• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.7
• /
• pp.1048-1054
• /
• 2014

The purpose of this study was carried out to investigate the cause of sulfur dioxide occurrence, general element composition, sulfur compounds, heavy metals, macro- & micro-minerals, and oxidation-reduction potential (ORP) following baking time course of RS (RS1, RS2, RS3, and RS4) and mudflat solar salts (MSS). Sulfur dioxide ($SO_2$) and sulfite ($SO{_3}^{2-}$) were not detected in MSS or RS. However, sulfate ($SO{_4}^{2-}$) content significantly decreased in RS (29,878.15~36,097.45 ppm) compared to that in MSS (35,601.65 ppm). ORP was 181.15 mV in MSS, and 58.55 mV in RS1. Moisture content was 9.34% in MSS and 0.00% in RS with increased NaCl (94.77~95.77%). Moisture and NaCl contents showed no significant difference in RS. Insoluble and sandy residues were higher in RS than in MSS, whereas Ca and K showed no significant difference. Mg and Cl contents were higher in RS than in MSS. Br level was higher in MSS (628.1 ppm) than in RS (512.72~586.62 ppm), but there was no significant difference in $NO_3$. Heavy metals (Pb, As, and Hg) were more abundant in RS than in MSS, but levels were still safe. These results suggest that MSS and RS may increase protection against from $SO_2$ and $SO{_3}^{2-}$.

• Geotechnical Engineering
• /
• v.10 no.2
• /
• pp.121-140
• /
• 1994

This paper presents the probabilistic model to evaluate the three-dimensional stability of layered deposits and c-0 soil slopes. Rotational slides are assumed with a cylindroid control part terminated with plane ends. And the potential failure surfaces in this study are assumed with the logarithmic spiral curve refracted at boundary of layers. This model takes into consideration the spatial variabilities of soil properties and the uncertainties stemming from insufficient number of samples and the discrepancies between laboratory measured and in -situ values of shear strength parameters. From the probabilistic approxi mate method (FOSM and SOSM method), the mean and variance of safety factor are calculated, respectively. And the programs based on above models is developed and a case study is analysed in detail to study the sensitivity of results to variations in different parameters by using the programs developed in this study. On the basis of thin study the following conclusions could be stated : (1) The sensitivity analysis shown that the probability of failure is more sensitive to the uncertainty of the angle of internal friction than that of the cohesion, (2) The total 3-D proability of failure and the critical width of failure are significantly affected by total width of slope. It is found that the total 3-D probability of failure and the critical width of failure increase with increasing the slope width when seismic forces do not exist and the total 3-D probability of failure increases with increasing the slope width and the critical width of failure decreases when seismic intensity is relatively large, (3) A decrease in the safety factor (due to effect such as a rise in the mean ground water level, lower shear strength parameters, lower values for the correction factors, etc.) would result in reduction in the critical width of failure.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.13 no.1 s.28
• /
• pp.93-102
• /
• 2007

Particle materials sink in bottom and dissolved inorganic substances release from sediment and many kinds of materials continuously exchange in sediment and water column as well as transfer and transformation in sediment. The study of sediment quality means the state of sediment pollution relation of the water quality, sediment biota, materials fluxes between sediment and water column, transformation of materials in sediment is being important in recent. The state of sediment quality imply that the history of water pollution for long time, because the sediment quality does not change temporally. The sediment quality of bottom water can be used as a good indicator of pollution at present and in future. The major index of sediment qualities are the content of nutrients and hazard materials such as metals, Ignition Loss (IL), Total Sulfur (TS), Oxidation Reduction Potential (ORP), sediment COD, color, odor and the release of nutrients from sediment. However, there are some arguments between researchers about compare to estimation of sediment quality and sampling and analysis of sediment. In this study, I will introduce the method of sediment sampling, analyzing and estimating of the sediment pollution.

• Journal of the Korean Magnetics Society
• /
• v.5 no.1
• /
• pp.8-14
• /
• 1995

The magnetic properties of an $Fe_{87}Zr_{7}B_{5}Ag_{1}$(at.%) amorphous alloy have been investigated as a function of annealing temperatures to clarify its application potential as a core material for high-frequency use by adding a small amount of insoluble element of Ag. A new excellent soft magnetic material was developed. The amorphous alloy produced by relatively low temperature annealing at $T_{a}=400^{\circ}C$ exhibited very high initial permeability$(\mu_{i})$ of 288,000 at 1kHz and 2mOe, very low coercivity$(H_{c})$ of 15mOe and low core loss$(W_{c})$ of 50W/kg at 100kHz and 1,000G which is comparable with Co-based amorphous alloys, respectively. It is notable that the values obtained in the present study are the best magnetic properties among various kinds of Fe-based soft amorphous materials reported up to date. The reasons for the achievement of good soft magnetic properties are presumably due to the homogeneous formation of very fine $\alpha$-Fe clusters with the size of 2~3nm in an amorphous matrix, which can be deduced from the increase of resistivity and the TEM observation. The very fine $\alpha$-Fe clusters embedded in an amorphous matrix had a great influence on reduction of magnetostriction and refinement of magnetic domain.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.18 no.2
• /
• pp.67-83
• /
• 2012

In order to evaluate die geochemical characteristics of sediment in a semi-enclosed bay used as shellfish and fish farming area, the concentrations of metallic(V, Cr, Mn, Fe, Co. Ni, Cu, Zn, Ag, Cd, Hg, Ph, As) and non-metallic(P, Se) elements and uranium were measured in the surface sediment samples collected from 19 stations of Gamak Bay in April 2010. Metal contamination status in the sediments were also evaluated using the sediment quality guidelines(SQGs) proposed by the National Oceanic and Atmospheric Administration(NOAA) and the enrichment factor(EF). The concentrations of elements in sediment were mainly controlled by quartz-dilution effect(V, Cr, Fe, Co and Ni), the dilution effect of organic matter(Cd and U), and metal redistribution by the decomposition of organic matter(Mn, Ag, As, and Se). The concentrations of metals, except As and Ni, in sediments from all sampling stations were lower than ERL values of NOAA. Conclusively, the surface sediment of Gamak Bay was slightly polluted with Ni, Ag, Cd, and Cd but was not polluted with other elements on the basis of EF results. Our results suggest that the surface sediment in Gamak Bay is not polluted by metallic elements.

• Journal of the Society of Naval Architects of Korea
• /
• v.33 no.3
• /
• pp.35-47
• /
• 1996

A surface panel method treating a boundary-value problem of the Dirichlet type is presented to design a three dimensional body with free surface corresponding to a prescribed pressure distribution. An integral equation is derived from Green's theorem, giving a relation between total potential of known strength and the unknown local flux. Upon discretization, a system of linear simultaneous equations is formed including free surface boundary condition and is solved for an assumed geometry. The pseudo local flux, present due to the incorrect positioning of the assumed geometry, plays a role f the geometry corrector, with which the new geometry is computed for the next iteration. Sample designs for submerged spheroids and Wigley hull and carried out to demonstrate the stable convergence, the effectiveness and the robustness of the method. For the calculation of the wave resistance, normal dipoles and Rankine sources are distributed on the body surface and Rankine sources on the free surface. The free surface boundary condition is linearized with respect to the oncoming flow. Four-points upwind finite difference scheme is used to compute the free surface boundary condition. A hyperboloidal panel is adopted to represent the hull surface, which can compensate the defects of the low-order panel method. The design of a 5500TEU container carrier is performed with respect to reduction of the wave resistance. To reduce the wave resistance, calculated pressure on the hull surface is modified to have the lower fluctuation, and is applied as a Dirichlet type dynamic boundary condition on the hull surface. The designed hull form is verified to have the lower wave resistance than the initial one not only by computation but by experiment.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.31 no.3 s.52
• /
• pp.245-251
• /
• 2005

Safety is one of the key issue in the regulation of cosmetics. Cosmetic Act deals with it in Korea. The guidance for the testing cosmetic ingredients and their safety evaluation are prepared by Korea Food and Drug Administration. Ultraviolet radiation could Induce skin damage, edema, erythema, photoaging, immune dysfunction and skin cancer. Ultraviolet radiation is classified as Group 2A(probably carcinogenic to humans) by International Agenry for Reaserch on Cancer(IARC). The in vitro methodologies for evaluating the toxic potential of ingredients reported in the literature have not yet been sufficiently validated for use in areas other than the study for mutagenicity/genotoxicity, for pre-screening for severe irritancy, for screening of phototoxicity and for evaluating the percutaneous absorption. The 3T3 neutral red uptake photoxicity test (3T3 NRU PT) was accepted as OECD toxicity guideline in 2002. The 3T3 NRU PT is an in vitro method based on a comparison of the cytotoxicitv of a chemical when tested in the presence and in the absence of exposure to a non-cytotoxic dose of UVA/visible light.

• Geophysics and Geophysical Exploration
• /
• v.16 no.1
• /
• pp.36-44
• /
• 2013

We conducted the airborne magnetic and radiometric survey for the characterization of the black shale related and pyrometamorphic uranium deposits distributed in Geumsan area. For the successful characterization of the uranium deposits, the general geological and structural geological features were investigated based on the lithological and linear feature analysis to individual magnetic and radiometric data as the first step. Lithological analysis from the magnetic reduction to the pole and downward continuation map revealed that prominent positive anomalies caused by black and dark gray slate member were clearly recognized as magnetic sources. These results indicate that magnetic survey, even though it is not a direct method for the detection of uranium, can be a useful tool in uranium detection. By the linear feature analysis based on 2nd vertical derivative and curvature map, two linearments corresponded the gray hornfels and black slate member were extracted and in succession, the additional uranium potential zone was inferred. Final discrimination whether uranium-rich or not was confirmed by radiometric and uranium anomaly map. From these analysis, we finally concluded that uranium deposit originated by pyrometamorphic process was confined near the intrusive area only. On the contrary, it was found that black shale related uranium deposit is distributed and extended through out the entire survey area with south-west to north-east direction. In addition, from the linear feature analysis based on radiometric total anomaly map, the typical discontinuous characteristics were recognized in areas where uranium-contained linearments cross the faults. From the above discussion, we concluded that airborne magnetic and radiometric survey are complementary to each other. So it is preferable to carry out simultaneously for the efficient data processing and fruitful interpretation.

• Food Science and Preservation
• /
• v.20 no.5
• /
• pp.684-690
• /
• 2013

The antioxidant and photoprotective effects of various extracts from the roots of Rumex crispus L. were evaluated. The concentrations ($IC_{50}$) of various extracts required to exert a 50% reducing effect on a DPPH radical were found to be 0.005~0.093 mg/mL. The ethyl acetate extract showed a more remarkable effect than the positive control ascorbic acid. The concentrations ($QC_{50}$) of the butanol and ethyl acetate extracts required to exert a 50% reducing effect on the singlet oxygen $^1O_2$ were found to be 0.464 and 0.365 mg/mL, respectively. Both extracts were also found to protect the in vitro biological system from the detrimental effect of a singlet oxygen $^1O_2$ on type II photosensitization in E. coli and genomic DNA. Among all the tested extracts, the ethyl acetate and butanol extracts contained higher amounts of total phenolic contents. The results suggest that our study may contribute to the development of new bioactive products with potential applications to the reduction of photo-produced oxidative stress involving reactive oxygen species in living organisms.

• Food Science and Preservation
• /
• v.24 no.2
• /
• pp.221-229
• /
• 2017

The effect of sweet potato on the quality of Doenjang was investigated during fermentation. Viable cells of yeast decreased gradually after 4 weeks of fermentation, but those of aerobic bacteria increased in the late stage. Amylase activity of Doenjang was higher in the late stage of fermentation, while neutral protease maintained high activity during fermentation. Hunter L and b values of Doenjang decreased gradually during fermentation, while a value was increased. The pH of Doenjang decreased gradually until 10 weeks of fermentation, and the titratable acidity was low in the sweet potato added groups. The acid value was low in the Shinyulmi sweet potato added Doenjang. Water activity and oxidation-reduction potential of Doenjang decreased during fermentation. Reducing sugar of Doenjang decreased in the middle stage of fermentation, and it was low in sweet potato added groups. The alcohol content of Doenjang decreased after 2 weeks of fermentation. Amino and ammonia-type nitrogen of Doenjang increased during fermentation and reached the maximum after 10 and 12 weeks of fermentation, respectively. After 12 weeks fermentation, 8% of Shinyulmi sweet potato added Doenjang was more favorable taste, flavor and overall acceptability (p<0.05) than the control or the Yeonwhangmi sweet potato added groups.