• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.1
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• pp.26-34
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• 2016

Military devices and systems powered by batteries need to operate at extreme temperature and estimate the available capacity of the battery at different temperature conditions. However, accurate estimation of battery capacity is challenging due to the temperature-sensitive nature of electrochemical energy storage. In this paper, Peukert's equation with temperature factor is derived, and methods for estimating the absolute capacity of lithium-polymer battery and the state-of-charge(SOC) with respect to varying currents and temperatures are presented. The proposed estimation method is experimentally verified under three different discharge currents(0.5 A, 1 A, 3 A) and six different temperatures ranging from -30 to 45 deg. C. The results show the proposed method reduces the Peukert's estimation error by up to 30 % under or at extreme condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.697-702
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• 2007

The lubricational characteristics about friction and wear has an important effect on the material quality of surface. Therefore, in the case of automobile engine oil which is used under severe running condition, or therefore, the seizure and anti-scuffing is very important. We have studied the lubricational characteristics of auto engine oil with additives using Falex wear test machine. We have obtained the studied result is as fellows. In order to more improved the surface roughness characteristics adding the P(phosphate) as additives is excellent at a low temperature. Adding the ZnDTP and Ca-phenate is excellent on the anti-wear and extreme pressure properties at the high load. Moreover, when the ZnDTP and P are added, the temperature properties is excellent because the stability is maintained in a high temperature.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.3
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• pp.211-216
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• 2019

In order to utilize the marine environment in various fields such as renewable energy and offshore plant, it is necessary to utilize the far and deep ocean. However, there is still a limit to overcome and utilize the extreme deep-sea environment. Currently, the mooring system, which is the representative position control method of floating structure, has a structural and economic limit to expand the installation range to extreme deep-sea environment. Research has been conducted to utilize wave energy by developing floater using flapping foil as an alternative for station keeping in the deep sea by University of Ulsan. Based on the research, a model test was conducted for application to actual structures. In this study, we investigate how the floating body with passive flapping foils move in regular waves with different periods and study the condition of the model that can maintain its position within a certain range by overcoming the movement.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1327-1334
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• 2011

subway has became citizen's feet which can transport over 24 million people since the era of high oil price started. Because the request of passengers for more comfortable thermal comfort is drastically increasing, the importance of comfortable environment in the passenger car is more stressed. This paper suggests an indicator whether railroad car is fitted with suitable cooling and heating equipment by applying the international climatic testing method, UIC 553, 553-1. Specified ambient temperature, humidity, solar irradiation condition, as well as extreme outside condition, can be achieved by using an environmental chamber. The change temperature and humidity in the passenger space can be monitored to judge if the passenger room is nicely air-conditioned.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.494-501
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• 2015

Nowadays, many people are trying to develop eco-friendly engines such as the electric motor and the air engine because the I.C. engine cause a lot of pollutants. Nevertheless of these effort, there are few evaluation and comparison of these engines to conventionally used I.C. engines. Because of this, it is difficult to determine that the eco-friendly engines are really energy saving engines. In this paper, the efficiency of the air engine is calculated. The air engine does not cause environmental pollution problem because it uses "Compressed air". Due to the air engine operated at a low temperature and spark-free condition, this engine can be used in extreme condition for safety. Despite the many advantages of the air engine, there are few analysis on the air engine because of an air engine is low energy density.

• Environmental Analysis Health and Toxicology
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• v.3 no.3_4
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• pp.9-15
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• 1988

The word of stress crime from Latin language as stringere and it was used in medical fields from 1935. According to Selye, all the biological bodies reveal physilolgical changes when some stimulation exceed normal levels, and consequently the pituitary gland and adrenal systems are activated. Jacob expressed that stress is the loss of homeostasis by physical, chemical, and emotional stimulation. When biological organisms receive extreme stress the amount of catecholamine excretion are increase. Author investigated the catecholamine contents in rat urine after giving the low temperature stress, noise stress, and water immersion stress. The 24 hours rat urine was collected by adding 1 ml 6 N-HCl and the sample is passed through Bio-Rex 70 samples treatment column to extract catecholamine and detected the catecholamine with HPLC-fluorescence detetor. The highest epinephrine concentration was 67.14 ng in water immersion stress condition and the dopamine concentration of 221.37 ng was shown in the low temperature stress condition.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.76.2-76.2
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• 2014

The Arches cluster is one of the compact, young, massive star clusters near the center of our galaxy. Since it is located only ~30 pc away in projection from the galactic center (GC), the cluster is an excellent target for studying the effects of star forming environment on, for example, the initial mass function under the extreme condition of GC. To estimate the initial condition of the Arches cluster, we compare our calculation results from the anisotropic Fokker-Planck method with the most recent observational data sets for the surface density and velocity dispersion profiles and the present-day mass function.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.724-729
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• 2004

An experimental method to investigate the dynamic characteristics of buoys in extreme environmental condition is established. Because the buoy model requires a resonable size for accurate experiment, the test condition in model basin that satisfies the similarity law is hardly compatible with capability of test facilities. It is suggested that the linear wave component that is unable to satisfy similarity is separated with others‥‥‥

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.356-359
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• 2004

Prelaunch thermal analysis of the KSLV (Korea Space Launch Vehicle)-I PLF (Payload Fairing) was performed to predict maximum/minimum liftoff temperatures and to evaluate of air conditioning performance. Prelaunch thermal analysis includes internal air conditioning effect, external convective heating/cooling, radiation exchange with the ground and sky, radiation between spacecraft and PLF, and solar radiation incident on PLF. Analysis was performed at two extreme conditions, hot day condition and cold day condition. The results showed that the maximum liftoff temperature was $53^{\circ}C$ and the minimum liftoff temperature was $-3.8^{\circ}C$. It was also found that conditioned air supplying, in $20{\pm}2^{\circ}C\;and\;1200\;m^3/hr$, is sufficient to keep the internal air in required temperature range.

• Journal of Aerospace System Engineering
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• v.8 no.4
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• pp.7-17
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• 2014

Objective of this paper is to introduce a new technology known as prognostics and health management (PHM) which enables a real-time life prediction for safety critical systems under extreme loading conditions. In the PHM, Bayesian framework is employed to account for uncertainties and probabilities arising in the overall process including condition monitoring, fault severity estimation and failure predictions. Three applications - aircraft fuselage crack, gearbox spall and battery capacity degradation are taken to illustrate the approach, in which the life is predicted and validated by end-of-life results. The PHM technology may allow new maintenance strategy that achieves higher degree of safety while reducing the cost in effective manner.