• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.516-520
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• 2008

There are many water treatment plants built over couple of decade ago in Korea. For most of those plants, they are required a countermeasure to cope with the deterioration caused from the superannuated facilities and the objective materials change of water treatment from inorganic particles like clay to algae particles due to eutrophication of lake and reservoir. A series of field and laboratory experiments was performed to investigate the feasibility of DAF hybrid process and the variation of particle characteristics by applying the additional DAF unit in conventional water treatment processes. On the basis of this experiments, the DAF was effective as an additive process in filtration basin (DAF-CSF combination processes). Using DAF-CSF combination process, the efficiency of stable particle removal can be achieved to produce the safe drinking water.

• Geomechanics and Engineering
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• v.38 no.3
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• pp.307-317
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• 2024

To get a better understanding of the effect of drying-wetting cycles (DWC) on the mechanical behaviors of silty clay hiving different initial moisture content (IMC), the direct shear tests were performed on sliding band soil taken from a reservoirinduced landslide at the Three Gorges Reservoir area. The results indicated that, as the increasing number of DWC, the shear stress-displacement curves type changed from strain-hardening to strain-softening, and both the soil peak strengths and strength parameters reduced first and then nearly remain unchanged after a certain number of DWC. The effects of DWC on the cohesion were predominated that on the internal friction angle. The IMC of 17% is regarding as the critical moisture content, and the evolution laws of both peak shear strength and strength parameters presented a reversed 'U' type with the rising of the IMC. Based on it, a strength deterioration evolution model incorporating the influence of IMC and DWC was developed to describe the total degradation degree and degradation rate of strength parameters, and the degradation of strength parameters caused by DWC could be counterbalanced to some extent as the soil IMC close to critical moisture content. The microscopic mechanism for the soil strength caused by the IMC and DWC were discussed separately. The research results are of great significance for further understanding the water-weakening mechanicals of the silty clay subjected to the water absorption/desorption.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.11
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• pp.613-625
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• 2017

For two agricultural reservoirs that are rented for fishing spots, benthic nutrient fluxes experiment were performed two times with two sediments from fishing-effective zone and one sediment from fishing-ineffective zone using laboratory core incubation in oxic and anoxic conditions. During benthic nutrient fluxes experiment, the changes in DO, EC, pH, and ORP in the supernatant were not significantly different between fishing-effective zone and fishing-ineffective zone, and were similar to the sediment-hypolimnetic diffused boundary layer in agricultural reservoir. Except for $NO_3{^-}-N$, more benthic nutrient fluxes of $NH_4{^+}-N$, T-P, and $PO{_4}^{3-}-P$ from sediment to hypolimnetic was measured in anoxic than in oxic conditions (p<0.05). As the DO concentration in hypolimnetic decreases, the microorganism-mediated ammonification is promoted, the nitrification is suppressed, and finally the $NH_4{^+}-N$ diffuses out from sediment to hypolimnetic. Also, the diffusion of T-P and $PO{_4}^{3-}-P$ from sediments to hypolimnetic is accelerated through the dissociation of the phosphorus bound to both organic matters and metal hydroxides. The difference in the benthic nutrient diffusive fluxes between fishing-effective zone and fishing-ineffective zone was not statistically significant (p>0.05). Therefore, it was found that fishing activities did not increase the benthic nutrient diffusive fluxes to a statistically significant level. Due to the short fishing activities of 10 years and the rate-limited diffusion of the laboratory core incubation, the contribution of fishing activities on sediment pollution is estimated to be low. No significant correlation was found between the total amount of nutrients in sediment and the benthic nutrient diffusive fluxes in both aerobic and anaerobic conditions. Therefore, nutrients input from various nonpoint sources of watersheds are considered to be a more dominant factor rather than fishing activities in water quality deterioration, and both aeration and water circulation in hypolimnetic were required to suppress the anoxic environment in agricultural reservoirs.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.115-128
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• 2008

Various human activities such as the Urbanization and Industrialization are estimated the main factors to pollute the stream. Now days, numerous studies are carried out for managing non-point sources which have un-effect on water quality of streams by land-use and livestock. In case of Korea, a matter of concern that the management of Pal dang reservoir - the main water resources of the national capital region - has been occurring. Especially, large-scale constructed-wetlands are planned and constructed at the end of Kyoung-an stream. Additionally a lot of sewage treatment plants are newly installed and extended in this watershed. According to these efforts, water quality of Kyoung-an stream is predicted that would be improved. But the more detail and scientific analysis should be carried out for the water quality improvement, because, existing water quality improvement projects are not involved to analyze root of water quality deterioration and improvement plans. Therefore, this study aims to select suitable areas for constructed-wetlands and to calculate size of the constructed-wetlands for water quality improvement in Kyoung-an stream through the geographical pollutant distribution analysis and land-use pattern analysis by high resolution satellite image and suitable area analysis of constructed-wetlands by GIS(Geographic information system). The progress of this study is (1) to select maximum pollutant loaded area by geographical analysis based on water quality data, (2) to analyze land-use patterns using high resolution satellite image, (3) to select suitable areas of constructed-wetlands, (4) to calculate area and volume of chosen constructed-wetlands using GIS. Basically, sizes of constructed-wetlands are induced through the constructed-wetlands design index based on treatment ratio(provided by Korea Water Resources Corporation). As a result of this study, two areas are selected to construct constructed-wetlands. One of the area was $127,586m^2$ near by Yong-in sewage treatment plant, and the other area was $1,647m^2$ near by Ju-buk stream and Dae-dae stream.

• Journal of Haehwa Medicine
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• v.10 no.1
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• pp.453-469
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• 2001

This study attempted to analyze the contents of the research papers concerning the diagnosis and treatment of Alzheimer-type dementia presented in the magazine of Chinese Medicine published in China over the period between 1998 and 2000. As a result, the following conclusion was drawn: 1. The Chinese medical category of Alzheimer-type dementia includes amnesia, dementia, stupidity, depression symptom complex, insanity and the like and uses the as the criterion for diagnosis and treatment effect evaluation. 2. The clinical symptoms of Alzheimer-type dementia include lowered intelligence, deterioration of memory, understanding and judgemental power, retardation of the reaction, emotional changes, character changes, behavioral changes and the like and are divided into mild, medium and serious according to the degree of symptom. 3. From the perspective of Bon-Heo-Pyo-Shil(state of deficient vital essence and excessive pestilential vapor), the pattern of Byun-Sung(identification) is divided into deficiency symptom complex, excessive symptom complex and indiscernible fullness and emptiness. The deficiency symptom complex includes deficiency of the liver and kidney, deficiency of essence of the kidney, deficiency of the reservoir of marrow and the like. The excessive symptom complex includes internally blocked stagnant blood, blocking of the passageway due to turbid phlegm, blood stasis due to stagnation of chi, and the like. The indiscernible fullness and emptiness symptom complex includes the deficiency of essence of kidney, blocking of the passageway due to stagnant phlegm, blood stasis due to the deficiency of kidney, blood stasis due to the deficiency of heart and the like. 4. The therapeutics and' prescription of Alzheimer-type dementia include the following: Bo-Shin-Ik-Su-Tang for tonifying the kidney, replenishing the marrow and plugging the essence; Ki-Guk-Ji-Hwang-Hwan-Ga-mi for reinforcing the vital essence of the liver and kidney; Kwi-Bi-Tang-Hap-Yang-Shim-Tang for invigorating the functioning of the spleen and nourishing the heart; Hyel-Bu-Chuk-Eo-Tang-Ga-Mi for activating the blood and resolving the stagnancy of the blood; Bo-Yang-Hwan-Oh-Tang for replenishing chi, activating the blood and resolving the stagnancy of the blood; Beoh-Kwang-Mong-Sung-Tang for invigorating the functioning of the spleen, replenishing the kidney, resolving the phlegm and enlivening the brain; n-Dam-Tang-Ga-Mi for invigorating the functioning of the spleen, replenishing chi, and removing the phlegm and unclogging the passageway); Se-Shim-Tang-Ga-Mi for removing the stagnancy of the liver and resolving the phlegm; and the like. 5. The research papers on, the medication cases of Alzheimer-type dementia understand the pathology of Alzheimer-type dementia from a consistent perspective. They view the pathology of Alzheimer-type dementia as the disease of Bon-Heo-Pyo-Shil(state of deficient vital essence and excessive pestilential vapor) with the combination of the deficiency of essence of the kidney, the deficiency of the brain marrow, blood stasis and blocked phlegm and the like and recommend the prescription of using Bo and Sa simultaneously for treating Alzheimer-type dementia. 6. The research papers on the medication cases of Alzheimer-type dementia reported that the use of creative prescriptions such as Si-Sam-Hang-Ji-Tang, Ji-Yung-Tang, Ka-Mi-Yunh-Ji-Hwan, Ja-Sin-Hwal-Hyel-Tang, Kal-Chang-Ik-Ji-Tang, Ho-Su-Bok-Ji-Tang, Kun-Noe-Ok-Ji-Hap-Je and the like led to the average high efficacy of 85.5%.