광섬유 Sagnac 간섭계를 이용한 초음파의 비접촉식 감지

이정주,장태성,이승석,김영길,권일범,이왕주,Lee, Jeong-Ju,Jang, Tae-Seong,Lee, Seung-Seok,Kim, Yeong-Gil,Gwon, Il-Beom,Lee, Wang-Ju 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.9

This paper describes a fiber optic sensor suitable for non-contact detection of ultrasonic waves. This sensor is based on a fiber optic Sagnac interferometer. Quadrature phase bias between two interfering laser beams in Sagnac loop is introduced by a polarization controller. A stable quadrature phase bias can be confirmed by observing the interferometer output versus phase bias. This method eliminates a digital signal processing for detection of ultrasonic waves using Sagnac interferometer. Interference intensity is affected by the frequency of ultrasonic waves and the time delay of Sagnac loop. Collimator is attached to the end of the probing fiber to focus the light beam onto the specimen surface and to collect the reflected light back into the fiber probe. Ultrasonic waves produced by conventional ultrasonic transducers are detected. This fiber optic sensor based on Sagnac interferometer is very effective for detection of small displacement with high frequency such as ultrasonic waves used in conventional non-destructive testing.

세제 농도에 따른 세척력과 세제성분의 잔류

이정주,김유겸,Lee, Jung-Ju,Kim, You-Kyum 한국섬유공학회 2011 한국섬유공학회지 Vol.48 No.2

Selected standard methods for washing machines: agitating type; horizontal drum type. Market detergents: standard powder detergent; powder detergent; liquid detergents. Standard soiled clothes composed of five types, including the various contaminants from the actual life of soiled clothes, respectively. When washing with the standard course for a washing machine and using the standard, recommended amount of detergent product, the detergency for the agitating-type washing machine and standard soiled clothes increased by approximately 25%, on average, compared to the case of -30% use, and increased by 2% compared to the case of +60% use, respectively. When the horizontal drum-type washing machine was used, detergency increased by approximately 28%, on average, compared to -30% use, and increased by 12% compared to +100% case. Accordingly, the detergency when using the standard amount of detergent increased by approximately 27% on average, and increased by approximately 7% compared to the cases of +60%~+100% use. Moreover, the residue of the detergent components was extremely small, but proportional nonetheless to detergent concentration.

자동차 브레이크 마찰재용 비침상형 육티탄산칼륨의 합성 연구

이정주,이나리,피재환,김종영,김정주,Lee, Jung Ju,Lee, Na-Ri,Pee, Jae-Hwan,Kim, Jong-Young,Kim, Jeong-Joo 한국재료학회 2017 한국재료학회지 Vol.27 No.3

We synthesized potassium hexatitanate, ($K_2Ti_6O_{13}$, PT6), with a non-fibrous shape, by acid leaching and subsequent thermal treatment of potassium tetratitanate ($K_2Ti_4O_9$, PT4), with layered crystal structure. By controlling nucleation and growth of PT4 crystals, we obtained splinter-type crystals of PT6 with increased width and reduced thickness. The optimal holding temperature for the layered PT4 was found to be ${\sim}920^{\circ}C$. The length and width of the PT4 crystals were increased when the nucleation and growth time were increased. After a proton exchange reaction using aqueous 0.3 M HCl solution, and subsequent heat treatment at $850^{\circ}C$, the PT4 crystal transformed into splinter-type PT6 crystals. The frictional characteristics of the friction materials show that as the particle size of PT6 increases, the coefficient of friction (COF) and wear amounts of both the friction materials and counter disc increase.

대학에 대한 새로운 사회의 요구

이정주,Lee, Jeong-Ju 한국대학교육협의회 2004 大學敎育 Vol.127 No.-

우리의 가장 좋은 자원은 인적자원이다. 대학이 이 풍부한 인적자원을 지식근로자로 육성할 때 우리는 세계시장에서 다시 경쟁력을 회복할 수 있게 될 것이다. 청년실업문제는 노동정책의 문제가 아니라 대학교육 개혁의 문제로 인식되어야 하는 것이다.

센서네트워크 어플리케이션을 위한 네트워크 프레임워크와 통합시뮬레이터 간의 인터페이스 구현 및 설계

이정주,곽동은,서민석,박현주,Lee, Jeong-Joo,Koak, Dong-Eun,Seo, Min-Suk,Park, Hyun-Ju 한국정보통신학회 2013 한국정보통신학회논문지 Vol.17 No.2

신뢰성 있는 소프트웨어 개발을 위해서 가장 중요한 단계 중의 하나가 소프트웨어 테스트이다. 최근에 점진적이고 반복적인 소프트웨어 개발 방법론이 각광을 받으면서, 소프트웨어의 작은 변경에 따른 회귀 테스트의 중요성이 점점 커지고 있다. 또한 센서네트워크와 같은 다수의 노드 환경에서 동작하는 소프트웨어를 검증하기 위한 시뮬레이터 환경이 필요하다. 본 논문에서는 네트워크 프레임워크와 통합시뮬레이터 간의 인터페이스 모듈을 구현하여, 네트워크 프레임워크로 구현한 센서네트워크 어플리케이션을 다양한 가상의 환경에서 단위테스트하기 위한 환경을 제공한다. For the development of reliable software, Software testing is the most important. Recently small changes of the software according to the importance of regression testing is growing. To verify Application of a large number of nodes, Network simulator environment is required. This paper proposed interface module between network framework for sensor network application and co-simulator to unit test sensor network application. To conclude, developer can focus on sensor network application implementation only, so the improved integrated simulator contributes to increase development productivity.

소비자 구매특성에 따른 중저가 캐쥬얼 상표 이미지 지각의 차이

이정주,진병호 ( Jung Ju Lee,Byoung Ho Jin ) 대한가정학회 1996 Family and Environment Research Vol.34 No.3

이차전지(二次電池) 제조공정(製造工程)스크랩으로부터 고효율(高效率) 親環境(친환경) 코발트(Co)와 리튬(Li)의 회수(回收)에 관(關)한 연구(硏究)

이정주,정진도,Lee, Jeong-Joo,Chung, Jin-Do 한국자원리싸이클링학회 2010 資源 리싸이클링 Vol.19 No.6

리튬이차전지 양극스크랩으로부터 코발트와 리튬을 회수하기위해 물리적 전처리, 침출, 용매추출 및 회수실험을 행하였다. 실험재료로 제조공정에서 발생되는 코발트계 양극스크랩을 사용하여 단위공정별 최적조건을 구하였다. 물리적전처리 최적조건은 온도 $500{\sim}550^{\circ}C$, 파쇄날 회전속도 1000rpm이었으며, 침출 최적조건은 300rpm, 2M $H_2SO_4$, 2.5M $H_2O_2$, $95^{\circ}C$이었다. D2EHPA(bis(2-ethylhexyl) phosphoric acid) 와 PC88A를 각각 알루미늄과 코발트의 추출제로 사용하여 분리.정제하였으며, 코발트는 염기성시약을 사용하여 $Co(OH)_2$로, 리튬은 탄산나트륨 및 LiOH를 사용하여 탄산리튬($LiCO_3$)으로 회수하였다. $Co(OH)_2$는 열처리를 하여 삼산화코발트($Co_3O_4$)로 만들고 분쇄기를 사용하여 10 ${\mu}m$정도의 입자를 만들었다. 최적조건에서 코발트와 리튬 회수율은 99%이상, 리튬회수율은 99%이상이었으며, 삼산화코발트의 순도는 99.98%이상이었다. A study on the recovery of cobalt and lithium from Lithium Ion Battery(LIB) scraps has been carried out by a physical treatment - leaching - solvent extraction process. The cathode scraps of LIB in production were used as a material of this experiment. The best condition for recovering cobalt from the anode scraps was acquired in each process. The cathode scraps are dissolved in 2M sulfuric acid solution with hydrogen peroxide at $95^{\circ}C$, 700 rpm. The cobalt is concentrated from the leaching solution by means of a solvent extraction circuit with bis(2-ethylhexyl) phosphoric acid(D2EHPA) and PC88A in kerosene, and then cobalt and lithium are recovered as cobalt hydroxide and lithium carbonate by precipitation technology. The purity of cobalt oxide powder was over 99.98% and the average particle size after milling was about 10 lim. The over all recoveries are over 95% for cobalt and lithium. The pilot test of mechanical separation was carried out for the recovery of cobalt from the scraps. The $Co_3O_4$ powder was made by the heat treatment of $Co(OH)_2$ and the average particle size was about 10 ${\mu}m$ after grinding. The recovery was over 99% for cobalt and lithium each other and the purity of cobalt oxide was over 99.98%.

On the Frequency and Distribution of the Acatalasemia and Hypocatalasemia in Korean Population

이정주,Lee, Chung Choo The Korean Society for Integrative Biology 1975 동물학회지 Vol.18 No.3

The purposes of this study were to investigate the frequencies of acatalasemia and hypocatalasemia in Korean population to compare with those of Japanese, Chinese and chiefly Taiwan population. The results obtained were as followings; 1. In south area of Korea, Jeonju, Gwangju, Busan and Daegu, a total of 3,629 individuals were tested. No acatalasemia was found but 0.26% of hypocatalasemia in Jeonju, 0% in Gwangju, 0.21% in Busan and 0.06% in Daegu were found. 2. The frequency of hypocatalasemia in south area of Korea was found to be lower than in middle area. 3. The frequency of hypocatalasemia in this study was similar to that of Chinese(in Taiwan) and higher than that of Japanese. 4. The reason of the geographical differences in the freqency of the hypocatalasemia was considered to be due to the natural selection. And the reason of the higher frequency of Korean population living in Japan was considered that originally the frequency of Korean population is higher, and the maintenace of this higher degree is obliged to the assortative mating beteen them.

정장열처리 나일론 6 부분배향사의 열적 성질 및 물성

이정주,조길수,김갑진,Lee, Jeong-Ju,Jo, Gil-Su,Kim, Gap-Jin 한국섬유공학회 1987 한국섬유공학회지 Vol.24 No.5

This study was carried out to investigate the thermal and physical properties of nylon 6 POY which was taut-annealed under various conditions. On the basis of the DSC curves, it was found that the origin of the double melting peaks of nylon 6 POY was due to the coexistence of crystals with different thermal properties. Among the scanning rates of 5$^{\circ}C$/min, 20$^{\circ}C$/min and 40$^{\circ}C$/min, the last was best to study the effect of annealing on the melting behavior of nylon 6 POY because it was able to eliminate or minimize the programmed heating effect during DSC analysis. Crystallinity and birefringence of annealed specimens increased as the treatment temperature and time increased. Tenacity at break increased as the temperature increased up to 180$^{\circ}C$, but decreased as the time increased. Elongation at break decreased as the annealing temperature and time increased.

수재해 정보관리 및 서비스를 위한 공간, 비공간 정보 자료 개념 설계

이정주,김동영,정영훈,황의호,채효석,Lee, Jeong-Ju,Kim, Dong-Young,Jung, Young-Hun,Hwang, Eui-Ho,Chae, Hyo-Sok 한국농공학회 2016 한국농공학회논문집 Vol.58 No.2

This study conducted a basic design of system and interface which provide both of spatial and non-spatial data for water hazard information management. This helps to decide directions of the future integrated water hazard information platform and possible technical examinations of the web-based system for the realization of the prototype. For user friendly system, this study did a survey to investigate the data format, service environment, image processing level and visualization type that users prefer. Also, authorization range was set up by type of the user group. In the water hazard information platform, the data and analysis algorithm were classified by the fields. Furthermore, the platform was consisted with six block systems according to the function and the interface and designed to flexibly mount or modify the additional functions. For a basic design of the data exchange method and protocols, a prototype was constructed by using the spatial information web service technology. The portal service system to visualize and provide spatial data was designed by the WMS/WFS type of OGC standard interface and the FTP/HTTP interface type through open source GIS software for server environment.