• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.579-580
• /
• 2006

Ferroelectric PZT (70/30) thick films were fabricated by the screen printing method. And the PZT (30/70) Precusor solution were infiltrated by the spin-coating method on the PZT thick films to obtain a densification. All PZT thick films were sintered at $1050^{\circ}C$ for 10min. Structural properties, such as crystalline structure, microstructures and compositional ratio, of PZT thick films were investigated with the variation of the number of sol coatings using XRD, SEM and EDS, respectively. All PZT thick films exhibited a perovskite polycrystalline structure without a pyrochloer phase. The thickness of PZT thick films, 4-times screen-printed, was approximately 60fm. And the densification of the PZT thick films increased with increasing the number of sol coatings.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.1245-1246
• /
• 2006

Ferroelectric PZT (70/30) thick films were fabricated by the screen printing method. And the PZT (30/70) precusor solution were infiltrated by the spin-coating method on the PZT thick films to obtain a densification. All PZT thick films were sintered at $1050^{\circ}C$ for 10 min. Structural properties, such as crystalline structure, microstructures and compositional ratio, of PZT thick films were investigated with the variation of the number of sol coatings using XRD, SEM and EDS, respectively. All PZT thick films exhibited a perovskite polycrystalline structure without a pyrochloer phase. The thickness of PZT thick films, 4-times screen-printed, was approximately $60{\mu}m$. And the densification of the PZT thick films increased with increasing the number of sol coatings.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1993.06a
• /
• pp.1137-1140
• /
• 1993

A dynamic-structure system is one that has the flexibility to change the system configuration automatically so as to operate in an optimal manner. A conceptural model for a dynamic-structure system is presented in this paper. In this model, the interchangeable components of the overall system are grouped together. Their activity levels are evaluated by an intelligent preprocessor that is associated with the group. A knowledge-based task distribution system evaluates the activity levels and makes decisions as to how the components operating below capacity should be shared with workcells that have similar components that are overloaded. Associated decision making can be effected through fuzzy logic and particularly the compositional rule of inference. A simulation example is given to illustrate the application of dynamic structuring.

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1705-1706
• /
• 2006

Ferroelectric PZT (70/30) thick films were fabricated by the screen printing method. And the PZT (30/70) precusor solution were infiltrated by the spin-coating method on the PZT thick films to obtain a densification. All PZT thick films were sintered at $1050^{\circ}C$ for 10 min. Structural properties, such as crystalline structure, microstructures and compositional ratio, of PZT thick films were investigated with the variation of the number of sol coatings using XRD, SEM and EDS, respectively. All PZT thick films exhibited a perovskite polycrystalline structure without a pyrochloer phase. The thickness of PZT thick films, 4-times screen-printed, was approximately $60{\mu}m$. And the densification of the PZT thick films increased with increasing the number of sol coatings.

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.805-809
• /
• 1995

In order to widen the band-width of ferrite absorber, compositional effect on the complex permeability of Ni-Zn ferrite and the structure of grid absorber were studied. From the experimental results, we could determine the optimum composition composition of Ni-Zn ferrite and the structure of grid absorber. Also, we manufactured grid absorber and investigated its microwave absorbing characteristics. Calculation shows that the ferrite frid absorber suppresses reflection ${\leq}-20dB$ from 30 MHz to 700 MHz and the conventional ferrite tile absorber suppresses reflection ${\leq}20dB$ in the frequency range of 30 MHz-400 MHz. It was found that the microwave absorbing performance of the ferrite grid absorber was superior to the ferrite tile absorber.

• Journal of the Korean Ceramic Society
• /
• v.31 no.2
• /
• pp.155-160
• /
• 1994

PZT ceramics substituted by La3+ and Nd3+ were fabricated according to the formula: [Pb1-x(La or Nd)x][Zr0.58Ti0.42]1-x/4$\square$x/4O3(x=0.00, 0.02, 0.05, 0.08, 0.15, 0.20). The crystal structure and microstructure were investigated by XRD and SEM. It was observed that the phase transitions among rhombohedral, tetragonal, and cubic symmetry occured as the substitutional quantity increased. Dielectric constant, dissipation factor and piezoelectric coefficient (d33), of each sample were measured. The dielectric properties were changed as the substitutional quanity of rare earth ion increased. These changes could be explained by crystal structure and compositional fluctuaction. Its d33 was higher at tetragonal region near to phase boundry between rhombohedral and tetragonal, which was explained by reorientation of domain wall.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.6 no.3
• /
• pp.368-376
• /
• 1996

$LiNbO_{3}$ single crystals (undoped, 5 mol% MgO-doped and 5 mol% ZnO-doped) were grown by the floating zone method which has the characteristics of a compositional homogeneity and uniform distribution of the dopants. The optimum growth condition was established experimentally and the defect structures such as domain structure, dislocation structure, slip band, and microtwins were characterized using a microscopic method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.91-91
• /
• 2008

$SnO_2-B_2O_3-P_2O_5$ system were prepared by melt-quenching technique in the compositional series containing 50, 55 aod 60mol.% of $SnO_2$. A large glass-forming region was found at the phosphate side of the ternary system with homogeneous glasses containing up to 5-25mol.% of $B_2O_3$. For these glasses, thermal expansion coeffient($\alpha$), glass transition temperature(Tg), and glass softening temperature(Ts), were determined. The values a decrease with increasing $B_2O_3$ content, while Tg and Ts increased. The reason for the observed changes is local structure of the glasses. Local structure of the glasses was investigated by Raman and FT-IR measurements, suggesting that the number of bridging oxygens decreased whereas the non-bridging oxygen concentration increased with increasing $SnO_2$ content in the glasses.

• Journal of Magnetics
• /
• v.11 no.1
• /
• pp.25-29
• /
• 2006

Recent experiments have demonstrated high TMR ratios in MTJs with the MgO barrier [1,2]. The CoFeB/MgO/CoFeB junctions showed better properties than the CoFe/MgO/CoFe junctions because the MgO layer had a good crystalline structure with (001) texture and smooth and sharp interface between CoFeB/MgO [3]. The amorphous CoFeB with 20 at%B starts the crystallization at $340^{\circ}C$ [4] and this crystallization of the CoFeB helps obtaining the high TMR ratio. In this work, the compositional changes in the MgO barrier and at the interface of CoFeB/MgO/CoFeB after the CoFeB crystallization were studied in annealed MTJs. XPS depth profiles were utilized. TEM analyses showed that the MgO barrier had (100) texture on CoFeB in the junctions. B in the bottom CoFeB layer diffused into the MgO barrier and B-oxide was formed at the interface of CoFeB/MgO/CoFeB after the CoFeB crystallization.

• Preventive Nutrition and Food Science
• /
• v.3 no.3
• /
• pp.211-215
• /
• 1998

Preparative isolation of lipid granules from Fhodotorula glutinis, which has been studied for long time to produce edible lipids, was carried out by flotation method in Ficoll-Linear density gradient. When the isolated lipid granules were suspended in a series of solutions containing varying concentration of osmotic stabilizer (sorbitoal and mannitol) ranging from 0.8M to 0M, the lipid granules appeared to be disrupted at a concentration between 0.8M and 0.7, and again at a concentration below 0.1M, suggesting that lipid granules have a membraneous structure and that at least two types of lipid granules are present. Compositional analysis of lipids from lipid granules revealed that lipids are composed mainly of neutral lipids (87.8% of total lipids), predominantly as triacylglycerols (71.89%). Marked differences were observed inphospholipids between lipids of lipid granules and those of whole cells . The major components of phospholipids in lipid granules and inwhole cells are phosphatidylcholine(38.6%) and phosphatidylserine(42.8%), respectively. In addition, significant differences were also observed in the fatty acid composition of phospholipids. As phospholipids are important structural components of membranes, these differences lead to the suggesting that the membrane of lipid granules may be distinct functionally and structurally from other membranes of yeast cells. The major fatty acid components of neutral lipidss of whole cells and lipid granules are palmitic , oleic and linoleic acid. However , degreeof fatty acid unsaturation of neutal lipids of lipid granules was much lower than that of neutral lipids of whole cells.