• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.491-495
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• 2005

Vanadium pentoxide xerogels with a doping ratio of $Al/V_2O_5$ ranging from 0.01 to 0.05 were synthesized by doping Al into $V_2O_5$ xerogel via the sol-gel process. By using the synthesized $Al_xV_2O_5$, the $Li/Al_xV_2O_5$ cells were assembled to investigate the chemical and electrochemical properties. Surface morphology of the $Al_xV_2O_5$ xerogel showed an anisotropic corrugated sheet-like matrix, and the interlayer distance was about $11.5{\AA}$. The IR spectra of the $Al_xV_2O_5$ revealed that the doped Al was coordinated to the vanadyl group in $V_2O_5$. The $Al_xV_2O_5$ xerogels showed enhanced reversibility and energy density compared with the $V_2O_5$ xerogel. The specific capacity of the $Al_{0.05}V_2O_5$ xerogel was more than 200 mAh/g at 10 mA/g discharge rate, and cycle efficiency was about 90% after the 31st cycling test between 1.9 V and 3.9 V.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1132-1141
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• 1996

Heterogeneous cation exchange membrane(HCEM) was prepared with LLDPE(Linear Low Density Poly-ethylene) as binder, powdered cation exchange resins($diameter{\leq}149{\mu}m$) as ion-exchange material and glycerol as additive for electrodialysis and electrodeionization system. The weight ratio of (binder/ion exchange)/glycerol was (60%/40%)/5%, (55%/45%)/5%, (50%/50%)/5% and (40%/60%)/5%. The characterization of prepared HCEM was evaluated on mechanical, electrochemical, morphology and ion permeable properties. It was compared with commercial membrane. Electrochemical properties of HCEM of (50%/50% )/5% were very similar to value of IONPURE(commercial membrane), in which ion exchange capacity, ion transfer number and membrane resistance were to be 1.733meq/g, 0.96 and $16.08{\Omega}/cm^2$, respectively. Ion permeability of the membrane was better than that of IONPURE membrane. Compared with IONPURE membrane, the HCEM had a higher tensile strength and lower elongation and modulus, in which HCEM had tensile strength of $62.33kg/cm^2$, elongation of 87.42% and modulus of $658.53kg/cm^2$. The HCEM of (50%/50% )15% was optimum combination.

• Journal of Radiation Protection and Research
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• v.23 no.3
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• pp.159-174
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• 1998

Personal dosimetry system is required to measure the personal dose equivalent accurately in a wide range of radiation fields, but the dose evaluation algorithms have been developed with the X-ray fields described in MOST Ordinance (equivalent to the ANSI N13.11) from which the actual fields to be monitored may be significantly different. To evaluate the dose more accurately when workers are exposed to the non-ANSI N13.11 radiation fields, two algorithms for monochromatic radiations (one algorithm was used for various ratios of TL dosimeter and the other for matrix approximation) were developed with the experimental data of the energy responses of the $CaSO_4:Dy$ TL materials irradiated by monochromatic X-ray fields recently established in KAERI, and compared with the another algorithm developed on the basis of the ANSI N13.11 continuous spectrum X-ray fields. Then it follows the discussions for some results of the algorithm testing including mixed fields irradiations and angular response conducted in IAEA/RCA intercomparison as well as ANSI and ISO continuous spectrum X-ray and monochromatic radiation fields. The developed algorithms were successfully performed the test not only in the continuous spectrum X-ray fields given by MOST Ordinance but also in the several non-MOST Ordinance radiation fields which could be encountered in the practical working environments.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.163-176
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• 2006

The concept of 'spatial association' explains spatial distribution pattern of geographical phenomenon based on similarity with neighborhoods, as in the Tobler's Law of Geography: 'Everything is related to everything else, but near things are more related than distant things.' In this study, we develop a time-series exploratory analysis tool for discovering temporal patterns of spatial association by combining spatial statistics and geo-visualization, and thus present a possibility to support spatial decision-making process. As for the spatial proximity weight matrix indispensable to measuring global and local spatial association, we employ a variety of flexible weighting schemes using geometric characteristics of areal unit. In addition, we renovate the existing visualization methods for more effective understanding of the procedures and results of time-series analysis on spatial association: for instance, temporal parallel coordinate plot with box plot, animated map for spatial association, and 3D Moran scatterplot. The feasibility of our system is verified by time-series analysis experiments on the spatial association of land price fluctuation rate for all administrative units in Korea, $1995{\sim}2004$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.56-65
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• 2005

A dynamic analysis method that freezes a time domain by discretization and solves the spatial propagation equation has a unique feature that provides a degree of freedom on spatial domain compared with the space discretization or space-time discretization finite element method. Using this feature, the time finite element analysis can be effectively applied to optimize the spatial characteristics of distributed type actuators. In this research, the time domain finite element method was used to discretize the model. A state variable vector was used in the discretization to include arbitrary initial conditions. A performance index was proposed on spatial domain to consider both potential and vibrational energy, so that the resulting shape of the distributed actuator was optimized for dynamic control of the structure. It is assumed that the structure satisfies the final rest condition using the realizable control scheme although the initial disturbance can affect the system response. Both equations on states and costates were derived based on the selected performance index and structural model. Ricatti matrix differential equations on state and costate variables were derived by the reconfiguration of the sub-matrices and application of time/space boundary conditions, and finally optimal actuator distribution was obtained. Numerical simulation results validated the proposed actuator shape optimization scheme.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.2 s.57
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• pp.75-79
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• 2006

In this study. we evaluated anti-aging activity of medical plants that protect the skin cell damage induced by UV irradiation. We have investigated diverse biological activities of Selaginella tamariscina as an anti-aging ingredient of cosmetics. S. tamariscina was found to show scavenging activities of radicals and reactive oxygen species (ROS) with the $IC_{50}$ values of $65.1{\mu}g/mL$ against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and $40.9 {\mu}g/mL$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. For testing intracellular ROS scavenging activity, the cultured human dermal fibroblasts were analyzed by increase in dichlorofluorescein (DCF) fluorescence upon exposure to UVB $20 mJ/cm^2$ after treatment of S. tamariscina. UVA-induced MMP-1 protein and mRNA expression in human dermal fibroblasts were reduced in a dose-dependent manner by S. tamariscina. Moreover, S. tamariscina inhibited MMP-2 (gelatinase) activity in UVA-irradiated human dermal fibroblasts assayed by zymography and semi-quantitative RT-PCR. Taken together, these results suggest that S. tamariscina may act as an anti-aging agent by Increasing collagen and preventing the skin cell damage induced by UV irradiation, and imply that S. tamariscina nay be useful as a new ingredient for anti-aging cosmetics.

• The Journal of the Petrological Society of Korea
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• v.23 no.4
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• pp.311-324
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• 2014

The Hongjeom formation of the Pyeongan Supergroup in the Munkyeong coalfield mainly consists of metapsammite and metapelites. Metampelites occur as slate preserving chloritoid+chlorite+muscovite and andalusite+biotite+chlorite+muscovite mineral assemblages. Chloritoid and andalusite occur as porphyroblast, and the matrix composed of fine-grained micas. Metamorphic P-T conditions for these mineral assemblages are $510-520^{\circ}C$ and 3.0-3.5kbar based on P-T pseudosection in $MnO-K_2O-FeO-MgO-Al_2O_3-SiO_2-H_2O(MnKFMASH)$ system and isopleth intersections of Fe/(Fe+Mg) ratios in chloritoid and chlorite. The medium temperature and low pressure metamorphism resulted from a higher geothermal gradient ($40-45^{\circ}C/km$) condition than that of burial metamorphism. The youngest (SHRIMP U-Pb age; ca. 327-310 Ma) detrital zircon grains from the Hongjeom formation display oscillatory zoning and relatively high Th/U ratio (0.60-1.12). Based on the previous sedimentary, paleontological, and geochronological studies in the Taebaeksan basin together with results of this study, we suggest that (1) initial deposition of the Hongjeom formation was contemporaneous with a magmatic activity in the provenance, (2) the Pyeongan Supergroup was deposited in an arc-related basin at an active continental margin during the Carboniferous to Permain, and (3) magmatic activities occurred repetitively in relatively short interval in the active continental margin had continuously supplied sediments to the basin.

• Polymer(Korea)
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• v.32 no.1
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• pp.63-69
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• 2008

The mechanical properties and morphologies of cellulose blends with two different additives were compared. Poly (vinyl alcohol) (PVA) of ethylene glycol (EG) were used as additives in the formation of cellulose blends through the solution blending. The properties of blends were varied with the additive content in the polymer matrix. The ultimate tensile strength and initial modulus of the cellulose blends were highest for a blend PVA content of 30 wt% and for a blend EG content of 10 wt%, respectively. Ternary blended systems of composition of cellulose/PVA (70/30=w/w)/EG were also prepared by the solution blending method with different EG contents. The mechanical properties of these systems were found to be optimal for EG contents of up to 40 wt%. The mechanical properties of the cellulose ternary blend films were superior to those of the cellulose binary blend films. The oxygen permeability transmission rate ($O_2TR$) monotonically decreased with increasing EG content in the ternary blend films. Overall, the mechanical properties of the cellulose blend films were found to be better than those of pure cellulose films.

• The Korean Journal of Zoology
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• v.32 no.4
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• pp.429-440
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• 1989

Spirometru erinocei의 유충인 sparganum에서 추출한 조항원 단백질을 항원으로 하여 sparganosis, cysticercosis, hydatidosis환자의 IgG 항체와 정상인의 IgG 항체를 혈청반응시켜 ELISA와 EITB에 의해 교차반응을 일으키는 비 특이항원 성분과 종특이항원 성분을 추구하였다. 1. sparganum에서 0.01 M PBS (PH 7.4)로 추출한 조항원 단백질을 SDS-PAGE로 전개하여 290 Kd에서 23 Kd범위의 분자량을 가진 25개의 단백질이 분획되었다. 2. sparganum의 조항원을 항원으로하여 ELISA로 sparganosis, cysticercosis, hydatidosis 환자의 190 항체와의 혈청 반응치는 sparganosis환자에게서는 0.44 $\pm$ 0.07에서 1.90 $\pm$ 0.03으로 negative control normal sera의 0.D (0.15 $\pm$ 0.03)를 기준으로 하였을 때 모두 양성이며 민감도(sensitivity)가 100 %이었으며 cysticercosis, hydatidosis환자혈청에서 양성반응이 나타났으며 교차반응도 있었다. 3. EITB에서는 spargancsis환자의 IgG항체에 의해 16개의 항원성분이 인지되었으며 이 중 6개의 항원성분이 정상인의 혈청에서도 인지되어 교차반응을 일으키는 항원성분이었으며 cysticercosis환자혈청에서 인지된 4개의 항원성분 중 2개의 항원성분이 sparganosis 환자혈청에서 인지된 것과 같았으며 hydatidosis환자의 190항체에 의해 인지된 19개의 항원성분 중 12개의 항원성분이 sparganosis환자혈청에서 인지된 항원 성분과 같았다. 4. 290 Kd, 200 Kd, 28 Kd의 항원성분은 sparganosis환자의 196항체에서만 인지되었고 228 Kd, 152 Kd, 66 Kd항원성분은 hydatidosis환자의 19G항체에서만 인지되었으며 66 Kd항원성분은 sparganosis, cysticercosis, hydatidosis, 정상인의 혈청에서 모두 인지되었다. We studied the serological reaction between the specific and nonspecific antigenic components from metacestode (plerocercoid) of spiromeko erimacei and IgG antibodies in sparganosis, cysticercosis. hydatidosis patients and normal human sera by ELISA and EITB. We prepared the crude extracts of sparganlim from snake, Matrix tigrina laterolis and used as antigenic components. By SDS-PAGE, we detected a total 25 peptide bands (fractions) with 290 Kd to 23 Kd molecular weight, and 8 bands of these detected bands developed strongly by silver stain. In serological test, ELISA, we recognized the cross-reaction of antigenic components reacting with IgG antibodies in heterogenous sera, cysticercosis and hydatidosis patients sera. The crude antigenic components of sparganum showed the high sensitivity in sparganosis, hydatidosis patients sera, but showed lower sensitivity in cysticercosis patients sera than the sparasanosis, hydatidosis patients sera. Sixteen antigenic components of these 25 separated bands were recognized by antibodies In sparsanosis patients sera,8 antigenic components in normal human sera, 4 antigenic components in cysticercosis patients sera and 19 antigenic compoenents in hydatidosis patients sera. The crude antigenic compnenets with 290 Kd, 200 Kd, 125 Kd and 28 Kd molecular weight was only recognized in sparganosis patients sera, but 64 Kd antigenic component was nonspecific antigenic components which were also cross-reacted with sparganosis, hydatidosis, cysticercosis patients sera and normal human sera.

• Animal cells and systems
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• v.12 no.4
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• pp.313-319
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• 2008

The ultrastructure of oocytes during oogenesis and oocyte degeneration associated with follicle cells in female Sinonovacula constricta(Lamarck, 1818) were investigated by electron microscope observations. Ovarian follicles are surrounded by a matrix of vesicular connective tissue cells(VCT cells). VCT cells contain large quantities of glycogen particles and several lipid droplets in their cytoplasm. It is suggested that VCT cells act as a source of nutrients for vitellogenesis during oogenesis. In early vitellogenic oocytes, several coated vesicles, which appear at the basal region of the oocyte, lead to the formation of membrane-bound vesicles via endocytosis. The uptake of nutritive materials in coated vesicles formed by endocytosis appears through the formation of coated pits on the oolemma during vitellogenesis. During the late stage of oogenesis, yolk precursors(yolk granules), mitochondria and lipid droplets are present in the cytoplasm of late vitellogenic oocytes. In particular, proteinaceous yolk granules containing several different components are intermingles and form immature yolk granules. In the mature oocyte, small immature yolk granules are intermingled and form large mature yolk granules. Vitellogenesis occurs through a process of autosynthesis, involving combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum in the cytoplasm of vitellogenic oocytes. The process of heterosynthesis is where extraovarian precursors are incorporated into oocytes by endocytosis at the basal region of early vitellogenic oocytes before the formation of the vitelline coat. Follicle cells appear to play an important role in vitellogenesis and oocyte degeneration. The functions of attached follicle cells to the oocyte during oocyte degeneration are phagocytosis and digestion of phagosomes originating from oocyte degeneration. After digestion of phagosomes, it is assumed that the function of follicle cells can permit a transfer of yolk precursors necessary for vitellogenesis and allows for the accumulation of glycogen and lipid during oocyte degeneration, which can be employed by vitellogenic oocytes. Follicle cells of S. constricta may possess a lysosomal system for induction of oocyte breakdown and might resorb phagosomes in the cytoplasm for nutrient accumulation during oocyte degeneration.