• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2003.04a
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• pp.108-111
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• 2003

현대인의 생활환경 변화에 따라 레져 산업의 급격한 증가로 인해 관련산업에 많은 영향을 주고 있다. 특히 스포츠 분야에서는 의류, 신발 및 장비 분야에서 새로운 제품에 대한 수요가 증가하고 있다. 이들 제품이 요구하는 물성은 각종 기후조건에서 인체를 보호하고 착용자가 쾌적함을 느낄 수 있어야 한다. 이러한 기능을 충족시키기 위해서는 운동 중에 발생하는 땀을 발산하고 외부에서의 수분의 침투를 막아 체온의 급격한 변화가 나타나지 않도록 투습방수성을 나타내어야 한다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.21-24
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• 1998

흡수성 고분자는 주로 기저귀, 생리대, 농업용 뿌리 덮개 등에 사용되며, PAN(폴리아크릴 로니트릴) 그라프트 전분으로 대표되는 그라프트 공중합체와 가교된 아크릴레이트 고분자로 대표되는 수용성 단량체의 단중합체 또는 공중합체 등에 대한 연구가 가장 활발히 이루어져 왔다. 이들 고흡수성 재료들은 염용액에 대한 흡수도가 낮다는 단점이 있으며, 보다 강한 이온기를 도입하거나, 고흡수성 재료가 양쪽성을 나타낼 경우, 염에 대한 흡수도가 개선된다는 연구결과가 보고된바 있다. (중략)

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.326-333
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• 1996

Dehydrogenation of 4-vinylcyclohexene(4-VCH) to ethylbenzene is elucidated via catalytic transfer hydrogenation with the heterogeneous catalyst of Pd/C. Hydrogen-donor solvent is ethanol or water. Oxidizers of the catalytic dehydrogenation reaction are mono- or dinitro compounds, $H_2O_2$, NaClOn (n=1~4), or oxygen at $70{\sim}110^{\circ}C$. The ratio of 4-VCH/Nitro compounds is 1:0.02 to 1:0.5 and 4-VCH vs. $H_2O_2$ or NaClOn (n=1~4) is 1:0.1 to 1:3.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.4
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• pp.300-305
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• 2000

We have investigated the dielectric and electrical characteristics of palmitic acid(PA) stearic acid(SA) and arachidic acid(AA) Langmuir-Blodgett(LB) films because these fatty acid systems have a same hydrophilic group and a different hydrophobic one(methylene group or alkyl chain length). The fatty acid systems were used as LB films and the status of the deposited films was confirmed by evaluating the transfer ratio the UV absorption and the capacitance. The dielectric characteristics such as the frequency-capacitance characteristics and the dielectric dispersion and absorption characteristics of PA SA and AA through-plane were measured. The relative dielectric constants of PA, SA and AA LB films were about 3.0~4.6, 2.7~3.0 and 2.4~3.0 respectively. That is the relative dielectric constants were decreased in proportion to the chain length of methylene group. Also the dielectric dispersion and absorption of each fatty acid LB films have arisen from spontaneous polarization of dipole polarization in the range of 10$^4$~10$^{5}$ ［Hz］. The conductivity of PA, SA and AA LB films obtained from I-V characteristics were about 9$\times$10$^{-14}$ , 3$\times$10$^{-14}$ and 5$\times$10$^{-15}$ ［S/cm］. respectively. These results have shown the insulating materials and could control the conductivity y changing the length of methylene group. Also we have confirmed that the barrier height of fatty acid systems were almost the same ones obtained from dielectric characteristics.

• Polymer(Korea)
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• v.29 no.1
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• pp.81-86
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• 2005

In this study, waterborne polyurethanes were synthesized with poly(tetramethylene glycol) (PTMG), polycarprolactone PCL), dimethylol propionic acid (DMPA) and different molar ratio of chain extender. Particle size, polydispersity, thermal and mechanical properties of waterborne polyurethane were investigated. The particle size of waterborne polyurethane was in the range of 5∼200 nm and decreased with increasing the amounts of PCL and chain extender. Glass transition temperatures ($T_g$) were in the range of -70∼-45 ${\circ}C$ and increased with as PCL and chian extender (ED) contents increased. The $T_g$ of polyurethane prepared from the mixture showed similar trends as compared with those of in the same values of synthetic polyurethane using PTMG or PCL, respectively. Also, mechanical properties of mixed polyols (PTMG and PCL) were lower than those of PTMG and PCL, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.38-38
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• 2021

전 세계적으로 기후변화의 영향으로 인해 수문·기상 등 다양한 분야에서 심각성이 야기되고 있으며, 가뭄, 집중호우, 태풍 등과 같은 자연재해의 발생빈도와 피해가 증가하고 있다. 우리나라의 경우 봄철 가뭄의 발생빈도가 증가하고 있으며, 발생지역이 확산되는 추세이다. 증발산량(evapotranspiration)은 기상학과 수문학에 주요한 농업기상 매개 변수로 다루어지며, 작물의 생육·성장에 필요한 물 수요 및 관개용수 산정에 필요한 인자로 가뭄 분석에 활용하는 중요 인자들 중 하나다. 증발산량 자료 구축에는 증발산계 (Lysimeter)를 이용하여 현장 데이터를 실측하는 방법과 구조화된 알고리즘을 통해 증발산량을 산출하는 방법으로 나누어진다. 우리나라의 경우 증발산계가 설치된 지역이 많지 않고 분포도 조밀하지 않으며, 기상, 식생, 토지 피복 등 다양한 요인들의 영향을 받는 증발산량의 특성상 실측 데이터를 구축하는 것은 현실적으로 어렵다. 이에 물수지 기법, 기상 변수 기반 추정 등 간접적인 방법을 통해 증발산량을 추정하는 연구가 일반적으로 진행되고 있다. 이에 본 연구에서는 미국항공우주국 (National Aeronautics and Space Administration, NASA) 제트 추진 연구소 (Jet Propulsion Laboratory, JPL)의 The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS)에서 제공하는 위성영상 중 증발산량 데이터를 구축하였다. 구축한 ECOSTRESS 증발산량 적합성 확인을 위해, 청미천·설마천에서 제공하는 증발산량과 비교 및 검증을 실시하였으며, 시공간적 변동성 분석을 위해 통계적 방법을 이용하였다. 본 연구에서 도출된 증발산량의 시공간 변동성 결과를 통해 지역별 가뭄 분석의 기초자료로 활용될 수 있을 것으로 사료된다.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.200-203
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• 2004

In this study, it is examined the properties of flow and early strength of concrete according to superplasticizer. For this experiment, it is analyzed that the flow and strength properties according to the mixture factors, compared with naphthalene superplasticizer(normal & delay type) focused on polycarboxylate superplasticizer. (1) The slump loss of concrete used polycarboxylate superplasticizer showed $4\~8cm$, it is judged that slump loss according to the time lapse can be minimized. (2) The performance of polycarboxylate superplasticizer is about $70\%$ level of the normal naphthalene type, it is superior to the delay type, but the performance showed so lowly. The 28days, early strength didn't differ according to the kind of superplasticizer.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.212-215
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• 2004

While member sections of concrete structures of nuclear power plant are big, water-cement ratio is small. Consequently, the huge amount of heat generation and high viscosity could be occurred. These might reduce constructibility of nuclear power plant. In order to obtain improved concrete mix proportion on nuclear power plant structures, the properties of normal concrete is compared with self-compacting concrete. In addition, various mixes of self-compacting concrete utilizing polycarboxylic acid based admixture is mutually compared and estimated.

• Analytical Science and Technology
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• v.15 no.1
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• pp.36-42
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• 2002

The dissolved organic carbon extracted from groundwater is separated into humic acid and fulvic acid. They are characterized for their chemical composition, spectroscopic characteristics using UV/VIS, IR and solid state $^{13}C-NMR$ spectroscopy, proton exchange capacity and molecular size distribution. The results are comparable with the literature data. The study explains that the aquatic humic and fulvic acid in this experiment are site-specipic and polydisperse natural organic matter with considerable proton exchange capacity.

• Journal of the Korean Applied Science and Technology
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• v.17 no.2
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• pp.99-104
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• 2000

Physical properties and performance characteristics of sodium salt of several pure N-acyl amino acids made from glycine, dl-alanine, sarcosine, dl-valine, l-leucine, l-aspartic acid and l-lysine seven long chain fatty acids are reported. The effect of acyl chain length and the differences in the structure of constituent amino acid of seven homologous series of amide intermediate linked carboxylate surfactant of this class on the properties are discussed.