• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.46-53
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• 2004

Heat release analysis is a very important method for understanding the combustion phenomena inside an engine cylinder. In this study, one-zone heat release analysis was used with the measured cylinder pressures of a HSDI(high speed direct injection) and IDI(indirect injection) diesel engines, Those have benefits of simple equation, fast speed, reliability. The objective of the study is to compare the combustion characteristics between a HSDI and an IDI. The result shoes that the maximum heat release rate of a HSDI is higher than that of an IDI because of long ignition delay period. The heat release curve of an IDI is more linear than that of a HSDI, thus is similiar to that of a SI engine. The combustion efficiency of a HSDI is higher than that of an IDI because of the smaller heat transfer loss of a HSDI. There is a suggestion here that an IDI engine has broad heat transfer area which include two combustion chambers, the connection passage of combustion chambers, etc.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.21-30
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• 2005

Heat release analysis is a very importent method in understanding the combustion phenomena inside an engine cylinder. In this study, one-zone heat release analysis was used with the mesured cylinder pressures of an IDI(indirect injection), a HSDI(high speed direct injection) and a SI(spark ignition) engine. It has benefits of simple equation, fast speed, reliability. The object of the study is to compare the combustion characteristics among an IDI, a HSDI and SI engine. Result of analysis, the maximum heat release rate of a HSDI is higher than an IDI because of long ignition delay period. The heat release curve of a IDI is more linear than an HSDI, so the combustion characteristics of a IDI is similiar to that of an SI engine. There is a suggestion here that the combustion efficiency of a HSDI is highest of that of all engines because of the smallest heat transfer loss of all engines.

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.526-530
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• 2010

Isopentenyl diphosphate(IPP) isomerization to dimethylallyl diphosphate(DMAPP) is an important step for the efficient production of isoprenoids such as lycopene, ${\beta}$-carotene, astaxanthin, etc. The type II isopentenyl diphosphate isomerase gene from Synechocystis sp. PCC6803(sll1556, Syidi2) was cloned and expressed in Escherichia coli $DH5{\alpha}$. When E. coli $DH5{\alpha}$ harboring lycopene synthesis genes, crtE, crtB, and crtI and mevalonate pathway genes, MvK1, MvK2, and Mvd, was cultured on LB medium containing mevalonate, the strain grew very slowly be due to the toxicity of isopentenyl diphosphate derived from mevalonate. When Syidi2 was introduced to E. coli $DH5{\alpha}$ harboring the lycopene synthesis genes and mevalonate pathway genes, growth on mevalonate medium was fully restored and the colony showed red color indicating lycopene formation. The growth rate of the mutant strain, E. coli $DH5{\alpha}$(idi::${\Delta}km$), was very slow because of IPP accumulation and DMAPP deprivation. Ultimately the idi mutant was complemented by introducing the Syidi2 gene.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.75-80
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• 2008

Biodiesel fuel(BDF) can be effectively used as an alternative fuel in diesel engine. However, BDF may affect the performance and exhaust emissions in diesel engine because it has different physical and chemical properties from diesel fuel such as viscosity, compressibility and so on. To investigate the effect of injection timing on the characteristics of performance and exhaust emissions with BDF in IDI diesel engine, it was applied the BDF derived from soybean oil in this study. The engine was operated at seven different injection timings from TDC to BTDC $12^{\circ}CA$ and six loads at a single engine speed of 1500rpm. When the fuel injection timing was retarded, better results were showed, which may confirm the advantages of BDF. The simultaneous reduction of smoke and NOx was achieved at some fixed fuel injection timings of an IDI diesel engine.

• Mycobiology
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• v.51 no.3
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• pp.169-177
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• 2023

To further explore the molecular mechanism of triterpenoid biosynthesis and acquire high-value strain of Sanghuangporus baumii, the Agrobacterium tumefaciens-mediated transformation (ATMT) system was studied. The key triterpenoid biosynthesis-associated gene isopentenyl diphosphate isomerase (IDI) was transformed into S. baumii by ATMT system. Then, the qRT-PCR technique was used to analyze gene transcript level, and the widely targeted metabolomics was used to investigate individual triterpenoid content. Total triterpenoid content and anti-oxidant activity were determined by spectrophotometer. In this study, we for the first time established an efficient ATMT system and transferred the IDI gene into S. baumii. Relative to the wild-type (WT) strain, the IDI-transformant (IT) strain showed significantly higher transcript levels of IDI and total triterpenoid content. We then investigated individual triterpenoids in S. baumii, which led to the identification of 10 distinct triterpenoids. The contents of individual triterpenoids produced by the IT2 strain were 1.76-10.03 times higher than those produced by the WT strain. The triterpenoid production showed a significant positive correlation with the IDI gene expression. Besides, IT2 strain showed better anti-oxidant activity. The findings provide valuable information about the biosynthetic pathway of triterpenoids and provide a strategy for cultivating high-value S. baumii strains.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.33-42
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• 2021

Modern aircraft fighters improve the maneuverability and performance with the RSS (Relaxed Static Stability) concept and therefore these aircrafts are susceptible to abrupt pitch-up in the transonic and moderate Angle-of-Attack (AoA) flight region where the shock wave is formed and the mean aerodynamic center is moved forward during deceleration. Also, the modeling of the aircraft flying in this flight region is very difficult due to complex flow filed and unpredictable dynamic characteristics and the model-based control design technique does not fully cover this problem. In this paper, we analyzed the performance of the TPMC (Transonic Pitching Moment Compensation) control based on the model-based IDI (Incremental Dynamic Inversion) and the Hybrid IDI based on the model and sensor based IDI during the SDT (Slow Down Turn) in transonic region. As the result, the Hybrid IDI had quicker response and the same maximum g suppression performance and provided the predictable flying qualities compared to the TPMC control. The Hybrid IDI improved the performance of the Over-G protection controller in the transonic and moderate AoA region

• Journal of the Korea Society for Simulation
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• v.20 no.2
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• pp.1-10
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• 2011

In queueing network analysis, arrival processes are usually modeled as renewal processes by matching mean and variance. The renewal approximation simplifies the analysis and provides reasonably good estimate for the performance measures of the queueing systems under moderate conditions. However, high variability in arrival process or in service process requires more sophisticated approximation procedures for the variability parameter of departure/arrival processes. In this paper, we propose an heuristic approach to refine Whitt's variability function with the k-interval squared coefficient of variation also known as the index of dispersion for intervals(IDI). Regression analysis is used to establish an empirical relationships between the IDI of arrival process and the IDI of departure process of a queueing system.

• International Journal of Automotive Technology
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• v.8 no.2
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• pp.179-184
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• 2007

In this study, the potential use of oxygenated fuels such as ethylene glycol mono-normal butyl ether (EGBE) was investigated in an attempt to reduce the emission of exhaust smoke from diesel engines. Effects of the combustion method on exhaust emission of DI and IDI diesel engines were also examined. Since EGBE is composed of approximately 27.1% oxygen, this is one of several potential oxygenated fuels that could reduce the smoke content of exhaust gas. EGBE blended fuels have been proven to reduce smoke emission remarkably compared to the conventional commercial fuels. The test was conducted with single and four cylinder, four stroke, DI and IDI diesel engines. The study showed that a simultaneous reduction of smoke and NOx emission could be achieved by the combination of oxygenated blend fuels and the cooled EGR method in both DI and IDI diesel engines. It was also found that a reduction rate of exhaust emission in a DI engine was larger than an IDI diesel engine.

• Journal of Life Science
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• v.24 no.7
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• pp.762-768
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• 2014

Diet exerts a major stress on the body and may affect gene expression and physiological functions. Understanding of cellular responses during starvation is necessary in developing strategies to reduce damage caused by diet. In this study, we isolated 10 genes (Comt, RGN, Scd1, Temt, Idi1, Fabp5, Car3, Cyp2c70, Pinx1, and Poldip3) that are down-regulated in starvation and are closely related to liver metabolism. Water supply during starvation had no effect on the induction of apoptosis, autophagy, and ERQC. The genes down-regulated by starvation were associated with many related pathways rather than limited to the liver homeostasis pathway. Water supply during starvation is important. However, maintaining NaCl homeostasis is more important. The results are thought to be closely related to gender-specific metabolism in starvation and NaCl.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.2
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• pp.2-8
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• 1988

중대형 상용차에 널리 사용되어온 디젤엔진은 오일 쇼크 이후로 소형 상용차에까지 널리 탑재되고 있는 세계적인 추세이다. 디젤엔진은 높은 연소 압력 및 압력 상승율(Rate of Pressure Rice)로 운전되기 때문에 연소소음(Combustion Noise) 및 기계소음(Mechanical Noise)이 매우 크다. 차량 개발 개념에 있어 소음제어는 법적 규제와 소비자의 요구수준을 만족시키는 측면에서 고려되어야 한다. 차량 전체 소음에서 엔진 소음의 기여도는 약 40-50%정도이며 당연히 엔진소음 저감 대책의 필요성은 높다. 본고에서는 2.4리터 간접 분사식(IDI)디젤 엔진의 소음 저감을 위한 소음 저감 대책을 기술한다.