From measured thermal conductivity and modeling by simulation, this study suggests that U-factors are highly related to materials used between steel and polymer. The objective and prospective point of this study are to relate the relationship between the U-factor and the thermal conductivity of the materials used. For the characterization, EDX, SEM, a thermal conductive meter, and computer simulation utility are used to analyze the elemental, surface structural properties, and U-factor with a simulation of the used material between steel and polymer. This study set out to divide the curtain wall system that makes up the envelope into an aluminum frame section and entrance frame section and interpret their thermal performance with U-factors. Based on the U-factor thermal analysis results, the target curtain wall system is divided into fix and vent types. The glass is 24 mm double glazing (6 mm common glass +12 mm Argon +6 mm Low E). The same U-factor of 1.45 W/m2·K is applied. The interpretation results show that the U-factor and total U-value of the aluminum frame section are 1.449 and 2.343 W/m2·K, respectively. Meanwhile, those of the entrance frame section are 1.449 and 2.

The hollow fiber membranes were prepared via hybrid process of the thermally induced phase separation(TIPS) and the non-solvent induced phase separation(NIPS). The spinning dope solution consisted of poly(vinylidene fluoride) (PVDF) / dibutyl phthalate (DBP) / 1-methyl-2-pyrrolidone (NMP), where DBP was used as a diluent and NMP as a solvent for PVDF. Various bore fluids were tested different ratio solvent/diluent mixture. Depending on the miscibility of dope solution and internal coagulant the samples underwent the different phase separation mechanisms and rates. Phase separation mechanism study for various combinations were performed to support the interpretation of the membrane structure. Membrane characterizations were performed such as water flux, porosity, pore size, and mechanical strength.

The hollow fiber membranes were prepared via hybrid process of the thermally induced phase separation(TIPS) and the non-solvent induced phase separation(NIPS). The spinning dope solution consisted of poly(vinylidene fluoride) (PVDF) / dibutyl phthalate (DBP) / 1-methyl-2-pyrrolidone (NMP), where DBP was used as a diluent and NMP as a solvent for PVDF. Bore fluids were tested different ratio solvent/ethanol and diluent/ethanol mixture. The membrane structure was analyzed by SEM and FT-IR to confirm phase separation mechanisms. Various structures were obtained due to the different phase separation mechanism. Membrane characterizations were performed such as water flux, pore size, rejection efficiencies and mechanical strength.

침지법을 이용한 상전이 공정으로 polysulfone (PSF), polyethersulfone (PES) and polyphenylsulfone (PPS)의 정밀여과 평막을 제조하였다. 용매로는 dimethyl formamide (DMF)를, 습윤제 고분자로는 polyvinylpyrrolidone (PVP)를 사용하였으며 pore 형성 촉매로 2-butoxyethanol (BE)을 사용하였다. 얻어진 분리막들은 SEM과 micro permporometer를 이용하여 morphology를 분석하였으며 순수투과도를 측정하여 분리막의 투과성능을 측정하였다. BE의 첨가를 통하여 분리막의 기공을 성장시킬 수 있었으며 고분자 구조에 따라 분리막의 morphology 변화를 관찰할 수 있었다. PSF, PES, PPS 분리막의 평균기공의 크기는 각각 0.282, 0.330, 0.308mum이었으며 공극률은 68.5, 66.1, 66.4%로 유사한 값을 나타내었다. 그러나 PPS 분리막의 경우 PSF, PES 분리막에 비해 높은 기공 밀도와 좁은 기공 분포를 관찰할 수 있었다. 그 결과 PPS 분리막의 순수 투과 유량은 357L/㎡ hr으로 PSF (196L/㎡ hr)나 PES membrane (214L/㎡ hr) 분리막에 비해 훨씬 증가함을 보였다.

This study was conducted to investigate the influence of natural degrading polymer film covering in rice paddies on the benthic macroinvertebrate community structure in Dangsu-dong, Suwon, Gyeonggi-do from May 2009 to September 2009. We compared 5 treatments: golden apple snail farming (GF), natural degrading polymer film + organic farming (NOF), natural degrading polymer film + chemical farming (NCF), conventional farming (CF)，and no fertilization (NF) as the control. The total number of species was highest in NOF followed by GF, NF, NCF, and CF. The total number of individuals was highest in NOF followed by NCF, CF, NF, and GF. The Dominance index (DI) ranged from 0.43 to 0.95. The highest dominance index was in GF followed by NCF, NF-CF, and NOF. The species diversity index (H") for each experimental plot ranged from 0.49 to 2.93. The average species diversity index was highest in NOF followed by NF, GF, CF，and NCF. After the natural degrading polymer film covered the paddies, the benthic macroinvertebrates tended to recover, but leeches and aquatic beetles increased, Mollusca and Annelida, which are sensitive taxa, decreased in both species and individual numbers after the soil was covered with the natural degrading polymer film. The number of species tended to recover. However, the number of individuals continued to decrease.d, especially individuals. Since then, the number of species tended to recover. However, the number of individuals decreased.

Chromium nitride (CrN) samples with two different layer structures (multilayer and single layer) were coated on bipolar plates of polymer electrolyte membrane fuel cells (PEMFC) using the reactive sputtering method. The effects with respect to layer structure on corrosion resistance and overall cell performance were investigated. A continuous and thin chromium nitride layer (Cr0.48 N0.52) was formed on the surface of the SUS 316L when the nitrogen flow rate was 10 sccm. The electrochemical stability of the coated layers was examined using the potentiodynamic and potentiostatic methods in the simulated corrosive circumstances of the PEMFC under 80˚C. Interfacial contact resistance (ICR) between the CrN coated sample and the gas diffusion layer was measured by using Wang's method. A single cell performance test was also conducted. The test results showed that CrN coated SUS316L with multilayer structure had excellent corrosion resistance compared to single layer structures and single cell performance results with 25 cm2 in effective area also showed the same tendency. The difference of the electrochemical properties between the single and multilayer samples was attributed to the Cr interlayer layer, which improved the corrosion resistance. Because the coating layer was damaged by pinholes, the Cr layer prevented the penetration of corrosive media into the substrate. Therefore, the CrN with a multilayer structure is an effective coating method to increase the corrosion resistance and to decrease the ICR for metallic bipolar plates in PEMFC.

The phase separated structure and the electro-optical properties of the (polymer/liquid) crystal : LC) composite film strongly depended on the weight fraction of LC in it. The continuous LC phase was formed in a three-dimensional polymer network when the LC weight fraction was above 40wt%. The aggregation structure of the composite film could be controlled by controlling the solvent evaporation velocity during the film preparation process. The smaller LC domains or channels were formed in the case of the faster solvent evaporation velocity. The composite film exhibited reversible light scattering-light transmission switching upon electric field -OFF and -ON states, respectiverly. The light scattering properties of the composite film strongly depended on the spatial distortion of the nematic directors as well as the mismatch in refractive indices between matrix polymer and LC.

폴리머시멘트 모르타르는 고강도 및 고내구성 등의 우수한 재료적 성질을 가지고 있어 철근콘크리트 구조물의 보수재료로 광범위하게 사용되어져 왔다. 폴리머시멘트 모르타르와 콘크리트 사이의 부착거동은 폴리머시멘트 모르타르에 의해 보수․보강된 철근콘크리트 부재의 보강성능을 좌우하는 매우 중요한 요소이다. 따라서 폴리머시멘트 모르타르와 콘크리트 접합면에서 발생되는 부착파괴의 메커니즘은 명확히 구명될 필요가 있다. 본 연구에서는 직접인발시험을 통해 국내에서 판매되는 폴리머시멘트모르타르와 콘크리트의 부착강도를 평가하였다. 표준, 침수, 온냉반복 및 동결융해 등의 전처리 조건에 노출된 폴리머시멘트 모르타르의 부착강도를 실내시험을 통해 평가하였으며, 2차에 걸친 시험시공을 통한 현장부착강도도 함께 평가하였다. 시험결과 현장부착강도는 표준조건에서 실시한 실내 부착강도 시험결과보다 낮은 수준이었으며, 열충격조건에서의 실내시험결과와 유사한 것으로 나타났다. 본 연구결과를 기초로 KS에 규정된 폴리머시멘트모르타르의 시험방법 및 품질기준의 타당성을 검토하였다.

수중구조물은 특수한 환경적 요인에 의하여 심한 열화상태에 놓이게 되며, 이러한 열화현상이 지속되게 되면 구조물은 철근의 부식과 콘크리트단면의 손실로 인하여 구조적으로 심각한 문제를 발생하게 된다. 수중구조물은 기중환경에서의 보수작업보다 매우 어려우며, 보수효과에 대한 증명도 불확실한 것이 현실이며, 기존의 보수공법은 외국의 사례를 보수효과의 검증없이 그대로 적용하거나, 경험에 의하여 시공되어져 왔다. 본 연구에서는 수중구조물에 대한 보수공법을 제안하고, 실험체의 거동특성과 보수재와 피보수재의 계면파괴를 관찰하여 제안된 보수공법의 효과를 비교 · 분석하였다.