Computing turbulent far-wake development behind a wind turbine with and without swirl

Hu, Yingying,Parameswaran, Siva,Tan, Jiannan,Dharmarathne, Suranga,Marathe, Neha,Chen, Zixi,Grife, Ronald,Swift, Andrew Techno-Press 2012 Wind and Structures, An International Journal (WAS Vol.15 No.1

Modeling swirling wakes is of considerable interest to wind farm designers. The present work is an attempt to develop a computational tool to understand free, far-wake development behind a single rotating wind turbine. Besides the standard momentum and continuity equations from the boundary layer theory in two dimensions, an additional equation for the conservation of angular momentum is introduced to study axisymmetric swirl effects on wake growth. Turbulence is simulated with two options: the standard ${\kappa}-{\varepsilon}$ model and the Reynolds Stress transport model. A finite volume method is used to discretize the governing equations for mean flow and turbulence quantities. A marching algorithm of expanding grids is employed to enclose the growing far-wake and to solve the equations implicitly at every axial step. Axisymmetric far-wakes with/without swirl are studied at different Reynolds numbers and swirl numbers. Wake characteristics such as wake width, half radius, velocity profiles and pressure profiles are computed. Compared with the results obtained under similar flow conditions using the computational software, FLUENT, this far-wake model shows simplicity with acceptable accuracy, covering large wake regions in far-wake study.

Computing turbulent far-wake development behind a wind turbine with and without swirl

Yingying Hu,Siva Parameswaran,Jiannan Tan,Suranga Dharmarathne,Neha Marathe,Zixi Chen,Ronald Grife,Andrew Swift 한국풍공학회 2012 Wind and Structures, An International Journal (WAS Vol.15 No.1

Modeling swirling wakes is of considerable interest to wind farm designers. The present work is an attempt to develop a computational tool to understand free, far-wake development behind a single rotating wind turbine. Besides the standard momentum and continuity equations from the boundary layer theory in two dimensions, an additional equation for the conservation of angular momentum is introduced to study axisymmetric swirl effects on wake growth. Turbulence is simulated with two options: the standard k-ε model and the Reynolds Stress transport model. A finite volume method is used to discretize the governing equations for mean flow and turbulence quantities. A marching algorithm of expanding grids is employed to enclose the growing far-wake and to solve the equations implicitly at every axial step. Axisymmetric far-wakes with/without swirl are studied at different Reynolds numbers and swirl numbers. Wake characteristics such as wake width, half radius, velocity profiles and pressure profiles are computed. Compared with the results obtained under similar flow conditions using the computational software, FLUENT, this far-wake model shows simplicity with acceptable accuracy, covering large wake regions in far-wake study.

Transforming Shanghai into an International Financial Center: Mechanism and Benefits

( Yingying Hu ) 고려대학교 법학연구원 2017 The Asian Business Lawyer Vol.19 No.-

In addition to the Hong Kong international financial center, the establishment of Shanghai as an IFC is viewed as a clear sign of China`s ambition to play a more significant role in the international financial market, help Chinese enterprises raise domestic funds more easily by directing China`s surplus savings to GDP growth, and stimulate Chinese financial institutional reform.¹ Whereas the benefits of financial development through the establishment of an IFC are significant, the cost associated with this financial development is also high. Chinese legislators and policy makers need to be aware of potential speculative financial transactions and the risk arising from market manipulation by financial institutions.² Given the fact that Chinese financial institutions are mostly politically powerless, a government-led IFC project would effectively put external pressure on domestic financial reform. Nevertheless, the enormous benefits obtained from the Shanghai IFC will justify the costs, and driving the government to positively loosen its controls on the financial market. To minimize the potential cost incurred from the financial globalization, the Chinese government should identify essential sectors of the economy that need additional protection through tax, direct subsidy or other means when it seizes direct controls from the financial market.

Long-chain bases from Cucumaria frondosa inhibit adipogenesis and regulate lipid metabolism in 3T3-L1 adipocytes

Yingying Tian,Shiwei Hu,Hui Xu,Jingfeng Wang,Changhu Xue,Yuming Wang 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.6

This study aims to investigate anti-adipogenic effects of long-chain bases from Cucumaria frondosa (Cf-LCBs) in vitro. Results showed that Cf-LCBs inhibited adipocyte differentiation and the expressions of CCAAT/enhancer binding proteins (C/EBPs) and peroxisome proliferators-activated receptor γ (PPARγ). Cf-LCBs increased β-catenin mRNA and nuclear translocation and increased its target genes, cyclin D1 and c-myc. Cf-LCBs enhanced fizzled and lipoprotein-receptor-related protein5/6 (LRP5/6) expressions, whereas wingless-type MMTV integration site10b (WNT10b) and glycogen syntheses kinase 3β (GSK3β) remained unchanged. Cf-LCBs also reduced adipogenesis and recovered WNT/β-catenin signaling in the cells suffering from 21H7, a β-catenin inhibitor. In addition, Cf-LCBs decreased triglyceride content and the expressions of lipogenesis genes. Cf-LCBs increased FFA levels and the expressions of lipidolytic factors. Cf-LCBs promoted the phosphorylation of adenosinemonophosphate- activated protein kinase (AMPK) and acetyl-CoA carboxylase. These findings indicate that Cf-LCBs inhibit adipogenesis through activation of WNT/β-catenin signaling and regulate lipid metabolism via activation of AMPK pathway.

CDK1 promotes the proliferation of melanocytes in Rex rabbits

Dai Yingying,Hu Shuaishuai,Bai Shaocheng,Li Jiali,Yang Naisu,Zhai Pin,Zhao Bohao,Chen Yang,Wu Xinsheng 한국유전학회 2022 Genes & Genomics Vol.44 No.10

Background: The fur color constitutes one of the most important economic characteristics of fur animals and is determined by the content of melanin. A previous study has shown that the cyclin-dependent kinase 1 (CDK1) is a member of the protein kinase family, involved in forming the color of the fur in Rex rabbits. However, its effect on the melanocytes remains unclear. Objective: This study aimed to provide evidence for the role of CDK1 in melanogenesis. Methods: This study measured the expression of CDK1 in Rex rabbit skins of six coat colors using qRT-PCR. The CDK1-mediated regulation of the pigmentation-related genes and cyclin-dependent kinases were analyzed. The melanin content, proliferation, and apoptosis of the melanocytes were analyzed using the NaOH, CCK8, and Annexin V-FITC methods. Results: The CDK1 expression in the skin of the rex rabbits with different coat colors was found to be regular, and the expression level was found to be the highest in the skin of the black rex rabbits (P < 0.05). The overexpression/knockdown of CDK1 was found to significantly increase/decrease the melanin content in the melanocytes (P < 0.01). Besides, CDK1 was found to significantly promote the proliferation of the melanocyte and inhibit apoptosis (P < 0.01). Furthermore, the overexpression of CDK1 was found to significantly affect the expression of the other melanin-related genes like TYR, PMEL, DCT, as well as the mRNA expression of the cyclin-dependent kinases CDK4, CDK6, CDK8, CCNB1. Conclusions: The results indicated that CDK1 can serve as a key gene regulating melanogenesis, melanocyte proliferation, and apoptosis, providing a new theoretical basis for studying the mechanism by which the different colors of the fur evolve in mammals.

Long-chain bases from Cucumaria frondosa inhibit adipogenesis and regulate lipid metabolism in 3T3-L1 adipocytes

Tian, Yingying,Hu, Shiwei,Xu, Hui,Wang, Jingfeng,Xue, Changhu,Wang, Yuming 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.6

This study aims to investigate anti-adipogenic effects of long-chain bases from Cucumaria frondosa (Cf-LCBs) in vitro. Results showed that Cf-LCBs inhibited adipocyte differentiation and the expressions of CCAAT/enhancer binding proteins (C/EBPs) and peroxisome proliferators-activated receptor ${\gamma}(PPAR{\gamma})$. Cf-LCBs increased ${\beta}-catenin$ mRNA and nuclear translocation and increased its target genes, cyclin D1 and c-myc. Cf-LCBs enhanced fizzled and lipoprotein-receptor-related protein5/6 (LRP5/6) expressions, whereas wingless-type MMTV integration site10b (WNT10b) and glycogen syntheses kinase $3{\beta}(GSK3{\beta})$ remained unchanged. Cf-LCBs also reduced adipogenesis and recovered WNT/${\beta}-catenin$ signaling in the cells suffering from 21H7, a ${\beta}-catenin$ inhibitor. In addition, Cf-LCBs decreased triglyceride content and the expressions of lipogenesis genes. Cf-LCBs increased FFA levels and the expressions of lipidolytic factors. Cf-LCBs promoted the phosphorylation of adenosinemonophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase. These findings indicate that Cf-LCBs inhibit adipogenesis through activation of WNT/${\beta}-catenin$ signaling and regulate lipid metabolism via activation of AMPK pathway.

ON SOLUTIONS TO SOME NONLINEAR DIFFERENCE AND DIFFERENTIAL EQUATIONS

Chen, Wei,Hu, Pei-Chu,Zhang, Yingying Korean Mathematical Society 2016 대한수학회지 Vol.53 No.4

In this paper, we study entire solutions of some nonlinear difference equations and transcendental meromorphic solutons of some nonlinear differential equations. Our results generalize the results due to [11], [17].

Observation and characterization of the effect of electron cyclotron waves on toroidal rotation in EAST L-mode discharges

CHEN, Jun,HU, Ruiji,LYU, Bo,WANG, Fudi,WANG, Xiaojie,XU, Handong,LI, Yingying,FU, Jia,YIN, Xianghui,WU, Dajun,LIU, Fukun,ZANG, Qing,LIU, Haiqing,SHI, Yuejiang,MAO, Shifeng,YU, Yi,WAN, Baonian,YE, Miny IOP Publishing 2017 Plasma science & technology Vol.19 No.10

A lightweight and flexible CNT/Fe3O4 composite with high electromagnetic interference shielding performance

Zhuo Chao,Yingying Yu,Fang Lei,Dongmei Hu 한국탄소학회 2021 Carbon Letters Vol.31 No.1

Lightweight and flexible electromagnetic interference (EMI) shielding materials are in great demand for wearable EMI device. In the present work, lightweight and flexible carbon nanotube (CNT)/ferroferric oxide ( Fe3O4) composite film was made through a feasible chemical vapor deposition process for CNT film synthesis, followed by a hydrothermal reduction process for Fe3O4 coating. In the as-prepared composite, CNT film and Fe3O4 particles work as conductive skeleton and strong magnetic particle, respectively. The as-prepared composite film shows a novel EMI shielding effectiveness (SE) of 91 dB in the X-band, a small thickness of 0.09 mm and a low density of 0.86 g/cm3, which is superior to most of the carbonbased EMI materials.

Fishbone Oscillations in the Experimental Advanced Superconductivity Tokamak

Liqing Xu,Liqun Hu,Yi Yuan,Yingying Li,Guo-Qiang Zhong,Hai-Qing Liu,Kaiyun Chen,Tong-Hui Shi,Yan-Min Duan 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.6

A fishbone oscillation was observed in the neutral beam injection plasma at Experimental Ad- vanced Superconductivity Tokamak (EAST). This m = 1/n = 1 (m, n: poloidal, toroidal mode numbers, respectively) typical internal kink mode travels in the ion-diamagnetism direction in the poloidal section with a rotation speed close to the ion diamagnetic drift frequency. A high thermal plasma beta and high amounts of energetic ions are necessary for the mode to develop. Fishbone oscillations can expel heavy impurities in the core, which favors sustaining a high-performance plasma. The born frequency of the fishbone oscillation is the ion diamagnetic drift frequency and the chirping down of the frequency during the initial growth phase is the result of a drop in ion- diamagnetic drift frequency. The excitation energy is thought to be due to the thermal plasma pressure gradient; however, the development of a fishbone oscillation is related to energetic ions. A fishbone oscillation was observed in the neutral beam injection plasma at Experimental Advanced Superconductivity Tokamak (EAST). This m = 1/n = 1 (m, n: poloidal, toroidal mode numbers, respectively) typical internal kink mode travels in the ion-diamagnetism direction in the poloidal section with a rotation speed close to the ion diamagnetic drift frequency. A high thermal plasma beta and high amounts of energetic ions are necessary for the mode to develop. Fishbone oscillations can expel heavy impurities in the core, which favors sustaining a high-performance plasma. The born frequency of the fishbone oscillation is the ion diamagnetic drift frequency and the chirping down of the frequency during the initial growth phase is the result of a drop in ion- diamagnetic drift frequency. The excitation energy is thought to be due to the thermal plasma pressure gradient; however, the development of a fishbone oscillation is related to energetic ions.