• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1324-1329
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• 2018

This study presents a practical application of complementary safety indicators, which can be applied in a safety assessment of a radioactive waste repository by excluding a biosphere simulation and comparing the artificial radiation originating from the repository with the background natural radiation. Complementary safety indicators (radiotoxicity flux from geosphere and radiotoxicity concentration in seawater) were applied in the safety assessment of a rock-cavern type low and intermediate level radioactive waste (LILW) repository in the Republic of Korea. The natural radionuclide ($^{40}K$, $^{226,228}Ra$, $^{232}Th$, and $^{234,235,238}U$) concentrations in the groundwater and seawater at the Gyeongju LILW repository site were measured. Based on the analyzed concentrations of natural radionuclides, the levels of natural radiation were determined to be $8.6{\times}10^{-5}$ - $8.0{\times}10^{-4}Sv/m^2/yr$ and $6.95{\times}10^{-5}Sv/m^3$ for radiotoxicity flux from the geosphere and radiotoxicity concentration in seawater, respectively. From simulation results obtained using a Goldsim-based safety assessment model, it was determined that the radiotoxicity of radionuclides released from the repository is lower than that of the natural radionuclides inherently present in the natural waters. The applicability of the complementary safety indicators to the safety case was discussed with regard to reduction of the uncertainty associated with biosphere simulations, and communication with the public.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2230-2243
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• 2022

The tin tailing processing industry in Malaysia has operated with minimal regard and awareness for material management and working environment safety, impacting the environment and workers in aspects of radiation and heavy metal exposure. RIA was conducted where environmental samples were analyzed, revealing concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K between the range of 0.1-10.0, 0.0-25.7, and 0.1-5.8 Bq/g respectively, resulting in the AED exceeding UNCEAR recommended value and regulation limit enforced by AELB (1 mSv/y). Ra_eq calculated indicates that samples collected pose a significant threat to human health from gamma-ray exposure. Assessment of heavy metal content via pollution indices of soil and sediment showed significant contamination and enrichment from processing activities conducted. As and Fe were two of the highest metals exposed both via soil ingestion with an average of 4.6 × 10^-3 mg/kg-day and 1.4 × 10^-4 mg/kg-day, and dermal contact with an average of 5.6 × 10^-4 mg/kg-day and 6.0 × 10^-4. mg/kg-day respectively. Exposure via accidental ingestion of soil and sediment could potentially cause adverse non-carcinogenic and carcinogenic health effect towards workers in the industry. Correlation analysis indicates the presence of a relationship between the concentration of NORM and trace elements.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1431-1438
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• 2022

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 93, 77, 92 and 938 Bq kg^-1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y^-1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30×10^-3, 4.26×10^-3, 0.62×10^-3, and 25.61×10^-3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4114-4121
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• 2021

The Rooppur Nuclear Power Plant (RNPP), the first nuclear power plant in Bangladesh with a capacity of 2.4 GWe, is under construction on the bank of the river Padma, at Rooppur in Bangladesh. Measurement of background radioactivity in the natural environment adjacent to RNPP finds great importance for future perspectives. Soil and sediment samples collected from upstream and downstream positions of the Padma River (adjacent to RNPP) were collected and analyzed by HPGe gamma-ray spectrometry for primordial radionuclides. The average activity concentrations (in Bqkg^-1) of ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides in soil samples were found to be 44.99 ± 3.89, 66.28 ± 6.55 and 553 ± 82.17 respectively. Respective values in sediment samples were found to be 44.59 ± 4.58, 67.64 ± 7.93, 782 ± 108. Relevant radiation hazard indices and dosimetric parameters were calculated and compared with the world average data recommended by US-EPA. Analytical results show non-negligible radiation hazards to the surrounding populace. Measured data will be useful to monitor any change of background radioactivity in the surrounding environment of RNPP following its operation for the generation of nuclear energy.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제25권3호
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• pp.213-232
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• 2022

분수 학습에서 수직선 모델의 중요성에 따라, 본 연구에서는 초등학교 4학년 학생들의 수직선에서의 분수 개념 및 분수의 덧셈과 뺄셈에 대한 이해가 어느 정도인지 살펴보았다. 수직선 검사 도구는 분수 나타내기, 분수의 크기 비교, 분수의 덧셈 및 뺄셈과 관련된 문항으로 구성되었으며 구조화된 수직선과 반구조화된 수직선을 제시하였다. 연구 결과, 전반적으로 정답률이 높지 않았으며, 정답보다 오답의 반응이 높게 드러난 문항들도 있었다. 또한 구조화된 수직선에 비하여 반구조화된 수직선이 제시되는 문항에서의 정답률이 낮게 드러났으며, 다양한 오답 반응을 확인할 수 있었다. 본 연구의 결과를 바탕으로 초등학생들의 분수 이해 및 수직선 이해를 위한 교수·학습 방향에 관한 시사점을 논의하였다.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4253-4264
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• 2022

Since the implementation of the phosphate project in Bled El-Hadba (BEH) deposit, western region of Tébessa, no detailed study has been conducted to assess the natural radioactivity distribution and the associated radiological risk parameter for this open-pit mine. For the sake of determining a credible premining reference database for the region of interest, 21 samples were collected from different geological layers of the above-mentioned deposit. Gamma Spectrometry was applied for measuring radioactivity using a high resolution HPGe semiconductor detector. The obtained activity results have shown a significant broad variation in the radioactive contents for the different phosphate samples. The total average concentrations (in Bq·kg^-1) for ²²⁶Ra, ²³⁸U, ²³⁵U, ²³²Th and ⁴⁰K computed for the different type of phosphate layers were found to be 570 ± 169, 788 ± 280, 52 ± 18, 66 ± 6 and 81 ± 18 respectively. The mean activity concentrations of the measured radionuclides were compared to other regional and worldwide deposits. The ratios between the detected radioisotopes have been calculated for spatial distribution of natural radionuclides in the study area. Based on the aforementioned activity concentrations, the corresponding radiation hazard parameters were assessed. Correlations between the obtained parameters were drawn and a multivariate statistical analysis (Pearson Correlation, Cluster and Factor analysis) was carried out in order to identify the existing relationships.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권2호
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• pp.217-232
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• 2000

The author studied on the 128 cases of benign odontogenic tumors which had been diagnosed with biopsy during the period of Jan. 1989 to Dec. 1998 at the Kyungpook National University Hospital, Yeungnam University Medical Center, Keimyung University Dongsan Medical Center, and Taegu Catholic Medical Center. This study contained the clinicostatistical analysis of the frequency in relation to sex, age, locations, chief complaints, duration, radiographic findings, recurrence, teeth, and treatment methods. The results were as follow : 1. Of a total of 128 benign odontogenic tumors, ameloblastomas(57 cases; 44.5%) and odontomas (44 cases ; 34.4%) mostly occupied. The other types of lesions were 8 calcifying odontogenic cysts, 7 benign cementoblastomas, 4 myxomas, 3 adenomatoid odontogenic tumors, 2 calcifying epithelial odontogenic tumors, 2 ameloblastic fibro-odontomas, and 1 odontogenic fibroma. 2. In age and sex distribution, benign odontogenic tumors occured slightly more often in males(53.9%) than females(46.1%) and the majority of cases(79.7%) were found during 2nd, 3rd, and 4th decade. 3. There was a predilection for mandibular lesions(mandible-maxilla ratio, 2.6 : 1). 4. The most common chief complaint was swelling(29.7%) and in respect to duration, the cases less than 1 year(50.0%) mainly appeared. 5. There were 7 cases(13.0%) of recurrence on ameloblastoma and there was no recurrence in the others. 6. In Ameloblastoma It commonly occured during 3rd and 4th decade(59.6%) and mean age was 30.2 years. The majority of cases were occurred in mandible(96.5%) , especially mandibular molar and angle area(71.9%). The most common chief complaint was swelling(47.4%) and in respect to duration, the cases less than 1 year(52.6%) mainly appeared. In relation to teeth, there were resorption of root(52.6%), displacement of teeth(31.6%), and in relation to impacted teeth(43.9%). There was higher recurrence rate in the cases by conservative treatment(14.7%) than radical treatment(10.0%). As regards radiographic findings, conservative treatments were prevalent in the cases of unilocular type(85.7%) as compared with multilocular type(48.5%). and there was higherrecurrence rate in the cases of multilocular type(18.2%) than unilocular type(4.8%). As regards the type of treatment in relation to age, conservative treatments were prevalent in patients younger than 20 years of age. 7. In Odontomas It commonly occured during 2nd decade(50.0%) and in maxillary anterior teeth(40.9%). The most common chief complaint was delayed retention and permanent impaction of teeth(72.7%), and most frequently associated with impacted teeth(79.5%).

• 한국식품조리과학회지
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• 제14권3호
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• pp.232-240
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• 1998

본 연구에서는 부추김치를 담글 때 최적의 들깨가루 첨가량을 찾기 위한 것으로 부추 무게의 0, 1, 2, 3, 5%의 들깨가루를 첨가하여 부추김치로 담그고, 담근 즉시 1$0^{\circ}C$에서 45일 동안 발효숙성 시키면서 이화학적, 미생물학적 및 관능적 특성을 알아보았는데 결과는 다음과 같다. pH와 총산도는 발효숙성 초기에 처리구간에 큰 변화가 없었다. 발효숙성 8일째까지는 들깨가루를 첨가한 구보다 첨가하지 않은 처리구의 발효숙성이 빨리 진행되어 높은 총산도를 나타내었으나, 발효숙성 25일 이후에는 오히려 들깨가루를 첨가한 처리구의 발효숙성이 빠르게 진행되었다. 총 비타민 C 함량은 발효숙성 8일째까지 거의 비슷한 함량을 보이다가 발효숙성 13일에 모든 처리구에서 크게 감소하였는데 특히 들깨가루를 첨가하지 않은 처리구와 들깨가루 1% 첨가구가 다른 처리구에 비하여 적은 총 비타민 C함량을 나타내었다. 발효숙성 40일에는 들깨가루 5% 첨가구가 가장 많았으며, 들깨가루를 첨가하지 않은 처리구가 가장 적게 나타났다. 젖산균 수는 발효숙성이 진행되면서 서서히 증가하였는데, 발효숙성 8일과 13일에 모든 처리구에서 크게 증가하였고, 들깨가루 2% 첨가구가 발효숙성 35일 이후부터 45일까지 다른 처리구에 비하여 많은 젖산균 수를 유지하였다. 관능평가 결과 발효숙성 초기인 발효숙성 2일에는 들깨가루 3%와 5% 첨가구를 선호하여 들깨가루의 첨가량이 많은 경우에는 부추김치가 덜 익은 상태에서 높은 기호도를 보였음을 알 수 있었으며, 발효숙성 45일까지 꾸준히 관능적 특성에서 우수한 것은 들깨가루 2% 첨가구였다. 이상의 결과를 종합해 볼 때 들깨가루는 발효숙성 초기에는 부추김치의 발효숙성을 억제하나, 발효숙성 말기에는 오히려 촉진하는 것으로 나타났으며, 들깨가루를 첨가하여 부추김치를 담글 때에는 들깨가루를 2% 첨가하는 것이 바람직할 것으로 생각된다.

• 한국초지조사료학회지
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• 제43권4호
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• pp.232-239
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• 2023

본 연구에서는 새로운 사료작물로서 국내 재래종 단수수의 반추 동물용 사료가치를 평가하기 위하여 무안재래종(국립식량과학원 바이오에너지작물연구소)을 공시하여 실험을 실시하였다. 단수수 재배는 유박비료를 정량 처리한 권장량구(RD), 권장량의 2배 처리구(Double RD) 및 무처리구(Con)를 두어 상지대학교 (강원도 원주시)에서 2021년 5월부터 10월까지 재배하였다. 단수수 모종을 포장에 이식 후 일주일 간격으로 12주간 초장 및 분지수를 조사하였고, 영양 성분, 당도 및 반추위 in vitro 소화율을 7, 9 및 11주에 측정하였다. 단수수는 초기에는 완만한 성장을 하다가 6~7 주차에 성장이 가장 빨랐고, 이후에는 정체를 나타내었다. 7주차 초장은 권장량 2배구가(295.00 ± 18.92cm), 권장량(273.33 ± 18.04cm) 및 무처리(229.17 ± 16.34cm) 순으로 큰 차이를 보였다(p<0.05). 조단백질은 7 및 9주차에 권장량 2배구(8.91 ± 0.11%, 5.74 ± 0.22%)가 다른 실험구보다 높은 수준을 나타내었고(p<0.05), 조지방은 9주차에는 권장량 2배구(1.38 ± 0.10%)가 다른 실험구보다 높았다(p<0.05). ADF는 7, 9 및 11주차에 권장량 2배구가 각각 36.14 ± 0.04, 25.48 ± 0.74 및 23.74 ± 0.59%로 가장 높게 나타났으며(p<0.05), NDF도 권장량 2배구가 7 및 9주차(47.55 ± 0.34 및 43.78 ± 0.27%)로 가장 높았다(p<0.05). 농가에서 재배한 옥수수(광평옥) 및 수단그라스 교잡종(그린스타)과 비교하였을 때 조단백질 함량은 단수수가 낮았고(p<0.05), 조지방 함량은 단수수가 옥수수에 비하여 높게 나타났다(p<0.05). 그리고 조섬유 함량, ADF 및 NDF는 단수수가 옥수수 및 수단그라스에 비하여 높았다(p<0.05). 단수수의 당도는 9 및 11주차에는 무처리구(6.13 ± 0.21 및 7.63 ± 0.21 brix) 및 권장량구(6.17 ± 0.12 및 7.27 ± 0.12 brix)가 권장량 2배구(4.07 ± 0.12 및 4.67 ± 0.06 brix)보다 높게 나타났고(p<0.05), 농가 재배 옥수수 및 수단그라스 교잡종보다 높게 나타났다(p<0.05). 반추위 in situ 소화율은 9주차 및 11주차에서 30.73~38.13% 수준이었으며, 농가 재배 옥수수 및 수단그라스 교잡종보다 높았다(p<0.05). 따라서 이상의 연구 결과를 볼 때 재래종 단수수는 조사료 작물로서 충분한 가치를 보유하고 있고, 초장이 273.33~332.50cm(9주차)일 때 사료작물로서 생산량, 소화율 및 영양가 등 양호할 것으로 사료된다. 또한 우수한 당도는 조사료로써 활용 측면에서 큰 장점으로 작용할 것이다.

• 한국식품위생안전성학회지
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• 제3권4호
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• pp.225-232
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• 1988

김치 저장기간 연장 목적으로 숙성된 김치에 1, 3, 5, kGy 의 감마선을 조사하고 $5^{\circ}C$에 저장하면서 미생물 생육, 이화학적 특성, 관능적 기호성 시험을 수행한 결과는다음과 같다. 1. 미생물 생육시험에서 호기성 세균은 저장 초기에 증가하나 젖산균의 증식과 함께 감소하는 경향이며, 방사선 조사에 의해 호기성 세균과 젖산균이 1~3log cycles 정도 감균되었다. 3kGy 조사구는 저장 90일에도 젖산균 수가 $1.3{\times}10^{8}/ml$ 정도로 낮았다. 대장균군과 곰팡이는 $2.0{\times}10^{4}/ml과\;5.4{\times}10^{2}/ml$ 정도 오염되었으나 3kGy 이상 조사로서 완전 사멸되었고, 비조 사구와 1kGy 조사구도 저장 20일 이후부터는 생육이 없었다. 효모는 $3.5{\times}10^{3}/ml$ 이든 것이 비조사구는 저장 90일에 $5.6{\times}10^{4}/ml$로 증식되었고 3kGy 조사구는 저장 90일에도 $6.5{\times}10^{2}/ml$로 낮았다. 2. 이화학적 특성변화에서 비조사구는 저장 45일에 pH, 산도, 휘발성 산이 각각 4.0, 0.7%와 0.066%였으나, 3kGy 조사구는 저장 90일에도 pH가 4.2, 산도가 0.59%, 휘발성 산이 0.06% 정도로 낮았다. 환원당을 모든 시험구에서 전 저장기간을 통해 산도의 증가와 반비례적으로 감소하였으나 방사선 조사구는 그 변화가 적었다. 조직 변화에서는 저장 기간의 경과와 함께 3kGy 조사구가 가장 우수하였다. 3. 관능검사에 의한 ralcl의 종합적 품질평가에서 3kGy 조사구는 비조사구에 비해 2개월 이상의 저장기간을 연장할 수 있었다.