• Title/Summary/Keyword: 카본함량

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Effect of Electrode Design on Electrochemical Performance of Highly Loaded LiCoO2 Positive Electrode in Lithium-ion Batteries (리튬이온 이차전지용 고로딩 LiCoO2 양극의 전극설계에 따른 전기화학적 성능연구)

  • Kim, Haebeen;Ryu, Ji Heon
    • Journal of the Korean Electrochemical Society
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    • v.23 no.2
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    • pp.47-55
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    • 2020
  • Highly loaded LiCoO2 positive electrodes are prepared to construct high-energy density lithium-ion batteries, their electrochemical performances are evaluated. For the standard electrode, a loading of about 2.2 mAh/㎠ is used, and for a high-loading electrode, an electrode is manufactured with a loading level of about 4.4 mAh/㎠. The content of carbon black as electronic conducting additive, and the porosity of the electrode are configured differently to compare the effects of electron conduction and ionic conduction in the highly loaded LiCoO2 electrode. It is expected that the electrochemical performance is improved as the amount of the carbon black increases, but the specific capacity of the LiCoO2 electrode containing 7.5 weight% carbon black is rather reduced. When the conductive material is excessively provided, an increase of electrode thickness by the low content of the LiCoO2 active material in the same loading level of the electrode is predicted as a cause of polarization growth. When the electrode porosity increases, the path of ionic transport can be extended, but the electron conduction within the electrode is disadvantageous because the contact between the active material and the carbon black particles decreases. As the electrode porosity is lowered through the sufficient calendaring of the electrode, the electrochemical performance is improved because of the better contact between particles in the electrode and the reduced electrode thickness. In the electrode design for the high-loading, it is very important to construct the path of electron conduction as well as the ion transfer and to reduce the electrode thickness.

The Origin and Characteristics of Sedimentary Organic Matter on Sindu-ri Tidal Flat, Korea (신두리 갯벌 퇴적 유기물의 기원과 특성)

  • Shin, Woo Seok
    • Journal of Wetlands Research
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    • v.22 no.2
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    • pp.59-65
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    • 2020
  • The purpose of this study is to determine the origin of organic matter on sediment at Sindu-ri tidal flat. Grain size, organic matter, C/N ratio and the 13C and δ15N ratio were measured at three stations (Stn. A, B, C) of the tidal flat. As a result, the spatial variation in sediment properties showed that organic matter was related positively to the sediment mud content. Organic matters originating from marine particulate organic matter (marine POM) and fish farm particulate organic matter (fish farm POM) showed sedimentation of organic matters at Stn. A, sandy tidal flat, though terrestial plant (TP) and benthic microalgae (BMA) did at Stn.C, muddy tidal flat. Meanwhile, Stn. B, the intermediate property of Stn. A and C, was affected by marine POM and BMA. Furthermore, it was revealed that the amount and origin of organic matters in the sediments depended on spatial variation, and the factors were different from the stations. Particularly, at the Stn. C, the sediment showed high concentration of TOC in terrestrial organic matter and smaller size particles (< 63 ㎛). These facts suggest the many small size particles and organic matter will affect the sediment environmental condition in the Stn. C.

Efficiency of Retarding Reflection Crack in Reinforced-and-Modified Asphalt Pavement Overlay (개질재.보강재를 이용한 덧씌우기 아스팔트 포장의 반사균열 지연 효과)

  • Kim, Kwang-Woo;Doh, Young-Soo;Lim, Sung-Bin;Rhee, Suk-Keun;Eum, Joo-Yong
    • International Journal of Highway Engineering
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    • v.1 no.1
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    • pp.85-96
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    • 1999
  • This study was performed to evaluate performance of polymer-modified asphalt mixtures and specially designed reinforcement techniques against reflection cracking of the asphalt pavement overlay. Selected polymers were used for asphalt modification and polyester fiber, a polypropylene film (vinyl) and a grid were used for mixture reinforcement. Using the asphalt mixture with optimum asphalt content, a slab was made and cut into two pieces of specimen. A layer of grid or vinyl was placed at the bottom of specimen to strengthen the pavement layer against crack. A repeated loading was applied to the asphalt mixture specimen which is Placed on a cement concrete with a pseudo-crack. Crack propagation under repeated loading was monitored and effectiveness of the devised crack retarding techniques was evaluated. From the test results. a significant retardation of mode I crack progress was monitored from some of the modified and reinforced asphalt mixtures.

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Effects of temperature on Hardness and Stiffness of NR and SBR Vulcanizates (NR과 SBR 가황물의 경도와 강성도 대한 온도의 영향)

  • Jin, Hyun-Ho;Hong, Chong-Kook;Cho, Dong-Lyun;Kaang, Shin-Young
    • Elastomers and Composites
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    • v.42 no.3
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    • pp.143-150
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    • 2007
  • Hardness of rubbery materials, which is important for dimensional stability and product performance, was investigated upon temperature change in this study. A newly developed IRHD (International Rubber Hardness Degree) tester was used to measure the hardness changes of NR and SBR specimens at various temperatures and the hardness values were compared with the Young's modulus. The harness and Young's modulus of NR and SBR showed an abrupt change near the glass transition temperatures. The hardness and Young's modulus were increased by increasing temperature due to the increased random chain conformation of molecules. The effect of temperature on hardness and Young's modulus of NR and SBR specimens filled with carbon black and silica was decreased by increasing filler content.

Effects of Fillers on Fatigue Crack Growth Rate of Ethylene Propylene Diene Monomer (충전제가 EPDM의 피로균열 성장속도에 미치는 영향)

  • Hong, Chang-Kook;Jung, Jae-Yeon;Cho, Dong-Lyun;Kaang, Shin-Young
    • Polymer(Korea)
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    • v.32 no.3
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    • pp.270-275
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    • 2008
  • Crack growth characteristics of elastomeric materials are an important factor determining the strength and durability. In this study, the fatigue crack growth characteristic of filled EPDM compounds with different reinforcing fillers, such as silica and carbon black, was investigated using a newly designed tester. Frequency and test temperature had significant effects on the fatigue crack growth. The crack growth rate decreased with increasing frequency and the rate increased with increasing temperature. A power law relationship between the tearing energy and crack growth was observed for filled EPDM compounds. The crack growth rate reduced with increasing filler contents. Silica filled EPDM showed a better fatigue resistance than carbon black filled EPDM. The crack growth rate of silica filled EPDM decreased up to 30 phr and increased again at 50 phr. The formation of microductile type pits was observed on the fatigue-failure surface of unfilled EPDM, and relatively coarse surface with randomly distributed tear lines was observed on the failure surface of silica filled EPDM.

Effect of Carbon Materials on the Slag Foaming in EAF Process (전기로 슬래그 포밍에 미치는 가탄재 종류의 영향)

  • Kim, Young-Hwan;Yoo, Jung-Min;Um, Hyung-Sic
    • Resources Recycling
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    • v.28 no.2
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    • pp.40-45
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    • 2019
  • During steelmaking in EAF, recycled scraps is used as a main material, melted by arc, and electricity use as a main energy. Slag foaming is an important technology for reducing electrical energy. CO gas generated by the reaction between injection carbon and (FeO), [C] and injection {$O_2$}. CO gas generated by this reaction is collected in slag, resulted in slag foaming. In general, the carbon materials used in the EAF process is anthracite and coke. This study investigated the effects of the carbon materials used on slag foaming in the steelmaking process. As a result of this study, the slag foaming height is increased by cokes rather than anthracite, and with an increase in the amount of particles samller than $500{\mu}m$. Based on these results, the application to the operation resulted in increase of slag forming height, reduction of injection carbon, and reduction of electrical energy.

Preparation and Characterization of Pitch-based Carbon Paper for Low Energy and High Efficiency Surface Heating Elements (저전력 및 고효율 면상발열체를 위한 피치기반 탄소종이 제조 및 특성)

  • Yang, Jae-Yeon;Yoon, Dong-Ho;Kim, Byoung-Suhk;Seo, Min-Kang
    • Composites Research
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    • v.31 no.6
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    • pp.412-420
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    • 2018
  • In this work, phenolic resins containing conductive carbon fillers, such as, petroleum coke, carbon black, and graphite, were used to improve the surface heating elements by impregnating a pitch-based carbon paper. The influence of conductive carbon fillers on physicochemical properties of the carbon paper was investigated through electrical resistance measurement and thermal analysis. As a result, the surface resistance and interfacial contact resistivity of the carbon paper were decreased linearly by impregnating the carbon fillers with phenol resins. The increase of carbon filler contents led to the improvement of electrical and thermal conductivity of the carbon paper. Also, the heating characteristics of the surface heating element were examined through the applied voltage of 1~5 V. With the applied voltage, it was confirmed that the surface heating element exhibited a maximum heating characteristic of about $125.01^{\circ}C$(5 V). These results were attributed to the formation of electrical networks by filled micropore between the carbon fibers, which led to the improvement of electrical and thermal properties of the carbon paper.

Effect of Carbon Filler and Ester Type Binder on the Reactivity and Adhesive Properties with PET Film of Conductive Paste (탄소필러와 에스테르계 바인더가 전도성 페이스트의 반응성 및 PET 필름과의 접착특성에 미치는 영향)

  • Shim, Chang Up;Ku, Hyo Sun;Kim, Youn Cheol
    • Applied Chemistry for Engineering
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    • v.33 no.4
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    • pp.381-385
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    • 2022
  • It is very important to secure the adhesion durability between the base film and the conductive paste for the development of a sensor for detecting hazardous chemicals. In this study, an ester binder was used to improve the adhesive properties which can be a problem when applying the sensor to the cross cut 0B or 1B grade. This problem was found while evaluating the adhesive properties by coating the polyaniline/graphene nano plate (GNP) paste on the polyethylene terephthalate (PET) film. When 10 wt% or more of the ester-based binder was added, the cross cut grade to which the sensor can be applied was 3B or higher. It was confirmed that the excessive addition of the binder may affect the electrical properties of the conductive paste and actually decrease the reactivity to sulfuric acid. To improve the electrical property, a carbon black (CB) content was varied resulting in the optimum electrical property observed at 2 wt% of CB.

An Oxyfluorination Effect of Carbon Nanotubes Supports on Electrochemical Behaviors of Platinum Nanoparticle Electrodes (백금 나노입자전극의 전기화학적 거동에 대한 카본나노튜브 지지체의 산소-불소 처리효과)

  • Kim, Seok;Lee, Jae-Rock;Park, Soo-Jin
    • Korean Chemical Engineering Research
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    • v.46 no.1
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    • pp.118-123
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    • 2008
  • In the present study, the effect of oxyfluorination treatment on multi-walled nanotubes (MWNTs) supports was investigated by analyzing surface functional groups. The surface characteristics were determined by Fourier transformed-infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). After the deposition of platinum nanoparticles on the above treated carbon supports, a crystalline size and a loading level had been investigated. Electrochemical properties of the treated MWNTs-supported Pt (Pt/MWNTs) catalysts were analyzed by current-voltage curve measurements. From the results of surface analysis, an oxygen and fluorine-containing functional group had been introduced to the surface of carbon supports. The oxygen and fluorine contents were the highest value at the treatment of 100 temperature. The Pt/100-MWNTs showed the smallest particle crystalline size of 3.5 nm and the highest loading level of 9.4% at the treatment of 100 temperature. However, the sample treated at the higher temperature showed the larger crystalline size and the lower loading level. This indicated that the crystalline size and the loading level could be controlled by changing the temperature of oxyfluorination treatment. Accordingly, an electrochemical activity was enhanced by increasing the temperature of treatment upto 100, and then decreased in the case of 200 and 300. The highest specific current density of 120 mA/mg had been obtained in the case of Pt/100-MWNTs.

Natural Rubber-Clay Nanocomposites by Latex Method : Morphology and Mechanical Properties (라텍스법에 의한 천연고무-클레이 나노 복합재료: 모폴로지와 기계적 물성)

  • Kim, W.H.;Kang, J.H.;Kang, B.S.;Cho, U.R.
    • Elastomers and Composites
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    • v.41 no.1
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    • pp.27-39
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    • 2006
  • In this study, modified DA-MMT filled NR/DA-MMT nanocomposites were manufactured by a latex method and a compounding method. Cure characteristics and mechanical properties of the Cloisite 15A, carbon black, Na-MMT filled NR compounds and the DA-MMT filled NR compound by a latex method were also evaluated. The filler content of all compounds was 10phr except the carbon black filled compound. Degree of intercalation and dispersion was characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). According to the XRD diffraction pattern and TEM analysis, extensive intercalation and homogeneous dispersion of the clay were obtained after the two-roll milling. Although the layer distance was increased, some parts of DA-MMT showed the layer distance of Na-MMT after vulcanization. DA-MMT filled NR compounds showed the highest ODR torques, tensile strength, modulus, and tear energy. The NR/DA-MMT nanocomposite (by a latex method) compared with a NR/DA-MMT nanocomposite (by a compounding method) was found that the improvement of the mechanical properties was mainly due to the degree of dispersion of the clay.