• 한국해양공학회지
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• 제1권2호
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• pp.123-129
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• 1987

Corrosion fatigue fracture of dual phase steel(SS41) and raw material steel(SS41) were investigated in 3.5% NaCl aqueous solution at PH 4,6,9 and 11. The fatigue limit of dual phase steel is increased approximately 1.8 times larger than that of raw material in air. The corrosion fatigue life of dual phase steel is about 5-10 times larger than that of raw material in 3.5% NaCl aqueous solution. The reduction of fatigue life is larger for the acidsalt solution than for the alkali salt solution. The reduction of stress level on the reduction ratio of corrosion fatigue life is large as pH 6-11. The reduction ratio of corrosion fatigue life of dual phase steel and raw material is nearly coincided at pH 2. While at pH4-2 the reduction ratio of corrosion fatigue life only depends on the corrosion effect. It has been found that the corrosion resistance effect of dual phase steel is smaller than that of raw material in corrosion fatigue crack propagation rate. As pH below 6 is changed, it can be clearly observed from raw material that the brittle intergranular fracture is characterized, and from the above result, the influence of corrosion of dual phase steel is small.

• 한국건설순환자원학회논문집
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• 제5권1호
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• pp.8-13
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• 2017

본 연구는 $CO_2$를 다량 발생시키는 시멘트의 사용량을 줄이기 위한 일련의 연구로서, 산업부산물인 고로슬래그 미분말을 다량 치환하고 기존 알칼리 자극제를 대체하여 전기분해한 알칼리 수용액을 사용한 하이볼륨 시멘트 경화체의 개발을 위한 기초적인 연구를 수행하였다. 즉, 일반적인 시멘트를 사용한 시험체와 고로슬래그 미분말 40%, 60%에 일반적인 물과 전기분해 알칼리 수용액을 사용한 시험체에 대하여 압축강도, XRD 및 SEM을 측정하였다. 그 결과, 고로슬래그 미분말을 사용하는 경화체에 있어서 알칼리 수용액을 사용할 시 강도가 증가하고 입자 표면에 수화물이 다량 생성되는 결과를 얻었다. 특히, 고로슬래그 미분말을 40% 치환하고 알칼리 수용액을 사용한 경우, 일반적인 시멘트 경화체 보다 높은 압축강도를 발현하였다. 그러나 본 연구는 재령 10일에 한정하여 실시한 연구로서, 고로슬래그 및 전기분해 알칼리 수용액을 사용한 시험체에 대한 추가적인 연구가 필요하다고 판단된다.

• Journal of Pharmaceutical Investigation
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• 제4권1_2호
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• pp.13-18
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• 1974

Data are present for the interaction of beta-cyclodextrin with 7 pharmaceuticals in aqueous solution. By means of the solubility method of analysis, definite interaction were found to occur with all the compounds tested. The amount of these pharmaceuticals in equilibrium with their respective solid phase increased progressively with beta-cyclodextrin. A concentration of 1.5 g of beta-cyclodextrin per 100 ml of water increased the solubility of most compounds tested (except one) by 15-120%. Hydrolysis in alkali solution of chrolothiazide was retarded in the presence of beta-cyclodextrin.

• 공업화학
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• 제10권6호
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• pp.907-912
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• 1999

본 연구는 유기산염 및 알칼리 원료를 사용해 야채 및 과일등에 잔류되어 있는 농약 및 유성오염의 제거효과를 GC와 세정력 측정장치를 사용해 조사했다. 일반적으로 잔류농약 등의 유성 오염원을 제거하기 위해서는 합성세제, 유기용제 등의 여러 방법이 있지만 본 연구에서는 특별히 식품첨가물 원료만 사용했다. 알칼리 수용액상에서 trisodium citrate를 사용했을때 가장 우수한 결과를 나타냈는데, 기존의 화학 합성세제와 비교했을 때 우수한 농약제거력이 나타났다.

• 상하수도학회지
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• 제30권3호
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• pp.293-297
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• 2016

This study was performed in order to obtain the effect of the compressive strength of the cured product with manufacturing conditions (amounts of fine aggregate and different types of alkali activator). Material which is the basis of the cured product was used for the blast furnace slag, which has a latent hydraulic activity. Consequently, when using sodium hydroxide as the alkali activator, it is possible to obtain a higher compressive strength than using the calcium hydroxide. And also, it can be added a 10% of fine aggregate with blast furnace slag to improve the compressive strength.

• 대한화학회지
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• 제39권7호
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• pp.524-529
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• 1995

pH 1에서 15-crown-5(SGBM)을 결합시킨 silica gel를 고정상으로 하는 액체 크로마토그래피을 이용하여 혼합 금속이온 용액으로부터 금속이온들의 분리효율을 결정하였다. 여러가지 SGBM-금속이온들간의 결합상수 및 분리인자들을 측정한 결과 그 순위는 Li(Ⅰ) < Sr(Ⅱ) < Na(Ⅰ) < Cu(Ⅱ) < Mg(Ⅱ) < K(Ⅰ) < Ca(Ⅱ) < Bi(Ⅲ) < Sb(Ⅲ)로 나타났다. 이러한 사실은 금속이온의 크기 효과 및 전자 밀도 효과에 의해서 결정됨을 알 수 있었으며, 또한 알칼리, 알칼리 토금속이온 및 $Cu^{2+}$이 혼합된 용액에서 $Sb^{3+}$의 분리효율이 다른 이온들에 비해서 훨씬 좋게 나타남을 알았다.

• 한국재료학회지
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• 제19권7호
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• pp.362-368
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• 2009

Ti scaffolds with a three-dimensional porous structure were successfully fabricated using powder metallurgy and modified rapid prototyping (RP) process. The fabricated Ti scaffolds showed a highly porous structure with interconnected pores. The porosity and pore size of the scaffolds were in the range of 66$\sim$72% and $300\sim400\;\mu$m, respectively. The sintering of the fabricated scaffolds under the vacuum caused the Ti particles to bond to each other. The strength of the scaffolds depended on the layering patterns. The compressive strength of the scaffolds ranged from 15 MPa to 52 MPa according to the scaffolds' architecture. The alkali treatment of the fabricated scaffolds in an aqueous NaOH solution was shown to be effective in improving the bioactivity. The surface of the alkali-treated Ti scaffolds had a nano-sized fibre-like structure. The modified surface showed a good apatite forming ability. The apatite was formed on the surface of the alkali treated Ti scaffolds within 1 day. The thickness of the apatite increased when the soaking time in a simulated body fluid (SBF) solution increased. It is expected that the surface modification of Ti scaffolds by alkali treatment could be effective in forming apatites in vivo and can subsequently enhance bone formation.

• 한국의류학회지
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• 제20권4호
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• pp.609-619
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• 1996

Polyethylene Terephthalate (PET) has been used as a mainstream fiber to make silklike fiber. The silky characteristics such as softness, dry touch feeling and flexibility can be obtained by weight reduction treatment. In aqueous alkali solution, the surface of PET is dissolved away and reduced in weight. The PET fiber, yarn and fabric become thinner and the gaps between fibers are wider. Its mobility is greatly improved without change of basic structures of the treated PET fibrics. The alkali treatment was conducted under the various experimental conditions such as alkali (NaOH) concentration, treatment time and temperature. As the weight loss increased, drapability improved and tensile strength remarkably reduced. When the PET fabrics lost 30% in their weight, drape coefficient lowered as much as 30oA and tensile stregth lowered as much as 50%. The weight loss over 30% brings great improvement in drapability and dyeability and significant decline in durability. By the alkali treatment, absorbency in spectrophotometer of dyed PET can be increased as much as 82% due to the increase of the surface area and formation of microvoids on the surface.

• 대한화학회지
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• 제32권5호
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• pp.501-506
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• 1988

본 연구에서는 알칼리화합물의 첨가가 Co/NaY촉매의 반응성과 선택도에 미치는 영향을 관찰하였다. 촉매는 제올라이트 NaY에 알칼리화합물을 첨가한 후 $Co_2(CO)_8$을 담지시켜 제조하였고, 온도 = 200∼$250^{\circ}C$, GHSV = 120∼$160hr^{-1}$, 압력 = 1atm, $H_2$/CO = 1 에서 반응하였다. 첨가된 알칼리이온의 염기도가 클수록 올레핀선택도, probability of chain growth(${\alpha}$), $CO_2$의 생성율은 증가하고 메탄의 생성율은 감소하였으며, 알칼리용액의 염기도가 클수록 반응활성은 증가하였다.

• 펄프종이기술
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• 제47권6호
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• pp.113-122
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• 2015

This study was carried out to investigate the characterization of cadmium adsorption by cellulose hydrogel and aerogel. Hydrogel and aerogel were made from ashless pulp dissolved in alkali hydroxide-urea aqueous solution and manufactured in film and bead types. After regeneration of cellulose, hydrogel went through the process of substitution of organic solvent and freeze-dry in order to make aerogel. SEM was used to analyze the microstructure of hydrogel and aerogel. Experiment was conducted in various concentrations and pH conditions to find out the characteristic of cadmium adsorption. After that, EDS was used to identify existence and distribution of cadmium in hydrogel and aerogel. The result from comparisons of cadmium adsorption shows that bead type aerogel has the maximum cadmium adsorption and film type hydrogel has the minimum cadmium adsorption.