• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.5
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• pp.205-211
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• 2015

Most of the sulfur is obtained from desulfurization of natural gas and crude oil. In Korea, more than 120 tons of sulfur are produced by refinery, and about 50 % of the produced sulfur is used as a raw material for the production of fertilizer and sulfuric acid. Modified sulfur is manufactured from excessive sulfur that could be used to improve concrete properties, and this study evaluated concrete strength and durability that contains modified sulfur. Flexural and compressive strengths of concrete with sulfur modified polymer were comparable to those of OPC concrete with mixing water at similar temperatures, while the strengths increased a little as mixing water temperature increased. It was also confirmed that the resistance to freeze-thaw damage was more dependent on entrained air characteristics obtained by a proper use of air entraining agent than on the use of sulfur modified polymer. When concrete was immersed in 5 % sulfuric acid, the rate of reduction in compressive strength of OPC concrete was less than 1/4 of the strength reduction of concrete with sulfur modified polymer. Also, the resistance of concrete with sulfur modified polymer to scaling due to the use of de-icing salt was evaluated as Class 1, while that of OPC concrete was evaluated as Class 4, as aggregates were exposed. Accordingly, it is believed that sulfur modified polymer could be effectively used for bridge deck concrete since sulfur modified polymer improves the durability of concrete.

• Journal of Digital Contents Society
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• v.4 no.2
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• pp.211-221
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• 2003

The objective of this paper is performance analysis of the digital document image decimation algorithm which generates a value of decimated element by an average of a target pixel value and a value of neighbor intelligible element to adaptively reflect the merits of ZOD method and FOD method on the decimated image. First, a target pixel located at the center of sliding window is selected, then the gradient amplitudes of its right neighbor pixel and its lower neighbor pixel are calculated using first order derivative operator respectively. Secondly, each gradient amplitude is divided by the summation result of two gradient amplitudes to generate each local intelligible weight. Next, a value of neighbor intelligible element is obtained by adding a value of the right neighbor pixel times its local intelligible weight to a value of the lower neighbor pixel times its intelligible weight. The decimated image can be acquired by applying the process repetitively to all pixels in input image which generates the value of decimated element by calculating the average of the target pixel value and the value of neighbor intelligible element. In this paper, the performance comparison of proposed method and conventional methods in terms of subjective performance and hardware complexity is analyzed and the preferable approach for developing the decimation algorithm of the digital document image on the basis of this analysis result has been reviewed.

• Management & Information Systems Review
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• v.35 no.4
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• pp.185-211
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• 2016

This study examined the impact of learning organization activities on burnout and the moderating effect of supervisor trust in a learning organization. The results of the study shows that among the activities of a learning organization, independent variables in this study, promoting inquiry and dialogue as well as encouraging collaboration and team learning affect burnout. In other words, the dedication of an organization to creating a culture in which various learning approaches are experimented through questioning and giving feedback as well as collaborative learning that can reinforce the effective use of team resources have an impact on reducing emotional exhaustion, which is considered to be at the core of burnout. Plus, these factors reduce impersonalization, which is activated to prevent further emotional exhaustion by dealing with customers, colleagues and jobs in a cold, negative and perfunctory way. In this study, the dimensions of promoting inquiry and dialogue as well as encouraging collaboration and team learning were found to reduce the decline in personal sense of achievement of an employee with a negative assessment of himself or herself derived from a lack of achievement in his or her job. Supervisor trust (integrity, benevolence and ability) had a moderating effect on the relationship between strategic learning leadership and impersonalization/emotional exhaustion. This suggests that the trust of supervisor helps mediate and moderate the emotional exhaustion and impersonalization of organizational members by encouraging leaders to drive change and take the organization to a new direction. The study has provided implications that communication plays an important role in reducing burnout in the learning context such as positive, appreciative inquiry and feedback analysis to identify strength, and that supervisor trust is critical in order to ensure strategic learning leadership exerts greater influence on the organization.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.2
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• pp.200-211
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• 1999

For many years permanent soft denture liners has been widely used in dental practice directly or indirectly because of its function in absorbing and distributing the impact force. However, it reveals problems such as lack of permanency and decreased bond strength in long term use. The purpose of this study is to measure the bond strength and failure between denture base resin and several permanent liners. Lucitone 199 was used as denture base resin with soft acrylic liners (Triad, Tokuso Rebase) and silicone elastomers (Tokuyama, Ufi Gel C) bonded to measure the tensile strength before and after thermocycling. The thermocycling was done in 2000 cycles at $5^{\circ}C,\;26^{\circ}C\;and\;55^{\circ}C$ and the measured tensile strength values before and after thermocycling were compared. The mode of failure was investigated in the separated specimens. The results are as follows. 1. As to tensile strength, the strongest material is Tokuso Rebase followed by Triad, Tokuyama, Ufi Gel C in before thermocycling and the order of Triad, Tokuso Rebase, Tokuyama, Ufi Gel C in after thermocycling state. There was significant difference between the values of Triad, Tokuso Rebase and Tokuyama, Ufi Gel C(p<0.05). 2. As to degree of displacement, Ufi Gel C showed most displacement with or without thermo-cycling treatment and also the difference was significant with the other materials(p<0.05). 3. As to comparisons before and after thermocycling, Tokuso Rebase and Tokuyama showed significant difference in bond strength, whereas Triad and Tokuso Rebase showed significant difference in the degree of displacement(p<0.05). 4. In debonded specimens, Triad and Ufi Gel C showed adhesion failure and Tokuyama showed cohesion failure. Both failures were observed in Tokuso Rebase with adhesion failure up to 70%. The results of this study showed that degree of bond strength between permanent soft denture liner and denture base resin were variable. There was a significant difference between soft acrylics and silicone elastomers with regard to bond strength. Further research in improving bond strength of widely used silicone elastomers and in developing the method of measuring bond strength between denture base resin and the lining materials is needed.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.211-220
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• 1995

Though the endometriosis is not always related with infertility, endometriosis causes infertility in some patients. There are many treatment modalities of infertile patients who have endometriosis. In recent years, Assisted Reproductive Technology(ART) have been widely accepted as being a useful tool for the treatment of infertile endometriotic patients. The objective of this study was to evaluate the outcome of ART in infertile endometriotic patients who have been carried out IVF-ET from Jan, 1992 to Dec, 1994 and to compare the results between COH/IUI and IVF-ET in the patients with endometriosis stage I. Tubal disease only patients were grouped(308 patient, 956 cycles) as a control. Endometriosis group was subdivided into 4 groups according to American Fertility Society classification; endometriosis stage I (45 patients, 61 cycles), stage II (26 patients, 39 cycles), stage III (26 pateitns, 37 cycles), stage IV (33 patients, 50 cycles). The outcomes of IVF-ET in endometriosis patients were as follows; The oocyte recovery rates were significantly lower in stage III, IV endometriosis. In case of stage III endometriosis, the fertilization rate was significantly lower than other stages of endometriosis. Clinical pregnancy rates per cycle were not different between the tubal group(22%) and the endometriosis group(25%). According to endometriosis stage, the implantation rate and clinical pregnancy rate were significantly lower in stage IV (5.6%, 16%) compared with other stages (I; 10.0%, 26%, II;9.8%, 31%, III;12.6%, 32%). It suggests that some factor like autoantibodies may inhibit implantation of embryos in stage IV endometriosis. To evaluate the possibility that simply increasing the number of gametes at the site of fertilization might account for pregnancies attributed to IVF-ET, the authors retrospectively analyzed the outcome of couples undergoing IUI during hMG cycles and CC cycles between 1992 and 1994 in the women with endometriosis stage 1. In case of stage I endometriosis, though the COH/IUI group showed lower FSH level and lesser age profile than IVF-ET group, IUI group has resulted in lower pregnancy rates(19.2%) compared with the IVF-ET group(26.2%). In conclusion, endometriotic infertile patients can get comparable pregnancy rates with the tubal factor infertility patients during IVF-ET program. Moreover even in stage I endometriosis, IVF-ET may be an more effective treatment modality than COH/IUI.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.206-211
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• 2000

The purpose of this study was to investigate the effect of germinated buckwheat on blood pressure, plasma glucose and lipid levels of spontaneously hypertensive rats(SHR). The male and female SHR were divided into two groups. After feeding the germinated buckwheat diet(50%, w/w) ad libitum for 6 weeks, the weight gain of the germinated buckwheat group in male rats was higher than those of control group. Systolic blood pressure of the germinated buckwheat group in male rats was significantly decreased at 6 weeks by 3%. The fasting glucose levels of the germinated buckwheat group had a tendency to be lower compared with those of the control group. Total cholesterol, HDL-cholesterol and HTR of female SHR fed the germinated buckwheat diet were significantly increased compared to the control diet. Atherogenic index of the germinated buckwheat group was decreased in males(ns) and females(p<0.05) than those of the control group. From these results the germinated buckwheat might be useful for anti-hypertensive and anti-hyperlipidemic agents.

• Communications of Mathematical Education
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• v.22 no.2
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• pp.211-227
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• 2008

The method of being composed of small groups has a strong influence on mathematics and cooperative learning and therefore, the group classification should be made in a way of considering not only a learner's cognitive factor but also a affective factor in order to maximize the effects. In this research, we regarded personality as the important standard of the group classification for cooperative learning and tried to find out the influence on the mathematical attitude and achievement in mathematics by means of conducting mathematics and cooperative learning according to the personality types. In order to resolve this problem, we performed the cooperative learning of small group subject to the students at year 6 in an elementary school by making up a similar personality type of group and a different personality type of group through MMTIC examination, and also tried to find out any significant difference in terms of mathematical attitude and achievement in mathematics between two groups. The results obtained in this research are as follows; First, organizing groups in accordance with personality types did not affect on mathematical attitude. Although there were some positive opinions towards mathematics and cooperative learning, the both similar personality type of group and different personality type of group showed no significant difference in terms of mathematical attitude between two groups. Second, organizing groups in accordance with personality types showed positive effects on the achievement in mathematics. The similar personality type of group showed the better achievement in mathematics than the different personality type of group.

• Journal of muscle and joint health
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• v.17 no.2
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• pp.203-211
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• 2010

Purpose: We aimed to test the validity of the EQ-5D (Euro-Quality of Life-5 Dimension), a brief and simple instrument, in measuring health related quality of life in the patients with osteoarthritis. Methods: 183 participants attending the education programs for osteoarthritis patients at the Health Centers located in Seoul and Gyunggi province area during the periods of June to December in 2009 were interviewed with the EQ-5D and KWOMAC (Korean version of Western Ontario and McMaster Scale). The data were analysed with Spearman correlation coefficents and t-test by using of SPSS/WIN 12.0 version. Results: There was a negative correlation between knee pain, stiffness and difficulty in usual activity of sub category items of KWOMAC and EQ-5Dindex, while there was no correlation between these categories and EQ-VAS. Moreover, as a result of comparing the score of physical function measured by KWOMAC according to the severity degree of the EQ-5Dindex, the group of advanced stage having moderate and severe symptoms reported significantly higher scores of physical function than those of groups having no health problems. Conclusion: The EQ-5D is an acceptable and valid instrument for measuring health-related quality of life in patients with osteoarthritis.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.204-211
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• 2018

In this study, densities of water + N-Methyldiethanolamine (MDEA), Water + 2-Amino-2-Methyl-1-Propanol (AMP), MDEA + AMP binary systems and Water+MDEA+AMP ternary system were measured over the full range of composition at temperatures from 303.15 K to 333.15 K by using an Anton Paar digital vibrating tube densimeter (DMA4500). The experimental excess volumes have been obtained from the experimental density results and have been fitted using the Redlich-Kister-Muggianu expression. The parameters obtained from the binary excess volume data were used for the correlation of ternary system with one additional ternary parameter for each isotherm. All investigated binary and ternary systems are completely miscible, because the values of excess volume are negative under the examined conditions.

• Journal of Environmental Impact Assessment
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• v.13 no.4
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• pp.197-211
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• 2004

Visibility impairment was known as an indicator of the increased air pollution. In many previous studies, it is known that both directly emitted fine particles mainly from vehicles and secondary aerosols from photochemical reactions could contribute to this visibility impairment in addition to the meteorological condition. Furthermore, the visibility showed different change patterns according to the geographical condition. In order to research into the influence of these factors on visibility, this study analyzed the visibility at 15:00, observed from 1990 to 2001 in Seoul, Ganghwa, Susan, Gwangju, Jeju. As a result, the visibility was increased in Seoul except the rainfall period, but in Susan, Gwangju, Jeju, it decreased with the relative humidity (RH). Especially, in Seoul, the number of low visibility days was larger than other sites and variations of the visibility were sensitive to the concentration of air pollutants, such as TSP, $NO_2$, $O_3$. The visibility impairment was mainly observed in meteorological condition of RH<50% and relatively stationary front. Therefore it is inferred that photochemical smog could lead to the low visibility in Seoul. On the other hands, in Ganghwa and Susan, when RH was 60~70%, the low visibility observed under the influence of the transports of air pollutants from nearby cities as well as humid air mass from coastal region. And in Jeju, sea fog and humid air mass caused the visibility impairment when the RH was larger than 80%. Finally, during the observational period, some cases of low visibility phenomena were simultaneously observed in the vast region including Seoul, Susan, Ganghwa. It not only includes the visibility aggravation by Asian Dust, but also could be caused by the movement and diffusion of flying dust or secondary aerosols. Moreover, the result shows that these phenomena could be mainly influenced by meteorological factors covering the wide regions.