• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.80-85
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• 2016

Carbon fiber-reinforced composite materials have been widely used in various industrial fields, but there are limits to increasing their strength and stiffness, because of the short-length fibers that are impregnated in them. In this study, a lab-scale small extruder system was developed with the capability to perform the carbon fiber impregnation and extrusion process in order to evaluate the properties of long-length carbon fiber reinforced thermoplastic composite materials molded by the LFT-D method. Specimens were made with the small extruder to press-mold long-length carbon fiber composite materials and evaluate their material properties. As a result, it was found that the carbon fiber length, press load and carbon fiber contents have a considerable influence on the strength and stiffness. Additional studies on such factors as the mixing screw design and coating of the carbon fiber are needed in order to improve the mechanical properties of carbon fiber composite materials.

• Applied Chemistry for Engineering
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• v.34 no.2
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• pp.106-110
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• 2023

Lignin is compatible with various polymeric materials and useful as a carbon precursor. In this work, carbon monolith films were produced from polyacrylonitrile (PAN)@lignin precursor films by a controlled carbonization cycle. In addition, their morphological features, electrical properties, and adsorption behavior were analyzed and compared with those of carbonized PAN films. The successful formation of PAN@lignin precursor was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. SEM was used to examine the morphology of precursor and carbonized films, revealing that both precursor and carbonized films retained structural stability following carbonization. A trace of lignin in the carbonized films was also found. The pore structure of the carbonized PAN@lignin film was measured using the BET method, indicating the formation of fairly uniform pores. The electrical properties were also analyzed to obtain the Ohmic relation, which demonstrated that the electrical signal was influenced by incoming materials. Finally, the carbonized PAN@lignin films were useful as adsorbents to remove metal ions. This study provides important information for future initiatives in relevant research fields.

• Environmental and Resource Economics Review
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• v.12 no.2
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• pp.245-274
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• 2003

This paper analyzes the economic and environmental impacts of domestic policy to reduce greenhouse gas emissions by focusing on carbon tax, domestic emissions trading and the mixture of these policies. By utilizing a dynamic CGE model, KORTEM, this study shows that the economic cost under carbon tax is projected to be higher than that under emission trading. It is because under carbon tax scheme each emitter in economy must meet its emission target regardless of the abatement cost. On the other hand, emission trading allows emitters to reduce the marginal cost of abatement through trading of emission permits. In designing policy portfolio to address the climate change problem in Korea, therefore, this paper proposes the introduction of domestic emission trading scheme as the main domestic policy Instrument.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1243-1252
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• 2000

The differential enhanced degradation of cis- and trans-1,3-D was observed in the previous two studies performed by several researchers. This study was initiated to investigate the involvement of microorganisms in the differential enhanced degradation of the chemicals. As expected, microorganisms were responsible for the enhanced degradation. A mixed bacterial culture capable of degrading 1,3-D was isolated from an enhanced soil sample collected from a site treated with 1,3-D. Similar to the enhanced soil, the mixed culture degraded trans-1,3-D faster than cis-1,3-D. This mixed culture could not utilize cis- and trans-1,3-D as a sole source of carbon for growth. Rather, a variety of second substrates were evaluated to stimulate the differential enhanced degradation of the two isomers. As a result, the mixed culture degraded cis- and trans-1,3-D only in the presence of a suitable second substrate. Therefore, it appeared that the degradation of cis- and trans-1,3-D was a cometabolic process. Second substrates that had the capacity to stimulate the degradation included soil leachate, tryptone, tryptophan, and alanine. Other substrates tested. including soil extract. glucose, yeast extract and indole, failed to stimulate the degradation of the two isomers. The mixed culture was composed of four morphologically distinctive colonies on L-agar plates.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.05a
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• pp.77-81
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• 2002

콘크리트에 탄소를 혼합하여 제작하면 탄소자체의 흡수성질이 있어 배합콘크리트에 밀실하게 배합되기가 쉽지 않으나 일단 밀실하게 제작되면 압축강도가 크게 개선되는 것으로 전기$\cdot$전도에 큰 성능개선을 할 수 있는 것으로 보여진다. 콘크리트에 전선을 매입하여 그 특성을 개선하는 등 해외 및 국내 연구들이 진행되고 있다. 본 연구에서는 기구 매입 없이 초기 배합에서 곧바로 전기적 특성을 이러한 방향으로 개선하는 방법을 찾는 기초연구를 하는데 있다.(중략)

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1065-1069
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• 1998

This study was investigated to improve peformance of carbon negative electrode for lithium ion secondary battery. The carbon electrode was prepared by mixing with graphitic carbon material, natural graphite, and nongraphitic carbon material, petroleum cokes, which was heat-treated at $700^{\circ}C$ for l hour. Its electrochemical and charge-discharge characteristics were tested according to mixing ratio of different two types of carbon material. The carbon electrode prepared with various mixing ratio showed both charateristcs of two different types of carbon materials and the best characteristics as carbon electrode was demonstrated at mixing ratio of 1:1.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.244-248
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• 2004

$C_{2}H_{2}/NH_{3}/H_{2}$ 의 혼합기체를 Ni 및 Co 촉매 금속에 열분해하여 탄소 나노튜브를 성장하여 구조적 특성을 SEM, TEM 및 Ramann으로 분석을 하였는 바, 성장된 탄소 나노튜브의 직경은 40~100nm 이었으며 모양은 구불구불하며 무질서하게 배열되었다. 탄소 나노튜브로부터의 전계 방출 특성은 통상적인 전계 방출기구에 기인됨을 알 수 있었다. 또한 인가 전압의 증가에 따라 탄소 나노튜브로 부터의 방출된 전류밀도와 휘도는 증가하였으며, $2.5 V/\mu\textrm{m}$의 전계에서는 $3.6 mA/\textrm{cm}^2$의 전류밀도 값을 갖고 있었으며, $0.8\textrm{cm}^2$의 면적에 성장된 탄소 나노튜브로부터 $56 cd/\textrm{m}^2$의 발광 강도를 보였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.3
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• pp.86-91
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• 2024

In this study, the characteristics of mortar using carbondioxide conversion capture materials (CCMs), fabricated by reacting CO₂ with desulfurization gypsum (DG) by-produced from a oil refinery, as a cement mixture. Based on the chemical component and particle size analysis results, it estimated that desulfurized gypsum reacted with carbon dioxide to produce carbonate crystals such as CaCO₃. Using CCMs as a cement mixture, physical property and durability analysis were conducted by measuring such as workability, compressive strength, compressive strength ratio after freezing-thawing and accelerated carbonation depth. The experimental results showed that as the content of the admixture increased, workability and compressive strength characteristics decreased. Compressive strength after freezing-thawing and accelerated carbonation depth also showed similar characteristics to the physical property measurement results. In addition, compared to desulfurized gypsum, using CCMs showed better physical properties and durability. This was assumed to be due to differences in the crystal phases of the mixed materials such as free-CaO and CaCO₃.

• Resources Recycling
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• v.33 no.3
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• pp.12-20
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• 2024

The global cement industry emits approximately 2.9 billion tons of greenhouse gases, of which 1.74-1.89 billion tons are emitted from limestone, which is the main raw material for clinkers. Therefore, the feasibility of using slag, a non-carbonated CaO-based raw material, must be investigated, and the physical properties of cement must be considered. In this study, the mixing ratios of the raw mix and properties of cement were analyzed. The CaCO₃ replacement ratio was limited when one type of slag was used; however, when the mixed slag was utilized, the CaCO₃ replacement ratio increased by more than 12 %. The compressive strength of the slag-incorporated cement was lower than that of Ordinary Portland Cement (OPC). Therefore, the lime saturation factor (LSF) of the raw mix and fineness of the cement were increased to improve the compressive strength. The compressive strength of cement with improved fineness was similar to that of OPC for a CaCO₃ replacement ratio of up to 6 %, and it decreased as the CaCO₃ replacement ratio was increased to 9 %. When both fineness and LSF were increased, the compressive strength and flow value of the cement with a CaCO₃ replacement ratio of 12 % were similar to that of OPC.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.218-226
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• 2013

Of construction materials, cement and steel are the representative material that carbon dioxide. to reduce carbon emissions in the use of these materials The purpose of this study is low heat type blended cement, which is manufactured using a amount of cement than ordinary low heat blended cement. Low heat blended cement, mixing ratio of 10%, was investigated hydration properties and adiabatic temperature of concrete. The study in order to activate the reaction mineral admixture, a separate source of CaO and $SO_3$ areneeded. gypsum and lime, it expected amount of cement, low-carbon low-heat blended cement could reduce the hydration heat concrete than currentlyused low heat blended cement.