Degradation mechanism of polyethylene separators in lithium-ion batteries after prolonged cycling

하예지,최윤정,최정인,박보근,양진혁,김기재 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.3

The degradation of lithium-ion batteries (LIBs) is caused by a complicated mechanism; therefore, identifying their degradation mechanism remains challenging. Most studies related to the degradation mechanism of LIBs have focused on the degradation of cathode and anode materials. A separator that provides a pathway for Li+ ions is crucial for good electrochemical performance and safety of LIBs, but its degradation mechanism has rarely been studied. This study analyzed the relationship between the structural deformation of an aged separator and the electrochemical performance of LIBs. We discovered that even if the polyethylene (PE) separator is exposed to prolonged cycling under normal charging and discharging conditions, the by-products formed via electrolyte decomposition are firmly trapped in its pore, resulting in pore clogging. Additionally, the PE polymer chain gradually oxidizes at the part that is in contact with the cathode side, resulting in the loss of elasticity and breaking the polymer chain in the PE separator. These degradation processes of the PE separator can cause poor Li+ ion conductivity throughout the aged separator, which eventually results in lower electrochemical performance, particularly the rate performance, of LIBs.

데이트 폭력 인식과 폭력경험에 관한 연구

하예지(Ha, Yea ji),서미경(Seo, Mi kyung) 경성대학교 사회과학연구소 2014 社會科學硏究 Vol.30 No.4

본 연구는 데이트 폭력의 인식(심각성과 허용도)과 폭력 피해·가해경험과의 관련성을 분석하여 인식을 향상시키기 위한 실천적 대안을 제시하고자 수행되었다. 연구목적을 위해 20~30대 미혼남녀 858명을 대상으로 유형별 폭력(신체적 폭력, 심리적 폭력, 성적 폭력)을 묘사한 비네트 상황에 대한 심각성을 어떻게 인식하는지, 그러한 폭력이 질투, 무시, 선제공격으로 인한 폭력이었다면 허용할 수 있는지 그리고 모든 대상자의 심리, 신체, 성적 폭력의 피해, 가해경험을 질문하였다. 조사 결과 대상자의 인식수준을 보면, 각 비네트 상황에 대한 심각성은 5점 척도에 4.21로 높게 인식하였으나, 허용도 역시 4점 척도에 2.24로 높아, 심각하다고 인식하면서도 특정 상황에서는 데이트 폭력을 쉽게 허용할 수 있음을 알 수 있다. 각 유형별 폭력의 가해, 피해경험을 보면, 심리적 폭력은 대상자의 88%이상이 피해, 가해경험을 가지고 있었으며, 신체적 폭력은 가해경험 53.6%, 피해경험 49.5%였다. 성적 폭력은 가해경험이 28.1%, 피해경험이 30.7%였다. 인구통계학적 변인을 통제한 상태에서 데이트 폭력의 피해·가해경험과 인식과의 관련성을 보면, 성적 폭력의 피해·가해경험이 있는 경우 없는 경우보다 심각성은 낮게 인식하였고 상황별 허용도는 높았다. 신체적 폭력의 피해경험에서 심각성은 의미 있는 차이가 없었지만 상황별 허용도는 피해경험이 있는 경우 없는 경우보다 더 높았다. 그러나 신체적 폭력의 가해경험과 심리적 폭력의 피해·가해경험 유무에 따른 인식(심각성과 허용도)은 통계적으로 의미 있는 차이를 보이지 않았다. 결국 신체적 피해경험과 성적 폭력의 피해·가해경험이 있는 경우 인식수준이 더 낮아 폭력이 재발되어도 이를 허용할 가능성이 높으므로 인식을 향상시키기 위한 노력이 필요함을 제안하였다. The purpose of this study is to analyze the relationship between perception of dating violence and the offense and victimization violence experience(severity and acceptability). The participants were 858 unmarried men and women of 20s ~30s. We divided dating violence into psychological, physical, sexual of dating violence and has randomly presented one of the 3 types of vignettes to participants. The survey results on perception level of participants, severity of each vignette has been highly considered with 4.21 of 5 scale; however, in case of specific situation, it can be acceptability even though they"re perceive of seriousness likewise for acceptable with 2.24 of 4 scale. According to the offense and victimization experienced by each type of violence, In psychological violence, above 88% participants has offense and victimization. In physical violence, 53.6% participants has offense experience, 49.5% participants has victimization experience. In sexual violence, 28.1% participants has offense experience, 30.7% participants has victimization experience. According to the relation between offense, victimization experience and perception, When compared experienced group with no experienced group, the experienced group in physical and sexual violence is perceive of seriousness lowly but acceptability for each situation indicates high results. However, there is no significant difference in psychological violence. Finally, violence can be recurrent due to low perception level in case of having offense and victimization experience in physical, sexual violence. Accordingly, the endeavor is suggested to improve perception due to the fact that it has dangerousness into family violence.

의대생의 성격유형(MBTI)에 따른 블렌디드 해부학실습의 만족도와 학업성취도 연구

하예지 ( Yeji Ha ),김건호 ( Keonho Kim ),김동원 ( Dongwon Kim ),이경율 ( Kyungyul Lee ),임선주 ( Sunju Im ) 인문사회 21 2023 인문사회 21 Vol.14 No.1

연구 목적: 해부학 실습은 의학교육에 필수적이다. 연구진은 학생들의 마이어스-브릭스 유형 지표(MBTI)와 관련하여 블렌디드 해부학 실습의 만족도와 학업성취도에 대한 연구를 수행하였다. 연구 방법: 2021년 해부학을 수강한 의예과 107명을 대상으로 MBTI 성격유형, 해부학 실습만족도를 조사하였다. 계획과 안내, 사전학습(e-anatomy), 실습운영, 실습지도, 동료와의 협력, 실습평가, 자기평가 및 실습성과가 포함된 25개의 설문지를 리커트 척도로 개발하였다. 성격의 빈도, 만족도의 평균과 표준편차, 성격에 따른 만족도와 학업성취도의 차이를 조사하였다. 연구 내용: ISTJ 학생들이 18명(16.8%)으로 빈도가 가장 높았다. 만족도 실습성과(4.661)가 가장 높았고, 실습운영(3.393)이 가장 낮았다. 사전학습(e-anatomy)(0.042), 실습평가(0.032), 자기평가(0.052)는 외향형(E)과 내향형(I) 간에 유의한 차이를 보였다. 감각형(S)의 학업성취도는 직관형(N)보다 유의미하게 높았다. 결론 및 제언: 성격유형은 만족도와 학업성취도에 영향을 미친다. 따라서 의대는 각 성격유형의 특성을 고려하여 해부학 실습을 개선할 필요가 있다. Anatomy cadaver dissection practice is essential for Medical education. We conducted studies about satisfaction and academical achievements of blended anatomy cadaver practice related to students’ Myers-Briggs Type Indicator (MBTI). We took surveys including MBTI and satisfaction in anatomy cadaver practice to 107 second-year premedical students, who studied anatomy in 2021. We developed 25 questionnaires with Likert’s scale, which contain plannig and introduction, pre-learning (e-anatomy), practice operation, practice guidance, collaboration with colleagues, practice assessment, self-evaluation, and practice outcome. We investigated frequency of personality, mean and standard deviation of satisfaction, differences of satisfaction according to personality, differences of academic achievement according to personality. As a result, ISTJ personality was the most frequent (N=18, 16.8%). Highest mean score in the satisfaction was practice outcome (4.661), whereas lowest mean score was practice operation (3.393). Pre-learning (e-anatomy) (0.042), practice assessment (0.032), and self-evaluation (0.052) showed meaningful differences between personalities of extraversion and introversion. Academic achievement of sensing type students was meaningfully higher than intuition type students. In conclusion, personality types affect satisfaction and academic achievement. Therefore, medical schools need to improve anatomy cadaver practice in consideration of the characteristics of each personality type.

은나노와이어 기반 고효율/저비용 유연 전자 소자 패터닝 기술 개발

한예지(Yeji Han),최충현(Chunghyeon Choi),고성찬(Seongchan Ko),하희보(Hee-Bo Ha),서영재(Youngjae Seo),황병일(Byungil Hwang) 대한전자공학회 2020 대한전자공학회 학술대회 Vol.2020 No.8

Granulomatosis with polyangiitis initially manifested by fever and asymptomatic splenic involvement

최예지,강은하,이윤종,하유정 대한내과학회 2019 대한내과학회 추계학술대회 Vol.2019 No.1

지질다당류와 자성비드가 섞인 염색액으로 처리된 프리모관의 자기장 반응 특성 연구

이혜리,홍예지,하예은,김지영,노영일,노민석,강석윤,이상석 한국자기학회 2015 한국자기학회 학술연구발표회 논문개요집 Vol.2015 No.5

염증유발 지질다당류(LPS)와 자성비드가 주입된 토끼 프리모관의 자기장 영향 연구

이혜리,하예은,김지영,홍예지,김근호,강석윤,이상석 한국자기학회 2015 한국자기학회 학술연구발표회 논문개요집 Vol.2015 No.11

서울시 유해대기오염물질의 오염특성: 시계열 변화, 오염원 추정, 위해성평가

최성득,이승복,최예지,김성준,김창혁,이선엽,임형진,안예진,하현주,최유리,김진영 한국대기환경학회 2024 한국대기환경학회지 Vol.40 No.1

Hazardous air pollutants (HAPs) are primarily emitted from human activities in industrial and urban areas, and they have adverse impacts on human health. While many studies have focused on monitoring individual HAPs in Seoul, simultaneous measurements of various types of HAPs have been rare. In this study, therefore, volatile organic compounds (VOCs), carbonyl compounds, particle-bound polycyclic aromatic hydrocarbons (pPAHs), black carbon (BC), heavy metals, and criteria air pollutants (CAPs) were simultaneously measured at a site in Yangcheon-gu, Seoul, Korea. The concentrations of most VOCs were high in the fall and spring mainly due to low wind speeds. Conversely, several VOCs emitted from solvents in industrial and urban areas exhibited high concentrations in the summer. Benzene was positively correlated with BC and CO, and BC showed a positive correlation with CO and PM2.5. Additionally, pPAHs exhibited a positive correlation with BC and CO, suggesting an association with incomplete combustion. NO2 was negatively correlated with O3, formed by photochemical reactions in the atmosphere. The hourly concentration trends of NOx and SO2 coincided, potentially linked to emissions from non-industrial sources. Higher concentrations of benzene, BC, PM10, pPAHs, NO2, CO, and SO2 were observed during commute times. PM10 concentrations in the fall exceeded the daily national guideline of 100 μg/m3 due to long-range atmospheric transport from China. Despite their relatively low concentrations, acetaldehyde & ethylene oxide, acrylonitrile, and 1,3-butadiene posed significant cancer and non-cancer risks. The findings of this study highlight that the levels and patterns of HAPs in Seoul are mainly influenced by local sources (e.g., solvents, vehicular exhaust, and combustion) as well as longrange atmospheric transport, and their order of priority varies based on levels and associated risks.

The first Korean case with Floating-Harbor syndrome with a novel SRCAP mutation diagnosed by targeted exome sequencing

최은미,이동현,강석진,심예지,김흥식,김준식,정종인,하정숙,장자현 대한소아청소년과학회 2018 Clinical and Experimental Pediatrics (CEP) Vol.61 No.12

Floating-Harbor syndrome is a rare autosomal dominant genetic disorder associated with SRCAP muta tion. To date, approximately 50 cases of Floating-Harbor syndrome have been reported, but none have been reported in Korea yet. Floating-Harbor syndrome is characterized by delayed bony maturation, unique facial features, and language impairment. Here, we present a 6-year-old boy with a triangular face, deep-set protruding eyes, low-set ears, wide nose with narrow nasal bridge, short philtrum, long thin lips, clinodactyly, and developmental delay that was transferred to our pediatric clinic for genetic evaluation. He showed progressive delay in the area of language and cognition-adaption as he grew. He had previously undergone chromosomal analysis at another hospital due to his language delay, but his karyotype was normal. We performed targeted exome sequencing, considering several syndromes with similar pheno types. Library preparation was performed with the TruSight One sequencing panel, which enriches the sample for about 4,800 genes of clinical relevance. Massively parallel sequencing was conducted with NextSeq. An identified variant was confirmed by Sanger sequencing of the patient and his parents. Finally, the patient was confirmed as the first Korean case of Floating-Harbor syndrome with a novel SRCAP (Snf2 related CREBBP activator protein) mutation (c.7732dupT, p.Ser2578Phefs*6), resulting in early termination of the protein; it was not found in either of his healthy parents or a control population. To our knowledge, this is the first study to describe a boy with Floating-Harbor syndrome with a novel SRCAP mutation diagnosed by targeted exome sequencing in Korea.

반대쪽 팔 들기 동작 시 만성요통환자와 정상인의 다열근 두께 변화 비교

송원빈,김지혁,정웅근,하예지,한성구,황보인,Song, Won-bin,Kim, Chi-hyok,Jung, Woong-keun,Ha, Ye-ji,Han, Seong-gu,Hwangbo, In 대한정형도수물리치료학회 2018 대한정형도수물리치료학회지 Vol.24 No.2

Backdround: Using RUSI (Rehabilitation Ultra Sound Imiging) method, which showed high reliability in soft tissue measurements, we compared the muscle relax and contraction, sex, and physical characteristics of the activity of the multifidus muscle in patients with chronic low back pain and normal subjects. Methods: In this study, 16 patients (male: 8, female: 8) with chronic low back pain and 16 healthy adult (male: 8, female: 8) were participated. Subjects lied prone posture on the table with elbow flexed $90^{\circ}$ and shoulder abducted $120^{\circ}$ (starting position). Test was applied two types that muscle relax position and muscle contraction position. Muscle relax position is equal to starting position and muscle contraction position is that upper extremity lift up about 5cm from the table. We measured the thickness of the multifidus muscle in each position by ultrasound. Results: There was a statistically significant difference between the two groups in deviation of Both Side Difference of Activated resting-Arm Lifting Ratio according to posture change between the chronic low back pain patient group and the normal group. Conclusion: The result of this study support previous study showing that there is an imbalance in the activity of multifidus in patients with chronic low back pain.