可以作为无线电引信是否受到欺骗式干扰的判断依据。结果通过仿真和试验对方法的可行性进行了验证,表明该识别方法可以很好地提高连续波无线电引信的识别欺骗式干扰的能力。结论基于短时傅里叶变换检测旋转调制的对地旋转弹无线电引信欺骗干扰识别的方法可以对干扰信号特征进行识别,算法处理时间短,能够作为引信是否受到干扰的一种判断依据。     

利用Rb/Sr值、有机碳氮同位素及14C重建贵州喀斯特地区古环境变化

本文利用碳酸盐岩风化剖面土壤中Rb/Sr值、有机碳氮的稳定同位素值(δ~(13)C_(org)和δ~(15)N_(org))并结合~(14)C定年结果,讨论了贵州黔西南喀斯特地区晚更新世以来的植被和气候变化情况。结果表明:(1)晚更新世以来,研究区气候在千年尺度上经历了多个冷热、干湿循环过程,植被以C4植物为主;(2)研究区在14 750 a BP时期可能发生过较为极端的气候事件;(3)Rb/Sr值和δ~(13)C_(org)值可以用来指示古环境变化情况,高Rb/Sr值和高δ~(13)C_(org)值指示湿热气候,低Rb/Sr值和低δ~(13)C_(org)值指示干冷气候。     

黔西南喀斯特地区红色风化壳的物源及元素迁移特征

南方喀斯特地区广泛分布着大量的红色风化壳,其成因及形成机制目前还存在争议。本文以贵州黔西南布依族苗族自治州泥凼石林的两处红色风化壳剖面(ND和YK)为研究对象,来探讨风化剖面上覆红土的物源问题,并计算其主、微量元素及稀土元素的迁移规律,认为本研究两处风化壳上覆红土为下伏基岩原位风化形成的,而且两剖面土壤均继承各自基岩的地球化学特征,并由于pH、风化强度等因素的影响表现出了元素迁移特征上的差异性。     

广东省生活垃圾焚烧设施环境与健康风险评估构架研究

生活垃圾焚烧设施的建立是解决城市生活垃圾逐年增多的有效方式之一,但其所引发的环境与健康问题成为公众关注的热点。基于广东省对生活垃圾焚烧设施的研究,以环境管理为目标,结合国内外在该领域的研究现状,提出广东省生活垃圾焚烧设施环境与健康风险评估构架。通过该构架的多年实践,总结了广东省生活垃圾焚烧设施环境与健康风险评估研究所取得的成效,有望将该成果推而广之,从而使该行业实现绿色生态的蓬勃发展。     

重庆九龙坡城区和城郊大气污染物浓度特征研究

为了解重庆市九龙坡区城区和城郊大气污染物浓度特征,分析了城区和城郊国控空气站点2014年3月~2015年2月典型污染物的浓度变化。结果表明,除O_3表现出夏高冬低的季节变化趋势外,其它污染物均表现出冬高夏低的季节变化趋势。PM_(2.5)污染最严重,城区和郊区日均值超标率分别为31.4%和33.4%。城区和城郊的PM_(2.5)浓度之间没有显著性差异(p0.05),城郊O_3浓度显著高于城区(p0.01),NO_2、SO_2、CO和PM_(10)则是城区显著高于城郊(p0.01)。     

雾霾环境天气下对户外体育运动人群影响研究

构建雾霾环境天气下户外体育运动生理健康指标参数,以最大摄氧量(VO2)、最大通气量(VEmax)、氧脉搏O2P、心率(HR)等参量为约束指标,构建户外体育运动人群身体健康指标的约束体系,采用心电图的负荷试验和代谢分析实验方法测试雾霾环境天气下对户外体育运动人群健康影响,根据受测运动员的气体代谢和心肺功能指标进行雾霾环境天气下运动人群的心肺机能特征分析。雾霾环境天气下,应当减少户外运动,在空气质量好的环境下进行一定的有氧运动,避免吸入污染空气,导致肺部疾病。     

基于环境保护大数据的监测与智能诊断研究

为了提高环境保护的智能监测能力,采用大数据分析方法进行环境监测和诊断分析,提出一种基于环保大数据关联特征挖掘的环境保护智能监测与诊断技术。构建环境监测的约束参量模型,以土壤监测数据、空间污染排放量以及水资源监测数据为原始统计数据,采用关联规则特征提取方法进行环保大数据的有用信息挖掘,结合模糊C均值聚类算法实现对环保大数据的分类处理,根据分类结果进行环保监测和智能诊断分析。仿真结果表明,采用该方法进行环保大数据挖掘的准确性较好,对各种污染信息的分类精度较高,提高了环保监测和诊断的有效性与实时性。