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Qian Li,Aihong Ji,Huan Shen,Renshu Li,Kun Liu,Xiangming Zheng,Lida Shen,Qingfei Han 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.2
The design of a flapping-wing aircraft is mainly inspired by flying animals: to improve the lift and efficiency of flapping-wing aircraft, their wings, an essential part of the aircraft, mimic the configuration and geometric characteristics of flying animals. Herein, we conducted wing parameter optimization experiments by changing the wing-vein layout, aspect ratio (AR), surface area, and leading-edge-rod flexibility of a flapping-wing aircraft having four wings with double wing clap-and-fling effects. The AR and leading-edge-rod flexibility significantly influenced the lift through the aircraft’s clap-and-fling effects. Analyzing the wing deformation and lift fluctuation revealed that the leading-edge-rod flexibility delayed the trailing-edge separation during clapping, resulting in a large lift at the beginning of peeling. A pentagonal wing of 155-mm wing length, 5.0 AR, a 100-mm breaking point, and an 80-mm wing-vein convergence point at the leading-edge-rod near the wing root was deemed the optimal wing design. This optimal wing design was used to build a 30 g flapping-wing aircraft for an outdoor flight test, which could fly for 6.5 min with a 4.5-g load, thus demonstrating the developed prototype’s potential for autonomous flight.
Testicular Characteristics and the Block to Spermatogenesis in Mature Hinny
Han, Hongmei,Wang, Aihong,Liu, Liming,Zhao, Gaoping,Su, Jie,Wang, Biao,Li, Yunxia,Zhang, Jindun,Wu, Baojiang,Sun, Wei,Hu, Shuxiang,Li, Shuyu,Zhao, Lixia,Li, Xihe Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.6
Most hinnies (female donkey${\times}$male horse) and mules (female horse${\times}$male donkey) are sterile with few reports of equine fertile hybrids. The main cause of this sterility is thought to be a meiotic block to spermatogenesis and oogenesis. This study compared the developmental features of the testes and a histological analyses of spermatogenesis in a male hinny with those of a normal, fertile stallion and Jack donkey. Hinny testes showed a thicker tunica albuginea, fewer blood vessels and more connective tissue in the testis parenchyma than those of the stallion and Jack donkey. Although the mean number of seminiferous tubules was significantly higher in stallion and hinny than Jack donkey (p<0.01), the mean proportion of seminiferous tubules was lower in the hinny (p<0.01) which resulted in a smaller diameter of seminiferous tubules. The mean number of spermatogonia and spermatocytes per unit area were significantly lower in hinny testis (p<0.01) and no spermatids or mature spermatozoa cells were found during immunofluorescent analyses. These results indicated that defects in seminiferous tubule development and structure occur in the testis of hinnies. Furthermore, most spermatogonia and spermatocytes cease development in synapsis during mid-meiosis of spermatocytes, which results in a block to spermatogenesis that prevents the formation of spermatids and matured spermatozoa during meiosis in male hinnies.