• Food Engineering Progress
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• v.21 no.3
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• pp.225-232
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• 2017

Most of the red ginseng (RG) products contain active substances derived from hot water or alcohol extraction. Since active substances of RG are divided into two types - water-soluble and liposoluble - water or alcohol is needed as an extraction solvent and this leads the different extraction yields and components of the active substances. To overcome the limit, whole red ginseng powder can be used and consumed by consumers. In this study, the physicochemical properties and extractable active substance contents of variable-sized RG powder ($158.00{\mu}m$, $8.45{\mu}m$, and $6.33{\mu}m$) were analyzed, and dispersion stability was measured to investigate the suitable size of RG powder for industrial processing. In the results, no significant difference was found from the changes in color intensity and thiobarbutric acid tests at $4^{\circ}C$, $25^{\circ}C$, and $40^{\circ}C$ for 4 weeks. There was no significant difference on the production of antioxidants and ginsenoside among the samples (p>0.05). In dispersion stability, $RG-158.00{\mu}m$ was precipitated immediately, and the dispersion stabilities between $RG-8.45{\mu}m$ and $RG-6.33{\mu}m$ showed no significant difference. It implies that fine RG is suitable for the production process. With further study, it seemed that the physicochemical effects of RG particle sizes can be clearly revealed.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.217-223
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• 2010

This study was conducted to reclassify Dongsong series based on the second edition of Soil Taxonomy and to discuss the formation of Dongsong series distributed on the lava plain at Cheolweon in Korea. Morphological properties of typifying pedon of Dongsong series were investigated, and physico-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual. The typifying pedon of Dongsong series has brown (7.5YR 4/2) silty clay loam Ap horizon (0-16 cm), brown (7.5YR 4/2) silty clay loam BA horizon (16-22 cm), brown (7.5YR 4/2) silty clay Bt1 horizon (22-50 cm), reddish brown (5YR 5/4) silty clay Bt2 horizon (50-92 cm), and brown (7.5YR 4/3) silty clay loam Bt3 horizon (92-120 cm). It occurs on lava plain derived from baslt materials. The typifying pedon has higher bulk density than 0.90 Mg $m^{-3}$. That can not be classified as Andisol. But it has an argillic horizon from a depth of 22 to more than 120 cm, and a base saturation (sum of cations) of less than 35% at 125 cm below the upper boundary of the argillic horizon. It can be classified as Ultisol, not as Andisol or Alfisol. It has aquic conditions for some time in normal years in one or more horizons within 50 cm of the mineral soil surface, redoximorphic features between a depth of 25 cm, and a depth of 40 cm from the mineral soil surface, and redox concentrations, and 50%or more redox depletions with chroma of 2 or less in the matrix within the upper 12.5 cm of the argillic horizon. Therefore it can be classified as Aquult. It has episaturation, and keys out as Epiaquult. It has 50% or more chroma of 3 or more in one or more horizons between a depth of 25 cm from the mineral soil surface, and a depth of 75 cm. It can be classified as Aeric Aquult. Dongsong series have 35%or more clay at the particle-size control section, and have mesic soil temperature regime. Therefore they can be classified as fine, mesic family of Aeric Epiaquults, not as fine, mesic family of Typic Epiaqualfs. The Quarternary volcanic activities occurred in Jeju Island, Ulrung Island, Baekryeong Island, Cheolweon area, and Mt. Paekdu et al. in the Korean Penninsula. Most of them belong to the central eruption type, but Cheolweon area may be of the fissure eruption type. Dongsong series occur on Cheolweon lava plains derived from basaltic materials. Most soils distributed in Jeju Island, and derived from mainly pyroclastics are developed as Andisols. But Dongsong series distributed in Cheolweon lava plains which have a relatively dry climate and derived from basaltic materials are developed as Ultisols.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.3
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• pp.104-109
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• 1981

The experiment was designed to measure splash erosion and to investigate the relationships between soil detachment, kinetic energy and C factor at various soils and crops under the natural rainfall, using the modified Ellison cup. The results obtained were as follows: 1. Splash erosion increased as the texture was coarser, reaching a maximum amount in loamy sand of 12.6ton/10a/year, 9.7ton for loam, 9.0ton for sandy loam, and 7.0ton for clay loam. 2. Splash erosion positively related to kinetic energy ($EI_{30}$) but negatively to K value. 3. A considerable relationship between splash erosion and kinetic energy was observed under coverage less than 50%; however, it decreased with increasing canopy resulting in no relation over 90% coverage. The amount of soil detachment by natural rainfall ranged from 10 to 15ton/10a at various cropping systems. 4. The particle size distribution of splashed soil was similar to that of original one and fine sand($250-100{\mu}$) marked the highest detachment and splash.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.44-51
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• 2016

The powder core, conventionally fabricated from iron particles coated with insulator, showed large eddy current loss under high frequency, because of small specific resistance. To overcome the eddy current loss, the increase in the specific resistance of powder cores was needed. In this study, copper oxide coating onto electrically conductive iron particles was performed using a planetary ball mill to increase the specific resistance. Coating factors were optimized by the Response surface methodology. The independent variables were the CuO mass fraction, mill revolution number, coating time, ball size, ball mass and sample mass. The response variable was the specific resistance. The optimization of six factors by the fractional factorial design indicated that CuO mass fraction, mill revolution number, and coating time were the key factors. The levels of these three factors were selected by the three-factors full factorial design and steepest ascent method. The steepest ascent method was used to approach the optimum range for maximum specific resistance. The Box-Behnken design was finally used to analyze the response surfaces of the screened factors for further optimization. The results of the Box-Behnken design showed that the CuO mass fraction and mill revolution number were the main factors affecting the efficiency of coating process. As the CuO mass fraction increased, the specific resistance increased. In contrast, the specific resistance increased with decreasing mill revolution number. The process optimization results revealed a high agreement between the experimental and the predicted data ($Adj-R^2=0.944$). The optimized CuO mass fraction, mill revolution number, and coating time were 0.4, 200 rpm, and 15 min, respectively. The measured value of the specific resistance of the coated pellet under the optimized conditions of the maximum specific resistance was $530k{\Omega}{\cdot}cm$.

• The Journal of Korean Medicine
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• v.34 no.3
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• pp.54-68
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• 2013

Objectives: This study aimed to evaluate the effects of microparticles of Socheongryong-tang (SCRT) on chronic obstructive pulmonary disease (COPD) in a mouse model. Methods: The inhalable microparticles containing SCRT were produced by spray-drying with leucine as an excipient, and evaluated with respect to the aerodynamic properties of the powder by Andersen cascade impactor (ACI). Its equivalence to SCRT extract was evaluated using lipopolysaccharide (LPS) and a cigarette-smoking (CS)-induced murine COPD model. Results: SCRT microparticles provided desirable aerodynamic properties (fine particle fraction of $49.6{\pm}5.5%$ and mass median aerodynamic diameter of $4.8{\pm}0.3{\mu}m$). SCRT microparticles did not show mortality or clinical signs over 14 days. Also there were no significant differences in body weight, organ weights or serum chemical parameters between SCRT microparticle-treated and non-treated groups. After 14 days the platelet count significantly increased compared with the non-treated group, but the values were within the normal range. Inhalation of SCRT microparticles decreased the rate of neutrophils in blood, granulocytes in peripheral blood mononuclear cells (PBMC) and bronchoalveolar lavage fluid (BALF) and level of TNF-${\alpha}$ and IL-6 in BALF on COPD mouse model induced by LPS plus CS. This effect was verified by histological findings including immunofluorescence staining of elastin, collagen, and caspase 3 protein in lung tissue. Conclusions: These data demonstrate that SCRT microparticles are equivalent to SCRT extract in pharmaceutical properties for COPD. This study suggests that SCRT microparticles would be a potential agent of inhalation therapy for the treatment of COPD.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5601-5609
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• 2012

The fine particulate matter($PM_{10}$) concentrations and contents were measured to check the health and environment influential factors in Pohang Iron and Steel Industrial Complex and its vicinities. In addition, the $PM_{10}$ distribution for each year and season was surveyed using the regional air quality monitoring stations. The measuring on the $PM_{10}$ inside the industrial complex showed $61.3{\pm}12.1{\mu}g/m^3$ for average concentration of $PM_{10}$ which was measured by Dongil Industry and $44.3{\pm}8.1{\mu}g/m^3$ measured by steel manufacturing industry complex management office. Both of them satisfied the environmental air quality standard. The percentage of $SO_4{^2}$, $NO_3{^-}$, $NH_4{^+}$ which are the secondary ions created out of the $PM_{10}$ in Dongil Industry and steel manufacturing industry complex management office was checked and it was revealed that the percentage of ${SO_4}^{2-}$ was high and it is considered that the pollution source related with the sulfides exist at the industrial complex. They were in order of ${SO_4}^{2-}$ > $Cl^-$ > $NO_3{^-}$ > $F^-$ > $NH_4{^+}$ in Dongil Industry and ${SO_4}^{2-}$ > $Cl^-$ > $NO_3{^-}$ > $NH_4{^+}$ > $F^-$ in steel manufacturing industry complex management office.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.519-528
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• 2019

In 2017, Korea Institute of Geoscience and Mineral Resources (KIGAM) has excavated a trench at Yongjang-li in the city of Gyeongju to examine the evidence of fault movement related with the 2016 earthquake in unconsolidated sediments. In the trench profile, the author has observed the features of ongoing soil-forming processes and groundwater movement overlapped on the sedimentary layers. The soil formation was in its initial stage, and most of the original sedimentary layers could be observed. The color changes depending on the redox conditions and by the Mn/Fe oxide precipitation, however, were the most significant features obscuring sedimentary records. The dark Mn oxide precipitates formed at the groundwater levels often concealed the sedimentary unit boundaries. The groundwater levels varied depending on the particle sizes of the sedimentary layers contacting the groundwater, and the Mn oxide precipitates have formed at varying depths. The groundwater could move upward along the narrow pores in the fine-textured sedimentary layer more than a few meters showing the gray color indicating a reducing condition for iron.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.65-65
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• 2015

In this talk, I will introduce two topics. The first topic is the polymer light emitting diodes (PLEDs) using graphene oxide quantum dots as emissive center. More specifically, the energy transfer mechanism as well as the origin of white electroluminescence in the PLED were investigated. The second topic is the facile synthesis of eco-friendly III-V colloidal quantum dots and their application to light emitting diodes. Polymer (organic) light emitting diodes (PLEDs) using quantum dots (QDs) as emissive materials have received much attention as promising components for next-generation displays. Despite their outstanding properties, toxic and hazardous nature of QDs is a serious impediment to their use in future eco-friendly opto-electronic device applications. Owing to the desires to develop new types of nanomaterial without health and environmental effects but with strong opto-electrical properties similar to QDs, graphene quantum dots (GQDs) have attracted great interest as promising luminophores. However, the origin of electroluminescence (EL) from GQDs incorporated PLEDs is unclear. Herein, we synthesized graphene oxide quantum dots (GOQDs) using a modified hydrothermal deoxidization method and characterized the PLED performance using GOQDs blended poly(N-vinyl carbazole) (PVK) as emissive layer. Simple device structure was used to reveal the origin of EL by excluding the contribution of and contamination from other layers. The energy transfer and interaction between the PVK host and GOQDs guest were investigated using steady-state PL, time-correlated single photon counting (TCSPC) and density functional theory (DFT) calculations. Experiments revealed that white EL emission from the PLED originated from the hybridized GOQD-PVK complex emission with the contributions from the individual GOQDs and PVK emissions. (Sci Rep., 5, 11032, 2015). New III-V colloidal quantum dots (CQDs) were synthesized using the hot-injection method and the QD-light emitting diodes (QLEDs) using these CQDs as emissive layer were demonstrated for the first time. The band gaps of the III-V CQDs were varied by varying the metal fraction and by particle size control. The X-ray absorption fine structure (XAFS) results show that the crystal states of the III-V CQDs consist of multi-phase states; multi-peak photoluminescence (PL) resulted from these multi-phase states. Inverted structured QLED shows green EL emission and a maximum luminance of ~45 cd/m2. This result shows that III-V CQDs can be a good substitute for conventional cadmium-containing CQDs in various opto-electronic applications, e.g., eco-friendly displays. (Un-published results).

• Journal of the Korean Electrochemical Society
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• v.4 no.4
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• pp.172-175
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• 2001

Nanophase catalyst layer for direct methanol fuel cell has been fabricated by magnetron sputtering method. Catalyst metal targets and carbon were sputtered simultaneously on the Nafion membrane surface at abnormally higher gas (Ar/He mixture) pressure than that of normal thin film processing. They could be coated as a novel structure of catalyst layer containing porous PtRu or Pt and carbon particles both in nanometer range. Membrane electrode assembly made with this layer led to a reduction of the catalyst loading. At the catalyst loading of 1.5mg $PtRu/cm^2$ for anode and 1mg $Pt/cm^2$ for cathode, it could provide $45 mW/cm^2$ in the operation at 2 M methanol, 1 Bar Air at 80"C. It is more than $30\%$ increase of the power density performance at the same level of catalyst loading by conventional method. This was realized due to the ultra fine particle sizes and a large fraction of the atoms lie on the grain boundaries of nanophase catalyst layer and they played an important role of fast catalyst reaction kinetics and more efficient fuel path. Commercialization of direct methanol fuel cell for portable electronic devices is anticipated by the further development of such design.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.477-484
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• 2019

The purpose of this study is to present basic data for developing concrete with EMP shielding as the structure materials when constructing an EMP shielded building structure. In order to use metal-based recycled aggregates with excellent conductivity and easy procurement for EMP shielding concrete, an evaluation of the stability evaluation and EMP shielding performance was performed. Through the stability evaluation, it was found that the coarse aggregate stability criterion was satisfied, but the oxidized slag did not satisfy the fine aggregate stability criterion, the oxidized slag is not satisfied. In addition, as a result of fresh concrete, the workability is increased and the air volume is decreased. The compressive strength is increased due to the high density and coarse granularity of the recycled aggregates, which increased the cement paste and adhesion, thereby increasing the compressive strength. The results of an EMP shielding test show that aggregates with high shielding performance are electronic arc furnace(EAF) Oxidizing Slag and Cooper Slag. The shielding performance is expected to increase if the average particle size of aggregate is small or uniformly distributed.