• Journal of the Korean Society of Radiology
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• v.18 no.1
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• pp.1-9
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• 2024

Proton therapy is known for its superior treatment method due to Bragg peak. To enhance the therapeutic effects of protons, research has been conducted on distributing gold nanoparticles within tumors to increase the absorbed dose. While previous studies focused on handling gold nanoparticles at micrometer and nonometer scale, this study proposes a method to computationally estimate the effect of gold nanoparticles at the millimeter scale. The Geant4 toolkit was applied to computational modeling. Assuming a uniform distribution of water, similar to the human body, and gold nanoparticles, the concentration of gold nanoparticles was adjusted using density ratios. When the density ratio was 5%, the gain in absorbed energy due to gold nanoparticles was nearly twice that of the pure water phantom at the Bragg peak. As the density ratio increased, the gain in absorbed energy linearly increased. When gold nanoparticles were distributed in only one voxel at the Bragg peak, the energy of the protons affected only the neighboring voxels. However, in cases where gold nanoparticles were distributed over a wide area, the volume showing 95% of the maximum absorbed energy (9.46 keV) for the pure water phantom (9.95 keV) exhibited an improvement in absorbed energy over a region 16 times larger, and this region increased as the density ratio increased. Further research is needed to quantify the relationship between the density ratio of gold nanoparticles and the relative biological effect (RBE) in the millimeter scale.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.69-78
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• 2008

An integration study of watershed model(HSPF, Hydological Simulation program-Fortran) and reservoir water quality model (CE-QUAL-W2) was performed for the evaluation of turbid water management in Yongdam reservoir. The watershed model was calibrated and analyzed for flow and suspended solid concentration variation during rainy period, their results were inputted for reservoir water quality model as time-variable water temperature and turbidity. Results of the watershed model showed a good agreement with the field measurements of flow and suspended solid. Also, results of the reservoir water quality model showed a good agreement with the filed measurements of water balance, water temperature and turbidity using linkage of the watershed model results. Integration of watershed and reservoir model is an important in turbid water management because flow and turbidity in stream and high turbidity layer in reservoir could be predicted and analyzed. In this study, the integration of HSPF and CE-QUAL-W2 was applied for the turbid water management in Yongdam reservoir, where it is evaluated to be appliable and important.

• Proceedings of the ESK Conference
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• 1994.04a
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• pp.157-157
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• 1994

원자력발전소 운영의 중추적 역할을 담당하고 있는 운전원과 발전소시스템 사이에서 발생하는 인간공학적 요인(인적요인)은 다중방호벽의 존재와 자동화 기술의 확대에도 불구하고 원전의 가동 성 및 안전성을 위협하는 최대의 요인이다. 최근 원자력발전소 시스템에 고도화된 전자공학 및 인공 지능기술 등이 반영되고 있는 추세이나 이러한 기술의 도입이 운전원과의 복합적 상호작용관점에서 원전의 안전성과 효율성에 적합한가를 실험적으로 평가할 수 있는 실험평가기술의 확보가 필요한 실정이다. 한국원자력연구소에서는 차세대 주제어실의 설계 및 평가를 위한 실험적 자료의 생성 및 설계 대안의 평가를 위한 기술확보라는 목적을 가지고 1992년도부터 수행하고 있다. 1992년도(1차년 도)에는 새로운 주제어실에서 실험적으로 평가해야 할 평가항목을 구체화하였고, 4년간의 연구추진 내용을 설정하였다. 기존의 원자력산업계에서 요구하고 있는 인가/허가 요건, 사업자요건서, 인간 공학분야에서 제기하고 있는 문제점 등을 분석하여 10개의 실험평가항목을 도출하였으며, 실험평가 항목을 실제로 실험을 통하여 연구하기 위한 장비 및 설비 그리고 소요기술 등을 고려하여 연구방향을 설정하였다. 1993년도(2차년도)에는 차세대 주제어실의 특징을 규명하고 실험연구의 대상시스템을 설정하였다. 설정된 대상시스템을 기능별로 분석하여 설계변수를 도출하였으며, 인간공학 실험실의 구축에 필수적인 원자력발전소 시뮬레이터의 기능요건 및 실험실의 구성요건 등을 개발하고 있다. 3차년도부터는 인간공학실험을 수행하면서 자료분석체계의 개발, 원전직무 시나리오의 개발, 측정방법의 개발, 인간공학 실험실의 설계, 구축 및 검증, 평가기법 연구, 실시간 자료수집체계의 개발 등을 수행할 예정이며, 연구종료시점인 1996년도(5차년도)에는 원자력발전소 주제어실의 인간공학적 평가를 위한 실험 환경의 구축 및 실험평가기술의 확립이라는 목표가 달성된다.하는 것으로 간주된다. 2. KR 53234 10mg/kg 정맥투여후의 최고혈중농도는 1.14ug/ml, 반감기는 0.50hr, 분포용적은 2.2L이었다. 20mg/kg 경구 투여시의 최소 혈중 농도는 0.33 ug/ml, 소실반감기는 1.5시간, AUC는 0.942ug.hr/ml, 분포용적 11L, Ka는 3.05 $hr^{－1}$ 그리고 Cl는 5.3L/hr/kg이었다. 이는 KR 53170에서와 같이 매우 적은량이 흡수되고 배설되었다. 3. KR 53170의 혈청단백 결합율은 5-500 ug/ml 범위에서 78.7-86.2%이었고 KR 53234의 혈청단백결합율은 5-100 ug/ml 범위에서 79.6-71.2%이었다.이었다.tic techniques, and we have recently cloned two of the major subunits; some of the data will be presented.LIFO, 우선 순위 방식등을 선택할 수 있도록 확장하였다. SIMPLE는 자료구조 및 프로그램이 공개되어 있으므로 프로그래머가 원하는 기능을 쉽게 추가할 수 있는 장점도 있다. 아울러 SMPLE에서 새로이 추가된 자료구조와 함수 및 설비제어 방식등을 활용하여 실제 중형급 시스템에 대한 시뮬레이션 구현과 시스템 분석의 예를 보인다._3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하여 구한 결과 0.05 - 0.10 mm/hr 의 범위로서 이로 인한 강우손실량은 큰 의미가 없음을 알았다.재발이 나타난 3례의 환자를 제외한 9례 (75%)에서는 현재까지 재발소견을 보이지 않고 있다. 이러한 결과는 다른 보고자들과 유사한 결과를 보이고 있

• Journal of Korea Foresty Energy
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• v.23 no.1
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• pp.1-18
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• 2004

Effects of nitrogen and phosphorus fertilization on aboveground biomass and distribution of nutrient content in tree components were determined in adjacent 41-year-old plantations of Pinus rigida Miller and Larix kaempferi Gordon on a similar soil in Yangpyeong, Gyeonggi Province. Fertilizer was experimentally applied at the three levels [control(C), 200 N kg/ha+25 P kg/ha(LNP), and 400 N kg/ha+50 P kg/ha(HNP)] in June, 1996. The results obtained from this study were summarized as follows: Total aboveground biomass of P. rigida and L. kaempferi stands was 149, 145ton/ha for control, 166, 149ton/ha for LNP, and 152, 170ton/ha for HNP, respectively, and did not differ between the tree species. Aboveground biomass of P. rigida and L. kaempferi plantations were distributed as follows: stemwood>branch>stembark>foliage. Biomass of understory vegetation was 1,111kg/ha for P. rigida and 907kg/ha for L. kaempferi, and comprised 0.6～0.7% of the total aboveground biomass of the plantations. The concentrations of all nutrients(N, P, K, Ca, Mg) were generally higher in L. kaempferi than in P. rigida because of high nutrient uptake characteristics of Larix spp. Nutrient concentrations in tree components of P. rigida and L. kaempferi plantations were not significantly different among treatments, whereas they were significantly different between species and among tree components. The nutrient concentration in tree components of both tree species decreased in order of foliage>branch>stembark>stemwood. The contents of all nutrients were higher in the fertilized plots than in the control plots, generally the highest in LNP for P. rigida and in HNP for L. kaempferi. Total nutrient(N+P+K+Ca+Mg) contents of aboveground biomass were 703kg/ha for P. rigida and 869kg/ha for L. kaempferi, respectively.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.613-623
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• 2011

This study assessed the feasibility to apply Two-band and Three-band reflectance models for chlorophyll-a estimation in turbid productive waters whose scale is smaller and narrower than ocean using a high spatial resolution image. Those band ratio models were successfully applied to analyzing chlorophyll-a concentrations of ocean or coastal water using Moderate Imaging Spectroradiometer(MODIS), Sea-viewing Wide Field-fo-view Sensor(SeaWiFS), Medium Resolution Imaging Spectrometer(MERIS), etc. Two-band and Three-band models based on band ratio such as Red and NIR band were generally used for the Chl-a in turbid waters. Two-band modes using Red and NIR bands of RapidEye image showed no significant results with $R^2$ 0.38. To enhance a band ratio between absorption and reflection peak, We used red-edge band(710 nm) of RapidEye image for Twoband and Three-band models. Red-RE Two-band and Red-RE-NIR Three-band reflectance model (with cubic equation) for the RapidEye image provided significance performances with $R^2$ 0.66 and 0.73, respectively. Their performance showed the 'Approximate Prediction' with RPD, 1.39 and 1.29 and RMSE, 24.8, 22.4, respectively. Another three-band model with quadratic equation showed similar performances to Red-RE two-band model. The findings in this study demonstrated that Two-band and Three-band reflectance models using a red-edge band can approximately estimate chlorophyll-a concentrations in a turbid river water using high-resolution satellite image. In the distribution map of estimated Chl-a concentrations, three-band model with cubic equation showed lower values than twoband model. In the further works, quantification and correction of spectral interferences caused by suspended sediments and colored dissolved organic matters will improve the accuracy of chlorophyll-a estimation in turbid waters.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.5
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• pp.398-405
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• 2012

PAHs(Polycyclic Aromatic Hydrocarbons) in coastal area and estuary adjacent to urban area and industrial activities region are mainly introduced into marine environment via atmosphere and river. This study which is evaluated the distribution characteristics of PAHs discharge from rivers and sewage disposal water which flowing into Ulsan bay, and were carried out in Jun of dry season and in Auguest of wet season, 2008. The water samples from eight main rivers and Youngyeon WWTP(Wastewater Treatment Plant) flowed into Ulsan bay were taken for analysis of dissolved PAHs. The range and mean values of dissolved PAHs concentrations showed 10.30 to 87.88 ng/L, its mean 36.94 ng/L in dry season and 10.30 to 69.57 ng/L, its mean 24.37 ng/L in wet season. The distribution of dissolved PAHs showd the high concentrations in the Gungcheoncheon which is flowed from urban and industrial area. The ranges and means values of the loading fluxes were estimated with 0.04 to 8.27 g/day, its mean 2.05 g/day in dry season, and 0.03 to 4.77 g/day, its mean 1.61 g/day, in wet season. The loading flux showed the highest value in Taewha river due to the high flow rate and the urban activity. The composition patterns of dissolved PAHs compound showed most of the trend occupying low molecuar weight PAHs than high molecular weight PAHs. These results were due to physical and chemical characteristics of PAHs compound, and were similar to those of other studies. The concentrations of dissolved PAHs in this study are lower than those of other studies, and the level of PAHs pollution appeared to be not serious in reverine waters of Ulsan coast.

• Analytical Science and Technology
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• v.19 no.3
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• pp.263-271
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• 2006

The levels of total PCBs, Co-PCBs and PCDD/Fs in the transformer insulation oil samples obtained using GC/ECD and HRGC/HRMS were ranged from N.D. to 77.3 ppm, from 0.0863 to 2.49 ppm and from N.D. to 0.00241 ppm, respectively. In terms of WHO-TEQ values, Co-PCBs and PCDD/Fs were ranged from 23.3 to 600 pgTEQ/g and from N.D. to 128 pgTEQ/g, respectively (${\Sigma}Co$-PCBs+PCDD/Fs concentration was calculated 24.4~728 pgTEQ/g). Although, the contribution of PCDD/Fs was below 12% in total TEQ concentration, it is suggested contamination of PCDD/Fs in transformer insulation oils. Among 10 samples, 4 samples showed higher concentration than 2 ppm (specific waste criterion of Korea) and Aroclor 1242, 1248, 1254 and 1260 was detected in samples as a single or mixture of Aroclor. It was shown reliable relationship between concentration of Co-PCBs and those of PCDD/Fs (p<0.003), however, was not shown between production year of transformer and concentration of PCBs. The distribution pattern of Co-PCB congeners showed that the ratios of mono-ortho substituted congeners were higher than non-ortho substituted congeners. Among that, PCB-118 congener was predominant. In addition, the OCDD congener was predominated in PCDD/Fs congeners as above 53%. Moreover, the congener pattern of Co-PCBs was similar to that of Aroclor as well as ambient air, which suggested that PCBs volatilization from transformer insulation oil affected the pattern of Co-PCBs in ambient air.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.87-98
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• 2016

During the period between July 3 and 27 of 2009, water samples were collected from the Russian coast at a depth of 30m from 26 stations (including Ulleung and Japan basins) onboard the Russian survey vessel R/V Lavrentyev following 4 lines (D, R, E, and A). The samples were analyzed for nutrients and chlorophyll a contents. All parameters exhibited higher values in warm waters than in cold waters ($NH_4:1.8-fold$, $PO_4:1.8-fold$, $SiO_2:1.2-fold$, and chlorophyll-${\alpha}$:1.9-fold), except nitrates, which was 1.4-fold higher in cold waters than in warm waters. The horizontal distribution of ammonia, phosphate, and chlorophyll-${\alpha}$ was very similar to each other and showed the highest values in the waters near Russia, where a upwelling influence of cold current and bottom water prevails, while relatively low distribution was observed at the Ulleung Basin. On the other hand, nitrates showed the highest concentration at the Ulleung Basin, which is under the direct influence of the Tsushima warm water, and showed a gradual decrease northward. The N/P ratio showed the highest value in the Tsushima middle water, rather than in the North Korean Cold Water, the Tsushima Warm Water was the primary source of nitrate flow into the East Sea. However, the average concentration of phosphate in the warm waters was < $0.2{\mu}M$, thereby limiting phytoplankton growth, while a high concentration of phosphate in cold waters showed a direct correlation with chlorophyll-${\alpha}$. The results of principal component analysis for the identification of primary factors that influence the marine environment showed that principal component I was water temperature and principal component II was influenced chlorophyll-${\alpha}$ and nutrients. Therefore, Study area has greatest influenced by water temperature, and clearly distinct cold and warm water regions were observed in the East Sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.225-237
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• 1990

Various chemical constituents were measured from April to August 1988 at the down-ward 20 stations of Keum River, which is located in the Midwest of Korea, to understand the characteristics of water quality with respect to spatio-temporal variations of each constituent. The 24-hrs continuous measurements with 2-hrs interval were made simultaneously at station 2 near the estuary weir and station 9(Ganggyeong) of 35 km upstream from the weir in April. By the results observed for one day in April at station 2, salinity has a range of $7.88\~22.14\%_{\circ}$ and its temporal variability is identical to the pattern of tidal cycle in the neigh-bouring Kunsan Harbor. However, turbidity shows relatively high values only at an interval of 4~5 hours after the lowest salinity time, though hourly fluctuation of pH is very small. Silicate and dissolved inorganic nitrogen have inversively linear correlationships with salinity, implying the concentration of the two nutrients strongly regulated by estuarine mixing of sea and river waters. In contrast, phosphate sustains roughly a constant level over a wide salinity range and distinctly lower values than those corresponding to nitrate in the oceans. Such distributions of phosphate have been observed in some estuaries, and interpreted as driven by removal of dissolved phosphate into bottom sediments and the bufforing of phosphate by particulate matter. COD values at station 2 are relatively high in day-time(particularly afternoon) and in high-salinity periods. At station 9, saltwater intrusion was never found but water level changed to the extent of 2.5 m for one day. Although each parameter at this station exhibits very slight variations in their abundance for 24 hours compared with station 2, the contents of COD, silicate and ammonia are significantly higher than at station 2. Concentration of suspended matter is relatively high in the brackish water region up to $\~20$ km above the river mouth, probably due to strong tidal stirring of the bottom de-posits. Also, relatively high pH, COD and $O_2$ saturation at the upward stations of $40\~50$ km from the weir are presumably attributable to active photosynthesis of plants in the region. In general, COD and nutrients except phosphate are higher values at the upper stations than in the estuary zone, and show the highest abundances in July nearly at all stations. Finally, in the estuarine region tidal mixing of sea-river waters seems to be an important factor controlling the distributions of turbidity, COD, silicate and nitrate as well as salinity. However, water quality in the upward fresh-water zone is remarkably variable according to months or seasons.

• Journal of Korea Water Resources Association
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• v.54 no.3
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• pp.167-179
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• 2021

In order to characterize the mixing process of confluence for understanding the impacts of a river on the other river, it has been crucial to analyze the spatial mixing patterns for main streams depending on various inflow conditions of tributaries. However, most conventional studies have mostly relied upon hydraulic or water quality numerical models for understanding mixing pattern analysis of confluences, due to the difficulties to acquire a wide spatial range of in-situ data for characterizing mixing process. In this study, backscatters (or SNR) measured from ADCPs were particularly used to track sediment mixing assuming that it could be a surrogate to estimate the suspended sediment concentration. Raw backscatter data were corrected by considering the beam spreading and absorption by water. Also, an optical Laser diffraction instrument (LISST) was used to verify the method of acoustic backscatter and to collect the particle size distribution of main stream and tributary. In addition, image-based spatial distributions of sediment mixture in the confluence were monitored in various flow conditions by using an unmanned aerial vehicle (UAV), which were compared with the spatial distribution of acoustic backscatter. As results, we found that when acoustic backscatter by ADCPs were well processed, they could be proper indicators to identify the spatial patterns of the three-dimensional mixing process between two rivers. For this study, flow and sediment mixing characteristics were investigated in the confluence between Nakdong and Nam river.