• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.191-195
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• 2021

Pure ZnFe₂O₄ and Fe₂O₃-ZnFe₂O₄ hetero-composite spheres were prepared by ultrasonic spray pyrolysis of a solution containing Zn- and Fe-nitrates. Additionally, the sensing characteristics of these spheres in the presence of 5 ppm ethanol, benzene, p-xylene, toluene, and CO (within the temperature range of 275-350 ℃) were investigated. The Fe₂O₃-ZnFe₂O₄ hetero-composite sensor with a cation ratio of [Zn]:[Fe]=1:3 exhibited a high response (resistance ratio = 140.2) and selectivity (response to p-xylene/response to ethanol = 3.4) to 5 ppm p-xylene at 300 ℃, whereas the pure ZnFe₂O₄ sensor showed a comparatively lower gas response and selectivity. The reasons for the superior response and selectivity to p-xylene in Fe₂O₃-ZnFe₂O₄ hetero-composite sensor were discussed in relation to the electronic sensitization due to charge transfer at Fe₂O₃-ZnFe₂O₄ interface and Fe₂O₃-induced catalytic promotion of gas sensing reaction. The sensor can be used to monitor harmful volatile organic compounds and indoor air pollutants.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.87-98
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• 2016

During the period between July 3 and 27 of 2009, water samples were collected from the Russian coast at a depth of 30m from 26 stations (including Ulleung and Japan basins) onboard the Russian survey vessel R/V Lavrentyev following 4 lines (D, R, E, and A). The samples were analyzed for nutrients and chlorophyll a contents. All parameters exhibited higher values in warm waters than in cold waters ($NH_4:1.8-fold$, $PO_4:1.8-fold$, $SiO_2:1.2-fold$, and chlorophyll-${\alpha}$:1.9-fold), except nitrates, which was 1.4-fold higher in cold waters than in warm waters. The horizontal distribution of ammonia, phosphate, and chlorophyll-${\alpha}$ was very similar to each other and showed the highest values in the waters near Russia, where a upwelling influence of cold current and bottom water prevails, while relatively low distribution was observed at the Ulleung Basin. On the other hand, nitrates showed the highest concentration at the Ulleung Basin, which is under the direct influence of the Tsushima warm water, and showed a gradual decrease northward. The N/P ratio showed the highest value in the Tsushima middle water, rather than in the North Korean Cold Water, the Tsushima Warm Water was the primary source of nitrate flow into the East Sea. However, the average concentration of phosphate in the warm waters was < $0.2{\mu}M$, thereby limiting phytoplankton growth, while a high concentration of phosphate in cold waters showed a direct correlation with chlorophyll-${\alpha}$. The results of principal component analysis for the identification of primary factors that influence the marine environment showed that principal component I was water temperature and principal component II was influenced chlorophyll-${\alpha}$ and nutrients. Therefore, Study area has greatest influenced by water temperature, and clearly distinct cold and warm water regions were observed in the East Sea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.153-159
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• 1997

Pokeweed, a polycarpic plant, has been used as herbage medicine, vegetable or dye. It, however, is known as an aggressive plant in the vicinity of the industrial area evolving air pollutants. The experiment was done to determine the effect of priming using nitrates, germination temperature and light quality on germination of its seed to get information on the optimum germination process as well as its establishment. The daily percent germination was measured to 12 days after sowing since its seeds were treated by two different nitrates [KNO$_3$, Ca(NO$_3$)$_2$]. their different concentrations (0, 50, 150, 300mM), then treatment duration (1, 3, 6 days), different germination temperature (day /night; 30/30, 30/20, 20/30, 20/2$0^{\circ}C$) and light quality (red, white, dark) before or during germination. The percent germination was greater in the KNO$_3$ treatment than in the Ca(NO$_3$)$_2$ but in the priming treatment with KNO$_3$ in comparison with no-priming. In the priming treatment with KNO$_3$, the percent germination was increased with its increased concentration to 150mM although decreased with delayed duration to 6 days. Regardless of light quality, the greater percent germination was shown in the order of 2$0^{\circ}C$ constant and 20/3$0^{\circ}C$ alternative, 3$0^{\circ}C$ constant, 30/2$0^{\circ}C$ alternative temperature. The germination was less in the dark during germination than in the illumination in which the red light had greater percent germination compared to white light. The seeds primed with KNO$_3$ were germinated under the alternative temperature even in the dark condition.

• Asian Journal of Atmospheric Environment
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• v.6 no.2
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• pp.83-95
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• 2012

China has been a top producer and exporter of refined lead products in the world since the year 2000. After the phasing-out of leaded gasoline in the late 1990s, non-ferrous metallurgy and coal combustion have been identified as potential major sources of aerosol lead in China. This paper presents the single particle analytical results of ambient aerosol particles collected near a lead smelter using a scanning electron microscopy- energy dispersive x-ray spectroscopy (SEM-EDX). Aerosol particle samples were collected over a 24-hour period, starting from 8 pm on 31 May 2002, using a high volume TSP sampler. For this near source sample, 73 particles among 377 particles analyzed (accounting for 19.4%) were lead-containing particles mixed with other species (S, Cl, K, Ca, and/or C), which probably appeared to be from a nearby lead smelter. Lead-containing particles of less than $2{\mu}m$ size in the near source sample were most frequently encountered with the relative abundances of 42%. SEM-EDX analysis of individual standard particles, such as PbO, PbS, $PbSO_4$, $PbCl_2$, and $PbCO_3$, was also performed to assist in the clear identification of lead-containing aerosol particles. Lead-containing particles were frequently associated with arsenic and zinc, indicating that the smelter had emitted those species during the non-ferrous metallurgical process. The frequently encountered particles following the lead-containing particles were mineral dust particles, such as aluminosilicates (denoted as AlSi), $SiO_2$, and $CaCO_3$. Nitrate- and sulfate-containing particles were encountered frequently in $2-4{\mu}m$ size range, and existed mostly in the forms of $Ca(NO_3,SO_4)/C$, $(Mg,Ca)SO_4/C$, and $AlSi+(NO_3,SO_4)$. Particles containing metals (e.g., Fe, Cu, and As) in this near source sample had relative abundances of approximately 10%. Although the airborne particles collected near the lead smelter contained elevated levels of lead, other types of particles, such as $CaCO_3$-containing, carbonaceous, metal-containing, nitrates, sulfates, and fly-ash particles, showed the unique signatures of samples influenced by emissions from the lead smelter.

• Analytical Science and Technology
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• v.33 no.3
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• pp.143-150
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• 2020

In this study, crude protein was analyzed and compared using the Kjeldahl and Dumas method for cereals, meat, sea food, chemical samples and vegetable. The nine kinds of cereal, including white rice, were analyzed. In the result, the correlation coefficient of the Kjeldahl and the Dumas method indicated that there was no significant difference between them, showing 0.994 of it and 0.956 of p-value. Also, for the nine kinds of meat, five kinds of sea food, three kinds of chemical samples, four kinds of vegetable, there was little difference about the correlation coefficient of the Kjeldahl and the Dumas method, showing 0.9725, 0.9879, 0.9985 and 0.9873 of it and 0.947, 0.761, 0.997 and 0.727 of p-value, respectively. For the samples of meat, they were not fully homogenized, so the reproducibility of them was not good in the Dumas method, which is required to be analyzed in small size. However, when vegetables, which contain a lot of nitrates, are analyzed using Kjeldahl, they showed the lower reproducibility compared to the result of using Dumas because they are not completely decomposed in the Kjeldahl method. In the Dumas method, the samples should be homogenized because only 0.1 g sample is used. In short, neither of the Kjeldahl and Dumas methods are an accurate quantitative test because both of them do not directly analyze pure protein but measure the amount of protein based on analysis of nitrogen. Therefore, it is important of selecting the appropriate analysis method considering the characteristics of samples.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.510-519
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• 2019

The 'Stable Isotope Analysis in R' (SIAR), one of the Bayesian mixing models for stable isotopes, has been proven to be useful for source apportionment of nitrates in rivers. In this study, the contribution ratios of nitrate sources were quantified by using the SIAR based on nitrogen and oxygen stable isotope measurements in the Yeongsan River. From the measurements, it was found that the values of δ¹⁵N-NO₃ and δ¹⁸O-NO₃ ranged from -8.2 ‰ to +13.4 ‰ and from +2.2 ‰ to +9.8 ‰, respectively. We further analyzed the contribution ratios of the five nitrate sources by using the SIAR. From the modeling results, the main nitrate source was found to be soil N (29.3 %), followed by sewage (26.7 %), manure (19.6 %), chemical fertilizer (17.9 %) and precipitation (6.3 %). From the results, it was found that the anthropogenic sources, i.e., sewage, manure and chemical fertilizer contribute 64.2% of the total nitrate inflow from the watershed. Due to the significant correlation of δ¹⁵N-NO₃ and lnNO₃^- in this study, the fractionation factors reflecting the biogeochemical processes of stable isotope ratios could be directly obtained. This may make the contribution ratios obtained in this study more precise. The fractionation factors were identified as +3.64 ± 0.91 ‰ for δ¹⁵N-NO₃ (p<0.01) and -5.67 ± 1.73 ‰ for δ¹⁸O-NO₃(p<0.01), respectively, and were applied in using the SIAR. The study showed that the stable isotope method using the SIAR could be applied to quantitatively calculate the contribution ratios of nitrate sources in the Yeongsan River.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.394-399
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• 2015

In this study, the Cu catalyst decorated with activated carbon fibers were prepared for improving $SO_2$ adsorption properties. Flame retardant and heat treatments of Lyocell fibers were carried out to obtain carbon fibers with high yield. The prepared carbon fibers were activated by KOH solution for the high specific surface area and controlled pore size to improve $SO_2$ adsorption properties. Copper nitrate was also used to introduce the Cu catalyst on the activated carbon fibers (ACFs), which can induce various reactions in the process; i) copper nitrate promotes the decomposition reaction of oxygen group on the carbon fiber and ii) oxygen radical is generated by the decomposition of copper oxide and nitrates to promote the activation reaction of carbon fibers. As a result, the micro and meso pores were formed and Cu catalysts evenly distributed on ACFs. By Cu-impregnation process, both the specific surface area and micropore volume of carbon fibers increased over 10% compared to those of ACFs only. Also, this resulted in an increase in $SO_2$ adsorption capacity over 149% than that of using the raw ACF. The improvement in $SO_2$ adsorption properties may be originated from the synergy effect of two properties; (i) the physical adsorption from micro, meso and specific surface area due to the transition metal catalyst effect appeared during Cu-impregnation process and ii) the chemical adsorption of $SO_2$ gas promoted by the Cu catalyst on ACFs.

• Korean Journal of Clinical Pharmacy
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• v.16 no.2
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• pp.113-122
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• 2006

Purpose: A retrospective study was performed to assess the efficacy and tolerance of ${\beta}-blocker$ administration in patients with heart failure and diabetes. Method: Records of 164 patients who were treated for the heart failure condition more than a year were studied retrospectively. Patients were divided into 4 groups based on their diabetes(DM) status and the administration of ${\beta}-blockers$ ($DM+{\beta}-blocker$ group: 14, DM w/o ${\beta}-blocker$: 19, No DM + ${\beta}-blocker$: 62, No DM + no ${\beta}-blocker$: 69). All patients had been receiving conventional therapy such as digoxin, ACE-I, ARB, diuretics, nitrates, aspirin, anticoagulants or lipid-lowering agents. The primary endpoints (death and hospital admission) were recorded during 1 year period and hemodynamic factors (HR, LVEF, SBP, DBP) were obtained from all patient groups before and after 12 months of ${\beta}-blocker$ treatment. To evaluate toxicity of ${\beta}-blocker$, SCr, BUN, AST, ALT and Alkaline phosphatase were obtained. Result: There were less death and hospital admission in DM + ${\beta}-blocker$ group than in DM without ${\beta}-blocker$ group (p=0.014). Relative risk of hospital admission for $DM+{\beta}-blocker$ group over no DM group was 1.17. Long term ${\beta}-blocker$ administration was associated with an improvement of heart rate in patients with DM (P< 0.02) with no significant improvement of LVEF, SBP, DBP. in DM patient. In patient without DM, ${\beta}-blocker$ was associated with improvement in LVEF, HR and DBP (P<0.01, P<0.03), but not in SBP. The incidence of toxicity was similar between the four group with no significant difference. Conculsion: Treatment of heart failure patients with ${\beta}-blocker$ appears to be beneficial in terms of hospital admission event and several hemodynamic factors. The toxicities of ${\beta}-blocker$ treatment were not significant and the treatment is generally well-tolerated in most of the heart failure patients.

• The Korean Journal of Mycology
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• v.13 no.4
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• pp.213-219
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• 1985

Among the eight strains, Pleurotus sajor-caju JAFM 1017 was selected as most potent producer of cellulolytic enzymes. The avicelase and CMCase activity reached maximum levels after 10 days, and ${\beta}-glucosidase$ activity reached a maximum level after 19 days. Among the various carbon sources, cellulose powder was most effective for the production of avicelase and ${\beta}-glucosidase$, and Na-CMC (sodium carboxymethyl cellulose) was good for the production of CMCase. The optimum concentration of cellulose powder was 1.0% (w/v), and glucose (1.0%) completely depressed the production of enzymes. Nitrates were effective for the production of enzymes, but nitrites did not support growth. The production of cellulolytic enzymes increased as the concentration of urea increased. The appropriate concentration of urea was 0.054% (w/v).

• Economic and Environmental Geology
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• v.45 no.1
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• pp.23-30
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• 2012

Major ions and nitrogen isotopic analyses were performed to determine the geochemical characters and to identify the source of nitrate of the shallow groundwater around agricultural field in the Youngdong area. The pH value of groundwater ranges from 60. to 8.2 (pH 7.2, mean). The average of EC, Eh and DO is 369 ${\mu}S/cm$ (70~729 ${\mu}S/cm$), 165.6 mV (29~383.2 mV), 4.3 mg/L (1.8~8.0 mg/L) respectively. The ion concentraion of groundwater was in the order of $Ca^{2+}$>$Na^{2+}$>$Mg^{2+}$>$K^{2+}$ and ${HCO_3}^-$>${NO_3}^-$>${SO_4}^{2-}$>$Cl^-$>$F^-$. Most of groundwater is Ca-$HCO_3$ type. The groundwater was affected by water-rock interaction in the shallow depth. Some groundwater is Ca-Cl or Na-$HCO_3$ (2.5%) type that was due to agricultural activities. The $NO_3$_N concetration of grondwater range from 10.2 mg/l to 26.9 mg/l, which show that this area is under nitrate pollution. ${\delta}^{15}N-NO_3$ value of the groundwater is the origins of are a combination of animal wastes and man-made fertilizers.