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661.
针对某发电机组循环系统机械通风冷却塔电动风机能耗高的问题,提出将电动风机用水轮机替代,设计了冷却塔电动风机节能改造方案。结果表明:循环水系统水动风机冷却塔改造既能产生合理的社会效益,又能产生良好的经济效益,达到节能减排的目标。 相似文献
662.
三峡水库香溪河库湾氮磷分布状况及沉积物污染评价 总被引:3,自引:0,他引:3
为了解三峡大坝蓄水完成之后香溪河库湾水体及沉积物中氮、磷的分布状况以及沉积物污染水平,2013年4月对三峡水库香溪河库湾进行调查采样,测定表层水及沉积物中氮磷含量和形态组成。结果表明,香溪河库湾表层水总磷(TP)含量范围为0.20~0.51 mg·L~(-1),总氮(TN)含量范围为0.54~2.25 mg·L~(-1),TP主要由磷酸盐(PO_4~(3-))组成,TN主要由硝酸盐(NO_3~-)以及氨氮(NH_4~+)组成,TP在空间上呈现从河口向库尾逐渐升高的分布格局,TN分布从河口向库尾逐渐降低。香溪河库湾沉积物中TP含量变化范围为642~1 189 mg·kg~(-1),TN含量变化范围为867~1 718 mg·kg~(-1),沉积物TP含量分布呈现上游高下游低,沉积物TN分布趋势呈现中间高,两头低。沉积物中TP主要由无机磷(IP)组成,有机磷(OP)所占比例较小,其中IP由钙磷(Ca-P)、铁铝磷(Fe/Al-P)组成,三者含量:Ca-POPFe/Al-P,且沉积物TP含量空间变化受到三者影响(P0.05)。采用单一因子标准指数法对香溪河库湾沉积物中TN、TP污染水平进行评价,结果表明,表层沉积物中TN、TP最低级别污染指数平均值为2.0和1.6,表层沉积物中TN、TP污染指数均超过最低污染水平,且TP的严重级别污染指数达到0.5以上。三峡水库三期蓄水完成以后,香溪河库湾表层水体中氮磷含量较初期蓄水有所升高,各样点沉积物中氮磷含量表现出相同的趋势,沉积物中不稳定磷释放对水体富营养化具有影响,香溪河库湾的表层沉积物已经受到一定的污染,磷污染水平较高。 相似文献
663.
Jiang He Chang-Wei Lü Hong-Xi Xue Ying Liang Saruli Bai Ying Sun Li-Li Shen Na Mi Qing-Yun Fan 《Environmental geochemistry and health》2010,32(1):45-58
This paper analyses the contents and species distributions of rare earth elements (REEs) in the water-suspended particulate-sediment
system of the Baotou section of the Yellow River, China, with known anthropogenic REE input from industrial discharges. The
major forms of REEs were suspended and dissolved in the mainstream and the tributaries of the Baotou section, respectively.
The concentrations of the dissolved and suspended REEs had the same trends in the overlying water along the mainstream, which
increased from the Seqi section (site A) to the mouth of the Sidaosha River (site D), reaching a maximum value at site D,
and tending to decrease thereafter. The contents of REEs in sediment cores showed enrichment with light rare earth elements
(LREEs). The bound to carbonates and to Fe–Mn oxides are the major forms of REE in the secondary phase and the REE exhibited
LREE enrichment pattern and moderate Eu depletion in suspended particulates and surface sediments. The contents and species
distributions of REEs in the water-suspended particulate-sediment system of the Baotou section suggest that the anthropogenic
source of REEs from Baotou city have enhanced REE accumulation to the Baotou section. This information is important for predicting
possible pollution resulting from anthropogenic REE input into rivers. 相似文献
664.
Effect of blue light on early sporophyte development of Saccharina japonica (Phaeophyta) 总被引:1,自引:0,他引:1
Growth and photosynthesis in the blade of Saccharina sporophytes are strongly stimulated by blue light. However, little is known about the effect of blue light on the early development
and longitudinal photosynthesis profile of Saccharina sporophytes. In this study, S. japonica sporelings were cultured under blue or red light for 8 weeks. Blue light affected longitudinal, tangential cell divisions
and tissue differentiation early in sporophyte development. The number of latitudinal cells in the blade under blue light
was over fivefold that under red light. In addition, the number of cell layers was higher in the growing point than in the
blade under blue light, whereas sporelings grown under red light contained only a single cell layer. Under blue light, the
photosynthetic capacities of the growing region, blade and stipe were similar, and the maximum relative electron transport
rate was even lower in the growing point than in the blade. The longitudinal photosynthesis profile suggested that blue light
stimulated the enzymes participating in light-independent carbon fixation in the growing point and accordingly was less dependent
on high light irradiances. Collectively, the results indicated that blue light promotes the early development of S. japonica sporophytes, which was attributed to both photomorphogenetic responses and photosynthetic reactions. 相似文献
665.
Guixiang ZHANG Xitao LIU Ke SUN Ye ZHAO Chunye LIN 《Frontiers of Environmental Science & Engineering》2010,4(4):421-429
Batch sorption experiments were conducted to evaluate the sorption behavior of tetracycline (TC, H3L) on sediments and soils in the presence and absence of cadmium (Cd), as affected by pH and properties of sediments and soils. The results indicated stronger nonlinearity and higher capacity of TC sorption on sediments than on soils. Sorption of TC also strongly depended on environmental factors and sediment/soil properties. Lower pH facilitated TC sorption through a cation exchange mechanism, which also took place at pH values above 5.5, where TC existed as a zwitterion (H2L0) or anions (HL- and L2-). When pH was above 7, however, ligand-promoted dissolution of TC might occur due to TC weakening the Al-O bond of aluminum oxide and the Fe-O bond of iron oxide. Natural organic matter (NOM) plays a more important role in TC sorption than cation exchange capacity (CEC) and clay contents. The presence of Cd (II) increased TC sorption on both sediments and soils, which resulted from the decrease of equilibrium solution pH caused by Cd2+ exchange with H+ ions of sediment/soil surfaces. The increase of TC sorption was also related to the formation of TC-Cd complexes, where Cd2+ acted as a bridge between the sediment/soil and TC. 相似文献
666.
667.
孙英杰 《中国环境管理干部学院学报》2013,(5):75-78
通过研究绿色大学建设过程中出现的不足,提出构建绿色大学评价指标体系是建设绿色大学的前提。以CIS(企业识别系统)理论为依据,从理念层、行为层和物质层三个层面进行研究,构建了一个由3个一级指标12个二级指标和45个三级指标构成的绿色大学评级指标体系。最后对绿色大学的评价方法进行了简单陈述。 相似文献
668.
Strip-mining operations greatly disturb soil, vegetation and landscape elements, causing many ecological and environmental problems. Establishment of vegetation is a critical step in achieving the goal of ecosystem restoration in mining areas. At the Shouyun Iron Ore Mine in suburban Beijing, China, we investigated selective vegetation and soil traits on a tailings dam 7 years after site treatments with three contrasting approaches: (1) soil covering (designated as SC), (2) application of a straw mat, known as “vegetation carpet”, which contains prescribed plant seed mix and water retaining agent (designated as VC), on top of sand piles, and (3) combination of soil covering and application of vegetation carpet (designated as SC+VC). We found that after 7 years of reclamation, the SC+VC site had twice the number of plant species and greater biomass than the SC and VC sites, and that the VC site had a comparable plant abundance with the SC+VC site but much less biodiversity and plant coverage. The VC site did not differ with the SC site in the vegetation traits, albeit low soil fertility. It is suggested that application of vegetation carpet can be an alternative to introduction of topsoil for treatment of tailings dam with fine-structured substrate of ore sands. However, combination of topsoil treatment and application of vegetation carpet greatly increases vegetation coverage and plant biodiversity, and is therefore a much better approach for assisting vegetation establishment on the tailings dam of strip-mining operations. While application of vegetation carpet helps to stabilize the loose surface of fine-structured mine wastes and to introduce seed bank, introduction of fertile soil is necessary for supplying nutrients to plant growth in the efforts of ecosystem restoration of mining areas. 相似文献
669.
孙文华 《安全.健康和环境》2008,8(2):43-44
依据国家防雷技术标准和石油行业标准,结合油田企业拱顶钢油罐的防雷接地装置现状,对拱顶钢油罐的防雷设计与安装进行了探讨. 相似文献
670.
结合心理学知识从人为因素的角度分析和归纳了油气储运设施事故的原因,提出了应对人为因素负面影响的措施和对策。 相似文献