Development of Life Test Equipment with Real Time Monitoring System for Butterfly Valves

이기천,최병오,이영범,박종원,남태연,송근원 한국유체기계학회 2017 International journal of fluid machinery and syste Vol.10 No.1

Small valves including ball valves, gate valves and butterfly valves have been adopted in the fields of steam power generation, petrochemical industry, carriers, and oil tankers. Butterfly valves have normally been applied to fields where in narrow places installing the existing valves such as gate valves and ball valves have proven difficult due to the surrounding area and the heavier of these valves. Butterfly valves are used to control the mass flow of the piping system under low pressure by rotating the circular disk installed inside. The butterfly valve is benefitted by having simpler structure in which the flow is controlled by rotating the disc circular plate along the center axis, whereas the weight of the valve is light compared to the gate valve and ball valve above-mentioned, as there is no additional bracket supporting the valve body. The manufacturing company needs to acquire the performance and life test equipment, in the case of adopting the improving factors to detect leakage and damage on the seat of the valve disc. However, small companies, which are manufacturing the industrial valves, normally sell their products without the life test, which is the reliability test and environment test, because of financial and manpower problems. Furthermore, the failure mode analysis of the products failed in the field is likewise problematic as there is no system collecting the failure data on sites for analyzing the failures of valves. The analyzing and researching process is not arranged systematically because of the financial problem. Therefore this study firstly tried to obtain information about the failure data from the sites, analyzed the failure mode based on the field data collected from the customers, and then obtained field data using measuring equipment. Secondly, we designed and manufactured the performance and life test equipment which also have the real time monitoring system with the naked eye for the butterfly valves. The concept of this equipment can also be adopted by other valves, such as the ball valve, gate valve, and various others. It can be applied to variously sized valves, ranging from 25 mm to large sized valves exceeding 3000 mm. Finally, this study carries out the life test with square wave pressure, using performance and life test equipment. The performance found out that the failures from the real time monitoring system were good. The results of this study can be expanded to the other valves like ball valves, gate valves, and control valves to find out the failure mode using the real time monitoring system for durability and performance tests.

동아시아의 다원적 국제관계에 대한 인식과 교육 : <동아시아사> 교과서의 和蕃公主 서술에 대한 제언

이기천 서강대학교 인문과학연구소 2022 서강인문논총 Vol.- No.63

One of the notable changes in the 2015 Revised Curriculum in Korea is that Hefan princess is mentioned as a study factor in the theme, the diversification of international relations. It was evaluated positively that it can broaden perspective on international relations which is hitherto focused on investiture and tribute and then make it possible to look into diverse diplomatic methods. A survey was conducted among the students who completed revised curriculum in high school and are taking classes for history or history eduction major at three universities in Seoul, to find out how they perceive diverse international relations of East Asia. As a result, it shows that there is a marked contrast between Korean and Chinese students’ educational levels and perspectives on the definition, categories and roles of Hefan princess. This article compares and analyzes explanations of Hefan princess and textbook structures in history textbooks for secondary education in Korea and China. History textbooks in China provide that Hefan princess disseminated Chinese culture and it resulted in the formation of a united multi-ethnic country, whereas History of East Asia in Korea presents Hefan princess as well as investiture, tribute, and jimi system, etc. to explain various aspects of international relations. Its use of various elements such as chapter openers, images, maps, primary resources, and columns can enhance the effectiveness of education. However, it still needs some improvements such as adding historical records and research results in relation to an explanation of Bunian Tu and categories of Hefan princess. This article suggests how to explain benefits of international relations between Chinese dynasties and neighboring countries and to depict individual lives sacrificed by government’s decisions. 2015년 개정 교육과정의 눈에 띄는 변화 중 하나는 국제관계의 다원화라는 소주제에 和蕃公主라는 학습 요소가 명시되었다는 점이다. 그동안 조공・책봉에 집중되었던 국제관계에 대한 시각을 확장시켜, 다양한 외교 형식을 살펴본다는 점에서 긍정적으로 평가할 수 있다. 이러한 변화의 흐름 속에서 고등학교 교육과정을 이수한 현재의 대학생들에게 동아시아의 다원적 국제관계가 어떻게 인식되고 있는지를 살펴보기 위해, 서울 소재 주요 대학 3곳의 전공 수업에서 설문조사를 실시하였다. 그 결과 화번공주의 개념, 범주, 역할에 대한 한국인 학생과 중국인 학생의 인식과 교육 정도에 적지 않은 차이가 있음을 확인하였다. 그 원인에 대한 규명을 위해 본 연구에서는 한・중 양국의 고등학교 교과서의 구성과 화번공주 관련 서술을 비교・분석하였다. 중국의 교과서는 화번공주가 한족 문화를 전파함으로써 현재 중국의 다민족통일국가 형성에 기여했다는 논리를 구사하고 있었다. 반면, <동아시아사>는 조공, 책봉, 기미지배 등과 함께 화번공주를 제시하며, 다양한 국제관계의 면모를 설명하고 있다. 도입부, 그림, 지도, 읽기자료(사료), 칼럼 등 다양한 자료의 활용도 교육효과를 제고한다. 다만 내용 서술상 「步輦圖」에 대한 설명, 화번공주의 범주 등에 대해서는 사료와 연구성과를 반영하여 보완할 과제도 있다. 본고에서는 중국 왕조와 주변국 양자의 입장에서 국제관계의 효용성을 밝히고, 국가의 정책에 희생된 개인의 삶도 조명하는 교육방법을 제안하였다.

웃음여행

이기천 한국스포츠교육학회 2014 우리체육 Vol.- No.11

南朝~宋代 中國 승려가 바라본 ‘韓國系’ 求法僧

이기천 중국고중세사학회 2012 중국고중세사연구 Vol.28 No.-

本文是对佛教从中国传来并落定的过程中,结合华夷对韩国求法僧的认识,考察韩中佛教交流史的一个方面的论文。中国佛教至少到唐代为止始终没有摆脱‘蛮夷的宗教’这一排佛论者的批判,到了宋代以后站稳了脚跟,却没有实现自我发展,或者和性理学结合谋求哲学的转变。但是前期研究专注于量化的研究方法,或者存在单方面赋予对韩国僧侣活动的含义的倾向。为了克服‘自我评价’,笔者对梁《高僧传》到唐代编撰的《释门自镜录》中,中国方面的僧传进行分析的结果表明,到唐代为止,中国僧侣对于佛教的‘周边人’韩国僧侣的关心很少,或者持蔑视的态度。存在正传的书籍只有3部,所以虽然作为韩国人来说难以下出结论,但本文还是以先期研究中作为韩国僧侣记录的‘韩国血统’僧侣作为分析对象。对于韩国血统僧侣的中国行,有着边壤低水平的僧侣接受中国的教化变成达到高境地的佛教人的叙事结构。另外,中国僧侣坚持中国人单方面的華夷观。至少到唐代为止的文献中,从位于东亚佛教的“中心”的中国僧侣的立场来看,可以确认到中国僧侣认为韩国并不是很重要或者是比中国劣等的存在的意识。但是,从10世纪开始,中国僧侣看待韩国僧侣的姿态变低了。《祖堂集》中写道从中国僧侣口中说出“我们宗的法印回到了东国!”的话,或者像梵日的事例一样,不把韩国看做是教授的对象,而认为是本来的佛国土。而且,在接纳佛教初期,到中国学习佛法的韩国到了10世纪以后,成了将佛教全集逆向出口到中国的阶段。对于其背景,本论文认为是由于会昌废佛导致中国佛教的衰退,种派的形成和分化过程中出现的相承正统性问题导致的。但是,从1085年向入宋的义天发送的净源的答辞中可以确认,中国还存在正统的华夷观。

영화 베가번스의 전설

이기천 한국스포츠교육학회 2015 우리체육 Vol.- No.12

南朝~宋代 中國 승려가 바라본 ‘韓國系’ 求法僧

李基天 중국고중세사학회 2012 중국고중세사연구 Vol.28 No.-

A Study on the Separation of Ethylbenzene/p-Xylene Binary System with Zeolite Membrane

이기천,전유권,이진구,전소미,조용일,설용건 한국공업화학회 2012 한국공업화학회 연구논문 초록집 Vol.2012 No.1

建康 소그드인에서 北海 奚人으로 ― 魏博節度使 史憲誠 가문의 種族 인식과 혼란 배경 ―

이기천 동양사학회 2022 東洋史學硏究 Vol.158 No.-

This article reexamines the ethnicity of Shi Xiancheng, who served as Weibo military governor (jiedushi) from the second year of Changqing reign (822) to the third year of Dahe reign (829) and explains why Shi family’s perception towards ethnicity was changed. Considering the symbolic meaning of time, space and ethnicity that Shi family had, this research question was selected. This article also reviews the movements of Non-Han Chinese who were active in Weibo military province, a typical example of ‘the land of insurgency’ in ‘fanzhen domination period’, when lasted Five Dynasties and Ten Kingdoms period after An Lushan Rebellion (755-763) Ancestors of Shi Xiancheng are Sogdian who lived in the area of the First Turkic Empire as a form of Barbarian village. They emigrated to Tang when Turkic Empire collapsed, and Tang dynasty let them inward migration to Lingwu. Shi family chose Jiankang as their influential families of a prefecture. During Tian Ji’an’s incumbency as Weibo military governor (796-812), Shi Zhouluo, Shi Xiancheng, and so forth, rose to general officers in Weibo military province. It means the migration route of the Shi family was the First Turkic Empire [“Beifang”, “Shuoye”] → Lingwu → Weibo military province. However, Shi Xiancheng’s son Shi Xiaozhang perceived “Beihai” as a new influential family of a prefecture, impersonated Xi as their ethnicity, and considered surname Shi as surname Ashina, a famous surname of Northern nomadic tribe. These factors in the change of their perception towards ethnicity are complicated. Their consciousness of ancestors had been decreased during long-term habitation in China. For instance, King of Parthian was described as a descendant of Yellow Emperor (Xuan Yuan). The repugnance towards Sogodian was appeared after An Lushan Rebellion, so Sogdian themselves altered their native place and surname. A change to vaguely influential families of a prefecture sometimes made it difficult to distinguish their ethnicity. A shift in Shi family’s perception towards ethnicity reflects the change of Sogdian’s identities after loss of autonomy for their region in mid 7th century.

Jogging 및 Rope Skipping 운동이 여고생의 심폐 지구력에 미치는 영향

李基天 인하대학교 스포츠과학연구소 2000 論文集 Vol.12 No.-

This paper attempted to compare and analyze two groups-a comparison group and an experimental group, which are considered to improve the cardio-respiratory and aerobic exercise through the jogging and the rope-shipping. It also tried to find out how often and differently such exercises can affect the circulatory-respiratory abilities at the beginning or the finishing stage of a eight-week exercising period. For its convenience, twenty-four students from H Girls' High School were chosen. They were divided into two groups such as an experimental and a comparison group.(experimental group: eight students for jogging, and rope-skipping respectively. Comparison group : eight students). Using 'Tread Mill', the result was analyzed and some conclusions were made as follows ; 1.As for the variations concerning the aerobic cardio-respiratory, three groups showed expected difference(5%) as shown in table 4 statistically, when the average of pulse rate, maximum pulse rate, normal quantity of intaken oxygen and, maximum quantity of intaken oxygen, maximum carbon dioxide, and the hour of labor were sampled and analyzed, while the three groups showed little difference in the quantity of the breath ventilation, the quantity of the carbon dioxide, when they were relaxed. 2.As for the non-aerobic reverse value, the three groups showed the expected difference as shown in the table 5. But they showed no oxygen and the absolute value of breath-ventilation. 3.As for the pulse change at the time of restoration, there was a five-percent difference as shown in table 6, when the result of the estimate were sampled and analyzed directly after two minutes' exercise in jogging group-comparison group and rope-skipping group, comparison group, while there was little difference between the tow experimental groups, such as the jogging groups and rope-skipping groups. 4.As for the change of the lactic acid density concerning jogging and, rope-skipping, in comparison group, there appeared to be five percent difference as shown in table 7, when the average pulse rates among the three groups were estimated, whereas there was little difference between the jogging group and rope-skipping group directly before or after the given exercise.

Accelerated lifetime test using a moment bar for a base frame of an aerial-work-platform vehicle

이기천,이영범,최병오,최종식,신영락,맹주원 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

The demand for high aerial work platforms has increased gradually. A safe and lightweight structure is necessary to cut short increasing costs of existing materials. To serve the purpose a base frame structure made of concrete and steel is developed for such a platform. However, it was difficult to replicate field conditions when testing the durability and safety of structure. In this study, the failure analysis of the base frame in the field operating condition for the reappearance and accelerated life test was performed. Also, the equations describing the characteristics of the aerial work platform for force and moment due to the weight and the wind at the top of the equipment were introduced and proved. Failure reappearance mechanism using the moment bar was applied for the force and moment simultaneously to the lower frame which reproduced the failure modes with the real size frame. Also, accelerated life test time was induced by using no failure life test time, the shape parameter, and acceleration factor which should be considered with the field operating conditions. The performance test was conducted after attaching the strain gauges at the weak points of the lower frame to prove the effectiveness of the moment bar. The strain values taken from the finite element analysis had the consistent results with the experimental data. It means that the moment bar can be applied to the other aerial work platforms.