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101.
从水文地质条件、地貌环境和地球化学环境等3个方面,综述了岩溶环境对多环芳烃(PAHs)迁移转化的影响。针对研究现状及存在的不足,提出了未来可能的研究趋势,包括不同气候条件下发育的岩溶系统的对比研究、不同气候条件和不同岩溶系统快速流和慢速流对PAHs迁移的贡献、碳酸盐岩与PAHs相互作用的机理,以及有机质对PAHs迁移行为的影响。 相似文献
102.
工业搬迁区绿化带土壤铜污染及其在植物体内的迁移 总被引:1,自引:0,他引:1
老工业搬迁区主要道路两旁绿化带土壤由于历经老工业企业的变迁和环境的污染破坏,可在一定程度上对这一地区环境的历史变迁及重金属污染状况起到指示作用。采集沈阳铁西老工业搬迁区绿化带土壤及其绿化乔木和灌木植株样品,分析土壤中铜的总量及生物有效态含量,同时分别分析了绿化乔木(8种)和绿化灌木(6种)植株根、枝条和叶片的含铜量。结果表明,搬迁区绿化带土壤中含铜量为29.14~166.95mg/kg,显著高于沈阳市土壤铜元素的背景值;土壤有效态铜为0.23~1.72mg/kg,达到中等水平(0.3~1.0mg/kg)的占采样点总数的70.0%。数据还显示,绿化乔木和灌木对铜的蓄积能力依品种不同差异显著,同种植物不同部位(根、枝条和叶片)对铜的富集能力不同;总体上,绿化乔木植株体内含铜量的分布规律为根叶片枝条或叶片根枝条,绿化灌木植株体内含铜量的分布规律为根叶片枝条。对铜蓄积能力较强的绿化乔木为榆叶梅(Amygdalus triloba Lindl.)、垂柳(Salix babylonica Linn.)、旱柳(Salix matsudana Koidz.)和银杏(Ginkgo biloba),对铜蓄积能力较强的绿化灌木为大叶女贞(Ligustrum lucidum Ait.)、小叶女贞(Ligustrum quihoui Carr.)和紫叶小檗(Berberis thunbergii cv.Atropurpurea)。 相似文献
103.
基于珠三角大气超级站2013年8月至2014年3月PM2.5、PM2.5中主要水溶性无机离子组分及其重要气态前体物等参数的逐时在线监测结果,揭示当地大气PM2.5中二次无机组分与其气态前体物的相互作用,以及PM2.5理化特性与成因的季节差异。结果表明,观测期间,PM2.5、PM10的年平均质量浓度分别为64.2、105.1μg/m3,PM2.5在PM10中所占比例(PM2.5/PM10)平均为61.1%。SO2-4、NO-3、NH+4的年平均质量浓度分别为16.6、9.0、10.2μg/m3,3者之和(SNA)占PM2.5的比例(SNA/PM2.5)平均为55.8%,体现了二次转化对珠三角地区PM2.5污染的重要影响;不同季节,SNA/PM2.5为46.0%~64.3%,夏季最低,冬季最高,其中SO2-4、NH+4对PM2.5的贡献相对稳定,NO-3贡献的季节差异较大;秋、冬季各项观测参数浓度的日变化规律相对明显,夏季除HNO3和NH3外,多项观测参数在低浓度水平波动,日变化规律不明显;珠三角大气中具有足量气态NH3以中和硫酸盐和硝酸盐,PM2.5中NH+4、SO2-4、NO-3主要以(NH4)2SO4和NH4NO3形式存在;本研究站点夏季的硫氧化率和氮氧化率均高于广州市,这充分体现了该站点的区域性特征。 相似文献
104.
With the environmental carrying capacity reaching its limits and the decreasing margin benefits of traditional production factors, the green transformation and green development through technological innovations has been a major direction for the future development of Chinese industries. However, the characteristics and heterogeneities of various types of industries call for different approaches regarding technological innovations. How to choose the most effective mode of technological innovation according to the characteristics of a certain industry has been a key issue. This paper measures the green total factor productivity of 32 industrial trades using the Slacks Based Measure(SBM)-DDF method. The effects of three innovation modes in the green transformation of industrial industry, including the independent innovation(Ⅱ), the technology introduction(TI), and the government support(GS), are empirically analyzed based on industry heterogeneity. Results indicate that the green total factor productivities of different industries show significant differences if taking into account the energy input and the undesirable output of pollutant emissions. The green total factor productivities of traditional high input,high pollution, and high energy consumption industrial trades were significantly lower than those with obvious green features. The year of 2009 is a leap year for the industrial green transformation in China. For resource-intensive industries, the II and the GS are the important ways to achieve green transformation. For labor-intensive industries, the TI is the best path to achieve green transformation, while for technology-intensive industries, the II is the primary driving force for the promotion of green developments. In addition, the innovation-compensating effect of the current Chinese environmental regulations to the resource-intensive industries has been revealed. Improving the overall scale and the industrial concentration of the industries is also beneficial for the green transformation of the industries. 相似文献
105.
Ruben Buendia Fabio Forcolin Johan Karlsson Bengt Arne Sjöqvist Anna Anund Stefan Candefjord 《Traffic injury prevention》2019,20(3):249-254
Objective: Driver fatigue is considered to be a major contributor to road traffic crashes. Cardiac monitoring and heart rate variability (HRV) analysis is a candidate method for early and accurate detection of driver sleepiness. This study has 2 objectives: to evaluate the (1) suitability of different preprocessing strategies for detecting and removing outlier heartbeats and spectral transformation of HRV signals and their impact of driver sleepiness assessment and (2) relation between common HRV indices and subjective sleepiness reported by a large number of drivers in real driving situations, for the first time.Methods: The study analyzed >3,500 5-min driving epochs from 76 drivers on a public motorway in Sweden. The electrocardiograph (ECG) data were recorded in 3 studies designed to evaluate the physiological differences between awake and sleepy drivers. The drivers reported their perceived level of sleepiness according to the Karolinska Sleepiness Scale (KSS) every 5?min. Two standard methods were used for identifying outlier heartbeats: (1) percentage change (PC), where outliers were defined as interbeat intervals deviating >30% from the mean of the four previous intervals and (2) standard deviation (SD), where outliers were defined as interbeat interval deviating >4 SD from the mean interval duration in the current epoch. Three standard methods were used for spectral transformation, which is needed for deriving HRV indices in the frequency domain: (1) Fourier transform; (2) autoregressive model; and (3) Lomb-Scargle periodogram. Different preprocessing strategies were compared regarding their impact on derivation of common HRV indices and their relation to KSS data distribution, using box plots and statistical tests such as analysis of variance (ANOVA) and Student’s t test.Results: The ability of HRV indices to discriminate between alert and sleepy drivers does not differ significantly depending on which outlier detection and spectral transformation methods are used. As expected, with increasing sleepiness, the heart rate decreased, whereas heart rate variability overall increased. Furthermore, HRV parameters representing the parasympathetic branch of the autonomous nervous system increased. An unexpected finding was that parameters representing the sympathetic branch of the autonomous nervous system also increased with increasing KSS level. We hypothesize that this increment was due to stress induced by trying to avoid an incident, because the drivers were in real driving situations.Conclusions: The association of HRV indices to KSS did not depend on the preprocessing strategy. No preprocessing method showed superiority for HRV association to driver sleepiness. This was also true for combinations of methods for frequency domain HRV indices. The results prove clear relationships between HRV indices and perceived sleepiness. Thus, HRV analysis shows promise for driver sleepiness detection. 相似文献
106.
研究了滤纸对青蒿丛生芽诱导及遗传转化的影响.结果表明,培养基上加铺一层滤纸能够明显促进青蒿丛生芽的诱导,丛生芽诱导率可达到97%.在高效丛生芽诱导体系的基础上,探讨了滤纸在根癌农杆菌介导的青蒿遗传转化中的应用.优化后的青蒿转化体系,抗性丛生芽诱导率可达到59.7%,其中,12.5%的抗性丛生芽能发育成抗性生根植株,生根植株PCR检测均为阳性.在部分PCR检测阳性植株中检测到了GUS的稳定表达.该优化的转化体系对青蒿素生物合成分子调控的研究具有重要意义.图5表1参26 相似文献
107.
108.
生物降解途径的理论预测与QSBR研究 总被引:4,自引:1,他引:4
本文把有机污染生生物降解途径理论预测的结果与QSBR模型中化合物选择相结合,所遵循相同理论生物降解途径作为化合物分组的原则,以分子连接性接数和EHOMO作为结构参数与电性参数,采用逐步回归的方法建立了新的QSBR模型,新模型的预测民实验结果能较好地吻合。 相似文献
109.
王之顺 《城市环境与城市生态》2002,15(2):19-20
文章综述了国内烟气脱硫技术及设备发展的历程和现状,分析了引进国外全套烟气脱硫技术装置对国内用户所造成的巨大经济压力,提出走转化高新技术发展国内烟气脱硫技术的道路,介绍了国内外脱硫技术与国内技术相结合,在天津市重点工程项目上实施的实例。 相似文献
110.