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        검색결과 422

        83.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The carbon anode material for lithium-ion battery was prepared by pyrolysis fuel oil and waste polyethylene terephthalate (PET) additive. The pitch was synthesized as a medium material for carbon anode by heat treatment. The waste PET additive improved the softening point and thermal stability of the pitch. La and Lc of the anode material (heat-treated pitch) increased at higher treatment temperature but decreased by waste PET additive. The electric capacity was evaluated based on effects of defective cavity and developed graphite interlayer, respectively. When the La and Lc of the anode material decreased, the electric capacity by cavity increased based on defective graphite structure. Therefore, the addition of waste PET causes the improved capacity by the cavity. The anode material which has a high efficiency (over 95%) and C-rate (95%, 2 C/0.1 C) was obtained by controlling the process of heat treatment and PET addition. The mechanism of lithium-ion insertion was discussed based on effects of defective cavity and developed graphite interlayer.
        4,000원
        85.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Evaluating the operational efficiency of electric vehicle charging stations (EVCSs) is important to understand charging network evolution and the charging behavior of electric vehicle users. However, aggregation of efficiency performance metrics poses a significant challenge to practitioners and researchers. In general, the operational efficiency of EVCSs can be measured as a complicated function of various factors with multiple criteria. Such a complex aspect of managing EVCSs becomes one of the challenging issues to measure their operational efficiency. Considering the difficulty in the efficiency measurement, this paper suggests a way to measure the operational efficiency of EVCSs based on data envelopment analysis (DEA). The DEA model is formulated as constant returns of output-oriented model with five types of inputs, four of them are the numbers of floating population and nearby charging stations, distance of nearby charging stations and traffic volume as desirable inputs and the other is the traffic speed in congestion as undesirable one. Meanwhile, the output is given by the charging frequency of EVCSs in a day. Using real-world data obtained from reliable sources, we suggest operational efficiencies of EVCSs in Seoul and discuss implications on the development of electric vehicle charging network. The result of efficiency measurement shows that most of EVCSs in Seoul are inefficient, while some districts (Nowon-gu, Dongdaemun-gu, Dongjak-gu, Songpa-gu, Guro-gu) have relatively more efficient EVCSs than the others.
        4,000원
        86.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        전기장에 의해 생성 된 진공 분극은 양자장에서 가상 전자-양전자 쌍의 재배열을 만든다. 그러나 정지 전하가 다른 장소로 이동할 때, 정지 전하에 의해 생성된 전기장은 사라질 것이다. 이때, 정지 전하에 의해 분극화된 가상 전자-양전자 쌍들은 같이 소멸된다. 가상 전자-양전자의 소멸 과정에서 가상 광자가 생성되는데, 이때 만들어지는 가상 광자들은 양자 전기 역학에서 자기력을 매개하는 광자가 된다. 이로 인하여, 전하의 이동은 자기장을 발생시키고, 전기장의 변화가 자기장을 생성하게 하는 원인이 된다.
        3,000원
        87.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the flow analyses were carried out on the electric train models with three kinds of mounting materials installed at the front part of train. By examining the results of flow rate and pressure, It was investigated which type of design should be designed to be more efficient in high-speed operation. The three types of models are set as models a, b and c, and each has its own shape. For all models, the wind speed was set at 110 km/h, the most common driving speed for wide-area electric trains. In the case of the model a, it was good at cutting the wind flow as a round shape when viewed from the top. But from the side, it showed a vortex forming in the upper corner. To the contrary, the model b, which has a wedge-shaped side, could be seen from the top as a result of a vortex. Finally, in the case of model c combined with models a and b, the least vortex, front pressure, and resistance forces were shown by selecting the flow advantages of models a and b. By utilizing this study result, the flow velocity and pressure are investigated without flow experiment by shape of the front part of electric train, and the flow capacity can be seen.
        4,000원
        89.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to the development of the industry, the importance of injection molded products is increasing in the fields of electricity, electricity, automobiles, etc. Through this experiment, the weight change of molded products according to the injection speed change during injection molding was investigated. As a result of the experiment, a statistical program was used to confirm that the pi control method produced about 69.2% more weight deviation than the dpi method and to adopt the null hypothesis that the p-value was less than 0.05 Injection speed affected the molded product.
        4,000원
        90.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, at-home workouts, which allows people to exercise easily and comfortably at home without going to the gym, has been in the spotlight. Accordingly, a lot of household equipment is produced, but weight exercise equipment is limited in use at home because of its heavy weight or volume. Therefore, this paper proposes a new form of exercise equipment that can be used at home by transforming the exercise equipment used in the fitness center. The proposed mechanism replaces the weight part of the strength exercise device, which is the key to weight control, with an electric motor. Three major muscle exercise instruments (long pull machine, curl cable machine, and let down machine) were analyzed by dynamic analysis using a multipurpose dynamic program (DAFUL). This shows that the proposed equipment can perform various sports. Therefore, the proposed mechanism is expected to be applicable at home, and this study is expected to be rapidly mass-produced by emphasizing practicality.
        4,000원
        91.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the deformation, equivalent stress and strain energy were analyzed on the electric kick board emerging as a new means of transportation at the accident of a front collision according to each shape were analyzed. The largest part deformation happened at the handle, and the board part where the person’s feet was placed was seen to become weak. The equivalent stress was most visible at the board section, unlike the deformation results. In particular, the deformation and stress of model A which has a long and thin neck, have occurred greatly. Therefore, the longer the neck, the greater the deformation and stress occur. Among all models, the deformation and stress were the smallest at model C. As model A has a particularly thinner neck and board connection part, a large strain energy appeared. Therefore, it is considered that the connection needs to be reinforced thickly and firmly. On the study result, the thicker the board part of the electric kick board and the lower the body of the vehicle, the safer it is. The results of this study can be effectively applied to investigate the values of stresses and deformations, and strain energies through structural analysis without the fracture test at the front collision according to the shape of electric kick board.
        4,000원
        92.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 필립 케이 딕의 과학소설『안드로이드들은 전기 양을 꿈꾸는가?』와『유빅』에서 나타난 SF적 상상력과 종교적 비전을 고찰하는데 있다. 딕은『안드로이드』와『유빅』에서 우리의 세계가 고도의 과학기술과 자본주의로 인해 인간의 탐욕과 불안으로 가득 찬 엔트로피적 세계임을 비판하면서 이것을 해결하기 위한 대안으로 ‘머서주의’와 ‘유빅’이라는 종교적 비전을 제시한다. 딕은 작품에서 ‘머서주의’를 통해 인간 본성의 선과 악을 인정하고 인간 존재의 불완전함을 받아들이고 극복해야 한다고 주장한다. 감정이입을 기반으로 하는 머서주의는 선과 악의 극단적인 대립을 강조하는 전통적 종교의 경직된 사고를 해체하고 자신과 타자의 경험 공유를 통해 자기 구원을 선언할 수 있음 을 재현한다. 또한 로고스로 확인되는 유빅을 통해 구원의 가능성을 제시한다. 이를 통해 딕은 신성은 거룩한 교회나 성소에만 존재하는 것이 아닌 주변과 일상의 삶에서 발견될 수 있음을 이야기하며 종교의 의미가 단순히 믿음의 문제 뿐만 아니라 인간 존재와 공동체적 가치를 실현하는 궁극적인 신념임을 제시한다.
        5,800원
        99.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Foot drop is a common symptom after stroke and causes walking disorders. Therefore, its proper treatment is important for improving the walking ability of patients with foot drop. Objective: This study aimed to investigate the effects of electrostimulation during walking on the walking ability of patients with foot drop after stroke. Design: Quasi-experial study. Methods: The study enrolled 18 patients with foot drop after stroke. All subjects were assigned to the experimental or control group. The experimental group underwent electric stimulation during walking, while the control group used ankle foot orthoses. Both groups received treatment 20 minutes a day 5 times a week for 4 weeks. Outcome measures were assessed for walking and balance ability using the 10-m walking test (10MWT), 6-min walking test (6MWT), and Timed Up and Go test (TUG) Results: After the intervention, both groups showed significant improvements in 6MWT and TUG results. However, the experimental group showed significantly better improvement on all tests than the control group. Conclusion: The foot drop stimulator effectively improved the walking and balance ability of patients with foot drop after stroke.
        3,000원
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