• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1128-1132
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• 1998

We have investigated the relationship between the polar anchoring energy and the surface order parameter in nematic liquid crystal (NLC), 4-n-pentyl-4-cyanobiphenyl (5CB), on the two kinds of the weakly rubbed polyimide (PI) surfaces. The observed polar anchoring energy of 5CB is approximately 2${\times}10^{-4}(J/m^2$) and then increases with increasing the rubbing strength (RS) on weakly rubbed surface (RS=57mm) with side chain at $30^{\circ}C$; same results are obtained on weakly rubbed PI surface without side chain. The surface order parameter of 5CB on rubbed PI surfaces increases with increasing the RS at a weak rubbing region. The surface order parameter of 5CB is strongly related to the characteristics of PI material. Consequently, we suggest that the polar anchoring energy of NLC is strongly attributed to the surface order parameter on rubbed PI surfaces.

• Textile Coloration and Finishing
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• v.16 no.5
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• pp.35-41
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• 2004

Poly(ethylene terephthalate), polyimide(Kapton), and polypropylene surfaces were modified with argon low temperature plasma by RF glow discharge at 240m Torr, 40W to investigate the surface morphological changes due to the plasma treatment using atomic force microscopy(AFM). Analysis of the AFM images and Ra(average roughness) revealed that the plasma treatment resulted in significant ablation on the surfaces. The morphological changes and surface roughness, however, were different depending on material characteristics such as heat stability, presence of amorphous region, swelling phenomenon, and molecular structure of repeating unit. It was assumed that polypropylene due to its tertiary hydrogen was ablated easily compared to poly(ethylene terephthalate), and that polyimide was more resistant to the ablation than PET due to rigid skeleton of imide and stable phenyl ring structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.477-480
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• 2003

We investigated the electro-optical (EO) performances of the super twisted nematic liquid crystal display (STN-LCD) on the polyimide (PI) surface using polymer film. Monodomain alignment of the plastic STN-LCD can be observed. A stable voltage-transmittance (V-T) curve of the plastic STN-LCD was observed on the polyimide (PI) surfaces using polymer film. Also, a faster response time for the plastic STN-LCD on the polyimide (PI) surfaces using polymer film can be achieved. However, the transmittance of the plastic STN-LCD on the polyimide (PI) surfaces using polymer film decreased greatly as cell gap decreases.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.374-381
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• 2001

Surface roughness plays a significant role in friction, wear, and lubrication in machine components. Most engineering surfaces have tile nogaussian height distrubution. So, in this study, elastic-plastic contact simulations are conducted for not only gaussian surfaces but also nongaussian surfaces. Nongaussian rough surface considering the kurtosis is generated numerically. The contact simulation model takes into account the plastic deformation behaviors of asperities by setting a celing on their contact pressure at material hardness value. It will be shown that the performace variables such as real contact area fraction, plastic area fraction and average gap are sensitive to the characteristics of surface geometry according to kurtosis.

• IMMUNE NETWORK
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• v.20 no.6
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• pp.44.1-44.19
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• 2020

The human body is continuously threatened by pathogens, and the immune system must maintain a balance between fighting infection and becoming over-activated. Mucosal surfaces cover several anatomically diverse organs throughout the body, such as the respiratory and gastrointestinal tracts, and are directly exposed to the external environment. Various pathogens invade the body through mucosal surfaces, making the mucosa the frontline of immune defense. The immune systems of various mucosal tissues display distinctive features that reflect the tissues' anatomical and functional characteristics. This review discusses the cellular components that constitute the respiratory and gastrointestinal tracts; in particular, it highlights the complex interactions between epithelial and immune cells to induce Ag-specific immune responses in the lung and gut. This information on mucosal immunity may facilitate understanding of the defense mechanisms against infectious agents that invade mucosal surfaces, such as severe acute respiratory syndrome coronavirus 2, and provide insight into effective vaccine development.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.26-34
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• 2008

This study focus on segmentation process that classifies road surfaces into 5 different categories, dry, wet water, icy, and snowy surfaces by analyzing asphalt-paved road images taken in daylight. By using the polarization coefficients, the proportions of horizontally polarized components to vertically polarized components, regions with over 1.3 polarization coefficients are classified as wet surfaces. Except for wet surfaces, the decision process a lies time-frequency analysis to other parts by using the third order wavelet packet transform. In addition, by using the average frequency characteristics of dry and icy surfaces from image templates, decide which is closer to a test image, and finally identify dry and icy surfaces. It is confirmed that the reposed estimation and segmentation of recognition on various images. This can be interpreted as an indication that image-only mad surface condition supervision is probable.

• Korean Journal of Computational Design and Engineering
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• v.1 no.3
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• pp.189-202
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• 1996

Complex geometric shapes can be defined simply and efficiently by combining and operating various surface primitives. These primitives and their intersection curves are used in finite element mesh generation to form an easy and intuitive procedure for finite element modelling of curved surfaces. This paper proposes techniques of automatic mesh generation on surface primitives with arbitrarily shaped boundaries and control curves, which may be created by surface to surface intersection. A method of automatic mesh generation on plane, which was previously developed by the author, has been modified for application to the surface mesh generation. Owing to the mesh generation-wise differences between planes and surfaces, the surfaces should be transformed into conceptual plane so that the modified plane mesh generation method can be applied. Surface development, mapping and mesh reconstruction are the key techniques suggested in this paper. The selection of the technique to apply can be determined automatically on the basis of the developability, existence of singularity and other characteristics of the surfaces on which the mesh is to be generated. The suggested techniques were implemented into parts of mesh generation functions of the finite element software, MacTran. Their validity and practicality were manifested by the actual use of this software.

• Korean Institute of Interior Design Journal
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• v.13 no.2
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• pp.64-71
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• 2004

This study attempts to clarify inter-relationship between design expression in the surface of contemporary multi-family housing and physical trends in this digital age. The study examines characteristics of housing design influenced from new digital technology in the forms of metaphor such as dematerialization, fluidity and mobility. Currently constructed multi-family housing in Europe after 1990 has been analyzed to find digital reflections in the surfaces. As a conclusion, findings are as follows; In this digital age, a house is considered as a base in the forms of boxes and containers to network to outer worlds. In a complex of multi-family housing, public spaces move to the inside and become parts of private domain. Therefore, a house directly faces a street/outer world without transitional areas and devices. The facades of housing become delicate skins to control private domain in the inside and the world in the outside. In this digital age, the surfaces of housing are designed by ways of wrapping and screening. Printing and mapping methods are used to surface design because they are manipulative and flexible methods in design like graphic design. Screening devices using louvers and shutters are powerful tools to make random and unpredictable images. If units of a louver and a shutter were pixels, a whole surface would be a digital screen. In such assumption, the facade of buildings reflects digital screen to interface while the louvers in operation reflect clicking to network. As a conclusion, design expression in surfaces in-between of multi-family housing is a metaphor of digital mechanism.

• KCID journal
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• v.18 no.2
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• pp.3-14
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• 2011

Increased impervious surfaces alter stream hydrology resulting in lower flows during droughts and higher peak flows during floods. Not only urban area but also rural area has been expanded impervious surfaces because of increasing of greenhouses. The main objective of this study was to evaluate the performance of the AnnAGNPS (Annualized Non-Point Source Pollution Model) on the surface runoff characteristics of the Daejeon-Stream watershed, and to predict the hydrological effects due to increasing of impervious surfaces. The model parameters were obtained from the geographical information system (GIS) databases, and additional parameters calibrated with the observed data. The model was calibrated by using 2004 of the runoff data and validated by using 2002 data obtained from WAMIS (Water Management Information System) to compare the simulated results for the study watershed. R2 values and efficiency index (EI) between observed and simulated runoff were 0.78 and 0.80, respectively at the calibration period. In this study, expanding of impervious surfaces such as greenhouses caused increasing of surface runoff, but caused decreasing of total nitrogen and total phosphorus loads.

• Restorative Dentistry and Endodontics
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• v.42 no.1
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• pp.39-47
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• 2017

Objectives: Although the coating of surface sealants to dental composite resin may potentially reduce bacterial adhesion, there seems to be little information regarding this issue. This preliminary in vitro study investigated the adhesion of Streptococcus mutans (S. mutans) on the dental composite resins coated with three commercial surface sealants. Materials and Methods: Composite resin (Filtek Z250) discs (8 mm in diameter, 1 mm in thickness) were fabricated in a mold covered with a Mylar strip (control). In group PoGo, the surfaces were polished with PoGo. In groups PS, OG, and FP, the surfaces polished with PoGo were coated with the corresponding surface sealants (PermaSeal, PS; OptiGuard, OG; Fortify Plus, FP). The surfaces of the materials and S. mutans cells were characterized by various methods. S. mutans adhesion to the surfaces was quantitatively evaluated using flow cytometry (n = 9). Results: Group OG achieved the lowest water contact angle among all groups tested (p < 0.001). The cell surface of S. mutans tested showed hydrophobic characteristics. Group PoGo exhibited the greatest bacterial adhesion among all groups tested (p < 0.001). The sealant-coated groups showed statistically similar (groups PS and FP, p > 0.05) or significantly lower (group OG, p < 0.001) bacterial adhesion when compared with the control group. Conclusions: The application of the surface sealants significantly reduced S. mutans adhesion to the composite resin polished with the PoGo.