• Journal of the Korean Ceramic Society
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• v.31 no.10
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• pp.1240-1246
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• 1994

While sintering the Pb(Mg1/3Nb2/3)O3-PbTiO3-BaTiO3 system through solid-reaction route, pyrochlore(Pb3Nb4O13) phase while reduces the dielectric constant is inevitably formed. Substitution of Pb(Mg1/3Nb2/3)O3 with PbTiO3 and BaTiO3 can retard the occurrence of pyrochlore phase. The perovskite solid-solution without containing pyrochlore phase can be obtained when we consolidated the materials consisting of PbTiO3 and BaTiO3 at 1200℃ for 2 hours. The sintered body composed of 0.8Pb(Mg1/3Nb2/3)O3-0.1PbTiO3-0.1BaTiO3 composition showed the diffused phase transition(DPT) phenomena and the maximum value of dielectric constant at 0℃ (Tc') with the value of 1.3×104.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.47-53
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• 1998

Using Michael Reaction, commercially available 3-aminopropyltrimethoxysilane and N-[3-(trimethoxysilyl)propuyl]ethylenediamine were reacted with various Michael acceptors, ethyl acrylate, acrylonitrile, acrylamide, 2-cyanoethyl acrylate, 2-hydroxyethyl acrylate and 3-(trimethoxysilyl)propylmethacrylate, to the new aminosilanes. All compounds which are [3-(N-2-carboethoxyethyl)aminopropyl]triethoxysilane, [3-(N-2-cyanoethyl)aminopropyl]triethoxysilane, [3-(N-di-2-car-boethoxyethyl)aminopropyl]triethoxysilane, [3-N-di-cyanoethyl) aminopropyl]triethoxysilane, [3-(N-2-cyanoethoxypropionyl)aminopropyl]triethoxysilane, [3-(N-di-2-cyanoethoxypropionyl)aminopropyl]triethoxysilane, [3-(N-di-2-hydroxyethoxy propionyl)aminopropyl]triethoxysilane, [3-(N-2-amidoethyl)aminopropyl]triethoxysil-ane,｛3-[N-(N-di-2-cyanoethyl)ethyl]aminopropyl｝triethoxysilane and ｛3-[N-(3-trimethoxysilylpropyl)-2-methylpropionyl]aminopropyl｝triethoxysilane were succes-sfully prepared in 35-70% yields and which were identified with $^1{H}$-NMR and FT-IR spectroscopy.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1231-1234
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• 2007

This paper presents the overview of 3D video processing technologies for 3DTV such as 3D content generation, 3D video codec and video processing techniques for 3D displays. Some experimental results for 3D contents generation are shown in 3D mixed reality and 2D/3D conversion.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.66.2-66
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• 2000

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.28-33
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• 2006

La substituted perovskite $BiFeO_3$ have been prepared by a sol-gel method. Magnetic and structural properties of the powders were characterized with Mossbauer spectroscopy, XRD, SEM, and TG-DTA. The crystal structure is found to be a rhombohedrally distorted perovskite structure with the lattice constant $\alpha=3.985{\AA}\;and\;\alpha=89.5^{\circ}.\;Bi_{2/3}La_{1/3}FeO_3$ powders that were annealed at and above $600^{\circ}C$ have a single-phase perovskite structure. However, powders annealed at $900^{\circ}C$ have a typical perovskite structure with small amount of $Bi_2O_3$ phase. The Neel temperature of $Bi_{2/3}La_{1/3}FeO_3$ is found to be $680\pm3K$. The isomer shift value at room temperature is found to be 0.27 mm/s relative to the Fe metal, which is consistent with high-spin $Fe^{3+}$ charge states. Debye temperature far$Bi_{2/3}La_{1/3}FeO_3$ is found to be $305\pm5K$. The average hyperfine field $H_{hf}(T)$ of the $Bi_{2/3}La_{1/3}FeO_3$, shows a temperature dependence of $[H_{hf}(T)-H_{hf}(0)]/H_{hf}(0)=-0.42(T/T_N)^{3/2}-0.13(T/T_N)^{5/2}$ for $T/T_N<0.7$ indicative of spin-wave excitation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.34-38
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• 2016

This study aims to develop qualification criteria for training and establishing an expert pool of 3D printing operation experts and 3D printing development specialists in the emerging 3D printing industry. We investigate the domestic and international 3D printing industry, as well as 3D printing- related training institutions and quantity of test examinees. Utilizing competency analysis, this study examines the competencies and educational content of both 3D printing operation expert as well as 3D printing development specialists. In addition, a survey was conducted on the issue of institutionalization of qualification criteria for 3D printing operation expert and 3D printer development specialists. This study further proposes evaluation methods for qualification criteria for both 3D printing operation expert and 3D printer development specialists based on simulations of both written and performance tests. Based on the findings, this study proposes instructional program outlines as well as comprehensive guidelines for training and qualification processes for 3D printing operation expert and 3D printer development specialists.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.105-111
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• 1994

Intermediates, 1-benzyl-2-substituted-3-carboxaldehyde[I]-[II], were prepared by the reaction of 2-substituted indole-3-carboxaldehyde with benzyl chloride. Indolylacrylophenone derivatives[III]-[X] were prepared from 1-benzyl-2-substituted-3-carboxaldehyde with acetophenone derivatives. They are as follows; 3-(1'-benzylindole-3'-yl)-1acrylophenone [III] 3-(1'-benzylindole-3-yl)-1(p-methoxy)acrylophenone [IV] 3-(1'-benzylindole-3-yl)-1(p-bromo)acrylophenone [V] 3-(1'-benzylindole-3-yl)-1(p-chloro)acrylophenone [VI] 3-(1'-benzyl-2'-methylindole-3'-yl)-1-acrylophenone [VII] 3-(1'-benzyl-2'-methylindole-3'-yl)-1-(p-methoxy)acrylophenone [VIII] 3-(1'-benzyl-2'-methylindole-3'-yl)-1-(p-bromo)acrylophenone [VIII] 3-(1'-benzyl-2'-methylindole-3'-yl)-1-(p-chloro)acrylophenone [X]

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.667-672
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• 1998

Pyroelectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ ceramics prepared by the columbite precursor method have been investigated as a function of the sintering temperature in the range of $1000^{\circ}C$ to $1250^{\circ}C$. The $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ ceramics show typical relaxor ferroelectric behavior. The optimum condition for obtaining samples with high densities and improved pyroelectric properties occur at a sintering temperature of $1250^{\circ}C$ and sintering times of 2 hours. The $Pb(Mg_{1/3}Nb_{2/3}O_3-PbTiO_3$ ceramics show the possibility for pyroelectric sensors with pyrostat.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.478-481
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• 2000

Single phase $Pb(Mg_{1/3}Nb_{2/3})O_3$ ceramics doped by 10 mol% of electron donors such as $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$, were synthesized and their B-site cationic ordering structures were investigated by XRD and TEM. In the XRD patterns, only fundamental reflections were observed for the undoped $Pb(Mg_{1/3}Nb_{2/3})O_3$, while the (h/2 $\textsc{k}$/2ι/2)(h,$\textsc{k}$,ι all odd) superlattice reflections resulting from the 1:1 ordering induced unit cell doubling were also observed for the donor-doped $Pb(Mg_{1/3}Nb_{2/3})O_3$. In the TEM selected area diffraction patterns, the (h/2 k/2 l/2)(h,k,l all odd) superlattice reflection spots as well as the fundamental reflection spots were observed for all the samples, but the relative intensities of the superlattice reflection spots to the fundamental reflection spots were significantly enhanced by the donor-doping. In the TEM dark-field images, antiphase boundaries were observed only for the donor-doped $Pb(Mg_{1/3}Nb_{2/3})O_3$. It was therefore experimentally verified that doping by electron donors such as $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$, enhances the B-site cationic 1:1 ordering in $Pb(Mg_{1/3}Nb_{2/3})O_3$. These experimental results were interpreted in terms of the charge compensation mechanism.

• Journal of the Korean Ceramic Society
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• v.32 no.5
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• pp.582-586
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• 1995

The crystal structures of (Na0.3Sr0.7)(Ti0.7M0.3)O3 (M=Ta, Nb) compounds were determined using the Rietveld method. Due to the tilting of a oxygen octahedron, (Na0.3Sr0.7)(Ti0.7Nb0.3)O3 had a superlattice of doubled a, b and c of simple perovskite. The crystal structure of (Na0.3Sr0.7)(Ti0.7M0.3)O3 was tetragonal with a space group 14/mmm. The crystal structure of (Na0.3Sr0.7)(Ti0.7M0.3)O3 was a cubic with space group Pm3m, in which no tilting of oxygen octahedron was observed. The difference in the oxygen tilting of these two materials was due to the larger covalency of Nb-O bond than that of Ta-O bond, which induced a strong $\pi$Nb0 bonding in (Na0.3Sr0.7)(Ti0.7M0.3)O3. Therefore, the higher transition temperature of (Na0.3Sr0.7)(Ti0.7M0.3)O3 could be related to the larger tilting of oxygen octahedron.