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991.
为了研究泡沫-细水雾与细水雾雾场特性的差异,建立了泡沫-细水雾和细水雾雾场测定系统.利用高速摄像技术、激光器偏光技术、激光粒度分析技术分别对中压工况下的泡沫-细水雾和细水雾雾场参数进行了试验研究.结果表明,雾场形态均保持标准的圆锥状,细水雾和泡沫-细水雾雾场边缘雾化效果较好,雾化效果向中心逐渐变差.系统工作压力对泡沫-细水雾的雾化锥角影响较大,工作压力为1.0 MPa时雾化锥角为51°,工作压力为3.5 MPa时增大到80°.不同压力下细水雾的雾化锥角变化较小,约为80°.泡沫-细水雾锥体中心处的雾流密度与系统工作压力成反比,压力越高,雾场的保护半径越大,雾滴分布越均匀.1.0MPa、1.5 MPa、2.0 MPa、2.5 MPa压力下泡沫-细水雾锥体中心处的雾流密度均大于细水雾锥体中心处的雾流密度.泡沫-细水雾雾滴粒径分布呈现随距喷头垂直距离增大而增大的总体特征,由于泡沫-细水雾雾滴的发泡作用,泡沫-细水雾雾场的雾滴粒径在喷头正下方10~100 cm处均大于细水雾雾场的雾滴粒径. 相似文献
992.
993.
有机物的荧光特性被广泛用来解析其在水体中的来源与分布。荧光光谱技术具有灵敏度高、选择性好、且不破坏样品结构的优点,非常适合用来研究有机物的化学和物理性质。运用三维荧光指纹技术对N市某城市湖泊的有机污染类型和污染程度进行了监测。实验结果表明,三维荧光指纹技术能有效揭示城市湖泊中有机物的动态变化。从七月份到十二月份,N市某城市湖泊的主要有机污染类型为内源污染;其中七月份到九月份还兼有外源污染,而十月份到十二月份基本没有外源污染。实验期间,此城市湖泊水体中C lass III(类蛋白)荧光峰的荧光强度在416.10~298.76之间,C lass I(类腐殖酸)荧光峰的荧光强度在128.90~123.19之间,此城市湖泊的内源污染远大于外源污染。 相似文献
994.
995.
Total pollution effect of urban surface runoff 总被引:3,自引:1,他引:2
LUO Hongbing LUO Lin HUANG Gu LIU Ping LI Jingxian HU Sheng WANG Fuxiang XU Rui HUANG Xiaoxue 《环境科学学报(英文版)》2009,21(9):1186-1193
For pollution research with regard to urban surface runo , most sampling strategies to date have focused on di erences in land usage.
With single land-use sampling, total surface runo pollution e ect cannot be evaluated unless every land usage spot is monitored.
Through a new sampling strategy known as mixed stormwater sampling for a street community at discharge outlet adjacent to river,
this study assessed the total urban surface runo pollution e ect caused by a variety of land uses and the pollutants washed o from the
rain pipe system in the Futian River watershed in Shenzhen City of China. The water quality monitoring indices were COD (chemical
oxygen demand), TSS (total suspend solid), TP (total phosphorus), TN (total nitrogen) and BOD (biochemical oxygen demand). The
sums of total pollution loads discharged into the river for the four indices of COD, TSS, TN, and TP over all seven rainfall events were
very di erent. The mathematical model for simulating total pollution loads was established from discharge outlet mixed stormwater
sampling of total pollution loads on the basis of four parameters: rainfall intensity, total land area, impervious land area, and pervious
land area. In order to treat surface runo pollution, the values of MFF30 (mass first flush ratio) and FF30 (first 30% of runo volume)
can be considered as split-flow control criteria to obtain more e ective and economical design of structural BMPs (best management
practices) facilities. 相似文献
996.
Mingqiang Huang Weijun Zhang Liqing Hao Zhenya Wang Li Fang Ruihong Kong Xiaobin Shan Fuyi Liu Liusi Sheng 《环境科学学报(英文版)》2010,22(10):1570-1575
Smog chamber experiments were performed to investigate the composition of products formed from photooxidation of aromatic
hydrocarbon ethylbenzene. Vacuum ultraviolet photoionization mass spectrometer and aerosol time-of-flight mass spectrometer were
used to measure the products in the gas and particle phases in real-time. Experimental results demonstrated that ethylphenol,
methylglyoxal, phenol, benzaldehyde, and 2-ethylfurane were the predominant photooxidation products in both the gas and particle
phases. However, there were some di erences between detected gas phase products and those of particle phase, for example,
2-ethylfurane, ethylglyoxylic acid, nitroethylbenzene, 3,4-dioxopentanal and ethyl-nitrophenol were only existing in the particle-phase.
The possible reaction mechanisms leading to these products were also discussed and proposed. 相似文献
997.
998.
基于MODIS数据的太湖蓝藻变化与水温关系研究 总被引:3,自引:1,他引:2
以太湖为研究区,基于2008年4~12月的60景EOS—MODIS 1B遥感影像数据。利用NDVI算法结合目视判读解译了水华分布变化的基本信息,通过劈窗算法反演太湖湖面水温,发现在2008年太湖蓝藻生长、暴发、衰退周期中。水华面积的大小与湖面均温值之间关系密切:在20℃以下时表层水温与太湖蓝藻生长暴发或沉寂消亡具有明显的相关性;20℃-30℃时水华的面积大小受到湖面温度和其他因素的共同影响,容易发生大规模蓝藻暴发:30℃以上时过高的表层水温会对蓝藻的上浮聚集具有一定抑制作用:太湖蓝藻全年消亡的临界温度与其初始生长的临界温度相比更低。研究同时发现太湖湖面温度的空间差异是影响蓝藻水华分布迁移的重要因素之一。 相似文献
999.
Seasonal variation of nitrogen and phosphorus in Xiaojiang River—A tributary of the Three Gorges Reservoir 总被引:1,自引:1,他引:0
Zhe Li Jinsong Guo Man Long Fang Fang Jinping Sheng Hong Zhou 《Frontiers of Environmental Science & Engineering in China》2009,3(3):334-340
A yearlong monitoring program in the backwater area of Xiaojiang River (XBA) was launched in order to investigate the eutrophication
of backwater areas in tributaries of the Yangtze River in the Three Gorges Reservoir (TGR) in China, starting after the impoundment
water level of the TGR reached 156 m. From March 2007 to March 2008, the average concentration of total nitrogen (TN) and
total phosphorus (TP) were (1553±484) μg·L−1 and (62±31) μg·L−1, respectively. The mean value of chlorophyll was (9.07±0.91) μg·L−1. The trophic level of XBA was meso-eutrophic, while the general nutrient limitation was phosphorus. The results indicated
that XBA has a strong ability to purify itself and has non-point source pollution from terrestrial runoff. The variation of
TN/TP ratio was caused by a variation in TN rather than in TP when TN/TP < 22. N-fixation from cyanobacteria occurred and
became an important process in overcoming the nitrogen deficit under a low TN/TP ratio. When TN/TP ⩾ 22, the variation of
TP affected the TN/TP ratio more significantly than TN. The increase of TP in XBA was caused mainly by particulate phosphorus,
which could originate from a non-point source as adsorptive inorganic forms after heavy rainfall and surface runoff. An increase
in the river’s flow could also contribute to an unstable environment for the growth of phytoplankton. 相似文献
1000.
Chutian Xu Wei Yue Peirong Sun Shutong Chen Zhengying Wu Nan Xu Li Tang Guangzhou Sheng Dapeng Li 《环境科学学报(英文版)》2022,34(2):170-179
The capping is called passive remediation because the sedimentary P was released and then immobilized by the capping materials. However, the release depends on the environmental conditions. Therefore, a hypothesis was proposed that the oxidant was used to accelerate sedimentary P release and the capping material was used to capture those released P. It is positive remediation to reduce sedimentary P amount. The results show that soluble reactive phosphorus(SRP) concentration in the overlying wat... 相似文献