• 공업화학
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• 제10권2호
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• pp.275-280
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• 1999

일반적으로 셀룰로오스는 그 골격구조 안에 서로 다른 반응성을 갖는 3개의 히드록시기를 가지고 있다. 이 기능기에 trimethylsiloxyl-, vinyldimethylsiloxyl-, allyldimethylsiloxyl-, phenyldimethylsiloxyl-, 3,3,3-trifluoropropyldimethylsiloxyl-과 tris(trimethylsiloxy)siloxyl-기를 치환반응을 이용하여 도입하였다. IR, NMR, 그리고 원소분석을 이용하여 그 구조분석 및 치환도, 그리고 siloxylation agent의 반응성을 검토하였다. 치환도는 각각 2.5, 2.2, 2.1, 2.2, 2.6, 0.7이었다.

• Journal of Magnetics
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• 제14권2호
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• pp.86-89
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• 2009

Structural and magnetic properties of polycrystalline $CaFe_2O_4$ prepared by the solid state reaction method were studied using powder X-ray diffraction (XRD) and $M{\ddot{o}}ssbauer$ spectroscopy. The structure of $CaFe_2O_4$ belongs to an orthorhombic system (space group: Pnma) with the lattice parameters $a=9.2373\;{\AA}$, $b=3.0237\;{\AA}$, and $c=10.7124\;{\AA}$. Results of structural refinement indicate, however, that there are two slightly different iron sites in the sample. The $M{\ddot{o}}ssbauer$ spectrum at 4.2 K shows a hyperfine sextet with a hyperfine magnetic field and an isomer shift of 47.3 T and 0.36 mm/s, respectively. An examination of the spectrum revealed that the line widths of the spectral lines were not uniform. The degree of asymmetric line broadening decreases with increasing temperature, suggesting that the difference in the degree of crystalline distortions between two $FeO_6$ octahedra is eliminated as the temperature rises.

• 한국식품영양학회지
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• 제9권2호
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• pp.143-150
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• 1996

The studies was carried out to investigate ripening degree and functional properties of EMC produced with pancreatic protease and palatase ML. During production of EMC, the amounts of free amino acid and free fatty acid were increased with increasing the reaction time. The amount of total nitrogen(T-N) and water soluble nitrogen(WSN) were increased with increasing time. EMC had contents of 1.79eA T-N and 0.52o WSN at 60 min of hydrolysis time. SRI and FRI value had also a similar correlationship. On the gel filtration, 2 kinds of soluble proteining capacity was also shown in alkali solution. Furthermore the foaming stability had the same result as that of the solubility. The water absorption of EMC showed the highest level at pH 4.0 and 5.0.

• 한국세라믹학회지
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• 제13권4호
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• pp.25-35
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• 1976

Mullite was synthesized by using kaolin and $\alpha$-alumina, and halloysite and aluminum hydroxide as raw materials at the various temperature in the range of 1200$^{\circ}$-1750$^{\circ}$C. The degree of mullitization was measured respectively by a quantitative X-ray diffraction method and a chemical analysis method. The rate and the maximum degree of mullitization were found to increase with temperature . The reaction completed at 1600$^{\circ}$Cfor less than 30 minutes, and yielded 98% mulllite inpurity in the case of kaolin-Al(OH)3. TiO$_2$ up to 3% was added to the batches of kaolin-Al(OH)$_3$. the effect of addition on the mullitization was investigated and found to decrease the sintering temperature for the mullitization. The mechanism of TiO$_2$ addition on the formation of mullite was also discussed.

• 한국식품영양과학회지
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• 제24권3호
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• pp.427-433
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• 1995

The optimal condition for hydrolysis of oyster was evaluated with proteases using response surface methodology(RSM). Among 11 commerical proteases, APLTM 440 was selected as the suitable protease for producing oyster hydrolysate on the basis of cost per unit enzyme activity. The effect of autolysis on degree of hydrolysis in oyster was negligible comparing to that of APL 440 protease treatment. From RSM and ridge analysis, the conditions favoring the highest degree of hydrolysis were pH 9.95, 61.1$^{\circ}C$, 2.64 hr reaction time, 49.2% substrate, and 0.35% enzyme/substrate ratio. Oyster hydrolysate prepared under optimal conditions shwoed virtually 51.98% of hydrolysis.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제7권2호
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• pp.59-69
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• 2001

The purpose of this study is to provide a basic data for architectural planning on the wards and special quality of physical remedy spaces of geriatrics hospital. This research, to analyse dependency degree of inpatients in geriatric hospital, shows relativeness between remedy space and wards, and to show behavior of each patients reaction to there space. Result of interviewed inpatients who were sorted by age, sex, dependency degree, and days in hospital, suitable space programming is to need for physical and mental state. On the bases of survey and analysis, the basic data for planning and design the hospital for the elderly with dementia has been proposed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.267.1-267.1
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• 2013

In modern science and technology, the organization of building blocks, such as spherical particles and zeolite, is important to form a nanostructure. So, it is essential to develop methods for organizing them into large scale for many precise applications. Up to now, reflux and stirring is widely used method for organization of colloidal particles. However, because this method is hard to organize building block with high coverage and uniform orientation, it is necessary to research another method. In this work, we synthesized spherical silica particles using St$\"{o}$ber method and organized them on the glass which is coated with 3-chloropropyltrimethoxysilane (CP-TMS) and polyethyleneimine (PEI) using Sonication method. Although spherical silica particles are difficult to attach on the glass due to their small attachment site, we improved this problem by coating PEI. We introduced two mode of reaction promotion, sonication (SO) and sonication with stacking between the bare glass (SS), and investigated degree of coverage (DOC) and degree of close packing (DCP).

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.565-566
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• 2003

The clinical performance of light polymerized composite resins is greatly influenced by the quality of the light curing unit used. Commonly used halogen light curing units(LCUs) have some specific drawbacks such as decreasing light output with time. To overcome this, the blue LED LCUs are newly developed and introduced. The purpose of this study was to observe the reaction kinetics and the degree of polymerization of composite resins when cured by different light sources and to evaluate the effectiveness of the blue LED LCUs compared with conventional halogen LCUs.(omitted)

• Bulletin of the Korean Chemical Society
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• 제22권9호
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• pp.948-952
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• 2001

Periodic mesoporous organosilicas with rope-based morphology from a reaction gel composition of 1 BTME : 0.57 ODTMABr : 2.36 NaOH : 353 H2O were synthesized. While long rope-shaped product dominated in case of static synthesis condition , gyroid type products instead of rope shaped product appeared and rope shaped product disappeared with agitation. PMO with such a long rope shaped morphology is firstly reported. Additionally, various rope-based morphologies depending on the degree of bending, twisting, folding and winding of rope such as spirals, discoids, toroids, and worm-like aggregates were observed. White powdered products were characterized by X-ray diffraction, N2 sorption measurement, SEM and TEM. From XRD pattern and TEM image, ODTMA-PMO with hexagonal symmetry was identified. The pore diameter and BET surface area of ODTMA-PMO are $32.9{\AA}$ and 799 m2g-1 , respectively. Hexagonally arrayed channels run with long axis of rope and rope-based shapes with various degree of curvature, which was elucidated by using TEM images.

• Bulletin of the Korean Chemical Society
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• 제21권6호
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• pp.628-634
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• 2000

Crosslink is the most important chemistry in a rubber vulcanizate. Degree and type of crosslinks of the vulcanizate determine its physical properties. Change of crosslink density and deformation of a rubber vulcanizate by thermal aging were studied using natural rubber (NR) vulcanizates with various cure systems (conventional, semi-EV, and EV) and different cure times (under-, optimum-, and overture). All the NR vulcanizates were deformed by the thermal aging at 60-100 $^{\circ}C.$ The higher the aging temperature is, the more degree of the deformation is. The undercured NR vulcanizates after the thermal aging were deformed more than the optimumand overcured ones. The NR vulcanizates with the EV cure system were less deformed than those with the conventional and semi-EV cure systems. The deformation of the NR vulcanizates was found to be due to change of the crosslink density of the vulcanizates. The crosslink densities of all the vulcanizates after the extraction of organic materials were also changed by the thermal ging. The sources to change the crosslink densities of the vulcanizates by the thermal aging were found to be dissociation of the existing sulfur crosslink and the formation of new crosslinks by free sulfur, reaction products of curing agents, and pendent sulfide groups.