• Proceedings of the Korean Nuclear Society Conference
• /
• 1998.05b
• /
• pp.551-556
• /
• 1998

The correlation of isotope composition of Zr with the turnup and some heavy isotopes in PWR uranium dioxide fuel has been investigated. The total and partial ($^{235}$ U) burnup were determined by $^{148Nd}$ and by U and Pu mass spectrometric method, respectively. After separating Zr from the fuel samples, its isotope composition was measured by mass spectrometry. In addition, the quantities of the U and Pu in the spent fuel were determined by isotope di lution mass spectrometric method using $^{233}$ U and $^{242}$ Pu as spikes. The content of some heavy isotopes, $^{235}$ U, $^{239}$ Pu and $^{241}$ Pu, and the Pu Contribution to total turnup were expressed by the correlation with Zr isotope ratios, $^{91}$ Zr/$^{96}$ Zr and $^{93}$ Zr/$^{96}$ Zr The correlations by isotope compositions measured were compared wi th those calculated from ORIGEN2 code.

• Childhood Kidney Diseases
• /
• v.1 no.1
• /
• pp.97-100
• /
• 1997

Rupture or contrast extravasation of urinary bladder after voiding cystourethrography(VCUG) was a very rare complication which occurred in neurogenic or unused bladder. Only one case of bladder extravasation was reported in a girl with normal bladder function. Case: A 18 month-old boy presented with recurrent E. Coli urinary tract infection and was evaluated with isotope VCUG, which was failed to catheter insertion. Two days later, isotope VCUG was repeated with difficult catheter insertion. Two hours after isotope VCUG, gross hematuria and anuria developed, and abdominal distension was followed. Bladder rupture was diagnosed by abdominal sonography and computerized tomography. He was treated with simple closure and suprapubic catheter drainage.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.198-203
• /
• 2003

The effects of salmon carcasses on forest and stream ecosystems were determined by nitrogen stable isotope analysis in natural streams in Hokkaido, Northern Japan, where numerous chum salmon (Oncoryhncus keta) were migrated upstream ITom ocean to spawn in autumn. The leaves and soils surrounding riparian forest and stream dwelling invertebrates were collected before and after migration. The nitrogen stable isotope ratio $({\delta}^{15}N)$ of riparian vegetation (Salix spp.) were different depending on the presence of salmon and distance from the stream. The $({\delta}^{15}N)$ of stream dwelling invertebrates were different between salmon present and absent stream. This difference was tested using the experiment channel by implanting salmon carcasses. The nitrogen stable isotope ratio of epilithic algae and leaf shredding animals were nearly 3 higher in the salmon implanted treatment suggesting that around 20％ of salmon derived nitrogen was uptake either in algae and leaf shredding invertebrates. These results suggest that the salmon carcasses effects not only on stream primary production but also on primary consumers, which decompose leaves fertilized with nitrogen from carcasses.

• Korean Journal of Microbiology
• /
• v.45 no.1
• /
• pp.1-9
• /
• 2009

Microbes within complex communities show quite different physiology from pure cultured microbes. However, historically the study of microbes has focused on single species in pure culture and most of microbes are unculturable in our labs, so understanding of complex communities lags behind understanding of pure cultured cells. Methodologies including stable isotope probing (SIP), a combination of fluorescence in situ hybridization (FISH) and microautoradiography (MAR), isotope micrarray, and metagenomics have given insights into the uncultivated majority to link phylogenetic and functional information. Here, we review some of the most recent literatures, with an emphasis on methodological improvements to the sensitivity and utilities of these methods to link phylogeny and function in complex microbial communities.

• Analytical Science and Technology
• /
• v.13 no.6
• /
• pp.789-801
• /
• 2000

This analysis was conducted for PCDDs/PCDFs in sediment by isotope dilution HRGC/HRMS method. From the result, the mean recovery of surrogate standard was in the range of 70.1-80.8%. Among the distribution of 2, 3, 7, 8-substituted isomers, the concentration of OCDD represented almost 40.6-78.5% of total concentration and that of OCDF showed 6.6-14.7% and 1, 2, 3, 4, 6, 7, 8-HpCDD showed 5.1-7.7%. The portion of PCDDs represented 62.4-86.9% of total PCDDs/PCDFs. In the TEQ concentration 1, 2, 3, 4, 7, 8-PeCDF concentration represented 22.7-35.6 % of total TEQ concentration.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.10
• /
• pp.2959-2962
• /
• 2013

As the concentration of aqueous $CD_3OH$ solutions was decreased, the OD peaks in $^2H$ NMR spectra grew relative to the $CD_3$ peaks. Isotope impurity for OH groups of $CD_3OH$ and deuterium naturally present in water contributed to the OD peaks. Using these peak area data, the site-specific isotope populations of isotope enriched chemicals were measured. In addition, the method using both $^1H$ and $^2H$ NMR spectroscopy was demonstrated with neat $CD_3OH$ to measure the site-specific isotope populations. The results indicate that although it represents only ~0.015% of hydrogen isotopes, the deuterium naturally present in solvents cannot be ignored, especially when the concentration of deuterium-enriched solutes is varied. Proton/deuteron exchange between methyl and methyl/hydroxyl groups was confirmed to be negligible, while that among hydroxyl groups was detectable.

• Korean Journal of Materials Research
• /
• v.30 no.12
• /
• pp.655-659
• /
• 2020

Hydrogen isotopes (i.e. deuterium and tritium) are supplied to the tokamak in the International Thermonuclear Experimental Reactor (ITER) fuel cycle. One important part of the ITER fuel cycle is the recycling of unused fuel back to the tokamak, as almost 99 % of fuel is unburned during fusion reaction. For this, cryogenic distillation has been used in the isotope separation system (ISS) of ITER, but this technique tends to be energy-intensive and to have low selectivity (typically below 1.5 at 24 K). Recently, efficient isotope separation by porous materials has been reported in the so-called quantum sieving process. Hence, in this study, hydrogen isotope adsorption behavior is studied using chemically stable ZIF-11. At low temperature (40 K ~ 70 K), the adsorption increases and the sorption hysteresis becomes stronger as the temperature increases to 70K. Molar ratio of deuterium to hydrogen based on the isotherms shows the highest (max. 14) ratio at 50 K, confirming the possibility of use as a potential isotope separation material.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.19 no.4
• /
• pp.447-457
• /
• 2021

Graphite Isotope Ratio Method (GIRM) can be used to estimate plutonium production in a graphite-moderated reactor. This study presents verification results for the GIRM combined with a 3-D polynomial regression function to estimate cumulative plutonium production in a graphite-moderated reactor. Using the 3-D Monte-Carlo method, verification was done by comparing the cumulative plutonium production with the GIRM. The GIRM can estimate plutonium production for specific sampling points using a function that is based on an isotope ratio of impurity elements. In this study, the ¹⁰B/¹¹B isotope ratio was chosen and calculated for sampling points. Then, 3-D polynomial regression was used to derive a function that represents a whole core cumulative plutonium production map. To verify the accuracy of the GIRM with polynomial regression, the reference value of plutonium production was calculated using a Monte-Carlo code, MCS, up to 4250 days of depletion. Moreover, the amount of plutonium produced in certain axial layers and fuel pins at 1250, 2250, and 3250 days of depletion was obtained and used for additional verification. As a result, the difference in the total cumulative plutonium production based on the MCS and GIRM results was found below 3.1% with regard to the root mean square (RMS) error.

• Korean Journal of Materials Research
• /
• v.31 no.8
• /
• pp.465-470
• /
• 2021

Deuterium is a crucial clean energy source required for nuclear fusion and is a future resource needed in various industries and scientific fields. However, it is not easy to enrich deuterium because the proportion of deuterium in the hydrogen mixture is scarce, at approximately 0.016 %. Furthermore, the physical and chemical properties of the hydrogen mixture and deuterium are very similar. Therefore, the efficient separation of deuterium from hydrogen mixtures is often a significant challenge when using modern separation technologies. Recently, to effectively separate deuterium, studies utilizing the 'Kinetic Quantum Sieving Effect (KQS)' of porous materials are increasing. Therefore, in this review, two different strategies have been discussed for improving KQS efficiency for hydrogen isotope separation performance using nanoporous materials. One is the gating effect, which precisely controls the aperture locally by adjusting the temperature and pressure. The second is the breathing phenomenon, utilizing the volume change of the structure from closed system to open system. It has been reported that efficient hydrogen isotope separation is possible using these two methods, and each of these effects is described in detail in this review. In addition, a specific-isotope responsive system (e.g., 2nd breathing effect in MIL-53) has recently been discovered and is described here as well.

• The Korean Journal of Malacology
• /
• v.12 no.2
• /
• pp.105-108
• /
• 1996

In archaeology, oxygen isotope analysis using marine shells has been used to reconstruct past environment and determine the season of shellfish-gathering activities in the past. Modern oysters(Crassostrea gigas) from Solsum ao the mouth of Chonsu Bay were anayzed to examine the potential of the species for determining seasonality by oxygin isotope analysis. As a result, it appears that the species can be used for this purpose.