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831.
通过2013~2017年徐州市环境监测资料分析季风影响下主要大气复合污染物PM2.5和O3的相关性,并基于气象观测资料进一步探究PM2.5和O3相互作用机制的季节变化特征.结果表明:夏季风季节,PM2.5和O3呈正相关,相关系数高达0.56;冬季风季节,PM2.5和O3呈负相关,相关系数为-0.34,均通过了99%的置信检验,表明徐州市PM2.5和O3相互作用呈现相反的季节变化.夏季风季节,太阳辐射强,气温较高,大气氧化性较强,O3主导大气氧化性,大气氧化性通过促进二次颗粒物生成使得PM2.5浓度升高,夏季风季节以O3对PM2.5的促进作用主导城市大气复合污染变化;冬季风季节,太阳辐射弱,气温较低,大气氧化性较弱,高浓度的PM2.5削弱太阳辐射抑制大气光化学,导致O3生成率降低,冬季风季节以PM2.5对O3的抑制作用主导城市大气复合污染变化. 相似文献
832.
833.
Feihu Yao Hailong Liu Guangquan Wang Liming Du Xiaofen Yin Yunlong Fu 《环境科学学报(英文版)》2013,25(6):1245-1251
Paraquat (PQ), a nonselective herbicide, is non-fluorescent in aqueous solutions. Thus, its determination through direct fluorescent methods is not feasible. The supramolecular inclusion interaction of PQ with cucurbit[7]uril was studied by a fluorescent probe titration method. Significant quenching of the fluorescence intensity of the cucurbit[7]uril-coptisine fluorescent probe was observed with the addition of PQ. A new fluorescent probe titration method with high selectivity and sensitivity at the ng/mL level was developed to determine PQ in aqueous solutions with good precision and accuracy based on the significant quenching of the supramolecular complex fluorescence intensity. The proposed method was successfully used in the determination of PQ in lake water, tap water, well water, and ditch water in an agricultural area, with recoveries of 96.73% to 105.77%. The fluorescence quenching values (ΔF) showed a good linear relationship with PQ concentrations from 1.0×10-8 to 1.2× 10-5 mol/L with a detection limit of 3.35×10-9 mol/L. In addition, the interaction models of the supramolecular complexes formed between the host and the guest were established using theoretical calculations. The interaction mechanism between the cucurbit[7]uril and PQ was confirmed by 1H NMR spectroscopy. 相似文献
834.
835.
通过计算地震活动能量距平场,研究了黑龙江及其附近区域3次中等地震前的研究区能量场在地震孕育过程中相关的物理时空变化特征。结果显示,地震活动能量场的时间曲线呈较大幅度上升可能预示了发生中强震的时间段,而地震活动能量场等值线高值变化区对应了可能发生M5以上地震的区域。结合热红外卫星长波辐射(OLR)值发现,地震前能量场等值线高值变化区升温明显,表明研究区能量场处于能量积累(释放)增强的状态。这些特征的提取,对该地区中强地震的中短期预测有一定的指导意义。 相似文献
836.
杜文勇 《防灾科技学院学报》2013,15(3):67-71
GD—L2型流气式固体氡源具有操作简便、体积小、易携带、氡产生率较稳定的性能,与RN—150型负压氡源相比较,它最大的特点就是常压下开放式采样,标定K值的准确度往往受操作熟练程度和气压等气候条件的影响。为减小误差提高K值准确度,标定时采用"双连法"对被标仪器和闪烁室进行采样,根据标定时当地的气压和温度对恒流采样泵流速进行改正,实地验证气压等因素对标定结果的影响,本文还对标定方法和技巧进行定性分析和阐述。 相似文献
837.
洞庭湖地区洪水灾害风险评估 总被引:4,自引:1,他引:3
综合当前国内外学者的理论及方法,以灾害风险系统是致灾因子、孕灾环境和承灾体共同作用的系统为基础,对洞庭湖地区进行洪水灾害风险评估,其中致灾因子用暴雨及以上降雨的加权频次来描述,孕灾环境用地形和河网密度来描述,承灾体脆弱性用内在脆弱性和抗灾救灾能力来描述。首先,对区域洪水致灾因子危险性进行评估;其次,对孕灾环境危险性进行评估;再次,对承灾体脆弱性进行评估;最后,对三者进行叠加分析得出洞庭湖地区洪水灾害风险区划图。其中,沿长江地区、湘江入湖地区和澧水河入湖地区洪水灾害风险高;其次是沿洞庭湖周围地区风险较高;洞庭湖地区边缘风险较低。 相似文献
838.
Xiaoguo Jiao Zhanqi Chen Jun Wu Hongyan Du Fengxiang Liu Jian Chen Daiqin Li 《Behavioral ecology and sociobiology》2011,65(2):325-332
Although the effects of male mating history on female reproductive output and longevity have been studied in insects, few
such studies have been carried out in spiders. In a mating system in which females are monandrous while males are polygynous,
females may incur the risk by mating with successful males that have experienced consecutive matings and suffer from the possible
depletion of sperm and/or associated ejaculates. Here, we examine the effects of male mating history on male courtship and
copulation duration, female reproductive fitness, and female adult longevity of the wolf spider, Pardosa astrigera. Results indicated that male mating frequency had little effect on their subsequent copulation success, and of 35 males tested,
about half of the males were able to copulate with five virgin females successively at an interval of 24 h. Male mating history
had little effect on their courtship duration. However, male mating history significantly affected male copulation duration,
female adult longevity, and reproductive output. Males that mated more frequently copulated longer and more likely failed
to cause their mates to produce a clutch, although there was no significant difference in the number of eggs laid and the
number of eggs hatched regardless of the first clutch or the second one. Multiple mating of male P. astrigera resulted in significant reduction in female adult longevity. Our results indicate that monandrous females mating with multiple-mated
males may incur substantial fitness costs. 相似文献
839.
Gömöryová E Střelcová K Fleischer P Gömöry D 《Environmental monitoring and assessment》2011,174(1-4):31-45
This study focused on the responses of soil microorganisms to different management regimes on disturbed windthrow areas. Microbial parameters potentially serving as indicators of environmental changes within a long-term monitoring of forest development after large-scale disturbance events were assessed. Basal and substrate-induced respiration, N mineralisation, catalase activity, microbial biomass as well as functional diversity based on Biolog assay were determined in soil samples from three disturbed plots and an undisturbed reference plot in the Tatra National Park (Slovakia) since 2006. A relative congruence of inter-annual trends of microbial activity indicators at all plots results from a common response of microbiota to changes of climate at the landscape level after forest stands were destroyed. While catalase activity and functional diversity proved to be useful indicators of temporal trends, microbial biomass seems to reflect different management regimes at the disturbed plots. 相似文献
840.
Chunjie Du Jinsheng Yu Wei Sun Haisheng Han Yuehua Hu Pan Chen Panpan Hou Runqing Liu Li Wang Yue Yang Ruohua Liu Lei Sun 《环境科学学报(英文版)》2019,31(7):4-16
Core-shell magnetic seeds with certain adsorption capacity that were prepared by sulfated roasting, served as the core of a magnetic separation technology for purification of starch wastewater. XRD and SEM results indicate that magnetite's surface transformed to be porous α-Fe_2O_3 structure. Compared with magnetite particles, the specific surface area was significantly improved to be 8.361 from 2.591 m~2/g, with little decrease in specific susceptibility. Zeta potential, FT-IR and XPS experiments indicate that both phosphate and starch adsorbed on the surface of the core-shell magnetic seeds by chemical adsorption, which fits well with the Langmuir adsorption model. The porous surface structure of magnetic seeds significantly contributes to the adsorption of phosphate and starch species, which can be efficiently removed to be 1.51 mg/L(phosphate) and 9.51 mg/L(starch) using magnetic separation. 相似文献