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NUMERICAL STUDIES FOR GAS SOLID TWO PHASE STEADY MIXED CONVECTION PROBLEMS WITH PHASE CHANGE
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作者 Chen Yue-nan Yang Xiao-xing Department of Mechanics,Zhejiang University,Hangzhou 310027,P.R China 《Journal of Hydrodynamics》 SCIE EI CSCD 1990年第1期66-73,共8页
A mathematical model for describing gas solid two phase steady mixed convection with phase change has been developed and numerical calculation methods presented.A melting liquid droplet failing a counter gas currenl e... A mathematical model for describing gas solid two phase steady mixed convection with phase change has been developed and numerical calculation methods presented.A melting liquid droplet failing a counter gas currenl expe- riences three processes,cooling of liquid droplet,solidification and cooling of the solid particle.The turbulent model used for Rayleigh number greater than 10~6 is a two equation(k—ε)model of turbulence.For phase change,an improved enthalpy method with varied time step is proposed.The gas particle two phase flow is described by using Eulerian-Lagrangian approach.Modified SIMPLE algorithm and Runge-Kutta method are used in interative calcu- lation.As an example of calculation,the flow in a special 2-dimensional axi-symmetrical prilling tower of diameter 20 m and height 50 m has been performed.Buoyancy effect is important for moving droplet with phase change. The model to be developed and analysis of results obtained in this paper are useful for engineering design in indus- try. 展开更多
关键词 PR NUMERICAL STUDIES FOR gas SOLID TWO phase STEADY MIXED CONVECTION PROBLEMS WITH phase CHANGE gas
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采用流体反应器连续制备可用于T_(1)加权磁共振成像的极小尺寸氧化铁纳米颗粒 被引量:2
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作者 毛宇 李艳 +8 位作者 臧凤超 于昊立 严森 宋青松 秦志国 孙剑飞 陈博 黄晓 顾宁 《Science China Materials》 SCIE EI CAS CSCD 2022年第6期1646-1654,共9页
粒径小于5 nm的极小尺寸氧化铁纳米颗粒(ESIONPs)作为T_(1)加权磁共振成像(T_(1)-MRI)造影剂展现出巨大的发展前景.然而,具有良好生物相容性的ESIONPs的批量生产仍然难以实现.本研究通过特别设计的气/液混合相流体反应器结合共沉淀合成... 粒径小于5 nm的极小尺寸氧化铁纳米颗粒(ESIONPs)作为T_(1)加权磁共振成像(T_(1)-MRI)造影剂展现出巨大的发展前景.然而,具有良好生物相容性的ESIONPs的批量生产仍然难以实现.本研究通过特别设计的气/液混合相流体反应器结合共沉淀合成方法,实现了聚葡萄糖山梨醇羧甲基醚(PSC)包覆的ESIONPs的连续制备,且其粒径在1.8–4.0 nm范围内可控.在不同粒径的ESIONPs中,粒径为3.7 nm的ESIONPs具有最好的T_(1)-MRI造影效果,特别是在临床3 T磁共振扫描设备下具有高的r_(1)值(4.11(mmol L^(−1))^(−1)s^(−1))和低的r_(2)/r_(1)值(7.90),并且在水相、细胞和血管环境中均展现出良好的T_(1)-MRI对比效果.此外,PSC包覆的ESIONPs具有良好的生物安全性,在水相中具有良好的分散性和长期稳定性,有望成为临床可用的安全有效的T_(1)-MRI造影剂. 展开更多
关键词 ESIONPs T1-contrast agents MRI coprecipitation method gas/liquid mixed phase fluidic reactor
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