• Elastomers and Composites
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• v.55 no.4
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• pp.339-346
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• 2020

We functionalized a wear-resistant carbon-based MoS2 filler to solve its limited wear condition problem. The filler exhibits excellent lubricative properties. The surface modification of MoS2 was carried out using a (3-glycidyloxypropyl)trimethoxysilane (GPTMS) silane coupling agent to improve the low compatibility and dispersibility of the filler that generally degrade the performance of composites. A silane coupling agent was employed for the functionalization of MoS2, and its effect on the wear resistance of MoS2/Polyamide-6,6 was investigated. The silanization of MoS2 was identified by contact angle analysis and Fourier-transform infrared, energy dispersive X-ray, and X-ray photoelectron spectroscopies. The wear resistance of the composite was found to be improved significantly by the surface functionalization of MoS2.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.161.6-161
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• 2001

Confocal scanning microscopy (CSM) has an important role as the three-dimensional profiler. An image distribution can be reconstructed by a correlation analysis of spots with the bandwidth of radio frequency. But it is a serious problem for the high performance to align the optical components. Especially, the parasitic motion of focus on the detector gives rise to the fatal distortion of an image profile named the extinction effect while using acousto-optical(AO) deflector. An image profile can be regenerated in CSM with many advantages of non-contact, high speed and high resolution comparatively. In addition to the axial response of the primary focus, the lateral movement of it gives a necessity of the unitary lens to the scanning system. While using the beam deflector, the pupil of beam may be fixed at the nominal position. Furthermore, the use of a deflector may result in ...

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.77-78
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• 2002

A regression formula including the inlet film thickness as the parameter for the starvation factor in EHL condition is obtained by numerical analysis with Elord‘s cavitation algorithm. In addition, an apparatus for starved film thickness measurement by use of the white light interferometry is developed in order to verify the proposed regression formula. From observation results by this apparatus, the proposed regression formula can predict the reduction of central film thickness caused by starvation in a ball-plate contact with an uncertainty up to 10%

• Progress in Superconductivity and Cryogenics
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• v.12 no.2
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• pp.5-8
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• 2010

In this study, the effect of bending strain on the transport property and critical current of lap and butt-jointed (non-laminated) BSCCO tapes has been investigated. The samples were joined using a mechanically controlled jointing procedure. To achieve a uniform thickness at the joint a single point loading contact has been devised. GFRP mandrels with different bending radii which support the sample during bending have been used. $I_c$ have been measured at 77 K and self field. In the case of easy bending test for jointed BSCCO tapes, sudden degradation of $I_c$ is caused by the local strain concentration due to non uniform deformation at the edge parts of the joint. In the case of hard bending test of jointed BSCCO tapes transverse macroscopic crack at specific subsection caused a large $I_c$ degradation. The transport property of jointed BSCCO tapes in each bending mode was discussed with the damage morphology occurred.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.1
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• pp.40-42
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• 2002

TiO$_2$/Fe$_2$O$_3$composite thin films were prepared on common glass substrates by sol-gel processing and dip-drawing method. The effect of Fe$_2$O$_3$content on the photocatalytic and hydrophilic properties of composite films was studied. The results indicate that the photocatalytic activities of composite TiO$_2$films are superior to that of pure TiO$_2$film, and the film containing 0.5% Fe$_2$O$_3$has the best photocatalytic activity. The hydrophilicity is difference with variant Fe$_2$O$_3$content, the films containing 0.05% ~0.1% Fe$_2$O$_3$have the best hydrophilicity and their contact angles are 0。.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.72-76
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• 2023

The mobile card system used for mobile access control is connected to the door lock mounted on the door, enabling non-contact control. The RSSI (Received Signal Strength Indicator) of the BLE (Bluetooth Low Energy) communication packet used here can help to know the direction and distance of the mobile device. In this study, the desirable access control distance was calculated and implemented by setting the RSSI of the transmitter of the BLE packet used in mobile access control and processing the RSSI of the receiver.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.1
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• pp.33-39
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• 2023

In this study, the effect of mixing condition of raw material powders possessing various particle size and particle size distribution on thermite reaction efficiency was investigated. When fine raw powders are used, rather the reaction yield tends to decrease due to agglomeration. In contrast, coarse raw powders make deteriorate the contact area between raw material powders containing Al reducing agent. To ensure the optimal thermite reaction efficiency, it is required to optimize a mixture condition of raw material powders prior to thermite reaction. From the current experiment, the maximum thermite reaction efficiency is 77%, which came from Nb₂O₅ + NiO +Al mixtures with size distribution from 9.25 to 22.63 ㎛.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.6
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• pp.412-421
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• 2023

As the demand for mechatronic systems and high performance increases in the machinery industry, the importance of improving friction characteristics is emphasized. During relative movement of objects, friction and wear occur on two surfaces in contact, and various methods are being designed to increase the lifespan and energy efficiency of machines. The energy increase effect using lubricants is a well-known method. In this study, a micro-sized rectangular grid pattern was produced by applying a precise micro-pattern photo lithography process. Rectangular grid patterns of the same shape and friction behavior according to the size of the pattern were produced in convex and concave shapes, and the tribological characteristics of each were analyzed.

• Structural Engineering and Mechanics
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• v.88 no.6
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• pp.609-623
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• 2023

The objective of this study is to investigate the distribution of von Mises stress, peeling stress, and shear stress in the adhesive layer used to bond two composite panels, considering various parameters using a three-dimensional finite element method. The stiffness of the materials and the effect of the stacking order on the amount of load transferred to the adhesive layer were examined to determine which type of laminate generates less stress at the bond line. The study analyzed six different stacking sequences, all with a common first layer in contact with the adhesive and a 0° orientation. Additionally, the impact of using hybrid composites on reducing bond line stress was investigated.

• Archives of Metallurgy and Materials
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• v.64 no.3
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• pp.931-934
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• 2019

Al-CuO is a thermite material exhibiting the exothermic reaction only when aluminum melts. For wide spread of its application, the reaction temperature needs to be reduced in addition to the enhancement of total reaction energy. In the present study, a thermite nanocomposite with a large contact area between Al and CuO was fabricated in order to lower the exothermic reaction temperature and to improve the reactivity. A cryomilling process was performed to achieve the nanostructure, and the effect of composition on the microstructure and its reactivity was studied in detail. The microstructure was characterized using SEM and XRD, and the thermal property was analyzed using DSC. The results show that as the molar ratio between Al and CuO varies, the fraction of uniform nanocomposite structure was changed affecting the exothermic reaction characteristics.