• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.4
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• pp.455-467
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• 2001

In this study, the stacking phase shift effect on the effective property and stress distribution was investigated for 8-harness satin weave textile composites under uni-axial tension. Textile configurations with varied phase shifts were modeled by unit cells and repeating boundary conditions were applied at the outer periodic surfaces. The effective property and stress were calculated by the unit cell analysis using macro-element to reduce the computational resource. It was found that stresses were dependent on the variation of tow arrangement of adjacent layers. The in-phase and the shifted configurations showed large differences in the stress distribution pattern. The stress level was very high in the resin region and the distribution of the maximum stresses was widely scattered.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.158-161
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• 2006

SiC materials have been extensively studied for high temperature components in advanced energy conversion system and advanced gas turbine. However, the brittle characteristics of SiC such as law fracture toughness and law strain-to fracture impose a severe limitation on the practical applications of SiC materials. SiC/SiC composites can be considered as a promising candidate in various structural materials, because of their good fracture toughness. In this composite system, the direction of SiC fiber will give an effect to the mechanical properties. It is therefore important to control a properdirection of SiC fiber for the fabrication of high performance SiC/SiC composites. In this study, unidirection and two dimension woven structures of SiC/SiC composites were prepared starting from Tyranno SA fiber. SiC matrix was obtained by nano-powder infiltration and transient eutectoid (NITE) process. Effect of microstructure and density on the sintering temperature in NITE-SiC/SiC composites are described and discussed with the fiber direction of unidirection and two dimension woven structures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.9
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• pp.2770-2781
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• 1996

Longitudinal shear modulus of continuous fiber reinforced 2-phase composites is predicted by theoretical and numerical analysis methods. In this paper, circular, hexagonal and rectangular shapes of reinforced fiber are considered using unit cell concept. And fiber array is regular rectangular and hexagonal fiber arrangement. Longitudinal shear modulus is a function of fiber distribution pattern and fiber volume change. It is found that the rectangular array has a higher longitudinal shear modulus than the hexagonal one. Also, the rectangular fiber shape in lower fiber volume fraction and the circular fiber shape in higher fiber volume fraction show the higher longitudinal shear modulus. And it has been found that the theoretical and numerical predictions of the longitudinal shear modulus give a good agreement with the experimental data at lower fiber volume fraction. Both the distance and stress transfer between the fibers are discussed as the major determing factors.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.275-284
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• 2006

This research investigated the morphological changes of folliculus ovary according to the dose of the X-rays when mice were exposed to X-rays, in terms of histochemical reaction. Dyeing methods such as Masson's trichrome method and reticular fiber method were used. The morphological changes of growing folliculus ovary got distinct as the dose of X-rays increased. Especially, the nuclei of granular cells showed manifest condensation and the changes of the transparent zone were distinct. As a result of histochemical reaction according to Masson's trichrome method and reticular fiber method, the changed granular cells, the deformed basilar membrane of folliculus ovary and the abnormal arrangement of the reticular fiber were observed.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.573-580
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• 2009

This paper presents the mix composition, production method, and curing condition applied to the extruded ECC(Engineered Cementitious Composite) panel which are able to exhibit multiple cracking and potential pseudo strain-hardening behavior. In addition to the production technique of extruded ECC panel, the effect of fiber distribution characteristics, which are uniquely created by applying extrusion process, on the flexural behavior of the panel is also focussed. In order to demonstrate fiber distribution, a series of experiments and analyses, including image processing/analysis and micro-mechanical analysis, was performed. The optimum mix composition of extruded ECC panel was determined in terms of water matrix ratio, the amount of cement, ECC powder, and silica powder. It was found that flexural behavior of extruded ECC panel was highly affected by the slight difference in mix composition of ECC panel. This is mainly because the difference in mix composition results in the change of micro-mechanical properties as well as fiber distribution characteristics, represented by fiber dispersion and orientation. In terms of the average fiber orientation, the fiber distribution was found to be similar to the assumption of two dimensional random distribution, irrespective of mix composition. In contrast, the probability density function for fiber orientation was measured to be quite different depending on the mix composition.

• The Korean Journal of Cytopathology
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• v.9 no.1
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• pp.105-110
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• 1998

Adenomyoepithelioma is an uncommon benign tumor of the breast. We present the fine needle aspiration cytologic features of adenomyoepithelioma in a 23 year-old Korean women, initially diagnosed as fibroadenoma. Aspiration cytologic findings of the left breast mass revealed high cellularity, small to medium sized, less cohesive epithelial clusters, rich naked cells and amorphous materials on background. The epithelial cells were round and uniform with no cytologic atypia or mitosis. Myoeplthelial cells were conspicuous with peripheral rimming along the epithelial clusters. Small amount of fibrotic stromal tissues were observed. Distinguishing features from typical fibroadenoma are less tight epithelial clusters, dyscohesive epithelial cell aggregates, more abundant naked cells and scant stromal tissue fragments.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.68-73
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• 2017

The removal of particulate matter ranging from $0.01{\mu}m{\sim}10{\mu}m$ can be performed by using membrane filters composed of fibers. Electrospinning techniques offer the production of very thin fibers with a uniform fiber diameter over conventional techniques including template synthesis, melt-blown, phase separation, etc. Air filtration will be improved with electrospun membranes due to the open pore structures, high porosity, and large surface area of the membranes. In the present study, filtration efficiency increased with pore size decrease and fiber density increase induced by carbon nanotube and the increased CA (cellulose acetate) concentration during electrospinning process.

• Journal of Yeungnam Medical Science
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• v.7 no.2
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• pp.27-37
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• 1990

To investigate the changing patterns of microfilament and microtubule arrangement and influence of myocardial cells and colchicine to microfilament and microtubule formation in cardiac endothelial cells the authors carried out indirect immunofluorescence stain for actin and tubulin with supernatant monoclonal antibodies. Secondary antibodies were IgG FITC conjugate. The results were summerized as follows. Fiberform reactions were stronger in the cells with many processes and spread cytoplasm and they became weaker after the endothelial cells formed monolayer. In the endothelial cells cocultured with myocardial cells the fiberform of the microtubule became less visible compared to control group but fiberform of the microtubule maintained strong intensity as endothelial cells formed monolayer. In the group treated with colchicine, there were no visible differences in microfilaments compared to control group but fiberform of microtubule revealed weaker intensity after colchicine treatment. The intensity of microtubule fiberform returned to control level after 2 days.

• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.771-778
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• 2014

This paper concerns the flexural behavior of hybrid steel fiber-reinforced ultra high performance concrete (UHPC) beams. It presents experimental research results of hybrid steel fiber-reinforced UHPC with steel fiber content of 1.5% by volume and steel reinforcement ratio of less than 0.02. This study aims at providing realistic information about UHPC beams in bending in order to establish a reasonable prediction model for flexural resistance in structural code in the future. The experimental results show that hybrid steel fiber-reinforced UHPC is in favor of cracking resistance and ductility of beams. The ductility indices range through 9.2 to 15.2, which means high ductility of UHPC. Also, the flexural capacity of beam which contains stirrups in pure bending zone is similar to that of beam which does not contain stirrups in pure bending zone. This result represents that the flexural capacity is not affected by the presence of stirrups whose spacing is 150 mm in bending zone.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1385-1391
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• 1996

Solitary fibrous tumor of the pleura has been classified as a type of mesothelioma. This tumor have been recently described and distinguished from the mesothelioma, immunohistochemically and elect r om ic ro scop ical 1 y Thls 65 years female was admitted with right chest pain, coughing and dysnea. Chest X-ray and C-T scan showed a huge mass in the right thorax. Right thoracotomy was done and a 12$\times$12$\times$6cm(400gm) sized mass was excised, and the tumor had metastasized to the diaphragm, parietal pleura and lung parenchyma. Microscopically, the tumor Is composed of oval-round and plump spindle cells with diffuse pattern. There are occasional mitoses (311 OHPFS) and invasion to lung parenchyma. The immunohistochemical and electromicroscopical findings are consistent with malignant solitary fibrous tumor of the pleura. We experienced a case of pleural malignant solitary fibrous tumor and report this case with the review of literature.