금속압력용기의 사용 전 음향방출시험

이종오,윤운하,이태희,이종규 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.3

사용하지 않은 새 금속 압력용기에 대하여, 사용 전 음향방출시험을 수행할 때 장비점검, 탐촉자 간 거리, 탐촉자 위치, 전 측정 시스템 점검, 가압방법, 잡음 제거법 및 시험 결과의 평가 등에 대한 절차를 수립하고 현장 응용시험이 수행되었다. 일반적으로 음향방출 시험은 많은 잡음을 포함하는데 시험동안 관찰결과를 기록하여 평가 시 시간 필터링함으로서 잡음을 제거할 수 있었다. The field application of acoustic emission(AE) testing for brand-new metal pressure vessel were performed. We will introduce the test procedure for acoustic emission test such as instrument check, distance between sensors, sensor location, whole system calibration, pressurization sequence, noise reduction and evaluation. The data of acoustic emission test contain many noise signal, these noise can be reduced by time filtering which based on the description of observation during AE test.

신경회로망을 이용한 터빈로타 디스크 키웨이의 결함 검출

이병우,이종오,윤운하,이병우,서원찬,이종규 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.1

최근 터빈 로타 디스크 키웨이에서 많은 응력부식균열이 발견되었으며, 터빈설비의 중대한 파손을 예방하기 위해 이러한 균열은 조기에 검출 및 평가되어야 한다. 본 연구에서는 초음파탐상의 RF(radio frequency) 신호를 역전파 알고리즘에 근거한 신경회로망에 적용하여 키웨이 주변의 균열에 대한 위치, 크기 및 방향성을 평가하였다. 각 반사영역에서 수신된 여러개의 피크로 나타나는 RF 신호를 각 반사영역에 대해 하나의 최대 피크를 가지도록 처리한 후, 트랜스듀서의 위치 정보와 각 반사파의 도달시간이 들어있는 주사 데이터를 작성하였다. 이 주사 데이터로부터 각 반사영역 사이의 시간차이와 트랜스듀서의 위치 정보를 신경회로망에 적용한 결과 키웨이에서 시작된 균열의 위치, 크기 및 방향성을 평가하는데 유용함을 알 수 있었다. A number of stress corrosion cracks in turbine rotor disk keyway in power plants have been found and the necessity has been raised to detect and evaluate the cracks prior to the catastrophic failure of turbine disk. By ultrasonic RF signal analysis and using a neural network based on back-propagation algorithm, we tried to evaluate the location, size and orientation of cracks around keyway. Because RF signals received from each reflector have a number of peaks, they were processed to have a single peak for each reflector. Using the processed RF signals, scan data that contain the information on the position of transducer and the arrival time of reflected waves from each reflector were obtained. The time difference between each reflector and the position of transducer extracted from the scan data were then applied to the back-propagation neural network. As a result, the neural network was found useful to evaluate the location, size and orientation of cracks initiated from keyway.

구획 화재시 창유리 파괴 현상에 관한 실험적 연구

이수경,김종훈,최종운,이정훈 韓國火災ㆍ消防學會 1998 한국화재소방학회논문지 Vol.12 No.3

본 연구는 실제 화재실험을 통하여 구획 화재 시 일어날 수 있는 창유리의 파괴 형태 및 시간 그리고 개구 조건과의 관계 등을 고찰하고자 했다. 화재 시 창유리의 파괴현상은 창호 유리 중간 부분과 프레임 안에 있는 유리부분의 현저한 온도차이로 인한 열응력으로 일어남을 확인했다. 실험 1-3은 프레임 내부와 유리면의 온도차가 233.4℃ 였으며, 실험 2-1은 138℃, 실험 2-2는 83.6℃의 차이를 보였다. 파괴 발생 시 실내의 온도는 실험 2-1의 경우 434.4℃, 실험 2-2는 83.6℃의 차이를 보였다. 파괴 발생 시 실내의 온도는 실험 2-1의 경우 434.4℃, 실험 2-2는 440.6℃ 실험 2-3은 400.9℃를 기록하여 화염이 직접 닿지 않는 경우의 균열은 400 ~ 500℃의 온도에서 발생한다. 화재로 인한 창유리(한글라스 플로팅 유리)는 1541.14kW의 화재에 노출되었을 시 열응력에 의한 파괴가 일어나기는 하나 유리면이 파괴에 의해 개구부가 되지 않는다. This is a study on the relation of window glass breaking time, shape, and vent condition in a compartment fire through the experiment. We recognize the phenomenon that window glass breakage in a compartment fire be arose from the thermal stresses due to the temperature temperature difference was 233.4℃ for test 1-3, 138℃ for text 2-1, 83.6℃ for test 2-2. The interior test 2-2, 400.9℃ for test 2-3. so if the flame didn't reach at the surface of window glass, the breakage of glass occur at 400℃ ~ 500℃. When the fire size reached to 1541.14kW, the window might be broken by thermal stress. But window glass was not collapsed.

접지된 유전체층 위의 유한한 주기적인 스트립격자에 의한 TM회절

이종익,백운석 東西大學校 1999 동서논문집 Vol.5 No.-

TM diffraction of a Gaussian beam wave by finite periodic conducting strip grating on a grounded dielectric slab is considered. The integro-differential equation for the induced strip currents is derived for the case that the spectural bandwidth of the incident Gaussian beam wave is narrow and solved numerically by use of the methid of moments. From results for the angular diffraction pattern, some similarity between scattering behaviours of the proposed finite periodic geometry and the infinite one is examined by observing the off-Bragg as well as Bragg blazing phenomena in the geometry.

구내신연장치를 이용한 치조골증대술 후 임프란트 매식 : 치험 5예 REPORT OF 5 CASES

이용욱,박충열,송종운,박홍주,김영운,오희균,유선열 대한악안면성형재건외과학회 2002 Maxillofacial Plastic Reconstructive Surgery Vol.24 No.2

Successful alveolar ridge augmentation by distraction osteogenesis method has been reported previously. There are several types of devices for alveolar ridge augmentation. In this paper, a new intraoral distraction device was used on the severe atrophic mandible in order to distract an alveolar ridge vertically in 5 patients. Mean amount of distracted alveolar ridge was 7.4㎜ (5∼9.5㎜). Dental implants were placed in the distracted alveolar bone and good osseointegration was obtained in all patients. Mean follow up period is 2years 6months (7months∼4years 9months). No complications, such as infection or resorption was observed in all patients. Alveolar ridge augmentation by gradual distraction seems to be a safe, simple and reliable procedure.

초음파 영상처리용 PCI보드 및 S/W개발에 관한 연구

이종운 東洋大學校 産業技術硏究所 1999 東洋大學校 産業技術硏究所 論文集 Vol.1 No.1

PCI interface board for Ultrasonic image processing used in medical systems and driving software to port on PC architecture are developed. The 4 kinds of image data depending on the operation modes are transferred through its own 8-bits channel and selectively displayed on the monitor with its mode and menu. PCI interface is implemented using chipset from the PLX technology and its RDK and the software to read data and to display received image on the monitor is implemented using MFC library and C++. With the limit of the implementation environment, the result shows the performance is a little lower than the specification. The lower performance reasons and modification ideas are presented to fix the phenomena.

은도금액으로 부터 은이온 회수를 위한 AgCl 결정화에 관한 연구

이종석,김우식,김운수,김용욱 경희대학교 산학협력기술연구원 1995 산학협력기술연구논문집 Vol.1 No.-

For the effective recovery of silver ion from silver plating solution the effects of operating conditions on the reaction crystallization process of silver halide were investigated in single-jet semibatch reactor. In the silver halide reaction crystallization processes the impeller speed, feeding rate and feed concentrations of silver and chloride ions were considered as major operating factors. Since effects of such operating conditions is mainly involved at two processes of generation of supersaturation and particle growth in ths silver halide reaction crystallization, the mean size and size distribution of silver halide particle which were created in the reactor strongly depended on which process is more dominantly influenced by the operating conditions. In the single-jet semibatch reactor for the silver halide reaction crystallization the process of generation of supersaturation was more sensitive to the oprating conditions than the partcle growth process. Thus, the mean particle size of silver halide was decreased with increase of feeding rate, feed concentration and impeller speed. However, the particle morphology of silver halide was unaffected by the variation of the operation conditions.

[논문]부산광역시 지하철역의 오염물질 농도 변화에 관한 연구

이화운,박종길,장난심,이희령,김희만 부산대학교 환경문제연구소 2004 環境硏究報 Vol.22 No.-

on the variation of Air Pollutants concentration in Subway Station at Busan Metropolitan City

평행평판 도파관의 주기적인 슬릿으로 구성된 PBG 구조

이종익,백운석 東洋大學校 産業技術硏究所 1999 東洋大學校 産業技術硏究所 論文集 Vol.1 No.1

In this study, both the infinite periodic strip gratings on a grounded dielectric slab are considered from the viewpoint of photonic band-gap(PBG) structure for TE polarization case. Parallel-plate waveguide(PPW) with finite number of periodic slits in its upper wall is considered as a finite periodic structure. Complex propagation constants(β-jα) of the infinite periodic structure against operating frequency are computed to show the effect of the geometric parameters such as dielectric constant, guide height, strip width on the bandwidth and center frequency of the PBG structure. Reflected and transmitted powers against the operating frequency in the practical finite periodic structure are also computed along with the results of complex propagation constants in the infinite periodic structure.

일방성 GFRP 복합재료에서 음향방출 신호의 위치표정

이종오,원순호,윤운하,이종규,소철호 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.3

General source location method that use an arrival time differences among sensor is restricted to the composite material and the complex-shaped material. In this study, a bundle-type acoustic sensor composed of 6 pinducers was utilized to determine wave propagation direction and then to estimate source location of the unidirectional GFRP. For the purpose of the study, slowness curve for the material was obtained and made an assumption that the incident waves on pinducers are propagated as a plane wave. According to the results, measured propagation directions of the wave was coincide with theoretical background, however, it was a hassle to determine the source location exactly. But, it is expected that bundle-type sensor gives more accurate results for zone location than generally used acoustic sensors.