Study on the Buckling Behaviour of Cold-Formed Angles in Transmission Towers

Fengli Yang,Junke Han,Jingbo Yang,Zhenbao Li 한국강구조학회 2011 International Journal of Steel Structures Vol.11 No.4

Considering the structural characteristics of transmission towers, four sections of cold-formed angles with different slenderness ratios and constrained types were selected for the experimental and numerical study. Experiments and finite element analysis for the ultimate loads of the compression cold-formed angles were carried out. The finite element model well predicts the buckling behaviour of the cold-formed members. For the axial compression members, the load-strain curves as well as the ultimate loads were analyzed, and the experimental ultimate loads were compared with those of calculated by the applicable standards. It shows that the applicable standards aren’t adaptive to the strength design of the compression cold-formed members in transmission towers. Through the analysis of the experimental and FEA results, the fitting curve of the stability coefficients for the cold-formed members in transmission towers was determined. The ultimate loads calculated by the fitting curve are well agreed with the experimental values, especially for the members with relatively low slenderness ratios. Some modification suggestions were proposed for the calculation of the ultimate load for the axial compression cold-formed angle. Experimental analysis on the cold-formed members of the other five constrained types was completed, and the modification formulas of the slenderness ratios for members of different constrained types were obtained.

Wind tunnel tests on wind loads acting on steel tubular transmission towers under skewed wind

FengLi Yang,Huawei Niu 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.35 No.2

Steel tubular towers are commonly used in UHV and long crossing transmission lines. By considering effects of the model scale, the solidity ratio and the ratio of the mean width to the mean height, wind tunnel tests under different wind speeds on twenty tubular steel tower body models and twenty-six tubular steel cross-arm models were completed. Drag coefficients and shielding factors of the experimental tower body models and cross-arm models in wind directional axis for typical skewed angles were obtained. The influence of the lift forces on the skewed wind load factors of tubular steel tower bodies was evaluated. The skewed wind load factors, the wind load distribution factors in transversal and longitudinal direction were calculated for the tubular tower body models and cross-arm models, respectively. Fitting expressions for the skewed wind load factors of tubular steel bodies and cross-arms were determined through nonlinear fitting analysis. Parameters for skewed wind loads determined by wind tunnel tests were compared with the regulations in applicable standards. Suggestions on the drag coefficients, the skewed wind load factors and the wind load distribution factors were proposed for tubular steel transmission towers.

Two case studies on structural analysis of transmission towers under downburst

FengLi Yang,HongJie Zhang 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.22 No.6

Downbursts are of great harm to transmission lines and many towers can even be destroyed. The downburst wind field model by Chen and Letchford was applied, and the wind loads of two typical transmission towers in inland areas and littoral areas were calculated separately. Spatial finite element models of the transmission towers were established by elastic beam and link elements. The wind loads as well as the dead loads of conductors and insulators were simplified and applied on the suspension points by concentrated form. Structural analysis on two typical transmission towers under normal wind and downburst was completed. The bearing characteristics and the failure modes of the transmission towers under downburst were determined. The failure state of tower members can be judged by the calculated stress ratios. It shows that stress states of the tower members were mainly controlled by 45 degree wind load. For the inland areas with low deign wind velocity, though the structural height is not in the highest wind velocity zone of downburst, the wind load under downburst is much higher than that under normal wind. The main members above the transverse separator of the legs will be firstly destroyed. For the littoral areas with high deign wind velocity, the wind load under downburst is lower than under normal wind. Transmission towers are not controlled by the wind loads from downbursts in design process.

Two case studies on structural analysis of transmission towers under downburst

Yang, FengLi,Zhang, HongJie Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.22 No.6

Downbursts are of great harm to transmission lines and many towers can even be destroyed. The downburst wind field model by Chen and Letchford was applied, and the wind loads of two typical transmission towers in inland areas and littoral areas were calculated separately. Spatial finite element models of the transmission towers were established by elastic beam and link elements. The wind loads as well as the dead loads of conductors and insulators were simplified and applied on the suspension points by concentrated form. Structural analysis on two typical transmission towers under normal wind and downburst was completed. The bearing characteristics and the failure modes of the transmission towers under downburst were determined. The failure state of tower members can be judged by the calculated stress ratios. It shows that stress states of the tower members were mainly controlled by 45 degree wind load. For the inland areas with low deign wind velocity, though the structural height is not in the highest wind velocity zone of downburst, the wind load under downburst is much higher than that under normal wind. The main members above the transverse separator of the legs will be firstly destroyed. For the littoral areas with high deign wind velocity, the wind load under downburst is lower than under normal wind. Transmission towers are not controlled by the wind loads from downbursts in design process.

A Research on the Construction of golf Course and Its Surrounding Area in China from the Perspective of “Ecology-Production-Life” Space

Haolong Xu(Haolong Xu),Fengli Sun(Fengli Sun) 동북아경상학회 2022 동북아경상연구 Vol.3 No.2

Purpose - This paper aims to analyze and provide solutions to the current problems of golf courses and surrounding land in China, guided by the concept of “ecology-production-living” space and using scientific and objective analysis while selecting appropriate indicators. This paper hopes to optimize the utilization value of golf courses and their surrounding space in China and provide a new and feasible basis and method for the rational development and popularization of golf in China based on the country’s actual situation. Design/Methodology/Approach - Combining with domestic and foreign theories and research, this paper analyzed the “ecology-production-life” space problems in golf course and its surrounding area, and draws a series of corresponding conclusions or strategies. Findings - This paper studies the strategic measures for the sustainable development of Chinese golf from the perspective of “ecology-production-life” space are obtained. Research Implications - In terms of the managerial implication of this paper, this study provides a new feasible basis and method for the rational development and popularization of golf in China. It also has certain practical significance for realizing the rural revitalization strategy.

K-Anonymity Algorithm Using Encryption for Location Privacy Protection

Jinying Jia,Fengli Zhang 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.9

In this paper, we solved a location privacy protection in location-based services (LBS) where the mobile user had to report her exact location information to an LBS provider for the purpose of obtaining her wished services. Location invisible had been well proposed and researched to defend user privacy. However, as the nature of the insecure wireless net environment the user’s location information may still be uncovered. We presented a k-anonymity algorithm using encryption for location privacy protection that can improve security of LBS system by encrypting the information transmitted by wireless. The experimental results evidence that the processing time is acceptable in current low-level devices.

Non-deterministic K-anonymity Algorithm Based Untrusted Third Party for Location Privacy Protection in LBS

Jinying Jia,Fengli Zhang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.9

Stable feature screening for ultrahigh dimensional data

Peng Lai,Fengli Song,Yufei Gao 한국통계학회 2019 Journal of the Korean Statistical Society Vol.48 No.2

This paper is concerned with the stable feature screening for the ultrahigh dimensional data. To deal with the ultrahigh dimensional data problem and screen the important features, a set-averaging measurement is proposed. The model averaging technique and the conditional quantile method are used to construct the weighted set-averaging feature screening procedure to identify the relationships between the possible predictors and the response variable. The proposed screening method is model free, stable and possesses the sure screening property under some regular conditions. Some Monte Carlo simulations and a real data application are conducted to evaluate the performance of the proposed procedure.

The Clinical, Molecular, and Mechanistic Basis of RUNX1 Mutations Identified in Hematological Malignancies

Yokota, Asumi,Huo, Li,Lan, Fengli,Wu, Jianqiang,Huang, Gang Korean Society for Molecular and Cellular Biology 2020 Molecules and cells Vol.43 No.2

RUNX1 plays an important role in the regulation of normal hematopoiesis. RUNX1 mutations are frequently found and have been intensively studied in hematological malignancies. Germline mutations in RUNX1 cause familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML). Somatic mutations of RUNX1 are observed in various types of hematological malignancies, such as AML, acute lymphoblastic leukemia (ALL), myelodysplastic syndromes (MDS), myeloproliferative neoplasm (MPN), chronic myelomonocytic leukemia (CMML), and congenital bone marrow failure (CBMF). Here, we systematically review the clinical and molecular characteristics of RUNX1 mutations, the mechanisms of pathogenesis caused by RUNX1 mutations, and potential therapeutic strategies to target RUNX1-mutated cases of hematological malignancies.

Activation of Phosphatidylinositol 3-Kinase/AKT/Snail Sig-nalling Pathway Contributes to Epithelial-Mesenchymal Transition-Induced Multi-Drug Resistance to Sorafenib in Hepatocellular Carcinoma Cells

( Jiejie Dong ),( Bo Zhai ),( Weihua Sun ),( Fengli Hu ),( Hao Cheng ),( Lishan Xu ),( Jun Xu ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Sorafenib, an orally available kinase inhibitor, is the standard first-line systemic drug for advanced hepatocellular carcinoma (HCC), and it exerts potent inhibitory activity against epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR) by inhibiting mitogen- activated protein kinase (MAPK) signalling in HCC. However, after long-term exposure to sorafenib, HCC cells exhibit EMT and resistance to sorafenib. The activation of AKT by sorafenib is thought to be responsible for the development of these characteristics. The present study aims to examine the underlying mechanism and seek potential strategies to reverse this resistance and the progression to EMT. Methods: Cell viability assay; Transfection of siRNA; Construction of the pCDNA3.1-Snail eukaryotic expression vector and transfection; Cell migration and invasion assays; Western blot analysis; Real-time reverse transcription PCR. Results: Sorafenib-resistant cells showed increased metastatic and invasive ability, with a higher expression of P-glycoprotein (P-gp), compared with the parental cells. This phenomenon was at least partially due to EMT and the appearance of MDR in sorafenib-resistant HCC cells. Moreover, MDR was a downstream molecular event of EMT. Silencing Snail with siRNA blocked EMT and partially reversed the MDR, thereby markedly abolishing invasion and metastasis in sorafenib- resistant HCC cells, but silencing of MDR1 had no effect on the EMT phenotype. Additionally, HCC parental cells that were stably transfected with pCDNA3.1-Snail exhibited EMT and MDR. Two sorafenib- resistant HCC cell lines, established from human HCC HepG2 and Huh7 cells, were refractory to sorafenib-induced growth inhibition but were sensitive to MK-2206, a novel allosteric AKT inhibitor. Thus, the combination of sorafenib and MK-2206 led to significant reversion of the EMT phenotype and P-gp-mediated MDR by downregulating phosphorylated AKT. Conclusions: These findings underscore the significance of EMT, MDR and enhanced PI3K/AKT signalling in sorafenib-resistant HCC cells.