• Title/Summary/Keyword: nano material

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Recent Trend in Measurement Techniques of Emotion Science (감성과학을 위한 측정기법의 최근 연구 동향)

  • Jung, Hyo-Il;Park, Tae-Sun;Lee, Bae-Hwan;Yun, Sung-Hyun;Lee, Woo-Young;Kim, Wang-Bae
    • Science of Emotion and Sensibility
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    • v.13 no.1
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    • pp.235-242
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    • 2010
  • Emotion science is one of the rapidly expanding engineering/scientific disciplines which has a major impact on human society. Such growing interests in emotion science and engineering owe the recent trend that various academic fields are being merged. In this paper we review the recent techniques in the measuring the emotion related elements and applications which include animal model system to investigate the neural network and behaviour, artificial nose/neuronal chip for in-depth understanding of sensing the outer stimuli, metabolic controlling using emotional stimulant such as sounds. In particular, microfabrication techniques made it possible to construct nano/micron scale sensing parts/chips to accommodate the olfactory cells and neuron cells and gave us a new opportunities to investigate the emotion precisely. Recent developments in the measurement techniques will be able to help combine the social sciences and natural sciences, and consequently expand the scope of studies.

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Blood Protein Adsorption and Platelet Activation on an Ultra-hydrophilic Substrate (초친수성 표면에서 혈장 단백의 흡착 및 혈소판의 변화에 관한 연구)

  • Park, Nam-Hee;Chun, Bae-Hyeock;Je, Hyung-Gon;Lee, Jun-Wan;Lee, Jae-Won
    • Journal of Chest Surgery
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    • v.40 no.4 s.273
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    • pp.273-279
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    • 2007
  • Background: We evaluate the efficacy of ultra-hydrophilic coated bypass circuits in comparison with uncoated bypass circuits in a porcine cardiopulmonary bypass model. Material and Method: Normothermic cardiopulmonary bypass was peformed in 10 anesthetized pigs via the left atrium and ascending aorta with a centrifugal biopump. Ultra-hydrophilic coated bypass circuits wore used in 5 pigs (the study group) and uncoated bypass circuits were used for the control group. Platelet counts and platelet aggregation tests were peformed. The thrombin-antithrombin(TAT) complex level and total protein level were evaluated. Result: There were no significant changes En the platelet counts and aggregation ability of both groups. The TAT complex levels were not different between the two groups. The total protein level was significantly lower in the control group after cessation of cardiopulmonary bypass. Conclusion: The clinical effects of ultra-hydrophilic coating circuits were not remarkable, in terms of reducing inflammatory reaction and protection of platelet function. However, the effect of protection for blood protein adsorption might be acceptable.

Preparation of Transparent Film by Coating of Acrylate Copolymer as MMA-co-GMA-co-AA ((MMA-co-GMA-co-AA)형 아크릴레이트 공중합체를 도포한 투명필름의 제조)

  • Kim, Ji-Hye;Kim, Moon-Sun;Hong, Sung-Chul;Kim, Byung-Woo
    • Korean Chemical Engineering Research
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    • v.49 no.1
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    • pp.62-68
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    • 2011
  • In the study, acrylate copolymer as MMA-co-GMA-co-AA with a high hardness and flexibility was synthesized for applying to the clear protection film, where GMA was used as a mediator to enhance polymerization-efficiency between MMA and AA. With an increase of GMA content, molecular weight and hardness of acrylate copolymer increased, however, flexibility decreased. With an increase of AA content, its molecular weight and hardness decreased, however, flexibility increased. Molar ratio of GMA/MMA and AA/GMA were optimized as 1.6 and 1.8, respectively, at 30 g of MMA to enhance hardness and flexibility of acrylate copolymer film. Molecular weight and Tg of the acrylate copoylmer were 13,300 g/mol and 136.5 $^{\circ}C$, respectively. Hardness of the coated film at 1.4 g/$m^2$ of spread was 1 H and no crack was observed at expansion ratio of 5% and 15%, respectively. Hardness of film was improved to 3 H by increasing spread of 4.1-4.6 g/$m^2$.

Comparative Study on Material Characteristics of Joseon White Wares Excavated from Gangwon Wonju Province (강원 원주지역 조선백자의 재료학적 특성 비교연구)

  • Lee, Byeong Hoon;So, Myoung-Gi
    • Journal of Conservation Science
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    • v.33 no.4
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    • pp.225-239
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    • 2017
  • This study aimed to investigate the chemical properties and production techniques for white wares from the Gwirae-1ri 3rd, Songok-3ri 2nd kiln sites in Kangwon Wonju regions. Further, another aim was to determine the correlation among the materials used to produce the white wares. The analysis of white wares in Kangwon Wonju regions produced the following results. The excavated white wares were analyzed using the Seger formula, and all the samples showed similar clay sources ($RO_2:4.33-5.82$, $RO+R_2O:0.32-0.43$) and glaze sources. Moreover, the white wares were made of host rocks of the same geological origin, according to the results of the rare earth elements analysis. When the crystalline phases of the white wares were investigated via the XRD analysis, quartz and mullite were found in all the samples, and their proportions were similar to each other. Although the firing temperatures for the samples were different, most were fired at a temperature below $1,200^{\circ}C$, with some being fired at temperatures as low as $1,000{\pm}20^{\circ}C$.

Investigation of Friction and Wear Characteristics of Cast Iron Material Under Various Conditions (다양한 조건에 따른 주철 소재의 마찰/마모 특성에 관한 연구)

  • Joo, Ji-Hoon;Kim, Chang-Lae;Nemati, Narguess;Oh, Jeong-Taek;Kim, Dae-Eun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.8
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    • pp.765-772
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    • 2015
  • Cast iron is widely used in fields such as the transport and heavy industries. For parts where contact damage is expected to occur, it is necessary to understand the friction and wear characteristics of cast iron. In this study, we use cast iron plates as the specimens to investigate their friction and wear characteristics. We perform various experiments using a reciprocating type tribotester. We assess the frictional characteristics by analyzing the friction coefficient values that were obtained during the sliding tests. We observe the wear surfaces of cast iron and steel balls using a scanning electron microscope, confocal microscope, and 3d profiler. We investigate the friction and wear characteristics of cast iron by injecting sand and alumina particles having various sizes. Furthermore, we estimate the effect of temperature on the friction and wear characteristics. The results obtained are expected to aid in the understanding of the tribological characteristics of cast iron in industry.

Study of Magnetic Field Shielded Sputtering Process as a Room Temperature High Quality ITO Thin Film Deposition Process

  • Lee, Jun-Young;Jang, Yun-Sung;Lee, You-Jong;Hong, Mun-Pyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.288-289
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    • 2011
  • Indium Tin Oxide (ITO) is a typical highly Transparent Conductive Oxide (TCO) currently used as a transparent electrode material. Most widely used deposition method is the sputtering process for ITO film deposition because it has a high deposition rate, allows accurate control of the film thickness and easy deposition process and high electrical/optical properties. However, to apply high quality ITO thin film in a flexible microelectronic device using a plastic substrate, conventional DC magnetron sputtering (DMS) processed ITO thin film is not suitable because it needs a high temperature thermal annealing process to obtain high optical transmittance and low resistivity, while the generally plastic substrates has low glass transition temperatures. In the room temperature sputtering process, the electrical property degradation of ITO thin film is caused by negative oxygen ions effect. This high energy negative oxygen ions(about over 100eV) can be critical physical bombardment damages against the formation of the ITO thin film, and this damage does not recover in the room temperature process that does not offer thermal annealing. Hence new ITO deposition process that can provide the high electrical/optical properties of the ITO film at room temperature is needed. To solve these limitations we develop the Magnetic Field Shielded Sputtering (MFSS) system. The MFSS is based on DMS and it has the plasma limiter, which compose the permanent magnet array (Fig.1). During the ITO thin film deposition in the MFSS process, the electrons in the plasma are trapped by the magnetic field at the plasma limiters. The plasma limiter, which has a negative potential in the MFSS process, prevents to the damage by negative oxygen ions bombardment, and increases the heat(-) up effect by the Ar ions in the bulk plasma. Fig. 2. shows the electrical properties of the MFSS ITO thin film and DMS ITO thin film at room temperature. With the increase of the sputtering pressure, the resistivity of DMS ITO increases. On the other hand, the resistivity of the MFSS ITO slightly increases and becomes lower than that of the DMS ITO at all sputtering pressures. The lowest resistivity of the DMS ITO is $1.0{\times}10-3{\Omega}{\cdot}cm$ and that of the MFSS ITO is $4.5{\times}10-4{\Omega}{\cdot}cm$. This resistivity difference is caused by the carrier mobility. The carrier mobility of the MFSS ITO is 40 $cm^2/V{\cdot}s$, which is significantly higher than that of the DMS ITO (10 $cm^2/V{\cdot}s$). The low resistivity and high carrier mobility of the MFSS ITO are due to the magnetic field shielded effect. In addition, although not shown in this paper, the roughness of the MFSS ITO thin film is lower than that of the DMS ITO thin film, and TEM, XRD and XPS analysis of the MFSS ITO show the nano-crystalline structure. As a result, the MFSS process can effectively prevent to the high energy negative oxygen ions bombardment and supply activation energies by accelerating Ar ions in the plasma; therefore, high quality ITO can be deposited at room temperature.

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Synthesis of Porous Cu-ZnO Composite Sphere and CO Oxidation Property (기공성 Cu-ZnO 복합 구형 산화물의 합성 및 CO 산화반응 특성)

  • Park, Jung-Nam;Hwang, Seong-Hee;Jin, Mingshi;Shon, Jeong-Kuk;Kwon, Sun-Sang;Boo, Jin-Hyo;Kim, Ji-Man
    • Applied Chemistry for Engineering
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    • v.21 no.3
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    • pp.328-332
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    • 2010
  • In this study, porous ZnO sphere and Cu-ZnO composite were synthesized by coprecipitation method in diethylene glycol solvent. The physicochemical properties of as-prepared composite materials were characterized by SEM, XRD, $N_2$-sorption and $H_2$-TPR. A series of porous Cu-ZnO with different Cu contents (0, 6.6, 21.3, 36.4, 54.6, 77.8 wt%) was investigated for CO oxidation activity in a fixed bed reactor system. With increasing Cu content in Cu-ZnO the surface area and micropore volume of Cu-ZnO are decreased and Cu (36.4 wt%)-ZnO shows higher activity for CO oxidation compared to the others.

Flexibility Study of Silicon Thin Film Transferred on Flexible Substrate (폴리머 기판 위에 전사된 실리콘 박막의 기계적 유연성 연구)

  • Lee, Mi-Kyoung;Lee, Eun-Kyung;Yang, Min;Chon, Min-Woo;Lee, Hyouk;Lim, Jae Sung;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
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    • v.20 no.3
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    • pp.23-29
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    • 2013
  • Development of flexible electronic devices has primarily focused on printing technology using organic materials. However, organic-based flexible electronics have several disadvantages, including low electrical performance and long-term reliability. Therefore, we fabricated nano- and micro-thick silicon film attached to the polymer substrate using transfer printing technology to investigate the feasibility of silicon-based flexible electronic devices with high performance and high flexibility. Flexibility of the fabricated samples was investigated using bending and stretching tests. The failure bending radius of the 200 nm-thick silicon film attached on a PI substrate was 4.5 mm, and the failure stretching strain was 1.8%. The failure bending radius of the micro-thick silicon film attached on a FPCB was 2 mm, and the failure strain was 3.5%, which showed superior flexibility compared with conventional silicon material. Improved flexibility was attributed to a buffering effect of the adhesive between the silicon film and the substrate. The superior flexibility of the thin silicon film demonstrates the possibility for flexible electronic devices with high performance.

Characterization and synthesis of aqueous pink-red ceramic ink for digital inkjet printing (잉크젯 프린팅용 pink-red 수계 무기잉크의 제조 및 특성평가)

  • Lee, Won-Jun;Hwang, Hae-Jin;Han, Kyu-Sung;Cho, Woo-Suk;Kim, Jin-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.25 no.1
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    • pp.20-26
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    • 2015
  • Ceramic ink-jet printing technology in art tiles, decorated tablewares and other porcelain products has many advantages of fast and precision printing of various images with high efficiency and low cost. For the application to ink-jet printing, ceramic ink requires a stable dispersibility with nano-sized pigments. In this paper, characteristics of pink-red aqueous ceramic ink for ink-jet printing was demonstrated. $CaCr_{0.1}Sn_{0.8}SiO_5$ pigment was synthesized using solid state reaction and deagglomerated using attrition milling. The aqueous ceramic ink contains 10 wt% of the obtained $CaCr_{0.1}Sn_{0.8}SiO_5$ nanopigment with 0.4 wt% of sodium dodecyl sulfate (SDS) as a dispersion agent. Viscosity of $CaCr_{0.1}Sn_{0.8}SiO_5$ aqueous ceramic ink was adjusted using 0.18 wt% of polyvinyl alcohol (PVA) for a suitable jetting from the nozzle. The prepared pink-red ceramic ink showed a good jetting property with formation of a single sphere-shaped droplet after $180{\mu}s$ without a tail and satellite droplet.

Preparation of LiFe PO4 Using Chitosan and its Cathodic Properties for Rechargeable Li-ion Batteries

  • Hong, Kyong-Soo;Yu, Seong-Mi;Ha, Myoung-Gyu;Ahn, Chang-Won;Hong, Tae-Eun;Jin, Jong-Sung;Kim, Hyun-Gyu;Jeong, Euh-Duck;Kim, Yang-Soo;Kim, Hae-Jin;Doh, Chil-Hoon;Yang, Ho-Soon;Jung, Hee
    • Bulletin of the Korean Chemical Society
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    • v.30 no.8
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    • pp.1719-1723
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    • 2009
  • The LiFeP$O_4$ powder was synthesized by using the solid state reaction method with Fe($C_2O_4){\cdot}2H_2O,\;(NH_4)_2HPO_4,\;Li_2CO_3$, and chitosan as a carbon precursor material for a cathode of a lithium-ion battery. The chitosan added LiFePO4 powder was calcined at 350 ${^{\circ}C}$ for 5 hours and then 800 ${^{\circ}C}$ for 12 hours for the calcination. Then we calcined again at 800 ${^{\circ}C}$ for 12 hours. We characterized the synthesized compounds via the crystallinity, the valence states of iron ions, and their shapes using TGA, XRD, SEM, TEM, and XPS. We found that the synthesized powders were carbon-coated using TEM images and the iron ion is substituted from 3+ to 2+ through XPS measurements. We observed voltage characteristics and initial charge-discharge characteristics according to the C rate in LiFeP$O_4$ batteries. The obtained initial specific capacity of the chitosan added LiFeP$O_4$ powder is 110 mAh/g, which is much larger than that of LiFeP$O_4$ only powder.