검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 35

        2.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Biomass-derived porous carbon is an excellent scientific and technologically interesting material for supercapacitor applications. In this study, we developed biomass-derived nitrogen-doped porous carbon nanosheets (BDPCNS) from cedar cone biomass using a simple KOH activation and pyrolysis method. The BDPCNS was effectively modified at different temperatures of 600 °C, 700 °C, and 800 ℃ under similar conditions. The as-prepared BDPCNS-700 electrode exhibited a high BET surface area of 2883 m2 g− 1 and a total pore volume of 1.26 cm3 g− 1. Additionally, BDPCNS-700 had the highest electrical conductivity (11.03 cm− 1) and highest N-doped content among the different electrode materials. The BDPCNS-700 electrode attained a specific capacitance of 290 F g− 1 at a current density of 1 A g− 1 in a 3 M KOH electrolyte and an excellent longterm electrochemical cycling stability of 93.4% over 1000 cycles. Moreover, the BDPCNS-700 electrode had an excellent energy density (40.27 Wh kg− 1) vs power density (208.19 W kg− 1). These findings indicate that BDPCNS with large surface areas are promising electrode materials for supercapacitors and energy storage systems.
        4,300원
        3.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        원자전달 라디칼 중합을 이용하여 poly(epichlorohydrine) (PECH)를 주사슬로 한 양친성 가지형 공중합체를 합성하였다. PECH로부터 poly(methyl methacrylate)(PMMA) 및 poly(butyl methacrylate)(PBMA)의 가지형 중합이 성공적임을 1H NMR과 FT-IR분석을 통해 확인하였다. 합성한 가지형 공중합체에 KI나 LiI 염을 도입하였을 때, ether 신축진동 피크가 낮은 wavenumber영역으로 이동하였으며, 이는 배위결합 상호작용 때문이다. PECH-g-PBMA 복합체의 이온 전도도는 PECH-g-PMMA 복합체에 비해 항상 높게 나타났는데, 이는 고무상인 PBMA 사슬의 높은 이동성으로부터 기인한 것으로 확인되었다. 최고 이온전도도 값은 질량비 10 wt%의 KI가 도입된 PECH-g-PBMA 전해질체에서 2.7 × 10 -5 S/cm로 나타났다.
        4,000원
        5.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Poly(vinyl chloride) (PVC) 주사슬과 poly(hydroxyethyl acrylate) (PHEA) 곁사슬로 구성된 가지형 공중합체를 원자전달라디칼 중합을 통해 합성하였다. PVC의 2차 염소원자의 직접적인 개시반응에 의해 친수성인 PHEA 단량체를 그래프팅시켰다. 이렇게 합성된 PVC-g-PHEA을 술포석시닉산(SA)를 사용하여 가교시켰으며, 이는 가지형 공중합체의 -OH 그룹과 SA의 -COOH와의 에스테르 반응임을 FT-IR 분광법을 이용하여 분석하였다. 이온교환능(IEC)은 SA 함량이 증가함에 따라 계속하여 증가하여 0.87 meq/g까지 도달하였고, 이는 전해질막에 이온 그룹수가 증가하기 때문이다. 하지만, 함수 율은 SA 함량이 20 wt%까지는 증가하다 그 이상에서는 감소하였다. 또한 수소 이온 전도도도 SA 함량에 따라 증가하여 20 wt% SA 농도에서 0.025 S/cm의 최대값을 나타내었고, 이는 SA 함량이 증가함에 따라 이온 그룹의 수가 증가하는 효과와 가교가 증가하는 효과가 서로 경쟁적으로 일어나기 때문으로 사료된다.
        4,000원
        6.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        폴리스티렌-폴리히드록시에틸 아크릴레이트(PS-b-PHEA) 디블록 공중합체와 폴리비닐알콜(PVA)을 1 : 1 무게비로 블렌딩하여 수소 이온 전도성 가교형 고분자 전해질막을 개발하였다. 특히 술포석시닉산(SA)를 사용하여 디블록 공중합체의 PHEA 블록과 PVA와 가교반응을 시켰고, 이를 FT-IR 분광법을 이용하여 분석하였다. 이온교환능(IEC)은 SA 함량이 증가함에 따라 계속하여 증가하여 0.95 meq/g까지 도달하였고, 이는 전해질막에 이온 그룹수가 증가하기 때문이다. 하지만, 함수율은 SA 함량이 20 wt%까지는 증가하다 그 이상에서는 감소하였다. 또한 수소 이온 전도도도 SA 함량에 따라 증가하여 20 wt% SA농도에서 0.024 S/cm의 최대값을 나타내었다. 함수율과 수소이온전도도의 이러한 경향은 SA 함량이 증가함에 따라 이온 그룹의 수가 증가하는 효과와 가교가 증가하는 효과가 서로 경쟁적으로 일어나기 때문으로 생각된다.
        4,000원
        7.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        폴리비닐리덴플로라이드(PVDF) 지지체 위에 빗살모양의 술폰화된 공중합체를 코팅하여 나노 분리막을 제조하였다. 빗살모양의 공중합체는 원자전달 라디칼 중합법(ATRP)에 의해 제조하였으며, 폴리비닐클로라이드의 주사슬과 폴리스티렌 술폰산(PSSA)의 곁사슬로 구성되어 있다. 핵자기 공명법(1 H-NMR), FT-IR분광학 그리고 WAXS 분석법에 의해 공중합체가 성공적으로 합성되었음을 확인하였다 PVC-g-PSSA로 구성된 복합 나노 분리막은 PSSA의 함량이 증가함에 따라 플럭스와 배제율 모두 증가하였다. 이러한 성능 향상은 분리막의 술폰산의 함량의 증가로써 설명할 수 있다. PSSA가 71wt%첨가된 나노 복합막의 배제율은 Na2SO4 88%, NaCl 33%을 나타내었고, 플럭스는 Na2SO4 26, NaCl 34 L/m 2 h을 각각 나타내었다.
        4,000원
        8.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        폴리스티렌-블록-폴리히드록에틸 메타크릴레이트(PS-b-PHEMA), 술포석시닉산(SA), 인텅스텐산(PWA)으로 구성된 수소 이온 전도성 나노복합 고분자 전해질막을 제조하였다. 폴리히드록에틸 메타크릴레이트(PHEMA) 블록의 히드록실그룹(-OH)와 술포석시닉산(SA)의 -COOH 그룹과의 에스테르 반응에 의하여 전해질막을 가교시켰다. 폴리헤테로산(PWA)을 도입했을 때, SO3 - 그룹의 신축 밴드가 1187 cm -1에서 1158 cm -1로 낮아졌으며, 이는 PWA 입자가 전해질막의 술폰산 그룹과 상호작용함을 나타낸다. PWA 함량이 30wt%가 되었을 때, 상온 전도도는 0.045에서 0.062S/cm로 증가되었으며, 이는 PWA 입자의 고유 전도도 특성과 전해질막의 술폰산기의 산도가 증가했기 때문이다. 또한 30wt%를 함유한 복합 전해질막은 100℃에서는 최대 0.126 S/cm의 수소 이온 전도도를 나타내었다 PWA가 첨가됨에 따라 복합 전해질막의 열적특성 또한 증가하였다.
        4,000원
        9.
        2016.10 서비스 종료(열람 제한)
        Background : Malonyl ginsenoside content of the Panax ginseng is known to account for 35% to 60% of total ginsenosides content. However, its distribution by ginseng part has not been studied. In this study, four kinds of malonyl ginsenosides were compared in Korean white ginseng part using the purified malonyl ginsenoside standards in our laboratory. Methods and Results : White ginseng was prepared by the air drying (50℃, 48h) or freeze drying (-70℃, 48h) methods form 4-year-old ginseng. Malonyl ginsenoside content in total ginsenosides were similar in air dried and freeze dried white ginseng, 58% and 62%, respectively. Therefore, malonyl ginsenoside contents in main, lateral, and fine root, and in the main root without skin and skin of main root prepared by freeze dried method were compared. Malonyl ginsenosides (m-Rb1, m-Rb2, m-Rc and m-Rd) and total ginsenosides (Rg1, Re, Rf, Rb1, Rc, Rb2, Rb3, Rd, m-Rb1, m-Rb2, m-Rc and m-Rd) were 6.75 and 14.15 mg/g in main root, 14.15 and 26.35 mg/g in lateral root, 46.95 and 84.15 mg/g in fine root. Malonyl ginsenoside contents in skin of main root was 20.08 mg/g, while its contents of the main root without skin was 2.58 mg/g. Conclusion : As a result, the parts each air drying the sample was confirmed that the ratio of the distribution of malonyl ginsenoside (main root : lateral : fine root = 18.7 : 11.1 : 16.2), and distribution ratio of main root, skin of main root, lateral, skin of lateral was found to be (12.2: 14.6 14.3: 3.7). Malonyl ginsenoside content was the highest in fine root, compared to the main or lateral root. Malonyl ginsenoside contents in skin of root was higher than those of the main root without skin. These results is expected to help establish an efficient extraction and standardization. Malonyl ginsenoside analysis of White ginseng using HPLC expects that the standardization process can be established.
        10.
        2015.07 서비스 종료(열람 제한)
        Rice is a staple food crop for more than half of the world population. Severe losses of rice production was caused by various environmental conditions such as cold, heat and flooding annually. Rice is a highly sensitive to low temperature below 15-20 ℃ because of originating from tropical or subtropical climates. Especially, seedling of rice is easily damaged to low temperature and result in seedling yellowing, growth retardation, reduced tillering and yield losses at last. We used a recombinant inbreeding lines (RIL) population of 384 individuals derived from a cross between Hanareum 2, a highly cold sensitive variety and Unkwang, a cold tolerant variety for molecular mapping of QTLs related to cold tolerance. Seedling discoloration of each lines and parents caused by cold response were investigated in field condition after transplanting. And leaf samples of RIL population were collected for evaluation of chlorophyll content using 80% acetone extraction. The seedling of each lines and parents was subjected to low temperate by 5~13 ℃ during 14 days. The cold recovery score (CRS) of RILs was recorded after 4 days recovery period according to standard evaluation system (SES, IRRI). Total of eight QTLs were detected on chromosome 1, 7, 8, 10, 11 and 12 using cold tolerance traits, chlorophyll content, seedling discoloration and cold recovery score in 384 RILs. The qCRS12, which detected on chromosome 12 between two flanking markers id12002113, id12002563 (1.1 Mbp) showed 25 LOD score with 26% of phenotypic variation of cold recovery score in RILs population. The positive allele contributing to cold tolerance came from the cold tolerant parent Unkwang. The result may provide useful information for a marker-assisted breeding program to improve cold tolerant in rice.
        11.
        2007.09 KCI 등재 서비스 종료(열람 제한)
        A new black seed coat soybean variety, “Socheong” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Socheong was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Peking which was tolerant to lodging and with small seed size. The preliminary, advanced and regional yield trials for evaluation and selection of this variety were carried out from 2002 to 2006. It has determinate growth habit, white flower, brown pubescence, brown pod color, black seed coat, green cotyledon, elongated flattened seed shape, oval leaf shape and small seed size (15.7 grams per 100 seeds), and it was 3 days later in maturity than the check cultivar Cheongjakong. Socheong was higher, in the seed quality of sucrose and total sugar contents (6.8 and 8.2%) and isoflavone contents (1,754 ㎍/g) than the check cultivar. Futhermore, it has good characteristics for mechanical harvest, such as lodging tolerance, pod shattering and stem diameter. It also has been identified to have resistance to soybean mosaic virus symptom which was the troublesome soybean diseases. The average yield of Socheong was 2.21 ton per hectare in the regional yield trials carried out in four locations of Korea among seven locations from 2004 to 2006, which was 5 percent lower than the check cultivar Cheongjakong.
        12.
        2007.09 KCI 등재 서비스 종료(열람 제한)
        A new black seed coat soybean cultivar, “Heugmi” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Heugmi was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Milyang 68, which was middle maturing, resistant to lodging and SMV and with middle seed size and yellow cotyledon. The preliminary, advanced and regional yield trials for evaluation and selection of this cultivar were carried out from 2001 to 2006. It has determinate growth habit, purple flower, brown pubescence, black pod color, black seed coat, green cotyledon, spherical seed shape, oval leaf shape and middle seed size (24.8 grams per 100 seeds), and it was 2 days earlier in maturity than the check cultivar Cheongjakong. Heugmi was better in the seed quality of crude protein contents, sucrose and total sugar contents than the check cultivar. It also has been identified to have resistance to SMV which was the troublesome soybean diseases. The average yield of Heugmi was 2.53 ton per hectare in the regional yield trials carried out in seven locations of Korea from 2004 to 2006, which was 8 percent higher than the check cultivar Cheongjakong.
        1 2