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        Numerical investigation on radial impeller induced vortex rope in draft tube under partial load conditions

        Yongyan Ni,Renqing Zhu,Xiao Zhang,Zhong-yong Pan 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

        The vortex rope phenomena appearing in a draft tube under partial load operations were investigated. The efforts were carried out by using a homogeneous equilibrium vapor-liquid two-phase model and a blending SST turbulence model, and the former takes account of the weak compressibility of mixed media. The vortex rope phenomena were induced by the radial impeller and three kinds of flow regimes were illustrated. Vortex rope was visible at some conditions and it displayed various patterns, while no obvious vortex rope was found under some conditions. It was found that the plant cavitation number determines that whether the vortex rope was visible or invisible. An interesting profile was that a secondary vortex filament ring entwining the vortex rope appeared clearly near the design condition. Both flow structures and pressure characteristics were studied to depict the vortex mechanism and the characteristics of the η-σ curves. Further analysis found that the shedding frequency of the vortex ring is similar with that of the precession movement.

      • KCI등재

        Numerical analysis and experimental investigation on impeller-volute match characteristics

        Yongyan Ni,Xiao Wang,Zhong-yong Pan 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11

        Impeller-volute match is an essential issue of pump dynamic characteristics and it is very important for the understanding of the flow features in the pumps and the vibration symptom of the device. Advanced performance diagnosis and smart operation and maintenance are profoundly dependent upon the perceiving of the rotor-stator interaction. In order to describe the interaction more comprehensively, the related flows were described by both theoretical approach and numerical simulations. Both velocity distribution and area-ratio aspect were theoretically indicated and a critical condition of non-shock criterion was proposed. Numerical efforts were therefore carried out and unveiled the flow regime as well as the pressure variations. The frequency properties of the pressure variations indicated that both the shaft rotation frequency and the blade passing frequency (BPF) dominated the contents, which implicitly demonstrated the accurate simulation work. Vibration content was lastly tested to validate the numerical results and the rotor-stator interaction effects. No significant shaft rotation contents appeared in the tested vibration signals due to the precise shaft support. Other than the blade passing frequency, both sub-synchronous and super-synchronous contents of BPFs appear under nearly all conditions. It is noted that the experimental means used here are able to get sufficient information of the pump operation.

      • Potential Study Perspectives on Mechanisms and Correlations Between Adiposity and Malignancy

        Lu, Kun,Song, Xiao-Lian,Han, Shi-Long,Wang, Chang-Hui,Zhong, Ni,Qi, Li-Feng Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

        Adiposity is a well-recognized risk factor of type 2 diabetes and cardiovascular disease, and recently there is increasing evidence that excess body weight is an avoidable cause of cancer, including gastrointestinal, endometrial, esophageal adenocarcinoma, colorectal, postmenopausal breast, prostate, and renal malignancies. The mechanisms whereby adiposity is associated with tumor development remains not well understood. There are some most studied hypothesized mechanisms such as, high levels of insulin and free levels of insulin-like growth factors, sex hormones, adipocytokines, and inflammatory cytokines, adiposity-induced hypoxia, and so on. The potential mechanisms and conclusions in adiposity associated with increased risk for developing malignancy, and the underlying cellular and molecular mechanisms will be studied very well in the near future.

      • KCI등재

        Utility of DNA barcoding for identification of common Vespa species (Hymenoptera: Vespidae) from Yunnan, China

        Wang Ming‐Ming,Yin Peng‐Kai,Tang Ya‐Ni,Yang Zi‐Zhong,Xiao Huai,Zhang Cheng‐Gui,Yang Yin‐He,Yang Da‐Song 한국곤충학회 2022 Entomological Research Vol.52 No.3

        As traditional Chinese medicine and edible insects, Ve s p a hornets have high economic value and huge market demand. Hornet breeding has become an important way to increase the income of mountain farmers in China, but the limitation of traditional identification methods has become the bottleneck of the modern development of hornet resources. In this study, a simple and reliable method for the molecular identification of typical hornets from Yunnan was successfully established. In the NCBI database, DNA sequences of hornet samples were aligned as Vespa analis, Ve s p a b a s a l i s , Vespa velutina, Vespa mandarinia, Ve s p a m a g n i f i c a , Ve s p a b i n g h a m i , Ve s p a s o r o r by BLAST search. The efficiency of the PCR amplification of mitochondrial cytochrome C oxidase I (COI) gene sequences in all samples was 100% by using the optimized program. Moreover, a reference database for DNA barcodes of Vespa materials in Yunnan was constructed. This study provided a successful example for the identification of local insects of Yunnan and will be helpful to the development of wasp resources.

      • Knowledge, Perceptions and Acceptability of HPV Vaccination among Medical Students in Chongqing, China

        Fu, Chun-Jing,Pan, Xiong-Fei,Zhao, Zhi-Mei,Saheb-Kashaf, Michael,Chen, Feng,Wen, Ying,Yang, Chun-Xia,Zhong, Xiao-Ni Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.15

        Objectives: To evaluate medical students' knowledge of HPV and HPV related diseases and assess their attitudes towards HPV vaccination. Methods: A total of 605 medical undergraduates from Chongqing Medical University in China were surveyed using a structured and pretested questionnaire on HPV related knowledge. Results: Some 68.9% of the medical students were females, and mean age was 21.6 (${\pm}1.00$) years. Only 10.6% correctly answered more than 11 out of 14 questions on HPV related knowledge, 71.8% being willing to receive/advise on HPV vaccination. Female students (OR: 2.69; 95% CI: 1.53-4.72) and students desiring more HPV education (OR: 4.24; 95% CI: 1.67-10.8) were more willing to accept HPV vaccination. HPV vaccination acceptability was observed to show a positive association with HPV related knowledge. Conclusions: Our survey found low levels of HPV related knowledge and HPV vaccination acceptability among participating medical students. HPV education should be systematically incorporated into medical education to increase awareness of HPV vaccination.

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