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반도체 레이저 펌핑에 의한 Cr:LiSAF 레이저의 출력 특성
김칠민,박종대,윤장한,이일형,조창호 培材大學校 1996 培材論叢 Vol.1 No.-
반도체 레이저에 의해 펌핑되는 Cr:LiSAF 레이저를 제작하였다. 펌핑 레이저는 고출력의 적색 반도체 레이저(SDL 7432-H1) 였으며, 674 nm에서 최대 500 mW의 출력을 낼 수 있다. 레이저 결정은 plano-Brewster 모양의 Cr:LiSAF 으로 Cr³+의 농도가 3%, 길이가 3 mm, 결정의 평면인 면은 펌프레이저를 최대로 투과하고, 800-880 nm 대역에서 최대 반사율을 갖도록 코팅된 것을 사용하였다. 결정에 의한 비점수차를 보정하기 위해 V자형 공진기를 사용하였다. 펌핑레이저의 출력이 290 mW일때, Cr:LiSAF 레이저의 출력은 19.4 mW이었으며 850-870 nm 대역의 여러 종모드가 발진하였다. A Cr:LiSAF laser which was pumped by semiconductor lasers was constructed. The pumping laser was a high-power red semiconductor laser (SDL 7432-H1) of wavelength 674 nm and maximum power of 500 mW. The laser crystal was a Cr:LiSAF in plano-Brewster shape with 3% Cr³+ ion concentration and the length was 3 mm. The plane facet of the crystal was coated to have the maximum transmittance of pumping laser and to have maximum reflection over the 800 - 880 nm bandwidth. A V-shaped resonator was used to compensate the astigmatism induced by the crystal. The optical power of the Cr:LiSAF laser was 19.4 mW at the pumping power of 290 mW and many longitudinal modes were oscillated over the spectrum ranging from 850 nm to 870 nm.
유전체로 둘러싸인 속빈 직육면체 도파관을 사용한 레이저 공진기에서 횡특성모드의 왕복손실
金允溟,金永植,李鍾旿,徐七成,박재우 단국대학교 1989 論文集 Vol.23 No.-
The round-trip losses of CO_2 laser wavelength in a hollow rectangular dielectric waveguide with external spherical mirrors are calculated. The propagative attenuations of some higher order modes with different polarization are analyzed as well as EH_11 fundamental mode. Computations of the losses in coupling radiation of various modes from the guide into free space and back into the guide, as a function of mirror curvature and position, are also presented. The overall return losses of various modes are the sum of the two kinds of losses.
Nathan's Promise to David in Qumran
Park,Jong Chil 高神大學校 1985 論文集 Vol.13 No.-
This promise is quoted in Qumran(4Q Flor), in Rabbinic Literature and in the New Testament. It is also alluded to many times in the Old Testament. Ⅰ. The meaning of the Promise as found in the Old Testament. A. In Ⅱ Sam. 7:5-17. The general tendency of critical scholars who comment on the promise of Nathan to David, is to show deuteronomistically redacted elements attributed to the Prophet Nathan and directed to David. But God, who delivered Israel from Egypt, gave a sure and direct promise to David through Nathan at a turning point of progressive revelation. R. Kittel, who accepts a deuteronomic revision, admits the historical inviolability of this revelation :
박종칠(Park Jong Chil),길흥배(Gil Heung Bae),강상규(Kang Sang Gyu),임채운(Lim Chae Woon) 대한토목학회 2010 대한토목학회논문집 A Vol.30 No.4A
본 논문은 GNSS 데이터를 이용한 사장교의 고유진동수와 모드형상 추출을 다루고 있다. 서해대교 사장교에 설치된 6개의 GNSS 측정점으로부터 응답신호를 얻어 동특성 분석에 사용하였다. 측정된 GNSS 신호에 대해 정규화 과정과 버터워스 필터를 사용하여 관심영역의 신호를 분리한 뒤, 이중 미분을 수행하여 가속도 데이터로 변환하였다. 변환된 가속도에 대한 FFT 분석을 통해 5개의 고유진동수를 추출하였으며, 이를 기존 연구결과와 비교 검증하였다. 또한 TDD기법을 이용하여 GNSS 데이터로부터 교량의 모드형상까지 추출할 수 있었다. This paper presents the extraction of natural frequencies and mode shapes of a cable-stayed bridge using data acquired from GNSS. The response signals of 6 GNSS measuring points installed at the Seohae cable-stayed bridge are used for analysis of dynamic characteristics. Using normalization process and a third order Butterworth filter for the measured signals, the related pass band's signals have been isolated. Then, the acceleration data by double differentiation for these signals are obtained. Total five natural frequencies have been extracted by the fast Fourier transform and compared to the results of different studies. For the acceleration obtained from GNSS signals, the mode shapes of the bridge have been successfully extracted by TDD technique.
금속작업자의 피부질환에 관한 연구 ( II . 알레르기성 접촉피부염 )
박종일 ( Jong Il Park ),김희옥 ( Hee Ok Kim ),박시룡 ( See Ryong Park ),오칠환 ( Chil Hwan Oh ),김순덕 ( Soon Duck Kim ),염용태 ( Yong Tae Yeum ) 대한피부과학회 1998 대한피부과학회지 Vol.36 No.2
Background: Skin contact with metalworking fluid(MWF) remains a frequent cause of occupational dermatitis. However, no precise data is available about sensitization in metalworkers exposed to MWF in Korea. Objectives : The purpose of this study was to evaluate the prevalence of contact sensitivity among metalwokers who handle MWFs and to investigate the suitability of a screening test with MWFs being actually used in metalworkers. Methods: An epidemiological study was performed using a ' questionnaire in 771 workers in 9 derpartments of a motor company. 278 out of 771 workers had actual contact with MWF. Patch tests were performed in 73 metalworkers who had suspected dermatits in relation to exposure of MWF, which was selected via interviews and dermatologic examinations. Patch tests were included with a routine series of common components of MWF(materials obtained from Chemotechnique, Sweden), a solvent series and several dilutions of various crude MWFs(8 species) Results : Contact sensitization was established in 14 metalworkers(5% of 278). Sensitising substances were biocide(6 cases), corrosion inhibitors(2 cases), emulsifiers(2 cases), biostatic substances(1 cses) and others(4 cases). Therefore 10 out of 14 metalworkers had true occupational allergic contact dermatitis. 10 out of 73 screening patch tests showed positive reactions to MWF elements, and 9 people who were positive to MWF elements showed positive reactions to crude MWF, but 1 person did not. Conclusion : The prevalence of occupational allergic contact dermatitis(3.5% of 278) was low. The screening patch test by crude MWFs actually used in metalworkers may give false negatives. Therefore for the purpose of diagnosis of allergic contact dermatitis, we need a process of patch tests with MWF elements. (Korean J Dermatol 1998;36(2) 246-251)
장대교량 건전성 모니터링을 위한 이동식 계측시스템 제안
박종칠 ( Park¸ Jong-chil ),신유성 ( Shin¸ Yooseong ),서정욱 ( Seo¸ Jeong-wook ) 한국구조물진단유지관리공학회 2023 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.27 No.2
최근 들어 케이블교량 및 노후 교량, 특수한 여건에 놓인 중소 규모의 교량에서 건전성 모니터링 적용 사례가 증가하고 있다. 이들 교량에 설치되는 계측기기 대부분은 소정의 위치에 견고히 장착되고 유선 방식이여서 이동성과 공간 활용성이 떨어지는 문제점을 갖고 있다. 이에 주행과 움직임이 가능한 형태의 원격조작 이동체에 센싱 기능을 탑재하여 이동성과 활용성을 향상시킨 교량 모니터링 로봇시스템을 개발하고 있다. 바퀴 주행형 이동체는 주이동체와 부이동체로 구성되며, 비부착식 센싱 모듈은 유/무선 센서, PTZ 카메라, GNSS RTK 기기로 구성된다.