Highly transparent and conductive oxide-metal-oxide electrodes optimized at the percolation thickness of AgO_x for transparent silicon thin-film solar cells

Jo, Hyunjin,Yang, Jo-Hwa,Choi, Soo-Won,Park, Jaeho,Song, Eun Jin,Shin, Myunhun,Ahn, Ji-Hoon,Kwon, Jung-Dae Elsevier 2019 Solar energy materials and solar cells Vol.202 No.-

<P><B>Abstract</B></P> <P>Highly transparent and conductive oxide-metal-oxide (OMO) electrodes comprising aluminum-doped zinc-oxide (AZO) and ultrathin Ag or oxygen (O<SUB>2</SUB>)-doped Ag (AgO<SUB>x</SUB>) metal layers were fabricated for use in thin-film silicon solar cells. The surface morphologies of the metal layers and the transparencies and conductivities of OMO electrodes were investigated near the percolation thickness values of the metal layers. The percolation metal thickness, which means the metal layer is morphologically continuous, could be used to optimize the transparent OMO electrode. Additionally, thin Ag-based OMO (AgO<SUB>x</SUB> OMO) with superior performance could be fabricated by adding O<SUB>2</SUB>. The optimized AgO<SUB>x</SUB> OMO electrodes yielded the highest average transmittance (<I>T</I> <SUB>avg</SUB>) of 93.5% and the lowest average optical loss (OL<SUB>avg</SUB>) of 1.01% within 500–800 nm at the percolation thickness of ~6 nm, thus, maintaining low conductivity. These outcomes were superior to the responses of the percolated Ag OMO (<I>T</I> <SUB>avg</SUB> = 87.2%; OL<SUB>avg</SUB> = 1.01%). Using the OMO structure at the rear electrode, transparent hydrogenated amorphous silicon thin-film solar was fabricated for building integrated photovoltaic windows. The best figure-of-merit (FOM; equal to the product of <I>T</I> <SUB>avg</SUB> and efficiency <I>η</I>) values of the OMO-based transparent solar cells could be obtained for percolated OMO structures. The cells using AgO<SUB>x</SUB> OMO (AgO<SUB>x</SUB> cells) performed better than the Ag cells; the best FOMs of AgO<SUB>x</SUB> and Ag cells were 140.8 (<I>T</I> <SUB>avg</SUB> = 27.8%; <I>η</I> = 5.51%) and 104.6% (<I>T</I> <SUB>avg</SUB> = 18.9%; <I>η</I> = 5.54%), respectively. These results could contribute to the development of high-performance transparent solar cells or optoelectronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Transparent/conductive oxide-metal-oxide (OMO) electrodes were fabricated. </LI> <LI> Oxygen doping effects in thin Ag film is investigated. </LI> <LI> Optimization of OMO electrodes was based on the percolation metal thickness. </LI> <LI> Thin oxygen-doped Ag-based OMO electrodes yielded better performances. </LI> <LI> Optimized electrodes can be used in high-performance transparent solar cells/devices. </LI> </UL> </P>

A Survival Analysis of Employment Instability in the Korean Labor Market

Hyunjin Jo,GiSeung Kim 한국응용경제학회 2015 응용경제 Vol.17 No.4

본 연구는 1~13차 한국노동패널데이터(KLIPS)를 사용하여 국내 노동시장의 고용불안 정도를 분석하고, 사회경제적 요인 및 인적요인들이 고용불안에 미치는 영향을 cox-proportional hazard regression을 이용하여 찾고자 하였다. 분석 결과 국내 임금직 노동자의 고용불안정에 영향을 미치는 요인은 연령, 교육수준 등의 인적특성과 노조, 종사상 지위 등의 노동시장특성에 다양하게 나타났으며 각 요인들이 영향을 미치는 정도는 각기 다르게 나타났다. 교육수준이 높을수록, 정규직일수록 노동시장에서의 생존율이 높게 나타났으며 나이가 어리고 교육정도가 낮으며 비정규직이며 비노조원일수록 실직위험률이 높으며 이에 따라 노동시장에서의 안정성이 떨어지는 것으로 분석된다. This study uses Korea Labor and Income Panel data (KLIPS) of 13-year period and analyze the employment instability of the domestic labor market and find socio-economic factors and human factors which effects job insecurity using the cox-proportional hazard regression. The factors affecting the employment instability of domestic workers varies in human characteristics and labor market characteristics such as age, education years, labor union or employment status. The effect scale also varies. The survival rate is higher if workers have higher education level and regular job. If workers are included in certain category of young, non-labor union member, lower education level or irregular job, unemployment risk is higher and as a result, the stability in labor market is by falling.

Effects of Organic Light-Emitting Diodes on Circadian Rhythm and Sleep

Jo Hyunjin,Park Hea Ree,Choi Su Jung,Lee Soo-Youn,Kim Seog Ju,Joo Eun Yeon 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.5

Objective Organic light-emitting diodes (OLEDs) emit less blue light than traditional light-emitting diodes (LEDs), and we previously found that early-night OLED light exposure (LE) delays the melatonin phase by less than LED at a color temperature of 4,000 K. As a follow-up study, we investigated the effects of OLED and LED at a different color temperature (3,000 K) on melatonin profile, sleep, and vigilance.Methods 24 healthy subjects (27.5±5.1 years) were exposed to three light conditions [OLED, LED, and dim light (DL)] from 17:30 to 24:00, in a random order and with a 1-week interval. Saliva samples for melatonin were taken every hour from 18:00 to 24:00. Polysomnography (PSG) and a psychomotor vigilance test (PVT) were performed.Results Melatonin onset time was significantly delayed under OLED and LED compared with DL, with no significant difference between OLED and LED. The mean melatonin level at 24:00 under LED was lower than that under DL, but there was no significant difference between OLED LE and DL. The percentage of slow wave sleep (N3) in LED was significantly lower than in OLED.Conclusion Exposure to light in the evening can suppress melatonin secretion late at night and disturb deep sleep, and those effects are slightly worse under LED than OLED.

New approach of using cortico-cortical evoked potential for functional brain evaluation

Hyunjin Jo,Dongyeop Kim,Jooyeon Song,Dae-Won Seo 대한임상신경생리학회 2021 Annals of Clinical Neurophysiology Vol.23 No.2

Cortico-cortical evoked potential (CCEP) mapping is a rapidly developing method for visualizing the brain network and estimating cortical excitability. The CCEP comprises the early N1 component the occurs at 10-30 ms poststimulation, indicating anatomic connectivity, and the late N2 component that appears at < 200 ms poststimulation, suggesting long-lasting effective connectivity. A later component at 200-1,000 ms poststimulation can also appear as a delayed response in some studied areas. Such delayed responses occur in areas with changed excitability, such as an epileptogenic zone. CCEP mapping has been used to examine the brain connections causally in functional systems such as the language, auditory, and visual systems as well as in anatomic regions including the frontoparietal neocortices and hippocampal limbic areas. Task-based CCEPs can be used to measure behavior. In addition to evaluations of the brain connectome, single-pulse electrical stimulation (SPES) can reflect cortical excitability, and so it could be used to predict a seizure onset zone. CCEP brain mapping and SPES investigations could be applied both extraoperatively and intraoperatively. These underused electrophysiologic tools in basic and clinical neuroscience might be powerful methods for providing insight into measures of brain connectivity and dynamics. Analyses of CCEPs might enable us to identify causal relationships between brain areas during cortical processing, and to develop a new paradigm of effective therapeutic neuromodulation in the future.

Effect of Cnidium japonicum Miq. Crude Extract Against Ultraviolet A-induced Photoaging in Human Dermal Fibroblasts

HyunJin JO,JungHwan OH,Fatih KARADENIZ,HyeRan KIM,SoYoung PARK,Youngwan SEO,Chang-Suk KONG 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.4

Transparent bifacial a-Si:H solar cells employing silver oxide embedded transparent rear electrodes for improved transparency

Jo, Hyunjin,Yang, Jo-Hwa,Lee, Ji-hoon,Lim, Jung-Wook,Lee, Jaesung,Shin, Myunhun,Ahn, Ji-Hoon,Kwon, Jung-Dae Elsevier 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.170 No.-

<P><B>Abstract</B></P> <P>We developed a transparent oxide–metal–oxide (OMO) structure using aluminum-doped zinc oxide and oxidized silver (AgO<SUB>x</SUB>) as a transparent electrode of a hydrogenated amorphous silicon (a-Si:H) thin-film solar cell for use in building-integrated photovoltaic (BIPV) windows. The oxygen (O<SUB>2</SUB>) addition (O<SUB>2</SUB> flow rate) was optimized for a metal-to-dielectric intermediate-phase AgO<SUB>x</SUB> OMO to have high transparency and high conductivity, which were confirmed by finite-difference time-domain simulation. Using the AgO<SUB>x</SUB> OMO as a rear electrode, transparent a-Si:H solar cells were fabricated for BIPV window application. The performance of the fabricated cells showed highest bifacial efficiency (b-<I>η</I>) of 7.87% at AgO<SUB>x</SUB> OMO of 1 sccm, and highest average transmittance (<I>T</I> <SUB>500–800</SUB>, i.e., wavelength range: 500–800 nm) of 21.9% at AgO<SUB>x</SUB> OMO of 3 sccm, i.e., improvements from b-<I>η</I> = 7.42% and <I>T</I> <SUB>500–800</SUB> = 18.8% at Ag OMO of 0 sccm. The cell with the optimized AgO<SUB>x</SUB> OMO (3 sccm) achieved b-<I>η</I> = 7.69% and the best figure of merit (product of b-<I>η</I> and <I>T</I> <SUB>500–800</SUB>) of 169%, i.e., 30% higher than the Ag OMO cell (139%). The developed AgO<SUB>x</SUB> OMO electrodes could be used in BIPV windows or in other optical devices requiring both high transparency and high conductivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AgO<SUB>x</SUB> is introduced in a transparent oxide-metal-oxide (OMO) structure. </LI> <LI> Oxidization of AgO<SUB>x</SUB> is optimized for high transparency and efficiency of transparent a-Si:H solar cells. </LI> <LI> Optical property of AgO<SUB>x</SUB>-OMO is investigated experimentally and theoretically. </LI> <LI> Bifacial operation property of a-Si:H solar cells was presented. </LI> </UL> </P>

COVID-19 상황에서 간호대학생의 MBTI 성격유형, 학습전략, 사회적지지가 학업스트레스에 미치는 영향

조미래(Jo, Mirae),이현진(Lee, Hyunjin),신유진(Shin, Yujin),김수현(Kim Soo-hyun),김서영(Kim Seo-young),조금주(Jo, Geum-joo),장수현(Jang Soo-hyun) 학습자중심교과교육학회 2022 학습자중심교과교육연구 Vol.22 No.7

Objectives This study is a descriptive survey designed to identify the effects of MBTI personality type, learning strategy, and social support on academic stress in nursing students under untact educational environment caused by COVID-19. Methods The subjects of this study are 125 nursing students who were 1-4 graders attending one university located in D metropolitan city. Data were collected from Oct. 5, 2021 to Nov. 18, 2021. For data analysis, SPSS 23.0 program was used for descriptive statistics, t-test, ANOVA, pearson’s correlation, and hierarchical regression. Results In non-face-to-face class environment caused by COVID-19, nursing students’ academic stress had a negative correlation with learning strategy and social support and their learning strategy had a positive correlation with social support. As a result of regression analysis, it was found that gender, major satisfaction, learning strategy, and social support affected academic stress and these variables accounted for 31.6% of academic stress. Conclusions To reduce academic stress in the COVID-19 situation, there is a need to develop programs for improving major satisfaction, learning strategy, and social support and seek various solutions. 목적 COVID-19 상황에서 간호대학생의 MBTI 성격유형, 학습전략, 사회적지지가 학업스트레스에 미치는 영향을 파악하고자 실시된 서술적 조사연구이다. 방법 대상자는 D광역시 소재 1개 대학교에 재학 중인 1~4학년 간호대학생 125명이다. 자료수집 기간은 2021년 10월 5일부터 11월 18일까지이며, 구글 설문지를 활용한 온라인 설문 방식을 사용하여 자료를 수집하였다. 자료분석은 SPSS 23.0 프로그램을 활용하여 서술통계, T-test, ANOVA, Pearson’s correlation, Hierarchical regression이 실시되었다. 결과 COVID-19 상황에서 간호대학생의 학업스트레스는 학습전략과, 사회적지지와 부적 상관관계가 있었고 학습전략은 사회적지지와 정적 상관관계를 나타냈다. 또한 회귀분석 결과, 성별, 전공만족도, 학습전략, 사회적지지가 학업스트레스에 영향을 미치는 변수로 나타났으며, 이 변수들은 학업스트레스를 31.6% 설명하였다. 결론 COVID-19 상황에서 학업스트레스 감소를 위해서는 전공만족도, 학습전략, 사회적지지 향상을 위한 프로그램 개발 및 다양한 방안을 모색해야 한다.

Impact of COVID-19 Infection and Its Association With Previous Vaccination in Patients With Myasthenia Gravis in Korea: A Multicenter Retrospective Study

Han Hee Jo,Kim Seung Woo,Kim Hyunjin,So Jungmin,Lee Eun-Jae,Lim Young-Min,Lee Jung Hwan,Lee Myung Ah,Kim Byung-Jo,Baek Seol-Hee,Lee Hyung-Soo,Sohn Eunhee,Kim Sooyoung,Park Jin-Sung,Kang Minsung,Park H 대한의학회 2024 Journal of Korean medical science Vol.39 No.18

Background: During the coronavirus disease 2019 (COVID-19) pandemic, patients with myasthenia gravis (MG) were more susceptible to poor outcomes owing to respiratory muscle weakness and immunotherapy. Several studies conducted in the early stages of the COVID-19 pandemic reported higher mortality in patients with MG compared to the general population. This study aimed to investigate the clinical course and prognosis of COVID-19 in patients with MG and to compare these parameters between vaccinated and unvaccinated patients in South Korea. Methods: This multicenter, retrospective study, which was conducted at 14 tertiary hospitals in South Korea, reviewed the medical records and identified MG patients who contracted COVID-19 between February 2022 and April 2022. The demographic and clinical characteristics associated with MG and vaccination status were collected. The clinical outcomes of COVID-19 infection and MG were investigated and compared between the vaccinated and unvaccinated patients. Results: Ninety-two patients with MG contracted COVID-19 during the study. Nine (9.8%) patients required hospitalization, 4 (4.3%) of whom were admitted to the intensive care unit. Seventy-five of 92 patients were vaccinated before contracting COVID-19 infection, and 17 were not. During the COVID-19 infection, 6 of 17 (35.3%) unvaccinated patients were hospitalized, whereas 3 of 75 (4.0%) vaccinated patients were hospitalized (P < 0.001). The frequencies of ICU admission and mechanical ventilation were significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.019 and P = 0.032, respectively). The rate of MG deterioration was significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.041). Logistic regression after weighting revealed that the risk of hospitalization and MG deterioration after COVID-19 infection was significantly lower in the vaccinated patients than in the unvaccinated patients. Conclusion: This study suggests that the clinical course and prognosis of patients with MG who contracted COVID-19 during the dominance of the omicron variant of COVID-19 may be milder than those at the early phase of the COVID-19 pandemic when vaccination was unavailable. Vaccination may reduce the morbidity of COVID-19 in patients with MG and effectively prevent MG deterioration induced by COVID-19 infection.

A CPW-Fed Rectangular Ring Monopole Antenna for WLAN Applications

Jo, Sangjin,Choi, Hyunjin,Shin, Beomsoo,Oh, Sangyeol,Lee, Jaehoon Hindawi Limited 2014 International journal of antennas and propagation Vol.2014 No.-

<P>We present a simple coplanar waveguide- (CPW-) fed rectangular ring monopole antenna designed for dual-band wireless local area network (WLAN) applications. The antenna is based on a simple structure composed of a CPW feed line and a rectangular ring. Dual-band WLAN operation can be achieved by controlling the distance between the rectangular ring and the ground plane of the CPW feed line, as well as the horizontal vertical lengths of the rectangular ring. Simulated and measured data show that the antenna has a compact size of21.4×59.4 mm<SUP>2</SUP>, an impedance bandwidths of 2.21–2.70 GHz and 5.04–6.03 GHz, and a reflection coefficient of less than −10 dB. The antenna also exhibits an almost omnidirectional radiation pattern. This simple compact antenna with favorable frequency characteristics therefore is attractive for applications in dual-band WLAN.</P>

Fat deposition in the tunica muscularis and decrease of interstitial cells of Cajal and nNOS-positive neuronal cells in the aged rat colon

Jo, Hyun Jin,Kim, Nayoung,Nam, Ryoung Hee,Kang, Jung Mook,Kim, Joo-Hyon,Choe, Gheeyoung,Lee, Hye Seung,Park, Ji Hyun,Chang, Hyun,Kim, Hyunjin,Lee, Moon Young,Kim, Yong Sung,Kim, Joo Sung,Jung, Hyun Ch American Physiological Society 2014 American journal of physiology, Gastrointestinal a Vol.306 No.8

<P>Little is known about the time course of aging on interstitial cells of Cajal (ICC) of colon. The aim of this study was to investigate the change of morphology, ICC, and neuronal nitric oxide synthase (nNOS)-immunoreactive cells in the aged rat. The proximal colon of 344 Fischer rats at four different ages (6, 31, 74 wk, and 2 yr) were studied. The immunoreactivity of c-Kit, nNOS, anti-protein gene product 9.5, and synaptophysin were counted after immunohistochemistry. The <I>c-kit</I>, <I>stem cell factor</I> (ligand of Kit), and <I>nNOS</I> mRNA were measured by real-time PCR. c-Kit and nNOS protein were assessed by Western blot. Isovolumetric contractile force measurement and electrical field stimulation (EFS) were conducted. The area of intramuscular fat deposition significantly increased with age after 31 wk. c-Kit-immunoreactive ICC and nNOS-immunoreactive neurons and nerve fibers significantly declined with age. mRNA and protein expression of c-kit and nNOS decreased with aging. The functional study showed that the spontaneous contractility was decreased in aged rat, whereas EFS responses in the presence of atropine and <SMALL>l</SMALL>-NG-Nitroarginine methyl ester were increased in aged rat. In conclusion, the decrease of proportion of proper smooth muscle, the density of ICC and nNOS-immunoreactive neuronal fibers, and the number of nNOS-immunoreactive neurons during the aging process may explain the aging-associated colonic dysmotility.</P>