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        검색결과 376

        122.
        2015.11 구독 인증기관·개인회원 무료
        The proton exchange membrane fuel cells(PEMFCs) have been noticed as the promising power sources. One of the important components in PEMFC is the proton exchange membranes(PEMs). Recently various materials for PEMs have been investigated for fuel cell applications. Sulfonated aromatic hydrocarbon-based multiblock copolymers have drawn much interest due to their well-defined phase separation between hydrophilic and hydrophobic blocks. In our group, multiblock copolymers based on highly sulfonated poly(fluorenyl ether sulfone)s were developed as highly conductive and stable polymer electrolyte membranes. We report herein the investigation of the influence of phase separation and properties by block length of the corresponding membranes.
        123.
        2015.11 구독 인증기관·개인회원 무료
        In the present work, a new synthesis method has been reported for preparing high-quality NaA zeolite membrane. The present method involves pressure-driven hydrothermal gel coating method(HGCM) on seeded α-alumina support surface having pores of 0.1 and 0.7μm diameter before the secondary growth process. The experimental data revealed that the high-pressure injection of hydrothermal gel solution on α-alumina support surface helped in the pore filling and thin layer coating of gel particles, which promoted the formation of uniform, defect free, and dense zeolite layer. Pervaporative dehydration experiments were conducted for 50 wt.% ethanol-water mixture at 343K. The NaA zeolite membrane, which was prepared by HGCM process on the 0.7μm support, showed that the high total flux was 4.7 kg m-2h-1 and separation factor was more than >1000.
        124.
        2015.10 구독 인증기관·개인회원 무료
        Saturnia (Rinaca) jonasii Butler, 1877 is distributed in Japan, including Tsushima Island and Taiwan, whereas S. boisduvalii Eversmann, 1846 is distributed in northern areas, such as China, Russia, and South Korea. In the present study we found that the specimens from Mt. Hallasan on Jejudo, a southern remote offshore island, were S. jonasii, rather than S. boisduvalii based on morphology, DNA barcode, and nuclear elongation factor 1 alpha (EF-1α) sequences. The major morphological differences between the two species included the shape of wing pattern elements of fore- and hindwings and male and female genitalia. A DNA barcode analysis of the sequences of the Jejudo specimens and S. boisduvalii, along with those of Saturnia species obtained from a public database showed a minimum sequence divergence of 4.26% (28 bp). A phylogenetic analysis also showed clustering of the Jejudo specimens with S. jonasii, separating S. boisduvalii (Bayesian posterior probability = 0.99). The EF-1α-based sequence and phylogenetic analyses of the two species from Jejudo Island and the Korean mainland showed the uniqueness of the Jejudo specimens from S. boisduvalii collected on the Korean mainland, indicating distribution of S. jonasii on Jejudo Island in South Korea, instead of S. boisduvalii.
        125.
        2015.10 구독 인증기관·개인회원 무료
        Kentrochrysalis streckeri Staudinger, 1880 is distributed in Russia, Mongolia, China, and North Korea, whereas K. consimilis Rothschild & Jordan, 1903 has been known to occur South Korea and Japan. In the present study we found that the specimens from South Korea were K. streckeri, rather than K. consimilis based on morphology, DNA barcode, and nuclear elongation factor 1 alpha (EF-1α) sequences. The major morphological differences between K. streckeri and K. consimilis include the shape of wing pattern elements of fore- and hindwings and male and female genitalia. A DNA barcode analysis of the South Korean specimens and K. streckeri originated from Russia showed a maximum sequence divergence of only 0.659% (four bp), whereas the barcoding sequence of K. consimilis sequenced in this study and GenBank-registered sequence (JN678086), both of which originated from Japan showed the minimum sequence divergence of 2.965% (18 bp), indicating that the Korean specimens are, in fact, K. streckeri, instead of wrongly known K. consimilis. Phylogenetic analyses both by Bayesian Inference and maximum likelihood methods well supported the monophyly of South Korean specimens and Russian K. streckeri, excluding K. consimilis. The EF-1α-based sequence and phylogenetic analyses of the two species also supported the data from DNA barcode, indicating distribution of K. streckeri in South Korea, instead of K. consimilis.
        126.
        2015.10 구독 인증기관·개인회원 무료
        The genus Phyllocnistis belongs to the family Gracillariidae including 85 described species in the world (De Prins and De Prins 2005). The genus has been placed under the family Phyllocnistidae, which is now the subfamily of the family Gracillariidae. In Korea, only one species of the family, Phyllocnistis citrella Stainton has been listed for the first time by Ko (1969) without the taxonomic information. It was first reported by Heppner (1993) from North America, and it has become to the major pest of Rutaceae, especially damaging on the genus Citrus spp. It has been called as CLM (citrus leafminer) in the world. This study was carried out to identify and monitor CLM easily and correctly with providing the genitalic structures and DNA barcode which is now one of the major insect pest on citrus farm.
        127.
        2015.10 구독 인증기관·개인회원 무료
        Sensory system of insect is important for their fitness in the environment. Riptortus pedestris (Hemiptera: Alydidae) is a major pest of bean plants and some fruit trees in Korea, Japan, China, and South Asian countries. This study was conducted to investigate morphology and distribution of antennal sensilla of R. pedestris, using scanning electron microscopy. Antennae of R. pedestris was 11 and 9.84 mm in length in male and female, respectively, and consists of four segments; scape, pedicel, flagellum 1 and 2 (F1 and F2). Five types of sensilla (s.) trichodea, four types of s. basiconica, two types of s. chaetica, and one type of s. coeloconica were preliminary identified in both sexes of adult R. pedestris, based on their size, shape, presence of socket and surface structure. Three types of trichoid sensilla, four types of basiconic sensilla, one type of chaetic sensilla and coeloconic sensilla had numerous pores along the surface of the sensilla, suggesting their olfactory function. Eight types of sensilla (3 trichoid, 2 basiconic, a chaetic and a coeloconic) showed a distinct socket structure at the base of each sensillum. Different types of sensilla showed different distribution along the antennal segments. Two types of trichoid sensilla and two types of basiconic sensilla were distributed on scape, pedicel and F1 flagella subsegment. However, the distribution of eight other types of sensilla was limited to one of two flagella subsegments.
        128.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        We investigated the galaxy morphology of 6 Abell clusters at z = 0:0784 - 0:145 based on deep images obtained using MegaCam on the CFHT. For hundreds of galaxies in our data, we classified their mor- phology based on criteria related to secular or merger related evolution. We found that the morphological mixture of galaxies varies considerably from cluster to cluster. This article contains a general description of our deep imaging campaign and preliminary results for galaxy morphologies in cluster environments.
        129.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We prepare a catalog of the morphological types of 5840 galaxies within z = 0.01. We determine the morphological types by visual inspection using color images from the Sloan Digital Sky Survey (SDSS) DR7. The majority of the sample galaxies are SDSS spectroscopic target galaxies, but we add  900 galaxies whose redshifts are available in the NASA Extra Galactic Database (NED). The fraction of elliptical and lenticular galaxies is ~ 0.06 while spiral galaxies comprise ~ 30% of the sample with a bar fraction of ~ 0.6. About half of sample are dwarf galaxies of which ~ 35% are dwarf elliptical-like galaxies. There is a strong correlation between the morphological types and luminosities of the galaxies, i.e., high luminosities in the early type galaxies and low luminosity in the late type galaxies. The mean luminosity of dwarf elliptical-like galaxies is similar to that of irregular galaxies.
        3,000원
        130.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        Star formation activities dominate the evolution of galaxies. Elliptical galaxies are believed to be old galaxies in the Hubble sequence, and elliptical galaxies at different evolution epochs might have different star formation activities and/or morphologies. We investigate the connection between star formation rates and the morphology of elliptical galaxies. With the Sloan Digital Sky Survey (SDSS) and the Galaxy Zoo, we select a sample of elliptical galaxies by morphology and consider their infrared emission as an index of star formation rate to study the relation between the star formation rates and their morphological properties, such as ellipticities. In addition, we select some nearby spiral galaxies with very low MIR emission to probe the mechanisms of these red spiral galaxies. We display our preliminary results and discuss their implication on the evolution of galaxies in this poster.
        131.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        개맥문동(Liriope spicata (Thunb.))이 검정주머니나방(Mahasena aurea (Butler))의 새로운 기주식물로 처음으로 확인되었기에 보고한다. 또한 본 연구를 통해 본 종의 유충과 암컷이 우리나라에서는 처음으로 채집되었다. 이들의 암컷과 수컷에 대한 외부형태적 특징을 재기재함과 동시에 수컷생식기, 성충, 애벌레, 번데기 등의 특징을 도해하여 제시하였다.
        4,000원
        132.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The taxonomic importance of pollen morphologyin family Malvaceae had long been acknowledged as it pro-vides the basis for palynological and phylogenetic analysis.In present study, pollen morphological characteristics of var-ious Hibiscus syriacus cultivars were examined. The objec-tive of this study was to provide comprehensive evidence onpollen morphology and to determine pollen morphologicaldiversity in cultivars of H. syriacus that would be useful forplant taxonomy and classification. To get a clear insights ofthe pollen morphology, scanning electron microscopy (SEM)was carried out. It has been recorded that the pollen diam-eter of 16 cultivars of H. syriacus ranges from 108.81 to172.15 •Ïm. The maximum pollen size was reported fromthe cultivar ‘Chongdansim’ followed by the cultivar ‘Paedal’.The maximum spine exine length was reported from‘Jabae’ (25.29µm) followed by ‘Collie mullens’ (23.25µm),whereas the minimum value was recorded from ‘Paedal’(8.16µm). It is apparent from this study that pollen morphol-ogy of various H. syriacus cultivars was fairly uniform, andin almost all studied cultivars the pollen shape was spheroi-dal. The spines were present in all studied cultivars and var-ied considerably among the cultivars. The pollen spinefeatures presented notable variations which were of greatsignificance at both specific and generic levels, and hasalso been helpful in understanding the process of spine evo-lution within H. syriacus. The maximum distance betweenspines was observed from cultivar ‘Gyewolhyang’ that haddistance of 45.03µm. The morphological characteristics ofpollen studied in this study could be useful in performing amore efficient Hibiscus hybridization and breeding in future.
        4,000원
        133.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        River channel dredging and riparian development have been influenced morphology and quantity of natural river habitat. We compared distribution of riverside land and alluvial island in the Nakdong River with field survey and remote sensing analysis after the 4 Large River Project in South Korea. We digitized geomorphological elements, includes main channel, riverside land, and alluvial island by using georeferenced aerial photos taken in pre-dredging (2008) and post-dredging (2012) periods. Field survey was followed in 2012 for a ground truth of digitized boundaries and identification of newly constructed wetland types such as pond, channel, branch, and riverine type. We found that during the dredging period, riverside land and alluvial island were lost by 20.2% and 72.7%, respectively. Modification rate of riverside land was higher in the section of river kilometer 50~90, 140~180, and 210~270. Alluvial island had higher change rate in the section of river kilometer 50~70, 190~210, and 270~310. Average change rate for the riverside land and alluvial island was - 1.02±0.14 km² ·10 km¯¹ and - 0.05±0.05 km² ·10 km¯¹, respectively. Channel shaped wetlands (72.5%) constituted large portion of newly constructed wetlands.
        4,000원
        134.
        2015.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO micro/nanocrystals at large scale were synthesized through the thermal evaporation of Al-Zn mixtures under air atmosphere. The effect of synthetic temperature and time on the morphology of the micro/nanocrystals was examined. It was found that the temperature and time affected the morphology of the ZnO crystals. At temperatures below 900 oC, no crystals were synthesized. At a temperature of 1000 oC, ZnO crystals with a rod shape were synthesized. With an increase in temperature from 1000 oC to 1100 oC, the morphology of the crystals changed from rod shape to wire and granular shapes. As the time increased from 2 h to 3 h at 1000 oC, tetrapod-shaped ZnO crystals started to form. XRD patterns showed that the ZnO crystals had a hexagonal wurtzite structure. EDX analysis revealed that the ZnO crystals had high purity. It is believed that the ZnO nanowires were grown via a vapor-solid mechanism because no catalyst particles were observed at the tips of the micro/nanocrystals in the SEM images.
        3,000원
        135.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 능소화를 대상으로 화분형태 및 RAW264.7 대식세포에서의 세포생존에 미치는 영향을 조사하여 유해성 여부를 파악하고자 한다. 주사전자현미경을 이용한 화분 형태를 확인해 본 결과, 화분립 형태는 장구형이고 발아구의 형태는 3공구형이며 화분 표벽 (extine)은 망상의 형태이고 외부로 돌출된 돌기는 관찰되지 않았다. 능소화 70% MeOH 부위별 (꽃, 잎, 줄기) 추출물 및 화밀을 24, 48시간 동안 농도별 (10, 20, 50, 100 μg mL-1)로 RAW264.7 대식세포에 처리한 후 MTT assay로 측정하였다. 그 결과, 능소화 추출물 및 화밀을 농도별로 24시간 처리하였을 때 모든 농도에서 99.0% 이상의 세포생존율을 보여 세포독성은 나타나지 않았다. 48시간 처리하였을 때 꽃, 잎, 줄기 추출물은 50 μg mL-1농도 이하에서 세포독성은 나타나지 않았으나, 화밀의 경우 저농도인 10 μg mL-1부터 농도의존적으로 세포독성이 높아지는 것을 확인하였다.
        4,000원
        136.
        2015.05 구독 인증기관·개인회원 무료
        In the present work, a new synthesis method has been reported for preparing high-quality NaA zeolite membrane. The present method involves pressure-driven hydrothermal gel coating method(HGCM) on seeded α-alumina support surface having pores of 0.1 and 0.7μm diameter before the secondary growth process. The experimental data revealed that the high-pressure injection of hydrothermal gel solution on α-alumina support surface helped in the pore filling and thin layer coating of gel particles, which promoted the formation of uniform, defect free, and dense zeolite layer. Pervaporative dehydration experiments were conducted for 50 wt.% ethanol-water mixture at 343K. The NaA zeolite membrane, which was prepared by HGCM process on the 0.7μm support, showed that the high total flux was 4.7 kg m-2h-1 and separation factor was more than >1000.
        137.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        저온스트레스에 따른 차나무 잎의 변화와 카테킨, 카페인, 아미노산대사 그리고 환원당 등 다양한 대사물의 함량 변화를 구명하였다. 저온스트레스 피해를 입은 실외포장의 차나무 잎은 세포크기, 기공 및 엽맥세포의 크기가 저온스트레스를 입지 않은 온실 재배 녹차잎에 비해 작았다. 저온스트레스 피해를 입은 실외포장의 차나무 잎에서 카페인과 카테킨의 함량은 온실 재배 차나무보다 높았다. 그러나 아미노산의 함량은 저온스트레스 피해를 입은 실외포장의 차나무 잎보다 온실에서 재배한 차나무가 높았다. 환원당 함량은 실외포장의 차나무에서 낮았다. 인위적 저온스트레스 처리 결과 환원당의 함량은 저온스트레스 처리 2시간까지는 증가하였다가 이후는 감소하였다. 이 결과는 저온스트레스가 차나무 잎의 형태적 변화와 더불어 카페인과 카테킨 그리고 당 등 대사물의 영향을 미친다는 것을 나타낸다.
        4,000원
        138.
        2015.03 구독 인증기관 무료, 개인회원 유료
        Minimal inhibitory concentration (MIC) is the lowest concentration of antibiotics that inhibits the visible growth of bacteria. It has been reported that sub-MIC of antibiotics may result in morphological alterations, along with the biochemical and physiological changes in bacteria. The purpose of this study was to examine morphological changes of Aggregatibacter actinomycetemcomitans, after the treatment with sub-MIC metronidazole and penicillin. The bacterial morphology was observed with scanning electron microscope, after incubating with sub-MIC antibiotics. The length of A. actinomycetemcomitans was increased after the incubation with sub-MIC metronidazole and penicillin. Sub-MIC metronidazole and penicillin inhibited bacterial division and induced long filaments. Our study showed that metronidazole and penicillin can induce the morphological changes in A. actinomycetemcomitans.
        4,000원
        139.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined how L2 learners of English process morphologically complex words (e.g., bareness) and psuedowords (e.g.,*boilness) to investigate if the L2 processing of derivational morphology is subject to critical period effects. It has been claimed that native speakers rely on procedural memory to process morphologically complex words, while L2 learners tend to utilize declarative memory to process them (Ullman, 2001, 2004, 2005). According to Ullman, L2 learners’ reliance on declarative memory for processing morphologically complex words is due to maturational changes in procedural memory. Two related experiments with a masked priming lexical decision task were conducted with two groups of Korean learners: early and late L2 learners. With regard to the results, early L2 learners showed stem priming effects for morphologically related prime-target pairs, which is indicative of morphological decomposition. On the other hand, late L2 learners did not provide any evidence of stem priming, indicating that they might have processed the morphologically complex word/pseudoword as a whole unit. These data suggest that the L2 processing of late learners is different from that of early learners.
        5,700원
        140.
        2014.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Diameter-controlled tin oxide nanofibers have been successfully prepared using electrospinning and a subsequent calcination process; their diameters, morphologies, and crystal structures have been characterized. The diameters of the as-spun nanofibers can be decreased by lowering the concentration of a polymer and a tin precursor in the electrospinning solution because of the decrease in the solution viscosity. The crystal structure of the nanofibers calcined at various temperatures from 200˚C to 800˚C has been proved to be the tetragonal rutile of tin oxide; crystallinity is improved by increasing the temperature. However, nanofibers with lower concentrations of tin precursor do not maintain their fibrous structures after calcination at high temperatures. In this study, the effect of the relationship between the precursor concentration and the calcination temperature on the diameter and the morphology of the tin oxide nanofiber has been systematically investigated and discussed.
        4,000원