• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.117-121
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• 2010

Purpose: In nuclear medicine study, there are two methods, preset count method and preset time method, to acquire static images. We usually use preset count method for static image in $^{99m}Tc$-DMSA renal scan, but occasionally use preset time method. In case of using preset count method, we always acquire same counts but it causes a difference of scan time. In case of using preset time method, it takes same scan time to acquire images but it causes different counts. Therefore, the purpose of this study is to investigate any differences of function and formal information in both kidney by acquisition counts Materials and Methods: From January 11, 2010 to March 31, 2010, we analyzed the 30 patients (M: 11, W: 19). who were examined by $^{99m}Tc$-DMSA scan and have one side of functioning kidney relatively between 40~60%. And the patients who have cold and hot region in image were analyzed but we did not accept images of patients when it was hard to divide kidney into cortex. There was no division between subjects and age of subjects is $14.83{\pm}22.07$ old. We used the BrightView gamma camera from PHILIPS. To analyze function and formal of kidney, we used JET stream release 3.0 version from PHILIPS. Using SPSS 12.0 program, we compared descriptive statistics and paired T-test. Images were acquired sequentially in the same parameters, but there are three methods which different from acquisition time and scan time, 100 kcounts, 300 kcounts and 7 minutes method (exceed 300 kcounts). To assess function and formal information of kidney, we measured renal relative function, geometric mean and size of kidney and analyzed each difference. Results: In case of renal relative function in both kidney, 100 kcounts method was $50.52{\pm}3.64%$. 300 kcounts method was $50.38{\pm}3.66%$ and 7 minutes method was $49.91{\pm}3.40%$ and there were no statistical significant differences between each method. In case of geometric mean, 100 kcounts method was $50.08{\pm}3.25%$. 300 kcounts method was $49.89{\pm}3.40%$ and 7 minutes method was $49.91{\pm}3.24%$. And also, there were no statistical significant differences. When comparing size of kidney, 100 kcounts method was $8.23{\pm}1.96$ cm. 300 kcounts method was $8.12{\pm}1.90$ cm and 7 minutes method was $8.35{\pm}1.97$ cm. In case of right kidney, 100 kcounts method was $7.91{\pm}1.88$ cm. 300 kcounts method was $8.12{\pm}1.90$ cm and 7 minutes method was $8.25{\pm}1.96$ cm. From those values, we recognized that there were significant differences each method (p<0.05). Conclusion: From results of this study, there were no statistical differences in renal relative function and geometric mean by acquisition counts. However, in shape of kidney, the more acquisition counts are increasing, the more size of kidney is getting big. And there were statistical significant differences. Therefore, to perform reliable quantitative result, preset count method is more desirable than preset time method. Especially, in case of a follow-up test, if we use preset time method, it will cause differences of formal results in kidney due to acquisition counts each time we examine patients.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.428-436
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• 2010

This study was to evaluate water quality characteristics and ecological health using a mulimetric fish model in Taehwa-River watershed during May~September 2009. The ecological health assessments were based on the Index of Biological Integrity (IBI) using fish community and the multimetric model of Qualitative Habitat Evaluation Index (QHEI). For the study, the models of IBI and QHEI were modified as 8 and 11 metric attributes, respectively. We also analyzed spatial patterns of chemical water quality over the period of 2000~2009, using the water chemistry dataset, obtained from the Ministry of Environment, Korea. Values of BOD and COD averaged $1.7\;mg\;L^{-1}$ (scope: $0.1{\sim}31.8\;mg\;L^{-1}$) and $3.6\;mg\;L^{-1}$ (scope: $0.4{\sim}33\;mg\;L^{-1}$), respectively during the study. Total nitrogen (TN) and total phosphorus (TP) averaged $2.8\;mg\;L^{-1}$ and $96.8\;{\mu}g\;L^{-1}$, respectively, indicating an eutrophic-hypertrophic state. Also, TN and TP showed longitudinal increases toward the downriver reach. In the watershed, QHEI values varied from 67.5 (fair condition) to 164.5 (good condition) by the criteria of US EPA (1993). There was a abruptly decreasing tendency from T9 site in the QHEI values. According to 1st and 2nd surveys of Taewha River, multimetric model values of IBI was averaged 26.1 (n=14) with "good" condition (B) and the spatial variation was evident. Our results suggest that the mainstream sites was getting worse health condition along the river gradient due to inputs of the point and non-point sources from the urban (Ulsan city). Overall, dataset of IBI, QHEI, and water chemistry indicated that the ecological river health showed a downriver decline and the pattern was closely associated with habitat degradations and chemical pollutions as the waters pass through the urban region.

• The Korean Journal of Malacology
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• v.17 no.1
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• pp.45-55
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• 2001

Gametogenes, reproductive cycle, first sexual maturity(biological minimum size), sex ratio and larval development of the marsh clam Corbicula japonica were investigated monthly by histological observations. Samples were collected in brackish water of Gokgang stream, Kyungsangbuk-Do, Korea, from August 1997 to July 1998. Sexuality of Corbicula japonica is dioecious and the species are an oviparous clam. The gonads are irregularly arranged from the sub-region of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of ovarian sac which are branched arborescent. Oogonia actively proliferate along the germinal epithelium of ovarian sac, in which young oocytes are growing. The testis is composed of a number of testicular tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between developing oocytes and spermatocytes in the early developmental stages. With the further development of the ovary and testis these tissue and cells gradually disappear. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells are considered to be related to the growing of the oocytes and spermatocytes. The spawning period is from July to September, and the main spawning occur between July and August when seawater temperatures reach above 22$^{\circ}C$. The reproductive cycle of this species can be divided into five successive stages; early active (February to April), late active (May to July), ripe (June to September), partially spawned (July to September), degenerative (September to October) and resting stage (October to February). Percentages of first sexual maturity of female and male clams ranging in length from 10 mm to 12 mm are over 50% and 100% for clams over 16.0 mm in shell length. Fertilized eggs or Corbicula japonica were 80-90 ${\mu}{\textrm}{m}$ in diameter. In the early embryonic development of C. japonica, the appearance of polar body, trochophore and D-shaped veliger were observed around 40 min., 27 hours and 4 days after spawning, respectively, at a water temperature of 26.5-28.$0^{\circ}C$. The size of larvae of early umbo stage was about 185-210 ${\mu}{\textrm}{m}$ in shell length, 160-180 ${\mu}{\textrm}{m}$ in shell height around 7 days after fertilization. The correlation of relative growth between the culture day (D) and shell length (SL) was expressed by the following simple formula from D-shaped veliger to metamorphosing stage; SL = 13.300D + 209.36($r^2$= 0.9078).

• Journal of the Korean earth science society
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• v.38 no.3
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• pp.194-208
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• 2017

This study analyzed the correlation between tropical cyclone (TC) frequency and the western North Pacific monsoon index (WNPMI), which have both been influential in East China Sea during the summer season over the past 37 years (1977-2013). A high positive correlation was found between these two variables, but it did not change even if El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) years were excluded. To determine the cause of this positive correlation, the highest (positive WNPMI phase) and lowest WNPMIs (negative WNPMI phase) during an eleven-year period were selected to analyze the mean difference between them, excluding ENSO years. In the positive WNPMI phase, TCs were mainly generated in the eastern seas of the tropical and subtropical western North Pacific, passing through the East China Sea and moving northward toward Korea and Japan. In the negative phase, TCs were mainly generated in the western seas of the tropical and subtropical western North Pacific, passing through the South China Sea and moving westward toward China's southern regions. Therefore, TC intensity in the positive phase was stronger due to the acquisition of sufficient energy from the sea while moving a long distance up to East Asia's mid-latitude. Additionally, TCs occurred more in the positive phase. Regarding the difference in 850 hPa and 500 hPa stream flows between the two phases, anomalous cyclones were strengthened in the tropical and subtropical western North Pacific, whereas anomalous anticyclones were strengthened in East Asia's mid-latitude regions. Due to these two anomalous pressure systems, anomalous southeasterlies developed in East China Sea, which played a role in the anomalous steering flows that moved TCs into this region. Furthermore, due to the anomalous cyclones that developed in the tropical and subtropical western North Pacific, more TCs could be generated in the positive phase.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.676-683
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• 2016

This study was conducted using the Wild -Tracker (WT-300, GPS-Mobile Phone Based Telemetry KoEco) to understand the habitats of the spot-billed duck wintering in urban and rural areas and provide the results as the basic data for the protection and management of the habitats of the waterbirds in Korea. Study areas consisted of the Anseong stream in Gyeonggi-do and the Sansu reservoir in Haenam. Five spot-billed ducks were captured by region, and we attached Wild-Tracker to each of the spot-billed ducks. We analyzed the tracking location data using ArcGIS 9.x and calculated Kernel Density Estimation (KDE) and Minimum Convex Polygon (MCP). The average home-range measured by MCP was $250.8km^2$(SD=195.3, n=5) in Anseong and was $89.1km^2$ (SD=69.6, n=5) in Haenam. 50% home-range measured by KDE was $21.8km^2$ (SD=26.9, n=5) in Anseong and $3.5km^2$ (SD=2.2, n=5) in Haenam, indicating a narrow home range in Haenam. During the winter season, both wetland and paddy field were mostly used as habitats in Anseong and Haenam. While the paddy field utilization rate was high in the daytime in Haenam, it was high in the nighttime in Anseong. By late winter, Haenam's day time paddy field utilization rate and Anseong's night time paddy field utilization rate increased.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.647-653
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• 2007

The ultimate objective of this study is to develop a reliable oxygen-enriched combustion techniques especially for the case of the flue gas recycling in order to reduce the $CO_2$ emissions from practical industrial boilers. To this end a systematic numerical investigation has been performed, as a first step, for the resolution of the combusting flame characteristics of lab-scale LNG combustor. One of the important parameters considered in this study is the level of flue gas recycling calculated in oxygen enriched environment. As a summary of flame characteristics, for the condition of 100% pure $O_2$ as oxidizer without any flue gas recycling, the flame appears as long and thin laminar-like shape with relatively high flame temperature. The feature of high peak of flame temperature is explained by the absence of dilution and heat loss effects due to the presence of $N_2$ inert gas. The same reasoning is also applicable to the laminarized thin flame one, which is attributed to the decrease of the turbulent mixing. These results are physically acceptable and consistent and further generally in good agreement with experimental results appeared in open literature. As the level of $CO_2$ recycling increases in the mixture of $O_2/CO_2$, the peak flame temperature moves near the burner region due to the enhanced turbulent mixing by the increased amount of flow rate of oxidizer stream. However, as might be expected, the flue gas temperature decreases due to presence of $CO_2$ gas together with the inherent feature of large specific heat of this gas. If the recycling ratio more than 80%, gas temperatures drop so significantly that a steady combustion flame can no longer sustain within the furnace. However, combustion in the condition of 30% $O_2/70% $ $CO_2$ can produce similar gas temperature profiles to those of conventional combustion in air oxidizer. An indepth analyses have been made for the change of flame characteristics in the aspect of turbulent intensity and heat balance.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.67-75
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• 2012

Carbon-dioxide capture and storage (CCS) process is consisted by capturing carbon-dioxide from large point source such as power plant and steel works, transporting and sequestrating captured $CO_2$ in a stable geological structure. During CCS process, it is inevitable of introducing impurities from combustion, capture and purification process into $CO_2$ stream. Impurities such as $SO_2$, $H_2O$, CO, $N_2$, Ar, $O_2$, $H_2$, can influence on process efficiency, capital expenditure, operation expense of CCS process. In this study, experimental apparatus is built to simulate the behavior of $CO_2$ transport under various impurity composition and process pressure condition. With this apparatus, $N_2$ impurity effect on $CO_2$ mixture transportation was experimentally evaluated. The result showed that as $N_2$ ratio increased pressure drop per mass flow and specific volume of $CO_2-N_2$ mixture also increased. In 120 and 100 bar condition the mixture was in single phase supercritical condition, and as $N_2$ ratio increased gradient of specific volume change and pressure drop per mass flow did not change largely compared to low pressure condition. In 70 bar condition the mixture phase changed from single phase liquid to single phase vapor through liquid-vapor two phase region, and it showed that the gradient of specific volume change and pressure drop per mass flow varied in each phase.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.354-374
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• 2016

This study explored spatiotemporal variability of water quality in correspondence with hydrometeorological factors in the five stations of Paldang Reservoir located in the Han River during 4 years from May 2012 to December 2015. Variability of basic water quality factors were largely related with seasonal fluctuations of hydrology. Temperature stratification occurred in the deep dam station, and prolonged hypoxia was observed during the draught year. Nitrogen nutrients were increased with decreasing inflow in which changing pattern of $NH_4$ reversed to $NO_3$ by the effect of treated wastewater effluent. Phosphorus increase was manifest during the period of high inflow or severe drought. Chl-a variation was reversely related with both flow change and AGP(algal growth potential) variations. Our study demonstrated that water quality variability in Paldang Reservoir was largely attributed to both natural and operational changes of inflow and outflow (including water intake) based on major pollution source of the treated wastewater (total amount of $472{\times}10^3m^3d^{-1}$) entering to the water system from watershed. In the process of water quality variability, meteorological (e.g., flood, typhoon, abnormal rainfall, scorching heat of summer) and hydrological factors (inflow and discharge) were likely to work dynamically with nutrients pulse, dilution, absorption, concentration and sedimentation. We underline comprehensive limnological study related to hydro-meteorolology to understand short- and long-term water quality variability in river-type large reservoir and suggest the necessity of P-free wastewater treatment for the effective measure of reducing pollution level of Paldang drinking water resource.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.535-547
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• 2021

Aggregate is an essential construction material, and the demand is increasing every year. Aggregate has different properties in each region, and it is difficult to supply it over long distances due to its quantity and weight. For the stabilization of aggregate supply and demand, regional aggregate resource surveys have been conducted since 1993 in Korea. In this study, an aggregate resource survey was conducted in Goyang City to understand the characteristics of aggregate distribution as part of the annual regional aggregate resource survey in 2020. Goyang City has a high mountainous area to the east, and the southwestern part shows a topography where a wide flatland develops. It has 18 small streams originated from the eastern mountainuos area and 1 large stream Han River. The drilling data shows that thickness of the Quaternary deposits tend to deepen toward the south. The aggregate reserves are relatively abundant, the depth of the aggregates are relatively deep. Changes in the depth of the Quaternary deposits and the amount of aggregate in Goyang are seems to be closely related to the activities of the Han River rather than the sedimentation characteristics from the upstream to the downstream of the small streams. This characteristics show a similar tendency to the distribution of aggregates in adjacent regions to the west coast in Korea. Therefore, the regions that close to west coast have a high probability of aggregate reserves around relatively large-scale streams flowing into the west coast.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.16-31
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• 2013

This study addresses how the main group of community ritual changed as the regional community changed during the period of Japan's colonial rule of Korea with emphasis on Gwanseongmyo in Jangchung-dong, Seoul. First, almost every regional community was changed because of city planning which was carried out by Japan in Korea for colonial exploitation and for the use of military bases. Mapo-dong and Seobinggo-dong were the appropriate examples. The city planning projects by the Japanese colonial government selected Jangchung-dong as the place of settlement of many Japanese people. The stream, Cheonggyecheon, made a border between the Korean and Japanese settlements and the traditional system of regional community in Jangchung-dong was changed and reorganized considerably. Second, the Japanese government used the rituals of regional community purposefully to combine them with the ceremony in the Japanese shrine. Those who supported Japan performed the regional rituals and tried to follow the policy of 'Rule of Culture' required by the Japanese colonial government. However, most regional rituals continued as they were before Japan's colonial rule of Korea without any change. Under this new trend the ritual of Gwanseongmyo was changed from the ritual for worshipping Guan Yu to that of the regional community. Last, the main groups that led the rituals of regional community were diversified during the period of Japan's colonial rule of Korea. In other words, the rituals of community used to be led by the families that lived in the region for generations before Japan's colonial rule of Korea. However, they were later led by various groups that emerged as a result of the colonial rule, urbanization, commercial development, regional differentiation, and so on. As an example,Yeongsinsa of Gwanseongmyo,which was the main group to lead the ritual of Gwanseongmyo, shows that the regional community rituals were extended to worshipping Guan Yu. The members of the main group to lead the ritual were pro-Japanese senior officials who were formerly military officers. This shows that the main groups leading the regional community rituals were further diversified.