• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.1-4
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• 2008

Fuel cells have the potential of providing several times higher energy storage densities than those possible using current state-of-the-art lithium-ion batteries, but current energy density of fuel cell system is not better than that of lithium-ion batteries. To achieve the high energy density, volume and weight of fuel cell system need to be reduced by miniaturizing system components such as stack, fuel tank, and balance-of-plant. In this paper, the thin flexible PCB (Printed circuit board) is used as a current collector to reduce the stack volume. Two end plates are made from light weight aluminum alloy plate. The plate surface is wholly oxidized through the anodizing treatment for electrical insulation. The opening rate of cathode plate hole is optimized through unit cell performance measurement of various opening rates. The performances are measured at room temperature and ambient pressure condition without any repulsive air supply. The active area of MEA is 10.08 $cm^2$ and active area per a unit cell is 1.68 $cm^2$. The peak power density is about 210 mW/$cm^2$ and the air-breathing planar stack of 2 Wis achieved as a small volume of 18 cc.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.74-82
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• 2000

The concept and characteristics of the propulsion systems for the next generation flight vehicles are described in this paper, where Hey are grouped into air breathing engine, rocket engine and combined cycle engine according to the feeding system of oxidizer. Air breathing engine has its good reusability and superior performance at low altitude, but its usage is limited at high altitude due to the decreased air density. Rocket engine can be used over the wide range of altitude, but it has disadvantages in low specific impulse and high cost. The several types of combined cycle engine, which are being developed by the leading countries in the aerospace, are highlighted as a remarkable candidate for the next generation propulsion system.

• Journal of Korea Multimedia Society
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• v.21 no.9
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• pp.1076-1089
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• 2018

Respiration is the process of moving air into and out of the lung. Respiration changes the temperature in the chamber while exchanging energy. Especially the temperature of the face. Respiration monitoring using an infrared camera measures the temperature change caused by breathing. The conventional method assumes that motion is not considered and measures respiration. These assumptions can not accurately measure the respiration rate when breathing moves. In addition, the respiration rate measurement is performed by counting the number of peaks of the breathing waveform by displaying the position of the peak in a specific window, and there is a disadvantage that the breathing rate can not be measured accurately. In this paper, we use KLT tracking and block matching to calibrate limited weak movements during breathing and extract respiration waveform. In order to increase the accuracy of the respiration rate, the position of the peak used in the breath calculation is calculated by converting from a single point to a high resolution. Through this process, the respiration signal could be extracted even in weak motion, and the respiration rate could be measured robustly even in various time windows.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.1
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• pp.137-146
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• 2020

Purpose : The enhancement of abdominal muscles increases the activation and contraction of respiratory muscles, including the diaphragm. Generally, diaphragm exercises are applied to increase the breathing ability of patients with respiratory disease. Previous studies have shown that breathing capacity can be increased through abdominal muscle strengthening exercises. However, studies on breathing ability are rare and it is doubtful whether these affect respiratory ability more than diaphragm exercises. Therefore, this study seeks to compare whether abdominal exercises can improve breathing ability and whether any increase is comparable to diaphragm exercises. Methods : After selecting subjects, the place of intervention was separated for blindness. The plank group was allowed to relax for 30 seconds after 30 seconds of planking; this was set at three and increased by one set each week. Subjects in the draw-in group were allowed to relax for 30 seconds after maintaining the draw-in contraction state for 30 seconds and this was done for 15 minutes. Subjects in the control group underwent abdominal dilation for five seconds of inspiration time and expired air for five seconds by exposing the lips; breathing was performed repeatedly for 15 minutes. Subjects in each group measured their respiration function three times before intervention, three weeks after the commencement of intervention and after intervention. Spirovit SP-1 was used to measure respiratory function. In each group, repeated ANOVA was used to compare the respiratory function over time and one-way ANOVA was used to compare the respiratory function between groups. The post hoc was conducted using the LSD method. Results : There was a significant increase in respiratory ability between the forced vital capacity (FVC), forced expiratory volume in one second (FEV₁) and peak expiratory flow (PEF), forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC) according to the six-week period. However, there was no difference between each group. Conclusion : For patients with low respiratory muscle strength, plank exercises and abdominal draw-in are beneficial exercises for improving respiratory function. These are expected to be widely used in clinical practice for patients with weak respiratory muscles.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.319-323
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• 1999

This study was designed to evaluate the exposure to benzene by residents in neighborhoods near a major roadways, by persons waiting buses, and by drivers and service station attendants while refueling. It was confirmed that the outdoor air benzene concentrations near the major roadways were higher than those further away from the sources. However, neither the indoor air nor breath concentrations were different for two specified residential areas. Smoking was confirmed as an important factor for the indoor air benzene levels. Persons waiting buses, drivers and service station attendants were exposed to elevated benzene levels compared to even the residents in neighborhoods near a major roadways. The mean benzene concentration at bus stop was 2.7 to 6.9 times higher than the mean ambient air concentration. The mean benzene concentrations in the breathing zone of drivers and service station attendants were 95 to 160 and 120 to 202 times higher than the mean ambient air concentrations, respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.992-995
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• 2011

A study on the performance design schemes of the supersonic air intakes applied to the supersonic air-breathing propulsion system(Ramjet/Scramjet) was conducted and for two kinds of air intakes, the preliminary configuration designs and the performance analysis models were established. For axisymmetric conical air intake and two dimensional rectangular air intake, the performance effects were assessed according to compression angles and shock wave numbers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.6
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• pp.581-588
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• 2000

This paper describes the effect of vertical air circulation on the thermal environment in an airport passenger terminal with induced flow by jet fans. In comparing the level of thermal comfort at the breathing line of 1.5 m in height, the results from the two models with or without the vertical air circulation, show that the average PPD is 8% in the former and 23% in the latter, respectively. It is thought that vertical air circulation lends to improved thermal comfort for human in respect of ventilation in a large space.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.69-78
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• 2010

Korea Aerospace Research Institute started on design and development of a hypersonic air-breathing engine test facility from 2000 and completed the test facility installation in July 2009. This facility, designated as Scramjet engine test facility(SeTF), is a blow-down type high enthalpy wind tunnel which has a pressurized air supply system, air heater system, free-jet test chamber, fuel supply system, facility control/measurement system and exhaust system. In this paper, details of the specifications, and configuration of the SeTF are described. For verifying characteristics of the SeTF, wind tunnel tests are now on progress and some of the data are also described.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.803-804
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• 2012

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.10
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• pp.99-110
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• 2006