• Food Science and Biotechnology
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• 제14권1호
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• pp.16-20
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• 2005

Additions of ground garlic, chili and ginseng powder did not affect the breaking force and strain of directly heated gel of Alaska pollack surimi. In comparison, these additives reduced the setting effect achieved by incubation of the salted surimi at $25^{\circ}C$, and resulted in a decreased breaking force and strain for the two step heated gel. Garlic almost completely inhibited the myosin cross-linking reaction, an important reaction for improving the gel properties occurring in the setting process. However, chili and ginseng powder minimally inhibited the cross-linking reaction. Thus, this study proposes that the mechanism for the suppression of the setting effect by chili and ginseng is different from that of garlic.

• Fibers and Polymers
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• 제2권3호
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• pp.135-140
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• 2001

Organic-inorganic hybrid composites consisting of poly(vinylidene fluoride) (PVDF) and SiO$_2$ were prepared through a sol-gel process and the crystallization behavior of PVDF in the presence of $SiO_2$ networks was investigated by spectroscopic, thermal and x-ray diffraction measurements. The hybrid composites obtained were relatively transparent, and brittleness increased with increasing content of tetraethoxysilane (TEOS). It was regarded from FT-lR and DSC thermal analyses that at least a certain interaction existed between PVDF molecules and the $SiO_2$ networks. X-ray diffraction measurements showed that all of the hybrid samples had a crystal structure of PVDF ${\gamma}$-phase. Fresh gel prepared from the sol-gel reaction showed a very weak x-ray diffraction peak near 2$\theta$=$21^{\circ}$ due to PVDF crystallization, and Intensity increased grade-ally with time after gelation. The crystallization behavior of PVDF was strongly affected by the amount of $SiO_2$ networks. That is, $SiO_2$ content directly influenced preference and disturbance fur crystallization. In polymer-rich hybrids, $SiO_2$ networks had a favorable effect on the extent of PVDF crystallization. In particular, the maximum portent crystallinity of PVDF occurred at the content of 3.7 wt% $SiO_2$ and was higher than that of pure PVDF. However. beyond about 10 wt% $SiO_2$, the crystallization of PVDF was strongly confined.

• International Journal of Industrial Entomology and Biomaterials
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• 제32권1호
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• pp.35-40
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• 2016

Hydrogels are crosslinked hydrophilic matrices for a variety of biomedical applications. Silk fibroin (SF), one of typical natural biomaterials, has been explored as base material for hydrogel. Photocrosslinked SF hydrogel containing poly(ethylene glycol) (PEG) was formulated through visible light initiated thiol-acrylate photopolymerization. The morphological, structural and thermal properties of SF - PEG hydrogel was investigated through scanning electron microscopy, X-ray diffractometry, thermogravimetry, and differential scanning calorimetry. The morphology of SF hydrogel showed dot and uneven surface with network cross-section. X-ray diffraction curves showed that the specific diffraction peaks of PEG were not changed by the intensity of the peaks were affected by sonication. Thermo-degradation behavior of SF - PEG hydrogel sonicated was significantly affected and became complex pattern compared to unsonicated ones. However, the melting endothermic temperature of SF - PEG hydrogel was not changed but the crystalline enthalpy was decreased by gelation and sonication.

• Macromolecular Research
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• 제16권3호
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• pp.189-193
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• 2008

Thermal cross-linking method of poly(vinyl alcohol) (PVA) using poly(acrylic acid) (PAA) was carried out on PVA/PAA hydrogels. The level of gelation was measured in the PVA/PAA hydrogels with various PAA contents. The swelling behavior at various pHs showed that the swelling kinetics and water contents of the PVA/PAA hydrogels reached equilibrium after 30 h, and the time to reach the equilibrium state decreased with increasing PAA content in the hydrogel. The water content increased with increasing pH of the buffer solution. The permeation and release of the drug were tested using indomethacin as a model drug. The permeated and released amounts of the drug increased with decreasing the PAA content because of the low free volume in the hydrogel due to the higher cross-linking density. The kinetic profile of drug release at various pHs showed that all samples reached the equilibrium state within the 5 h.

• 한국세라믹학회지
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• 제34권2호
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• pp.216-224
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• 1997

TEOS와 에탄올의 양을 고정하고 H2O/TEOS의 몰비가 2.6-59.0이 되는 범위에서 염산촉매를 사용하여 다공성 실리카 세라믹을 제조하였다. 서로 다른 조성의 솔 9종을 만든 후 젤화시간 측정, TG/DTA에 의한 건조시료의 열분석 및 FT-IR과 X-ray diffractometer에 의한 중간생성물의 특성분석을 수행하였고 50$0^{\circ}C$까지 열처리한 시료의 FT-IR에 의한 SiO2폴리머 분석, N2-adsorption isotherm을 이용한 비표면적과 기공크기분포 조사 및 TEM에 의한 SiO2폴리머의 형태와 기공의 변화를 조사하였다. 적용된 조성 및 촉매의 농도에서 최소 젤화반응시간은 TEOS1몰달 물의 양이 약 11몰에서, 가장 높은 중합도는 약 8-18몰에서, 그리고 가장 큰 비표면적값은 약 11몰에서 보였다. 이것은 물의 양이 약 11몰일 때 중합반응이 가장 빠르게 진행하였음을 의미한다. 결론적으로, 물의 양이 증가함에 따라서 약 11몰까지는 반응이 빠르게 진행되나 그 이상의 물이 사용될 경우 과잉의 물이 반응저해요인으로 작용하여 젤화시간의 지연 및 비표면적의 감소를 보인다.

• 한국수산과학회지
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• 제26권3호
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• pp.230-234
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• 1993

어육연제품의 제조시 가열에 의한 gel화 및 물성을 연구하기 위하여 differential scanning calorimetry(DSC)와 thermal gravimetric analyzer(TGA)에 의한 gel중의 물의 거동에 대해서 관찰한 결과를 요약하면 다음과 같다. DSC에 의한 물의 거동을 살펴본 결과, $105^{\circ}C$를 경계로 하여 속박상태가 다른 2가지의 물이 존재함을 알 수 있었으며, $R_{105}$값과 gel강도 간에는 높은 상관관계 (r=0.93)가 있었다. TGA에 의한 gel중의 물의 거동을 해석한 결과, 증발속도에 기인하는 3가지 상태의 물이 존재하였으며, 증발속도가 낮은(강하게 속박된) 물과 gel강도 간에는 아주 높은 상관관계(r=0.99)가 있었다. 이상의 결과로 미루어 보아 물의 존재상태와 물성 간에는 아주 깊은 상관성이 있어 물의 존재상태를 측정함으로써 그 물성을 예견할 수 있을 뿐만 아니라 보수력도 동시에 측정할 수가 있으므로TGA에 의한 해석은 어육 연제품의 물성을 연구하는 경우에 아주 유용한 수단으로 생각되었다.

• 한국분말재료학회지
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• 제18권2호
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• pp.129-134
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• 2011

Herein, macroporous carbon materials were readily prepared by carbonization of cured body of resorcinol and formaldehyde using poly(methyl methacrylate) colloid microspheres which were employed as the template in the gelation of resorcinol with formaldehyde. The gel in the water was solvent exchanged with methanol and the wet gel was dried. After carbonization of the template-gel composite at $800^{\circ}C$, it was found that pores were left corresponding to the size of the template, yielding carbon materials with a fine porous structure with enlarged surface area and significant porosity. Properties of the carbon foams including the structure, morphology, thermal stability, and porosity were investigated. Finally, it was concluded that the method using polymer colloids as the template provided a facile route to prepare carbon foams.

• 한국세라믹학회지
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• 제34권1호
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• pp.37-44
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• 1997

졸겔법중 딥코팅법을 이용하여 조성비 2Fe/Ba=5.25 졸로부터 바륨페라이트 박막을 제조하였다. 졸의 겔화과정은 4단계로 구분할 수 있으며, 8$0^{\circ}C$에서 90분간 반응시켜 제조한 졸이 코팅용 졸로서 가장 적합한 특성을 나타내었다. 박막층에 형성된 침상 형태의 입자들은 기판에 수평 하게 위치하고 있었으며, 박막 두께가 증가함에 따라 그 경향은 증가하였다. 침상형 입자의 자화용이축 방향은 장축 방향이었다.

• International Journal of Control, Automation, and Systems
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• 제2권2호
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• pp.135-143
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• 2004

Recently, high throughput screening for microorganisms with desired characteristics from a large heterogeneous population has become possible. Single cell separation has taken on increasing significance in recent years, and several different methods have been proposed so far. In this paper, we introduce several cell manipulation methods aiming at single cell separation and investigation. At first, methods for the separation of microorganisms are classified. Then, we introduce two different approaches, that is, (1) indirect manipulation using laser trapped microtools and (2) thermal gelation.

• Food Science and Biotechnology
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• 제14권6호
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• pp.871-874
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• 2005

The effect of rice starch at different concentrations (0, 4, 6, and 8%) on dynamic rheological properties of surimi sols was investigated by small-deformation oscillatory measurements at $10^{\circ}C$ and during heating from 10 to $95^{\circ}C$. Dynamic frequency sweeps at $10^{\circ}C$ showed that the magnitudes of storage modulus (G') decreased with increasing starch concentration while those of tan $\delta$ increased. G' values of surimi-rice starch sols during heating decreased with increasing starch concentration, indicating that the pattern of G' changes during heating was influenced by the concentration of the added rice starch. In general, the characteristic G' thermograms of all samples showed a similar sol-gel transition pattern.