• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.64-68
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• 2003

For the purpose of the efficient derivation of the closed-form Green's functions by which MoM matrix elements can be analytically evaluated, the optimum approximation path which is deformed from the Sommerfeld integration path on the complex $k_{\rho}$-plane is proposed based upon the steepest descent method and three level approximation procedure.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.835-840
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• 2000

The objective of the present study is to investigate the characteristics of pressure wave propagation of viscous fluid flow in a circular pipe line. The goal of this study is to select the best frequency of each control factor of a circular pipe. We intend to approach a formalized mathematical model by a very exact and reasonable polynomial for fluid transmission lines. and we computed this mathematical model by computer. The results show that the oil viscosity decreased as the length of the circular pipe increases. and The energy of pressure wave propagation decreased as the pipe diameter decreases. The factor is that density of oil was changed resonant frequency. It has been found the viscosity characteristics is changed largely by length of hydraulic pipe and volume of cavity tank.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.185-187
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• 2006

본 논문은 신 발전 방식들 중 하나인 용융탄산염형 연료전지 발전시스템의 국산화연구와 관련하여, 연료전지로부터 생성된 전력을 전력계통에 안정되게 변환, 주입하기 위한 계통연계형 전력변환기를 제작하고 단위기기별 성능 시험을 수행한 결과이다. 250kW급 전력변환기의 구조 설계와 단위기기 설계는 250kW급 용융탄산염형 연료전지 시스템의 정격 사양 및 스택의 운전 형태를 시뮬레이션 하여 진행되었으며, 크게 DC/DC 컨버터부와 DC/AC 인버터부의 회로로 구성된다.

• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.97-100
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• 1997

Cyclodxtrin homologues(CDs), produced by cyclodextrin glycosyltransferase(CGTase), were simultaneously partitioned in aqueous two-phase system(ATPS). Partition coefficients of CDs were measured in PEG/dextran systems. Phosphate, citrate, sulfate were tested as salt. ATPS of PEG/salt and PEG/dextran had the partition coefficients of the CDs, larger than unity. However, PEG/dextran system was observed better than PEG/salt as CGTase activity decreased sharply with salt concentration. Enzymatic rection occurred mainly in PEG-rich bottom phase because of the low partition coefficient of CGTase. The resulting CDs transferred to the PEG-rich top phase, obeying the diffusional partition. In the ATPS of 7% PEG(M.W.40, 000), 7mg/ml of CDs were obtained in top phase at 4.5 hours.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.689-693
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• 2005

Different masking materials were evaluated for their ability to ameliorate odor of model poultry manure solution by assessing their effects on sensory pleasantness and odor intensity. Results indicated extracts from Eastern red cedar leaves, Loblolly pine needles', and commercial masking agents such as pine extract and odor neutralizer were effective (p<0.05) for masking odor of model poultry manure solution by increasing (p<0.05) pleasantness (82 and 86% increases in pleasantness using red cedar and pine needle extracts, respectively) and decreasing (p<0.05) odor intensity (odor intensity reduction by 66 and 76% using red cedar pine needle extract). The most odor-active compound in Loblolly pine needle extract was ${\alpha}$-terpineol (1,573.8 ug/g) which is responsible for aroma of pine trees (piney) and effective for ameliorating agricultural odors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.1-1
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• 2014

Side scuttle in the shipboard windows is used in a smaller size in order to prevent damage to the glass. This shipboard windows should have high sound insulation performance (More than $R_w$ 53 dB) according to norsok standards. However, side scuttle having a small size and high sound insulation material is difficult to measure exact result without a suitable filler wall. In this study, the test was conducted according to the number of changes in the small window. As a result, before starting the test should be conducted to the selection of the suitable filler wall or secure a specimen area.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.209-209
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• 2008

• Journal of Powder Materials
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• v.7 no.2
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• pp.78-84
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• 2000

P/M high speed steels(1.28% C, 4.20% Cr, 6.40% W, 5.00% Mo, 3.10% V, bal. Fe) from two different venders were applied to powder compacting punch. The test results show that failure lifes were very different between two punches. These were no difference in volume fraction and mean size of carbides(MC or M6C) but non-metallic inclusions in two punches. Small amount of non-metallic inclusion in the punch did not greatly affect impact energy and transverse rupture strength (TRS). But, fatigue life was drastically decreased by non-metallic inclusions. These results show that fatigue failure was initated around non-metallic inclusion by cyclic load and the fatigue life was greatly affected by the presence of non-metallic inclusions in the punch.

• Journal of Powder Materials
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• v.14 no.6
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• pp.367-371
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• 2007

P/M high speed steel (1.26% C, 4.42% Cr, 6.54% W, 4.92% Mo, 3.21 % V, 8.77% Co, bal. Fe) was applied to hot former die. It showed that the die life became 2.7 times higher than that of cast/wrought SKH 55 tool steel which is commercially used. The increase of die life was corresponding to the improved hardness and transverse rupture strength of PM high speed steel due to the finer grain and carbide as well as the uniform carbide distribution. The P/M high speed steel with the promoted die life could be an alternative to the conventional SKH55.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.178-178
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• 2012

CIGS 단일 타켓을 RF 마그네트론 스퍼터링을 이용하여 파워별(20. 40, 60, 80W)로 Mo/SLG 위에 증착하여 열처리를 실시하였다. 파워 증가에 따라서 박막의 결정성은 이온의 운동에너지 증가에 따라서 결정성이 향상될 것을 예상할 수 있다. 그리고 1step $350^{\circ}C$, 1step $550^{\circ}C$, 2step $350^{\circ}C{\sim}550^{\circ}C$, 3가지 열처리 조건를 실시했을 경우 각 각의 열처리 방법에 따라서 결정성이 달라지는 것을 확인 할 수 있었다. 1step으로 열처리를 실시한 경우 보다 2step의 열처리를 실시 한 경우가 결정성이 더 향상되는 것으로 예상된다.