• 한국구조물진단유지관리공학회 논문집
• /
• 제28권2호
• /
• pp.53-60
• /
• 2024

프리스트레스트 콘크리트(PSC) 교량은 긴장재 부식과 파단에 취약하며, 특히 내부 포스트텐션 형식을 사용하는 구조물은 내부 긴장재 조사의 한계로 유지관리에 어려움이 있다. 따라서 본 연구에서는 고속도로 교량의 약 35%를 차지하는 PSC I 거더교의 트럭 재하 실험을 통하여 긴장재 손상에 따른 실제 거동을 분석하고 유지관리 전략을 제시하고자 하였다. 대상 PSC I 거더교는 고속도로의 폐교량이며, 상·하행교량의 공용기간은 각각 33년, 20년이다. 단부 및 중앙부 등 긴장재 손상 위치와 정적 및 동적, 거더별 하중 재하 방법에 따라 처짐과 콘크리트 변형률을 계측하였다. 교량의 노후화와 관계없이 긴장재 손상이 거더 중앙부에 가까울수록 교량의 구조 성능은 감소하였다. 트럭 하중이 긴장재 절단이 발생한 거더에 근접될수록 거동의 변화가 증가하였다. 긴장재 절단 인접거더에 하중이 재하 될 경우 교량 전체 구조계의 영향으로 구조적 성능은 유지 가능할 것으로 판단된다. 거더 중앙부 긴장재가 절단된 경우 처짐의 변화량은 육안 관찰이 어려운 수준인 반면, 절단 위치의 콘크리트 변형률은 균열발생 변형률을 초과하였다. 따라서 향후 PSC I 거더교의 모니터링 및 유지관리 시에 콘크리트 변형률 또는 균열에 중점을 두는 것이 효율적이라 판단된다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.1672-1677
• /
• 2005

The Heat exchanger to be used in the place of business that is presented an utility period comes to be long and the problem of the length of life shares by the manufacture course and using environment factor. Consequentl, it is came to the front problem of inspection, repair, exchange, the utility stopping, safety and confidence. As a result the possibility which the large safety accident can happen comes to be high. It leads mostly to the large accedent when the explosion accident happens. to keep this, The system which the regular period passes to disuse the structure is prepared but The phenomenon which Time and the strength characteristic of the material change, namely Deradation. but It can't be a preventable solution by accident to the damage. Consequentl, This research can take important role to prevent an every kind accident for domestic pressure vessel by evaluating the mechnical characteristic change of meterial, the structure safety and residual life etc.

• 대한방사선기술학회지:방사선기술과학
• /
• 제41권5호
• /
• pp.479-485
• /
• 2018

Radiologic technologists working at the second and third medical institutions are classified as radiation-related workers and radiation workers according to their working departments, and are subject to double regulation by the Ministry of Health and Welfare and the Nuclear Safety Commission. We will try to understand the system of dualization and to understand the investigation of recognition. The dualized system of radiation-related workers and radiation workers includes the difference in name and terminology, the effective dose limit, the maintenance education and training of radiologic technologists, the period of medical examination, the radiation zone, dose of the woman whose pregnancy is confirmed in radiologic technologists, the qualification criteria of the safety officer, and the period of the regular inspection of the radiological equipment. In the questionnaire survey on the dualization system, there were various items showing significant differences between the radiation-related workers and radiation workers Overall, the radiation workers were more aware of the radiation workers' education and related terms than the radiation-related workers.

• 한국생활과학회지
• /
• 제14권5호
• /
• pp.795-803
• /
• 2005

This paper discusses the late nineteenth-century Korean intellectuals' understanding of Japanese customs on the basis of Ki-Su Kim(金綺秀)'s records. Ki-Su Kim was conservative on his inspection and observation trip to Japan Even though he was loyal to Chinese philosophy, he expressed his great interest when he was reluctant to see the Western technology flowered in Japan because it is not mentioned in Confucianism(朱子學). However, he, like mordern scholars in the later period of the Chosun dynasty, took an objective view of the military matters, such as the military training of soldiers, weapons, and others. On the one hand, he appreciated the western garment in that it, fitting the human body perfectly, makes people comfortable. In the later period of the Chosun dynasty, the Koreans had a sense of their superiority to the Japanese and held them in contempt, which had been rooted in the Japanese invasion of Chosun in the year of Imjin(AD 1592). Even around AD 1870, the Koreans regarded the Japanese as a barbarian or a savage, even though the Japanese had attempted to modernize their country with the introduction of the Western civilization since the renovation of Meizi(明治).

• Journal of Korean Society for Atmospheric Environment
• /
• 제21권E1호
• /
• pp.1-11
• /
• 2005

The concentration levels of gaseous elemental mercury (GEM) in ambient air have been investigated from a monitoring station located in Yang Jae district of Seoul, Korea for a long-term period covering 1997 through 2002. The mean concentration of Hg, if computed based on its hourly measurement data for this six-year period, was $5.32\pm3.53 ng m^{-3} (N = 27,170)$. The inspection of the diurnal distribution patterns indicated the presence of notably high concentration levels during nighttime relative to daytime (e.g., the mean hourly value as high as $9 ng m^{-3}$ in winter nighttime). When divided seasonally, the highest mean of $6.12 ng m^{-3}$ was also observed during winter followed by spring, fall, and summer. The results of our analysis confirmed the relative dominance of winter (seasonally) or nighttime (diurnally), while exhibiting a complicated trend on a long-term basis. Examination of our data over a different temporal scale consistently indicated that dynamic changes in Hg concentrations occurred through time in line with changes in the strength and diversity of the source processes. It is thus acknowledged that the presence of unusually high Hg levels is the consequence of intense man-made activities, while such signatures can vary in a competitive manner.

• 대한기계학회논문집
• /
• 제16권8호
• /
• pp.1503-1512
• /
• 1992

본 연구에서는 열화평가 및 수명예측에 있어서 가장 중요한 문제로 대두되는 기계구조물의 사용시간과 부식 정도에 대한 관계 곡선을 규명하기 위하여 실험실의 가혹 환경하에서 부식을 시키면서 표면을 측정한 데이터로 통계적인 파라메타(parame- ter)를 추정하여, 인공부식시킨 부식재로 피로 강도를 평가하고, 또 부식된 구조물의 잔존수명을 예측할 수 있는 하나의 방법을 제시하고저 한다.

• 한국가금학회지
• /
• 제39권2호
• /
• pp.97-104
• /
• 2012

본 연구는 국내에 서식하고 있는 야생 조류에서의 뉴캣슬 병바이러스(NDV) 감염 분포율을 조사하였다. 본 연구를 위하여 2011년 2월에서 11월에 걸쳐 포획한 8개 목 42종의 야생 조류 1,024수를 대상으로 NDV에 대한 혈청 검사를 혈구 응집 억제 반응법으로 실시하였다. 그 결과, 조사 대상 야생조류 중 12.6%(129/1,024)에서NDV 항체가 검출되었다. NDV 항체가 검출된 야생 조류는 기러기목의 6종(원앙, 청둥오리, 흰뺨검둥오리, 고방오리, 쇠기러기, 쇠오리)과 도요 목의 괭이갈매기였다. 이 중 원앙(27.8%, 32/115), 청둥오리(20.8%, 57/274), 흰뺨검둥오리(11.9%, 36/303)는 10% 이상 높은 항체양성률을 나타내었으며, 고방오리(2.9%, 1/34), 괭이갈매기(2.9%, 1/34), 쇠기러기(1.8%, 1/56), 쇠오리(1.4%, 1/69)는 3% 미만의 낮은 NDV 항체 양성률을 나타내었다. 그러나 나머지 6개목 35종의 야생 조류에서는 NDV 항체가 검출되지 않았다. 항체 양성률이 높은 원앙, 청둥오리, 흰뺨검둥오리를 대상으로 시기별 조사한 결과, 원앙의 경우 11월 25%(24/96), 2월 42%(8/19)의 항체 양성률을, 청둥오리의 경우 10월 33%(1/3), 11월 25%(26/104), 2월 21.1%(19/90), 3월 14.3%(11/77)의 항체 양성률을, 흰뺨검둥오리의 경우 10월 4.5%(2/44), 11월 12.2%(12/98), 2월 16.4%(9/55), 3월 12.3%(13/106)의 양성률을 보였다. 본 연구 결과는 국내에서 서식하는 원앙, 청둥오리, 흰뺨검둥오리 등 야생 오리류가 NDV의 주된 자연 숙주이며, NDV 감염은 10월과 11월 사이에 감염이 급증하기 시작하여 동절기 동안 순환 감염이 일어나는 계절적 특성을 보이는 있음을 나타낸다.

• 제어로봇시스템학회논문지
• /
• 제11권9호
• /
• pp.774-780
• /
• 2005

For the accurate inspection of the resources and space in the ocean, the method of locating the measurement equipments in the seafloor and retrieving these equipments later after a certain period of time. is generally used. In this method, the reliability of retrieving measurement equipments is very important. In our proposed remotely-controlled acoustic release system, an underwater ultrasonic wave recognition algorithm by which we can recognize the sound signal without the influence of disturbances due to underwater environment changes is developed, and a battery is used for the reduction of electric power consumption. we show the effectiveness of our proposed system through experimental results.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.275-280
• /
• 2011

Due to high-speed of trains, the track deformation increases rapidly and may lead to track irregularities causing the track stability problem. To secure the track stability, the continual inspection on track irregularities is required. The paper presents a methodology for identifying track irregularity using the NARX neural network considering non-linearity in the train structural system. A simulation study has been carried out to examine the proposed method. Acceleration time history data measured at a bogie were re-sampled to every 0.25m track irregularity. In the simulation study, two sets of measured data were simulated. The second data set was obtained by a train with 10% more mass than the one for the first data set. The first set of simulated data was used to train the series-parallel mode of NARX neural network. Then, the track irregularities at the second time period are identified by using the measured acceleration data. The closeness of the identified track irregularity to the actual one is evaluated by PSD and RMSE.

• 한국환경보건학회지
• /
• 제28권5호
• /
• pp.71-76
• /
• 2002

A survey of radon concentrations in both indoor and outdoor atmospheres was carried out using EIRM and Cup Monitor for the period of February 1996 to March 1997. EIRM were used to measure the indoor and outdoor radon concentration at five major cities university. Cup Monitor were also used to measure the indoor radon concentrations at shopping store, office building, apartment, hospital and house in Seoul. The mean indoor and outdoor radon concentrations at the five major cities(Seoul, Daegu, Daejon, Cwangiu and Busan) were 24.1 Bq/m$^3$and 8.62 Bq/m$^3$, respectively. The ratio of indoor to outdoor radon concentrations ranged front 1.7 to 3.9. Inspection of its seasonal distribute pattern indicates the enhancement during winter relative to summer, consistently for both indoor and outdoor air. The results of the survey showed that the concentrations in basements were clearly higher than those in usual living/working places.