• Composites Research
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• v.14 no.1
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• pp.1-7
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• 2001

In this study, damage evaluation of glass fiber reinforced thermoplastic composites was investigated with acoustic emission method. Specimens of 1.7mm thickness laminate were made from PET and 7 layers o171ass fabrics. Notch and impact loading were added to the specimen and normal tensile test and tensile test with the dead load were carried out. AE signal was measured as the functions of notch ratio to the width0 and impact energy in order to find out the correlation between fracture mode and AE parameters. The result has shown that low amplitude of AE signal was due to the microcrack of matrix and its growth, whereas the amplitude in the mid range was the response to the delamination and interfacial separation. In the range of high amplitude above 90dB. the fracture of glass fabric was found. Tensile strength decreased with increasing notch ratio to the width and impact energy because of tile effect or delamination, the cracking of matrix and stress concentration. In proportion to the size of damaged area. AE signal showed its wider range of frequency and energy as well as increased number of hits.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.523-532
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• 2013

When the golf club hits the ground prior to making contact with the golf ball, we define it as 'fat shot'. The aim of this research was to investigate the difference between normal shot and fat shot in golf. Five candidates playing as recreational golfer participated in this research and they were all right-handed people. Time phase between each event, wrist cocking angle, elbow extension-flexion angle, backswing height, pelvis angle, thorax angle, L-GRF, R-GRF, pelvis linear velocity, pelvis angular velocity and COG path were calculated. For statistical analysis the paired T-test was used. An early un-cocking, an early right elbow extension and impact with leaving their weight behind foot were not reasons of fat shot. Backswing height, X-Factor, pelvis angle and thorax rotation angle were not different between normal shot and fat shot. But we could find a pattern of abrupt pelvic movement and weight shift to target direction just before impact in case of fat shot. In addition fat shot showed time-delayed and small value of pelvis linear velocity pattern to upward during downswing phase as against normal shot.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.93-97
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• 2005

Air interlacing serves to protect the yarn against damage, strengthens inter-filament compactness or cohesion, and ensures fabric consistency. The air interlacing nozzle is used to introduce intermittent nips to a filament yarn so as to improve its performance in textile processing. This study investigates the effect of interlacing nozzle geometry on the interlacing process. The geometries of interlacing nozzles with multiple air inlets located across the width of a yarn channels are investigated. The basic interlacing nozzle is the yarn channel, with a perpendicular single air inlet in the middle. The yarn channel shapes are cross sections with semicircular or rectangular shapes. This paper presents three doubled sub air inlets with main air inlet and one of them is slightly inclined doubled sub air inlets with main air inlet. The compressed air coming out from the inlet hits the opposing wall of the yarn channel, divides into two branches, flows trough the top side of yarn channel, joins with the compressed air coming out from the sub air inlet and then creates two free jets at both ends of the yarn channel. The compressed air moves in the shape of two opposing directional vortices. The CFD-FASTRAN was used to perform steady simulations of impinging jet flow inside of the interlace nozzles. The vortical structure and the flow pattern such as pressure contour, particle traces, velocity vector plots inside of interlace nozzle geometry are discussed in this paper.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.695-704
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• 2016

Rubber deposited during aircraft landing is known as the main cause of reducing surface friction force on wet surfaces. Thus, rubber deposits are removed at regular intervals for sae airplane landing. The high-pressure waterblast method, widely used for the removal of rubber deposits, is regarded as the main cause for the loss of surface material because in this method, water hits the surface directly at a high pressure. In this study, a rubber removal primer is developed to reduce surface damage by lowering the pressure of waterblast relatively during the removal of rubber deposits such that the deposits are removed efficiently even with a lower water pressure. To achieve this, basic materials appropriate for the primer were selected and their performance, penetration rate, and site applicability were evaluated. Based on the evaluations, the proportion of additive required for improving the performance of the basic materials was first determined. Then, the optimum mix ratio was derived through the evaluation of the effect on pavements, and the development of the rubber removal primer was completed.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.3
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• pp.179-184
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• 2015

In this study, the flap fatigue test of a 48 m long wind turbine blade was performed for 1 million cycles to evaluate the characteristics of acoustic emission signals generated from fatigue damage of the wind blades. As the number of hits and total energy continued to increase during the first 0.6 million cycles, blade damage was constant. The rise-time result showed that the major aspects of damage were initiation and propagation of matrix cracks. In addition, the signal analysis of each channel showed that the most seriously damaged sections were the joint between the skin and spar, 20 m from the connection, and the spot of actual damage was observable by visual inspection. It turned out that the event source location was related to the change in each channel's total energy. It is expected that these findings will be useful for the optimal design of wind turbine blades.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.212-220
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• 2013

This study analyzed the effect of fairness of personnel management systems of public organizations on job satisfaction and job performance. For hits, satisfaction, problems, and improvements of personnel management systems were investigated targeting 4 personnel management systems which are being operated in Chungcheongnam-do and analyzed the correlations between job satisfaction and job performance with it. Personnel fairness has the positive effect on job satisfaction and performance of public servants. When personnel management is done by considering career, degrees of work difficulty, and efforts, job satisfaction and performance can increase. This shows that fair personnel management plays the important role in organizations and employees' morale. As the various personnel management systems are being operated in Chungcheongnam-do, the fact that personnel management of public servants is done according to objective evaluation materials and procedures with the same principles should be recognized.

• Geomechanics and Engineering
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• v.11 no.3
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• pp.345-359
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• 2016

In order to investigate the influence of the interfacial angel on failure characteristics and mechanism of combined coal-rock mass, 35 uniaxial/biaxial compressive simulation tests with 5 different interfacial angels of combined coal-rock samples were conducted by PFC2D software. The following conclusions are drawn: (1) The compressive strength and cohesion decrease with the increase of interfacial angle, which is defined as the angle between structure plane and the exterior normal of maximum principal plane, while the changes of elastic modulus and internal friction angle are not obvious; (2) The impact energy index $K_E$ decreases with the increase of interfacial angle, and the slip failure of the interface can be predicted based on whether the number of acoustic emission (AE) hits has multiple peaks or not; (3) There are four typical failure patterns for combined coal-rock samples including I (V-shaped shear failure of coal), II (single-fracture shear failure of coal), III (shear failure of rock and coal), and IV (slip rupture of interface); and (4) A positive correlation between interfacial angle and interface effect is shown obviously, and the interfacial angle can be divided into weak-influencing scope ($0-15^{\circ}$), moderate-influencing scope ($15-45^{\circ}$), and strong-influencing scope (> $45^{\circ}$), respectively. However, the confining pressure has a certain constraint effect on the interface effect.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.751-768
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• 2016

The success of the journey to the west of tvN's shows the positive prospect of web entertainment. This study highlights how viewers actively select web progrmas and how they diffuse the infomrmation of web programs to explore the possibility of success of web program and the change of viewing environment. This study revealed the attention of viewers affected the diffusion of programs via social media. The highness of the viewer's attention cause the highness of active interaction between users. The production company of web entertaninment has to focus on the high hits strategy. In the view of journalists, they covered on the appearance of the heroin rather than the content of the program. The relationship of viewing type and viral type via SNS is related with the activity of viewers. If viewers participate in viewing they express their opinion on the web entertainment actively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.105-111
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• 2020

We defined Jeju Wind Castle and analyzed the relationship between Hallasan-Oreum-Batdam, the main subject, for the first time. In Jeju, 1.5m high Batdam(Black Silk Road), 368 Oreums, Hallasan Mountain 1950m are all unique scenery. The verification of this paper demonstrates that Samdasoo's groundwater extraction sea level is equal to the height of Hallasan and that this problem is mathematically complete in neutral plane theory. Donnaeko(700meters above sea level)-Baeknokdamdongneung-Jindallebat-Seongpanak-Gyorae(453 meters)-Witsaeoreum(1700meters) is a rain belt that hits the low-air pressure air-conditioned North Pacific humidity rising from the southeast and the high-pressure cold air of Hallasan Peak. It rains a lot because - and + are neutral plane, which adds to zero. Hallasan is called Jinsan in Jeju history. The answer is Wind Castle. The number of Oreum in Jeju is 369 including Hallasan, and Batdam, which is about 1.5m high, does not collapse even with a typhoon blowing over 50m/s. Because the wind castle's core is 1.5 meters of Batdam and it is a triangular number.

• The Korean Journal of Malacology
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• v.31 no.3
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• pp.243-247
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• 2015

A stand-alone BLAST server is available that provides a convenient and amenable platform for the analysis of molluscan sequence information especially the EST sequences generated by traditional sequencing methods. However, it is found that the server has limitations in the annotation of molluscan sequences generated using next-generation sequencing (NGS) platforms due to inconsistencies in molluscan sequence available at NCBI. We constructed a web-based interface for a new stand-alone BLAST, called PANM-DB (Protostome DB) for the analysis of molluscan NGS data. The PANM-DB includes the amino acid sequences from the protostome groups-Arthropoda, Nematoda, and Mollusca downloaded from GenBank with the NCBI taxonomy Browser. The sequences were translated into multi-FASTA format and stored in the database by using the formatdb program at NCBI. PANM-DB contains 6% of NCBInr database sequences (as of 24-06-2015), and for an input of 10,000 RNA-seq sequences the processing speed was 15 times faster by using PANM-DB when compared with NCBInr DB. It was also noted that PANM-DB show two times more significant hits with diverse annotation profiles as compared with Mollusks DB. Hence, the construction of PANM-DB is a significant step in the annotation of molluscan sequence information obtained from NGS platforms. The PANM-DB is freely downloadable from the web-based interface (Malacological Society of Korea, http://malacol.or/kr/blast) as compressed file system and can run on any compatible operating system.