• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.2
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• pp.115-120
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• 2021

In this study, composite transparent electrodes were fabricated either from a conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) or silver nanowire (AgNW). Three transparent electrodes such as PEDOT:PSS, PEDOT:PSS and AgNW mixture, and AgNW were fabricated. As for a transparent electrode, measured sheet resistance values were 89.6, 60.6 and 28.6 Ω/sq, and the transmittance values were 80.2, 82.0 and 83.8% while surface roughness (Rq) values were 4.1, 8.1, 20.4 nm for PEDOT:PSS, PEDOT:PSS and AgNW mixture, and AgNW, respectively. To verify the overall performance of these composite electrodes, we applied these electrodes to the top electrode of the solution-processed organic solar cells (OSCs). PEDOT:PSS provided the best performance with a fill factor (FF) of 51.2% and a photoconversion efficiency (PCE) of 2.2%, while traditional metal top electrode OSC provided FF of 60.5% and PCE of 3.1%.

• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.364-368
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• 2021

We developed a highly efficient organic photovoltaic (OPV) cell with a poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)]:[6,6]-phenyl-C71-butyric acid methyl ester active layer for harvesting lower-intensity indoor light energy to power various self-powered sensor systems that require power in the microwatt range. In order to achieve higher power conversion efficiency (PCE), we first optimized the thickness of the active layer of the OPV cell through optical simulations. Next, we fabricated an OPV cell with optimized active layer thickness. The device exhibited a PCE of 12.23%, open circuit voltage of 0.66 V, short-circuit current density of 97.7 ㎂/cm², and fill factor of 60.53%. Furthermore, the device showed a maximum power density of 45 ㎼/cm², which is suitable for powering a low-power (microwatt range) sensor system.

• Current Photovoltaic Research
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• v.9 no.4
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• pp.123-127
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• 2021

This study was on electrode design for the realization of a solar cell that combines electrode formation and module integration process to overcome printing limitations. We used the passivated emitter rear contact (PERC) solar cell. Wafer size was 156.75 mm ×156.75 mm. The fabricated cell results showed that the open-circuit voltage of 649 mV, short-circuit current density of 36.15 mA/cm², fill factor of 68.5%, and efficiency of 16.06% with electrode conditions the 24BBs with the width 190 ㎛ and 90FBs with the width 45 ㎛. For improving efficiency, the characteristics of the solar cell were checked according to the change in the number of BBs and FBs and the change in line fine width. It is confirmed that the efficiency of the solar cell will be improved by increasing the number of FBs from 90 to 120, and increasing the line width of the FBs by about 10 ㎛ compared to the manufacturing solar cells.

• Journal of Korean society of Dental Hygiene
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• v.22 no.5
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• pp.393-400
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• 2022

Objectives: This study analyzes professional identity, resilience, and job satisfaction based on the personality types of dental hygienists, and identifies factors that impact job satisfaction. The aim was to provide basic information for developing customized education programs for each personality type, which consequently contribute toward improvement of job satisfaction in dental hygienists. Methods: A total of 215 dental hygienists working at dental hospitals and clinics in the Seoul and Gyeonggi provinces were ask to fill an online survey from June 20 to 30, 2022; of these, 214 surveys were considered for statistical analysis. Results: The professional identity of dental hygienists was correlated with resilience (r=0.750) and job satisfaction (r=0.452), and resilience was correlated with job satisfaction (r=0.539) (p<0.001). The factor affecting job satisfaction of dental hygienists was resilience (β=0.495) (p<0.001). Conclusions: In order to improve the job satisfaction of dental hygienists, it is necessary to implement a test that can identify individual characteristics. Accordingly, it will be necessary to develop a customized education program to improve professional identity and resilience.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.1
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• pp.409-434
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• 2023

A small library can be used as a place of cultural communication and educational experience for members of the local community that can fill the gaps of public libraries. In this study, the motives of users of small libraries were investigated. Semi-structured interviews were conducted with 45 users of small libraries, and their perceptions from their experiences were classified into four categories, 'attention', 'relevance', 'confidence', and 'satisfaction', and each factor was investigated. Small libraries showed that effective analysis, management, and design of factors related to the four motive classifications could further improve the opportunities of local community residents to find small libraries.

• The Journal of Industrial Distribution & Business
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• v.14 no.5
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• pp.19-29
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• 2023

Purpose: The hospitality sector is vital to economic development, especially in metropolitan regions, where hotels are a pivotal factor in drawing in leisure and corporate visitors. Despite the potential advantages of urban hotels, there is a gap in empirical studies on the impacts of eco-friendly interior design on hotel appeal and guest behavior. Therefore, this study aims to fill out the research gap. Research design, data and methodology: This study employed a review of the literature systematically as its research design. The study's data collection technique involves exploring peer-reviewed journals through electronic databases like Scopus, and Web of Science. The present author double-checked the quality of instrument for all usable dataset. Results: Prior literature has stated a strong linkage between green interior design in urban hotels and customer behavior and hotel attractiveness. Using environmentally conscious methods, hotels can enhance the quality of their indoor atmosphere, preserve energy and water supplies, and establish a favorable public perception that appeals to environmentally aware consumers, thereby improving their overall experience and contentment. Conclusions: This study concludes that creating indoor spaces with environmental factors in mind could lead to a more enjoyable and beneficial atmosphere for hotel visitors and adopting a sustainability-oriented approach to hotel design and operations could attract potential customers.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.94-97
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• 2022

We fabricated 3 types of ETL, mp TiO₂, ZnO, and ZnO coated on mp TiO₂(ZMT) to compare the photoelectric conversion efficiency (PCE) and fill factor (FF) of Perovskite solar cells. The structure of the cells was FTO/ETL/Perovskite (CH₃NH₃PbI₃)/spiro-MeOTAD/Ag. SEM morphology assessment of the ETLs showed that mp TiO₂ was porous, ZnO was flat, and the ZMT porous surface was filled with a thin layer. Via XRD measurements, the crystal structures of mp TiO₂ and ZnO ETL were found to be anatase and wurtzite, respectively. The XPS patterns showing energy bonding of mp TiO₂, ZnO, and ZMT O 1s confirmed these materials to be metal oxides such as ETL. The electrical characteristics of the Perovskite solar cells were measured using a solar simulator. Perovskite solar cells with ZMT ETL showed showed PCE of 10.29 % than that of conventional mp TiO₂ ETL devices. This was considered a result of preventing Perovskite from seeping into the ETL and preventing recombination of electrons and holes.

• Korean Journal of Materials Research
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• v.33 no.6
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• pp.236-241
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• 2023

Solar cells based on p-conjugated donor-acceptor (D-A) organic molecular systems are a promising alternative to conventional electrical energy generation. D-A molecular systems, which have a triphenylamine (TPA) moiety linked with a benzothiadiazole (BTD) moiety, open the potential development of new small molecule donors for bulk heterojunction (BHJ) solar cells. Here, a series of donor-acceptor-π-acceptor (D-A-π-A) small molecule donors (SMD) derived from triphenylamine (TPA) donor and benzothiadiazole (BTD) acceptor building blocks, were designed for BHJ organic solar cells. The small molecule donors SMD1-4 were studied using density functional theory (DFT) and time dependent-DFT (TDDFT) methods, to understand the effect of cyano and fluorine group functionalization on their properties. The effect of structure alteration by cyano and fluorine group functionalization on the optoelectronic properties, the calculated highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) and the HOMO-LUMO gaps were theoretically explored. The V_oc (open-circuit photovoltage) and fill factor (FF) for SMD1-4 were obtained with a PC₇₁BM acceptor, which showed that these organic small molecules are potential small molecule donors for organic bulk heterojunction solar cells.

• Journal of Korea Water Resources Association
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• v.48 no.4
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• pp.269-279
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• 2015

Nowadays, the world has suffered by natural disaster of climate change due to global warming. Korea has also faced with similar situation. To prevent these natural disaster, Four Major River Management has conducted. One of conducted content in Four Major River Management is the levee maintenance which classified into fill-up the inland, levee of reinforcement and so on. These maintenances may make the characteristics of groundwater flow change and affect to the levee safety (piping phenomenon). Therefore, analysis on groundwater fluctuation according to level of riverside and inland should be required. This study focus on levee of Hoe stream, which is connected to Nakdong river, and piping safety factor in the levee analyzed by using pore water pressure. Besides, groundwater fluctuation, which is depended on level of riverside and inland, is simulated by using the SEEP/W (2D ground water model). This simulation considered steady flow and unsteady flow. As a result, piping safety factor increased due to rising the inland level. Piping safety factor of riverside was effected by only river water level. Therefore, external levee factor considering inland level raising and suitable control of river water level is need to increase piping safety factor.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.22 no.3
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• pp.169-181
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• 2011

Objectives: The Child Report of Post-traumatic Symptoms (CROPS) and the Parent Report of Post-traumatic Symptoms (PROPS) are screening measures for post-traumatic symptoms in children. The present study aimed to investigate the reliability and validity of the Korean versions of the CROPS and the PROPS. Methods: The Korean versions of the CROPS and the PROPS were administered to a sample of 304 children aged 6 to 15 years old. The internal reliability, test-retest reliability, factorial validity, predictive validity and concurrent validity were evaluated. Results: The reliability of the CROPS and the PROPS was shown to have excellent internal consistency and test-retest correlation. The single factor structure of the PROPS was good and that of the CROPS was borderline acceptable according to confirmatory factor analysis. Other validity measures such as the predictive validity and concurrent validity were also shown to be satisfactory. Conclusion: This study demonstrated that the Korean versions of the CROPS and the PROPS were reliable measures with satisfactory psychometric qualities. Because it takes less than 5 minutes to fill out the CROPS and the PROPS, respectively they can be quick and easy screening scales for assessing post-traumatic symptoms in Korean children.