• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.4
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• pp.419-425
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• 2018

In this study, cross-linked collagen gels were successfully prepared with varying of elastic modulus from 0.7 to 17.7 kPa using a chemical cross-linker. Then, human dermal fibroblasts were encapsulated into the porous pores introduced into the gels, and cell growth and behavior were examined by gel's mechanical properties. Specifically, increasing elastic modulus of the gel led to decreases in procollagen synthesis from 47 to 32 ng. In addition, there could be optimum elastic modulus for procollagen production, when the gels were treated with adenosine. However, interestingly, this study discovered that the procollagen production level was not influenced by the elastic modulus of the gel for functional peptide. In conclusion, these results would be highly useful for designing reconstructed skins with varying of elastic modulus to examine functional materials in cosmetics.

• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.59-63
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• 2021

This study presented the characteristics and additive effects of the grout with mixing ratio for developing of high-efficiency grouting technology under high depth conditions. The laboratory investigation were conducted with Portland cement (OPC) and micro cement (S8000-E) including viscosity experiments, particle size analysis experiments, Gel-Time experiments and uniaxial compressive strength experiments. As a result of the viscosity experiment, it was shown that OPC is advantageous in terms of viscosity, but S8000-E is suitable when considering the passage of rock joint intervals through particle size analysis. The Gel-Time experiment shows that it is not that difficult with injection as a grout material even when silica fume (SF) was applied. The strength of the cured material is improved as increase in the content of silica fium (SF). Within the range of the study, the optimal mixing ratio obtained through various experiments is S8000-E, w/c=70%, silica fium (SF)=6%, and 7 days.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.523-530
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• 2022

The problem in the construction of seawall reinforcing the seawall where there is seawater flow is the outflow of materials. Gravity-type pouring of concrete is difficult to fill the voids smoothly, and the cement of concrete that has not hardened is likely to be dispersed in seawater. This phenomenon not only reduces the reliability of quality after concrete hardening, but can also adversely affect the surrounding environment. Therefore, there is a need for a gel-like injection material that can be injected, In this study, the initial strength and durability improvement effect of seawater immersion were evaluated by using electrofurnace reduction slag and blast furnace slag with acute properties. As a result of the experiment, it was possible to prepare a gel-like injection material having flowability through reaction with silica-based chemical liquid. The flowability of the gel is 105~143 mm depending on the formulation, and the on-site simulation test can fill the voids without external leakage, confirming its on-site applicability.

• Clinical and Experimental Vaccine Research
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• v.11 no.1
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• pp.30-42
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• 2022

Purpose: The key objective of this study was to formulate a local combined inactivated gel adjuvanted vaccine containing bovine viral diarrhea virus (BVDV)-1, BVDV-2 viruses and Clostridium perfringens type A toxoid. The study evaluated its ability to enhance protective active immune response in camels' calves against these infectious pathogens under field conditions. Materials and Methods: The local BVDV cytopathic strains and a local strain of toxigenic C. perfringens type A were used in vaccines formulation. Vaccines A and B were monovalent vaccines against C. perfringens and both strains of BVDVs, respectively. While the vaccine C was the combined vaccine used against the three agents. All vaccines were adjuvanted with Montanide gel. Sterility, safety, and potency tests were applied on the formulated vaccines. Virus neutralization and toxin anti-toxin neutralization tests were used to evaluate the immune responses. Results: Both monovalent (vaccine A) and combined vaccines (vaccine C) showed a protective level (4.5 and 3 IU/mL, respectively) against C. perfringens from the 2nd-week post-vaccination. The titer declined to 3 and 2 IU/mL, respectively at the 5th-month post-vaccination. The titer against BVDV, the monovalent vaccine (vaccine B) reached the beak (1.95 IU/mL) at the 1st-month post-vaccination and lasted till 6th-month post-vaccination (0.92 and 0.94 IU/mL) for BVDV-1a and BVDV-2, respectively. Conclusion: Vaccination of camels with the combined vaccine adjuvanted by Montanide gel containing C. perfringens type A toxoid and BVDV strains with 6-month intervals is recommended to protect camels safely and efficiently against such infections in the field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.422-422
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• 2009

Photocurable inorganic-organic hybrid materials were prepared from colloidal-silica nanoparticles synthesized through the solgel process and using acryl resin. The synthesized colloidal-silica nanoparticles had uniform diameters of around 20 nm, and they were organically modified, using methyl and methacryl functional silanes, for efficient hybridization with acryl resin. The organically modified and stabilized colloidal-silica nanoparticles could be homogeneously hybridized with aeryl resin without phase separation. The successfully fabricated hybrid materials exhibit efficient photocurability and simple film formation due to the photopolymerization of the organically modified colloidal-silica nanoparticles and acryl resin upon UV exposure. The fabricated hybrid films exhibit an excellent optical transmission of above 90% in the visible region as well as an enhanced surface smoothness of around 1 nm RMS roughness. In addition, the hybrid films exhibit improved thermal and mechanical characteristics, much better than those of acryl resin. More importantly, these photocurable hybrid materials fabricated through the synergistic combination of colloidal-silica nanoparticles with acryl resin are candidates for optical and electrical applications.

• Computers and Concrete
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• v.32 no.6
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• pp.567-576
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• 2023

In this study, a 3D microstructure-based model is established to simulate the effective thermal conductivity of cement paste, covering varying influencing factors associated with microstructure and thermal transfer mechanisms. The virtual cement paste divided into colloidal C-S-H and heterogeneous paste are reconstructed based on its structural attributes. Using the two-level hierarchical cement pastes as inputs, a lattice Boltzmann model for heat conduction is presented to predict the thermal conductivity. The results suggest that due to the Knudsen effect induced by the nanoscale pore, the thermal conductivity of air in C-S-H gel pore is significantly decreased, maximumly accounting for 3.3% thermal conductivity of air at the macroscale. In the cement paste, the thermal conductivities of dried and saturated cement pastes are stable at the curing age larger than 100 h. The high water-to-cement ratio can decrease the thermal conductivity of cement paste.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.5
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• pp.241-246
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• 2012

$Yb^{3+}$, $Er^{3+}$ co-doped $SrMoO_4$ ($SrMoO_4$ : $Yb^{3+}/Er^{3+}$) specimens have been successfully synthesized via the complex citrate-gel method and their structural and optical properties were investigated in detail. Under 980 nm excitation, $SrMoO_4$ : $Yb^{3+}/Er^{3+}$ UC phosphors have been emitted strong green luminescence at 530 and 550 nm with weak red emission around 670 nm corresponding to the intra 4f transitions of $Er^{3+}$ ($^4F_{9/2}$, $^2H_{11/2}$, $^4S_{3/2}$) ${\rightarrow}$ $Er^{3+}$ ($^4I_{15/2}$). The optimal doping concentrations of $Er^{3+}$ and $Yb^{3+}$ ions were verified to 2/16 mol% and a possible upconversion mechanism depending on pump power dependence is studied in detail.

• Korean Journal of Materials Research
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• v.19 no.10
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• pp.555-561
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• 2009

Expanded graphite (EG) is synthesized by chemical intercalation of natural graphite (NG) and rapid expansion at high temperature, with titanium n-butoxide (TNB) used as titanium source by a sol-gel method to prepare EG-TiO$_2$ composite. The performances of the prepared EG-TiO$_2$ composite are characterized by BET surface area measurement, scanning electron microscopy (SEM), X-ray diffraction patterns (XRD) and energy dispersive X-ray analysis (EDX). To compare the photocatalytic activities of the EG-TiO$_2$ composite, three kinds of dye solutions, methylene blue (MB), methylene orange (MO) and rhodamine B (RhB), and two kinds of light source, UV light and visible light (VL), are used. Comparing the results, it can be clearly seen that the degradation of all of the dye solutions under irradiation by UV light is much better than that under irradiation by visible light, and the decomposition of MB solution was better than that of both of MO and RhB solution.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.571-576
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• 2011

Activity carbon (AC), Cu and $Cu_2O$ modified $TiO_2$ composites (Cu/$Cu_2O$-AC/$TiO_2$) were prepared using a sol-gel method. The characteristics of the composites were evaluated using Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of MO was determined using UV/Vis spectrophotometry. $Cu_2O$, Cu and the cooperative effect of the AC increased the photo-absorption effect, thus increasing in photocatalytic activity.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.269-274
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• 2013

ACF and ZnO modified $TiO_2$ composite materials (ZnO-ACF/$TiO_2$) were prepared by a sol-gel method. The composites were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of the MO was determined using UV spectrophotometers. An increase in the photocatalytic activity was observed and attributed to an increase of the photo-absorption effect by the ZnO and the cooperative effect of the ACF.