Cumulative discrimination

Yaojun Li,Anthony Heath 한국사회학회 2018 한국사회학회 심포지움 논문집 Vol.2018 No.5

Control effect and mechanism investigation on the horizontal flow-isolating plate for PI shaped bridge decks’ VIV stability

Ke Li,Guowei Qian,Yaojun Ge,Lin Zhao,Jin Di 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.28 No.2

Vortex-Induced-Vibration (VIV) is one kind of the wind-induced vibrations, which may occur in the construction and operation period of bridges. This phenomenon can bring negative effects to the traffic safety or can cause bridge fatigue damage and should be eliminated or controlled within safe amplitudes. In the current VIV studies, one available mitigation countermeasure, the horizontal flow-isolating plate, shows satisfactory performance particularly in PI shaped bridge deck type. Details of the wind tunnel test are firstly presented to give an overall description of this appendage and its control effect. Then, the computational-fluid-dynamics (CFD) method is introduced to investigate the control mechanism, using two-dimensional Large-Eddy-Simulation to reproduce the VIV process. The Reynolds number of the cases involved in this paper ranges from 1×〖10〗^5 to 3×〖10〗^5, using the width of bridge deck as reference length. A field-filter technique and detailed analysis on wall pressure are used to give an intuitive demonstration of the changes brought by the horizontal flow-isolating plate. Results show that this aerodynamic appendage is equally effective in suppressing vertical and torsional VIV, indicating inspiring application prospect in similar PI shaped bridge decks.

Transcriptome-based Discovery of AP2/ERF tRanscription Factors and Expression Profiles Under Herbivore Stress Conditions in Bamboo (Bambusa emeiensis)

Yuanqiu Li,Chaobing Luo,Ying Chen,Ximeng Xiao,Chun Fu,Yaojun Yang 한국식물학회 2019 Journal of Plant Biology Vol.62 No.4

Bambusa emeiensis is one of the most economicallyimportant bamboos, yet the yield and quality of this bamboospecies continue to be challenged by insect herbivores. APETALA2/ethylene responsive factors (AP2/ERF) comprise alarge family of plant transcription factors regulating numerousbiological processes and playing critical roles in plantdefence responses. In the present study, 47 AP2/ERF genes wereidentified and classified in the B. emeiensis herbivore-inducedtranscriptome. Based on AP2 domain numbers, conservedamino-acid residues, motif analyses and phylogenetic trees andBeAP2/ERF proteins were grouped into four subfamilies,namely AP2, ERF, Dehydration-responsive-element-binding(DREB) and Soloist, and these subfamilies consisted of nine, 23,14 and 1 proteins, respectively. Amino-acid residue sequencesof the AP2 domain in B. emeiensis were conserved comparedwith those in Arabidopsis thaliana. Expression analyses revealedthat the treatment (herbivore damage) and control groupsexhibited different expression patterns, and majority of BeERF/DREB genes were significantly and differentially expressed inthe transcriptome, as verified using quantitative real-time PCR(qPCR). Finally, eight genes were selected for further PCRanalyses of tissue-specific expression, of which the four tissuesexhibited different expression patterns. Our data indicated thatthe genes encoding the ERF/DREB subfamily of B. emeiensisplay critical roles in its response to herbivores.

LncRNA XIST promotes carboplatin resistance of ovarian cancer through activating autophagy via targeting miR-506-3p/FOXP1 axis

Xiaoyan Xia,Zikui Li,Yaojun Li,Feng Ye,Xiaoming Zhou 대한부인종양학회 2022 Journal of Gynecologic Oncology Vol.33 No.6

Objective: Resistance to chemotherapy drugs makes ovarian cancer (OC) difficult to treat and ultimately kills patients. Long non-coding RNAs are closely related to carboplatin resistance in OC. In present study, we explored the role of lncRNA X-inactive specific transcript (XIST) on carboplatin resistance in OC. Methods: Cell viability, proliferation, and apoptosis were assessed through 2,5-diphenyl- 2H-tetrazolium bromide, colony formation, and flow cytometry assays, respectively. Microtubule-associated protein 1A/1B-light chain 3 expression was evaluated by immunofluorescence assay to analyze the cell autophagy. The interaction of XIST/ miR-506-3p or miR-506-3p/forkhead box protein P1 (FOXP1) was analyzed using RNA immunoprecipitation (RIP) and dual-luciferases reporter assays. The function of XIST/ miR-506-3p/FOXP1 axis in vivo was further confirmed by tumor xenograft study and immunohistochemistry. Results: The expression of XIST and FOXP1 increased while miR-506-3p decreased in OC and carboplatin resistance cells. XIST silencing repressed the proliferative and autophagic capacities of carboplatin resistance cells while promoted the apoptosis. XIST overexpression led to the opposite results. XIST targeted miR-506-3p and downregulated its expression. MiR-506-3p inhibition facilitated the proliferative and autophagic capacities while suppressed the apoptosis of cells, XIST knockdown reversed these effects. MiR-506-3p bound to FOXP1. XIST knockdown or miR-506-3p overexpression reversed the increase of cell proliferative and autophagic abilities and the decrease of apoptosis rate induced by FOXP1 overexpression. XIST affected autophagy and carboplatin resistance in vivo via regulating the miR-506-3p/FOXP1 axis. Conclusion: XIST knockdown inhibited autophagy and carboplatin resistance of OC through FOXP1/protein kinase B (AKT)/mammalian target of rapamycin pathway by targeting miR-506-3p.

Investigation of 3-D dynamic wind loads on lattice towers

Zou, Lianghao,Liang, Shuguo,Li, Q.S.,Zhao, Lin,Ge, Yaojun Techno-Press 2008 Wind and Structures, An International Journal (WAS Vol.11 No.4

In this paper, the along-wind, across-wind as well as torsional dynamic wind loads on three kinds of lattice tower models are investigated using the base balance technique in a boundary layer wind tunnel. The models were specially designed, and their fundamental frequencies in the directions of the three principal axes are still in the frequency range of the spectra of wind loads on lattice towers. In order to clear contaminations to the spectra of wind loads induced by model resonance, the generalized force spectra of the first mode of the models in along-wind, across-wind and torsional directions were derived based on measured base moments of the models. The RMS generalized force coefficients are also obtained by removing the contributions of model resonance. Finally, the characteristics of the 3-D dynamic wind loads, especially those of the across-wind dynamic loads, on the three kinds of lattice towers are presented and discussed.

Investigation of 3-D dynamic wind loads on lattice towers

Lianghao Zou,Shuguo Liang,Q. S. Li,Lin Zhao,Yaojun Ge 한국풍공학회 2008 Wind and Structures, An International Journal (WAS Vol.11 No.4

In this paper, the along-wind, across-wind as well as torsional dynamic wind loads on three kinds of lattice tower models are investigated using the base balance technique in a boundary layer wind tunnel. The models were specially designed, and their fundamental frequencies in the directions of the three principal axes are still in the frequency range of the spectra of wind loads on lattice towers. In order to clear contaminations to the spectra of wind loads induced by model resonance, the generalized force spectra of the first mode of the models in along-wind, across-wind and torsional directions were derived based on measured base moments of the models. The RMS generalized force coefficients are also obtained by removing the contributions of model resonance. Finally, the characteristics of the 3-D dynamic wind loads, especially those of the across-wind dynamic loads, on the three kinds of lattice towers are presented and discussed.

Prediction model of stall evolution stages in a centrifugal impeller based on characteristic analysis of the hydraulic torque of blades and support vector machine

Luan Shi,Zhuqing Liu,Wei Yang,Yaojun Li,Xiaodong Liu,Ran Tao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.10

If a centrifugal impeller is in deep stall, it requires a large amount of additional energy to break free. As such, it is crucial to study the prediction method of impeller stall and establish its relationship with force and torque. This study employs a computational fluid dynamics numerical simulation method to analyze the flow field within the impeller of a centrifugal pump, while monitoring the changes in hydraulic torque of the blades. By examining the impeller’s internal flow field characteristics and external (energy performance) characteristics curves under different working conditions, the stall process was classified into three stages: germination, transition and stabilization. The evolution of stall cells under different stall stages was also analyzed. We utilized time-frequency conversion and analysis to extract characteristic parameters from instantaneous hydraulic torque results generated under different working conditions. A more effective model for predicting impeller stall stages was built by virtue of support vector machine algorithm. The proposed model exhibits improved feasibility and effectiveness in comparison to traditional prediction methods. It is expected to have significant implications for stable operation monitoring and safety protection of centrifugal pumps.

Comparison of image masking methods for pump impeller blade region PIV experiments

Xiaodong Liu,Tingting Yan,Qiang Zhong,Zhuqing Liu,Fujun Wang,Yaojun Li,Wei Yang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

Due to the blade reflection effect when applying the PIV technology to the internal flow field measurement of rotating machinery, the blade area requires special treatment. In this paper, zero-value, particle image, random number, and mean-value masking methods are compared and analyzed based on particle images from the PIV challenge and rotating impeller. The peak significance and coordinates deviations are used as the masking effect evaluation criteria. The results indicate that an increase in the interrogation window masking area proportion causes a weakening of the PIV calculation particle cluster displacement peak value. The peak position is shifted, which leads to the wrong velocity vector. The masking area proportion should not be higher than 0.7, 0.5, 0.19, and 0.22 for mean-value, random number, zero-value, and particle image masking methods, respectively. The results show that flow field calculation results near the blade boundary are more accurate for mean-value masking.