• Bulletin of the Korean Chemical Society
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• v.14 no.2
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• pp.215-220
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• 1993

Experiment on isomorphous substitution of Al by Fe in sodalite framework was carried out using dry way method at 800-900$^{\circ}$C in nitrogen atmosphere. The substitution of Fe was possible up to 25 mole% with some deviation of symmetry in sodalite cage. The cubic unit cell parameter increased with increasing Fe content. It showed ionic semiconducting property, especially the highest conductivity and the lowest activation energy in 10 mole% Fe-substituted sodalite which could behave as a superionic conductor at above 400$^{\circ}$C. When more Fe was introduced into sodalite the electronic conductivity was improved at high temperature. But the relative electronic contribution was found to be lower compared with ionic contribution at high temperature. In infrared spectra some major absorption bands of sodalite shifted to lower wave numbers due to heavier Fe atoms substitution in Al lattice sites.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.190.1-190.1
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• 2003

A bioassay-guided fractionation of the stem bark extract of Eucommia ulmoides Oliver (Eucommiaceae) led to the isolation of three iridoid constituents, genipin (1), geniposide (3), geniposidic acid (4) as well as (${\pm}$)-guaiacylglycerol (2) and fatty acid mixtures as active ingredients of the extract responsible for the antitumoral property. The EtOAc soluble part and BuOH soluble part of the extract demonstrated a significant inhibition on the proliferation of cultured human tumor cells such as A549 (non small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system) and HCT-15 (colon) in vitro, whereas the remaining water soluble part exhibited a poor inhibition. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.202.2-202.2
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• 2003

A bioassay-guided fractionation of the whole extract of Viscum album (a parasitic plant : Loranthaceae) led to the isolation of two triterpenoidal components, oleanolic acid (1), ${\beta}$-amyrin acetate (2), homoflavoyadorinin B (3) as well as large quantity of free fatty acid mixtures as active ingredients of the extract responsible for the antitumoral property. The EtOAc soluble part and BuOH soluble part of the extract demonstrated a significant inhibition on the proliferation of cultured human tumor cells such as A549 (non small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system) and HCT-15 (colon) in vitro, whereas the remaining water soluble part exhibited a poor inhibition. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.340.1-340.1
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• 2002

Centella asiatica is an herbal plant used on different continents by diverse ancient cultures and tribal groups. Historically. the extract has been used as a wound healing agent, The extract has three different triterpenoid ingredients: asiaticoside. asiatic acid, and madecassic acid. It has been reported that its wound healing activity is associated with the modulation of collagen synthesis in the skin dermis. The wound healing property of the extract has led to its commercial introduction under the trade name, Madecrlssol. As part of our program toward the development of new wound healing agents. structere activity relationship (SAR) studies have been performed by modifying asiatic acid. In this communication. the SAR study of esiatic acid for the development of an efficient woind healing agent is reported.

• Journal of Pharmaceutical Investigation
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• v.39 no.3
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• pp.185-199
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• 2009

Using a strain-controlled rheometer [Advanced Rheometric Expansion System (ARES)], the steady shear flow properties and the dynamic viscoelastic properties of $Antiphlamine-S^{(R)}$ lotion have been measured at $20^{\circ}C$ (storage temperature) and $37^{\circ}C$ (body temperature). In this article, the temperature dependence of the linear viscoelastic behavior was firstly reported from the experimental data obtained from a temperature-sweep test. The steady shear flow behavior was secondly reported and then the effect of shear rate on this behavior was discussed in detail. In addition, several inelastic-viscoplastic flow models including a yield stress parameter were employed to make a quantitative evaluation of the steady shear flow behavior, and then the applicability of these models was examined by calculating the various material parameters. The angular frequency dependence of the linear viscoelastic behavior was nextly explained and quantitatively predicted using a fractional derivative model. Finally, the strain amplitude dependence of the dynamic viscoelastic behavior was discussed in full to elucidate a nonlinear rheological behavior in large amplitude oscillatory shear flow fields. Main findings obtained from this study can be summarized as follows : (1) The linear viscoelastic behavior is almostly independent of temperature over a temperature range of $15{\sim}40^{circ}C$. (2) The steady shear viscosity is sharply decreased as an increase in shear rate, demonstrating a pronounced Non-Newtonian shear-thinning flow behavior. (3) The shear stress tends to approach a limiting constant value as a decrease in shear rate, exhibiting an existence of a yield stress. (4) The Herschel-Bulkley, Mizrahi-Berk and Heinz-Casson models are all applicable and have an equivalent validity to quantitatively describe the steady shear flow behavior of $Antiphlamine-S^{(R)}$ lotion whereas both the Bingham and Casson models do not give a good applicability. (5) In small amplitude oscillatory shear flow fields, the storage modulus is always greater than the loss modulus over an entire range of angular frequencies tested and both moduli show a slight dependence on angular frequency. This means that the linear viscoelastic behavior of $Antiphlamine-S^{(R)}$ lotion is dominated by an elastic nature rather than a viscous feature and that a gel-like structure is present in this system. (6) In large amplitude oscillatory shear flow fields, the storage modulus shows a nonlinear strain-thinning behavior at strain amplitude range larger than 10 % while the loss modulus exhibits a weak strain-overshoot behavior up to a strain amplitude of 50 % beyond which followed by a decrease in loss modulus with an increase in strain amplitude. (7) At sufficiently large strain amplitude range (${\gamma}_0$>100 %), the loss modulus is found to be greater than the storage modulus, indicating that a viscous property becomes superior to an elastic character in large shear deformations.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1581-1585
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• 2012

Two pyridinecarboxamide dicyanidecobalt(III) building blocks and two mononuclear seven-coordinated macrocycle manganese(II) compounds have been rationally selected to assemble cyanide-bridged heterobimetallic complexes, resulting in three cyanide-bridged $Co^{III}-Mn^{II}$ complexes. Single X-ray diffraction analysis show that these complexes $\{[Mn(L^1)][Co(bpb)]\}ClO_4{\cdot}CH_3OH{\cdot}0.5H_2O$ ($\mathbf{1}$), $\{[Mn(L^2)][Co(bpb)]\}ClO_4{\cdot}0.5CH_3OH$ ($\mathbf{2}$) and ${[Mn(L^1)][Co(bpb)]\}ClO_4{\cdot}H_2O$ ($\mathbf{3}$) ($L^1$ = 3,6-diazaoctane-1,8-diamine, $L^2$ = 3,6-dioxaoctano-1,8-diamine; $bpb2^{2-}$ = 1,2-bis(pyridine-2-carboxamido)benzenate, $bpmb2^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate) all present predictable one-dimensional single chain structures. The molecular structures of these one-dimensional complexes consists of alternating units of $[Mn(L)]^{2+}$ ($L=L^1$ or $L^2$) and $[Co(L^{\prime})(CN)2]^-$ ($L^{\prime}=bpb2^{2-}$, or $bpmb2^{2-}$), forming a cyanide-bridged cationic polymeric chain with free $ClO_4{^-}$ as the balance anion. The coordination geometry of manganese(II) ion in the three one-dimensional complexes is a slightly distorted pentagonal-bipyrimidal with two cyanide nitrogen atoms at the trans positions and $N_5$ or $N_3O_2$ coordinating mode at the equatorial plane from ligand $L^1$ or $L^2$. Investigation over magnetic properties of these complexes reveals that the very weak magnetic coupling between neighboring Mn(II) ions connected by the diamagnetic dicyanidecobalt(III) building block. A best-fit to the magnetic susceptibility of complex ${\mathbf}{1}$ leads to the magnetic coupling constants $J=-0.084(3)cm^{-1}$.

• Journal of Life Science
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• v.25 no.8
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• pp.936-941
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• 2015

The principal objective of this fundamental research was to analyze the physicochemical changes and sensory properties of Dolsan leaf mustard pickles (DMP) for the development of low-salt pickles in order to contribute to the diversification of food. The DMPs were stored at −2℃ for 90 days, with salinity maintained at 1.63% to 1.85%. The pH was decreased during storage, and the acidity was gradually increased for up to 60 days of storage, after which it was increased rapidly to 1.10. The L-values (lightness) from the stems were decreased during storage. The a-values (greenness) were increased, while the b-values (yellowness) were decreased. It was shown that the DMP had a progressive browning phenomenon and the number of lactic acid bacteria gradually decreased. The sensory evaluation showed that crunchy textures were decreased and touch textures were increased at 30 days. Therefore, Dolsan leaf mustard is suitable as a material for low-salt pickles during storage for 90 days. The results of the analysis of the physicochemical and sensory properties indicate that the optimal storage for DMP was maintained for up to 30 days.

• Korean Journal of Materials Research
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• v.22 no.4
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• pp.195-201
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• 2012

$Ce^{3+}$-doped yttrium aluminum gallium garnet (YAGG:$Ce^{3+}$), which is a green-emitting phosphor, was synthesized by solid state reaction using ${\alpha}$-phase or ${\gamma}$-phase of nano-sized $Al_2O_3$ as the Al source. The processing conditions and the chemical composition of phosphor for the maximum emission intensity were optimized on the basis of emission intensity under vacuum UV excitation. The optimum heating temperature for phosphor preparation was $1550^{\circ}C$. Photoluminescence properties of the synthesized phosphor were investigated in detail. From the excitation and emission spectra, it was confirmed that the YAGG:$Ce^{3+}$ phosphors effectively absorb the vacuum UV of 120-200 nm and emit green light positioned around 530 nm. The crystalline phase of the alumina nanoparticles affected the particle size and the luminescence property of the synthesized phosphors. Nano-sized ${\gamma}-Al_2O_3$ was more effective for the achievement of higher emission intensity than was nano-sized ${\alpha}-Al_2O_3$. This discrepancy is considered to be because the diffusion of $Al^{3+}$ into $Y_2O_3$ lattice is dependent on the crystalline phase of $Al_2O_3$, which affects the phase transformation of YAGG:$Ce^{3+}$ phosphors. The optimum chemical composition, having the maximum emission intensity, was $(Y_{2.98}Ce_{0.02})(Al_{2.8}Ga_{1.8})O_{11.4}$ prepared with ${\gamma}-Al_2O_3$. On the other hand, the decay time of the YAGG:$Ce^{3+}$ phosphors, irrespective of the crystalline phase of the nano-sized alumina source, was below 1 ms due to the allowed $5d{\rightarrow}4f$ transition of the $Ce^{3+}$ activator.

• Clean Technology
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• v.25 no.4
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• pp.275-282
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• 2019

In this study, the extraction of Conger myriaster oil by using supercritical carbon dioxide (SC-CO₂) and organic solvent was investigated. The extraction conditions conducted for SC-CO₂ varied for pressure (25, 30 MPa) and temperature (45, 55 ℃), while the SC-CO₂ flow rate was kept constant during the experiment (27 g min^-1) and hexane was used as a conventional organic solvent. The extraction yield indicated that the best extraction condition would be SC-CO₂ at 55 ℃ and 30 MPa, resulting in the highest yield of 37.73 ± 0.14%. The oils were characterized for their fatty acid (FAs) composition using gas chromatography, while it was revealed that the major FAs were mystric acid, palmitoleic acid, oleic acid, electroosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The oxidation stability of the extracted C. myriaster oil was evaluated by measuring the acid value, peroxide value, and free fatty acid. The best oxidative stability was obtained from SC-CO₂ extracted oil at 30 MPa and 55 ℃. There was a significant difference in the color properties of the SC-CO₂ and hexane extracted oils, with the SC-CO₂ extracted oil showing better chromaticity than the oil extracted using hexane. Extracting oils from C. myriaster with SC-CO₂ could bring better economic benefits than using organic solvents. When supercritical carbon dioxide was used, there was no post-treatment process; thus, it was confirmed that this is a more environmentally friendly oil extraction method.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.6
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• pp.272-279
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• 2015

$Y_2O_3:Eu^{3+}$ is an excellent red-emitting phosphor, which has been widely used for display devices due to highly luminescent property and chemical stability. In this study, $Y_2O_3:Eu^{3+}$ red phosphors were prepared using the solid state reaction and RF thermal plasma synthesis. The particle size of $Y_2O_3:Eu^{3+}$ phosphors obtained by the solid state reaction varied from 10 to $20{\mu}m$, and 30~100 nanometer sized $Y_2O_3:Eu^{3+}$ particles were obtained from a liquid form of raw material through RF thermal plasma synthesis without an additional heat treatment. Photoluminescence measurements of the obtained $Y_2O_3:Eu^{3+}$ particles showed a red emission peak at 611 nm ($^5D_0{\rightarrow}^7F_2$). PL intensity of red nano phosphors prepared by RF thermal plasma synthesis was comparable to that of red phosphors prepared by the solid state reaction, indicating that nano-sized $Y_2O_3:Eu^{3+}$ red phosphors could be successfully synthesized using one-step process of RF thermal plasma.