• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.3
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• pp.35-40
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• 2021

In order to investigate the degree of solubilization of sewage sludge using sono-activated persulfate(UV/PP), VSS reduction rate, solubilization rate and extracellular polymeric substances were measured. Ultrasonic(US) and alkali·ultrasonic method using sodium hydroxide(US/SH) were compared. Under the persulfate·ultrasonic conditions, the VSS reduction rate and the solubilization rate increased to 27.6% and 58.9%, respectively. TB-EPS as Carbohydrate and Protein were extracted by 770 mg/L and 2,162 mg/L. Compared to the other methods, US and US/SH, the VSS reduction rate and solubilization rate were higher. And also, according to the TB-EPS values, cell wall destruction was more efficient.

• Progress in Medical Physics
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• v.28 no.4
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• pp.226-231
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• 2017

The aim is to investigate the spectra responsibilities of QD (Quantum Dot) for the innovation of new dosimetry application for therapeutic Megavoltage X-ray range. The unique electrical and optical properties of QD are expected to make it a good sensing material for dosimeter. This study shows the spectra responsibility of toluene based ZnCd QD and PPO (2.5-diphenyloxazol) mixed liquid scintillator. The QDs of 4 sizes corresponding to an emission wavelength (ZnCdSe/ZnS:$440{\pm}5nm$, ZnCdSeS:470, 500, $570{\pm}5nm$) were utilized. A liquid scintillator for control sample was made of toluene, PPO. The Composition of QD loaded scintillators are about 99 wt% Toluene as solvent, 1 wt% of PPO as primary scintillator and 0.05, 0.1, 0.2 and 0.4 wt% of QDs as solute. For the spectra responsibility of QD scintillation, they were irradiated for 30 second with 6 MV beam from a LINAC ($Infinity^{TM}$, Elekta). With the guidance of 1.0 mm core diameter optical fiber, scintillation spectrums were measured by a compact CCD spectrometer which could measure 200~1,000 nm wavelength range (CCS200, Thorlabs). We measured the spectra responsibilities of QD loaded organic liquid scintillators in two scintillation mechanisms. First was the direct transfer and second was using wave shifter. The emission peaks from the direct transfer were measured to be much smaller luminescent intensity than based on the wavelength shift from the PPO to QDs. The emission peak was shifted from PPO emission wavelength 380 nm to each emission wavelength of loaded QD. In both mechanisms, 500 nm QD loaded samples were observed to radiate in the highest luminescence intensity. We observed the spectra responsibility of QD doped toluene based liquid scintillator in order to innovate QD dosimetry applicator. The liquid scintillator loading 0.2 wt% of 500 nm emission wavelength QD has most superior responsibility at 6 MV photon beam. In this study we observed the spectra responsibilities for therapeutic X-ray range. It would be the first step of innovating new radiation dosimetric methods for radiation treatment.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.377-384
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• 2005

Algae causes not only the eutrophication of lake, but also the deterioration of drinking water process. Especially, algogenic organic matters(AOM) are assumed as disinfection by-products(DBPs) precursors like humic and fulvic acids. In this study, it was investigated the characteristics changes of algogenic organic matter(AOM) by prechlorination and coagulation treatment. Evaluation of enhanced coagulation and applicability of UV oxidation process were also evaluated as the drinking water treatment system for the eutrophicated water source. prechlorination was effective process for algae removal but caused releasing of dissolved organic matter(DOC) into water due to the destruction of algae's cell. In coagulation treatment with Fe(III) coagulant, reaction pH is an important factor for the removal of AOM and triholomathanes(THMs). At pH 5, removal efficiency of DOC and THMs were dramatically improved by 50% and 28%, respectively, in comparison with the conventional coagulation treatment at about pH 7. Photo-Fenton($UV/H_2O_2/Fe^{3+}$) process among the UV oxidations is the most effective system to remove AOM, but its removal efficiency was lower than that of enhanced coagulation treatment at pH 5.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.737-747
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• 2017

This experiment was carried out to determine the optimal concentration of agricultural organic materials using sulfur and oil for the insect pest control in pepper and cherry tomato cultivation. The control value of aphids and Oriental tobacco budworm (OTB) was examined one day after spraying with sulfur preparation (SP) (0.33~0.17%), oil preparations (OP) (2.00~0.33%), SP+OP, OP+ginkgo leaf extracts (GLE), SP+OP+GLE on the "Super Manidaa"pepper. The aphid control in pepper was complete by applications of SP+OP (0.25+1.00%) in the early growth stage and the control value was above 98.1% by the application of OP+GLE (1.00+1.00 %), SP+OP+GLE (0.25+1.0+1%), SP+OP+GLE (0.25+1.0+0.5%) in the middle to late growth stage while showing 0% in the control treatment. The OTB was completely controlled by the 3 times application with the high concentration of SP+OP (0.25+1.00%) in pepper cultivation. This result indicates that the oil and the sulfur preparations should be applied at low concentration before insect pests do not appeared, and then sprayed at the high concentration after they appear at pepper plant. The greenhouse whitefly in 'Minichal' tomatoes was completely controlled by three times application of SP (0.25~0.33), OP (1.0~2.00%). and all the treatment of SP+OP. However, continuous control with intervals of 1~3 days was considered favorable in the tomato plant. By the periodical control with agricultural organic materials using sulfur and oil, the greenhouse whitefly, which is a high-temperature insect pest, several moths of OTB did not occur at all. In conclusion, SP+OP (0.17%+0.33%) treatment was the most economical combination to control the aphid, OTB, and greenhouse whitefly in pepper and tomato cultivation when considering operating cost. In addition, we recommend that SP should not be sprayed on the plant shoots during the day time from July to August because of high temperature.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.3
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• pp.189-199
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• 2015

In this study, we have investigated the stability of sunscreens based on the solubility of organic UV absorbers in the oil and sun protection efficacy of the products composed of a combination of organic UV absorbers to develop more stable and efficient sunscreen products. Results showed that the solubility of the organic UV absorber and stability were varied depending on the type, storage conditions and concentration of oil. It was also observed from the products in the emulsion type. Various UV absorbances were determined to the products composed of the combination of organic UV absorbers. In some combinations, a synergistic effect was observed to make an increase in absorbance compared to a single component. In other cases, specific synergistic effect was displayed only when combined with the particular component. In addition, the storage condition also affected the sunscreen efficacy. In conclusion, this study confirmed that there are various factors which could affect the UV-blocking efficiency of sunscreen products.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.400.1-400.1
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• 2016

Interfacial engineering approaches as an efficient strategy for improving the power conversion efficiencies (PCEs) of inverted polymer solar cells (iPSCs) has attracted considerable attention. Recently, polymer surface modifiers, such as poly(ethyleneimine) (PEI) and polyethylenimine ethoxylated (PEIE), were introduced to produce low WF electrodes and were reported to have good electron selectivity for inverted polymer solar cells (iPSCs) without an n-type metal oxide layer. To obtain more efficient solar cells, quantum dots (QDs) are used as effective sensitizers across a broad spectral range from visible to near IR. Additionally, they have the ability to efficiently generate multiple excitons from a single photon via a process called carrier multiplication (CM) or multiple exciton generation (MEG). However, in general, it is very difficult to prepare a bilayer structure with an organic layer and a QD interlayer through a solution process, because most solvents can dissolve and destroy the organic layer and QD interlayer. To present a more effective strategy for surpassing the limitations of traditional methods, we studied and fabricated the highly efficient iPSCs with mono-layered QDs as an effective multi-functional layer, to enhance the quantum yield caused by various effects of QDs monolayer. The mono-layered QDs play the multi-functional role as surface modifier, sub-photosensitizer and electron transport layer. Using this effective approach, we achieve the highest conversion efficiency of ~10.3% resulting from improved interfacial properties and efficient charge transfer, which is verified by various analysis tools.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.1
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• pp.123-133
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• 2007

The presence of antibiotics in the wastewater from livestock farm due to its over-application should be concerned because they could change microbial ecology, increase the proliferation of antibiotic resistant pathogens, provoke toxic effect on aquatic species. In addition, these antibiotics can cause negative effect on the performance of biological wastewater treatment due to its antibacterial properties. In this study, our aim is to evaluate the effect of some common used antibiotic in Korea piggery farm such as oxytetracycline (OTC) to nitrification efficiency as well as organic compounds removal rate in biological system for treating piggery wastwater. The experiment was conducted in aeration batch reactor and lab-scale $A_2/O$(Anoxic-Anoxic-Oxic) system. From this study, it would be suggested that the piggery wastewater characterization should be examined in order to assess the fraction of common used antibiotics. The alternative treatment processes for piggery wastewater having high-strength antibiotics might be suggested in the future work.

• Korean Journal of Organic Agriculture
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• v.8 no.1
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• pp.101-109
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• 1999

In order to investigate the possibility of treating the different mixture ratios of apple pomace and nightsoil sludge by vermicomposting was performed and the stability of worm casts, and availability of worm casts as plant growth media was evaluated by the analysis of chemical composition. The results were obtained as follows ; 1. The value of cast production at 100% apple pomace treatment was higher than those of other mixture ratios of apple pomace and nightsoil sludge. 2. The highest values of increasing rate and reproductive efficiency were obtained at mixture ratios of 60% apple pomace with 40% nightsoil sludge. 3. The value of increasing rate at 100% nightsoil sludge treatment was lower that those of other mixture ratios of apple pomace and nightsoil sludge. 4. Organic matter, available inorganic nutrients and stability of worm casts showed high values in all treatments. It means that worm casts are an excellent plant growth media source with a high chemical composition and their stability.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1141-1145
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• 2005

A contactor coupled sequencing batch reactor composed of pre-anoxic contact zone and intermittently aerated zone was proposed and operated for nitrogen removal. Emphasis was placed on the fact that the contactor can be operated in a rapid reaction mode that results In biological uptake but incomplete metabolism of organic matter. Consequently, 61.2% of the sewage SCOD was adsorbed to activated sludge by 30-minute contact reaction. The specific uptake of organic matter was 22.3 mg SCOD/g MLVSS that enhanced the denitrification efficiency in the following denitrification stage. The removal efficiencies of the organic matter(SCOD) and the total nitrogen(T-N) were 86% and about 60% at the TCOD/TKN ratio as low as 6.0, respectively.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1363-1374
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• 2010

This study examined the physical and chemical properties of soil in Jang-San wetland in Busan Metropolitan City. The wetland covers wide and flat area comparing to its outside. The samples of the wetland soil were collected and analyzed in order to identify the profiles and chemical properties. According to the analyses of soil moisture and particle size distribution, the wetland soil mostly belongs to sandy loam with the soil moistures of 14.9-153.2%. The soil profiles are configured with O, A, B, and C horizons from the land surface. The organic matter content (2.38-16.7%) at most sampling locations decreases downwardly with the highest at 0-20 cm depth. The organic matter content has a good positive relationship with soil moisture content. According to X-ray diffraction analysis, the wetland soils contain quartz and feldspar (the main components of rhyolite porphyry) as well as montmorillonite, gibbsite, and kaolinite (the weathered products of feldspar). The wetland soil displays the highest iron concentration (average 22,052 mg/kg), indicating oxidation of iron. High concentrations of potassium (average 17,822 mg/kg) and sodium (average 5,394 mg/kg) originate from the weathering of feldspar. Among anions, sulfate concentration is highest with average 9.21 mg/kg that may originate from sulfate minerals and atmosphere.