• Journal of the Korean Ceramic Society
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• v.33 no.4
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• pp.455-463
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• 1996

Aluminium nitride (AlN) powder was prepared by using aluminium (III) complexes with dibasic carboxylate ligands(adipato)(hydroxo) aluminium(III) and (hydroxo)(succinato)aluminium (III) as a precursor. The AlN pow-der was obtained by calcining the complexes without mixing any carbon source under a flow of ammonia at 120$0^{\circ}C$ Contary to the conventional carbothermal reduction and nitridiation the process of decarboniza-tion of the residual carbon was not required because of the reaction of ammonia with carbon at temperature >100$0^{\circ}C$. Fine AlN powder was also prepared by calcining a mixture of an (adipato)(hydroxo)aluminium(III) complex and carbon under a flow of nitrogen at 140$0^{\circ}C$ The AlN powders prepared were ultrafine and their morphology was almost the same as that of powders of two precursors.

• Carbon letters
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• v.7 no.4
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• pp.245-248
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• 2006

Thin films of carbon-nano materials (CNMs) of different morphology have been successfully deposited on ceramic substrate by CVD at temperatures $800^{\circ}C$, $850^{\circ}C$ and $900^{\circ}C$ using plant based oils in the presence of transition metal catalysts (Ni, Co and Ni/Co alloys). Based on the return and insertion loss, microwave absorption properties of thin film of nanocarbon material are measured using passive micro-Strip line components. The result indicates that amongst CNMs synthesized from oil of natural precursors (mustered oil - Brassica napus, Karanja oil - Pongamia glabra, Cotton oil - Gossipium hirsuta and Neem oil - Azadirachta indica) carbon nano fibers obtained from neem's seed oil showed better microwave absorption (~20dB) in the range of 8.0 GHz to 17.90 GHz.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.1
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• pp.1-4
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• 2000

Thin films of hydrogenated amorphous silicon carbide compounds ($a-Si_{x}C_{1-x}:H$) of different compositions were deposited on Si substrate by RF plasma-enhanced chemical vapor deposition (PECVD). Experiments were carried out using silane (SiH$_4$) and methane ($CH_4$) as the gas precursors at 1 Torr and at a low substrate temperature ($250^{\circ}C$). The gas flow rate was changed with the other parameters (pressure, temperature, RF power) fixed. The substrate was Si(100) wafer and all of the films obtained were amorphous. The bonding structure of $a-Si_{x}C_{1-x}:H$films deposited was investigated by X-ray photoelectron spectroscopy (XPS) for the film compositions. In addition, the surface morphology of films was investigated by atomic force microscopy (AFM).

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.483-486
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• 2021

Catalytic ozonation of methyl ethyl ketone (MEK) has been examined over mesoporous MnO_x/Al₂O₃ (MA) catalysts developed by a solvent deficient method using two different manganese precursors including manganese chloride (C) and manganese sulfate (S) at room temperature. The maximum catalytic activities of MA with C (MEK removal efficiency and ozone decomposition of 98.4 and 93.7%, respectively) were higher than those of MA with S (MEK removal efficiency and ozone decomposition of 96 and 68%, respectively). Also the catalytic stability of MA with C was much higher than that of MA with S. The physico-chemical properties of catalysts are well correlated with the activity results, which confirmed that fine dispersion of MnO_x species with high ratios of Mn³⁺/Mn⁴⁺ and more acid sites are attributed to the higher catalyst stability for the MA-C catalyst.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.285-303
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• 1999

Thin films of hydrogenated amorphous silicon carbide compounds (a-SixC1x:H) of different compositions were deposited on Si substrate by RF plasma-enhanced chemical vapor deposition (PECVD). Experiments were carried out using silane(SiH4) and methane(CH4) as the gas precursors at 1 Torr and at low substrate temperature (25$0^{\circ}C$). The gas flow rate was changed with every other parameters (pressure, temperature, RF power) fixed. The substrate was Si(100) wafer and all of the films obtained were amorphous. The bonding structure of a-SixC1x:H films deposited was investigated by X-ray photoelectron spectroscopy (XPS) for the film compositions. In addition, the surface morphology of films was investigated by atomic force microscopy (AFM).

• Progress in Superconductivity and Cryogenics
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• v.11 no.4
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• pp.20-24
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• 2009

YBCO coated conductors (CC) on the $CeO_2$-buffered IBAD-MgO template were fabricated by metal-organic deposition (MOD) Process with Ba-trifluoroacetate and fluorine-free Y and Cu precursor materials. The precursor solution was coated on $CeO_2$-buffered IBAD MgO templates using the multiple dip-coating method, decomposed into inorganic precursors by pyrolysis up to $400^{\circ}C$ within 3 h, and finally fired at $740{\sim}800^{\circ}C$ in a reduced oxygen atmosphere. Microstructure, texture, and superconducting properties of YBCO films were found highly sensitive to both the firing temperature and time. The high critical current density ($J_C$) of $1.15\;MA/cm^2$ at 77.3K in the self-field could be obtained from $1\;{\mu}m$ thick YBCO CC, fired at $740^{\circ}C$ for 3.5 h, implying that high performance YBCO CC is producible on IBAD MgO template. Further enhancement of $J_C$ values is expected by improving the in-plane texture of $CeO_2$-buffer layer and avoiding the metal substrate contamination.

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.126-131
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• 1990

The novel N-phenyl-2-furohydrazonyl chloride 4A and its p-nitro analog 4B have been prepared and identified. The cycloaddition reactions of nitrilimines 5A and 5B, derived by base catalyzed dehydrochlorination of 4A and 4B respectively, to a variety of dipolarophiles were investigated. The results showed that 4A and 4B are usuful precursors for synthesis of differently substituted 3-(2-furyl)-2-pyrazoline derivatives and their pyrazoles and analogs.

• Bulletin of the Korean Chemical Society
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• v.28 no.9
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• pp.1463-1466
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• 2007

Single phases of multi-component oxides films, ZrTiO4 and Ta2Zr6O17, could be synthesized by using the combinatorial approach through surface sol-gel route, coating the appropriate mole ratio of 100 mM zirconium butoxide, tantalum butoxide and titanium butoxide precursors on Pt/Ti/SiO2/Si (100) substrate, following pyrolysis at 450 oC, and annealing them at 770 oC. Both the films and bulks of ZrTiO4 and Ta2Zr6O17 showed very stable dielectric properties in temperature range, ?140 to 60 oC, and frequency range, 100 Hz to 1 MHz, promising their applications in wide range of temperatures and frequencies. The dielectric constants of the films were lower and a little more dependent on frequency than those of the bulks. The reduction of dielectric property in the film was mainly due to the interfacial effects that worked as series and parallel-connected capacitances toward the substantial film capacitance.

• Korean Journal of Materials Research
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• v.19 no.8
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• pp.412-416
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• 2009

In this study, 3 mol% yttria-tetragonal zirconia polycrystal (3Y-TZP) nanoparticles were synthesized by the glycothermal method under various reaction temperatures and times. The co-precipitated precursor of 3Y-TZP was prepared by adding $NH_4OH$ to starting solutions, and then the mixtures were placed in an autoclave reactor. Tetragonal yttria-doped zirconia nanoparticles were afforded through a glycothermal reaction at a temperature as low as $220^{\circ}C$, using co-precipitated gels of $ZrCl_4$ and $YCl_3{\cdot}6H_2O$ as precursors and 1,4-butanediol as the solvent. The synthesized 3Y-TZP particles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman spectroscopy. The 3Y-TZP particles have a stable tetragonal phase only at glycothermal temperatures above $200^{\circ}C$. To investigate phase transition, the 3Y-TZP particles were heat treated from 400 to $1400^{\circ}C$ for 2 h. Raman analysis indicated that, after heat treatment, the tetragonal phase of the 3Y-TZP particles remained stable. The results of this study, therefore, suggest that 3Y-TZP powders can be prepared by the glycothermal method.

• Journal of the Korean Chemical Society
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• v.67 no.6
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• pp.429-440
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• 2023

1,1-Dialkyl-2,5-bis(trimethylsilylethynyl)-3,4-diphenylsiloles (R=Et, i-Pr, n-Hex; 3a-c) were prepared and utilized as anode active materials for lithium-ion batteries; 3a was also used as a filler for the solid-state electrolytes (SSE). Siloles 3a-c were prepared by substitution reactions in which the two bromine groups of 1,1-dialkyl-2,5-dibromo-3,4-diphe- nylsiloles, used as precursors, were substituted with trimethylsilylacetylene in the presence of palladium chloride, copper iodide, and triphenylphosphine in diisopropylamine. Among siloles 3a-c, 3a had the best electrochemical properties as an anode material for lithium-ion batteries, including an initial capacity of 758 mAhg^-1 (0.1 A/g), which was reduced to 547 mAhg^-1 and then increased to 1,225 mAhg^-1 at 500 cycles. A 3a-composite polymer electrolyte (3a-CPE) was prepared using silole 3a as an additive at concentrations of 1, 2, 3, and 4 wt.%. The 2 wt.% 3a-CPE composite afforded an excellent ionic conductivity of 1.09 × 10^-3 Scm^-1 at 60℃, indicating that silole 3a has potential applicability as an anode active material for lithium-ion batteries, and can also be used as an additive for the SSE of lithium-ion batteries.