• Journal of Energy Engineering
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• v.28 no.3
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• pp.65-79
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• 2019

The study attempted to estimate the optimal facility capacity by combining renewable energy sources that can be connected with gas CHP in industrial complexes. In particular, we reviewed industrial complexes subject to energy use plan from 2013 to 2016. Although the regional designation was excluded, Sejong industrial complex, which has a fuel usage of 38 thousand TOE annually and a high heat density of $92.6Gcal/km^2{\cdot}h$, was selected for research. And we analyzed the optimal operation model of CHP Hybrid System linking fuel cell and photovoltaic power generation using HOMER Pro, a renewable energy hybrid system economic analysis program. In addition, in order to improve the reliability of the research by analyzing not only the heat demand but also the heat demand patterns for the dominant sectors in the thermal energy, the main supply energy source of CHP, the economic benefits were added to compare the relative benefits. As a result, the total indirect heat demand of Sejong industrial complex under construction was 378,282 Gcal per year, of which paper industry accounted for 77.7%, which is 293,754 Gcal per year. For the entire industrial complex indirect heat demand, a single CHP has an optimal capacity of 30,000 kW. In this case, CHP shares 275,707 Gcal and 72.8% of heat production, while peak load boiler PLB shares 103,240 Gcal and 27.2%. In the CHP, fuel cell, and photovoltaic combinations, the optimum capacity is 30,000 kW, 5,000 kW, and 1,980 kW, respectively. At this time, CHP shared 275,940 Gcal, 72.8%, fuel cell 12,390 Gcal, 3.3%, and PLB 90,620 Gcal, 23.9%. The CHP capacity was not reduced because an uneconomical alternative was found that required excessive operation of the PLB for insufficient heat production resulting from the CHP capacity reduction. On the other hand, in terms of indirect heat demand for the paper industry, which is the dominant industry, the optimal capacity of CHP, fuel cell, and photovoltaic combination is 25,000 kW, 5,000 kW, and 2,000 kW. The heat production was analyzed to be CHP 225,053 Gcal, 76.5%, fuel cell 11,215 Gcal, 3.8%, PLB 58,012 Gcal, 19.7%. However, the economic analysis results of the current electricity market and gas market confirm that the return on investment is impossible. However, we confirmed that the CHP Hybrid System, which combines CHP, fuel cell, and solar power, can improve management conditions of about KRW 9.3 billion annually for a single CHP system.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.105-117
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• 2019

In order to investigate the characteristics of benthic macroinvertebrate communities in the Gihwa stream, a tributary of the Dong River, we surveyed the community and environmental factors in April and November 2013 at 6 sites. The benthic macroinvertebrate taxa represented total 63 species belonging to 29 families, 12 orders, 5 classes and 4 phyla. Total 48 (10~28 in each site) species were collected in April and 44 (13~24 in each site) in November. The number of individuals increased slightly from $560{\sim}2,290m^{-2}$ in April to $806{\sim}3,674m^{-2}$ in November. Chironomidae spp. was dominant species in April and Stenopsyche bergeri was dominant species in November. In the Functional Feeding Groups, Gathering-collector(53.9%) was dominant in April, while Filtering-collector (44.3%) increased in November. Intolerant order category (i.e. EPT species richness) in St.1, St.5 and St.6 increased in November compared to April due to the increase of Trichoptera. St.2, St.3 and St.4, which were located near the fish farm, were low EPT as a whole, but Benthic macroinvertebrate index (BMI) was good state in November than April due to decrease of Chironomidae spp.. The environmental factors in the survey site showed similar tendency except for St.1 between both seasons, and electrical conductivity, salinity, and water width showed seasonal differences. Cluster analysis and Nonmetric multidimensional scaling (NMDS) based on benthic macroinvertebrate community data were divided into two groups according to season. Electrical conductivity, salinity and substrate composition were the most influential factors determining the distribution patterns of macroinvertebrate communities.

• Korean Journal of Psychosomatic Medicine
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• v.29 no.1
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• pp.58-66
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• 2021

Objectives : The purpose of this study is to compare the psychosocial characteristics of patients diagnosed with functional gastrointestinal disorder (FGID) by classifying them into irritable bowel syndrome (IBS), functional dyspepsia (FD), functional constipation (FC), functional heartburn (FH) groups, and overlap group (two or more functional diseases) and to examine the factors associated with the quality of life (QoL) of patients with FGID. Methods : A total of 144 patients who were diagnosed with FGID were selected as the subjects. The demographical factors were investigated; Korean-Beck Depression Inventory-II (K-BDI-II), Korean-Beck Anxiety Inventory (K-BAI), Korean version of Childhood Trauma Questionnaire (K-CTQ), Multi-dimensional Scale of Perceived Social Support (MSPSS), Korean Version of Connor-Davidson Resilience Scale (K-CD-RISC), and World Health Organization Quality of Life Assessment Instrument Brief Form (WHOQOL-BREF) were used to evaluate the psychosocial factors. Results : TThe overlap group had a significantly higher K-BDI-II score (F=11.09, p<0.001) and K-BAI score (F=8.93, p<0.001) compared to other groups. In childhood trauma, the IBS patients had a difference in emotional neglect (F=2.54, p=0.04) than the FD patients. The QoL of FGID patients had a negative correlation with depression (r=-0.196, p<0.01), anxiety (r=-0.235, p<0.01), and childhood trauma (r=-0.222, p<0.01), and a positive correlation with social support (r=0.512, p<0.01) and resilience (r=0.581, p<0.01). Conclusions : Overlap group had a higher level of depression and anxiety, and the IBS patient group had a higher level of emotional neglect than the FD patient group in terms of childhood trauma.

• Journal of Korean Academy of Dental Administration
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• v.5 no.1
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• pp.1-12
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• 2017

Although dental hygienists have performed chair-side assisting and other dental cares as well as preventive dental cares in Korea, medical technician law confines duties of dental hygienists as closed narrative. The aim of this study was to investigate difference in perception of duties of dental hygienists in dental clinic between dentists and dental hygiene students. A total of 245 copies of questionnaires were distributed to dentists and students by post-mail. Only 42 dentists and 30 students in an area replied these questionnaires about the present and future duties of dental hygienists after providing written consent. Both groups agreed that intra and extra oral X-ray taking, education about oral health behavior, instruction after dental treatment, chair-side assisting, consulting for patients, scaling, initial impression taking, management of dental materials and equipment, sterilization of equipment, and receiving dental bills are duties of dental hygienists. However, they had different perceptions about various dental treatments as duties of dental hygienists even if they were under instructions of a dentist, including infiltration anesthesia, filling in cavity, intramuscular injection, FC change, canal irrigation, orthodontic treatment including separating, ligature bracket bonding and removing, setting crown and bridge, making individual, removing implant screw, and so on. These findings demonstrated that there were different perceptions about duties of dental hygienists between dentists and dental hygiene students, especially on dental treatment.

• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.85-92
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• 1999

This study was designed to determine effect of cryoprotectant kinds and cell stages on OPP vitrification method in mouse embryos. The freezing speed, cryoprotectants and cell stage could affect of embryo viability following various vitrification methods. The vitrification solution used were consisting of 40% (v/v) ethylene glycol, 18% (w/v) Ficoll, 0.3 M sucrose solution in holding medium (D-PBS supplemented with 5% FCS: HM) (EFS) or 16.5% ethylene glycol , 16.5% dimethyl sulfoxide, 0.5 M sucrose in HM (EDS). The embryos were collected from oviduct at 18 h after hCG injection and then washed and cultured in mHTF medium until use. In experiment 1, the blastocysts were vitrified by OPP straw to determine the optimal vitrification solution of EFS or EDS. The post-thaw survival rates at re-expanded stage rates were significantly different between EFS and EDS (95.0 vs 100%), but at hatching stage was not different between EFS and EDS (90.0 vs 95.0%). respectively. In experiment 2, zygotes, 2-, 4-cell, morula and blastocysts were vitrified by OPP method to determine the acceptable of early stage embryos. The development rates to expanded blastocyst in zygote (70.0%) were significantly lower rather than those in 2-, 4- 8-cell, compacted morula or blastocyst (89.7, 90.0, 92.8, 97.6 or 97.5%), respectively. However, the cell number of post-thaw developed to expanded blastocyst in blastocyst and control blastocyst stage (39.6$\pm$2.81, 35.7$\pm$2.98) were significanty higher than those in zygote, 2-, 4-, 8-cell, compacted morula (29.8$\pm$3.21, 31.3$\pm$3.83, 29.3$\pm$3.58, 28.9$\pm$3.21 or 30.8$\pm$2.93). In experiment 3, the zygotes were exposed in VSl for 1, 2, and 3 min to the optimal exposed time. The cleavage rates (91.6, 88.5, 88.9%) and develop mental rates to blastocyst (83.3, 74.3 and 69.4%) depends on the exposed time in VSl were not significantly different among 1, 2, or 3 min, respectively. The cell number also were not significantly different among exposed time in VS1. respectively. These results indicate that OPP method could be useful for vitrification either EFS or EDS vitrification solution. The post-thaw survival rates at zygote were significantly lower than those at 2-, 4-, 8-cell, morula or blastocyst, respectively. The zygote stage were more sensitive rather than late stage embryos. The exposing time in VS1 for 1 min was better than that for 2 or 3 min, even it was not significantly different. The OPP vitrification method could be useful of mouse embryos either with EFS or EDS vitrification solution.