• Journal of the Korean Electrochemical Society
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• v.7 no.3
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• pp.143-147
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• 2004

An investigation upon the characterization of MCMB anodes with different vapor grown carbon fiber (VGCF) content for application in lithium polymer battery(LPB) was carried out. When VGCF material was used as conducting agent with MCMB active material, the impedance and the initial coulombic efficiency of test cells were found to decrease with the increasing amount of VGCF. On the other hand, as a function of added VGCF the discharge capacity and the utilization linearly with increased. Impedance of test cell with MCMB anode containing $6wt\%$ VGCF exhibited the lowest value whereas the impedance of $8wt\%$ VUF contained anode was similar to that of MCMB anode without VGCF. Interestingly, $6wt\%$ VUF contained anode showed the best battery characteristics. Internal resistance and rate capacity of the cell were. respectively, $0.918{\Omega}\;at\;25C\;and\;93\%$ at 2C. Generally, rate capability and the cycleability of MCMB based test cells with $4\~6wt\%$ VGCF content exhibited better results than the other cells. In the case of $6wt\%$ VGCF containing anode, the discharge capacity of the cell faded slowly with an ultimate charge-discharge cycling capacity of 178mAh/g at the 100th cycle. Thereafter, the discharge capacity faded negligibly and the utilization of the cell at the 100th cycle was more than $90\%$. The effect of addition of VGCF is discussed in detail.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.179-185
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• 2022

The purpose of this study is to provide new implications for the development and operation of programs and comparative studies in university policy by examining how core competencies of university students participating in tutoring programs affect learning satisfaction. For this purpose, 33 university students participated in the tutoring program before COVID-19 and 72 university students participated in the tutoring program after COVID-19 were surveyed and statistically processed. As a result, first, there was a positive correlation between self-innovation, challenge, communication, harmony, sincerity, problem solving and learning satisfaction among the components of core competencies of H university before COVID-19. There was a positive correlation between self-innovation, challenge, communication, harmony, sincerity, problem solving and learning satisfaction of core competencies after COVID-19. Second, in the pre-COVID-19 period, core competence had a high explanatory power on learning satisfaction, but there was no statistically significant factor in each of the remaining components except for the challenge. After COVID-19, core competence was secured with a high rate of explanatory power, self-innovation and harmony among the components of core competence were found to have a positive effect on learning satisfaction, and challenge was found to have a negative effect on learning satisfaction. The implications of this study are that when students participate in the tutoring program, it is necessary to emphasize the challenge factors and when they proceed in non-face-to-face, it is necessary to emphasize the self-innovation factors or the harmony factors rather than the challenge factors.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.810-811
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• 2008

현재 고온 초전도전력기기를 실용화하는데 교류손실이 문제가 되고 있다. 이러한 교류손실을 저감하기위해서 선재를 분할하는 방법에 대한 연구가 진행중이다. 분할된 초전도선재의 각 필라멘트의 전류분류가 일정하지 않을 경우 필라멘트의 임계전류 이상이 인가될 수 있다. 따라서 각 필라멘트에 흐르는 전류를 측정하여야 한다. 그러나 초전도선재의 필라멘트 각각의 전류를 측정하기는 어렵다. 본 연구에서는 초전도선재의 필라멘트의 각각의 전류를 비접촉 방식으로 측정할 수 있는 서치코일을 이용한 방법을 제안하였고 실험을 통해 이를 확인하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.348-348
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• 2010

신 차종의 개발 시, 기존 차량 모델을 사용하여 재 설계하는 방식에 의해 전례 없이 빠르게 차량 개발을 수행하고 있다. 또한 대부분의 이들 후속 차량은 공통 플렛폼 상에 설계되고 있으며, 일반적으로 충격, 구조 건전성, 생산 타당성 검토 등의 컴퓨터 시뮬레이션은 개발 프로세서 초기 단계에서 행하여 지고 있으나. NVH 엔지니어링은 차량 개발 프로세스의 매우 중요한 과정으로 되어 있음에도 불구하고, 실내 소음, 진동 승차감, 피로 수명 예측 등은 사용되는 해석 모델의 크기 및 복잡성으로 인하여 이들 성능 특성 평가 및 최적화는 아직 도전 과제이며, 본 논문에서는 몇몇 선진 OEM에서 수행되고 있는 NVH 개발 프로세스와 이를 가능케 하는 기법을 소개한다.

• The Optical Journal
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• s.101
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• pp.76-82
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• 2006

최근 무역흑자기조가 유지되고 있으며 2003년 이후 수출증가율이 수입증가율을 앞서나가고 있어 무역 흑자 규모가 2004년 약 200억불로 커지고 있다. 그러나 주요기간산업의 대일의존은 여전하다. 특히 광학산업을 포함한 기계산업은 역조규모가 가장 크며 대부분의 품목들이 대일수입에 의존하고 있고 그 뒤를 전자전기산업이 따르고 있다. 이처럼 한국의 자본재 산업은 해외에 의존하고 가공/조립을 통한 범용제품(후방산업) 양산에 치우쳐왔다. 따라서 기술개발능력이 있는 중소기업의 원천기술에의 도전을 적극적으로 지원하는 연구개발 사업이 필요하며, 기업이 보유한 특허와 같은 지적재산에 투자하는 지적재산캐피탈(IPC)을 도입하여 기술보유기업의 성장과 신기술의 시장진입을 도와야 할 것이다.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1059-1064
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• 1998

We have investigated various kind of graphite and MCMB6-28 to develop carbon negative electrode for lithium ion secondary battery. The interlayer length of them was $3.358{\sim}3.363{\AA}$ and the BET specific surface area was $2.95{\sim}26.15m^2/g$. From this study, When the interlayer of them was large and the BET specific surface area was high, the electrochemical characteristics of them was very excellent. Adding 0, 3, 5, wt% of KJ-Black as conducting agent to various graphitic carbon active materials, interface resistance of electrode and electrolyte was less, but rechargeability was better at 3 wt%. At constant current charge and discharge test, discharge capacity was small according to large current.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.488-497
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• 2013

The purpose of the study was to investigate the relationship between the degree of participation and flow for participants in ground, water, and air leisure sports-based tourism activities. A total of 437 participants' data was employed for the analyses (one-way ANOVA and multiple regression analysis) using SPSS Win 18.0 program. Main findings are as follows; First, there were differences in clear goals, transformation of time, loss of self-consciousness, challenge-skill balance, autotelic experience, unambiguous feedback, and sense of control out of flow dimensions based on types of leisure sports-based tourism activities. Second, participation period and frequence had positive effects on flow. Specifically, period had an influence on challenge-skill balance. clear goals: frequence had an effect on challenge-skill balance, transformation of time, clear goals, autotelic experience, unambiguous feedback, and sense of control: intensity had an influence on transformation of time and autotelic experience.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.255-258
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• 1996

Eight 2-day-old SPF Chickens were each inoculated Orally With 3 Sing1e dose Of 5 × 105 oocysts of Cryptosporinium boilevi. and immunoglobulin G (IgG) antibody responses were chronologically measured by indirect immunofluorescent antibody (IFA) assay. Anti-C. bcileyi IgG antibody levels remained high (1 : 106.67 to 1:512.00) for at least 4 months with 330 days of a detectable period. Ten days after the negative conversion, each chicken was re-challenged with 1 × 107 oocysts of the same species. Subsequent infection in 340-day-old individuals caused sudden elevated IgG antibody levels and the titer peaked on day 28 postchallenge inoculation (PCI), at 1:1.024 with a 65 days of detection period. Chickens in primary infection showed oocyst shedding profiles. but did not exhibit any oocyst shedding before or after experimental reinfection.

• Journal of the Korean Electrochemical Society
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• v.21 no.1
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• pp.6-11
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• 2018

For the high performance of the secondary battery to satisfy the demands in electronic and energy industries, it is necessary to develop more safe, environmentally friendly and economical electrode. Recently, lithium-sulfur batteries are receiving attention as next-generation secondary cells in terms of its remarkable theoretical capacity, energy density and environmental characteristics. However, they have not yet overcome a fading phenomenon due to the dissolving of the polysulfide. In this study, we intend to fabricate a battery using sulfur, a higher energy density than the other bipolar materials, as an improved secondary cell electrode material. The aim of the study is to improve battery performance with an optimal ratio of the cathode components; such as sulfur of active material and Super P of an electronic conductor.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.85-92
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• 2015

The 50 mole% HCl doped polyaniline(PAni) was synthesized by polymerization of aniline in the presence of hydrochloric acid and ammonium persulfate(APS) as dopant and oxidant, respectively. Then, conducting biodegradable cellulose acetate composite films were also prepared with PAni in acetone to find their applicability to antistatic packaging materials. The tensile strength of PCA05 film with 5 wt% of PAni was decreased by 27% from $377.1kg_f/cm^2$ for CA film itself to $275.2kg_f/cm^2$. Elongation was also decreased from 7.65% to 4.35%. Surface registance of $7.0{\times}10^9{\Omega}/sq$ could be achieved for the PCA containing 5 wt% of PAni. Therefore, this PCA05 film can be applied to antistatic package film for electronic board. In addition, decomposition temperature of these PCA films obtained by thermogravimetric analysis(TGA) was decreased with the amount of PAni in PCA films, and the final weight of char was directly proportional to PAni contents. From this thermal result we can calculate the content of PAni in unknown PCA films.