• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.45-45
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• 2000

PDP, FED, 그리고 VFD와 같은 마이크로 전자디스플레이 장치를 제작하기 위한 가장 중요한 기술중에 하나인 패널 내를 고진공으로 만드는 것과 초기의 진공을 유지하는 것이다. PDP 디스플레이는 전면판과 후면판으로 구성되어 있다. 전면판은 ITO전극, 절연체 그리고 MgO보호막으로 구성되어 있으며, 후면판은 어드레스 전극, 반사층, 격벽, 그리고 형광체층이 있다. 기존의 방식은 대기에서 프릿 글라스를 이용하여 두 장의 유리를 봉입하고, 후면판 모서리 부분에 있는 구멍에 배기 글라스 튜브를 붙이고, 튜브를 통해서 배기하고, 플라즈마 가스를 채우고, 최종적으로 tip-off를 한다. 이러한 기존의 방식을 통해서는 배기 컨덕턴스의 한계로 얻을 수 있는 초기 진공도에 한계가 있다. 아울러 두 장의 유리사이는 150$\mu$m 정도의 간격으로 되어 있고, 이웃한 격벽사이는 320$\mu$m 정도의 미세한 공간이 주어지는 구조가 컨덕턴스를 저하시킨다. 이와 같은 초기 진공도의 한계성을 극복하기 위한 연구로서, PDP 패널을 구성하는 두 장의 글라스를 진공 챔버내에서 IR heater를 이용하여 실장하였다. 대개 PbO, ZnO, SiO2,, 그리고 B？로 구성된 프릿 글라스를 대기에서 전면판에 dispensing하고 가소한다. 그리고 프릿 글라스가 형성된 전면판과 후면판을 loading, align 한 다음, 2 10-7torr까지 펌핑한 후 heating, holding 그리고 cooling 공정을 수행하므로 써 두 장의 유리를 실장하였다. 그러나 온도의 non-uniformity, 프릿 성분에 따라서 crack과 기포문제가 진공 실장과정에서 발생하였다. 이와 같은 문제를 개선하기 위해 프릿 글라스의 새로운 조성과 온도 uniformity를 유지하므로써, 프릿 글라스의 기포와 crack 발생없이 재현성 있게 진공 실장하였다. Leak channel 형성유무를 검증하기 위하여 챔버 자체의 펌핑 속도와 제작된 패널의 펌핑 속도를 비교하므로써, leak channel형성 유무를 평가할 수 있는 방법을 이용하였다. 이와 같은 방법을 이용하여, crack 또는 기포가 있는 패널은 leak channel을 형성하여 패널내의 진공을 유지할 수 없음을 검증하였고, crack 또는 기포가 없는 패널은 leak channel없이 패널내의 진공을 유지할 수 있음을 검증하였다. 결과적으로 진공 인-라인 실장시 가장 중요한 요인인 프릿의 변화를 분석하므로써, 고진공을 요구하는 FPD(PDP, FED, VFD)에 적합하게 적용할 수 있으며, 아울러 실장시 진공도를 개선하므로 패널내부의 오염을 최소화하여 디스필레이로서의 효율을 극대화할 수 있을 것이다.

• 한국재료학회지
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• 제25권10호
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• pp.552-558
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• 2015

The mechanical properties and microstructures of Aluminum 6056 alloys were investigated for their use in the fabrication of a piton block. The EN-AW6056 alloys exhibited a tensile strength of 375 MPa for a solution treatment temperature of $550^{\circ}C$ for 2 h followed by an aging treatment at $190^{\circ}C$ for 4 h. The microstructures of the heat treated specimen showed that the $Mg_2Si$ phase with a size of 3~5 um was dispersed throughout the aluminum matrix when the heat treatment was done. Moreover, in order to identify the forgeability of the specimen, upsetting tests were done. For up to 80 % of the upsetting ratio, the specimen maintained its original shape, and at above 80 % of the upsetting ratio, the specimen underwent crack development. The specimen was successfully forged without any defects with the examined material conditions. The material conditions together with the forging conditions are discussed in terms of the microstructures and mechanical properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 학술대회 및 기술세미나 논문집 디스플레이 광소자
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• pp.78-80
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• 2006

The hybrid thin-film (HTF) passivation layer composed of the Ultra Violet (UV) curable acrylate layer and MS-31 (MgO:$SiO_2$=3:1wt%) layer was adopted in organic light emitting device (OLEO) to protect organic light emitting materials from penetrations of oxygen and water vapors. The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007gm/m^{2+}day$ at $37.8^{\circ}C$ and 100% RH. This value was within the limited range of the sensitivity of WVTR measurements. And the lifetime of the HTF passivated device became almost three times longer than that of the bare device. The HTF on the OLEO was found to be very effective in protect what from the penetrations of oxygen and moisture.

• 한국표면공학회지
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• 제54권5호
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• pp.238-247
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• 2021

PEO (plasma electrolytic oxidation) was applied to modify the surface of AZ31 magnesium alloy in this study. The mixed solution of sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) was used as the electrolyte, and 0 - 0.05 g/L of Ca-GP (Glycerol Phosphate Calcium salt) was added in the electrolyte as an additive. PEO treatment was conducted at a current density of 30mA/cm² for 5 minutes using a DC power supply. The surface properties were identified by SEM, XRD and surface roughness analyses, and the corrosion resistance was evaluated by potentiodynamic polarization and immersion tests. In addition, the biocompatibility was evaluated by immersion test in SBF solution. As the concentration of Ca-GP was increased, the surface morphology was denser and more uniform, and the amount of Ca and the thickness of oxide layer increased. Only Mg peak was observed in XRD analysis due to very thin oxide layer. The corrosion resistance of PEO-treated samples increased with the concentration of Ca-GP in comparision with the untreated sample. In particular, the highest corrosion resistance was identified at the group of 0.04g Ca-GP through potentiodynamic polarization and immersion tests in saline solution (0.9 wt.%NaCl). During the immersion in saline solution, pH rapidly increased at the beginning of immersion period due to rapid corrosion, and then increase rate of pH decreased. However, the pH value in the SBF temporarily increased from 7.4 to 8.5 during the day, then decreased due to the inhibition of corrosion with HA(hydroxyapatite) formation.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.282-293
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• 2021

This paper examines gamma-ray shielding properties of SBC-Bx glass system with the chemical composition of 40SiO₂-10B₂O₃-xBaO-(45-x)CaO- yZnO- zMgO (where x = 0, 10, 20, 30, and 35 mol% and y = z = 6 mol%). Mass attenuation coefficient (µ/ρ) which is an essential parameter to study gamma-ray shielding properties was obtained in the photon energy range of 0.015-15 MeV using PHITS Monte Carlo code for the proposed glasses. The obtained results were compared with those calculated by WinXCOM program. Both the values of PHITS code and WinXCOM program were observed in very good agreement. The (µ/ρ values were then used to derive mean free path (MFP), electron density (N_eff), effective atomic number (Z_eff), and half value layer (HVL) for all the glasses involved. Additionally, G-P method was employed to estimate exposure buildup factor (EBF) for each glass in the energy range of 0.015-15 MeV up to penetration depths of 40 mfp. The results reveal that gamma-ray shielding effectiveness of the SBC-Bx glasses evolves with increasing BaO content in the glass sample. Such that SBC-B35 glass has superior shielding capacity against gamma-rays among the studied glasses. Gamma-ray shielding properties of SBC-B35 glass were compared with different conventional shielding materials, commercial glasses, and newly developed HMO glasse. Therefore, the investigated glasses have potential uses in gamma shielding applications.

• 한국버섯학회지
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• 제20권1호
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• pp.13-21
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• 2022

Cordyceps militaris, a well-known traditional Chinese medicine, has multiple health-promoting effects. It is used as a herbal remedy and health food in Asian countries. Cultured mycelia are often used as a substitute for natural C. militaris. In the present study, the mycelia and fruiting bodies of artificially cultured C. militaris were analyzed using a metabolomics approach. The protein and crude fat contents of the mycelia were substantially higher than those of the fruiting bodies. The top three abundant amino acids in the mycelia were proline (3.9 g/100 g), aspartic acid (2.9 g/100 g), and glutamic acid (2.7 g/100 g). The carbohydrate content was similar in the fruiting bodies and mycelia. Analysis revealed that both the fruiting bodies and mycelia are rich in phenolic compounds and exhibit antioxidant activity. Further, six metabolites were significantly different between the mycelia and fruiting bodies. The levels of Ca, glucose, Mg, and Se were higher in the mycelia than in the fruiting bodies. In contrast, mannitol and Zn were more abundant in the fruiting bodies. The current study provides a comprehensive metabolic profile of the mycelia and fruiting bodies of artificially cultured C. militaris. Such an exercise is potentially important for understanding the metabolism of C. militaris and facilitating the use of cultured mycelia as a supplement to C. militaris fruiting bodies in traditional Chinese medicine.

• 한국균학회지
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• 제47권4호
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• pp.359-371
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• 2019

큰느타리버섯에서 철 저장과 관련된 페리틴 단백질의 발현 및 분비를 최적화하기 위해, T-Fer 벡터에 EcoRI 및 HindIII처리를 해 페리틴 유전자를 얻은 후, BamHI으로 처리된 선형의 pPEVPR1b 분비 벡터에 클로닝하여pPEVPR1b-Fer 재조합 벡터를 구축한 다음 Agrobacterium tumefaciens LBA4404 로 도입하였다. Agrobacterium tumefaciens-mediated transformation 방법에 의해 Pleurotus eryngii로 형질전환하고 kanamycin함유된 MCM 배지에서 올바른 형질전환체를 선별하였고, 단백질 발현은 SDS-PAGE 및 항원항체 반응에 의한 western blot으로 확인하였다. 페리틴 단백질의 분비 발현은 batch culture 및 20 L airlift type fermenter에서 배양 시간 및 온도와 같은 배양 조건에 의해 최적화되었다. 페리틴 생산을 위한 배양 조건은 MCM 배지에서 25℃ 및 8 일 배양에 의해 최적화되었다. 페리틴 단백질의 양은 정량적 단백질 분석에 의해 2.4 mg/g mycelium으로 측정되었다. 그러나, PR1b (32 amino acid)의 분비서열은 큰느타리버섯 내부의 peptidase에 의해 정확하게 processing되지 않았지만, 페리틴 단백질은 균사체에서 최대로 전체단백질의 24.7% 발현되었고, 배양액에서는 검출되지 않았다. 철 결합 활성은 7.5% non-denaturing gel에서 Perls' staining에 의해 확인되었으며, 다량체 페리틴(24 subunits)이 P. eryngii 균사체에서 형성되었음을 보여준다. 생물학적 활성 측정을 위하여 페리틴을 함유한 분말을 제조하여 육계의 사료 첨가제로서의 사용 가능성에 대해 시험하였으며, 결과적으로 페리틴은 육계의 성장을 촉진하고 사료 효율 및 생산 지수를 향상시키는것으로 확인되었다.

• The Korean Journal of Ecology
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• 제24권2호
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• pp.101-109
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• 2001

We created an environmental forest on the basis of ecological design around the incineration plant of Jindo Engineering and Construction Co., Ltd., which is located in Jeongwang-dong, Siheung-si, Kyunggi-do. To get ecological information of this site, physico-chemical properties of soil on salt marsh, which is located close to the syudy site and of forest soil transported from other sites for ecological restoration were analyzed. Texture of salt marsh and transported soils were loam and sandy loam, respectively. pH, organic matter, T-N, available P, and exchangeable K and Na contents of salt marsh and transported forest soils were 6.7 and 5.4, 4.1 and 0.4%, 1.0 and 0.3mg/g, 46.7 and 6.8ppm, 521 and 207ppm, and 3.8 and 0.5mg/g, respectively. Introduced plants were selected among the dominant species of forests and the species composing the potential natural vegetation around the present study site. Those plants were selected again by considering the tolerances to air pollution and to salt, and their availability. Selected trees were Pinus thunbergii, Sophora japonica, Celtis sinensis, Quercus aliena, Q. serrata, Q. dentata, and Q. acutissima. Selected sub-trees were Albizzia julibrissin, Koelreuteria poniculata, and Styrax japonica and shrubs were Rhododendron yedoense var. poukhanense, R. mucronulatum, Callicarpa japonica, Euonymus alatus, E. japonica, and R. schlippenbachii. On the other hand, introduction of herbs was not considered except for Liriope platyphylla, which was ornamentally planted in one site. Planting bed of mound type was adopted to provide the fine drainage system. Mound was designed to furnish litter, A, B, and C layers simuating the profile of forest soil. Slope of mound was mulched by rice straw of 2cm in thickness to prevent for sliding of litter and soil in cases of strong wind or heavy rain. Height of mound was designed to secure more than 1 m by combining A and B layers. Narrow zones, in which mound with stable slope degree cannot be prepared, was designed to equip the standard soil depth with the introduction of stone for supporting. On the other hand, plants with shallow root system were arranged in some zones, in which satisfactory soil depth cannot be ensured. Plants were arranged in the order of tree, sub-tree, and shrub from center to edge on the mound to make a mature forest of a dome shape in the future. Dispersion of plants was designed to be random pattern rather than clumped one. Problems on creation of the environmental forest by such ecological design were found to be management or inspection by non-specialized project operators and inspecting officers, and regulations for construction without ecological background. Alternative plans to solve such problems were suggested.

• 한국환경농학회지
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• 제30권2호
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• pp.173-178
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• 2011

본 연구에서는 불가사리 폐기물을 농업용 소재로서 활용 가능성을 조사하기 위해 불가사리 생체의 유기용매 추출물을 이용하여 복숭아혹진딧물 살충효율 실험을 수행하였다. 불가사리 추출물은 1,000 mg/L 수준에서 약 70% 이상의 살충효율을 보였으며 추출물을 정제하여 TOF-MS 분석한 결과 살충물질로서 polyhydroxysteroid가 동정되었다. Polyhydroxysteroid는 진딧물의 cuticle membrane을 파괴하여 진딧물을 살충하는 기작을 보유하고 있는 것으로 투과전자현미경 분석결과 밝혀졌다. 본 연구를 통해 폐기물 형태로 퇴치되고 있는 불가사리를 활용하면 진딧물 같은 해충방제용 소재로서 개발할 수 있을 것으로 기대되었다.

• 한국식품과학회지
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• 제37권2호
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• pp.199-205
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• 2005

본 연구는 제빵 산업의 현장에서 제빵적성 향상을 위한 제빵법을 확립하기 위하여 백국균을 이용한 밀가루 코지, 유산균, 효모를 혼합 배양하여 seed mash를 만들어 그 특성을 분석하였다. 증류수 560mL와 코지 400g을 혼합하여 $25^{\circ}C$에서 72시간 배양한 seed mash의 효소 활성을 측정한 결과는 ${\alpha}-amylase$는 0.26 SKB/g, saccarifying amylase 활성이 36SP/g,그리고 산성 protease 활성은 648 HUT/g을 나타냈다. 코지, 유산균, 효모를 배양하여 제조한 seed mash의 pH는 코지와 효모 만을 배양하여 제조된 seed mash보다 다소 낮았다. 배양기간에 따른 환원당의 변화는 코지만을 이용한 seed mash의 경우 36시간까지 배양기간이 증가함에 따라 증가하였으며, 그 이후 감소하였다. 그러나 유산균과 효모를 첨가한 seed mash에서의 환원당은 배양 6시간까지 증가하다 그 이후 급격히 감소하였다. Seed mash에서 생성된 총산의 양은 10.4-12.25mg/mL로 유산균을 첨가시 다소 높았다. 코지, 효모, L. brevis로 배양한 seed mash에서 ethyl acetate, ethyl caprylate, isoamyl acetate, ethyl caprate, p-vinyl guaiacol 등의 향기 성분이 검출되었다.