• Polymer(Korea)
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• v.36 no.4
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• pp.531-535
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• 2012

Conductive polyaniline (PANI) nanofibers in UV-curable resin were used for a transparent conductive film. The emeraldine-salt PANI (ES-PANI) nanofibers were prepared by chemical oxidation polymerization of aniline, which could be changed into emeraldine-base PANI by dedoping. EB-PANI nanofibers as a precursor for conductive fillers were thereby transformed into re-dpoed PANI (rES-PANI) by dodecylbenzenesulfonic acid in the UV-curable resin solution. rES-PANI nanofibers have high conductivity and long-term stability in the solution without a defect of nanostructure. The resulting conductive resin solution was proved to be highly stable where no precipitation of rES-PANI fillers was observed over a period of 3 months. The transparent film was spin-casted on a poly(methyl methacrylate) sheet of thickness ca. $5{\mu}m$. A surface resistance of $6.5{\times}10^8{\Omega}/sq$ and transmittance at 550 nm of 91.1% were obtained for the film prepared with a concentration of 1.4 wt% rES-PANI nanofibers in the solution. This transformation process of rES-PANI from ES-PANI by dedoping-redoping can be an alternative method for the preparation of an antistatic protection film with controllable surface resistance and optical transparencies with the PANI concentration in UV-curable solution.

• Journal of the Korean Electrochemical Society
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• v.5 no.1
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• pp.21-26
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• 2002

A supercapacitor was developed using an amorphous ruthenium oxide material. The electrode of supercapacitor was prepared using an amorphous ruthenium oxide, which was synthesized from ruthenium trichloide hydrate$(RuCl_3{\cdo5}xH_2O)$. Thin film of tantalum was used as a current collector because it had wide. potential window characteristics than titanium and 575304 materials. A supercapacitor was assembled with ruthenium oxide as an electrode active material and 4.8M sulfuric acid solution as an electrolyte. The specific capacitance of the electrode was tested by a cyclic voltammetry using a half cell. The maximum differential specific capacitances during the oxidative and the reductive scans were 710 and $645\;F/g-RuO_2{\cdot}nH_2O$, respectively. The average specific capacitance was $521\;F/g-RuO_2{\cdot}nH_2O$. The assembled supercapacitor was protonated to the potential level of 0.5V vs. SCE. Super-capacitor, which was adjusted to the appropriate protonation level, had the specific capacitance of $151\;F/g-RuO_2{\cdot}nH_2O$ based on the concept of full cell.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.569-581
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• 1990

It is generated in DMF by activated catalysts of superoxo cobalt(III) complex, such as [Co(III)(Schiff base)(L)]O$_2$ (Schiff base; SED, SOPD and o-BSDT, L; DMF and Py) which mole ratio of oxygen to metal is 1:1 that oxidation major product of 2,6-di-tert-butylphenol by homogeneous oxidatve catalysts of oxygen adducted tetradentate Schiff base cobalt(III) is 2,6-ditert-butylbenzoquinone (BQ). And oxidation product of 3,3',5,5'-tetra-tert-butyldiphenoquinone (DPQ) is generated by activated catalysts such as $\mu$-peroxo cobalt(III) complex; $[Co(III)(SND)(L)]_2$$O_2$ (L; DMF and Py) which mole ratio of oxygen to metal is 1:2. It is difficult to identify these homogeneous activated catalysts such as superoxo and $\mu$-peroxo cobalt(III) complexes in DMF and DMSO solvents. But we can identify by P.V.T method of the oxygen absorption in pyridine solvent and by the reduction process occurred to four steps including prewave of O$_2$- in 1:1 oxygen adducted superoxo cobalt(III) complexes and three steps not including prewave of O$_2$- in 1:2 oxygen adducted $\mu$-peroxo cobalt(III) complexes by the cyclic voltammetry with glassy carbon electrode in 0.1 M TEAP as supporting electrolyte solutidn.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.86-91
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• 2008

Dicamba(3,6-dichloro-2-methoxybenzoic acid) is used to control for pre and post-emergence of annual and perennial broad-leaf weeds. It is very soluble in water and highly mobile, acidic herbicide. So it is easily moved and detected in groundwater. Zerovalent iron(ZVI) has been used for the reductive degradation of certain compounds through amination of nitro-substituted compounds and dechlorination of chloro-substituted compounds. In this study, we investigated the potential of ZVI for the oxidative degradation of dicamba in water. The degradation rate of dicamba by ZVI was more rapidly increased in pH 3.0 than pH 5.0 solution. The degradation percentage of dicamba was increased with increasing amount of ZVI from 0.05% to 1.0%(w/v) and reached above 90% within 3 hours of reaction. As a result of identification by GC-MS after derivatization with diazomethane, we obtained three degradation products of dicamba by ZVI. They were identified 4-hydroxy dicamba or 5-hydroxy dicamba, 4,5-dihydroxy dicamba and 3,6-dichloro-2-methoxyphenol. 4-Hydroxy dicamba or 5-hydroxy dicamba and 4,5-dihydroxy dicamba are hydroxylation products of dicamba. 3,6-dichloro-2-methoxyphenol is hydroxyl group substituted compound instead of carboxyl group in dicamba. We also confirmed the same degradation products of dicamba in the Fenton reaction which is one of oxidation processes using ferric sulfate and hydrogen peroxide. But we could not find out the dechlorinated degradation products of dicamba by ZVI.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.639-647
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• 1998

Al-containing titanium silicalite-1 ([Al]-TS-1) catalyst was prepared hydrothermally, and the effects of synthesis parameters such as silica/alumina sources, $SiO_2/TiO_2$ ratio, and aging treatment were investigated. The structure, crystal size, and shape were examined by XRD and SEM, and the extent of titanium incorporation into the zeolite framework was examined using UV-vis DRS spectroscopy. For [Al]-TS-1 catalyst preparation, aging of ca. 24h was essential, and the faster crystallization rates were achieved with Cab-O-Sil than with Ludox or TEOS as a silica source. In addition, the higher crystallinity and faster crystallization rate were obtained using sodium aluminate as an aluminum source. 2-butanol oxidation using $H_2O_2$ as an oxidant was carried out to confirm the redox property of the [Al]-TS-1. Acid sites catalyzed toluene alkylation study indicated that lattice titanium species in [Al]-TS-1 weakened the acid strength, and the para-ethyltoluene selectivity was enhanced as a results.

• Economic and Environmental Geology
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• v.34 no.4
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• pp.329-343
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• 2001

The deep environment and geochemical evolution of the Bugok geothennal waters, located in the Kyeongnam Province, was re-interpreted based on the hydrochemical and isotopic data published by Yun et al. (1998). The geothermal waters of the Bugok area is geochemically divided into three groups; Geothennal water I, II and III groups. Groups I and II are geochemically similar; high temperature (55.2-77.2$^{\circ}$C) and chemically belonging to Na-S04 types. However, pH and Eh values are a little different each other and Group II water is highly enriched in S04 compared to Group I water. Group III water, occurring from peripheral sites of the central part of the geothennal waters, shows temperature range of 29.3 to 47.0$^{\circ}$C and belongs to $Na-HCO_3-S0_4$ types. The deep environment and geochemical evolution of the Bugok geothennal waters, showing the diversity of geochemistry, can be interpreted as follows; I) Descending to great depth of meteoric waters that originated at high elevation and reacting with sediments and/or granites in depth. The $S0_4$ concentration of the waters has been increased by the dissolution of sulfate minerals in sediments. 2) During the continuous descending, the waters has met with the reduction environment, producing the $H_2S$ gas due to sulfate reduction. The waters has been heated up to 130$^{\circ}$C and the extent of water-rock reaction was increased. At this point, pH of waters are increased, S04 concentration decreased and calcite precipitated, therefore, the waters show the $Na-S0_4$ type. 3) Ascending of the geothennal waters along the flow path of fluids and mixing with less-deeply circulated waters. The $S0_4$ concentration is re-increased due to the oxidation of $H_2S$ gas and/or sulfide minerals in sediments. During continuous ascending, these geothennal waters are mixed with shallow groundwater.

• Food Science of Animal Resources
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• v.26 no.1
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• pp.1-8
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• 2006

To investigate the effect of ${\beta}$-hydroxyacyl CoA-dehydrogenase(HADH) activity increased by freezed and thaw process on myoglobin(Mb) oxidation without lipid oxidation during, pork loins were collected at postmortem 24 hts and sliced to steaks (3 cm thickness). Samples were packaged in a polyethylene bag and subjected to flesh group (control), one cycle fieezed and thaw group (treatment 1) and two cycles freezed and thaw group (treatment 2), respectively. Samples were measure meat color (CIE $L^*,\;a^*,\;b^*$), the contents(%) of MetMb, thiobarbituric acid reactive substance (TBARS) value and HADH(${\beta}$-hydroxyacyl CoA-dehydrogenase) activity at 0, 3, and 7 days of storage at $4^{\circ}C$. Both treatments showed significantly (p<0.05) lower $L^*$ and higher $L^*$ value compared to those of control at 7 days. On the contrary, MetMb contents(%) of treatments were significantly (p<0.05) higher than those of control during cold storage. However there were no significant (p> 0.05) differences in TBARS values between control and treatments during 7 days. There were significant (p<0.05) differences in HADH activity between control and treatments at 3 days of cold storage. Both treatments showed higher HADH activity compared to those of control. These results suggested that the freezed and thaw process could accelerate meat color deterioration, i.e. increased MetMb percentage without lipid oxidation in pork loin during cold storage. This also implied that autoxidation of Mb in freezed and thaw pork loin was influenced by enzyme-catalysed reactions in the tissue that would lead to decreased OxyMb.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1248-1256
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• 2014

The purpose of this study was to investigate the mechanisms of behind $SO_2$ formation and elevated cause of reducing power in purple bamboo salt (PBS) along with an analysis of physicochemical properties, content of sulfur compounds, oxidation reduction potential (ORP), mineral contents of salt type (MSS, mudflat solar salt; BS, bamboo salt), and addition of raw bamboo (RB). $SO_2$ content of 630 ppm was detected in PBS. $SO_2$ was not detected in MSS, BS, or RB, whereas $SO_2$ (782 ppm) from $K_2SO_4$ was detected after heating a NaCl, KCl, $MgCl_2$, $MgSO_4$, MgO, $CaCl_2$, $K_2SO_4$, and $FeSO_4$ with RB. $SO_2$ content of BS increased with baking time, and it originated from BSRB1 (13.88 ppm) to BSRB4 (109.13 ppm). $SO_3{^{2-}}$ originated only from MSSRB4 and BSRB2~BSRB4. Sulfate ion content decreased along with increasing $SO_2$ and sulfite ion contents. ORP increased with baking time of MSS and BS, and it was present at higher levels in BSRB4 (-211.40 mV) of BS than MSS. Insoluble content was higher in BS than MSS. Further, Ca, K, and Mg ion contents decreased in MSS and increased in BS with baking time. BSRB4 had 1.4 fold higher levels of Ca, 1.5 fold higher levels of Mg, and 1.8 fold higher levels of K than BS. Li, Al, Mn, Fe, and Sr in MSS as well as Al, Fe, and Ni in BS increased with baking time. Anions (Cl, $NO_3$, and Br) and heavy metals (Pb, Cd, Hg, and As) between MSS and BS were not significantly different. These results suggest that the reducing power of BS was due to $SO_2$ and sulfite ion. To increase the amounts of these compounds and reducing power, higher melting temperature and longer baking time are necessary along with BS, which is created by the addition of RB to roasted salt.

• Journal of the Korean Electrochemical Society
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• v.14 no.4
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• pp.214-218
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• 2011

The electrochemical characteristics and performance of redox flow battery using the soluble lead has been evaluated. Cyclic voltammetry was performed on the materials to evaluate deposition and dissolution of lead and lead dioxide. In the negative region, a reduction peak is not observed, and on the reverse scan, on-set voltage is observed at -0.47 V(vs SCE). In the positive region, the distinct peak is observed on the forward and reverse scan. The charge/discharge experiments were carried out graphite electrode in the beaker cell. The charging(deposition) of lead occurs at around 0.5 V(vs SCE) and discharging(dissolution) of lead occur at around 0.25 V(vs SCE). The potential difference is about 0.25 V. The charging(deposition) of dioxide lead is at 1.77 V(vs SCE) and discharging(dissolution) is at around 0.95 V(vs SCE) during first cycle. On subsequent cycles, the charging of dioxide lead starts at below 1.5 V(vs SCE), after a period the voltage increase to 1.7 V(vs SCE). The voltage of discharging is stable at around 1.0 V(vs SCE).

• Journal of the Korean Chemical Society
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• v.44 no.4
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• pp.363-375
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• 2000

In this study, the changes of contents and formats of science textbooks of North Korean sec-oery much and the quality of papers in the textbooks became worse. The changes of ratios of contents were as follows. While the ratio of 'Chemical Change' was increased especially in the contents of 'Acids and Bases' and 'Oxidation and Reduction', the ratios of'EIements and Compounds' and 'Structure of theMaterials' were decreased. The ratio or 'Science-Technology-Society' which hasbeen stressed very much recently in the science education was low in the eighties, and the ratio is even lower in the nincties. 0n the basis of these facts,it can be concluded that the world-wide recent trends in science education hardly affected North Korean science education.