• Journal of Electrochemical Science and Technology
• /
• 제1권1호
• /
• pp.19-24
• /
• 2010

Alloying degree is an important structural factor of PtRu catalysts for direct methanol fuel cells (DMFC). In this work, carbon supported PtRu catalysts were synthesized by reduction method using anhydrous ethanol as a solvent and $NaBH_4$ as a reducing agent. Using anhydrous ethanol as a solvent resulted in high alloying degree and good dispersion. The morphological structure and crystallanity of synthesized catalysts were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM). CO stripping and methanol oxidation reaction were measured. Due to high alloying degree catalyst prepared in anhydrous ethanol, exhibited low onset potential for methanol oxidation and negative peak shift of CO oxidation than commercial sample. Consequently, samples, applying ethanol as a solvent, exhibited not only enhanced CO oxidation, but also increased methanol oxidation reaction (MOR) activity compared with commercial PtRu/C (40 wt%, E-tek) and 40 wt% PtRu/C prepared in water solution.

• Journal of Electrochemical Science and Technology
• /
• 제2권4호
• /
• pp.204-210
• /
• 2011

Thin film electrodes have been intensively studied for active materials and current collectors to enhance the electrochemical performance. Here, porous structures of nickel-based oxide films, consisting of nickel oxide and copper (II) oxide, which was derived from the copper substrate during the annealing process, were deposited on metallic copper foils. The half-cell tests revealed excellent capacity retention after $80^{th}$ charge/discharge cycles. Some films showed an excess of the theoretical capacity of nickel oxides, which mainly originate from partially oxidized copper substrates during annealing. These results exhibit that both a preparation method of an active materials and partially oxidized current collectors could be important roles to apply thin film electrodes.

• 환경생물
• /
• 제40권4호
• /
• pp.405-412
• /
• 2022

Suncheon Bay Ecological Park, possessing abundant fisheries and biological diversity, was registered as a Ramsar wetland in Korea. Approximately 300 bacterial strains were isolated from the Suncheon Bay in a comprehensive study of indigenous prokaryotic species conducted during 2019-2020 in South Korea. A total of 12 bacterial strains were identified using 16S rRNA gene sequencing, demonstrating >98.7% sequence similarity with validly published species. These species were determined to be unrecorded bacterial species in Korea. A total of six strains were isolated from brackish water and Phragmites communis Trin (reed) species. These unrecorded species were phylogenetically diverse and belonged to three classes, six orders, and ten genera. Regarding the genus and class levels, the previously unrecorded species belonged to Jiella, Martelella, Rhizobium, Paracoccus, Rhodovulum, and Altererythrobacter of the class Alphaproteobacteria; Mycolicibacterium, Demequina, and Microbacterium of the class Actinobacteria; Confluentibacter of the class Flavobacteria. The twelve species were further characterized by gram staining, colony and cell morphology, biochemical properties, and phylogenetic position.

• Journal of Species Research
• /
• 제6권spc호
• /
• pp.110-113
• /
• 2017

We collected three soil ciliates, Colpoda maupasi Enriquez, 1908, Tillina minima Alekperov, 1985, and Gonostomum singhii Kamra et al., 2008, in Korea. The two genera, Colpoda and Tillina, belong to the class Colpodea, and the other, Gonostomum belongs to the class Spirotrichea. We describe these species based on observations of live and protargol-impregnated specimens.

• ALGAE
• /
• 제23권1호
• /
• pp.63-69
• /
• 2008

The purpose of research was to find aerial algae and to investigate the change of color in each class of photosynthetic pigments in five stone cultural properties of Korea. It turned out to be a total of 29 taxa, including as 26 species, 1 variety and 2 unidentified species. Among them, Haplaosiphon fontinalis and Stigonema turfaceum were found to be newly recorded species of Korea. The average Chl-a concentration from the change of color in the stone cultural properties increased as its class; however, the class 5 showed lower values than the class 4, which was shown in previous studies. From the studies of algal distribution, chlorophytes appeared earlier than cyanophytes in stone cultural properties of algal infestation. Also, 50% or more of the five stone cultural properties already appeared to have bio-pollution.

• 대한의생명과학회지
• /
• 제12권3호
• /
• pp.201-208
• /
• 2006

PI3-kinase activity through p85, the regulatory subunit of class IA PI3-kinase, is indispensable for the growth, differentiation, and survival of skeletal muscle cells, but little is known about the function of other regulatory subunits such as p55 and p50. We examined the subcellular localization and the expression of the regulatory subunits of class IA PI3-kinase in L6 myoblasts. Both p55 and p50 as well as p85 were expressed in L6 myoblasts. Whereas p85 was localized at both cytosolic and nuclear tractions, p55 and p50 were localized at only the nuclear traction. During the differentiation of L6 myoblasts, the protein concentrations of both p55 and p50 were decreased but that of p85 was not significantly changed. Menadione-induced oxidative stress induced the translocation of p85 from cytosol to nucleus and the increase of p55 expression. These results suggest that the regulatory subunits of class IA PI3-kinase play an important role in L6 myoblasts.

• 보존과학회지
• /
• 제26권3호
• /
• pp.259-268
• /
• 2010

본 연구는 2007년 4월에서 6월까지 국내 8기의 석조문화재를 대상으로 환경요인과 엽록소 a 및 색에 따른 생물오염 등급을 평가하였다. 엽록소 a 의 경우 $16.2{\sim}136.6{\mu}g{\cdot}g^{-1}$의 농도를 나타냈으며, 색은 녹색에서 검정색의 범위로 나타났다. 생물오염등급 평가 결과 물걸리삼층석탑과 수타사삼층석탑은 3등급을 나타냈고, 괘석리사사자석탑 및 5개의 문화재는 4등급 이상을 나타냄으로써 생물오염이 심각한 것으로 나타났다. 기중조류는 총 32분류군이 출현하였으며, 이 중 남조강은 16분류군이고, 녹조강은 13분류군이며 규조강은 3분류군으로 나타났다. 엽록소 a와 생물오염등급 간의 상관 분석 결과, 상관계수는 0.43을 나타냈다. 엽록소 a와 출현종 간의 상관분석에서 Trebouxia sp.와 Chroococcus bituminosus는 상관계수 0.89와 0.65로써 높은 상관성을 나타냈다. 생물오염등급과 출현종의 경우에는 Chroococcus bituminosus, Aphanocapsa grevillei, Xenococcus acervatus, Chlorella vulgaris 및 Synechocystis pevalekii 등이 상관계수 0.54~0.65의 범위로 높은 상관성을 나타냈다.

• 환경영향평가
• /
• 제28권2호
• /
• pp.169-182
• /
• 2019

낙동강 상류 수계에 위치한 영강, 내성천과 위천을 대상으로 2016년 5월부터 10월까지 부착돌말류를 이용한 생물학적 수질 평가를 하였다. 부착돌말류는 이동성이 없어 장기적인 수질상태를 반영할 수 있다. 채집된 부착돌말류는 총 158 분류군으로 2목 3아목 8과 34속 143종 15변종으로 구성되어 있다. 영강은 Achnanthes convergens 와 Achnanthes minutissima, 내성천은 Nitzschia inconspicua, 위천은 Achnanthes minutissima, Cocconeis placentula var. lineata와 Navicula minima가 우점하였다. CCA 분석 결과, 낙동강 상류 수계에서는 전기전도도, 총인과 총질소가 부착돌말류의 종조성에 중요한 요인들로 나타났다. 상관분석 결과, 부착돌말지수들(DAIpo 와 TDI)은 서로 높은 상관성(0.87)을 보였다. 부착돌말지수(DAIpo와 TDI)를 이용한 생물학적 수질평가 결과, 영강은 대부분의 지점에서 A등급으로 평가되었다. 내성천은 A등급으로 평가된 N1을 제외한 모든 지점에서 C~D등급으로 평가되었다. 위천은 W1의 DAIpo가 B~C등급이나 TDI는 D등급으로 평가되어, 이 지점의 생물학적 수질 평가는 DAIpo보다 TDI의 결과가 더 불량한 것으로 나타났다. W2의 DAIpo와 TDI는 A~D등급으로 수질의 변화가 심하였다. W3와 W4의 DAIpo와 TDI는 대부분 B와 C등급으로 각각 평가되었다.

• Journal of Species Research
• /
• 제9권2호
• /
• pp.77-84
• /
• 2020

As a part of the research project "Survey of freshwater organisms and specimen collection," freshwater samples were collected from the Nakdong River. Among the bacterial isolates, we selected strains that showed higher than 98.7% 16S rRNA gene sequence similarity with confirmed bacterial species previously unreported in South Korea. The 14 new records to South Korea were phylogenetically diverse and belonged to four phyla, six classes, 11 orders, and 14 genera. At the genus level, these species were found to be affiliated with Reyranella, Ferrovibrio, Brevundimonas, and Aquidulcibacter of the class Alphaproteobacteria; Pseudomonas, Cellvibrio, and Photobacterium of the class Gammaproteobacteria; Paenibacillus and Bacillus of the phylum Firmicutes; Chryseobacterium, Flavobacterium, Pedobacter of the phylum Bacteroidetes; and Actinomadura and Leifsonia of the phylum Actinobacteria. These species were further characterized by examining their Gram reaction, colony and cell morphologies, biochemical properties, and phylogenetic positions. The detailed descriptions of these 14 previously unreported species are provided.

• Journal of Species Research
• /
• 제8권2호
• /
• pp.191-196
• /
• 2019

In 2015 and 2017, the National Institute of Biological Resources has isolated four unrecorded prokaryotic species designated as R-1-5, R-2-13, R-2-1, and R-1-8 from the peatland soil of Yongneup. Phylogenetic analysis based on 16S rRNA gene sequence similarity determined the four strains (R-1-5, R-2-13, R-2-1, R-1-8) were most closely related to Curvibacter lanceolatus (99.93%), Massilia brevitalea (98.7%), Pseudomonas lini (99.54%), and Pseudomonas vancouverensis (99.93%), respectively. The four unrecorded strains belong to the phylum Proteobacteria, in which the genera Curvibacter and Massilia are assigned to the class Betaproteobacteria, and the genus Pseudomonas to the class Gammaproteobacteria. Since there are no publications or official reports on these four strains, these four species are new records to Korea. The strains were further characterized by Gram reaction, colony and cell morphology, basic biochemical properties, and phylogenetic position. Descriptive information of the four unrecorded species is provided.