• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.11-11
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• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.941-948
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• 2022

Disaster response robots are deployed to disaster sites where human access is difficult and dangerous. The disaster response robots explore the disaster sites prevent a structural collapse and perform lifesaving to minimize damage. It is difficult to operate robots in the disaster sites due to rough terrains where various obstacles are scattered, communication failures and invisible environments. In this paper, we developed a series connectable wheeled robot module. The series connectable wheeled robot module was developed into two types: an active driven robot module and a passive driven robot module. A wheeled robot was built by connecting the two active type robot modules and one passive type robot module. Two robot modules were connected by one DoF rotating joint, allowing the wheeled robot to avoid obstructions in a vertical direction. The wheeled robot performed driving and obstacle avoidance using only pressure sensors, which allows the wheeled robot operate in the invisible environment. An obstacle avoidance experiment was conducted to evaluate the performance of the wheeled robot consisting of two active driven wheeled robot modules and one passive driven wheeled robot module. The wheeled robot successfully avoided step-shaped obstacles with a maximum height of 80 mm in a time of 24.5 seconds using only a pressure sensors, which confirms that the wheeled robot possible to perform the driving and the obstacle avoidance in invisible environment.

• Molecules and Cells
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• v.43 no.4
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• pp.350-359
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• 2020

Pathogenic aminoacyl-tRNA synthetases (ARSs) are attractive targets for anti-infective agents because their catalytic active sites are different from those of human ARSs. Mupirocin is a topical antibiotic that specifically inhibits bacterial isoleucyl-tRNA synthetase (IleRS), resulting in a block to protein synthesis. Previous studies on Thermus thermophilus IleRS indicated that mupirocin-resistance of eukaryotic IleRS is primarily due to differences in two amino acids, His581 and Leu583, in the active site. However, without a eukaryotic IleRS structure, the structural basis for mupirocin-resistance of eukaryotic IleRS remains elusive. Herein, we determined the crystal structure of Candida albicans IleRS complexed with Ile-AMP at 2.9 A resolution. The largest difference between eukaryotic and prokaryotic IleRS enzymes is closure of the active site pocket by Phe55 in the HIGH loop; Arg410 in the CP core loop; and the second Lys in the KMSKR loop. The Ile-AMP product is lodged in a closed active site, which may restrict its release and thereby enhance catalytic efficiency. The compact active site also prevents the optimal positioning of the 9-hydroxynonanoic acid of mupirocin and plays a critical role in resistance of eukaryotic IleRS to anti-infective agents.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1597-1602
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• 2012

In this study, we determined the 3D-structure of Arabidopsis thaliana KAPAS by homology modeling. We then investigated the binding mode of compounds obtained from in-house library using computational docking methods. From the flexible docking study, we achieved high dock scores for the active compounds denoted in this study as compound $\mathbf{3}$ and compound $\mathbf{4}$. Thus, we highlight the flexibility of specific residues, Lys 312 and Phe 172, when used in active sites.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.630-635
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• 2008

An urban transit is representative public transportation which lots of people take everyday. Especially, the station of urban transit is one of the very important public civil infrastructures. From the teachings of subway fire disaster occurred at Daegu on 2003, a certain incident might create large numbers of deaths or injuries and a lot of damages to the subway station without having an accurate grasp of emergency situation and doing proper action on the situation. Therefore, the passive surveillance system, which means the present CCTV based system, needs to be changed into the active one. The active surveillance system is the CCTV based system with intelligent softwares which affords to prevent a certain incident or trouble and its aggravation. In this paper, the state of the art of the representative companies developing intelligent softwares and its application sites of Australia and Hong Kong are briefly introduced. Finally, with the consideration of its recent trends, some technical contents for the intelligent surveillance system of domestic urban transit are briefly described.

• Journal of the Korean Dietetic Association
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• v.6 no.1
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• pp.1-8
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• 2000

Nowadays social environment is rapidly changed toward globalization and information age, and which demands the new paradigm for active utilization of information system in many fields. The increasing availability and ease of accessibility of the internet using world wide web have resulted in an enormous increase in the amount of nutrition information in countries with advanced information technology. However, Domestic web services in nutrition field are neither diverse nor professional currently. Nutrition experts need to take advantage of the resources offered though the web and take an active role in providing reliable and accurate information and preventing the growth of nutrition misinformation though web. Nutrition web sites on a variety of subjects should be developed depending upon the objectivity of nutrition resources and the target clients. Nutrition-related organizations are responsible for monitoring nutrition web information and encouraging open discussion and evaluation of hot issues among experts, and between experts and clients through the internet.

• Journal of the Korean Institute of Educational Facilities
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• v.6 no.1
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• pp.5-20
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• 1999

With the advent of internet, the modern society is enjoying the benefits of the information age. As one of undesirable side effects of utilization of internet, however, it is often mentioned that young students are helplessly exposed to inappropriate and unqualified information. Therefore, in this paper, we will clarify the nature of inappropriate information to the younger generation and will argue for the needs of protecting the youth from inappropriate information. Especially the merits and limits of often motioned five different protective and regulatory measures are presented and analyzed, those are, establishment of acceptable use policy, active utilization of supervisory organization, promotion of Internet rating system, installation of filtering software, and legal and regulatory protection. As a fundamental means of resolving the problems, however, enforcement of systematic information literacy education, promotion of active utilization of sound information, development of search engines for the youth, design of diverse filtering softwares which can be selected by users, and increased attention by parents and teachers are suggested.

• Journal of the Korean Society of Safety
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• v.36 no.5
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• pp.36-42
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• 2021

Portable ladders are widely used as ascend and descend pathways and platforms for works at height at residential and industrial sites. In the last 10 years, 267 fatalities and 36,571 accidents related to portable ladders have been reported, suggesting a need to develop countermeasures to prevent such accidents. In this study, an in-depth focus group interview (FGI) was conducted with various stakeholders of portable ladders to survey the current usage and requirements for improving work safety. A new portable ladder called active platform ladder was developed based on the requirements suggested by the FGI. A stability test confirmed that the developed ladder is more stable than conventional ones, suggesting that it can reduce the fall accidents.

• Genomics & Informatics
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• v.21 no.2
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• pp.25.1-25.12
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• 2023

Adaptation of infections and hosts has resulted in several metabolic mechanisms adopted by intracellular pathogens to combat the defense responses and the lack of fuel during infection. Human tuberculosis caused by Mycobacterium tuberculosis (MTB) is the world's first cause of mortality tied to a single disease. This study aims to characterize and anticipate potential antigen characteristics for promising vaccine candidates for the hypothetical protein of MTB through computational strategies. The protein is associated with the catalyzation of dithiol oxidation and/or disulfide reduction because of the protein's anticipated disulfide oxidoreductase properties. This investigation analyzed the protein's physicochemical characteristics, protein-protein interactions, subcellular locations, anticipated active sites, secondary and tertiary structures, allergenicity, antigenicity, and toxicity properties. The protein has significant active amino acid residues with no allergenicity, elevated antigenicity, and no toxicity.

• Journal of the Korean Chemical Society
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• v.68 no.2
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• pp.87-92
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• 2024

The commercialization of rechargeable metal-air batteries is extremely desirable but designing stable oxygen reduction reaction (ORR) catalysts with non-noble metal still has faced challenges to replace platinum-based catalysts. The nonnoble metal catalysts for ORR were prepared to improve the catalytic performance and stability by the thermal decomposition of ZIF-8 with optimum cobalt loading. The porous carbon was obtained by the calcination of ZIF-8 and different loading amounts of Co nanoparticles were anchored onto porous carbon forming a Co/PC catalyst. Co/PC composite shows a significant increase in the ORR value of current and stability (500 h) due to the good electronic conductive PCN support and optimum cobalt metal loading. The significantly improved catalytic performance is ascribed to the chemical structure, synergistic effects, porous carbon networks, and rich active sites. This method develops a new pathway for a highly active and advantageous catalyst for electrochemical devices.