• 한국환경보건학회지
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• 제21권2호
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• pp.68-74
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• 1995

The optimum conditions was synthesized for the formation of Magnetite ($Fe_3O_4$) by air bubbling with the suspensions obtained by mixing Ferrous sulfate ($FeSO_4\cdot 7H_2O$) and Sodium Hydroxide (NaOH) solution in various values equivalent ratio($R=2NaOH/FeSO_4$) were studied. The changes of the structure were measured with XRD, $EM and BET. Equivalent ratio R: 0.65 was synthesized Goethite ($\alpha$-FeOOH), which becomes Maghemite ($\gamma=Fe_2O_3$) by dehydration, reduction and oxidation process. At the equivalent ratio over 1 (R>1), Magnetite ($Fe_3O_4$) was synthesized directly. The oxygen-deficient Magnetite ($Fe_3O_{4-\delta}$), which is obtained by flowing $H_2$ gas(100 ml/min) through the synthesis Magnetite at 350$\circ$C for 4 hr. By using it, was researched the decomposition reaction of $CO_2$. $CO_2$ was decomposed nearly 100% in 45 minutes by the oxygen-deficient Magnetite.

• 펄프종이기술
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• 제45권1호
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• pp.27-34
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• 2013

Quantitative analysis of 5-hydroxymethylfufural (5-HMF) conversion from fructose by dehydration and rearrangement was investigated by $^1H$-NMR spectroscopic method. Fructose was converted to 5-HMF in dimethylsulfoxide (DMSO)-$d^6$ or acidic deuterium hydroxide at controlled reaction temperature and time. With addition of internal standards (biphenyl for DMSO-$d^6$ solvent, and 2,5-dihydroxybenzoic acid for deuterium oxide solvent), conversion from fructose to 5-HMF was analyzed by $^1H$-NMR spectroscopy. Quantitative analysis was run by comparison with peak area integration between of 5-HMF and internal standard. In DMSO solvent, 5-HMF was stable end product but part of 5-HMF was converted to formic and levulinic acid at acidic aqueous medium.

• 한국세라믹학회지
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• 제33권12호
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• pp.1380-1386
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• 1996

The effects of urea addition and reaction conditions were examined in the prepareation of zirconia coated SiC whiskers through surface precipitation taking place during high-temperature aging of Zr(SO4)2 solutions containing the whiskers. More dense zirconia-hydrate was precipitated on the surfaces of the whiskers in the presence of urea. The ratio of the concentration of Zr(SO4)2 to the amount of added whiskers was the most important factor to confine the precipitation of zirconia-hydrate only at the surfaces of the whiskers The from of the coating layers was unchanged after heat-treatment leading to the dehydration and crystallization of the layers.

• 한국식품과학회지
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• 제17권2호
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• pp.55-59
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• 1985

생강으로부터 분리한 gingerol의 산화방지 효과에 대하여 시험하였다. 생강의 에탄올 추출물로부터 핵산-에테르 혼합용매를 이용하여 crude gingerol을 얻어 TLC에 의하여 gingerol을 분리.정제하였다. 분리한 gingerol은 발색반응, 산탈수반응, UV, IR 및 NMR 스펙트로메트리등을 거처 6- 및 10-gingerol임을 동정하였다. Gingerol은 리노레산-${\beta}$-카로틴-물의 메멀죤에 0.02%(w/v)농도로 첨가되었을 때 대조구에서보다 ${\beta}$-카로틴을 크게 안정화시켰다. 그러나 BHA 및 BHT보다는 그 효과가 약간 낮았다.

• 대한화학회지
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• 제25권1호
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• pp.44-49
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• 1981

Acetoacetanilide를 브롬화한 결과 예상한 ${\alpha}$-bromo 유도체가 얻어지지 않고, r-bromo 유도체가 얻어졌다. 이것을 mercaptoethanol과 반응시켜 sulfide 유도체를 만든다음, 산성하에서 고리화시킨 결과 2-(N-phenylcarbamoyl)methylene-1,4-oxathiane이 좋은 수율로 얻어졌다. 이 물질은 살균제 농약으로 널리 사용되고 있는 carboxin과 그 구조가 매우 유사하므로 이 물질의 biological activity는 흥미있는 과제가 될 것이다.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1628-1632
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• 2010

Porous ${\eta}-Al_2O_3$ was synthesized by modified sol-gel method using ionic liquid as a templating material. The addition of ionic liquid assisted to increase the surface area of alumina. However, the acidity of aluminas prepared with ionic liquids was hardly affected regardless the change of its structural properties. Among the ionic liquids used in this study, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][$PF_6$]) was the most effective ionic liquid to produce porous ${\eta}-Al_2O_3$ particles. The catalytic performance of these aluminas has been investigated in dehydration of methanol to produce dimethyl ether. The alumina prepared with [Bmim][$PF_6$] outperformed the other aluminas except ${\eta}-Al_2O_3$ without modification in this reaction.

• Bulletin of the Korean Chemical Society
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• 제24권10호
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• pp.1437-1443
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• 2003

Thermal decomposition of hydrated surface layer of $Mg(OH)_2$ at $500^{\circ}C$ in vacuum turned non-porous MgO into porous one with high surface area of around $270 m^2$/g. Most of its surface area, 74 %, was from micropores, and rest of it was from mesopores in wedge-shaped slits, exhibiting bimodal size distribution centered around 30 and 90${\AA}$. Rehydration followed by subsequent dehydration at $300 ^{\circ}C$ in dynamic vacuum further raised the surface area to 340 $m^2$/g. Fraction of microporous surface area was increased to 93%, and the shape of the mesopores was modified into parallel slits with a specific dimension of 32 ${\AA}$. Application of $Fe_2O_3$ over MgO via iron complex formation did not alter the pore characteristics of MgO core, except slightly increased pore dimension. Over the course of the modification, $Fe_2O_3$ stayed on the surface possibly via spill-over reaction.

• 한국환경보건학회지
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• 제19권4호
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• pp.44-50
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• 1993

This paper has concentrated on estimating the improvement of sludge dewaterability for the application of ozone in sewage treatment plant sludge. The experiment for the study was conducted by batch reactor, contacting ozone (5.0 g O$_3$/hr/l) to waste sludge and measured the Specific Resistance to Filtrate (SRF) varying pH, pressure and reaction time of ozone. And then checked the dissolved solids concentration of flitrate. The results of experiment were as follows: 1. When the total solids concentration of excess sludge was 9, 000 mg/l, the optimum injection rate of ozone was 5.0 g O$_3$/hr/l, and then pressure was 50 cm Hg for the measuring SRF. 2. In the range of pH 3~5, the effect of ozone injection was excellent, but it was unsatisfactory in the range of pH 9~11. Therefore, the ozone injection by acidifying pH level was effective in improving the dewaterability of sludge. 3. It was estimated that the dissolved solids concentration of flitrate was increased in proportion to the injection rate of ozone.

• The Korean Journal of Pain
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• 제18권1호
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• pp.56-59
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• 2005

The most effective treatment methods for a herniated lumbar disc remain questionable. This report follows the patients course, from the onset of pain through the completion of the non-surgical treatment, and shows that a lumbar herniated disc, with radiculopathy, can be successfully treated with a non-surgical approach. This report discusses the possible explanations for disc resorption: retraction into the intervertebral space, dehydration/shrinkage and resorption due to an inflammatory reaction. A non-surgical approach can be an effective treatment option for a herniated lumbar disc.

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.31-35
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• 1991

Three isomers of damascenone, odorous terpenic ketones, have been synthesized conveniently from a same starting material, ethyl 2,6,6-trimethyl-4-oxo-2-cyclohexene-1-carboxylate(1), which was easily available by the acid-catalyzed condensation of mesityl oxide or acetone with ethyl acetoacetate. ${\alpha}$-Damascenone(7) was prepared by converting the enone ester 1 into the corresponding tosylhydrazone(4), followed by treating with 4 molar equiv of allyllithium. ${\beta}$-Damascenone(12) was synthesized by chemoselective reduction of 1 with sodium borohydride/cerium chloride to give corresponding allylic alcohol 8, conversion of 8 into acetate 9, and thermal decomposition of 9 with DBU to afford ethyl ${\beta}$-safranate(10), followed by reaction with an excess amount of allyllithium. ${\gamma}$-Damascenone(15) was obtained by dehydration of 8 with boric acid to furnish ${\gamma}$-safranate(13), followed by treatment with 2 molar equiv of allyllithium.