• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.833-837
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• 2010

This study aims at finding an optimal exhaust diffuser design of a high altitude testing chamber for a low bypass turbofan engine (F404-402) with thrust pound force of 17,700 and air mass flow rate of 66kg/s ejecting at a speed of Mach 1.66. The final proposed ejector size has better pressure recovery characteristics and targets to reduce operational cost at engine performance testing. Conventional high altitude test chamber layout was adopted and first drawn in two dimensions using Autocad software so as to determine the gas path, the ejector frontal size was then determined from gas dynamics equations considering traditional gas ejection method where both the engine exhaust and cell cooling air are exhausted via the ejector. Modification to a smaller ejector with an alternative secondary cell cooling exhaust port was then performed and modelled in 3D using Solid Works software.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.6
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• pp.380-385
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• 2016

Thermal characteristics of 20 W LED module on light thermal conductive plastic (TCP) heat sink were investigated in comparison with that on aluminum die casting alloy (ADC-12). Thermal simulations of the heat sinks were conducted by using flow simulation of SolidWorks with the following input parameters: density is 1.70 and $2.82kg/m^2$, thermal conductivity is 20 and $92W/(m{\cdot}K)$ for TCP and ADC-12, respectively. The simulated and measured temperatures of the LED modules on TCP heat sink were consistent with its measured temperature, which was $3^{\circ}C$ higher that on ADC-12. The fabricated LED module on TCP heat sink with a weight of 120.5 g was 30% lighter in weight than that of the ADC-12 reference with 171.0 g.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.08a
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• pp.70-71
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• 2002

Exchange-coupled cluster of transition-metal ions are relevant to many different scientific areas, ranging from chemistry to solid-state physics, biology, material science and has been the subject of much research in recent years(1,2). Single crystal EPR spectroscopy works as a very effective tool for the measurement of J values for small exchange interactions. This makes EPR technique very suitable for detection of weak exchange coupling transmitted over long distances via extended atomic and melecular bridges. Large polyoxometallates (3) may provide ideal structural environments for the study of interactions between paramagnetic ions. The detailed nature of magnetic interaction (positive sign and magnitude of J~0.006 $cm^{-1}$ /) was clearly determined for di-copper(II) system by single crystal EPR spectroscopy (4). The single-triplet (S-T) transitions are forbidden by different symmetries of the wave functions. However, when the singlet ground state is mixed into triplet states, the S-T transitions can be allowed and observed as weak lines. These weak S-T lines are positioned symmetrically with respect to the main transitions in the distance equals to 2J from the center of the spectrum. This lines allow one to determine the J-value with very high accuracy when │J│ ＜ hv 0.32 $cm^{-1}$ /. Unfortunately, the S-T transitions in the single crystal were detected by EPR method only in a few complexes until now. We have measured single-triplet transition lines for several magnetically coupled cluster systems and determined their J values accurately. The temperature dependency of J was studied by monitoring the changes in S-T.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.29-35
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• 2014

Plate heat exchanger are being applied in the field of OTEC (ocean thermal energy conversion) and SWAC (seawater air conditioning) system. This study is to analyze numerically the heat transfer and pressure drop characteristics by using solid works flow simulation in order to offer optimum design data of plate heat exchanger. Plater heat exchanger proposed in this study is four types. The geometric design parameters of plate heat exchanger are a channel space, a flow orientation, a plate array, the flowrate of working fluid and so on. The main results for numerical analysis of plate heat exchangers are summarized as follows. Heat transfer performance for the channel space of 2.4 mm shows the highest value compared to other spaces. And, the Type 4 plate heat exchanger in Table 2 is the highest performance. From the pressure drop characteristics of plate heat exchanger, the channel space of 3.2 mm shows the lowest value. And Type 1 plate heat exchanger in Table 2 is the lowest pressure drop.

• Journal of the Korean Society for Library and Information Science
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• v.53 no.4
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• pp.189-211
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• 2019

The purpose of this study was to establish the concept of theme collection in the library, to clarify the reality of the theme collection operation. This study was to set up methodology for constructing and operating the theme collection in the future and to provide implications for future development. For this purpose, this study conducted in-depth interviews with a total of 12 directors and librarians from four public libraries. The results of the analysis revealed that the theme collection can be built and function properly with a solid understanding of its collection, users and community, and sharing its services goals and orientations. In addition, it was found that the task of constructing a theme collection contributes to the establishment of the identity of the librarian, and it is interrelated with the various library works. Finally, a comprehensive model of current theme collections was discussed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.664-670
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• 2018

In modern society, CCTV, which is the eye of surveillance, is being used to collect image data in various ways in daily life. CCTV is used not only for security, surveillance, and crime prevention but also in many fields such as automobile and black box. In this paper, we have developed a STM32F407 ARM chip based camera system for various applications. In order to develop camera system, modeling of camera system based on 3D structure was carried out in SolidWorks environment. The PCB board design was developed to extract the PCB parts from the camera system modeling files into iges files, convert them from the Altium Designer tool into 3D and 2D boards, After designing the camera system circuit and PCB, we have been studying the implementation of the stable system by using TRM (Thermal Risk Management) tool to cope with the heat simulation generated on the board.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.106-106
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• 2019

Human needs energy to maintain metabolisms, and these energy sources were uptake foods or nutritions. The most effective source was known for glucose among the nutrients, furthermore the glucose is an important source of energy for blood cells and control brain maintenences cells. But as food is plentiful and eating habits become more westernized, fast food and irregular meal times by works. Nowadays, diabetes were rapidly increased by malnutriton and obesity. Diabetes was the sixth highest on the list of causes of death in Korea, released by the Statistics Korea in 2015, which is considered a serious social problem for adult diseases. Therefore, this study aims to establish the optimal hot water extraction conditions of mixed herbs extract mixture compounds that are effective in diabetes. The independent factors were extraction temperature (X1: $40-120^{\circ}C$), extraction time (X2: 2-10 hrs.), and the ratio of water to sample (X3: 40-200 mg/mL). Their effects were assessed on dependent variables of the extract properties, which included soluble solid contents, Brix of sample extract, total polyphenols content, total flavonoids content and DPPH Radical scavenging activity. As a result, the content of total polyphenol content was the highest in No.12(6 hrs, $120^{\circ}C$, 67 mg/mL) and the highest total flavonoid contents was found in No.16(6 hrs, $80^{\circ}C$, 40 mg/mL). DPPH Radical scavenging activity showed the highest activity in No.7(8 hrs, $100^{\circ}C$, 100 mg/mL).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.9-16
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• 2019

In the present study, to investigate flows around space launch vehicles at mid-high altitudes efficiently, a three-dimensional unstructured mesh Navier-Stokes solver employing a Maxwell slip boundary condition was developed. Validation of the present flow solver was made for a blunted cone-tip configuration by comparing the results with those of the DSMC simulation and experiment. It was found that the present flow solver works well by capturing the velocity slip and the temperature jump on the solid surface more efficiently than the DSMC simulation. Flow simulations of space launch vehicles were conducted by using the flow solver. Mach number of 6 at the mid-high altitude around 86km was considered, and the flow phenomena at the mid-high altitude was discussed.

• Journal of the Korea Convergence Society
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• v.10 no.4
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• pp.189-194
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• 2019

This thesis aimed to apply the 3D-printing technology rapidly introduced to the overall industry to jewelry design. In the results of examining preceding researches, out of 3D-printing methods, the FMD method was used the most in design area. However, for jewelry design, the 3D-printing is used for casting process out of production processes, so that the printing method is not FMD, but DLP. Thus, the researcher examined the material functions and applicability of jewelry design through research works, by applying the 3D-printing in DLP method to jewelry design. In the results, brooches were completed by applying the 3D-printing to the jewelry design with no casting process, and then utilizing enamel and pure silver together. Producing light and solid completed products in various colors, they were verified as applicable materials. Also, as the size and form of curved design mainly used for non-geometric jewelry design could be accurately predicted through Rhino CAD, diverse possibilities of advancement to be easily used for the development of formative form of jewelry design in the future were revealed.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.323-337
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• 2021

This study will attempt to analyze media art and discuss its main characteristics by using the concept based on Relational Aesthetics 'Affective Turn' as a basis of the theory. In addition, this study has some theoretical and practical implications, both in terms of the research and analysis of artworks and the structure development of art theories and aesthetics. To conduct the research, I have gone through a literature review on previous studies related to media art and Relational Aesthetics. Then, I have conducted a case study on the media art of TeamLab. This study shows that from the perspective of Relational Aesthetics, media art shows unique characteristics such as borderless and shareability. Moreover, it can allow the audience to actually 'feel' the relationship and integration between various objects. I hopethat this research could be used as a solid basis for future research and helpstrengthen the interaction between modern art and the public.