• Bulletin of the Korean Chemical Society
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• 제23권1호
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• pp.48-52
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• 2002

Using several molecular modeling programs we have performed computer simulations to investigate the complexation behaviors of an ester derivative of p-tert-butylcalix[5]arene (1e) toward a variety of butylammonium ions. Semi-empirical AM1 method was used for calculating the binding energies and the formation enthalpies. MM and CVFF forcefields for molecular mechanics calculations were adapted to express the complexation energies of the host. Molecular dynamics were performed to the calculated complex systems to simulate the ionophoric behavior of the host-guest complexes. The absolute Gibbs free energies of the host (1e) complexed with four kinds of butylammonium ions have been calculated using the Finite Difference Thermodynamic Integration (FDTI) method in Discover. Calculation results show that the trend in complex formation is n-$BuNH_3^+$ > iso-$BuNH_3^+$ >> sec-$BuNH_3^+$ > tert-$BuNH_3^+$, which is in good agreement with the experimental results.

• Corrosion Science and Technology
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• 제3권2호
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• pp.54-58
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• 2004

Effects of texture on the electrochemical behaviors of single grains in polycrystalline zinc were investigated using a capillary-based micro-droplet cell. Pontiodynamic sweeps and capacity measurements were carried out in pH 9 borate buffer solution. The cyclic voltammograms and the capacity measurements on single grains with different crystallographic orientations in polycrystalline Zn showed a strong dependence of oxide growth on crystallographic grain orientation. The total charge consumed for oxide formation and the inverse capacity increased with an increase of surface packing density of grain. suggesting the oxide formation was greater on grains with higher surface packing density.

• 한국염색가공학회지
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• 제23권3호
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• pp.163-168
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• 2011

In this article, we synthesized an azo dye rotaxane containing bis(8-hydroxyquinoline) group and its polymeric metal complex with zinc. The azo dye rotaxane exhibits high pH sensitivity, solvatochromism and zinc (II) ion sensings in aqueous solution. These behaviors came from the tautomeric equilibrium between azo-hydrazone tautomers and the formation of extended conjugation. The structure of polymeric zinc complexed dye rotaxane was confirmed with NMR and FT-IR measurements. The existence of CD rings, provided by dye rotaxane formation, was found to be very beneficial in improving aqueous solubility of polymeric metal complex.

• International Journal of Automotive Technology
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• 제6권4호
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• pp.421-427
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• 2005

This work analyzes the behaviors of aerated lubricant in the gap between con-rod bearing and journal. It is assumed that the film formation with aerated lubricant is influenced by the two major factors. One is the density characteristics of the lubricant due to the volume change of lubricant for the formation of bubbles and the other is the viscosity characteristics of the lubricant due to the surface tension of the bubble in the lubricant. These two major factors surprisingly increase the load capacity in some ranges of bubble sizes and densities. Modified Reynolds' equation is developed for the computation of fluid film pressure with the effects of aeration ratio in the lubricant. From the calculated load capacity by solving modified Reynolds' equation, journal locus is computed with Mobility method after comparing it with the applied load at each time step. The differences of journal orbits between aerated and pure lubricants are shown in the computed results.

• 한국분말재료학회지
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• 제10권5호
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• pp.337-343
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• 2003

Nanostructured Cu-$Al_2O_3$ composite powders were synthesized by thermochemical process. The synthesis procedures are 1) preparation of precursor powder by spray drying of solution made from water-soluble copper and aluminum nitrates, 2) air heat treatments to evaporate volatile components in the precursor powder and synthesis of nano-structured CuO + $Al_2O_3$, and 3) CuO reduction by hydrogen into pure Cu. The suggested procedures stimulated the formation of the gamma-$Al_2O_3$, and different alumina formation behaviors appeared with various heat treating temperatures. The mean particle size of the final Cu/$Al_2O_3$ composite powders produced was 20 nm, and the electrical conductivity and hardness in the hot-extruded bulk were competitive with Cu/$Al_2O_3$ composite by the conventional internal oxidation process.

• 한국결정학회지
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• 제11권4호
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• pp.200-206
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• 2000

In a 200 mm Cz-Si crystal, a macroscopic fluctuation in pulling rate was intentionally introduced then the variations of the pulling rate and the formation behaviors of grow-in defects were compared. The diameters of the OSF-ring and the FPD area were affected by the fluctuation in the region above 1100℃. The COP density depended on the diameter of the OSF-ring. ΔOi and BMD were affected by the fluctuation in the region near 1000Δ. As the result, when a macroscopic fluctuation in pulling rate is introduced, the quality of crystal in the region of 150 mm from the growth interface should be reviewed carefully because it can be affected by the fluctuation.

• 한국세라믹학회지
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• 제29권6호
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• pp.451-458
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• 1992

Dense glass-ceramics for low firing temperature substrate were prepared by addition of CeO2 flux to the glass of MgO-Al2O3-SiO2 system. Glass powders were fabricated by melting at 150$0^{\circ}C$ and ball milling. Glass powder compacts were sintered at 800~100$0^{\circ}C$ for 3h. The crystallization and the shrinkage behaviors of glass powder compacts were analyzed by XRD, DTA and TMA. The shrinkage of glass powder compact increased with increasing the amount of CeO2. Because the softening temperature decreased and the crystallization temperature increased with increasing the amount of CeO2. Apparently, addition of CeO2 prevented formation of $\mu$-cordierite phase from the glass-ceramics and improved formation of $\alpha$-cordierite phase. Therefore crystallization properties were enhanced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1883-1884
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• 2008

This paper presents a framework for decentralized control of self-organizing swarm agents based on the artificial potential functions (APFs). The framework explores the benefits by associating agents based on position information to realize complex swarming behaviors. A key development is the introduction of a set of association rules by APFs that effectively deal with a host of swarming issues such as flexible and agile formation. In particular, this paper presents an association rule for swarming that requires less movements for each agent and compact formation among agents. Extensive simulations are presented to illustrate the viability of the proposed framework.

• 품질경영학회지
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• 제29권4호
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• pp.54-64
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• 2001

Service industries are rapidly increased and the environment of service is also changing in healthcare settings. Those make them change their management strategies and carry out many researches. Till now, single-item behavioral intention scale or direct measuring has some limitations that we have to consider its efficiency and it is difficult to explain phenomena of broad part in the process of determining behavioral intentions. In this paper, we examine the dimensionality of healthcare service in Korea through the multi-item behavioral intention scale. In addition, we are going to investigate the nature of the relationship between service quality perceptions which have unique construct, and consumer satisfaction judgements in the formation of consumers' behavioral intentions. we are going to conclude that the linear combination model of service quality and customer satisfaction can describe the process of formation of customers' behavioral intentions best and provide some managerial implications to decision makers for redistribution of materials and human resources.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3108-3113
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• 2008

This paper investigated the behaviors of combustion characteristics at part load condition with various intake charge motions induced by the port masking schemes in the CVVT (Continuously Variable valve Timing) engine. Time resolved in-cylinder and exhaust emissions were measured by the fast response HC and NOx analyzers to examine their formation mechanisms and behavior characteristics. As a result, in-cylinder HC decreased with the advanced intake valve timings but HC at the exhaust port increased due to the worse combustion stabilities. However HC reduction could be achieved by the application of the port maskings with a enhancement of the engine stability. NOx also decreased with early intake timings by internal EGR but increased with the charge motion controls which enhance the combustion behavior.