• 분석과학
• /
• 제13권2호
• /
• pp.179-188
• /
• 2000

대기환경시료인 도시분진시료와 인공적으로 준비한 휠터상 도시분진시료중의 미량원소를 중성자방사화분석법을 사용하여 비파괴 분석하였다. 분석정도관리를 위하여 미국 표준기술원의 인증표준시료 (Urban Dust, NIST SRM 1648)를 이용하였다. 37종의 검출된 원소의 상대오차와 상대 표준편차를 계산하였으며 각각 10%와 15%이내이었다. 도시분진시료로부터 29종의 원소, 휠터상 도시분진시료로부터 21종의 원소를 정량하였다. 측정결과의 신뢰도 및 숙련도 평가를 위하여, 중성자방사화분석법, 하전입자유도 X-선방출분광법, X-선 형광분석법과 원자흡수분광법을 이용한 세계 39개 실험실이 참여한 실험실간 비교시험에 참여하였으며 수집된 결과를 통계처리하였다. 평균값과 표준편차로 계산한 z-score는 몇개의 원소를 제외하고 모두 -1

• 분석과학
• /
• 제15권5호
• /
• pp.433-438
• /
• 2002

국제원자력기구로부터 제공받은 2종 (V-50, P-50)의 인공적으로 준비된 여과지상의 도시분진시료중의 미량원소를 중성자방사화분석법을 사용하여 비파괴 분석하였다. 중성자방사화분석의 품질관리를 위해 미국표준기술원의 인증표준물질 (Urban Particulate Matter, NIST SRM1648)이 사용되었으며 여과지상의 분진시료에서는 약 20종의 원소를 분석하였다. 측정결과는 실험실간 비교 및 숙련도 평가를 위하여 중성자방사화분석법, 하전입자유도 X-선 방출분광법, 유도결합플라즈마 질량분석법 등을 이용한 세계 40개국, 49개 실험실의 분석값들과 함께 통계처리 되었다. 통계 처리한 결과, 본 실험실의 분석값들의 Z-score가 ${\pm}2$ 이내에 들어오는 결과를 얻었으며, 숙련도 시험도 분석된 모든 원소의 정확도와 정밀도가 기준에 통과되는 신뢰성 있는 결과를 얻어 현재 수행하고 있는 대기분진시료들의 분석품질관리가 적합함을 입증하였다.

• 대한화학회지
• /
• 제7권2호
• /
• pp.165-169
• /
• 1963

시금공정의 시료중의 금의 정성 및 정량을 열중성자에 의한 방사화분석으로 조사하였다. 회수률은 81.0∼93.6%이고 결과는 재현성이 좋았다. 정양적 결과는 ${\gamma}$-Spectrometric photopeak-area counting으로 얻었으며 속중성자반응으로 인한 간섭은 무시할 수 있었다.

• 대한화학회지
• /
• 제5권1호
• /
• pp.26-28
• /
• 1961

Microgram quantities of thallirum in meteorites, rocks, minerals, alloys and biological samples have been analyzed by rapid neutron activation analysis. A l0-minute radiochemical separation procedure coupled with a gas-flow proportional detector for 4.2-minute half life measurement and a gamma or beta scintillation detector placed in close proximity to the sample permitted detection of the 4.2-min Tl206. Samples were irradiated for 10-minutes at a thermal neutron flux of approximately $0.95{\times}10^{11}$ neutron-$cm^{-2}-sec^{-1}.$ The low limits of detection was about $10^{-7}$ gm of thallium.

• Bulletin of the Korean Chemical Society
• /
• 제10권1호
• /
• pp.30-32
• /
• 1989

Traces of nine elements, gold, arsenic, cobalt, chromium, copper, europium, hafnium, sodium and antimony in commercially available silicon crystals were determined by the instrumental neutron activation analysis using the single comparator method. The values of the concentrations of these elements in both single and polycrystals were found to decrease significantly to a low limiting level by simply washing and etching surface contaminants having been introduced during various steps of sample preparation and irradiation. However, the chromium levels in polycrystals were not easily decreased, these depending upon the cutting tools employed. The Sb-doped content in each semiconductor has been compared with the associated quantities such as the concentration and the conductivity range given by the sample donor. Uncertainty in the sodium analysis due to the fission neutron reaction by silicon itself was discussed.

• Nuclear Engineering and Technology
• /
• 제4권2호
• /
• pp.83-89
• /
• 1972

중성자 선속 모니타로써 단 수명 방사성 동위원소인 $^{56}$ Mn을 이용한 새로운 비교법을 사용하여 모나자이트중에 함유된 개개 희토류원소의 함량을 중성자 방사화법으로 정량하였다. 전회토류원소를 군으로 분리하고 난 다음 중성자 조사를 하였으며 개개 희토류 원소는 양이온 교환수지통을 통하여 알파 하이드록씨 부탈산으로 구배 용출시킴으로서 분리하였다. 루데슘으로 부터 란타늄까지 14개의 희토류원소를 정량하였다.

• Advances in Energy Research
• /
• 제3권2호
• /
• pp.125-131
• /
• 2015

Prompt neutron lifetime calculations have been performed for the NIRR-1 reactor HEU and LEU cores using the 1/v insertion and the Adjoint flux weighing methods. Results of calculations obtained for the HEU and LEU cores are respectively $57.3{\pm}0.8$ and $47.5{\pm}0.7$ for the 1/v insertion and $56.9{\pm}0.3$ and $46.3{\pm}0.5$ for the Adjoint flux. There is a good agreement seen between the two methods for both cores. The prompt neutron lifetime was observed to be shorter in the LEU than for the HEU as expected. However, the Adjoint flux weighing method seemed to be the easiest method in calculating the prompt neutron lifetime for NIRR-1.

• Nuclear Engineering and Technology
• /
• 제15권2호
• /
• pp.160-168
• /
• 1983

About 25 years ago, halfway along the recorded history of the neutron as a separate entity, Korea entered the nuclear age and initiated its own neutron research and development programs. Since that time Korean scientists have taken all possible advantages of the special opportunities offered by the neutron. Scientists the world over, in the Far East, hear East, and the West, have adapted these opportunities to their special needs. These needs are manifested in all phases of modern life, including power generation by nuclear means, food preservation, production of new types of food-bearing plants, commercial uses of activation analysis, irradiations, and isotope production, nuclear medicine, industrial quality control through nuclear measurements, and direct use of neutrons in research in many areas including solid state physics, chemistry, physics, biology, and medicine. Research with neutrons has been successfully conducted using nuclear research reactors of all sizes ranging from the very small (∼10 kilowatts) to the very large(50-100 Megawatts). This speaker has teen associated with nuclear research since 1945 and directly with neutron research since 1957. From this continuous research and development activity, he will report on some of the prospects in the second 50 years of the neutron.

• Nuclear Engineering and Technology
• /
• 제37권5호
• /
• pp.503-510
• /
• 2005

An instrumental neutron activation analysis was used to measure the concentrations of about 24 elements associated with airborne particulates (PM10) that were collected in the most polluted urban region of Daejeon city, Korea from 2000 to 2002. Using the measurement data for various elements, both the extent of elemental pollution in the study area and the seasonality in their distribution characteristics were examined. Examinations of their distribution patterns indicated that most elements with crustal origin tend to exhibit seasonal peaks during spring, while most elements with anthropogenic origin tend to exhibit seasonal peaks during fall or winter. In order to explain the factors regulating their mobilization properties, the data were processed by a factor analysis. Results of the factor analysis suggested competing roles of both industrial and natural source processes, despite that the study site is located at a downwind position of the industrial complex. Based on the overall results of this study, it is concluded that the site may be strongly impacted by man-made sources but the general patterns of elemental distributions in the study area inspected over a seasonal scale are quite consistent with those typically observed from natural environment.

• 환경영향평가
• /
• 제15권6호
• /
• pp.425-433
• /
• 2006

Instrumental neutron activation analysis was used to measure the concentrations of 27 elements associated with respirable particulate matter (PM10) that were collected from the Third and Fourth Industrial Complex Area of Daejeon City. The distribution patterns of elements were clearly distinguished with their concentrations varying across more than four orders of magnitude. The mean for Al were recorded to be the highest value of 1,527 $ng/m^3$, while that for In showed the lowest value of 0.1 $ng/m^3$. If compared in terms of enrichment factors, it was found that certain elements (e.g., As, Br, Cl, Cr, I, In, Sb, Se, and Zn) are enriched in PM10 samples of the study site. The results of factor analysis indicated six factors with statistical significance, which may exert dominant controls on regulating the elemental concentration levels in the study area.