• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.937-939
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• 2007

Carbon nanotubes (CNTs) have used as an electron field emitter of the field emission display (FED) due to their characteristics of high-electron emission, rapid response and low power consumption. However, to commercialize the FED with CNT emitter, some fundamental problems regarding life time and emission efficiency have to be solved. In this study, we investigated the $TiO_2$ coated CNT as a field emitter. $TiO_2$ nanoparticles can coated on CNT surface by chemical solution method. $TiO_2$ nanoparticles had uniform size with the average size of about 2.4 nm to 3.1 nm. Field emission performance of CNT coated with $TiO_2$ nanoparticles was evaluated and discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.1
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• pp.26-32
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• 1996

This study was performed to determine the ideal mixing ratio of toothash and plaster of Paris. The histopathologic and histomorphometric study of bone response of five implant materials, toothash(Group A), tooth and plaster mixture, mixing ratio due to weight 2 : 1(Group B), 3 : 1(Group C), 4 : 1(Group D), and plaster Paris(Group E), were performed in rat calvarial defect. No sign of extensive inflammatory reaction was defected. Newly-formed bony ingrowth occurred in all experimental groups except for group E at 12 weeks after operation. Bone was deposited directly on the surface of implant materials. The highest rate of direct bony union between implant material and newly-formed bone occurred with the group B, followed group C, D, and A.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.869-872
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• 2005

This research studied robust design of column part for LCD transfer system. $1^{st}$ DOE(Design of Experiment)was conducted to find out main effect factors. 36 experiments were performed and their results were shows that the geometric parameters(Low-length, Side-length, Upper-thickness, Middle-thickness)are more important than other factors. The main effect plots shows that the maximum deflection of column is minimized with increasing Low-length, Side-length, under-thickness and Middle-thickness. $2^{nd}$ DOE was conducted to obtain RMS(Response Surface Method)equation 25 experiments were conducted. The CCD(Central Composite Design)technique with four factors were used. The coefficient of determination $(R^2)$ for the calculated RSM equation was 0.986. Optimum design was conducted using the RSM equation Multi-island genetic algorithm was used to optimum design. Optimum value for Low-length. Side-length, Upper-thickness and Middle-thickness were 299.8mm, 180.3mm, 21.7mm, 21.9mm respectively. An approximate value of 5.054mm in deflection was expected to be a maximum under the optimum conditions. Six sigma robust design was conducted to find out guideline for control range of design parameter. To acquire six sigma level reliability, the standard deviation of design parameter should be controlled within 2% of average design value.

• The Journal of Korean Obstetrics and Gynecology
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• v.31 no.2
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• pp.31-48
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• 2018

Objectives: This study was performed to observe the correlations between the results of ABR-2000 and DSOM / 3D-MAC to evaluate the feasibility of ABR-2000 as a oriental medical diagnostic criteria. Methods: We studied 547 women visiting ${\bigcirc}{\bigcirc}$ hospital from December 2012 to June 2015. The subjects were categorized in two groups, 'Hypotonia' and 'Non-Hypotonia' by the result of ABR-2000 and assessed the result of DSOM, 3D-MAC for each group. The differences of pulse wave factors by group also studied. Results: 1. There was no significant difference between two groups about the output frequency of pathogenic factors in DSOM while the result showed the higher correlation in Hypotonia group in terms of the companion tendency of pathogenic factors and syndromes formed by the combination of pathogenic factors. 2. The pulse waves of Hypotonia group were mostly slow, weak, tense and stiff than Non-Hypotonia group. Conclusions: 1. In Hypotonia group, yin deficiency (陰虛) factor was frequently accompanied and consumption (虛損) of various organs based on the yin deficiency (陰虛) was observed. It means chronic and severe condition of exhaustion syndrome (虛勞). 2. The result of 3D-MAC also means pathological feature of yin syndrome (陰 證) and consumption (虛損). Besides, lower scores of Body Surface Area (BSA), body weight, and Body Mass Index (BMI) were associated with body weakness (體瘦), a symptom of exhaustion syndrome (虛勞).

• Structural Engineering and Mechanics
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• v.88 no.1
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• pp.67-81
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• 2023

The reinforced concrete (RC) structures might need strengthening or upgradation due to adverse environmental conditions, design defects, modification requirements, and to prolong the expected lifespan. The RC beams have been efficiently strengthened using the near surface mounted (NSM) approach over the externally bonded reinforcing (EBR) system. In this study, the performance of RC beam elements strengthened with NSM-steel rebars was investigated using an experimental program and nonlinear finite element modeling (FEM). Nine medium-sized, rectangular cross-section RC beams total in number made up for the experimental evaluation. The beams strengthened with varying percentages of NSM reinforcement, and the number of grooves was assessed in four-point bending experiments up to failure. Based on the experimental evaluation, the load-displacement response, crack features, and failure modes of the strengthened beams were recorded and considered. According to the experimental findings, NSM steel greatly improved the flexural strength (up to about 84%) and stiffness of RC beams. The flexural response of the tested beams was simulated using a 3D non-linear finite element (FE) model. The findings of the experiments and the numerical analysis showed good agreement. The effect of the NSM groove and reinforcement on the structural response was then assessed parametrically.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.491-497
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• 2017

In recent years, 3D printing has received increasing attention due to its potential for direct fabrication beyond the traditional rapid prototyping. 3D printing has the advantage of being able to manufacture complicated shapes that were thought impossible to produce by traditional manufacturing processes. This advantage has driven applications of 3D printing to direct manufacturing of functional parts, such as lightweight structures and component integration. In this study, a porous shell structure is designed for the purpose of weight reduction and ventilation. Finite element (FE) analyses are performed to compare the effective stiffness of the porous structure with the conventional solid structure. Structural reinforcements are also considered in order to make up the stiffness reduction due to the porosity, and the relevant FE analyses are performed to investigate the effect of the reinforcement design on the bending stiffness. The optimized reinforced structure is then proposed through response surface analysis.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.507-513
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• 2000

ErbB3/HER3 is a cell surface receptor which belongs to the ErbB/HER subfamily of receptor protein tyrosine kinases. When expressed in NIH/3T3 cells, ErbB3 can form heterodimeric coreceptor with endogenous ErbB2. Among known intracellular effectors of the ErbB2/ErbB3 are mitogen-activated protein kinase (MAPK) and phosphoinositide (PI) 3-kinase. In the present study, we studied relative contributions of above two distinct signaling pathways to the heregulin-induced mitogenic response via activated ErbB3. For this, clonal NIH-3T3 cell lines expressing wild-type ErbB3 and ErbB3 mutants were stimulated with $heregulin{\beta}_1$. While cyclin D1 level was markedly high and further increased by treatment of heregulin in cells expressing wild-type ErbB3, the elimination of either Shc binding or PI 3-kinase binding lowered both levels. This result was supported by the reduction of cyclin $D_1$ expression by preteatment with MAPK kinase inhibitor or PI 3-kinase inhibitor before stimulation with heregulin. In accordance with the cyclin $D_1$ expression, elimination of either Shc binding or PI 3-kinase binding reduced the heregulin-induced DNA synthesis and cell growth rate. Our results obtained by the comparison of wild-type and ErbB3 mutants indicate that the full induction of the cell cycle progression through $G_1/S$ phase by ErbB3 activation is dependent on both Shc/MAPK and PI 3-kinase signal transduction pathways.

• Geomechanics and Engineering
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• v.19 no.3
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• pp.241-254
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• 2019

A finite element approach is presented to examine ground vibration characteristics under various moving loads in a homogeneous half-space. Four loading modes including single load, double load, four-load, and twenty-load were simulated in a finite element analysis to observe their influence on ground vibrations. Four load moving speeds of 60, 80, 100, and 120 m/s were adopted to investigate the influence of train speed to the ground vibrations. The results demonstrated that the loading mode in a finite element analysis is reliable for train-induced vibration simulations. Additionally, a three-dimensional finite element model (3D FEM) was developed to investigate the dynamic responses of a track-ballast-embankment-ground system subjected to moving loads induced by high-speed trains. Results showed that vibration attenuations and breaks exist in the simulated wave fronts transiting through different medium materials. These tendencies are a result of the difference in the Rayleigh wave speeds of the medium materials relative to the speed of the moving train. The vibration waves induced by train loading were greatly influenced by the weakening effect of sloping surfaces on the ballast and embankment. Moreover, these tendencies were significant when the vibration waves are at medium and high frequency levels. The vibration waves reflected by the sloping surface were trapped and dissipated within the track-ballast-embankment-ground system. Thus, the vibration amplitude outside the embankment was significantly reduced.

• Coupled systems mechanics
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• v.3 no.3
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• pp.305-318
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• 2014

The study deals with the physical modeling of a typical building frame resting on pile foundation and embedded in cohesive soil mass using complete three-dimensional finite element analysis. Two different pile groups comprising four piles ($2{\times}2$) and nine piles ($3{\times}3$) are considered. Further, three different pile diameters along with the various pile spacings are considered. The elements of the superstructure frame and those of the pile foundation are descretized using twenty-node isoparametric continuum elements. The interface between the pile and pile and soil is idealized using sixteen-node isoparametric surface elements. The current study is an improved version of finite element modeling for the soil elements compared to the one reported in the literature (Chore and Ingle 2008). The soil elements are discretized using eight-, nine- and twelve-node continuum elements. Both the elements of superstructure and substructure (i.e., foundation) including soil are assumed to remain in the elastic state at all the time. The interaction analysis is carried out using sub-structure approach in the parametric study. The total stress analysis is carried out considering the immediate behaviour of the soil. The effect of various parameters of the pile foundation such as spacing in a group and number piles in a group, along with pile diameter, is evaluated on the response of superstructure. The response includes the displacement at the top of the frame and bending moment in columns. The soil-structure interaction effect is found to increase displacement in the range of 58 -152% and increase the absolute maximum positive and negative moments in the column in the range of 14-15% and 26-28%, respectively. The effect of the soil- structure interaction is observed to be significant for the configuration of the pile groups and the soil considered in the present study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.637-649
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• 2020

An ideal 3D primitive equation model is implemented to investigate upper ocean response to typhoons, focusing on rightward bias (RWB) which means an appearance of an intensified sea surface cooling to the right side of the typhoon track. The model has 26-stratified levels and a flat bottom (1000 m), covering a rectangular domain of about 3,060 km×3,300 km with four open boundaries. The sea water is forced by an atmospheric pressure and a gradient wind of the typhoon. The model well reproduces the RWB in previous observations and theoretical analyses. For the fast moving typhoon (FMT) (-8m/sec), the model shows that in the mixed layer (ML), the RWB in the SST noticeably appears clearly illustrating the coupling between inertial motion and wind stress, but in the subsurface layer (-100m), the RWB does not emerge since a cyclonic current field (CCF) caused by wind stress curl is primarily dominant. For the slowly moving typhoon (SMT) (-3m/sec), however, the RWB does not emerge because the coupling is weakened and the CCF is rather predominant even in the ML. In the model, we conclude that the RWB noticeably emerges in the FMT but does not emerge in the SMT related to predominance of CCF.