• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.3
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• pp.234-240
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• 1997

터보 챠저의 반동도와 터빈 노즐유량의 변화를 행하여 엔진의 성능을 향상시킬 수 있었다. 터빈의 에너지 손실과 그 영향을 미치는 반동도 및 터빈 입구의 유로의 변화, 그리고 블레이드에서 역 유동에 대한 개선 조건도 제시하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1391-1398
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• 2011

Design and performance analysis of a steam turbine for variations of degree of reaction were performed by computer simulation. Design parameters such as blade angles, exit areas, and heights of the nozzle and moving blade were represented as functions of the degree of reaction. The main performance factors such as turbine power, diagram efficiency, and axial thrust were also expressed in terms of the degree of reaction. For further information about the design and performance, the blade angles and main performance factors were investigated as functions of the flow coefficient. The turbine power and diagram efficiency reached a maximum value for a given degree of reaction and flow coefficient, and the symmetric shape of the moving blade showed distortion as the degree of reaction was increased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.277-283
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• 2017

In this study, we investigated how a jumping strategy changes with an increase in the vertical jump height for a resultant ground reaction force (GRF) vector. We expected that the resultant force vector between two sequential motion phases (i.e., countermovement and push-off) of the countermovement jump would significantly change with the vertical jump height to take advantage of the resulting supportive force (i.e., an initial push-off force larger than the body weight) through the countermovement phase. Nine healthy young subjects were instructed to jump straight up to five different height levels ranging from 191 cm to 221 cm, and the kinematic and kinetic data were obtained in regular trials. The results showed that a lower center of mass position and larger resultant force vector were clearly observed in a higher jump, implying that the countermovement strategy changed with the vertical jump height to prepare for sufficient joint deviation and obtain a force advantage for larger push-off work.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.145-148
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• 2008

Korea Aeronautics Research Institute (KARI) is developing a turbo pump that has 1-stage impulse turbine and relatively high tip clearance for safety. The objective of this research is to investigate the effect of reaction on tip clearance loss in axial turbines. Both cascades were tested in a subsonic wind tunnel. In each cascade, total pressure was measured for tip clearance ranging from 1% to 20% of chord. In results, increasing tip clearance, total pressure loss in reaction turbines is continually increased but impulse turbines keep almost same level of mass averaged total pressure loss. When tip clearance becomes more than 10% of chord, mass-averaged total pressure loss in impulse turbines is less than in reaction. This means that when tip clearance is more than 10% of chord, impulse turbines have better efficiency than reaction turbines.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.1033-1036
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• 1996

In Pistol, the peak recoil force affects the reliability of the frame and the accuracy of target shooting. To attenuate the peak recoil force of pistol, we develop measuring test bed, which consists of force sensors, linear sensor and a high speed video camera, execute tests with several Pistol models and compare the results measured.

• Defense and Technology
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• no.5 s.123
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• pp.6-17
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• 1989

• Defense and Technology
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• no.10 s.10
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• pp.56-59
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• 1979

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.4 s.334
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• pp.1-6
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• 2005

For the low power and low cost transceivers, direct sequence spread spec01m frequency-shift keying (DSSS-FSK) is proposed. A transmitter of the DSSS-FSK signal can be implemented by a simple direct modulation using the phase locked loop. Since the DSSS-FSK signal has negligible power around the carrier frequency, low cost direct conversion receiver can be used. Optimum coherent and semi-coherent correlation detection methods for the DSSS-FSK signal are proposed and analyzed. Segmented semi-coherent correlation detection method is proposed to improve the bit error rate performance in the large carrier frequency offset.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.87-94
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• 1999

The peak recoil force in a pistol have an effect on the reliability of the frame and target shooting. The experimental system has been established for measurement of the peak recoil force, which consists of force and velocity sensors, high speed camera. For effective operation of the system, a software has also developed, and combined with the hardwares. Several pistols have been tested and compared quantitatively on the peak recoil force and impact energy. It is concluded that the established system can be utilzed for checking peak force, and data accumulation for new pistol design.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.125-130
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• 2016

A low-recoil direct gun is useful in reducing the fire impulse generated by using a traditional shell. To apply a control equation to an AMESim Model, we have formulated a control equation for a recoil mechanism from the free object diagram. By modeling this equation, we have been able to compare the recoil distance and recoil force of a low-recoil direct gun. Here, we can analyze the recoil characteristics between traditional direct guns and low-recoil direct guns with perforated muzzle brakes. It is possible to mount a low-recoil direct gun with a perforated muzzle brake on a lightweight tracked vehicle by reducing its fire impulse.