In order to study the influence of gas-liquid two-phase flow on the performance and internal flow field of a centrifugal pump,the steady three-dimensional flow with different gas volume fractions was simulated by appl...In order to study the influence of gas-liquid two-phase flow on the performance and internal flow field of a centrifugal pump,the steady three-dimensional flow with different gas volume fractions was simulated by applying the Reynolds-average N-S equation and mixture gas-liquid two-phase flow model,and the compressibility of gas was taken into consideration in the simulation. Then the centrifugal pump characteristic and the gas distribution law in different gas volume fractions were analyzed. The computational results show that gas volume fraction has a certain influence on the performance of the centrifugal pump,and the efficiency and head of the pump are on the decline with the increase of it.Static pressure in the impeller increases in the radial direction,but the pressure gradient in the flow direction is different under the different gas volume fractions. The gas volume is distributed mainly in the ipsilateral direction of impeller back shroud in the flow channel of the volute. On the suction side of the blade inlet there is an obvious low-pressure area,which causes bubbles agglutination and higher gas volume fraction. With the gas entering passage flow,gas volume fraction in the suction decreases and the pressure surface rises gradually. Higher gas volume fraction causes air blocking phenomenon in the flow passage and the discharge capacity reduces. The increase of gas volume makes the turbulent motion within the impeller more and more intense,which leads to more and more energy loss.展开更多
缺氧诱导因子-1(HIF-1)是在缺氧细胞中发现的一种转录因子,在生物体氧平衡调节中起关键作用.缺氧诱导因子-1α(HIF-1α)是HIF-1活化的关键调控因子,参与细胞的生长、分化和凋亡的调节.为进一步了解家鹅的缺氧应答系统,本研究参考NCBI上...缺氧诱导因子-1(HIF-1)是在缺氧细胞中发现的一种转录因子,在生物体氧平衡调节中起关键作用.缺氧诱导因子-1α(HIF-1α)是HIF-1活化的关键调控因子,参与细胞的生长、分化和凋亡的调节.为进一步了解家鹅的缺氧应答系统,本研究参考NCBI上公布的鹅HIF-1α基因序列设计引物,并成功克隆了马岗鹅HIF-1αmRNA,获得了HIF-1α完整的ORF序列,全长为2403 bp,编码800个氨基酸.研究表明,马岗鹅HIF-1α基因结构保守,在家禽中的同源性较高且与鸡的同源性最高达到94.1%,蛋白结构主体包含螺旋-环-螺旋模式(Helix loop helix,HLH)、PAS(Per ARNT Sim)蛋白、PAC(Motif C-terminal to PAS motifs)等结构域,符合HIF-1α蛋白的结构特征.组织表达差异分析结果显示HIF-1α基因在肺和胰腺表达高,在肌肉中表达低,在气管中几乎不表达.展开更多
基金The National Natural Science Foundation of China(51679196,51879216,51339005)
文摘In order to study the influence of gas-liquid two-phase flow on the performance and internal flow field of a centrifugal pump,the steady three-dimensional flow with different gas volume fractions was simulated by applying the Reynolds-average N-S equation and mixture gas-liquid two-phase flow model,and the compressibility of gas was taken into consideration in the simulation. Then the centrifugal pump characteristic and the gas distribution law in different gas volume fractions were analyzed. The computational results show that gas volume fraction has a certain influence on the performance of the centrifugal pump,and the efficiency and head of the pump are on the decline with the increase of it.Static pressure in the impeller increases in the radial direction,but the pressure gradient in the flow direction is different under the different gas volume fractions. The gas volume is distributed mainly in the ipsilateral direction of impeller back shroud in the flow channel of the volute. On the suction side of the blade inlet there is an obvious low-pressure area,which causes bubbles agglutination and higher gas volume fraction. With the gas entering passage flow,gas volume fraction in the suction decreases and the pressure surface rises gradually. Higher gas volume fraction causes air blocking phenomenon in the flow passage and the discharge capacity reduces. The increase of gas volume makes the turbulent motion within the impeller more and more intense,which leads to more and more energy loss.
文摘缺氧诱导因子-1(HIF-1)是在缺氧细胞中发现的一种转录因子,在生物体氧平衡调节中起关键作用.缺氧诱导因子-1α(HIF-1α)是HIF-1活化的关键调控因子,参与细胞的生长、分化和凋亡的调节.为进一步了解家鹅的缺氧应答系统,本研究参考NCBI上公布的鹅HIF-1α基因序列设计引物,并成功克隆了马岗鹅HIF-1αmRNA,获得了HIF-1α完整的ORF序列,全长为2403 bp,编码800个氨基酸.研究表明,马岗鹅HIF-1α基因结构保守,在家禽中的同源性较高且与鸡的同源性最高达到94.1%,蛋白结构主体包含螺旋-环-螺旋模式(Helix loop helix,HLH)、PAS(Per ARNT Sim)蛋白、PAC(Motif C-terminal to PAS motifs)等结构域,符合HIF-1α蛋白的结构特征.组织表达差异分析结果显示HIF-1α基因在肺和胰腺表达高,在肌肉中表达低,在气管中几乎不表达.
