• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.69-76
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• 2006

TRISO(tri-isotropic)-coated fuel particle technology is utilized owing to its higher stability at a high temperature and Its efficient retention capability for fission products In the HTGR(high temperature gas-reeled reactor). The typical spherical TRISO fuel panicle with a diameter of about 1mm is composed of a nuclear fuel kernel and outer coating layers. The outer coating layers consist of a buffer PyC(pyrolytic carbon) layer, Inner PyC(1-PyC) layer, SiC layer, and outer PyC(O-PyC) layer Most of the Inspection Items for the TRTSO-coated fuel particle depend on destructive methods. The coating thickness of the TRISO fuel particle can be nondestructively measured by the X-ray radiography without generating radioactive wastel. In this study, the coaling thickness for the simulated TRISO-coated fuel particle with $ZrO_2$ kernel Instead of $%UO_2$ kernel was measured by using micro-focus X-ray radiography with micro-focus X-ray generator and flat panel detector The radiographic image was also enhanced by image processing technique to acquire clear boundary lines between coating layers. The coaling thickness wat effectively measured by applying the micro-focus X-ray radiography The inspection process for the TRISO-coated fuel particles will be improved by the developed micro-focus X-ray radiography and digital image processing technology.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.387-392
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• 1997

Purpose : To quantify the movement of lung Parenchyma for ICRU 50 Planning Target Volume (PTV) delineation of the lung region. Materials and Method : Fluoroscopic observations and measurements are Performed on 10 patients with chest region cancer who have normal putmonary functions We have divided the lung region into 12 parts for the right lung, 10 parts for the left lung and four to five Points of lung parenchyma were selected for anatomical analysis Points, Fluoroscopic images are sent to a computer and then movements are measured. Results : Both lowe lobes showed the longest longitudinal movements because of breathing (average 14.1mm, maximum 22.1mm), while anteroposterior displacement showed the smallest value. Lateral movements of the lung parenchyma averaged 6.6mm, and the maximum value was 9.1mm, (both hilar regions showed maximum values because of cardiac motion) Conclusion : We could quantify the lung movements by measuring parenchyma displacements. The movements of both upper lobes were less than those of the middle and upper lobes in longitudinal and transverse movements. Optimal margins can be selected for PTV delineation using these results.

• The Journal of the Petrological Society of Korea
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• v.14 no.1
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• pp.1-11
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• 2005

Sphene U-Pb ages were determined for the granodiorites from Gimcheon, Seongju and Anui areas of the middle Yeongnam massif. The determined ages were in the narrow range of 195.7±2.4∼200.8±1.9(2σ) Ma that are approximately coincident with the boundary between Triassic and Jurassic. Even though the studed plutons are aerially separated, they reveal quite similar major element compositions and almost identical ages, suggesting that they were generated from the similar source materials under the identical tectonic environment and thus they can be considered to form a single suite. Considering the age and spatial distribution of the Triassic to Lower Jurassic plutons of the Yeongnam Massif and Okcheon Belt, it seems that there were episodic changes in tectonic environment in both areas with relatively short intervals. In general, the compressive environment of active continental margin was prevailed. However, the tensional environment of within-plate was also appeared several times intermittently. In conclusion, Yeongnam Massif and Okcheon Belt experienced distinct tectonic environments during Triassic to Lower Jurassic, providing important clue to reveal the crustal evolution of the Korean Peninsula.

• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.391-403
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• 2006

The Hanon volcano located in the southern pan of Cheju Island, Korea has a wetland in its crater being used as a farmland. Previous researchers presumed this wetland was a maar lake in the past. Based on the seismic refraction method, the wetland sediment layer was estimated between 5 to 14 m deep, which is mostly in accordance with previous researches. However, this shows only the depths at some sites, not representing the whole spatial distribution. This study is an attempt to reconstruct the volcanic lake in Hanon crater by applying the spatial statistical techniques based on the depth information from the seismic survey and known data. The procedure of reconstruction is as follows: First, the depth information from the seismic survey and known data were collected and it was interpolated by IDW and Ordinary Kriging method. Next, with the interpolation map and the present DEM the paleo DEM was constructed. Finally, using the paleo lake level on core data, the boundary of volcanic lake was extracted from the paleo DEM. The reconstructed lake resembles a half-moon in the north of the central scoria cone. It is estimated that the lake was 5 m deep on average and 13 m deep at the deepest point. Although there are slight differences according to the interpolation techniques, it is calculated that the area of the lake was between 184,000 and $190000m^2,$ and its volume approximately $869,760m^3$. Because of the continuous deposition processes after the crater formation, the reconstructed volcanic lake would not indicate an actual lake at a specific time. Nevertheless, it offers a significant clue regarding the inner morphology and evolution of the crater.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.1
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• pp.1-18
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• 2023

The East Sea, one of the regions where the most rapid warming is occurring, is known to have important implications for the response of the ocean to future climate changes because it not only reacts sensitively to climate change but also has a much shorter turnover time (hundreds of years) than the ocean (thousands of years). However, the processes underlying changes in seawater characteristics at the sea's deep and abyssal layers, and meridional overturning circulation have recently been examined only after international cooperative observation programs for the entire sea allowed in-situ data in a necessary resolution and accuracy along with recent improvement in numerical modeling. In this review, previous studies on the physical characteristics of seawater at deeper parts of the East Sea, and meridional overturning circulation are summarized to identify any remaining issues. The seawater below a depth of several hundreds of meters in the East Sea has been identified as the Japan Sea Proper Water (East Sea Proper Water) due to its homogeneous physical properties of a water temperature below 1℃ and practical salinity values ranging from 34.0 to 34.1. However, vertically high-resolution salinity and dissolved oxygen observations since the 1990s enabled us to separate the water into at least three different water masses (central water, CW; deep water, DW; bottom water, BW). Recent studies have shown that the physical characteristics and boundaries between the three water masses are not constant over time, but have significantly varied over the last few decades in association with time-varying water formation processes, such as convection processes (deep slope convection and open-ocean deep convection) that are linked to the re-circulation of the Tsushima Warm Current, ocean-atmosphere heat and freshwater exchanges, and sea-ice formation in the northern part of the East Sea. The CW, DW, and BW were found to be transported horizontally from the Japan Basin to the Ulleung Basin, from the Ulleung Basin to the Yamato Basin, and from the Yamato Basin to the Japan Basin, respectively, rotating counterclockwise with a shallow depth on the right of its path (consistent with the bottom topographic control of fluid in a rotating Earth). This horizontal deep circulation is a part of the sea's meridional overturning circulation that has undergone changes in the path and intensity. Yet, the linkages between upper and deeper circulation and between the horizontal and meridional overturning circulation are not well understood. Through this review, the remaining issues to be addressed in the future were identified. These issues included a connection between the changing properties of CW, DW, and BW, and their horizontal and overturning circulations; the linkage of deep and abyssal circulations to the upper circulation, including upper water transport from and into the Western Pacific Ocean; and processes underlying the temporal variability in the path and intensity of CW, DW, and BW.

• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1211-1224
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• 2023

Clouds cause many difficult problems in observing land surface phenomena using optical satellites, such as national land observation, disaster response, and change detection. In addition, the presence of clouds affects not only the image processing stage but also the final data quality, so it is necessary to identify and remove them. Therefore, in this study, we developed a new cloud detection technique that automatically performs a series of processes to search and extract the pixels closest to the spectral pattern of clouds in satellite images, select the optimal threshold, and produce a cloud mask based on the threshold. The cloud detection technique largely consists of three steps. In the first step, the process of converting the Digital Number (DN) unit image into top-of-atmosphere reflectance units was performed. In the second step, preprocessing such as Hue-Value-Saturation (HSV) transformation, triangle thresholding, and maximum likelihood classification was applied using the top of the atmosphere reflectance image, and the threshold for generating the initial cloud mask was determined for each image. In the third post-processing step, the noise included in the initial cloud mask created was removed and the cloud boundaries and interior were improved. As experimental data for cloud detection, CAS500-1 L2G images acquired in the Korean Peninsula from April to November, which show the diversity of spatial and seasonal distribution of clouds, were used. To verify the performance of the proposed method, the results generated by a simple thresholding method were compared. As a result of the experiment, compared to the existing method, the proposed method was able to detect clouds more accurately by considering the radiometric characteristics of each image through the preprocessing process. In addition, the results showed that the influence of bright objects (panel roofs, concrete roads, sand, etc.) other than cloud objects was minimized. The proposed method showed more than 30% improved results(F1-score) compared to the existing method but showed limitations in certain images containing snow.

• Economic and Environmental Geology
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• v.49 no.5
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• pp.349-360
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• 2016

This study determined mineralogical characteristics and discussed the meaning of mineralogical changes of the lower Choseon Supergrouop in the Weondong area based on the field geological investigation and the drilling core description using X-ray diffraction (XRD) mineral quantification and Scanning Electron Microscopy (SEM) observation. 100 samples with depth were collected from the core (250 m long) at a site in the study area. Especially, to investigate the changes from the upper Daegi Formation to the lower Hwajeol Formation, the samples were collected closely with the interval of about 0.3 m at this section. All samples were made into power using mortar for XRD. Mineral quantitative analysis was executed using Relative Intensity Ratio (RIR) method with corundum as an internal standard phase. Calcite, $2M_1$ illite and quartz are main constituents in most of samples. Dolomite and siderite are significantly observed in the Sesong Formation. As the results of quantitative analysis for the major minerals, the upper Daegi Formation is dominated by calcite with over 80%. The Sesong Formation includes high percentage of dolomite and siderite with the intercalation of thin layers containing high calcite and $2M_1$ illite contents. Hwajeol Formation is characterized by the alternation between thin layers of $2M_1$ illite and quartz-dominated layer (IQDL) and calcite-dominated layer (CDL). IQDL is more frequent in the lower part, whereas CDL is more common in the upper part. The boundary between Daegi Formation and the Sesong Formation is distinct, whereas the boundary between the Sesong Formation and the Hwajeol Formation tends to be changed gradually in mineralogy. The result of SEM observation shows that quartz and $2M_1$ illite are detrital, and a significant amount of calcite also shows detrital form with some recrystallized one, indicating that the repeated influx of terrestrial materials had changed the mineralogy of the shallow sea depositional environment in the early Paleozoic era.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.128-136
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• 2006

This study was conducted for developing the stability parameter in uncontrolled landfill by using a biomolecular investigation on the microbial community growing through leachate plume. Landfill J(which is in Cheonan) and landfill T(which is in Wonju) were chosen for this study among a total of 244 closed uncontrolled landfills. It addressed the genetic diversity of the microbial community in the leachate by 165 rDNA gene cloning using PCR and compared quantitative analysis of denitrifiers and methanotrophs with the conventional water quality parameters. From the BLAST search, genes of 47.6% in landfill J, and 32.5% in landfill T, respectively, showed more than 97% of the similarity where Proteobacteria phylum was most significantly observed. It showed that the numbers of denitrification genes, i.e. nirS gene and cnorB gene in the J site are 7 and 4 times higher than those in T site, which is well reflecting from a difference of site closure showing 7 and 13 years after being closed, respectively. In addition, the quantitative analysis on methane formation gene showed that J1 spot immediately bordering with the sources has the greatest number of methane formation bacteria, and it was decreased rapidly according to distribute toward the outer boundary of landfill. The comparative investigation between the number of genes, i.e. nirS gene, cnorB gene and MCR gene, md the conventional monitoring parameters, i.e. TOC, $NH_3-N,\;NO_3-N,\;NO_2-N,\;Cl^-$, alkalinity, addressed that more than 99% of the correlation was observed except for the $NO_3-N$. It was concluded that biomolecular investigation was well consistent with the conventional monitoring parameters to interpret their influences and stability made by leachate plume formed in downgradient around the uncontrolled sites.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.36-44
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• 2010

The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.

• Journal of Popular Narrative
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• v.25 no.1
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• pp.349-392
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• 2019

In the 1960s of Korea, the normalization of diplomatic relations between Korea and Japan led to a sense of a vigorous anxiety and fear that "Japan will once again come to the Korean peninsula". As a reaction to this, the discourse on the criticism of 'Japanese Style' strongly emerged. If the prior discourse of criticism was to express the national antipathy toward the colonial remnants that had not yet been disposed of, the critical discourse of the 1960s was the wariness of the newly created 'Japanese Style' in popular culture, and to grasp it as a symptomatic phenomenon that 'evil-minded Japan' was revealed. Thus, this new logic of criticism of the 'Japanese Style' had a qualitative difference from the existing ones. It was accompanied by a willingness to inspect and censor the 'masses' that grew up as consumers of transnational 'mass culture' that flowed and chained in the geopolitical order under the Cold War system. Therefore, the topology of 'popular things=Japanese things=consuming things' reveals the paradox of moral demands that existed within Korean society in the 1960s. This was to solidify the divisive circulation structure that caused them to avoid direct contact with the other called 'Japan', but at the same time, get as close to it as ever. It is a repetitive obsession that pushes the other to another side through the moral segregation that strictly draws a line of demarcation between oneself and the other, but on the other hand is attracted to the object and pulls it back to its side. This paper intends to listen to the different voices that have arisen in the repetitive obsession to understand the significance of the dissonance that has been repeated in the contemporary era. This will be an examination of the paradoxical object of Japan that has been repeatedly asked to build the internal control principle of Korean society, or to hide the oppressive and violent side of the power, and that can neither be accepted nor destroyed completely as part of oneself.