• The Journal of the Convergence on Culture Technology
• /
• v.8 no.2
• /
• pp.349-354
• /
• 2022

This research was conducted in order to improve the hydrolysis resistance and mechanical properties of a resin compound and biodegradable mulching film, produced through the use of PBAT(Poly Butylene Adipate-co-Terephthalate) and PLA(Poly Lactic Acid). Various ratios of chain extenders and mechanical properties according to the annealing temperature conditions were investigated. The annealing process showed that compound resin can improve the crystallization capacity. In addition, incorporation of the chain extender was shown to improve and increase the tensile strength and hydrolysis resistance of the film. In the case of 0.6phr chain extender, the tensile strength was 383.0Kgf/cm², which was improved by 155% compared to the control films. When the blow up ratio(BUR) was 2.5, the optimal tensile strength of the film increased greatly, expanding up to 379.0/195.2kgf/cm² in the both machine direction (MD) and transverse direction (TD).

• Journal of the Korean Applied Science and Technology
• /
• v.39 no.5
• /
• pp.632-643
• /
• 2022

Although probiotics have been shown to improve health when consumed, recent studies have reported that they can cause unwanted side effects due to bacterial-human interactions. Therefore, the importance of prebiotics that can form beneficial microbiome in the gut has been emphasized. This study isolated and identified bacteria capable of producing biopoymer as a candidate prebiotic from traditional fermented foods. The isolated and identified strain was named WCYSK01 (Wissella sp. strain YSK01). The composition of the medium for culturing this strain was prepared by dissolving 3 g K₂HPO₄, 0.2 g MgSO₄, 0.05 g CaCl₂, 0.1 g NaCl in 1 L of distilled water. The LMBP(low molecular weight biopoymers) produced when fermentation was performed with sucrose and maltose as substrates were mainly consisted of DP3 (degree of polymer; isomaltotriose), DP4 (isomaltotetraose), DP5 (isomaltopentaose), and DP6 (isomaltoheptaose). The optimization of LMBP (low molecular weight of biopolymer) production was performed using the response surface methodology. The fermentation process temperature range of 18 to 32℃, the fermentation medium pH in the range of 5.1 to 7.9. The yield of LMBP production by the strain was found to be significantly affected by q fermentation temperature and pH. The optimal fermentation conditions were found at the normal point, and the production yield was more than 75% at pH 7.5 and temperature of 23℃.

• Journal of Korean Society for Quality Management
• /
• v.50 no.3
• /
• pp.473-490
• /
• 2022

Purpose: The purpose of this study is to propose a new useful suggestion to monitor the stability of process by developing a stability ratio or index related to investigating how well the process is controlled or operated to the specified target. Methods: The proposed method to monitor the stability of process is building up a new measure index which is making up for the weakness of the existing index in terms of short or long term period of production. This new index is a combined one considering both stability and capability of process to the specification limits. We suppose that both process mean and process variation(or deviation) are changing on time period. Results: The results of this study are as follows: regarding the stability of process as well as capability of process, it was shown that two indices, called SI(stability index) and PI(performance index), can be expressed in two-dimensional X-Y graph simultaneously. This graph is categorized as 4 separated partitions, which are characterized by its numerical value intervals of SI and PI which are evaluated by test statistics. Conclusion: The new revised index is more robust than the existing one in investigating the stability of process in terms of short and long period of production, even in case both process mean and variation are changing.

• The Journal of the Korea Contents Association
• /
• v.22 no.3
• /
• pp.54-61
• /
• 2022

Ship is a huge system including a variety of pipe arrangements. Pipes are installed according to the design layout, however the end poistion of pipes are not well matched owing to its measurement and construction errors. In this situation, the customized pipe fitting is frequently designed to connect with both pipes, the position of which are manually measured. This paper focused that these two coordinates are measured by point cloud from RGBD sensor and the relative transformation induced by positional and orientational differences is calculated by inverse kinematics in robotics theory. Therefore, the result applies for the methodology of the pipe connection design. The pipe coordinate that is estimated by the matching and the probabilistic RANSAC method will be verified by experiments. The kinematic design parameters are computationally calculated by using the minimum degree of freedom that connects both pipe coordinates.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.6
• /
• pp.1699-1708
• /
• 2021

Response surface methodology was applied to determine the optimum extract conditions(extract temperature and time) for the high-quality Agakong beverage. The optimal roasting condition for Agakong was set at 250 ℃ for 30 minutes. As quality criteria of Agakong, pH, color values and isofavone contents with extract temperature and extract time, the probability value (p<0.01) demonstrated a high significance for the regression model. It was found that the higher the extraction temperature and the longer the extraction time, the higher the isoflavones content. The optimized conditions of extraction isoflavones from agakong were found to be optimized ratio of extraction temperature 99.5℃, extraction time 1.7 h and the maximum rutin yield was 10.63 ㎍/mL.

• Journal of Aerospace System Engineering
• /
• v.17 no.4
• /
• pp.58-66
• /
• 2023

The latest global issues are the Space economy and low-orbit Space communication. 3GPP announced Release 17 standardization in June 2022, and in this regard, the United States prepared a strategy to enhance the competitiveness of the low-orbit 5G-NTN Space industry, and create an ecosystem at the national level in March 2023. Global smartphone semiconductor manufacturers have announced the development and verification results of standard-based chip technology, and satellite communication operators are launching low-orbit 5G-NTN Space communication services and rate products through convergence between terrestrial communication networks. This study diagnoses the current status of Korea's low-orbit 5G-NTN space communication ecosystem. We present our ecosystem creation strategy in terms of fair competition in the market, the service legal system, and the national R&D governance system.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.31 no.3
• /
• pp.65-71
• /
• 2023

Cesium discharged from nuclear power plants requires technology for safely treating, due to its harmfulness to the human body. In this work, activated carbon impregnated with triethylenediamine (TEDA) process was applied to effectively remove cesium dissolved in aqueous solution. The surfaces on the activated carbon were chemically modified with various TEDA concentrations (2.5, 5.0, 7.5, 10.0, and 12.5%) and the optimal TEDA concentration was obtained to be 5.0% by the assessment for cesium removal efficiency. In addition, when 5.0% TEDA-impregnated activated carbon was used to treat 5.0 and 10.0 mg/L of cesium, the removal efficiency was 71.5% and 61.1%, respectively. Also, it was found to be the chemical adsorption from the adsorption kinetics experiment by temperature change. A novel remediation technology developed in this study could be practically employed for removing cesium contained in surface and ground water.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.1
• /
• pp.191-197
• /
• 2023

The purpose of the study was to provide an educational environment for designing and producing virtual reality practice contents that can be used in semiconductor production lines and clean rooms. Through this process, the user can acquire practical knowledge through experiences close to reality, such as experiencing the main semiconductor solar cell manufacturing facilities as well as procedural knowledge before and after entering the clean room.. In particular, it provides users with an immersion experience close to reality by creating an environment for experiential content necessary for semiconductor and solar cell manufacturing processes and clean room entrance procedure experiential content, which is expected to improve education immersion, realism, cost, efficiency, and education satisfaction. Depending on the characteristics of Dangerous, Impossible, Counter-productive etc, immersive content makes learners immersed in the learning content, induces proactive/active learning, and embodies the learning content, resulting in positive results in the field of improving educational effectiveness.

• Journal of the Korean Institute of Gas
• /
• v.27 no.1
• /
• pp.1-12
• /
• 2023

Coal gasification is a process of incomplete coal combustion to produce a syngas composed of hydrogen and carbon monoxide. It is one of methods to utilize coal cleanly because the process does not emits nitrogen oxides or sulfur oxides and particulate matters. In addition, chemicals can be produced using syngas. Coal gasification is classified as IGCC (Integrated Gasification Combined Cycle), Plasma coal gasification and UCG (Underground Coal Gasification). Recently, WGS (Water Gas Shift) reactor and carbon capture system have been combined to gasifier to produce hydrogen from coal. In this study, the coal gasification and method of hydrogen production from syngas was summarized, and the hydrogen production from coal gasification project was investigated.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.3
• /
• pp.457-462
• /
• 2022

This study is about the case applied of a shallow foundation reinforcement method for a low/mid-rise building where a relatively small load is applied by using a soil stabilized material that utilizes recycled resources. First, laboratory mixing test was conducted for four mixing ratios in order to derive the optimal mixing ratio in the field. Using the derived optimal mixing ratio, it was applied as a shallow foundation for the building in the field. The field application method used a simple process of compaction by the soil mixedure with the original soil and the soil stabilized material in the field. After field application, a plate bearing test was performed on one original ground and two improved ground to confirm the allowable bearing capacity. As a result of checking the bearing capacity, it was found that sufficient bearing capacity was exhibited.Therefore, it was confirmed that it can be used as a shallow foundation for the building.