• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.128-128
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• 2013

Fabrication of heterogeneous catalysts using Atomic Layer Deposition (ALD) has recently been attracting attention of surface chemists and physicists. In this talk, I will present recent results about structures and chemical activities of various catalysts prepared by ALD, particularly focusing on Ni-based catalysts. Ni has been considered as potential catalysts for $CO_2$ reforming of methane (CRM); however, Ni often undergoes rapid decrease in catalytic activity with time, and therefore, application of Ni as catalysts for CRM has been regarded as difficult so far. Deactivation of Ni catalysts during CRM reaction is from either coke formation on Ni surface or sintering of Ni particles during reaction. Two different strategies have been used for enhancing stability of Ni-based catalysts; $TiO_2$ nanoparticles were deposited on micrometer-size Ni particles by ALD, which turned out to reduce coke formation on Ni surfaces. Ni nanoparticles deposited by ALD on mesoporous silica showed high activity and long-term stability from CRM without coke deposition and sintering during CRM reaction. Ni-based catalysts have been also used for oxidation of toluene, which is one of the most notorious gases responsible for sick-building syndrome. It was shown that onset-temperature of Ni catalysts for toluene oxidation is as low as $120^{\circ}C$. At $250\circ}C$, total oxidation of toluene to $CO_2$ with a 100% conversion was found.

• Journal of the Korean Wood Science and Technology
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• 제34권4호
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• pp.9-14
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• 2006

PEG처리재의 치수안정성 기구를 조사하기 위해 에너지분산스펙트럼분석법(SEM-EDS)을 이용하여 세포벽 내에 존재하는 PEG분자들의 분포를 분석하였다. 주사전자현미경으로 관찰한 결과, 무처리재의 세포들은 건조에 의한 수축이 발생하여 세포들이 찌그러진 형태를 나타냈지만, PEG처리재의 세포는 세포벽이 무처리재에 비해 다소 팽윤되었고, 세포들은 거의 원형을 유지하고 있었다. SEM-EDS법으로 분석한 결과, 세포벽에 K이온이 고르게 분포되어 있는 것이 관찰되었다. 따라서 PEG분자는 세포벽 내까지 침투하여 목재의 치수안정성 증대에 기여하는 것이 확인되었다.

• 한국정보시스템학회지:정보시스템연구
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• 제20권3호
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• pp.81-109
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• 2011

The increase in the number of smartphone users has recently been steep, which started to offer companies and individuals more opportunities to enter into a new business field. Furthermore, the smartphone applications have become one of the hottest topics inside and outside the mobile industry. Still the market is in its infancy and intention to pay of charged application of most smartphone users is relatively low. However, rate of charged application in appstore is expected to be increase steadily for some years to come. In this perspective, it is important to consider the smartphone mobile application. Research on smartphone application is still in its early stage. Thus, the purpose of this study is to find what are the effective factors on user satisfaction and intention to pay of mobile application. Based on information system success model, we proposed system quality(stability, usability, security), information quality(timeliness, accuracy, enjoyment) and service quality(reactivity, reliability, empathy) as factors to effect on user satisfaction in mobile application. The results showed that stability, usability, timeliness, accuracy, enjoyment, reactivity and empathy affected significantly user satisfaction. The relationship among satisfaction and intention to pay of mobile application was significantly supported. The implications of the findings is that firms and individual developers of mobile application should focus on customer retention through enhancing satisfaction and quality.

• 전자공학회논문지A
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• 제31A권5호
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• pp.85-93
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• 1994

We have studied the effect of channel and/or spacing chirpings on the near field and near field intensity patterns, modal gains and radiation angles of 6 supermodes in the index-guided laser arrays with 6 channels, on the basis of the coupled mode theory. The spacings between channels can be indenpendent parameters for control of the radiation angle. It is found that an asymmetrically v channel-chirped array has both a smaller radiation angle and better supermode discrimination characteristics than a uniform array. Comparing two approaches for enhancing modal stability in point of supermode discrimination characteristics, approach I which increases the coupling cofficient between the outer-most waveguides at each end of an otherwise uniform array, has superior discrimination characteristics to the approach II which increases the propagation constant for the end elements with the same coupling between neighbor elements. Approach III which has a narrower spacing between the outer-most waveguides at one end and a wider channel width of the outer-most waveguide at another end, gets a narrower radiation angle than the approach I and good supermode discrimination characteristics by applying optimized gain profiles.

• International Journal of Aeronautical and Space Sciences
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• 제8권1호
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• pp.32-45
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• 2007

The T-50 advanced supersonic jet trainer employs the Relaxed Static Stability (RSS) concept to improve the aerodynamic performance while the flight control system stabilizes the unstable aircraft and provides adequate handling qualities. The T-50 flight control laws employ a proportional-plus-integral type controller based on a dynamic inversion method in longitudinal axis and a proportional type controller based on a blended roll system with simple roll rate feedback and beta-betadot feedback system. These control laws are verified by flight tests with various maneuver set flight envelopes and the control laws are updated to resolve flight test issues. This paper describes several concepts of flight control laws used in T-50 to resolve those flight test issues. Control laws for solving the roll-off problem during pitch maneuver in asymmetric loading configurations, improving the departure resistance in negative angle of attack conditions and enhancing the fine tracking performance in air-to-air tracking maneuvers are described with flight test data.

• 한국정밀공학회지
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• 제28권3호
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• pp.357-362
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• 2011

Air springs are prevalently used as suspension in train. However, air springs are seldom used in automobiles where they improve stability and comfort by enhancing the impact-relief, breaking, and cornering performance. Thus, this study proposed a new method to analyze air springs and obtained some reliable design parameter which can be utilized in vehicle suspension system in contrast to conventional method. Among air spring types of suspension, this study focused on sleeve type of air spring as an analysis model since it has potential for ameliorating the quality of automobiles, specifically in its stability and comfort improvement by decreasing the shock through rubber sleeve. As a methodology, this study used MARC, as a nonlinear finite element analysis program, in order to find out maximum stress and maximum strain depending on reinforcement cord's angle variation in sleeves. The properties were found through uniaxial tension and pure shear test, and they were developed using Ogden Foam which is an input program of MARC. As a result, the internal maximum stresses and deformation according to the changes of cord angle are obtained. Also, the results showed that the Young's modulus becomes smaller, then maximum stresses decrease. It is believed that these studies can be contributed in automobile suspension system.

• 한국터널지하공간학회 논문집
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• 제2권2호
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• pp.32-40
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• 2000

본 논문에서는 수평보강재로 보강된 터널 막장의 거동에 대한 매개변수 연구를 다루었다. 매개변수 연구에서는 축소모형실험을 수행하였으며 실험 결과를 이용하여 보강막장의 거동을 고찰하였다. 실험결과 터널 막장은 수평보강재로 보강함에 따라 변형이 억제되어 안정성이 증대되는 경향을 보였으며, 이러한 결과는 3차원 유한요소해석 결과와 정성적인 면에서 좋은 일치를 보였다. 따라서 막장 수평보강 공법은 막장의 안정성을 향상시키는 매우 유용한 공법으로 적용될 수 있을 것으로 판단되며, 일반적인 설계법을 개발하기 위해서 3차원 유한요소해석 모델링이 활용될 수 있을 것으로 사료된다.

• Elastomers and Composites
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• 제43권2호
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• pp.72-81
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• 2008

포장도로의 소성변형을 줄여보고자 개질아스팔트가 나타나고 있다. 본 연구에서는 타이어 고무 등을 이용하여 개질된 아스팔트의 물성을 알아 보았다. 마샬안정도와 인장강도가 각각 98% 및 43% 증가하여 타이어 고무의 개질효과를 알 수 있었다. 점도, 침입 및 열 분석에서 아스팔트의 변형저항성이 향상되었음을 알 수 있었다. IR 및 GPC 실험에서 개질제의 구조가 아스팔트의 구조와 유사할 경우 두 화합물 사이에 화학결합이 발생하여 분자들의 크기가 증가함으로써 개질효과가 커짐을 알 수 있었다.

• 멤브레인
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• 제24권6호
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• pp.448-452
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• 2014

올레핀/파라핀 분리 기술로 silver nanoparticles(AgNPs)를 운반체로 사용하여 보다 효과적으로 올레핀을 분리하는 고성능 올레핀 촉진수송 분리막을 제조하고자 하였다. 기존에 성능이 밝혀진 PVP/AgNPs/TCNQ 나노복합체 막에 추가적으로 할로겐 물질을 첨가하여 AgNPs의 표면을 더 양극화시킴으로써 성능을 향상시키고자 하였다. 제조한 용액을 TEM과 EDS로 분석해서 AgNPs의 형성과 iodine의 존재를 확인하였다. Propylene/propane 혼합기체의 분리 성능 실험을 통해 기존 PVP/AgNPs/TCNQ 나노복합체 분리막과 기체 분리 성능을 비교하였고, long-term stability 실험을 통해 분리막의 안정성을 조사하였다.

• 대한가정학회지
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• 제36권3호
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• pp.207-224
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• 1998

This study is approach to the Home-Based Work. More specifically, to examine about the families who try to combined home life and income-generation work under the same roof. Families were looking at Home-Based Work as one solution to the work-family crunch. Many research papers have suggested that Home-Based Work provides an effective way to balance the demands of paid employment and family responsibilities. Therefore, this proposed research reviewed the Home-Based Work as they contributed to individual and family satisfactions. The Prupose of this paper is to address issues related to Home-Based Work from the perspective of theory and application in family resource management, also to suggest a conceptual model for family work activities is advanced. This paper is examined concepts related to Home-Based Work employment that could be used to frame and describe the empirical study are specified. This paper was informed by analyses of data from project NE-167. "At-Home Income Generation: Impact on Management, Productivity, and Stability in Rural/Urban Families". The results from this paper will be helpful in enhancing the stability and satisfaction of families who worked in Home-Based Work.ased Work.