• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.333-336
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• 2008

We have studied on optical properties of advanced S-IPS with a fine pitch electrode and a new finger design. Transmittance of panel increases with decreasing of width and angle of finger electrode. In order to improve transmittance, fine pitch electrode of ${\sim}2{\mu}m$ and rubbing angle of 10 degree have been adopted. Various optical performances are defined as the function of finger design and field intensify across the IPS pixel electrodes. We have developed the advanced electrode structures with a high performance. As a result, the optical properties of 42" full HD with 120Hz frequency shows high transmittance over 5%, contrast ratio of 1800:1, gray-to-gray response time of 4.4ms, respectively. And also we have studied that the moving picture quality of IPS LCD is related with design parameters of IPS cells and finger shape.

• Animal cells and systems
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• 제13권2호
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• pp.161-167
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• 2009

The cuticle of spider's exoskeleton is a hydrophobic and non-adhesive material, but the jumping spiders have the distinctive attachment apparatus for adhesion on smooth dry surface without sticky fluids. We have examined the whole tarsal appendages of the jumping spider, Plexippus setipes with using scanning electron microscope to reveal the fine structural characteristics of the dry adhesion system. All eight legs have the scopulae with a pair of claws on the tip of feet. Each scopula is composed of two groups of setae that are capable of dry adhesion on smooth surface, and the hook structure of the claw is advanced to move on the rough surface. The setae toward the bottom of the tarsal segment are densely covered by numerous setules on the underside which broadened from middle to distal portion. It has been revealed by this research that the contact area of the setule is always a triangular shape, and these cuticular surfaces are connected by the elongated stalks from the underlying setae. It is likely that the nano-scale structures including a triangular depression and a longitudinal groove on each setule could functionate when the spider detach its feet from the substrate.

• International Journal of Concrete Structures and Materials
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• 제8권4호
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• pp.301-307
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• 2014

Rice husk ash (RHA) is classified as a highly reactive pozzolan. It has a very high silica content similar to that of silica fume (SF). Using less-expensive and locally available RHA as a mineral admixture in concrete brings ample benefits to the costs, the technical properties of concrete as well as to the environment. An experimental study of the effect of RHA blending on workability, strength and durability of high performance fine-grained concrete (HPFGC) is presented. The results show that the addition of RHA to HPFGC improved significantly compressive strength, splitting tensile strength and chloride penetration resistance. Interestingly, the ratio of compressive strength to splitting tensile strength of HPFGC was lower than that of ordinary concrete, especially for the concrete made with 20 % RHA. Compressive strength and splitting tensile strength of HPFGC containing RHA was similar and slightly higher, respectively, than for HPFGC containing SF. Chloride penetration resistance of HPFGC containing 10-15 % RHA was comparable with that of HPFGC containing 10 % SF.

• 대한세포병리학회지
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• 제13권1호
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• pp.28-32
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• 2002

Malignant myoepithelioma (myoepithelial carcinoma), is a very rare malignant epithelial accounting for less than 1% of all salivary gland tumors and has an intermediate malignant potential. We report a case of malignant myoepithelioma arising in the left parotid giand in a 54-year-old man, which was difficult to differentiate from pleomorphic adenoma and other malignant salivary gland neoplasms. Fine needle aspiration cytology of the parotid gland showed cellular smear, composed of overlapped sheets and clusters or individually scattered tumor cells without any acinic or ductal structures. The tumor cells were rather uniform, with distinct cell borders and moderate amount of cytoplasm. The eccentrically located nuclei were oval to round and pleomorphic and showed prominent nucleoli. A few clear cells were noted in the cellular aggregates Metachromatic matrix was seen between individual tumor cells in a lacelike fashion, resembling pleomorphic adenoma. According to the immunohistochemical staining, we recognized that the component cells are myoeplthelial in nature, showing reactivity for the S-100 protein, vimentin, and actin.

• 대한세포병리학회지
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• 제13권1호
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• pp.42-46
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• 2002

Epithelial-myoepithelial carcinoma(EMC) is a rare, low grade malignant tumor of the salivary glands. The EMC has a distinctive histological appearance comprising ductal structures with an inner epithelial cell component and an outer layer of myoepithelial cells which show plump clear cytoplasm. The cytologic features of the EMC have been rarely described. A correct cytological diagnosis to this rare tumor is difficult with high false negative rate. We report a case of EMC in which fine needle aspiration cytologic findings were misinterpreted as a pleomorphic adenoma.

• 폴리머
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• 제39권2호
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• pp.261-267
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• 2015

The inclusion complexes (ICs) between polylactic acid (PLA) and ${\beta}$-cyclodextrin (CD) were prepared by co-precipitation method in this work. The orthogonal experiments were designed to investigate the influence of different factors on the formation of inclusion complexes. The results suggested that the optimum scheme of inclusion compounds could be obtained when the feeding ratio of CD to PLA (wt%) was 20:1, stirring speed was 6 kr/min and the stirring time was 30 min. The structures and properties of the inclusion complexes were characterized by $^1H$ NMR, FTIR, DSC, FT-Raman, XRD and TGA. The DSC results demonstrated that the crystallization behavior of the inclusion complexes nearly disappeared. It was found that ${\beta}$-CD-PLA inclusion complex had a better thermal stability compared with the neat PLA. The model of the inclusion complexes was proposed on the basis of XRD, $^1H$ NMR and DSC results.

• Journal of Welding and Joining
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• 제20권3호
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• pp.67-73
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• 2002

In an attempt to evaluate the feasibility of friction stir welding(FSW) for joining carbon steels, microstructures and mechanical properties of friction stir welded carbon steels with different grain structures were investigated. In comparison of O-type stir zone(SZ) appeared in various aluminium alloys, configuration of SZ in friction stir welded carbon steels displayed U-type. Plastically deformed pearlite band structure was identified to surround the SZ, indicating the existence of so-called thermo-mechanically affected zone(TMAZ). However, the TMAZ of carbon steels was much narrower than that of Al alloys. The microstructures of both stir zone and TMAZ revealed bainite matrix in a conventional carbon steel for shipbuilding, while, in the same region, ferrite matrix microstructures were formed in a low carbon fine grained steel. The conventional carbon steel showed superior stirring workability to that of the fine grained carbon steel. The yield and tensile strength of the friction stir welded joints were comparable to those of the base metals, and the elongation in welded joints demonstrated excellent ductility. Absorbed energy in SZ of the fine grained carbon steel was ten times higher than that obtained from conventional submerged arc weld metal of the same steel. Based on these results, the application FSW to carbon steels was found to be feasible.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.259-262
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• 2009

Several universities in Korea are beginning studies related to soft stamping processes but since the studies are done with manual works thus systematic tests can't be performed due to difficulties in producing reproducible and repeatable fine patterns. Therefore, the phenomenon of destruction of the pattern forms of elastic polymers occurred during working because of inconsistent printing pressures and pinting time and there have been difficulties in maintaining flatness or producing uniform and fault-free fine structures in pinting large areas and also, there have been difficulties in multi-layered processes as patterns were changed by contacts in registering and errors in alignments. The purpose of development of this technology is to improve the process of soft lithography so that contacts between PDMS stamps and metal coated substrates in order to develop a stamp printing device that can not only shorten but also optimize processes, secure reproducibility and repeatability and is advantageous in printing large areas. Also, using this technology, this author is to develop equipment technologies and applied technologies for nano grade pattern printing processes with new concepts based on fine contact printing processes in order to apply them to diverse nano pattering processes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.834-837
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• 2005

Structural Dynamics Modification (SDM) is a very effective technique to improve structure's dynamic characteristics by adding or removing auxiliary structures, changing material properties and shape of structure. Among those of SDM technique, the method to change shape of structure has been mostly relied on engineer's experience and trial-and-error process which are very time consuming. In order to develop a systematic method to change structure shape, surface grooving technique is studied and successfully applied to HDD cover model. At first, to check the effect of mesh size, surface grooving technique was tested to the fine HDD cover FEmodel. And fur the more efficient method, the algorithm is modified. Removing the low-valued modal strain energy element among the target domain, computational effort can be greatly reduced and the result of simulation is similar with the other simulation result.

• Advances in concrete construction
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• 제15권6호
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• pp.405-417
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• 2023

While ultra-high performance concrete (UHPC) is commonly reinforced with micro straight steel fibers in existing applications, studies have indicated that the use of deformed steel macro-fibers leads to enhanced ductility and post-peak responses for UHPC structural elements, which is of particular importance for earthquake-resistant structures. However, there are potential concerns regarding the use of UHPC reinforced with macro-fibers due to the issues of workability and fiber distribution. The objective of this study was to address these issues by extensively investigating the restricted and non-restricted deformability, filling ability, horizontal and vertical velocities, and passing ability of UHPC containing macro hooked-end steel fibers. A new approach is suggested to examine the homogeneity of fiber distribution in UHPC. The influences of ultra-fine fillers and steel macro-fibers on the workability of fresh UHPC and the mechanics of hardened UHPC were examined. It was found that although increasing the ratio of quartz powder to cement led to an improvement in the workability and tensile strain hardening behavior of UHPC, it reduced the fiber distribution homogeneity. The addition of 1% volume fraction of macro-fibers in UHPC improved workability, but reduced its compressive strength, which is contrary to the effect of micro-fiber inclusion in UHPC.