Influence of Microstructure and Mechanical Properties on Formability in High Strain Rate Rolled AZ31 Magnesium Alloy Sheets

Fubao Liu,Xiao Liu,Biwu Zhu,Hui Yang,Gang Xiao,Mingyue Hu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

High strain-rate rolling (≥ 10 s−1) has been successfully employed to produce AZ31 magnesium alloy sheets to a high reductionof 82% with a fine grain structure in a single pass. The rolled sheets inevitably undertake various forming processessuch as press and deep forming in the fabrication stage. To investigate the formability, the Erichsen tests were carried out onhigh strain rate rolled AZ31 magnesium alloy sheets at room temperature. The relationship among mechanical properties,microstructure and formability were investigated. The crack behavior during Erichsen tests was also studied. It was foundthat the formability was related to the lowest in-plane tensile strengthen and dislocation density of initial microstructure. The competitive relationship between micro-crack and twinning/shear bands would also influence the formability of highstrain rate rolled magnesium alloy sheets. Deformed shear band with substaintial twins prohibits the crack extension andenhances strengthen of materials in front of crack tip.

"五四"何以失精神

劉慧軍 한국중국문화학회 2000 中國學論叢 Vol.9 No.-

5·4운동은 중국 역사상 위대한 사상변혁운동이다. 5·4운동이 제창한 "立人"사상은 당시뿐만 아니라 현재에 있어서도 중국문화의 발전과 변화에 중요한 의의를 지니고 있다. 그러나 여러 가지 원인 때문에 5·4정신은 잊혀졌다. 본고는 정치와 문화적 측면에서 5·4정신이 잊혀지게 된 원인을 검토한 바, 다음 3가지가 주된 원인으로 작용하였다고 분석하였다. 첫째, 중국전통문화의 뿌리가 확고하여 민주사상이 단시간 내에 확립될 수 없었다. 둘째, 정치의 막강한 흡인력이 신문화운동 발전에 영향을 미쳐 지식인이 문화적 사고를 포기하여, 중국의 사상계몽이 시작되자마자 중단되었다. 셋째, 5·4운동 후 권력자의 남용이 5·4정신을 잊혀지게 하는 중요한 원인이 되었다.

Magnetic Behaviour of Composites Containing Polyacrylate Coated CoFe₂O₄

Hui Liu,Feng Xu,Liangchao Li,Yuping Wang,Haizhen Qiu 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

A Study on the Different Characteristics for Information Consumption in Urban and Rural Residents - Focusing on China's Jilin Province -

Hui-Shu Liu,Gi-Young Chung,Hyung-Ho Kim 한국융합학회 2020 한국융합학회논문지 Vol.11 No.7

본 연구의 목적은 농촌 주민과 도시 주민 간의 정보 소비의 특성을 조사하고 평가하는 것이다. 본 연구에서는 중국 길림성에 위치한 15개 도시와 농촌 지역 거주자에 대해 121개의 정보소비 문항으로 구성된 설문과 심층 인터뷰 를 통해 데이터를 수집했으며, 985개의 유효 응답을 SPSS 23.0을 이용하여 분석하였다. 도시와 농촌 거주자를 대상으 로 연령별, 가구형태 및 성별에 따른 정보소비 특성을 분석한 결과, 연령과 성별, 연령과 가구형태, 가족형태와 성별 사이에 상호작용이 큰 것을 알 수 있었다. 본 연구는 도시와 시골 주민들 사이의 정보 서비스 격차를 줄이고 정보 소비 의 잠재력을 활용하는 데 기여할 수 있다. 이번 연구는 중국 길림성 주민만을 대상으로 분석했다는 한계가 있으며 향후 조사 범위를 확대할 필요가 있다. The purpose of this study is to investigate and evaluate the characteristics of information consumption between rural and urban residents. In this study, the data were collected through a survey and in-depth interview consisting of 121 information consumption questions for the residents of 15 cities and rural areas located in Jilin Province, China, and 985 effective responses were analyzed using SPSS 23.0. Analysis of information consumption characteristics by age, type of household and gender for urban and rural residents showed that there was a large interaction between age and gender, age and type of household, type of household and gender. This study can contribute to narrowing the information service gap between urban and rural residents and utilizing the potential of information consumption. The study is limited to analyzing only residents of Jilin Province in China and needs to expand the scope of future investigations.

Study on a stretchable, fiber-shaped, and TiO₂ nanowire array-based dye-sensitized solar cell with electrochemical impedance spectroscopy method

Liu, Guicheng,Wang, Hui,Wang, Manxiang,Liu, Wenbing,Anugrah Ardhi, Ryanda Enggar,Zou, Dechun,Lee, Joong Kee Elsevier 2018 ELECTROCHIMICA ACTA Vol.267 No.-

<P><B>Abstract</B></P> <P>A spring-like Ti@TiO<SUB>2</SUB> nanowire array wire has been introduced into a stretchable fiber-shaped dye-sensitized solar cell (FDSSC) as a photoanode to achieve high flexibility and elasticity in this paper. Given the TiO<SUB>2</SUB> layer, which was prepared by a hydrothermal reaction in the optimized NaOH concentration of 2.5 mol L<SUP>−1</SUP>, with a 1D structure and high adhesion between the TiO<SUB>2</SUB> nanowire array and the Ti wire substrate, the novel FDSSC still possesses photoelectric conversion efficiency retention rates of approximately 97.00% and 95.95% after bending to a radius of 1.0 cm and stretching to 100% strain, respectively. EIS result shows the degradation mechanism of the FDSSC photoelectric performance: the bending test leads to more terrible electron combination; the stretching operation increases the internal resistance and charge-transfer resistance at the counter electrode. Moreover, it's worth noting that, this is the first time to show a 100%-stretching degree in the FDSSC research field so far.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A fiber-shaped, stretchable, TiO<SUB>2</SUB> nanowire array-based DSSC was reported firstly. </LI> <LI> Using EIS analysis method to analyse effect of bending and stretching on FDSSC performance. </LI> <LI> Photoelectric conversion efficiency retention rate of 95.95% after stretching to 100% strain. </LI> <LI> High flexibility with 97.00% performance retention rate at bending radius of 1 cm. </LI> </UL> </P>

Multiaxial Fatigue Life Prediction Based on High-Cycle Uniaxial Fatigue Test of Steel Pipe Weldments with Welding Defects

Hui Liu,Xiu-wen Lv,Shi-chao Chen,Qiang Zhou,Piao Zhou,Wei-lian Qu 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.1

Welding defects are unavoidable for welded structures, which can lead to fatigue damage even under the random wind load with small amplitude. It is therefore necessary to explore the effect of welding defect on the fatigue properties of welded steel pipes. Three groups of welded steel pipe specimens were designed according to welding defect conditions, i.e. specimens without welding defect (Group I), specimens with incomplete fusion (Group II), and specimens with welding porosity (Group III). Uniaxial tension–compression and torsion high-cycle fatigue tests were carried out. S–N curves of uniaxial tension–compression and torsion tests were obtained by cyclic loading with equal stress amplitude. The test results show that the high-cycle fatigue strength of weldments is obviously lower than that of base metal with the same strength under uniaxial tension–compression and torsion loading. In addition, the welding defects result in a decrease in fatigue strength, while the decrease extent by welding porosity is greater than that by incomplete fusion. Finally, because of the inherent multiaxial loading characteristics of welded structures, the high-cycle multiaxial fatigue life of steel pipe weldments was also predicted by using the modified Wöhler curve method based on the uniaxial fatigue test results. It can be found that when the stress amplitude is constant, the fatigue life of welded steel pipe decreases and the modified Wöhler curves move downward more quickly with the increase of damage parameter defined as the ratio of normal stress amplitude to shear stress amplitude on the critical plane, which means that normal stress amplitude will accelerate the cracks growth and result in faster failure of the weld materials.

Application of Fast Lifting Wavelet Transform to the Estimation of Harmonic for Shunt Active Power Filters

Hui Liu,Guohai Liu,Yue Shen 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

This paper presents a new harmonic measurement scheme based on lifting wavelet transform (LWT) for shunt active power filters (APFs). As one of methods to build second-generation wavelets, LWT can be easy to achieve in time domain for its original bit location calculation. And it could lessen calculation complexity and depress course due to its particular structure, compared with first generation wavelet algorithm (WT). The theoretical and simulative results have verified that the novel LWT approach can abstract harmonic components currents effective with short transient time even when source voltages are asymmetrical distorted. It can accurately detect harmonic components more quickly than classical WT algorithm.

Nickel hydroxide/chemical vapor deposition-grown graphene/nickel hydroxide/nickel foam hybrid electrode for high performance supercapacitors

Liu, Shude,Yin, Ying,San Hui, Kwan,Hui, Kwun Nam,Lee, Su Chan,Chan Jun, Seong Elsevier 2019 ELECTROCHIMICA ACTA Vol.297 No.-

<P><B>Abstract</B></P> <P>Rational design of electrode structures has been recognized as an effective strategy to improve the electrochemical performance of electrode materials. Herein, we demonstrate an integrated electrode in which nickel hydroxide (Ni(OH)<SUB>2</SUB>) nanosheets are deposited on both sides of chemical vapor deposition-grown graphene on Ni foam, which not only effectively optimizes electrical conductivity of Ni(OH)<SUB>2</SUB>, but also accommodates the structural deformation associated with the large volume change upon cycling. The synthesized Ni(OH)<SUB>2</SUB>/graphene/Ni(OH)<SUB>2</SUB>/Ni foam electrode exhibits a high specific capacity of 991 C g<SUP>−1</SUP> at a current density of 1 A g<SUP>−1</SUP>, which is higher than the theoretical specific capacity of additive sum of Ni(OH)<SUB>2</SUB> and graphene, and retains 95.4% of the initial capacity after 5000 cycles. A hybrid supercapacitor is constructed by using Ni(OH)<SUB>2</SUB>/graphene/Ni(OH)<SUB>2</SUB>/Ni foam as the positive electrode and activated carbon on Ni foam as the negative electrode, which achieves a maximum energy density of 49.5 W h kg<SUP>−1</SUP> at a power density of 750 W kg<SUP>−1</SUP>, and excellent cycling lifespans with 89.3% retention after 10000 cycles at 10 A g<SUP>−1</SUP>.</P>

중국 전통 희곡 요소를 활용한 인물 삽화

Liu Hui,Young Hwan Pan,Sun Li 한국서비스디자인학회 2021 한국서비스디자인학회 학술대회자료집 Vol.2021 No.-

The Analysis of the Origin of Confucianism of Song Dynasty in the Confucianism of Jin Dynasty -On the Spread and Influence of the Confucianism of Song Dynasty in the Jin Dynasty

( Liu Hui ),( Shao Hanming ) 성균관대학교 유교문화연구소 2011 儒敎文化硏究(中文版) Vol.0 No.15

金代儒學的學術思想直接源自漢唐經學和宋代儒學。與漢唐經學相較, 宋學尤其是南宋理學在金代傳播范圍有限, 流傳時間也較爲短暫, 但是其對金代儒學本身的影響, 在某種意義上甚至超過了漢唐經學。《宋元學案》列有宋代90 多個學案, 其中對金代儒學産生直接的、較大影響的學派有蘇氏蜀學、二程洛學、朱熹闽學。本文將分別就三者在金代的流傳及其與金代儒學的關系作以簡要梳理, 以期對金代儒學的學術源流主要是宋學源流有一個淸晳的把握。 Lin The academic thought of the Confucianism of Jin Dynasty origins directly from the Confucian Classics of the Han Dynasty and Tang Dynasty and the Confucianism of Song Dynasty. Comparing with the Confucian Classics of the Han Dynasty and Tang Dynasty, the Confucianism of Song Dynasty, especially the Confucianism of Nan Song Dynasty is limited in the spread range and it spreads in a relatively short time, but its influence is even more than the the Confucian Classics of the Han Dynasty and Tang Dynasty. The Case Studies of Song Dynasty and Yuan Dynasty lists more than 90 cases of Song Dynasty, the schools which influence the Confucianism of Jin Dynasty directly and greatly include Shu Shi Shu Xue, Er Cheng Luo Xue and Zhu Xi Min Xue. In this paper, I will research on the spread of the above three in the Jin Dynasty and its relationship with the Confucianism of Jin Dynasty in order to get a clear understanding of the fact that the academic origin of the Confucianism of Jin Dynasty is from the origin of the Confucianism of Song Dynasty. [Article in Chinese]