• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.601-608
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• 2008

The objective of this study was to evaluate the effect of ozonation as pretreatment on the removal of dissolved or biodegradable organic matter(DOM or BOM), the variance of DOM fractionation, and microbial regrowth by pilot-scale granular activated carbon processes in which adsorption and biodegradability was proceeding due to long time operation. Regardless of point of ozonation applied, GAC processes with ozonation(i.e., Ozonation combined with GAC Filter-adsorber; Pre O$_3$ + F/A, Ozonation combined with GAC adsorber; Post O$_3$ + GAC) compared with GAC processes without ozonation(i.e., GAC Filter-adsorber; F/A, GAC adsorber; GAC) removed approximately 10 to 20% more of DOC, hydrophilic DOM(HPI), BDOC and AOC after long period of operation that biological activity was assumed to happen. Ozonation was not found to have a significant effect on the removal of DOC, but caused the decrease of AOC by approximately 20%. It was found that the fixed bacterial biomass on GAC media did not show a significant difference between the GAC with ozonation and GAC without ozonation as pre-treatment, whereas the HPC of column effluent was more biostable at Post O$_3$ + GAC compared with F/A or GAC.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.207-215
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• 2006

This study evaluated the effect of ultrasonic irradiation on reducing membrane fouling for the treatment of chemically treated leachate and biologically treated leachate. The experiments on improvement of membrane flux according to the membrane types(MF and UF) and membrane materials were performed with changing frequency(40 kHz and 120 kHz) and intensity(200 W and 400 W) of ultrasound in ultrasonic membrane separation apparatus which ultrasound can be periodically irradiated. Additionally, the effect of dual frequency ultrasound which 40 kHz md 120 kHz are irradiated simultaneously was evaluated. The improvement of membrane flux by periodical ultrasound irradiation was higher in microfiltration(MF) membrane than in ultrafiltration(UF) membrane. It was sustained more in the MF membrane of polyvinylidene fluoride(PVDF) than in that of polysulfon(PS). Ultrasonic improvement of membrane flux was different depending on the characteristics of target wastewater. It was sustainably maintained without reclogging using dual frequency ultrasound although the improvement of membrane flux was lower.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.197-206
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• 2006

This study evaluated the effect of ultrasonic irradiation on improving the flux and cleaning efficiency in membrane process which is widely applied for the treatment of landfill leachate. The experiments on improvement of membrane flux according to the types of membranes(hallowfiber microfiltration, MF and tubular ultrafiltration, UF) were performed with changing frequency($40{\sim}120$ kHz), intensity ($200{\sim}500$ W) and irradiation time of ultrasound as well us operation pressure($0.1{\sim}2.3kg/cm^2$). Membrane was fouled for the first 50 min with primary treated leachate and then the change in flux according to ultrasonic irradiation period was observed for 70 min. Parameters influenced to the recovery ratio corresponding the net flux on pure water and to the enhancement ratio applied after ultrasonic irradiation on the flux were analyzed. In same condition, the flux was improved in proportion to ultrasonic intensity while the improvement of flux was inversely proportional to ultrasonic frequency. The cleaning effect of membrane was delayed and reduced when operation pressure of membrane was high. The recovery ratio and enhancement ratio for $0.1{\mu}m$ MF membrane were 10% and 500%, respectively while those were maximized at $75{\sim}98%\;and\;40{\sim}50%$ for UF membrane for 10,000 and 100,000 MWCO, respectively. In conclusion, it was confirmed that ultrasonic cleaning using mechanical vibration is alternative to water or chemical cleaning for improving membrane flux.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1035-1042
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. At S and B Water Treatment Plant, GAC is used in place of granular media in conventional rapid filters(GAC Filter-Adsorber) for removal of Disinfection By-products(DBPs). The primary focus of this study is on the performance of existing filter-adsorber, and their operation. It was found that F/A process removed turbidity as effective as sand system. The ratio of Hydrophobic DOM (HPO) and hydrophilic DOM (HPI) fraction in the raw water at S and B WTP was similar. Filter Adsorber presented earlier DOC breakthrough and steady state condition which was contributed by biodegradation during operation period. The removal efficiency of DBPs were used to evaluate the filter performance. The DBPs concentration of F/A treated water was below treatment goal level (THM < $80\;{\mu}g/L$, HAA < $60{\mu}g/L$). The removal efficiency of THM decreased rapidly during operation period. However, HAA were removed steadily regardless of the influent concentration of HAA. These results indicate that the removal of THM depend upon the adsorption mechanism while the removal of HAA depend upon biodegradation as well as adsorption. The decrease of adsorption capacity and characteristic value of GAC may be attributed to the effect of high organic loading, residual free chlorine, coagulants, manganese oxidants and frequently backwashing. This study has confirmed that Filter adsorber process can be considered as effective alternatives for the removal of DBPs, especially HAA.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.69-75
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• 2009

The characteristics of disinfection and organic removal were investigated with pulse UV lamp in this study. The intensity and emission wavelength of pulse UV Lamp were compared with low pressure UV lamp. The emission spectrum range of pulse UV lamp was between 200 and 400 nm while the emission spectrum of low pressure UV lamp was only single wavelength of 254nm. 3 Log inactivation rate of B. subtilis spore by pulse UV and low pressure UV irradiation was determined as $44.71mJ/cm^2$ and $57.7mJ/cm^2$, respectively. This results implied that wide range of emission spectrum is more effective compared to single wavelength emission at 254nm. 500ng/L of initial 2-MIB concentration was investigated on the removal efficiency by UV only and $UV/H_2O_2$ process. The removal efficiency of UV only process achieved approximately 80% at $8,600mJ/cm^2$ dose. 2-MIB removal rate of $UV/H_2O_2$ (5 mg/L $H_2O_2$) process was 25 times increased compared to UV only process. DOC removal efficiency for the water treatment plant effluent was examined. The removal efficiency of DOC by UV and $UV/H_2O_2$ was no more than 20%. Removal efficiency of THMFP(Trihalomethane Formation Potential), one of the chlorination disinfection by-products, is determined on the UV irradiation and $UV/H_2O_2$ process. Maximum removal efficiency of THMFP was approximately 23%. This result indicates that more stable chemical structures of NOM(Natural Organic Matter) than low molecule compounds such as 2-MIB, hydrogen peroxide and other pollutants affect low removal efficiency for UV photolysis. Consequently, pulse UV lamp is more efficient compared to low pressure lamp in terms of disinfection due to it's broad wavelength emission of UV. Additional effect of pulse UV is to take place the reactions of both direct photolysis to remove micro organics and disinfection simultaneously. It is also expected that hydrogen peroxide enable to enhance the oxidation efficiency on the pulse UV irradiation due to formation of OH radical.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.5
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• pp.559-569
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• 2007

The purposes of this study were to find the main foulant of membrane and the optimal chemical cleaning method for MF(microfiltration) drinking water treatment system using D dam water as water source. The MF pilot plant which can treat maximum $500m^3/d$ consisted of 3 racks and was operated for 10 months under various operation conditions. After 10 months operation, $1^{st}$ and $2^{nd}$ rack of membrane pilot plant system were cleaned chemically and the degree of the restoration of the fouled membrane in terms of the pure water flux was detemnined. Inorganic compounds which contained in chemical cleaning waste was analyzed by Inductively Coupled Plasma (ICP). One membrane module for 3rd rack was disjointed and membrane fouling materials, especially inorganic compounds were investigated by Electron Probe Microanlysis (EPMA) to elucidate the reason of TMP increase. And also, the various chemical reagents (1N HCl or $H_2SO_4$, oxalic acid as acid and 0.3% NaOCl as alkali) were tested by combination of acid and alkali to determine the optimal chemical cleaning method for the MF system using micro-modules manufactured using the disjointed module. It was verified that the inside and outside of membrane module was colorized with black. As a result of the quantitative and semi-qualitative analysis of membrane foulant by ICP, most of inorganic foulant was manganese which is hard to remove by inorganic acid such as HCI. Especially, it was observed by EPMA that Mn was attached more seriously in inside surface of membrane than in outside surface of that. It was supposed that Mn fouling in inside surface of membrane might be caused by the oxidation of soluble manganese (Mn(II)) to insoluble manganese ($MnO_2$) by chlorine containing in backwashing water. The optimal cleaning method for the removal of manganese fouling was consecutive cleaning with the mixture of 1N HCl and 1% of oxalic acid, 0.3% NaOCl, and 1N HCl showing 91% of the restoration of the fouled membrane.

• Korean Journal of Environment and Ecology
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• v.12 no.2
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• pp.119-130
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• 1998

The purposes of this study were to investigate vegetation structure and to present management plan of mountain type green space in Kangwhado, Inchon. The actual vegetation in survey sites(11,331ha) was divided into 19 community types. It was consisted of secondary forest(92.32%) which was Quercus acutissima, Pinus densiflora-Q. acutissima, and Q. mongolica community so on. Artificial planting forest area, such as Robinia pseudoacacia and Pinus rigida forest and others, was 5.40%(612ha) and it was less than cases in other cities in the Metropolitan area. According to the classification by TWINSPAN, 57 survey plots were divided into seven community types; P rigida(community A), Q. acutissima(community B) P. densiflora-Q. acutissima(community C), Q. acutissima-P. densiflora (community D), P. densiflora-Carpinus laxiflora-Q. serrata-Q. acutissima(community E), Q. serrata-Q. mongolica(community F), and Zelkova serrata-Acer mono(community G). From this result, ecological succession trend of vegetation in this area seems to be change from P. densiflora forest through Q. acutissima forest to Q. mongolica, Q. serrata, and C. laxiflora forest. It was similar to the ordinary successional trend of temperate deciduous forest in middle area, Korea. In addition, this study area was showed acid soil(pH 4.17). Therefore, there is a need for managing the soil environment for effective vegetation management.

• The Journal of the Korean bone and joint tumor society
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• v.7 no.2
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• pp.41-50
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• 2001

Purpose : To investigate biochemical markers for osteosarcoma, activities of deoxyribocuclease(DNase), ribonuclease(RNase), 5'-nucleotidase, alkaline phosphatase and amylase were determined in the osteosarcoma tissue and serum of patients with osteosarcoma. Also studied were DNase, RNase in osteosarcoma tissue, isolating the enzymes from the sarcoma tissue and investigating the sarcoma specific enzymes. Materials and Methods : The experimental tissue and serum were obtained from twelve patients with osteosarcoma. The control group were obtained from the normal healthy tissue of the same patients. The tissue were centrifugalized to obtain extracts. The extracts were analized for the estimation of nucleic acid, protein contents and enzyme activities. And then each enzymes were isolated and analized by DEAE-cellulose chromatography and estimated for activities. Result : Activities of acid DNase, RNase, 5'-nucleotidase and alkaline phosphatase were significantly increased in osteosarcoma tissue. Neutral RNase in osteosarcoma tissue was shown to bo highly active, exhibiting secretory form of RNase inhibitor associated with the RNase was also increased. In the serum of patients with osteosarcoma, RNase activity was significantly increased. DEAE-cellulose column chromatographical analysis revealed that acid DNase was isolated as a single enzyme and neutral RNase as five isozymes in osteosarcoma tissue. Conclusion : The results indicated that combination of these enzymes could be used as markers for osteosarcoma. The results indicated that acid DNase and neutral RNase might play a role in genesis of sarcoma and suppression of sarcoma.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.47-55
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• 2011

Hemorrhagic shock is a cause of one third of death resulting from injury in the world. Early diagnosis of hemorrhagic shock makes it possible for physician to treat successfully. The objective of this paper was to select an optimal classifier model using physiological signals from rats measured during hemorrhagic experiment. This data set was used to train and predict survival rate using artificial neural network (ANN) and support vector machine (SVM). To avoid over-fitting, we chose the best classifier according to performance measured by a 10-fold cross validation method. As a result, we selected ANN having three hidden nodes with one hidden layer and SVM with Gaussian kernel function as trained prediction model, and the ANN showed 88.9 % of sensitivity, 96.7 % of specificity, 92.0 % of accuracy and the SVM provided 97.8 % of sensitivity, 95.0 % of specificity, 96.7 % of accuracy. Therefore, SVM was better than ANN for survival prediction.

• Journal of Environmental Health Sciences
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• v.7 no.2
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• pp.119-126
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• 1981

This study aims to research on the actual state of the ways that the aged people live in Seoul use intentionally or unintentionally to maintain in their health. The aged people selected randomly for the study are 541 men and 902 women who are all more than 65 years old. This survey carried out from April to May in 1980. The results of this study are summed up as follows: 1. The main means of making a living engage was agriculture with the per cent of 57. 3 and next was commerce (11.9%). 2. As for their staple foods, the majority of them eat mixed food of rice and barley, and the rest eat rice or minor-grain mixed rice. As subsidiary foods, vegetables are the most common side dishes (68.9%) and see-weeds (6.7%) are taken by the minority of them. 3. Most of them (74.6%) frequently or occasionally take special health foods to maintaing their health. The most common health food turned out to be tonic liquor to men, while honey to women. 4. The majority of them(23.2% of men and 45.5% women) refrain from drinking and smoking. 5. 39.5 per cent of men and 25.5 per cent of wome) take light exercise such as going up hill and walking. 6. The majority of them undergo routine health check with the per cent of 10.8 or occasioanal health check with the 42.9. As medical treatment, many of them(45.9%) take Chinese remedies, western remedies(39.1%) and folk remedies (15.0%). 7. Many of them (66.0%) feel subjective symptoms about some geriatric diseases such as neuralgia, hypertension and cough. 8. Many of them (63.2%) free from mental trouble, while 17.7 per cent of them appeal to no job to do, 10.0 per cent of alienation and 9.1 per cent of domestic troubles. 9. Their subjective judgements of their secrets of health and longevity attach more importance to leading a regular life. 10. Most of them want to be served appropriate medical care, rest place, health consultations, etc. All these results reveal that health and longevity of the aged people are maintained by necessary cares and efforts, not by accident nor by apathy. It is thus highly desired tha tmany studies, enlightments and nationwide support about this problem be carried out in future.