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21.
贵州乳螱Coptotermes(Polycriniterms)guizhoueusis,新种兵螱(图1—3) 头部深黄稍杂浅淡褐色,上颚赤褐色,上唇、触角和后颏以及胸、腹部和足为深黄色,或略浅于头色。头部仅散布少许长毛,上唇端部具一对长端毛,端毛周围可见数个极微小的毛。乳孔口两侧各具二枚毛,乳孔与触角窝之间各具一枚额侧毛。后颏前缘和 相似文献
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Study on two operating conditions of a full-scale oxidation ditch for optimization of energy consumption and effluent quality by using CFD model 总被引:1,自引:0,他引:1
The operating condition of an oxidation ditch (OD) has significant impact on energy consumption and effluent quality of wastewater treatment plants (WWTPs). An experimentally validated numerical tool, based on computational fluid dynamics (CFD) model, was proposed to optimize the operating condition by considering two important factors: flow field and dissolved oxygen (DO) concentration profiles. The model is capable of predicting flow pattern and oxygen mass transfer characteristics in ODs equipped with surface aerators and submerged impellers. Performance demonstration and comparison of two operating conditions (existing and improved) were carried out in two full-scale Carrousel ODs at the Ping Dingshan WWTP in Henan, China. A moving wall model and a fan model were designed to simulate surface aerators and submerged impellers, respectively. Oxygen mass transfer in the ditch was predicted by using a unit analysis method. In aeration zones, the mass inlets representing the surface aerators were set as one source of DO. In the whole straight channel, the oxygen consumption was modeled by using modified BOD-DO model. The following results were obtained: (1) the CFD model characterized flow pattern and DO concentration profiles in the full-scale OD. The predicted flow field values were within 1.98 ± 4.28% difference from the actual measured values while the predicted DO concentration values were within −4.71 ± 4.15% of the measured ones, (2) a surface aerator should be relocated to around 15 m from the curve bend entrance to reduce energy loss caused by fierce collisions at the wall of the curve bend, and (3) DO concentration gradients in the OD under the improved operating condition were more favorable for occurrence of simultaneous nitrification and denitrification (SND). 相似文献
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一、农业企业化的发展带动城镇化发展,是社会经济发展的基本特征 农业企业向城镇相对集中进行发展:一是有利于提高土地利用效益和生态效益,提高公共设施的利用率,节省投入;二是有利于沟通经济信息避免重复建设,促进生产力的进一步发展。农民逐步进城镇务工经商,生产 相似文献
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Weiling He 《The Journal of Architecture》2013,18(2):161-180
Through discussion of the case of Algiers, this paper exposes the forces by which architecture as a system of meanings and experiences is affected by a broader network of meaning. It examines how the built environment can contribute to the preservation of cultural values, and can also act as a physical instrument of cultural change. The study of the way that the built environment was produced in Algiers under Ottoman rule (fifteenth – nineteenth centuries), and the subsequent transformations that occurred under French colonialism (nineteenth – twentieth centuries), along with the cultural implications of each period, reveals that the extent to which architecture and culture relate to/affect each other depends on the broader political, economic and social context. 相似文献
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在运营维护方面,城市轨道与传统铁路有着密切联系,但因运营特点、线路作业环境不同而又有差异。文章根据地铁维护特点,通过近距离调查轨面光带形态及线路几何尺寸,总结出了光带与线路状态之间的部分关联。 相似文献