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        검색결과 247

        27.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pyrolysis fuel oil (PFO) is used for the manufacturing of high-purity pitch for carbon precursor due to its high carbon content, high aromaticity, and low heterogeneous element and impurity content. Pitch is commonly classified with its softening point, which is most considerable physical property affecting to various characteristics of the carbon materials based on pitch, such as electrical and thermal conductivity, mechanical strength, and pore property. Hence, the softening point should be controlled to apply pitch to produce various carbon materials for different applications. Previous studies introduce reforming process under high pressure and two step heat treatment for the synthesis of pitch with high softening point from PFO. These methods lead to a high process cost; therefore, it is necessary to develop a process to synthesize the pitch with high softening point by using energy effective process at a low temperature. In this study, waste polyethylene terephthalate (PET) was added to control the softening point of PFO-based pitch. The pitch synthesized by the heat treatment with the addition of PET showed the softening point higher than that of the pitch synthesized with only PFO. The softening point of PFObased pitch synthesized at 420 °C was 138.3 °C, while that of the pitch synthesized by adding PET under the same process conditions was 342.8 °C. It is proposed that the effect of the PET addition on the increase in the softening point was due to the radicals generated from thermal degradation of PET. The radicals from PET react with the PFO molecules to promote the polymerization and finally increase the molecular weight and softening point of the pitch. In addition, activated carbon was prepared by using the pitch synthesized by adding PET, and the results showed that the specific surface area of the activated carbon increased by the addition of PET. It is expected that the pitch synthesis method with PET addition significantly contributes to the manufacture of pitch and activated carbon.
        4,000원
        28.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the effects of micro- (crystallinity) and macro (orientation)-crystalline properties of graphite on the initial efficiency, discharge capacity, and rate performance of anodic materials. Needle coke and regular coke were selected as raw materials and pulverized to 2–25 μm to determine the effects of crystalline properties on particle shape after pulverization. Needle coke with outstanding crystallinity had high initial efficiency, and smaller particles with larger specific surface areas saw increased irreversible capacity due to the formation of SEI layers. Because of cavities existing between crystals, the poorer the crystalline properties were, the greater the capacity of the lithium ions increased. As such, regular coke had a 30 mAh/g higher discharge capacity than that of needle coke. Rate performance was more affected by particle size than by crystalline structure, and was the highest at a particle distribution of 10–15 μm.
        4,000원
        34.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이탈리안벌인 A, C, F계통과 코카시안벌인 D, V계통을 2005년부터 2007년까지 국내에서 수집하였다. 수집한 계통은 육종을 위해 격리 된 섬에서 근친교배를 통해 순계로 분리하였다. 이 연구는 꿀, 로열젤리 다수확계통 선발에 있어 개체군 선발과 육종 효율을 높이기 위해 수행되 었다. 23 개의 형태학적 특성을 평가하고 두 아종의 기존 데이터와 비교한 결과, 이탈리안벌 순계계통은 코카시안벌 순계 계통과 달리8개의 특성이 기존의 이탈리안벌과 유사해 더 많은 특성이 보존되고 있음을 알 수 있었다. 또한 국내에서 유지되고 있는 순계들은 타 지역의 동일 계통과 차 이를 보여 분리된 순계의 형태적인 특징이 확인되었다.
        4,300원
        36.
        2020.11 구독 인증기관 무료, 개인회원 유료
        Prior social robotics research has shown that robot design influences if people perceive a robot as friendly, trustworthy, or safe (Castro-Gonzalez et al., 2016; Rosenthal-Von Der Pütten & Krämer, 2014). Meanwhile, recent conceptual work has suggested that social robots will increasingly be used in the front line of service encounters (Gonzalez-Jimenez, 2018; Van doorn et al., 2017). According to The International Journal of Social Robotics social robots are robots that can communicate and interact with humans, among themselves, and with the environment, within the cultural and social structure assigned to its role. Real examples of the inclusion of these robots in retail settings already exist. For instance, some retailers use Softbank´s robot Pepper to greet and inform customers. Social robots such as Pepper can use their sensors and cameras to interpret customer reactions and adapt accordingly. Moreover, the robot can even make product recommendations based on the assessed customer´s mood, age, gender and, if available, purchase history (McKenna, 2018). Not surprisingly, there is a vast market potential associated with these robots, which is expected to grow to 87 billion by 2025 (BCG, 2017).
        3,000원
        37.
        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
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