Effect of motion path of downburst on wind-induced conductor swing in transmission line

Wenjuan Lou,Jiawei Wang,Yong Chen,Zhongbin Lv,Ming Lu Xu 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.3

In recent years, the frequency and duration of supply interruption in electric power transmission system due to flashover increase yearly in China. Flashover is usually associated with inadequate electric clearance and often takes place in extreme weathers, such as downbursts, typhoons and hurricanes. The present study focuses on the wind-induced oscillation of conductor during the process when a downburst is passing by or across a specified transmission line. Based on a revised analytical model recently developed for stationary downburst, transient three-dimensional wind fields of moving downbursts are successfully simulated. In the simulations, the downbursts travel along various motion paths according to the certain initial locations and directions of motion assumed in advance. Then, an eight-span section, extracted from a practical 500 kV ultra-high-voltage transmission line, is chosen. After performing a non-linear transient analysis, the transient displacements of the conductors could be obtained. Also, an extensive study on suspension insulator strings` rotation angles is conducted, and the electric clearances at different strings could be compared directly. The results show that both the variation trends of the transient responses and the corresponding peak values vary seriously with the motion paths of downburst. Accordingly, the location of the specified string, which is in the most disadvantageous situation along the studied line section, is picked out. And a representative motion path is concluded for reference in the calculation of each string`s oscillation for the precaution of wind-induced flashover under downburst.

PMDV-hop: An effective range-free 3D localization scheme based on the particle swarm optimization in wireless sensor network

( Wenjuan Wang ),( Yuwang Yang ),( Lei Wang ),( Wei Lu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.1

Location information of individual nodes is important in the implementation of necessary network functions. While extensive studies focus on localization techniques in 2D space, few approaches have been proposed for 3D positioning, which brings the location closer to the reality with more complex calculation consumptions for high accuracy. In this paper, an effective range-free localization scheme is proposed for 3D space localization, and the sensitivity of parameters is evaluated. Firstly, we present an improved algorithm (MDV-Hop), that the average distance per hop of the anchor nodes is calculated by root-mean-square error (RMSE), and is dynamically corrected in groups with the weighted RMSE based on group hops. For more improvement in accuracy, we expand particle swarm optimization (PSO) of intelligent optimization algorithms to MDV-Hop localization algorithm, called PMDV-hop, in which the parameters (inertia weight and trust coefficient) in PSO are calculated dynamically. Secondly, the effect of various localization parameters affecting the PMDV-hop performance is also present. The simulation results show that PMDV-hop performs better in positioning accuracy with limited energy.

Analytical Solutions of Deformation of Uplift Belled Group Piles considering Reinforcement Effect

Wenjuan Yao,Lu Xiao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.3

Up to now, the design method of uplift piles have still imitated the design of compressive piles, which results in that computation design theory is far behind of the engineering practice. As the interaction of piles has been very prominent and important in the deformation of pile groups, the deformation of the group piles has become the urgent issues in engineering applications. Based on the theory of elastic mechanics and principle of pile load transfer, it is derived that the nonlinear analytical expressions of deformation of uplift belled group piles considering reinforcement effect, and the specific calculation steps are given. The validity of the analytical method is verified through the comparison of the pictures, which consist of the calculated data of the analytical solution, the measured date of the model test and the results of finite element analysis. The results unveils that properties of soil, the expanded body of pile and the length of pile has impact on the deformation of uplift belled group piles considering the reinforcement effect significantly. With the increasing of elastic modulus of soil, the expanded body of pile and the length of pile, the uplift deformation of uplift belled group piles is reduced.

Effect of motion path of downburst on wind-induced conductor swing in transmission line

Lou, Wenjuan,Wang, Jiawei,Chen, Yong,Lv, Zhongbin,Lu, Ming Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.23 No.3

In recent years, the frequency and duration of supply interruption in electric power transmission system due to flashover increase yearly in China. Flashover is usually associated with inadequate electric clearance and often takes place in extreme weathers, such as downbursts, typhoons and hurricanes. The present study focuses on the wind-induced oscillation of conductor during the process when a downburst is passing by or across a specified transmission line. Based on a revised analytical model recently developed for stationary downburst, transient three-dimensional wind fields of moving downbursts are successfully simulated. In the simulations, the downbursts travel along various motion paths according to the certain initial locations and directions of motion assumed in advance. Then, an eight-span section, extracted from a practical 500 kV ultra-high-voltage transmission line, is chosen. After performing a non-linear transient analysis, the transient displacements of the conductors could be obtained. Also, an extensive study on suspension insulator strings' rotation angles is conducted, and the electric clearances at different strings could be compared directly. The results show that both the variation trends of the transient responses and the corresponding peak values vary seriously with the motion paths of downburst. Accordingly, the location of the specified string, which is in the most disadvantageous situation along the studied line section, is picked out. And a representative motion path is concluded for reference in the calculation of each string's oscillation for the precaution of wind-induced flashover under downburst.

Depression and Structural Factors Are Associated With Symptoms in Patients of Irritable Bowel Syndrome With Diarrhea

( Jia Lu ),( Lili Shi ),( Dan Huang ),( Wenjuan Fan ),( Xiaoqing Li ),( Liming Zhu ),( Jing Wei ),( Xiucai Fang ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2020 Journal of Neurogastroenterology and Motility (JNM Vol.26 No.4

Background/Aims A strong correlation between depression and irritable bowel syndrome with diarrhea (IBS-D) has been identified. The aim of this study is to identify the correlations among depression, structural factors, gastrointestinal (GI) and extra-GI symptoms, and efficacy of neuromodulators in patients with IBS-D. Methods Patients meeting the Rome III Diagnostic Criteria for IBS-D were enrolled. The intestinal symptoms and psychological states were evaluated using IBS-specific symptom questionnaires and Hamilton Depression Rating Scale. Results In total, 410 patients with IBS-D were enrolled, 28.8% (118/410) had comorbid depression. Patients with depression did not readily experience improvement in abdominal pain/discomfort after defecation, and had a higher prevalence of passing mucus, overlapping functional dyspepsia, and extra-GI symptoms. The structural factor “mental disorders” significantly correlated with main bowel symptom score and degree of pre-defecation abdominal pain/discomfort. No structural factor significantly correlated with bowel movements or stool form. Patients who had passing mucus, overlapping functional dyspepsia and extra-GI painful symptoms have higher score of “anxiety/somatization.” Patients with sexual dysfunction have higher score of “retardation symptoms.” In total, 28.3% of patients with IBS-D were prescribed neuromodulators. Baseline scores of “anxiety/somatization” and “retardation symptoms” positively correlated with improvement of diarrhea after paroxetine, and “sleep disturbances” positively correlated with improvement of abdominal pain/discomfort and diarrhea after mirtazapine. Conclusions Comorbid depression and higher scores of structural factors might aggravate GI and extra-GI symptoms other than bowel movements and stool form. Structural factors of Hamilton Depression Rating Scale correlated with efficacy of paroxetine and mirtazapine in patients with IBS-D. (J Neurogastroenterol Motil 2020;26:505-513)

Topological structure of Rubik’s cube mechanism and synthesis of the regular hexahedron Rubik’s cube mechanism

Dabao Fan,Daxing Zeng,Ya Liu,Wenjuan Lu,Yulei Hou,Zirong Zhou,Jianwen Guo 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4

This study investigates the factors affecting the topology of Rubik’s cube mechanism (RCM) and presents the synthesis theory of RCM. First, the revolute axis symmetry of the RCM is described and analyzed, and the general expression needed for the revolute axis to meet the symmetry is introduced. Next, the symmetry expression of the revolute pair contact surface (RPCS) of the RCM is given. The intersection between the RPCSs is analyzed via the adjacency matrix, and the adjacency matrix characteristics are given along with the motion characteristics of RCM. After determining the RPCS intersection, its topology is studied. Finally, the synthesis theory of RCM is presented, and the synthesis process and flowchart are proposed. The regular hexahedron RCMs with different topological structures are obtained after applying the synthesis theory. Hence, the theory proposed in this study provides strong theoretical support for the synthesis of other new RCMs.

Intracerebral Hemorrhage Progression Score: A Novel Risk Score to Predict Neurological Deterioration after Intracerebral Hemorrhage

Ruijun Ji,Linlin Wang,Feifei Ma,Wenjuan Wang,Yanfang Liu,Runhua Zhang,Dandan Wang,Jiaokun Jia,Hao Feng,Gaifen Liu,Yi Ju,Jingjing Lu,Xingquan Zhao 대한뇌졸중학회 2022 Journal of stroke Vol.24 No.2

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Study of the Non-Linearity on TiO2(0 0 1) Surface with Oxygen Defects: A First-Principles Study

Yuehua Dai,Xu Zhang,Chengzhi Ma,Zhiyong Pan,Feifei Wang,Wenjuan Lu,Jin Yang,Fei Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.8

First-principles plane-wave pseudopotential calculations were performed to study the energetics and electronic structures of oxygen defects on rutile TiO2(0 0 1). The influence of the material thickness on non-linearity (NL) was studied. With the increase in the thickness, the NL became stronger. Calculating the site-projected density of states by applying an external electric field showed that the NL of the bulk is due to the exchange of electrons between O 2p orbitals and Ti 3d orbitals. Finally, the influence of oxygen defects—oxygen vacancies (Vo), oxygen interstitials (Oi), and oxygen vacancies/oxygen interstitial (Vo + Oi) pairs (Frenkel pair defects)—on the NL of TiO2 was studied. These results demonstrate that the band gap (Eg) of TiO2 became gradually narrower as the electric field increased. The Stark effect and defects can lead to the splitting of degenerate energy levels. Stronger electric fields increase the band splitting and reduce Eg. With the increase in the Vo concentration, the decrease in the splitting amplitude and width of the energy level lead to weakening of the transfer of electrons between O and Ti atoms and optimizing the NL of TiO2. Therefore, the incorporation of Vo plays a significant role in improving the NL of TiO2.