검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 239

        181.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The physical characteristics of polyurethane were examined by SEM, FT-IR tensile strength and mole % [NCO/OH]. Growing concerns in the environment-friendly architecture and public works have led to the development of solvent-free formulations that can be cured and foamed in air. Compared with general packing materials, this resin is much stronger in intensity and much longer in durability. Polyurethane foam resins were mainly composed of polyol, MDI, silicone surfactant, fillers, catalyst and blowing agent. The rigid foam of polyurethane in mechanical characteristics were due to chain extender and the increase of mole % [NCO/OH]. The change in the microstructure of polyurethane should be taken into account when considering the process of construction and durability through the polyurethane polymer resin in lots of industries.
        4,000원
        183.
        2005.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Cs 이온에 대해 선택성을 갖는 ferrocyanide-음이온 교환수지를 제조하여 모의 제 염폐액 내에 존재하는 Cs 이온에 대한 흡착실험을 수행하였다. 제조된 이온교환 수지가 citric acid를 주제염제로 하는 제염폐액 내에 존재하는 Cs+ 이온에 대한 흡착능력은 상용 양이온교환수지에 비해 4배 이상 효과적인 것으로 나타났다. 모의 제염폐액과 선택성 이온교환수지를 접촉시킨 후 360분이 경과하면 금속이온에 대한 흡착반웅이 평형에 도달하였다. 본 연구범위에서 Co 이온농도가 필요이상 증가하게 되면 Cs 이온의 흡착율은 감소하였다. 과산화수소와 히드라진을 사용한 선택성 폐 이온교환수지의 재생실험 결과 전기중성화조건을 만족시키기 위해 Cs 이온이 수지로부터 용출됨을 확인하였고 열화없이 재 사용가능성을 확인하였다.
        4,000원
        184.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dispersion stabilities and photocatalytic activities of rutile powders with unique nano-structure synthesized by homogeneous precipitation process at low temperature(HPPLT) have been investigated in the acrylic resin containing fluorostyrene in the range of mole. Isoelectric point of in the acrylic resin placed in the neutral region whereas that of in the water placed in the acidic region, indicating that zeta potential and agglomeration of powder is strongly dependent on the pH and the type of solvent. To prepare an adhesion, an acrylic resin containing fluorostyrene was synthesized by a radical polymerization. The adhesion of coating layer was increased with increasing fluorostyrene's contents without changing the dispersion stabilities and degrading photocatalytic properties
        4,000원
        186.
        2003.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        반응성 페놀수지 폐액을 처리하기 위해 중공사막 모듈을 이용한 투과증발 막 탈수공정을 연구하였다. 이 공정의 거동을 예측하기 위한 모사모델을 확립하였고 여기에 사용되는 중요 기본 파라메타들을 평판형 막을 사용하여 직접 구하여 사용함으로써 공정모사의 정확성을 얻을 수가 있었다. 이들을 모사치와 중공사 투과증발 막으로 부터 직접 측정한 각 투과특성들을 비교한 결과 서로 잘 일치함을 보여 본 모사모델의 타당성을 입증하였다. 사용된 중공사막은 중공사 안쪽에 활성층이 도포되어 있으며 공급액은 중공사 내부로 공급하였다. 공급액의 막내에서의 흐름속도에 따라 온도분포가 결정되며 이에 따라 막 투과특성이 달라짐을 모사결과로부터 얻을 수가 있었다. 공급액 온도증가는 막을 통한 탈수 투과 속도를 증가시킬 뿐 아니라 반응속도 증가로 인하여 물 생성속도도 증가시킴으로써 공급액 저장조 내의 수분 함량은 이들 상반된 공정들에 의해 결정이 됨을 보였다. 투과압력이 공급액 증기압보다 훨씬 작은 범위에서 증가할 경우 투과추진력인 공급액과 투과부의 투과물 활성도비 감소가 크지 않아 투과특성을 약간 저하시킨다. 그러나 투과압력이 공급액의 증기압에 접근할 경우 활성도비 감소가 현저하게 일어나 투과특성저하가 급격히 일어난다.
        4,200원
        187.
        2003.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        탈지대두박을 이용한 isoflavone의 분리 및 정제를 위한 최적 조건을 찾고자 absorption resin인 Amberlite XAD-1180를 사용하여 흡착제 활성화용매의 농도, 흡착된 isoflavone의 용출용매의 농도, 용출용매의 양과 용출속도, 시료와 흡착제의 비율 그리고 수지에 미치는 pH와 ion의 영향을 조사하였다. 수지의 활성화와 용출에는 Amberlite XAD-1180의 경우 methanol 75%로 활성화시켜 ethanol 80%로 용출시키는 경우가 가장 높은 값을 보였으며, 이때 사용하는 absorption resin은 isoflavone 흡착을 위해 사용한 단백질제거 탈지대두박용액양의 약 0.5배로, ethanol의 양은 단백질제거 탈지대두박용액 양의 4배를 사용하여 flow rate 12 mL/min의 경우가 적절한 조건임이 밝혀져 흡착제 사용이 isoflavone 함량을 최고 2~3배까지 향상시키는 결과를 보였다. 이때 분리된 isoflavone의 순도는 최고 40%까지 얻을 수 있었다. pH와 ion의 영향에서는 pH는 5.0, NaCl은 0.25 N 이하에서 isoflavone의 유출량이 높았다.
        4,000원
        190.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Granular Activated Carbon (GAC) has been proven to be an excellent material for many industrial applications. A systematic study has been carried out of the kinetics of physical as well as chemical activation of phenolic resin chars. Physical activation was carried out using CO2 and chemical activation using KOH as activating agent. There are number of factors which influence the rate of activation. The activation temperature and residence time at HTT varied in the range 550~1000℃ and ½~8 hrs respectively. Kinetic studies show that the rate of chemical activation is 10 times faster than physical activation even at much lower temperature. Above study show that the chemical activation process is suitable to prepare granular activated carbon with very high surface area i.e. 2895 m2/g in short duration of time i.e. 1 to 2 hrs at lower temperature i.e. 750℃ from phenolic resins.
        4,000원
        191.
        2003.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A series of micro- and mesoporous activated carbons were prepared from two kinds of phenolic resin using a metal treated chemical activation methodology. N2-adsorption data were used to characterize the surface properties of the produced activated carbons. Results of the surface properties and pore distribution analysis showed that phenolic resin can be successfully converted to micro- and mesoporous activated carbons with specific surface areas higher than 973 m2/g. Activated carbons with porous structure were produced by controlling the amount of metal chlorides (CuCl2). Pore evolvement depends on the amount of additional metal chloride and precursors used. From the SEM and EDX data, copper contents were shown to be most effected by the incremental addition of metal chloride.
        4,000원
        192.
        2003.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In polymer precursor based activated carbon, the structure of starting material is likely to have profound effect on the surface properties of end product. To investigate this aspect phenolic resins of different types were prepared using phenol, mcresol and formaldehyde as reactants and Et3N and NH4OH as catalyst. Out of these resins two resol resins PFR1 and CFR1 (prepared in excess of formaldehyde using Et3N as catalyst in the basic pH range) were used as raw materials for the preparation of activated carbons by both chemical and physical activation methods. In chemical activation process both the resins gave activated carbons with high surface areas i.e. 2384 and 2895 m2/g, but pore size distribution in PFR1 resin calculated from Horvath-Kawazoe method, contributes mainly in micropore range i.e. 84.1~88.7 volume percent of pores was covered by micropores. Whereas CFR1 resin when activated with KOH for 2h time, a considerable amount (32.8%) of mesopores was introduced in activated carbon prepared. Physical activation with CO2 leads to the formation of activated carbon with a wide range of surface area (503~1119 m2/g) with both of these resins. The maximum pore volume percentage was obtained in 3-20 a region by physical activation method.
        4,000원
        196.
        2001.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The epoxy resin materials used in outdoor high voltage equipments are required to have the high electric performance because of the miniaturization. The frequence dependence of the permittivity and the loss tangent have important information. In this paper we describe the frequency dependence of the permittivity and the loss tangent for epoxy resin filled with silica and the influence of filler shapes on the dielectric properties. The increment of tan δ in the low frequency region is caused by the increment of both the electrical conductivity and the polarization due to the shape of filler and the water absorbed in and near the interface between fillers and resins. The result of charge current and discharge measure, electric conduction is increased according to voltage.
        4,200원
        197.
        2001.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to its low density, good mechanical properties and chemical inertness, glassy carbon(GC) has been studied for appications in several fields. A raw thermosetting resin of furanic resin was polymerized with a curing agent of p-toluenesulfonic acid monohydrate. The maximum yield of GC was obtained at the curing agent content of 1.0 wt% in furanic resin. In order to make thick GC, the affect of graphite filler addition to the furanic resin was investigated. The density and electrical resitivity of GC after graphitization were 1.45 g/cm3 and 47 ×10-4 Ω · cm respectively and the amorphous structure of GC was confirmed by XRD profiles with very broad peaks comparable to those of graphite at 206˚ and 45˚.
        4,000원
        198.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyacetal resin is usually used to make molds, but it is difficult to achieve dimension accuracy during molding. Therefore it is usually necessary to cut the polyacetal resin after a molding process. Polyacetal resin is easily machining by standard machine tool. Acetal is also a thermal stable material which can be totted without coolant Another concern about the use of polyacetal resin is that it absorbs water easily, which also results in problems with dimension accuracy Therefore, in this study, the cutting resistance of water-absorbed polyacetal resin and its surface roughness after cutting in order to achieve the highest degree of accuracy in the cutting of polyacetal resin were investigated. Also, The Robust Design method uses a mathematical tool called orthogonal arrays to study a large number of decision variables with a small number of experiments. It also uses a new measure of quality, called signal-to-noise (S/N) ratio, to predict the quality from the customer's perspective. Thus, we have taken Taguchi's parameter design approach, specifically orthogonal array, and determined the optimal levels of the selected variables through analysis of the experimental results using S/N ratio.
        4,000원
        199.
        2001.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Composite adsorbents were prepared by mixing water plant sludge with phenolic resin having the ratio of 1 : 1, 1 : 2, and 1 : 3 respectively, curing from 100℃ to 170℃ under N2 atmosphere, and then activating with N2 at 700℃. Thermal property, specific surface area and morphology of the composite adsorbents as well as their precursors were measured by TGA, BET and SEM respectively. Removal efficiency of the composite adsorbents to NH4+ and TOC was compared with those of commercial zeolite and activated carbon. The adsorbents presented very promising TOC removal efficiency of 98%, which was identical level to that of commercial activated carbon while they displayed removal efficiency, only 32%, of NH4+. Therefore, this composite adsorbent considered as the alternative material of commercial activated carbon, used as an expensive removal agent of organic substances and THM in water treatment plant and it also suggested a possibility of practical application in other processes.
        3,000원
        200.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present research was undertaken to evaluate the possibility of water purification filter with activated carbon fibers (ACFs) using a very low cost precursor consisting of phenolic resin coated on glass fibers. The simplified procedure involving coating, curing and activation and a very low cost glass fiber as a raw material were adopted in order to reduce manufacturing cost. The breakthrough curves of the manufactured ACFs and the commercial activated carbon (AC, Calgon F-200) were investigated in the initial concentration range from 19 to 49 ppm for benzene, toluene and ethylbenzene. From breakthrough profiles, the manufactured ACFs had significantly faster adsorption kinetics than the AC. Especially the benzene breakthrough curves, the manufactured ACF (13 g of ACF with 32% of carbon on the glass) was over the limited level (5 ppb) after flowing of 32 l at initial concentration of 15 ppm, while the commercial AC was shown about 3 ppm in initial adsorption.
        4,000원