• Resources Recycling
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• v.15 no.1 s.69
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• pp.37-45
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• 2006

For treating a huge amount of plastic waste with the environment problem, pyrolysis of plastic waste into alternative fuel oil is one or important issue in recycling methods. This study was introduced over the trend or generation of plastic waste, in Korea pyrolysis technology in domestic and foreign countries, basic technology in pyrolysis process and new technology of pyrolysis developed in KIER (Korea Institute of Energy research). The characteristics of process developed in KIER are the continuous loading treatment or mixed plastic waste with an automatic control system, the minimization of wax production by circulation pyrolysis system in non-catalytic reactor, the reuse of gas produced and the oil recovery from sludge generated in pyrolysis plant, which have greatly the advantage economically and environmetally. The experiment result data in 300 ton/yr pilot plant showed about $81\;wt\%$ liquid yield for 3 days continuous reaction time, and also the boiling point distribution of light oil (LO) and heavy oil (HO) produced in distillation tower was a little higher than that of commercial gasoline and diesel, respectively.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.296-313
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• 2014

A QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) multiresidue method was developed for the simultaneous analysis of 124 pesticides in soil by LC-MS. The procedure involved liquid extraction of soil immersed with 0.2N $NH_4Cl$ by acetonitrile with 1% acetic acid, followed by anhydrous $MgSO_4$ and sodium acetate, and dispersive SPE cleanup with $MgSO_4$, primary secondary amine (PSA) and $C_{18}$. The extracts were analyzed with LC-MS/MS in ESI positive mode. Standard calibration curves were made by matrix matched standards and their correlation coefficients were higher than 0.99. Recovery studies for the validation were carried out using two type soils, loam and sandy loam, at four concentration levels (0.005, 0.01, 0.02, and 0.1 mg/kg). The recoveries of pesticides were in the range of 70-120% with < 20% RSD except 4 pesticides, Benfuracarb, Ethiofencarb, Pymetrozine, and Pyrethrin. This result indicated that the method using QuEChERS and LC-MS/MS could be applied for the simultaneous determination of pesticide residues in soils.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.193-198
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• 2017

Scutellaria baicalensis, Eleutherococcus senticosus, and Angelica sinensis have been used as raw materials for health functional foods. This study was conducted to develop a novel method to analyze levels of baicalin (Scutellaria baicalensis), eleutheroside E (Eleutherococcus senticosus), and ligustilide (Angelica sinensis) simultaneously in health functional foods. The methanol extracted samples were analyzed and quantified via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive ion mode and the negative ion mode using multiple reaction monitoring. Standard calibration curves confirmed linearity with the correlation coefficient ($r^2$) of > 0.99 at $100-2000{\mu}g/mL$ concentration range. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of $13.0{\sim}35.2{\mu}g/L$ and $39.3{\sim}106.7{\mu}g/L$, respectively. The recovery results ranged between 91.4~109.9% at 3 different concentration levels with relative standard deviations (RSDs) less than 5%. The proposed analytical method was characterized with high accuracy and acceptable precision. The new method would be an effective tool to analyze baicalin, eleutheroside E, and ligustilide simultaneously in raw materials of health functional foods.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.556-560
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• 2015

This study was aimed at investigating the natural occurrence of caffeine, theobromine, and theophylline in tea leaves. Sample clean-up was based on a simple solid phase extraction (SPE) treatment, and simultaneous analysis was performed by high performance liquid chromatography (HPLC). This method showed good results in terms of linearity, recovery, precision, limit of detection (LOD), and limit of quantitation (LOQ). The caffeine, theobromine, and theophylline contents of tea leaves (n = 228) ranged from 5.4 to 58.2 mg/g, from not detected to 11.2 mg/g, and from not detected to 0.7 mg/g, respectively. The results obtained in this study can be used as fundamental data of caffeine, theobromine, and theophylline contents in tea leaves.

• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.155-160
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• 1987

This study was carried out to determine the effects of cryoprotectants, freezing and thawing rates on the survival of 8-cell mouse embryos. The female ICR mice were induced to superovulated by intraperitoneal injections of 5 i.u. PMSG and 5 i.u. HCG given 48h apart and then were paired with males of the same strain. They were killed and embryos were flushed from the oviducts and uteri on 3 days after injection of HCG. Embryos were flushed with modified Dulbecco's phosphate buffered saline and equilibrated with 1.5M-dimethyl sulfoxide (DMSO) or 1.5M-glycerol by 3-step procedure. The freezing rates of the embryos were 1$^{\circ}C$/min from room temperature to -5$^{\circ}C$ and the embryos were seeded at -5$^{\circ}C$. After being held for 3 min at the seeding temperature, the rates were 0.3$^{\circ}C$/min from -5$^{\circ}C$ to -35$^{\circ}C$. From -35$^{\circ}C$ to -7$0^{\circ}C$, the rates were divided into 0.1$^{\circ}C$/min, 1$^{\circ}C$/min and 1$0^{\circ}C$/min, respectively. After being held for 5 min at -7$0^{\circ}C$, the embryos were plunged directly into liquid nitrogen. The embryos were thawed at 4$^{\circ}C$/min and 12$^{\circ}C$/min from -196$^{\circ}C$ to 37$^{\circ}C$, and for 2 min in 37$^{\circ}C$ water bath, respectively. The average number of ovulation points and embryos recovered were 42.7 and 34 appearing 79.5% recovery rate. Eight cell embryos in the embryos recovered were 26.3. The survival rates of embryos according to the freezing rates in the presence of 1.5M-DMSO were 73.5~80.6% at 0.1$^{\circ}C$/min, 75.0~79.5% at 1$^{\circ}C$/min and 52.8~54.7% at 1$0^{\circ}C$/min, but in the presence of 1.5M-glycerol were 62.9~67.6% at 0.1$^{\circ}C$/min, 61.4~68.3% at 1$^{\circ}C$/min and 25.5~30.2% at 1$0^{\circ}C$/min. The survival rates of embryos were not affected by the thawing rates.

• Analytical Science and Technology
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• v.26 no.1
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• pp.99-105
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• 2013

To identify oxidative hair dyes in hair-coloring products, the thin-layer chromatography (TLC) screening method was used in accordance with Korean Quasi-drug Codex. However, the TLC method is not reliable when there are very small amount of materials to be tested or when $R_f$ values of several components are similar. In this study, Ultra Performance Liquid Chromatography (UPLC) with a rapid sample preparation method was developed for the reliable and sensitive identification of active components contained in oxidative hair-coloring products. Hexane-distilled water was used for the extraction of active components contained in the products prior to UPLC analysis. The limit of detection of active components was 6.7-77.9 ${\mu}g/L$, and the limit of quantitation was 22.3-259.7 ${\mu}g/L$. Except for ${\alpha}$-naphthol, the range of recovery ratio was 96.2-101.5%. From this study, we demonstrated that oxidative active hair-coloring components can easily be analyzed by rapid extraction method followed by UPLC analysis.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.193-200
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• 2005

[ $^{14}C$ ] and $^{3}H$ in the evaporator bottom (EB) discharged from the Nuclear power plant (NPP) were extracted simultaneously into a gaseous $^{14}CO_{2}$ and liquefied HTO by using the chemical oxidation, which is the method to oxidize samples completely using potassium persulfate and sulfuric acid. The extracted $^{14}C$ and $^{3}H$ were counted by the liquid scintillation counter (LSC) after the quench correction. To examine the recovery of $^{14}C$ using the radioactive standards, $Na_{2}^{14}CO_{3}$, $^{14}C-alcohol$, and $^{14}C-toluene$ as $^{14}C$, and HTO as $^{3}H$ were used. Also, the most suitable method for oxidizing $^{14}C-toluene$, which is difficult to be oxidized, was investigated through FT-IR spectra according to the concentration of sulfuric acid. With the identical method, $^{14}C$ and $^{3}H$ in the EB generated in the NPP were assayed in the range of $8.35{\sim}l.38{\times}10^3$ Bq/g and $2.46{\times}10^2{\sim}1.40{\times}10^4$ Bq/g, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.690-698
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• 2010

Contamination of groundwater resources by organic chemicals has become an issue of increasing environmental concern. Surfactant-enhanced aquifer remediation (SEAR) is widely recognized as one of the most promising techniques to remediate organic contaminations in-situ. Solutions of surfactant or surfactant with polymer are used to dramatically expedite the process, which in turn, may reduce the treatment time of a site compared to use of water alone. In the design of surfactant-based technologies for remediation of organic contaminated aquifers, it is very important to have a considerable analysis using extensive numerical simulations prior to full-scale implementation. This study investigated the formation and flow of microemulsions during SEAR of organic-contaminated aquifer using the finite difference model UTCHEM, a three-dimensional, multicomponent, multiphase, compositional model. The remediation process variables considered in this study were the sequence of injection fluids, the injection and extraction rate, the concentrations of polymer in surfactant slug and chase water, and the duration of surfactant injection. For each variable, temporal changes in injection and production wells and spatial distributions of relative saturations in the organic phase were compared. Cleanup time and cumulative organic recovery were also quantified. The study would provide useful information to design strategies for the remediation of nonaqueous phase liquid-contaminated aquifers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.723-729
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• 2016

This study compared fin-tube and parallel-flow heat pipes for their sensible heat exchange rate, heat recovery amount, and air-side pressure drop. Tests were done with different refrigerant charging rates of 40-60% vol. and air flow rates of 300-1,400. The sensible heat exchange rate was highest for both types of heat pipes at a working fluid charge of 40% vol. and low flow rate. For the parallel-flow heat pipe, the 60% vol. charge is too high and results in a low sensible heat exchange rate. The reason is that the thicker liquid film of the tube wall deteriorates the heat transfer effect. Hence, the optimal charging rate is 40 to 50% vol. The evaporator heat pipe has a larger air-side pressure drop than the condenser section heat pipe. The reason is considered to be condensation water arising from the evaporator surface. Compared to the fin-tube heat pipe, the parallel-flow heat pipe showed better performance with a working fluid charging rate of 48%, volume of 41%, and an air-side pressure drop about 37%.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.34-46
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• 2005

For treating a huge amount of plastic waste with the environment problem, pyrolysis of plastic waste into alternative fuel oil is one of important issue in recycling methods. This study was introduced over the trend of generation of plastic waste, pyrolysis technology in domestic and foreign countries, basic technology in pyrolysis process and new technology of pyrolysis developed in KIER (Korea Institute of Energy Research). The characteristics of process developed in KIER are the continuous loading treatment of mixed plastic waste with an automatic control system, the minimization of wax production by circulation pyrolysis system in non-catalytic reactor, the reuse of gas produced and the oil recovery from sludge generated in pyrolysis plant, which have greatly the advantage economically and environmetally. The experiment result data in 300 ton/yr pilot plant showed about 81 wt% liquid yield for 3 days continuous reaction time, and also the boiling point distribution of light oil (LO) and heavy oil (HO) produced in distillation tower was a little higher than that of commercial gasoline and diesel, respectively.