• 한국물환경학회지
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• 제34권4호
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• pp.375-381
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• 2018

The monitoring of phytoplankton biomass and community structure is essential as a first step to control the harmful cyanobacterial blooms in freshwater systems, such as seen in rivers and lakes, due to the process of eutrophication and climate change. In order to quantify the biomass of phytoplankton with a wide range in size and shape, the measurement of cell biovolume along with cell density is required for a comprehensive review on this issue. However, most routine monitoring programs preserve the gathered phytoplankton samples before analysis using chemical additives, because of the constraint of time and the number of samples. The purpose of this study was to investigate the cell biovolume change characteristics of six cyanobacterial species, which are common bloom-causing cyanobacteria in the Nakdong River, after the preservation with Lugol's iodine solution. All species showed a statistically significant difference after the addition of Lugol's iodine solution compared to the live cell biovolume, and the cell biovolume decreased to the level of 34.0 ~ 56.3 % at maximum in each species after the preservation. The nonlinear regression models for determining the shrinkage ratio by a preservation period were derived by using the cell biovolume measured until 180 days preservation of each target species, and the equation to convert the cell biovolume measured after preservation for a certain period to the cell biovolume of viable cell was derived using that formula. The conversion equation derived from this study can be used to estimate the actual cell biovolume in the natural environment at the time of sampling, by using the measured biovolume after the preservation in the phytoplankton monitoring. Moreover this is expected to contribute to the final interpretation of the water quality and aquatic ecosystem impacts due to the cyanobacterial blooms.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.279-286
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• 2020

In this article, we develop a reactive distillation (RD) column configuration for the production of hydrogen. This RD column is in the HI decomposition section of the sulphur - iodine (SI) thermochemical cycle, in which HI decomposition and H₂ separation take place simultaneously. The section plays a major role in high hydrogen production efficiency (that depends on reaction conversion and separation efficiency) of the SI cycle. In the column simulation, the rigorous thermodynamic phase equilibrium and reaction kinetic model are used. The tuning parameters involved in phase equilibrium model are dependent on interactive components and system temperature. For kinetic model, parameter values are adopted from the Aspen flowsheet simulator. Interestingly, there is no side reaction (e.g., solvation reaction, electrolyte decomposition and polyiodide formation) considered aiming to make the proposed model simple that leads to a challenging prediction. The process parameters are determined on the basis of optimal hydrogen production as reflux ratio = 0.87, total number of stages = 19 and feeding point at 8th stage. With this, the column operates at a reasonably low pressure (i.e., 8 bar) and produces hydrogen in the distillate with a desired composition (H₂ = 9.18 mol%, H₂O = 88.27 mol% and HI = 2.54 mol%). Finally, the results are compared with other model simulations. It is observed that the proposed scheme leads to consume a reasonably low energy requirement of 327 MJ/kmol of H₂.

• 대한화학회지
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• 제37권10호
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• pp.855-860
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• 1993

SDS(sodium dodecyl sulfate) 존재하에서 NP-40EO[nonylphenol-(ethylene oxide)40]와 요오드와의 상호작용에 따른 $Ca^{2+}$의 영향을 UV-visible spectrophotometer를 이용하여 수용액 중에서 조사하였다. SDS 부재시보다 상호작용 피크의 흡광도는 줄어들었으며, CMC 이상에서 $Ca^{2+}$ 첨가에 따른 상호작용 피크의 강도는 크게 증가하였다. 상호작용 피크의 감소는 SDS 삽입에 따른 혼합미셀 단위 표면적당 요오드와 상호작용할 수 있는 EO 수의 감소에 기인하며, 상호작용 피크 강도의 증가는 $Ca^{2+}$ 존재하에서 미셀 구조가 더욱 조밀해진데 따른 전자주게-받게 겹침 증가로 불 수 있다. 이러한 현상들은 수용액 중에서 상대적으로 자유로운 배향을 갖는 선형 EO 사슬이 유사 크라운 에테르 구조를 형성하여 $Ca^{2+}$ 이온과 착물을 형성할 수 있는 가능성을 보여준다.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1738-1742
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• 2005

In this study a novel triiodide ion-selective electrode based on a charge transfer complex of iodine and Bis(2-hydroxyacetophenone)butane-2,3-dihydrazone (ICT), as a membrane carrier was prepared. The electrode has a linear dynamic range between 1.0 ${\times}$ $10^{-2}$ and 5.0 ${\times}$ $10^{-7}$ M, with a Nernstian slope of 58. 99 ${\pm}$ 0.3 mV $decade^{-1}$ and detection limit of 3.0 ${\times}$ $10 ^{-7}$ M. The potentiometric response of the proposed sensor is independent of the pH of the solution in the pH range of 3.0-10.0. The electrode possesses the advantages of short conditioning time, fast response time, and especially, very good selectivity over a large number of common organic and inorganic anions. The electrode can be used for at least 6 months without any considerable divergences in the potentials. It was used as an indicator electrode in potentiometric titration of triiodide ion with thiosulfate.

• 한국환경과학회지
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• 제10권5호
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• pp.373-380
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• 2001

In recent years, the demand of activated carbon has been increasing steadily because of the environmental problems. Among them waste and water treatment and removal of poisonous gas were invorved. Therefore, in this study, activated carbon was made from the waste chinese cabbage and measured the iodine adsorption ability, carbonization yield, and activation yield of the produced activated carbon. The result showed that the carbonization yield was decreased when carbonization temperature was increaed and that the optimal carbonization temperature was $600{\circ}C$. The optimal concentration of NaOH for removing ash in the raw sample was 1~2N. The range of iodine adsorption number of activated carbon using chinese cabbage at $600{\circ}C$. carbonization was 610.82mg/g to 1019.58mg/g. The activation result of carbonization sample showed that the optimal activation condition was the carbonization at $400\circ}C$ and the activation at$700{\circ}C$. So the production of activated carbon using chinese cabbage was possible in the aspect of reuse of resource and decrease of environmental pollution compared to the commercial activated carbon.

• Applied Biological Chemistry
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• 제33권1호
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• pp.39-42
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• 1990

동부 전분의 아밀로오스 특성을 연구하였다. 동부 아밀로오스의 함량은 25.1 %였으며 iodine binding capacity는 20.2 %였다. 동부 아밀로오스의 ${\beta}-amylolysis$ limit는 82.3 %였고, 고유점도는 204ml/g이고 중합도는 1,510 glucose units였다. 겔 크로마토그래피에 의한 아밀로오스의 분자량 분포는 $1{\times}10^4$(0.7 %), $1{\times}10^4{\sim}4{\times}10^4$(4.1 %), $4{\times}10^4{\sim}5{\times}10^5$(44.6 %), $5{\times}10^5{\sim}4{\times}10^7$(49.6%)였고, 동부 아밀로오스와 요오드의 결합에 따른 최대 흡수 파장은 $615{\sim}645\;nm$의 범위였다.

• 한국방사선학회논문지
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• 제6권5호
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• pp.373-381
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• 2012

방사성옥소를 이용한 갑상선 암의 치료는 지난 수 십년 동안 사용되어 왔으며 많은 치료효과를 보이면서 앞으로 지속적으로 사용되어 질 전망이고 현재 우리나라의 옥소치료병실 수는 2010년 기준 124개의 치료병실이 운영되고 있으나 아직도 부족한 실정이다. 그래서 많은 병원들이 치료병실을 개설하고 있으나 중요한건 치료병실의 수적 증가보단 현재 치료병실의 올바른 관리가 선행되어야 한다는 것이다. 따라서 병실증설에 대한 논의에 앞서 현재 적용되고 있는 치료병실의 안전관리 기준과 일부 대학병원에서 기준으로 삼고 있는 안전관리기준을 조사하여 얼마나 잘 지켜지고 있는지, 치료병실의 이용에 따른 전반적인 안전관리실태여부를 조사하여 고찰 하였다.

• 핵의학기술
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• 제22권1호
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• pp.28-34
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• 2018

국내 의료기관의 방사성옥소(I-131) 사용과 관련하여 배수 중 방사능농도가 원자력안전법의 허용치를 초과한 사례가 발견되어, 원인 분석 및 배수 중 방사능농도 분석을 통해 주변 환경 공공수역에 대한 관계를 평가하여 유용성에 대해 알아보고자 한다. 2014년 11월 1일부터 2015년 4월 30일까지 6개월에 걸쳐 국내 20개 병원을 대상으로 하였다. 장비는 HpGe 감마선 분광 측정기(Canberra DSA1000)를 사용하였으며, 분석방법으로는 GENIE-2000 Analysis을 이용하여 방사성옥소의 배수 중 방사능농도를 측정하여 비교 분석하였다. 연구 결과, 7개 기관이 I-131 배수 중 배출관리 기준을 초과하였음을 확인하였으며, 20개 병원의 평균 배수 중 방사능 농도는 $4.21E+4 Bq/m^3$로 나타났다. 방사능농도가 높은 병원의 특징으로는 I-131을 이용한 다수의 외래환자 진료 건수, 외래전용 화장실의 부재로 확인되었다. I-131 whole body scan 전 반드시 소변을 보게 하는 과정에서 체내에 잔류한 I-131이 배출되는 것으로 판단된다. 공공수역 내 배수 중 방사능 농도가 초과 검출되는 원인으로는 진료용 방사성옥소라 판단되며, 저용량 투여환자 외래전용 화장실 설치와 안전관리 지침서 제공 및 교육 강화의 중요성을 확인할 수 있었다. 또한 배수 중 배출관리기준과 관련하여 법적, 제도적 관리 체계 구축이 필요할 것으로 사료된다.

• 한국콘텐츠학회논문지
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• 제11권1호
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• pp.236-244
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• 2011

성능이 저하된 IVR 장치의 지속적 사용은 환자 및 시술자의 방사선 피폭을 증가시킬 뿐 아니라, 잘못된 영상정보를 제공함으로써 환자에게 심각한 영향을 끼칠 수 있다. 따라서 이번 연구에서는 IVR장치의 성능평가를 위한 적절한 시험방법 및 검사기준을 마련하고자 하였다. IVR장치의 국내현황 및 규격을 조사하였으며, 표준팬텀을 이용하여 국내 IVR장치의 성능을 현장 측정함으로써, 국내 실정에 맞는 적절한 IVR 장치의 화질 및 성능평가 기준을 설정하였다. 장치의 기본적 성능에 관한 검사를 위해 관전압시험, 관전류 시험, 반가층 시험을 실시하며, NEMA stndard XR-21 Phantom을 표준팬텀으로 사용하여 화질 및 선량 평가를 하도록 하였다. 표준팬텀을 이용한 검사항목은 image-field geometry, spatial resolution, low-contrast iodine detectability, wire resolution, phantom entrance dose이다. 또한 매일, 매주, 1개월, 3개월, 6개월 및 1년 주기의 평가항목을 설정하였다. 장치의 성능기준은 진단용방사선안전관리 규정을 준용하여 kVp시험은 평균오차 ${\pm}10%$, mA시험은 평균오차 ${\pm}15%$, 반가층시험은 80kVp에서 최소 2.3mmAl으로 설정하였다. 표준팬텀의 검사기준은 image-field geometry에서 최소 acceptable이 나와야 하며, spatial resolution은 Image Intensifier 나 detector 크기기준으로 34-40cm은 0.8 lp/mm, 28-33cm은 1.0lp/mm, 22-27cm은 1.2 lp/mm이상이 나와야 한다. low contrast iodine detectability는 최소농도 200mg/cc 이상 보여야 하며, phantom entrance dose는 10R/min을 초과해서는 안 된다. Wire resolution은 정지 상태에서 최소 0.012인치까지 보여야 하며, 움직일 때 최소 0.022인치까지 보여야 한다.

• 핵의학기술
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• 제17권1호
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• pp.3-6
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• 2013

Purpose: The treatment of thyroid cancer patients was continuously increased. According to the increment of thyroid cancer patients, the establishment of iodine therapy site was also increased in each hospital. This treatment involves the administration of radioactive iodine, which will be given in the form of a capsule. Therefore, protections and managements for radioactive source pollution and radiation exposure should be necessary for radiation safety. Among the many problems, the problem of disposing the radioactive wastes was occurred. In this study, The date for self-disposal for radioactive wastes, which were contaminated in clothes, bedclothes and trash, were calculated. Materials and Methods: The number of iodine therapy ward was 15 in Korea Institute of Radiological Medical and Sciences. Recently, 8 therapy wards were operated for iodine therapy patients and others were on standby for emergency treatment ward of any radiation accidents. Radioactive wastes, which were occurred in therapy ward, were clothes, bedclothes, bath cover for patients washing water and food and drink which was leftover by patients. Each sample was hold into the marinelli beaker (clothes, bedclothes, bath covers) and 90 ml beaker (food, drink, and washing water). The activities of collected samples were measured by HpGe MCA device (Multi Channel Analysis, CANBERRA, USA) Results: The storage period for the each kind of radioactive wastes was calculated by equation of storage periods based on the measurement outcomes. The average storage period was 60 days for the case of clothes, and the maximum storage period was 93 days for patient bottoms. The average storage period and the maximum storage period for the trash were 69 days and 97 days, respectively. The leftover foods and drinks had short storage period (the average storage period was 25 days and maximum storage period was 39 days), compared with other wastes. Conclusion: The proper storage period for disposing the radioactive waste (clothes, bedclothes and bath cover) was 100 days by the regulation on self-disposal of radioactive waste. In addition, the storage period for disposing the liquid radioactive waste was 120 days. The current regulation for radioactive waste self-disposing was not suitable for the circumstances of each radioactive therapy facility. Therefore, it was necessary to reduce the leftover food and drinks by adequate table setting for patients, and improve the process and regulation for disposing the short-half life radioactive wastes.