• The Journal of Internal Korean Medicine
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• v.36 no.3
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• pp.297-307
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• 2015

Objectives: We aimed to evaluate the effect of Cervi Cornu and coenzymeQ10 on exercise and endurance capacity in rats and mice. Methods: The extract of Cervi Cornu was manufactured by the pharmacy department of Kyung Hee Oriental Medical Hospital, and CoQ10 soft cap (Ildong Pharmaceutical) was used. In total, 24 rats and 30 mice were divided into 3 groups: Control (rat=8, mouse=10), CoQ10 alone (rat=8, mouse=10), Cervi Cornu extract, and CoQ10 (rat=8, mouse=10). Ergogenic effect was evaluated by administering the Cervi Cornu extract and coenzymeQ10 to rats and measuring the time to exhaustion during treadmill running; endurance capacity was assessed by measuring cold water swimming time, serum lactate level, and serum corticosterone level in each group. At 1 week from the end of treatment, we recalculated time to exhaustion during treadmill running in rats to investigate the long-term effect of the Cervi Cornu extract and coenzymeQ10. Results: Cervi Cornu extract has long-term benefits in that it preserves the ergogenic effect caused by exercise. Cervi Cornu and coenzymeQ10 have no effect on increasing cold water swimming time in ICR mice. CoenzymeQ10 decreases the serum corticosterone level in ICR mice performing cold water swimming test. Conclusions: Cervi Cornu seems to preserve the ergogenic effect caused by exercise, but a larger study is needed to investigate effect of Cervi Cornu and coenzymeQ10 on improving endurance capacity. CoenzymeQ10 decreases serum corticosterone level and it is related with the anti-psychological fatigue effect.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.11
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• pp.940-947
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• 2012

The target system is a middle size UAV, which is a low-speed long-endurance UAV with a weight of 18 kg and wingspan of 6.4 m. Three electric power sources, i.e. solar cells, a fuel cell, and a battery, are considered. The optimal takeoff time is determined to maximize the endurance because the generated solar cell's energy is heavily dependent on it. Each power source is modeled in Matlab/Simulink, and the component models are verified with the component test data. The component models are integrated into a power system which is used for power simulations. When takeoff time is at 6 pm and 2 am, it can supply the power during 37.5 hrs and 27.6 hrs, respectively. In addition, the thermostat control simulation for fuel cell demonstrates that it yields more power supply and efficient power distribution.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.1-9
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• 2013

In order to increase endurance flight efficiency of long endurance electric powered UAV with solar cell, the light weight airframe design techniques are important. In this paper, the design of the main wing of electric powered UAV manufactured using Mylar film and fiber reinforced composite was conducted in order to achieve weight reduction and structural integrity of the structure. The shape of spar and size were determined using beam theory analysis. The finite element analysis of the wing was performed under various load condition derived from flight environment of EAV-2H. Finally, the static strength test of the main wing was conducted to verify structural integrity. It was found that the developed main wing weigh less than 42% than the previous EAV-2 and the main wing passed static strength test under ultimate load.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.4
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• pp.405-418
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• 2014

Fuel cells are suitable for a power plant of a unmanned aerial vehicle (UAV) as it is not only environmentally friendly and quiet but also more efficient than an internal combustion engine. A fuel cell hybrid UAV has better performance in endurance than a fuel cell only or battery only UAV. One of the key purposes of making fuel cell hybrid UAVs is having long endurance and now maximum 26 hours of flight is possible. Because optimal design and control methods for fuel cell hybrid UAVs are absolutely needed for their long endurance we have to check the methods. The aircraft made by using application-integrated design method has less BOP mass and better performances. The optimal design and control methods are generally based on computer simulations or Hardware-In-The-Loop simulations by using dynamic models for their design and control. The Hardware-In-The-Loop simulation (HILS) is to use a hardware device like a fuel cell stack as well as a simulation program and it allows for making optimally designed applications. This paper introduce efficient methods of design, control and evaluation for the fuel cell hybrid UAVs.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.471-478
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• 2022

This paper is about research and development of Korea Aerospace University's Solar-Powered UAV System that named of KAU-SPUAV, and describes the design process of the 4.2 m solar UAV that succeeded in a long flight of 32 hours and 19 minutes at June 2020. In order to improve the long-term flight performance of the KAU-SPUAV, For reduce drag, a circular cross-section of the fuselage was designed, and manufactured light and sturdy fuselage by applying a monocoque structure using a glass fiber composite material. In addition, a solar module optimized for the wing shape of a 4.2 m solar drone was constructed and arranged, and a propulsion system applied with the 23[in] × 23[in] propeller was constructed to improve charging and flight efficiency. The developed KAU-SPUAV consumes an average of 55W when cruising and can receive up to 165W of energy during the day, and its Long-term Endurance was verified through flight tests.

• 보존과학연구
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• s.21
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• pp.145-175
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• 2000

To examine the method for preservation of papers, 9 kinds of papers were purchased and pretreated for 6 months with various artificial conditions which were controlled as 3 temperature classes($20^{\circ}C$, $80^{\circ}C$, $-20^{\circ}C$&$20^{\circ}C$) and 4 humidity classes(40%, 60%, 80%, 100%).Whiteness, acidity and folding endurance were measured to examine the state of papers pretreated under each condition. From the resultexamining the state, all the papers were best condition at low temperature($20^{\circ}C$) and low humidity(40%) and damaged at high temperature($80^{\circ}C$) and high humidity(100%).The values of whiteness, acidity, and folding endurance were measure din relation with deterioration of papers. According to damage of papers caused by the chemical agent, papers became to be acidic, increased color difference and reduced the force of folding endurance. The effect of change of temperature($-20^{\circ}C$&$20^{\circ}C$) on degradation of papers was not well acquired. Because the period of investigation was not long enough to acquire the data. So the more studies are needed to find the cause of damage of papers.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.867-873
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• 2008

Model based virtual Flight Control System construction is essential for Fly-by-Wire Flight Control System verification & validation(V&V) of concurrent engineering base. We researched the concept of dual-architecture system for virtual system construction, and analyzed Flight Control System that is applied to high altitude long endurance(HAE) UAS. Finally, we constructed the model based virtual Flight Control System with system analysis and achieved system verification about flight critical failure modes. Analysis target is RQ-4A.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.2
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• pp.27-33
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• 2014

There are several methods to improve the flight efficiency of HALE(High Altitude Long Endurance) UAV(Unmaned Aerial Vehicle). Airframe structural point of view, weight reduction of the airframe structure is the most important method to improve the flight efficiency. In order to reduce the weight of airframe structures, new concepts which are different from traditional airframe structure design such as the mylar wing skin should be introduced. The spar is the most important component in a mylar skin wing structure, so the spar weight reduction is the key point for reduction of the wing structural weight. In this study, design trade-off study for the front spar of the HALE UAV wing is conducted in order to reduce the weight. Design and analysis procedure of high aspect ratio wing spar are introduced. Several front spar structures are designed and trade-off study regarding the weight and strength for the each spar are performed. Spar design configurations are verified by the static strength test. Finally, optimal front spar design is decided and applied to the HALE UAV wing design.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.77-84
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• 2015

Recently, as the needs for eco-friendly aero propulsion system increase gradually, many study works have been conducted to develop the hybrid propulsion system for High Altitude Long Endurance(HALE) UAV. In this study, we analyzed both suitable energy distribution and management methodology among the total energy collected from solar cell and the total required energy of aerial vehicle and required energy of the regenerative fuel cell(RFC) for driving in the night time and optimized the energy balance mechanism based on the ascribed mission profile.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.10 no.3
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• pp.399-407
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• 2003

Purpose: This study was done to identify levels of physical fitness in student nurses and to ascertain the relationship among the different aspects of physical fitness of strength, power, muscle endurance, agility, balance and flexibility. Method: The participants were 266 students selected from one college of nursing. From May 1 to July 31 in 2003, physical constitution, muscle strength (grip strength, back strength), power (standing long jump), muscle endurance (sit-ups), agility (whole body reaction time-light, sound), balance (close-eyes foot-balance), and flexibility (sitting trunk flexion) were measured. Result: The mean(standard deviation) for grip strength was 22.59(3.93) kg., for back strength, 48.52(12.85) kg., for standing long jump, 135.29(20.54) m., for sit-up's, 23.66(9.35) per minute, whole body reaction time (light), 0.43(0.11) sec, whole body reaction time (sound), 0.50(0.16) sec, close-eyes foot-balance, 33.35(38.67) sec, and sitting trunk flexion 34.72(9.37) cm. Conclusion: This study showed that the physical fitness of student nurses is very low compared to the results in a report from the Korea Sports Science Institute. It is necessary to include exercise programs for student nurses in order to improve their physical fitness.