• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6C
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• pp.305-314
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• 2012

This paper presents the quantitative damage assessment of granite taken from KAERI Underground Research Tunnel using acoustic emission (AE). The results determined showed the crack initiation and crack damage stress occurred at 48%, 72% of uniaxial compressive strength (UCS) and until the applied stress level was reached the crack damage stress, the damage degree was 0.06. When the applied stress exceeded 80%, 90% of UCS, the damage degree were 0.34, 0.06 and which were similar to those obtained from axial deformation modulus. The simply regression analysis was used to interpret the relationship of the two damage assessment techniques and the two were highly correlated ($R^2$=0.90). Therefore, damage degree based on the AE energy and mohr-coulomb failure criterion were adopted to predict the mechanical properties. As results, the axial deformation modulus, rock strength, internal friction angle, and cohesion of KURT rock were reduced 6%, 12%, 7%, and 3% until the applied stress was 70% of UCS. But when the applied stress reached 90% of UCS, the results were more reduced 69%, 72%, 62%, and 24%, respectively.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.131-143
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• 2013

Vibration condition monitoring of low-speed rotational slewing bearings is essential ever since it became necessary for a proper maintenance schedule that replaces the slewing bearings installed in massive machinery in the steel industry, among other applications. So far, acoustic emission(AE) is still the primary technique used for dealing with low-speed bearing cases. Few studies employed vibration analysis because the signal generated as a result of the impact between the rolling element and the natural defect spots at low rotational speeds is generally weak and sometimes buried in noise and other interference frequencies. In order to increase the impact energy, some researchers generate artificial defects with a predetermined length, width, and depth of crack on the inner or outer race surfaces. Consequently, the fault frequency of a particular fault is easy to identify. This paper presents the applications of empirical mode decomposition(EMD) and ensemble empirical mode decomposition(EEMD) for measuring vibration signals slewing bearings running at a low rotational speed of 15 rpm. The natural vibration damage data used in this paper are obtained from a Korean industrial company. In this study, EEMD is used to support and clarify the results of the fast Fourier transform(FFT) in identifying bearing fault frequencies.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.5
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• pp.443-451
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• 2013

Acoustic emission(AE) has emerged as a powerful nondestructive tool to detect any further growth or expansion of preexisting defects or to characterize failure mechanisms. Recently, this kind of technique, that is an in-situ monitoring of inside damages of materials or structures, becomes increasingly popular for monitoring the integrity of large structures like a huge wind turbine blade. In this study, the activities of AE signals generated from external artificial sources was evaluated and located by new developed signal mapping source location method and this test is conducted by 750 kW full-scale blade. And a new source location method was applied to assess the damage in the wind turbine blade during step-by-step static load test. In this static loading test, we have used a full scale blade of 100 kW in capacity. The results show that the acoustic emission activities give a good agreement with the stress distribution and damage location in the blade. Finally, the applicability of the new source location method was confirmed by comparison of the result of source location and experimental damage location.

• Journal of Nutrition and Health
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• v.52 no.5
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• pp.422-434
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• 2019

Purpose: The consumption of processed foods has recently been increasing due to changes in the living environment. The purpose of this study was to identify the contribution of processed food to the nutrient intake of adult Koreans. Methods: A total of 15,760 adult people in the $6^{th}$ National Health and Nutrition Examination Survey (2013 ~ 2015) were included in this study. According to the Korea Food and Drug Administration's classification criteria for processed foods, the 24 hour dietary recall data of the subjects were classified as processed food or natural food. The processed food intake, nutrient intake and major processed food sources by food groups were analyzed. Results: Men consumed more processed foods than did the women. Consumption of processed foods decreased with age, but it increased with the education level and the income level. The total daily processed food intake accounted for 68.1% of the total food intake. The food groups with high processed food intake were beverage, vegetables, cereals and grain products, fruits, and milk and dairy products in this order. The top food source of each food groups were beer, kimchi, bread, processed apple products, and milk. After adjusting for age, gender, and energy intake, all the nutrient intakes and percentage of dietary reference intakes for Koreans, except carbohydrates, were significantly higher in processed foods than in natural foods. The sodium intake from the processed food was 96.3% of total daily sodium intake. The intakes of nutrients from processed foods, excluding vitamins C, dietary fiber, iron, and vitamin A, were higher in men than in women. The intake of sodium from processed foods was highest for people of 30 ~ 49 years of age, and the intake of sodium from processed foods decreased for people over 50. Conclusion: Korean adults consumed more processed food than the natural food, consuming more calories and most of the nutrients from the processed food overall total daily intakes. The intake of processed foods is expected to further increase in the future, and nutritional education and research on the ingestion and selection of healthy processed foods are necessary.

• Journal of Climate Change Research
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• v.2 no.2
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• pp.93-106
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• 2011

Republic of Korea officially announced its mid term reduction target which reduce about 30% of BAU GHG emission by 2020 in the 15th meeting of UNFCCC(COP 15) held in Copenhagen, Denmark 2009. To achieve this goal, it is necessary to understand the serious of climate change and take part in GHG reduction not only industry but also the nation. However, such positive participation in green life which may cause inconvenient of the life of the people. It should be accomplished with providing reliable information. This study suggests the scientific potentialities of GHG emission by guideline on low carbon life and green life to form and change a lifestyle suitable for coping with climate change. And also, this study quantitate the GHG reduction which may reduce demand for air conditioning by cool biz and warm biz. In Korea, this campaign has become known as 'CoolMaebsi' by Ministry of Environmental of Korea. 'CoolMaebsi' is a compound word of 'Cool' which means feel refreshed, and 'Maebsi' is a Korean word which means attire. Though this campaign is effective and significant to reduce the GHG emission yet there were no study on quantitative analysis. Therefore this study calculated reduced energy consumption and potential GHG emission by measuring variation of skin temperature. As the result, wearing warm biz and cool biz have an effect of reducing not only the energy consumption but also GHG emission. To achieve the low carbon society, it is necessary to improve the energy saving system and introduce the policy which guide to change a life style.

• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.349-360
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• 2011

The international oil price have being fluctuated due to the exhaustion of fossil energy problem became big social issue. Rural villages are relatively sensitive to the energy problem, reflecting the characteristics of rural sustainable and stable introduction of renewable energy sources that are available is essential. In addition, through the influx of young workers in rural areas to regain vitality, efforts to improve rural living environment has been under the rural newtown project. In this study, a survey aimed at rural dwellers through the AHP, interview to report of realization about renewable energy and review the current policies. The results of realization survey though AHP are as follows, (1) the advantage of the natural environment (2) the superiority of government supporting policy and being economic, (3) easy to use, (4) ecologically stable, and (5) policy stable, respectively. In addition, renewable energy sources among the inhabitants of rural areas by solar energy was the highest score. The impact of regional characteristics compared with other energy sources receive little, easy to apply and has already been considerable technological development is considered.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1158-1166
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• 2013

SAR calculation method following the Mobi-Kids study protocol is analyzed and evaluation method of cumulative RF dose from mobile phones which have been used by a subject of case and control groups is proposed. An SAR database is built by calculating SAR distributions in 4 head models at different ages for representative phone models with the same conducted power. To obtain SAR distribution in a subject's head for a specific commercial phone which had/have been used by him/her, an SAR correction factor using SAR compliance test results is determined. Cumulative dose is calculated by considering mobile phone characteristics and use pattern such as call time and laterality(right and left).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.358-364
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• 2003

Gross energy intake fecal, nitrogen excretory and metabolized energy of snotted halibut juvenile, Eopsetta grigorjewi, fed on Tigriopus iaponicus (Group A) and the enriched Artemia nauplii (Group B), were quantitatively investigated and represented as balance equations of energy and material. Absorption efficiency (AE), gross conversion efficiency $(K_1)$ and net conversion efnciency $(K_2)$ were also estimated to understand the changes in efficiency by the prey Gross energy intake, fecal, nitrogen excretory, metabolized and growth energy of Group A were $2.790\pm0.247,\;0.495\pm0.046,\;0.018\pm0.003,\;0.214\pm0.047\;cal\;mg^{-1}\;day^{-1}$ and $2.063\;cal\;mg^{-1}\;day^{-1},$ respectively. The same parameters of Group B were $4.801\pm0.165,\;0.579\pm0.031,\;0.055\pm0.010,\;0.306\pm0.048\;cal\;mg^{-1}\;day^{-1}$ and $3.861\;cal\;mg^{-1}\;day^{-1},$ respectively. Energy budget of Group A and B were represented as 100 C= 7.67 M+17.7 F+0.65 U+73.94 G and 100C=6.37 M+ 12.1 F+1.15 U+80.42 G, respectively, where C, M, F, U, and G represent gross energy intake, metabolized energy, fecal energy, nitrogen excretory (non-fecal) energy and growth energy, respectively. AEs of Croup A and B were $81.52\pm1.89,\;86.79\pm0.70\%,$ respectively, with significant difference at p=0.01 level. However, $K_1\;and K_2$ of Group A and B showed no significant difference at p=0.01 level, with $74.21\pm6.57,\;80.48\pm2.76\%\;and\;91.17\pm7.26,\;92.74\pm2.69\%$ respectively. These results suggest that T. japonicus is a possible substitute for Artemia nauplii for the snotted halibut juvenile.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.177-184
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• 1998

The contact angle on powder hydrophobic polymer PMMA(polymethylmethacrylate), PVC(poly vinyl chloride) and hydrophilic metal aluminium was measured by wicking method on the base of Washburn equation for water, glycerol, formamide, diiodomethane, 1,1,2,2-tetrabromoethane, 1-bromonaphthalene, acetone, chloroform, benzene, ethanol, methanol, and for anionic surfactant SDS(sodium dodecyl sulfate) and cationic surfactant CATB(cetyl trimethylamonium bromide) aqueous solution with concentrations. The values of ${\gamma}_c$ estimated by Zisman plot and adhesion tension plot for contact angle with organic liquids, SDS, and CTAB aqueous solutions were 43.5, 28.3, and $36.2mNm^{-1}$ for PMMA and 44.2, 25.0, and $34.8mNm^{-1}$ for PVC, respectively. From the results, it was considered that wettability and characteristics of solid surface were transformed by adding surfactant. The surface free energy, ${\gamma}_s$ and its components of PMMA, PVC, and aluminium were determined using harmonic equation.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.559-565
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• 2000

This studies were to investigate the effects of low power Helium-Neon Infra-Red (He-Ne IR) laser on the healing of the peripheral neuropathy in diabetic rats. The twenty one Spraque-Dewley adult male rats were assigned to the 3 groups: the control group (7), the diabetic group (7) and the laser group (7). The diabetic group was induced with a single intravenous injection of 50mg/kg body weight streptozotocin dissolved to 0.01mol/L citrate buffer, pH 4.5. The experimental laser group was irradiated low power He-Ne IR laser for 5 minutes every day during 21 days to the diabetic group. The results were as follows: For on and two weeks with laser treatment, there were significantly increased the terminal latencies of the laser treatment group than those of diabetic group, but that was significantly decreased to be similar to the control group on the laser treatment group for three weeks. The change of the amplitude on the laser treatment groups for three weeks was significantly increased to be similar to normal group than that of the diabetic group. As the result, we thank that there were activately effected of lower power He-Ne IR laser on the heeling of the peripheral neurophathy in diabetic rats.