• Environmental and Resource Economics Review
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• v.23 no.4
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• pp.583-615
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• 2014

Including the rolling black out in 2011, Korea has suffered from rapid increase of electricity consumption and demand forecasting failure for last five years. In addition, because of the Fukushima disaster, high fuel prices, and introduction of new generation sources such as renewables, the uncertainty on a power supply strategy increases. Consequently, a stable power supply becomes the new agenda and a revisino of strategy for new power generation sources is needed. In the light of this, we appraises the sixth basic plan for long term electricity demand and supply considering the changes of foreign and domestic conditions. We also simulate a strategy for the new power generation sources using a portfolio analysis method. As results, a diversity of power generation sources will increase and the share of renewable power generation will be surged on the assumptions of a cost reduction of renewable power sources and an increase of fuel costs. Particularly, on the range of a risk level(standard deviation) from 0.06 and 0.09, the efficient frontier has the most various power sources. Besides, the existing power plan is not efficient so that an improvement is needed. Lastly, the development of an electricity storage system and energy management system is necessary to make a stable and efficient power supply condition.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.204-213
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• 2008

Four ruminally cannulated Holstein cows averaging 43 days in milk (DIM) were used in a $4{\times}4$ Latin square to determine the effect of feeding extruded soybean, ground canola seed and whole cottonseed on ruminal fermentation and milk fatty acid profile. One hundred and twenty lactating Holstein cows, 58 (${\pm}31$) DIM, were assigned to four treatments in a completely randomized block design to study the effects of the three types of oilseeds on production parameters and milk fatty acid profile. The four diets were a control diet (CON) and three diets in which 10% extruded soybean (ESB), 5% ground canola seed (GCS) and 10% whole cottonseed (WCS) were included, respectively. Diets consisted of concentrate mix, corn silage and Chinese wild rye and were balanced to similar concentrations of CP, NDF and ADF. Ruminal fermentation results showed that ruminal fermentation parameters, dry matter intake and milk yield were not significantly affected by treatments. However, compared with the control, feeding cows with the three oilseed diets reduced C14:0 and C16:0 and elevated C18:0 and C18:1 concentrations in milk, and feeding ESB increased C18:2 and cis9, trans11 conjugated linoleic acid (CLA). Production results showed that feeding ESB tended to increase actual milk yield (30.85 kg/d vs. 29.29 kg/d) and significantly decreased milk fat percentage (3.53% vs. 4.06%) compared with CON. Milk protein (3.41%) and solid non-fat (13.27%) from cows fed WCS were significantly higher than from cows fed CON (3.24% and 12.63%, respectively). Milk urea N concentrations from cows fed the ESB (164.12 mg/L) and GCS (169.91 mg/L) were higher than cows fed CON (132.31 mg/L). However, intake of DM, 4% fat corrected milk, energy corrected milk, milk fat and protein yields, milk lactose percentage and yield, somatic cell count and body condition score were not affected by different treatments. The proportion of medium-chain fatty acid with 14 to 16 C units in milk was greatly decreased in cows fed ESB, GCS and WCS. Feeding ESB increased the concentration in milk of C18:1, C18:2, C18:3 and cis9, trans11-CLA content by 16.67%, 37.36%, 95.24%, 72.22%, respectively, feeding GCS improved C18:0 and C18:1 by 17.41% and 33.28%, respectively, and feeding WCS increased C18:0 by 31.01% compared with feeding CON. Both ruminal fermentation and production trial results indicated that supplementation of extruded soybean, ground canola seed and whole cottonseed could elevate the desirable poly- and monounsaturated fatty acid and decrease the medium chain fatty acid and saturated fatty acid content of milk fat without negative effects on ruminal fermentation and lactation performance.

• Environmental and Resource Economics Review
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• v.16 no.1
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• pp.27-63
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• 2007

Using the CGE model, this paper investigates economic impacts of a shortage in crude oil resulting from voluntary export restraints, OPEC's agreement of a cut in oil production, and/or a storing on speculation. Unlike most previous studies considering oil price as the unpredictable variable, this study constructs the model to determine the oil price endogenously under the condition of an insufficient supply of crude oil. According to IEA's extraordinary steps for a shortage of crude oil, we investigate an economic impact of 7~12% shortage below the level of business as usual. The results show that oil price soars by 17.3~33.5%, the rate of economic growth falls by 0.52~0.96%p, and the consumer price index(CPI) rises by 0.8~1.51%p. These results imply that increasing in 1%p of oil price results in decreasing in 0.03%p of economic growth and increasing in 0.045%p of consumer price index. The production of electricity declines because of the increase in production cost. A shortage of crude oil has an effect on sources of electricity. Most reduction in electricity generation occurs from the reduction in the thermal power generation which is highly dependent on crude oil. The shortage of crude oil causes demand for petroleum to significantly decline but demand for coal and heat to increase because of the substitution effect with petroleum. Demand for gas rise in the first year but falls from the second year.

• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.7-14
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• 2005

Traffic congestion causes enormous social costs as well as loss of travel time and waste of energy. Though the Seoul metropolitan government implemented various forms of transportation policies such as urban road pricing and public transportation reform, traffic volume which across the Seoul metropolitan borders have greatly increased because of housing land development in suburban area. The purpose of this study is to estimate individual's willingness-to-pay(WTP) for extensive implementation of congestion pricing through policy-mix with bus rapid transit(BRT) system. So the field survey interviews carried out. The empirical analysis was done with priority given to the following two topics; derivation of individual WTP and prior evaluation of policy effect from the equity aspect. To estimate individual WTP, we adopted contingent valuation method (CVM). The former is to estimate individual WTP for respondent's maintaining his/her transit pattern when he/she is faced with congestion pricing by using compensating variation(CV) concept. And, the latter aims at evaluating policy effect from the equity aspect by calculating the Proportion of WTP to average income using WTP in income bracket for policy scenarios.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.829-838
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• 2007

The stochiometric mix of evaporating materials for the $CdGa_2Se_4$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, $CdGa_2Se_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $630^{\circ}C$ and $420^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD).The carrier density and mobility of $CdGa_2Se_4$ single crystal thin films measured from Hall effect by van der Pauw method are $8.27{\times}10^{17}\;cm^{-3},\;345\;cm^2/V{\cdot}s$ at 293 K. respectively. The temperature dependence of the energy band gap of the $CdGa_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $Eg(T)\;=\;2.6400\;eV\;-\;(7.721{\times}10^{-4}\;eV/K)T^2/(T+399\;K)$. After the as-grown single crystal $CdGa_2Se_4$ thin films were annealed in Cd-, Se-, and Ga -atmospheres, the origin of point defects of single crystal $CdGa_2Se_4$ thin films has been investigated by PL at 10 K. The native defects of $V_{Cd}$, $V_{Se}$, $Cd_{int}$, and $Se_{int}$ obtained by PL measurements were classified as donors or accepters. We concluded that the heat-treatment in the Cd-atmosphere converted single crystal $CdGa_2Se_4$ thin films to an optical p-type. Also, we confirmed that Ga in $CdGa_2Se_4/GaAs$ did not form the native defects because Ga in single crystal $CdGa_2Se_4$ thin films existed in the form of stable bonds.

• The Korean Journal of Food And Nutrition
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• v.22 no.3
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• pp.430-442
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• 2009

This study was designed to investigate the relationship between the dietary intake according to calorie intake from a coffee containing beverage and the bone health status of 189 female collegians. The study was conducted through questionnaires, anthropometric checkup, 3-days food records and ultrasound measurement of calcaneus bone mineral density. Subjects were divided into three groups: students not drinking coffee(non-coffee group, N=56), students consuming <100 kcal daily from coffee(low-calorie coffee group, N=84), and students consuming $\geq100$ kcal of their total daily calories from coffee(high- calorie coffee group, N=49). There were no significant differences in weight, height, body mass index, body fat and calcaneus bone mineral density among the three groups. The low-calorie coffee group usually drank black coffee or instant coffee mix, and the high-calorie coffee group habitually drank coffee with milk or sugar syrup. There were no significant differences in the mean daily energy and food intake among the three groups. However, vitamin $B_2$(p<0.05) and calcium (p<0.01) intake in the high-calorie coffee group were higher than in the non-coffee group. Also, mean intake of sugars, fish and shellfishes, milks and beverages in the high-calorie coffee group were also significantly higher than in non coffee group(p<0.05). There was no significant difference in the Korean Dietary Diversity Score(KDDS) among the three groups. The main calcium source was milk in all three groups, and milk intake(total and included with coffee) was highest in the high-calorie coffee group. Although no significant difference was apparent between the high-calorie and non-coffee groups concerning anthropometric factors and calcaneus bone mineral density, consumption of coffee may have influenced food and nutrient intake. The results suggest that consumption of milk-supplemented coffee may be of nutritional benefit.

• Resources Recycling
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• v.27 no.2
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• pp.38-47
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• 2018

Integrated gasification combined cycle (IGCC) is a next generation energy production technology that converts coal into syngas with enhanced power generation efficiency and environmental performance. IGCC produces almost coal gasification slag as the solid by-product. IGCC slag is generated about 140,000 tons for a year although recycling of it is still in the early stages. We evaluated the potential of IGCC slag which is generated from a pilot plant in South Korea as an alkali-activated cement. Samples which were activated with the combined activator of sodium silicate solution and caustic soda had an average compressive strength of 4.5 MPa, showing expansion. Expansion of the alkali-activated slag was presumed to be caused by free CaO in the slag, although it was not detected by the ethylene glycol method. Samples that were activated with the combined activator of sodium aluminate and caustic soda had an average compressive strength of 10 MPa. Hydroxy sodalite and $C_3AH_6$ were found to be the new crystalline phases. IGCC slag can be used as an alkali-activated material, but the strength performance should be improved with proper mix design approach to calculate optimum proportions which can alleviate the expansion issue at the same time.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.759-766
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• 1998

It was determined whether thermoluminescence (TL) technique is a potential method to detect post-irradiation of dry soup base mix for instant noodle and its ingredients. The ingredients or the mixtures were irradiated, from which minerals were isolated using sodium polytungstate solution. Their TL signals (1st glow TL intensity/2nd glow TL intensity reirradiated at 48.6 Gy) were measured. The TL signals in temperature ranges of $229{\sim}295^{\circ}C$ and $229{\sim}361^{\circ}C$ showed larger differences between unirradiated and irradiated samples compared to other ranges. The average TL signals for unirradiated garlic powder, ginger powder, black pepper powder, onion powder, red pepper powder, and sesame seeds were below 0.2, while those for onion powder, red pepper powder, and sesame seeds irradiated at 10 kGy were over 20 in the two temperature ranges. The average TL signals for unirradiated soup mixture were 0.08 and 0.1, respectively, in the two temperature ranges, while those for the mixtures containing 10 kGy-irradiated onion powder, red pepper powder, and sesame seeds individually or in combination were over 7. The average TL signals for the mixtures irradiated 1, 5, and 10 kGy were over 10.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.252-258
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• 2018

A larger energy consumption and concentration of population induced green house gas glowing and heat island effect in the urban space. Roof green system was a effect method to reduce green house gas and heat concentration in the city. Therefore, construction of this system was increasing. Most of lightweight soil used in roof green system was perlite, but this caused dust and skin disease. So it needed to develop another new lightweight soli for roof green system. Meanwhile, a thermoelectric power plant generated bottom ash as a by-product. According to previous research, bottom ash could be used for artificial lightweight soil with 60 wt% of mixing rate. But this study was proceed to develop a artificial lightweight soil using bottom ash with higher mixing rate by 65 wt% and different organic ingredients. First, physical and chemical properties of bottom ash was investigated. Then test according to landscaping design standard was proceeded for various artificial lightweight soil mix types using bottom ash, bark, compost and coco peat. As a result, the artificial lightweight soil with 65% of bottom ash, 30% of bark and 5% of compost was suitable for low and middle range of soil standard.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.1-7
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• 2021

In response to the carbon emission reduction trends and the depletion of natural sand caused by the use of cement in construction works, graphene oxide and porous feldspar were applied as countermeasures in this study. By using (3-aminopropyl)trimethoxysilane-functionalized graphene oxide with enhanced bond characteristics, a concrete specimen was prepared with 5% less cement content than that in a standard mortar mix, and the compressive strengths of the specimens were examined. The compressive strengths of the specimen with (3-aminopropyl)trimethoxysilane-functionalized graphene oxide and porous feldspar and the specimen with standard mixing were 26MPa and 28MPa, respectively, showing only a small difference. In addition, both specimens met the compressive strength of cement mortar required for geotechnical structures. It is believed that a reasonable level of compressive strength was maintained in spite of the lower cement content because the high content of pozzolans, namely SiO₂ and Al₂O₃, in the porous feldspar enhanced the reactions with Ca(OH)₂ during hydration, the nano-sized graphene surface acted as a reactive surface for the hydration products to react actively, and the strong covalent bonding of the carboxyl functional group increased the bonding strength of the hydration products.