• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.2
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• pp.166-174
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• 2009

The liquid column trajectory and column breakup length characteristics have been experimentally studied in angled jets injected into subsonic crossflow. Pulsed shadowgraph photography and Planar Liquid Laser Induced Fluorescence measurements were used to determine the angled effects. And the main objectives of this research are to get a empirical formula of liquid column trajectory and breakup length with below the $90^{\circ}$ degree injection angle conditions, and were compared with previous results. It was also found that the empirical formula, which reversed injection conditions of air stream. As the result, This has been shown that liquid column trajectories and column breakup length were spatially dependent on various injection angle, normalized injector exit diameter, air-stream and fuel injection velocity. Furthermore, the empirical formula of liquid column trajectories and breakup length has been some different of drag coefficient results between normal angled injection and reversed injection in subsonic crossflow.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.2
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• pp.205-211
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• 2014

The design parameters to affect the cooling capacity of a cryocooler were examined with the application of numerical modeling to optimize an inertance pulse tube cryocooler. This modeling includes the regenerator, pulse tube, inertance tube, gas reservoir, and heat exchangers. One-dimensional modeling on strings of acoustic and thermoacoustic elements was applied to compare the design parameters. The diameter and length of the pulse tube can significantly affect the cooling capacity and efficiency. The aftercooler was optimized by maintaining a certain size. The efficiency also improved as the length of inertance tube and volume of gas reservoir are increased. It was confirmed that effective design parameters are critical to the performance of an inertance pulse tube cryocooler considering the comparison of the dimensions of each part to optimize its cooling power and efficiency.

• The korean journal of orthodontics
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• v.11 no.2
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• pp.77-83
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• 1981

The author analyzed the morphological pattern of mandibles and lower third molars in order to study and predict the impaction of the developmental third molars. The subjects consisted of 37 males and 87 females with malocclusion. The following results were obtained: 1. The mandible was shown to be shorter in the impacted third molar group than in the erupted group, both in over-all length and in body length. 2. The developmental mesial angulation of the third molar to the mandibular plane was higher in the impacted third molar group. 3. There was a tendency for impacted third molars to be slightly larger than those which erupted except Class II malocclusion in female. 4. In the available space for the eruption of the third molar, significant space deficiency was found in association with the impacted third molar group compared with the erupted group.

• Journal of Korean Association for Spatial Structures
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• v.16 no.4
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• pp.125-132
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• 2016

This paper is a study on the nonlinear behavior of polyhedron curved space roof as building structures of quasicrystal system. The quasicrystal is made up of two kinds of parallel hexahedrons, and all the line elements of the parallelepiped have the same length. The quasicrystal design grid dome has a pentagonal symmetry and all members have the same length. This paper described form of design gird dome, and showed the analysis conditions. Also, The displacement-load curve is shown through the analysis and we grasped the flow of the load and forces through analysis of design grid dome applied quasicrystal system.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.360-363
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• 1999

Video data compression is a major key technology in the field of multimedia applications. Variable-length coding is the most popular data compression technique which has been used in many data compression standards, such as JPEG, MPEG and image data compression standards, etc. In this paper, we present memory efficient VLC decoder architecture for MPEG-2 application which can achieve small memory space and higher throughput. To reduce the memory size, we propose a new grouping, remainder generation method and merged lookup table (LUT) for variable length decoders (VLD's). In the MPEG-2, the discrete cosine transform (DCT) coefficient table zero and one are mapped onto one memory whose space requirement has been minimized by using efficient memory mapping strategy The proposed memory size is only 256 words in spite of mapping two DCT coefficient tables.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.91-97
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• 1995

Cyclic tests were performed with dowel joints which are being widely used for furniture manufacturing in Korea. In this study, effects of various factors-such as species of joint members, diameter and length of dowels, and space between dowels-on stiffness, strength and damping ratio of joints were evaluated and concluded as follows: 1. Under cyclic loads, failure of dowel joints were caused by bending failure of dowels. 2. Dowel joints were evaluated to be stiff but general load carrying capacities were relatively low. 3. Joint moduli and damping ratios of dowel joints decreased as diameter and length of dowels, and space between dowels increased. 4. In dowel joints, properties of dowel itself have greater effects on stiffness and strength of joints than properties of joint members.

• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.2
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• pp.22-31
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• 2000

This study aimed at investigating the influence of tunnel length and area, drag coefficient, train velocity on the characteristics of ventilation in railway tunnel. The modified Subway Environment Simulation(SES) computer program has been used to calculate the flow velocity and longitudinal emission concentration with various condition. According to a series of numerical simulation, the influence of various parameter on maximum air flow velocity, purging length and emission concentration are estimated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.8
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• pp.79-86
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• 2006

Swirl injector with adjustable backhole length was analyzed to suppress high-frequency combustion instability in Liquid Rocket Engines. In order to analyze the effect of variable backhole injector as an acoustic absorber, backhole injector was regarded as a quarter-wave resonator. As a result of theoretical approaches and acoustic tests, backhole injector with adjustable length could decrease the unstable modes of combustion chamber. And the damping efficiency was estimated by measuring damping rates experimentally.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1060-1069
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• 1998

Electrical properties such as space charge accumulation and water tree length and physical properties such as tensile strength, elongation and degree of crosslinked polyethylene (XLPE)/ethylene n-butyl acrylate copolymer (EnBA) blends were investigated. It was found that electrical properties such as water tree length grown at a specific condition and AC breakdown strength are improved by blending the XLPE with EnBA. The EnBA having higher nBA content showed the better electrical properties in XLPE/EnBA blends. A further improvement of these properties was achieved when a small amount of crosslinking coagent was used in the preparation of XLPE/EnBA blends.

• Acta Via Serica
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• v.3 no.2
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• pp.1-22
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• 2018

The concept of the "Seidenstrassen" (Silk Road) was created by the German geographer F. von Richthofen (1833-1905) in 1877. The "Seidenstrassen" means communication between China and the Roman cultural area. To prove the route of dissemination of silk, Richthofen not only focused on geographical substantiality, based on the routes of the Chinese Zhang Qian and the Roman Ptolemy, but also on etymological, historical, and religious sources. In fact, his Silk Road concept has the trade of silk as well as the humanistic ideas of cultural exchange. It is worth noting that in his book China, Richthofen presented the Silk Road as a space-time concept that considers the length of space as well as the length of time by highlighting humanistic examples that came into modern times through the Sea Route. Later, the English term "Silk Road" appeared in 1938, the Japanese term "シルクロ-ド" (sirukurodo) in 1939, and the Korean term "실크로드" (silkrodeu) in 1952.