• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.432.1-432.1
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• 2014

Hydroxyapatite (Ca10(PO4)6(OH)2) is known as the main inorganic component of mature mammalian bones and teeth. Because of its biocompatibility, hydroxyapatite has attracted much attention due to its potential applications in many biomedical researches. Here, we tested a therapeutic potential for the use of hydroxyapatite as an anticancer drug delivery vector. We prepared various types of hydroxyapatite having different chemical contents and morphologies using hydrothermal synthesis. The capability of hydroxyapatite as drug delivery materials was examined by adsorption kinetics of 5-fluorouracil molecules, a common anticancer drug, in phosphate buffered saline. We find that hydroxyapatite with smaller crystal size and higher phosphate contents shows improved adsorption property. Given that hydroxyapatite provides a scaffold for bone regeneration, these results highlight a potential use of hydroxyapatite in therapies aimed at osteosarcoma.

• 한국안전학회지
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• 제13권3호
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• pp.67-73
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• 1998

The technology for neutralizing static electricity by soft X-ray radiation has been newly developed. This technology involves ionization of gas molecules in the vicinity of a charged substrate to generate ions and electrons to reduce electrostatic potential. The ULSI device substrate and liquid crystal display substrate tend to get charged instantly to a high potential level when they are handled in the manufacturing process. Soft X-ray radiation is adequate in air or $O_2$ gas at atmospheric pressure. This newly developed neutralization method is effective to be superior to the conventional technique, i.e., an ionizer by using corona discharge ,in every aspect. The new method features excellent neutralization capability and is able to completely reduce electrostatic potential to 0 V within a short time. Moreover, this is a very clean antistatic technology free from particle generation ,ozone generation, and electromagnetic noise, which are problems in using the corona discharge ionizer.

• 전기학회논문지
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• 제64권5호
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• pp.732-738
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• 2015

In ac discharge, emission efficiency shows an time-varying characteristics during discharge. The phenomenon is caused by the potential distribution changes during the discharge, which indicates that a specific potential distribution can contribute to a high improvement of the emission efficiency. To create an artificial environment for a potential distribution favorable to emission efficiency, we used the asymmetric electrode structure and proved the capability. Our results showed that the ratio of the area of anode to cathode became larger, the emission efficacy was greatly improved.

• 유통과학연구
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• 제12권9호
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• pp.25-38
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• 2014

Purpose - Our study aims to analyze and assess aeronautics transport, to bring comprehensive insight about the existing potential in the new member states, candidate countries, potential candidate countries, and associated states. Methodology - The evaluation was carried out by applying qualitative methodology to the research results and on existing capabilities, to assess the overall research capability in the aeronautics transport mode of each country and region, in the European context. Results - Overall, countries with the strongest potential are the Czech Republic, Poland, Hungary, and Romania. The aeronautics research potential was evaluated as weak in as many as 11 countries, with Estonia, Bosnia-Herzegovina, Macedonia, Montenegro, Albania, and Moldova being evaluated as weak in all categories, and Latvia, Croatia, and Serbia being evaluated as weak overall but having at least one category evaluated as medium. Conclusion - Based on the research findings, there are recommendations regarding both the research policy and research activities related to the aeronautics transport mode. The findings contribute to the further development of EU aeronautics research and the aviation industry.

• 한국동물위생학회지
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• 제40권4호
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• pp.265-275
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• 2017

The production of enzymes that help digestion, assimilation of essential nutrients, and prevent pathogenic bacteria are important for probiotics used in aquaculture. The objective of this study was to investigate enzyme activities for macromolecular organic matters and antimicrobial properties of the selected potential probiotics isolated from gut of surf clam (Tresus keenae) against well-known shellfish-pathogenic bacteria. Among 65 isolates from guts of 60 surf clams, seven Bacillus strains with outstanding degradation capability of macromolecule organic matter were selected as potential probiotics as follows: TKI01 (B. vietnamensis), TKI02, TKI26 (B. thuringiensis), TKI14, TKI32, TKI42 (B. amyloliquefaciens), and TKI18 (B. stratosphericus). After in vitro antimicrobial activity test was performed against five shellfish-pathogenic bacteria including Listonella anguillarum, Vibrio parahaemolyticus, V. splendidus, V. harveyi, V. tubiashii, PCR assay was performed to detect bacteriocin-producing strain. PCR results revealed that the five Bacillus strains possessed diverse bacteriocin genes including ericinA, coagulin, surfactin, iturin, bacyllomicin, fengycin, bacylisin, subtilin, and lantibiotics. In the present study, the selected seven Bacillus strains showed different enzyme activities according to types of macromolecule organic matters. And their antimicrobial activities varied based on the species of pathogenic bacteria. In addition, at least five Bacillus strains had genetic potential to produce several natural lipopeptide antibiotics that may help biological control of surf clam aquaculture. Therefore, mixed use of probiotics might show co-operative effect and increase the efficiency of probiotics rather than separate use. To the best of our knowledge, it is the first report on antimicrobial properties of Bacillus species isolated from surf clam.

• 한국물환경학회지
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• 제34권6호
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• pp.661-668
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• 2018

Geosmin is volatile metabolites produced by a range of filamentous cyanobacteria which causes taste and odor problems in drinking water. Molecular ecological methods which target biosynthetic genes (geoA) are widely adopted to detect geosmin-producing cyanobacteria. The aim of this study was to investigate the potential production capability of 8 strains isolated from the Nakdong River. Ultimately, a suggestion for a genetical monitoring tool for the identification of geosmin producers in domestic waters was to be made. Geosmin was detected using solid phase microextraction gas chromatography mass spectrometry (SPME GC-MS) in two strains of Dolichospermum plactonicum (DGUC006, DGUC012) that were cultured for 28 day. The highest concentrations during the experiment period was $17,535ngL^{-1}$ and $14,311ngL^{-1}$ respectively. Additionally, geoA genes were amplified using two primers (geo78F/971R and geo78F/982R) from strains shown to produce geosmin, while amplification products were not detected in any of non-producing strains. PCR product (766 bp) was slightly shorter than the expected size for geosmin producers. According to the BLAST analysis, amplified genes were at nucleotide level with Anabaena ucrainica (HQ404996, HQ404997), Dolichospermum planctonicum (KM13400) and Dolichospermum ucrainicum (MF996872) between 99 ~ 100 %. Both strains were thus confirmed as potential geosmin-producing species. We concluded that the molecular method of analysis was a useful tool for monitoring potential cyanobacterial producers of geosmin.

• 한국융합학회논문지
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• 제4권4호
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• pp.1-5
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• 2013

본 연구는 회수물류의 실행의 중요성이 강조되고 있는 가운데, 기업이 보유한 회수물류역량이 공급사슬상의 협력기업들 간의 관계에서 기업의 수익을 향상시키며, 나아가 협력기업들 간의 협력만족도에도 긍정적인 영향을 미칠 수 있음을 보이고자 한다. 회수물류역량에 관한 선행연구들에서는 주로 최종조립자와 소비자간의 관계에서만 회수물류의 중요성을 다루고 있을 뿐 공급사슬 상의 협력 기업들 간의 관계에서 회수물류역량의 역할에 대한 연구는 거의 이루어지지 않은 실정이다. 회수물류의 실행은 자산가치를 복구하는 효과와, 재활용을 통한 비용감소 효과 및 이를 통한 이윤의 극대화의 성과와 관계가 있다. 이러한 회수물류역량은 협력기업들 간의 수익에도 영향을 미칠 뿐 아니라 협력 기업들 간의 협력 만족도에도 긍정적인 영향을 미칠 것으로 기대된다.

• 전기학회논문지
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• 제58권3호
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• pp.437-443
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• 2009

In recent years, electric power systems have been experiencing a rapid change due to the increasing electricity market. For the effective use of power system under the deregulated environment, it is important to make a fast and accurate calculation of the maximum available transfer capability (ATC) from a supply point to a demand point. In this paper, the purpose of this research is to calculate ATC fast and accurately for securing the stability of system and raising the efficiency as a result of anticipating transmission congestion according to transmission open access progressed in the future under the regulated environment of electricity market. In this paper, a study utilized a relation of the potential energy and energy function by which calculated CCT and then utilized a relation of PEBS for transient stability ATC calculation. In this paper, ATC was calculated as RPF and Energy Function method and calculation results of each method was compared. Contingence ranking method decided the weak bus by the Eigenvalues of Jacobian matrix and overloading branches by PI-index. As a result, a study proved the fast and accurate ATC calculation method considering transient stability suggested in this paper. Through the case study using New England 39 bus system, it is confirmed that the proposed method can be used for real time operation and the planning of electric market.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.293-299
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• 2008

One of the problems with the fault diagnosis of transformers based on dissolved gas is the inability to match the result of the different standards of fault diagnosis with real world standards. In this paper, the results of the different standards are analyzed using fuzzy logic and then compared with the empirical test. The proposed method is based on the standards and guidelines of the International Electrotechnical Commission (IEC), the Central Electric Generating Board (CEGB), and the American Society for Testing and Material (ASTM) and its main task is to assist the conventional gas ratio method. The comparison between the suggested method and existing methods indicates the capability of the suggested method in the on-line fault diagnosis of transformers. In addition, in some cases the existing standards are not able to diagnose the fault. For theses instances, the presented method has the potential of diagnosing the fault. In this paper, the information of three real transformers is used to show the capability of the suggested method in diagnosing the fault. The results validate the capability of the presented method in fault diagnosis of the transformer.

• 경영과학
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• 제29권3호
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• pp.91-105
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• 2012

This paper examines the investment efficiency of Korean venture capitals during 1987~2006 (20 years), focusing on their selection capability. Despite the Korean government's efforts, venture capital industry has evolved in a slow speed. Since the genesis of venture paradigm in Korea at 1997, venture capital industry as a macro unit has been fully discussed in Korean contexts. But venture capital's activities at micro level regarding each investment's outcome have not been examined. This study attempts to fill the voids of micro knowledge about each investment success rates by venture capitals. We analyzed venture investment records in 4,791 venture startups and their success rates. Their investment criteria were relevant to high potential industries and amount of tangible assets. But their criteria were not relevant to R&D intensity and financial growth of venture firms, which may indicate low level of maturity about Korean venture capital industry. We found that Korean venture capital's investment pattern may be originated from the low return of investment, so that efficiency of IPO markets is a prerequisite for the upgrade of venture capitals' efficiency. Some policy implications are discussed.