Experimental and numerical investigation on post-earthquake fire behaviour of the circular concrete-filled steel tube columns

Yu-Hang Wang,Qi Tang,Mei-Ni Su,Ji-Ke Tan,Wei-Yong Wang,Yong-Sen Lan,Xiao-Wei Deng,Yong-Tao Bai,Wei Luo,Xiao-Hua Li,Jiu-Lin Bai 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.1

Post-earthquake fire is a common disaster which causes serious safety issues to infrastructures. This study aims to investigate the residual loading capacities of circular concrete-filled steel tube (CFST) columns under post-earthquake fire experimentally and numerically. The experimental programme contains two loading steps - pre-damage cyclic loading at room temperature and transient state tests with constant compression loads. Three finite element models are developed and validated against the test results. Upon validation, a total of 48 numerical results were generated in the parametric study to investigate the effects of thickness and strengths of steel tube, axial compression ratio and damage degree on the fire resistance of circular CFST columns. Based on the analysis on experimental and numerical results, the loading mechanism of circular CFST columns is discussed. A design method is proposed for the prediction of fire resistance time under different seismic pre-damage and compression loads. The predictions by the new method is compared with the newly generated experimental and numerical results and is found to be accurate and consistent with the mean value close to the unity and a coefficient of variation around 1%.

본태성 고혈압 환자에서 안지오텐신 II 수용체 차단제의 단기치료: 로자탄이 좌심실 확장기 기능 및 좌심실 질량, 대동맥의 경직도에 미치는 영향

이무용,한성식,류센,이명용,김영권,유선미 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.11

Compressive behavior of profiled double skin composite wall

Ying Qin,Yong-Wei Li,Yu-Sen Su,Xu-Zhao Lan,Yuan-De Wu,Xiang-Yu Wang 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.5

Profiled composite slab has been widely used in civil engineering due to its structural merits. The extension of this concept to the bearing wall forms the profiled composite wall, which consists of two external profiled steel plates and infill concrete. This paper investigates the structural behavior of this type of wall under axial compression. A series of compression tests on profiled composite walls consisting of varied types of profiled steel plate and edge confinement have been carried out. The test results are evaluated in terms of failure modes, load-axial displacement curves, strength index, ductility ratio, and load-strain response. It is found that the type of profiled steel plate has influence on the axial capacity and strength index, while edge confinement affects the failure mode and ductility. The test data are compared with the predictions by modern codes such as AISC 360, BS EN 1994-1-1, and CECS 159. It shows that BS EN 1994-1-1 and CECS 159 significantly overestimate the actual compressive capacity of profiled composite walls, while AISC 360 offers reasonable predictions. A method is then proposed, which takes into account the local buckling of profiled steel plates and the reduction in the concrete resistance due to profiling. The predictions show good correlation with the test results.

Structural behavior of the stiffened double-skin profiled composite walls under compression

Ying Qin,Yong-Wei Li,Xu-Zhao Lan,Yu-Sen Su,Xiang-Yu Wang,Yuan-De Wu 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.1

Steel-concrete composite walls have been proposed and developed for applications in various types of structures. The double-skin profiled composite walls, as a natural development of composite flooring, provide structural and architectural merits. However, adequate intermediate fasteners between profiled steel plates and concrete core are required to fully mobilize the composite action and to improve the structural behavior of the wall. In this research, two new types of fasteners (i.e., threaded rods and vertical plates) were proposed and three specimens with different fastener types or fastener arrangements were tested under axial compression. The experimental results were evaluated in terms of failure modes, axial load versus axial displacement response, strength index, ductility index, and load-strain relationship. It was found that specimen with symmetrically arranged thread rods sustained more stable axial strain than that with staggered arranged threaded rods. Meanwhile, vertical plates are more suitable for practical use since they provide stronger confinement to profiled steel plate and effectively prevent the steel plate from early local buckling, which eventually enhance the composite action and increase the axial compressive capacity of the wall. The calculation methods were then proposed and good agreement was observed between the test results and the predicted results.

Principles and symmetries of complexity in quantum field theory

Yang, Run-Qiu,An, Yu-Sen,Niu, Chao,Zhang, Cheng-Yong,Kim, Keun-Young Springer-Verlag 2019 European Physical Journal C Vol.79 No.2

태권도 수련생의 참여동기가 운동지속에 미치는 영향에서 만족도의 매개효과

유원등(Won-Deung Yu),추취센(Zhe-Sen Chu),장선미(Sun-Mi Jang),정영주(Young-Joo Jung),김용재(Yong-Jae Kim) 한국자료분석학회 2018 Journal of the Korean Data Analysis Society Vol.20 No.1

이 연구의 목적은 태권도 수련생의 참여동기가 운동지속에 미치는 영향에서 만족도의 매개효과를 규명하여 이를 통해 태권도 활성화 방안을 위한 기초 자료를 제공하는데 있다. 이러한 목적을 달성하기 위하여 2017년 11월부터 2017년 12월까지 태권도 수련생 373명 대상으로 실시한 설문조사를 통해 매개효과 검증을 위하여 3단계 회귀분석을 사용하였으며, Sobel의 검증 공식을 사용하여 통계적 유의성 검증 분석하여 다음과 같은 결론을 얻었다. 태권도 수련생의 참여동기가 만족도에 미치는 영향에서 참여동기 하위요인은 사교로 나타났다. 태권도 수련생의 참여동기가 운동지속에 미치는 영향에서 운동능력은 즐거움, 성취감, 외적과시, 운동습관은 사교, 건강체력, 외적과시, 운동환경은 기술발달, 외적과시로 나타났으며, 운동관심은 성취감, 사교, 외적과시로 나타났으며, 운동친구는 성취감, 컨디션, 사교로 나타났다. 태권도 수련생의 참여동기와 만족도가 운동지속에 미치는 영향에서 운동능력은 즐거움, 성취감, 외적과시, 만족도, 운동습관, 운동환경은 외적과시, 만족도로 나타났으며, 운동관심은 성취감, 만족도, 운동친구는 성취감, 컨디션, 사교, 만족도로 나타났다. 참여동기 중 사교가 운동친구에서 미치는 영향에서 만족도는 부분매개 역할을 통계적으로 유의하게 하는 것으로 나타났다. The purpose of this study is to clearly identify the mediating effect of satisfaction on the participation motivation of Taekwondo practitioners in terms of the duration and persistence of exercise and to provide basic data about practical and effective ways of utilizing Taekwondo. In order to achieve this goal, a three-step regression analysis was used to verify the mediating effects through a survey of the 373 Taekwondo practitioners from November 2017 to December 2017. Using Sobel s verification formula, the mediating effects were found to be statistically significant, resulting in the following conclusion. In terms of the influence of the motivation to participate on the continuity of practice among Taekwondo practioners, socialization was found to have a statistically significant influence as a mediating effect on satisfaction among the different motivations to participate.

Laser-processing of transparent solid materials for advanced photonic device applications

Feng Zhu,Rui Yang,Lei Wang,Yong-Sen Yu,Qi-Dai Chen,Hong-Bo Sun 한국생산제조학회 2012 한국생산제조시스템학회 학술발표대회 논문집 Vol.2012 No.10

We demonstrate the laser processing for fabrication of advanced photonic devices including fiber gratings and high transmittance biomimetic windows. The fiber gratings, including fiber Bragg gratings (FBGs) and long period fiber gratings (LPFGs), are fabricated in non-sensitized standard telecom single-mode fiber by femtosecond (fs) laser, making them hightemperature (1000 ℃) stable. The FBG written by fs laser combined with phase mask method is used for monitoring the thermal effect in fs laser interaction with silica glass. The peak temperature of the thermal impulse is estimated about 4800 ℃, which decays to around 500 ℃ in the pulse interval for irradiation of 1.1 mJ at repetition rate of 1 kHz. When the pulse energy and repetition rate increase in the fabrication process of FBGs, the fs-laser-induced grating regions extend from the fiber core to the cladding?air boundary due to the laser self-focusing. With the help of selective chemical etching of the laser modified grating regions, a microhole array structured FBG is formed, which is demonstrated in the application of simultaneous sensing for refractive index (RI) and temperature. For the fs laser direct writing of LPFGs, the period is 100 μm, making the total length of the LPFG only 5 mm. The LPFGs can couple the guided mode to high-order cladding modes of second-order diffraction, resulting in a high RI sensitivity of 5265 nm/RI unit in the RI range of 1.433 ∼ 1.443 and a low-temperature sensitivity of ?15.52 pm/℃ from 20 ℃ to 500 ℃. In addition, the high transmittance biomimetic windows are produced by direct laser interference ablation. The interfered laser beams are introduced into the surface of a bare optical substrate, where structured surfaces consisting of a micropillar array are produced by the multiple exposure of the two-beam interference ablation. As an example of the application, zinc sulfide substrates are processed with this technology.

Genetic diversity and population structure of the amylolytic yeast Saccharomycopsis fibuligera associated with Baijiu fermentation in China

Wang Ju-Wei,Han Pei-Jie,Han Da-Yong,Zhou Sen,Li Kuan,He Peng-Yu,Zhen Pan,Yu Hui-Xin,Liang Zhen-Rong,Wang Xue-Wei,Bai Feng-Yan 한국미생물학회 2021 The journal of microbiology Vol.59 No.8

The amylolytic yeast Saccharomycopsis fibuligera is a predominant species in starters and the early fermentation stage of Chinese liquor (Baijiu). However, the genetic diversity of the species remains largely unknown. Here we sequenced the genomes of 97 S. fibuligera strains from different Chinese Baijiu companies. The genetic diversity and population structure of the strains were analyzed based on 1,133 orthologous genes and the whole genome single nucleotide polymorphisms (SNPs). Four main lineages were recognized. One lineage contains 60 Chinese strains which are exclusively homozygous with relatively small genome sizes (18.55–18.72 Mb) and low sequence diversity. The strains clustered in the other three lineages are heterozygous with larger genomes (21.85–23.72 Mb) and higher sequence diversity. The genomes of the homozygous strains showed nearly 100% coverage with the genome of the reference strain KPH12 and the sub-genome A of the hybrid strain KJJ81 at the above 98% sequence identity level. The genomes of the heterozygous strains showed nearly 80% coverage with both the sub-genome A and the whole genome of KJJ81, suggesting that the Chinese heterozygous strains are also hybrids with nearly 20% genomes from an unidentified source. Eighty-three genes were found to show significant copy number variation between different lineages. However, remarkable lineage specific variations in glucoamylase and α-amylase activities and growth profiles in different carbon sources and under different environmental conditions were not observed, though strains exhibiting relatively high glucoamylase activity were mainly found from the homozygous lineage.