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.

Experimental study on vortex-induced motions of a semi-submersible with square columns and pontoons at different draft conditions and current incidences

Mingyue Liu,Longfei Xiao,Haining Lu,Xiaolong Xiao 대한조선학회 2017 International Journal of Naval Architecture and Oc Vol.9 No.3

The Vortex-induced Motions (VIM) phenomenon of semi-submersibles is relevant for the fatigue life of moorings and risers. Model tests regarding the VIM behavior of a semi-submersible with four square columns were conducted in order to investigate the effects of the current incidence and the aspect ratio of the immerged column. The experimental results show that the largest transverse amplitudes are around 70% of the column width at 30 and 45 incidences in a range of reduced velocities from 5 to 8 when the aspect ratio of the immerged column is 1.90. The largest yaw motion occurs at 0 incidence with the peak value around 4.5. Similar characteristics of the VIM response are observed for the semi-submersible with aspect ratios of 1.90 and 1.73. When the aspect ratio decreases 50% to 0.87, 30% decrease in the peak transverse amplitudes can be seen.

Experimental investigation of flow characteristics around four square-cylinder arrays at subcritical Reynolds numbers

Liu, Mingyue,Xiao, Longfei,Yang, Lijun The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.5

The Deep Draft Semi-Submersible (DDS) concepts are known for their favourable vertical motion performance. However, the DDS may experience critical Vortex-Induced Motion (VIM) stemming from the fluctuating forces on the columns. In order to investigate the current-induced excitation forces of VIM, an experimental study of flow characteristics around four square-section cylinders in a square configuration is presented. A number of column spacing ratios and array attack angles were considered to investigate the parametric influences. The results comprise flow patterns, drag and lift forces, as well as Strouhal numbers. It is shown that both the drag and lift forces acting on the cylinders are slightly different between the various L/D values, and the fluctuating forces peak at L/D = 4.14. The lift force of downstream cylinders reaches its maximum at around ${\alpha}=15^{\circ}$. Furthermore, the flow around circular-section-cylinder arrays is also discussed in comparison with that of square cylinders.

Experimental study on vortex-induced motions of a semi-submersible with square columns and pontoons at different draft conditions and current incidences

Liu, Mingyue,Xiao, Longfei,Lu, Haining,Xiao, Xiaolong The Society of Naval Architects of Korea 2017 International Journal of Naval Architecture and Oc Vol.9 No.3

The Vortex-induced Motions (VIM) phenomenon of semi-submersibles is relevant for the fatigue life of moorings and risers. Model tests regarding the VIM behavior of a semi-submersible with four square columns were conducted in order to investigate the effects of the current incidence and the aspect ratio of the immerged column. The experimental results show that the largest transverse amplitudes are around 70% of the column width at $30^{\circ}$ and $45^{\circ}$ incidences in a range of reduced velocities from 5 to 8 when the aspect ratio of the immerged column is 1.90. The largest yaw motion occurs at $0^{\circ}$ incidence with the peak value around $4.5^{\circ}$. Similar characteristics of the VIM response are observed for the semi-submersible with aspect ratios of 1.90 and 1.73. When the aspect ratio decreases 50% to 0.87, 30% decrease in the peak transverse amplitudes can be seen.

Experimental investigation of flow characteristics around four square-cylinder arrays at subcritical Reynolds numbers

Mingyue Liu,Longfei Xiao,Lijun Yang 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.5

The Deep Draft Semi-Submersible (DDS) concepts are known for their favourable vertical motion performance. However, the DDS may experience critical Vortex-Induced Motion (VIM) stemming from the fluctuating forces on the columns. In order to investigate the current-induced excitation forces of VIM, an experimental study of flow characteristics around four square-section cylinders in a square configuration is presented. A number of column spacing ratios and array attack angles were considered to investigate the parametric influences. The results comprise flow patterns, drag and lift forces, as well as Strouhal numbers. It is shown that both the drag and lift forces acting on the cylinders are slightly different between the various L/D values, and the fluctuating forces peak at L/D = 4.14. The lift force of downstream cylinders reaches its maximum at around α = 15°. Furthermore, the flow around circularsection- cylinder arrays is also discussed in comparison with that of square cylinders.

中韩红绿颜色词文化意义对比及其教学启示

류밍위에 ( Liu Mingyue ),원진 ( Yuan Zhen ) 중국학연구회 2020 중국학연구 Vol.- No.93

作为汉两字文化圈的中韩国, 受古代儒道释文化的影响, 两国的传统 文化有很多相似。但在社会、语言、文化的发展中, 汉语和韩语里的特定 词语的意义出现了不少差异。1992年两国建交以来, 在韩国流行“汉风”, 中国也吹来了“韩流”。随之, 在两国便产生了第二外国语 ‘教育热’现象。在外国语教学中, 最具吸引人眼球的便是文化对比, 颜色词的文化意义也 成为教学的难点。因此本文选择韩汉教学中最常用红绿颜色词为研究对象, 比较两国红绿颜色词文化内涵的异同, 并探索红绿颜色词的教学意义。因此, 中韩红色颜色词有差异的是汉语中 ‘红’有嫉妒、成功与顺利、上升、忠义等意义, 而韩语 ‘红’则另有谎言的意义; 汉语绿色来形容低贱、背叛 以及着急, 而韩语中绿色是和平、年轻、公益、尖锐、权位等的象征, 这些 都是不同的文化所产生的。所以教学中以红绿颜色词为例可提高学生文学 的创作力与想象力, 两国红绿颜色词对比分析可了解中韩文化的差异, 并 能培养民族自信感。 As the cultural circle of Chinese characters, China and South Korea share many similarities in their traditional cultures influenced by Confucianism, Taoism and Buddhism. However, with the development of Society, language and culture, there are many differences in the meanings of specific words in Chinese and Korean. Since the establishment of diplomatic relations between the two nations in 1992, “Han style(汉风)” has become popular in South Korea, and “South Korean trend(韩流)” has also arrived in China. As a result, “education craze” of the second foreign language emerged in both countries. In foreign language teaching, cultural contrast is the most eye-catching, and the cultural meaning of color words has become a difficulty in teaching. Thus, choosing the most commonly used red and green colour words in the teaching of Korean and Chinese as the object of study, this paper compares the similarities and differences in cultural connotations of red and green colour words in two countries, and explores the educational significance of red and green colour words. Therefore, the difference between Chinese and Korean red words is that ‘red’ in Chinese has the meaning of jealousy, success, smooth, rising, loyalty, etc. while ‘red’ in Korean has the meaning of lies. Green in Chinese is used to describe lowliness, betrayal and worry, while green in Korean is a symbol of peace, youth, public welfare, sharpness, power and position, which are produced by different cultures. Hence, taking red and green colour word as an example in teaching can improve students’ imagination and comparative analysis of red and green colour words in the two countries can help understand the cultural differences between China and South Korea and cultivate the sense of national confidence.

남송시대 악록서원에서의 ‘교육의 사회적 책임’

류 밍위에(Liu Mingyue) 한국교육사상학회 (구 한국교육사상연구회) 2021 敎育思想硏究 Vol.35 No.1

이 연구의 목적은 남송시대 악록서원(嶽麓書院)에서 발견되는 교육의 사회적 책임 에 대해 탐색하는 데에 있다. 북송시대 선비들의 공부 목적은 과거시험에만 치중되어 있어서 학문자체 탐구의 중심이 아니었다. 남송시대는 혼란한 시기로 관학이 몰락하여서, 악록서원이 인재를 양성하는 사회적 책임의 역할을 담당하였다. 우선, 악록서원의 교육목적은 과거에 급제하는 것이 아닌 도 를 전파하고 백성을 구제하는 데에 있었다. 다음으로, 악록서원의 교육과정에서 주된 교과는 과거 한대(漢代)와 당대(唐代)에 해석된 유가 경전이며, 나중에 성리학의 실천적 학문으로 변모되었다. 이로써 학생들이 수신 , 제가 , 치국 , 평천하 라는 사회적 책임을 다하길 요청하였다. 또한, 국가의 난세에서 악록서원은 군사에 관한 교육을 중시하고 문무겸전한 선비들을 배양함으로써 사회적 책임을 다하였다. 마지막으로 악록서원은 제례(祭禮) 교육으로 전통문화계승의 사회적 책임을 다하였다. 요컨대, 전통교육이 몰락한 오늘날의 학교에서는 교육의 사회적 책임이 날로 실추되어 가고 있다. 특히 오늘날 학교에서의 제례에 관한 문화의 계승과 문무겸전한 인재를 양성하는 데에 남송시대의 악록서원이 좋은 모범이 될 수 있을 것이다. 그러므로 학습자들은 학이위기(學以爲己) 의 자기 이해의 교육에서 출발하여, 전통을 존중하고, 현실의 사회를 배려하고, 미래를 전망(展望)한다. The purpose of this study is to find out the educational social responsibility of Yuelu Academy(嶽麓書院) in the Southern Song Dynasty(南宋). In the Northern Song Dynasty, most intellectual used the imperial examination as their learning purpose, instead of focusing on learning. Howerver, in the chaotic period of the Southern Song Dynasty, the national school declined, and Yuelu Academy was in charged of the social responsibility of talent development. Firstly, the purpose of education had changed imperial examination to inherited tradition and provide relief to people(傳道濟民). Secondly, the educational curriculum was changed from the original Confucian classics in the Han(漢) and Tang(唐) Dynasties to Neo-Confucianism(性理學). Let students cultivate moral training and home management and order well their own states and govern the country. Thirdly, during the national crisis, Yuelu Academy was important to military education, training students with both civil and military skills, and allowing them to charge of social responsibilities. Finally, Yuelu Academy attached great importance to sacrificial rituals, carrying on the inheritance of traditional culture of the academy, and implemented the cultural responsibility of education. In short, when traditional education is declining, schools lack the education for social responsibility, especially the cultural inheritance in sacrifice and the cultivation of both civil and military talents. Therefore, learners should start from learning to improve yourself, and for promotion of self-understanding, respecting tradition, caring for society, and looking forward to the future.

Analysis of Academic Evaluation Indicators Based on Citation Quality

( Mingyue Zhang ),( Jin Shi ),( Jin Wang ),( Chang Liu ) 한국정보처리학회 2018 Journal of information processing systems Vol.14 No.4

The academic research performance is often quantitatively measured by means of using citation frequency. The citation frequency-based indicators, such as h-index and impact factor, are commonly used reflecting the citation quality to some extent. However, these frequency-based indicators are usually carried out based on the assumption that all citations are equal. This may lead to biased evaluations in that, the attributes of the citing objects and cited objects are significant. A high-accuracy evaluation method is needed. In this paper, we review various citation quality-based evaluation indicators, and categorize them considering the algorithms being applied. We discuss the pros and cons of these indicators, and compare them from four dimensions. The outcomes will be useful for our further research on distinguishing citation quality.

Research on Artificial Fish Swarm Algorithm with Cultural Evolution for Subcarrier Allocation

LIU Mingzhu,LI Xin,ZHANG Mingyu,LI Chang 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6

In the resource allocation process of multi-user OFDM system, in order to realize the purpose of maximizing the total transmission rate under constant power, a new subcarrier allocation algorithm has been proposed in this paper, which is to introduce cultural evolution method into the original artificial fish swarm algorithm. Because the population space in cultural algorithm framework has the advantage of guiding search process, the new algorithm can effectively overcome the defect of falling into local extreme which generally exists in the fish swarm algorithm in the resource allocation. At the same time, the proposed new algorithm also can make it easy to quantify the optimized goals and variable values. Simulation results show that the proposed artificial fish swarm algorithm with cultural evolution (CE-AFS) has been greatly improved the global search ability and convergence speed compared with the AFS algorithm and Shen algorithm.

Locating and identifying model-free structural nonlinearities and systems using incomplete measured structural responses

Liu, Lijun,Lei, Ying,He, Mingyu Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.2

Structural nonlinearity is a common phenomenon encountered in engineering structures under severe dynamic loading. It is necessary to localize and identify structural nonlinearities using structural dynamic measurements for damage detection and performance evaluation of structures. However, identification of nonlinear structural systems is a difficult task, especially when proper mathematical models for structural nonlinear behaviors are not available. In prior studies on nonparametric identification of nonlinear structures, the locations of structural nonlinearities are usually assumed known and all structural responses are measured. In this paper, an identification algorithm is proposed for locating and identifying model-free structural nonlinearities and systems using incomplete measurements of structural responses. First, equivalent linear structural systems are established and identified by the extended Kalman filter (EKF). The locations of structural nonlinearities are identified. Then, the model-free structural nonlinear restoring forces are approximated by power series polynomial models. The unscented Kalman filter (UKF) is utilized to identify structural nonlinear restoring forces and structural systems. Both numerical simulation examples and experimental test of a multi-story shear building with a MR damper are used to validate the proposed algorithm.