• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.667-678
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• 2002

In this paper, a new radiating structure with a multi-layered two-dimensional metallic disk array was proposed for shaping the flat-topped element pattern. It is an infinite periodic planar array structure with metallic disks finitely stacked above the radiating circular waveguide apertures. The theoretical analysis was in detail performed using rigid full-wave analysis, and was based on modal representations for the fields in the partial regions of the array structure and for the currents on the metallic disks. The final system of linear algebraic equations was derived using the orthogonal property of vector wave functions, mode-matching method, boundary conditions and Galerkin's method, and also their unknown modal coefficients needed for calculation of the array characteristics were determined by Gauss elimination method. The application of the algorithm was demonstrated in an array design for shaping the flat-topped element patterns of $\pm$20$^{\circ}$ beam width in Ka-band. The optimal design parameters normalized by a wavelength for general applications are presented, which are obtained through optimization process on the basis of simulation and design experience. A Ka-band experimental breadboard with symmetric nineteen elements was fabricated to compare simulation results with experimental results. The metallic disks array structure stacked above the radiating circular waveguide apertures was realized using ion-beam deposition method on thin polymer films. It was shown that the calculated and measured element patterns of the breadboard were in very close agreement within the beam scanning range. The result analysis for side lobe and grating lobe was done, and also a blindness phenomenon was discussed, which may cause by multi-layered metallic disk structure at the broadside. Input VSWR of the breadboard was less than 1.14, and its gains measured at 29.0 GHz. 29.5 GHz and 30 GHz were 10.2 dB, 10.0 dB and 10.7 dB, respectively. The experimental and simulation results showed that the proposed multi-layered metallic disk array structure could shape the efficient flat-topped element pattern.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.218-223
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• 2016

The calculation method of ground heat exchange in greenhouses has different ideas in each design standard, so there is a big difference in each method according to the size of greenhouses, it is necessary to establish a more accurate method that can be applied to the domestic. In order to provide basic data for the formulation of the calculation method of greenhouse heating load, we measured the soil temperature distribution and the soil heat flux in three plastic greenhouses of different size and location during the heating period. And then the calculation methods of ground heat exchange in greenhouses were reviewed. The soil temperature distributions measured in the heating greenhouse were compared with the indoor air temperature, the results showed that soil temperatures were higher than room temperature in the central part of greenhouse, and soil temperatures were lower than room temperature in the side edge of greenhouse. Therefore, it is determined that the ground heat gain in the central part of greenhouse and the perimeter heat loss in the side edge of greenhouse are occurred, there is a difference depending on the size of greenhouse. Introducing the concept of heat loss through the perimeter of building and modified to reflect the size of greenhouse, the calculation method of ground heat exchange in greenhouses is considered appropriate. It was confirmed that the floor heat loss measured by using soil heat flux sensors increased linearly in proportion to the temperature difference between indoor and outdoor. We derived the reference temperature difference which change the direction of ground heat flow and the perimeter heat loss factor from the measured heat flux results. In the heating design of domestic greenhouses, reference temperature differences are proposed to apply $12.5{\sim}15^{\circ}C$ in small greenhouses and around $10^{\circ}C$ in large greenhouses. Perimeter heat loss factors are proposed to apply $2.5{\sim}5.0W{\cdot}m^{-1}{\cdot}K^{-1}$ in small greenhouses and $7.5{\sim}10W{\cdot}m^{-1}{\cdot}K^{-1}$ in large greenhouses as design standard data.

• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.55-64
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• 1989

Reduction and equilibrium of vanadium-DTPA (DTPA = diethylenetriaminepentaacetic acid, $H_5A$) complexes at mercury electrodes are studied in 0.5M $NaClO_4$ aqueous solution at 3.2 < pH < 10.5 and 25$^{\circ}$C. At 3.2 < pH < 5.9, the reduction reaction is $V{\cdot}A^{2-}+H^-+e^-=V{\cdot}HA^{2-}$, while at 5.9 < pH < 10.5 it is $V{\cdot}A^{2-}+H^-+e^-=V{\cdot}A^{3-}$. The stability constants of $V{\cdot}HA^{2-}$ and $V{\cdot}A^{3-}$ are found to be $6.46{\times}10^{9}$ and $3.09{\times}10^{14}$, respectively. V(IV)-DTPA undergoes stepwise complexation as $VO^{2+}+H_2A^{3-}=VO{\cdot}HA^{2+}H^{+}$ and $VO{\cdot}HA^{2-}=VO{\cdot}A^{3+}+H$, where acidity constant of $VO{\cdot}HA^{2-}$- is pKa = 7.15. Stability constants of $VO{\cdot}HA^{2-}$ and $VO{\cdot}A^{3-}$ are found to be $1.41{\times}10^{14}$ and $3.80{\times}10^{17}$, respectively. It is detected that $VO^{2+}-DATA$ is reduced irreversibly to $VO^{2-}$ with the transfer coefficient of $\alpha$ = 0.43. At more cathodic overpotential, the reduction is stepwise as V(IV)${\to}$V(III)${\to}$V(II). The first one corresponds to $VO{\cdot}HA^{2-}+e^{-}{\to}VO{\cdot}HA{3+}$ at 3.2 < pH < 7.2 and $VO{\cdot}A^{3-}+e^{-}{\to}VO{\cdot}A^{4-}$ at 7.2 < pH < 10.5. The second is identical to that of V(III). Diffusion coefficients of $VO{\cdot}HA^{2-}$ and $VO{\cdot}A^{3-}$ are found to be $(9.0{\pm}0.3){\times}10^{-6}cm^2/s$ and $(5.9{\pm}0.4){\times}10^{-6}cm^2/ses$, respectively.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.686-691
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• 2012

The objective of this research is to present method development and validation for the simultaneous determination of lutein and zeaxanthin using ultra performance liquid chromatography (UPLC). Also, rapid quantification was performed on six green leafy vegetables (Allium tuberosum, Aster scaber, Hemerocallis fulva, Pimpinella brachycarpa, Sedum sarmentosum and Spinacia oleracea) that are commonly consumed in Korea. Separation and quantification were successfully achieved with a Waters Acquity BEH C18 ($50{\times}2.1mm$, $1.7{\mu}m$) column by 85% methanol within 5 min. Two compounds showed good linearity ($r^2$ > 0.9968) in $1-150{\mu}g/mL$. Limit of detection (LOD) and quantification (LOQ) for lutein and zeaxanthin were 1.7 and 5.1 g/mL and 2.1 and 6.3 g/mL, respectively. The RSD for intra- and inter-day precision of each compound was less than 10.69%. The recovery of each compound was in the range of 91.75-105.13%. Aster scaber and Spinacia oleracea contained significantly higher amounts of lutein ($4.06{\pm}0.24$ and $3.97{\pm}0.10mg$/100 g of fresh weight), respectively.

• Archives of design research
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• v.19 no.2 s.64
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• pp.261-272
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• 2006

As we cannot think of our lives without a nation, it is closely related to almost every part of our daily lives. The role of government is becoming more important in the complex modern society as an essential element of national authority even though the government has indirect and secondary characteristics in its functional performance. Therefore, the government has to be efficient in planning and executing its policies, and it needs to be representative and fair as part of a national authoritative community. In the 21st century when symbolic and cultural importance of images are becoming more important, it is crucial for the government organizations to have an integrated identity design system that can satisfy both of these requirements of the government. However, the C.I.(Corporate Identity) of each Korean administrative branch has been developed separately and sporadically, which resulted in lack of consistency as part of the government. Shape and material of their C.I.s that follow short term design trend and popularity also lack uniqueness which can be distinguished from those of any private corporation. This may show that our government lacks systematic administrative capability, since image of a feature represents its characteristics and reality, and their recognition and evaluation from others become identity of the feature. In this perspective, the purpose of this thesis is to suggest an identity design system that has certain rules and regularity with wide variety of possible alterations for the central administration in Korea. In order to represent this visually, identity design system with both integrity and variety of possible alteration is created based on traditional Korean culture, especially the concept of Umyang-ohaeng and Samjae.

• Archives of design research
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• v.19 no.2 s.64
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• pp.241-250
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• 2006

Hangeul as the Korean unique characters were invented according to some character-making principles and based on scholars' exhaustive researches. While most of the characters in the world evolved naturally, Hangeul was invented based on a precise linguistic analysis of the time, and therefore, it is most scientific and reasonable among various characters throughout the world. Nevertheless, Hangeul typeface designs do not seem to inherit the ideology of scientific and reasonable Hangeul correctly. For the square forms have been used intact due to the influences from the Chinese characters which prevailed during the time. If a single set of square characters should be designed, as much as 11,172 fonts should be designed, which suggests that advantages of Mangeul may not well be used fully; Hangeul was invented to visualize every sound with the combinations of 28 vowels and consonants. Problems of such square fonts began to be identified since 1900's when typewriters were introduced first from the West. Since a typewriter is designed with 28 characters laid out on its keyboard by using such combinations, the letters may be easily combined on it. The so-called the flexibility square-format typeface was born as such. Specially, the three-pairs fonts of these can be combined up to 67 letters including vowels and consonants. The three-pairs fonts system can help to solve the problems arising form the conventional square fonts and inherit the original ideology of Hangeul invention. This study aims to review the history of the three-pairs fonts designs facilitated by mechanic encoding of Hangeul and thereupon, suggest some desirable directions for future Hangeul fonts. Since the flexibility square-format typeface is expected to evolve more and more owing to development of the digital technology, they would serve our age of information in terms of both functions and convenience. Just as Hunminjongum tried to be literally independent from the Chinese characters, so the flexibility square-format typeface designs would serve to recover identity of our Hangeul font designs.

• Analytical Science and Technology
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• v.13 no.4
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• pp.494-503
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• 2000

A 21-residue peptide corresponding to amino acids 84-104 of $p16^{INK4A}$, the tumor suppressor, has been synthesized and its structure was studied by Circular Dichroism, $^1H$ NMR spectroscopy and molecular modeling. A p16-derived peptide (84-104 amino acids) forming stable complex with CDK4 and CDK6 inhibits the ability of CDK4/6 to phosphorylate pRb in vitro, and blocks cell-cycle progression through G1/S phase as shown in the function of the full-length p16. Its NMR spectral data including NOEs, $^3J_{NH-H{\alpha}}$ coupling constants, $C_{\alpha}H$ chemical shift, the average amplitude of amide chemical shift oscillation and temperature coefficients indicate that the secondary structure of a p16-derived peptide is similar to that of the same region of full-length p16, which consists of helix-turn-helix structure. The 3-D distance geometry structure based on NOE-hased distance and torsion angle restraints is characterized by ${\gamma}$-turn conformation between residues $Gly^{89}-Leu^{91}$(${\varphi}_{i+1}=-79.8^{\circ}$, ${\varphi}_{i+1}=60.2^{\circ}$) as evidenced in a single crystal structure for the corresponding region of p18 or p19, but is undefined at both the N and C termini. This compact and rigid ${\gamma}$-turn region is considered to stabilize the structure of p16-derived peptide and serve as a site recognizing cyelin dependent kinase, and this well-defined ${\gamma}$-turn structure could be utilized for the design of anti-cancer drug candidates.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.83-88
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• 2005

A study was conducted on three pollination methods on oriental melon(sageageol-ggul) grafting with pumpkin(seongjutozoa) for the labor-saving and to improve fruit set. Fruit weight, flesh thickness and fruit setting rate of oriental melon were greater in growth regulators treatment than those of pollinated by bees. Sugar content and hardness of fruits pollinated by bees were higher than those of by growth regulators. From the last ten days of the February to the first ten days of the March, fruit setting rate was $95\%$ in fruit setting growth regulators, whereas it was $46\%$ and $45\%$ in pollinated by honey and bumble bee, respectively. After the middle of March, the percentage of fruit setting was >$98\%$ in all the pollination methods. The cultivation under plastic houses of oriental melon, suitable fruiting time far the pollination by bees was decided after middle days of the March. Chromaticity and especially the value of 'a' of fruit of oriental melon pollinated by bees were higher than those of growth regulators. The percentage of fermented fruits of bee pollinated and growth regulators treated was $6.7\~9.1\%\;and\;28.1\%$, respectively. The weight of 100 seeds of bees pollinated were higher than that of growth regulators. The more increased the weight of 100 seeds the less appeared the rate of fermented fruits. The percentage of marketable fruits of the honey and bumble bee pollinated and that of growth regulators treated was $82\%,\;80.3\%\;and\;62.5\%$, respectively. The decreasing rate of fruit weight during storage of bees pollinated was less than those of growth regulators. In these results, the introduction of honey bee and bumble bee for the pollination of oriental melon was able to labor-saving of fruit set and increase of fruit quality.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.647-657
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• 2015

To investigate a method for calculation of the heating load for environmental designs of horticultural facilities, measurements of total heating load, infiltration rate, and floor heat flux in a large-scale plastic greenhouse were analyzed comparatively with the calculation results. Effects of ground heat exchange and infiltration loss on the greenhouse heating load were examined. The ranges of the indoor and outdoor temperatures were $13.3{\pm}1.2^{\circ}C$ and $-9.4{\sim}+7.2^{\circ}C$ respectively during the experimental period. It was confirmed that the outdoor temperatures were valid in the range of the design temperatures for the greenhouse heating design in Korea. Average infiltration rate of the experimental greenhouse measured by a gas tracer method was $0.245h^{-1}$. Applying a constant ventilation heat transfer coefficient to the covering area of the greenhouse was found to have a methodological problem in the case of various sizes of greenhouses. Thus, it was considered that the method of using the volume and the infiltration rate of greenhouses was reasonable for the infiltration loss. Floor heat flux measured in the center of the greenhouse tended to increase toward negative slightly according to the differences between indoor and outdoor temperature. By contrast, floor heat flux measured at the side of the greenhouse tended to increase greatly into plus according to the temperature differences. Based on the measured results, a new calculation method for ground heat exchange was developed by adopting the concept of heat loss through the perimeter of greenhouses. The developed method coincided closely with the experimental result. Average transmission heat loss was shown to be directly proportional to the differences between indoor and outdoor temperature, but the average overall heat transfer coefficient tended to decrease. Thus, in calculating the transmission heat loss, the overall heat transfer coefficient must be selected based on design conditions. The overall heat transfer coefficient of the experimental greenhouse averaged $2.73W{\cdot}m^{-2}{\cdot}C^{-1}$, which represents a 60% heat savings rate compared with plastic greenhouses with a single covering. The total heating load included, transmission heat loss of 84.7~95.4%, infiltration loss of 4.4~9.5%, and ground heat exchange of -0.2~+6.3%. The transmission heat loss accounted for larger proportions in groups with low differences between indoor and outdoor temperature, whereas infiltration heat loss played the larger role in groups with high temperature differences. Ground heat exchange could either heighten or lessen the heating load, depending on the difference between indoor and outdoor temperature. Therefore, the selection of a reference temperature difference is important. Since infiltration loss takes on greater importance than ground heat exchange, measures for lessening the infiltration loss are required to conserve energy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1139-1145
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• 2006

In this study, antioxidant activities of enzymatic and methanolic extracts from E. cava stem and leave were evaluated by measuring the scavenging activities on 1,1 diphenyl 2 picrylhydrazyl (DPPH), hydroxyl radical, hydrogen peroxide and the inhibitory effects on DNA damage induced by oxidative stress of cells. Enzymatic extracts were prepared by enzymatic hydrolysis of both stem and leave using food grade five different carbohydrases (Viscozyme, Celluclast, AMG, Termamyl, Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme, Alcalase). The enzymatic extracts were lower than methanolic extracts in polyphenol contents, but higher in extraction yield by approximately 30%. The enzymatic extracts were superior to methanolic extracts in DPPH and H2O2 scavenging activities and DNA damage protective effect. There were no significant antioxidant activity difference between stem and leave, but the extracts of leave were relatively better than those of stem. In this study it is suggested that E. cava stem as well as its leave would be a good raw materials for antioxidants compound extraction and enzymatic hydrolysis would be a good strategy to prepare antioxidant extracts from seaweeds.