• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.512-518
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• 2019

To develop a membrane electrode assembly (MEA) with lower Pt loading and higher performance in proton exchange membrane fuel cells (PEMFCs), it is an important research issue to understand interfacial structure of Pt/C catalyst and ionomer and design the catalyst layer structure. In this study, we prepared short-side-chain Nafion-based ionomer dispersion using propylene glycol (PG) as a solvent instead of water which is commonly used as a solvent for commercially available ionomers. Cathode catalyst layers with different ionomer content from 20 to 35 wt% were prepared using the ionomer dispersion for the fabrication of four different MEAs, and their fuel cell performance was evaluated. As the ionomer content increased to 35 wt%, the performance of the prepared MEAs increased proportionally, unlike the commercially available water-based ionomer, which exhibited an optimum at about 25 wt%. Small size micelles and slow evaporation of PG in the ionomer dispersion were effective in proton transfer by inducing the formation of a uniformly structured catalyst layer, but the low oxygen permeability problem of the PG-based ionomer film should be resolved to improve the MEA performance.

• Journal of the Korea Institute of Construction Safety
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• v.2 no.1
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• pp.28-35
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• 2019

The average number of deaths in the construction industry reaches 500 per year, and in particular, it is confirmed that the type of accidents and deaths caused by disasters such as work platforms has occupied more than 60% of the total. In this study, we presented a structured and combined solution for technology, management, education, and cost that can solve systematically, politically, and external environmental factors as well as direct influence factors. In addition, we examined the safety and safety standards of domestic and international safety, and discussed implications. First, direct impact factors, organizational impact factors, policy influence factors, and external environmental impact factors were examined and classified into technical, education, and institutional dimensions. Second, in relation to the installation of the work scaffold, the standards (OSHA 1926.452), UK (The Work at Height Regulations 2005 No.735, BS5975), Japan (Labor Safety and Sanitation Regulations) and Germany (DIN 4420_4, DIN EN12810). In the case of domestic safety standards, similar to the foreign safety standards, safety measures such as materials and specifications are applied. However, details related to the installation, assembly and structure of the work platform are somewhat different from those in the United States and the United Kingdom excluding Japan. Using the results of this study, it is possible to understand the cause of the accident of foot pedestrian accident more systematically and comprehensively, and safety managers and researchers are expected to help in the accident investigation.

• Journal of The Korean Association For Science Education
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• v.39 no.3
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• pp.405-414
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• 2019

As a case study, we analyzed the professor's teaching professionalism in college of science-engineering based on pedagogical content knowledge. Two professors from the college of science-engineering located in Chungcheongbuk-do participated in this study. After collecting their syllabi, we observed their classes and conducted semi-structured interview before and after the classes. Analysis were conducted on their syllabi, taped videos, field notes and transcripts of the interview. As a result, both professors' orientation to teaching was not only related to learning subject matter knowledge, but also developing job competencies or communication skills. Their orientations were transformed according to the educational situation. After establishing the final learning goals, the professors organized weekly plan by listing the topics. However, they were unaware that the goals of each topic should be presented in detail in the class. Also, one of them presented a lack of understanding of the students' prior knowledge and showed low understanding of what aspects of the topics make students difficult to learn. In addition, the two professors applied various teaching strategies such as giving examples, questioning, and problem solving, but the degree of students' participation was not enough in the process of teaching. In the aspect of assessment, the professors had low understanding in students' achievement or feedback. Based on the results of the analysis, this study proposed methods and strategies for improving the teaching professionalism of science-engineering professors.

• Korean Journal of Psychosomatic Medicine
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• v.27 no.1
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• pp.69-76
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• 2019

Objectives : The purpose of this study was to examine the prevalence and clinical characteristics of nonsuicidal self-injury (NSSI), and its association with suicide attempts among clinically depressed adolescents in Korea. Methods : In total, 113 depressed adolescents aged 12-18 years in South Korea were enrolled in this study. We assessed sociodemographic and clinical characteristics including suicidality and non-suicidal self-injury (NSSI) using various self-reported scales and semi-structured interview for diagnosis of psychiatric disorders. Demographic and clinical characteristics of the subjects were compared between NSSI and non-NSSI groups. We examined significant predictors of suicide attempts using logistic regression analysis. Results : Among 113 depressed participants, 48 (42.1%) adolescents were classified into the NSSI group. In the NSSI group, there were significantly more females, showed higher depression, higher state-anxiety, and more suicide ideation. The most predictive factors of suicide attempts were history of NSSI, observed suicide/NSSI behaviors of their family or friends, and total state anxiety score. Conclusions : NSSI is more common problem among clinically depressed adolescents and history of NSSI is a significant predictor of present suicide attempts. To include the assessment of NSSI for clinically depressed adolescent may be crucial for intervention programs for high risk adolescents of suicide in Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.403-416
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• 2019

The focus of this study is on the new instructional and pedagogical application of teaching English as a foreign language (TEFL) with technology and by gender. Participants comprised 204 TEFL students in Korea. The study was conducted in the 2017 academic year. For this study, all participants attended English class using technology for three hours a week. Course syllabus, lecture notes, and other study materials were uploaded to the school website. Homework assignments, quizzes, and exams were also distributed through the website. To ascertain whether there are any differential effects from gender on learning English as a foreign language using technology, the quantitative materials included pre- and post-tests. This study also adopted qualitative methods, with structured interviews to obtain participants' comprehensive view of technology-assisted English lessons. Paired sample t-tests and independent t-tests were administered to analyze the quantitative data. The qualitative data were analyzed with the content analysis method. Findings show that both male and female students improved their English-speaking skills using technology. However, no gender difference was found in technology-assisted TEFL. Technology use for learning English also resulted in both genders' positive perceptions of language lessons. Based on these findings, this study yields practical implications for TEFL teachers in Korea.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.4
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• pp.161-178
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• 2019

The purpose of this study is to analyze the effect of characteristics of the online shopping mall website and the service quality factors required on the online service on the reliability and repurchase intention. Through this, the key customer response service and operation management strategy can be proposed for the growth of kidult online shopping mall which is continuously spreading. Also, implications for development direction can be suggested. For this purpose, the ES-QUAL and E-Rec-S-QUAL factors proposed by Parasuraman et al.(2005) were set as independent variables, as well as professionalism, diversity, playfulness, and personalization, and website reliability as a mediating factor, and repurchase intention as a dependent variable. For the analysis, a structured questionnaires survey was conducted to 200 domestic online shopping mall users. The main results are as follows. First, the professionalism, personalization in the characteristics, and service quality factors had positive effects on website reliability. Second, playfulness, personalization in the characteristics, and service quality factors had positive effects on repurchase intention. Third, website reliability had a positive effect on repurchase intention. Fourth, website reliability was found to mediate the relationship between predictive (independent) variables and dependent variables. The above results show that if a professional online shopping mall is equipped with online service quality and establish personalization through enhancing the professionalism, the online shopping mall can form a website reliability and expect to build continuous relationship with customers. In addition, implications can be suggested for future customer response service and operation management strategies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.14-18
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• 2019

The conductivity of a semiconductor is primarily determined by the carriers. To achieve higher conductivity, the number of carriers should be high, and an energy trap level is created so that the carriers can cross the forbidden zone with low energy. Carriers have a crystalline binding structure, and interfacial mismatching tends to make them less conductive. In general, high-concentration doping is typically used to increase mobility. However, higher conductivity is also observed in non-orthogonal conjugation structures. In this study, the phenomena of higher conductivity and higher mobility were observed with space charge limiting current due to tunneling phenomena, which are different from trapping phenomena. In an atypical structure, the number of carriers is low, the resistance is high, and the on/off characteristics of capacitances are improved, thus increasing the mobility. ZTO thin film improved the on/off characteristics of capacitances after heat treating at $150^{\circ}C$. In charging and discharging tests, there was a time difference in the charge and discharging shapes, there was no distinction between n and p type, and the bonding structure was amorphous, such as in the depletion layer. The amorphous bonding structure can be seen as a potential barrier, which is also a source of space charge limiting current and causes conduction as a result of tunneling. Thus, increased mobility was observed in the non-structured configuration, and the conductivity increased despite the reduction of carriers.

• Journal of Digital Convergence
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• v.17 no.7
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• pp.265-274
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• 2019

The purpose of this study was to know the difference in pain, sleep, self-care behavior in patients performed by sternotomy and robotic minimally invasive cardiac surgeries. The participants were 64 patients with sternotomy and 64 patients with minimal thoracotomy in heart valve surgeries at a tertiary hospital in Seoul. Data were analyzed using descriptive statistics, ${\chi}^2$ test, paired t-test. with SPSS/WIN(22.0). The participants with minimally invasive thoracotomy felt severe pain than the patients with thoracotomy at post operation day 2 & 5. The severe pain site were the surgical site in both groups. The participants with sternotomy had better sleep than minimally invasive thoracotomy patients. Self-care behavior was higher in the minimally invasive thoracotomy group. Therefore, despite the many advantages of robotic surgery such as rapid recovery and shortening of length of stay in hospital, accurate pain assessment and application of differentiated protocols are needed for the management of pain in the patients with robotic minimally invasive cardiac surgeries. In addition, a structured education program intervention is needed to improve comfort by considering gender, age, and method of operation.

• Korean Journal of Biological Psychiatry
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• v.25 no.4
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• pp.118-124
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• 2018

Objectives Although impulsivity has long been thought as an important factor influencing suicidal behaviors, it is unknown whether impulsivity increases the risk of dying from suicidal behaviors and what specific component among constructs of impulsivity contributes to the risk of dying among suicide attempters. Methods To elucidate the association between impulsivity and medical lethality of suicide attempt among suicide attempters, we consecutively recruited 46 suicide attempters who visited an emergency room of a general hospital located in a metropolitan area, Seoul, Republic of Korea, due to suicide attempts and consented to participate in this study. Then we assessed medical lethality with the Beck Lethality Scale (LS) and impulsivity with the Korean version of the Barratt Impulsiveness Scale-11-Revised (BIS). Demographic variables were obtained from medical records and structured social work reports for suicide attempters. Results Although total scores of the BIS did not correlate with LS scores, only the scores of self-control, that is one of the Barrett's six theoretical constructs of impulsivity in which the higher score indicates less self-control and more impulsivity, had a significant positive correlation with scores of LS (p = 0.003). The association remained significant after adjusting for variables known to affect suicide lethality such as job status, recent alcohol consumption, diagnosis of depressive disorders, and having a plan for suicide (${\beta}=0.429$, p = 0.009). Conclusions Not impulsivity in general, but poor self-control, in particular, predicts lethal suicidal behaviors among suicide attempters. The degree of self-control should be evaluated when assessing patients with elevated suicide risk, and proper measures should be installed to prevent possible future lethal suicide attempts.

• Journal of the Korean Society for information Management
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• v.36 no.2
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• pp.7-29
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• 2019

The purpose of this study is to investigate the status of specialized services, user experience, and the overall satisfaction for the specialized library users, and based on the ISA method, compare the specialized theme data, specialized service place, specialized program, specialized theme area facilities and environment, and derive issues of the specialized library operation and improvement measures. Consequently, first, when selecting the theme of the specialized library, the theme ought to be selected to reflect the regional characteristics, history and demographics of the library, and the demand survey of the local residents and library users would need to be considered. Second, when planning the specialized program, the specialized library ought to consider operating differentiated programs based on the program operator who has the expertise to improve the quality of the program. Furthermore, sufficient theme related books and space must be secured, and moreover, the program must be planned in connection with the book collection. Third, the specialized library should be so structured as to ensure that the space may serve specialized themes provided by the library in order to provide specialized collections, services, and information services for the users. In addition, reflecting the needs of the users in designing the space must be considered.