• 방사성폐기물학회지
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• 제4권2호
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• pp.153-159
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• 2006

우라늄 변환시설 가동 중 발생하여 라군(lagoon)에 저장중인 방사성 슬러지 폐기물에 대한 처리는 시설 해체과정에서 매우 중요한 업무 중 하나이다. 슬러지 구성성분 중 다량을 차지하는 질산암모늄의 폭발 위험성 등으로 인해 미생물을 이용한 질산염의 분해는 질산염을 안정적으로 처리할 수 있는 효과적인 방법이라 할 수 있다. 본 연구에서는 라군 슬러지의 약 60 wt%를 차지하는 질산염을 혐기성 균주의 하나인 Pseudomonas halodenidificans를 이용하여 탈질하기위한 공정 변수에 대한 영향을 평가하였다. 온도, 질산염 농도, 전자공여체의 영향, C/N 비율, 초기 접종하는 균주의 비율, pH등의 공정변수에 대하여 실험한 이번 결과는 향후 연속식 공정 설계를 위한 기초 자료로 사용될 것이다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.62-66
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• 2002

The conventional floating zone(FZ) crystal and Czochralski(CZ) silicon crystal have resistivity variations longitudinally as well as radially The resistivity variations of the conventional FZ and CZ crystal are not conformed to requirement of dopant distribution for power devices and thyristors. These resistivity variations in conventional cystals limits the reverse breakdown voltage that could be achieved and forced designers of high power diodes and thyristors to compromise the desired current-voltage characteristics. So to produce high Power diodes and thyristors, Neutron Transmutation Doping(NTD) technique is the one method just because NTD silicon provides very homogeneous distribution of doping concentration. This procedure involves the nuclear transmutation of silicon to phosphorus by bombardment of neutron to the crystal according to the reaction $^{30}$ Si(n,${\gamma}$)longrightarrow$^{31}$ Silongrightarrow(2.6 hr)$^{31}$ P+$\beta$$^{[-10]}$ . The radioactive isotope $^{31}$ Si is formed by $^{31}$ Si capturing a neutron, which then decays into the stable $^{31}$ P isotope (i.e., the donor atom), whose distribution is not dependent on the crystal growth parameters. In this research, neutron was irradiated on FZ silicon wafers which had high resistivity(1000~2000 Ω cm), for 26 and 8.3hours for samples of HTS-1 and HTS-2, and 13, 3.2, 2.0 hours for samples of IP-1, IP-2 and IP-3, respectively, to compare resistivity changes due to time differences. The designed resistivities were approached, which were 2.l Ωcm for HTS-1, 7.21 Ω cm for HTS-2, 1.792cm for IP-1, 6.83 Ωcm for IP-2, 9.23 Ωcm for IP-3, respectively. Point defects were investigated with Deep Level Transient Spectroscopy(DLTS). Four different defects were observed at 80K, 125K, 230K, and above 300K.

• 대한핵의학회지
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• 제3권2호
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• pp.1-16
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• 1969

The double tracer study on erythrokinetics was carried out experimentally with radioactive iron ($^{59}Fe$) and chromium ($^{51}Cr$) in rabbits. The 0.1% canthalidin solution and 1% pot. perchlomate solution was given subcutaneously to 20 rabbits respectively. 3 and 6 days after injection, the blood chemistry, urine examination, ferrokinetics and apparent half survival time of RBC were ($^{51}Cr\;T\frac{1}{2}$)determined. Following were the results: 1) Red blood cell hematocrit and hemoglobin values were moderately reduced and B.U.N. and serum creatinine values were slight]y inercased in the canthalidin group, while B.U.N. and serum creatinine values were within normal limits in the pot. perchlomate group. Reticulocyte values were slight]y increased in the canthalidin group, while was normal range in the pot. perchlomate group. 2) Blood chemistry finding was not significant statistically in both experimental groups, but serum iron value was moderately reduced in both group. 3) Plasma volume was unchanged in both group, but red cell volume and whole blood volume were slightly reduced in both groups. 4) Results of ferrokinetics were as follows: i) The plasma iron disappearance rate was delayed in both groups. Plasma iron turnover rate, red cell iron utilization and red cell iron turnover rate were decreased in both groups, and then red cell iron turnover rate was more decreased than plasma iron turnover rate in both groups. Circulating red cell iron was slight]y increased in canthalidin group and red cell iron concentration was within normal range in both groups. ii) P.I.T.R.-R.C.I.T. value was moderately increased in the canthalidin group and slightly increased in the pot. perchlomate group. Reticulocyte index, red cell iron turnover index, plasma iron turnover index and effective erythropoiesis index were whole]y reduced in both groups. iii) The red cell life span was slightly shortened in the canthalidin group while was within normal range in pot. perchlomate group. The pathologic finding of renal biopsy of the canthalidin group shows a selective damage in glomerulus, while shows almost normal range or slight damage in tubules. And that of the pot. perchlomate group shows a selective damage in tubules with slight damage of glomerulus.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1177-1182
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• 2012

Protein kinase C (PKC) has been implicated in carcinogenesis and displays variable expression profiles during cancer progression. Studies of dietary phytochemicals on cancer signalling pathway regulation have been conducted to search for potent signalling regulatory agents. The present study was designed to evaluate any suppressive effect of maslinic acid on PKC expression in human B-lymphoblastoid cells (Raji cells), and to identify the PKC isoforms expressed. Effects of maslinic acid on PKC activity were determined using a PepTag$^{(R)}$ assay for non-radioactive detection of PKC. The highest expression in Raji cells was obtained at 20 nM PMA induced for 6 hours. Suppressive effects of maslinic acid were compared with those of four PKC inhibitors (H-7, rottlerin, sphingosine, staurosporine) and two triterpenes (oleanolic acid and ursolic acid). The $IC_{50}$ values achieved for maslinic acid, staurosporine, H-7, sphingosine, rottlerin, ursolic acid and oleanolic acid were 11.52, 0.011, 0.767, 2.45, 5.46, 27.93 and $39.29\;{\mu}M$, respectively. Four PKC isoforms, PKC ${\beta}I$, ${\beta}II$, ${\delta}$, and ${\zeta}$, were identified in Raji cells via western blotting. Maslinic acid suppressed the expression of PKC ${\beta}I$, ${\delta}$, and ${\zeta}$ in a concentration-dependent manner. These preliminary results suggest promising suppressive effects of maslinic acid on PKC activity in Raji cells. Maslinic acid could be a potent cancer chemopreventive agent that may be involved in regulating many downstream signalling pathways that are activated through PKC receptors.

• 한국환경보건학회지
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• 제24권2호
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• pp.126-133
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• 1998

Effects of B(a)P on preimplantation mouse embryos in vitro were studied. Preimplantation mouse embryos were exposed to a concentration of 0.3, 1, 3 and 10 $\mu$M B(a)P for 72 hrs. The toxicological effects of B(a)P were evaluated by morphological observation of embryos up to the blastocyst stage, and by measuring DNA, RNA and protein synthesis by radioactive precursor incorporation. At 1 $\mu$M B(a)P did not affect preimplantation development but interfered with hatching and ICM formation. Suppressing effect of ICM formation was dose dependent. At the eight cell stage, the developmental rate was decreased at above 3 $\mu$M of B(a)P. At the blastocyst stage, attachment and trophoblast outgrowth were diminished at the 10 $\mu$M of B(a)P and ICM formation was decreased at 1 $\mu$M of B(a)P. Inner cell number of blastocyst was decreased dose dependently. So, number of ICM was one of the most sensitive and toxicological end point. The RNA incorporation rate of 0.1 $\mu ^3$H-uridine was dosedependent and the protein incroporation of 0.5 $\mu Ci ^{35}$S-methionine showed a significant decrease after 48 hrs. But the DNA incorporation rate of methyl-$^3$H thymidine was not affected. Our results suggested that B(a)P did not affect the DNA replication but transcription was inhibited by dose dependent manner. There delay of development during the blastocyst stage was mainly due to the inhibition of RNA synthesis followed by protein synthesis.

• Journal of Radiation Protection and Research
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• 제24권1호
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• pp.9-15
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• 1999

칼슘을 함유한 방사성 환경시료 용액으로부터 스트론튬을 분리하기 위한 방법으로 함침형 액막을 제조하여 그 분리특성을 고찰하였다. 운반체로 사용된 DC18C6과 DNNS의 농도에 따라 금속이온 투과도와 스트론튬 선택도에 영향을 미쳤으며, 특히 0.1M DC18C6과 25mM DNNS을 함침시켜 제조한 액막의 경우에서 93.3%의 스트론튬 선택도를 얻을 수 있었다. 모의용액의 스트론튬에 대한 칼슘의 함량비가 1 : 25 - 1 : 50일 때 스트론튬 선택성이 90% 이상으로 나타났으며, 따라서 본 연구에서 제조한 액막은 스트론튬 측정을 위한 해수 환경시료의 전처리에 적용 가능할 것으로 생각된다.

• 한국대기환경학회지
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• 제24권5호
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• pp.538-550
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• 2008

Radon is an invisible, odorless, and radioactive gas. It is formed by the disintegration of radium, which is a decay product of uranium. Some amounts of radon gas and its products are present ubiquitously in the soil, water, and air. Particularly high radon levels occur in regions of high uranium content. Although radon is permeable into indoor environment not only through geological features (bed rock and permeability) but also through the construction materials and underground water, the radiation from the geological features is generally main exposure factor. So there can be a problem in a certain space such as the underground and/or relatively poor ventilation condition. In this study, a GIS technique was used in order to investigate spatial distribution of radon measured from sub- way stations of 1 thru 8 in Seoul, Korea in 1991, 1998, 2001, and 2006. Spatial analysis was applied to reproduce the radon distribution. We utilized spatial analysis techniques such as inverse distance weighted averaging (IDW) and kriging techniques which are widely used to relate between different spatial points. To validate the results from the analyses, the jackknife technique for an uncertainty test was performed. When the number of measuring sites was less than 100 and also when the number of omitted sites increased, the kriging technique was better than IDW. On the other hand, when the number of sites was over 100, IDW technique was better than kriging technique. Thus the selection of analytical tool was affected sensitives by the analysis based on the number of measuring sites.

• 방사성폐기물학회지
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• 제3권4호
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• pp.335-340
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• 2005

Single-pass flow-through (SPFW) 방법에 의한 유리고화체의 용해율 측정에서 정밀도를 구하기 위하여 연구소간 실험프로그램의 하나로서 붕규산유리고화체의 정용해율을 구하였는데, 이 SPFT 방법은 American Society for Testing and Materials (ASTM)에서 표준화를 위하여 작성되었다. 이를 위해 100/200 mesh 크기의 모의 저방사능 유리고화체 분말시료를 $70^{\circ}C$, 알곤 분위기에서 SPFT 방법으로 리튬 완충용액 (pH=10)을 이용하여 용해실험을 시도하였다. 얻어진 용출액 중 규소와 붕소의 농도에 따라 용해율의 변화를 구한 결과, 유리의 정용해율이 $2.7\times10^{-5}g{\cdot}m^{-2}{\cdot}s^-1$ 부근으로 나타났다.

• 방사성폐기물학회지
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• 제1권1호
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• pp.81-92
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• 2003

폐기물 용액의 pH 변화에 따른 고정층에서 우라늄 및 코발트 이온의 흡착거동을 다성분 흡착시스템으로 가정하여 이론적으로 예측하였다. 즉 pH 변화에 따라 존재 분율이 달라지는 각 이온 성분들이 상호 경쟁적으로 흡착한다는 가정 하에서, 평형실험에서 얻어진 결과와 우라늄 및 코발트 이온의 용액특성 (Solution chemistry)을 상호 결합하여 각 이온 성분들의 Langmuir 평형상수 값을 Ideal Adsorbed Solution Theory를 도입하여 구하였으며, 이상의 결과를 이용하여 고정층 파과곡선을 이론적으로 계산한 결과 pH 변화에 따른 흡착거동을 비교적 잘 예측할 수 있었다 따라서 본 연구에서 시도한 방법은 이온 농도와 pH가 높은 경우를 제외하고 pH 변화에 따라 용액 내에 이온의 형태가 다양하게 존재하는 흡착 시스템을 이론적으로 예측하는 데 비교적 유용하게 사용할 수 있을 것으로 판단된다.

• 분석과학
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• 제18권4호
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• pp.298-308
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• 2005

사용후핵연료시료 중에 함유된 탄소-l4와 트리튬을 회수 및 정량하였다. $CO_2$ 운반체($CaCO_3$)를 포함한 사용후핵연료시료를 $90^{\circ}C$에서 8M $HNO_3$ 용액으로 용해하면서 휘발된 $^{14}CO_2$를 1.5 M NaOH 용액을 포함한 포집관에 수집하였다. 용해 중 휘발되는 방사성 요오드는 Ag-silica gel 흡착체를 담은 포집 관으로 사전제거하였다. 핵연료 용해용액 중에 남아있는 트리튬(HTO)를 정량하기 위하여 양이온과 음이온 교환수지 혼합물 및 무기이온교환체를 이용한 뱃치 및 분리관법으로 용해용액을 탈이온화시켜 간섭이온을 제거하였다. 포집용액 중의 탄소-14와 탈이온화수 중의 트리튬을 액체섬광계수법으로 정량하였다.