• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.96-96
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• 2003

비정질 합금은 기존 결정질 합금에서는 얻을 수 없는 독특한 물리적, 화학적, 기계적, 전자기적 특성을 나타내는 것으로 알려져 있다. 비정질을 형성하기 위해서는 매우 큰 냉각속도가 필요하므로 제조 가능한 비정질 합금은 분말, ribbon, 박판 형태로 제한되어 있다. 최근 비정질 분말 제조 및 벌크 비정 질에 관한 연구는 많은 발전을 보아 왔지만, 아직도 고청정 비정질 합금 분말의 제조와 대량 생산화 관해서는 많은 연구가 요구된다. 본 연구에서는 고청정 Ni-Zr-Ti-Si-(Sn)계 벌크 비정질 분말을 가스분무법으로 제조하였다. 제조된 합금 분말은 각 입도 별로 구분하여, XRD 분석을 통하여 비정질 형성 가능 입도을 분석하였다. 분말의 외형은 SEM으로 분석하였으며, 미세구조는 TEM을 사용하였다. 열적특성은 DSC 분석으로 조사하였다. 또한 제조한 비정질 분말의 미세구조와 비교하기 위하여 Tg와 Tx 온도범위에서 열처리 한 분말의 미세구조를 분석하였다. XRD 분석 결과, 가스분무법으로 제조된 Ni-Zr-Ti-Si-(Sn) 분말 중에서 75$\mu\textrm{m}$ 이하의 분말은 비정질상을 가졌으며, 75$\mu\textrm{m}$ 이상의 분말은 결정질 또는 비정질의 혼합 상으로 구성되었다. 비정질 분말 회수율은 약 60% 이상이었다. 미세 TEM 분석에서 75$\mu\textrm{m}$ 이하 분말은 전형적인 비정질 Halo 형상을 보였으며, 결정질이 혼합된 분말은 비정질 기지상에 결정질 응고 수지상 조직이 혼합되어 있음을 확인하였다.

• KOMUNHWA
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• no.63
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• pp.5-42
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• 2004

Several new results were come from the third excavation of the Isimila site in Tanzania which is well known for typical Acheulean industry from the late Middle Pleistocene deposits. The research was carried out in 2003 by the Institute of Cultural Propert

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.373-382
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• 1999

Inheritance and concurrency are the primary feature of object oriented languages, and are especially important for code re-use. They provide maximum computational power and modeling power through concurrency of objects. But, concurrent objects and inheritance have conflicting characteristics, thereby simultaneously use of them causes the problem, so called inheritance anomaly, which requires code redefinition of inherited methods to maintain integrity of objects. In this paper, to solve the inheritance anomaly problems we introduce concept of state abstraction, in which internal states of encapsulated objects are made available from a part of object's external interface. And we design inheritance interface mechanisms which methods are inherited efficiently. In our scheme, we can solve the typical inheritance anomaly problems.

• Journal of Korean Library and Information Science Society
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• v.41 no.1
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• pp.5-28
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• 2010

The purpose of this study is to investigate the major features of Next Generation Library Catalogs. 'Next Generation Melvyl Pilot' of University of California Library System and 'SearchWorks' of Stanford University Library are examined. While the former is developed, based on OCLC WorldCat Local, the latter is based on the Blacklight, an Open Source Catalog Software. Both commonly provide the features, including enriched contents, facet navigation, keyword searching, relevancy ranking of search results, and user contribution, etc., but some functions vary in scopes and contents. Also, it seems that both are in process of development rather than complete implementations.

• Applied Biological Chemistry
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• v.29 no.4
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• pp.333-338
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• 1986

Physicochemical properties of starch isolated from germinated corn were investigated and compared with those of nongerminated corn starch. Amylose content and initial gelatinization temperature of germinated starch were lower than those of nongerminated starch. Swelling power and solubility of both starches exhibited two stage behavior, however germinated starch revealed lower swelling power and higher solubility compared to those of nongerminated starch. Both starches showed a typical A type X-ray diffraction and irregular oval shape including partly polygon with the size of $10-25{\mu}m$. However, germinated starch showed many holes with the size of $1-2{\mu}m$ on the surface of granule.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.8
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• pp.36-41
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• 2013

This paper is development of single-phase brushless DC motor with outer rotor for ventilation fan. Cogging torque causes the noise vibration to greatest impact on ventilation fan. Asymmetric notches are applied to tapered-teeth for cogging torque reduction of single-phase brushless DC motor. Initial model is notchless and proposed model is applied 2 asymmetric notches. The proposed method is proved motor characteristic through finite element analysis(FEA). Also, experimental results verify that the proposed model considerably reduces cogging torque and have the good sound quality in ventilation system.

• Membrane Journal
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• v.1 no.1
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• pp.44-54
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• 1991

Sulfonated polystyrene-divinylbenzene(PS-DVB) copolymer membranes were prepared using different diluents (toluene, cyclohexane, cyclohexanol), various diluent ratio and DVB contents. And initial fluxes of organic acids were investigated by varying pH and initial concentration. As a results, water content and ion-exchange capacity decreased with increasing DVB concetration. Among used diluents, cyclohexanol was the most efficient for building up the highest water content and ion-exchange capacity. In the experiment of permeation, carboxylic acid such as formic acid and acetic acid showed higher fluxes when pH was lower than pKa and amino add such as L-alanine showed minimum flux when pH was isoelectric value. The relationaship between initial fluxes and initial concentrations has been expressed by saturation kinetics.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.173-178
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• 2001

The effects of heat-treatment with magnetic or non-magnetic field on magnetic properties of gas-atomized MPP dust cores subjected to various cooling processes after annealing were investigated. Upon magnetic-field annealing, ac permeability and core loss decreased with the increase of cooling rate, which were attributed to the generation of inhomogeneous internal stress and anomalous eddy current loss, respectively. It was not observed the formation of ordered phase and the related change in magnetic properties at the cooling stage for MPP dust cores. In MPP alloys, magnetic anisotropy was easily induced through the directional order, and permeability and core loss were changed under the conditions of low cooling rate and magnetic annealing.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.226-232
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• 2007

모바일폰의 LCD 전면화 추세로 인해 터치스크린을 기반으로 하는 모바일폰이 컨셉폰의 형태로 선보여지고 있고, 부분적으로 터치스크린을 차용한 모바일폰이 국내, 국외에 출시되고 있다. 터치스크린은 간편하고 직관적인 조작감을 제공하며 유동적인 인터페이스를 가능하게 하는 장점이 있다. 그리고 이러한 터치스크린의 장점을 적극적으로 활용할 수 있도록 하는 진보된 인터랙션 스타일도 다양하게 제안되고 있다. 하지만 기존의 터치스크린 기반의 모바일폰은 스타일러스를 그대로 사용하듯, 제한적이고 전형적인 인터렉션만을 제공하고 있고, 제안된 진보된 인터렉션 스타일들도 터치스크린 기반의 모바일폰에 직접적으로 활용하기는 어려운 실정이다. 본 연구는 진보된 인터랙션 스타일 중에서, 원 포인팅과 2개 이상의 포인팅이 가능한 멀티 포인팅 인터랙션을 연구하여 터치스크린기반의 Full LCD 모바일폰에 적합한 인터랙션 스타일을 제안한다. 이를 위해, 인터랙션에 대한 문헌연구와 함께 터치스크린을 기반으로 하는 다양한 디지털기기를 검토해보고, 터치스크린에 적용 가능한 진보된 인터랙션 사례들을 조사하였다. 그 후 터치디스크린 기반의 디지털기기를 사용하는 사용자의 행태를 파악하기 위한 유저테스트 및 인터뷰를 실시하여, 터치스크린 기반의 모바일폰에서 구현되어야 할 상세 인터랙션 스타일을 도출하였다. 본 연구에서 제안된 인터랙션 스타일은 다양한 사용자 경험을 가능하게 하여 고기능, 고사양화 되어가는 모바일폰의 UI를 보다 효과적으로 사용하는데 도움을 줄 것으로 기대된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4C
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• pp.418-424
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• 2007

This paper proposes a scheme to track channel response in OFDM systems with null sub-carriers. The proposed channel tracking scheme estimates the channel response first in the frequency domain by using the decision directed data. The time domain channel estimation is then performed to remove additive white Gaussian noise (AWGN) components further. Due to the channel estimation in the frequency domain, no inverse matrix calculation is required in the time domain channel estimation. Computational reduction in the proposed method is about 93%, compared with the conventional time domain channel estimation method. Mean square error (MSE) and bit error rate (BER) performances are evaluated by using computer simulation. The proposed method shows the same performance as that of the conventional time domain channel estimation even though the significant computational reduction.