The traditional evaporator of water source heat pump system is easy to freeze when the water source temperature is too low in winter.A novel ice source heat pump system is proposed,which can use low temperature surfac...The traditional evaporator of water source heat pump system is easy to freeze when the water source temperature is too low in winter.A novel ice source heat pump system is proposed,which can use low temperature surface water to supply heat to buildings.One of the key problems for safe transportation is velocity range of ice slurry in ice outlet pipeline.In order to study the critical flow velocity of ice slurry in the pipe,an Euler model of horizontal straight pipe and 90°elbow pipe were established by Fluent software.The influence of five factors on the critical flow velocity of two kinds of pipes,including initial ice packing fraction,ice particle size,pipe diameter,length of straight pipe and radius curvature of elbow was studied.It found that the initial ice content should be controlled from 10%to 15%.The inlet flow rate was 20%higher than the critical flow rate under the most unfavorable condition.Ice particle size was less than 0.2 mm.The total length of ice discharge pipeline was less than 50 m.Curvature radius of the bend should be met the minimum requirements of the specification of the pipe used.展开更多
The generation of induced tissue-specific stem cells has been hampered by the lack of well-established methods for the maintenance of pure tissue-specific stem cells like the ones we have for embryonic stem （ES） cel...The generation of induced tissue-specific stem cells has been hampered by the lack of well-established methods for the maintenance of pure tissue-specific stem cells like the ones we have for embryonic stem （ES） cell cultures. Using a cocktail of cytokines and small molecules, we dem- onstrate that primitive neural stem （NS） cells derived from mouse ES cells and rat embryos can be maintained. Furthermore, using the same set of cytokines and small molecules, we show that induced NS （iNS） cells can be generated from rat fibroblasts by forced expression of the transcrip- tional factors Oct4, Sox2 and c-Myc. The generation and long-term maintenance of iNS cells could have wide and momentous implications.展开更多
文摘The traditional evaporator of water source heat pump system is easy to freeze when the water source temperature is too low in winter.A novel ice source heat pump system is proposed,which can use low temperature surface water to supply heat to buildings.One of the key problems for safe transportation is velocity range of ice slurry in ice outlet pipeline.In order to study the critical flow velocity of ice slurry in the pipe,an Euler model of horizontal straight pipe and 90°elbow pipe were established by Fluent software.The influence of five factors on the critical flow velocity of two kinds of pipes,including initial ice packing fraction,ice particle size,pipe diameter,length of straight pipe and radius curvature of elbow was studied.It found that the initial ice content should be controlled from 10%to 15%.The inlet flow rate was 20%higher than the critical flow rate under the most unfavorable condition.Ice particle size was less than 0.2 mm.The total length of ice discharge pipeline was less than 50 m.Curvature radius of the bend should be met the minimum requirements of the specification of the pipe used.
基金supported by USC startup fund to QLY and in part by NIH(Grant No.R01OD010926) to QLY
文摘The generation of induced tissue-specific stem cells has been hampered by the lack of well-established methods for the maintenance of pure tissue-specific stem cells like the ones we have for embryonic stem （ES） cell cultures. Using a cocktail of cytokines and small molecules, we dem- onstrate that primitive neural stem （NS） cells derived from mouse ES cells and rat embryos can be maintained. Furthermore, using the same set of cytokines and small molecules, we show that induced NS （iNS） cells can be generated from rat fibroblasts by forced expression of the transcrip- tional factors Oct4, Sox2 and c-Myc. The generation and long-term maintenance of iNS cells could have wide and momentous implications.
