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.

엘리베이터 도어의 거동해석

이종선,손의찬 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-

The objective of this study is to behavior analysis of elevator door. In general, a door system are a device for an elevator in safety. The finite element model was developed to compute stress and strain. ANSYS code was applied for this behavior analysis.

개에서 발생한 수컷 가성 반음양 1례

이기찬,손정민,윤기영,최호정,박성준,이영원,정성목,신상태,조종기 忠南大學校 獸醫科大學 附設 動物醫科學硏究所 2006 動物醫科學硏究誌 Vol.14 No.-

In this report, we present a case of the male pseudohermaphrodite in a beagle dog. The animal was subjected for examination due to enlargement of clitoris that was shown as reddish finger-like structure protruding from the vulva. Visual examination of the internal genitalia revealed that the animal possessed both testes and uterus. Based on the findings of physical examination and exploratory laparotomy, it was tentatively diagnosed as male pseudohermaphrodite. Internal genitalia and enlarged clitoris were removed for the prevention of pyometra and Sertoli cell tumor.

안정적 전력공급을 위한 154kV 변전소 배전선로간 연계운영에 관한 연구

김광호,손명권,정종찬 江原大學校 産業技術硏究所 2009 産業技術硏究 Vol.29 No.B

For a stable supply of electric power, periodical inspection of the electric facilities and repair of the distribution lines are required. In case of any unexpected accidents, looped operation among distribution lines may be necessary in order to supply electricity through the sound lines, separating the faulted lines. As a result of this study, it was found that normal looped operation became impossible when phase difference of the looped distribution lines is more than 3 degrees compared with the voltage supply of the distribution lines. Therefore, for a stable supply of electric power to Chuncheon, it is judged to be desirable that looped operation of the distribution lines coming from the same substation M. Tr Bank shall be performed in principle and in case of looped operation with the substation of different system, looped operation among the lines shall be performed after voltage regulation of the substation M. Tr Bank, maintaining similar voltages and load supply volume in order to avoid phase difference through checking the operation conditions of each substation M. Tr Banks. And when looped operation among the distribution lines is scheduled, voltage regulation schedule has been established so far by calculating maximum supply volume through the transformer of the substation and the maximum load volume through the distribution lines but in the future, looped operation of the distribution lines shall be carried out by removing voltage difference with regulating tap or load of the surrounding transformers, with giving prior notice to the substation operators.

국산 체외 충격파 쇄석기의 음향학적 특성 평가

최민주,이종수,김성삼,조성찬,양형석,손종수,천원기 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

In the study we measured and evaluated the acoustical property of a domestic spark gap type extracorporeal shock wave lithotripsy (ESWL). Altering the discharging medium between the electrodes of the shock wave generator (water, 1% an 10% NaCl electrolyte), we measured shock waveforms and sound pressure level (SPL). For the shock waves produced using the discharging medium, water, it was seen that the shock wave peak pressure went up to 70 MPa, and the SPL was in the range of 90 - 100 dB. As the concentration of NaCl increased in the electrolyte. the SPL did not change much and was shown to increase correlation with the discharging voltage. In the case of the discharging medium. 10% NaCl electrolyte, it was found that the shock amplitudes varied in a narrow range when being high in the concentration of NaCl and were large when being high in discharging voltages. While the stone fragmentation was in process, we measured the acoustic emission and compared their spectral properties.

BaTiO₃단결정의 전왜효과에 관한 연구

이수대,이찬구,손종윤 慶南大學校 附設 工業技術硏究所 1999 硏究論文集 Vol.17 No.-

BaTiO₃단결정의 전왜효과와 압전특성을, 임의의 방향으로 가하는 전기장에 대한 역압전변형분포의 SGP(stereographic projection) 그림과 전왜효과에 의한 전왜변형분포에 대한 SGP그림을 그려 분석하였다. 상유전상에 있을 때 인가된 전기장에 의한 변형은 전왜효과에 의해서만 생기며. 강유전상에 있을 때 인가된 전기장에 의한 변형은 역압전효과와 전왜효과의 중첩 영향을 받는다. 각 상에서의 종적 변형과 횡적 변형의 최대 값과 최소 값을 갖는 방향 및 크기를 구하였고 압전변형과 전왜변형의 크기가 같은 등변형전기장을 계산하였다. The electrostriction and the piezoelectric properties of BaTiO₃ single crystal were analyzed by the SGP(stereographic projection) diagram of the electrostriction strain and the converse piezoelectric strain to the applied electric field. In paraelectric phase the strain is only due to the electrostriction, but in ferroelectric phase it is affected by the converse piezoelectric effect with the electrostriction effect. We obtained the directions and the magnitudes with the maximum value and the minimum of the longitudinal strain and the transversal strain at each phase, and calculated the electric field of the equivalent strain which has the same magnitude of the piezoelectric and the electrostriction.

Cross Hole Type 비 연삭 밀링 인서트의 가공특성에 관한 연구

김택수,이상민,박휘근,채승수,이충석,손일복,김학규,이종찬 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

This paper reports some experimental results on the machining performance of non-ground cross hole type milling inserts. Six kinds of milling inserts were manufactured without using grinding process. Machining experiments were carried out to compare the machining performance of non-ground inserts with that of ground ones. The experimental results indicate that the cutting forces and surface roughnesses of machined surface of both ground and non-ground inserts are comparable.

터빈 로터 디스크 키웨이의 초음파 신호로부터 균열정보의 추출을 위한 신호처리 알고리즘의 개발

이종규(Jong-Kyu Lee),서원찬(Won-Chan Seo),박찬(Chan Park),이종오(Jong-O Lee),손영호(Young-Ho Son) 한국비파괴검사학회 2009 한국비파괴검사학회지 Vol.29 No.5

본 연구에서는 터빈 로터 디스크 키웨이에 발생하는 균열의 상세 정보를 추출하기 위하여 초음파신호처리 알고리즘을 개발하였다. 초음파 검사 시스템에 의한 터빈 로터 디스크 키웨이 시험편의 초음파 신호로부터 B-주사 이미지를 구성하였다. 구성된 B-주사 이미지를 2차원 신호처리를 위한 입력영상으로 이용하여, 전처리, 균열후보영역 검출, 균열영역 판별 및 균열정보 추출의 4단계로 알고리즘을 구성하였다. 개발된 초음파 신호처리 알고리즘을 이용한 실험을 통하여, 개발된 알고리즘이 키웨이 부위에 발생하는 균열의 특징 정보 추출에 의한 균열의 정량적인 평가에 효과적임을 확인하였다. An ultrasonic signal processing algorithm was developed for extracting the information of cracks generated around the keyway of a turbine rotor disk. B-scan images were obtained by using keyway specimens and an ultrasonic scan system with x-y position controller. The B-scan images were used as input images for 2-Dimensional signal processing, and the algorithm was constructed with four processing stages of pre-processing, crack candidate region detection, crack region classification and crack information extraction. It is confirmed by experiments that the developed algorithm is effective for the quantitative evaluation of cracks generated around the keyway of turbine rotor disk.

Comparison of arterial stiffness indices measured by the Colins and SphygmoCor systems

Youn, Jong-Chan,Kim, Jong-Youn,Park, Sungha,Kwon, Jisun,Lee, Hye Sun,Shin, Dong-Ho,Lee, Sang-Hak,Kang, Seok-Min,Hoon Son, Nak,Jang, Yangsoo Springer Science and Business Media LLC 2012 Hypertension research Vol.35 No.12

<P>Arterial stiffness is a known independent predictor of cardiovascular mortality. The Colins system is an easy device and has gained widespread use, but the cutoff value for high-risk central arterial stiffness is not well established. We investigated the correlation between arterial stiffness measured by the Colins system with conventional measurements from the SphygmoCor system. Arterial pulse wave velocity (PWV) and augmentation indices (AIs) were measured on a single visit using two different devices in 948 patients with hypertension or coronary artery disease. Strong positive correlations were observed for PWV values measured by the SphygmoCor and Colins systems. The Colins system measurements accurately predicted high-risk central arterial stiffness, defined as carotid-femoral PWV12?m?s(-1), with an area under the receiver-operating characteristic curve (AUC) of 0.884 (heart-femoral PWV, hfPWV) and 0.830 (brachial-ankle PWV, baPWV) in the training set (N=664). The cutoff values, 11.18 (hfPWV) and 16.17?m?s(-1) (baPWV), showed good discrimination in the validation set (N=284), with sensitivity of 83.3 (hfPWV) and 76.0% (baPWV), and specificity of 74.9 (hfPWV) and 82.6% (baPWV). The SphygmoCor and Colins AI systems also showed moderate positive correlation. The Colins AI system better predicted high-risk central pulse pressure as defined by pulse pressure50?mm?Hg (AUC: Colins, 0.765; SphygmoCor, 0.692; P=0.011). Arterial stiffness measured by the Colins system showed strong positive correlation and agreement with the SphygmoCor system measurement. Cutoff values for high-risk central arterial stiffness in the Colins system need further validation in a prospective study.</P>

Exercise-Induced Vasospastic Angina With Prominent Regional Wall Motion Abnormality

Byeng-Ju Son,Jong-Il Park,Jong-Ho Nam,Chan-Hee Lee,Jang-Won Son,Ung Kim,Jong-Seon Park,Kang-Un Choi 아시아심장혈관영상의학회 2024 Cardiovascular Imaging Asia Vol.8 No.1

In vasospastic angina, exercise typically does not lead to vasoconstriction. We present the case of a patient with an atypical presentation of vasospastic angina, characterized by regional wall motion abnormalities confirmed by exercise stress echocardiography. A 58-year-old female patient presented to the hospital reporting chest pain during both exercise. During the exercise stress echocardiogram, regional wall motion abnormality was confirmed. However, the coronary angiography did not reveal significant lesions. Subsequently, ergonovine test was positive and then exercise induced vasospastic angina was diagnosed. Following medical treatment, the patient’s symptoms showed improvement. This case underscores an uncommon presentation of vasospastic angina in an individual already diagnosed with coronary artery disease, indicating that exercise stress echocardiography could serve as a valuable screening tool for specific types of vasospastic angina.