目的利用C57BL/6和W/W^v突变小鼠研究Cajal间质细胞(interstitial cells of Cajal,ICC)对小鼠胃肠各部位平滑肌条运动的影响,并通过胆碱能受体拮抗剂阿托品和钠通道阻断剂河豚毒素(tetrodotoxin,TTX)给药干预初步探讨氢溴酸槟榔碱(areco...目的利用C57BL/6和W/W^v突变小鼠研究Cajal间质细胞(interstitial cells of Cajal,ICC)对小鼠胃肠各部位平滑肌条运动的影响,并通过胆碱能受体拮抗剂阿托品和钠通道阻断剂河豚毒素(tetrodotoxin,TTX)给药干预初步探讨氢溴酸槟榔碱(arecoline hydrobromide,Ah)促进小鼠平滑肌条动力作用的机制。方法制备C57BL/6和W/W^v突变小鼠胃肠各部位(胃体、胃窦、空肠和结肠)平滑肌环形肌条标本,分别观察和记录2种小鼠离体胃肠各部位平滑肌条的运动,比较2种小鼠胃肠各部位肌条收缩情况(收缩振幅、收缩频率和张力),并观察Ah对2种小鼠胃肠各部位肌条收缩的影响及阿托品、TTX对Ah促动力作用的干预。结果C57BL/6小鼠胃体部平滑肌环形肌条的收缩为具有较高振幅储存食物和低频率少量推进性的收缩波形,胃窦部为高振幅高张力较高频率推进性的收缩波形,空肠部为低振幅高频率快速推进性的收缩波形,结肠部为分散性中等振幅和频率的收缩波形;W/W^v突变小鼠胃体部环形肌条的收缩频率、收缩振幅都在较低水平,张力较其他部位偏高,胃窦部收缩频率、收缩振幅和张力都在较高水平,空肠部的收缩频率仍是最高,收缩振幅和张力却最低,结肠部的收缩频率最低,收缩振幅和张力处于中等水平;C57BL/6小鼠各部位肌条的收缩力均远大于W/W^v突变小鼠(P<0.05,P<0.01,P<0.001);Ah能明显增加C57BL/6小鼠各部位肌条的收缩力(P<0.05,P<0.01,P<0.001),对W/W^v突变小鼠各部位肌条的收缩力只有轻微增加(P<0.05,P<0.001);阿托品能抑制Ah的促动力作用,而TTX并不能阻断。结论ICCs在调控小鼠胃肠平滑肌条运动中具有重要作用,氢溴酸槟榔碱的促动力作用机制除了ICCs网络的调控外,还有一部分神经调控。另外,氢溴酸槟榔碱可能是经M型受体起作用的。展开更多
综合能源系统(integrated energy system,IES)广泛涉及电/气/氢/热/碳基燃料/可再生能源等异质能源的深度耦合,传统的“能量”视角无法准确评判IES对能源的综合利用水平,亟需新的衡量标准。[火用]作为兼顾能量“量”与“质”双重属性的...综合能源系统(integrated energy system,IES)广泛涉及电/气/氢/热/碳基燃料/可再生能源等异质能源的深度耦合,传统的“能量”视角无法准确评判IES对能源的综合利用水平,亟需新的衡量标准。[火用]作为兼顾能量“量”与“质”双重属性的物理量,近年来正不断融入IES研究领域并从根本上转变人们的用能理念,在未来低碳高效IES的构建上发挥着重要的导向作用。文章首先从[火用]的起源及发展入手,介绍[火用]的概念内涵及向多能系统的融合趋势;然后,从黑箱和白箱两个角度介绍[火用]在IES中的理论模型及分析方法,并评述其特征及适用范围;接着,综述近年来[火用]在IES优化规划与市场经济等领域的融合应用情况,并分析其在IES优化配置、实时调度、生产过程[火用]经济性分析及异质能源定价等关键技术上的导向作用与积极意义。最后,总结全文并对未来发展方向进行展望。展开更多
The passive phase separation concept was proposed to modulate flow patterns for heat transfer enhancement. By the flow pattern modulation, the gas tends to be near the wall and the liquid tends to be in the tube core....The passive phase separation concept was proposed to modulate flow patterns for heat transfer enhancement. By the flow pattern modulation, the gas tends to be near the wall and the liquid tends to be in the tube core. Experiment has been performed to verify the fresh idea and the flow pattern modulation mechanism was analyzed qualitatively. This paper focuses on the numerical simulation of the bubble dynamics for a single bubble in the vertical phase separation condenser tube to quantitatively explore the flow pattern mechanism, based on a multiscale grid system and the volume-of-fluid (VOF) method. It is found that: (1) the modulated liquid film thickness can be decreased by 70% compared to that in the bare tube region; (2) the modulated bubble traveling velocity can be doubled, causing the increased liquid velocity and velocity gradient in the annular region to weaken the fluid boundary layer; (3) the significantly increased bubble traveling velocity in the annular region promotes the mass and momentum exchange between the annular region and the core region, and yields the self-sustained pulsating flow in the core region. The above three factors are benefit for the performance improvement of the heat transfer facilities.展开更多
文摘目的利用C57BL/6和W/W^v突变小鼠研究Cajal间质细胞(interstitial cells of Cajal,ICC)对小鼠胃肠各部位平滑肌条运动的影响,并通过胆碱能受体拮抗剂阿托品和钠通道阻断剂河豚毒素(tetrodotoxin,TTX)给药干预初步探讨氢溴酸槟榔碱(arecoline hydrobromide,Ah)促进小鼠平滑肌条动力作用的机制。方法制备C57BL/6和W/W^v突变小鼠胃肠各部位(胃体、胃窦、空肠和结肠)平滑肌环形肌条标本,分别观察和记录2种小鼠离体胃肠各部位平滑肌条的运动,比较2种小鼠胃肠各部位肌条收缩情况(收缩振幅、收缩频率和张力),并观察Ah对2种小鼠胃肠各部位肌条收缩的影响及阿托品、TTX对Ah促动力作用的干预。结果C57BL/6小鼠胃体部平滑肌环形肌条的收缩为具有较高振幅储存食物和低频率少量推进性的收缩波形,胃窦部为高振幅高张力较高频率推进性的收缩波形,空肠部为低振幅高频率快速推进性的收缩波形,结肠部为分散性中等振幅和频率的收缩波形;W/W^v突变小鼠胃体部环形肌条的收缩频率、收缩振幅都在较低水平,张力较其他部位偏高,胃窦部收缩频率、收缩振幅和张力都在较高水平,空肠部的收缩频率仍是最高,收缩振幅和张力却最低,结肠部的收缩频率最低,收缩振幅和张力处于中等水平;C57BL/6小鼠各部位肌条的收缩力均远大于W/W^v突变小鼠(P<0.05,P<0.01,P<0.001);Ah能明显增加C57BL/6小鼠各部位肌条的收缩力(P<0.05,P<0.01,P<0.001),对W/W^v突变小鼠各部位肌条的收缩力只有轻微增加(P<0.05,P<0.001);阿托品能抑制Ah的促动力作用,而TTX并不能阻断。结论ICCs在调控小鼠胃肠平滑肌条运动中具有重要作用,氢溴酸槟榔碱的促动力作用机制除了ICCs网络的调控外,还有一部分神经调控。另外,氢溴酸槟榔碱可能是经M型受体起作用的。
文摘综合能源系统(integrated energy system,IES)广泛涉及电/气/氢/热/碳基燃料/可再生能源等异质能源的深度耦合,传统的“能量”视角无法准确评判IES对能源的综合利用水平,亟需新的衡量标准。[火用]作为兼顾能量“量”与“质”双重属性的物理量,近年来正不断融入IES研究领域并从根本上转变人们的用能理念,在未来低碳高效IES的构建上发挥着重要的导向作用。文章首先从[火用]的起源及发展入手,介绍[火用]的概念内涵及向多能系统的融合趋势;然后,从黑箱和白箱两个角度介绍[火用]在IES中的理论模型及分析方法,并评述其特征及适用范围;接着,综述近年来[火用]在IES优化规划与市场经济等领域的融合应用情况,并分析其在IES优化配置、实时调度、生产过程[火用]经济性分析及异质能源定价等关键技术上的导向作用与积极意义。最后,总结全文并对未来发展方向进行展望。
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China (51106049)the National Basic Research Program of China (2011CB710703)+3 种基金the Natural Science Foundation of China of International Cooperation Project (51210011)the Beijing Natural Science Foundation (3112022)the Hebei Natural Science Foundation (E2011502057)he Fundamental Research Funds for the Central Universities (12MS44)
文摘The passive phase separation concept was proposed to modulate flow patterns for heat transfer enhancement. By the flow pattern modulation, the gas tends to be near the wall and the liquid tends to be in the tube core. Experiment has been performed to verify the fresh idea and the flow pattern modulation mechanism was analyzed qualitatively. This paper focuses on the numerical simulation of the bubble dynamics for a single bubble in the vertical phase separation condenser tube to quantitatively explore the flow pattern mechanism, based on a multiscale grid system and the volume-of-fluid (VOF) method. It is found that: (1) the modulated liquid film thickness can be decreased by 70% compared to that in the bare tube region; (2) the modulated bubble traveling velocity can be doubled, causing the increased liquid velocity and velocity gradient in the annular region to weaken the fluid boundary layer; (3) the significantly increased bubble traveling velocity in the annular region promotes the mass and momentum exchange between the annular region and the core region, and yields the self-sustained pulsating flow in the core region. The above three factors are benefit for the performance improvement of the heat transfer facilities.
