• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.538-543
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• 2008

Recently a nano-scale diamond is possible to manufacture forms of powder(below 100 nm) by new processing of explosion or deposition method. Using a sintering of nano-scale diamond is possible to manufacture of grinding tools. We have need of a processing development of coated uniformly inorganic to prevent an abnormal grain growth of nano-crystal and bonding obstacle caused by sintering process. This paper, in order to improve the sintering property of nano-scale diamond, we coated ZnO thin films(thickness: $20{\sim}30\;nm$) in a vacuum by ALD(atomic layer deposition) Economically, in order to deposit ZnO all over the surface of nano-scale diamond powder, we used a new modified fluidized bed processing replaced mechanical vibration effect or fluidized bed reactor which utilized diamond floating owing to pressure of pulse(or purge) processing after inserted diamond powders in quartz tube(L: 20 mm) then closed quartz tube by porosity glass filter. We deposited ZnO thin films by ALD in closed both sides of quartz tube by porosity glass filter by ALD(precursor: DEZn($C_4H_{10}Zn$), reaction gas: $H_2O$) at $10^{\circ}C$(in canister). Processing procedure and injection time of reaction materials set up DEZn pulse-0.1 sec, DEZn purge-20 sec, $H_2O$ pulse-0.1 sec, $H_2O$ purge-40 sec and we put in operation repetitive 100 cycles(1 cycle is 4 steps) We confirmed microstructure of diamond powder and diamond powder doped ZnO thin film by TEM(transmission electron microscope) Through TEM analysis, we confirmed that diamond powder diameter was some $70{\sim}120\;nm$ and shape was tetragonal, hexagonal, etc before ALD. We confirmed that diameter of diamond powders doped ZnO thin film was some $70{\sim}120\;nm$ and uniform ZnO(thickness: $20{\sim}30\;nm$) thin film was successfully deposited on diamond powder surface according to brightness difference between diamond powder and ZnO.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.240-253
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• 2019

Archaeological heritages are precious cultural relics and public assets that must be preserved, conserved, and shared with people all over the world. Investigating archaeological heritage is valuable and plays an important role for the public good; our ancestors' cultures can be restored, and it helps with developing a clear understanding of the cultural and social aspects of a historical period as well as teaches about historical factors unreported in the literature. One of the most basic and important conditions necessary for recognizing the value and importance of archaeological heritage investigation, expertise, and quality improvement is to establish detailed criteria for investigation services and the qualification examination of archaeological heritage. Observation of detailed criteria and the qualification examination of archaeological heritage can partially demonstrate society's recognition of strengthening transparency, public property, and the objectivity of the investigation of archaeological heritage. However, the detailed criteria for investigation services and the qualification examination of archaeological heritage currently implemented as administrative rules are neither followed by all institutes in the public and private sectors nor the government. Thus, there are serious problems in terms of the effectiveness and stability of institutions. The detailed criteria for the qualification examination breach the principle of statutory reservation, the principle of statutory regulation, and regulations on the announcement and management of orders and rules. Non-compliance with compensation criteria for investigation services or with detailed criteria for the qualification examination of archaeological heritage will be one of the reasons for the failure of the investigation foundation for archaeological heritage in the future. That is, it will result in the expansion, reproduction, and repetition of a vicious cycle of conflict between developers, who are the decision-makers responsible for selecting an investigating organization for archaeological heritage and determining the cost, and investigating organizations. This includes the impractical shortening of investigation periods and reducing costs by developers, distrust of the values and the importance of investigations of archaeological heritage, a decrease in quality, accidents caused by a lack of safety, a lack of occupational ethics, and non-recruitment of new experts, etc. Therefore, it is necessary to change the structure from a vicious cycle to a virtuous cycle, and promote the enactment of regulations that will ensure effectiveness and stability in the process of attaining the goals of the institution and application of the institution, as well as the continuous advancement of work to fill the gaps with reality.

• Journal of Welding and Joining
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• v.30 no.1
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• pp.64-71
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• 2012

The characteristics of high heat input (342kJ/cm) EG (Electro Gas Arc) welded joint of EH36-TM steel has been investigated. The weld metal microstructure consisted of fine acicular ferrite (AF), a little volume of polygonal ferrite (PF) and grain boundary ferrite (GBF). Charpy impact test results of the weld metal and heat affected zone (HAZ) met the requirement of classification rule (Min. 34J at $-20^{\circ}C$). In order to evaluate the relationship between the impact toughness property and the grain size of HAZ, the austenite grain size of HAZ was measured. The prior austenite grain size in Fusion line (F.L+0.1 mm) was about $350{\mu}m$. The grain size in F.L+1.5 mm was measured to be less than $30{\mu}m$ and this region was identified as being included in FGHAZ(Fine Grain HAZ). It is seen that as the austenite grain size decreases, the size of GBF, FSP (Ferrite Side Plate) become smaller and the impact toughness of HAZ increases. Therefore, the CGHAZ was considered to be area up to 1.3mm away from the fusion line. Results of TEM replica analysis for a welded joint implied that very small size ($0.8\sim1.2{\mu}m$) oxygen inclusions played a role of forming fine acicular ferrite in the weld metal. A large amount of (Ti, Mn, Al)xOy oxygen inclusions dispersed, and oxides density was measured to be 4,600-5,300 (ea/mm2). During the welding thermal cycle, the area near a fusion line was reheated to temperature exceeding $1400^{\circ}C$. However, the nitrides and carbides were not completely dissolved near the fusion line because of rapid heating and cooling rate. Instead, they might grow during the cooling process. TiC precipitates of about 50 ~ 100nm size dispersed near the fusion line.

• Composites Research
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• v.31 no.2
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• pp.63-68
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• 2018

Thermoplastic composite has been limitedly used in high performance aerospace industry due to relatively low mechanical properties even though it has various advantages. But, thermoplastic aromatic polymer composite has recently been researched and utilized much. In this study, PEEK and PPS neat resin film as representative thermoplastic aromatic polymer were processed through continuous heating, cooling and reheating cycle. Property change such as glass transition temperature and melting temperature were identified and crystallinity variation by different cooling rate were evaluated. In the first (heating) run, polymer specimens were kept for 5 minutes at higher temperature than melting point to remove previous thermal history, and crystallization reaction was controlled by adjusting cooling rate to 2, 5, 10, 20 and $40^{\circ}C/minute$ in the second (cooling) run. In the third (heating) run, specimen crystallinity were verified by measuring the melting enthalpy. The initial specimens containing high portion of amorphous structure exhibited cold crystallization and clear glass transition in the first run whereas they did not show in the third run due to the increase of crystalline structure portion. As cooling rate decreases through the second cooling run, the crystallinity of the specimen increased. PEEK polymer had 21.9~39.3% crystallinity depending on cooling rate change whereas PPS polymer showed 29.1~31.2%.

• Spatial Information Research
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• v.23 no.1
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• pp.41-48
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• 2015

BIM Technology contains data from the life cycle of facility through 3D modeling. For these, one building products the huge file because of massive data. One of them is IFC which is the standard format, and there are issues that large scale data processing based on geometry and property information of object. It increases the rendering speed and constitutes the graphic card, so large scale data is inefficient for screen visualization to user. The light weighting of large scale BIM data has to solve for process and quality of program essentially. This paper has been searched and confirmed about light weight techniques from domestic and abroad researches. To control and visualize the large scale BIM data effectively, we proposed and verified the technique which is able to optimize the BIM character. For operating the large scale data of facility on web based GIS platform, the quality of screen switch from user phase and the effective memory operation were secured.

• Environmental Mutagens and Carcinogens
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• v.24 no.2
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• pp.51-66
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• 2004

Retinoids, better known as vitamin A, have been reported to inhibit the growth of several breast cancer cell lines in culture and to reduce breast tumor growth in animal models. Furthermore, retinoids can augment the action of other breast cancer cell growth inhibitors both in vitro and in vivo. Clinically, interest has increased in the potential use of retinoids for the prevention and treatment of human breast cancer. We have examine the effect of all-trans retinoic acid(tRA) and 9-cis retinoic acid(9-cis RA) on human breast cancer cell(MCF-10A, T47-D, MCF-7) proliferation using MTT assay and cell cycle analysis(FACS). Overexpression of cyclin D1 protein is observed in the majority of breast cancers, suggesting that dysregulated expression of cyclin D1 might be a critical event in breast cancer carcinogenesis. We investigated whether tRA and 9-cis RA might affect expression of cyclin D1 on human breast cancer cells(MCF-10A, T47-D, MCF-7) using RT-PCR and west-ern bolt. In MCF-10A cells, either tRA or 9-cis RA treatment did not affect the cell proliferation. In T47-D cells and MCF-7 cells, either tRA or 9-cis RA treatment showed the inhibition of the cell proliferation over control cells and also inhibit the estrogen stimulated cell proliferation when it was given together with estrogen. The effect of retinoids was dose- and time- dependent. T47-D cells treated with 1.0 $\muM$ tRA undergo G0/G1-phase arrest by Day 5. MCF-7 cells treated with 1.0 $\muM$ tRA undergo S-phase arrest by Day 5. All-trans retinoic acid(tRA) and 9-cis retinoic acid(9-cis RA) inhibited the cyelin D1 mRNA and protein expression levels of human MCF-7 and T47-D breast carcinoma cells in vitro. The data indicate that retinoids can reduce cyclin D1 expression levels in a variety of breast cell lines in vitro and result in inhibition of cell proliferation. tRA-mediated growth inhibition and cyclin D1 expression inhibition is more potent than 9-cis RA mediated that. tRA-mediated inhibition effect is more potent on T47-D cells than on MCF-7 cells. Our data suggest that retinoids activity is different according to property of cell lines. Future chemoprevention of breast cancer studies using retinoids will be necessary to determine the mechanism of the retinoids-mediated growth inhibition.

• Polymer(Korea)
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• v.34 no.3
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• pp.191-197
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• 2010

To improve the curing method of anisotropic conductive film (ACF) at low temperature, it was studied to replace the thermal latent curing agent of imidazole compounds by the curing agent of cationically initiating type. Thermo-mechanical properties such as glass transition temperature, storage modulus, and coefficient of thermal expansion were investigated for the analysis of curing behavior. The reliability of ACF were observed in thermal cycle and high temperature-high humidity test. ACF using cationic initiator showed faster curing, lower CTE, and higher $T_g$ than the case of using imidazole curing agent, which is important for the high temperature stability. Furthermore, ACF using cationic initiator maintained a stable contact resistance in reliability test, although it was cured at low temperature and fast rate. With these results, it was confirmed that the curing method of epoxy had great effect on thermo-mechanical properties and reliability of ACF.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.171-179
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• 2018

In order to ensure the interoperability of products and technologies, companies apply standard technology in R&D but encounter various obstacles in this process, which they try to overcome through active standardization activities. Various studies have investigated the obstacles and coping strategies of companies in the R&D process. However, studies on the obstacles and coping strategies in the standardization process are insufficient, and the types of obstacles related to standardization, so a variety of studies are also needed on the types of activities. In this study, we tried to determine the types of obstacles related to standardization and to examine how these obstacles affect the standardization activities of companies. The analysis used the data from the 'National Standards Survey' which was conducted by the Korean Standards Association in Korea for companies engaged in the electrical, electronic, and information-related fields in Korea. The relationship between standard-related difficulties, needs and standardization activities was verified through structural equation modeling. The analysis results revealed that the standards-related disability issues have some influence on the standardization activities and the mediating effect by the necessity of the standard was investigated. We also found that many companies are making various efforts to overcome the barriers caused by standard activities. This suggests that a company can build a virtuous cycle structure by performing strategic actions to overcome obstacles by standardization activity and reducing the obstacles caused by standard-related research and development.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.2
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• pp.125-133
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• 2017

KAERI is conducting research on spent cladding hulls and additive metals to generate a solidification host matrix for the noble metal fission product waste in anode sludge from the electro-refining process to minimize the volume of waste that needs to be disposed of. In this study, alloy compositions Zr-17Cr, Zr-22Cr, and Zr-27Cr were prepared with or without eight noble metals representing fuel waste using induction melting. The microstructures of the resulting alloys were characterized and electrochemical corrosion tests were conducted to evaluate their corrosion characteristics. All the compositions had better corrosion characteristics than other Zr-based alloys that were evaluated for comparison. Analysis of the leach solution after the corrosion test of the Zr-22Cr-8NM specimen indicated that the noble metals were not leached during corrosion under 500 mV imposed voltage, which simulates a highly oxidizing disposal environment. The results of this study confirm that Zr-Cr based compositions will likely serve as chemically stable waste forms.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.4
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• pp.259-269
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• 2013

Applicability of ammonium molybdophosphate/iron oxides-polyacrylonitrile (AMP/IO-PAN) composites on the removal of radionuclides in the radioactive wastewater generated from nuclear power plants was investigated. The composites were characterized using the following analytical techniques: X-ray diffraction (XRD), Fourior transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), particle size analyzer (PSA), nitrogen adsorption-desorption and magnetic property measurement system (MPMS). 10wt% of AMP/IO-PAN composite has a saturation magnetization of 2.038 emu/g. Single-solute sorptions of Co, Sr and Cs onto 10wt% of AMP/IO-PAN composite were investigated. The maximum sorption capacities ($Q^0$) predicted by the Langmuir model on 10wt% of AMP/IO-PAN composite were 0.097, 0.086 and 0.66 mmol/g for Co, Sr and Cs, respectively. The maximum sorption capacities ($Q^0$) of Cs predicted by Langmuir model on 0, 10, 20 and 30wt% of AMP/IO-PAN composites were 0.702, 0.655, 0.602 and 0.559 mmol/g, respectively. The maximum sorption capacities ($Q^0$) of Cs decreased with increasing the iron oxide content in the AMP/IO-PAN composites.