• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.91-102
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• 1997

In order to evaluate the effects of aging on the ignition performance, pyrotechnic igniters were separated from twelve-year-old, fifteen-year-old, and sixteen-year-old live rocket motors. The characteristic values of the ignition material were measured, and the firing tests of the igniters were performed. The moisture content, the outer dimension, the crush strength, the thermal decomposition characteristics, and the heat of formation the B/$KNO_3$ ignition pellet were measured. The crush strength was increased and the heat of formation was reduced as aged, but no change was detected for other characteristic values. The burning test results of the igniter pellet in the closed bomb and the inert motor showed that the burning rate of the ignition pellet was increased by 10%, and the integration of pressure $P_t$ of the p-t curve was reduced by 15% for aged samples. It was inferred that the burning rate was increased as the crack was appeared in the pellet and $P_t$ could be proportionally decreased with the heat of explosion.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.117-119
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• 2017

The multi-stage catalytic igniter for hybrid rocket auto ignition is described in this paper. After charging the catalyst and pre-heating the first stage, the $N_2O$ was supplied at the first stage with the low mass flow rate, and then the $N_2O$ with the high flow rate was supplied into the second stage. Even though the $N_2O$ flow rate was high, it was decomposed by supplying the high temperature gas which was evolved from the $N_2O$ decomposition in the first stage. This multi-stage ignitor resulted in the decrease of the ignition time in comparison with the previous ignitor, and confirmed the possibility of $N_2O$ decomposition with the high flow rate using the multi-stage catalytic-ignition system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.2
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• pp.157-166
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• 1985

The Purpose of this study are to investigate the characteristics of the flame behavior of gasoline-methanol blended fuels in spark ignition engine. Ionization probe were installed at the cylinder head and piston in order to measure flame speed. Other parameter such as engine performance, fuel consumption rate and exhaust gas were measured. The results were as follows. 1. In the case of increase methanol contents in blend fuel, flame propagation speed were increased, and thermal efficiency of the engine were increased due to decrease of energy consumption rate. 2. In the case of fixed equivalance ratio, NO sub(X) in exhaust gas were increased in accordance with increase of spark advance, and mean effective pressure were decreased in accordance with increase of methanol contents. 3. CO and HC concentration were decreased in accordance with increase of methanol contents.

• Fire Science and Engineering
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• v.13 no.2
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• pp.26-32
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• 1999

We had investigated combustion pro야$\pi$ies of rice bran dusts. Decomposition of rice bran d dusts with temperature were investigated using DSC and the weight loss according to t temperature using TGA in order to find the thermal hazard of rice bran dusts, and the p properties of dust explosion in variation of their dust with the same particle size. Using H Hartman's dust explosion apparatus which estimate dust explosion by electric ignition after m making dust disperse by compressed air, dust explosion experiments have been conducted by v varying concen$\sigma$ation and size of rice br뻐 dust. According to the results for thermodynamic stability of rice bran dust, there are little change of initiation temperature of heat generation 때d heating value for used particle size. But i initiation temperature of heat generation decreased with high heating rate whereas d decomposition heat increased with particle size. Also, the explosion pressure was increased as t the ignition energy increased and average maximum explosion pressure was 13.5 kgv'cnt for 5 BJ/60 mesh and 1.5 뼈Ie미 dust concentration.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.213-216
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• 2009

In order to see the flame behavior in the gas turbine combustor, combustion test was performed by using sector combustor. Ignition test with torch ignition system was carried out at the various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with fixed air mass flow rate. In the test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet air velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.451-457
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• 2011

The main objective of this study is to investigate the variation in the ignition characteristics of coals as a function of moisture content in a laminar flow reactor (LFR) equipped with a fuel moisture micro-supplier designed by the Pusan Clean Coal Center. The volatile ignition position and time were observed experimentally when a pulverized coal with moisture was fed into the LFR under burning conditions similar to those at the exit of the pulverizer and real boiler. The reaction-zone temperature along the centerline of the reactor was measured with a $70-{\mu}m$, R-type thermocouple. For different moisture contents, the volatile ignition position was determined based on an average of 15 to 20 images captured by a CCD camera using a proprietary image-processing technique. The reaction zone decreased proportionally as a function of the moisture content. As the moisture content increased, the volatile ignition positions were 2.92, 3.36, 3.96, and 4.65 mm corresponding to ignition times of 1.46, 1.68, 2.00, and 2.33 ms, respectively. These results indicate that the ignition position and time increased exponentially. We also calculated the ignition-delay time derived from the adiabatic thermal explosion. It showed a trend that was similar to that of the experimental data.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.14-27
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• 2020

Differential scanning calorimetry and numerical analysis were performed to estimate the performance degradation and ignition characteristics of the pyrotechnic device due to aging. The reaction kinetics extracted from the calorimetry are implemented into the numerical simulation of the igniter and the pyrotechnic delay, subjected to natural, thermal, and hygrothermal aging conditions. Also, combustion experiments are conducted to confirm that aging due to moisture is a major cause of performance failure of the pyrotechnic device as shown from the present numerical simulations.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1203-1205
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• 1987

가솔린 엔진용 전자 제어 에뮬레이션 시스템은 엔진의 운전 상태를 알려 주는 각종 센서로 감지한 정보를 A/D변환기를 통해 마이크로프로세서에 입력시키고, 이 정보를 이용하여 운전 상태를 분석한 후 엔진이 푤요로 하는 연료량, 점화시기, 배기가스의 재순환량, 공회전수 등을 전자적으로 제어하여 엔진의 최적제어를 실현시킴으로서 연료소비율 및 배기가스 중 공해물질 함량을 감소시키기 위한 장치이다.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2002.05a
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• pp.151-156
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• 2002

중의적인 단어를 처리하는 방법에 대한 선행연구로, 첫째 문맥에 맞는 의미가 먼저 활성화된다는 가설과 둘째, 여러 뜻 중에 상대적인 빈도에 따라 많이 쓰이는 의미가 먼저 활성화되고, 그것이 문맥과 일치하지 않는다면, 다른 관련된 의미를 찾는다는 가설이 제기되었다. 마지막으로 문맥에 상관없이 모든 의미가 활성화 된 후 문맥을 고려하여 문맥에 적절한 의미를 선택한다는 가설이 있다. 본 연구에서는 '먹을', '감을' 등과 같이 2가지 의미의 품사가 다른 중의 어절과 '쥐어', '감어' 등과 같이 어절 문맥('어')이 주어진 어절의 의미 활성화가 어떻게 다른지를 조사하였다. 본 연구의 목적을 위해 점화어휘 판단 과제를 사용하였다. 실험 1의 결과는 SOA 150ms 조건에서 점화자극어절과 관련된 의미가 품사와 관련 없이 모두 활성화되었다. SOA 1000ms 조건에서는 상대적으로 많이 쓰이는 체언의 의미는 계속 활성화 되어 있는 반면, 용언의 의미 점화량은 감소하였다. 명칭성 실어증 환자인 SDK의 경우 SOA 150ms 조건에서는 일반인과 같은 형태소 처리특성을 보였으나 1000ms 조건에서는 달랐다. 다른 명칭성 실어증 환자인 BIS과 전반성 실어증 환자인 PSB는 SOA 150ms 조건과 1000ms 조건에서 일반인과 아주 다른 양상을 보였다. 이것은 실어증 환자의 타잎에 따라 형태소의 처리나 중의적인 의미 활성화가 일반인과는 다르다는 것을 보여준다. 실험 2에서는 어절 문맥이 있는 '먹어', '쥐어', '감어' 등과 같은 어절을 사용하였다. 실험 2의 결과는 SOA 150ms 조건일 때 어절문맥의 영향으로 용언의 의미만 촉진적 점화효과가 있었고, 체언의 의미는 활성화되지 않았다. 그러나 SOA 1000ms로 지연시켰을 때는 용언뿐만 아니라 체언의 의미도 촉진적 점화효과가 있었다. 실험 1과 2의 결과는 중의적인 한국어 어절의 경우에도 모든 의미가 활성화되나 어절 문맥이 존재할 때는 어절 문맥의 제약으로 어절 문맥에 맞는 한 가지 의미만 활성화된다는 것을 암시한다. 또한 이러한 결과는 한국어 어절이 분석된 형태가 아닌 어절 형태로 심성 어휘집에 저장되어 있다는 것을 암시한다. 실어증 환자의 경우 실험 1과 마찬가지로 환자의 수준이나 종류에 따라 다양한 반응을 보여주었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.11-17
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• 2011

In order to see flame behavior in the annular reverse gas turbine combustor, sector combustion test was performed. Ignition test by using torch ignition system was carried out at various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with constant air mass flow rate. In test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity. Test result shows that lean blow out limits are increased with air velocity. The highest blow out limit was found at the combustor inlet velocity of 65 m/s.