• Journal of the Korea Convergence Society
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• v.13 no.2
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• pp.39-46
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• 2022

The purpose of this study is to determine the effect of a convergence approach, which applies both home environment modification applied with assistive technology and task-oriented intervention using a fall safety checklist, on the fall efficacy and activity level of stroke patients. 41 persons with stroke(21 experimental groups and 20 control groups) were divided into experimental and control groups. The experimental group was applied environmental modification and the task-oriented intervention using the fall safety checklist for 4 weeks. The control group was provided only the environmental modification. Before and after the intervention, the Korean Activity Card Sort (KACS) and the Korean Falls Efficacy Scale-Korean version (FES-K) were used for evaluation. There was no significant difference in fall efficacy and activity level change between the experimental group and the control group. Both the experimental group and the control group significantly improved the fall efficacy and activity level after the intervention. By applying the results of this study to the clinical field, it will be possible to support stroke patients to live safely and actively participate in the community.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.6
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• pp.311-319
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• 2019

The number of aged bridges is increasing so that bridges over 30 years old account for about 11% of all bridges. Consequently, the development of a seismic performance evaluation method that considers the effects of ageing is essential for a seismic retrofitting process for improvement of the seismic safety of existing old bridges. Assessment of the damage situation of bridges after the recent earthquakes in Korea has been limited to the bearings, anchor, and concrete mortar on piers. The purpose of this study is to evaluate the seismic responses of PSC box girder bridges by considering the ageing effect of rubber bearings (RBs) and lead-rubber bearings (LRBs). The modification factor proposed by AASHTO is used to take into account the ageing effect in the bearings. PSC box girder bridges with RBs and LRBs were 3D modeled and analyzed with the OpenSEES program. In order to evaluate the ageing effect of RBs and LRBs, 40 near fault and 40 far field records were used as the input earthquakes. When considering the effect of ageing, the displacement responses and shear forces of bridge bearings (RBs and LRBs) were found to increase mostly under the analytical conditions. It was shown that the effect of ageing is greater in the case of RBs than in the case of LRBs.

• Tribology and Lubricants
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• v.20 no.5
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• pp.237-244
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• 2004

Micro/nano tribological characteristics of PTFE coating films were experimentally studied. PTFE (polytetrafluoroethylene) modified polyethylene and low molecular weight PTFE were used as a coating materials. These films were deposited on Si-wafer (100) by IBAD (ion beam assisted deposition) method. The Ar ion beam sputtering was performed to change the surface topography of films using a hollow cathode ion gun under different Ar ion dose conditions in a vacuum chamber. Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribotester, SPM (scanning probe microscope), contact anglemeter and profilometer, respectively. The durability of the films were measured with macro tribotester. Results showed that the PTFE coating surfaces were converted to hydrophobic. The water contact angle of coated surfaces and surface roughness increased with the coating thickness. Adhesion and friction in micro and nano scale were governed by magnitude of normal load in soft material such as PTFE films. As the increase of sputtering time on low molecular weight PTFE films, the surface roughness was increased and nano adhesion and friction were decreased. The nano tribological characteristics of surfaces are mainly improved by chemical modification such as PTFE coating and given a synergy effect by the physical modification such as topographic modification.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1030-1033
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• 2004

We herewith report for the effect of dielectric surface modification on the electrical characteristics of organic thin-film transistors (OTFTs). The kist-jm-1 as an organic molecule for the surface modification is deposited onto the surface of zirconium oxide ($ZrO_2$) gate dielectric layer. The OTFTs are elaborated on the flexible plastic substrates through 4-level mask process to yield a simple fabrication process. In this work, we also have examined the dependence of electrical performance on the interface surface state of gate dielectric/pentacene, which may be modified by chemical properties in the gate dielectric surface.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.123-137
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• 1998

The finite deformation with self contact problem of C. V. joint boots is analysed by using the implicit finite element code ABAQUS/Standard. It is shown that analysis results have a good agreement with experimental ones to the degree of maximum rotation angle. As an application of design modification, the effects of thickness change of the rounded part of boot model on the bending and the contact situation of deformed geometry are investigated. In this paper, the effect of the design modification in the end on the leakage is examined using 2-D finite element simulation. To solve the leakage problem of grease, the length of the small end is enlarged. From this study, it is confirmed that we can save the cost and time by applying FEM techniques to analyze and design the boot model.

• The KSFM Journal of Fluid Machinery
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• v.12 no.1
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• pp.22-27
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• 2009

The important problems that arise in the design and performance of the axial flow turbine are the prediction and control of secondary flows. Some progresses have been made on understanding flow conditions that occur when the inlet endwall boundary layer separates at the point in the endwall and rolls up into the horseshoe vortex. And the flows though an axial turbine tend to be extremely complex due to its inherent unsteady and viscous phenomena. The passing wakes generated from the trailing edge of the stator make an interaction with the rotor. Unsteady flow should be considered rotor/stator interactions. The main purpose of this research is control of secondary flow and improvement efficiency in turbine by leading edge modification in unsteady state. When the wake from the stator ran into the modified leading edge of the rotor, the leading edge generated the weak pressure fluctuation by complex passage flows. In conclusion, leading edge modification(bulb2) results in the reduced total pressure loss in the flow field.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.663-667
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• 2005

Surface modified carbon nanotubes were applied into the epoxy composites to investigate its tribological property. Carbon nanotubes reinforced epoxy composites were fabricated by casting. Effects to the tribological property of loading concentrations and types of surface modification of carbon nanotubes were investigated under sliding condition using linear reciprocal sliding wear tester. The results show that the small amount of carbon nanotubes into the epoxy exhibited lower weight loss than the pure epoxy. It is concluded that the effect of an enormous aspect ratio of carbon nanotubes surface area which wider than conventional fillers that react as interface for stress transfer. As increased the contents of carbon nanotubes, the weight loss from the wear test was reduced. And the surface modified carbon nanotubes show better tribological property than as produced carbon nanotubes. It is due that a surface modification of carbon nanotubes increases the interfacial bonding between carbon nanotubes and epoxy matrix through chemical bonding. Changes in worn surface morphology are also observed by optical microscope and SEM for investigating wear behaviors. Carbon nanotubes in the epoxy matrix near the surface are exposed, because it becomes the lubricating working film on the worn surface. It reduces the friction and results in the lower surface roughness morphology in the epoxy matrix as increasing the contents of the carbon nanotubes.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.537-544
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• 2015

The effects of the modification of hybrid vehicle components on diesel exhaust emissions were investigated in this study. We examined the changes in exhaust emissions and the fuel consumption (FC) caused by the modification of generator (alternator) and motors. Exhaust emissions such as black carbon (BC), HC, $NO_X$ and $CO_2$ were measured not only in idle state but also on an actual urban road as well as on a chassis dynamometer. BC, $NO_X$ and HC emissions increased by 95%, 27% and 34% respectively when the generator charged the battery in the idle condition. BC and FC decreased in hybrid mode on the actual urban road partly because the motors were used to assist the diesel engine. In addition, the decreases in exhaust emissions and FC were also evident in the hybrid mode when the vehicle was tested on the chassis dynamometer.

• Carbon letters
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• v.25
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• pp.33-42
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• 2018

Activated carbon (AC) was modified by ammonium persulphate or nitric acid, respectively. AC and the modified materials were used as catalyst supports. The oxygen groups were introduced in the supports during the modifications. All the supports were characterized by $N_2$-physisorption, Raman, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and thermogravimetric analysis. Methanol synthesis catalysts were prepared through wet impregnation of copper nitrate and zinc nitrate on the supports followed by thermal decomposition. These catalysts were measured by the means of $N_2$-physisorption, X-ray diffraction, XPS, temperature programmed reduction and TEM tests. The catalytic performances of the prepared catalysts were compared with a commercial catalyst (CZA) in this work. The results showed that the methanol production rate of AC-CZ ($23mmol-CH_3OH/(g-Cu{\cdot}h)$) was higher, on Cu loading basis, than that of CZA ($9mmol-CH_3OH/(g-Cu{\cdot}h)$). We also found that the modification methods produced strong metal-support interactions leading to poor catalytic performance. AC without any modification can prompt the catalytic performance of the resulted catalyst.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1770-1774
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• 2000

Extended use of porcine blood in food ingredients depends on the decolorization of red blood cell concentrates and the modification of its functional properties. The purpose of this study is to compare the relative effect of cation ion exchanger for decolorization of porcine red blood globin. The globin extract is freeze-dried for determination of various functional properties, such as solubility, emulsion capability and foaming ability. Since the isoelectric point of blood globin is located at pH 6.8, which is the neutral pH ranges (6-8), so its functionalities are inferior around these pHs. This weakness has been the main reason, which limit the extended use of blood globin in food industry. Acetylation and succinylation of blood globin can be an alternative way to improve its functionalities. These results may provide new information to understand the decolorization mode by cation ion exchanger for the blood globin. With chemical, the functionalities of blood globin could be obviously improved. The above findings could enable food industry to extend the use of blood globin as a food ingredient.