• Journal of Magnetics
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• v.10 no.1
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• pp.28-32
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• 2005

The magnetic properties and ordering behavior of Nb-doped FePt alloy films prepared by dc-magnetron sputtering were investigated. It was found that Nb addition retarded the ordering reaction from the disordered face-centered-cubic (fcc) Al phase to the ordered face-centered-tetragonal (fct) L1₀ phase. The tetragonality (c/a ratio) of the ordered fct L1₀ phase increased with the Nb concentration. Nb addition hampered c-axis contraction during ordering, probably because the larger Nb atoms occupy Pt sites. Consequently, the coercivity and magnetocrystalline anisotropic energy of Nb-doped FePt alloy films are lower than those of un-doped FePt film under equivalent annealing conditions.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.3
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• pp.87-101
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• 2013

The purpose of this paper is to analyze supplier's optimal decision of the buyback price facing irrational retailers. It has been known that retailers show irrational ordering behaviors, such as pull-to-center effect. We model the retailer's pull-to-center behavior and derive the supplier's optimal buyback price considering the retailer's bounded rationality. The result shows that the supplier's profit can be significantly improved exploiting the retailer's irrationality in the ordering behavior.

• Korean Journal of Crystallography
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• v.12 no.2
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• pp.81-87
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• 2001

We have studied the effect of sintering temperature and time on the cation ordering and second phase formation in Ba(Mg/sub 1/3/Nb/sub 2/3/)O₃(BMN) microwave ceramics by using transmission electron microscopy. The relationship between the structural-chemical behavior arid microwave dielectric properties has also been investigated. It is revealed that according to the sintering conditions the BMN ceramics show very diverse local ordering behavior, such as the development of domain twinning and "core-shell"-structured grains and the formation of local disordered domains, though having 1 : 2 cation ordering structure basically. The disordered structure is found in Mg-excess region. Such local chemical variation seems to be caused by the formation of BaNb₂O/sub 6/-like second phase in its neigh-boring grain boundary. The microwave dielectric quality factor of the ceramics decreases greatly with the increase of the structural-chemical inhomogeneity and diversity.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.839-845
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• 1995

The structural and dielectric properties of Pb(Mg1/3Nb2/3)O3 ceramics substituted by Nd3+, La3+, K+ and Na+ were studied over 0~50 at.% substituent content. The 1 : 1 ordering behavior of Mg2+ and Nb5+ ions in the B site sublattice was observed in Nd3+-and La3+-modified compounds. The degree of ordering was increased with Nd3+, La3+ content in the compounds. But K+-or Na+-modified compounds did not exhibit the ordering behavior. This was explained by charge and size effect of A and B site cations and oxygen vacancies. As the mole fractions of substituent increased, the maximum values of dielectric constants were rapidly decreased and the phase transitions were broadened. Phase transition temperature was correlated with the covalency of A-O and B-O bonding.

• Korean Journal of Metals and Materials
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• v.50 no.10
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• pp.703-710
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• 2012

The effects of the ordering reaction on high temperature mechanical behavior is investigated by tensile tests at $2{\times}10^{-2}/s-3.3{\times}10^{-5}/s$ up to $745^{\circ}C$. The tensile deformed region is examined by differential scanning calorimeter (DSC), TEM, and high resolution neutron diffraction (HRPD). The results showed that a plateau of tensile strength appeared at $150-500^{\circ}C$ whereas the elongation minimum occurred at about $600^{\circ}C$. This suggests that the occurrence of a plateau does not cause the elongation minimum. The temperature of the elongation minimum decreases with the strain rate. HRPD results show a lattice contraction in the tensile deformed specimen at the temperature of the plateau occurring region. The plateau of tensile strength, the lattice contraction, and the occurrence of serration appeared in the same temperature region.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.211-211
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• 2012

Using spin-polarized density-functional theory calculations, we find that the existence of either Peierls instability or antiferromagnetic spin ordering is sensitive to hydrogen passivation near the step. As hydrogens are covered on the terrace, the dangling bond electrons are localized at the step, leading to step-induced states. We investigate the competition between charge and spin orderings in dangling-bond (DB) wires of increasing lengths fabricated on an H-terminated vicinal Si(001) surface. We find antiferromagnetic (AF) ordering to be energetically much more favorable than charge ordering. The energy preference of AF ordering shrinks in an oscillatory way as the wire length increases. This oscillatory behavior can be interpreted in terms of quantum size effects as the DB electrons fill discrete quantum levels.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.2
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• pp.101-127
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• 2016

Irrational ordering decisions of supply chain members have been gaining growing importance in the area of supply chain management. Irrational ordering behaviors that deviate from the profit maximizing decisions in the newsvendor settings have observed with human experiments in recent research. These behaviors can be modeled with several typical decision bias elements. This bias in ordering decisions affects the performance of supply chain contracts designed based on the assumption that the supply chain members make optimal decisions, making it necessary to design supply chain contracts by considering the irrationality. The purpose of this research is to derive a method to design the revenue sharing contract that considers human irrationality in ordering decisions. This research considers a simple two-echelon supply chain consisting of one supplier and one retailer, where the supplier is assumed to be perfectly rational while the retailer making newsvendor type ordering decisions displays irrational ordering behaviors. Under this environment, this research analytically models the revenue sharing contract to maximize the total supply chain profit or the supplier's own profits while considering the three decision bias patterns of the retailer, which include the pull-to-center effect, the prospect theory, and the increased subjective sensitivity to the revenue sharing ratio. Irrationality parameters are measured through human experiments based on which and through numerical simulations, we showed that significant improvements in the supply chain performance can be achieved.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.12-12
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• 2002

Lanthanum manganites have been extensively studied for the application to magnetic devices since the colossal magnetoresistance of these compounds has been observed [1]. The critical temperatures, Tc, of manganites La/sub 0.7/Ca/sub 0.3-x/Ba/sub x/MnO₃ increased as the content of Ba increased except the abrupt jump near the critical concentration. The step like behavior of the critical temperature for a similar compound has been known to be related to the structural phase transition [2]. To understand the step like behavior of Tc, the EXAFS technique is applied to the La/sub 0.7/Ca/sub 0.3-x/Ba/sub x/MnO₃ compound system. The ordering between the manganese and oxygen was examined by this method. The EXAFS analysis shows that the coordination numbers were not changed before and after the phase transition, the bonding distance between manganese and oxygen is about 1.94 ± 0.02 Å, which is consistent with other work [3] and the Debye waller parameters were about σ²= 0.0037 ± 0.0005 Ų for x=0.0 and x=3.0, respectively. The value of Debye-Waller parameter for x=0.09 is about σ² = 0.0050 ± 0.0005 Ų in about phase transition concentration. Based on the Debye-Waller parameters, it is shown that the ordering between manganese and oxygen is significantly reduced near the phase transition concentration.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.207-208
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• 2006

Here, we discuss various thermodynamic factors that affect the design of nanomaterials based on block copolymers. It is well known that the ordering behavior is determined by composition, chain size N, and the ubiquitous Flory. However, the recent discovery of ordering upon heating, immisibility loops, and baroplasticity addresses a clear need for further microscopic interpretation of such. in order to help to design nanomaterials at aimed purposes. Employing a perturbed hard sphere chain model, the molecular factors such as self and cross-interactions, free space distribution, and directional interactions are incorporated in. It is shown that not only typical ordering phenomena, but also the recent observations just mentioned are all described through this unified way.

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.187-194
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• 1998

InGaAsP epitaxial layers lattice matched to InP were grown at 600 and $620^{\circ}C$ by low pressure metalorganic chemical vapor deposition. Solid phase composition of group III was controlled by the diffusion flux gas phase to the reachion surface. For the case of group V, the difference of As and P vapor pressure and pyrolysis efficiency of $PH_3$and $AsH_3$ mainly determined their in corporation into solid. An abnormal behavior of peak energy shift was observed below 75K in temperature variant photoluminescence study. This abnormal behavior was explained by the difference in order of ordering which makes spatial variation of energy gap in InGaAsP layer and this explanation was supported by the analyses of transmission electron microscopy and transmission spectroscopy.