• Journal of the Korea Concrete Institute
• /
• v.21 no.5
• /
• pp.557-563
• /
• 2009

This study is on the properties of inorganic porous calcium silicate material made from silica powder through the autoclaving curing, the results of this study should be utilized fundamental data for the development of noise reduction porous solid material using siliceous byproduct generated by various manufacture process. For the manufacture of autoclave curing specimen, various calcareous materials used and siliceous materials used silica powder. In this study, properties in density and compressive strength according to the change of W/B and C/S ratio, microscopy for the shape of pore, SEM and XRD for the examination of hydrate after autoclave curing are carried out respectively. The test results shown that the more slurry density decrease, the more W/B increase at the fresh state, this tendency shown similar to in hardened state. Among the specimens of C/S ratio, the compressive strength of C/S ratio of 0.85 gave the highest the compressive strength. In the results of XRD, tobermorite generated by autoclaving curing was created all of specimens regardless of C/S ratio. To ascertain pore structure, we compared with existing porous calcium silicate product(ALC, organic sound absorbing porous material). The results of microscope observation, pore structure of specimen of this study was similar to that of existing inorganic sound absorbing foam concrete. therefore, we could conformed a possibility of sound absorbing porous solid material on the basis of the results.

• Economic and Environmental Geology
• /
• v.43 no.1
• /
• pp.21-31
• /
• 2010

Mine and leachate waters were collected from the Okdong mine for study on reaction with oxidizing agents such as NaOCl and $H_2O_2$. The pH and EC of the mine and leachate waters are 5.77, 831 uS/cm, and 6.38, 1920 uS/cm, respectively. The concentrations of Mg, Mn, and Zn are 23.25 mg/l, 14.90 mg/l, and 22.99 mg/l for the mine water and 98.75 mg/l, 3.38 mg/l, and 6.16 mg/l for the leachate water. The concentrations of Mg, Mn and Zn decreased after the reaction with the oxidizing agents and mine water. The concentrations of Mg, Mn and Zn rapidly decreased when oxidizing agents increased. The saturation indices that were computed by visual MINTEQ for initial mine and leachate water were undersaturated with Mg, Zn and Mn compounds. The precipitates after the reaction with the oxidizing agents are composed mainly of mangano-calcite[(Mn, Ca)$CO_3$] with small amount of calcite-magnesian and calcite.

• Korean Chemical Engineering Research
• /
• v.50 no.1
• /
• pp.11-17
• /
• 2012

Disinfection of Escherichia coli (E. coli) in drinking water was investigated by using $TiO_2$ and $TiO_2-SiO_2$ based photocatalyst prepared by sol-gel method. The disinfection test was carried out in an annular flow reactor with circulating sterile water containing the photocatalysts powder under UV-A irradiation. The disinfection activity was proportional to the anatase`s intensity of crystalline peak of the $TiO_2$ photocatalysts. 100% disinfection of E.coli without endotoxin was achieved with $TiO_2$ coated photocatalytic system under UV-A irradiation within 2 h. However, toxic endotoxine was exist in the disinfection of E.colithe under UV-C irradiation even though 100% disinfection of E.colithe within 30 min, which suggest that $TiO_2$ coated photocatalytic system with UV-A is useful tool for the disinfection of E.coli in drinking water.

• Applied Biological Chemistry
• /
• v.20 no.1
• /
• pp.117-122
• /
• 1977

Development of new burning additives against nitrate salts used in past tobacco industry examined to reduce harmful nitrogenous compounds in smoke. Among several additives treated, the best effect by means of elevation of combustibility and reduction of tar and nicotin contents in smoke was observed by adding sodium citrate from 0.6 to 1% in tabacco. The following results were obtained through investigating combustibility, chemical composition, and differential thermal analysis of the tabacco treated with the buring additives. 1) The close relation was observed between the levels of the smoke components and combustibility of the treated tabacco. 2) Differential thermal analysis (D.T.A.) of citrate-treated tobacco shows an increase in H. Value and a decrease in L. Value as compared with other tobacco sample. 3) The D.T.A. of sodium-nitrate and sodium-citrate shows that sodium-nitrate gives endothermal reaction at $270^{\circ}$ and $310^{\circ}$ and sodium citrate gives exothermal reaction at $290^{\circ}$ with endothermal reaction at $170^{\circ}\;and\;310^{\circ}$. 4) $Na_3-citrate-treated$ tobacco shows an increase in smoke generation between room temperature and $350^{\circ}$ (Zone A) and a decrease in smoke generation between $350^{\circ}$ and $900^{\circ}$ (Zone B) compared with untreated tobacco. The smoke from these tobacco also contains lower levels of Tar, Nicotine, Phenols, Nitrogen oxides and Benzpyrene, and elevation of static Burning rate.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.43 no.2
• /
• pp.115-124
• /
• 2017

The objective of this study was to investigate skin whitening effect of Resorcinol dipentyl ether [1,3-di(pentyloxyl)benzene] by in vitro experiments. Resorcinol dipentyl ether was prepared by alkylation of resorcinol with 1-bromopentane. The reaction products were confirmed by NMR, MS and other analytical equipments. In order to evaluate the skin safety of resorcinol dipentyl ether, the cytotoxicity of the cells constituting the skin (keratinocyte, melanocyte, fibroblast) was analyzed and similar cell viability was observed in all cell lines as compared with the control group. Inhibition of extracellular melanin synthesis effect of resorcinol dipentyl ether was approximately 65.75% at $20{\mu}g/mL$ and inhibition of intracellular melanin synthesis effect of resorcinol dipentyl ether was approximately 53.89% at $20{\mu}g/mL$. The real-time PCR and western blot analysis of mRNA expression and protein expression of tyrosinase, TRP-1, and TRP-2 related to melanogenesis revealed that melanin inhibitory effect of resorcinol dipentyl ether was inhibited from the transcription stage respectively. Finally, this study suggested applicability of Resorcinol dipentyl ether [1,3-di(pentyloxyl)benzene] as a whitening functional cosmetic new material.

• Proceedings of the Ginseng society Conference
• /
• 1984.09a
• /
• pp.113-118
• /
• 1984

The effect of the saponin fraction extracted from Panax ginseng C.A. Meyer on the antioxidant activity of ${\alpha}-tocopherol$ was investigated in vitro as well as in vivo. Microsomal preparation of albino rat (Sprague-Dawley, 180-200g) was incubated in the mixture containing NADPH, $Fe^{3+},$ ATP, ${\alpha}-tocopherol$ with and/or without ginseng saponin fraction for 30 minutes and the malondialdehyde formed was assayed and found that the saponin fraction stimulated the antioxidant activity of ${\alpha}-tocopherol$ cooperatively. It was also realized that the cooperative stimulation of the antioxidant activity of ${\alpha}-tocopherol$ was most eminent when the concentration of the saponin fraction was around $10^{-5}\%$ in the reaction mixture. Alcoholic suspension of ${\alpha}-tocopherol$ with and/or without ginseng saponin fraction was administered orally to rats in which the lipid peroxidation was induced by ethanol administration and the lipid peroxide contents of the liver were assayed at certain periods of time after ${\alpha}-tocopherol$ administration in this animal. It was reported that the saponin fraction stimulated the absorption of ${\alpha}-tocopherol$ in rats and this was confirmed again in the present work. From the previous work and present experimental results, it seemed that the saponin fraction accelerated the absorption of ${\alpha}-tocopherol$ and therefore stimulated the antioxidant activity of ${\alpha}-tocopherol$ more effectively in the animal body.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.21 no.6
• /
• pp.686-692
• /
• 1992

The present study was carried out to examine the antioxidative actions between the products of amino-carbonyl reaction and commercial antioxidants, and investigate their synergistic effects. Nondialyzable melanoidins exhibited more significantly in the antioxidative action than unfractionated meanoidins did. Also, in the case of unfractionated melanoidins, both glycine and histidine were more effective than aspartic acid for the antioxidative action. There was no significant difference among amino acids in the action of nondialyzable melanoidins. The unfractionated melanoidin was not as good as antioxidative action of the synthetic antioxidants, butylated hydroxytoluene, tert-butyl hydroquinone and ascorbic acid ; however, the one was superior to that of natural antioxidants, ${\alpha}$-tocopherol and lecithin. Otherwise, the action of nondialyzable melanoidin was similar to that of synthetic antioxidant. The synergistic effects were increased in using melanoidin with ${\alpha}$-tocopherol and lecithin except for the systems of fructose-aspartic acid and fructose-glycine in unfractionated melanoidins.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.110-110
• /
• 2016

금속재료 중 철강은 기계적 성질이 우수하고 대량생산에 의한 뛰어난 경제성을 가지기 때문에 다양한 산업 분야에서 널리 사용되고 있다. 그러나 스테인리스강 등과 같은 일부 특수한 용도의 강을 제외하고는 부식 환경에 취약하기 때문에 그 용도에 따라 표면처리를 함으로서 내식특성을 부여하고 있다. 일반적으로 이러한 철강재료에 대한 부식문제를 해결하기 위한 방법으로는 습식프로세스 중 아연(Zn)도금이 사용되는데, 아연은 그 자체가 보유하고 있는 차폐(barrier)효과는 물론 상대적으로 이온화 경향이 크기 때문에 철에 대하여 전자를 공급하는 희생양극적(Sacrificial anode)역할을 하여 철을 방식하는 원리를 가지고 있다. 하지만 최근에 이르러 기존의 도금 프로세스 처리된 제품의 사용 및 적용분야가 확대되고 가혹해 짐에 따라서 내식성 향상을 위한 새로운 재료 및 신기술 개발이 요구되고 있는 실정이다. 본 연구에서는 친환경 프로세스 방법인 PVD법 중 하나인 스퍼터링(Sputtering)을 이용하여 0.8mm 두께의 냉연강판 (cold rolled steel) 상에 Al에 대한 Mg 함량을 10~30wt.%로 하여 약 $5{\mu}m$ 두께의 막을 제작하였다. 이때 20wt.% 막의 경우 공정압력조건을 증가시켜 증착 막의 결정배향성을 변화시켰다. 뿐만 아니라 제작된 막들에 대해서 $400^{\circ}C$온도에서 10분간 열처리함으로서 코팅막의 성분변화에 따른 영향을 살펴보기 위해 시편을 추가 제작하였다. 이와 같이 제작된 막들에 대한 형성메커니즘과 내식성의 상관관계 해명을 위해 막의 조성분포, 표면 및 단면의 모폴로지 관찰 및 결정구조 등 재료특성분석과 더불어 염수분무(Salt spray test), 침지시험 그리고 양극분극 시험 등을 통해 내식성 평가를 진행하였다. 이상의 종합적인 결과를 살펴보면 제작된 Al-Mg 막은 마그네슘 함량비 및 열처리 조건에 따라 조성분포와 막의 모폴로지 및 결정배향성이 변화한다는 것을 알 수 있었는데, 마그네슘 함량이 증가하고 열처리한 막의 내식성이 가장 양호한 것으로 나타났다. 이것은 Al-Mg 성분이 표면을 중심으로 균일 분산-분포하며, Al에 대한 Mg의 고용으로 인해 안정적으로 형성된 부식생성물과 금속화합물의 단계적 반응 효과에 의해 차폐효과와 희생양극적 특성이 동시에 향상되었기 때문으로 생각된다. 한편 공정 압력을 증가시켜 형성한 막은 결정학적 구조에서 보다 높은 표면 에너지와 증가한 격자 정수에 의해 Mg이 부식환경에서 빠르게 반응하여 안정적 피막을 형성하기 때문에 내식성이 향상된 것으로 보여 진다. 이상의 연구를 통해서 고내식성을 Al-Mg막의 유효성 확인하였으며, 설계에 대한 기초적인 응용지침을 제시할 수 있을 것으로 사료된다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.4
• /
• pp.409-416
• /
• 2017

1,2,3,4,6-Penta-O-galloyl-${\beta}$-D-glucose (PGG) is a gallotannin isolated from Galla Rhois. In a previous study, PGG was shown to suppress the allergic response by attenuating immunoglobulin E production both in vitro and in vivo. However, the effect of PGG on bacteria-induced inflammation at physiological concentration remains unclear. Therefore, the aim of this study was to investigate the effect of PGG on lipopolysaccharide (LPS)-stimulated macrophages. PGG inhibited release of nitric oxide (NO) and prostaglandin $E_2$ by alleviating protein expression of inducible NO synthase and cyclooxygenase-2 in LPS-treated RAW264.7 cells. Furthermore, PGG suppressed the release of interleukin-6 and tumor necrosis factor-${\alpha}$ induced by LPS. Further study indicated that PGG blocked translocation of the p65 subunit of nuclear factor-${\kappa}B$ from the cytosol into the nucleus, which is one of the underlying mechanisms of the anti-inflammatory action of PGG. Collectively, these data suggest that PGG might be useful for the treatment of inflammatory disease.

• Current Research on Agriculture and Life Sciences
• /
• v.16
• /
• pp.45-54
• /
• 1998

A thermotolerant bacterium, Streptomyces thermocyaneoviolaceus which produced xylan-degrading enzymes, utilized excellently xylan of wheat bran by producing the enzymes in comparison with that of birchwood or oat spelts. Optimal enzyme production was achieved in WB medium containing 0.8% wheat bran, 0.06% yeast extract, 0.06% bactopeptone, 0.05% $MgSO_4{\cdot}7H_2O$, 0.05% $FeSO_4{\cdot}7H_2O$, 0.05% $KH_2PO_4$ and, 0.2% $K_2HPO_4$(pH 7.0) at $50^{\circ}C$ for 24 hrs. The optimal pH and temperature for the hydrolysis of xylan were pH 5.5 and $65^{\circ}C$, respectively. The enzyme activity was retained more than 80% at the range from pH 4.5 to pH 9.5 at $4^{\circ}C$ for 12 hrs and 94% on the heat-treatment at $65^{\circ}C$ for 1 hr. Xylobiose, xylotriose, xylose, and other xylooligosaccharides were produced as end products from hydrolysis of birchwood xylan by the xylanase of S. thermocyaneoviolceus.