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        검색결과 28

        1.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The pitch-based activated carbons were prepared with KOH/KMnO4 as a multiple function activation agent to increase the specific capacitance of a supercapacitor electrode active material. And the porous structure and electrochemical properties of activated carbon were analyzed on varying amounts of KMnO4. KMnO4 was decomposed into K2O, MnO, and O2 at the activation temperature of KOH, and MnO was introduced to activated carbon. K2O/ O2 reacts with a surrounding pitch to generate micropores and forms a pathway that exposes MnO to the outside. It also affects to the specific surface area of activated carbon like KOH chemical activation. The enhanced specific surface area and introduced MnO in activated carbon led to a 28.9% increase in specific capacitance.
        4,000원
        2.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fibrous adsorbents, such as activated carbon fibers (ACF) have acknowledged advantages of rapid adsorption rate and ease of modification compared with granular and powdered adsorbents. Based on the surface modification of lyocell-based ACF, we observed different surface characteristics of ACF samples with variation in the mixing ratio and impregnation time of H3PO4, NaCl, and KMnO4 solution. For an engineering application, we also explored the adsorption characteristics of thusproduced ACF samples onto volatile organic compounds (VOCs). Isothermal adsorption experiments were performed using toluene and benzene as adsorbates. Results indicate that both physical and chemical surface properties have an effect on the adsorption of volatile organic compounds (VOCs).
        4,000원
        3.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A study on indigenous diatoms was carried out at 10 sites from May 2014 to December 2016 in marine and freshwater in Korea. Seventeen species of diatoms are new to Korea and they are divided into 3 classes, 4 subclasses, 10 orders, 14 families, and 16 genera. The nomenclatures, references, dimensions, specimens examined, local habitat, distribution in Korea, and photograph are reported here. Seventeen species found in marine, freshwater, and brackish water showed species-specific habitats.
        4,300원
        4.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report on the dispersion state of partially reduced graphene oxide (PRGO) in organic solvents, namely methyl ethyl ketone, ethyl acetate, methylene chloride, toluene, and xylene, by controlling the carbon to oxygen (C/O) atomic ratio of the PRGOs. A two-phase solvent exchange method is also proposed to transfer PRGO from water to an aprotic solvent, such as methyl ethyl ketone. We achieve relatively good dispersion in aprotic and non-polar solvents by controlling the C/O atomic ratio of the PRGOs and applying the two-phase solvent exchange method. There is an increase in the glass transition temperatures with the dispersion of PRGOs into amorphous polymers, in particular a 4.4°C increase for poly(methyl methacrylate) and 3.0°C increase for polycarbonate. Good dispersion of PRGO in a nonpolar polymer, such as linear low density polyethylene, is also obtained.
        4,000원
        5.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        예부선이 항행할 경우 부선의 회두운동으로 인하여 예선은 조종성능에 제한을 받기 때문에 부선의 회두운동을 감소시켜야 안전한 예항업무를 이행할 수 있다. 본 연구에서는 부선의 침로안정성을 향상시키기 위한 방안으로 부선의 회두운동에 영향을 미치는 항목들을 조사하기 위하여 수조실험을 실행하였다. 선수 형상에 따라 회두운동 특성이 다르게 나타나기 때문에 서로 다른 선수 형상을 지닌 부선 모델을 대상으로 스케그의 영향, 예인선속의 영향, 예인삭 길이의 영향, 브라이들의 영향에 대하여 종합적으로 분석하였다. 실험결과 스케그의 설치 위치에 의한 효과는 선수형상에 따라서 다르게 나타나고 있는 모습을 보여주고 있다. 부선의 회두운동은 부선에 연결된 예인삭의 길이가 길수록 부선의 회두가 작아짐을 알 수 있었다. 또한 예인삭만 연결한 상태보다 예인삭에 브라이들을 연결하는 것이 부선의 회두가 작아지며, 브라이들의 길이가 길어질수록 부선의 회두운동이 크게 작아짐을 알 수 있었다.
        4,000원
        15.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the effects of heat appli˗ cation on the immune activities of the human body. To exam, further˗ more, the immune effect from the healthy volunteer(male:15, female:15) by monitoring changes of immune substances such as various leukocytes[total white blood cell(WBC), eosinophil, neutrophil, basophil, monocyte, and lymphocyte], a comparative study with warm water immersion(40.8±0.3℃) and infrared(250W) was carried out. The plasma analysis showed that the count of white blood cell, eosinophil, and neutrophil were elevated in warm water immersion- or infrared˗ stimulated group compared with control group. However, the count of basophil was decreased in both warm water immersion- and infrared-stimulated group than control group. Therefore, these results suggest that the thermostimulation improved immune activity.
        4,000원
        18.
        2017.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We studied the hour-lines of six extant Yangcheon-cheoks in Korea. To find whether Yangcheon-cheok was used in the whole area of Korea, we calculated the length of shadows of Yangcheon-cheok on the Korean Peninsula, Nanjing and Beijing as well as Hanyang (Seoul), according to 24 solar terms. Comparing the length of shadows with hour-lines of those relics, we could find that Yangcheon-cheok was suitable for use at limited times (from 9:00 to 15:00) during the year. Also, this sundial is more appropriate for use at low latitudes than high ones. Among existing relics, that of Seoul Museum of History made with porcelain was much more suitable to use at Hanyang and its higher latitude. Lee’s collection was also suitable to use at Nanjing. It is certain that Yangcheon-cheok was a portable sundial which could be used from nine to fifteen of clock all the year around except for the winter season.
        19.
        2016.06 KCI 등재 서비스 종료(열람 제한)
        This study describes results on sexual maturation and characteristics of natural spawned eggs to develop a method for the production of stable, healthy fertilized eggs from captive-reared yellowtail kingfish, Seriola lalandi. A total of 59 yellowtail kingfish were captured off the coast of Jeju Island, after which the broodstock was cultured in indoor culture tank (100 m3) until they were 6.1–14.9 kg in body weight. As part of the rearing management for induced sex maturation, the intensity of illumination was maintained at 130 lux. The photoperiod (light/dark; L/D) was set to a 12 L/12 D from October 2013 to January 2014, and 15 L/9 D from February 2014 to June 2014. Feeds comprised mainly EP (Extruded Pellets), with squid cuttlefish added for improvement of egg quality, and was given from April to June 2014. The first spawning of yellowtail kingfish occurred in May 3, 2014, at a water temperature of 17.0°C. Spawning continued until June 12, 2014, with the water temperature set at 20.5°C. Time of spawning was 26 times at this period. The total number of eggs that spawned during the spawning period was 4,449×103. The buoyant rate of spawning eggs and fertilization rate of buoyant eggs during the spawned period were 76.1% and 100%, respectively. The diameters of the egg and oil globule were 1.388 ± 0.041 mm and 0.378 ± 0.029 mm, respectively, which was higher in early eggs than in those from late during the spawned period.
        20.
        2015.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We investigated the six remaining Yang-cheon-cheoks (量天尺), which were first described in the Veritable Record of King Sukjong (肅宗實錄). These woodblock sundials from Korea are structurally very similar to a Gyupyo (圭表, gnomon) or an altitude sundial and are light, compact, and portable. The front side of a Yang-cheon-cheok has two holes for styluses and several hour-lines. We compared the intervals of the hour-lines from the originating point of the stylus placement on all Yang-cheon-cheoks and found that two of the relics had the same hour-lines using the standard of the unit of 1 chon (寸). These two were actually the same sundial although the physical size was different. In spite of the lack of time accuracy, we hypothesize that various-sized Yang-cheon-cheoks were made and widely distributed throughout the public in the late Joseon Dynasty.
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