• 한국응용과학기술학회지
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• 제30권1호
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• pp.9-15
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• 2013

A new process for the synthesis of polyphenylcarbosilane (PPCS) via thermal rearrangement of polymethylphenylsilane (PMPS) in supercritical cyclohexane was proposed and investigated at reaction temperatures of $380-420^{\circ}C$, reaction times of 1-2 h, and a pressure of 15 MPa. The structure, molecular weight, and molecular weight distribution of the product were characterized by FT-IR, Si-NMR, and GPC. The ceramic yield was also measured by TGA analysis. High-quality PPCS with high molecular weight and ceramic yield can be synthesized via a supercritical process. Furthermore, this process, when compared to the conventional method, tends to moderate the reaction conditions such as reaction temperature and time. It is concluded that thermal rearrangement in supercritical fluid is an efficient and viable process in terms of the resulting yield, efficiency, and reaction time compared with those of the conventional PCS production process.

• Nuclear Engineering and Technology
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• 제39권5호
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• pp.627-636
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• 2007

The present work is aimed at further discussing the effectiveness of dimensionless parameters recently proposed for the analysis of flow stability in heated channels with supercritical fluids. In this purpose, after presenting the main motivations for the introduction of these parameters in place of previously proposed ones, additional information on the theoretical bases and on the consequences of this development is provided. Stability maps, generated by an in-house program adapted from a previous application to boiling channels, are also shown for different combinations of the operating parameters. The maps are obtained as contour plots of an amplification parameter obtained from numerical discretization and subsequent linearization of governing equations; as such, they provide a quantitatively clear perspective of the effect of different boundary conditions on the stability of heated channels with supercritical fluids. In order to assess the validity of the assumptions at the basis of the in-house model, supporting calculations have been performed making use of the RELAP5/MOD3.3 computer code, detecting the values of the dimensionless parameters at the threshold for the occurrence of instability for a heated channel representative of SCWR proposed core configurations. The obtained results show reasonable agreement with the maps, supporting the applicability of the proposed scaling parameters for describing the dynamic behaviour of heated channels with supercritical fluids.

• 공업화학
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• 제16권2호
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• pp.169-179
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• 2005

다공성 소재는 바이오 및 전기전자소재 등 다양한 분야에 폭넓게 응용될 수 있다. 이러한 가공소재의 제조 및 공정은 주로 유기용매의 사용에 의해 이루어지고 있으나 유기용매는 대기 방출과 같은 많은 환경성 문제를 야기시키고 있다. 이에 반하여 초임계 유체는 기능성 기공 소재의 제조를 위한 대안 용매로서 수많은 물리적, 화학적 그리고 유독성 측면에서 유용한 장점을 보여주고 있다. 본 총설에서는 초임계 유체를 이용하여 나노/마크로 크기의 미세 기공구조 설계 및 형상 제어를 위한 공정 기술과 초임계 유체 내에서의 화학적 합성 반응을 통한 다공성 소재의 제조 기술을 소개하고자 한다.

• Preventive Nutrition and Food Science
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• 제13권1호
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• pp.12-17
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• 2008

Douchi, a popular seasoning agent in Chinese dishes prepared by the Aspergillus oryzae fermentation of black beans, was subjected to supercritical fluid extraction (SFE) and gas chromatography-mass spectrometry analysis for its volatile components. A total of 73 components were identified in two commercial brands, which were positively confirmed and quantified. Among the common components in the two brands were 18 acids, 12 alcohols, 11 aldehydes, 9 esters, 1 furan, 11 other oxygen-containing compounds, 4 pyrazines, 2 pyridines and 5 miscellaneous compounds. The most abundant components found were acetic acid, benzoic acid, 2,6-dimethylpyrazine, 2-piperidinone, 3-methylbutanoic acid, maltol, 4-ethylphenol, 2-methylpropanoic acid, butanoic acid, 2-pyrrolidinone, all fatty acids and some esters.

• 동의생리병리학회지
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• 제18권5호
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• pp.1391-1396
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• 2004

The purpose of this research was to investigate the effects of supercritical fluid extract of Kamichungbieum (SFE) on immune reaction. SFE did not affect the subpopulation of murine splenocytes and increased the production of interleukin-2 in serum. Also, SFE inhibited the influx of Ca/sup 2+/ into mast cells and the release of histamine from mast cells. Furthermore, SFE decreased the phagocytic activity of murine macrophages, These results indicate that SFE may be useful for the treatment of allergy related disease via inhibition of histamine release from mast cells and decrease of phagocytic activity of murine macrophages.

• 한국안전학회지
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• 제7권1호
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• pp.13-19
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• 1992

Supercritical fluid technology was applied to the regeneration of industrial catalyst contaminated with toxic materials. The regeneration process of activated loaded with phenol was proposed, then the adsorphon tower was packed with the activated carbon-bed. Phenol diffuses into supercritical carbon dioxide(SCC) through the micro-pore and voldge of the activated carbon. The saturated solubility of phenol in SCC depended on the density of SCC varing with temperature and pressure conditions. Therefore, the fasile phase equilibrium calculation model of dxpanded liquid One was proposed, and equilibrium solubility of phenol in SCC was calculated using the model theoretically. The regeneration mechanism of activated carbon was analysed by degree of saturation of phenol and diffusion in SCC. The solubility prediction was more satisfactory for the wide range of SCC density than the dense gas model and the desorption of phenol depended on the degree of saturation of phenol in SCC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.131-134
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• 1995

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.25-28
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• 1995

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.328.2-328
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• 2001

• 식품산업과 영양
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• 제10권3호
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• pp.22-29
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• 2005