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381.
382.
综述了国内外丁二烯过氧化物研究进展,主要包括丁二烯过氧化物的危害性、成因、危险评价和热稳定性,并对今后的研究方向进行了展望。  相似文献   
383.
常用中药中以药用植物占多数,几乎凡具有特殊化学成分及生理作用的植物均可以作为药用植物利用。统计表明,冀南野生药用植物资源丰富,约170种。主要分布在西部山区。本文对其中部分重要药用资源植物的成分、功效作较详细介绍,其它只作一般性介绍:一、冀南重要野生药用植物  相似文献   
384.
重大工业危险源(罐区)监控预警系统   总被引:4,自引:2,他引:2  
系统建立了管理软件和硬件监控相结合的安全生产监控预警系统,在安全管理的基 础上,把罐区诸多的危险参数给予实时监测、报警和控制。本系统实现了生产过程控制与安全监控 相结合,安全监测报警与事故预案相结合,既满足了生产控制又实现了动态的安全管理,对安全生产 具有较大意义。  相似文献   
385.
Mast syndrome is a complicated form of human hereditary spastic paraplegias, caused by a mutation in the gene acid cluster protein 33, which encodes a protein designated as “maspardin.” Maspardin presents similarity to the α/β-hydrolase superfamily, but might lack enzymatic activity and rather be involved in protein–protein interactions. Association with the vesicles of the endosomal network also suggested that maspardin may be involved in the sorting and/or trafficking of molecules in the endosomal pathway, a crucial process for maintenance of neuron health. Despite a high conservation in living organisms, studies of maspardin in other animal species than mammals were lacking. In the cotton armyworm Spodoptera littoralis, an insect pest model, analysis of an expressed sequence tag collection from antenna, the olfactory organ, has allowed identifying a maspardin homolog (SlMasp). We have investigated SlMasp tissue distribution and temporal expression by PCR and in situ hybridization techniques. Noteworthy, we found that maspardin was highly expressed in antennae and associated with the structures specialized in odorant detection. We have, in addition, identified maspardin sequences in numerous “nonmammalian” species and described here their phylogenetic analysis in the context of metazoan diversity. We observed a strong conservation of maspardin in metazoans, with surprisingly two independent losses of this gene in two relatively distant ecdysozoan taxa that include major model organisms, i.e., dipterans and nematodes.  相似文献   
386.
Catalysts of Co1.5Mg1.5/Al0.9Ti0.1O and Co1.5Mg1.5/AlO were successfully prepared by calcinations of corresponding hydrotalcite-like compounds at 800℃ for 4 hr. The derived oxides were of spinel phase and a small quantity of Ti substitution did not change the crystal purity. Their catalytic performance for the NO storage/decomposition was investigated. Ti incorporation enhanced the NO decomposition activity while has an opposite effect on the storage capacity of catalyst. In situ FT-IR spectra of the catalysts showed that the final adsorption species on the catalysts was coordinated nitrates/nitrites. In addition, NO storage/decomposition mechanism has been discussed on the basis of these observations.  相似文献   
387.
聂立伟  崔福义  马华 《环境工程》2012,(Z2):510-514
随着工业的迅猛发展,越来越多的有毒有机污染物被排放到环境中,进而引起一系列环境问题。大量研究表明,生物吸附已经成为去除有毒有机污染物的重要方法,而藻类作为一种理想的生物吸附剂,具有良好的吸附和降解有机污染物的能力。概述了藻类对染料、酚类、多环芳烃三种具有代表性的有毒有机污染物的生物吸附。  相似文献   
388.

The pollination syndrome concept implies that flowers evolved with particular sets of characteristics, such as colors, shapes, orientations, and rewards, as a means of attracting pollinators. However, these traits may have also evolved to deter unwanted visitors. The North American genus Penstemon exhibits a great floral diversity that is mainly associated with bumblebee and hummingbird pollination. Evolutionary shifts from insect pollination to hummingbird pollination have occurred in Penstemon repeatedly, but some species maintain mixed-pollination systems and intermediate floral traits between bee- and hummingbird-pollination modes. The apparently intermediate floral traits of species with mixed-pollination systems might be potentially acting to deter bumblebee foragers. Then, bird-flower traits might be selected with increased hummingbird visitation over evolutionary time might, resulting in specialization to and the evolution of floral traits present in hummingbird-pollinated species. Here, we modified bee-pollination floral traits in Penstemon gentianoides with a mixed pollination system, to resemble hummingbird-pollination traits, and measured the effects of trait modification on bumblebee foraging behavior and plant female reproductive fitness. Our results showed that reduction in the width of the corolla tube and the absence of the corolla lip negatively affects bumblebee visitation and their efficiency as pollinators, and that the synergistic interaction of both traits enhanced the “anti-bee” effect. We conclude that acquisition of floral traits that resemble those of hummingbird-pollination enables Penstemon plant species to deter bumblebee visits.

  相似文献   
389.
With rapid economic growth and urbanization, the Yangtze River Delta(YRD) region in China has experienced serious air pollution challenges. In this study, we analyzed the air pollution characteristics and their relationship with emissions and meteorology in the YRD region during 2014–2016. In recent years, the concentrations of all air pollutants, except O_3,decreased. Spatially, the PM_(2.5), PM_(10), SO_2, and CO concentrations were higher in the northern YRD region, and NO_2 and O_3 were higher in the central YRD region. Based on the number of non-attainment days(i.e., days with air quality index greater than 100), PM_(2.5) was the largest contributor to air pollution in the YRD region, followed by O_3, PM_(10), and NO_2.However, particulate matter pollution has declined gradually, while O_3 pollution worsened.Meteorological conditions mainly influenced day-to-day variations in pollutant concentrations. PM_(2.5) concentration was inversely related to wind speed, while O_3 concentration was positively correlated with temperature and negatively correlated with relative humidity.The air quality improvement in recent years was mainly attributed to emission reductions.During 2014–2016, PM_(2.5), PM_(10), SO_2, NO_x, CO, NH_3, and volatile organic compound(VOC)emissions in the YRD region were reduced by 26.3%, 29.2%, 32.4%, 8.1%, 15.9%, 4.5%, and0.3%, respectively. Regional transport also contributed to the air pollution. During regional haze periods, pollutants from North China and East China aggravated the pollution in the YRD region. Our findings suggest that emission reduction and regional joint prevention and control helped to improve the air quality in the YRD region.  相似文献   
390.
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