• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.87-89
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• 2005

In this paper, we analyzed that characteristics of flux-lock type superconducting fault current limiter (SFCL) using the third winding to fault current limiting. The flux-lock type SFCL using the third winding consists of the first and seconding windings which are wound in parallel each other a iron core. Also it connected inductively the third winding connected resistance of series. Because of the hysteresis according to the increased voltage, the distortion of current in the flux-lock type SFCL occurs. It is a disadvantage to increase the capacity of SFCL. We conformed that the third winding of the flux-lock type SFCL prevented the distortion of current. Also, the third winding did not affect the initial fault current of the flux-lock type SFCL.

• Journal of Korean Dental Science
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• 제4권2호
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• pp.85-91
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• 2011

Some treatment methods have been proposed for patients with chronic closed lock of temporomandibular joint. We report a conservative treatment for patients who had chronic closed lock of temporomandibular joint and who did not want surgical treatment. Two patients who had been treated in the Template clinic, Soonchunhyang University Bucheon Hospital, are the subjects of this report. The subjects had chronic closed lock symptom for over 3 months after an onset of locking; conventional therapies had no effect. The subjects were treated by making them wear a Template appliance while sleeping and exercise for 10 hours a day. After periodic follow-up, significant improvement was observed for Template treatment in terms of the maximal mouth opening range. When conventional therapy is expected to be ineffective, The Template appliance can be used as conservative treatment for temporomandibular disorders patients with chronic closed lock of temporomandibular joint.

• 반도체디스플레이기술학회지
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• 제13권4호
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• pp.77-81
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• 2014

There have been developed in authentication systems for information using biometric information approaches such as fingerprint, face, and iris. In general, a door-lock system is operated by touching keypads, which remains fingerprints on the keypads. Such door-lock systems do not protect personal information from others due to the exposure of fingerprints to keypads. In this paper, we propose the new door-lock system that does not leave fingerprints on the keypads. Without touching keypad the system works because the system accepts authentication information by using illuminance sensor and LED. The experiment shows that the implemented door-lock system works well under any circumstance.

• International Journal of Aeronautical and Space Sciences
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• 제13권1호
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• pp.27-33
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• 2012

The relationship between the excitation frequency and the vortex shedding frequency is analyzed during the oscillation of the circular cylinder. Two-dimension unsteady Navier-Stoke's equation is calculated by using the Optimized High Order Compact (OHOC) scheme. The flow condition is Mach number 0.3 and Reynold's number 1000. From the results acquired by calculation, it can be inferred that, when the excitation frequency is near the vortex shedding frequency at the fixed cylinder wake, the oscillation frequency of lift and drag coefficients appears to lock-on. The lock-on refers to a phenomenon in which the aerodynamic coefficient appears as one primary oscillation frequency through excitation and its amplitude is amplified. In the non-lock-on zone, the excitation frequency is not in the lock-on mode anymore and beat is formed in which two or more primary oscillation frequencies of the aerodynamic coefficient are mixed together.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.493-495
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• 2006

The hysteresis characteristics of flux-lock reactor, which is an essential component of flux-lock type superconducting fault current limiter (SFCL), was investigated. The hysteresis loss of iron core in flux-lock type SFCL does not happen due to its winding's structure especially in the normal state. From the equivalent circuit for the flux-lock type SFCL and the fault current limiting experiments, the hysteresis curves could be drawn. Through the hysteresis curves together with the fault current level due to the inductance ratio for the 1st and 2nd windings, the increase of the number of turns in the 2nd winding of the flux-lock type SFCL had a role to prevent the iron core from saturation.

• Current Optics and Photonics
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• 제7권6호
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• pp.683-691
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• 2023

A typical terahertz time-domain spectroscopy system requires large, expensive, and heavy hardware such as a lock-in amplifier and a function generator. In this study, we replaced the lock-in amplifier and the function generator with a single sound card built into a typical desktop computer to significantly reduce the system size, weight, and cost. The sound card serves two purposes: 1 kHz chopping signal generation and raw data acquisition. A unique software lock-in (Python coding program to eliminate noise from raw data) method was developed and successfully extracted THz time-domain signals with a signal-to-noise ratio of ~40,000 (the intensity ratio between the peak and average noise levels). The built-in sound card with the software lock-in method exhibited sufficiently good performance compared with the hardware-based method.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.104-109
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• 2018

일반적으로 변속기 전체에 대한 내구시험을 통하여 파킹 락 기어의 내구성을 평가한다. 파킹 락 기어 부품 하나의 내구시험에 대한 시험 기준은 부재한 상황이다. 따라서 본 연구에서는 파킹 락 기어의 내구시험 기준을 자체적으로 설정하여, 내구 성능시험을 수행하였다. 파킹 락 기어의 항복응력을 구하기 위해 정적 파단 시험을 수행하였고, 항복응력의 60%를 내구시험 조건으로 설정하였다. 설정된 시험조건으로 100만회의 반복내구 성능시험을 수행하였다. 또한, 내구 성능시험을 수행하기 위하여, 전용 지그를 제작하였다. 제작된 지그가 정적 파단시험에서 파손되어, 파손된 지그에 대한 유한요소해석을 수행하고 설계를 변경하였다. 수정한 지그를 제작하여 자체적으로 설정한 시험기준으로 내구 성능시험을 수행한 결과, 파킹 락 기어는 본 조건에 충족하였다. 본 연구에서 수행된 시험과 해석을 통하여 파킹 락 기어의 성능 및 내구 한계에 대한 기초 데이터를 확보하였고, 이러한 기초 데이터는 파킹 락 기어의 설계와 개발에 중요한 기초 자료로 활용될 것으로 사료된다.

• 한국기계가공학회지
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• 제18권9호
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• pp.44-51
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• 2019

Three types of samples with defects were measured by lock-in med-IR (infrared) thermography with various lock-in frequencies for different materials. The lock-in method can be used to detect defects when an external energy source is applied to the object, the non-uniformity of the incident thermal energy distribution is eliminated, and the camera's measurement cycle is synchronized with the load cycle of the incident energy source. For inspecting samples with defects, results of thermal images are analyzed when three types of materials, i.e., SM45C, STS316L, and AL6061 are tested and three lock-in frequencies, i.e., 0.08, 0.1, and 0.12 Hz are applied. In this study, the optimal lock-in frequencies were determined by comparing the results of each material and lock-in frequency measured using the mid-IR camera.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.1865-1870
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• 2014

토크 컨버터는 록업 클러치에 의해 엔진으로부터 변속기로 원활하게 동력을 전송하는 데 사용되는 복잡한 터보기계부품이며 유체 클러치 장치와 록업 클러치 장치로 구성된다. 고정 플레이트와 구동 판은 록업 클러치의 일부이며 록업 클러치는 효율과 연료 소비의 개선과 직접적인 관계가 있다. 본 논문에서는, 미케니컬 스토퍼가 장착되어 있는 리테이닝 플레이트의 응력 분포 특성을 분석하였으며. 미케니컬 스토퍼의 형태는 로크 업 클러치의 응력 분포에 영향을 미치는 것을 파악하였다.

• 한국전기전자재료학회논문지
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• 제24권2호
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• pp.136-140
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• 2011

The fault current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) using a transformer winding were investigated. The suggested flux-lock type SFCL consists of two parallel connected coils on an iron core and the transformer winding connected in series with one of two coils. In this SFCL, the high-TC superconducting (HTSC) element was connected with the secondary side of the transformer. The short-circuit experimental devices to analyze the fault current limiting characteristics of the flux-lock type SFCL using the transformer winding were constructed. Through the short-circuit tests, the flux-lock type SFCL using transformer winding was shown to perform more effective fault current limiting operation compared to the previous flux-lock type SFCL without the transformer winding from the viewpoint of the quench occurrence and the recovery time of the HTSC element.