• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.269-276
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• 2023

In this research works, we propose a hybrid power generation system for drone capable of staying in the air for more than 1 hour. This power system converts the alternating current generated by the generator into direct current through a diode bridge circuit to charge the battery and uses a battery system having separated cells to obtain high controllability of the power system. The fuel efficiency and the power output for individual load were analyzed, and also the performance of a selected generator was studied in this paper. The drone which is equipped with the proposed hybrid power generation system calculated 0.82 ratio for weight vs power output, and flight time of drone showed 4,179 seconds.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.170-175
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• 2016

An internal combustion engine is the most widely used power source for an automobile. In order to resolve environmental problems resulting from the use of internal combustion engines, environmentally friendly automobiles such as hybrid, electric, and air-engine vehicles are being developed. The share of hybrid vehicles using battery or pure electric vehicles, which are not popular, is gradually increasing. Compared to an electric vehicle, which uses an electric motor, air-engine vehicles, which use compressed air, have hardly been developed. In this study, a compressed air engine with a scroll expander is introduced, and the potential mileage of an automobile utilizing this engine is theoretically calculated.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.177-182
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• 1999

The electrolyte was brought into contact with air and potassium carbonate concentration was measured with various contact time in order to check the effect of carbon dioxide in the air on zinc-air cell. The relationship between potassium carbonate concentration in electrolyte and battery capacity was also studied. The potassium carbonate concentration increased due to carbon dioxide absorption with increasing contact time with air, but the cell capacity linearly decreased with increasing potassium carbonate concentration in the electrolyte. The rate of carbon dioxide absorption was mainly affected by the pore size of hydrophobic membrane. Our study showed that adapting the pore of hydrophobic membrane decreased the loss of cell discharge performance due to the presence of carbon dioxide or water vapor in the atmosphere.

• Proceedings of the KIEE Conference
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• summer
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• pp.992-994
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• 2004

In this paper, hybrid electromagnets using NdFeB permenant magnet are designed by 3-dimensional finite element analysis. Four hybrid magnets levitate the carrier of which total weight including control circuits and battery is 14[kg]. The nominal air gap length of the hybrid magnet is 3[mm]. The control circuit consists of DSP, 4-quadrant chopper, and gap sensor as feedback sensors. As a result, some experimental results for the magnetic levitation control by PI feedback control theory are shown.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.11a
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• pp.14-16
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• 1994

The development of proton exchange membrane fuel cells(PEMFCs) with high energy efficiencies and high power densities is gaining momentum because their performance characteristics are attractive for terrestrial(power sources for electrical vehicles, stand-by power), space and underwater application[1]. Fuel cells are capable of running on non-petroleum fuels such as methanol, natural gas or hydrogen and also have major impact on improving air quality. They virtually eliminate particulates, NO$_{x}$, SO$_{x}$, and significant reduce hydrocarbons and carbon monoxide. Especially, fuel cell-battery hybrid power sources appear to be well suited to overcome both the so-called battery problem(low energy density) and the fuel cell problem(low power density)[2].[2].

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.5
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• pp.401-409
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• 2021

The combination of different concentrations of ZnSO₄ in acidic solution as electrolyte in Zn-air batteries was investigated by Zn symmetrical cell test, half-cell and full cell tests. Using 1 M ZnSO₄ + 0.05 M H₂SO₄ as electrolyte and MnO₂ as air cathode catalyst with Zn foil anode, this combination had a satisfactory performance with balance of electrochemical activity and stability. Its electrochemical activity was matched to or even better than the PtRu catalyst in different current density. And its cycle life was improved (more than 100 cycles stable) by suppressing the growth of zinc dendrites on anode obviously. This electrolyte overcame the shortcomings of alkaline electrolyte that are easy to react with CO₂ in the air, severely growth of Zn dendrites caused by uneven plating/stripping of Zn.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.201-208
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• 2022

As around the world, ground and underground transportation capacity is reaching its limit, centering on urban areas. As urban traffic becomes congested, time and cost are astronomical, and environmental destruction caused by urban pollution is becoming increasingly serious. As a way to solve this problem, the means of flying over the air are in the spotlight as the next generation of future transportation, and the concept of urban air mobility (UAM, Urban Air Mobility) is defined as systematic planning. The development of an electric-powered vertical take-off (eVTOL) aircraft that obtains electric power through a battery using a personal aerial vehicle (PAV) as a means of transportation has accelerated. As the aircraft development of new technology aircraft in the evtol method is actively carried out, the need to prepare systems such as aircraft certification standards, pilot qualification systems, and qualification management is emerging. The Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA), which lead international standards, announced new special technical conditions and temporary regulations SCVTOL-01, respectively. However, the pilot qualification system for operating the uam aircraft has not yet been clearly announced. Therefore, this paper analyzes the recently announced FAA regulations and EASA regulations to identify differences and directions in perspectives on UAMs and study the existing vertical take-off and landing aircraft (VTOL) pilot qualification system to present directions for qualification classification.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.98-106
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• 2022

Metal-organic frameworks (MOFs) are widely used in various fields because they make it easy to control porous structures according to combinations of metal ions and organic linkers. In addition, ZIF (zeolitic imidazolate framework), a type of MOF, is made up of transition metal ions such as Co²⁺ or Zn²⁺ and linkers such as imidazole or imidazole derivatives. ZIF-67, composed of Co²⁺ and 2-methyl imidazole, exhibits both chemical stability and catalytic activity. Recently, due to increasing need for energy technology and carbon-neutral policies, catalysis applications have attracted tremendous research attention. Moreover, demand is increasing for material development in the electrocatalytic water splitting and metal-air battery fields; there is also a need for bifunctional catalysts capable of both oxidation/reduction reactions. This review summarizes recent progress of bifunctional catalysts for electrocatalytic water splitting and metal-air batteries using ZIF-67. In particular, the field is classified into areas of thermal decomposition, introduction of heterogeneous elements, and complex formation with carbon-based materials or polyacrylonitrile. This review also focuses on synthetic methods and performance evaluation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.6
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• pp.66-72
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• 2012

The main sources of energy consumption in warehouses are MHE(Material Handling Equipment), HVAC(Heating, Ventilating and Air Conditioning) and Lighting. Warehouses in advanced countries raise energy efficiencies with energy consumption diagnosis, technology development and systematic management and improvements for MHE, HVAC and Illuminating, etc. They have managed illuminating system, air conditioning, motor driven system, air circulation method, dock facility, layout, AS/RS, conveyor system and battery management, etc. Ansong Pyeongtaek area investigation resulted that 43.9[%] of enterprises are managing partly energy consumption source. But the data resulted with not substantial management of energy consumption but passive management for only electric bill curtailment. Therefore through survey research & visiting interviews of some companies in Ansong Pyeongtaek area, we understood the status of energy consumption source management and proposed energy efficiency methods on the basis of that results.

• Journal of the Korean Electrochemical Society
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• v.21 no.1
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• pp.12-20
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• 2018

To solve low cycle efficiency of the zinc anode in Zn-air batteries by corrosion, this study examined the effects of Al as a cathodic protection additive to Zn. The Al-mixed Zn anodes were produced by mixing Zn and Al powder (1, 2, and 3 wt. %). To compare the effects of the Al additive, Si was selected under the same conditions. The morphology and elemental composition of the additives in the Zn were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and inductively coupled plasma - mass spectrometry. The anti-corrosion effects of the Al and Si-mixed Zn anodes were examined by linear polarization. Cyclic voltammetry and charge-discharge tests were conducted to evaluate the electrochemical performance of the Al and Si-mixed Zn anodes. As a result, the Al-mixed Zn anodes showed highest corrosion resistance and cycling performance. Among these, the 2 wt.% Al-mixed Zn anodes exhibited best electrochemical performance.