• Applied Chemistry for Engineering
• /
• v.31 no.6
• /
• pp.639-645
• /
• 2020

Among the components of redox flow battery (RFB), the electrode serves as a diffusion layer of an electrolyte and a path for electrons and also is a major component that directly affects the RFB performance. In this paper, chloric/sulfuric mixed acidwas used as a supporting electrolyte in RFB system with Fe2+/Fe3+ and V2+/V3+ as redox couple. The optimum electrode and activation temperature were suggested by comparing the capacity, coulombic efficiency and energy efficiency according to the electrode type and activation temperature. In the RFB single cell evaluation using 5 types of carbon electrodes used in the experiments, all of them showed close to the theoretical capacity to retain the reliability of the evaluation results. GFD4EA showed relatively excellent energy efficiency and charge/discharge capacity. In order to investigate the electrochemical performance according to the activation temperature, GFD4EA electrode was activated by heat treatment at different temperatures of 400, 450, 500, 600 and 700 ℃ under an air atmosphere. Changes in physical properties before and after the activation were observed using electrode mass retention, scanning electron microscope (SEM), XPS analysis, and electrochemical performance was compared by conducting RFB single evaluation using electrodes activated at each temperature given above.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.15 no.6
• /
• pp.1-26
• /
• 2020

The term 'Unicorns' in the corporate ecosystem was firstly introduced by Aileen Lee in 2013. It has been actively discussed in South Korea particularly to compare the level of the 'start-up ecosystem' from a global perspective. Accordingly, the Korean government has recently set a policy goal 'to nurture 20 Korean unicorn companies by 2022'. While the phenomenon of 'Unicorn Club Company' has been brought to the level of policy objectives and spread more widely to the public, existing academic research to understand its substantial and underlying implications has been insufficient. First, in this study, the characteristics of 479 'Unicorn Club' companies in 2019 were analyzed in-depth. Previous research has focused on the general status and trend by analyzing the number of unicorn companies by country and industry classifications. However, this study conducted a qualitative exploratory analysis by investigating descriptive statistics about unicorn companies, including their investors, while providing case studies. Also, cluster analysis, ANOVA, and multi-level regression were employed for quantitative exploration. The characteristics of individual companies were examined based on the "ERIS Model (Entrepreneur - Industry(Market) - Resource - Strategy Model)". Secondly, factors influencing its valuations were examined in connection with the previously analyzed characteristic variables and investor characteristics. Finally, based on these, the future direction of the "Unicorn Phenomenon" from the perspective of "Enterprise Ecosystem" and productively using it from the perspective of the public policy is suggested.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.709-718
• /
• 2020

Even after Fukuyama declared "The End of History" in 1989, the challenge to liberal democracy continues. Controversy about totalitarianism is constantly being raised both internally and externally in democratic countries and leaders, as well as the US-China war of supremacy. In this paper, I explored a hypothesis about the totalitarian process, and to explain this hypothesis, I analyzed the case of Venezuela, which was once referred to as a welfare model state. This paper presupposes Fukuyama's insistence on the universality of liberal democracy but considers the last man Nietzsche argues for the last man he assumes. Accordingly, the process of totalitarianism was viewed as a process in which totalitarianism was institutionalized and spread internationally through the linkage and interaction of the last fallen humans, the masses, and totalitarians in the international and domestic environments. According to this hypothesis, the Bol?var Revolution and Chavez show the process of transformation into a typical quasi-totalism. Although the Venezuelan people preferred democracy, they remained the last man who had become a man of "rich consciousness." While investigating this hypothesis, it was confirmed that extensive and interdisciplinary studies such as digital t otalitarianism and the development of science and technology should be followed.

• Korean Journal of Clinical Laboratory Science
• /
• v.53 no.1
• /
• pp.49-59
• /
• 2021

This study investigated the use of real-time PCR melting curves for the diagnosis of blaKPC and blaNDM genes among the most frequently detected carbapenemase-producing Enterobacteriaceae in Korea. As a means of addressing the shortcomings of phenotype tests and conventional PCR. The modified Hodge test confirmed positivity in 25 of 35 strains, and carbapenemase inhibition testing confirmed positivity in 14 strains by meropenem+PBA or meropenem+EDTA. PCR analysis showed amplification products in 25 strains of Klebsiella pneumoniae carbapenemases (KPC), 10 of K. pneumoniae, 5 of E. coli, 5 of A. baumannii, 4 of P. aeruginosa, and 1 of P. putida. New Delhi metallo β-lactamase (NDM) identified amplification products in 8 strains, that is, 2 K. pneumoniae, 3 E. coli, 1 P. aeruginosa, 1 E. cloacae, and 1 P. retgeri strains. Real-time PCR melting curve analysis confirmed amplification in 25 strains of KPC and 8 strains of NDM, and these results were 100% consistent with PCR results. In conclusion, our findings suggest early diagnosis of carbapenem resistant Enterobacteriaceae by real-time PCR offers a potential means of antibacterial management that can prevent and control nosocomial infection spread.

• Journal of the Korean Society of Radiology
• /
• v.15 no.4
• /
• pp.555-564
• /
• 2021

Thalamus is known to play an important role in the regulation of nerve function. Thalamus, located in the center of the brain, is involved in sleep, arousal, and emotional regulation, and has been reported to be associated with multiple sclerosis, essential tremors, and neurodegenerative diseases such as Parkinson's disease. In addition, it has been reported that iron deposits in the thalamus can cause depressive symptoms with age. Although there are discrepancies between studies, it can be deduced that the thalamus region has a clear effect on neurological disorders due to a strong relationship between the thalamus and neurological functions such as emotional control and processing. Through tractography analysis, the connectivity between the detailed areas of each subcortical region was investigated in the form of a matrix, showing strong connectivity and weak interhemispheric connectivity. In the 59> group, the WM connectivity of thalamus was found to be weaker than those of the two groups. Comparisons between the two groups showed that the young groups (10-39 and 40-59) had higher connection intensity than the 59> group and that statistically significant differences in 3 connection pathways were found in each hemisphere. A decrease in thalamus-related connection strength in aging has shown that it can affect emotional and neurological disorders such as anxiety and depression, and network measurements can help assess cognitive impairment across clinical conditions.

• Korean Journal of Environment and Ecology
• /
• v.35 no.4
• /
• pp.347-376
• /
• 2021

Investigating and evaluating regionally distributed plant resources provide fundamental information (inventory) to conserve plant diversity in target areas. Nevertheless, the examination of inventory to collect information in areas with little interest has been insufficient. In this study, the vicinity of Mt. Baegamsan(1,004m) was investigated for plant resources in the central and southern part of the Korean peninsula, which has received low interest. Nine surveys identified a total of 638 taxa consisting of 108 families, 339 genera, 572 species, 12 subspecies, 49 varieties, and 5 forms. One taxon was designated to be the endangered wild plant by the Ministry of Environment, and a total of 29 taxa were designated to be endemic species in Korea. Floristic target species identified by the surveys included 1 taxon for grade V, 13 taxa for grade IV, 36 taxa for grade III, 29s taxa for grade II, and 34 taxa for grade I. A total of 38 taxa were identified to be naturalized plants, and 3 of them were designated as invasive alien plants by the Ministry of Environment. There was a difference in plant distribution between western and eastern areas of Mt. Baegamsan. The endangered and valuable plants for conservation were mainly identified from Mt. Baegamsan peak area, the ridge, and the western area. Considering the plant distribution, the Mt. Baegamsan region, located on Nakdong-jungmaek, was estimated to be dispersal routes for plant expansion and retreat.

• Journal of Life Science
• /
• v.31 no.8
• /
• pp.755-760
• /
• 2021

Swine diarrhea is a livestock disease that causes huge economic losses to pig farms. In general, diarrhea occurs because of the proliferation of pathogenic Escherichia coli (E. coli). The toxins produced by the proliferated E. coli cause edema in pigs. Although the proliferation of these coliforms can be prevented by using a vaccine, the vaccines containing chemically produced dead bacteria are not very effective, making it difficult to control the proliferation of E. coli. Therefore, there is a need to develop new, more effective vaccines. In this study, we prepared killed F4+ and F18ab+ E. coli, which induce diarrhea and edema in pigs, using the extracts of immune-induced silkworms containing antimicrobial peptides and examined their availability as a killed-bacteria vaccine. First, the antimicrobial activity analysis of the prepared immune-induced silkworm extract was conducted using the radial diffusion assay. The results showed high activity against both F4+ and F18ab+ E. coli. The production efficiency of E. coli dead cells was determined using the colony-counting method. The concentration of the E. coli dead cells was the highest (50 mg/ml) when treated at 4℃. In addition, the analysis of the prepared dead cells using a transmission electron microscope confirmed that E. coli leaked out of the cytoplasm and the cell membrane remained intact. Therefore, F4+ and F18ab+ E. coli produced using immune-induced silkworms extract are considered to be highly available as bacterial ghost vaccines that can help prevent swine diarrhea and the resulting edema.

• Journal of The Korean Association of Information Education
• /
• v.25 no.2
• /
• pp.423-436
• /
• 2021

In the future, artificial intelligence (AI) technology is expected to become a general-purpose technology (GPT), and it is predicted that AI competency will become an essential competency. Several nations around the world are fostering experts in the field of AI to achieve technological proficiency while working to develop the necessary infrastructure and educational environment. In this study, we investigated the status of software education at the liberal arts level at 31 universities in Seoul, along with precedents from domestic and foreign AI education research. Based on this, we concluded that an AI literacy education model is needed to link software education at the liberal arts level with professional AI education. And we classified 20 AI-related lectures released in the KOCW according to the AI literacy competencies required; based on the results of this classification, we propose a model for AI literacy education in the liberal arts for undergraduate students. The proposed AI literacy education model may be considered as AI·SW convergence to experience AI along with literacy in the humanities, deviating from the existing theoretical and computer-science-based approach. We expect that our proposed AI literacy education model can contribute to the proliferation of AI.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.20 no.6
• /
• pp.14-25
• /
• 2021

With the spread of COVID-19 and the government policy of social distancing, the demand for subways and buses is decreasing, whereas the demand for public bicycles and personal transportation is increasing. Hence, research is needed to understand the characteristics of this phenomenon and to prove the statistical reliability of the correlation between the subway and shared bicycle demands. In this study, the correlation between the number of confirmed COVID-19 cases and the replacement rate of subway and public bicycle demands was examined, but the statistical significance was not significant. However, during the period of September to December 2020, in which the number of confirmed COVID-19 cases in Seoul started to increase rapidly, there was a correlation between the number of confirmed COVID-19 cases and the replacement ratio. If the number of confirmed COVID-19 cases increases by more than a certain number, public bicycles are expected to play a significant role as alternates to the subways. It is expected that the role of public bicycles will increase, and that it is possible to suggest the direction of transportation operation and policy establishment for the continuation of COVID-19 countermeasures in field demonstration after elementary technology development. It is also expected that this study will suggest a direction for future development and policymaking.

• Journal of the Economic Geographical Society of Korea
• /
• v.25 no.1
• /
• pp.131-146
• /
• 2022

The purpose of this study is to examine the locational characteristics of cafes in Jeju Island and the changes. For the purpose, we identify the spatial distribution patterns of openings and closings by period from the first opening of cafes in Jeju Island to the present. In particular, we analyze the spatial distribution characteristics found in the locations of cafes that have been opened and closed after the outbreak of COVID-19, in which new stores have significantly increased. In addition, we identify the regional attributes and the influence of online that have affected the distribution of currently open cafes and cafes that have opened or closed during the COVID-19 outbreak. As a result of empirical analysis, Jeju Island is a tourist destination and island region with the characteristics of determining major destinations through information search, showing a different distribution form from the location of cafes in inland cities. In particular, as a result of frequency analysis by extracting keyword search volume for cafes in Jeju Island, online accessibility such as information search for new areas and places in Jeju Island has become more diversified and expanded after COVID-19. In addition, as a result of calculating the distance to cafes by road size, the relationship between physical location and road accessibility, which has traditionally been an important factor, was relatively low. This study is meaningful in that it revealed the distribution patterns and characteristics of cafe locations in Jeju Island by reflecting the influence of online and offline.