• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.159-162
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• 1998

불발 음원에 따른 음원 배열의 빔 패턴 변화와 남극탐사자료에서 원거리장 파형 변화를 분석하였다. 원거리장 파형의 주신호 진폭은 전체 건 부피의 약 40%에 해당하는 음원들이 불발을 일으킬 경우, 탐사성능이 33% 정도 떨어지는 것으로 확인되었다. 같은 간격의 음원들이 불발 시에는 배열형태와 관계없이 길이 및 폭배열의 빔 폭이 동일하게 나타난다. 불발 음원의 부피가 증가됨에 따라 상대적으로 음파 에너지가 작아 지지만 빔 폭이 40$^{\circ}$ - 34$^{\circ}$로 좁아지는 경향을 나타낸다. 따라서 탄성파 탐사에서 필요로 하는 좁은 파형이 생성됨으로써 천부 지층탐사에 적합한 것으로 확인되었다.

• The Journal of the Acoustical Society of Korea
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• v.18 no.7
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• pp.75-79
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• 1999

The beam patterns of source array and changes in the far-field signatures are compared and analyzed each other in order to identify the seismic capability affected by the misfired source at the multi-channel seismic source array. In the primary pulse amplitude of far-field signature, the 66% of seismic capacity are sustained if approximately 40% of source are misfired among whole gun volume. When the sources with the same distances are misfired at the 154㎐, the beam width of the long- and wide-array which is identical regardless of arraying pattern. The beam width has a tendency to narrow now from 41 to 34 according to increase the volume of misfired source at the long-array beam pattern. Therefore, the source array of small volume are suitable for the shallow seismic survey because of producing adequate beam patterns with narrow beam width.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.700-707
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• 2016

Recently, ammunition malfunctions of the 40mm grenade were reported during live fire training. When 72 40mm grenades were fired by the army, 11 duds were encountered. The dud ammunition rate was approximately 15%. Because ammunition is used a long time after its manufacture, it is necessary to ensure its performance after long-term storage. In this study, we attempted to decrease the dud ammunition rate of 40mm grenade (K200) fuzes through quality improvement. First, it was determined by the detonator performance test that abnormal explosions occurred due to the degradation of the detonator as a result of its aging characteristics. Second, we improved the fuze quality of the 40mm grenade. Third, we tested its shelf life to estimate its life expectancy. The shelf life of the 40mm grenade fuze obtained using the Arrhenius equation was 6.5 years for the existing grenade fuze and 45.5 years for the improved grenade fuze. This showed that the shelf life of the improved grenade was increased approximately 7 times. Therefore, the improved 40mm grenade fuze contributes to the quality improvement of the 40mm grenade by decreasing the dud ammunition rate during long term storage.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.1-5
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• 1965

The purpose of this work is to investigate the effects of picking leaves in autumn on the non-budding and survival of grafting. The results are as follows. 1) The leaf picking in autumn causes an increase of the non-budding ratio in the following spring. When tue whole leaves picking is compared with the control, the non-budding ratio increases 46 percent. In case of tone leaves on a single stem are picked in various tray, the non-budding ratio of picked portion is higher than that of non-picked. 2) The leaf picking in autumn with winter bud being grafted on stock in the next spring, decrease the survival of grafting. In case some leaves on a single stem are picked in various way, the winter bud of picked part is always poor in survival. 3) In the event of leavf picking in autumn, the yield always decreases 7∼20 percent, especially this phenomenon becomes serious in the under half part of the stem(20%) and whole leaves picking(12％) treatments.

• Aerospace Industry
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• v.35
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• pp.66-69
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• 1996

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.328-334
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• 2020

At the recent practice test of the Remote Controlled Munition system (for practice), nine out of 125 samples were generated. Although 7.2 % misfires occurred, the acceptance test met the defense standards. Minimizing the probability of broken fuses is essential to reducing the number of samples and improving the AQL according to the process quality. In addition, it is necessary to increase military training and ensure user safety. In the case of practical grenades, hit-type detonators are applied. Unlike the normal design, which takes a hit by strikers, a different design of a hit by pressure from a pressure generator was used. This study analyzed the detonator surface through computational fluid dynamics. The results showed that the probability of functional weakness and retraction increased with increasing slope of the detonator surface. To overcome this, design changes were made to improve the fuse crimping process and increase the detonator holder seat. A performance test with the same number of samples from the whole quantity was operated. The probability of broken fuses was 0 %. Therefore, the reliability and performance of the ammunition can be improved and is expected to contribute to the drawing and process design when developing similar ammunition.

• Proceedings of the KSEE Conference
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• 2008.10a
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• pp.119-127
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• 2008

불꽃놀이는 한국명 연화(煙火), 중국명 폭죽(爆竹), 일본명 하나비(花火), 영어명 파이어웍스 디스플레이(Fireworks display) 표기되며 화약류를 연소 폭발시켜서 빛, 소리, 형태, 연기, 연막, 시간지연, 운동에너지 등을 조합하여 예술적인 감각을 연출시키는 공학으로써 공예술학으로 불랴는 일종의 예술작품이다. 우리나라의 연화기술은 세계적이다. 1980년대에 개발이 완료되었고, 1990년대에 완숙단계흘 거쳐 향후 2010년 이후에는 환경안전을 고려한 최첨단 나노 생명공학으로 발전하여야 할 것이다. 즐거운 불꽃축제 후에 환경오염방지 대책과 비상체제 운영능력, 저장소관리, 불발탄 및 폐기물처리, 시민의식 향상 등이 더욱 요망된다. 본 논문은 올해 제4회를 맞는 부산불꽃축제를 중심으로 현황 및 발전방향과 개선안을 제시하였다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.3
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• pp.367-372
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• 2008

Yukwa were added with non-fermented tea (Bucho-cha and Okro-cha), semi-fermented tea (Ooreung-cha), and fermented tea (black tea) to investigate the effect of different kinds of tea powder on quality characteristics of Yukwa during storage. Yukwa samples were used for analysis such as crude lipid, moisture, texture, antioxidative property (TBA value), and sensory test. There were no significant differences on crude lipid, moisture, and texture analysis. Green tea powder treatment showed strong antioxidant activity. In particular, antioxidant property of non-fermented tea exhibited a higher antioxidative effect than that of the other samples. Sensory evaluation showed that sensory scores of samples added with non-fermented tea were significantly higher than the other samples, indicating that the addition with 0.1% of non-fermented tea powder could contribute to the improvement of quality and shelf-life of Yukwa during storage.

• Food Science and Preservation
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• v.13 no.5
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• pp.596-602
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• 2006

This study was conducted to investigate the changes of major components and bioactivities of tea produce. The tea produce were made by various methods, with different degree of fermentation during manufacturing process. Except green tea, degrees of fermentation in Wizo Tea, Ilsoae Tea, and Hwang Tea were $5{\sim}10%,\;50{\sim}60%$ and $70{\sim}80%$ respectively. The result are as follows : The general component(moisture, crude ash, crude lipid, and crude protein) and the content of total polyphenol in tea products were not shown significant difference during the fermentation process. The content of caffeine in tea extracts decreased sharply as degree of fermentation of tea. In comparison of hunter values in tea extract, lightness was decreased as fermentation redness (a) was all (-), and yellowness(b) was increased sharpy with degree of fermentation. Radical scavenging activity using DPPH of tow kinds of tea was potent and decreased generally with degree of feimentation. Inhibitory effects of tea extracts against angiotensin I converting enzyme were also potent.

• 프린팅코리아
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• s.5
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• pp.198-203
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• 2002

차는 그 탁월한 색향미와 효능으로 인해 이미 오래전부터 세계인의 음료로 사랑받고 있다. 유럽에 차가 전해진 것은 16세기의 일이지만 동양에서는 BC3,000경부터 차를 마셔왔으며, 차생활을 중심으로 동양 특유의 문화가 피어났다. 따라서 동양문화는 차를 이해하지 못하면 제대로 접근하기 어려운 특성을 가지고 있다. 유럽이나 미국에서는 발효차인 홍차가 주종을 이루고 있으나 동양에서는 불발효차인 녹차를 즐긴다.