• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.691-694
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• 1996

Two models of scratch testers developed recently are applied to the adhesion measurement of thin coatings. In both models the critical load is determined from the frictional irregularity when coated surface is broken in the scratching process. One model is effective for coatings thicker than 1m and the other for thin coatings down to $0.1\mu\textrm{m}$. The mechanism and the measurement principle of these testers are described. High sensitivity and good reproducibility of the measurement are attained primarily by the employment of new detection devices. These testers are even more useful for the quality control and the inspection of commercial products of coatings because only a small area of specimen is required for the test.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.7-12
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• 2011

In this paper, a laser scattering mechanism are designed to detect micro defects such as dent, scratch, pinhole, etc. Its influential parameters are experimentally selected and scattering patterns of micro defects have been analyzed for silicon wafer in solar cell. As a result of experiments, scattered lights are rather increased in wafer surface with micro defects, in comparison to no micro ones. Scattering parameters are optimally selected for obtaining robust and high quality laser scattering images of micro defects. It is shown that scattered light components are linearly increased according to the increase of micro defect sizes, and the depth of micro-defects give a large influence on optical deflection.

• Journal of Welding and Joining
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• v.3 no.2
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• pp.27-34
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• 1985

The mechanical properties and bonding mechanism of aluminum, copper and mild steel have been determined in cold pressure welding. The brittle cover layer to be established by scratch-brushing plays an important role in bond strength and has an influence on the threshold of deformation. The cold pressure welding was achieved at 54% of height reduction in A1-A1, 75% in Cu-Cu, 56% in Al-Cu, and 74% in Cu-steel. The height reduction at which the bond strength of weld interface was the same as the tensile strength of base metal should be over 76% in Al-Al, 82% in Cu-Cu, and 78% in Al-Cu.

• Korean Journal of Computational Design and Engineering
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• v.4 no.3
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• pp.224-237
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• 1999

This paper proposes a case-based approach to the conceptual design of mechanism, especially of the generation of design alternatives in function generation and motion transmission tasks. The aim of this work is to generate and provide various design alternatives by utilizing the previous design concepts underling in the existing design cases. The approach is based on the basic idea that the whole design concepts or sub-concepts extracted from different design cases can be merged to generate a variety of new design alternatives. The notion of virtual function generator is introduced to conceptualize and represent all possible underlying design concepts in the prior design cases. The virtual function generators are extracted in advance from the existing mechanism and serve as new conceptual building blocks for the synthesis of mechanism. Various design alternatives are generated basically by merging tow virtual function generators that partially match the specified function. By utilizing the design concepts that have been effectively used in the previous design cases. he proposed approach could efficiently produce more feasible design concepts than from-scratch ones. The approach proposed in this paper is illustrated with a design example.

• Korean Journal of Pharmacognosy
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• v.46 no.1
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• pp.59-64
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• 2015

Wound healing is a complex process that includes inflammation, granulation tissue formation, re-epithelialization, and remodeling. We reported previously that BuOH fraction from Hydnocarpi Semen (HS) crude extract exhibited wound healing activity in animal ulcer models. In this study, we investigated whether BuOH fraction activates keratinocyte and fibroblast via wound closure test and migration assay. In the scratch test, BuOH fraction accelerated the closure of a monolayer wound scratch at $100{\mu}g/mL$. After treatment with BuOH fraction for 18 h, keratinocytes showed a increase in migration at $25{\mu}g/mL$, whereas the migration of fibroblast increased significantly at $100{\mu}g/mL$ of BuOH fraction compared to control. The mechanism that the BuOH fraction of HS helps to promote healing by inflammation is possibly associated with the migration of keratinocyte and fibroblast.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.62-65
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• 2018

In the era of the 4th Industrial Revolution, IoT products of various and specialized fields are being developed and produced. Especially, the generation of the artificial intelligence, robotic technology Multilayer substrates and packaging technologies in the notebook, mobile device, display and semiconductor component industries are demanding the need for flexible materials along with miniaturization and thinning. To do this, this work use FCCL (Flexible Copper Clad Laminate), which is a flexible printed circuit board (PCB), to implement FPCB (Flexible PCB), COF (Chip on Film) Use is known to be essential. In this paper, I propose a transfer device which prevents the occurrence of scratches by analyzing the mechanism of wrinkle and scratch mechanism during the transfer process of thin film material in which the thickness increases while continuously moving in air or solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1853-1857
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• 2005

This paper reports on the development of the gripping system for automation of phone-camera module assembling. If manual assembling is shifted by automation, it will increase the fabrication speed and reduce the defective rate. In the gripping mechanism design, we needs self-adjustable passive mechanism that minimize the number of the parts. The self-adjusting system compensates the positioning errors that have been made in translations. And also we need gripper system that can be modules of parts. That makes it easy to change or repair the parts. The forces put on the objects is another considerable in the system. It must not cause dropping, breakage, scratch, and large deformation. So final target of this reaseach is how to develop the system that is speedy, small, simple, and safe

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2196-2204
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• 1996

The damage mechanism by the impact of steel ball on the soda-lime glass having a different surface roughness was investigated. An initiation and a propagation behavior of cracks formed by each impact velocity were quantitatively studied. A 4-point bending test was carried out to evaluate the remaining bending strength of a scratched soda-lime glass which impacted by the steel ball. As the surface roughness was increased, the shape of cracks became more irregular rather than those of the smooth specimens. The phenomenon of turning up in the wing of cone cracks occurred even at the lower velocity than the critical velocity caused the crushing. The threshold velocity of cracks initiation generally became lower than those of smooth specimen. An initiation and a propagation behavior of radial cracks had no relation with the direction of scratch on the surface. The remaning benidng strength of the scratched specimen according to impact velocity had no big difference compared with those of the smooth specimen.

• Journal of Mechanical Science and Technology
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• v.16 no.7
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• pp.911-918
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• 2002

The tribological performance of A1$_2$O$_3$/NiCr coating deposited on steel (SH45C) was investigated under lubrication. The parameters of sliding wear consist of normal load and coating thickness. Test result showed that there was no evidence of an improved bonding strength in the coating. However, the wear resistance of the A1$_2$O$_3$/NiCr coaling was significantly greater than that of the Al$_2$O$_3$ coating. It was eviclent that the residual stress for the A1$_2$O$_3$coating was higher than that of the A1$_2$O$_3$/NiCr coating from the Scratch test failure of coating. The bond coating played an important role in decreasing the residual stress. Also, it was found that the residual stress had d notable influence on the wear mechanism.

• Journal of Technology Innovation
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• v.8 no.1
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• pp.49-71
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• 2000

This paper looks at "network" aspects of research and development (R'||'&'||'D) with a special focus on small and medium (S'||'&'||'M) automotive part makers in Korea. It throws light on recent changes in the technological capability building mechanism of Korean automotive firms. The Korean automotive firms have mostly built up technological capability from scratch. It is widely acknowledged that they have benefited from two cooperative relations: namely (1) the close cooperative relationship with their own assemblers and (2) technical assistance from auto parts makers abroad. Too much emphasis on these two links can, however, keep us from understanding new developments. This paper argues that auto parts firms have diversified their networks for technological development. It is based on the analysis of the data drawn from the survey on technological development activities of small and medium sized firms, which was carried out by the Korea Federation of Small and Medium Business. Many automotive firms have recently increased joint R'||'&'||'D links with university and/or research institution while their reliance on foreign sources have decreased.