• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.516-531
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• 2015

In this study, a software module to predict the effectiveness of vegetation buffer strip (VBS) has been developed for using with Chemicals, Agricultural Management and Erosion Losses (CAMEL), a distributed watershed model. Most basic functions for the VBS module are same as CAMEL except functions newly developed to implement sedimentation enhancement by vegetation and level spreaders. For verification of the VBS module, sensitivity analyses for length, roughness, soil and vegetation type of VBS were carried out using a test grid cell. The surface discharge of sediment are highly sensitive to the roughness coefficient of VBS. The removal efficiencies of VBS for the surface discharges of sediment and TP are generally high regardless of environment changes. The surface discharges of TOC and TN are highly sensitive to the length and soil of VBS. The removal efficiencies of VBS for the surface discharges of TOC and TN are generally lower than those of sediment and TP. The newly developed VBS module reasonably simulates the removal efficiencies of surface discharges that vary according to the environment changes. It is expected that this VBS module can be used for evaluating the effectiveness of VBS-based best management practices to be applied to reduce pollution discharges from various non-point sources.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.431-444
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• 2020

The relationship between dam construction and water quality has recently come to be considered an important issue. A dam is a physical factor which causes changes to the river system around it. Considering these points, this study was conducted to obtain basic data by analyzing the relationship between water level fluctuations and water quality parameters in the short-term. In terms of methodology, the new construction of the Yeongju Dam (M5) in 2016 was divided into Stage 1 as the lotic system and Stage 2 as the lentic system, with four years in each period, and the water level fluctuations and water quality were analyzed using official data. As a result of this study, M5, a stagnant area in which organic matter and nutrients accumulate, was found to be an important factor in water quality management. In addition, the water level changed rapidly (0.9±0.2 m → 10.9±7.1 m) as the river environment condition was converted from the lotic system to the lentic system. In addition, water quality parameters such as BOD, COD, TOC, and Chl-a significantly changed in the short-term. Further, since the transport of organic matter and nutrients occurred well in the lotic system, sedimentation was expected to be dominant in the lentic system. Therefore, it was determined that when the river flow is blocked, autochthonous organic matter is an important factor for long-term water quality management in the future. This process can increase the trophic state of the water body. As a result of this study, the TSI_KO value was converted from mesotrophic in Stage 1 to eutrophic in Stage 2. Eventually, short-term changes in the river environment will affect not only changes in water level but also changes in water quality. Thus, a comprehensive and strategic approach is needed for long-term water quality management in the future.

• Journal of Environmental Science International
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• v.29 no.11
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• pp.1055-1064
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• 2020

In this research, heavy metals and T-P removal characteristics of plated wastewater are derived using BPC(Break Point Chlorination) process. AA sedimentation pond outflow(Influence) was evaluated for the removal efficiency of heavy metal(Ni) and T-P at a reaction time of 25 minutes by NaOCl input volume(9, 11, 13 and 15 mL). In the case, the higher the NaOCl input volumes, the higher the ORP values were maintained and the higher the removal efficiency tended to be. On the other hand, T-P was judged to have a low relationship between the ORP value and the removal efficiency. In addition, the efficiency of removal heavy metals and T-P in the plated wastewater by injecting 10 mL, 15 mL, 20 mL and 25 mL NaOCl, increased as the amount of NaOCl injected increased, the amount of NaOH input for pH increased. It was found that suspended solid in effluence also increased. It was also observed that the color of the plating wastewater changed from yellowish green to green to charcoal gray to black as the amount of NaOCl injected increased. Treatment characteristics of the reaction time, the longer the reaction time with the substance to be treated after the input of NaOCl, the more the heavy metal removal efficiency tended to increase. Through XRF analysis of the sludge, the constituents in the sludge such as NaCNO, CNCl, Na₃PO₄, CrO₄, 2Na₂CrO₄ and 2NaNO₃ will be analyzed in detail, and the mechanisms of the reaction between the plated wastewater and the complex compound will be elucidated.

• Analytical Science and Technology
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• v.13 no.4
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• pp.403-411
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• 2000

This study described a method of thermoluminescence dating of pottery shards using subtraction method. TL measurement was achieved using two different types of samples prepared by quartz inclusion method and fine-grain technique. Fine grains (size range: $5-10{\mu}m$) were separated by suspending grounded pottery samples into acetone solution and sedimentation quantitatively. In quartz inclusion method quartz grains in the size range of 90 to $125{\mu}m$ diameter were obtained by extracting the quartz crystals embed in the pottery shards and etching them with 1.0 M HF solutions. The archaeological dose of both the quartz and fine grains was determined from the dose calibration curves obtained from sequential irradiation of $^{137}Cs$ gamma and $^{241}Am$ alpha source to the samples and TL measurement of natural samples, in which the alpha dose of 4.60 Gy for the Packjae pottery was obtained using subtraction method. Annual alpha dose rates ($3.05{\pm}0.11$ mGy/yr.) were determined by the analysis of U, Th contents in the pottery shards and evaluation of the values with Bell's equation. Dividing the alpha dose accumulated in the pottery shards by the annual alpha dose rate, we found age of approximately $1508{\pm}80$ years B.P. (AD. ca. 492 yr.) for the Packjae pottery. It matches well with the archeological age estimate (middle of 5th century) within 10 percent uncertainty and thereby conforms the age of the pottery sample.

• Journal of Korean Neurosurgical Society
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• v.61 no.1
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• pp.81-88
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• 2018

Objective : Spondylitis is often chemotherapy resistant and requires long-term treatment. Without adequate chemotherapy, the outcome can be fatal or result in severe neurologic damage. Therefore, differentiating the etiology of spondylitis is very important, particularly in spontaneous cases. As the prevalence of tuberculosis in Korea has decreased in recent years, updated clinical research about spondylitis is warranted. Methods : From April 2010 to March 2016, data from spondylitis patients were collected retrospectively. In total, 69 patients (51 with pyogenic spondylitis and 18 with tuberculous spondylitis) were included. Clinical data, laboratory findings including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level, measurements of Cobb angles at the initial and final follow-up, and radiologic features on magnetic resonance imaging (MRI) scans were evaluated. To test differences between the pyogenic and tuberculous groups, numerical data were compared using the student's t-test and Mann-Whitney U test, and categorical data were compared using the chi-square test and Fisher's exact test. Results : The patients' mean age was 60.0 years. Male sex was slightly predominant (56.5%). There was no difference in mean age and sex between the two groups. The pyogenic group had a relatively higher proportion of immunocompromised patients. The peak CRP value was higher in the pyogenic group than in the tuberculous group (14.08 mg/dL and 8.50 mg/dL, respectively, p=0.009), whereas the ESR was not significantly different between the groups (81.5 mm/h and 75.6 mm/h, respectively, p=0.442). Radiologically, the presence of disc space sparing and vertebral body collapse differed between the groups. In the tuberculous group, the disc was more commonly preserved on contrast-enhanced MRI (50% and 23.5%, respectively, p=0.044), and vertebral body collapse was more common (66.6% and 15.7%, respectively, p<0.001). The mean length of hospitalization was longer in the pyogenic group (56.5 days and 41.2 days, respectively, p=0.001). Four mortality cases were observed only in the pyogenic group. The most commonly isolated microorganism in the pyogenic group was Staphylococcus aureus(S. aureus) (methicillin susceptible S. aureus and methicillin resistant S. aureus [MRSA] in 8 and 4 cases, respectively). Conclusion : The clinical and radiological manifestations of spontaneous spondylitis differ based on the causative organism. Pyogenic spondylitis patients tend to have a higher CRP level and a more severe clinical course, whereas tuberculous spondylitis patients present with destruction of the vertebral body with disc sparing more frequently. The presence of MRSA is increasing in community-acquired spondylitis cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.615-623
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• 2016

This study was conducted to identify differences between qualities of health related to quality of life according to the general characteristics of ankylosing spondylitis patients. Overall, 275 patients who were older than 19 years, drug-maintained for over 4 weeks from Jan 13th to Feb 12th and diagnosed as ankylosing spondylitis at C university hospital participated in this study. Collected data were analyzed through descriptive statistics, t-tests, ANOVA, Scheffe's-test and multiple regression. The results of the present study revealed that Age (p=.008), Job (p<0.001), Number of comorbidity (p<0.001), Surgery for Ankylosing Spondylitis (p=0.002), Disease duration after onset symptom (p=0.010), Disease duration after diagnosis (p=0.027), Alcohol drinking (p=0.002) and Erythrocyte sedimentation rate (p=0.049) were meaningful factors to the quality of health-related life for ankylosing spondylitis patients, and multiple regression analysis showed that level of education, income, comorbidity and alcohol consumption was a significant variable. In conclusion, the results of this study indicated that, to improve quality of life, arbitration programs for improving general characteristics and considering demographic social characteristics and clinical features need to be provided. Therefore, it is expected that the results of this study would be used as actual grounds to develop integrated arbitration programs.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.163-171
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• 2024

Changes in the soil layer on Dokdo are important both academically and with regard to sustainable conservation and utilization of the islands. Continuous investigation and observation are necessary, as the soil layer is essential to the growth of plants and, therefore, the islands' ecosystem. Such work was carried out for about 8 years using soil erosion measuring bars, which are durable and facilitate simple monitoring of changes in the soil layer. Each bar comprised a rod measuring 30~50 cm long and 1.5 cm in diameter, and the use of stainless steel afforded resistance to corrosion caused by sea breezes. Six measuring bars were installed in the soil layers of each of two islands, Dongdo and Seodo, and measurements were taken one to three times a year from 2014 to 2021. The field measurements indicate that soil was deposited on Dongdo but eroded on Seodo during the observation period. As the measuring bars on Dongdo were located in the central and lower parts of the island, the observed changes in the soil layer resulted mainly from sedimentation of material eroded by weathering or soil runoff from the upper part of the island. In contrast, the measurement locations on Seodo were located in the upper and central parts of the island, where soil erosion and runoff diminished the soil layer at the observation points.

• Journal of the Korean association of regional geographers
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• v.11 no.4
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• pp.453-462
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• 2005

The study deals with surface erosion patterns due to the development of cropland toward hillslope and hilltop in the Oncheon-gun, pyeongbuk province and Nampo city of west coast area in the North Korea, using Quick Bird satellite images with 60cm resolution. In North Korea, for national economic difficult after 1980 year, newly developed croplands have been along the gentle hillslope, in which it is possible for individual man power different from the tideland which needs large scaled man-power and equipment. The new croplands are named Darakbat(terraced farm with embankment) and Bitalbat(titled farm developed on the original hill slope), neighboring with orchard and grouped settlement in lower valley. For supplying agricultural water, irrigation ditches and temporal crop storages have been constructed, connecting Darakbat, Bitalbat and orchard. These cropland developments have caused surface erosion composed of 3 types such as pit, linear and headward erosion, together with rill and gully. Owing to poor management of cropland and irrigation system, topsoil erosion and, collapse and sedimentation of ditch and pool, caused the decrease of agricultural productivity. These analysis using Quick Bird images can suggest original raw data about geographical facts on North Korea agriculture and help to recover their agricultural system and plan future national unified land.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.9-20
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• 1991

The characteristics of the unconsolidated sediment in Gwangyang bay was analyzed from the core samples. The porosity of the sediment showed irregular variation with respect to the sedimentation depth, which indicated that sediment weight-induced consolidation was not significant. Numerical analysis for the mechanical and hydraulic behavior of the unconsolidated sediment due to the tidal sea level change was processed. Because of the delayed excessive pore pressure change in the very low permeable mud medium, the magnitude of the excessive pore pressure for the duration of the minimum sea level exceeded the total stress from the sea water weight, which resulted in the negative (tensional) effective stress below the top surface. The in-situ effective stress, obtained by superposing the tensional effective stress on the solid weight-induced compressive stress, was remained to be tensile (quick-sand condition) near the top surface of the mud deposit. The occurrence of the quirk-sand condition provided a theoretical evidence for the insignificant consolidation and the irregular porosity variation of the sediment. When the sand is distributed on the top surface of the mud layer, the quick-sand condition occurred below the sandy mud layer and the downward movement of sand particles was facilitated.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.506-510
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• 2004

Purpose: We investigated whether Tc-99m MIBI imaging is useful to predict the response of drug treatment in patients with rheumatoid arthritis. Materials and Methods: 24 patients (15 women and 9 men, age $49{\pm}12$ year) rheumatoid arthritis and treated with disease modifying antirheumatic drugs (DMARDs) were included in this study. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured, and Tc-99m MIBI scan was obtained before drug treatment. Quantitative analysis of uptake in diseased joints was performed and expressed as joint-to background ratio (J/B) and percent retention (%R) of Tc-99m MIBI. Clinical symptoms were evaluated and graded from 0 (no) to 3 (severe) regarding to presence of tenderness and swelling. Results: J/B of the diseased joints were significantly correlated with ESR and CRP (p<0.05). A highly significant correlation was found between the improvement of clinical symptoms and %R of Tc-99m MIBI (p<0.05). Conclusion: The results demonstrate that Tc-99m MIBI scan may be used to predict the therapeutic response in patients with rheumatoid arthritis.