• 한국수소및신에너지학회논문집
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• 제16권2호
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• pp.159-169
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• 2005

Cellulose, consisted of 45 wt% in wood, is usable as fuels and heavy oil additives if depolymerized to monomer unit, because the chemical structures are similar to high octane materials found in gasoline. In this study, thermochemical degradation by solvolysis reaction of cellulose such as the effect of reaction temperature, reaction time and type of solvent on conversion yield and degradation products were investigated. It was found that the effectiveness of the solvent on the sovolysis reaction was as follows; acetone>n-butanol>tetralin. When acetone was used as a solvent, the highest cellulose conversion was observed to be 91.8% at 500$^{\circ}C$, 40min. Combustion heating value of liquid products from thermochemical conversion processes was in the range of 7,330${\sim}$7,410cal/g. The energy yield and mass yield in acetone-solvolysis of cellulose was as high as 66.8% and 37.0 g oil/100g raw material after 40min of reaction at 400$^{\circ}C$. Various aliphatic and aromatic compounds were detected in the cellulose solvolysis products. The major components of the solvolysis products, that could be used as fuel, were mesityl oxide, mesitylene, isophorone.

• 한국분말재료학회지
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• 제24권2호
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• pp.147-152
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• 2017

Spherical-type zirconia granules are successfully fabricated by a spray-drying process using a water solvent slurry, and the change in the green density of the granule powder compacts is examined according to the organic polymers used. Two organic binders, polyvinyl alcohol (PVA) and 2-hydroxyethyl methacrylate (HEMA), which are dissolved in a water solvent and have different degrees of polymerization, are applied to the slurry with a plasticizer (polyethylene glycol). The granules employing a binder with a higher degree of polymerization (PVA) are not broken under a uniaxial press; consequently, they exhibit a poor green density of $2.4g/cm^3$. In contrast, the granule powder compacts employing a binder with a lower degree of polymerization (HEMA) show a higher density of $2.6g/cm^3$ with an increase in plasticizer content. The packing behavior of the granule powders for each organic polymer system is studied by examining the microstructure of the fracture surface at different applied pressures.

• Journal of Electrochemical Science and Technology
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• 제14권3호
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• pp.262-271
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• 2023

For electrode stability and the electrochemical performance of the Li-ion cell, it is essential that the active ingredients and unique additives in the polymer binder be well dispersed with the solvent-based slurry. The efficient procedure used to create the slurry affects the rheological characteristics of the electrode slurry. When successively adding different steps of Nmethyl-2-pyrrolidone (NMP) solvent to the cathode composition, it is evenly disseminated. The electrochemical performance of the Li-ion cells and the electrodes made with slurry formed by single step and multiple steps of addition of NMP solvent are examined. To preform rheological properties of cathode electrode slurry on Ni-rich Lithium Nickel-Cobalt-Aluminum Oxide (LiNi_0.80Co_0.15Al_0.05) (NCA). Also, we investigate different step addition of electrode formation and mechanical strength characterization like peel strength. According to the EIS study, a multi-step electrode slurry has lower internal resistance than a single-step electrode slurry, which results in better electrical characteristics and efficiency. Further, microstructure of electrodes is obtained electrochemical performance in the 18650 cylindrical cells with targeted capacity of 1.5 Ah. The slurry of electrodes prepared by single step and multiple steps of addition of NMP solvent and its effect on the fabrication of 1.5 Ah cells. A three-step solvent addition on slurry has been found to be a lower internal resistance than a single-step electrode slurry as confirmed by the EIS analysis, yielding improved electrical properties and efficiency.

• 한국응용과학기술학회지
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• 제31권3호
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• pp.486-491
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• 2014

본 연구에서는, 유기용매를 사용하지 않는 친 환경적인 건식 공정과 초임계 공정을 이용한 Thin-multiwalled carbon nanotube (TWNTs)/아민계 에폭시 첨가제의 복합체 제조에 관하여 연구를 하였다. 제조된 TWNTs/아민계 에폭시 첨가제의 복합체는 우레탄기반의 비스페놀 A 타입의 에폭시 레진의 경화제로 사용하였다. TWNTs/아민계 에폭시 첨가제의 복합체를 경화제로 사용하여 제조된 에폭시 레진의 열적 성질을 Dynamic mechanical analysis (DMA)를 이용하여 분석 하였으며, 메트릭스상의 carbon nanotube의 높은 분산성은 SEM을 통하여 확인 하였다. 그 결과, 초임계 공정을 이용하여 제조된 에폭시 레진의 열적 성질과 매트릭스내의 carbon nanotube 분산성이 건식 공정을 사용 하였을 때 보다 더욱 증가된 결과를 확인 할 수 있었다.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.130-135
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• 2010

Paint is used as top coat in Automobile Refinishing that is divided into 1K paint of base type and 2K paint of urethane type. after using 1K paint, it can be reusable. However 2K paint is not available that is mixed a certain amount of base with hardner, so 2K paint has to be used all at a time or discarded the rest. This study covered that colored Urethane paint and colorless urethane paint in top coating process of AR. Top coat urethane paint is divided into colored urethane paint and transparent urethane paint like clear coat. Colored urethane paint is used for paint that contains resin, pigment, solvent and additives. It is color such as black and white. While transparent urethane paint is used for paint that contains resin, solvent and additives. Urethane paint has a paint system that cur after several hours of mixing base and hardner. By a paint technician of a field and empirical data, we can also recognize that according to worker's paint style and experience, although he or she paint same car model and area, paint use of one's is different. There aren't guidelines workers refer to about paint use by car models and work scope because ARP works various car models that are in different color, size and area. After using urethane paint, the rest of paint has come, and there are highs and lows in paint use each time he or she works. Therefore, this study suggest a basic guideline to use paint efficiently and regularly by understanding area, the type of work, and paint use that are appropriate for each car model and regardless of workers and work scopes in AR.

• 한국세라믹학회지
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• 제40권3호
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• pp.249-254
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• 2003

AI, AIN 및 질화반응 촉진을 위한 첨가제로서 Li$_2$CO$_3$, Y$_2$O$_3$, CaCO$_3$를 혼합한 후 성형체를 제조하여 질소 분위기에서 열처리하였고, 용매 및 첨가제의 종류와 질화온도가 AI-AIN계의 질화반응에 미치는 영향에 대하여 고찰하였다. 1.0wt%의 olcic acid.를 첨가한 ethanol을 혼합용매로 사용한 경우 AI과 AIN 입자의 표면개질 효과를 질화반응시 산화물 생성을 최소화시킬 수 있었다. 그리고 AI-AIN계에 Li$_2$CO$_3$ 또는 CaCO$_3$를 첨가한 경우Y$_2$O$_3$를 첨가한 경우에 비하여 질화 열처리시 생성되는 산화물의 생성을 크게 억제시킬 수 있었다.

• 한국재료학회지
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• 제22권10호
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• pp.531-538
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• 2012

Hollow silica spheres were prepared by spray drying of precursor solution of colloidal silica. The precursor solution is composed of 10-20 nm colloidal silica dispersed in a water or ethanol-water mixture solvent with additives of tris hydroxymethyl aminomethane. The effect of pH and concentrations of the precursor and additives on the formation of hollow sphere particles was studied. The spray drying process parameters of the precursor feeding rate, inlet temperature, and gas flow rate are controlled to produce the hollow spherical silica. The mixed solvent of ethanol and water was preferred because it improved the hollowness of the spheres better than plain water did. It was possible to obtain hollow silica from high concentration of 14.3 wt% silica precursor with pH 3. The thermal conductivity and total solar reflectivity of the hollow silica sample was measured and compared with those values of other commercial insulating fillers of glass beads and $TiO_2$ for applications of insulating paint, in which the glass beads are representative of the low thermal conductive fillers and the $TiO_2$ is representative of infrared reflective fillers. The thermal conductivity of hollow silica was comparable to that of the glass beads and the total solar reflectivity was higher than that of $TiO_2$.

• 한국도로학회논문집
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• 제17권4호
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• pp.53-61
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• 2015

PURPOSES : The objective of this study is to evaluate the SDAR (solvent deasphaltene residue), which is obtained from the solvent deasphalting (SDA) process, as a pavement material. METHODS : The physical properties of the SDAR were evaluated based on its chemical composition, and asphalt mixtures with the SDAR were fabricated and used for the evaluation of mechanical properties. Firstly, the chemical composition of SARA (saturate, aromatic, resin and asphaltene) was analyzed using the TLC-FID (thin-layer chromatography-flame ionization detector). Moreover, the basic material properties of the asphalt binder with the SDAR were evaluated by the penetration test, softening point test, ductility test, and PG (performance grade) grade test. The rheological properties of the asphalt binder with the SDAR were evaluated by the dynamic shear modulus ($G^*$) obtained using the time-temperature superposition (TTS) principle. Secondly, the mechanical properties of the asphalt mixtures with the SDAR were evaluated. The compactibility was evaluated using the gyratory compacter. Moreover, the tensile strength ratio (TSR) was used for evaluating the moisture susceptibility of the asphalt mixtures (i.e., susceptibility to pothole damage). The dynamic modulus $E^*$, which is a fundamental property of the asphalt mixture, obtained at different temperatures and loading cycles, was used to evaluate the mechanical properties of the asphalt mixtures. RESULTS AND CONCLUSION : The SDAR shows stiffer and more brittle behavior than the conventional asphalt binder. As the application of the SDAR directly in the field may cause early failures, such as cracks on pavements, it should be applied with modifiers that can favorably modify the brittleness property of the SDAR. Therefore, if appropriate additives are applied on the SDAR, it can be used as a pavement material because of its low cost and strong resistance to rutting.

• 한국약용작물학회지
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• 제18권1호
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• pp.28-33
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• 2010

Glycyrrhiza uralensis (Leguminosae) is a well-known herbal medicine that has long been valued as a demulcent to relieve inflammatory disorders. To compare the influence of different solvents on the anti-inflammatory efficacy of G. uralensis, we measured the inhibition of pro-inflammatory mediators such as NO, TNF-$\alpha$, and $PGE_2$ in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells by extracts produced using different solvents (water, methanol, ethanol, or n-hexane). The results showed that methanol was the most effective solvent for the inhibition of both NO and $PGE_2$ production in RAW 264.7 cells. However, there was no difference among the extracts for inhibition of TNF-$\alpha$. Further study must be performed for the analysis of correlation between the anti-inflammatory activity of extracts produced using different solvents and the content of major bioactive compounds in G. uralensis, such as glycyrrhizin and liquiritin. The present study suggests that methanol may be a more appropriate solvent of G. uralensis than other solvents (water, ethanol, and n-hexane) to yield the greatest anti-inflammatory activity for food additives and medicine.

• KSBB Journal
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• 제16권4호
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• pp.327-331
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• 2001

전라남도 보성산 녹차로부터 유용성분인 카테킨 화합물을 초임계 이산화 탄소와 첨가제를 사용하여 추출하고 역상 고성능 액체 크로마토그래피(RP-HPLC)를 사용하여 분석하였다. LiChrospher 100RP-18(15 $\mu$m)로 충진된 column을 이용하여 0.05% phosphoric acid가 포함된 물과 acetonitrile을 이동상으로 사용하였으며 구배용매 조성법을 적용하였다. 이동상의 조성에 따른 체류인자의 조절을 통해 EGCG를 분리하였다. 각각의 초임계 추출법에 따른 EGCG의 추출량을 비교한 결과, 초임계 유체에 극성물질을 포함하는 경우가 녹차의 유용 성분인 EGCG의 추출량이 가장 많았다. 그러나 ethanol에 의한 용매 추출법은 초임계 유체에 의한 추출법보다 EGCG에 대해 많은 추출양과 선택적인 고순도 분리가 가능하였다.