• Resources Recycling
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• v.27 no.4
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• pp.50-56
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• 2018

For the purpose of optimizing the counter current extraction process for separation of [Pr, Nd, Sm] group and [La] in mixed solution using Cyanex 572 as an extractant, the theory of Xu Guangxian was derived for calculating the optimized extraction factors. From the basic batch test result, the separation factor was 16.80 at extraction process and 21.48 at scrubbing process, and the loading capacity of 1.0 M Cyanex 572 was 0.12 M of rare earth element. The process parameters such as the stage number at extraction and scrubbing process, the flow rate ratio of feed and solvent solution can be calculated using an equation of optimum extraction ratio proposed by Xu Guangxian. From the result of calculation, 7 extraction stages and 4 scrubbing stages were required for rare earth separation, and the flow rate ratio of feed solution, solvent solution, scrubbing solution was 25 : 5.67 : 12.27.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.74-82
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• 2001

The effects of Al and Mn concentration on dry weight growth, nutrient status and gas exchange rates of 2-Year-old Japanese red pine(Pinus densiflora) seedlings grown in a nutrient culture solution were investigated. Al was added as aluminum chloride at 0, 10, 30 or 60ppm, and Mn was added as manganese chloride at 0, 30 or 60ppm to the nutrient culture solution. The pH of the solution was maintained at 4.0 by adding HCl or NaOH solution. The seedlings were transplanted into the nutrient culture solution, then they were grown in a greenhouse for 90 days. The interactive effects of Al and Mn on the dry weight growth of the seedlings were not significant. There were a main effect of Al or Mn on the dry weight growth and element concentrations of the seedlings. The treatment with Al of ${\geq}10ppm$ or that with Mn of 60ppm induced a significant reduction in the dry weight growth, which indicates that the effect of Al is stronger than that of Mn. The chlorophyll content of needles was not affected by Al treatment, but was significantly reduced by treatment with Mn of 60ppm. Furthermore, the treatment with Al of 60ppm or that with Mn of ${\geq}30ppm$ caused a significant reduction in the dark respiration rate of the roots. The net photosynthetic rate of the seedlings reduced with increasing the concentration of Al or Mn in the nutrient culture solution, which suggests that Al or Mn induced reductions in the relative growth rate(RGR) and net assimilation rate(NAR) of the seedlings were mainly due to the decrease of net photosynthesis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.853-859
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• 2007

This paper presents a microstrip patch array antenna having transmission feed and reception feed for satellite communication in the Ku band. In this paper, the element of the patch array antenna is a three-stacked structure consisting of one radiation patch and two parasitic patches for high gain and wide bandwidth characteristics. To obtain higher gain, the unit elements are expanded into a $1{\times}8$ may using a mixture of series and parallel feeds. The proposed antenna has horizontal polarization for the Rx band and vertical polarization for the Tx band. To verify the practicality of this antenna, we fabricated a three-stacked patch array antenna and measured its performance. The gain of the array antenna in the Rx and Tx bands exceeds 17 and 18 dBi, respectively. The impedance bandwidth is over 10 % in both bands. The cross-polarization level is below -25 dB, and the sidelobe level is below -9.4 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1642-1649
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• 2007

The lumped element isolators with temperature compensation magnetic circuits were designed in this paper. Isolators for mobile repeater at each band of K-PCS, GSM1900, W-CDMA, WiBro were fabricated by using optimum parameters of EM simulation, Form the results of this study, first of all, insertion loss at K-PCS band was below 0.2 dB and return loss was over 25dB. The bandwidth in isolation 23dB was found 30 MHz. Secondly, the figures of both losses at GSM1900 were 0.25dB and 23dB, respectively. The measured bandwidth in isolation 30dB was 60MHz. Thirdly, the losses at W-CDMA band were 0.15dB and 25dB. The bandwidth in isolation 24.8dB was found 60Mhz. Finally, the figures of both losses at Wibro band were 0.25dB and 23dB, respectively. The measured bandwidth in isolation 22.1dB was 100Mhz. In addition, the results of measured IMD were shown from 76.4dBc to 80.1dBc.

• Korean Journal of Comparative Education
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• v.23 no.5
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• pp.53-75
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• 2013

This article explores the impact of mergers on the experiences of students. A case design is used to gain an in-depth understanding of the students in a Korean university that was combined with a two-year college in 2007. Semi-structured interviews of 11 direct entrants, 5 transfer students, and 7 professors were conducted in 2010 for the data collection. The results suggest that mergers do not necessarily ensure the integration of the students involved. Since mergers pose enormous challenges to both transfer students and direct entrants, university leaders need to give careful attention to students' persistence and integration as the campus changes. The results also reveal that students' experience of mergers may be affected by cultural backgrounds as well as the hierarchical structure of higher education. In Korean society, where credentialism prevails, mergers can have different impacts on students who come from initial institutions of differing perceived quality, and thus mergers may incite tension among the students. In light of these concerns, this study's findings highlight the importance of student integration as a key element in mergers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.733-736
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• 2009

Power Line Communication(PLC) is need not additional communication line. So establishment expense is inexpensive and application is simple. Therefore, lower part network of various application field is possible. However, there are high subordinate interference and noise problem on limited transmission data and communication interference element. Wireless Sensor Network(WSN) is need not infrastructure, Self-regulating network architecture of sensor nodes is possible. So at short time, network construction is available. But, power consumption is increased by active sensing for QoS elevation and unnecessary information transmission, low electric power design and necessity of improve protocol are refered to life shortening problem and is studied. In this paper, supplement problem of power line communication and wireless sensor network mutually and because advantage becomes linkage integration control system using synergy effect of two technologies as more restriction be and tries to approach structurally control network that is improved for smooth network environment construction. Honeywell's hybrid sensor network does comparative analysis(benchmarking). Confirm performance elevation proposing teaming of power line communication and wireless sensor network. Through simulation, service delay decreases and confirms that performance elevation.

• Journal of The Korean Association of Information Education
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• v.25 no.4
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• pp.653-664
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• 2021

This study proposes a STEAM (Science, Technology, Engineering, Arts, and Mathematics) program for career exploration of middle school students. The proposed program utilizes VR (Virtual Reality) for new digital technology and webtoon as a popular cultural element. It enables the students to investigate promising fields and experience them virtually for themselves. We design the program based on the 2015 revised curriculum, which enhances the learning effects with existing subjects. In particular, the program provides a hybrid education to combine contact and untact classes considering the COVID-19 situation. The educational goal of the proposed program is to improve creativity and convergence capability. Specifically, it aims to prepare an educational foundation that integrates new digital technologies into education and applies the programs to school education fields. To prove the effectiveness of the developed program, we applied the program to the second graders of A middle school located in Seoul. We expect that the proposed program helps students learn how to utilize new digital technologies and explore future career paths.

• Journal of Information Technology Applications and Management
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• v.28 no.6
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• pp.69-85
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• 2021

In the era of the 4th Industrial Revolution, not only artificial intelligence, big data, robots, and biotechnology, but also cultural industries that require human creativity will lead. Among the cultural industries, the animation industry has high industrial utilization value due to its high connection with other industries. Among them, animation characters play the most important role as the subject leading the story of animation. In particular, the villain character not only serves as a medium for the main character to lead the story, but also captivates the audience with a different presence from the main character, adding to the fun and completeness of the animation. These characters consist of visual elements such as form and color, of which color is a tool that effectively conveys the character's personality and role to the audience, and is the first visual element to be considered in delicately describing the character's emotions and the relationship between characters. Therefore, this study attempts to analyze the color of the villain character. To this end, we will select eight Disney animations to derive the characteristics of the villain character's color by analyzing the color, value, chroma, and color association of the colors used in the Disney villain character. As a result of the analysis, the colors mainly used by Disney to convey the villain's image were red (R) and Orange (YR), and there was no difference depending on the times or animation production methods. Second, the brightness of Disney villain characters appeared to be the same medium/famous regardless of the times and production methods, and the frequency of use of high brightness was very low. In terms of saturation, the frequency of use of high and low saturation was high. Third, blackish (Bk), Strong (S), dull (Dl), and deep (Dp) tones were mainly used for tones. In particular, in recent 3D animations than previously produced 2D animations, the use of low chroma and the high black mixing rate increased. Fourth, it can be seen that Disney uses color as a visual method to more clearly express the psychology of the villain character using color association. In conclusion, the color selection of animation characters should be carefully considered as a tool to convey the character's personality, role, and emotion beyond simply using color, and the color selection of characters using color associations and symbols strengthens the narrative structure. It is hoped that this study will help analyze and select the character color of animation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.5
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• pp.279-286
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• 2021

In this study, we investigated the behavior characteristics of the L-type flange bolt connection, which is used to connect upper and lower flanges having L-type ring sections, by bolts. This connection is mainly used in domestic wind turbine structures, wherein it is a vital component as any imperfection could cause the collapse of the entire structural system. Therefore, understanding the behavior characteristics of the L-type flange bolt connection is imperative. In this study, the connection's response to external force was simulated using finite element (FE) analysis and the FE model was idealized to behave as a single L-type bolt flange. The variation in the bolt tension and the L-type flange stress were analyzed to understand the behavior characteristics of the connection. Moreover, the bolt-load function models proposed by Petersen, Schmidt/Neuper and VDI 2230, theoretically expressing a relation between bolt tension and external force, were compared to evaluate the suitability of the FE analysis and analyze the significant behavior characteristics of the connection. Furthermore, the changes in the bolt-load curve due to the variations in the partial dimensions of the L-type flange bolt connection were analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.12-19
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• 2021

Recently, with frequent earthquakes around the world, research on seismic design and seismic reinforcement of reinforced concrete facilities has been actively conducted from earthquakes. In particular, columns, which are compressed members of reinforced concrete structures, are vulnerable to lateral forces caused by earthquakes, so an appropriate seismic reinforcement method is required. Therefore, this study intended to develop Velcro seismic reinforcement method that is quick and easy to construct. For the development of Velcro seismic reinforcement, the adhesion and tensile strength of the existing industrial velcro was improved. A direct tensile test was also conducted to compare the tensile performance of the newly-developed velcro seismic reinforcement to industrial one. In addition, numerical analysis was performed to predict the seismic performance of RC columns reinforced by industrial and newly-developed velcro. Based on the analysis results, the strength and ductility of the non-seismic and velcro-reinforced RC column were reviewed. The analysis confirmed that both the strength and ductility of non-seismic RC columns reinforced by industrial and newly-developed velcro increased, but the seismic performance of the newly-developed Velcro reinforcement is better than that of industrial velcro.