• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.155-160
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• 2005

Removal of methyl mercaptan was investigated using adsorption on virgin activated carbon (VAC) and modified activated carbons with acidic chemicals in the present work. CAC, NAC, AAC and SAC were represented as activated carbons modified with HCI, HNO$_{3}$, CH$_{3}$COOH and H$_{2}$S0$_{4}$ ,respectively The pore structures were evaluated using nitrogen isotherm. The surface properties of virgin activated carbon and modified activated carbons were characterized by EA, pH of carbon surface and acid value from Boehm titration. The modification of activated carbon with acidic chemicals resulted in a decrease in BET surface area, micropore volume and surface pH, but an increase in acid value. The order of the adsorption capacity of activated carbons was NAC>AAC>SAC>CAC>VAC, and in agreement with that of acid value of activated carbons, whereas in disagreement with that of micropore volume of activated carbons. It appeared that chemical adsorption played an important role in methyl mercaptan on modified activated carbons with acidic chemicals compared to virgin activated carbon. Modifying activated carbon with acidic chemicals enabled to significantly enhance removal of methyl mercaptan.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.315-320
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• 2008

This paper describes aerodynamic characteristics for the NREL(National Renewable Energy Laboratory) Phase VI rotor using the Fluent which is a commercial flow analysis tool. Aerodynamic analysis results are compared with experimental results by the NREL/NASA Ames wind tunnel tests. For three velocity cases, computed results are compared with experiment results at five spanwise positions. Computed results represented good agreement with the experimental results at low velocity. Otherwise computed results in suction side represents disagreement with the experimental results at high velocity. When interval between wind turbines is 10 times of rotor diameter, CFD research is performed to calculate the wake effect.

• Environmental Engineering Research
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• v.21 no.4
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• pp.420-426
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• 2016

Climate change imposes a huge treat on the sustainability of our environment. One of the major reasons for the increasing impacts of climate change is the emission of greenhouse gases. Therefore, cooperative greenhouse gas emission reduction schemes with a general consensus are needed in order to reduce the impacts of climate change. Due to the strong link between greenhouse gas emission and economic development there is disagreement among countries on the designing and implementation of emission reduction plans. In this paper the authors proposed a two-stage concession game to analyze emission reduction plans and determine a balanced emission range that improves the utilities of the bargaining parties. Furthermore the game was applied to a hypothetical example. Our results from the case study indicated that even though the utilities of the bargaining parties is highly affected by emission reductions, after making concessions their utilities can be improved given their emission reductions are within in a certain desirable range. The authors hope that this article provides insights which could be useful for understanding emission reduction plans and their consequences on the negotiating parties.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.7-16
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• 2011

This study discussed the applicability of satellite SAR (Synthetic Aperture Radar) imagery with regard to reservoir monitoring, and tried the extraction of reservoir storage from multi-temporal C-band RADARSAT-1 SAR backscattering images of Yedang and Goongpyeong agricultural reservoirs, acquired from May to October 2005. SAR technology has been advanced as a complementary and alternative approach to optical remote sensing and in-situ measurement. Water bodies in SAR imagery represent low brightness induced by low backscattering, and reservoir storage can be derived from the backscatter contrast with the level-area-volume relationship of each reservoir. The threshold segmentation over the routine preprocessing of SAR images such as speckle reduction and low-pass filtering concluded a significant correlation between the SAR-derived reservoir storage and the observation record in spite of the considerable disagreement. The result showed up critical limitations for adopting SAR data to reservoir monitoring as follows: the inappropriate specifications of SAR data, the unreliable rating curve of reservoir, the lack of climatic information such as wind and precipitation, the interruption of inside and neighboring land cover, and so on. Furthermore, better accuracy of SAR-based reservoir monitoring could be expected through different alternatives such as multi-sensor image fusion, water level measurement with altimeters or interferometry, etc.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.235-241
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• 2004

Computations were performed to investigate the effects of air staging on combustion in three stage heavy-oil fired combustion burner. The burner was designed for 3 MW. Different amounts of air are introduced into each 3 three stages by means of each dampers. The goal of the study is to understand combustion phenomena according to each air stage mass ratios through CFD. Air flow rates at three inlets are adjusted by dampers inside a burner. Here, injection conditions of liquid fuel are kept constant throughout all simulations. This assumption is made in order to limit the complexity of oil combustion though it may cause some disagreement. In case of cold flows, only longitudinal velocities arc considered, On the other hand, flow, temperature and NOx generations are taken into account for reactive flows. Simple parametric study was conducted by setting 1'st air stage mass ratio as a parameter. And an optimal operation condition was found. The computational study is based on k-e model, P-1 radiation model(WSGGM) and PDF, and is implemented on a commercial code, FLUENT.

• English Language & Literature Teaching
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• v.16 no.4
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• pp.133-152
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• 2010

There is disagreement, among researchers, on the benefits of corrective feedback on L2 learners' written output. Some scholars advocate the usefulness of corrective feedback while some claim that error correction is ineffective and even harmful. So far, however, research outcomes cannot settle this debate. Based on this debate, this study examines whether there is a difference among diverse types of feedback on the effects of L2 learners' writing improvement. This study found that teacher's direct feedback was more effective than any other types of feedback on the effect of participants' writing improvement. In particular, teacher's direct feedback helped their improvement on grammar, mechanics, and form. Among the types of peer feedback, self-correction was the most effective. In teacher feedback, form-focused feedback had more effects than content-focused feedback, but no difference with regard to peer feedback. In addition, teacher's content-focused feedback was more effective than peer's content-focused feedback. Overall, in all types of feedback, teacher feedback was more effective than peer feedback. However, direct (form-focused) feedback was the most effective in teacher feedback, and self-correction in peer feedback. The least effective feedback in both teacher and peer feedback was indirect (form-focused) feedback, which is simple underlining of errors.

• Journal of Technologic Dentistry
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• v.36 no.1
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• pp.17-23
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• 2014

Purpose: The purpose of this study was to analyze and compare the relative accuracy of digitized stone models of lower full arch, using two different scanning system. Methods: Replica stone models(N=20) were produced from lower arch acrylic model. Twenty digital models were made with the white light and blue LED($Medit^{(R)}$, Korea) scanner. Two-dimensional distance between the landmarks were measured on the Delcam $CopyCAD^{(R)}$(Delcam plc, UK). Independent samples t-test was applied for comparison of the groups. All statistical analyses were performed using the SPSS software package(Statistical Package for Social Sciences for Windows, version 12.0). Results: The absolute disagreement between measurements made directly on the two different scanner-based dental digital models was 0.02~0.04mm, and was not statistically significant(P>0.05). Conclusion: The precision of the blue LED optical scanner was comparable with the digitization device, and relative accuracy was similar. However, there still is room for improvement and further standardization of dental CAD technologies.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.10
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• pp.219-238
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• 1999

Obestity, characterized by an excess accumulation of fat, is a detriment to good health and wellbeing. It is easy for individuals to take on excess fat as soon as enough food and leisure are available in a society, causing an imbalance between energy intake and energy expenditure. Although there has been disagreement as to which side of this energy equation is more important in th epidemic of obesity, both sides are certainly involved. I think the prevalence of obesity begins with infancy. It seems to be relatively constant throughout childhood. Some retrospective studies have suggested that there is a direct progression from a fat chile to a fat adult. Obesity has been associated with excess mortality in many studies. The effect of obesity on cardiovascular disease has not always been an independent one, but has generally been through exacerbation of other rish factors such as hypertention, diabetes, hyperlipedmia, galbladder disease, gout and cancer of the grease and endometrium. The weights of identical twins raised in separate homes have been reported to be similar, thereby suggesting that heredity contributes significantly to weight. Overweight and obesity are by far greater health problems for many people in our society. Therefore in this paper we consider the relationship between body energy balance and problems of obesity. Whatever the weight of the person, the goal of the nutritionist and health care workers is to find solutions that will allow persons to feel better about themselves.

• Journal of Radiation Protection and Research
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• v.32 no.1
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• pp.15-20
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• 2007

An empirical formula fur the neutron dose equivalent at the maze entrance of medical accelerator treatment rooms was derived on the basis of a Monte Carlo simulation. The simulated neutron dose equivalents around the Varian medical accelerator by the MCNPX code were employed. Two cases of target rotational planes were considered: parallel and perpendicular to maze walls. Most of the maximum neutron dose equivalents at the doorway were found when the target rotational planes were parallel to maze walls and the beams were directed to the inner maze entrances. The neutron dose equivalents at the outer maze entrances were calculated for about 698 medical accelerator facilities which were generated from the geometry configurations of running treatment rooms, based on such gantry rotation that produces the maximum neutron dose at the doorway. The results calculated with the empirical formula in this study were compared with those calculated by the Kersey method for 7 operating facilities. It was found that the maximum disagreement between the calculation of this study and that of the Kersey method was a factor of 8.54 with the value calculated by the Kersey method exceeding that of this study. It was concluded that the kersey method estimated the neutron dose equivalent at the doorway computed by MCNPX more conservatively than this study technique.

• The Journal of Korean Academic Society of Nursing Education
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• v.10 no.2
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• pp.297-307
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• 2004

This study aims to identify the types and type-specific characteristics of subjectivity on complementary alternative therapy of nursing students using Q-methodology and to provide them as basic materials for nursing education. Q-methodology provides a scientific method for identifying perception structures that exist within certain individuals or groups. Thirty C college nursing students' classified 35 selected Q-statements into 9 points standard, according to the level of agreement or disagreement by forced normal distribution. The collected data was analyzed by using a QUNAL PC program. Resultingly, the attitude of nursing students regarding complementary alternative therapy was divided into three types. Type 1 is positive recognition. The students who think the therapy contributes to maintaining and improving health, and is a way to protect human body and improve welfare by enhancing immunity. Type 2 is objective acceptance. The students who think the complementary alternative therapy is effective when it is properly used for specific constitutions in discussion with medical teams after its effects are scientifically reviewed. Type 3 is popularity consideration. The students who put focus on its popular use and regard the therapy as very useful for not only patients but also ordinary healthy people because it is based on the natural and human approach. In conclusion, proposed are studies on influence factor of nursing students' awareness about the complementary alternative therapy and reviews on the effects of the complementary alternative therapy that is applied as nursing intervention.