• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1169-1171
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• 2003

A stable derivative of L-ascorbic acid, 2-O-[(3-aminopropyl)phosphinooxy]-L-ascorbic acid (LAAP), was synthesized in moderate yield and its chemical stability and effects on melanin synthesis were investigated. LAscorbic acid was decomposed completely within about 1 hour, while 93% of LAAP remained even after 10 days. Treatment of L-ascorbic acid and LAAP decreased melanin content in normal human melanocytes to 33.8% and 49.1% of control at 2 mM, respectively. Considering chemical instability of L-ascorbic acid, LAAP is a much better whitening agent.

• 펄프종이기술
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• 제46권4호
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• pp.21-27
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• 2014

As a part of the study on manufacture of low density paper by organic bulky agent treatment, the effects of cationic fatty acid bulky agent on physical and optical properties of handsheets were elucidated. The research on change of physical and optical properties of paper samples according to bulky agent concentration, pulp type, and pulp combination were carried out. The results demonstrated that an increase of the concentration of cationic fatty acid bulky agent was proportional to an increase of the bulky properties of paper samples while tensile strength decreased. Also, the more the treated concentration of cationic fatty acid bulky agent increased, the more the ISO brightness of paper samples decreased while the opacity increased. The effectiveness of bulky agent with softwood bleached kraft pulp (SwBKP) was higher than that with hardwood bleached kraft pulp (HwBKP). In addition, the effectiveness with mixed pulps was higher than that with single pulp.

• 대한가정학회지
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• 제46권10호
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• pp.1-9
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• 2008

The purpose of this study was to increase uv-cut ability of cotton, ramie, and rayon fabrics dyed with safflower red colorants. For this purpose, samples treated with uv-cut agent and tannic acid were compared with the untreated samples after ultraviolet(uv)-light exposure in terms of K/S value, color changes(${\Delta}E$), SEM, and tensile strength retention. K/S value rapidly decreased with increasing exposure time, but K/S value of the samples treated with both uv-cut agent and tannic acid decreased less than that of untreated samples. As increasing exposure time, $L^*$ and $b^*$ increased, $a^*$ decreased, and so ${\Delta}E$ increased, indicating less red character and more yellow character in color. This leads to change hue, value and chroma value. But color change of samples treated with both uv-cut agent and tannic acid was less than that of untreated samples. SEM pictures showed a severe degradation by uv exposure in all samples. Tensile strength slowly decreased for 21 days. And after this point, the decreased proceeded more rapidly. Tensile strength retention of the samples treated with uv-cut agent and tannic acid was higher than that of untreated samples.

• Macromolecular Research
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• 제16권8호
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• pp.734-740
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• 2008

A new crosslinked, poly(acrylic acid)-based, dehydrating agent was synthesized through solution polymerization. The Taguchi method, a robust experimental design, was adopted to optimize the synthetic conditions based on the moisture and water absorbing capacities of the dehydrating agent. The method applied for the experiment was a standard L27 ($3^8$) orthogonal array with eight parameters and three levels. By analyzing the variance of the test results, the most effective parameters to control the moisture absorbing capacity (MAC) and its rate were the kind of alkaline base (LiOH, NaOH, or KOH) used as a neutralizing agent of the acrylic acid monomer and the degree of neutralization: The maximum MAC of 40% was achieved at only 2 hat $32^{\circ}C$ and 50% RH when KOH was used as a base and the degree of neutralization was 90%, respectively. However, the water absorbing capacity (WAC) of the resulting dehydrating agent was very low at 158 g/g, indicating that WAC is unaffected by MAC and its rate in this system. The surface morphologies of the agents were examined using scanning electron microscopy (SEM).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.117-118
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• 2011

The acid stained agents are able to make remarkably thin colored layers on concrete surfaces and have simple processes for applying them comparably. This study has examined properties of the reaction to acid stained agent and cement hydrate. We've observed that the C-S-W autoclave cured specimens contain less Calcium Hydroxide than the others and create tobermorite of C-S-H system crystalline and concluded that the reactions of acid stained agent become slowdown under C-S-W and cause light colors of specimens.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.417-421
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• 2003

The purpose of this paper is to study on the construction of roadbed with environmental friendly soil amendment agent. The special amendment agent used in this study is mainly composed of inorganic metal salts such as sodium chloride, magnesium chloride, potassium chloride, calcium chloride,, thus is friendly to the environment, and has a function of soil-cement-agent solidification. Various components of this agent weaken the negative function of humic acid and decompose humic acid itself. Then, the calcium cation of the cement can now be made contact directly to the soil surface. The project of local road demonstration of roadbed construction with special soil treatment agent was peformed in Northeast Thailand on August 1999 by the sponsor of Highway Department of Thailand. A series of field experiments including unconfined compressive strength were carried out to investigate the physical and mechanical characteristics of solidified roadbed treated by this solidifying agent. The results of this research showed that the roadbed using poor soil could be efficiently constructed by treatment of this amendment agent.

• Macromolecular Research
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• 제17권10호
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• pp.750-756
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• 2009

Stable, spherical, polystyrene particles were synthesized in ab initio dispersion polymerization by using the poly(methacrylic acid)[PMAA] macro-RAFT agent. The presence of the PMAA macro-RAFT agent on the polystyrene (PS) particles was confirmed by NMR and FTIR spectroscopy. The PS particle size was influenced by the concentration of the RAFT agent and monomer due to the initial nucleation. When the concentration of the PMAA macro-RAFT agent was increased from 2 to 10 wt% relative to the monomer, the average particle size decreased from 2.31 to 1.36 ${\mu}m$, the conversion decreased from 93.3 to 88.9%, the weight-average molecular weight increased from 46,300 to 150,200 g $mol^{-1}$ and the PDI decreased from 2.79 to 1.94, respectively. In particular, the incorporation of 10 wt% of PMAA macro-RAFT agent produced monodisperse PS spheres of 1.36 ${\mu}m$ with a coefficient of variation (CV) of 6.44%. Thus, the PMAA macro-RAFT agent worked as a reactive steric stabilizer providing monodisperse, micron-sized, PS particles.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1195-1198
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• 2000

In this paper, setting and strength properties of concrete with contents of super retarding agent are discussed. Gluconic acid and sucrose and used for super retarding agent. According to experimental results, as super retarding agent content increases, slump show to be increased, while air content decrease about 1~2%. In case of setting properties, as super retarding agent content increases, setting time delays considerable. When gluconic acid and sucrose is added about 0.3%, it delays more than 10days. Compressive strength of concrete of concrete with super retarding agent shows to be higher than that without it. Retarding of setting time of concrete using gluconic acid is longer than that using sucrose.

• 멤브레인
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• 제12권4호
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• pp.255-261
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• 2002

폴리비닐알콜을 고분자계 가교제인 폴리아크릴산-말레산 공중합체를 이용하여 가교제의 농도를 변화시키면서 가교하여 막을 제조하였다. 제조한 막은 FT-IR과 수팽윤도 측정을 통하여 가교반응을 확인하였으며, 가교제 농도 증가에 따라서 수팽윤도가 감소하는 경향을 나타내었다. 고분자가교제인 폴리아크릴산-말레산 공중합체로 가교된 폴리비닐알콜 막은 글루탈알데히드로 가교된 폴리비닐알콜이나 변성 폴리비닐알콜 막에 비해서 수팽윤도가 감소하였다. 이는 고분자가교제에 의한 화학적가교와 더불어 물리적인 가교효과가 증가하여 막의 팽윤을 억제하기 때문으로 사료된다. 에탄올수용액에 대한 투과증발실험 결과 가교제의 농도가 증가할수록 선택도는 증가하며, 투과유량은 감소하는 경향을 나타내었으며, 공급액 중의 물의 농도가 증가할수록 선택도는 약간 감소하나 투과유량은 급격히 증가하고, 공급액 중의 물의 농도가 증가하여도 가소화현상이 나타나지 않는 것을 관찰하였다. 이는 고분자가교제에 의한 팽윤억제 메카니즘이 작용하기 때문으로 사료된다.

• 한국염색가공학회지
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• 제15권6호
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• pp.27-32
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• 2003

As a natural antimicrobial agent, gallnut extract was examined. The extract was separated and analyzed by LC/MS to assign the components, gallic acid, digallic acid, trigallic acid, mono-galloyl glucose, penta-galloyl glucose, etc. Minimum inhibitory concentration of gallnut extract was about 10ppm. Cotton fabrics treated with 10% owf of gallnut extracts had antimicrobial activity showing the reduction of bacteria 99.9% for both Staphylococcus aureus and Klebsiella pneumoniae.