• Journal of ILASS-Korea
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• v.22 no.4
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• pp.190-196
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• 2017

The aim of this work is to investigate the combustion and exhaust emission characteristics of low-temperature combustion (LTC) at various EGR test conditions using a single cylinder common-rail diesel engine. In high EGR rate combustion mode with DME fuel, 30% (${\Phi}=0.61$) and 50% (${\Phi}=0.86$) of EGR were respectively examined, and then the combustion, exhaust emissions, nano-particle characteristics of each cases were measured. From these results, it revealed that The ignition delay and combustion duration are prolonged as the increase of EGR rate. In addition, at an advanced injection timing (BTDC $30^{\circ}$), ignition delays were fairly increased because the dilution effect of EGR and also low charge in-cylinder temperature created a lean mixture, thus decreased the peak release rate.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.221-232
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• 2012

Cycle analysis has been performed to find out the optimum design point of the BOG re-liquefaction plant. The cycle state, defined by three cycle variables, was mainly described by the three cold temperatures of the three-pass heat exchanger, on which the constraints by the heat exchanger are imposed. The cycle states which are confined within a domain limited by the temperature constraints were the primary issue of this study. The BOG mass within the domain was analyzed first and then the cycle performance was related to the BOG mass afterwards, which enabled us to explain the observed behavior of the cycle performance under the temperature constraints by the heat exchanger. A good cycle performance could be ensured if the two cold Nitrogen temperatures of the three temperatures were placed close together near $-140^{\circ}C$ while the BOG temperature is kept far above enough, but not too far, from $-140^{\circ}C$ such that it does not interfere in their optimum temperature range.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.89-94
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• 2011

In recent years there have been considerable attentions on nanoimprint lithography (NIL) by the display device and semiconductor industry due to its potential abilities that enable cost-effective and high-throughput nanofabrication. A major disadvantage of thermal NIL is the thermal cycle, that is, heating over glass transition temperature and then cooling below it, which requires a significant amount of processing time and limits the throughput. One of the methods to overcome this disadvantage is to improve the cooling performance in NIL process. In this paper, a numerical analysis model of cooling system in thermal NIL was development by CAD/CAE program and the performance of the cooling system was analyzed by the model. The calculated temperatures of nanoimprint device were verified by the measurements. By using the analysis model, the case that the cooling material is replaced by liquid nitrogen is investigated.

• Journal of Powder Materials
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• v.13 no.1 s.54
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• pp.10-17
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• 2006

Model experiment was introduced to obtain the formation of a core/rim structure by only liquid phase reaction in Ti(C, N)-based cermet alloys. Infiltrated Ti(C, N)-Ni, $MO_2C-Ni$, and TaC-Ni cermets were bonded to sandwiched specimen by heat treatment $1450^{\circ}C$ for 5hr. With nitrogen addition, both (Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim structure was nucleated around comer of cuboidal Ti(C, N) core. However, equilibrium shapes of(Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim were different possibly due to the effect of interface energy. The core/rim and rim! binder interfaces were parallel to each other with TaC addition, while rotated to each other with $MO_2C$ addition.

• Preventive Nutrition and Food Science
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• v.4 no.2
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• pp.103-106
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• 1999

Fish sauce is a liquid form of salt-fermented fish and has played an important role in Korean dietary life. Fish sauce was manufactured by utilizing Alaska pollack scrap from Himedara(seasoned and dried Alaska pollack tail) processing . In addition, the effects of squid viscera as a fermentation enhancer were also evaluate.Ph of Alaska plllack scrap sauce with squid viscera was lower than that of control over the entire fermentation process. Squid viscera acceleraged the production of amino-nitrogen, VBN , TBA and free amino acids, and the degradation of IMP and Inosine. The addition of squid viscera and koji at 5% concentration, respectively , also accelerated the digestion of Alaska pollack scrap and was similar to the results of squid viscera at 10% concentration.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.352-354
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• 2010

The effects of Au addition on the structure and the superconducting properties of Bi system bulk have been investigated. Au exists in the metalic form in above materials. It does not affect the formation and structure of the BiSrCaCuO(2223) phase. The superconducting transition temperature Tc does not change for $Bi_{1.7}Pb_{0.3}Sr_2Ca_2Cu_3O$ composite However Au doping can make the grains smaller. Metallic Au can make gathers on the grains boundary and lead to the increment of critical transport current density. The current density of $Bi_{1.7}Pb_{0.3}Sr_2Ca_2Cu_3Au_{0.5}O$ was 1000A/$cm^2$ at liquid nitrogen temperature.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1992-1994
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• 2007

In this paper we propose a cryogenic sensor system which can measure the temperature at higher resolution at low temperature using temperature-dependent amplified spontaneous emission of erbium-doped fiber pumped by a 1480 nm laser diode. The measurement resolution of the sensor system could be enhanced through the modulation of injection current of the pump laser diode. The measurement resolution considering the fluctuation of the light source in the sensor system was ${\sim}0.4$ K in the room temperature regime and ${\sim}0.07$ K in the liquid nitrogen temperature regime.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.237-239
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• 2003

A high-temperature superconductor (HTS) journal bearing was studied for loss. Two HTS bearings support the rotor at top and bottom. The rotor weight is 4 kg and the length is about 300 mm. Both the top and bottom bearings have two permanent magnet (PM) rings with an iron pole piece separating them. Each HTS journal bearing is composed of six pieces of superconductor blocks of size 35$\times$25$\times$10 mm. The HTS blocks are encased in a cryochamber through which liquid nitrogen flows. The inner spool of the cryochamber is made from G-10 to reduce eddy current loss, and the rest of the cryochamber is stainless steel. The magnetic field from the PM rings ＜ 10 mT on the stainless part. The rotational drag was measured over the same speed range. Results indicate that the 10 mT design criteria for magnetic field on the stainless part of the cryochamber is too high.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.213-217
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• 2003

In this paper, we studied electric Insulation characteristics of synthetic Laminated Polypropylene Paper (LPP) in liquid nitrogen (L$N_2$) for the application to high temperature super-conducting (HTS) cable. And, we selected the insulation paper/L$N_2$composite insulation type for the electric insulation design of a HTS cable. Furthermore, we compared the breakdown characteristics of the butt gap and bended mini-model cable that comes into being in this kind of cryogenic insulation type. It is necessary to understand the winding parameter of insulation paper/L$N_2$composite insulation.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.69-71
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• 2003

The magnetic field sensor was fabricated with superconducting ceramics of YBaCuO system. The sensor at liquid nitrogen temperature showed the increase of electrical resistance by applying magnetic field. Actually the voltage drop across the sensor was changed from zero to a value more than 100 $mutextrm{V}$ by the applied magnetic field. The change in electrical resistance depended on magnetic field. The sensitivity of this sensor was 2.9 $\Omega$/T. The sensing limit was about $1.5\times$10$^{-5}$. The increase of electrical resistance by the magnetic field was ascribed to a modification of the Josephson junctions due to the penetrating magnetic flux into the superconducting material. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.