SCRamjet is exposed to severe thermal environments during hypersonic flights,which poses a serious challenge to the engine cooling technology.Regenerative cooling with hydrocarbon fuel is considered promising,in which...SCRamjet is exposed to severe thermal environments during hypersonic flights,which poses a serious challenge to the engine cooling technology.Regenerative cooling with hydrocarbon fuel is considered promising,in which the hydrocarbon fuel flows through micro channels(200μm-3 mm)to absorb the combustion heat release.With strictly limited hydrocarbon fuel onboard,heat transfer deterioration and over-temperature are highly possible.In this paper,micro ribs with staggered side gaps are introduced and numerically studied to enhance the heat transfer.Compared with the straight channel and channel with straight micro ribs,the staggered side gaps alleviate the local low velocity zone and intensify the longitudinal and transverse vortexes.The heat transfer is obviously enhanced.Larger rib height enhances the heat transfer by stronger side gap effects at the cost of larger pressure loss.The best overall heat transfer factorηis achieved in the case of h_(rib)/H=0.1,which increases by 204.5%comparing to the straight channel.When the rib interval is too small or too large,it approaches to the straight channel.The best overall heat transfer factorηis achieved in the case of L/p_(rib)=100,which increases by212.9%comparing to the straight channel.It is known the improvement in the geometry of the ribs,i.e.,the staggered-side-gap micro ribs,induces extra transverse vortex and improves the heat transfer performance more effectively.The research of this paper provides support for the cooling design of the SCRamjet.展开更多
目的:通过对神经侧支发芽过程中外源性神经生长因子对生长相关蛋白-43(gr owt h associ at ed pr ot ei n-43,GAP-43)的调控,探讨神经侧支发芽再生的机制。方法:SD大鼠共40只,建立胫腓神经端侧吻合模型,随机分为神经生长因子(nervegr ow...目的:通过对神经侧支发芽过程中外源性神经生长因子对生长相关蛋白-43(gr owt h associ at ed pr ot ei n-43,GAP-43)的调控,探讨神经侧支发芽再生的机制。方法:SD大鼠共40只,建立胫腓神经端侧吻合模型,随机分为神经生长因子(nervegr owt h f act or,NGF)组和生理盐水(SAL)组,各组又分为1周、2周、4周和8周组。切取吻合近端和远端神经纵切片标本,进行GAP-43的免疫组织化学反应,并结合计算机图像分析进行反应强度的半定量分析。结果:NGF组GAP-43表达显著增高。结论:应用NGF可以促进端侧吻合后神经侧支发芽。展开更多
A three-dimensional time-domain potential flow model is developed and applied to simulate the wave resonance in a gap between two side-by-side rectangular barges. A fourth-order predict-correct method is implemented t...A three-dimensional time-domain potential flow model is developed and applied to simulate the wave resonance in a gap between two side-by-side rectangular barges. A fourth-order predict-correct method is implemented to update free surface boundary conditions. The response of an up-wave barge is predicted by solving the motion equation with the Newmark-β method. Following the validation of the developed numerical model for wave radiation and diffraction around two side-by-side barges, the influence of up-wave barge motion on the gap surfaceresonance is investigated in two different locations of the up-wave barge relative to the back-wave barge at various frequencies. The results reveal that the freely floating up-wave barge significantly influences the resonance frequency and the resonance wave amplitude. Simultaneously, the up-wave barge located in the middle of the back-wave barge leads to a reduction in the resonance wave amplitude and motion response when compared with other configurations.展开更多
基金sponsored by the National Natural Science Foundation of China(No.51906207,No.U22B2091)the Young Elite Scientists Sponsorship Program by CAST(2021QNRC001)Technical Field Foundation(2021-JCJQ-JJ-0342)。
文摘SCRamjet is exposed to severe thermal environments during hypersonic flights,which poses a serious challenge to the engine cooling technology.Regenerative cooling with hydrocarbon fuel is considered promising,in which the hydrocarbon fuel flows through micro channels(200μm-3 mm)to absorb the combustion heat release.With strictly limited hydrocarbon fuel onboard,heat transfer deterioration and over-temperature are highly possible.In this paper,micro ribs with staggered side gaps are introduced and numerically studied to enhance the heat transfer.Compared with the straight channel and channel with straight micro ribs,the staggered side gaps alleviate the local low velocity zone and intensify the longitudinal and transverse vortexes.The heat transfer is obviously enhanced.Larger rib height enhances the heat transfer by stronger side gap effects at the cost of larger pressure loss.The best overall heat transfer factorηis achieved in the case of h_(rib)/H=0.1,which increases by 204.5%comparing to the straight channel.When the rib interval is too small or too large,it approaches to the straight channel.The best overall heat transfer factorηis achieved in the case of L/p_(rib)=100,which increases by212.9%comparing to the straight channel.It is known the improvement in the geometry of the ribs,i.e.,the staggered-side-gap micro ribs,induces extra transverse vortex and improves the heat transfer performance more effectively.The research of this paper provides support for the cooling design of the SCRamjet.
文摘目的:通过对神经侧支发芽过程中外源性神经生长因子对生长相关蛋白-43(gr owt h associ at ed pr ot ei n-43,GAP-43)的调控,探讨神经侧支发芽再生的机制。方法:SD大鼠共40只,建立胫腓神经端侧吻合模型,随机分为神经生长因子(nervegr owt h f act or,NGF)组和生理盐水(SAL)组,各组又分为1周、2周、4周和8周组。切取吻合近端和远端神经纵切片标本,进行GAP-43的免疫组织化学反应,并结合计算机图像分析进行反应强度的半定量分析。结果:NGF组GAP-43表达显著增高。结论:应用NGF可以促进端侧吻合后神经侧支发芽。
基金The Research Innovation Foundation of Tianjin Research Institute for Water Transportation Engineering of China under contract No.TKS 170215the Research Foundation of State Key Laboratory of Coastal and Offshore Engineering of Dalian University of Technology of China under contract No.TKS 170215
文摘A three-dimensional time-domain potential flow model is developed and applied to simulate the wave resonance in a gap between two side-by-side rectangular barges. A fourth-order predict-correct method is implemented to update free surface boundary conditions. The response of an up-wave barge is predicted by solving the motion equation with the Newmark-β method. Following the validation of the developed numerical model for wave radiation and diffraction around two side-by-side barges, the influence of up-wave barge motion on the gap surfaceresonance is investigated in two different locations of the up-wave barge relative to the back-wave barge at various frequencies. The results reveal that the freely floating up-wave barge significantly influences the resonance frequency and the resonance wave amplitude. Simultaneously, the up-wave barge located in the middle of the back-wave barge leads to a reduction in the resonance wave amplitude and motion response when compared with other configurations.
