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排序方式: 共有2554条查询结果,搜索用时 9 毫秒
521.
雾化电晕净化烹调油烟技术   总被引:1,自引:0,他引:1  
对雾化电晕放电极雾化过程、荷电液滴的捕集原理、自清洗作用进行探讨,在相同电压下雾化负电晕放电电流高于干式负电晕放电电流,极间大量荷电液滴具有很高的荷质比,并高速向极板驱进,对烟尘具有静电凝并和动力凝并除尘作用,具有高效净化油烟、自清洗极板的功能,此项净化烹调油烟的新技术,优于传统油烟净化技术,具有很好的应用价值和前景。  相似文献   
522.
以石油酸为主要原料的重油乳化剂的研制   总被引:1,自引:0,他引:1  
采用石油酸与三乙醇胺,非离子型表面活性剂复配制备了一种廉价的重油乳化剂,最佳配方为石油酸500mg,三乙醇胺25mg,非离子表面活性剂2为25mg,乳化助剂H20mg,pH11(共占乳化油总质量的0.57%),可使油水质量比为70:30的油包水型乳化重油在80℃下稳定36h,实验过程中采用均匀设计与调优软件进行实验方案的设计和实验结果的优化,考察了乳化剂中石油酸与三乙醇胺和非离子表面活性剂量的协同作用以及PH的影响。结果表明,组分间交互作用明显,在不同的配方下,组分的作用会有很大变化,有时甚至会是相反的。  相似文献   
523.
The leakage of fluid leaving a puncture in a pressurized vessel immersed in a quiescent, miscible medium is studied under steady flow conditions. This problem has engineering applications in submerged pipelines and hazardous gas lines. The leakage rate for the puncture is characterized as functions of various hydrodynamic and geometric conditions. Dimensional analysis shows that the leakage percent, Q*, is a function of the Reynolds number, the pressure ratio between the center of the tube and the external hydrostatic pressure, P*, and the hole-to-main tube diameter ratio, D*. The effect of puncture shape is also examined, rectangular and circular. A 3-D finite volume computational model is constructed for laminar flow of a Newtonian fluid under steady conditions and validated with supporting experiments. The results show that the fractional leakage rate Q* increases with P* and approaches a constant value at high P* for a fixed Reynolds number. In addition, it is found that the leakage rate increases with decreasing Reynolds number at a fixed pressure ratio. The geometric effect of the diameter ratio is shown to have a more pronounced effect near a pressure ratio of two with more fluid exiting the puncture for larger diameter ratios. The results of the shape analysis show that the circular puncture has the largest fractional leakage when compared to a rectangle with an equivalent cross-sectional area.  相似文献   
524.
Oil spill contingency plans are available for most coastlines but the amount of useful environmental data is variable. The information should be held on a GIS base. High risk areas should be identified and the pre-existing store of environmental knowledge should be commensurately extensive and should be available in considerable spatial detail. Contingency plans still depend on basic lists of coastal types as defined by static, sediment based shoreline characteristics. There is a lack of dynamic, process information. TheBraer oil spill of 1993 provides a case study of the application of sound coastal geomorphological and ecological data to impact assessment. Monitoring of the ecological effects of this massive oil spill reinforces other research which indicates that most coastlines can recover naturally from oil spills, and that oil spill clean up techniques may not necessarily benefit rapid shoreline recovery. Although pre-existing environmental informations is important, the key decisions must be taken quickly and are frequently judgmental and, therefore, place a premium on gathering appropriate scientific expertise to the site of the spill as soon as possible and with sufficient powers to affect both the oil spill response, to initiate early surveys of damage and to facilitate the initial monitoring programme.  相似文献   
525.
应用假单胞菌进行防蜡作用的研究   总被引:1,自引:0,他引:1  
假单胞菌L-11菌体与其胞外产物可以作为一种很好的防蜡剂,对L-11的发酵条件进行了优化,确定了最适发酵培养基的配方,发酵培养基以葡萄糖、蛋白胨为其最适碳、氮源,防蜡剂生产的发酵条件为:前16h的发酵温度为35℃,后期将温度降至20℃,发酵液的pH=4.5为发酵终点,此时发酵液在内条件下的防蜡率为78%,将上述所得菌液在大庆油田做了防蜡实验,结果表明,注入L-11的油井洗井周期有所延长,实验证明了L-11的发酵液可以作为一种经济、有效的蜡剂。  相似文献   
526.
Summary. Many species of insects sabotage the pressurized defense vessels of their host plants prior to feeding. This behavior, however, does not render leaves indefinitely suitable, as some species employing this behavior eventually abandon uneaten portions of sabotaged leaves. In this study, we examined whether and to what degree wild parsnip, Pastinaca sativa, is capable of restoring its pressurized defenses and whether cabbage loopers, Trichoplusa ni, which normally trench parsnip leaflets, benefit from their trenching behavior. The pressurized oil tubes of parsnip leaves are rich in toxic terpenoids and furanocoumarins. A disruption of the integrity of the tubes (via razor blade nicks) in leaflets revealed that that some of their contents were expelled at the break and that some movement of oil from outside the leaflet (i.e., the midvein) occurred, bolstering furanocoumarin levels in the leaflet within minutes. Pressure and chemical content in a leaflet’s oil tubes were also shown to be restored within 24 hours of depressurization. This recovery ability allowed parsnip leaflets to respond to daily depressurizations by mechanical damage for up to at least 5 assaults, cumulatively causing an approximate ten-fold increase in furanocoumarins. Cabbage loopers fed parsnip leaflets that were artificially trenched accumulated twice as much body mass as larvae fed leaflets augmented with furanocoumarins equivalent to the quantity that would be avoided through trenching, indicating that trenching does benefit the herbivore. Although parsnip recovers from trenching rapidly, it does not do so within the time that cabbage loopers consume trenched leaflets  相似文献   
527.
泥炭净化含油污水的技术和方法   总被引:3,自引:0,他引:3  
泥炭比重小,重量轻,富含有机质,是一种吸附能力很强的吸油。本文通过大量试验论述了泥炭净化含油污水的实验条件和方法。结果表明,泥炭经热加工处理后,由原来的亲水性变成疏水性,在含油污水中实现吸油而不吸水;采用不同的净化方式效果不同,静态方式泥炭可吸附其自身重量的5-10倍的油,动态吸油高达10倍以上。藓类泥炭,草本泥炭及木本泥炭对油的吸附效果不同,分别可吸附油6L/kg-9.5L/kg,4L/kg-8  相似文献   
528.
Impacts of Roads and Hunting on Central African Rainforest Mammals   总被引:7,自引:0,他引:7  
Abstract:  Road expansion and associated increases in hunting pressure are a rapidly growing threat to African tropical wildlife. In the rainforests of southern Gabon, we compared abundances of larger (>1 kg) mammal species at varying distances from forest roads and between hunted and unhunted treatments (comparing a 130-km2 oil concession that was almost entirely protected from hunting with nearby areas outside the concession that had moderate hunting pressure). At each of 12 study sites that were evenly divided between hunted and unhunted areas, we established standardized 1-km transects at five distances (50, 300, 600, 900, and 1200 m) from an unpaved road, and then repeatedly surveyed mammals during the 2004 dry and wet seasons. Hunting had the greatest impact on duikers ( Cephalophus spp. ), forest buffalo ( Syncerus caffer nanus ), and red river hogs ( Potamochoerus porcus ), which declined in abundance outside the oil concession, and lesser effects on lowland gorillas ( Gorilla gorilla gorilla ) and carnivores. Roads depressed abundances of duikers, sitatungas ( Tragelaphus spekei gratus ), and forest elephants ( Loxondonta africana cyclotis ), with avoidance of roads being stronger outside than inside the concession. Five monkey species showed little response to roads or hunting, whereas some rodents and pangolins increased in abundance outside the concession, possibly in response to greater forest disturbance. Our findings suggest that even moderate hunting pressure can markedly alter the structure of mammal communities in central Africa. Roads had the greatest impacts on large and small ungulates, with the magnitude of road avoidance increasing with local hunting pressure.  相似文献   
529.
稠油污水处理高效反相破乳剂应用现状   总被引:1,自引:0,他引:1  
总结了稠油污水的特点及造成稠油污水难处理的原因,介绍了反相破乳剂的作用机理,提出了作为反相破乳剂的要求,评述了国内稠油污水处理的反相破乳剂的应用现状,分析了稠油污水处理用反相破乳剂的发展方向。  相似文献   
530.
文章对如何提高低浓度样品测量的准确度进行了探讨.在测量低浓度的水样时,在萃取过程中除了四氯化碳会对水样中的油份进行萃取,水对四氯化碳中的极性物质也进行反萃取,当样品中含油浓度很低时,由于四氯化碳含极性物质可能大于油分含量,从而出现负值.因此测定低浓度水样中的石油类和动植物油是一项精细的工作,在实际工作中应该尽量采取下文所述的方法避免这种情况,只有做好了测量的各个环节,才能保证测量结果的精确可靠.  相似文献   
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