• Journal of the Korean Chemical Society
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• v.30 no.6
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• pp.526-531
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• 1986

The stability constants of 1,15-diaza-3,4:12,13-dibenzo-5,8,11-trioxacycloheptadecane (NenOdien H$_4$, L) with transition metal ions such as $Co^{2+},\;Ni^{2+},\;Cu^{2+},\;and\;Zn^{2+}$ have been determined by potentiometry in 95% methanol solution at 25$^{\circ}$C. The complex formation of the NenOdien $_4$ with the transition metal ions depends on the basicity of the donor atoms. The order of complex stability was Co(II) < Ni(II) < Cu(II) > Zn(II). The geometries of the complexes in solid state were discussed by visible-near infrared and infrared spectrophotometry, elemental analysis and electro-conductivity. The results suggest that the geometries of the solid complexes are octahedral for $[CoL_2(OH_2)Cl]Cl{\cdot}2H_2O$, $[NiL_2(OH_2)Cl]Cl{\cdot}2H_2O$, and $[ZnLCl_2]{\cdot}\frac{1}{2}H_2O$ and square pyramidal for [CuLCl]Cl, respectively.

• Advances in Traditional Medicine
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• v.2 no.1
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• pp.36-40
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• 2002

Effects of hydrogen peroxide $(H_2O_2)-induced$ neurotoxicity were investigated in cultured newborn rat spinal dorsal root ganglion (DRG) neurons after DRG neurons were treated in the media containning various concentrations of $H_2O_2$. In addition, the protective effect of Herba Epimedii (HE) extract against $H_2O_2-induced$ neurotoxicity was examined. Cytotoxic values were determined by the cell viability of living cells using 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay. In the present study, exposure of neurons to $H_2O_2$ resulted in a significant cell death in a dose- and time-dependent manners in cultured DRG neurons. The decrement of cell viability by $H_2O_2$ was blocked by HE. These results suggest that the neuroprotective effect of HE against $H_2O_2-induced$ cytotoxicity may result from the prevention of injury induced by $H_2O_2$.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.218-224
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• 2014

In order to explore new coordination frameworks with novel designed 3-nitrophthalic acid and the same N-donor ancillary ligand, a series of novel coordination complexes, namely, $[Cd_2(3-NPA)_2(TBZ)_2(H_2O)_2]{\cdot}2H_2O$(1), $[Zn_2(3-NPA)_2(TBZ)_2]$(2), $[Zn_2O(3-NPA)(TBZ)(H_2O)]_n$(3), $[Co(3-NPA)(TBZ)(H_2O)]_n$(4) (3-$NPAH_2$ = 3-nitrophthalic acid), have been hydrothermally synthesized through the reaction of 3-nitrophthalic acid with divalent transition-metal salts in the presence of N-donor ancillary coligand (TBZ = thiabendazole). As a result of various coordination modes of the versatile 3-$NPAH_2$ and the coligand TBZ, these complexes exhibit structural diversity. X-ray structure analysis reveals that 1 and 2 are 0D molecular rings, while 3 and 4 are one-dimensional (1D) infinite chain polymers. And the weak O-H${\cdots}$O hydrogen bonds and C-H${\cdots}$O nonclassical hydrogen bonds as well as ${\pi}-{\pi}$ stacking also play important roles in affecting the final structure where complexes 1, 3 and 4 have 3D supramolecular architectures, while complex 2 has a 2D supramolecular network. Also, IR spectra, fluorescence properties and thermal decomposition process of complexes 1-4 were investigated.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.735-739
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• 1995

An experiment was carried out to investigate the effect of $Na_{2}O$ additive on the magnetic and physical properties of $SrZn_{2}-W$ type hexagonal ferrite. The specimens were prepared by the conventional manufacturing methods without atmosphere control. It was found that the magnetic properties of SrO.2ZnO.$8Fe_{2}O_{3}$ are considerably improved on adding 1.5wt% $Na_{2}O$. Theoptimum condition of making magnet with suitable properties are as follows : chemical analysis composition : $Sr^{2+}_{0.852}Zn^{2+}_{1.721}Na^{+}_{0.301}Fe^{2+}_{0.723}Fe^{3+}_{15.703}O_{27}$ ; semisintering condition : $1300^{\circ}C\;{\times}\;1h$ in air ; sintering condition : $1250^{\circ}C\;{\times}\;0.5h\;T_{c}=371^{\circ}C,\;H_{A}=1091.5kA/m,\;K_{A}=2.13{\times}10^{5}J/m^{3}\;and\;n_{B}=31.8\mu\textrm{B}$.

• Journal of Industrial Technology
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• v.37 no.1
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• pp.21-26
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• 2017

This work experimentally determined the effect of combining of microwave irradiation and the Fenton process on decolorization of methylene blue ($C_{16}H_{18}N_3SCl$, MB). As [$H_2O_2$] increased from 2.65 to 4.41 mM, the decolorization of MB increased from 22.7 to 99.1%. As [$Fe^{2+}$] increased from 0.07 to 0.18 mM, the decolorization of MB increased from 24.0 to 98.5%. MB removal efficiencies were ${\geq}95%$ at $[H_2O_2]{\geq}3.5mM$ and $3.5{\leq}[H_2O_2]/[Fe^{2+}]{\leq}17.3$, but $[H_2O_2]/[Fe^{2+}]{\geq}20$ caused a decrease in MB removal. A two-stage kinetic model matched the experimental data well.

• Journal of the Korean Ceramic Society
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• v.28 no.8
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• pp.593-602
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• 1991

Al2O3 and NiO-doped Al2O3 powders were prepared from the ethanol solution of Al (NO3)3$.$9H2O and Ni(NO3)2$.$6H2O by spray pylolysis method using two-fluid nozzle. As a result of spraying test with 0.3 mol/{{{{ iota }} concentration starting solution, mean droplet sizes varied with 8.99∼9.69$\mu\textrm{m}$ and those standard deviation were 4.57∼5.12. As-prepared powders which were synthesized at 1000$^{\circ}C$ have spherical shape, sizes of 0.1∼3.0$\mu\textrm{m}$ and specific surface area of 22.34∼24.20㎡/g. Most powders consisted of {{{{ gamma }}-Al2O3 phase and transforned into ${\alpha}$-A;2O3 phase by calcination at 1100$^{\circ}C$ for 1 hr. NiO-doped Al2O3 sintered bodies had better sinterability than those of pure Al2O3 and 0.3 wt% NiO-doped Al2O3 had near theoretical density and dense microstructure.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.118.2-118.2
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• 2011

In order to increase the energy conversion efficiency of dye-sensitized solar cells (DSSCs), we employed a counter electrode that was platinum coated using a doctor blade technique on synthesized ZnO nanostructures on fluorinedoped tin oxide (FTO). The ZnO nanostructures possessing high electrochemical activity and large surface area of the counter electrode were grown by a chemical bath deposition (CBD) method at various times, 2, 4, and 8 h. The efficiency of DSSC with the Pt-ZnO counter electrode was improved 7.01% (grown for 2 h), 7.63% (grown for 4 h), and 6.13% (grown for 8 h), respectively. Compared with a standard DSSC without ZnO nanostructures, whose efficiency was 6.27%, the energy conversion efficiency increased approximately 22% for the DSSC with the Pt-ZnO (grown for 4 h) electrode. It indicates that the Pt coated on the ZnO nanostructure improves the electrocatalytic activity of the counter electrode.

• Journal of the Korean Magnetics Society
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• v.3 no.1
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• pp.13-17
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• 1993

We have studied $CuF_{2}.2H_{2}O$ using $^{1}H$ and $^{19}F$ pulsed nuclear magnetic resonance at 30 MHz. From the data of lineshapes, the spin-lattice relaxation times ($T_1$) and the spin echo decay times, lattice dynamics in the structure is investigated. $T_1$ data from both $^{1}H$ and $^{19}F$ NMR indicate that spin-lattice relaxation is dominated by the paramagnetic ion centers at the Cu sites. The lineshapes at room temperature appear to be strongly affected by exchange narrowing and motional narrowing.

• Journal of the Korean Chemical Society
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• v.39 no.6
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• pp.434-439
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• 1995

Six-coordinate molybdenum(Ⅴ)-oxo complexes, (R4N)[MoO(NCS)2L](R=CH3, C2H5, n-C4, H9) with S-methyl-3-(2-hydroxy-x-phenyl)methylenedithiocarbazate(L1: x=5-H) and its derivatives (L2:x=5-CH3, L3: x=3-CH3O, L4: x=5,6-C4H4 and L5: x=5-NO2) have been synthesized and the structural, spectral and electrochemical properties of the complexes have been characterized by elemental analysis, molar conductivity, UV-Vis, IR, 1H NMR, and CV (cyclic voltammetry).

• Journal of Sensor Science and Technology
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• v.33 no.2
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• pp.105-111
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• 2024

In this study, the H₂S gas sensing characteristics were evaluated using surface-modified SnO₂ microparticles by tip sonication. The surface-modified SnO₂ microparticles were synthesized using the following sequential process. First, bare SnO₂ microparticles were synthesized via a hydrothermal method. Then, the surfaces of bare SnO₂ microparticles were modified with Ti nanoparticles during tip sonication. The sensing characteristics of SnO₂ microparticles modified with Ti were systematically investigated in the range of 100-300℃, compared with the bare SnO₂ microparticles. In this study, we discuss in detail the improved H₂S sensing characteristics of SnO₂ microparticles via Ti nanoparticle modification.