• Journal of Environmental Science International
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• v.7 no.2
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• pp.203-208
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• 1998

A simple on-line measurement system consisting of a conventional peristaltic pump, a HPLC-type heater, and a flow-through spectrophotometer is introduced for the determination of chemical oxygen demand(CODI. The system was configured such that the reaction mixture in the highly concentrated surffuric acrid medium flowing through the PTFE reaction tubing was heated at 150℃ and the absorbance of dichromate was continuously moutored at 445 m. The same addation principle as in the standard procedure was employed akcept the use of CoSO4 as a new effective catalyst. To test the system, potassium hydrogen phthalate was selected as a COD standard material. With suitably optimized reaction condition, the applicable concentration range depends on the concentration of potassium dichromate in the oxidizing reagent. With 2.0×10-3 M and 5.0×10-4M dichromate, the linear dynamic range was observed up to 400 ppm and 100 ppm, respectively. The standards in the Unear ranges were shown to be completely oxidized, which was confirmed with sodium oxalate or Mohr's salt. In all cases, the typical reproduclbility for betweenruns was 2% or less. The proposed measurement system provides the valuable in- formation for the further development of automated analysis system based on the present standard procedure.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.669-677
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• 2002

This study was conducted to investigate the characteristics of role of transport on aerosol concentration at Crate Lake, Oregon USA for 1988.3~1999. 5. The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of representatives from USA federal and regional-state organizations. Also IMPROVE sampler is designed to obtain a complete signature of the composition of the airborne particles affecting visibility. According to 10-day backward isentropic trajectory analysis, the frequency of local, marine and Asian trajectory showed 33.1%(335 cases), 47%(478 cases), 5.2%(53 cases) respectively. The monthly variation of nss $SO_4^{2-}$, nss S, $NO_3^-$, K and C showed the double peak pattern, high in April~May and August~september and showed the lowest concentration in Winter. The other constituents concentration except for Cl$^{[-10]}$ , Na, Mg was high in local trajectory than marine trajectory. A ratio nss $SO_4^{2-}$ to $SO_4^{2-}$ was 90.5% in marine trajectory and 98% in local trajectory. It suggest that the aerosol in Crater Lake was effected by salt. The annual mean concentration of nss $SO_4^{2-}$ and nss S decreased but the springtime concentration increased.

• Journal of the Korean Ceramic Society
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• v.45 no.4
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• pp.196-203
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• 2008

Metal-carbon/$TiO_2$ composite photocatalysts were thermally synthesized through the mixing of anatase to metal(Cu, Zn) containing phenol resin in an ethanol solvent coagulation method. The BET surface area increases, with the increase depending on the amount of metal salt used. From SEM images, metal components and carbon derived from phenol resin that contains metal was homogeneously distributed to composite particles with porosity. XRD patterns revealed that metal and titanium dioxide phase can be identified for metal-carbon/$TiO_2$ composites, however, the diffraction peaks of carbon were not observed due to the low carbon content on the $TiO_2$ surfaces and due to the low crystallinity of the amorphous carbon. The results of a chemical elemental analysis of the metal-carbon/$TiO_2$ composites showed that most of the spectra for these samples gave stronger peaks for C, O, treated metal components and Ti metal compared to that of any other elements. According to photocatalytic results, the MB degradation can be attributed to the three types of synergetic effect: photocatalysis, adsorptivity and electron transfer, according to the light absorption between the supporter $TiO_2$, metal species, and carbon layers.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.53-63
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• 2004

Planting models for restoration forest on the seaside have been demanded because coastal reclaimed land has increased for habitation sites, industrial complexes and new towns on the west seaside of Korea. The planting models have to consider endurance for bad environmental conditions in order to make a role to protect the urban space against the extreme seaside environment. The dominant species, relative impotance value, individuals and species number were analysed in natural forests that were exposed to extreme seaside conditions in Deokjeok island and Younghung island, Incheon. The native species such as Pinus thunbergii and Pinus densiflora, which survive on the seaside, were mainly recommended because the coastal reclaimed land had extreme environmental conditions. Stable vegetation structures could be made by multi-layer planing by using these species. A diverse vegetation community could be made according to these planting models. The maritime forests made by these planting models might be more effective for environmental adaptation and a windbreak forest than alone tree, and the young trees below 3m height could easily adapt to these conditions.

• Journal of Surface Science and Engineering
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• v.29 no.5
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• pp.563-569
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• 1996

Degradation of $Zn_3N_2$ films is studied by using several analytical techniques. Polycrystalline $Zn_3N_2$ films prepared by reactie rf magnetron sputtering are kept in the air. Electrical and optical properties are measured by using van der Pauw technique and double-beam spectrometry. Structure and chemical bonding states are studied by X-ray diffraction(XRD), Fourier transfer infrared ray spectroscopy(FT-IR) and X-ray photoelectron specroscopy (XPS). Significant differences are observed in optical properties between the degraded film and the ZnO film. XRD analysis reveals that the degraded film contains very small ZnO grains because very weak and broad ZnO peaks are observed. XPS and FT-IR measurements reveal the formation of $Zn(OH)_2$ in the degraded film. The existence of N-H bonds in degraded films is exhibited from the N 1s spectra. $Zn_3N_2$ change into the mixture of ZnO, $Zn(OH)_2$ and an ammonium salt.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.201-211
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• 2011

Many reinforced concrete structures have been constructed at the offshore in Korea and those are exposed in environments for long period. Due to that, the reinforcement of the structure faces possibility of corrosion by the salt damage. Such corrosions are effects on the bond performance between concrete and reinforcing bar as well as the performance of the structure. In this study, the performance of RC structure has been investigated when the reinforcing bars are totally bonded and unbonded in the structure. Through the experimental tests and finite element analyses of beam-column joint with bond and unbonded reinforcing bar, the energy dissipation capacity, strength, and crack distribution are compared and discussed.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.489-490
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• 2006

Branched sulfonated poly(ether sulfone-ketone) copolymer was prepared with bisphenol A, 4,4-difluorobenzophenone, sulfonated chlorophenyl sulfone (40mole% of bisphenol A) and THPE (1,1,1-tris-p-hydroxyphenylethane). THPE was used 0.4 mol% of bisphenol A to synthesize branched copolymers. Organic-inorganic nano composite membranes were prepared with copolymer and a series of $SiO_2$ nanoparticles (20 nm, 4, 7 and 10 wt%). The composite membranes were cast from dimethylsulfoxide solutions. The films were converted from the salt to acid forms with dilute hydrochloric acid. The membranes were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol. Branched copolymer and nano composite membranes exhibit proton conductivities from $1.12{\times}10^{-3}$ to $6.04{\times}10^{-3}\;S/cm^2$, water uptake from 52.9 to 62.4%, IEC from 0.81 to 1.21 meq/g and methanol diffusion coefficients from $1.2{\times}10^{-7}$ to $1.5{\times}10^{-7}\;cm^2/S$.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1432-1440
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• 2012

Weissella confusa 31, an isolate from human feces, possesses desirable properties as a probiotic strain, including bile salt resistance. W. confusa 31 is not inhibited by bile salts up to 0.3% concentration. Proteins affected by bile salts (0.05%) were examined by 2-D gel electrophoresis. Our proteomic analyses revealed that the intensities of 29 spots were changed, where 17 increased (including 2 spots observed only under the bile salts stress conditions) and 12 decreased. Proteins were identified by MALDI-TOF mass spectrometry. Proteins increased in the band intensities included adenylate kinase (12.75-fold increase), Clp-like ATP-dependent protease (11.91-fold), 6-phosphogluconate dehydrogenase (10.35-fold), and HSP 70 (5.07-fold). Some of the increased or decreased proteins are also known to be involved in other types of stress responses.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.253-261
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• 1999

It is essential for port planning, coastal zone management and environmental impact study to analyze the variation of current and water quality due to the development of water area and discharged water from the estuary barrage and basin, etc. Mokpo sea area has downstream from a long river and two large basins, the Yongsan river and Yongam-Kumho basins, discharging much of water through water gates for the purpose of flood and prohibition of salt intrusion to the inland fresh water area. In this study, the numerical calculation were carried out for the analysis of diffusion characteristics due to discharging operation, adopting the results of tidal current simulation. ADI method is applied to the governing equation for the movement of sea water and diffusion and 6-point method to the advection terms of diffusion equation. As the results of this study, it is known that the discharging operation causes increasing and/or decreasing of current velocity and enlarging and/or depressing of pollutant diffusion limits depending on the distance from the discharging gates and the modes of discharging operation. To utilize these result, the linked gate operation and the method increasing exchange of sea water must be considered.

• Macromolecular Research
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• v.16 no.2
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• pp.169-177
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• 2008

This paper reports a facile synthesis of new water-soluble poly(ethylene oxide) (PEO)-based amphiphilic block copolymers showing pH sensitive phase transition behaviors. The copolymers were prepared by atom transfer radical polymerization (ATRP) of methacrylamide type of monomers carrying a sulfonamide group using a PEO-based macroinitiator and a Cu(I)Br/$Me_6TREN$ catalytic system in aqueous media. The resulting polymers were characterized by a combination of $^1H$-NMR, size exclusion chromatography, and UV/Visible spectrophotometeric analysis. The micellization of the block copolymers as a drug-loading mechanism in aqueous media using fluorescein salt was examined as a function of pH. The stable micelle formation and its loading efficacy suggest that the block copolymers can be used as precursors for drug-nanocontainers.