In this study, the effects of fuel injection pressure changed from 45 to 65 MPa on combustion and emission characteristics were investigated in a common rail direct injection (CRDI) diesel engine fueled with diesel and palm oil biodiesel blends. The engine speed and engine load were controlled at constant 1700rpm and 100Nm, respectively. The tested fuel were PBD20 (20 vol.% palm oil biodiesel blended with 80 vol.% diesel fuel). The main and pilot injection timing was fixed at 3.5°CA BTDC and 27°CA BTDC (before top dead center), respectively. The experimental results show that the combustion pressure and heat release rate increased. In addition, the indicated mean effective pressure (IMEP) and maximum combustion pressure increased with an increase of the fuel injection pressure. Hydrocarbon (HC), smoke opacity and carbon monoxide (CO) decreased, but oxides of nitrogen (NOx) emissions increased as fuel injection pressure increased.

In this study, we investigated the effects of diesel-palm oil biodiesel-ethanol blends on combustion and emission characteristics in a 4-cylinder common rail direct injection (CRDI) diesel engine at low idling operations. The engine speed and engine load was 750 rpm and 40 Nm, while the main and pilot injection timing was respectively fixed at 2 °CA before top dead center (BTDC) and 20 °CA BTDC. The experimental results showed that the cylinder pressure increased with the increasing of palm oil biodiesel ratio from 20% to 100%. In addition, the peak value of cylinder pressure increased by 4.35% compared with pure diesel fuel when 5 vol.% ethanol oil added to diesel oil. Because the palm oil biodiesel and ethanol are the oxygenated fuel, the oxygen content played an important role in improving combustion. Based on the high oxygen content of biodiesel and ethanol, their mixing with diesel fuel effectively reduced PM emissions but increased NOx slightly, while CO and HC had no significant changes.

In this study, the effect of various pilot injection timings on combustion and emission characteristics were investigated in a common-rail direct injection (CRDI) diesle engine fueled with diesel-ethanol blends. The engine speed and engine load were controlled at constant 1500rpm and 70Nm, respectively. The tested fuels were DE0 (pure diesel fuel), DE5 (5 vol.% ethanol blended with 95 vol.% diesel oil), DE10 (10 vol.% ethanol blended with 90 vol.% diesel oil) and DE15 (15 vol.% ethanol blended with 85 vol.% diesel oil). The main injection timing was fixed at 0°CA TDC (top dead center), while various pilot injection timings including 25°CA BTDC (before top dead center), 20°CA BTDC and 10°CA BTDC were selected as the experimental variable. The experimental results showed that various pilot injection timings had little effect on the peak value of cylinder pressure, but had great influence on the start of combustion. The peak value of heat release rate (HHR) increased with the increase of ethanol content. However, the peak value of HRR reduced as the pilot injection is delayed. The diesel fuel containing 10% ethanol had a highest peak value of combustion pressure compared with the others, while the pilot injection timing occurred at 25°CA BTDC. On the other hand, the exhaust emissions of DE10 was also the lowest compared with the others. In addition, with the increase of ethanol content in diesel the PM and NOx emissions reduced.

본 연구는 한국산 재래종 메밀가루를 40%, 70% 에탄올(발효주정)로 각각 처리하여 메밀 추출물을 제조하였고 이를 동결건조한 다음 고지방식이에 혼합하여 흰쥐에게 섭취시킨 후 나타나는 식이성 고지혈증의 개선효과를 확인하고자 하였다. 실험군은 정상대조군(NC), 고지방대조군(HFC), 고지방-40%에 탄올메밀추출물군(HF-40), 고지방-70%에탄올메밀추출물군(HF- 70) 4군으로 나누어 4주간 실험식이로 사육하였으며 실험 결과는 다음과 같다. 1. 실험동물의 식이섭취량과 체중증가량 및 사료효율은 실험군들 간에 유의적 차이를 보이지 않았다. 2. 실험동물의 장기 중간무게를 비교한 결과 정상대조군에 비해 고지방대조군에서 유의적으로 높았고 고지방대조군에 비해 HF-70군은 유의적으로 낮았고 (p<0.05) 정상대조군도 비슷한 수준이었다. 3. 혈중 GOT, GPT 수치는 정상대조군이 가장 낮았고 고지방대조군이 가장 높았으며 HF-40군과 HF-70군은 고지방대조군보다 낮은 경향을 보였다. 혈당 농도는 전체 실험군 중에서 HF-70군이 가장 낮은 경향을 보였다. 4. 혈중 중성지질 농도는 정상대조군에 비해 고지방대조군이 가장 높았고 정상대조군과 고지방대조군에 비해 HF-40군 이 유의적으로 낮았으며(p<0.05) 혈중 유리지방산 농도는 실험군 간에 유의적인 차이를 보이지 않았다. 5. 혈중 콜레스테롤 농도는 정상대조군에 비해 고지방대조군에서 유의적으로 높았고(p<0.05) 고지방대조군과 비교했을 때 HF-70군에서 낮은 경향을 보였으며, 혈중 유리콜레스테롤 농도는 실험군 간에 유의적인 차이가 없었다. 혈중 콜레스테롤에스터 수치는 정상대조군이 71.6mg/dl로 유의적으로 가장 낮았고 고지방대조군의 125.0mg/dl와 비교하여 HF-40군, HF- 70군은 각각 116.9mg/dl, 88.5mg/dl로 유의적으로 낮았다 (p<0.05). 특히 HF-70군은 HF-40군에 비해서도 유의하게 낮은 것으로 나타났다. 6. 혈중 LDL-콜레스테롤은 정상대조군에 비해 고지방대조군이 유의적으로 높았으며 고지방대조군(130.6mg/dl)에 비해 HF-70군(85.1mg/dl)에서 유의적으로 낮았다(p<0.05). 7. 혈중 HDL-콜레스테롤은 정상대조군에 비해 고지방식이군들이 유의적으로 낮았으며(p<0.05) 고지방실험군들 간에는 유의적인 차이가 없었다. 그러나 HDL-콜레스테롤/총콜레스테 롤의 비율은 정상대조군에 비해 고지방대조군이 유의적으로 낮았고 고지방대조군에 비해 HF-70군이 유의적으로 높았다 (p<0.05). 8. 동맥경화지수는 정상대조군이 가장 낮았으며 고지방대조군이 정상대조군에 비해 유의적으로 높았고 고지방대조군에 비해 HF-70군은 유의적으로 낮았다 (p<0.05). 본 실험에서 고지방식이를 섭취한 쥐의 이상지질혈증은 메밀 에탄올추출물에 의해 개선되었으며 40% 에탄올 메밀추출 물보다 70% 에탄올 메밀추출물에서 더욱 많이 개선되는 것으로 확인되었다.

본 연구는 식물공장에서 광 조사조건에 따른 아이스플랜트의 생육변화를 확인하고자 한다. 광조절을 통해 최적 생장 조건을 구명하고 식물공장 내부의 에너지 절감과 고부가가치 작물 개발을 통한 경제성 문제해결의 기초자료로 활용하고자 한다. 실험은 LED이용 식물공장에서 8개 베드에 각각 다른 광조건 을 처리하여 실험을 하였다. 실험구는 일일 광조사시간을 12시간, 16시간으로 하여 각각 4처리를 두었 으며, 동일한 명기를 지닌 4개의 실험구는 광의 On/Off처리를 하여 반복 실시하였다. 그 결과 아이스 플랜트 생육은 명기를 16시간으로 처리한 조건에서 12시간 처리에 비해 우수하였다. 동일한 명기 조건 내에서는 광의 On/Off처리를 반복 실시한 실험구에서 생육이 양호하였다. 아이스플랜트는 광 스트레스 에 의해 C3에서 CAM으로 광합성 경로를 전환하는 식물임에 따라 광의 On/Off처리가 계속적으로 광을 조사한 실험구에 비해 광 스트레스를 적게 받는 것으로 판단된다.

In this study, we investigated the effects of EGR rate and engine load on the emission characteristics in a 4-cylinder common rail direct injection diesel engine fueled with canola oil biodiesel (BD) blended fuel. The biodiesel blend fuel, BD20 (20 vol.% biodiesel and 80 vol.% ULSD blend) was used at an engine speed of 1,500rpm. The experimental results showed that with the increasing of EGR rate, the combustion pressure and rate of heat release (ROHR) of three test fuels were decreased, and the ignition delay was extended, the carbon monoxide (CO) and particulate matter (PM) emissions increased slightly, but the nitrogen oxide (NOx) emission decreased clearly. On the other hand, with the increasing of engine load, the combustion pressure and ROHR were increased, and the CO and PM emissions decreased. However, the NOx emission was increased due to the rise of the combustion temperature.

This study describes the effects of canola oil biodiesel (BD) blended fuel on the combustion performance and emission characteristics in a 4-cylinder common-rail direct injection diesel engine. In this study, with the increasing of engine loads, the biodiesel blend fuels(100 vol.% ULSD and 0 vol.% biodiesel blend, BD0; 80 vol.% ULSD and 20 vol.% biodiesel blend, BD20; 0 vol.% ULSD and 100 vol.% biodiesel blend, BD100; ULSD: ultra low sulfur diesel) were used at an engine speed of 1,500rpm. The experimental results showed that with the increasing of biodiesel blend rate, the combustion pressure decreased slightly at engine load of 20~60Nm. However, the rate of heat release (ROHR) increased clearly and ignition delay time was shortened. With the increasing of biodiesel blend rate, the carbon monoxide (CO) and particulate matter (PM) emissions were more decreased at all of the engine loads.

This study was performed to investigate the effect of fuel combustion enhancing apparatus(FCEA) for ionization of intaking air into cylinder combustion chamber on the combustion performance and emissions characteristics in a 4-cylinder common-rail direct injection diesel engine. The experiments were applied to the engine at an engine speed of 1,500rpm under 20Nm, 40Nm, 60Nm and 80Nm conditions. The test results were compared to each other with or without the FCEA. In the case of the FCEA, the combustion pressure, peak combustion pressure and rate of heat release were increased slightly and the brake specific fuel consumption(BSFC) was decreased slightly when compared to that without the FCEA under all loads at an engine speed of 1,500rpm. However, in the case of the FCEA, the nitrogen oxide(NOx) were increased slightly, the carbon monoxide(CO) and particulate matter(PM) were decreased slightly when compared to that without the FCEA under all loads at an engine speed of 1,500rpm.

이 연구는 6차 고등학교 공통과학 교과서의 내용 중 온실효과 개념에 대한 본문진술과 제시된 그림 및 도표들을 분석하고 오개념 유발과 관련하여 문제점을 지적하고 그 개선방안을 모색하였다. 과학교과서의 개념진술이 정확하지 않아 학습자들에게 오개념을 유발하거나 재강화 할 가능성이 있는 여러 진술문을 발견하였고 학생의 과학적 개념형성에 부족한 그림이나 도표들도 발견되었다. 이들은 온실효과의 주 역할 기체와 변화, 지구온난화, 에너지원, 실험, 물리적 과정, 온실기체와 관련된 것들이다. 이들 개념진술이나 그림, 도표를 대체할 개선방안들을 제시하였다.

정상사료내의 지질에 철분이 어떤 영향을 미치는가를 알아보기 위하여 정상사료(Common feed)와 물을 혼합한 비정상 사료내에 Vitamin E와 유리 불포화 지방산 함량을 측정한 결과 다음과 같은 성적을 얻었다. 1. 정상사료(P<.05)와 비정상사료(P<.01)내의 Vitamin E 함량은 1.75mg/g(실험 1일째) 로부터 0.25mg/g(실험 11일째)로 지속적으로 감소되었다. 2. 정상사료내의 유리 불포화 지방산 함량은 23.8mg/g(대조군)로부터 17.6mg/g(20% 철분 혼합군)로 역시 지속적으로 감소되었다(P<.01). 3. 비정상사료내의 유리 불포화 지방산 함량은 23.9mg/g(대조군)로부터 17.4mg/g(20% 철분 혼합군)로 지속적으로 감소되었다(P<.01). 4. 정상사료내의 Vitamin E와 유리 불포화 지방산 함량은 비정상사료내의 함량보다 다소 높았으나 유의차는 인정되지 않았다. 5. 정상사료와 비정상사료내의 Vitamin E와 유리불포화 지방산에 있어서 날짜 경과별 및 철분 혼합 수준별 간의 상호작용이 인정되었다.

Persimmon is a plant that is native to the Republic of Korea. It leaves are rich in antioxidants and minerals. This study set out to investigate the moisture, color, vitamin C, and mineral contents of five of the most common Korean persimmon leaves (‘Sangju-dungsi’, ‘Sangam-dungsi’, ‘Cheongdobansi’, ‘Gabjubaekmok,’ and ‘Suhong’), and how they varied with the applied drying technique (freeze-drying or hot-air drying at 100℃ for 30 min) and harvesting time (late May or late June). Persimmon leaves were first collected, and then blanched and dried. Our results revealed that freeze-drying was the most effective method in terms of the mineral content, while no significant difference in the vitamin C content was observed regardless of the drying method. The concentration of Mg, Ca, K, and Mn increased from May to June, while the opposite trend was observed for Na, Fe, Cu, and Zn. Persimmon leaves collected in late May had a higher vitamin C content than those harvested in late June. Ultimately, the ‘Sangam-dungsi’ persimmon leaf was found to have the highest mineral content, whereas ‘Gabjubaekmok’ leaves were richer in color (lightness, redness, and yellowness) and had the highest vitamin C content among the analyzed cultivars.