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纳米TiO_2光催化空气净化技术研究进展 总被引:3,自引:0,他引:3
本文对纳米TiO2光催化净化空气中挥发性有机化合物(VOCs)的技术原理、国内外研究现状和进展进行概述,简介部分使用光催化空气净化技术的商业产品,展望该技术的应用前景。 相似文献
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Andrea Riedel Christine Michel Michel Gosselin Bernard LeBlanc 《Journal of Marine Systems》2008,74(3-4):918
An understanding of microbial interactions in first-year sea ice on Arctic shelves is essential for identifying potential responses of the Arctic Ocean carbon cycle to changing sea-ice conditions. This study assessed dissolved and particulate organic carbon (DOC, POC), exopolymeric substances (EPS), chlorophyll a, bacteria and protists, in a seasonal (24 February to 20 June 2004) investigation of first-year sea ice and associated surface waters on the Mackenzie Shelf. The dynamics of and relationships between different sea-ice carbon pools were investigated for the periods prior to, during and following the sea-ice-algal bloom, under high and low snow cover. A predominantly heterotrophic sea-ice community was observed prior to the ice-algal bloom under high snow cover only. However, the heterotrophic community persisted throughout the study with bacteria accounting for, on average, 44% of the non-diatom particulate carbon biomass overall the study period. There was an extensive accumulation of sea-ice organic carbon following the onset of the ice-algal bloom, with diatoms driving seasonal and spatial trends in particulate sea-ice biomass. DOC and EPS were also significant sea-ice carbon contributors such that sea-ice DOC concentrations were higher than, or equivalent to, sea-ice-algal carbon concentrations prior to and following the algal bloom, respectively. Sea-ice-algal carbon, DOC and EPS-carbon concentrations were significantly interrelated under high and low snow cover during the algal bloom (r values ≥ 0.74, p < 0.01). These relationships suggest that algae are primarily responsible for the large pools of DOC and EPS-carbon and that similar stressors and/or processes could be involved in regulating their release. This study demonstrates that DOC can play a major role in organic carbon cycling on Arctic shelves. 相似文献
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天然高分子改性阳离子絮凝剂的絮凝性能和应用研究 总被引:6,自引:0,他引:6
介绍了以玉米芯为原料,以阳离子醚化剂为改性剂,合成阳离子型改性高分子絮凝剂(DSL)的方法,并对该絮凝剂的性能和应用进行了研究。结果表明,用玉米芯粉改性而成的高分子阳离子型絮凝剂絮凝性能优于六水氯化铝和国产的聚丙烯酰胺,具有产生絮体大,沉降速度快等特点,将其用于天然地下水、城市生活污水、工业污水的处理,获得了良好的絮凝效果。 相似文献
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本文建立了密闭舱室挥发性有机化合物(VOCs)被动式采集与非靶向测试方法。采用极性和非极性填料进行被动式采样,分析结果可互相对比且互为补充,采样方式简单、便携、稳定。运用目前先进的气相色谱-高分辨质谱(GC-HRMS)分析方法可高灵敏度、高分辨率鉴别采样中的VOCs组分,8个舱室采样位点共筛查出70种低浓度VOCs污染物。在得到的各类VOCs含量数据中,以多环芳烃(PAHs)这一类致癌性和致突变性污染物为例,根据含量热图分析获取多环芳烃在舱室中的分布规律,并推测其主要来源于机舱和设备舱中油料挥发以及厨房烹饪油烟。该方法的建立将更加高效、准确筛查舱室VOCs组分并进行污染源解析,有助于舱室大气环境质量提升和舰艇战斗力生成。 相似文献
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Vertical profiles of particulate organic matter and its relationship with chlorophyll-a in the upper layer of the NE Mediterranean Sea 总被引:1,自引:0,他引:1
Particulate organic matter (POM), nutrients, chlorophyll-a (CHL) and primary production measurements were performed in the upper layer of three different regions (cyclonic, anticyclonic and frontal+peripherial) of the NE Mediterranean Sea in 1991–1994. Depth profiles of bulk POM exhibited a subsurface maximum, coinciding with the deep chlorophyll maximum (DCM) established near the base of the euphotic zone of the Rhodes cyclone and its periphery, where the nutricline was situated just below the euphotic zone for most of the year. Moreover, the POM peaks were broader and situated at shallower depths in late winter–early spring as compared to its position in the summer–autumn period. Under prolonged winter conditions, as experienced in March 1992, the characteristic POM feature disappeared in the center of the Rhodes cyclone, where the upper layer was entirely occupied by nutrient-rich Levantine deep water. Deep convective processes in the cyclonic gyre led to the formation of vertically uniform POM profiles with low concentrations of particulate organic carbon (POC) (2.1 μM), nitrogen (0.21 μM), total particulate phosphorus (PP) (0.02 μM) and chlorophyll-a (0.5 μg/L) in the euphotic zone. Though the Levantine deep waters ascended up to the surface layer with the nitrate/phosphate molar ratios (28–29) in March 1992, the N/P molar ratio of bulk POM in the upper layer was low as 10–12, indicating luxury consumption of phosphate during algal production. Depth-integrated primary production in the euphotic zone ranged from 38.5 for oligotrophic autumn to 457 mg C m−2 day−1 for moderately mesotrophic cool winter conditions. 相似文献
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Carbon cycling in the Weddell Sea was investigated during the ANT X/7 cruise with `FS Polarstern' December 1992–January 1993. Samples were taken on a cross section from Kapp Norvegia to Joinville Island, and on a section from the Larsen Ice Shelf to the northeast. The following quantities were measured: total carbon dioxide (TCO2), fluorescence from humic substances and total organic carbon. The distribution of TCO2 was strongly positively correlated to the time elapsed since the various water masses were last ventilated. In general, humic substance fluorescence was positively correlated with TCO2, with the exception of the productive part of the western Weddell Sea, where the correlation was negative in the surface mixed layer. The increased fluorescence at the surface is suggested to be a result of biological production. The distribution of total organic carbon showed less structure, since this quantity includes a particulate component, which is subject to dispersion processes different from those of the dissolved components TCO2 and humic substances. The mean total organic carbon concentration below the surface mixed layer was 50 μmol l−1. At some stations, a steep TOC maximum around 2000 m depth was observed. This was interpreted to result from mass sinking of phytoplankton blooms. Total organic carbon had a maximum in surface water, and at some stations also a second subsurface maximum. In the Warm Deep Water (WDW), TCO2 and fluorescence had their maximum values, while total organic carbon tended to be low. In low productivity surface water in the eastern part of the Kapp Norvegia–Joinville Island section, the lowest flourescence was found. Surface water is eventually formed from Warm Deep Water, which had the highest fluorescence values, and therefore it is concluded that humic substances were removed in situ from surface water. In the central area of the Weddell Sea, TCO2 and fluorescence showed the highest Warm Deep Water maxima, while total organic carbon was low. The Warm Deep Water in this area is part of the so-called Central Intermediate Water which circulates for a long time within the Weddell Gyre. Reduced total organic carbon, which coincides with the most pronounced Central Intermediate Water characteristics, and high TCO2 can thus both be accounted for by continued degradation of organic matter in this water mass. The associated fluorescence maximum implies that humic substances are also produced during mineralisation. Recently formed bottom water, by contrast, could be seen as patches of low TCO2, low fluorescence and high total organic carbon along the western slope of the Weddell Sea. 相似文献