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一、概述从财务管理的角度看,跨国公司的显著特征就在于通过各种内部转移机制和方法,使资金和利润在公司内部各部分之间流动。因此,跨国营运资本流量管理的目标可以概括为:在跨国公司总部的统一协调下,使营运资本按照最合适的流量、流向和时机进行运转,为最大限度地提高公司整体效益而创造条件

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Migration of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling

The migration characteristics of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling were investigated experimentally. Four types of carbon nanotubes with the outside diameters from 15 to 80 nm and the lengths from 1.5 to 10 μm were used in the experiments. The refrigerants include R113, R141b and n-pentane. The oil concentration is from 0 to 10 wt.%, the heat flux is from 10 to 100 kW·m-2, and the initial liquid-level height is from 1.3 to 3.4 cm. The experimental results indicate that the migration ratio of carbon nanotube increases with the increase of the outside diameter or the length of carbon nanotube. For the fixed type of carbon nanotube, the migration ratio decreases with the increase of the oil concentration or the heat flux, and increases with the increase of the initial liquid-level height. The migration ratio of carbon nanotube increases with the decrease of dynamic viscosity of refrigerant or the increase of liquid phase density of refrigerant. A model for predicting the migration ratio of carbon nanotubes in the refrigerant-based nanofluid pool boiling is proposed, and the predictions agree with 92% of the experimental data within a deviation of ±20%