• 한국수소및신에너지학회논문집
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• 제14권2호
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• pp.97-104
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• 2003

The structural transitions of the matrix and the second phases of $Ti_{1.0}Mn_{0.9}V_{1.1}$ and $Ti_{1.0}Cr_{1.5}V_{1.7}$ alloys upon hydrogenation have been investigated at 293K. The effect of hydrogen isotope on their crystal structures has been also discussed. The crystal structures, Phase abundance and lattice parameters of the hydrides were determined by the Rietveld method using X-ray diffraction data. At the experimental temperature, the $Ti_{1.0}Mn_{0.9}V_{1.1}$ alloy and $Ti_{1.0}Cr_{1.5}V_{1.7}$ alloy revealed different structural transition processes upon hydrogenation although the crystal structures of these two alloys are both BCC at room temperature. The second phases such as Ti-rich phase with $NiTi_2$ structure and $\alpha$-Ti with HCP structure absorbed hydrogen at relatively low hydrogen pressures and the phase abundance remained almost constant. This means that it is desirable to decrease the amount of the second phases as far as possible in order to increase the effective hydrogen storage capacities of the alloys. The crystal structures of corresponding isotope hydrides, the phase abundance and the lattice parameters did not depend on the kind of hydrogen isotope, but only on the hydrogen content.

• 한국해양생명과학회지
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• 제7권2호
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• pp.61-73
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• 2022

안정동위원소 분석 기법(Stable isotope analysis, SIA)은 환경과학, 생태학, 지구생물화학, 법의학, 고고학 등 다양한 연구 분야에 활용되고 있다. 본 총설에서는 수산 및 양식 연구에 안정동위원소 비 분석 기법을 활용하기 위해 필요한 배경 지식을 소개하고자 한다. 특히, 자연값(natural abundance)을 이용하는 연구에 초점을 두었고 원소가 생물의 조직으로 통합되는 과정에서 발생하는 분별작용(동위원소 비의 변화)에 대한 원리와 안정동위원소 비가 유용한 도구로서 어떤 목적으로 생태, 환경학 분야에 이용되는지, 나아가 수산 및 양식 분야에 활용 가능한 예들을 제시하고자 한다. 본 논문을 통한 안정동위원소 분야의 이해로 향후 수산학 및 양식 연구에서 안정 동위원소 비의 다양한 활용이 기대된다.

• 분석과학
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• 제24권1호
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• pp.15-23
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• 2011

본 연구에서는 미지 대사물질 동정을 위해 GC-TOF/MS의 양이온 화학적 이온화 방법(positive chemical ionization, $CI^+$)을 이용, 정확한 질량 값(accurate mass)과 동위원소 비(isotope ratio) 측정을 위한최적 조건을 확립하였다. 분자이온 $[M+H]^+$ 세기를 증가시킬 수 있는 high mass tune 방법이 사용되었으며, 화합물들의 분리 및 감도에 따른 검출조건이 고려되어 졌다. 24종의 trimethylsilyl (TMS)기로 유도체화 된 표준 대사물질들을 분석한 결과 $[M+H]^+$의 경우 이론 값 과의 절대평균오차는 6.8 ppm이였으며, 동위원소 비(M+1/M, M+2/M)의 경우는 각각 1.5%와 1.7%였다. 얻어진 질량 값과 동위원소 비를 원소조성 알고리즘에 적용한 결과 21개의 화합물의 구조식이 2순위 내에서 일치하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제7권2호
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• pp.223-229
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• 1994

The metabolic fate of methionine in rumen bacteria was studied by intraruminal administration of $^{15}N$ and $1-^{13}C$ labeled methionine in goats. Time course changes in isotopic abundance of amino acids in the rumen bacteria were determined with a computer-controlled gas-chromatograph mass spectrometer. The results from the transition of peak isotopic abundance in amino acids indicated that in rumen bacteria the $^{15}N$ or $^{13}C$ isotope in the methionine molecule was transferred rapidly to into bacteria, methionine administered intraruminally may not be retained as it is, but would be converted quickly to other metabolites in the bacteria.

• Animal cells and systems
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• 제14권4호
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• pp.297-303
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• 2010

To document the basic ecological aspects of Chaoborus species, which has never been reported in Korea, we attempted to identify the species, to monitor seasonal and vertical dynamics, and to elucidate trophic relations of the species in Sang-Chun reservoir. Using morphological characteristics, we identified the collected samples as C. flavicans. Also, we compared the distribution of C. flavicans, Daphnia rosea and chlorophyll a to observed seasonal dynamics. The increase of C. flavicans was observed 1-2 weeks after the increase of D. rosea. Survey of diel vertica migration patterns in the summer season showed that C. flavicans were in hypolimnion at daytime, but moved to the epilimnion at night. Finally, to determine trophic relationships in Sang-Chun reservoir, additional studies on the food web were undertaken by stable isotope analysis. Chaoborus flavicans I-II instars appear to be filter feeders based on carbon isotope values. Trophic levels of C. flavicans III-IV instars were shown to be higher than other zooplankto based on nitrogen isotope values.

• Mass Spectrometry Letters
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• 제5권3호
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• pp.63-69
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• 2014

In this study, we present a new isotope-coded carbamidomethylation (iCCM)-based quantitative proteomics, as a complementary strategy for conventional isotope labeling strategies, with providing the simplicity, ease of use, and robustness. In iCCM-based quantification, two proteome samples can be separately isotope-labeled by means of covalently reaction of all cysteinyl residues in proteins with iodoacetamide (IAA) and its isotope (IAA-$^{13}C_2$, $D_2$), denoted as CM and iCCM, respectively, leading to a mass shift of all cysteinyl residues to be + 4 Da. To evaluate iCCM-based isotope labeling in proteomic quantification, 6 protein standards (i.e., bovine serum albumin, serotransferrin, lysozyme, beta-lactoglobulin, beta-galactosidase, and alpha-lactalbumin) isotopically labeled with IAA and its isotope, mixed equally, and followed by proteolytic digestion. The resulting CM-/iCCM-labeled peptide mixtures were analyzed using a nLC-ESI-FT orbitrap-MS/MS. From our experimental results, we found that the efficiency of iCCM-based quantification is more superior to that of mTRAQ, as a conventional nonisobaric labeling method, in which both of a number of identified peptides from 6 protein standards and the less quantitative variations in the relative abundance ratios of heavy-/light-labeled corresponding peptide pairs. Finally, we applied the developed iCCM-based quantitative method to lung cancer serum proteome in order to evaluate the potential in biomarker discovery study.

• Journal of Forest and Environmental Science
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• 제34권1호
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• pp.66-70
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• 2018

Preliminary investigation and analysis of the effectiveness of controlling the number of ecosystem disturbance fishes residing in Togyo reservoir using the native carnivorous fish species were performed. The data were collected from August 2011 to November 2016. The release of native carnivorous fish species was carried out from the end of May, 2012 to the end of July, 2016, considering fishing ban period of Siniperca scherzeri. The comparative abundance of Lepomis macrochirus was found to be 12.8% in the first year and increased a little bit after releasing the native carnivorous fish. However, it decreased to 3.9% in the last year showing a value of less than 5%. On the other hand, the Micropterus salmoides populations tended to increase after the release of native carnivorous fish species. This seems to be the result of the segregation of habitat by interspecific competition with S. scherzeri. The M. salmoides moved from inside of the lake to edges, and to influent tributaries. Stable isotope analysis showed that Channa argus had the highest levels of nutrition, S. scherzeri and M. salmoides were in competition, and L. macrochirus was used as a feed source for released species. Changes of the fish community in the Togyo reservoir was represented by the rank abundance curves based on the results of the fish fauna. As a result, the fish group in incoming tributaries are somewhat disturbed after the release of the native carnivorous species. Similarly, the fish group in the reservoir were disturbed as well but it's gradually stabilizing afterwards. Therefore, the control of the ecosystem disturbance species using the native carnivorous fish of Korea is effective and helps to stabilize the fish community in the lake.

• 암석학회지
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• 제13권4호
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• pp.238-243
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• 2004

1943년 11월 23일 전남 고흥군 두원면에 떨어진 두원운석의 희토류원소함량을 동위원소 희석법에 의한 열이온화 질량분석기(ID-TIMS)와 유도 플라즈마 질량분석기의 두 가지 방법론을 이용하여 분석하였다. 그 결과 La과 Ce을 제외한 다른 희토류 원소의 함량은 두 방법의 결과 약 10％내외에서 일치되는 값을 보인다. 그러나 La과 Ce의 함량은 측정방법에 따라 약 70％ 이상의 차이를 보인다. 이러한 차이의 요인으로는 분석과정에 있어서 생긴 것과 시료자체가 가지고 있는 불균질성등을 고려해 볼 수가 있다. 두원운석은 희토류원소의 분포도 해석시 기준으로 많이 인용되는 Leedey 운석(미국 오클라호마 Dewey Country, 1943년 11월 25일)과 떨어진 시기에 있어서 2일의 차이밖에 나지 않으며, 암상도 매우 유사한 편이다. 그리고 Leedey 운석으로 규격화한 희토류원소의 분포도 양상에서도 거의 편평한 양상을 보여준다. 이는 두 운석이 운석학적 혹은 우주화학적으로 매우 밀접한 연관성이 있을 것임을 시사해주는 것이다.

• Journal of Applied Biological Chemistry
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• 제44권3호
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• pp.135-139
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• 2001

To observe the changes in isotopic composition (${\delta}^{15}N$) of $NO_3{^-}$ during denitrification, an incubation experiment using soil treated with nitrification inhibitor (2-chloro-6-trichloromethyl-pyridine) under water-saturated condition was conducted for 153 h. The $NO_3-N$ concentration decreased from 73.3 to $20.6mg\;kg^{-1}$ during the incubation period, with denitrification rate constant of $0.00905h^{-1}$, and ${\delta}^{15}N$ values of $NO_3-N$ increased from +0.9 to +25.5‰ with decreasing the $NO_3-N$ concentration. The increase in the ${\delta}^{15}N$ values of $NO_3-N$ is due to kinetic isotope fractionation, which always results in $^{15}N$ enrichment of the substrate. The isotopic fractionation factor calculated in this study was 1.0196, an indication that 1.96% more $^{14}NO_3{^-}$ reacted at a given time interval than a comparable number of $^{15}NO_3{^-}$. The ${\delta}^{15}N$ values measured through the incubation study showed a good agreement with the results calculated from the Fochts isotope fractionation model. Our results suggest that when the ${\delta}^{15}N$ of $NO_3{^-}$ is used for tracing the fate of N, the kinetic isotope fractionation associated with denitrification must be taken into consideration.

• Journal of Astronomy and Space Sciences
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• 제17권2호
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• pp.147-150
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• 2000

A fluorescent equilibrium model for the 1-0 band of the A-X system of ${18}^{OH}$ has been constructed. Line positions and intensities have been calculated for possible future spectroscopic observations of these bands from space in order to derive ${18}^{O}/{16}^{O}$ ratios in comets. It is demonstrated that the strong lines of the 1-0 band can be observable for a moderately bright comet using a high resolution spectrometer with a reasonable exposure time.