• Applied Biological Chemistry
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• v.28 no.1
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• pp.19-27
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• 1985

The physicochemical properties of starch isolated from Yullmoo (Coix lachrymajobi var. mayuen stapf.) and Yeomjoo (Coix lachryma-jobi L.) were investigated. The average diameters of starch granules of Yullmoo and Yeomjoo were 12.0 microns, both of all, and the shape of these starch granules were hexagon, octagon and round. X-ray diffraction patterns of two samples were A-types and amylose contents of Yullmoo and Yeomjoo starch were 0% and 23%, respectively, iodine affinities of these were 0.08% and 4.2%, respectively, blue values and alkali numbers of these were 0.13 and 0.43, 2.4 and 7.2, and raising power of these were 280 and 20, respectively. Yullmoo starch had higher swelling power than Yeomjoo starch. The increase in optical transmittance of 0.1% suspensions of Yullmoo and Yeomjoo starches occurred at $60^{\circ}C$ and continued up to $75^{\circ}C$ for Yullmoo, $85^{\circ}C$ for Yeomjoo. Amylogram data on 5% of Yullmoo and Yeomjoo starch suspensions showed that gelatinization temperatures and maximum peak heights of Yullmoo and Yeomjoo were $68.5^{\circ}C\;and\;78^{\circ}C$, 920 and 310 B.U., respectiyely. Intrinsic viscosities of Yullmoo and Yeomjoo starches were 1.49 and 1.77, respectively, and interaction coefficients of the two starches were 0.57 and 0.56, respectively The extent of retrogradation determined at $2^{\circ}C$ showed that retrogradation occurred slowly with Yullmoo starch paste tut little with Yullmoo.

• Polymer(Korea)
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• v.36 no.4
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• pp.420-426
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• 2012

In this study, we prepared polymer micelles containing quercetin and rutin, known as antioxidants, using poly(${\varepsilon}$-caprolactone)-b-poly(ethylene glycol), and evaluated in vitro skin permeation of the active materials. Quercetin and rutin loaded micelles were characterized by DSC (differential scanning calorimetry), HPLC (high performance liquid chromatography) and DLS (dynamic light scattering) measurements. The particle size of the polymer micelles increased in a concentration dependent manner (0.5~2.0% PCL-b-PEG). The Zeta potential of quercetin and rutin loaded micelles remained constant. To evaluate the skin penetration of PCL-b-PEG micelles, Franz diffusion cell experiment was performed. The aqueous solutions of quercetin and rutin were used as the control groups. Quercetin and rutin loaded PCL-b-PEG micelles showed more efficient skin permeation than the control groups. Safety assessment (patch test) of quercetin and rutin loaded PCL-b-PEG micelles on skin was performed to test application possibility of the polymer micelles to cosmetics. Any adverse symptoms were not observed.

• Clean Technology
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• v.27 no.3
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• pp.223-231
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• 2021

In order to address many issues associated with large volume changes of silicon, which has very low electrical conductivity but offers about 10 times higher theoretical capacity than graphite (Gr), a silicon nanoparticles/hollow carbon (SiNP/HC) composite having bimodal-mesopores was prepared using silica nanoparticles as a template. A control SiNP/C composite without a hollow structure was also prepared for comparison. The physico-chemical and electrochemical properties of SiNP/HC were analyzed by X-ray diffractometry, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption measurements for surface area and pore size distribution, scanning electron microscopy, transmission electron microscopy, galvanostatic cycling, and cyclic voltammetry tests to compare them with those of the SiNP/C composite. The SiNP/HC composite showed significantly better cycle life and efficiency than the SiNP/C, with minimal increase in electrode thickness after long cycles. A hybrid composite, SiNP/HC@Gr, prepared by physical mixing of the SiNP/HC and Gr at a 50:50 weight ratio, exhibited even better cycle life and efficiency than the SiNP/HC at low capacity. Thus, silicon/carbon composites designed to have hollow spaces capable of accommodating volume expansion were found to be highly effective for long cycle life of silicon-based composites. However, further study is required to improve the low initial coulombic efficiency of SiNP/HC and SiNP/HC@Gr, which is possibly because of their high surface area causing excessive electrolyte decomposition for the formation of solid-electrolyte-interface layers.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.656-662
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• 2013

The iron oxide ($Fe_3O_4$) particles in the coolant of the secondary system of a nuclear power plant reduce the heat transfer performance or induce corrosion on the surface of the heat transfer tube. To prevent these problems, we conducted a study to improve the dispersion stability of iron oxide using polymeric dispersant injection in simulated secondary system water. The three kinds of anionic polymers containing carboxyl groups were selected. The dispersion characteristics of the iron oxide particles with the polymeric dispersants were evaluated by performing a settling test and measuring the transmission, the zeta potential, and the hydrodynamic particle size of the colloid solutions. Polymeric dispersants had a significant impact on the iron oxide dispersion stability in an aqueous solution. While the dispersant injection tended to improve the dispersion stability, the dispersion stability of iron oxide did not increase linearly with an increase in the dispersant concentration. This non-linearity is due to the agglomerations between the iron oxide particles above a critical dispersant concentration. The effect of the dispersant on the dispersion stability improvement was significant when the dispersant concentration ratio (ppm, dispersant/magnetite) was in the range of 0.1 to 0.01. This suggests that the optimization of dispersant concentration is required to maximize the iron oxide removal effect with the dispersant injection considering the applied environments, the iron oxide concentration and the concentration ratio of dispersant to iron oxide.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.329-337
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• 2010

Purpose: The surfaces and compositions of rigid gas permeable (RGP) contact lenses were analyzed with the consistent methods, and the basic informations for the composition design of lens materials were suggested. Methods: The bulk structures were analyzed by using Fourier infrared spectroscopy (FTIR), the compositions of surface components were observed by using x-ray photoelectron spectroscopy (XPS), the surface morphology and roughness were observed using atomic force microscopy (AFM), and the wettabilities were estimated by the surface wetting angles. The relations and trends of those results were analyzed. Results: The high oxygen permeability RGP lenses showed the trend that the fluorine decreases and the silicon increases. As the silicon and fluorine contents increased, the carbon and oxygen contents of RGP lens materials decreased at a constant ratio. The decreasing ratio of the carbon contents was three times larger than the decreasing ratio of oxygen contents. The composition of the surface treated lens was far from these tendency line. When the silicon contents increased, the rough surface was formed with the cohered particles. When the fluorine contents increased, the rough surface was formed with the deep flaws. The surface roughness increased and then wettabilities decreased as the silicon and fluorine contents increased. For the surface roughness changes, the increasing ratio of the silicon contents was two times larger than the increasing ratio of fluorine contents. The surface of RGP lens materials appeared the hydrophobic character of which the wettabilities decreased when the roughnesses increased. Conclusions: The surfaces and compositions of RGP contact lenses were measured by the same methods. Those results and relationships were compared and analysed. It is considered that these research results will be applied with the basic data for the composition design of lens materials.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.3
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• pp.247-256
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• 2011

Existing organic UV protection materials seem to be problematic due to their penetration and irritation to skin. Inorganic UV protection materials are also at issue for safety of their nano-type transformation. Therefore, the recent studies of UV protection materials have been focused not only on the effectiveness but also on their safety. One of the UV protection materials in study which have higher safety is the organic-inorganic conjugation type UV protection material. Previously, we have reported the manufacturing process, physical property and UV protection efficiency of methoxychinnamidoprophy poloysilsesquixan as a new cross-linked polymer type UV protection material. In this study, we have evaluated the effect of the methoxychinnamidoprophy poloysilsesquixan on embryo-fetal development in SD rats. This study is expected to show some definite information related to the effect on pregnancy or embryo-fetal abnormality in case of the clinical exposure of the methoxychinnamidoprophy poloysilsesquixan.

• Membrane Journal
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• v.34 no.1
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• pp.38-49
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• 2024

Wastewater treatment using membrane bioreactors has been extensively used to alleviate water shortage and pollution by improving the quality of the treated water discharged into the environment. However, membrane biofouling persistently holds back an MBR process by reducing the process efficiency. Herein, we synthesized carbon nanospheres (CNSs) with many hydrophilic oxygen groups and utilized them as an additive to prepare high-performance ultrafiltration (UF) membranes with hydrophilicity and porous pore structure. CNSs were found to form crescent-shaped pores on the membrane surface, increasing the mean surface pore size by about 40% without causing significant defects larger than bubble points, as the CNS content increased by 4.6 wt%. In addition, the porous pore structure of CNS composite membranes was also attributable to the CNS's isotropic morphologies and relatively low particle number density because the aforementioned properties contributed to preventing the polymer solution viscosity from soaring with the loading of CNS. However, too porous structure compromised the mechanical properties, such that CNS2.3 was the best from a comprehensive consideration including the pore structure and mechanical properties. As a result, CNS2.3 showed not only 2 times higher water permeability than CNS0 but also 5 times longer operation duration until membrane cleaning was required.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.4
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• pp.311-318
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• 2010

U. S. NRC Regulation Guide 1.52 regulating ESF ACS in nuclear power plants has been revised to revision 3. To apply reduction of operability test time, allowance of alternative challenge agents for in-place leak test of HEPA filters, and upgrade of Methyl Iodide penetration acceptance criterion in activated carbon performance test suggested in Reg. Guide 1.52(Rev.3) on Yonggwang units 5 and 6 ESF ACSes, technical feasibility study was carried out with on-site experiments as well as experiments with a lab-scale model. It was confirmed that the moisture in the system returned to the level before the test in 1 or 4 days even though the moisture was removed during the operability test lasting more than 10 hours. Therefore, it is appropriate to perform monthly operability test in 15 minutes just long enough to check the operability of equipment. To change challenge material for in-place HEPA filter leak test, size of aerosol, production rate, and leak detection capability were compared for DOP and PAO. It was concluded that PAO can be substituted for DOP in nuclear power plants. The upgrade of Methyl Iodide penetration acceptance criterion from 0.175 % to 0.5 % in active carbon filter bed deeper than 4 inches was to conform to the change of activated carbon performance test method to ASTM D3803(1989). It was confirmed that Methyl Iodide penetration acceptance criterion of 0.5 % under $30^{\circ}C$, relative humidity 95 % condition was conservatively good enough for testing performance of active carbon insitu. The licence change of Yonggwang units 5 and 6 has been completed based on this study.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.123-129
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• 1993

Physico-chemical properties of the acetylated and raw starch were Investigated with the chucheongbyeo and samkangbyeo. The solubility and swelling power was increased by acylation reaction. The light transmittance was higher in the acetylated rice starch. The blue value of chucheongbyeo and samkangbyeo rice starches were lowered to 10.9% and 16.0%, respectively, by the acylation reaction. The alkali number was 7.6 in the chucheongbyeo rice starch and 7.2 in the samkangbyeo rice starch, whereas acylated starch in the same orders was 55 and 52, respectively. The hardness, adhesion, cohesion of starch gel was increased by the acylation reaction. The temperature of initial gelatinization of the acetylated chucheongbyeo and samkangbyeo rice starch was shown to $59^{\circ}C\;and\;62^{\circ}C$, respectively, lowering $5{\sim}6^{\circ}C$ in temperature by the acylation. The viscosity as well as by the acylation reaction was raised 38% and 14%, respectively. The rice starch particles were shown to plygonal structure. But it were deformed in the acylated starch, and was completely destroyed in the starch which is by gelatinized for 30 min. at $70^{\circ}C$.

• Journal of fish pathology
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• v.11 no.2
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• pp.129-136
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• 1998

In March 1997, a new rhabdovirus was isolated from moribund cultured Japanese flounder Paralichthys olivaceus in sea water tank and cage culture systems in Kyung-Nam and Chun-Nam province, Korea. At temperature $15^{\circ}C$ the virus replicated and induced cytopathic effects (CPE), which progressed to eventual cytolysis, in susceptible cell lines, including RTG-2 and EPC. The CHES-214 cell line was refractory. Virus particles were bullet-shaped and measured $70nm{\times}100$ to 150 nm in size. The isolate was sensitive to pH 3, to diethyl ether, and to heat ($50^{\circ}C$ 5 min, $60^{\circ}C$ 1 min). Viral replication was not inhibited by $10^{-4}$ M 5-iododeoxyuridine. Virus infectivity was reduced by anti-HRV (8401-H) rabbit serum, but can not reduced by antisera against infectious hematopoietic necrosis virus (IHNV), chum salmon reovirus (CSV), retrovirus of salmonid (RVS) and infectious pancreatic necrosis virus (IPNV). HRV virus antigen was detected by fluorescent antibody test (FAT) in the cytoplasm of infected EPC cell. Purified isolates virions were composed of: polymerase (L), glycoprotein (G), nucleoprotein (N) and 2 matrix proteins (M1 and M2). Based upon their relative mobilities, the estimated molecular weights of the proteins were: L, 160 kDa; G, 55 kDa; N, 45 kDa; M1, 26 kDa; and M2, 22 kDa.