• Archives of Pharmacal Research
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• v.19 no.3
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• pp.240-242
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• 1996

We have reported the convenient biomimetic methodology for the synthesis of all kinds of substituent pattern benzo[c]phenanthridine alkaloids (Hanaoka et al., 1990; Hanaoka et al., 1991). Regioselective demethylation of C-8 position on oxyfagaridine (5), an intermediate for the synthesis of Fagaridine (4), would afford the precursor for the synthesis of Isofagaridine because the strong hydrogen bonding between amide and hydroxyl group of C-7 position probably resists to be reacted with week base and electrophiles. Thus, a selective alkylation of dihydroxy compound supposed to be possible and be lead to the target compound, Isofagaridine.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.48-55
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• 2015

IMO to issue some restricted maritime legislation for reducing the adverse environmental impacts arising from such ship exhaust emissions. According to the IMO policy, every ship entering the Baltic SECAs has to equip the gas cleaning scrubber. The discharged waste solution by gas cleaning scrubber contains many types of salts, which to recover some valuable materials before disposal. This study try to achieve valuable salts including AN and AS throughout a few process such as selective organic solvents salting out, low temperature extraction and thermal evaporation. Amongst them, Thermal evaporation with repetition extraction using inorganic solvent was the most optimum to purify the extracted AN. This valuable salt was evaluated by Elemental analysis and Differential scanning calorimetry.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.3
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• pp.437-445
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• 2016

This paper discussed the effect of ammonia concentration adsorbed on fly ash for the ammonia emission as AAFA (Ammonia Adsorbed Fly Ash) produced from coal fired plants due to operation of NOx reduction technologies was landfilled with distilled or sea water at closed and open systems, respectively. Ammonia bisulfate and sulfates adsorbed on fly ash is highly water soluble. The pH of ammonium bisulfate and sulfate solution had significant effect on ammonia odor emission. The effect of temperature on ammonia odor emission from mixture was less than pH, the rate of ammonia emission increased with increased temperature when the pH conditions were kept at constant. Since AAFA increases the pH of solution substantially, $NH_3$ in the ash can release the ammonia order unless it is present at low concentration. $NH_4{^+}$ ion is unstable in fly ash and water mixtures of high pH at open system, which is changed to nitrite or nitrate and then released as ammonia gas. The proper conditions for < 20 ppm of ammonia concentration released from the AAFAs landfilled in ash pond were explored using an open system with sea water. It was therefore proposed that optimal operation to collect AAFA of less than 168 ppm ammonia at the electrostatic precipitator were controlled to ammonia slip with less than 5 ppm at SCR/SNCR installations, and, ammonia odor released from mixture of fly ash of 168 ppm ammonia with sea water under open system has about 20 ppm.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2303-2308
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• 2009

A thiocyanate poly(vinyl chloride) (PVC) membrane electrode based on [1,2-bis(diphenylphosphino)ethane]dihalopalladium( II), [(dppe)$PdX_2$, X = Cl ($L^1$), X = I ($L^2$)] as active sensor has been developed. The diiodopalladium complex, [(dppe)$PdI_2](L^2$) displays an anti-Hofmeister selectivity sequence: $SCN^-\;>\;I^-\;>\;{ClO_4}^-\;>\;Sal^-\;>\;Br^-\;>\;{NO_2}^-\;>\;{HPO_4}^-\;>\;AcO^-\;>\;{NO_3}^-\;>\;{H_2PO_4}^-\;>\;{CO_3}^{2-}$. The electrode exhibits a Nernstian response (-59.8 mV/decade) over a wide linear concentration range of thiocyanate ($(1.0\;{\times}\;10^{-1}\;to\;5.0\;{\times}\;10^{-6}$ M), low detection limit ($(1.1\;{\times}\;10^{-6}$ M), fast response $(t_{90%}$ = 24 s), and applicability over a wide pH range (3.5∼11). Addition of anionic sites, potassium tetrakis[p-chlorophenyl] borate (KTpClPB) is shown to improve potentiometric anion selectivity, suggesting that the palladium complex may operate as a partially charged carrier-type ionophore within the polymer membrane phase. The reaction mechanism is discussed with respect to UV-Vis and IR spectroscopy. Application of the electrode to the potentiometric titration of thiocyanate ion with silver nitrate is reported.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.3
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• pp.283-291
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• 1999

We have synthesized novel platinum (II) coordination complex containing cis-1,2-diaminocyclohexane (DACH) as a carrier ligand and 1,2-bis(diphenylphosphino)ethane (DPPE) as leaving group. Furthermore, nitrate was added to improve the water-solubility. A new series of [Pt(cis-DACH)(DPPE)] $2NO_3(PC)$ was evaluated its antitumor activity on various MKN-45 human gastric adenocarcinoma cell-lines and normal primary cultured kidney cells. The new platinum complex demonstrated high efficacy in the cytotoxicity on MKN-45 cell-lines as well as adriamycin-resistant (MKN-45/ADR) and cisplatin-resistant (MKN-45/CDDP) cells. The cytotoxicities of PC were found quite less than those of cisplatin in rabbit proximal renal tubular cells, human renal cortical cells and human renal cortical tissues using MTT assay, $[^3H]-thymidine$ uptake and glucose consumption tests. Based on these results, this novel platinum (II) coordination complex, was considered as better a valuable lead for improving antitumor activities with low nephrotoxicities in the development of a new clinically available anticancer chemotherapeutic agents.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1755-1762
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• 2013

A graphene-Zn/Al layered double hydroxide composite film was simultaneously prepared by electrochemical deposition on the surface of a glassy carbon electrode (G-LDH/GCE) from the mixture solution containing GO and nitrate salts of $Zn^{2+}$ and $Al^{3+}$. The modified electrode showed good electrochemical performances toward the simultaneous electrochemical detection of hydroquinone (HQ), catechol (CA) and resorcinol (RE) due to the unique properties of graphene (G) and LDH such as large active surface area, facile electronic transport and high electrocatalytic activity. The redox characteristics of G-LDH/GCE were investigated with cyclic voltammetry and differential pulse voltammetry. The well-separated oxidation peak potentials, corresponding to the oxidation of HQ, CA and RE, were observed at 0.126 V, 0.228 V and 0.620 V respectively. The amperometric response of the modified electrode exhibited that HQ can be detected without interference of CA and RE. Under the optimized conditions, the oxidation peak current of HQ is linear with the concentration of HQ from 6.0 ${\mu}M$ to 325.0 ${\mu}M$ with the detection limit of 0.077 ${\mu}M$ (S/N=3). The modified electrode was successfully applied to the direct determination of HQ in a local tap water, showing reliable recovery data.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.86-94
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• 1984

The single crystal ion-selective electrode,$ {\beta}-Ag_3SI/PVC-THF $membrane electrode has showed a linear potential response to the activities of iodide ion (10-1${\sim}$10-7M). The $ {\beta}-Ag_3SI$ membrane electrode was compared with AgI/PVC-THF membrane and copper metal plate membrane electrodes. In order to measure the selectivity coefficient of the electrodes toward $Cl^-$ and $Br^-$, the separation and mixed solution method were employed. The potential-time curve was obtained by the usual immersion technique and pH effect was also examined. The orders of selectivity for $Br^-$, $Cl^-$ and stability of response time are ${\beta}-Ag_3SI/PVC-THF $membrane > AgI/PVC-THF membrane > copper metal plate membrane. These electrodes could be used as indicating electrodes in the potentiometric titration of a single halide and mixed halides with the standard solution of silver nitrate.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.451-455
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• 2012

Dense Cr-precursor nano-hexaprisms were prepared by heating the Cr-nitrate aqueous solution containing Hexamethylenetetramine and polyvinylpyrrolidone, which were converted into porous $Cr_2O_3$ nano-hexaprisms containing nanoparticles by heat treatment of Cr-precursors at $600^{\circ}C$ for 2 h in air atmosphere. At the sensor temperature of $300^{\circ}C$, porous $Cr_2O_3$ nano-hexaprism showed the high response ($R_g/R_a$, $R_g$: resistance in gas, $R_a$: resistance in air) to 100 ppm $C_2H_5OH$ ($R_g/R_a=69.8$) with negligible cross-responses to 100 ppm CO and 5 ppm $C_6H_6$. The sensitive and selective detection of $C_2H_5OH$ in porous $Cr_2O_3$ nano-hexaprism were discussed in relation to the morphology of nanostructures.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.303-307
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• 2017

Pure $In_2O_3$, 0.5 and 1.0 wt% Mg doped $In_2O_3$ hollow spheres were synthesized by ultrasonic spray pyrolysis of a solution containing In-, Mg-nitrate and sucrose and their gas sensing characteristics to 5 ppm $C_2H_5OH$, p-xylene, toluene, and HCHO were measured at 250, 300 and $350^{\circ}C$. Although the addition of Mg decreases the specific surface area and the volume of meso-pores, the gas response (resistance ratio) of the 0.5 wt% Mg doped $In_2O_3$ hollow spheres to 5 ppm $C_2H_5OH$ at $350^{\circ}C$ (69.4) was significantly higher than that of the pure $In_2O_3$ hollow spheres (24.4). In addition, the Mg doped $In_2O_3$ hollow spheres showed the highest selectivity to $C_2H_5OH$. This was attributed to the dehydrogenation of $C_2H_5OH$ assisted by basic MgO into reactive $CH_3CHO$ and $H_2$.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.281-284
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• 2005

The Fe/MgO catalysts with different Fe loadings (1, 4, 6, 15 and 30 wt% Fe) were prepared by a wet impregnation with iron nitrate as precursor. All of the catalysts were characterized by BET surface analyzer, X-ray diffraction (XRD), temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The maximum removal capacity of $H_2S$ was obtained with 15 wt% Fe/MgO catalyst which had the highest BET surface area among the measured catalysts. XRD of Fe/MgO catalysts showed that well dispersed Fe particles could be present on Fe/MgO with Fe loadings below 15 wt%. The crystallites of bulk $\alpha$-$Fe_2O_3$ became evident on 30 wt% Fe/MgO, which were confirmed by XRD. TPR profiles showed that the reducibility of Fe/MgO was strongly related to the loaded amounts of Fe on MgO support. Therefore, the highest removal efficiency of $H_2S$ in wet oxidation could be ascribed to a good dispersion and high reducibility of Fe/MgO catalyst. XPS studies indicated that the $H_2S$ oxidation with Fe/MgO could proceed via the redox mechanism ($Fe^{3+}\;{\leftrightarrow}\;Fe^{2+}$).