• 한국자동차공학회논문집
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• 제13권6호
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• pp.187-194
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• 2005

The objective of this study is to validate the hybrid breakup model and the vaporization model for GDI spray analysis at vaporization and non-vaporization conditions. The atomization process is modeled by using hybrid breakup model that is composed of Linearized Instability Sheet Atomization (LISA) model and Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model. The vaporization process is modeled by using modified Abramzon & Sirignano model. The exciplex fluorescence method was used for comparing the calculated results with the experimental ones. The experiment and the calculation were performed at the ambient pressures of 0.1 MPa, 0.5 MPa and 1.0 MPa and the ambient temperature of 293K and 473K.

• 대한전기학회논문지
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• 제38권2호
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• pp.127-136
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• 1989

This paper describes the parameter convergence properties of an adaptive system to identify a single-input single-output plant model. It is demonstrated that, by using power spectrum analysis, the persistency of excitation (PE) condition in order to guarantee the exponential stability of the adaptive control system can be transformed into the positive definite behavior for the auto-correlation function matrix of adaptive signal. The existence of parameter nominal values can be analyzed by this condition and the convergence rates of parameter are determined by examining the auto-correlation function. We may use the sufficient richness (SR) of input spectrum instead of the PE condition to analyze the parameter boundedness. It can be shown that the eigen values of the auto-correlation function are always related with adaptive gain, input amplitude and positions or numbers of input spectra. In each case, the variation of parameter convergence rate can be also verified.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2010년도 제3회 국제학회
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• pp.205-206
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• 2010

This Study executed the newly developed warp knitted fabrics for the end of living textile materials and investigated the dyeing behavior with the change of drying temperature. There were also analysis of yarn properties in the process of dyeing and finishing. Above all, we examined the influence of touch and softness according to processes. So we can expect the optimum yarn and condition for the better textile goods.

• 한국초전도ㆍ저온공학회논문지
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• 제11권3호
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• pp.60-64
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• 2009

We investigated an operating characteristic of linear-type magnetic flux pump (LTMFP) as a current compensator under the various conditions. In order to explain the mechanism of the LTMFP, the magnetic behavior of superconducting Nb foil according to pumping actions should be understood. In this paper, the magnetic field analysis of superconducting Nb foil installed in LTMFP has been performed based on the three-dimensional finite element method (3D FEM). Through the simulation analysis, the normal spot region on the superconducting Nb foil is found to be enhanced swiftly over about 20 Hz. The simulated finding agreed with an analytical estimation based on the phenomenon of magnetic diffusion.

• 한국초전도ㆍ저온공학회논문지
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• 제12권1호
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• pp.47-51
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• 2010

We already obtained magnetic behavior of superconducting Nb foil of linear type magnetic flux pump (LTMFP) by means of the FEM analysis. As well as, fundamental equations of pumping current were theoretically derived based on the pumping sequences according to the position of normal spot of the moving flux. In this paper, we experimentally investigated pumping performances of LTMFP with a wide range of traveling speed of magnetic field. In order to confirm the numerical and theoretical approaches, we explained the pumping characteristics of LTMFP by use of the calculation sequence of pumping current.

• 인간식물환경학회지
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• 제22권5호
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• pp.515-524
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• 2019

This study was conducted based on the fact that children in institutions for early childhood education located in cities lack the opportunity to experience nature. Therefore, urban parks are where it is possible to observe nature and natural environment, through which we examined the effects of nature activities on kindergarten children's curiosity and scientific problem-solving ability. The subjects of this study were 5-years old kindergarten children in attending public kindergartens in Cheonan and Asan and 42 children were randomly selected. The pretest and posttest were conducted on curiosity and scientific problem-solving ability before and after nature activities. The results showed that nature activities in urban parks had significant effects on improvement of kindergarten children's curiosity and scientific problem-solving ability (p <.05). Therefore, nature activities in urban parks had positive effects on preference for unknown and exploratory behavior, which are sub-factors of kindergarten children's curiosity. Nature activities also had positive effects on discovery and statement of the problem, creation and application of ideas, and conclusion to problem solving.

• 농업과학연구
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• 제18권1호
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• pp.41-48
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• 1991

각(各) 조건별(條件別) 감자전분(澱粉) 호화액(湖化液)을 Brookfield 단원통(單圓筒) 회전점도계(回轉粘度計)로 실험(實驗)한 리올로지 특성(特性)을 살펴보면, 3-7%의 감자전분(澱粉) 호화액(湖化液)은 모두 강복응력(降伏應力)을 갖는 의가소성(擬可塑性) 유체(流體)로서 시간의존성(時間依存性) 구조붕괴(構造崩壞)를 나타내는 Thixotrophic 특성(特性)을 나타내었다. 여기서 점조도지수(粘租度指數)와 강복응력(降伏應力)은 농도(濃度)에 비례(比例)하였으나, 유동거동지수(流動擧動指數)는 각(各) 조건(條件)에서 일정(一定)한 관계(關係)를 보이지 않았다. 첨가제(添加製)인 인산염(燐酸鹽)을 첨가(添加)하였을 때 호화(湖化) 감자전분(澱粉)의 점조도지수(粘租度指數)와 강복응력(降伏應力)값은 크게 감소(減少)하였으나 유동거동지수(流動擧動指數)의 값은 약간 증가(增加) 하였다. 또한 4% 감자 전분(澱粉) 호화액(湖化液)에서 초기(初期) 및 평충상태(平衝狀態) 에서 활성화(活性化) 에너지를 측정(測定)한 값은 각각 1.52Kcal/g.mole과 1.27 Kcal/g.mole 이었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.100-105
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• 2003

25Cr-20Ni series strainless steel have an excellent high temperature strength, high oxidation and high corrosion resistance. However, further improvement can be creep strength by work hardening prior creep. In the present study, the effect of prestraining at room temperature on the creep behavior of a Class M(STS310S) and a Class A(STS310J1TB) alloy containing precipitates have been examined. Prestraining was carried out at room temperature and range of prestrain was $0.5{\sim}2.5$ % at STS310J1TB and $2.0{\sim}7.0$ % at STS310S. Creep behavior and creep rate of pre-strained specimens were compared with that of virgin specimens. Room temperature prestraining produced the creep life that is longer than that of a virgin specimen both for STS310J1TB and STS310S when creep test carried out at the temperature lower than recrystallization temperature. The reason for this improvement of creep life was ascribable to the interaction between dislocations and precipitates in addition to the dislocation-dislocation interaction in STS310J1TB and the dislocation-dislocation interaction in STS310S. The beneficial effect of prestraining in STS310J1TB was larger than that of STS310S.

• 한국결정성장학회지
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• 제7권1호
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• pp.143-150
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• 1997

본 연구는 수소로 희석된 $B_2H_6$를 도판트 소스 가스로 사용하여 이온 질량 주입(ion mass doping)을 하였을 때 다결정 박막의 전기적 특성과 도판트의 활성화시 방사 손상(radiation damage)의 효과에 대하여 고찰하였다. 다결정 박막에서 보론(boron)의 SIMS 분석과 컴퓨터 시뮬레이션인 TRIM92를 비교해서 가장 주입 확률이 높은 이온의 종류는 $B_2H_x\;^+$(x=1, 2, 3‥‥) 형태의 분자 이온임을 알았다. 높은 에너지의 질량 이온 주입 결과 시간에 따라 변화하는 비정질화된 층의 분율이 다결정 박막 내에 연속적인 비정질 충으로 존재하였다. 주입 이온의 질량 분리가 일어나지 않는 이온 질량 주입법(ion mass doping technique)에 의해 비정질화는 유발된다. 손상된 시편의 중간 열처리 온도 범위에서 도판트 활성화 거동과 역 열처리(reverse annealing) 효과가 관찰되었다. 이와 같은 연구의 결과 p-채널 다결정 박막 트랜지스터의 오프 스테이트(off-state) 전류는 방사 손상(radiation damage)에 의존한다.

• 한국패션뷰티학회지
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• 제5권1호
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• pp.56-70
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• 2007

Shade cosmetics that were considered to be women's exclusive possession, are now expanding its market to men and teenagers. As a result, development of subdivided shade cosmetics is becoming active. In these market environments consumers demand various personalized desires through beauty care, therefore enterprises have to establish marketing strategies to meet these desires. Accordingly this study aimed to provide information actually needed in cosmetics development by researching shade cosmetics in subdivision according to items and basic data that will be helpful in establishing marketing strategies of shade cosmetics. The survey was conducted among adult females with age of 20 to 26, living in Seoul and several local cities. 387 survey papers were used in the analysis among 500 survey papers distributed. The results were summarized as following. First of all, many women were doing overall makeup generally. The younger they tended to do partial makeup more and the older they tended to do overall makeup more according to the analysis on actual conditions of using shade cosmetics. Many women got information related to shade cosmetics from friends or family. This is an example of the fact that shows collecting information from human relationship such as friends and family played an important role and surrounding environment can be a factor that can have impact on purchasing behavior. Purpose of makeup was mostly to show courtesy and the younger they tend to answer that they do makeup to look beautiful. The order of the most frequently used shade makeup was makeup base>foundation>two way cake. The most important focusing point in shade makeup was the eye. In choosing colors they chose their favorites colors most frequently.