Bonding Wire 파괴력 자동 측정 시스템

유슬기,김용구,우승표,고국원,박윤창 제어로봇시스템학회 2013 제어로봇시스템학회 국내학술대회 논문집 Vol.2013 No.5

아밀로이드 베타(amyloid beta)로 유도된 인지장애 마우스 모델에서 갑주백목(Diospyros kaki) 추출물의 인지기능 및 뇌 신경세포 보호 효과

유슬기,김종민,박선경,강진용,한혜주,박효원,김철우,이욱,허호진 한국식품과학회 2019 한국식품과학회지 Vol.51 No.4

The current study investigated the effect of Gabjubaekmok (Diospyros kaki) ethanolic extract (GEE) on H2O2- induced human neuroblastoma MC-IXC cells and amyloid beta (Aβ)1-42-induced ICR (Institute of Cancer Research) mice. GEE showed significant antioxidant activity that was evaluated based on ABTS, DPPH scavenging activity, and inhibition of malondialdehyde (MDA) and acetylcholinesterase activity. Further, GEE inhibited ROS production and increased cell viability in H2O2-induced MC-IXC cells. Administration of GEE ameliorated the cognitive dysfunction on Aβ-induced ICR mice as evaluated using Y-maze, passive avoidance, and Morris water maze tests. Results of ex vivo test using brain tissues showed that, GEE protected the cholinergic system and mitochondrial functions by increasing the levels of antioxidants such as ROS, mitochondrial membrane potential (MMP), and adenosine triphosphate (ATP) against Aβ-induced cognitive dysfunction. Moreover, GEE decreasd the expression levels of apoptosis-related proteins such as TNF-α, p-JNK, p-tau, BAX and caspase 3. While, expression levels of p-Akt and p-GSK3β increased than Aβ group. Finally, gallic acid was identified as the main compound of GEE using high performance liquid chromatography.

에밀리 디킨슨과 동양

유슬기,권승혁 한국현대영미시학회 2019 현대영미시연구 Vol.25 No.2

While it is well known that some American writers, such as Ralph Waldo Emerson, Henry David Thoreau, Walt Whitman, and so on had great enthusiasm for the East, Emily Dickinson has been an exceptional American poet who does not deal with any topic on the East. She seemed to have a reclusive life and have no interest in the East, however, recent studies by Cristanne Miller, Yanbin Kang, and other Dickinson scholars have revealed that she had also a keen interest in the East, and wrote some poems on it. On the basis of these recent studies on Dickinson and the East, this paper is going to investigate the ways in which she encountered and invented the East in her poetic works, and articulate its meaning and significance. Her visit to the Chinese Museum at the Malboro’ Chapel of Boston at her age of sixteen, her life-long gardening of the Asian flowers at her homestead, her intensive readings on the East in Emerson’s Poems, Thomas Wentworth Higginson’s publications in The Atlantic Monthly and the various news on the East in The Springfield Republican helped her shape her own idea on it. She usually visualized the East as a spectacular sunrise, but transformed its stereotypical idea of her contemporaries into a revolutionary one. Her imaginative idea on the East challenges not only the puritanical ideas on death but also the imperialistic idea on the East. As her use of the punctuation marks, lineation, and fascicles makes her poems distinctive, her concept on the East gives her work a rich and significant dimension.

Improving Signal Integrity by Reducing Mode Conversion in Differential Pairs on a Meshed Ground in Flexible Printed Circuit Boards

유슬기,감동근 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.3

Asymmetry in a differential pair leads to deterioration of signal integrity. Differential pairs on a meshed ground often encounter asymmetry in return current paths. In this paper, we propose an offset mesh as an improved mesh structure that offsets asymmetry between a solid region and an aperture region. The offset mesh mitigates the asymmetry in the conventional mesh structure without additional design elements. The proposed structure has been verified to be effective in reducing mode conversion, intra-pair and inter-pair skews, and characteristic impedance variation in the time and frequency domains. This enables high-density routing of differential pairs.

근대도시 경성에서의 토지가격 결정 요인 연구 - 동부지역을중심으로 -

유슬기 서울대학교 환경대학원 2022 環境論叢 Vol.70 No.-

Stable Superhydrophobic PVDF-grafted Cellulose Membrane for Oil/Water Separation

유슬기,방준하,허윤 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

A PVDF-grafted cellulose membrane (PVDF-g-CM) is prepared as a superhydrophobic membrane for oil/water separation. Surface-initiated grafting polymerization of PVDF was carried out via RAFT/MADIX of PVDF on a RAFT CTA-attached cellulose membrane. PVDF is a hydrophobic fluoropolymer, with low surface energy from the two C-F bonds. Due to the widely known chemical and thermal stability of PVDF, PVDF is a promising candidate as a grafting material for oil/water separation. The superhydrophobic PVDF-g-CM showed a WCA of ~150° and used as a separation membrane for oil/water mixtures. PVDF-g-CM showed high separation efficiencies after multiple cycles and also showed physical, chemical, and thermal stability, compared to the PVDF-coated CM.

잔대(Adenophora triphylla var. japonica)순 아세트산에틸 분획물의 피부 미백 효과

유슬기,박선경,강진용,김종민,박상현,권봉석,이창준,강정은,박수빈,이욱,허호진 한국자원식물학회 2017 한국자원식물학회지 Vol.30 No.4

To investigate skin-whitening effect of Adenophora triphylla var. japonica sprout extract, antioxidant activity, inhibitory effect on tyrosinase and melanin synthesis in B16/F10 melanoma cell were examined. Total phenolic content (246.25 ㎎ GAE/g) and total flavonoid content (303.94 ㎎ RE/g) of ethyl acetate fraction from Adenophora triphylla sprout (EFAT) showed the highest contents than other fractions (n-hexane, chloroform and distilled water). Antioxidant activities of EFAT has been evaluated using ABTS, DPPH radical scavenging activities, FRAP and inhibitory effect of lipid peroxidation. EFAT showed excellent radical scavenging activity and inhibitory effect on MDA production. Inhibitory effect of tyrosinase as a major enzyme of melanin synthesis was also measured. In these results, EFAT showed higher inhibitory effect against L-DOPA (51.27%) than L-tyrosine. IC50 value on α-glucosidase was 41.93 ㎍/㎖. In B16/F10 melanoma cells, EFAT inhibited melanin synthesis at 200 ㎍/㎖ concentration (about 42% decrease). Finally, main physiological compounds of EFAT were identified as a rutin and a chlorogenic acid using high performance liquid chromatography. 본 연구에서는 잔대(Adenophora triphylla var. japonica)순아세트산에틸 분획물의 in vitro 미백 효과에 대하여 연구하였다. EFAT는 다른 분획물과 비교하여 뛰어난 총 폴리페놀 함량(246.25 ㎎ GAE/g)과 총 플라보노이드 함량(303.94 ㎎ RE/g) 을 나타내었으며, ABTS, DPPH 라디칼 소거 활성, FRAP assay 및 MDA 억제 활성에서 상대적으로 우수한 항산화 활성을 보였다. EFAT는 α-glucosidase 억제 활성에서 41.93 ㎍/㎖의 IC50 값을 나타내었으며, L-DOPA를 기질로 이용한 tyrosinase 억제 활성의 IC50은 438.67 ㎍/㎖로 tyrosinase의 산화 반응을 효과적으로 억제하는 것으로 나타났다. 또한 B16/F10 melanome 세포에서 α-MSH에 의해 유도된 멜라닌을 200 ㎍/㎖의 농도에서 108.04%로 높은 저해 효과를 보여주었다. 따라서 EFAT는α-glucosidase 억제 효과를 통한 tyrosinase의 glycosylation 을 저해 작용과 tyrosinase의 가역적인 산화반응 저해를 통한멜라닌의 생성을 억제하는 것으로 사료된다. 마지막으로 EFAT 의 생리활성 물질을 확인하기 위해 HPLC 분석을 실시한 결과, 주요 생리활성 물질은 chlorogenic acid와 rutin으로 추정되었다. 이러한 연구 결과를 바탕으로 볼 때, EFAT는 자외선 등으로부터 발생되는 산화적 스트레스로 발생되는 멜라닌의 생합성저해 효과를 통하여, 미백 기능성을 함유한 향장소재로의 이용가능성이 높다고 판단되어진다.

Analysis of Energy Efficiency of Light-Weigh Wood Frame House and Wooden Passive House Using PHPP

유슬기,김석환,서정기,김수민 ARCHITECTURAL INSTITUTE OF KOREA 2013 大韓建築學會論文集 : 構造系 Vol.29 No.8

공간계량모형으로 살펴본 경성 동부지역 토지시장 연구

유슬기,김경민,김진석,이지상 한국경제지리학회 2022 한국경제지리학회지 Vol.25 No.4

In this study, the land market in Eastern District of Gyeongseong is examined using land price data in the 1920′s. For the study, land information in 1927 is constructed as a DB, and a map in 1929 is constructed as a GIS file to realize digitalization of historical data. As a result of the study, it is confirmed that spatial autocorrelation exists, and through spatial econometrics analysis, some factors affecting the modern land market are also valid at that time. The results show that land use and road accessibility have a positive effect on the land market, while the proximity of anchor facilities and educational facilities have a negative effect. This study is meaningful in that it has moved on to a research topic that has been insufficient until now by examining whether the factors operating in the land market in the 21st century are also valid in the land market in the 1920′s. 본 연구에서는 1920년대 토지가격 정보를 활용하여 경성 동부지역의 토지시장을 살펴보았다. 연구를 위하여 1927년 경성부관내지적목록 토지정보를 DB로 구축, 1929년 지형명세도를 GIS 파일로 구축해 역사 자료의디지털화를 실현하였다. 연구 결과, 공간자기상관성이 존재함을 확인하였고, 공간계량분석을 통해 현대 토지시장에서 영향을 주는 요인들이 당시에도 일부 유효한 것으로 확인되었다. 토지용도와 대로 접근성이 토지시장에긍정적 영향을 주는 반면, 앵커시설 및 교육시설 인접 여부는 부정적 영향을 준다는 결과가 도출되었다. 본 연구는 21세기 현재 토지시장에서 작동하는 요인들이 1920년대 토지시장에서도 유효한지를 살펴봄으로써 그동안미비했던 연구주제로 나아갔음에 의의가 있다.

담배 판매량 구조변화 추정을 통한 금연정책 효과성 분석

유슬기,홍우형 한국재정정책학회 2022 財政政策論集 Vol.24 No.3

In this paper, we evaluate the effect of tobacco control policies by estimating structural breaks in the tobacco market from January 2013 to December 2021 using Nielsen tobacco sales data. We divide the tobacco market into conventional cigarettes and Heated Tobacco Products (HTPs) markets and estimate the structural breaks of each market using Bai and Perron (1998, 2003) and Ditzen et al. (2021) methods. The empirical results show that tax-induced price increase in 2015 leads to the main structural break in the conventional cigarette market. In addition, the introduction of HTPs and COVID-19 epidemic affect the trend of conventional cigarette consumption. The structure breaks in HTP market are observed due to the controversy over the dangers of e-cigarettes and COVID-19, but the increased tax for HTPs enacted in 2018 has no effect on the sales trend. It means that only dramatic price hike is valid to reduce cigarette consumption, and moderate price increase or other non-price policies, such as warning pictures on cigarette packs and smoke-free legislation do not permanently decrease cigarette consumption. 본 연구는 닐슨 담배판매량 자료를 사용하여 2013년 1월부터 2021년 12월동안담배시장의 구조변화를 추정하여 금연정책이 담배소비에 유의한 영향을 미쳤는지 분석하였다. 이때, 담배를 일반궐련과 궐련형 전자담배로 구분하여 각 자료에서 나타난 구조변화를 추정하였다. 추정방법은 월단위 시계열자료에 대해 Bai and Perron (1998, 2003)을, 시도 패널자료에서는 Ditzen et al.(2021) 방법론을 적용하였다. 실증분석 결과, 일반궐련은 개별소비세가 도입된 2015년 1월을 전후로 구조전환점이 발생하였으며, 이후에도 궐련형 전자담배 도입 및 COVID-19 감염병 사태 등의 영향으로 구조변화가 발생하였다. 이는 분석기간에 정부에서시행한 담뱃갑 경고그림 표기, 금연구역 확대 등의 다른 비가격정책이 담배 소비에 구조적 변화를 야기하지 못했음을 의미한다. 궐련형 전자담배 또한 전자담배위해성 논란 및 COVID-19 감염병 사태로 인한 구조적 변화만 관측되었으며, 2018년 궐련형 전자담배 가격인상이나 다른 비가격정책은 담배 소비에 구조적인영향을 미치지 못했음을 확인하였다. 종합하면, 본 연구의 결과는 금연정책 중급격한 가격인상만이 담배 소비를 영구적으로 감소시킬 수 있었으며, 미미한 가격 인상이나 다른 비가격정책은 담배 소비에 구조적 변화를 유의미한 영향을 미치지 못하였다는 근거를 제시한다.