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91.
SO2和O3动态胁迫烟草致病的暴露试验 总被引:1,自引:0,他引:1
SO_2和O_3动态胁迫烟草致病的暴露试验陈锦云,兰志斌,苏珍山,曾军,王阳青(福建龙岩地区烟科所龙岩364000)关键词S)_2和O_3;烟草;气候斑点病,动态胁迫暴露THEDYNAMICSTRESSEXPOSURETESTONTOBACCOBLADE... 相似文献
92.
近年来随着臭氧损失现象日益严重,到达地球表面的紫外线B辐射不断加强,海洋生态系统受到了前所未有的威胁。UV-B的增强改变了生物体赖以生存的水体环境,影响了浮游植物对营养盐的吸收同化,抑制了浮游植物的光合作用,从而减少了海洋对CO2的吸收能力,其结果直接增加了温室效应。同时UV-B也直接影响生态系统食物链的各个营养级,伤害海洋病毒、细菌和浮游植物,降低浮游动物和仔稚鱼的成活率,进而影响到整个海洋生态系统的结构和功能。 相似文献
93.
94.
介绍了2种不同等离子体发生区和不同测量距离对等离子体发生区沿面蓝光中紫外光的波长和相对光强的影响,所测的臭氧发生量大的等离子体发生区的紫外光的相对光强高,测量距离与相对光强呈指数关系,并且等离子体发生区沿面蓝光具有光催化作用. 相似文献
95.
基于紫外光谱分析的腐殖质混凝控制 总被引:2,自引:2,他引:0
腐殖质是水溶性天然有机物(DOM)的主要成分,对水处理过程有重要影响.为探究利用紫外光谱分析实现饮用水处理在线混凝控制的可行性和理论基础,以含腐殖酸和高岭土配水为实验对象,通过烧杯实验考察了不同水质条件对PACl混凝剂最佳投加量的影响,研究了SUVA_(254)和光谱特征斜率与混凝效果的相关性,利用排阻色谱分析了紫外光谱斜率与水体有机物组分之间的关系.结果表明,混凝剂最佳投加量与DOM浓度呈正比关系,两者计量学关系(以Al/DOC计)为0.61mg·mg~(-1).随混凝剂投加量的增加,腐殖酸溶液的SUVA_(254)从8.9 L·(mg·m)~(-1)下降并稳定至2.0 L·(mg·m)~(-1),有机物去除率与SUVA_(254)值呈正相关.光谱斜率与SUVA_(254)的变化趋势一致,且S_(275~295)与SUVA_(254)线性相关最优(R2=0.81).排阻色谱结果表明,混凝优先去除DOM中的腐殖质组分,S275~295与有机物中腐殖质组分对总UVA_(254)的占比存在明显的线性相关,光谱斜率测定对实现饮用水混凝过程的控制有重要意义. 相似文献
96.
Tropospheric ozone(O_3) is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O_3 damage, several agrochemicals have been assessed,including cytokinin(e.g., kinetin, KIN) and ethylenediurea(EDU) with cytokinin-like activity.In higher plant, leaves are primarily injured by O_3 and protective agrochemicals are often applied by leaf spraying. To our knowledge, the mitigating abilities of EDU and KIN have not been compared directly in a realistic setup. In the present research, impacts of elevated O3(2 × ambient O_3, 24 hr per day, for 8 days) on an O_3 sensitive line(S156) of snap bean(Phaseolus vulgaris), which is often used for biomonitoring O_3 pollution, were studied in a free air controlled exposure system. The day before starting the O_3 exposure, plants were sprayed with a solution of EDU(300 ppm), KIN(1 mmol/L) or distilled water, to compare their protective abilities. The results demonstrated that 2 × ambient O_3 inhibited net photosynthetic rate and stomatal conductance, increased the minimal fluorescence yield of the dark-adapted state, decreased the maximal quantum yield of PSII photochemistry, and led to visible injury. KIN and EDU alleviated the reduction of the photosynthetic performance, and visible injury under O_3 fumigation. The plants sprayed with EDU showed greater ability to mitigate the O_3 damage than those sprayed with KIN. Chlorophyll fluorescence imaging may have detected more precisely the differences in O_3 response across the leaf than the conventional fluorometer. 相似文献
97.
98.
以光化学氧化法处理垃圾渗滤液为研究对象,对不同光反应器、H2O2的投加方式、渗滤液曝气、不同光源以及原水初始COD浓度等影响因素进行了探讨,实验结果表明:旋转式反应器对COD去除效果最高,降膜反应器虽效率略差,但结构简单,光源无污染,易于在工程中使用;H2O2一次性投加更有利于COD的去除;在合适时间段采取曝气方式可提高紫外光氧化反应速度;紫外灯光对COD去除较好,而太阳光对COD去除稍差,可能耗低、成本低,在污染物治理时有广阔的应用前景;COD去除效率随原水初始COD浓度的增加而增加。 相似文献
99.
Decomposition experiments conducted with and without microbial processes are commonly used to study the effects of environmental microorganisms on the degradation of organic pollutants.However,the effects of biological pretreatment (sterilization) on organic matter often have a negative impact on such experiments.Based on the principle of water total organic carbon (TOC) analysis,the effects of physical sterilization treatments on determination of TOC and other water quality parameters were investigated.The results revealed that two conventional physical sterilization treatments,autoclaving and 60 Co γ-radiation sterilization,led to the direct decomposition of some organic pollutants,resulting in remarkable errors in the analysis of TOC in water samples.Furthermore,the extent of the errors varied with the intensity and the duration of sterilization treatments.Accordingly,a novel sterilization method for water samples,0.45 μm micro-filtration coupled with ultraviolet radiation (MCUR),was developed in the present study.The results indicated that the MCUR method was capable of exerting a high bactericidal effect on the water sample while significantly decreasing the negative impact on the analysis of TOC and other water quality parameters.Before and after sterilization treatments,the relative errors of TOC determination could be controlled to lower than 3% for water samples with different categories and concentrations of organic pollutants by using MCUR. 相似文献
100.
A controlled hydroponic experiment was undertaken to investigate Cd uptake in relation to the activity of Cd species in solution other than the free ion (Cd2+) by maintaining a constant Cd2+ activity under variable SO42− and Cl− concentrations exposed to maize (Zea mays var. Cameron) plants. The objectives of these experiments were: (1) to distinguish and quantify the different uptake rates of free and inorganic-complexed Cd from nutrient solution, and (2) to model the uptake of Cd by maize with a Biotic Ligand Model (BLM) in a system which facilitates the close examination of root characteristics. Results of the current experiments suggest that, in addition to the free ion, CdSO40 complexes are important factors in determining Cd uptake in nutrient solution by maize plants. Higher nominal SO42− concentrations in solution generally resulted in a greater Cd accumulation by maize plants than predicted by the Cd2+ activity. A better integration of the complete dataset for the 3 harvest times (6, 9 and 11 days after treatment) was achieved by including consideration of both the duration of Cd exposure and especially the root surface area to express Cd uptake. Similarly, the fit of the BLM was also improved when taking into account exposure time and expressing uptake in terms of root morphological parameters. 相似文献