증사 / 희년전도대활동

이정율 기독교대한성결교회 활천사 1957 활천 Vol.286 No.-

Multiplexed Hard-Polymer-Clad Fiber Temperature Sensor Using An Optical Time-Domain Reflectometer

이정율,김형철 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.1

Optical fiber temperature sensing systems have incomparable advantages over traditional electrical-cable-based monitoring systems. However, the fiber optic interrogators and sensors have often been rejected as a temperature monitoring technology in real-world industrial applications because of high cost and over-specification. This study proposes a multiplexed fiber optic temperature monitoring sensor system using an economical Optical Time-Domain Reflectometer (OTDR) and Hard-Polymer- Clad Fiber (HPCF). HPCF is a special optical fiber in which a hard polymer cladding made of fluoroacrylate acts as a protective coating for an inner silica core. An OTDR is an optical loss measurement system that provides optical loss and event distance measurement in real time. A temperature sensor array with the five sensor nodes at 10-m interval was economically and quickly made by locally stripping HPCF clad through photo-thermal and photo-chemical processes using a continuous/pulse hybrid-mode laser. The exposed cores created backscattering signals in the OTDR attenuation trace. It was demonstrated that the backscattering peaks were independently sensitive to temperature variation. Since the 1.5-mm-long exposed core showed a 5-m-wide backscattering peak, the OTDR with a spatial resolution of 40 mm allows for making a sensor node at every 5 m for independent multiplexing. The performance of the sensor node included an operating range of up to 120oC, a resolution of 0.59 oC, and a temperature sensitivity of -0.00967 dB/oC. Temperature monitoring errors in the environment tests stood at 0.76 oC and 0.36 oC under the temperature variation of the unstrapped fiber region and the vibration of the sensor node. The small sensitivities to the environment and the economic feasibility of the highly multiplexed HPCF temperature monitoring sensor system will be important advantages for use as system-integrated temperature sensors.

엘리트 운동선수의 코치-선수관계와 기본심리적욕구가 스포츠전념에 미치는 영향

이정율(Lee, Jung-Yul),이동현(Lee, Dong-Hyun) 한국사회체육학회 2021 한국사회체육학회지 Vol.- No.86

Purpose: The purpose of this study is to verify the effect of coaching leadership and basic psychological needs on the sports commitment of elite athletes. Method: The data were collected for elite athletes including high schools, universities, and elite athletes registered with the Korea Sports Council. Excluding 29 copies, a total of 271 copies were analyzed. Results: Firstly, hierarchical regression analysis phase 1 showed that the familiarity and completeness of the coach-player relationship had a static effect on cognitive precepts. The commitment had no significant effect on cognitive precepts. In addition, the commitment and familiarity of the coach-player relationship have been shown to have a static effect on behavioral commitment and complementary had not significantly affected behavioral commitment. Secondly, in the second phase of hierarchical regression analysis, the familiarity and completeness of coach-player relationships were shown to have a static effect on cognitivism, and the relationship of basic psychological needs had an impact on cognitivism, and the relationship of basic psychological needs had an impact on cognitivism and behavioural of sports commitment. Conclusion: It has confirmed that coach-player relationships and basic psychological needs are important factors in sports commitment, and it will be an opportunity to promote research according to the characteristics of players and leaders in the sports field.

엘리트 운동선수의 스트레스와 대처유연성 및 운동탈진의 관계

이정율(Lee, Jung-Yul),이지항(Lee, Ji-Hang),이동현(Lee, Dong-Hyun) 한국사회체육학회 2023 한국사회체육학회지 Vol.- No.93

Purpose: The purpose of this study is to verify the effect of stressn ad coping flexibility on burnout in elite athletes. Method: To achieve this purpose, data were collected from elite athletes including those from high schools, universities, businesses, and professional athletes registered with the Korea Sports Council. A total of 400 responses were analyzed. The collected data were subjected to hierarchical regression analysis using IBM SPSS 25.0, and the following results were derived. Results: In the first stage of hierarchical regression analysis, it was found that personal time constraints and career-related stress had a positive effect on the perceived loss of exercise value. However, leadership dissatisfaction and function/game content did not have a signiicfant effect. Additionally, complaints about leadership, function/game content, and personal time constrainst of stress were found to have a positive effect on psychological and physical exhaustion. However, carere concerns did not have a significant effect on psychological and physical exhaustion. Finally, it was found that the function/game content of stress and career concerns positively influenced the lack of achievement, while leadership dissatisfaction had a negative effect. In the second stage of hierarchical regressio nanalysis, it was found that the flexibility of coping behaviors in response to personal time constraints, carer concerns, and overall coping flexibility had a significant impact on the likelihood of receiving awards for the athletes. Additionally, perceived coping resources were found to have a negative effect. Moreover, personal time constraints of stress, function/game content, leadership dissatisfaction, and coping flexibility were found to have a positive effect on psychological and physical exhaustion. Finally, it was discovered that career concerns, function/game content, and coping behavior flexibility had a significant impact on the lack of achievement, while leadership and perceived coping flexibility had a negative impact on stress. Conclusion: In summary, the results of this study confirm that stress an dcoping flexibility are important factors in burnout among elite athletics. These findings provide an opportunity to promote further research aimed at preventing exhaustion among athletes in the sports field.

Application of the ultrasonic propagation imaging system to an immersed metallic structure with a crack under a randomly oscillating water surface

박재윤,이정율 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9

Ultrasound is widely used and studied to satisfy the increased demands of the Non-destructive evaluation (NDE) and testing of underwater structures. However, because of the large size and mass of underwater structures, such as submarines, ship hulls, or nuclear reactor pipe lines, it is difficult to inspect the structures during operation. This underwater NDE technology is challenging but could be highly beneficial because the time and cost of maintenance will be effectively reduced. We propose an NDE method for immersed structures using an ultrasonic propagation imaging system with a piezoelectric sensor. The underwater sensing capability of a piezoelectric sensor is experimentally demonstrated using an aluminum plate specimen. A piezoelectric sensor can compensate for the decreased signal amplitudes due to leaky waves that are generated on interfaces between structures and water, since water transmits signals better than air. Additionally, a piezoelectric sensor can be applied even if the water surface is oscillating. Using these properties, the laser induced guided Ultrasonic propagation imager (UPI) inspected a T-shaped steel structure with a 2-mm crack on the weld zone. The inspection was implemented in three cases: a specimen without water, a specimen immersed in water and a specimen immersed in water with a randomly oscillating surface. The crack was visualized and measured using the ultrasonic wave propagation imaging algorithm, the adjacent wave subtraction algorithm, and the variable time window amplitude mapping algorithm. In the case with a randomly oscillating water surface, the laser pulse was refracted randomly based on Snell’s law. This phenomenon may cause degradation of the inspecting results. However, a repeated scanning process and outlier elimination led to an improved signal-to-noise ratio such that it was able to detect the crack. These results demonstrate the possibility to apply the laser UPI to submerged structures even if the water surface is randomly oscillating.

차세대고속철도 차량시스템 (HEMU-430X) 소개

민평오,이정율 대한전기학회 2013 전기의 세계 Vol.62 No.6

무선 PBX의 기술추세

한진호,이정율 대한전자공학회 1994 전자공학회지 Vol.21 No.7

방적사의 단주기 불균제도에 관한 연구(제1보) -프런트 톱 로울러의 편심이 단주기불균제도에 미치는 영향-

유운영,이정율 한국섬유공학회 1976 한국섬유공학회지 Vol.13 No.2

Effect of the eccentric front top roller on the short term irregularity of three spun yarns, carded 30's combed 83's and polyester/ cotton blended 45's was studied, and the results of it were as the followings; 1. Effect of the eccentricity of front top roller on the irregularity of the spun yarn was significant and the irregularity produced was linearly increased with the level of eccentricity. 2. Maximum allowable eccentricity of front top roller for the tested yarns should be less than 2/100mm to avoid irregularity caused from the eccentricity. 3. Added irregularity (CVE) produced only from the eccentricity was expressed with the following empirical equations; CD30 : CVE=105(D-1)α·e/d-0.3 CD30 : CVE=73(D-1)α·e/d+1.8 P/C45 : CVE=63(D-1)α·e/d+2.0 where D : draft ratio e : eccentricity (1/100mm) d : diameter of top roller (mm) d' : diameter of bottom roller (mm) α : 2d'/d+d' 4. Irrequalarity caused from the eccentric front top roller had periodicity and most of their length of period were the same as the circumference of the roller and some of them were the half of it. 5. Single strand strength of spun yarn was decreased, as the eccentricity was increased and the rate of it had the maximum value on the carded yarn 30's.

모바일 펄스-에코 초음파 전파 영상화 장치를 사용한 T-50 고등훈련기 수평 안정판 현장 비파괴 평가

홍승찬,이정율,박종운 한국비파괴검사학회 2019 한국비파괴검사학회지 Vol.39 No.5

Defects and damages, such as disbond and delamination, mainly occur in composite structures, which are increasingly used in aircraft structures, and their detection is difficult. A mobile pulse-echo ultrasonic propatation imager(PE UPI) is a laser ultrasonic nondestructive inspection tool used as an in-situ nondestructive evaluation tool. The potential of mobile PE UPIs has been confirmed through a certification test of non-destructive standard specimens and F-16 Lockheed Martin standard specimens from the Korea Air Force. In this study, a mobile PE UPI was applied to the horizontal stabilizer of a T-50 advanced trainer as an in-situ non-destructive evaluation tool, and the field applicability of mobile PE UPI was proved by comparing inspection results with the conventional A-scan ultrasonic testing technique. 항공기 구조에서 사용이 증가되고 있는 복합재에서 접착 분리와 층간 분리와 같은 결함 및 손상이 주로 발생되고 있으며 탐지의 어려움이 있다. 최근에는 레이저 발생기를 사용하여 구조 표면에 초음파를 사용한 새로운 기술 레이저 비파괴 기법이 연구되고 있다. Mobile PE UPI는 현장 비파괴 평가용으로 개발된 레이저 초음파 비파괴 검사 장치로 한국 공군으로부터 비파괴 표준 시편과 F-16 록히드 마틴 표준 시편의 인증 테스트를 통과해 현장 비파괴 평가 장치로써 가능성을 확인한 바 있다. 본 논문에서는 Mobile PE UPI를 사용하여 T-50 고등훈련기 수평 안정판 현장 비파괴 평가 장치로써 적용하고 기존 A-scan 초음파 탐상 기법과 비교를 통해 검증하고 현장 적용성을 입증하였다.

폐기콘크리트를 활용한 재생골재의 각종 물성에 관한 실험적 연구

김규용,이정율,박유신,임정수,김무한 한국폐기물자원순환학회 1998 한국폐기물자원순환학회지 Vol.15 No.3