• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.1
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• pp.67-73
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• 1998

In this paper, the electron swarm parameters in the 0.5% and 0.2% SF\ulcorner+Ar mixtures are measured by time of flight method over the E/N(Td) range from 30 to 300(Td). The measurements have been carried out by the double shutter drift tube with variable drift distance from the cathod. A two-term approximation of the boltzmann equation analysis and Monte Carlo simulation have been also used to study electron transport coefficients. We have calculated W, $ND_L,\;ND_T,\;\alpha,\;\eta,\;\alpha-\eta$, and the limiting breakdown electric field to gas mixtures ratio in pure $SF_6$+Ar mixtures. The electron energy distribution function has been analysed in $SF_6$+Ar mixtures at E/N : 200(Td) for a case of the equilibrium region in the mean electron energy. The measured results and the calculated results have been compared each other.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.24-27
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• 2012

In this study, the full scale flight type Dual-Pulse Rocket Motor(DPRM) with the bulkhead type Pulse Separation Device(PSD) was designed, manufactured, and fire-tested. The bursting time and pressure of PSD were analyzed by the pressure, thrust and vibration results of static fire tests and ablation of PSD was measured with 3-D coordinate measuring machine. As a result, PSD requirements, bursting conditions and thermal safety, were satisfied.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.4
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• pp.73-80
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• 2013

Endothermic fuel utilizing technology is considered as a unique practical method of hypersonic vehicle for long distance flight. Research activities about characteristics of fuel injection and combustion using cracked by endothermic reaction are reviewed. Studies on characterization of supercritical fuel injection and mixing within supersonic flow field are surveyed. Researches on combustion characteristics such as ignition delay time, laminar burning velocity and combustion efficiency at supersonic model combustor are reviewed. In addition, domestic research activities on endothermic fuel are surveyed.

• Journal of Convergence for Information Technology
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• v.9 no.12
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• pp.157-165
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• 2019

Charles Lindbergh has experienced the uncontrolled situation of the aircraft while he was asleep with open eyes during his Atlantic crossing flight around 20 hours after departure from the New York in 1927 because of the fatigue. According to the NTSB(National Transportation Safety Board) reports, about 40 incidents are related fatigue in each year. The sleep loss is the most wanted item for the NTSB and may cause the similar effect as the alcohol does. The fatigue may affect the management of the threats and errors especially during take-off and landing. In this study, threats and errors of major accidents that NTSB analysed fatigue as a causal factor will be identified in order to understand the seriousness of fatigue.

• Nuclear Engineering and Technology
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• v.4 no.2
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• pp.116-131
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• 1972

A fast neutron time-of-flight spectrometer has been constructed with suitable choice of target thickness and proton bombarding energy in Li$^{7}$ (p, n) Be$^{7}$ nuclear reaction for a continuous keV spectrum of neutrons at 0 degree in 1-nsec pulse from a Van do Graaff and a time-pick-up fast neutron detector assembled with a 5 mm-thick 92% enriched B$^{10}$ slab and four heavily shielded 4＂$\times$3＂ NaI scintillation detectors. Energy resolution of this spectrometer is better than 0.3% at 50 keV and the signal-to-background ratio is also improved. Total cross section measurements of several separated single isotopes have been carried out with this spectrometer and analyzed by Rmaxtrix multi-level computer code. The spin values and resonance parameters of each individual resonances are given.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.75-80
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• 2019

In the recent aerospace and defence industries, it is required to develop small and low cost embedded systems. Based on a high speed digital signal processor (DSP), this paper first presents the development of an embedded system. To reduce the computation time of the high precision algorithm such as flight control, we also propose two algorithms for matrix multiplication. Validation results show that, compared to the performance using the $2{\times}2$ unit method, the performance of the proposed method 1 is improved, when the size of matrices is small. The proposed method 2 generally outperforms the $2{\times}2$ unit method.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.4
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• pp.79-88
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• 2020

Hypergolic propellants have been widely used for space propulsion systems based their long-term storability and high ignition reliability. Since conventional hypergolic propellants are highly toxic and carcinogenic, handling and operating costs are significant. To overcome the drawbacks, numerous studies have been actively performed to develope new hypergolic propellants, ensuring that the combinations are high performance, low toxicity and low environmental impact. In the present study, a comprehensive survey was conducted to summarize the research and development of green hypergolic propellants involving hydrogen peroxide, nitric acid, and ionic liquids.

• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.43-48
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• 2022

The Kinzal missile launched by Russia in Ukraine and flew on March 5 or more speeds is the first hypersonic cruise missile used in combat. High speed leads to destructive solid power, and the security system's interception time is significantly reduced. Therefore, hypersonic missiles could be a game-changer. Even the United States, with its multi-layered defense system, admits the difficulty of intercepting it. Military powers like the United States, Russia, China and North Korea are focus on developing hypersonic missiles as offensive weapons, but their defense system capabilities are inadeqate. From this perspective, this paper identifies significant countrie's hypersonic missile development status and defense system capabilities and seeks to derive a countermeasure for the ROK military.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.502-504
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• 2021

The application area based on UAV(Unmanned Aerial Vehicle) is continuously increasing as time passing by. In particular the UAVs which consist of more than four horizontal propellers and the functionality of VTOL (Vertical Take-Off and Landing) are utilized in diverse platforms and application products due to their safety and aerodynamically simpler design and architectures. Most UAV missions are controlled by GCSs(Ground Control System). The GCSs are generally connected to the internet and get electrical map and environmental information such as temperature, humidity, wind direction and so on. In this paper, we design a system that UAV has capability of approaching to a certain ship and monitoring her efficiently by using AIS(Auto Identification System) information.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.133-140
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• 2002

In this paper, the structure of integrated navigation computer for experiment is proposed. It is designed for considering the real time processing and data storage capacity. It will be used in missile, aircraft, submarine system and experimental vehicle. The I/O device supports IMU, GPS, odometer, altimeter, depth sensor, inclinometer etc. And the main storage device uses the tape device. That can improve the system stability. Therefore it can be used in a high dynamic or shock environment. The embedded linux is used as an Operating System. For the real time capability, sensor data processing and algorithm processing units are seperated. The time synchronization is referenced by IMU data.