The factors influencing happiness of college students

Yunjung, Oh 한국간호과학회 2023 한국간호과학회 학술대회 Vol.2023 No.11

Role of Anions in Aqueous Sol–Gel Process Enabling Flexible Cu(In,Ga)S₂ Thin-Film Solar Cells

Oh, Yunjung,Woo, Kyoohee,Lee, Daehee,Lee, Hongseuk,Kim, Kyujin,Kim, Inhyuk,Zhong, Zhaoyang,Jeong, Sunho,Moon, Jooho American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.20

<P>Recently, environmental-friendly, solution-processed, flexible Cu(In,Ga)(S,Se)<SUB>2</SUB> devices have gained significant interest, primarily because the solution deposition method enables large-scale and low-cost production of photovoltaics, and a flexible substrate can be implemented on uneven surfaces in various applications. Here, we suggest a novel green-chemistry aqueous ink that is readily achievable through the incorporation of molecular precursors in an aqueous medium. A copper formate precursor was introduced to lower the fabrication temperature, provide compatibility with a polyimide plastic substrate, and allow for high photovoltaic performance. Through a comparative spectroscopic study on temperature-dependent chemical/crystal structural evolution, the chemical role of copper formate was elucidated, which led to the chalcopyrite framework that was appropriate to low-temperature annealed Cu(In,Ga)S<SUB>2</SUB> absorber layers at 400 °C. This Cu(In,Ga)S<SUB>2</SUB> solar cell exhibited a power conversion efficiency of 7.04% on a rigid substrate and 5.60% on a polymeric substrate. Our cell on the polymeric substrate also demonstrated both acceptable mechanical flexibility and durability throughout a repeated bending test of 200 cycles.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-20/am504194t/production/images/medium/am-2014-04194t_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am504194t'>ACS Electronic Supporting Info</A></P>

Factors Influencing on Disaster Nursing Core Competencies in Nursing Students

Yunjung, Oh 한국간호과학회 2021 한국간호과학회 학술대회 Vol.2021 No.10

Aim(s) : The aim of this study was to identify the factors influencing on disaster nursing core competencies in nursing students by disaster perception, disaster attitudes and self-efficacy Method(s) : A descriptive correlation study design was used. A sample of convenience was 187 nursing students, and a questionnaire was used to measure their disaster perception, disaster attitudes, self-efficacy and disaster nursing core competencies. Data were collected from Novermber 30 to December 10, 2020 and analyzed with t-test, ANOVA, pearson"s correlation coefficient and stepwise multiple regression by using SPSS Program. Result(s) : The average mean disaster perception score was 3.66(±0.37), disaster attitude score was 3.56(±0.37) and self-efficacy score was 3.67(±0.49). The disaster nursing core competencies score ranged from 31 to 63, and the average mean score was 3.15(±0.40). Disaster nursing core competencies were significantly different according to grade and satisfaction with clinical practice. Disaster nursing core competencies were positively correlated with disaster perception, disaster attitudes and self-efficacy. The influencing factors in disaster nursing core competencies were self-efficacy (β=0.276, p<.001), disaster attitudes (β=0.200, p=.003) and grade (β=0.172, p=.011). The explanatory power of these variables was 19.1%(F=14.378, p<.001). Conclusion(s) : Based on the results, the most important factor in disaster nursing core competencies was self-efficacy. Therefore, it is necessary to develop a disaster program that can improve the disaster nursing core competencies of nursing students based on the factors influencing the disaster nursing core competencies.

The Factors Influencing experience of good class of nursing students

Yunjung, Oh,Hyang Dong, Kim 한국간호과학회 2023 한국간호과학회 학술대회 Vol.2023 No.11

Photoelectrodes based on 2D opals assembled from Cu-delafossite double-shelled microspheres for an enhanced photoelectrochemical response

Oh, Yunjung,Yang, Wooseok,Tan, Jeiwan,Lee, Hyungsoo,Park, Jaemin,Moon, Jooho The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.8

<P>Although a unique light-harvesting property was recently demonstrated in a photocathode based on 2-dimensional (2D) opals of CuFeO2-shelled SiO2 microspheres, the performance of a monolayer of ultra-thin CuFeO2-shelled microspheres is limited by ineffective charge separation. Herein, we propose an innovative design rule, in which an inner CuFeO2/outer CuAlO2 double-shelled heterojunction is formed on each partially etched microsphere to obtain a hexagonally assembled 2D opal photoelectrode. Our Cu-delafossite double-shelled photocathode shows a dramatically improved charge separation capability, with a 9-fold increase in the photocurrent compared to that of the single-shelled counterpart. Electrochemical impedance spectroscopy clearly confirms the reduced charge transport/transfer resistance associated with the Cu-delafossite double-shelled photocathode, while surface photovoltage spectra reveal enhanced polarization of the photogenerated carrier, indicating improved charge separation capability with the aid of the heterojunction. Our finding sheds light on the importance of heterojunction interfaces in achieving optimal charge separation in opal architectures as well as the inner-shell/electrolyte interface to expedite charge separation/transport.</P>

Physical Health and Mental Health Status of Female College Students according to Perceived Smartphone Addiction

Oh, Yunjung,Kim, Hyangdong 한국간호과학회 2019 한국간호과학회 학술대회 Vol.2019 No.10

CO₂ emissions correction of light-duty vehicles based on an energy deviation analysis method

Oh, Yunjung,Kwon, Sang Il,Park, Sungwook Pergamon 2017 Transportation Research Part D. Transport & Enviro Vol.56 No.-

<P><B>Abstract</B></P> <P>In present study, a total of 3 types of light-duty vehicles were tested for 7 types of driving modes by using a vehicle dynamics-based simulation method. Deviations between the target and actual test vehicle speed and inaccurate chassis dynamometer road load settings are selected as the two main factors affecting the CO<SUB>2</SUB> emission measurement test. 126 cases of simulations were conducted to analyze the effects of the deviation between the target and actual test vehicle speed on CO<SUB>2</SUB> emissions and 63 cases of simulation were conducted to analyze the effectiveness of inaccurate road load test conditions on CO<SUB>2</SUB> emissions. Then, the CO<SUB>2</SUB> correlation method proposed by World Forum for Harmonization of Vehicle Regulations (WP.29, UN) was applied for simulated results in original simulation cases, and a correction to performance was validated by comparative analysis. From the simulation results, it is revealed that velocity and road load deviation are related to distinct changes in fuel efficiency and CO<SUB>2</SUB> emission rates of test vehicles. Also, it is revealed that CO<SUB>2</SUB> correction method show good performance to reduce the relative error lower than 2% in all test cases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3 types of light-duty vehicles were investigated by using a vehicle dynamics-based simulation method. </LI> <LI> Chassis dynamo test result was affected by deviation against target speed and inaccurate road load condition. </LI> <LI> The CO<SUB>2</SUB> correlation method based on total work deviation was applied to reduce a relative error. </LI> <LI> When applying the correction method, the relative error of CO<SUB>2</SUB> emission converged within 2% in all cases. </LI> <LI> CO<SUB>2</SUB> correction method will be a good solution to advance reliability of chassis dynamometer test results. </LI> </UL> </P>

Aqueous Solution-Phase Selenized CuIn(S,Se)₂ Thin Film Solar Cells Annealed under Inert Atmosphere

Oh, Yunjung,Yang, Wooseok,Kim, Jimin,Woo, Kyoohee,Moon, Jooho American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.40

<P>A nonvacuum solution-based approach can potentially be used to realize low cost, roll-to-roll fabrication of chalcopyrite CuIn(S,Se)<SUB>2</SUB> (CISSe) thin film solar cells. However, most solution-based fabrication methods involve highly toxic solvents and inevitably require sulfurization and/or postselenization with hazardous H<SUB>2</SUB>S/H<SUB>2</SUB>Se gases. Herein, we introduce novel aqueous-based Cu–In–S and Se inks that contain an amine additive for producing a high-quality absorber layer. CISSe films were fabricated by simple deposition of Cu–In–S ink and Se ink followed by annealing under an inert atmosphere. Compositional and phase analyses confirmed that our simple aqueous ink-based method facilitated in-site selenization of the CIS layer. In addition, we investigated the molecular structures of our aqueous inks to determine how crystalline chalcopyrite absorber layers developed without sulfurization and/or postselenization. CISSe thin film solar cells annealed at 550 °C exhibited an efficiency of 4.55% under AM 1.5 illumination. The low-cost, nonvacuum method to deposit chalcopyrite absorber layers described here allows for safe and simple processing of thin film solar cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-40/acsami.5b06996/production/images/medium/am-2015-06996t_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b06996'>ACS Electronic Supporting Info</A></P>

Enhanced Photocurrent of Transparent CuFeO₂ Photocathodes by Self-Light-Harvesting Architecture

Oh, Yunjung,Yang, Wooseok,Kim, Jimin,Jeong, Sunho,Moon, Jooho American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.16

<P>Efficient sunlight-driven water-splitting devices can be achieved by using an optically and energetically well-matched pair of photoelectrodes in a tandem configuration. The key for maximizing the photoelectrochemical efficiency is the use of a highly transparent front photoelectrode with a band gap below 2.0 eV. Herein, we propose two-dimensional (2D) photonic crystal (PC) structures consisting of a CuFeO2-decorated microsphere monolayer, which serve as self-light-harvesting architectures allowing for amplified light absorption and high transparency. The photocurrent densities are evaluated for three CuFeO2 2D PC-based photoelectrodes with microspheres of different sizes. The optical analysis confirmed the presence of a photonic stop band that generates slow light and at the same time amplifies the absorption of light. The 410 nm sized CuFeO2 decorated microsphere 21) PC photocathode shows an exceptionally high visible light transmittance of 76.4% and a relatively high photocurrent of 0.2 mA cm(-2) at 0.6 V vs a reversible hydrogen electrode. The effect of the microsphere size on the carrier collection efficiency was analyzed by in situ conductive atomic force microscopy observation under illumination. Our novel synthetic method to produce self-light-harvesting nanostructures provides a promising approach for the solar energy by highly transparent photocathodes. effective use of solar energy by highly transparent photocathodes.</P>

차대동력계 시험에서 발생하는 일량 편차가 연비 및 CO₂ 배기에 미치는 영향에 대한 수치적 연구

오윤중(Yunjung Oh),권상일(Sang Il Kwon),엄명도(Myung Do Eom),박성욱(Sungwook Park) 한국자동차공학회 2015 한국자동차공학회 부문종합 학술대회 Vol.2015 No.5