SINCE the days when Zimbabwe was still Rhodesia, the Southern African nation has had troubled relations with the international community. On November 11, 1965, the white minority govern- ment of Rhodesia, led by Ian S...SINCE the days when Zimbabwe was still Rhodesia, the Southern African nation has had troubled relations with the international community. On November 11, 1965, the white minority govern- ment of Rhodesia, led by Ian Smith, declared a Unilateral Decla- ration of Independence （UDI） from the colonial power of Great Britain.展开更多
In order to investigate the impact characteristic of an aircraft landing on water,a computational fluid dynamics(CFD)simulation is conducted to explore the slamming characteristics of the NACA TN 2929 A model.The flow...In order to investigate the impact characteristic of an aircraft landing on water,a computational fluid dynamics(CFD)simulation is conducted to explore the slamming characteristics of the NACA TN 2929 A model.The flow around the model is solved by using Reynolds-averaged Navier-Stokes equations with the shear stress transport(SST)k—ωturbulence model,based on finite volume method(FVM).The free surface is captured by using the volume of fluid(VOF)method,and the aircraft impact process is realized with help of overset mesh technology.Then,the effects of horizontal and vertical velocities and initial pitch angle on the slamming load,attitude change,impact pressure and flow field evolution are investigated.The results reveal that the horizontal velocity has a considerable influence on whether the aircraft’s horizontal tail hits the water,and further affects the maximum vertical load as well as the maximum pitch angle throughout the impact process.The vertical velocity determines the slamming load before the horizontal tail strikes the water,while the horizontal velocity has a significant effect on the load after the horizontal tail hits the water.A smaller initial pitch angle results in not only a heavier slamming load but also a more dramatic change of the posture after the aircraft impacts the water.The impact pressure of the aircraft is maximized at the junction of the approaching surface of the fuselage and the free surface.In some cases,the pressure is also concentrated on the undersurface of the horizontal tail.展开更多
This article analyzes two literary works by the Czech writer, Julius Zeyer （1841-1901）, and Lu Xun （1881-1936） by elaborating upon two different myths concerning the Archer Hou Yi. These myths were presented by th...This article analyzes two literary works by the Czech writer, Julius Zeyer （1841-1901）, and Lu Xun （1881-1936） by elaborating upon two different myths concerning the Archer Hou Yi. These myths were presented by the missionary and Sinologist William Frederick Mayers in The Chinese Reader＇s Manual： A Handbook of Biographical, Historical, Mythological and General Literary References （1874）, and other Chinese sources. Zeyer highlighted the first myth, which was connected with the Emperor Yao and showed Hou Yi shooting arrows at the nine suns appearing together in the heavens, and Lu Xun preferred the second myth, where the Archer Yi rebelled against the Emperor Tai Kang, whom he drove from the Capital, and later was killed by Han Zhuo. The myth of Chang E who flew to the moon is described only by Lu Xun.展开更多
文摘SINCE the days when Zimbabwe was still Rhodesia, the Southern African nation has had troubled relations with the international community. On November 11, 1965, the white minority govern- ment of Rhodesia, led by Ian Smith, declared a Unilateral Decla- ration of Independence （UDI） from the colonial power of Great Britain.
基金supported by the National Natural Science Foundation of China(Grant No.52061135107)This work was supported by the Liao Ning Revitalization Talents Program(Grant No.XLYC1908027)+1 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.DUT20TD108,DUT20LAB308 and DUT20RC(3)025)the opening project of State Key Laboratory of Explosion Science and Technology(Grant No.KFJJ21-09M).
文摘In order to investigate the impact characteristic of an aircraft landing on water,a computational fluid dynamics(CFD)simulation is conducted to explore the slamming characteristics of the NACA TN 2929 A model.The flow around the model is solved by using Reynolds-averaged Navier-Stokes equations with the shear stress transport(SST)k—ωturbulence model,based on finite volume method(FVM).The free surface is captured by using the volume of fluid(VOF)method,and the aircraft impact process is realized with help of overset mesh technology.Then,the effects of horizontal and vertical velocities and initial pitch angle on the slamming load,attitude change,impact pressure and flow field evolution are investigated.The results reveal that the horizontal velocity has a considerable influence on whether the aircraft’s horizontal tail hits the water,and further affects the maximum vertical load as well as the maximum pitch angle throughout the impact process.The vertical velocity determines the slamming load before the horizontal tail strikes the water,while the horizontal velocity has a significant effect on the load after the horizontal tail hits the water.A smaller initial pitch angle results in not only a heavier slamming load but also a more dramatic change of the posture after the aircraft impacts the water.The impact pressure of the aircraft is maximized at the junction of the approaching surface of the fuselage and the free surface.In some cases,the pressure is also concentrated on the undersurface of the horizontal tail.
文摘This article analyzes two literary works by the Czech writer, Julius Zeyer （1841-1901）, and Lu Xun （1881-1936） by elaborating upon two different myths concerning the Archer Hou Yi. These myths were presented by the missionary and Sinologist William Frederick Mayers in The Chinese Reader＇s Manual： A Handbook of Biographical, Historical, Mythological and General Literary References （1874）, and other Chinese sources. Zeyer highlighted the first myth, which was connected with the Emperor Yao and showed Hou Yi shooting arrows at the nine suns appearing together in the heavens, and Lu Xun preferred the second myth, where the Archer Yi rebelled against the Emperor Tai Kang, whom he drove from the Capital, and later was killed by Han Zhuo. The myth of Chang E who flew to the moon is described only by Lu Xun.
