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91.
To be effectively heated in incinerator for MSW is very important for stabilization and completeness combustion, the smaller produce of the PCDD/Fs. At the same time, the transient heat transfer characteristics of the MSW lump decides the stay time of the MSW in incinerator and effects on the operation feature of the combustion equipments. All of these would lead to design the reasonable and clean combustion project, the optimum incinerator and recover energy system. The component, shape, dimension, property, the hardly and inner structure feature of the MSW lump are taken in account, and the effective conduct heat coefficient has been adopted. And then, the physical model is setup with different shape(ball, cylinder, squareness), and the 3-D mathematical model and conduct heat efficient with porous feature for transient heat transfer of MSW lump are presented, at the same time, the simulation tests are gotten in various boundary and the interesting conclusions are gotten: The center stable temperature of the MSW lump is mostly decided by the inner gas temperature of the incinerator and the heated area of the lump. The transient heat transfer characteristics is variously effected by the shape of the MSW lump in incinerator. The transient process becomes longer and the center stable temperature decreases, the volatile can't be easily separated out and the combustion efficiency decreases because of the increasing of the lump feature dimension. 相似文献
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采用热水浸提、醇沉法提取红枣多糖,对红枣多糖提取工艺与一般理化性质进行了研究.选择浸提固液比、温度、时间和浸提次数作为单因素进行梯度实验,确定其条件范围,再通过正交实验L9(33)进一步确定红枣水溶性多糖最佳提取工艺条件.结果表明,最佳提取工艺条件为:固液比1:7,浸提温度80℃,浸提时间2 h,反复浸提2次.理化性质研究结果表明,提取的红枣多糖中含有多肽和AA,为蛋白质复合多糖. 相似文献
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分析了我国北方荒漠化形势和实施农田保护性耕作对防止沙尘暴的作用和意义。根据生态学原理,提 出了加强农田防护林建设和实施留茬、免耕、覆盖等保护性耕作技术措施以及加强农田防沙配套技术体系研究 的一些设想。 相似文献
97.
液体培养研究不同土壤中硝化活性 总被引:2,自引:0,他引:2
A red soil, a fluvo-aquic soil and a permeable paddy soil were used in a long-term investigation to study changes in nitrification with treatments: 1) soil incubation, 2) liquid incubation inoculated with soil samples, and 3) liquid incubation inoculated with ammonia-oxidizing bacteria (AOB) from the soils. There were significant differences (P < 0.001) in nitrification rates among the three soils when measured for 28 days by adding (NH4)2SO4 at the rate of 154 mg N kg-1 dry soil to fresh soil. However, the amounts of nitrifying bacteria in the three soils were not related to soil nitrification capacity. When the soil samples or the isolates of AOB enriched from the corresponding soil were incubated in liquid with pH 5.8, 7.0 and 8.0 buffers and 10 mmol L-1 ammonium nitrogen, there were no significant nitrification differences in the same soil type at each pH. The ability to oxidize ammonia through AOB from different types of soils in a homogeneous culture medium was similar, and the soil nitrification capacity could reflect the inherent properties of a soil. Altering the culture medium pH of individual soil type also showed that acidification of an alkaline fluvo-aquic soil decreased nitrification capacity, whereas alkalinization of the acidic red soil and permeable paddy soil increased their nitrification. For a better insight into factors influencing soil nitrification processes, soil properties including texture and clay composition should be considered. 相似文献
98.
对黄河中游河龙区间晋西北片、陕北片坝库控制面积占比、坝库单位面积库容等参数与水利水土保持措施减沙效益关系进行了研究,结果表明:(1)晋西北片若没有坝库工程,仅靠水土保持坡面治理措施只能取得14%的减沙效益;每增加100km^2的坝库控制面积,即可提高2%的减沙效益;每增加400万m^2的库容,即可提高1%的减沙效益;坝库单位面积库容每提高1万m^2/km^2,减沙效益即可提高约10%。(2)陕北片减沙效益主要由坝库工程产生。减沙效益提高10%,坝库单位面积库容需要提高5万m^2/km^2。要使流域水土保持综合治理减沙效益达到20%以上,坝库单位面积库容应在6万m^2/km^2以上。(3)在黄河中游多沙粗沙区,要实现40%左右的减沙效益,坝库单位面积库容应达到167/m^2/km^2以上。 相似文献
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