• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.63-68
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• 2004

Sugar-based gelator p-dodecanoyl-aminophenyl- ${\beta}$-D-aldopyranosides (1-3) have been shown to self-assemble in the presence of p-aminophenyl aldopyranosides. The hydrogel 1+4 showed the double-helical structure with 3-25 nm outer diameters, which is quite different from that of 1. The gel 2+5 revealed twisted ribbon structure with 30-50 nm in widths and a few micrometers of length whereas the gel 3+4 revealed the single and the bundled fiber structures. The difference in these gel supramolecular structures has successfully been transcribed into silica structures by sol-gel polymerization of tetraethoxysilane (TEOS), resulting in the doublehelical, the twisted-ribbon, the single and the multiple (lotus-shaped) hollow fiber structures. These results indicate that novel silica structures can be created by transcription of various superstructures formed in binary gels through the hydrogen-bonding interaction, and the amino group of the p-aminophenyl aldopyranosides acts as an efficient driving force to create novel silica nanotubes. Furthermore, electron energy-loss spectroscopy (ELLS) provided strong evidence for the inner hollow structure of the double-helical silica nanotube. This is a novel and successful example that a variety of new silica structures can be created using a library of carbohydrate gel fibers as their templates.

• Journal of the Korean Chemical Society
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• v.34 no.5
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• pp.413-417
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• 1990

The structural variation process of amorphous SiO$_2$ gel upon heat-treatment conditions of 80, 250, 450 and 1000$^{\circ}C$ has been studied by using the radial distribution functions (RDF$_{obs}$) estimated from the X-ray diffraction intensities. The expected gel structure was determined by comparing the RDF$_{obs}$ with those for the other six standard samples selected appropriately. The structure of specimens prepared by sol-gel method is well consistent with that of fused SiO$_2$ (${\beta}$-cristobalite with cubic symmetry) except a slight difference in O-O band distance.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.2
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• pp.73-78
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• 2003

The influence of calcination temperature on the pore structure of freeze dried silica gel derived from tetraethyl orthosilicate (TEOS) was investigated using $N_2$adsorption and mercury intrusion techniques. Freeze dried material contained not only 4-6 nm sized mesopores and 6-10 $\mu\textrm{m}$ sized macropores, but minor micropores. The change of pore structure due to the increase of calcination temperature was dependant upon the degree of densification.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.185-191
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• 1984

The structure and textural properties of the traditional starch gel-form food Mook were investigated with the use of the Scanning Electron Microscope and Instron universal testing machine. Sensory evaluation was undertaken to evaluate the relationship between structure and textural properties of starch gel. When pure mungbean, potato, and sweet potato starches as well as 30% mungbean starches added to potato and to sweet potato starches were evaluated, it was found that mungbean starch gel had homogeneous and porous structure and showed the highest acceptability.

• Journal of Powder Materials
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• v.18 no.3
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• pp.269-276
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• 2011

The synthesis behavior of nanoporous silica aerogel in the macroporous ceramic structure was observed using TEOS as a source material and glycerol as a dry control chemical additive (DCCA). Silica aerogel in the macroporous ceramic structure was synthesized via sono-gel process using hexamethyldiazane (HMDS) as a modification agent and n-hexane as a main solvent. The wet gel with a modified surface was dried at $105^{\circ}C$ under ambient pressure. The addition of glycerol appears to give the wet gel a more homogeneous microstructure. However, glycerol also retarded the rate of surface modification and solvent exchange. Silica aerogel completely filled the macroporous ceramic structure without defect in the condition of surface modification (20% HMDS/nhexane at 36hr).

• YAKHAK HOEJI
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• v.8 no.2
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• pp.37-44
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• 1964

The relationships involving acid-consuming capacity and X-ray powder diffraction patterns of aluminum hydroxide gel were studied. The aging of antacid efficacy of aluminum hydroxide gel has also been characterized by using X-ray powder diffraction. The acid-consuming capacity decreased with progress of crystallization from amorphous alumino gel, and it was found that aged product at 80.deg. C had crystal structure of bohmite (.alpha.-Al.sub 2/O$_{2}$(OH)$_{2}$). It was also noted that the rate of aging decreased with decreasing pH of aluminum hydroxide gel.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.1
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• pp.85-92
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• 2021

The stratum corneum is formed from keratinocytes and intercellular lipids, with ceramide as the main component of intercellular lipids. Ceramides are one of the important components of the intercellular lipids to form a lamellar structure, but they are insoluble and therefore are not suitable for direct application to the skin. Thus, it was intended to apply ceramide to the formulation of pluronic lecithin organogel (PLO gel), which received constant attention among drug delivery systems. A suitable oil for formulation was selected and a PLO gel containing ceramide was manufactured. Liquid crystal formation and variation were observed using polarized microscopes, and viscoelastic analysis was performed to find out the viscoelastic behavior of the PLO gel. Small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) analysis were performed to confirm the structures in the formulation. Results showed that the size and stability of the liquid crystal differed depending on the content ratio of ceramide and lecithin in the PLO gel containing ceramide. Furthermore, viscoelastic analysis showed the stability of the formulation, and SAXS/WAXS analysis confirmed that the PLO gel without ceramide had hexagonal structure of the quadrilateral system array, and the PLO gel with ceramide had the lamellar structure of the quadrilateral system array.

• YAKHAK HOEJI
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• v.25 no.4
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• pp.175-179
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• 1981

Rheological studies on the gelatin hydrogels were carried out by rheometer. In the temperature range of $32^{\circ}~90{\circ}C$, the viscosities of the gelatin hydrogels were measured. In order to observe the formation of gel structure, the stress-relaxation tests of the creep-curves were investigated. The structure of viscoelastic substance could be considered of a three dimensional crosslinked matrix. As the result viscoelastic coefficients were obtained by Maxwell element, which are correspond to the network structure. From the relationship between the stress-relaxation time and temperature, activation energy correspond to breaking the formation of gels was calculated to be 13.91kcal/mole.

• Membrane and Water Treatment
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• v.8 no.6
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• pp.543-551
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• 2017

Membrane fouling in membrane bioreactor (MBR) remains a primary challenge for its wider application. The focus of this study to investigate the influence of iron distribution in activated sludge on gel layer fouling in MBR. Significant reduction in the transmembrane pressure (TMP) rise rates was observed in the presence of iron as result of retarding the gel layer formation time. The spatial distribution of iron had a significant impact on the stratification structure of extracellular polymeric substances (EPS) fractions, such as proteins (PN) and polysaccharides (PS). A mitigation of PN or PS from the supernatant to the EPS inner layers was observed in the presence of iron. Compared with the control reactor, the reduction in PN and PS of the supernatant and lower PN/PS rates of the LB-EPS were beneficial to decrease the membrane fouling potential during the gel layer formation. Consequently, the iron addition managed to control gel layer fouling could be a useful strategy in MBR.

• Journal of Powder Materials
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• v.18 no.2
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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.