• 암석학회지
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• 제10권3호
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• pp.190-201
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• 2001

동위원소희석법은 스파이크(농축 동위원소)를 사용하여, 질량분석기에서 얻어지는 각 원소들의 동위원소 스펙트럼을 비교함으로써 정량화하는 방법으로서, 현재까지 개발된 정량분석 방법 중 가장 정확한 방법이다. 특히 열이온 질량분석기(Thermal Ion Mass Spectrometer)를 이용한 동위원소희석법은 현재까지 알려진 분석방법 중 가장 신뢰도가 높은 결과(1% 이내의 정도까지 가능함)를 얻을 수가 있다. 동위원소회석법에 의해 정량분석을 하고자 할 때, 가장 중요한 요인중의 하나로서 스파이크(농축 동위원소)의 선택이다. 회토류원소의 복합 스파이크용액을 만들 때의 개개의 회토류원소의 스파이크는 $^{138}$ $La^{142}$ , $Ce^{145}$ /Nd, $^{149}$ /, $Sm^{151}$ , $Sm^{151}$Eu, $^{157}$ Gd, $^{163}$ Dy, $^{167}$ Er, $^{171}$ , $Yb^{176}$ Lu를 많이 쓴다. 이 동위원소희석법에 의한 정량분석이 가장 유용하게 쓰여지고 있는 지구화학적 연구분야는 암석이나 광물의 연대를 측정하고자 할 때의 관심원소의 정량 및 자연계시료의 회토류 원소의 미세구조를 들 수가 있다. 특히 희토류원소의 테트라드 효과를 연구하고자 할 때, 이 동위원소희석법은 아주 효과적인 방법이다.

• Mass Spectrometry Letters
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• 제8권3호
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• pp.49-52
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• 2017

Ibuprofen is one of the most popular analgesic and antipyretic drugs. An isotope dilution mass spectrometry method based on LC/MS was developed as a candidate reference method for the accurate determination of ibuprofen in pharmaceutical tablets. Isotope labelled ibuprofen, $ibuprofen-d_3$, was added as an internal standard into sample extracts. Ibuprofen and $ibuprofen-d_3$, was analysed by LC/MS in a selected ion monitoring (SIM) mode to detect ions at m/z 205 and 208, respectively. The repeatability and reproducibility of the developed ID-LC/MS method were tested for the validation and assessment of metrological quality of the method.

• 분석과학
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• 제18권6호
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• pp.520-528
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• 2005

Two biological Certified Reference Materials (CRMs), KRISS 108-04-001 (oyster tissue) and 108-05-001 (water dropwort stem), were prepared by Korea Research Institute of Standards and Science (KRISS)during FY '01. The certified values of these materials had been determined by Isotope Dilution Mass Spectrometry (IDMS) for six elements (Cd, Cr, Cu, Fe, Pb and Zn). Additional analytical works are now progressing to certify the concentrations of a number of the environmental and nutrimental elements in these CRMs. The certified values in a CRM are usually determined by using a single primary method with confirmation by other method(s) or using two independent critically-evaluated methods. Instrumental Neutron Activation Analysis (INAA) plays an important role in the determination of certified values as it can eliminate the possibility of common error sources resulting from sample dissolution. In this study INAA procedure was used in determination of 23 elements in these two biological CRMs to acquire the concentration information and the results were compared with KRISS certified values.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.761-764
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• 2003

Islanding phenomenon of a grid-connected photovoltaic (PV) power conditioning system (PCS) is said to occur if the PCS continues to power a section of the utility system after that section has been disconnected from the utility source. Since islanding creates hazards for personnel and equipment, PCSs are required to detect and prevent Et. In this paper, several islanding detection methods (IDMs) and reactive power variation method are described. Islanding test results for 9kW PCS are presented for verification.

• Journal of Power Electronics
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• 제19권2호
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• pp.509-518
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• 2019

A novel islanding detection method is proposed in this paper. It is based on a frequency drooping PLL, which was presented in a previous work. The cause of errors in the non-detection zone (NDZ) of conventional frequency disturbance islanding detection methods (IDM) is analyzed. A frequency drooping phase-locked-loop (FD-PLL) is introduced into a single-phase grid-connected inverter (SPGCI), which can guarantee that grid current is in phase with the grid voltage. A novel FD-PLL IDM is proposed by improving this PLL. In order to verify the performance of the proposed FD-PLL IDM, a full performance comparison between the proposed IDM and typical existing active frequency drift IDMs is carried out, which includes both dynamic performance and steady performance. With the same NDZ, the total harmonic distortion of the grid-current in the dynamic process and steady state is analyzed. The proposed FD-PLL IDM, regardless of the dynamic or steady process, has the best power quality. Experimental and simulation results verify that the proposed FD-PLL IDM has excellent performance.

• Mass Spectrometry Letters
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• 제3권2호
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• pp.58-61
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• 2012

A method based on flow injection-isotope dilution-cold vapor-inductively coupled plasma mass spectrometry (FI-IDCV-ICP/MS) has been applied to determine trace level of mercury in fly ash. $^{200}Hg$ isotopic spike was added to 0.25 g of BCR176R fly ash and then decomposed by microwave digestion procedure with acid mixture A (8 mL $HNO_3$ + 2 mL HCl + 2 mL HF) and acid mixture B (8 mL $HNO_3$ + 2 mL $HClO_4$ + 2 mL HF) for applying IDMS. Mercury cold vapor was generated by using reductant solution of 0.2% (w/w) $NaBH_4$ and 0.05% (w/w) NaOH. The measurements of n($^{200}Hg$)/n($^{202}Hg$) isotope ratio was made using a quadrupole ICP/MS system. The accuracy in this method was verified by the analysis of certified reference material (CRM) of fly ash (BCR 176R). The indicative value of Hg in BCR 176R fly ash was $1.60{\pm}0.23$ mg/kg (k = 2). The determined values of Hg in BCR 176R fly ash by the method of FI-CV-ID-ICP/MS described in this paper were $1.60{\pm}0.24$ mg/kg (k = 3.18) and the analysis results were in well agreement with the indicative value within the range of uncertainty.

• Nuclear Engineering and Technology
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• 제33권4호
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• pp.375-385
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• 2001

The total burnup in the spent U$_3$Si/Al fuel samples from Hanaro reactor was determined by destructive methods using $^{148}$ Nd, the sum of $^{143}$ Nd and $^{144}$ Nd, the sum of $^{145}$ Nd and $^{146}$ Nd, and the sum of total Nd isotopes($^{143}$ Nd, $^{144}$ Nd, $^{145}$ Nd, $^{146}$ Nd, $^{148}$ Nd and $^{150}$ Nd) monitors. The fractional($^{235}$ U) turnup in the spent fuel samples was also determined by U and Pu mass spectrometric method. The samples were dissolved in a mixture of 4 M HCI and 10 M HNO$_3$ without any catalyst. The separation of U, Pu and Nd from the spiked and unspiked sample solutions was achieved by two sequential anion exchange separation methods. The isotope compositions of these elements, after their separation from the fuel samples were measured by mass spectrometry. The contents of the elements in the spent fuel samples were determined by isotope dilution mass spectrometric method(IDMS) using $^{233}$ U, $^{242}$ Pu and $^{150}$ Nd as spikes. The effective fission yield was calculated from the weighted fission yields averaged over the irradiation period. The difference between total turnup values determined by various Nd monitors were in the range of 1.8%.

• 분석과학
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• 제14권4호
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• pp.291-299
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• 2001

사용후핵연료내 핵분열생성물중 Sm 동위원소 정량을 위한 분리 및 정제에 관한 연구를 수행하였다. 일차적으로 핵분열생성물 대신 여러 비방사성 금속이온(Cs, Ba, Gd, Eu, Sm 및 Nd)들로 구성된 모의용액을 시료로 사용하였다. Sm은 AG $1{\times}8$ 음이온교환수지관에서 1 M $HNO_3$/90% MeOH 용액으로 세척 후 0.5 M $HNO_3$/80% MeOH 용액으로 용리하였다. 용출액에 함유되어 있는 미량의 Ba을 제거하기 위하여 0.2 M alpha-hydroxyisobutyric acid 용액(pH 4.5-4.6)으로 전처리한 AG $50W{\times}8$ 양이온교환수지관에서 정제하였으며, 순수한 Sm을 90% 이상 분리, 회수할 수 있었다. 실제 PWR 사용후핵연료에 함유되어 있는 Sm의 분리 및 정제에 적용하여 용출액을 질량분석한 결과 Gd, Eu, Pm, Nd 및 BaO에 의한 동중원소 영향이 나타나지 않았다. $^{154}Sm$ 스파이크를 이용한 동위원소희석 질량분석법으로 사용후핵연료 중의 Sm 및 각각의 성분 동위원소($^{147}Sm$, $^{148}Sm$, $^{149}Sm$, $^{150}Sm$, $^{151}Sm$, $^{152}Sm$ and $^{154}Sm$)들을 정량하였다.

• 분석과학
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• 제18권1호
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• pp.27-34
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• 2005

보론 동위원소 표준물을 이용하여 $Li_2B_4O_7$와 $Na_2B_4O_7$를 합성하고 이로부터 $Li_2BO_2{^+}$ (질량 56, 57)와 $Na_2BO_2{^+}$ (질량 88, 89)를 열 이온화 질량분석기를 이용하여 양이온 질량분석법(PTIMS)으로 측정하였으며 또한 같은 시료를 음이온 질량분석법 (NTIMS)으로 $^{10}BO_2{^-}$와 $^{11}BO_2{^-}$ (질량 42와 43)를 보론 (질량 10, 11)대신 측정하였다. 이들 방법 간의 정밀도와 정확도를 비교하고, 각각의 방법에서 동중원소 영향이 있는지를 알아보았다. 세 가지 방법 중에 NTIMS 방법이 제일 좋은 결과를 보여주었으며 작은 시료 양으로도 안정된 피크를 얻을 수 있었다. NTIMS 방법으로 지하수 약 $5{\mu}L$(약 8 ng-B)를 직접시료로 사용하여 보론 동위원소 비를 측정하여 상대 표준편차 0.03%의 결과를 얻었다. 또한 NTIMS-IDMS로 보론을 정량한 결과 $1.65{\pm}0.003{\mu}g-B/mL$을 얻었으며 ICP-AES 결과에 비해 좋은 정밀도를 보였다.

• 분석과학
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• 제11권4호
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• pp.271-280
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• 1998

국내에서 재배 생산된 현미로 부터 표준물질을 가공하여 원소별 검정분석을 실시하였다. 주요 오염원소의 농도가 서로 다른 2종의 쌀분말 표준물질을 제조하였는데 1종은 정상치시료로서 분말 시료를 그대로 처리하였으며, 1종은 제조과정중에 As, Cu, Pb, Hg, Cr, Cd등 6개의 중금속원소를 건조중량기준 $1.0{\mu}g/g$씩 첨가한 고농도 오염시료로서 제조하였다. 제조된 시료는 중성자방사화분석법 (NAA)과 불꽃원자흡수분광법(FAAS)으로 Cd, Cu, Fe, Mn, Zn등 5개 원소에 대한 균질도 분석을 실시하여 기준불질로서의 균질성을 확인하였다. 쌀시료의 분해 및 전처리에는 고온가압법과 마이크로파분 해법을 사용하였으며, NAA, FAAS, 흑연로원자흡수분광법(GFAAS), 유도플라즈마방출분광법(ICP-AES), 동위원소희석질량분석법(IDMS), 증기발생법 등을 이용하여 쌀분말표준물질 소재의 원소별 정량 분석을 실시하였다. 이들 각 방법의 원소별 분석결과를 이용하여 P, K, Mg, As, Ca, Cd, Cr, Cu, Fe, Mn, Mo, Na, Zn, Pb, Se, Hg등 16개 원소에 대한 검정값 및 참고값을 확정하였다.