• Animal Systematics, Evolution and Diversity
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• 제20권2호
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• pp.171-178
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• 2004

해안의 소나무 아래 토양과 하수처리장 폭기조에서 채집된 섬모충이 각각 Oxytricha balladyna와 O. longa으로 동정되었다. 이 종들은 한국에서 처음 보고 되는 것으로 생체표본과 protargol로 염색한 표본에 근거하여 재기재하였다. 유사 종들과 비교한 결과 Oxytricha balladyna는 한 개의 소핵이 두 개의 대핵사이에 위치하고. 5개의 후방극모, 3개의 미극모, 5열의 등쪽섬모열이 있으며 세포질에 granule이 없다. O. longa는 소핵이 각각 대핵 부근에 한 개씩 위치하며, 3개의 postoral ventral cirri가 직선상으로 배열하며 후방극모 (transverse cirri)와 멀다. 4개의 후방극모, 2개의 미극모와 4열의 등쪽섬모열이 있으며 특히 세포질에 Yellow-green granules이 관찰되어 특이하였다.

• Animal Systematics, Evolution and Diversity
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• 제12권3호
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• pp.203-210
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• 1996

중국과 한국에 서식하는 흰넓적다리붉은쥐(Apodemus Peninsulae) 3아종의 표본들의 4개 외부형질과 27개 두골형질들을 다변량통계 방법으로 분석하였다. 4개형(form)으로 나뉘 어졌는데, 한국의 월악산과 연천의 아종 peninsulae와 중국의 길림과 흑룡성의 아종 praetor 는 가장 큰 형이며, 중국 내몽고의 아종 praetor와 중국 산서와 산동성의 아종 sowerbyi는 큰형이고, 중국 북경의 아종 sowerbyi는 중간 형이며, 중국 신강성의 아종 sowerbyi는 작은 형이었다. Corbet(1978)는 아시아 대륙내의 흰넓적다리붉은쥐의 분포범위에서는 2아종 (peninsulae and sowerbyi)으로 분류된다고 하였지만, 형태적 형질을 이용한 본 연구에서 아 종 praetor와 peninsulae가 큰 형이었고, 아종 sowerbyi는 3개의 형태로 나뉠 정도로 다양했 으므로, 단지 2아종으로만 분류할 수가 없음이 밝혀졌다. 중국과 러시아의 다른 표본들을 포 함한 계속되는 연구가 본 종의 확실한 분류의 완성을 위해서 필요하다.

• Animal Systematics, Evolution and Diversity
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• 제19권2호
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• pp.227-235
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• 2003

2002년 제주도의 한 웅덩이에서 채집된 섬모충류를 실험실에서 분리, 배양한 결과 하모류의 이끼토양자라하모충(Euplotes muscorum Dragesco, 1970)으로 동정되었으며 한국에서 처음으로 보고되어 재기재한다. 기재는 생체 표본 관찰, protargol impregnation 그리고 형태통계에 기초하여 기술하였다. 이 종의 형태적 특징은 몸길이 63-78${\mu}m$, 폭 40-52${\mu}m$, 9개의 전방복극모, 5개의 후방극모, 4개의 미극모, 한 개의 대핵과 소핵, 몸길이의 약 2/3을 덮고 있는 막판구대는 32-35개의 구부막판으로 이루어졌고, 8개의 등쪽섬모열, 중앙의 등쪽섬모열의 섬모는 20-24개, 등쪽섬모배열은 complex type 등의 특징들을 가진다. 이 종은 이끼자라하모충(E. muscicola Kahl,1932)과 매우 비슷하지만 이끼토양자라하모충은 8개의 등쪽섬모열, complex type의 등쪽섬모배열을 가지는데 반해 이끼자라하모충는 9개의 등쪽섬모열, multiple type의 등쪽섬모배열을 가지는 형태적 특징을 각각 나타낸다.

• Journal of Welding and Joining
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• 제33권2호
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• pp.8-13
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• 2015

This study was carried out to evaluate mechanical properties of the jointed Al6061/HT590 alloys by friction stir welding (FSW). FSW was conducted under the conditions with tool rotating speed of 500 RPM and traveling speed of 300 mm/min., where Ar gas was introduced to prevent the materials from corrosion during the welding process. Electron back-scattering diffraction (EBSD) was used to characterize microstructures such as grain size, misorientation angle and crystal orientation. Evolution of intermetallic compounds in Al6061 during the process were examined in terms of morphology, size and aspect ratio at three distinct zones Al base material, heat affected zone and stir zone, where transmission electron microscope (TEM) was used. It was revealed that FSW gave rise to refinement of grains as well as growth of intermetallic compounds in Al6061. The morphological changes of intermetallic compounds exerted an influence on mechanical properties, resulting in occurrence of fracture in the part of the base material instead of the jointed parts (heat affected zone and stir zone). This study systematically evaluated the microstructural evolutions during the FSW for joining Al6061 with HT590 and their effect on mechanical properties.

• 한국분말재료학회지
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• 제10권1호
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• pp.26-33
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• 2003

Al-l4wt.%Ni-l4wt.% Mm(Mm=misch metal) alloy powders rapidly solidified by the gas atomization method were subjected to mechanical milling(MM). The morphology, microstructure and hardness of the powders were investigated as a function of milling time using scanning electron microscopy(SEM), transmission electron microscopy(TEM) and Vickers microhardness tester. Microstructural evolution in gas-atomized Al-l4wt.%Ni-l4wt.% Mm(Mm=misch metal) alloy powders was studied during mechanical milling. It was noted that the as-solidified particle size of $200\mutextrm{m}$ decreases during the first 48 hours and then increases up to 72 hours of milling due to cold bonding and subsequently there was continuous refinement to $20\mutextrm{m}$ on milling to 200 hours. Two microstructurally different zones, Zone A, which is fine microstructure area and Zone B, which has the structure of the as-solidified powder, were observed. The average thickness of the Zone A layer increased from about 10 to $15\mutextrm{m}$ in the powder milled for 24 hours. Increasing the milling time to 72 hours resulted in the formation of a thicker and more uniform Zone A layer, whose thickness increased to about $30~50\mutextrm{m}$. The TEM micrograph of ball milled powder for 200 hours shows formation of nano-particles, less than 20 nm in size, embedded in an Al matrix.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1494-1500
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• 2012

Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.

• Animal Systematics, Evolution and Diversity
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• 제28권3호
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• pp.192-207
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• 2012

To supply the morphological and ecological information of oligotrich ciliates in Korea, water samples were seasonally collected in Gwangyang Bay and Jinhae Bay from August, 2010 to February, 2012 and processed by quantitative protargol staining method. As a result, six species belonging to the genus Strombidium Clapar$\grave{e}$de and Lachmann, 1859 are identified: Strombidium emergens Kahl, 1932; S. dalum Lynn et al., 1988; S. epidemum Lynn et al., 1988; S. tressum Lynn et al., 1988; S. bilobum Lynn and Gilron, 1993; S. pollostomum Lynn and Gilron, 1993. These six species were newly reported from Korean coastal waters. Strombidium emergens is a middle sized Strombidium ($20-50{\mu}m$ in length) and has open and deep oral groove to girdle portion. Strombidium dalum is a small sized Strombidium (${\geq}20{\mu}m$ in length), that has torch-like spiral anterior membranelles and an inverted triangles-shaped macronucleus on the posterior pole. The small sized S. epidemum has conspicuous trichites surrounding the girdle portion and ventral membranelles distinctly separated from anterior membranelles. The small sized S. tressum has torch-like spiral and extremely long trichites among the cilia of anterior membranelles. The middle sized S. bilobum has a bilobed macronucleus. Strombidium pollostomum is also a small sized Strombidium but its ventral membranelles are continuously connected with anterior membranelles. The five species except S. emergens occurred frequently over the wide range of water temperatures and salinities.

• Animal Systematics, Evolution and Diversity
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• 제28권3호
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• pp.168-177
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• 2012

Two stichotrichid ciliates, collected from marine waters in Jeju Island, were identified as Afroamphisiella multinucleata Foissner et al., 2002 and Pseudokahliella marina (Foissner et al., 1982) Berger et al., 1985. They are recorded for the first time in Korea. The descriptions are based on examinations of living as well as protargol-impregnated specimens. These species are characterized as follows. Afroamphisiella multinucleata has a body size in vivo of $70-95{\times}20-35{\mu}m$; elongate rectangular in shape; contractile vacuole located slightly above mid-body. The adoral zone is bipartited into 3 distal and 13-17 proximal membranelles and occupies 28-35% of the body length. The frontal row comprises 1-4 cirri and one buccal cirrus. The amphisiellid median cirral row is composed of 14-21 cirri, 10-19 left marginal cirri, and 21-30 right marginal cirri. Cortical granules are yellowish. 11-20 globular/ellipsoidal macronuclear nodules arrange proximally along the cell margins. Pseudokahliella marina has a body size in vivo of $110-195{\times}40-110{\mu}m$ and broadly elliptical in shape. The adoral zone of the membranelles occupies 50-60% of the body length, and is composed of 41-70 membranelles. A prominent frontal scutum is present. The contractile vacuole is located below the mid-body. There are 11-13 frontoventral rows, including marginal rows. Caudal cirri and transverse cirri are absent. Three invariable non-fragmented bipolar dorsal kineties are present. The left and right marginal rows are composed of 22-35 and 28-40 cirri, respectively. Colourless cortical granules are present. 8-11 spherical/ellipsoidal macronuclear nodules are connected with each other by thread-like tructures, forming an inverted C-shape.

• 마이크로전자및패키징학회지
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• 제27권3호
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• pp.83-88
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• 2020

최근 스마트폰 산업의 발전으로 인하여 실사용 환경에서 유연소자의 기계적 거동에 대한 연구가 많이 이루어지고 있다. 유연소자 박막은 두께가 나노 단위이고, 기존의 시험법으로 측정하기 어려워 주로 나노압입시험을 이용하여 경도, 탄성계수 등의 특성을 구하고 있다. 그러나 현재 널리 쓰이고 있는 분석법(Oliver-Pharr Method)은 기판의 영향이 이론적으로 고려되지 않아 단순히 적용하기에는 무리가 있다. 따라서 본 연구에서는 기판 영향을 고려한 타 연구자들의 모델에 대한 적용성을 확인하고, 압입자와 시편 표면에서 발생하는 소성쌓임 현상(pile-up)에 대해 압입깊이의 보정을 실시하였다. 유연소자 박막의 탄성계수를 평가하고 검증하기 위하여 폴리이미드 및 실리콘 웨이퍼 기판 위에 금속, 비정질 박막을 증착하여 실제 실험을 수행하여 비교하였다.

• 천문학회보
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• 제39권2호
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• pp.50-50
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• 2014

We present a new catalog of galaxies in the wider region of the Virgo cluster, based on the Sloan Digital Sky Survey (SDSS) Data Release 7. The Extended Virgo Cluster Catalog (EVCC) covers an area of 725 deg2 or 60.1 Mpc2. It is 5.2 times larger than the footprint of the classical Virgo Cluster Catalog (VCC) and reaches out to 3.5 times the virial radius of the Virgo cluster. We selected 1324 spectroscopically targeted galaxies with radial velocities less than 3000 km s-1. In addition, 265 galaxies that have been missed in the SDSS spectroscopic survey but have available redshifts in the NASA Extragalactic Database are also included. Our selection process secured a total of 1589 galaxies of which 676 galaxies are not included in the VCC. The certain and possible cluster members are defined by means of redshift comparison with a cluster infall model. We employed two independent and complementary galaxy classification schemes: the traditional morphological classification based on the visual inspection of optical images and a characterization of galaxies from their spectroscopic features. SDSS u, g, r, i, and z passband photometry of all EVCC galaxies was performed using Source Extractor. We compare the EVCC galaxies with the VCC in terms of morphology, spatial distribution, and luminosity function. The EVCC defines a comprehensive galaxy sample covering a wider range in galaxy density that is significantly different from the inner region of the Virgo cluster. It will be the foundation for forthcoming galaxy evolution studies in the extended Virgo cluster region, complementing ongoing and planned Virgo cluster surveys at various wavelengths.