• 한국응용과학기술학회지
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• 제34권4호
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• pp.962-973
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• 2017

대기오염에 대한 관심은 국내 외에서 점진적으로 상승하고 있으며, 자동차 및 연료 연구자들은 청정(친환경 대체연료) 연료와 연료품질 향상 등을 이용하여 새로운 엔진 설계, 혁신적인 후처리 시스템 등의 연구를 통하여 차량 배기가스 및 온실가스를 감소시키고자 노력하고 있다. 이에 본 연구에서는 각기 다른 차량기술이 적용된 휘발유, 경유, LPG를 연료로 사용하는 7대의 차량을 대상으로 국내 외에서 법적시험모드로 사용되고 있는 도심모드, 고속모드, 급가 감속, 에어컨사용 및 겨울철 특성을 반영한 저온모드에서 온실가스의 배출특성을 확인하고자 하였다. 사용연료에 관계없이 대부분의 온실가스는 저온인 Cold FTP-75 모드에서 가장 안 좋은 결과가 나타나는 경향을 가지고 있다. 각 차량별 온실가스 증가 요인으로는 가솔린 차량인 A차량(2.0 MPI)과 B차량(2.4 GDI)에서는 최고속 및 급가 감속, 에어컨 사용, 저온 조건의 순인데 비해 E차량(1.6 T-GDI)은 에어컨 사용, 최고속 및 급가 감속, 저온 조건의 순이다. G차량(LPLi)은 에어컨 사용, 저온, 최고속 및 급가 감속 조건의 순으로 가솔린 차량과 다른 특성을 가지고 있다. 경유 차량에 있어서는 A차량(2.0 w/o DPF)과 B차량(2.2 w/ DPF)은 최고속 및 급가 감속, 에어컨 사용, 저온 조건의 순이었고, F차량(1.6 w/ DPF)은 저온, 에어컨 사용, 최고속 및 급가 감속 조건의 순으로 확인되었다. 따라서, 각 연료별로 배출가스 저감 기술을 다르게 적용하여야 효과적인 방법이라고 할 수 있겠다.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.87-93
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• 2007

It is complicate to analysis the systems, dual mode hybrid systems, because they are composed of many planetary gear sets. For the performance test, it needs to define the systems with representative parameters. In this paper, system parameters, $\alpha$, $\beta$, $\zeta$, are introduced to define the systems, and an arbitrary system like E-IVT developed by Renault Motors is converted to the general system having equivalent parameters, such as $\beta'$, $R'_b$. Pontryagin principle and Kuhn-Tucker condition method are applied to solve the constrained problems, by which the methodology for accelerating test is generalized, and the results of the simulation are reported. In addition, the effects of alternative strategies are mentioned. The method of fuel economy test at engine mode is also introduced. The results of test at engine mode is different from the results of optimal trajectory, but the fuel economy of the engine mode is related to the highway driving and optimized operating of the system.

• 한국통신학회논문지
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• 제35권11B호
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• pp.1667-1675
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• 2010

본 논문에서는 무선 휴대 장치의 전력공급을 위해 적용 가능한 고효율 PWM/PFM 모드 DC-DC벅 변환기를 제안한다. 휴대성 확보를 위한 간소화된 보상회로를 사용하고, 휴대장치의 대기 모드 및 저부하에서 높은 효율을 갖도록 설계하였다. 휴대 장치 동작 시간의 대부분을 차지하는 대기모드(저부하: 60mA이하) 및 저부하에서의 고효율 동작을 해서 PFM 동작 모드의 제어를 위해서 상대머신을 설계하였다. 칩 측정 결과 동작모드별로 PWM은 93%, PFM은 92.3%의 최대효율을 확인하였다. 측정된 출력 리플전압은 10mV 이하로 나타났다. 제안된 벅 변환기는 $0.35{\mu}m$ CMOS 공정으로 제작하였으며, 3.3V ~ 2.5V의 입력전압을 받아서 1.8V의 전압을 출력하였다.

• 소성∙가공
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• 제31권1호
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• pp.29-38
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• 2022

Recently, the composite material market is gradually growing. Various composite forming processes have been developed in order to reduce the production cost of the composite material. Unlike the conventional forming process, the microwave composite forming process has the advantage of reducing the processing time because the composite material is heated directly or indirectly at the same time. Due to this advantage, in this study, a double cantilever beam test was conducted with specimens manufactured by the microwave composite forming process. The purpose of this study was to compare mode-I energy release rate for specimens manufactured by prepreg compression forming and microwave composite forming processes. First, a microwave oven was proposed to conduct the microwave composite forming process. Double cantilever beam specimens were manufactured. After that, the double cantilever beam test was conducted to obtain the mode-I energy release rate. Mode-I energy release rates of specimens manufactured by the microwave composite forming and prepreg compression forming processes were then compared. As a result, mode-I energy release rates of specimens fabricated by the microwave composite forming process were similar to those fabricated with the prepreg compression forming process with a relatively reduced process time.

• Journal of Photoscience
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• 제9권2호
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• pp.90-93
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• 2002

Phytochrome A (phyA) and phytochrome B (phyB) perceive light and adapt to fluctuating circumstances by different manners in terms of effective wavelengths, required fluence and photoreversibility. Action spectra for induction of seed germination and inhibition of hypocotyl elongation using phytochrome mutants of Arabidopsis showed major difference. PhyA is the principal photoreceptor for the very low fluence responses and the far-red light-induced high irradiance responses, while phyB controls low fluence response in a red/far-red reversible mode. The structural requirement of their bilin chromophores for photosensory specificity of phyA and phyB was investigated by reconstituting holophytochromes through feeding various synthetic bilins to the following chromophore-deficient mutants: hy1, hyl/phyA and hyl/phyB mutants of Arabidopsis. We found that the vinyl side-chain of the D-ring in phytochromobilin interacts with phyA apoprotein. This interaction plays a direct role in mediating the specific photosensory function of phyA. The ethyl side-chain of the D-ring in phycocyanobilin fails to interact with phyA apoprotein, therefore, phyA specific photosensory function is not observed. In contrast, both phytochromobilin and phycocyanobilin interact with phyB apoprotein and induce phyB specific photosensory functions. Structural requirements of the apoproteins and the chromophores for the specific photoperception of phyA and phyB are discussed.

• 한국주조공학회지
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• 제12권2호
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• pp.131-138
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• 1992

The effects of B additions, alone or in combination with Si, on the microstructure, $DO_3{\rightleftharpoons}B2$ transition temperature($T_c$) and corrosion behavior of Fe-25at%Al alloys were investigated. The raw materials were arc-melted in vacuum and then subjected to the following heat treatments to maximize the $DO_3$ order : homogenized at $1000^{\circ}C$ for 48hrs, slowly cooled to $500^{\circ}C$, and held at that temperature for 24hours. Results showed that the B addition to Fe-25at%Al alloys does indeed refine the grain and change from intergranular to transgranular fracture mode at room temperature, indicating a strengthening of grain boundaries. The Fe-25at% Al-1at% B-3at% Si alloy showed the highest $T_c$(${\Delta}T_c=150^{\circ}C$) in this work. However, the effectiveness of Si in raising $T_c$ decreased with more than 5at% Si additions combined with B. Since the preferential corrosion occurs at the precipitates, the corrosion resistance decreased due to the increased amount of precipitates with alloying additions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.367-368
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• 2007

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.181-184
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• 2004

This study proposes two utilization ways of Saaty's compatibility metric to an entire hierarchy: (a) composite mode of all priorities and compatibility indices pertaining to a hierarchy, (b) arithmetic mean of compatibility indices along the hierarchy levels using a reduced elementwise operation of two eigenvectors.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1997년도 동계 학술대회 논문집
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• pp.227-232
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• 1997

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.833-834
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• 2008