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.

Hall 소자를 이용한 승강기용 로프의 평가

이종오,윤운하,손영호,김정우,이종규 한국비파괴검사학회 2003 학술대회 논문집 Vol.- No.1

홀 소자를 이용한 누설자속 측정으로 승강기용 와이어 로프의 결함 검출에 대한 연구를 수행하였다. 소선파단, 마모, 내부 소선파단 형태의 인공결함을 제작하여 시험편에 영구자석으로 자장을 걸어 결함에서 누설되는 누설자속을 홀 센서를 사용하여 검출하였다. 로프의 소선은 0.5, 0.8mm 두 종류로 시험결과 단선모델 시험에서 0.4mm, 내부의 소선 파단의 경우 1mm 정도 깊이를 가진 인공결함까지 검출이 가능하여 1개의 소선 파단도 검출할 수 있는 것으로 보인다. 마모모델에서 결함의 폭이 작은 경우 검출이 불가능하였으나, 폭이 4mm이상인 경우 자극이 결함을 통과할 때 자속의 변화에 의해 깊이가 0.2mm 정도의 작은 결함도 구별이 가능하였다. 따라서 Hall 센서에 의한 누설자속 측정이 wire rope의 결함 검출에 좋은 도구가 된다고 본다. Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4mm and 1mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2mm in depth at 4mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.

Escherichia coli(M15)을 이용한 serotonin N-acetyltransferase 유전자의 발현

김용만,정미영,윤경식,진병관,백행운,조용호,백형환 慶熙大學校 1997 論文集 Vol.26 No.-

AA-NAT cDNA was obtained by RT-PCR technique from total RNA of rat sacrified at night(02:00am). pCRNAT was cloned using the pCRII vector with insertion of AA-NAT cDNA(about 1.4 kb) at EcoRI site. For the expression of the gene, pQECNAT was subcloned, in which the coding region of AA-NAT was inserted into expression vector pQE30 at BamHI and HindIII sites. According to the experimental results, Escherichia coli strain M15, transformed by the expession vector pQECNAT, was selected as a host to express AA-NAT gene with the induction of isopropyl β-D-thiogalactoside(IPTG). Optimal condition for the expression of AA-NAT gene was achieve from the experimental results, showing that the expression of the protein was inducible much 19.800 ± 2,200 dpm per ml of culture volume in 4 hours at the concentration of 2 mM IPTG. Partial purification through the affinity column(Ni-NTA agarose) binding to the continuous 6 histidine residues of protein resulted in 5 times more increase in the specific activity of AA-NAT than that of the homogenate of bacterial pellet. These experimental results will provide basic data in further study for the enzymatic kinetics and antibody production of AA-NAT.

망막아세포종 세포주(Y-79)의 Arylalkylamine N-acetyltransferase 활성에 미치는 Dopamine의 영향

김석민,정미영,윤경식,진병관,백행운,백형환,조용호 慶熙大學校 1997 論文集 Vol.26 No.-

The arylalkylamine N-acetyltransferase(AA-NAT, EC 2.3.1.87) in vertebral pineal gland and retina is rate-limiting enzyme in the pathway of biosynthesis of melatonin. AA-NAT activities are remarkably increased during night with 10-150 folds. Neurohormone melatonin is thought to play roles in a broad range of physiological functions in human, primarily through effects on the biological clock in the suprachiasmatic nucleus of the hypothalamus, This rhythm reflects large changes in the activities of AA-NAT. So the important regulatory role of AA-NAT has made it central interest in research on melatonin biochemistry and neurochemical signal transduction. The neurotransmitter that regulates the AA-NAT activities is norepinephrine, which acts through a cyclic AMP mechanism. The effect of dopamine on AA-NAT in human retinoblastoma Y-79 cells was studied. the obtained results are as follows; AA-NAT activities in Y-79 cells were increased by cyclic AMP, and dopamine inhibited the AA-NAT activities stimulated by forskolin. The pattern of inhibition of dopamine on the AA-NAT activities in Y-79 cells was time and concentration dependent. The results suggest that dopamine participates in the regulation of the AA-NAT activities through the inhibitory mechanism in the human pineal and retinal tissues.

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.

상지 단순반복작업 근로자의 수근관 증후군 유병률에 관한 조사

손지언,장태원,김윤규,홍영습,정갑열,김동일,이강진,하남진,김상범,김준연 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.3

목적 : 본 연구는 수근관 증후군의 발생위험이 높은 작업형태에 종사하는 상지 단순반복작업근로자로서 육류 및 어류 가공 사업장과 목재소 근로자에서 근전도검사를 이용하여 수근관 증후군의 유병률을 조사하고자 하였다. 방법 : 상지 단순반복작업근로자로서 육류 및 어류 가공 사업장 근로자 69명과 목재소 근로자 17명을 실험군으로, 관리직, 경리, 경비등 상지의 단순반복작업이 없는 근로자 28명을 대조군으로 선정하여, 작업적 및 병력조사, 이학적 검사와 근전도검사를 통해 수근관 증후군의 유병률을 조사하였다. 결과 : 수근관 증후군의 유병률은 육류 및 어류 가공 사업장과 목재소에서 각각 26.09 % (18명)와 29.41 %(5명)로 조사되었으며, 육류 및 어류가공사업장과 목재소 근로자를 '7년 이상과 미만의 작업기간'으로 층화하여 비교한 결과 '상지부위의 통증 호소 유무', 'Visual Analogue Scale(VAS: 총 10점) 4점 이상 여부', 'Tinel teat 양성 유무', 'Phalen test 양성 유무'는 모두 단기 작업근로자군에서 양성의 빈도가 증가되었고 '수근관 증후군 유무'는 장기작업근로자군에서 양성의 빈도가 증가되었다. 결론 : 육류 및 어류 가공 사업장과 목재소의 수근관 증후군 유병률은 각각 26.09 %와 29.41 %로 육류 및 어류 가공 사업장과 목재소는 1996년 OSHA가 지정한 바와 같이 위험한 작업요인이 있는 작업장으로 분류하여 관리되어야 할 것으로 생각된다. Objectives : This study was carried out to survey on the prevalence of Carpal Tunnel Syndrome(CTS) in high risk jobs(meat and fish processing plant and wood plant), by application of Nerve Conduction Study(NCS), a confirmatory diagnostic method. Methods : Experimental group was 69 workers sampled from meat and fish processing plants and 17 workers sampled from wood plants, who were simple, repetitive workers using upper extremities and control group was 28 workers sampled from managers, secretaries and keepers. All employees were examined through work history, physical examination and NCS. Results : 18 workers(26.09%) in meat and fish processing plants, and 5 workers(29.41%) in wood plants had compatible findings to NIOSH diagnostic criteria for CTS. The experimental group had more symptoms (complaint of upper extremities, Visual Analogue Scale ≥4(VAS: total 10 point)), signs(Tinel and Phalen test) and prevalence of CTS than control group(p<0.05). The prevalence of symptoms and signs were higher in short term workers(<7 years), but the prevalence of CTS was higher in long term workers(≥7 years). Conclusions : The prevalence of CTS in meat and fish processing plant and wood plant were 26.09% and 29.41% respectively. Authors propose that meat and fish processing and wood plants should be managed as a risk job category which were designated by OSHA in 1996

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.

간세포암종에 대한 간동맥 화학색전술 후 발생한 급성호흡곤란증후군

조윤원,이정미,최자윤,유동훈,차라리,오혜원,김홍준,민현주,김현진,정운태,이옥재,하창윤,이선영 이화여자대학교 의과학연구소 2013 EMJ (Ewha medical journal) Vol.36 No.1

Transcatheter arterial chemoembolization (TACE) has become an effective alternative treatment strategy for patients with inoperable hepatocellular carcinoma (HCC). Although TACE is relatively safe, acute respiratory distress syndrome associated with pulmonary lipiodol embolism is a rare and potentially fatal complication. We report a rare case of acute respiratory distress syndrome after TACE for inoperable HCC. A 75-year-old man, with huge HCC in right lobe, was treated by TACE for the first time. Seven hours after uneventful TACE procedure, he felt dyspneic and his oxygen saturation recorded by pulse oximetry (SpO2) fell to 80% despite of applying non-rebreathing mask. He underwent mechanical ventilation with a protective ventilatory strategy. We experienced a case of acute respiratory distress syndrome after TACE for HCC.

Enhanced Thermoelectric Properties of Textured Ca3Co4O9 Thick Film by Aerosol Deposition : Rapid Communications of the American Ceramic Society

Yoon, Woon-Ha,Ryu, Jungho,Choi, Jong-Jin,Hahn, Byung-Dong,Choi, Joon Hwan,Lee, Byoung-Kuk,Cho, Jae-Hyung,Park, Dong-Soo Wiley (Blackwell Publishing) 2010 Journal of the American Ceramic Society Vol. No.

산화막의 질화 조건에 따른 트랩 파라미터에 관한 연구

윤운하(Woon Ha Yoon),강성준(Seong Jun Kang),정양희(Yang Hee Joung) 한국전자통신학회 2016 한국전자통신학회 논문지 Vol.11 No.5

본 논문은 RTP법으로 산화막을 질화시킨 질화산화막으로 MIS 커패시터를 제작하여 avalanche 주입에 따른 캐리어 트랩 특성을 조사하였다. avalanche 주입에 의한 flatband 전압 변화는 두 번의 turn-around가 관찰되었는데 이는 처음 산화막에서 전자 트래핑이 있어나고, 전하 주입에 따라 홀 트래핑에 의한 turn-around 후 다시 전자 트래핑이 일어나는 것을 관찰하였다. 질화 산화막의 캐리어 트랩 파라미터를 결정하기 위하여 실험 결과를 기초로 종류가 다른 여러 트랩을 갖는 계에 대한 캐리어 트래핑을 비교한 결과 실험값과 일치함을 확인하였다. In this paper, the MIS(: Metal-Insulator-Semiconductor) Capacitor with the nitrided-oxide by RTP are fabricated to investigate the carrier trap parameters due to avalanche electron injection. Two times turn-around phenomenon of the flatband voltage shift generated by the avalanche injection are observed. This shows that electron trapping occurs in the oxide film at the first stage. As the electron injection increases, the first turn-around occures due to a positive charge in the oxide layer. After further injection, the curves turns around once again by electron captured. Based on the experimental results, the carrier trapping model for system having multi-traps is proposed and is fitting with experimental data in order to determine trap parameter of nitrided-oxide.