무증상 대퇴골두 무혈성 괴사의 증상발현

원중희,김용민,최의성,이호승,서중배,배병권 대한고관절학회 2001 Hip and Pelvis Vol.13 No.1

소음 특수건강진단 1차검사의 민감도와 특이도에 미치는 일과성 역치 상승과 주변환경 소음의 영향

원종욱,방문규,송중호,정선아,송재석,노재훈 대한산업의학회 2000 대한직업환경의학회지 Vol.12 No.2

Object : This study was performed to increase the sensitivity and specificity for screening the examinee of second hearing test. Methods : Study subjects were 219 workers who exposed more than average 80dB. They were taken the hearing test two times, before noose exposure and at 1 hour to 4 hours after worksite noise exposure. To investigate the ambient noise workers who were taken the hearing test in the test room which ambient noise was less than 45dB were classified Group I and the others were classified Group II . To calculate the sensitivity and specificity we made it gold standard whether worker had noise induced hearing loss. Results : Difference of hearing loss between before and after noise exposure for left and right ear was 11.4 dB and 11.7 dB respectively at 500 Hz, 8.7 dB and 9.6 dB at 1,000 Hz, 6.3 dB and 6.9 dB at 2,000 Hz and 6.9 dB and 7.4 dB at 4,000 Hz In Group I. That for left ear and right ear was 5.8 dB and 4.9 dB at 500 Hz respectively, 5.4 dB and 6.4 dB at 1,000 Hz, 6.3 dB and 5.3 dB at 2,000 Hz, and 5.5 dB and 5.8 dB at 4,000 Hz in Group II. The sensitivity was 100 in both Groups and the specificity was increased to 58.3 and 71.8 in Group I and Group II respectively until 10 dB was deducted from hearing level at 1,000 Hz and 4,000 Hz. Conclusion : When the screening hearing test was performed at worksite, we might deduct 10 dB from measured hearing level to increase the specificity without reduction of sensitivity.

브레이징 온도 변화에 따른 ZrO2와 Ti-6Al-4V의 접합 특성

기세호,박상윤,허영구,정재필,김원중 大韓齒科補綴學會 2012 대한치과보철학회지 Vol.50 No.3

Purpose: In this study, brazing characteristics of ZrO2 and Ti-6Al-4V brazed joints with increasing temperature were investigated. Materials and methods: The sample size of the ZrO2 was 3 mm × 3 mm × 3 mm (thickness), and Ti-6Al-4V was 10 mm (diameter) × 5 mm (thickness). The filler metal consisted of Ag-Cu-Sn-Ti was prepared in powder form. The brazing sample was heated in a vacuum furnace under 5 × 10-6 torr atmosphere, while the brazing temperature was changed from 700 to 800℃ for 30 min. Results: The experimental results shows that brazed joint of ZrO2 and Ti-6Al-4V occurred at 700 - 800℃. Brazed joint consisted of Ag-rich matrix and Cu-rich phase. A Cu-Ti intermetallic compounds and a Ti-Sn-Cu-Ag alloy were produced along the Ti-6Al-4V bonded interface. Thickness of the reacted layer along the Ti-6Al-4V bonded interface was increased with brazing temperature. Defect ratios of ZrO2 and Ti-6Al-4V bonded interfaces decreased with brazing temperature. Conclusion: Thickness and defect ratio of brazed joints were decreased with increasing temperature. Zirconia was not wetting with filler metal, because the reaction between ZrO2 and Ti did not occur enough. 연구 목적: 온도 변화에 따른 ZrO2와 Ti-6Al-4V의 접합 특성에 대해 알아보기 위하여 새로운 브레이징 합금을 제조하고, 브레이징 온도가 접합 특성에 미치는 영향에 대하여 조사하고자 하였다. 연구 재료 및 방법: 본 연구에서 사용된 시편으로는 실험용 ZrO2 모재(ZirBlank-PS, Acucera, Inc., Gyeonggi-do, Korea)는 소결 전의 블록형태(65 mm × 36 mm × 12 mm (t))이며, 이를 잘라 사포(#2400)로 표면연마 후 소결하였다. 소결된 ZrO2 시편의 크기는 3 mm × 3 mm × 3 mm (t) 이다. Ti-6Al-4V 모재(Ti 6Al 4V ELI CG Bar, TMS, Washington, USA)는 직경 10 mm × 5 mm (t)를 사용하였다. 소결된 ZrO2와 Ti-6Al-4V의 접합을 위하여 브레이징 합금을 제조하였다. 시편을 3군으로 나누어A군은 700℃에서, B군은 750℃에서, C군은 800℃에서 각각 브레이징 하였다. 브레이징 부의 두께와 결함율의 측정은 각 군당 하나의 시편으로 각 시편 당 5회씩 반복 측정하여 평균값을 취하였다. 결과: 브레이징 합금을 사용하여 진공 브레이징을 수행한 결과 ZrO2 와 Ti-6Al-4V 는 700℃ - 800℃에서 양호한 접합을 보였다. 브레이징 후 브레이징 온도 변화에 따른 브레이징 부의 두께 및 결함율의 변화는SEM을 사용하여 측정하였다. 브레이징 온도가 700℃에서 800℃로 증가함에 따라 CuTi 금속간 화합물 층 및 Ti-Sn-Cu-Ag계 화합물 층의 두께는 각각 4.5 ㎛에서 10.3 ㎛로, 3.1 ㎛에서 5.0 ㎛로 증가되었다. 또한 브레이징 온도가 700℃에서 800℃로 증가함에 따라 브레이징 접합계면의 결함율은 ZrO2 및 Ti-6Al-4V 계면에서 각각25%에서 16.3%, 5%에서 1.5%로 감소되었다. 결론: 브레이징 온도가 700℃에서 800℃로 증가됨에 따라, 브레이징 접합계면의 결함율은 ZrO2 및 Ti-6Al-4V 계면에서 모두 감소되었다. 이는 결함부에서 ZrO2와 활성원소인 Ti과의 반응이 충분히 일어나지 않아서 브레이징 합금이 ZrO2에 웨팅되지 않은 것이 원인이라고 사료된다.

연속형 센서와 웨이브 전파를 이용한 판 구조물의 손상감지

이종원,최광호,이중원 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.4

Abstract : The response characteristics of long continuous sensors are studied for damage detection in a plate structure based on strain waves that are generated by damage. That is, the response characteristics of the long continuous sensors, which are long ribbon-like sensors and can be fabricatedby piezoceramic ribbon fibers, etc. are studied by simulation of wavepropagation in a panel to improve sensing capability of the waves that arepropagating by damage. The advantage of the long continuous sensor is toimprove damage detection by having a large coverage of sensors on thestructure using a small number of channels of data acquisition. Theresponses from the long continuous sensor are similar if the damages arelocated at the same normal distance to the sensor, and these similar patternscan make it easy to estimate the damage. Keywords : long continuous sensor, damage detection, wave propagation 요지 : 이 연구에서는 손상에 의해 발생하는 변형률 웨이브 검출을 통한 판 구조물의 손상위치추정을 위하여 연속형 센서의 응답특성에 대하여 연구하였다. 즉, 균열발생 및 균열진전등과 같은 손상에 의하여 발생되는 웨이브를 보다 효과적으로 감지하기 위하여, 피에조 세라믹 섬유 등을 이용하여 리본 형으로 길게 제작할 수 있는 연속형 센서의 응답특성을 웨이브 전파 시뮬레이션을 통하여 연구하였다. 이러한 센서를 적용하는 경우, 적은 수의 데이터 취득 채널을 이용하여 구조물의 넓은 영역을 감지할 수 있는 장점이 있다. 또한 연속형 센서와 여러 손상위치들의 직각거리가 같은 경우 센서에서 감지되는 각각의 응답들은손상위치들에 대해 거의 동일한 양상을 보이며, 이러한 응답패턴을 이용하면 판 구조물의손상위치를 더욱 효과적으로 추정할 수 있을 것으로 판단된다. 핵심용어: 연속형 센서, 손상추정, 웨이브 전파

이면성 및 도플러 심초음파도를 이용하여 진단한 선천성 거대 좌회선지-좌심실 관동맥루

진승원,박준철,이영중,유병현,박현옥,김용주,윤호중,김재형,홍순조,최규보,권종범,원용순,박건 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.4

PG의 부제 Building Block의 합성 연구

임중기,함원훈,박호군 성균관대학교 약학연구소 1990 成均藥硏論文集 Vol.2 No.1

Abstracts-Prostaglandins exhibit diverse pharmacological properties and are now recognized as local hormones that control a multitude of important physiological process. (R)-4-hydroxy-2-cyclope-ntenone is a very useful intermediate to synthesize the prostaglandin derivatives. The optically active cyclopentenone building blocks were synthesized in various ways ; by resoultion of the racemic hydroxy ketone ; by preparation from chiral natural products via resolved synthetic intermediates, by asymmetric synthesis, by microbial or enzymatic techniques, etc. The hydroxy ketone can be produced by preparation from chiral building block via microbial organisms. The key chiral building block is dimethyl-5-hydroxy-4R-hydroxy-2-oxopentane phosphate which can be synthesized the optically active cyclpentenone via Horner Emmon reaction. This paper describes the preparation of the chiral diol compound 2 in detail.

승용차 완충장치의 고주파 소음전이 구조해석에 관한 연구

김대원,최영휴,신중호 國立 昌原大學校 産業技術硏究所 1995 産技硏論文集 Vol.9 No.-

Study on new and high technology as electronic control system is used in shock absorber is being carried out but good quality of shock absorber can not be developed without further study on the improvement of noise magnitude, friction resistance reduction, temperature characteristics, damping force scattler reduction which is basic performance in shock absorbers. This study was carried out to clarify transmitted structure, using experimental and theoretical method for high frequency transmitted noise which is one type of structural born noises in the shock absorbers and to analyze the relationships between the high frequency transmitted noise and the characteristics of each component in the passenger car shock absorbers.

심첨부 비후 심근증에서 심근 내 미세 관상동맥의 혈류 예비력 평가 : 경흉부 도플러 심초음파를 이용한 연구 Study Using Transthoracic Doppler Echocardiography

윤호중,박철수,신재원,임상현,조은주,정해억,전희경,오용석,정욱성,김재형,최규보,홍순조 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.3

하계 실내 및 실외환경의 공기 중 휘발성 유기화합물 농도 및 개인노출

양원호,손부순,박종안,장봉기,박완모,김윤신,어수미,윤중섭,류인철 한국환경과학회 2003 한국환경과학회지 Vol.12 No.9

Volatile organic compounds (VOCs) are present in essentially all natural and synthetic materials from petrol to flowers. In this study, indoor and outdoor VOCs concentrations of houses, offices and internet-cafes were measured and compared simultaneously with personal exposures of each 50 participants in Asan and Seoul, respectively. Also, factors that influence personal VOCs exposure were statistically analyzed using questionnaires in relation to house characteristics, time activities, and health effects. All VOCs concentrations were measured by OVM passive samplers (3M) and analyzed with GC/MS. Target pollutants among VOCs were Toluene, o-Xylene, m/p-Xylene, Ethylbenzene, MIBK, n-Octane, Styrene, Trichloroethylene, and 1,2-Dichlorobenzene. Indoor and outdoor VOCs concentrations measured in Seoul were significantly higher than those in Asan except Ethylbenzene. Residential indoor/outdoor (I/O) ratios for all target compounds ranged from 0.94 to 1.51 and I/O ratios of Asan were a little higher than those of Seoul. Relationship between personal VOCs exposure, and indoor and outdoor VOCs concentrations suggested that time-activity pattern could affect the high exposure to air pollutant. Factors that influence indoor VOCs level and personal exposure with regard to house characteristics in houses were building age, inside smoking and house type. In addition insecticide and cosmetics interestingly affected the VOCs personal exposure. Higher exposure to VOCs might be caused to be exciting increase and memory reduction, considering the relationship between measured VOCs concentrations and questionnaire (p<0.05).

고유함수전개법을 이용한 비대칭 유전체 원주공진기의 공진특성해석

류원열,민경호,장중호,전오곤,이창화,최현철 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

The resonant frequency of the dielectric rod resonator which is surrounded by cylindrical cavity can be calculated very exactly by using eigenfunction expansion method in the concept of electric and magnetic wall from the symmetry. But if the supporter is put in the cavity, the symmetry disappears. Thus this method has some errors. In this paper, the resonant frequency of the asymmetric dielectric rod resonator was calculated by using the eigenfunction expansion method. Also, the effect of the supporter was discussed. Then we found that the resonant frequency was more affected in the case of TM mode than TE or Hybrid modes as the length of the supporter was longer.