• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.681-693
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• 2019

Multi-use ophthalmic solutions are used many times after opening; therefore, there is a high possibility of decreased quality during use. This study was conducted to determine the recommended use period of multi-use ophthalmic solutions based on evaluation of the stability by comparing stability evaluation regulations of the USA, EU and Korea We selected four types of multi-use ophthalmic solutions (Olopatadine (Olo), Fluorometholone (Flu), Dorzolamide (Dor), Timolol (Timol)) that are frequently marketed in Korea and evaluated their stability during storage according to the actual usage method after opening. The Olo had a decrease in assay and preservative content at 2 months after opening, while Flu showed a significant difference from day 28 after opening. For Dor, significant differences were observed from day 14 after opening in the assay and impurity test item and Timol showed a significant difference from day 28 after opening. Based on the results of the stability test Olo and Flu should only be used within 28 days of opening, while Dor and Timol should be used within 14 days of opening. Therefore, we suggest that regulations system related use periods of multi-use ophthalmic solutions designed as aseptic preparations should be improved based on the results of stability tests after opening.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.201-206
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• 2019

This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide ($Ga_2O_3$) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating ${\beta}-Ga_2O_3$ (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of $10{\times}15mm^2$. Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length ($L_g$) of $2{\mu}m$ and a gate-drain spacing ($L_{gd}$) of $5{\mu}m$. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for $V_{gs}<-6V$, and the three-terminal off-state breakdown voltage was over 482 V in a $L_{gd}=5{\mu}m$ device measured in Fluorinert ambient at $V_{gs}=-10V$. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately $5.3{\times}10^5$. These device characteristics indicate the promising potential of $Ga_2O_3$-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.

• Clean Technology
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• v.25 no.1
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• pp.33-39
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• 2019

A.C (activated carbon) is mainly used to remove VOCs (volatile organic compounds), however, it has many problems such as fire risk due to increasing of adsorbent surface temperature during VOCs ad/desorption, increased cost by frequent replacement cycles requirement and performance degradation when containing moisture. In order to solve these problems, many researches, hydrophobic zeolite adsorbents, have been reported. In this study, $NH_4{^+}Y$-zeolite was synthesized with Y-zeolite through steam treatment and acid treatment, which is one of the hydrophobic modification methods, to secure high surface area, thermal stability and humidity resistance. The Y, Y-550-HN, Y-600-HN and Y-650-HN had adsorption capacities of $23mg\;g^{-1}$, $38mg\;g^{-1}$, $77mg\;g^{-1}$, $61mg\;g^{-1}$. The change of Si/Al ratio, which is an index to confirm the degree of modification, was confirmed by XRF (X-ray fluorescence spectrometer) analysis. As a result, the adsorbtion performance was improved when Y-zeolite modified, and the Si/Al ratio of Y, Y-550-HN, Y-600-HN, Y-650-HN were increased to 3.1765, 6.6706, 7.3079, and 7.4635, respectively. Whereas it was confirmed that structural crystallization due to high heat treatment temperature affected performance degradation. Therefore, there is an optimal heat treatment temperature of Y-zeolite, optimum modification condition study could be a substitute for activated carbon as a condition for producing an adsorbent having high durability and stability.

• The Journal of the Korea Contents Association
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• v.19 no.4
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• pp.490-501
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• 2019

This study is aimed at researching Gyobang Dance performed by gisaeng of Gyobang in the banquet of Tonshinsa in Yeongnam Jwa-do Province. For this study, Hae-haeng-chong-che, a collection of 28 travel essays written by Joseon Tonshinsa after visiting Japan, and a collection of literary works were analyzed. Joseon Tonshinsa used Yeongnam Jwa-do Province as a route to Japan in obedience to a royal command, and Yeongnam U-do Province as a way back to Hanyang after completing their missions. The country gave a huge banquet to relieve Tonshinsa's anxiety about the voyage and to pray for a safe trip. The banquets were concentrated in Yeongnam Jwa-do Province, the way down to Busan departing from Hanyang. Looking into Tonshinsa's records, it can be seen that Tonshinsa banquets took place in Andong, Yeongcheon, Gyeongju, Milyang, and Busan. Gyobang Dance performed at Tonshinsa banquets includes Geommu, Hwangchangmu, Cheoyongmu, Cheondo, Mudong, Ipchum, and Jungchum. Through Tonshinsa envoy, 'Jeseon Tonshinsa-gil' was formed in Yeongnam Jwa-do Province, and through Tonshinsa banquets, the artistry of Gyobang Dance was compiled. Nevertheless, present Yeongnam Jwa-do Province has remarkably less Gyobang Dance passed down in comparison to Yeongnam U-do Province. For this reason, there is a need to look into Gyobang Dance of Yeongnam Jwa-do Province. The purpose of this study is to closely examine the cultural and artistic characteristics of Gyobang Dance performed at Tonshinsa banquets in Yeongnam Jwa-do Province formed through Joseon Tonshinsa-gil.

• The Journal of the Petrological Society of Korea
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• v.27 no.4
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• pp.195-205
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• 2018

Noerok is a green pigment made of mineral used the Gachil(priming coat) of wooden architecture in Chosun Dynasty era. It has been reported that various Noerok are discovered in Janggimyeon, Pohang. In this study, The Noerok from two places is compared and discussed. Noerok in the two places has blulsh-green to green color, and it is similar to their occurrences on fracture filling, vein and dike on outcrop. However, there are differences between two sites according to its petrological feature, mineral composition and geochemistry. While the Noeseongsan sample is mostly celadonite, Gwangjeongsan samples are characterized by celadonite with varying contents of cristobalite, tridymite, feldspar, along with some vitrified contents. In terms of major elements, the amount of $Al_2O_3$, $Fe_2O_3$, MgO and $K_2O$ decreases linearly with increasing $SiO_2$, whereas $Fe_2O_3$ is linearly proportional to MgO. In summary, Noerok in the study areas can be classified into 4 types (type 1, type 2, type 3-1, type 3-2) base on color, mineral composition, elemental composition, and vitrification grade.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.513-519
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• 2019

Typically, contaminated sediments cause clogging of the drain pipe, which increases the residual water pressure in the drain pipe; this study constructed a system for improving drainage efficiency of tunnels by reducing physical and chemical obstructions through ultrasonic energy generated by a PVDF film. The developed hybrid drainage system utilized a PVDF material film fused with an existing drainage tunnel and maintenance system resulting in the ability to initialize the reverse piezoelectric effect, which was evaluated through an on site application. In order to investigate the maintenance performance of the tunnel drainage system, contaminated sediments were simulated in a drainage pipe to test the effect of ultrasonic conditions on drainage efficiency in the laboratory. As a result of applying the developed portable equipment, the ultrasonic energy was generated for about 20 minutes resulting in a reduction of 74.62% of the contaminated sediments and improving drainage efficiency. From the tunnel, acoustic pressure measurements were taken to calculate the response rate while taking into account the laboratory results. In addition, PVDF film was attached to the transverse and longitudinal side of the drainage pipes where contaminated sediments occur most often in the field tunnel. these calculations show contaminant removal was 90% effective.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.259-266
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• 2019

This study aimed to identify factors that had an influence on preventive behaviors of Emergency Medical Service students against tuberculosis to promote their preventive behavior. The subjects of the study were 314 students studying emergency medical service from one 4-year college and two 3-year colleges in Jeollabukdo and they were researched with the use of a questionnaire from June 25, to July 6, 2018. For a statistical analysis of the data obtained, this study used SPSS 18.0 and conducted a t-test, an ANOVA, a Pearson's correlation coefficient and a multi-regression test to analyze the data. Pearson's correlation coefficient analysis showed that the preventive behavior levels was significantly correlated with knowledge of tuberculosis (r = 0.268, p <0.001) and attitude (r = 0.394, p<0.001). As results of the multi-regression test, the higher the knowledge of tuberculosis(${\beta}=0.152$, p<0.001) and the higher the attitude(${\beta}=0.052$, p<0.001), the higher the preventive behavior levels. In addition, Students who have experienced tuberculosis in their own or relative's relatives have a high level of prevention behavior(${\beta}=-0.186$, p=0.001). Therefore, it is suggested that organized and consistent education programs to promote knowledge on tuberculosis, change negative perception on it and improve preventive behavior levels should be developed and provided.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.636-641
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• 2018

This study was conducted to compare the stability between branched-chain amino acid (BCAA)-encapsulated liposome and double emulsion (DE). Liposome was produced by high-speed homogenization and ultrasonication whereas DE was prepared by homogenizing with surfactants. All samples were fixed at pH 4 and 7 and stored at 4, 25, and $40^{\circ}C$ for 5 days. Encapsulation efficiency and cumulative release rate were measured under $4^{\circ}C$ and at $25^{\circ}C$. The results showed that the size of BCAA-coated liposome was greater at pH 7 than at pH 4. The zeta-potential value of BCAA-coated liposome was greater at pH 4 than at pH 7. It was supposed that the negatively charged liposomes attracted the positively charged BCAAs at pH 4 resulting in the formation of the vesicle with smaller size. Particle size of DE was smaller than $100{\mu}m$. Encapsulation efficiencies of BCAA in DE or liposome were over 97%, approximately, and the cumulative release rates of them were below 30% for 5 days.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.182-190
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• 2018

Many pharmaceutical companies operate the SFA system to support salespeople. The SFA system is used for various behaviors of salespeople. However, there is a lack of empirical analysis on the performance of SFA in Korea. The purpose of this study is to investigate the utilization of SFA system and the non - financial performance of SFA system. The subjects of the survey were 347 pharmaceutical community members who consisted of pharmaceutical salespeople and surveyed online for 18 days from March 13, 2018 to April 30, 2018. and the effective response rate was 23.1% (80/347). The analysis shows that the higher the level of SFA system utilization, the higher the non - financial performance. By type of company, the utilization level of multinational companies was higher than that of domestic companies. Among the SFA utilization level items, 1.47 points (3.65, 2.18) were higher than the domestic companies in terms of the support service items. Among the SFA performance items, foreign companies were 1.47 points (3.16, 1.69) Respectively. This suggests that the SFA development and operation method of the domestic company focuses on the management service rather than the support service for the salesperson and the customer satisfaction. Through this study, it is considered that domestic companies should strengthen sales person support and customer satisfaction information providing function when operating SFA system.

• Journal of Korea Water Resources Association
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• v.51 no.12
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• pp.1171-1180
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• 2018

Korea's water transmission system is operated by the nonpressure flow method that flows from highlands to lowlands due to the nature of Korea with many mountainous areas. In order to store water in the highlands, the water pumps are installed and operated. However, In this process, a lot of electrical energy is consumed. therefore, it is necessary to minimize the energy consumption by optimizing the size and operation schedule of the water pumps. The optimal capacity and operation method of the water pump are affected by the size of the tank (distributing reservoir). Therefore, in order to economically design and operate the water transmission system, it is reasonable to consider both the construction cost of the water pump and the tank and the long-term operation cost of the water pump at the step of determining the scale of the initial facilities. In this study, the optimum design model was developed that can optimize both the optimal size of the water pump and the tank and the operation scheduling of the water pump by using the genetic algorithm (GA). The developed model was verified by applying it to the water transmission systems operated in Korea. It is expected that this study will help to estimate the optimal size of the water pump and the tank in the initial design of the water transmission system.