• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.407-419
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• 1996

Characteristics of visual air quality in Seoul have been investigated between June 13 and 21, 1994. Optical properties (extinction coefficient and particle scattering coefficient), meteorological parameters (relative humidity, temperature, wind speed, wind direction, and cloud cover), particle characteristics (mass size distribution, components) were measured and analyzed. During measurement periods, northwest wind with less than 2m/sec of wind speed deteriorates visibility. Effects of relative humidity are though to be not a direct factor which influence to visibility through the size change due to hygroscopic species in aerosol. During the smoggy period both the aerosol mass concentration and fine particle fraction of the size distribution are increased compared to the clear period. Sulfate, organic carbon, and elemental carbon in aerosol are the major species in determining the occurrence and severity of a smog in Seoul.

• Archives of Pharmacal Research
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• v.28 no.11
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• pp.1213-1218
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• 2005

N,N-Dialkylditihiocarbamate derivatives have been well known as broad-range fungicides. In this study, the triazole derivatives of ten new N,N-disubstituted dithiocarbamates (3a-j) were synthesized and their structures were identified by spectral and elemental analysis. Results of the antifungal activity studies showed that some of the compounds tested were active against M. canis, M. gypseum, and T rubrum at the concentration of 12.5 $\mu$g/mL when c1otrimazol was used as a standard.

• Carbon letters
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• v.5 no.2
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• pp.68-74
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• 2004

The polymer with contents of $C_{60}$ up to 57 wt.% was produced by mutual condensation of fullerene $C_{60}$ and ethylenediamine. The investigations of this polymer as well as pristine fullerene to comparison were carried out by FT-IR and UV-Vis spectroscopy, ToF-SIMS, TGA, and elemental analysis. At least three kinds of components was revealed as building blocks of polymer. The fullerene cage underwent only distortion but didn't destroy during formation of polymer. The pure fullerene was found as an intermediate of the thermal decomposition of polymer. The conclusion that this polymer could serve as precursor to produce carbon nanomaterial with high concentration curved graphene sheets and can be used for gas adsorption and electrochemical application was made.

• Journal of Environmental Science International
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• v.16 no.6
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• pp.689-698
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• 2007

Mesoporous silicas for heavy metals adsorption were prepared by co-condensation of surfactant as a template and Ludox HS-40 as a silica precursor. Various mesoporous silicas with the introduction of chelating ligands (mercaptopropyl and aminopropyl groups) were synthesized to remove heavy metal ions from aqueous solutions. The surface modification was conducted with a co-condensation process using the sequential or simultaneous addition of mesoporous silica and high concentration of the organosilane(3-mercaptopropyltrimethoxysilane and 3-aminopropyltriethoxysilane). These materials have been characterized by elemental analysis, XRD, SEM and TEM analysis. Adsorbents synthesized with 3-mercaptopropyltrimethoxysilane and 3-aminopropyltriethoxysilane shows a high loading capacity for Hg(II), Pb(II), Cd(II) and anion Cr(VI). Especially the one synthesized with a mercaptopropyl function has the highest adsorption capacity for Hg(II) and Cd(II).

• Textile Coloration and Finishing
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• v.32 no.3
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• pp.135-141
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• 2020

The primary and secondary alcohols in cellulose reacted with acrylonitrile(AN) in the presence of strong alkalis to form cyanoethylated cellulose. The partially cyanoethylated cotton(CEC) fabric with AN in the presence of aqueous sodium hydroxide solution was described, including effects of treatment time and reagent concentrations. The weight increases of cotton fabric were shown to be linearly related to the treatment time, temperature and concentration of sodium hydroxide. The physical properties such as shrinkage ratio and tensile strength were proportional to the weight increases without significant impact on elongation. But the moisture regain decreased with decreasing hydrophilicity. The degree of substitution(DS) and transfer ratio were linearly related to the weight increases. In the CEC with increasing weight up to 24.9%, it has been obtained with DS up to 0.63-0.67 cyanoethyl groups per anhydroglucose and transferring ratio up to 87.7%. The color fastness to washing by sublimation transfer printing was improved by the cyanoethylation.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.870-872
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• 2008

Barley $\beta$-glucan was subjected to chemical modification and the anticoagulant activity of the derivative was investigated. The barley $\beta$-glucan was successfully sulfated, showing the degree of substitution calculated by elemental analysis of 0.40. In addition, the Fourier transform infrared (FT-IR) spectra of the derivative confirmed the sulfation, which generated two new absorption bands at 1,250/cm (S=O) and 810/cm (C-O-S) compared to the native. Specially, the anticoagulant activity of barley $\beta$-glucan was created by sulfation, which increased in a concentration-dependent manner. This result demonstrated that the incorporation of sulfate groups into the $\beta$-glucan structure added a blood clotting prevention effect.

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.451-455
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• 1999

The polymerization of 2-ethynylpyridine by alkyl bromide carrying carbazole moiety, 6-(N-carbazolyl)hexyl bromide, relatively proceed well to give the corresponding poly[6'-(N-carbazolyl)hexyl-2-ethynylpyridinium bromide) in high yields under DMF reflux conditions without any initiator or catalyst. This polymerization was influenced upon the initial monomer concentration. The polymer yields and inherent viscosities of the resulting polymers were in the range of 34-85% and 0.11-0.21 dL/g, respectively. Instrumental analyses using NMR, IR, and UV-visible spectroscopies and elemental analysis indicated that the resulting polymer has a conjugated polymer backbone system carrying pyridine and n-hexyl carbazole moiety. The polymers were mostly brown powders and completely soluble in DMF, DMSO, nitrobenzene, and formic acid. The photoluminescence spectrum of the dilute polymer solution with the excitation at 383 nm exhibited two sharp peaks at 495 and 540 nm.

• Analytical Science and Technology
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• v.36 no.1
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• pp.1-11
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• 2023

A new, sensitive, and reliable flow injection methodology was investigated for the determination of lead ion (II) in vegetables' samples using a laboratory-prepared reagent 2-[(6-methoxy-2-benzothiazoly)azo]-4-methoxy phenol (6-MBTAMP). Infrared spectroscopy, UV-visible spectrophotometry, Energy dispersive X-ray spectroscopy (EDX), Elemental Analysis (CHN), nuclear magnetic resonance spectroscopy ¹HNMR, and ¹³CNMR techniques were used to characterize the reagent and lead (II) complex. The method is based on lead ion (II) reacting with the reagent (6-MBTAMP) in a neutral solution to produce a green-red complex with a maximum absorbance at 670 nm. The optimum conditions, such as flow rate, lead ion (II) volume, reagent volume, medium pH, reagent concentration, and reaction coil length were thoroughly examined. The limits of detection (LOD) and quantification (LOQ) were determined to be 0.621 mg·L^-1 and 2.069 mg·L^-1 , respectively, while Sandell's sensitivity was determined to be 0.345 ㎍·cm^-2.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.2
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• pp.169-179
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• 1998

This paper was performed to estimate interrelations between humus level of sediments and nutrient release from sediments in Dae-cheong reservoir. For investigations, sediments were sampled in June and October, in 1997 at fish farms, embayment, and the main stream of Dae-cheong reservoir. Items for investigation are as follows; water content, weight loss on ignition(IG), porosities of sediments, contents of element such as hydrogen, nitrogen, carbon, and nutrient release rates. Water contents and porosities were measured to conjecture the physical trait and grain size trait. Weight loss on ignition was measured to determine the contents of organic substance. For determination of the humus level of sediments, carbon and nitrogen contents were measured by elemental analyzer. As a result of elemental analysis, C/N ratio was determined in the range of $3.0\~13.1$. From the elemental analysis, humus level of Dae-cheong reservoir sediment was estimated from mesohumic state to oligotrophic state. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentrations of interstitial water and overlying water were measured. By using the concentration difference between interstitial water and overlying water and using the Fick's diffusion law, the release rates of phosphorus and nitrogen from the sediment samples were calculated. Release rates of nutrients which directly influence to the water quality were $0.05\~8.63mgP/m^2day$ and $4.99\~36.56mgP/m^2day$. It was found that release rate was measured higher in the 1st sampling period than in the 2nd sampling period. For the determination of phosphorus content in sediment, TPs were measured in 807\~1542{\mu}g/g$ in the 1st samling period and $677\~5238{\mu}g/g$ in the End samling period. Phosphorus release rate and phosphorus content were not interrelated each other.

• Journal of Environmental Science International
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• v.25 no.10
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• pp.1349-1368
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• 2016

Concentrations of fine particulate matter ($PM_{2.5}$) and several of its particle constituents measured outside homes in Houston, Texas, and Los Angeles, California, were characterized using multiple regression analysis with proximity to point and mobile sources and meteorological factors as the independent variables. $PM_{2.5}$ mass and the concentrations of organic carbon (OC), elemental carbon (EC), benzo-[a]-pyrene (BaP), perylene (Per), benzo-[g,h,i]-perylene (BghiP), and coronene (Cor) were examined. Negative associations of wind speed with concentrations demonstrated the effect of dilution by high wind speed. Atmospheric stability increase was associated with concentration increase. Petrochemical source proximity was included in the EC model in Houston. Area source proximity was not selected for any of the $PM_{2.5}$ constituents' regression models. When the median values of the meteorological factors were used and the proximity to sources varied, the air concentrations calculated using the models for the eleven $PM_{2.5}$ constituents outside the homes closest to influential highways were 1.5-15.8 fold higher than those outside homes furthest from the highway emission sources. When the median distance to the sources was used in the models, the concentrations of the $PM_{2.5}$ constituents varied 2 to 82 fold, as the meteorological conditions varied over the observed range. We found different relationships between the two urban areas, illustrating the unique nature of urban sources and suggesting that localized sources need to be evaluated carefully to understand their potential contributions to $PM_{2.5}$ mass and its particle constituents concentrations near residences, which influence baseline indoor air concentrations and personal exposures. The results of this study could assist in the appropriate design of monitoring networks for community-level sampling and help improve the accuracy of exposure models linking emission sources with estimated pollutant concentrations at the residential level.