• Economic and Environmental Geology
• /
• v.56 no.5
• /
• pp.557-564
• /
• 2023

Nuclear materials such as uranium are used as fuel for nuclear power generation, but there is a high possibility that they will be used for non-peaceful purposes, so international inspections and regulations are being conducted. Isotope analysis data of fine particulate obtained from nuclear facilities can provide important information on the origin and concentration method of nuclear material, so it is widely used in the field of nuclear safety and nuclear forensics. In this study we describe the analytical method that can directly identify nuclear particles and measure their isotopic ratios for fine samples using a large-geometry secondary ion mass spectrometer and introduce its preliminary results. Using the U-200 standard material, the location of fine particles was identified and the results consistent with the standard value were obtained through microbeam analysis.

• Analytical Science and Technology
• /
• v.32 no.6
• /
• pp.262-270
• /
• 2019

The stable isotopic composition of bone collagen plays an important role in reconstructing palaeodiet, nutrition, palaeoenvironment and their lifestyle. This is the first case in extracting palaeodietary information and breastfeeding pattern of Goryeo people using stable isotope analysis due to the lack of human remains in this period. We analyzed human bone collagen excavated from Gyeongju Donggung palace and Wolji pond No.3. The average values of δ¹³C and δ¹⁵N are as follows: (δ¹³C(‰) = -19.5 ± 0.9‰, δ¹⁵N(‰) = 11.1 ± 1.1 ‰, (n = 4). Stable carbon isotope values shows a mainly C₃ based diet such as rice and barley. Stable nitrogen isotope results implies the protein sources attributed to terrestrial animals. There are various age groups in this study, which are adult, child and infant. Two individuals within early childhood age ranges (< 3 years) shows more elevated δ¹⁵N values than that of adult and this result implies the continuation of breastfeeding in this group until the age of 3. The results provide new insight into the breastfeeding pattern of Goryeo people, where breastfeeding and weaning practices have important implication for fertility, population dynamics, migration pattern and disease.

• Economic and Environmental Geology
• /
• v.36 no.3
• /
• pp.149-157
• /
• 2003

Deep sea core samples were taken in the southwestern part of the Ulleung Basin in order to characterize the properties of shallow gases in the sediment. Amount of shallow gases in the sediments were calculated by head space techniques, and chemical and isotopic compositions of hydrocarbon gases were analyzed. Geochemical analyses were carried out on the gas bearing sediments to find out relationship between natural gas contents and organic characteristics of the sediments. Seismic characteristics of shallow gases in the sediments were also examined in this study. The amount of the hydrocarbon gases in the sediments range from 0.01% to 11.25%. Calculation of volume of gas per volume of wet sediment varies from 0.1 to 82.0 ml HC/L wet sediment. Methane consists 98% of the total hydrocarbon gases except for two samples. Based on the methane content and isotopic composition$(\delta^{13}c)$: -94.31$\textperthousand$~-55.5$\textperthousand$), the hydrocarbon gases from the sediments are generated from bacterial activities of methanogenic microbes. Contents of hydrocarbon gases are variable from site to site. Volume of shallow gases in the sediments shows no apparent trends vs. either characteristics of organic matter or particle sizes of the sediments. Gas concentration is high in the area of seismic anomalies such as blanking zone or chimney structures in the section. Physicochemically the pore water and the formation water systems are saturated with gases in these areas. Concentration of hydrocarbon gases in the sediments in these area shows favorable condition for generation of gas hydrate, as far as the other conditions are satisfied.

• Analytical Science and Technology
• /
• v.18 no.1
• /
• pp.27-34
• /
• 2005

$Li_2B_4O_7$ and $Na_2B_4O_7$ were synthesized with boron isotopic standard material for the measurement of boron isotopes of positive ions (PTIMS) such as $Li_2BO_2{^+}$ (mass 56, 57) and $Na_2BO_2{^+}$ (mass 88, 89) instead of boron mass 10 and 11. The negative ions (NTIMS) such as $^{10}BO_2{^-}$ and $^{11}BO_2{^-}$(mass 42와 43) were also measured with the same boron isotopic standard material. The precision and accuracy were compared between each method, and prescan of isobaric effect was studied. Good result was obtained from NTIMS method which provided the stable and enough peak intensities with good precision and accuracy. The measurement of boron isotopes were performed in ground water sample with about 8 ng-B ($5{\mu}L$ sample solution) obtained from IAEA for international inter-comparison analysis. The standard deviation was found to be 0.03%. Boron content of this ground water was measured using the NTIMS-IDMS. The result was $1.65{\pm}0.003ug-B/mL$ which was better precision compared to the ICP-AES result.

• Economic and Environmental Geology
• /
• v.46 no.6
• /
• pp.495-508
• /
• 2013

Recently, stable isotopes (${\delta}^{18}O$ and ${\delta}D$) of water are increasingly analyzed using laser-based technologies. These methods have advantages over Isotope Ratio Mass Spectrometry (IRMS) in that they can be used for in-situ measurements and require much less maintenance and preparation work. Two types of laser-based methods are currently available, which have different analytical principles; OA-ICOS (off-axis integrated cavity output spectroscopy) and WS-CRDS (wavelength-scanned cavity ring-down spectroscopy). In the WS-CRDS instrument, water is vaporized at controlled environment and transferred to an optical cavity by nitrogen carrier gas, and stable isotopic compositions of water vapor are measured using the degree of absorbance of specific wavelengths and the ratios of attenuation time of the laser intensity with the sensitivity of ppb to tens of ppt level. In this study, we introduce the principle of the WS-CRDS technology and the performance results including stability and comparisons with Isotope Ratio Mass Spectrometry (IRMS) and suggest possible applications of various topics in isotope hydrology.

• Journal of the Mineralogical Society of Korea
• /
• v.32 no.1
• /
• pp.71-77
• /
• 2019

New geochronological data of U-Pb, Re-Os and the lead isotope analysis of the Cu-Mo-Au mineral deposits are reported in the Trapiche and Constancia around Apurimac province, southeastern part of Peru. The measured ages were the first regional pulse of previously reported mineralization age between 28 and 33 Ma. The lead isotopic results indicate two sources of mineralization. The first source is thought to be derived from the upper crust and the second one is thought to be derived from a mixture of the upper crust and the lower crust.

• Korean Journal of Environmental Biology
• /
• v.27 no.3
• /
• pp.279-284
• /
• 2009

In order to understand food sources-metabolism for the pacific oyster (Crassostrea gigas), the stable isotope ratios of carbon (${\delta}^{13}C$) and nitrogen (${\delta}^{15}N$) of its gut, gill, and muscle as well as potential food sources (particulate organic matter, sedimentary organic matter, benthic microalgae, seagrass detritus) were determined in Dongdae Bay. Average ${\delta}^{13}C$ and ${\delta}^{15}N$ values reflect that oysters primarily fed on sedimentary organic matter as opposed to suspended organic matter during summer and winter seasons. However, the relatively enriched $^{15}N$ values of particulate organic matter (>$250{\mu}m$) and sedimentary organic matter in the summer may be due to the photosynthetic incorporation of $^{15}N$-enriched nitrogen (DIN) or the spawning events of bivalves. Specific oyster tissues (gut, gill, and muscle) revealed different metabolic pathways, which were determined through analysis of ${\delta}^{13}C$ and ${\delta}^{15}N$ in each organ. The present results suggest the determination of carbon and nitrogen stable isotopes to be a useful approach in ecological research related to the food sources- metabolism of Crassostrea gigas.

• Journal of The Korean Astronomical Society
• /
• v.35 no.4
• /
• pp.187-196
• /
• 2002

A spectral line survey is performed from 159.7 to 164.7 GHz toward Orion-KL, as an extension of our previous line survey from 138.3 to 150.7 GHz with the same 14 m radio telescope of Taeduk Radio Astronomy Observatory. Typical system temperatures were 260 - 1000 K to achieve a sensitivity of about 0.02 - 0.04 K in TA unit. A total of 63 line spectra are detected in this survey. Among them, 54 lines lines are found to be the first detections towards an astronomical source and only 9 spectral lines have been previously identified from other observations. Forty-eight of 54 lines are believed to be from the known transitions of the known molecules, while 6 lines are 'unidentified'. All detected lines are found to be from a total of 10 molecular species and their isotopic variants. The molecular species with most numerous detected transitions are $HCOOCH_3$ (22), followed by $CH_3OCH_3$ (7), $C_2H_5CN$ (7), and $SO_2$ (6). The LTE rotation diagram analysis using all homogeneous data with those from previous survey gives more reliable determination of physical quantities. The derived values of the rotation temperatures and column densities for $HCOOCH_3$, $CH_3OCH_3$, and $SO_2$ are are 75 $\~$ 197 K and $1.5 {\~}18 {\times} 10^{15}\;cm^{-2}$, respectively.

• The Korean Journal of Nuclear Medicine
• /
• v.26 no.1
• /
• pp.95-100
• /
• 1992

The radioisotopic measurement of glomerular filtration rate (GFR) has required analysis of serial blood or urine samples over several hours, and does not allow measurement of separate renal function unless separate catherterization of individual ureters is done. Gates described isotopic method for the measurement of global and unilateral GFR based on the determination by scintillation camera of the fraction of the injected dose of $^{99m}Tc-diethylenetriaminepentaacetic$ acid (DTPA) present in the kidneys 2-3 minutes after its administration. We calculated GFR according to Gates' method in 58 adult patients with various levels of global renal function using $^{99m}Tc$ DTPA and validated this technique by correlation with 24 hour creatinine clearance. A good correlation was observed between 24 hour creatinine clearance and GFR calculated by Gates' formula, with an r value of 0.91 (p<0.01). We concluded that determination of GFR according to the Gates' formula allows good and reproducible prediction of GFR with great rapidity and simplicity rendering this technique suitable for clinical practice.

• Nuclear Engineering and Technology
• /
• v.21 no.4
• /
• pp.245-258
• /
• 1989

A 69-group cross section library consisting of more than 130 materials was generated for thermal reactor applications using the NJOY nuclear data processing system and the recent version of evaluated nuclear data files available from IAEA Nuclear Data Section. The multigroup library was validated through the analysis of various criticality experiments and depletion results of PWR. When used with the WIMS-KAERI code, the average $K_{eff}$ obtained for 47 uranium-oxide and 41 uranium metal fueled critical configurations is 0.9997 with a standard deviation of 0.69 percent. The calculated burnup dependent isotopic inventories of uranium and plutonium generally show good agreement with measured values obtained from depleted PWR pins.s.