• Journal of Conservation Science
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• v.27 no.4
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• pp.345-356
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• 2011

To remove metal stains of the ceramics, chemical cleaning is essential case by case. This study investigated the removal characteristics of iron stains by oxalic acid and citric acid including their application methods of soaking and poultice. The soaking method in cleaning agents showed removal process by color difference and released iron contents from iron stains on ceramics. Iron stains were removed successfully from ceramics, which soaked in oxalic acid for 60 hours. However, it is recommendable to soak in 0.25M oxalic acid for one to three hours because most iron stains were disappeared in 3 hours soaking. Citric acid is less effective than oxalic acid in removing iron stains because of heavy molecular weight and low acidity. Poultices (bentonite, sepiolite, activated carbon fiber and celite) with oxalic acid were applied on contaminated ceramics. After ten hours, iron stains on ceramics were removed successfully by poultice. Among them, bentonite and sepiolite have better application. Therefore, sepiolite with 0.25M oxalic acid was applied on the iron stains of whiteware and celadon from Ma Island, and then stains were removed. However, it is judged that the application methods can be varied according to the form and depth of contaminant. In addition, the residues of poultice on the ceramics will be considered for preventing contamination.

• Journal of Radiation Protection and Research
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• v.25 no.1
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• pp.11-19
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• 2000

The sensitivity analysis of input parameters for a dynamic food chain model DYNACON was conducted as a function of deposition date for the long-lived radionuclides $(^{137}Cs,\;^{90}Sr)$. Also, the influence of input parameters for the short and long-terms contamination of selected foodstuffs (cereals, leafy vegetables, milk) was investigated. The input parameters were sampled using the LHS technique, and their sensitivity indices represented as PRCC. The sensitivity index was strongly dependent on contamination period as well as deposition date. In case of deposition during the growing stages of plants, the input parameters associated with contamination by foliar absorption were relatively important in long-term contamination as well as short-term contamination. They were also important in short-term contamination in case of deposition during the non-growing stages. In long-term contamination, the influence of input parameters associated with foliar absorption decreased, while the influence of input parameters associated with root uptake increased. These phenomena were more remarkable in case of the deposition of non-growing stages than growing stages, and in case of $^{90}Sr$ deposition than $^{137}Cs$ deposition. In case of deposition during growing stages of pasture, the input parameters associated with the characteristics of cattle such as feed-milk transfer factor and daily intake rate of cattle were relatively important in contamination of milk.

• Journal of Radiation Protection and Research
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• v.39 no.2
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• pp.89-95
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• 2014

In potential accident consequence assessments for the licensing approval of LWRs, the ground deposition of radionuclides released into the environment is not allowed into the models, as recommended in the U. S. Nuclear Regulatory Commission's regulatory guide. Meanwhile, it is allowed into the assessment models for the licensing approval of PHWRs with consideration of more detailed physical processes of radionuclides in the atmosphere. Under these backgrounds, importance of exposure dose by ground deposition was quantitatively evaluated and comprehensively discussed. For potential accidental releases of $^{137}Cs$ and $^{131}I$, total exposure doses were more conservative in case of without consideration of ground deposition than in case of with its consideration. It was because of that the depletion of air concentration resulting from ground deposition is more influential in the contribution to total exposure doses than additional doses from contaminated ground. The exposure doses by the inhalation of contaminated air showed the contribution of more than 90% in total exposure doses, depending on atmospheric stability, release period of radionuclides and distance from a release point. The exposure doses from contaminated ground showed less than 10% at most in contribution of total exposure doses. The ratios of total exposure doses in case of with consideration of deposition to without its consideration for $^{131}I$ were distinct than those for $^{137}Cs$. As the atmosphere is more stable, release duration of radionuclides is longer, distance from a release point is longer, it was more distinct.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.599-609
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• 1997

The phase behavior and dynamics of colloid suspensions and the resulting structures and properties of powder compacts were examined by a computer experimental method for cooperative packing processes. A wide range of properties and process conditions such as arbitrary particle size, medium densities, field strength, and temperature could be examined using the Peclet number (Pe). We demonstrated that an optimum range of Peclet number for the ordering of sediments was present and that the phenomena related to the ordering such as the onset of crystallization, the phase behavior, etc. strongly depend on process conditions. The present work appears to be useful to design the processing method of ceramic spherical submicron powders for the preparation of high-density green compacts.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.192-192
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• 2021

산지 사면에서 발생한 토석류는 지형변화에 큰 영향을 미치는 대표적인 자연재해이다. 특히, 집중호우로 인해 발생하는 산사태의 경우 단시간에 많은 토사가 붕괴되며, 이는 매우 빠른 속도로 유동하는 토석류로 발전할 수 있다. 이러한 토석류가 도심지역에서 발생할 경우 많은 인명 및 재산피해를 야기하며, 이와 같은 피해를 저감하기 위해선 토석류의 유동과 피해규모를 예측할 수 있는 수치모형을 통한 연구가 필수적으로 이루어져야한다. 유동 및 퇴적지역의 피해규모를 크게 증가시킬 수 있는 침식-연행작용에 대한 연구는 최근에 활발히 이루어지고 있다. 수치모형으로 분석된 피해범위와 규모를 정밀하게 산정하기 위해선 침적과정에 대한 구현·해석이 필요하나 국내·외적으로 토석류 침적에 대한 연구는 미비한인 실정이다. 이에 본 연구는 침적을 고려하는 침식-연행작용 모형을 개발하여 토석류의 유동 및 퇴적과정을 자연현상에 가깝게 묘사하고자 하였다. 해당 모형은 2011년 우면산 일대에서 발생한 일련의 토석류를 대상으로 검증하고자하며, 연구지역의 지형 및 붕괴지점 자료는 토석류 발생 전·후 DEMs(Digital Elevation Models)을 이용하여 구축하였다. 현장에서 관측된 피해 범위, 총퇴적량, 특정 지점에서의 최대 피해 높이와 첨두속도 등은 실측자료로 활용하여 모형의 결과와 비교·분석하였으며 이를 통해 모형의 성능을 검증하고자 하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.385-387
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• 2021

Marine deposition waste threatens the book ecosystem and causes a decrease in catch due to ghost fishing, causing damage of about 370 billion won per year. In order to collect this, a current status survey is conducted using two-way ultrasonic detectors, diving, and lifting frames. However, the scope of the investigation is small to investigate a lot of sedimentary waste, and there is a possibility of causing casualties. This paper deals with the implementation of a high-accuracy marine deposition detection AI model by learning the coastal sediment image data of AI-Hub using the YOLOv5 algorithm suitable for real-time object detection.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.355-356
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• 1999

대기오염물질의 침적에 의해 호소나 연안해수의 조성이 변화하여 수서 생태계에 영향을 미칠 가능성에 대해서는 여러 논의가 있었다. 특히 질소화합물의 대기로부터의 유입에 의한 부영양화는 적조 등의 현상을 일으켜, 연안 생태계에 큰 영향을 미칠 수 있다. 따라서, 연안에서 침적되는 대기오염물질의 양을 추산하기 위해 에어로솔상의 이온성분을 측정하는 것은 침적 현상이해에 매우 중요하다.(중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.109-111
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• 2000

지금까지 대기침적량의 산정에는 크게 대기중의 오염물질 농도와 침적속도를 이용하여 추정하는 방법 (atmospheric flux methods)과 대리표면을 이용하여 건성침적량을 직접 측정하는 표면분석 방법(surface analysis methods)이 주로 이용되고 있다. 전자는 대기중 오염물질 농도를 관측ㆍ분석함으로써 eddy correlation, aerodynamic gradient methods 등의 미기상학적인 방법이 여기에 해당되며 균일하지 못한 표면이나 중력침강이 주가되는 조대입자에 대해 사용이 제한되는 단점이 있다. 이에 반해 대체표면을 사용하는 방법은 일반적으로 시료채취 및 분석과정에 있어서 통제가 용이하기 때문에 현재 광범위하게 널리 사용되고 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.94-96
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• 2000

Polycyclic aromatic hydrocarbons(다환방향족 탄화수소류: 이하 PAHs)는 여러 가지 오염원에서 배출되어 환경계에서 이동하는 중요한 화합물질 그룹중의 하나이다. 대부분의 PAHs는 발암물질이라고 의심이 가는 물질로써 여러 가지 형태의 배열로 연결되어 있는 두개 혹은 그 이상의 방향족 고리로 구성되어 있다 PAHs의 대기에서의 침적은 가스상과 입자상 물질의 비나 눈에 의한 제거, 입자상 물질의 건식침적 및 가스상 물질의 대기-수체간 교환에 의하여 이루어진다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.113-114
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• 2001

산업화ㆍ도시화에 따라 인구 증가, 교통량 증가 및 도시 구조물의 증가 등으로 인하여 도시의 대기오염과 열섬 현상 등이 날로 심각한 사회문제로 제기되고 있다. 일반적으로 대기 중에 부유하는 오염물질들은 광화학 반응을 통하여 2차 오염물질이 생성되기도 하고, 기상인자에 의하여 확산 또는 수송되어 대기오염도가 감소하거나, 중력에 의하여 지표 부근에 침적되어 제거된다. 특히, 건성 및 습성 침적되는 강하먼지는 단위 지역의 대기오염을 파악하거나, 타 지역과의 비교에 지표로 활용되고 있다. (중략)