• Environmental and Resource Economics Review
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• v.27 no.3
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• pp.463-493
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• 2018

As the population structure of Korea changes with the increase of single households and elderly households, this may have effect on domestic energy consumption pattern. Our study analyzes whether the energy consumption of single and elderly households are distinguishable from those of general households. For empirical analysis, Household Energy Standing Survey panel data and regional fixed effect model are employed. The result strongly shows that single households consume more energy than other households. The consumption of single households from 40s to 60s was the highest. On the other hand, the effect of aging was different from energy sources. Electricity consumption of elderly household was more than other age groups, while oil consumption of elderly household was less than others. Gas and total energy consumptions turned out to be not much different among different age groups.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.130.2-130.2
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• 2011

본 연구에서는 RF magnetron sputtering을 이용하여 실리콘 박막 태양전지용 ZnO:Al 전면전극을 제작하고 다양한 식각조건에 따른 ZnO:Al 박막의 표면형상 변화와 함께 전기적 및 광학적 특성 변화를 조사하였다. pin 구조를 갖는 실리콘 박막 태양전지의 효율 향상을 위해서는 입사광의 산란효과에 따른 광포획 증가가 필수적이며 이를 위하여 ZnO:Al 전면전극의 표면텍스처링 형성이 필요하다. 식각용액으로는 HCl과 HF 등을 사용하였으며 식각용액 농도 및 식각시간을 변화시켰다. 식각 후의 ZnO:Al 박막의 표면형상은 SEM(Scanning Electron Microscope)과 AFM(Atomic Force Microscope)을 이용하여 분석을 하였고, UV-visible-nIR spectrometer를 이용하여 총 투과도 및 산란 투과도를 측정하였다. 이 외에도 four-point probe 및 Hall measurement를 이용하여 전기적 특성 변화를 조사하였다. 다양한 식각조건에 따라 제조된 ZnO:Al 박막 위에 실리콘 박막 태양전지를 제작하여 전면전극의 표면형상에 따른 태양전지 성능변화를 비교 분석하였다.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.903-914
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• 2008

This study was undertaken for the production capacity expansion and energy saving through entire process simulation and optimization for the commercial process of manufacturing monoethylene glycol as a staple from ethylene oxide. Aspen $Plus^{TM}$(ver. 2006) was employed in the simulation and optimization work. The multicomponent vapor-liquid equilibria involved in the process were calculated using the NRTL-RK equation. As for the binary interaction parameters required for a total of 91 binary systems, those for 8 systems were self-supplied by the simulator, those for 28 systems were estimated through regression of the VLE data in the literature, and the remainder were estimated with the estimation system built in the simulator. Subsequent to ascertaining the accuracy of the generated parameters through comparison between actual and simulated process data, sensitive variables highly affecting the process were searched and selected using sensitivity analysis tool in the simulator. The optimum operating conditions minimizing the total heat duty of the process were investigated using the optimization tool based on the successive quadratic programming in the simulator.

• Journal of Nutrition and Health
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• v.54 no.3
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• pp.247-261
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• 2021

Purpose: This study was conducted to identify the association between insulin resistance and the major dietary patterns of Korean adults. Methods: This study used data from the 2015 Korea National Health and Nutrition Examination Survey. The subjects were 2,276 adults aged 19 to 64 years old. Based on the food frequency questionnaire data, 112 food items were reclassified into 30 food groups. The principal component analysis method was applied to identify major dietary patterns. We used homeostatic model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) value as indicators of insulin resistance. The association between major dietary patterns and insulin resistance was investigated using logistic regression analysis. Results: Three major dietary patterns were identified and assigned descriptive names based on the food items with high loadings: 'healthy Korean meal pattern', 'western meal pattern', and 'white rice, alcohol, meat pattern'. As the 'white rice, alcohol, meat pattern' score increased, significant increasing trends for fasting glucose concentration and HOMA-IR and a significant decreasing trend for QUICKI were observed after adjusting for age and sex. The odds ratio of insulin resistance according to the 'healthy Korean meal pattern' and the 'western meal pattern' were not statistically significant. the 'white rice, alcohol, meat pattern' showed a significant positive association with the risk of insulin resistance after adjusting for covariates. Conclusion: These results suggest that the 'white rice, alcohol, meat pattern' is positively associated with the risk of insulin resistance. The white rice, alcohol, meat pattern was related to the high consumption of alcohol together with rice or meat. This pattern was also associated with the high intake of sodium and low intakes of vitamin C, calcium, potassium, and dietary fiber. To confirm the association, further longitudinal studies are required.

• Journal of Nutrition and Health
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• v.55 no.5
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• pp.558-571
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• 2022

Purpose: The purpose of this study was to analyze the dietary intake of Korean adults with atopic dermatitis (AD) to determine whether the risk of developing AD was related to their diet. Methods: Among the participants in the 7th National Health and Nutrition Survey (2016 to 2018), 10,571 adults aged 19-64 were divided into AD (AD group, n = 366) and control groups (non-AD group, n = 10,205) to compare and analyze their nutrient intake status and Korean Healthy Eating Index (KHEI) score. Depending on the prevalence of AD, the nutrient intake, nutrient intake per 1,000 kcal, acceptable macronutrient distribution range, and KHEI score were tested for significance by correcting for age, sex, body mass index, education, marriage, occupation, residence area, physical activity, and energy intake variables that were derived for confounding factors. Results: The acceptable macronutrient distribution range for protein was lower in the AD group than in the non-AD group. Comparing the nutrient intake per 1,000 kcal, the intakes of protein, phosphorus, iron, and potassium of the AD group were significantly lower than those of the non-AD group. In the KHEI, the scores of total vegetables, vegetables excluding kimchi and pickles, meat, fish, eggs, and legumes of the AD group were significantly lower than those of the non-AD group. In addition, as these food intake scores increased, the risk of AD significantly decreased. Conclusion: In conclusion, adult AD patients had low intakes of vegetables, meat, fish, eggs, and legumes, and it was confirmed that high intakes of these foods may be associated with low AD risk. Therefore, we suggest that an adequate intake of vegetables and foods containing protein would be necessary for the management and treatment of AD in adults.

• Journal of Energy Engineering
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• v.15 no.1 s.45
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• pp.14-22
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• 2006

Various pros and cons are raised as to the nuclear and renewable power portions. In order to generate scientific, objective, and comparative data, this study reviewed energy policies of some countries and derived 34 possible energy mix scenarios depending on the nuclear portion, the renewable portion and the make-up power sources. For each scenario, the unit electricity cost was calculated using the BLMP (Base Load Marginal Price) and SMP (System Marginal Price) methodology, which is currently adopted in Korean electricity market. The unit electricity cost for the current energy mix was 22.18 Won/kWh and those fir other scenarios spreaded from 19.74 to 164.07 Won/kWh excluding the transmission costs and profits of the electric utility companies. Generally, the increased nuclear power portion leads reduction in the unit electricity cost while the trend is reversed in the renewable power portion. Notable observation is that when the renewable power portion exceeds 20%, as the scenario cannot enjoy the benefit of cheap base load, the unit electricity cost at low demand time zone is increased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.179-183
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• 1980

The efficiency of energy transfer by a population of the farmed pacific oyster, Crassostrea gigas was studied during culture period of 10 months July 1979-April 1980, in Geoje-Hansan Bay near Chungmu City. Energy use by the farmed oyster population was calculated from estimates of half-a-month unit age specific natural mortality rate and data on growth, gonad output, shell organic matter production and respiration. Total mortality during the culture period was estimated approximate $36\%$ from data on survivor individual number per cluster. Growth may be dual consisted of a curved line during the first half culture period (July-November) and a linear line in the later half period (December-April). The first half growth was approximated by the von Bertalanffy growth model; shell height, $SH=6.33\;(1-e^{0.2421(t+0.54)})$, where t is age in half-a-month unit. In the later half growth period shell height was related to t by SH=4.44+0.14t. Dry meat weight (DW) was related to shell height by log $DW=-2.2907+2.589{\cdot}log\;SH,\;(2, and/or log $DW=-5.8153+7.208{\cdot}log\;SH,\;(5. Size specific gonad output (G) as calculated by condition index of before and after the spawning season, was related to shell height by $G=0.0145+(3.95\times10^{-3}{\times}SH^{2.9861})$. Shell organic matter production (SO) was related to shell height by log $SO=-3.1884+2.527{\cdot}1og\;SH$. Size and temperature specific respiration rate (R) as determined in biotron system with controlled temperature, was related to dry meat weight and temperature (T) by log $R=(0.386T-0.5381)+(0.6409-0.0083T){\cdot}log\;DW$. The energy used in metabolism was calculated from size, temperature specific respiration and data on body composition. The calorie contents of oyster meat were estimated by bomb calorimetry based on nitrogen correction. The assimilation efficiency of the oyster estimated directly by a insoluble crude silicate method gave $55.5\%$. From the information presently available by other workers, the assimilation efficiency ranges between $40\%\;and\;70\%$. Twenty seven point four percent of the filtered food material expressed by energy value for oyster population was estimated to have been rejected as pseudofaeces : $17.2\%$ was passed as faeces; $35.04\%$ was respired and lost as heat; $0.38\%$ was bounded up in shell organics; $2.74\%$ was released as gonad output, $2.06\%$ was fell as meat reducing by mortality. The remaining $15.28\%$ was used as meat production. The net efficiency of energy transfer from assimilation to meat production (yield/assimilation) of a farm population of the oyster was estimated to be $28\%$ during culture period July 1979-April 1980. The gross efficiency of energy transfer from ingestion to meat production (yield/food filtered) is probably between $11\%\;and\;20\%$.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1362-1366
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• 1998

The sterilizing effect of electron beam was compared with that of gamma irradiation for commercial ginseng powders. White and red ginseng powders were contaminated by about $10^5\;CFU/g$ of total bacteria and by $10^3\;CFU$ of coliforms only in white ginseng powder. Data of microbial population for the sterilizing effect of electron beam irradiation showed that no microorganisms were detected in the samples irradiated up to 7.5 kGy for total aerobic bacteria and 2.5 kGy for molds and coliforms. Such doses were effective for controlling the microbial growth in the samples during 4 months of storage at room temperature. Decimal reduction doses $(D_{10}$ value) on the initial bacterial populations were $2.85{\sim}3.75\;kGy$ in electron beam and $2.33{\sim}2.44\;kGy$ in gamma irradiation, which were influenced by the initial microbial loads and the energy applied. Compared with gamma irradiation, electron beam showed a similar result in its sterilizing effect on ginseng powders, suggesting its potential utilization in due time.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.1-10
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• 2007

This study was reviewed on the bioethanol production from biomass resources and feedstock supply in America. U.S. Department of Energy (USDE) and the u.s. Department of Agriculture USDA) are both strongly committed to expand the role of biomass as an energy source. They support biomass fuels and products as a way to reduce the need for oil and gas imports, to strengthen the nation's energy security and environmental quality. And it was envisioned a 20 percent replacement of the current U.S.transportation fuel consumption in 2030. Also it was reviewed policies to encourage the expanding of Bio-based fuel use to replace gasoline, such as Clean Air Act, Federal Clean Fuel Program and American Jobs Creation Act. In feedstock supply it was assumed forest biomass will be supplied in 368 million dry tons yearly and the agriculture derived biomass adopted by new technologies and land use change will be supplied in 998 million dry tons, including highly 818 million dry tons of lignocellulosic biomass such as perenial crops (hybrid trees, grasses) corn stover, other crop residues. This amount is 5 times to the amount from based current agricultural technology and crop land.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.476-491
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• 2022

Purpose: The purpose of this study was to evaluate the energy and nutrient contents of home meal replacement (HMR) rice products per single serving package based on nutrition labels. Methods: The market research was conducted from February to July 2021 on products sold on the internet, at convenience stores, etc. A total of 406 products were investigated. The products were divided into the following 6 classifications: instant rice (n = 45), cup rice (n = 64), frozen rice (n = 188), rice bowls with toppings (n = 32), gimbap (n = 38), and triangular gimbap (n = 39). Results: The mean packaging weight per serving was the highest in the rice bowl with toppings at 297.1 g, followed by cup rice (264.0 g), frozen rice (239.5 g), gimbap (230.2 g), instant rice (193.4 g), and triangular gimbap (121.6 g) (p < 0.001). The energy per serving package for the rice bowl with toppings was significantly the highest at 496.0 kcal (p < 0.001). The sodium content per serving package of gimbap was the highest at 1,021.8 mg and that of the instant rice was lowest at 37.4 mg (p < 0.001). The price per serving package of the rice bowl with toppings at 4,333.8 won was the highest. The contribution to the daily nutritional value per serving package of all types of HMR rice products surveyed showed an average range of 10-25% for energy, 11-22% for carbohydrates, and 2-51% for sodium. Conclusion: These results indicate the energy and nutrient contents of HMR rice products, vary by type. Therefore, consumers should review the nutrition labeling to select an appropriate HMR rice product based on their intended consumption.