| 1 | Shock-Wave/Rail-Fasteners Interaction for Two Rocket Sleds in the Supersonic Flow Regime显示文摘Rocket sleds belong to a category of large-scale test platforms running on the ground.The applications can be found in many fields,such as aerospace engineering,conventional weapons,and civil high-tech products.In the present work,shock-wave/rail-fasteners interaction is investigated numerically when the rocket sled is in supersonic flow conditions.Two typical rocket sled models are considered,i.e.,an anti-D shaped version of the rocket sled and an axisymmetric slender-body variant.The dynamics for Mach number 2 have been simulated in the framework of a dynamic mesh method.The emerging shock waves can be categorized as head-shock,tailing-shock and reflected-shock.An unsteady large-scale vortex and related shock dynamics have been found for the anti-D shaped rocket sled.However,a quasi-steady flow state exists for the slender-body shaped rocket sled.It indicates that the axisymmetric geometry is more suitable for the effective production of rocket sleds.With the help of power spectral density analysis,we have also determined the characteristic frequencies related to shock-wave/rail-fasteners interaction.Furthermore,a harmonic phenomenon has been revealed,which is intimately related to a shock wave reflection mechanism. | Bin Wang Jing Zheng Yuanyuan Yu Runmin Lv Changyue Xu | 2020 | Fluid Dynamics & Materials Processing2020，16，4： | 0 |
| 2 | Study on PRRSV Receptor Genes Differential Expression in Lung Tissues in Different Breeds of Pigs after Infecting with HP-PRRSV显示文摘[Objective] In order to study the susceptibility molecular mechanism of highly pathogenic porcine reproductive and respiratory syndrome virus( HPPRRSV) JXA1 isolate on Tibetan pig,Zangmei pig and Yorkshire pig. [Method]In the study,real-time quantitative RT-PCR method was established to compare and analyze the differential expression of five porcine reproductive and respiratory syndrome virus( PRRSV) receptor genes( HSPG2,SIGLEC1,CD163,VIM and NMMHC-II A) in lung tissues in Tibetan pig,Zangmei pig and Yorkshire pig before the challenge and at the 4^(th),7^(th) and 14 thdays after the challenge with JXA1 isolate. [Results] HSPG2 expression in Tibetan pig lung tissues increased significantly at the 4^(th) and 14 thdays after the challenge with JXA1( P < 0. 05),while decreased significantly at the 7^(th)day after the challenge( P < 0.05),HSPG2 expression in Zangmei pig lung tissues increased significantly at the 14 thday after the challenge( P < 0.05). SIGLEC1 expression in Tibetan pig lung tissues increased significantly at the 4^(th) and 14 thdays after the infection( P < 0.05),while SIGLEC1 expression in Yorkshire pig decreased significantly at the 4^(th),7^(th) and 14 thdays after the challenge( P < 0.05). CD163 expression in lung tissues of Tibetan pig and Zangmei pig both increased significantly at the 14 thday after the challenge( P < 0.05),while CD163 expression in lung tissues of Yorkshire pig decreased significantly at the 7^(th) and 14 thdays after the challenge( P < 0.05). VIM expression in lung tissues of Tibetan pig increased significantly at the 7^(th) day after the challenge( P < 0.05),while which of Yorkshire pig at the 7^(th) day after the challenge decreased significantly( P < 0.05). NMMHC-II A expression in lung tissues of Zangmei pig increased significantly at the 4^(th) day after the challenge( P < 0.05),and which of Yorkshire pig increased significantly at the 4^(th) and 14 thdays after the challenge( P < 0.05). [Conclusion]SIGLEC1 and VIM genes might be the potential key genes affecting the susceptibility of JXA1 isolate on Tibetan pig,Zangmei pig and Yorkshire pig. | Kang Runmin Ji Gaosheng Zeng Kai Lv Xuebin Yin Mingyu | 2017 | Animal Husbandry and Feed Science2017，9，4： | 0 |
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