• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.162-162
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• 2007

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.323-327
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• 2008

본 연구는 판형 핀-관 열교환기의 열전달 특성을 상용 CFD 코드인 SC/Tetra를 사용하여 해석한 내용에 관한 것이다. 해석조건은 입구속도 0.63 m/s, 튜브온도 $44.5^{\circ}C$이다. 해석 열교환기는 총6가지로 검토하였으며 각각의 온도분포와 유동패턴을 해석하고 판형 핀-관 열교환기의 열전달 특성을 비교 검토하였다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2006.04a
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• pp.304-309
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• 2006

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.69-78
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• 2010

In order to investigate the degree of household dust contamination, 48 samples of household dust (24 from urban area and 24 from rural area) in Daegu city were collected in vacuum cleaner during January to February 2009. Samples were sieved below 100 ${\mu}m$, and 14 elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V, Zn) were analyzed using ICP after acid extraction. Results obtained from the source assessment of trace elements using enrichment factor showed that Ca, Fe, K, Mg, Mn, Na, and V were influenced by natural sources such as weathered rock and resuspended soil, while Cd, Cr, Cu, Ni, Pb and Zn were influenced by anthropogenic sources such as fuel combustion and waste incineration. Concentrations were remarkably higher in components from natural sources than in components from urban anthropogenic sources. Household dust in urban area was more affected by anthropogenic sources compared with that of rural area. Pollution index of heavy metals revealed that urban area was 1.8 times more contaminated with heavy metal components than rural area. The correlation analysis among trace elements indicated that components were correlated with natural sources-natural sources (Al-Mg, Al-Mn, Fe-Mn) and natural sources-anthropogenic sources (Al-V, Fe-Cr, V-Mn) in both urban area and rural area. Trace element components of rural area were more correlated than those of urban area. Houses that use oil for heating fuel had relatively higher contents of heavy metals rather than those using gas or electricity for heating fuel. Houses with children also had higher contents of heavy metals. In addition, the age of houses was found to influence the heavy metal levels in household dusts, with older houses (>10years) having higher concentrations than newer houses (<10years) and houses located near the major road (<10 m) were found to have relatively higher heavy metal levels in household dust.

• KDI Journal of Economic Policy
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• v.32 no.4
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• pp.1-34
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• 2010

We conduct a comprehensive risk analysis of household debt in Korea for the first time using the whole sample credit bureau (CB) data of 2.2 million individual debtors. After analysing debt service capacity profiles of debtor groups classified by the borrower characteristics such as income, age, occupation, credit scoring, and the type of creditor business companies, we investigate the impact of interest rate and income changes on debt service-to-income ratios (DTIs) and default rates of respective debtor groups. Empirical results indicate that debt service burdens are relatively high for low income wage earners, high income self-employed, low income capital and card loan holders, and high income mutual savings loan holders. We also find that debtors from multiple financial companies are particularly weak in their debt service capacity. The scenario analysis indicates that financial companies, with the current level of capital buffers, may be able to absorb negative consequences arising from the increase in DTIs and loan default rates if the interest rate and income changes remain modest. However, the negative consequences may fall disproportionately on non-bank financial companies such as capital, credit card, and mutual savings banks, whose debtors' DTIs are already high. We also find that the refinancing risk of household debt is relatively high in Korea as more than half of household mortgage debts are bullet loans. As the DTIs of mortgage loan holders are already high, under the current DTI regulation, mortgage loans may not be readily refinanced especially when the interest rate rises. Disruptions in mortgage loan refinancing may put downward pressure on housing prices, which may in turn magnify refinancing risk under the current loan-to-value (LTV) regulation. Overall our analysis suggests that, for more effective monitoring of household debt risk, it is necessary to combine existing surveillance schemes based on macro aggregate indicators with more comprehensive and detailed risk analyses based on micro individual data.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.103-109
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• 2016

Efficacy of cosmetics has been mainly evaluated by qualitative and quantitative methods based on visual sense, tactile sense and skin structure until now. In this study, we suggested a novel evaluation method for skin status based on sound; measuring and analyzing the rubbing noise generated by applying cosmetics. First, the rubbing noise was measured at a close range by a high-sensitivity microphone in anechoic environment, and the noises were analyzed by 1/3 octave band analysis in frequency-domain. Three conditions, 1) before washing, 2) after washing and 3) after application of cosmetics, were compared. As a result, sound pressure level (SPL) of rubbing noise after washing was larger than that of before washing, and the SPL of rubbing noise after cosmetic application was the smallest. Furthermore, the energy of rubbing noise after application was higher than that of the before and after washing conditions in a low frequency band (lower than 2 kHz region). Conversely, the energy of rubbing noise after application was much lower than the others in a high-frequency band (upper than 2 kHz region). This change of energy distribution was described as a balloon-skin model. High SPL in the low frequency region after the cosmetic applications was due to the increase of "flexibility index", while SPL in the high frequency region significantly decreased because of the attenuation which is related to "softness index". Therefore, we developed two indices based on the spectrum-energy difference for evaluating skin conditions. This proposed method and indices were verified via skin flexibility and roughness measurement using cutometer and primos respectively. These results suggest that acoustic measurement of skin friction noise may be a new skin status evaluation method.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.4
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• pp.271-276
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• 2012

In this study, the dispersion ability of powder in low viscosity solubilization system that depends on variety and amount of additives and powders was investigated. A PMMA powder shows outstanding dispersion ability because of its repulsive force of partially charged chain and low density of porous structure. A sample, which contains salts, showed better dispersion tendency than a sample without any additives. The dispersion ability was quantity of salts dependent. Furthermore, a sample with divalent ion salts, like $MgSO_4$, showed better dispersion tendency than that of monovalent ion salts, like NaCl or KCl. The reason for the better dispersion tendency was due to the existence of ionized salts around the powders which significantly improves repulsive force between powders and consequently reduces powder aggregation. The sample with chelating agent, like EDTA as an additive, had improved dispersion ability. EDTA chelates and blocks metal cation therefore anion's character is maximized and repulsive force between powders is improved. As a result, salts and EDTA help to improve the powder dispersion ability and the stability of product.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.3
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• pp.219-228
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• 2009

This study was performed to evaluate a deodorant body wash with 1.0 wt% of triclosan and 0.4 wt% of bamboo salt, which have an inhibitory effect on axillary malodor. In this studies, in vitro antibacterial study and the clinical study, which was designed by randomized assignment, double-blind and cross-over, were performed. In the antibacterial study, test sample, which was body wash having 1.0 wt% of triclosan and 0.4 wt% of bamboo salt, have a potent antibacterial effect on Corynebacterium glutamicum, Corynebacterium xerosis, Corynebacterium jeikeium. In the clinical study, test sample has a potent and significant deodorizing effect on axillary malodor and an antibacterial efficacy. And its efficacy was maintained for 9 h at least. There was no side effect during the period of clinical study. Consequently, body wash, containing 1.0 wt% of triclosan and 0.4 wt% of bamboo salt, has the effectiveness and the safety about axillary malodor reduction.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.274-284
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• 2008

For forest valuation, various input data were generally required: for example, slope, timber stocks, logging costs, hauling costs, market values of timber, afforestation costs, thinning costs, and so on. To enhance the efficiency of forest valuation process, it would be helpful to guide how and where to acquire such data sets. Moreover, to make an appraisal of timber assets through the Forestry Household Economy Survey, it would be inevitable to use standardized input data by region or tree species. Therefore, this research intended to develop a methodology of standardizing each input data, and to present its available data sources. Also, a guidance was presented to explain how to control input data within the appraisal process. Then, the appraisal process were analyzed and summarized in four types of information such as system flowchart, process flowcharts, detail flowcharts, and skimmer data, which are essential elements in developing an appraisal software, named EnVAST (Engine of Valuation System for Timber Assets). The software was designed to generate 'the standard forest valuation table' by species and province as the final output that is applicable for the forest valuation through the Forestry Household Economy Survey in Korea.

• Journal of Korean Society of Forest Science
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• v.97 no.1
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• pp.77-82
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• 2008

For the last few decades, forest resources in Korea have continuously increased in terms of their stocks. However, due to the low profitability of timber harvesting in Korea, their economic values have not been well recognized. Furthermore, their economic values have not been counted in national statistics associated with forest resources such as the Forestry Household Economy Survey or the National Accounting. This research fundamentally aimed at building a forest valuation system or a procedure that enables one to evaluate the national-level economic values of timber assets in Korea. For this research, it is necessarily required to understand the principles of appraisal methods and any issues raised in their practical applications. Thus, a comprehensive review of appraisal methods utilized in Korea and other countries was conducted in this research. Also, the current valuation system of the National Forests in Korea was investigated. Through the review and the investigation, it was found that an alternative consists of two appraisal methods, the 'Capitalized Income Value' method adopting the Internal Rate of Return (IRR) for the below-rotation age forest and the 'Derived Residual Value' method for the above-rotation age forest, could be the most acceptable for evaluating timber assets of forestry households derived from the Forestry Household Economy Survey in Korea.