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651.
电机硅钢片冲孔模具在制造及使用中常因各种原因使某个槽孔损坏而需要修补.此文介绍了该类模具的修补技术.实践证明:该技术可延长硅钢片冲孔模具的使用寿命.  相似文献   
652.
改性活性炭在环境保护中的应用   总被引:14,自引:6,他引:14  
活性炭是一种应用广泛的吸附催化剂 ,其性能取决于它的孔隙结构和表面化学性质。为了提高其吸附效率和改善其吸附选择性及其催化性能 ,往往需要对活性炭的孔隙结构进行调整以及改变其表面化学性质。综述了活性炭的改性方法及其特点、改性活性炭在环境保护中的应用及其再生等方面的研究概况  相似文献   
653.
AS法制浆废液改性减水剂实验研究   总被引:1,自引:0,他引:1  
通过实验,对AS法麦草、芦苇造纸制浆废液加入Ba(OH)2溶液和吐温-80进行化学改性,制成木素磺酸盐为主要成份的混凝土减水剂,制得的减水剂的3项主要性能指标均达到以国家标准,它们在掺量3‰时净浆减水率为6%-8%,砂浆减水率为15%-16%,掺麦草、芦苇浆废液减水剂的砂浆3d抗压强度分别提高28%和30%,7d抗压强度分别提高18.6和26.4%。  相似文献   
654.
肖瑜  杨国清  张淑华 《环境工程》2003,21(2):46-47,51
通过对废旧聚丙烯塑料进行填充改性试验 ,研究了重质碳酸钙、超细重钙、滑石粉对废旧聚丙烯塑料进行改性后的塑料试样的抗拉强度、抗弯强度、断裂伸长率以及扫描电镜图像的影响 ,为填料的选用提供试验依据  相似文献   
655.
改性碳纳米管对Fe~(3+)的吸附研究   总被引:1,自引:1,他引:1  
采用硝酸浸泡氧化方法改性碳纳米管,用于吸附水溶液中Fe3+的实验研究,用分光光度法进行测定。结果表明,改性碳纳米管吸附去除Fe3+效能较未改性的碳纳米管有显著的提高。通过对吸附数据的拟和,发现在所研究的温度范围内吸附等温线符合弗仑德利希(Freundlich)吸附等温式。  相似文献   
656.
The Response of Avian Feeding Guilds to Tropical Forest Disturbance   总被引:1,自引:0,他引:1  
Abstract:  Anthropogenic habitat disturbance is a major threat to tropical forests and understanding the ecological consequences of this disturbance is crucial for the conservation of biodiversity. There have been many attempts to determine the ecological traits associated with bird species' vulnerability to disturbance, but no attempt has been made to synthesize these studies to show consensus. We analyzed data from 57 published studies (covering 1214 bird species) that investigated the response of tropical bird assemblages to moderate forest disturbance (e.g., selective logging). Our results show that the mean abundance of species from six commonly reported feeding guilds responded differently to disturbance and that species' ecological traits (body size, local population size, and geographic range size) and evolutionary relationships may influence responses in some guilds. Granivore abundance increased significantly and insectivore and frugivore abundance decreased significantly following disturbance. These general conclusions were robust to the effects of ecological traits and phylogeny. Responses of carnivores, nectarivores, and omnivores were less clear, but analyses that accounted for phylogeny indicated that these guilds declined following disturbance. In contrast to the other guilds, the reported responses of carnivores and nectarivores differed among regions (Asia vs. Neotropics) and were influenced by the sampling protocols used in different studies (e.g., time since disturbance), which may explain the difficulty in detecting general responses to disturbance in these guilds. Overall, general patterns governed the responses of species to habitat disturbance, and the differential responses of guilds suggested that disturbance affects trophic organization and thus ecosystem functioning.  相似文献   
657.
Summary. Breeding burrows of Parastizopus armaticeps armaticeps, a fossorial desert tenebrionid beetle, are cleptoparasitised by the closely related Eremostibes opacus. Gas chromatographic analyses show a high congruity of the cuticular hydrocarbons of both species. We compare these hydrocarbon patterns with those of four other Stizopina species and the Scaurini Herpiscius sommeri. In a bioassay, dummies treated with cuticular hydrocarbon extracts of E. opacus and the P. a. bifidus parasite E. bushmanicus were mostly ignored by P. a. armaticeps, whereas dummies with applied extracts of the remaining species were heavily attacked. We show that there is a correlation between agonistic behaviour of P. a. armaticeps towards the intruder and the chemical similarity of the cuticular hydrocarbons of the two species. Furthermore, we produced quantitatively modified hydrocarbon patterns of E. barbatus by changing the temperature at which this species was kept. The new 30 °C type was chemically similar to E. opacus, and was frequently ignored by P. a. armaticeps, whereas a reduction of the temperature to 20 °C only had minor effects on the hydrocarbon pattern. Furthermore, we show that the addition of one single component, heptacosane, to the cuticular hydrocarbon extract of E. opacus alters the host’s reaction. We discuss the role of cuticular hydrocarbons for the recognition of this host-parasite system and the relevance of quantitative characters in the hydrocarbon pattern for the discrimination of the host.  相似文献   
658.
从岩豆(Millettia dielsiana Harms ex Diels)种妇中分离纯化得到的岩豆凝集素(简称MDL)经链霉蛋白酶水解,测得其分子中含有4个色氨酸(Trp)残基。用N-溴代丁二酰亚胺(NBS)对MDL分子中的色氨酸残基进行化学修饰,在无变性剂存在下有3.6个Trp残基被修饰,在变性条件下可修饰3.8个Trp残基。修饰后MDL活性均丧失,且甘露糖对MDL活性雎有保护作用。表明Tr  相似文献   
659.
聚丙烯酰胺是一种使用范围广、处理效果好的高分子絮凝剂,具有良好的水溶性、优良的絮凝性能和吸附性能.文章总结了聚丙烯酰胺阴离子化、阳离子化、单体共聚的常见改性方法.列举了其改性产物在废水处理中的应用和取得的良好效果.对聚丙烯酰胺改性研究的必要性和有效性进行了说明.表明:聚丙烯酰胺经过改性后可提高使用效果、拓宽使用范围、减少投药量等优点.最后对聚丙烯酰胺改性的发展方向做了展望,改善现有絮凝剂性能和发展高品质絮凝剂是将来研究的重点.  相似文献   
660.
ABSTRACT: The objective of this paper is to examine a deficit in water for the Hsinchu area, the location of Taiwan's “Silicon Valley.” The methods suggested in this paper to diagnose water shortage problems are simple and practical. The results show that Hsinchu is in an area without sufficient water to meet demand for domestic and industrial uses. Until the completion of the Baoshan II Reservoir in 2006, the most feasible options for the Taiwan Water Supply Corporation to offset the water deficiency in Hsinchu City over the next five years are: (a) to obtain water gratuitously from the southern Yungheshan Reservoir; (b) to import additional water at an extra charge from other sources such as the northern Shihmen Reservoir and the agricultural sector; and (c) to conduct a comprehensive water conservation program at the Hsinchu Science‐based Industrial Park.  相似文献   
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