• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.575-585
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• 2000

Mass and elemental dry deposition fluxes and ambient particle size distributions were measured using dry deposition plates, a cascade impactor. and a CPS(Coarse Particle Sampler), from July to November 1998 in Seoul. Korea. Primarily anthropogenic elemental fluxes (Cu, Mn, Ni, Pb, Zn) were on average one to two orders of magnitude lower than primarily crustal elements (Al, Ca). Complete total and elemental particle size distributions showed trimodal size distributions due to the peak in particles larger than $10{\mu}m$ in diameter. A multi-step model and the Sehmel-Hodgson model were used to calculate total and cumulative deposition fluxes. The result indicated that dry deposition fluxes were extremely sensitive to the mass of particles larger than $10{\mu}m$ in diameter due to their high dry deposition velocities. The result showed that particles larger than $10{\mu}m$ in diameter dominated atmospheric dry deposition. The modeled fluxes calculated using the measured atmospheric particle size distributions and modeled deposition velocities were compared to measured ones. In general, the measured mass and elemental fluxes agreed well with the modeled ones.

• Korean Journal of Materials Research
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• v.20 no.7
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• pp.356-363
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• 2010

For this paper, we investigated the area specific resistance (ASR) of commercially available ferritic stainless steels with different chemical compositions for use as solid oxide fuel cells (SOFC) interconnect. After 430h of oxidation, the STS446M alloy demonstrated excellent oxidation resistance and low ASR, of approximately 40 $m{\Omega}cm^2$, of the thermally grown oxide scale, compared to those of other stainless steels. The reason for the low ASR is that the contact resistance between the Pt paste and the oxide scale is reduced due to the plate-like shape of the $Cr_2O_3$(s). However, the acceptable ASR level is considered to be below 100 $m{\Omega}cm^2$ after 40,000 h of use. To further improve the electrical conductivity of the thermally grown oxide on stainless steels, the Co layer was deposited on the stainless steel by means of an electroless deposition method; it was then thermally oxidized to obtain the $Co_3O_4$ layer, which is a highly conductive layer. With the increase of the Co coating thickness, the ASR value decreased. For Co deposited STS444 with 2 ${\mu}m$hickness, the measured ASR at $800^{\circ}$ after 300 h oxidation is around 10 $m{\Omega}cm^2$, which is lower than that of the STS446M, which alloy has a lower ASR value than that of the non-coated STS. The reason for this improved high temperature conductivity seems to be that the Mn is efficiently diffused into the coating layer, which diffusion formed the highly conductive (Mn,Co)$_3O_4$ spinel phases and the thickness of the $Cr_2O_3$(S), which is the rate controlling layer of the electrical conductivity in the SOFC environment and is very thin

• Macromolecular Research
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• v.17 no.12
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• pp.963-968
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• 2009

Liquid crystal (LC; E7 and/or ML-0249)-embedded, poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based, polymer electrolytes were prepared for use in dye-sensitized solar cells (DSSCs). The electrolytes contained 1-methyl-3-propylimidazolium iodide (PMII), tetrabutylammonium iodide (TBAI), and iodine ($I_2$), which participate in the $I_3^-/I^-$ redox couple. The incorporation of photochemically stable PVdF-co-HFP in the DSSCs created a stable polymer electrolyte that resisted leakage and volatilization. DSSCs, with liquid crystal(LC)-embedded PVdF-co-HFP-based polymer electrolytes between the amphiphilic ruthenium dye N719 absorbed to the nanocrystalline $TiO_2$ photoanode and the Pt counter electrode, were fabricated. These DSSCs displayed enhanced redox couple reduction and reduced charge recombination in comparison to that fabricated from the conventional PVdF-co-HFP-based polymer electrolyte. The behavior of the polymer electrolyte was improved by the addition of optimized amounts of plasticizers, such as ethylene carbonate (EC) and propylene carbonate (PC). The significantly increased short-circuit current density ($J_{sc}$, $14.60\;mA/cm^2$) and open-circuit voltage ($V_{oc}$, 0.68 V) of these DSSCs led to a high power conversion efficiency (PCE) of 6.42% and a fill factor of 0.65 under a standard light intensity of $100\;mW/cm^2$ irradiation of AM 1.5 sunlight. A DSSC fabricated by using E7-embedded PVdF-co-HFP-based polymer electrolyte exhibited a maximum incident photon-to-current conversion efficiency (IPCE) of 50%.

• Journal of the Korean Electrochemical Society
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• v.19 no.3
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• pp.95-100
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• 2016

A method for electrochemical degradation of the perchlorate anion ($ClO_4{^-}$) using mercury film electrode has been studied. Electrochemical method has relatively simple pre-treatment. However, electrochemical method should avoid interference from hydrogen evolution at the applied potential to degradation of perchlorate ion, and thus applied electrode should have large hydrogen overvoltage which suppressed the hydrogen evolution at the working reduction potential to prevent hydrogen evolution. In this study, we used mercury film electrode as a working electrode which has a large overvoltage. Ag / AgCl (sat. NaCl) was used as a reference electrode, and platinum was used as a counter electrode. Mercury film electrode was made by cyclic voltammetry (CV) method. The deposition time was decided as 10 minute, and the stability of the mercury electrode in perchlorate solution was confirmed by CV. The reduction potential of perchlorate was checked by using CV method, and decomposition of perchlorate was performed by using chronoamperometric (CA) method. Also, ion chromatography (IC) was used to confirm the degradation rates of perchlorate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.671-675
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• 2002

The present study was conducted to elucidate functional properties of sulfated polysaccharides from ascidian tunics, In physical properties of the crude polysaccharides, emulsion ability and foaminess were more excellent compared with chitin and chitosan, particular dye binding capacity was prominent. Anti-blood coagulation of partially purified sulfnted polysaccharides showed with respect to APTT (Activated partial thromboplastin time). Especially, active fraction $(F_4)$ obtained by DEAE-cellulose ion exchange chromatography showed highest activity, which was approximately $20\%$ of the activity of heparin. ACE inhibitory activity also similar to anticoagulant activity. Active fraction $(F_4)$ obtained by DEAE-cellulose ion exchange chromatography showed about $34\%$, in ACE inhibitory activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.965-970
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• 2003

This study has been performed to develope a method for the simultaneous determination of 1,4-dioxane (DOX), epichlorohydrin (EPC), propylene chlorohydrin (PCH), ethylene chlorohydrin (ECH) and 1,3-dichloro-2-pro-panol (DCP) in polysorbates, chloline chloride, choline bitartrate, modified starch and spices by purge and trapgas chromatography. Experimental design was used to select a suitable trap by measuring the limit of detection (LOD) and to investigate the effect of temperature and salt of extraction, and the percentage of recovery in various matrix. The LOD of DOX, EPC, PCH, ECH and DCP were 1.38$\mu\textrm{g}$, 0.23$\mu\textrm{g}$, 3.30$\mu\textrm{g}$, 3.97$\mu\textrm{g}$, 20.43$\mu\textrm{g}$ respectively, by means of using Vorcarb 3000 trap with 5$0^{\circ}C$ sample sparger. Excluding EPC, the recoveries of target compounds were above 90% in all matrix. Target compounds in polysorbates (17), choline chloride (5), choline bitartrate (5), modified starch (8) and spices (25) were not detected. But 2.5 ppm of DOX was detected in Tween 80.

• Korean Journal of Pharmacognosy
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• v.48 no.4
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• pp.329-338
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• 2017

This study was investigated the changes of quality stability and physicochemical characteristics of the Korean red ginsengs stored for a long times over 20 years. The Korean red ginsengs were stored for 4 to 22 years in canned packaging with polypropylene film and wooden box at room temperatures. The unusal phenomena such as discoloration and pin hole in packaging were not observed. General bacteria showed the vlaues of below 100 CFU/g, coliform groups and molds were not found in any samples stored for 22 year. Any samples also were not detected in mycotoxins. The contents of moisture, ash and crude saponin were the levels of 10.6~11.1%, 3.8~4.2% and 4.1~4.7% during the whole storage periods, respectively. The contents of maltol, which has been known as characteristic flavour and antioxidant of Korean red ginseng, showed remarkably increasing tendency from 0.10 mg/g for 4 years to 2.53 mg/g for 22 years during the storage. The contents of AFG (arginyl-fructosyl-glucose), arginine and free sugar were slightly decreased. Acidic polysaccharide and ginsenoside were not changed significantly during the storage periods. The contents of acidic polysaccharide and total ginsenosides were the 75.1~76.3 mg/g and 15.1~16.6 mg/g, respectively. The sums of ginsenoside-Rg1,-Rb1 and -Rg3s were the ranges of 9.3~9.9 mg/g and PD (ginsenoside-Rb1, -Rb2,-Rc,-Rd,-Rg3s,-Rg3r)/PT (ginsenoside-Rg1,-Rg2,-Re,-Rf,-Rh1) saponin ratios were the levels of 1.4~1.5. These results suggest that Korean red ginsengs stored for long periods show relatively stable quaility stabilities and not significantly changed the contents of ginsenoside and polysaccharide during the storage up to 22 years.

• Journal of Chest Surgery
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• v.13 no.1
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• pp.13-20
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• 1980

Heparin would have been used for preventing clotting of blood during extracorporeal circulation and subsequent use of protamine sulfate and made possible the neutralization of heparin. This procedure has been adopted for eliminating one of the great causes of bleeding, especially in cardiac surgery. In this experiment, the hypocoagulability of blood induced by heparin followed by neutralization with treatment of protamine sulfate were estimated by the Lee-White clotting time [CT], partial thromboplastin time [PTT] and protamine titration test. The results were as follows: 1] Comparison of clotting time between the heparinized [2.0 mg/kg] and non-heparinized dogs was done using CT and PT`I` of the blood. In heparinized group [Group I], the CT lasted infinitively and prolongation of PTT [4 times than normal] until 60 minutes. The CT [2 times] and PTT [3 times] has been shortened after 90 minutes, however they returned to normal limit level within 180 minutes. 2] The determination of appropriate ratio of heparin and protamine In vivo were performed. The group II [heparin 2.0 mg/kg, protamine 1.0 mg/kg] revealed rapid decrease of CT and PTT, but returned to normal after 120 minutes. The group III [heparin 2.0 mg/kg, protamine 2.0 mg/kg] returned rapidly to normal within 15 minutes. The group IV [heparin 2.0 mg/kg, protamine 3.0 mg/kg] recovered its normal level after 60 minutes. The group V [heparin 2.0 mg/kg, protamine 4.0 mg/kg] recovered its normal level after 90 minutes. 3] In the combined experimental study In vivo and vitro, the protamine titration test was done using the dog which were given 2.0 mg/kg and 3.0 mg/kg of heparin, respectively and coagulation time were checked after 15, 30, 60 and 120 minutes. The complete neutralization was showed to be heparin-protamine ratio of 1:1 to 1.5. 4] In vitro study, fresh blood was drawn into known amount of heparin content [20, 40, 60 and 100/ug per 1 ml of blood] syringe, thereafter protamine titration test was done. In all cases, the complete neutralization was found in heparin-protamine ratio of 1:0.85 to 1.5. 5] It was found by the present experiment that the ideal heparin-protamine ratio was 1:1 within 60 minutes and 1:0.5 after 60 minutes for avoiding the serious side effect due to overadministration of protamine sulfate.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.149-158
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• 2005

This paper describes design, fabrication, and application of the silicon based temperature controllable micro reactor. In order to achieve fast temperature variation and low energy consumption, reaction chamber of the micro reactor was thermally isolated by etching the highly conductive silicon around the reaction chamber. Compared with the model not having thermally isolated structure, the thermally isolated micro reactor showed enhanced thermal performances such as fast temperature variation and low energy consumption. The performance enhancements of the micro reactor due to etched holes were verified by thermal experiment and numerical analysis. Regarding to 42 percents reduction of the thermal mass achieved by the etched holes, approximately 4 times faster thermal variation and 5 times smaller energy consumption were acquired. The total size of the fabricated micro reactor was $37{\times}30{\times}1mm^{3}$. Microchannel and reaction chamber were formed on the silicon substrate. The openings of channel and chamber were covered by the glass substrate. The Pt electrodes for heater and sensor are fabricated on the backside of silicon substrate below the reaction chamber. The dimension of channel cross section was $200{\times}100{\mu}m^{2}$. The volume of reaction chamber was $4{\mu}l$. The temperature of the micro reactor was controlled and measured simultaneously with NI DAQ PCI-MIO-16E-l board and LabVIEW program. Finally, the fabricated micro reactor and the temperature control system were applied to the thermal denaturation and the trypsin digestion of protein. BSA(bovine serum albumin) was chosen for the test sample. It was successfully shown that BSA was successfully denatured at $75^{\circ}C$ for 1 min and digested by trypsin at $37^{\circ}C$ for 10 min.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.21-29
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• 1998

The rare-earth orthoborate family, RM3(BO3)4 is known to be the most promising material for the microlaser host. To grow LaSc3(BO3)4 single crystal, the phase relation of the system LaBO3-ScBO3 was investigated by DTA method. LaSc(BO3)4 was the unique intermediate compound in the binary system the peritectic reaction point of which was 1495 ±2℃. Owing to the peritectic behavior of the compound, the crystal growth of the rare-earth Sc-borate was carried out by pulling from the melt-soultion of La1+xSc3-x(BO3)4. The optimal conditions for the growth of LaSc3(BO3)4 were determined by traditional CZ method : pulling speed 0.7mm/hr, rotation speed 7-10 rpm under reduction condition. Pt and Ir crucibles could be used for about 8-10 times of growth. The effect of thermal configurations on the temperature distribution was investigated. A special two-coordinate manipulator was made for the precise movement of thermocouples from the melt to the top of the furnace for several thermal configurations. The radial gradient on the melt surface depends strongly on the construction of the afterheater. On the other hand, the axial gradient was mainly propotional to both the opening degree of baffle plate and the mutual positions of crucible and heater.