• 한국분말재료학회지
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• 제19권2호
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• pp.134-139
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• 2012

P/M coppers are subjected to the isothermal compression tests at the strain rate ranging from 0.01 to 10.0 $s^{-1}$ and the temperature from 200 to $800^{\circ}C$. The processing map reveals the dynamic recrystallization (DRX) domain in the following temperature and strain rate ranges: $600-800^{\circ}C$ and 0.01-10.0 $s^{-1}$, respectively. In the domain, the region at temperature of $600^{\circ}C$ and strain rate of $10^{-2}s^{-1}$ shows peak efficiency. From the kinetic analysis, the apparent activation energy in the DRX domain is 190.67 kJ/mol and it suggests that lattice self-diffusion is the rate controlling mechanism.

• 대한의용생체공학회:의공학회지
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• 제8권2호
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• pp.123-134
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• 1987

The transport phenomena of alkali metal chlorides through poly(2 hydroxyethyl methacrylate) hydrogel membrane have been studied using electrodialysis. The hydrogel membranes were prepared by the polymerization of 2-hydroxvethyl methacrylate in the presence of 45%(V/V) H2O and ethyleneglycodimethacrylate. The initiator used in the polymerization was azobismethylisobutyrate (AMIB) prepared from azobisiobtyronitrile (AIBN) using Mortimer method. The permeability of alkali metal chlorides such LiCl, NaCl and KCI at 50 voltage was obtained. The permeability of NaCl was also observed at 30, 40, 50, and 60 voltages respectively. The concentration of solutes permeated through the membrane was measurer by flame photometry. The experimental results have been discussed with the comparison of apparent solute molecular size, the self-diffusion coefficient of solutes, the transport number of cations in aqueous solution. These indic aloes that poly(2 hydroxyethyl methacrylate) hydrogel membrane shows a specific selectivity for sodium ion.

• 복식문화연구
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• 제16권4호
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• pp.634-645
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• 2008

The purpose of this study was to develop cruise look design inspired by the ocean life motif using by computer CAD system. Domestic and international brands were selected for this study researching cruise line collection. A variety of literature and online site for concept of cruise look and sustainable design was studied. Adobe Illustrator CS2 and Adobe Photoshop CS2 program were used for cruise look design through analysis of 07/08 S/S trend. The diffusion of cruise look reflects a societal trend to be changed life pattern. The results of this study are as below. First, as this society has become modernized with advancement of technology, people have been increasingly interested in the pursuit of happiness and the concept of 'quality of life', thereby creating a new trend of consumption culture. As a result, fashion market place changed targeting sensible and self-enrichment customers. Second, as combining rapid technological innovation and mass production, industrial design caused environmental pollution and the problems are being worsen. Fashion design has same problems and led to eco-friendly design by the large. Third, as the change of style influenced by economic and social condition, cruise look re-defined and became more common. The change of various fields led to fashion market place should be changed. The cruise look design using computer program will give more benefits to many designers.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.187-192
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• 2008

A simplified model for an isolated aluminum particle burning in air is presented. Burning process consists of two stages, ignition and quasi-steady combustion (QSC). In ignition stage, aluminum which is inside of oxide film melts owing to the self heating called heterogeneous surface reaction (HSR) as well as the convective and radiative heat transfer from ambient air until the particle temperature reaches melting point of oxide film. In combustion stage, gas phase reaction occurs, and quasi-steady diffusion flame is assumed. For simplicity, 1-dimesional spherical symmetric condition and flame sheet assumption are also used. Extended conserved scalar formulations and modified Shvab-Zeldovich functions are used that account for the deposition of metal oxide on the surface of the molten aluminum. Using developed model, time variation of particle temperature, masses of molten aluminum and deposited oxide are predicted. Burning rate, flame radius and temperature are also calculated, and compared with some experimental data.

• 소음진동
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• 제10권4호
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• pp.610-614
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• 2000

Cellular Automata(CA)s are used as a simple mathematical model to investigate self-organization in statistical mechanics, which are originally introduced by von Neumann and S. Ulam at the end of the 1940s. CAs provide a framework for a large class of discrete models with homogeneous interactions, which are characterized by the following fundamental properties: 1) CAs are dynamical systems in which space and time are discrete. 2) The systems consist of a regular grid of cells. 3) Each cell is characterized by a state taken from a finite set of states and updated synchronously in discrete time steps according to a local, identical interaction rule. 4) The state of a cell is determined by the previous states of a surrounding neighborhood of cells. A cellular automaton has been attracted wide interest in modeling physical phenomena, which are described generally, partial differential equations such as diffusion and wave propagation. This paper describes one and two-dimensional analysis of wave propagation phenomena modeled by CA, where the local interaction rules were derived referring to the Lattice Gas Model reported by Chen et al., and also including finite difference scheme. Modeling processes by using CA are discussed and the simulation results of wave propagation with one wave source are compared with that by finite difference method.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.118-118
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• 1999

CVD방법에 의한 TiN 박막 형성에 있어서 ICP-CVD 방법이 대두되고 있다. 이것은 precursor에 대한 radical 형성, 식각된 패턴에서 양 벽의 self-shadowing 효과, 낮은 tress등으로 dense 한 박막을 얻을 수 있기 때문이다. TiN 박막은 Si 기판의 온도를 상온에서 50$0^{\circ}C$까지 유지하면서 TEMAT의 유량을 5-20sccm으로 변화시키면서 증착하였다. 증착 후 TiN 박막의 결정화에 따른 열처리는 Ar과 N2-가스분위기에서 in-situ로 증착하였다. 증착 후 TiN 박막증착 조건수립에 따른 플라즈마 특성진단은 전자의 온도와 밀도, 평균 전자밀도, 이온 에너지 분포, radical 분포, negative 이온분포 등으로 측정하였다. 플라즈마 변수에 따른 TiN 박막의 결정성과 상 변화는 XRD로 분석하였고, 조성비 및 TiN 박막의 원소화학적 상태, 결합에너지, 각 상에 따른 결합 에너지 천이정도, 초기 형성과정 및 반응기구 등은 RBS와 XPS로 조사하였다. TiN 박막의 표면상태, morphology 거칠기, TiN/Si(100)구조에서 계면상태 등은 SEM, AFM, 그리고 HRTEM으로 분석하였다. TiN 구조 박막의 비저항, carrier concentration 그리고 mobility 측정은 박막의 표면이 균일하고 bls-홀이 없는 것으로 하여 4-point probe 방법으로 측정하였다. 이들 분석으로부터 ICP-CVD 방법에 의하여 형성된 TiN 박막이 초고집적 반도체 소자의 contact barrier layer로서의 적용 가능성을 평가하였다.

• 한국인터넷방송통신학회논문지
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• 제16권1호
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• pp.183-191
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• 2016

스마트폰의 확산과 더불어 SNS는 눈부시게 성장하고 있다. 그러나 SNS의 사용이 과해짐에 따라 SNS 중독이라는 사회문제가 대두되고 있다. 한편 SNS에 대한 부정적인 인식 때문에 사용자가 SNS를 떠나는 것 역시 문제로 떠올랐다. 이와 같이 SNS의 중독 및 지속사용 모두 SNS의 사용에 있어 중요한 문제이며, 이에 본 연구에서는 기본심리욕구를 원인 변인으로 선정하여 그 영향력을 확인하고자 하였다. Facebook 사용자 204명을 대상으로 한 연구결과 자율성 및 유능성은 Facebook 중독에 유의한 영향을 미쳤으며, 자율성, 유능성 및 관계성은 Facebook 지속사용의도에 유의한 영향을 미치는 것으로 나타났다.

• 한국안전학회지
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• 제1권1호
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• pp.41-49
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• 1986

Modern technological progress demands the use of materials at high temperature and high pressure. One of the most critical factors in considering such applications-perhaps the most critical one-is creep behavior. In this study the activation energy for the creep rupture (Qf) and the stress dependence of rupture time (n') have been determined during creep of Al 7075 alloy eve, the temporature range of $200^{\circ}C to 500^{\circ}C$ and stress range of 0.64 kgf/$\textrm{mm}^2$ to 9.55 kgf/$\textrm{mm}^2$, respectively, in order to investigate the creep-rupture property. Constant load creep tests were carried out in the enperiment At around the temperature $210^{\circ}C~390^{\circ}C$ and the stress level 1.53~9.55(kgf/$\textrm{mm}^2$), the stress dependence of rupture time(n') had the value of 6.6~6.78 but at 50$0^{\circ}C$, the value of 1.3. Besides at around the temperature of $200^{\circ}C~500^{\circ}C$ and under the stress level of 0.89~8.51 (kgf/$\textrm{mm}^2$), the activation energy for the creepprupture (Qf) was nearly equal to that of the volume self diffusion of pure aluminum (34Kca1/mo1e)

• Asian Journal for Public Opinion Research
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• 제1권4호
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• pp.268-291
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• 2014

Social media is becoming more and more important in social movements. This study, adopting the web mining approach, attempts to investigate how social media, Facebook in particular, functioned in the "May 25 Protest" and the "May 27 Protest", two movements which broke out in Macao on 25 and 27 May 2014, respectively, against the Retirement Package Bill. In the two protests, Macao residents deployed Facebook to share information and motivated people's participation. Twelve events (181,106 people invited) and 36 groups/pages (41,266 members) related on Facebook were examined. Results showed that the information flow on Facebook fluctuated in accordance with the event development in reality. Multiple patterns of manifestation, such as video of adopted news or songs, designed profile (protest icon), original ironic pictures, self-organized clubs by undergraduates and white T-shirts as a symbol, among others, appeared online and interacted with offline actions. It was also found that social media assisted the information diffusion and provided persuasive reasons for netizens to join the movement. Social media helped to expand movement influence in providing a platform for diversified performances for actions taken in a protest, which could express and develop core and consistent movement repertoire.

• 지식경영연구
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• 제16권1호
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• pp.117-142
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• 2015

Recently, the personal cloud computing service has been being spotlighted as an individual tool of productivity enhancement. However, compared to the rosy forecast, its diffusion rate in the domestic (Korean) market is much slower than expected. In order to find the reason for the slow growth of personal cloud computing service, we attempt to identify influencing factors on user's adoption resistance, while most prior research has focused on the factors affecting its adoption. Based on both the person-technology fit model and the privacy calculus model, we propose technostress and perceived value as key antecedents of adoption resistance. In addition, we identify (1) technical (pace of change and complexity) and personal (self-efficacy) influencing factors on technostress, and (2) beneficial (perceived mobility and perceived availability) and harmful (perceived vulnerability) influencing factors on perceived value. To validate our research model, 133 individual samples were gathered from undergraduate and graduate students who had actual experience of using at least one of personal cloud computing services. The results of the structural equation modeling confirm that both technostress and perceived value have significant effects on adoption resistance, but they have different influencing mechanisms to different types of adoption resistance (indifference, postponement, and rejection). Theoretical and practical contributions are discussed in the conclusion.