• The Korean Journal of Malacology
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• v.27 no.3
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• pp.159-165
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• 2011

The anatomy and ultrastructure of the digestive diverticulum of Saxidomus purpuratus were described using light and electron microscopy. The digestive diverticulum of dark green color was situated on the gonad and connected to stomach by a primary duct. Digestive diverticulum is composed of numerous digestive tubules. The epithelial layer of digestive tubule, which is simple, is composed of basophilic cells and digestive cells. Basophilic cells are columnar in shape, and the electron density is higher than that of the digestive cell. The cytoplasm has a well-developed endoplasmic reticulum, tubular mitochondria, Golgi complex and membrane-bounded granules of high electron density. Digestive cells are columnar in shape, with development of microvilli on the free surface. Pinocytic vasicles, lysosomes and numerous mitochondria were observed in the apical cytoplasm of digestive cells. The results of this study suggest that basophilic cells and digestive cells in the digestive tubule are specialized in the extracellular and intracellular digestions, respectively.

• Applied Microscopy
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• v.41 no.4
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• pp.257-263
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• 2011

The microanatomy and ultrastructure of the digestive diverticulum of Mytilus galloprovincialis were described using light and electron microscopy. The digestive diverticulum of tawny color was surrounded the stomach and connected to stomach by a primary duct. Digestive diverticulum is composed of numerous digestive tubules. The epithelial layer of a simple digestive tubule, which is simple, is composed of basophilic cells and digestive cells. Basophilic cells are columnar in shape, and has a well-developed endoplasmic reticula, tubular mitochondria, Golgi complex and membrane-bounded granules of high electron density in the cytoplasm. Whereas digestive cells are columnar in shape, with development of microvilli and cilia on the free surface. Pinocytic vasicles, active lysosomes and numerous mitochondria were observed in the apical cytoplasm of digestive cells. The results of this study suggest that basophilic cell and digestive cell of the digestive tubule are specialized in the extracellular and intracellular digestion, respectively.

• Korean Journal of Ichthyology
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• v.31 no.4
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• pp.208-213
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• 2019

Spermatozoa of Aphyocypris chinensis was studied by transmission electron microscopy. The investiation revaled that, spermatozoa display a round head, a small midpiece and a long tail region. In the spermatozoa, the nucleus contains highly condensed homogeneous chromation with small electron lucent areas. The base of the nucleus is slightly invaginated laterally by the nuclear fossa which contains the proximal centriole. The two centrioles orientated at an obtus angle (130°) to each other. The midpiece encircles the flagellum and is completely separated from it by the cytoplasmic channel. The midpiece contains more than 12 mitochondria. The mitochondria are arranged in 4~5 layer and are asymmetrically distributed in the postnuclear cytoplasm. The mitochondria surround the proximal part of the flagellum. The flagellum has classical 9+2 axoneme and no lateral fins. The spermatozoa of A. chinensis are similar to those of other cyprinids having a spherical head with a shallow nuclear fossa, a short midpiece including the asymmetrical arrangement of mitochondria and the lateral insertion of flagellum. However, there are some differences in the orientation of centrioles and the number of the mitochondria.

• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.115-127
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• 1998

The digestive tract of the rockfish, Sebastes schlegeli composed of pharynx, esophagus, stomach, intestine, anus and ten or eleven pyloric caeca. Pyloric caeca is blind sac of banana shape, and that is originated from pyloric portion of the stomach. The relative length of gut(RLG), that is length of digestive tract to standard length, is about 1.56(n=10). Esophageal muscularis consists of thin outer layer of longitudinal muscle and thick inner layer of circular muscle. Mucosal epithelium consists of columnar epithelium with short microvilli and contains numerous mucous secretory cell. The mucosal folds of the stomach are regular, and the muscularis consists of longitudinal, oblique and circular muscle layer. The chief cell of the gastric gland have a tubular mitochondria, endoplasmic reticula and numerous secretory granules in electron-dense. However, parietal cell contains small mitochondria, endoplasmic reticula and vacuoles in low electron density. Mucosal epithelium of the pyloric caeca and intestine composed of columnar epithelium, goblet cell, rodlet cell and dark cell. Columnar absorptive cell in the pyloric caeca and intestine contains well developed mitochondria, endoplasmic reticula, vesiculated granules in high electron density, pinocytotic vesicles and multivesicular body. Rodlet cell have a well developed cytoplasmic capsule and the endoplasmic reticula in the cytoplasm. Dark cell showing a high electron density in the cytoplasm and contains well developed mitochondria. Columnar epithelium of the intestine have a well developed intercellular junction and the microvilli which contains actin filament originated from the cytoplasm. Mucosal epithelium of the intestine have a longer microvilli and more abundant goblet cells than in the pyloric caeca.

• Applied Microscopy
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• v.24 no.3
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• pp.1-9
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• 1994

Pardosa astrigera possessed eight eyes arranged in three rows on the frontal carapace. A pair of small anterior lateral eyes (ALE) flanked each side by an anterior median eyes (AME) lay along the anterior margin that was situated on the anterior row of clypeus. The anterior lateral eye was composed of cornea, vitreous body, and retina. Cornea was made up mainly of exocuticle lining the cuticle. Lens in anterior lateral eye was biconvex type which bulged into the cavity of the eyecup. Outer and inner central region of lens were approximately spherical with radius of curvature $5.6{\mu}m$ and $12.5{\mu}m$, respectly. Vitreous body formed a layer between the cuticular lens and retina. They formed biconcave shape. Retina of the anterior lateral eyes was composed of three types of cells: visual cells, glia cells, and pigment cells. The visual cells were unipolar neuron, as were the receptor of the posterior lateral eye. But cell body was unique to the anterior lateral eyes. They were giant cell, relatively a few in number, and under the layer of vitreous bodies. Each visual cell healed rhabdomeres for a short stretch beneath the cell body. Rhabdomes were irregulary pattern in retina and electron dense pigment granules scattered between the rhabdomes. Glia cell situated at the cell body of visual cell and glia cell process reached to rhabdomere portion. Below the rhabdome, tapetum were about $30{\mu}m$ distance from lens, which composed of 4-5 layers. It was about $25{\mu}m$ length that intermediate segment of distal portion of visual cell. Electron dense pigment granules between the intermediate segment were observed.

• Journal of the Korean Ceramic Society
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• v.42 no.1
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• pp.43-49
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• 2005

YSZ layer containing nano-sized particles has been deposited on the commercial A1203 substrate by Electron Beam Physical Vapor Deposition (EB-PVD). The role of coating rnjcrostructures of YSZ to indentation damage is studied. The different coating microsouctures are prepared by varying the substrate temperatures from $600^{circ}C$ to $800^{circ}C$ during the deposition. Microhardness test and Hertzian indentation are conducted on the $YSZ/Al_{2}O_{3}$ layered systems. The damage and flilure behaviors have been investigated according to the effect of microstructures and indentation loads. With increasing the substrate temperature during EB-PVD, the overall grain sizes are coarser and more faceted, which microsoucture ultimately influences on the indentation behavior, thus, YSZ/Al_{2}O_{3}$ layered system prepared at the substrate temperature of $800^{circ}C$ shows relatively higher damage tolerance.

• Journal of the KSME
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• v.55 no.7
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• pp.32-36
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• 2015

최근 화석 연료의 과다 사용에 따른 에너지 자원 고갈 및 환경오염에 대한 우려가 증가함에 따라 비화석연료 기반의 재생가능하고 지속가능하며, 환경친화성이 높은 에너지에 대한 관심이 급증하고 있다. 농산폐기물, 폐목재, 에너지작물, 도시고형폐기물, 미세조류, 거대조류 등 육상 및 해상에서 발생하는 바이오매스는 재생가능한 에너지원으로서 화석원료와는 달리 사용 후 발생하는 이산화탄소를 다시 흡수하는 탄소중립(carbon-nutral)의 특성을 갖고 있어 전세계적으로 많은 주목을 받고 있다. 바이오연료 중 당질계원료를 이용하는 바이오에탄올 및 식물성유지를 이용하는 바이오디젤은 현재 상업적인 생산이 이루어지고 있으나, 이들 1세대 바이오연료는 식량자원과의 경쟁이라는 원천적인 한계를 가지고 있고, 분자구조식에 산소를 포함하고 있기 때문에 기존 화석원료에서 출발하는 가솔린, 항공유 및 디젤과 비교하였을 때 에너지 함량이 낮은 단점이 있다. 따라서 기존 1세대 바이오연료에서 탈피하여, 식량자원과 경쟁이 없으며, 또한 분자구조식에 산소를 적게 포함하거나 아예 포함하지 않는 바이오연료("drop-in" 바이오연료) 생산에 많은 관심이 집중되고 있다. 이 글에서는 최근 그린공정으로 대표되는 초임계 유체를 이용한 "drop-in" 바이오연료를 제조하기 위한 바이오매스 액화의 기술동향을 소개하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.869-874
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• 2000

아홉 개의 계층구조 형태의 뉴런을 LINUX를 기초로 한 GENESIS를 이용하여 입력전류에 대한 각 뉴런의 신경전달 메카니즘을 분석하였고 마지막 뉴런에 미치는 활성전위 영향을 시뮬레이션을 해 보았다. 본 연 구에서는 다른 뉴런과 연결해주며 신호를 전달해주는 시냅스의 웨이트를 중간계층 뉴런에서 적게 연결하여 비정상 상태의 뉴런을 만들어 보았다. 시뮬레이션 결과 신경세포를 전기회로 적인 모델을 기준으로 설계한 뉴런은 미세한 자극의 변화해 매우 민감하게 반응 하였고, 마지막 뉴런 에서는 활성전위 간격이 정상상태의 다른 세포와 비교해 보았으며, 결과적으로 뉴런의 시냅스 웨이트가 적으면 신경전달에 이상 이 발생하여 세 포가 손상됨을 알 수 있었다.

• Anatomy & Biological Anthropology
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• v.31 no.4
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• pp.133-142
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• 2018

3D histology is a imaging system for the 3D structural information of cells or tissues. The synchrotron radiation propagation phase contrast micro-CT has been used in 3D imaging methods. However, the simple phase contrast micro-CT did not give sufficient micro-structural information when the specimen contains soft elements, as is the case with many biomedical tissue samples. The purpose of this study is to develop a new technique to enhance the phase contrast effect for soft tissue imaging. Experiments were performed at the imaging beam lines of Pohang Accelerator Laboratory (PAL). The biomedical tissue samples under frozen state was mounted on a computer-controlled precision stage and rotated in $0.18^{\circ}$ increments through $180^{\circ}$. An X-ray shadow of a specimen was converted into a visual image on the surface of a CdWO4 scintillator that was magnified using a microscopic objective lens(X5 or X20) before being captured with a digital CCD camera. 3-dimensional volume images of the specimen were obtained by applying a filtered back-projection algorithm to the projection images using a software package OCTOPUS. Surface reconstruction and volume segmentation and rendering were performed were performed using Amira software. In this study, We found that synchrotron phase contrast imaging of frozen tissue samples has higher contrast power for soft tissue than that of non-frozen samples. In conclusion, synchrotron radiation propagation phase contrast cryo-microCT imaging offers a promising tool for non-destructive high resolution 3D histology.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.194-202
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• 1996

Transmission electron microscopy has been used to characterize the dislocation structure in hot-pressed titanium diboride. The thin foil samples were prepared by the conventional ion beam thinning technique and reveal the main features associated with the dislocations ; low-angle grain boundaries with dislocation arrays, high-angle grain boundaries with ledges/steps on the boundary planes. The ledges/steps on the grain boundaries were characterized as the origin of defect structures such as dislocation formation or crack propagation near grain boundaries. A fraction of the high angle grain boundaries contained periodic arrays of grain boundary dislocations. The Burger's vectors of the dislocations in the $TiB_{2}$specimens were determined.