排序方式: 共有21条查询结果,搜索用时 15 毫秒
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Zhiqiao He Qiaolan Cai Huiying Fang Gaohua Situ Jianping Qiu Shuang Song Jianmeng Chen 《环境科学学报(英文版)》2013,25(12):2460-2468
A series of TiO2 with different crystal phases and morphologies was synthesized via a facile hydrothermal process using titanium nbutoxide and concentrated hydrochloric acid as raw materials. The photocatalytic activity of the samples was evaluated by degradation of Methyl Orange in aqueous solution under UV-Visible light irradiation. On the basis of detailed analysis of the characterizing results of high-resolution transmission electron microscopy, X-ray powder diffraction measurements, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller measurement, it was concluded that the photo-activity of the catalyst is related directly to the 3D morphology and the crystal phase composition. An excellent catalyst should have both a futile 3D flower-like structure and anatase granulous particles. The 3D flower-like structure could enhance light harvesting, as well as the transfer of reactant molecules from bulk solution to the reactive sites on TiO2. In addition, the optimum anatase/rutile phase ratio was found to be 80:20, which is beneficial to the effective separation of the photogenerated electron-hole pairs. 相似文献
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基于高斯扩散的单源估算模式SCREEN3计算佛山市环境统计企业的SO2排放最大落地浓度距离,发现全市工业企业SO2排放最大落地浓度距离为0.4~13.5 km.其中水泥和火电等高架源的最大落地浓度的距离最远.佛山市及五区纳入环境统计的重点废气排放企业平均的SO2排放最大落地浓度距离为2.9~4.9 km,能直接影响国控监测点位的企业合计37家,其中40%为高明区的企业.该结果证明加强空气质量国控监测点位周边至少5 km内废气排放企业的督查有利于空气质量的改善. 相似文献
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在淀山湖0.5、1.0、1.5、2.0 m水层进行苦草(Vallisneria natans)现场生长实验,试图找出淀山湖苦草植被恢复的适宜环境条件。试验期间每天测量光照强度和水体溶解氧等环境因子,每隔10 d监测苦草的根长、株高、鲜重等生长指标的变化情况。结果表明:水深对苦草的生长具较显著影响,光照强度、溶氧分别和苦草日相对生长率具显著相关性;苦草的株高、叶片数、根长等生物学生长指标在0.5、1.0 m水层生长良好,1.5 m与2.0 m均出现不同程度的负增长状况。光照强度与苦草日相对生长率之间具有显著相关性(r=0.905),0.5、1.0 m水层的光照强度下苦草的相对生长率分别为0.14和0.11,而1.5、2.0 m水层的光照强度下苦草出现负增长的情况。水中的溶解氧含量与苦草成活率之间具有显著相关性(r=0.935)。随着水深的增加,溶氧逐渐降低,苦草的成活率也逐渐下降。在2.0 m水层处,溶氧均值为2.76 mg.L-1,苦草的成活率为46.5%,在1.0 m水层处,溶氧为5.66 mg.L-1,苦草成活率为86.5%,因此,淀山湖苦草群落恢复宜先在1.0 m以浅的沿岸带开展。 相似文献
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Xuemei Wang Shuping Situ Weihua Chen Junyu Zheng Alex Guenther Qi Fan Ming Chang 《环境科学学报(英文版)》2016,28(8):72-82
This article compiles the actual knowledge of the biogenic volatile organic compound (BVOC) emissions estimated using model methods in the Pearl River Delta (PRD) region, one of the most developed regions in China. The developed history of BVOC emission models is presented briefly and three typical emission models are introduced and compared. The results from local studies related to BVOC emissions have been summarized. Based on this analysis, it is recommended that local researchers conduct BVOC emission studies systematically, from the assessment of model inputs, to compiling regional emission inventories to quantifying the uncertainties and evaluating the model results. Beyond that, more basic researches should be conducted in the future to close the gaps in knowledge on BVOC emission mechanisms, to develop the emission models and to refine the inventory results. This paper can provide a perspective on these aspects in the broad field of research associated with BVOC emissions in the PRD region. 相似文献
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REMIS is one of key research projects sponsored by the central government. It is recommended to regional EPAs as a main tool of the environmental management. REMIS simulates the functions of the regional EPAs and aimed to improve their management level. The national environmental management information system will base on REMIS.Functional analysis is the kernel of the REMIS system analysis. Data and data flow analysis are used to support the functional analysis.Investigations on the functions of the local EPAs of eight provinces and 12 cities have been taken. The functions were carefully sorted. Modular design method was used in system analysis and system design.The system analysis included functional analysis, data analysis and data flow analysis. The system design is based on the system analysis. HIPO diagram of each modular, data base structure, menu design, selection of hardware and software environment were the main items of the system design. 相似文献
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综述了近30年来国内外关于生物源挥发性有机化合物( BVOCs )排放及其应用的研究进展,包括BVOCs排放的化学组成、影响排放的主要环境因素和排放模式的建立及其应用等。重点探讨BVOCs排放在空气质量模拟应用中的重要性,提出一些值得注意的关键点。最后从BVOCs排放模式机理、基础数据和大气化学输送模式对BVOCs排放处理等方向进行了展望。 相似文献
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QSAR计算中的分子连接性指数法 总被引:4,自引:1,他引:4
本文介绍了分子连接性指数法和原理及各阶指数的计算方法,以及在QSAR计算中的应用实例,并对特殊连接性指数的用法作了分析。 相似文献
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沉水植被构建对上海辰山植物园景观湖水质的影响 总被引:2,自引:0,他引:2
以辰山植物园景观湖为研究对象,研究了景观湖建成初期沉水植物群落构建对水体水质因子的影响;并应用相关性分析(correlation analysis)和主成分分析(principal components analysis)对各水质和生态因子之间的相互关系进行了研究。结果表明,景观湖沉水植被建成1年后,水体水质处于Ⅲ类,其中叶绿素a含量5.48±1.930μg/L、总氮1.40±0.136mg/L、总磷0.080±0.015 mg/L、透明度108±20 cm、高锰酸盐指数5.50±1.26 mg/L;除高锰酸盐指数(CODMn)外,其他水质指标均较构建前有显著改善;并且景观湖水质显著优于外河道补充水源水质。相关性分析表明,景观湖水体叶绿素a含量与N、P营养盐呈显著正相关,但却与水温呈极显著负相关,这显示了草型景观湖水质的显著特征;主成分分析显示,第一主成分包含硝态氮、亚硝态氮、总磷、活性磷、叶绿素、水温、透明度和pH等变量,第二主成分包括高锰酸盐指数和氨氮等变量;第一主成分中的水质参数可作为辰山植物园景观湖后续水生态管理中的主要监测对象;此外,主成分分析还显示TP对水体叶绿素的增加具有很高正权重。 相似文献