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Seung-Yeop Song,Myung-Suk Ahn,Eun-Mi So,Jae-A Jung,Hyun-Young Song,Oh-Keun Kwon 한국원예학회 2021 한국원예학회 학술발표요지 Vol.2021 No.10
The antioxidant activity of extracts from 5 Aster species was studied to investigate the potential Aster species as functional raw materials. In this study, we used five kinds of Aster species, including Aster yomena, Aster arenarius, Aster glehnii, Aster altaicus, and Aster meyendorfii, which were grown in non-heated plastic film house and harvested in November 2020. The extraction yields, total phenolic contents, total flavonoid contents and DPPH and ABTS radical scavenging capacities were investigated. The highest extraction yield was obtained in 70% ethanol extraction using Aster glehnii. The total phenolic content was the highest in the extract of Aster glehnii, and the total flavonoid content was the highest in that of Aster arenarius among 5 Aster species. In DPPH and ABTS radical scavenging assay, the antioxidant capacities were expressed as ascorbic acid and BHA equivalents (VCE, BHAE). The highest DPPH scavenging capacity was observed in Aster glehnii, and ABTS scavenging capacity was highest in that of Aster meyendorfii. The result of the experiment was different depending on the species, and these results among 5 Aster species may provide that it can be used as a basic data for the development of functional materials for plants of the Aster species.
S20C 리벳된 Al5052와 SPFC980Y 강철 resistance-element 점용접 접합부의 미세조직 발달 및 고강도-부식 저항 특성
백승엽(Seung-Yeop Baek),송종호(Jong-Ho Song),박승연(Seung-Youn Park),송일종(Il-Jong Song),이현철(Hyun-Chul Lee) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.2
이 연구는 electric resistance element spot welding 프로세스를 도입하여 알루미늄 합금-강철의 이종 접합부의 기계적 강도 및 내식성을 향상시키기 위해 수행되었다. SPFC980Y 강철과 Al5052-H32가 각각 모재로써 적용되었고, S20C 강철은 리벳 element로써 음각과 양각의 형상으로 구분되며, Al5052-H32에 전기 저항 스폿 용접을 위해 리벳팅 되어 6.5 kA의 전류와 250 kgf/cm²의 가압력으로 접합되었다. 그 결과, 음각된 S20C element는 스폿 용접공정 후 불안정한 너깃이 형성되는 반면, 양각된 S20C의 경우, 구조적으로 건전한 접합부로 건전한 내식성 및 탁월한 기계적 특성이 얻어졌다. FEM 시뮬레이션의 도입으로, 음각과 양각의 계면의 접합 특성이 수치적으로 밝혀졌으며, 시뮬레이션 결과는 미세조직 발달 양상을 수치적으로 뒷받침하였다. 이 연구는 element 스폿 용접된 H32-A5052 이종 접합부의 기계적 강도 및 부식 신뢰성에 대해 체계적으로 분석되었으며, 이 공정은 금속재료뿐만 아니라, 경량 비전도성 비철/비금속계 재료에도 적용 될 수 있기 때문에, 차세대 차체 경량화의 양산 기술로 확장 될 수 있다. This study examined the mechanical strength and corrosion resistance of a dissimilar joint with an aluminum alloy and steel by resistance element spot welding. SPFC980 steels and Al5052 alloys were applied as the base materials. S20C steels were assembled on Al5052 for the riveting element before the electric resistance welding process. The SPFC980-S20C riveted Al5052 was welded at a 6.5 kA current and 250 kgf/cm². As a result, the engraved S20C elements formed unstable nuggets after the spot welding processes. In contrast, in the embossed S20C elements, exceptional mechanical properties, such as robust corrosion resistance and fatigue resistance, were obtained by structurally sound joints. The correlation between the microstructure and mechanical properties were examined by microstructural investigations and FEM simulations. The corrosion reliability of element spot-welded SPFC980-Al5052 dissimilar joints was investigated systematically.
EMIP를 이용한 인버터 구동 고압 유도전동기의 스위칭 써지 특성 분석
송승엽(Song Seung-Yeop),김재철(Kim Jae-Chul),신중은(Shin Joong-Eun),권영목(Kwon Young-Mok),황돈하(Hwang Don-Ha) 한국조명·전기설비학회 2004 한국조명·전기설비학회 학술대회논문집 Vol.2004 No.5월
The PWM inverter drive may cause motor terminals voltage surge and oscillation(ringing), which impose severe electric stresses on inter-turn insulation of motor windings. This paper describes the technique used to simulate the problems associated with the use of PWM ASD"s(Adjustable Speed Drive) to drive induction motor. The characteristic of switching surge was analyzed by EMTP(Electromagnetic transient program) model. The effects of switching surge by surge impedance, rise-time and cable lengths are also discussed.
Song, Young Geun,Park, Jae Yeol,Suh, Jun Min,Shim, Young-Seok,Yi, Seung Yeop,Jang, Ho Won,Kim, Sangtae,Yuk, Jong Min,Ju, Byeong-Kwon,Kang, Chong-Yun American Chemical Society 2019 Chemistry of materials Vol.31 No.1
<P>The use of heterojunctions based on Rh-decorated WO<SUB>3</SUB> nanorods is an effective strategy for achieving high-performance gas sensors for volatile organic compounds (VOCs), especially acetone (CH<SUB>3</SUB>COCH<SUB>3</SUB>). Herein, we successfully fabricated Rh-decorated WO<SUB>3</SUB> nanorods with one-dimensional (1D) structures by glancing angle deposition (GLAD). Interestingly, morphological changes characterized by anomalous surfaces with numerous regions of negative curvature were observed upon decoration of the bare WO<SUB>3</SUB> nanorods with Rh, which were systematically investigated on the basis of impeded surface diffusion and trapping effects. The improvements of gas sensing properties were stepwisely demonstrated by synergistic effects involving transition of Rh, high chemical potential of the negative curvature, primary decomposition at the top side, and highly ordered nanostructures. We are confident that the results provide new insight into the synthesis of effective nanostructures and contribute to a variety of applications including battery, solar water splitting, and sensor devices.</P> [FIG OMISSION]</BR>
Seung Yeop Baek,Na Rae Lee,Da Hye Kim,Ayoung Gu,Seong Yeol Kim,Dae-Yong Song,김동희,Hak Joo Choi,Byung-Jun Park,김인식 대한독성 유전단백체 학회 2015 Molecular & cellular toxicology Vol.11 No.2
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons in the substantia nigra pars compacta. In this study, we investigated the effects of a novel herb formula, Hepad, on PD. Dose-dependent treatment with 1-methyl-4-phenylpyridinium (MPP+) decreased the viability of SH-SY5Y cells, and Hepad inhibited the toxic effect of MPP+. Hepad blocked the production of reactive oxygen species (ROS) induced by MPP+ in SH-SY5Y cells, and suppressed the activation of caspase 9 and caspase 3 due to MPP+. A rat model of PD was generated by 6-hydroxydopamine (6-OHDA) injection into the left medial forebrain bundle (MFB) of SD rats. In D-amphetamine sulfate-induced rotational behavioral tests, Hepad administration attenuated circling behavior relative to the 6-OHDA-treated disease group. In addition, Hepad treatment significantly increased the tyrosine hydroxylase (TH)-positive cells in the substantia nigra pars compacta (SNpc) that had decreased in response to 6-OHDA treatment (P<0.05). OX-6 expression, which indicates the presence of microglial cells, decreased significantly after treatment of Hepad in contrast to the 6-OHDA-treated disease group (P<0.05). These results indicate that Hepad may be a useful neuroprotective material for the treatment of neurodegenerative disorders such as PD.