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RISS 인기검색어
- 검색키워드
- 저자 : Shi Yongjie (검색결과 5 건)
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Analysis of Genetic Diversity of Forteen Species of Caragana in Gansu Province of China
Shi Yongjie,Guo Qiang 한국초지조사료학회 2009 한국초지조사료학회 학술대회논문집 Vol.2009 No.08
Ten cpSSR markers were used to detected genetic diversity and relationship among fourteen species of Caragana. The genetic diversity was 0.860 to 2.138, with an average of 1.258. The effective number of alleles for each cpSSR locus ranged from 2.051to 7.407, with an average of 3.530.Ten cpSSR primers detected totally 92 polymorphic loci, the value of allelic polymorphism information content (PIC) ranged from 0.512 to 0.865, on an average, 0.671 per primer. The value of genetic similarity (GS) indexes among fourteen species of Caragana varied from 0.51 to 0.93, on an average of 0.77. These indicated that the genetic diversity at the genomic level of the selected source germplasm was rich, and was representative of the diversity of the germplasms, in general. Cluster analysis showed that fourteen Species of Caragana tested in this study could be clustered into four groups, cpSSR analyzed inter-genetic relationship was almost consistent with traditional morphologic result.
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Zhiyuan Hu,Guohua Xu,Yongjie Shi 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.4
Rotors with active flap control have considerable potential in reducing vibration and noise and improving aerodynamic performance. However, due to the movement of the flap, there are unavoidable gaps between the components that will lead to significant changes in the aerodynamic characteristics. Moreover, considering the difficulties in motion modeling and the accuracy of the simulation of the flow field in such a narrow gap, carrying out related research is challenging; thus, there has been inadequate targeted research, and that which does exist requires supplementation. To carry out this challenging flow field simulation, the overset assembly algorithm proposed by the author in previous research is adopted in the present study. It is used to successfully assemble the narrow gap, and the accuracy of the simulation is fully verified by comparing the results with the actual experimental results and a grid study. Furthermore, to compensate for the lack of research and experiments on the gap effect, cases considering a complete range of gap widths from an absence of a gap to a width of 10% of the chord length are set up and carried out under the following three case groups: steady cases with a fixed trailing-edge deflection angle, unsteady cases in which only the trailing-edge flap is flapping, and full-motion cases characterized by the periodic flap of the main airfoil and the trailing-edge flap. The results show that the gap increases the drag of the trailing-edge flap and decreases aerodynamic efficiency, especially at low speeds and high angles of attack. Nevertheless, when the gap is unavoidable, there is a range of the gap width that makes unapparent the decrease of aerodynamic efficiency. Moreover, the decrease of aerodynamic efficiency can be reduced as much as possible by a well-designed gap region geometry to ensure that the airfoil and the trailing-edge flap fit together when moving.
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Research on a Robust Overset Grid Method for Load Calculation of Coaxial Rotor
Yang Yucheng,Guohua Xu,Shi Yongjie 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.3
In this paper, a robust overset grid assembly technology suitable for the coaxial rotor in flow field calculation is established and two kinds of interpolation boundaries including so-called Max-hole boundary and Max-overlap boundary are proposed. The technology is applied to the computational fluid dynamics method based on the Reynolds-averaged Navier–Stokes equation to realize flow field simulation and aerodynamic performance calculation of coaxial rotor and overcome orphan point problem. Firstly, the pressure distribution of 30p30n airfoil is calculated and verified by experimental data. Through the high-efficient trimming method, the input of AH-G Helicopter rotor is obtained. The aerodynamic performance of AH-1G helicopter rotor is calculated and compared with experimental data. Finally, the input of coaxial rotor is also obtained by trimming method and flow field of the coaxial rotor in hover and the low advance ratio is calculated. The results show that the chimera method based on the Max-hole chimera boundary can be applied to obtain the aerodynamic characteristics of the coaxial rotor, effectively capturing the blade-vortex interference between rotors and rotor itself while aerodynamic performance cannot be accurately simulated under the Max-overlap chimera boundary.
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Investigation of a Virtual Blade Method for Aerodynamic and Acoustic Prediction of Helicopter Rotors
Chi Zhang,Guohua Xu,Yongjie Shi 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.2
A virtual blade method (VBM) combining the unsteady momentum source model with the computational fluid dynamics solver is applied in this work. The momentum source term is employed to replace the effect of the rotor blade on the air in the unsteady Reynolds-averaged Navier–Stokes equations, and the unsteady characteristics of the rotor flow field are accurately captured without body-fitted grids. The rotor aeroacoustic computation model is then combined with the Ffowcs Williams and Hawkings (FW–H) equation. Taking the Caradonna–Tung rotor, GIT rotor fuselage model, and AH-1/OLS rotor model as examples, the aeroacoustic computation effectiveness for blade tip vortex capturing in hover and rotor/fuselage aerodynamic interactions is validated by available experimental data. The results show that the VBM can accurately simulate the rotor wake, unsteady load, and aerodynamic noise at a low computational cost. Compared with the body-fitted grid method, the flow field computation time of the VBM is reduced by 3/4, and the amount of data for VBM/FW–H acoustic postprocessing is reduced by more than 90%.
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Qin Xin,Wan Jianbo,Zhang Qi,Zhang Yongjie,Yu Huangzhong,Shi Shengwei 한국탄소학회 2023 Carbon Letters Vol.33 No.3
Graphitic carbon nitride (g-C3N4) has attracted extensive attention in energy storage due to its suitable and tunable bandgap, high chemical/thermal stability, earth abundance and environmental friendliness. However, its conductivity should be improved to work as the electrode materials in supercapacitors. In this report, we have prepared a two-dimensional composite (CN-PANI) based on g-C3N4 and polyaniline (PANI) by in-situ polymerization, which can be efficiently applied as electrode material for supercapacitors. The introduction of PANI can increase the conductivity of the electrode, and the porous structure of g-C3N4 can provide enough channels for the transport of electrolyte ions and improve the electrode stability. As a result, the obtained CN-PANI demonstrates excellent specific capacitance (234.0 F g−1 at 5 mV/s), good rate performance and high cycling stability (86.2% after 10,000 cycles at 50 mV/s), showing great potential for high-rate supercapacitors.
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