• 한국자동차공학회논문집
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• 제20권2호
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• pp.78-84
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• 2012

The purpose of this study is to investigate the performance characteristics of new exhaust heat recovery device for the engine's fast warm-up. In this study, two different interior area designed for prototyping and on the exhaust heat recovery device to evaluate the performance compare the performance characteristics were chosen a better product. A company's product and selected prototype-2 were evaluated and compared the performance. This experiment was conducted under the same conditions. The time from starting to warm-up of engine was measured. As a result, the performance characteristics of the prototype-2 was not higher than that of the A company's product. However, in comparison with base system, prototype-2 of the exhaust heat recovery device discover that the warm-up time was shortened.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.333-339
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• 2000

This study was performed to investigate the performance of heat recovery device attached to exhaust gas funnel connected to combustion chamber of greenhouse heating system. The experiment heat recovery system is mainly consisted of LPG combustion chamber and two heat recovery units; unit-A is attached directly to the exhaust gas funnel, and unit-B is connected with unit-A. Heat recovery performance was evaluated by estimating total energy amount by using enthalpy difference between two measurement points together with mass flow rate of gas and/or air passing through each heat recovery unit depending on 5 different flow rates controlled by voltage meter. The results of this experimental study, such as heat exchange behavior of supply air pipes and exhaust air passages crossing the pipes, pressure drop between inlet and outlet, heat recovery performance of exchange unit, etc., will be used as fundamental data for designing optimum heat recovery device to be used for fuel saving purpose by reducing heat loss amounts mostly wasted outside of greenhouse through funnels.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E4호
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• pp.181-190
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• 2002

A novel portable device for the direct measurement of alveolar breath carbon monoxide (CO) was developed. The major components of the device include a mouthpiece, non-rebreathing two-way valve, Teflon tube, and CO dosimeter. An alveolar CO measurement can be completed within 1.5 min when using the proposed device and measurement protocol. Measurements could be read to the nearest 0.1 ppm. Humidity did not influence the CO measurements taken by the CO dosimeter, plus there were no problems associated with the recovery and carryover of CO through the device. The criterion for significance in statistical analyses was p< 0.05. The average recovery was 103 and 99% for recovery and carryover experiments, respectively. Test results using the proposed alveolar CO measurement system reflected a good reproducibility. This reproducibility was also supported by the finding that the relative standard deviations (RSDs) of the data sets were less than 7％ for the loss experiment and less than 8% for the carryover experiment. Consequently, it would appear that the proposed device can be effectively applied to measure CO levels found in breath, thereby overcoming several disadvantages associated with the conventional bag and adsorbent tube sampling methods.

• 한국전기전자재료학회논문지
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• 제19권3호
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• pp.216-221
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• 2006

Lifetime control technique by proton implantation has become an useful tool for production of modern power devices. In this work, punch-through type diodes were irradiated with protons for the high speed power diode fabrication. Proton irradiation which was capable of controlling carrier's lifetime locally was carried out at the various energy and dose conditions. Characterization of the device was performed by current-voltage, capacitance-voltage and reverse recovery time measurement. We obtained enhanced reverse recovery time characteristics which was about $45\;\%$ of original device reverse recovery time and about $73\;\%$ of electron irradiated device reverse recovery time. The measurement results showed that proton irradiation technique was able to effectively reduce minority carrier lifetime without degrading the other characteristics.

• 생물환경조절학회지
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• 제9권4호
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• pp.212-222
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• 2000

본 연구는 온실 난방시스템의 연소 체임버에 부착된 연소가스 배출연통에 열회수기를 장착하여 배출가스로부터 열을 회수하는 열회수장치의 성능에 대해 실험·분석하였다. 열회수시스템은 LPG 연소 체임버와 두 개의 열회수기로 구성되어있다. 열회수기-A는 배기가스 연통에 직접 연결되어 있으며 열회수기-B는 열회수기-A에 직렬로 연결되어 있다. 회수되는 열량은 가스의 질량흐름율과 두 측점간의 엔탈피 차이로서 산정하였으며 5가지의 송풍전압별로 각 열회수기의 성능을 검토하였다. 각 열회수기의 공기튜브 다발에 공급된 공기와 튜브 다발에 가로질로 통과하는 연소가스간의 열교환, 열회수기 유·출입부간의 압력감소, 열회수기의 총열회수성능 등으로 온실의 연통을 통해 낭비되는 열을 회수하여 연료 절감 효과를 얻을 수 있는 최적의 열회수장치 설계용 기초자료 확보에 본 연구의 목적이 있다.

• 한국항공우주학회지
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• 제47권1호
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• pp.49-58
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• 2019

과학기구는 임무 종료시 전체 플랫폼의 안정적인 회수가 가능한 비행 시스템이다. 과학기구의 회수는 인명 및 재산피해를 고려하여 인구밀집도가 낮은 평야지대에서 주로 진행된다. 하지만 대한민국의 경우 밀집한 산악지형과 반도의 제한으로 인해 해상회수가 고려되어야 한다. 이러한 운용환경에서 기낭은 해상 착수 후 발생할 수 있는 심각한 해양오염 때문에 반드시 회수되어야 한다. 따라서 본 논문에서는 기낭의 위치추적기 및 방수체계가 결합된 분리장치를 개발하였다. 장치는 데이터 송수신, 분리, 방수 체계로 구성되었고 대한민국의 환경을 고려하여 제작하였다. 장치의 성능과 기낭의 낙하 궤적은 목표고도 20km 플랫폼의 분리 실험과 영압력 기구의 해상회수를 진행하여 검증하였다.

• 동력기계공학회지
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• 제18권4호
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• pp.52-59
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• 2014

The purpose of this study is to evaluate the performance of after-treatment equipment and thermal storage devices for a heat recovery and combustor-type $CO_2$ generator fuelled a kerosene. To reduce the levels of harmful exhaust gases produced by a $CO_2$ generator, a catalyzed particulate filter(CPF) has been selected as an after-treatment device, by considering back pressure and exhaust gas temperature. The CO conversions of the catalyzed SiC filter(full plugging) were 92%, and the concentration of PM(particulate matter) was near ambient. A thermal recovery device was used to recover 13% of the heat energy from the exhaust gas through heat exchangers installed on the exhaust line of the $CO_2$ generator. 69% of the moisture within the exhaust gases was removed by condensing water, in order to minimize excessive humidity within the greenhouse.

• 한국전기전자재료학회논문지
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• 제20권5호
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• pp.415-420
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• 2007

Generally, a diode package consists of the synthetic resin that has good durability but low thermal conductivity. The surface mounted type fast recovery diode was fabricated by using ceramic package. Its main manufacture processes are composed of soldering, sillicon coating and side termination. And it has various advantages that diode is small, easy manufacture and fast cooling. The electric characteristics of the diode such as reverse recovery time, breakdown voltage, forward voltage, and leakage current were 5.28 ns, 1322 V, 1.08 V, $0.45\;{\mu}A$, respectively.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.3-6
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• 2003

We have developed a small-sized superconducting magnetic energy storage (SMES) device, which provides electric power with high quality to sensitive electric loads. In large magnets such as the SMES magnets the stability, which is determined by several factors, e.g. conductors cooling condition and operating current, magnets winding structure, is a crucial problem. The effect of the cooling condition, the copper ratio, and the conductor's size upon the recovery currents was investigated experimentally. The results indicate that the recovery current characteristics of the strands vary considerably according to their insulation method. In the fully insulated strands with a low copper ratio, the recovery current densities range from 10 to 20 % of their engineering critical current densities. The recovery current density of the 30-conductor with a cooling channel is about a factor of 1.8 higher than that without a cooling channel.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.153-158
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• 2013

The purpose of this study is to investigate the performance characteristics of the counterflow exhaust heat recovery device for the applied gasoline engines. The EHRS device is installed behind the catalyst. This study investigates the engine warm-up characteristic, the exhaust noise characteristic, the back-pressure characteristic. The engine warm-up characteristics is (load 0%, load 10%, load 20%) in (idle, 1000rpm, 1500rpm, 2000rpm, 2500rpm) conditions by measuring the time it warmed up, coolant temperature ($25^{\circ}C{\sim}80^{\circ}C$) until the performance evaluation is performed. The wide open throttle and the coast down the exhaust noise and the back-pressure characteristic experiment repeated twice. The test conditions is 950rpm~6,050rpm proceed experiment repeated 3-5 times. Load 0% idle conditions except the results improved engine warm-up characteristics. The exhaust noise obtain similar results the BASE+EHRS W/O_FRT_MUFF with BASE and back-pressure to obtain similar results BASE+EHRS W/O_FRT_ MUFF with BASE+EHRS.