• Journal of the Korean Society for Precision Engineering
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• v.31 no.6
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• pp.513-519
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• 2014

For depth machining in die and mold, Electrical Discharge Machining (EDM) is used generally. To make deep hole and deep shape efficiently, cemented carbide endmill for depth machining is necessary. For this purpose, cemented carbide endmill was designed using design of experiment (DOE). To improve cutting performance, endmill was coated with multilayer surface treatment, TiAlCrSiN and TiAlCrN, for higher wear resistance. In order to evaluate the endmill, Transverse Rupture Strength (TRS) test was tried for investigating the relationship between surface treatment and strength in endmill body. Scratch test was also used for measuring adhesion force of each surface treatment. To evaluate hardness of surface treatment, Atomic Force Microscope (AFM) analysis was carried out. Wear test was executed for characteristics of each surface treatment in high temperature. Consequently, TiAlCrSiN was superior to the TiAlCrN coating in case of high temperature environment such as cutting.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.75-78
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• 2006

In case of contacts between semiconductor and metal in semiconductor circuits, they become unstable because of thermal budget. To prevent these problems, we use diffusion barrier that has a good thermal stability between metal and semiconductor. So we consider the diffusion barrier to prevent the increase of contact resistance between the interfaces of metals and semiconductors, and the increase of resistance and the reaction between the interfaces. In this paper we deposited tungsten boron carbon nitride (W-B-C-N) thin film on silicon substrate. The impurities of the $1000\;{\AA}-thick$ W-B-C-N thin films provide stuffing effect for preventing the inter-diffusion between metal thin films $(Cu-2000\;{\AA})$ and silicon during the high temperature $(700\~1000^{\circ}C)$ annealing process.

• Molecules and Cells
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• v.41 no.9
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• pp.853-867
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• 2018

As the most common type of endocrine malignancy, papillary thyroid cancer (PTC) accounts for 85-90% of all thyroid cancers. In this study, we presented the hypothesis that SDC4 gene silencing could effectively attenuate epithelial mesenchymal transition (EMT), and promote cell apoptosis via the $Wnt/{\beta}-catenin$ signaling pathway in human PTC cells. Bioinformatics methods were employed to screen the determined differential expression levels of SDC4 in PTC and adjacent normal samples. PTC tissues and adjacent normal tissues were prepared and their respective levels of SDC4 protein positive expression, in addition to the mRNA and protein levels of SDC4, $Wnt/{\beta}-catenin$ signaling pathway, EMT and apoptosis related genes were all detected accordingly. Flow cytometry was applied in order to detect cell cycle entry and apoptosis. Finally, analyses of PTC migration and invasion abilities were assessed by using a Transwell assay and scratch test. In PTC tissues, activated $Wnt/{\beta}-catenin$ signaling pathway, increased EMT and repressed cell apoptosis were determined. Moreover, the PTC K1 and TPC-1 cell lines exhibiting the highest SDC4 expression were selected for further experiments. In vitro experiments revealed that SDC4 gene silencing could suppress cell migration, invasion and EMT, while acting to promote the apoptosis of PTC cells by inhibiting the activation of the $Wnt/{\beta}-catenin$ signaling pathway. Besides, $si-{\beta}-catenin$ was observed to inhibit the promotion of PTC cell migration and invasion caused by SDC4 overexpression. Our study revealed that SDC4 gene silencing represses EMT, and enhances cell apoptosis by suppressing the activation of the $Wnt/{\beta}-catenin$ signaling pathway in human PTC.

• Journal of the Korean institute of surface engineering
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• v.49 no.6
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• pp.530-538
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• 2016

There is a close relationship between the performance and the heat generation of the electronic device. Heat generation causes a significant degradation of the durability and/or efficiency of the device. It is necessary to have an effective method to release the generated heat. Based on demands of the printed circuit board (PCB) manufacturing, it is necessary to develop a robust and reliable plating technique for substrates with high thermal conductivity, such as alumina ($Al_2O_3$), aluminium nitride (AlN), and silicon nitride ($Si_3N_4$). In this study, the plating of metal layers on an insulating silicon nitride ($Si_3N_4$) ceramic substrate was developed. We formed a Pd-$TiO_2$ adhesion layer and used APTES(3-Aminopropyltriethoxysilane) to form OH groups on the surface and adhere the metal layer on the insulating $Si_3N_4$ substrate. We used an electroless Ni plating without sensitization/activation process, as Pd particles were nucleated on the $TiO_2$ layer. The electrical resistivity of Ni and Cu layers is $7.27{\times}10^{-5}$ and $1.32{\times}10^{-6}ohm-cm$ by 4 point prober, respectively. The adhesion strength is 2.506 N by scratch test.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.524-531
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• 2018

Background: Fermented black ginseng (FBG) is produced through several cycles of steam treatment of raw ginseng, at which point its color turns black. During this process, the original ginsenoside components of raw ginseng (e.g., Re, Rg1, Rb1, Rc, and Rb2) are altered, and less-polar ginsenosides are generated (e.g., Rg3, Rg5, Rk1, and Rh4). The aim of this study was to determine the effect of FBG on wound healing. Methods: The effects of FBG on tube formation and on scratch wound healing were measured using human umbilical vein endothelial cells (HUVECs) and HaCaT cells, respectively. Protein phosphorylation of mitogen-activated protein kinase was evaluated via Western blotting. Finally, the wound-healing effects of FBG were assessed using an experimental cutaneous wounds model in mice. Results and Conclusion: The results showed that FBG enhanced the tube formation in HUVECs and migration in HaCaT cells. Western blot analysis revealed that FBG stimulated the phosphorylation of p38 and extracellular signal-regulated kinase in HaCaT cells. Moreover, mice treated with $25{\mu}g/mL$ of FBG exhibited faster wound closure than the control mice did in the experimental cutaneous wounds model in mice.

• The Journal of Korean Association of Computer Education
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• v.15 no.2
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• pp.1-8
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• 2012

General form of the programing education is finding and realizing algorithm to solve problems faster and more efficiently. In other words, it is based on convergent thinking. However, the programming education must have different characteristics to education targets. For elementary school students, it is needed to provide various experience-centered investigation environments. They should learn how to find the most efficient problem solving method by themselves. This study had adopted divergent thinking strategy where divergent thinking and convergent thinking can be repeated at the same time to suit a programming education with great importance of convergent thinking to elementary school leaners, and analyzed its effects. This study was applied to 5th graders, and 12 times of experimental measure classes were conducted by dividing them into the control group that conducted general programming class and the experimental group that conducted a programming class including divergent thinking of CPS model. As a result, CPS model had significant effect on the subordinate elements of creative problem solving skills, self-assurance, independence, and divergent thinking.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.969-972
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• 2008

This study investigated the effect of the fundamental condition such as release agent, form conditions and types to the surface of concrete with aluminum form on the various temperatures. On the observation with the naked eyes, coated plywood and aluminum form without a scratch showed similar result, and the surface quality of the concrete with aluminum form was gradually decreased corresponding to the increase of the temperature.For the surface roughness, there is no remarkable tendency according to the temperature. However, the difference in accordance with release agent occurred.As void on the surface corresponding to the various temperature, the micro voids ranged $0.1{\sim}1mm$ were increased corresponding to the increasing temperature, so it was confirmed that the chemical reaction wae accelerated. And the voids of the other range also increased. the fundamental condition such as release agent, form conditions and types

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.325-327
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• 2015

Startup in the aging society is much harder than finding employment. However, we did an experimental research that the elderly are able to develop in the field of IoT via this education. Through this IT startup education, those people who can do develop and implement and they are able to start new business by develop new item. Installing education between hardware and software about Arduino and Scratch's methods have great effect on IT startup education for the elderly before solving problem which have existing programming education. While the IT startup education through IoT is more difficult subject compared to general education subject, this paper shows an easily accessible research outcome for the elderly through startup education. This paper proved that practical uses through the results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.114-114
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• 2008

반도체 device의 성능을 향상시키기 위하여 패턴은 더욱 더 고 집적화 되고 배선 또한 다층배선 구조를 가지게 되었으며 요구되는 선폭 또한 더욱 미세화 되어 CMP 공정이 도입되게 되었다. 이러한 CMP 공정에 사용되는 소모품으로는 크게 세 가지의 중요한 부분으로 나눌 수 있다. 그것은 slurry와 pad, conditioner이다. 그중에 pad conditioning 공정은 CMP 공정시 pad의 마모에 따라 감소하는 removal rate(RR)값을 회복시키기 위한 공정으로 마모된 pad의 표면을 활성화 시켜주는 중요한 공정이다. 하지만 pad conditioning 공정을 장시간 진행하게 되면 conditioner 표면에 오염물이 발생하게 되며, 오염물로 인하여 wafer표면에 scratch 및 defect을 발생시키는 원인이 될 수 있다. 이러한 문제점을 보완하기 위하여 conditioner의 표면을 변화시켜 공정중의 오염이 발생하지 않도록 하는 것이 중요하다. 본 논문에서는 oxide CMP 실험을 통하여 conditioner표면에 오염물이 발생함을 확인하였으며 energy dispersive spectroscopy(EDS) 분석을 통하여 주오염물의 성분이 oxide slurry중 silica임을 확인하였다. Conditioner의 표면을 소수성으로 만들기 위하여 self assembled monolayer(SAM) 방법을 이용하여 표면에 코팅을 하였으며, 소수성 박막이 코팅된 conditioner와 코팅되지 않은 conditioner의 비교 실험을 통하여 오염 정도를 비교하였다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.5
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• pp.191-195
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• 2002

Chemical mechanical Polishing (CMP) process is widely used for the global planarization of inter-metal dielectric (IMD) layer and inter-layer dielectric (ILD) for deep sub-micron technology. However, as the IMD and ILD layer gets thinner, defects such as micro-scratch lead to severe circuit failure, which affect yield. In this paper, for the improvement of CMP process, deionized water (DIW) pressure, purified $N_2$ ($PN_2$) gas, point of use (POU) slurry filler and high spray bar (HSB) were installed. Our experimental results show that DW pressure and P$N_2$ gas factors were not related with removal rate, but edge hot-spot of patterned wafer had a serious relation. Also, the filter installation in CMP polisher could reduce defects after CMP process, it is shown that slurry filter plays an important role in determining consumable pad lifetime. The filter lifetime is dominated by the defects. However, the slurry filter is impossible to prevent defect-causing particles perfectly. Thus, we suggest that it is necessary to install the high spray bar of de-ionized water (DIW) with high pressure, to overcome the weak-point of slurry filter Finally, we could expect the improvements of throughput, yield and stability in the ULSI fabrication process.