예산성결교회 / 예산성결교회당신축기

이창제 기독교대한성결교회 활천사 1934 활천 Vol.140 No.-

PIV를 이용한 수중로봇용 림 추진기 후류 특성에 관한 연구

이창제,허민아,조경래,김형호 한국수산해양기술학회 2022 수산해양기술연구 Vol.58 No.1

본 연구는 수중 로봇용 림 추진기의 기초연구이다. 림 추진기는 림의 회전운동 등으로 인해 프로펠러 추진 기와는 다른 유동특성을 가진다. 따라서, 림 추진기의 고유 유동 특성을 반영하여 설계할 필요가 있다. 본 연구 에서는 단면이 대칭인 NAC 0012를 기반으로 날개를 설계하였고, PIV를 이용하여 후류 특성을 파악하였다. 낮은 전진비에서는 model 2가 더 높은 속도를 보였으나, 높은 전진비에서는 model 1이 높은 속도를 보였다. 축방 향 속도는 model 1의 경우 전진비 전체에 걸쳐 대칭인 형태를 보였으나, model 2는 낮은 전진비(0.2, 0.4)에서 비대칭으로 나타났다. 이것은 자유 수면과 바닥의 영향이 후류 구조에 영향을 미치는 것으로 판단된다. 림 추진 기 내부에서는 덕트와 가까운 영역에서 와도가 높았으 나, 덕트의 영향으로 인해 후류 방향의 와도가 상당히 소멸되었다. 그러나 덕트 형상은 최적화 될 필요가 있다. 본 연구를 통해 소형 수중 로봇에 사용되는 림 추진기의 설계에 필요한 후류 특성의 정보를 제공하였다. 각 부하 조건에서 후류 특성을 통해 수중로봇이 효율적, 안정적 으로 구동될 수 있는 조건을 확인하였다. 향후 설계조건 과 운영조건을 다양화하여 연구를 진행하고자 한다.

Study on Monitoring of Plasma Emission Signal in Lap Welding of Zn Coated Steel Sheet Using CO2 Laser

이창제,김종도,김유찬 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

In this study, induced plasma that is created during the CO2 laser lap welding of 6-mm-thick Zn coated steel for shipbuilding weremeasured through photo-diode and microphone. Then, we compared and analyzed the RMS value of plasma emission signal andspatter generation amount as a function of lap clearances with Zn coated thickness. The results indicated that as RMS valuesincreased depending on the amount of Zn vaporization, and RMS also changed abruptly when defects occurred depending on lap jointconditions. Also, as a result of obtaining FFT value of raw signal by welding conditions, the obtained frequency signal was about30 Hz at coating thickness 15 μm and about 50 Hz at coating thickness 30 μm in light signal, and in acoustic signal, peak valueappeared at about 1 kHz. In addition, it was found that when the frequency value was set as the bandwidth of bandpass-filter, andthe RMS values which were obtained after filtering raw signals were matched to weld bead. Thus we have considered that the signalsand defects were very closely related.

API강재의 파이버레이저 용접시 유기되는 플라즈마의 방사특성 (II) -용접조건과 방사신호의 관련성-

이창제,김종도,김유찬,Lee, Chang-Je,Kim, Jong-Do,Kim, Yu-Chan 대한용접접합학회 2012 대한용접·접합학회지 Vol.30 No.4

Laser welding by fiber laser accompanied by a lot of spatter and humping bead. This is because the deep and narrow keyhole usually form due to high beam quality. So the weld bead is formed defects, because the plasma jet with a high vapor pressure make the molten pool on keyhole wall scattered. For such a reason, unstable behavior of keyhole is difficult to monitor laser welding by using the laser induced plasma. Mostly, fiber laser welding of thick plates most be influenced by this effect. Therefore, fiber laser welding has been difficult to apply the sole. Thus, laser welding monitoring based on plasma measurements have much difficulty in measurements and analysis of signal. In this study, influence of the plasma emission signal according to welding speed and laser power in fiber laser welding analysed by using RMS and FFT analysis. We can verify that RMS value of the plasma emission signal changes with welding parameters in fiber laser welding, and aspect ratio greater than 1, the peak of FFT frequency had been moved in accordance with welding parameter.

API강재의 파이버레이저 용접시 유기하는 플라즈마의 방사특성 (III) - 보호가스가 플라즈마 방사 신호에 미치는 영향 -

이창제,김종도,김유찬,Lee, Chang-Je,Kim, Jong-Do,Kim, Yu-Chan 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.3

Ar, $N_2$, and He are the conventional kind of shield gas that are used for laser welding. Many researches on the impact of laser welding shield gas have been done, and it is on going until now. However, there are few studies that analyze the changes and differences of the plasma emission signal. Therefore, in this study, we evaluated the change in the penetration characteristics according to the type of shield gas during fiber laser welding impacts to the plasma signal. As a result, if was checked that the difference in molecular weight of Ar, $N_2$, and He affects to the amount of spatter, and also found that the measured plasma radiation signal changes similar to the order of the molecular weight of the gases. Especially, clear change on the signal intensity per each shield gas was measured through RMS, and found that the shield gas was nothing to do with the FFT analyzed result.

파이버 레이저의 스테인리스강 용접시 인프로세스 모니터링을 위한 유기 플라즈마와 방사신호간의 상관성 연구(II) - 후판 용접시 측정신호의 특성 변화 -

이창제,김종도,Lee, Chang-Je,Kim, Jong-Do 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.6

On this study, we researched the in-process monitoring during fiber laser welding as well as on the first paper. On the previous/formal study, we analyzed the change of emission signal on thin plate welding. On this study, however, we analyzed RMS and FFT with emission signals in laser welding on lap joint and butt joint of 8mm-thick 316L stainless steel. As the result, the movement of specific frequency peak was observed according to welding speed changes. Furthermore, frequency peak as a result of FFT on the thick plate welding are much clearer than on the thin plate welding. Therefore, it is expected that the welding parameter changes can be predicted in case of applying FFT to in-process monitoring.

대형화면을 이용한 교육선진화

이창제 한국스쿨넷학회 2000 학술발표 논문집 Vol.2000 No.1

디지털 제어를 이용한 알루미늄 아크 용접기의 기술현황

이창제,김유찬,김종도,Lee, Chang-Je,Kim, Yu-Chan,Kim, Jong-Do 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.1

Recently, welding technology of nonferrous metals which were difficult to implement by arc welder has become available through digitalization of arc welding machine. Among them, the welding quality improvement of aluminum welding is very noticeable. These results increase the arc stability by controlling arc current and voltage waveform precisely, and control wire feed speed by synchronizing with arc current which the feed rate of filler wire is controlled by a precise motor control of servomotor and not by a simple constant speed feeding. Not only through the hardware digitalization of arc welding machine but also through advance of software of arc welding, it became possible to implement a certain level of welding quality by a simple operation. These led to CMT welding process implementation which requires low heat input than current arc welding and highly increased the applicability of the aluminum welding.

書籍과敎育

金昶濟 박문서관 1939 博文 Vol.10 No.-

장기요양보호서비스의 비용․효과분석: 시설보호 대 재가보호

박창제 한국노인복지학회 2010 노인복지연구 Vol.0 No.50

The purpose of this study is to analyze the cost-effectiveness of care service in institutions for elderly vs in-home care service represented long term care services in Korea, and derive their implications using the results of analyses. For this research, primary caregivers that utilize in-home care service or care service in institutions for the elderly sanctioned as the elderly requiring institution care (care rank 1th or 2th) by National Health Insurance Corporation were drawn and surveyed. Among collected data, data for 38 primary caregivers utilizing in-home care service and 37 primary caregivers utilizing care service in institutions were used for this study. The results of this study can be summarized as follows. First, for primary caregivers of the elderly with high dependence, care service in institutions for elderly is more effective than in-home care service. Second, cost-effectiveness is different among stressors of primary caregiver. For costs spent to improve by 1 unit, there are role captivity the highest, next loss of intimate exchange, and role overload the lowest among primary stressors., and there were family conflict the highest, the next loss of self, and work conflict the lowest among secondary stressors. Taken together, it cost higher from the family perspective, public perspective, and social perspective but is effective to improve stressors and negative mental health or psychology wellbeing that primary caregiver with the elderly sanctioned as the elderly requiring institution care (care rank 1th or 2th) by National Health Insurance Corporation utilizes care service in institutions rather than in-home care service 본 연구는 우리나라의 가장 핵심적인 장기요양보호서비스인 방문요양서비스와 요양시설보호서비스에 대하여 비용․효과 분석을 수행하고 그 결과를 바탕으로 주요한 정책적 함의를 논의하고자 한다. 연구의 분석 표본은 방문요양서비스 이용자 38부, 노인요양시설 서비스 이용자 37부가 최종 선택되었다. 분석결과는 다음과 같았다. 첫째, 보호욕구가 강하여 요양등급이 높은 노인을 부양하는 부양자에게는 재가 서비스인 방문요양보다 시설보호인 노인요양시설이 스트레스 측면에서 더 효과적이다. 둘째, 스트레스 요인간 비용효과가 다르다. 1차적 스트레스 요인에서는 역할구속의 단위당 개선비용이 가장 낮았고 친교 상실이 단위당 개선비용이 가장 높았다. 2차 스트레스 요인 중에서는 근로갈등이 단위당 개선비용이 가장 낮았고 가족갈등이 단위당 개선비용이 가장 높았다. 셋째, 성과지표 전체에서 우울이 가장 비용․효과적이다. 종합적으로 검토하면 요양등급이 높은 노인을 부양하고 있는 가족은 노인요양시설서비스를 이용하는 것이 방문요양서비스 이용에 비하여 가족, 공적, 그리고 사회적 측면 모두에서 비용은 더 많이 발생시키겠지만 주부양자의 스트레스 요인들과 부정적 정신건강을 개선시키고 심리적 안녕을 증진하는데 효과적이다.