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991.
Di Huihui Wang Rui Ren Xiaohong Deng Jianqiang Deng Xiaohua Bu Guijun 《Environmental science and pollution research international》2022,29(6):8191-8204
Environmental Science and Pollution Research - A large amount of fresh tobacco waste with high water content are produced in farmland, and it may cause environmental pollution if it is not properly... 相似文献
992.
以溶剂热法制备Fe_3O_4磁性粒子,通过改良的St?ber法在其上包覆Si O_2,并用3-氨丙基三乙氧基硅烷对表面进行氨基修饰,制得Si O_2-NH_2/Fe_3O_4磁性复合材料,并将其用于制药废水二级出水的吸附处理(吸附剂投加量1 g/L、吸附时间120 min)。表征结果显示:Si O_2-NH_2/Fe_3O_4为粒径(510.0±3.6)nm的球形粒子。实验结果表明:在废水p H为5时,Si O_2-NH_2/Fe_3O_4对TOC、蛋白质、腐殖酸的吸附效果最佳,三者的去除率分别达44.14%,35.58%,33.07%,与Fe_3O_4相比分别提高了25.27,21.76,21.05百分点;废水p H为6时,Si O_2-NH_2/Fe_3O_4对多糖和色度的去除效果最佳,二者的去除率分别达26.03%和62.94%,与Fe_3O_4的最高去除率(p H=5时)相比分别提高了17.84百分点和22.45百分点;Si O_2-NH_2/Fe_3O_4重复使用4次,TOC和色度去除率均达初次使用时的87%以上。 相似文献
993.
城市污水处理厂水样中有机氯农药残留分析 总被引:1,自引:0,他引:1
建立了基于HLB固相萃取柱和气相色谱/电子捕获(GC/ECD)分析城市污水中有机氯农药的分析方法,对北京市五大城市污水处理厂———高碑店、北小河、酒仙桥、清河、方庄污水处理厂进出水水样中有机氯农药进行了分析。在5个污水处理厂的水样中共检出了6种有机氯类农药,分别是α-六六六、β-六六六、γ-六六六、δ-六六六、艾氏剂、4,4’-滴滴伊和异狄氏剂,浓度在0.2~76.4ng/L之间。方法对有机氯农药的回收率达到60.93%~141.50%,方法检测限为(0.27~2.90)ng/L。 相似文献
994.
Shuang Chen Xinrong Ren Jingqiu Mao Zhong Chen William H. Brune Barry Lefer Bernhard Rappenglück James Flynn Jennifer Olson James H. Crawford 《Atmospheric environment (Oxford, England : 1994)》2010,44(33):4116-4125
A comparison of a model using five widely known mechanisms (RACM, CB05, LaRC, SAPRC-99, SAPRC-07, and MCMv3.1) has been conducted based on the TexAQS II Radical and Aerosol Measurement Project (TRAMP-2006) field data in 2006. The concentrations of hydroxyl (OH) and hydroperoxy (HO2) radicals were calculated by a zero-dimensional box model with each mechanism and then compared with the OH and HO2 measurements. The OH and HO2 calculated by the model with different mechanisms show similarities and differences with each other and with the measurements. First, measured OH and HO2 are generally greater than modeled for all mechanisms, with the median modeled-to-measured ratios ranging from about 0.8 (CB05) to about 0.6 (SAPRC-99). These differences indicate that either measurement errors, the effects of unmeasured species or chemistry errors in the model or the mechanisms, with some errors being independent of the mechanism used. Second, the modeled and measured ratios of HO2/OH agree when NO is about 1 ppbv, but the modeled ratio is too high when NO was less and too low when NO is more, as seen in previous studies. Third, mechanism–mechanism HOx differences are sensitive to the environmental conditions – in more polluted conditions, the mechanism–mechanism differences are less. This result suggests that, in polluted conditions, the mechanistic details are less important than in cleaner conditions, probably because of the dominance of reactive nitrogen chemistry under polluted conditions. 相似文献
995.
Liujing Huang Hongfeng Chen Hai Ren Jun Wang Qinfeng Guo 《Environmental monitoring and assessment》2013,185(6):5003-5018
We investigated the effects of major environmental drivers associated with urbanization on species diversity and plant functional traits (PFTs) in the remnant subtropical evergreen broad-leaved forests in Metropolitan Guangzhou (Guangdong, China). Twenty environmental factors including topography, light, and soil properties were used to quantify the effects of urbanization. Vegetation data and soil properties were collected from 30 400-m2 plots at 6 study sites in urban and rural areas. The difference of plant species diversity and PFTs of remnant forests between urban and rural areas were analyzed. To discern the complex relationships, multivariate statistical analyses (e.g., canonical correspondence analysis and regression analysis) were employed. Pioneer species and stress-tolerant species can survive and vigorously establish their population dominance in the urban environment. The native herb diversity was lower in urban forests than in rural forests. Urban forests tend to prefer the species with Mesophanerophyte life form. In contrast, species in rural forests possessed Chamaephyte and Nanophanerophyte life forms and gravity/clonal growth dispersal mode. Soil pH and soil nutrients (K, Na, and TN) were positively related to herb diversity, while soil heavy metal concentrations (Cu) were negatively correlated with herb diversity. The herb plant species diversity declines and the species in the remnant forests usually have stress-tolerant functional traits in response to urbanization. The factors related to urbanization such as soil acidification, nutrient leaching, and heavy metal pollution were important in controlling the plant diversity in the forests along the urban–rural gradients. Urbanization affects the structure and functional traits of remnant subtropical evergreen broad-leaved forests. 相似文献
996.
In the search for a model form of allotment garden in the late 1980s, capable of absorbing surplus farmland while sustaining the capacity of the land to support agriculture, Japanese experts rejected the UK allotment, which was perceived to be of low status and in decline, in favour of the German Kleingarten. This paper suggests that it may be time to reconsider the UK experience, in the light of subsequent moves to rewrite the image and practice of allotment gardening in the UK within the local sustainable development agenda, and the problems which the Japanese version of the Kleingarten model has encountered in the changed economic circumstances of the 1990s. 相似文献
997.
998.
999.
转型时期中国城市化水平变动及动力分析 总被引:33,自引:1,他引:32
收集各省区近20年有关城市化方面的资料,分析了我国在转型时期城市化水平的时空变化规律。分析结果表明我国转型时期城市化水平在时间变化上具有水平起点低,发展速度快的特点;在空间变化上存在着较大的东中西区际和省际差异。在些基础上,利用多元统计方法,定量研究影响我国城市化发展的主动力因子,结果表明:工农业发展推拉因子、产业结构转换因子和出口替代外向因子是影响我国城市化发展的三大主动力因子。但表现在东中西城市化发展的主作用力是不同的。进一步研究表明:东部省区城市化水平与第三产业发展水平、产业结构转换能力和经济外向化密切相关,其中与第三产业发展水平表现最为显著;中部省区城市化水平与大中型工业企业的分面、工农业发展产相关性强;西部省区城市化水平与工业发展水平最为相关。 相似文献
1000.