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991.
用氧化-絮凝耦合法处理酸性大红GR废水,以高锰酸钾为氧化剂、聚硅硫酸铁为絮凝剂,脱色率达到94.9%,COD去除率达到55.2%.通过用倒置式生物显微镜观察絮体,对反应机理进行推测.对高锰酸钾与酸性大红之间氧化还原反应产物和氧化-絮凝耦合处理的絮体进行紫外和红外吸收光谱扫描分析,探讨了氧化-絮凝耦合的反应历程和机理:酸性大红被高锰酸钾氧化成小分子有机物而脱色,还原产物新生态水合二氧化锰胶体吸附小分子有机物,并被聚硅硫酸铁卷裹成紧密絮体,氧化与絮凝之间产生协同作用,从而有效去除了色度和COD. 相似文献
992.
考察了镧负载改性TiO2催化剂在太阳光下降解微囊藻毒素LR(MCLR)的效果及其影响因素.结果表明,镧负载改性的TiO2可显著增加MCLR在TiO2表面的吸附量,同时提高MCLR在太阳光下的降解率.随着镧负载量的增加,太阳光下MCLR降解率可从65%提高到95%,pH降低可促进MCLR的降解.改性TiO2对藻毒素的降解存在最佳投加量,实验结果表明,在pH=6,MCLR初始浓度为2 mg/L,0.001-La-TiO2的最佳投量为0.5 g/L,在3 600 μW/cm2太阳光下照射30 min,降解率可达97%. 相似文献
993.
壳聚糖混凝剂除氟的研究 总被引:1,自引:0,他引:1
合成了壳聚糖和丙烯酰胺改性壳聚糖两种高分子混凝剂,并以NaF溶液为研究对象,考察了两种壳聚糖混凝剂投加量、pH值、接触时间及温度对除氟性能的影响.实验结果表明:丙烯酰胺改性壳聚糖的除氟效果优于未改性的壳聚糖;随着两种混凝剂投量的增加,除氟效率增大,当剂量分别大于50 mg/L和60 mg/L时,除氟效率趋于稳定;壳聚糖与改性壳聚糖混凝剂分别在pH值为6.2和5.4时,获得了最佳的除氟效果;接触时间小于12 min时,随着接触时间延长,除氟效率快速增加,大于20 min时,除氟率趋于稳定;混凝温度升高有利于提高除氟率,两种混凝剂在25℃即达到最大除氟率. 相似文献
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对电子装备爆炸振动损伤模式进行了分析,确定了评判准则,并以此为基础对装备损伤的模拟进行研究,建立了爆炸地面振动及结构响应模型、装备结构模型、装备结构响应模型和振动损伤模拟模型. 相似文献
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John E. Fa Jesus Olivero Miguel Á. Farfán Ana L. Márquez Jesús Duarte Janet Nackoney Amy Hall Jef Dupain Sarah Seymour Paul J. Johnson David W. Macdonald Raimundo Real Juan M. Vargas 《Conservation biology》2015,29(3):805-815
We used data on number of carcasses of wildlife species sold in 79 bushmeat markets in a region of Nigeria and Cameroon to assess whether species composition of a market could be explained by anthropogenic pressures and environmental variables around each market. More than 45 mammal species from 9 orders were traded across all markets; mostly ungulates and rodents. For each market, we determined median body mass, species diversity (game diversity), and taxa that were principal contributors to the total number of carcasses for sale (game dominance). Human population density in surrounding areas was significantly and negatively related to the percentage ungulates and primates sold in markets and significantly and positively related to the proportion of rodents. The proportion of carnivores sold was higher in markets with high human population densities. Proportion of small‐bodied mammals (<1 kg) sold in markets increased as human population density increased, but proportion of large‐bodied mammals (>10 kg) decreased as human population density increased. We calculated an index of game depletion (GDI) for each market from the sum of the total number of carcasses traded per annum and species, weighted by the intrinsic rate of natural increase (rmax) of each species, divided by individuals traded in a market. The GDI of a market increased as the proportion of fast‐reproducing species (highest rmax) increased and as the representation of species with lowest rmax (slow‐reproducing) decreased. The best explanatory factor for a market's GDI was anthropogenic pressure—road density, human settlements with >3000 inhabitants, and nonforest vegetation. High and low GDI were significantly differentiated by human density and human settlements with >3000 inhabitants. Our results provided empirical evidence that human activity is correlated with more depleted bushmeat faunas and can be used as a proxy to determine areas in need of conservation action. 相似文献
999.
The gametogenesis and gonad microanatomy of the stalked barnacle Pollicipes cornucopia (Leach) is described. An histological classification of gametogenic development is proposed for the firt time for a species of the Cirripedia. This species has an annual gametogenic cycle on the north-west Spanish coast. Spawning takes place mainly from March to September. Ovaries release gametes at least twice during the gametogenic cycle. 相似文献
1000.
MicrotoxR1 test toxicity values for twenty chlorophenols, twelve chlorobenzenes and thirteen para-substituted phenols have been determined and correlated with the acute and sublethal effects of these chemicals on several species of fish, bacteria and shrimp. The results indicate that the MicrotoxR test provides good estimates of the toxicities to the various biota, as shown by the linear correlation equations presented, and that it is useful for the calculation of structure-activity correlations with physico-chemical parameters, such as the octanol/water partition coefficient. 相似文献