• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.51-67
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• 1999

The growth of crystals with high melting points tfus$\geq$1$600^{\circ}C$ faces the researcher with experimental problems, as the choice of materials that withstand such high t is rather limited. Many metallic construction materials are in this high t range already molten or exhibit at least a drastically reduced mechanical strength. The very few materials with tfus》1$600^{\circ}C$ as e.g. W, Mo, and partially even Ir are more or less sensitive against oxygen upon heating. Whenever possible, high t crystal growth is performed under inert atmosphere (noble gases). Unfortunately, any oxides are not thermodynamically stable under such conditions, as reduction takes place within such atmosphere. A thoroughly search for suitable growth conditions has to be performed, that are on the one side "oxidative enough" to keep the oxides stable and on the other side "reductive enough" to avoid destruction of constructive parts of the crystal growth assembly. The relevant parameters are t and the oxygen partial pressure pO2. The paper discusses quantitatively relevant properties of interesting oxides and construction materials and ways to forecast their behavior under growth conditions.r growth conditions.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.143-146
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• 2004

With the rapid growth of e-commerce, marketers are able to observe not only purchasing behavior on what and when customers purchased, but also the individual Web usage behavior that affect purchasing. The richness of this information has the potential to provide marketers with an in-depth understanding of customer. Using commonly available Web log data, this paper examines Web usage behaviors at the individual level. By decomposing the buying process into a pattern of visits and purchase conversion at each visit, we can better understand the relationship between Web usage behavior and purchase decision. This allows us to more accurately forecast a shopper's future purchase decision at the site and hence determine the value of individual customers to the siteAccording to our research, not only information seeking behavior but also visiting duration of a customer and participative behavior such as participation in event should be considered as important predicators of purchase decision of customer in a cosmetic internet shopping mall.

• Journal of the Korean Mathematical Society
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• v.33 no.2
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• pp.455-468
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• 1996

Certain analytic behavior of geometric objects defined on a Riemannian manifold depends on some very crude properties of the manifold. Some of those crude invariants are the volume growth rate, isoperimetric constants, and the likes. However, these crude invariants sometimes exercise surprising control over the analytic behavior.

• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.302-314
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• 2011

In today's fast changing management environment, new role of leaders is being emphasized for survival of companies, and organizational achievement must be maximized by using servant leadership strategically. Data were collected from the sample of 435 employee employed service. All analysis were conducted using LISREL 8.30. The research studies how servant leadership influences organizational citizenship behavior through psychological empowerment. The result is as follows. First, it is found that, among the servant leadership's behavior characters, except for empathy and ethics, growth, vision and community building are found to be variables that increase psychological empowerment. Secondly, it is fund that psychological empowerment of organization's members has positive correlation on organizational citizenship behavior. Thirdly, it is found that among the servant leadership's behavior characters, except for empathy and ethics, growth, vision and community building are found to have meaningful positive influence over organized citizens' behavior through psychological empowerment. Likewise, the result means the servant leadership increases organizational citizenship behavior of the members through empowerment. For servant leadership to promote organizational citizenship behavior, it is suggested to emphasize empowerment. In other words, it is important to empower subordinates for servant leadership to make more useful and complete achievement in the organization.

• Journal of Powder Materials
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• v.25 no.2
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• pp.104-108
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• 2018

Grain-growth behavior in the $95Na_{1/2}Bi_{1/2}TiO_3-5BaTiO_3$ (mole fraction, NBT-5BT) system has been investigated with the addition of $Na_2CO_3$. When $Na_2CO_3$ is added to NBT-5BT, the growth rate is higher than desired and grains are already impinging each other during the initial stage of sintering. The grain size decreases as the sintering temperature increases. With the addition of $Na_2CO_3$, a liquid phase infiltrates the interfaces between grains during sintering. The interface structure can be changed to be more faceted and the interface migration rate can increase due to fast material transport through the liquid phase. As the sintering temperature increases, the impingement of abnormal grains increases because the number of abnormal grains increases. Therefore, the average grain size of abnormal grains can be decreased as the temperature increases. The phenomenon can provide evidence that grain coarsening in NBT-5BT with addition of $Na_2CO_3$ is governed by the growth of facet planes, which would occur via mixed control.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.885-886
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• 2012

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.106-110
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• 1998

본 논문에서는 먼저 다층흡착에서 각 흡착층의 결합에너지가 서로 다른 경우의 흡착 등온선을 유도한다. 그리고 유도된 흡착등온식이 저압영역에서 헨리의 실험법칙을 잘 만족시킴을 보인다.

• Proceedings of the Korean Vacuum Society Conference
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• 2002.02a
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• pp.115-115
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• 2002

• Transactions of Materials Processing
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• v.21 no.3
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• pp.151-159
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• 2012

Finite element simulations were conducted to investigate the influence of grain growth in the superplastic blow forming process. A microstructure-based constitutive model considering grain growth effects is proposed and used in the simulations. Also, a grain growth rate equation accounting for both static and dynamic grain growth is implemented. The simulations were made using a 2D plane-strain model for constrained blow forming and an axisymmetric model for free bulging. These two models showed different features during the forming stages. However, the forming pressure-time curve and the thickness distribution obtained by both simulations explained well the deformation hardening induced by the grain growth during superplastic forming. This study shows that grain growth is an important factor in determining the material behavior during superplastic deformation.

• Journal of Mechanical Science and Technology
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• v.16 no.10
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• pp.1246-1252
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• 2002

Ultrafine grained (UFG) low carbon (0.15 wt.% C) steel produced by equal channel angula. pressing (ECAP) was tested for investigating the effect of load ratio on the fatigue crack growth rate. Fatigue crack growth resistance and threshold of UFG steel were lower than that of asreceived coarse grained steel. It was attributed to the less tortuous crack path. The UFG steel exhibited slightly higher crack growth rates and a lower △Kth with an increase of R ratio. The R ratio effect on crack growth rates and △Kth was basically indistinguishable at lower load ratio (R >0.3), compared to other alloys, which indicates that contribution of the crack closure vanishes. The crack growth rate curve for UFG steel exhibited a longer linear extension to the lower growth rate regime than that for the coarse grained as-received steel.