• Korean journal of applied entomology
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• v.43 no.4 s.137
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• pp.323-328
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• 2004

These studies were carried out to investigate the fumigation and contact toxicities of spearmint oil (Mentha spicata) against adults of greenhouse whitefly, Trialeurodes vaporariorum and sweet-potato whitefly, Bemisia tabaci. And we carried out the constituent analysis of spearmint oil using gas chromatograph (GC) and gas chromatograph mass spectrometry (GC/MS). Spearmint oil showed $99.1\%,\;91.7\%,\;41.1\%$ fumigation toxicity against T. vaporariorum adults at $10{\mu}L/954mL,\;5{\mu}L/954mL,\;1{\mu}L/954mL$ air concentration, respectively. In case of B. tabaci adults, spearmint oil showed $100\%,\;100\%,\;61.3\%$ fumigation toxicity, respectively. However, spearmint oil showed < $30\%$ contact toxicity against adults of T. vaporariorum and B. tabaci. Through the constituent analysis using GC and GC/MS, we confirmed main constituents of spearmint oil were limonene ($16.1\%$), ${\gamma}$-terpinene($13.8\%$), ${\rho}$-cymene($5.8\%$), 3-octanol($6.9\%$), carvone($40.9\%$). Carvone, major constituent of spearmint oil, also showed $100\%$ fumigation toxicity at $10{\mu}L/954mL$ air concentration.

• Analytical Science and Technology
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• v.29 no.6
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• pp.293-299
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• 2016

$^{137}Cs$ was investigated in river bottom sediments located in South-Han River basin and it was compared with international case studies to estimate the concentration level of $^{137}Cs$ in river sediment of Korea. The obtained values of $^{137}Cs$ which was analyzed by gamma-ray spectrometry were in the range of <$MDA{\sim}3.80{\pm}0.14Bq/kg{\cdot}dry$ and similar to the $^{137}Cs$ activities in soil of Korea. According to international case studies, $^{137}Cs$ activities were between 3.7 to $15,396Bq/kg{\cdot}dry$, when pollutants such as nuclear power plant accidents and radiation leaks were present near the rivers. The $^{137}Cs$ activities showed a variety of distribution depending on the country, when pollution occurs and survey time. Also, $^{137}Cs$ activities of river sediments without pollution sources were mostly less than $10Bq/kg{\cdot}dry$ in other countries. It was comparable with the obtained $^{137}Cs$ activities in this study. The obtained values provide useful information on the background concentration of $^{137}Cs$ in river sediment and will be able to use a basis for determining contamination of $^{137}Cs$ in the river.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.315-321
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• 2010

Malassezia furfur is an important causal factor for seborrheic dermatitis. Nowadays, the drugs available to treat this fungal infection are few. Several studies have documented the biological activity of essential oils. However, its antifungal properties are not completely understood, especially its anti-Malassezia activity. The aim of this study were to evaluate the effect of the plant essential oils on the growth of M. furfur using disk diffusion method and analyze by Gas chromatography-mass spectrometry (GC-MS) most active essential oils. In first screening, the 17 plant essential oils have possesses inhibitory activity against M. furfur at 2 mg/mL. Among the plant essential oils, oil of Citrus auranifoli was most active against M. furfur and its activity showed dose dependency. This anti-malassezial activity was high than that of itraconazole at 2 mg/mL. Oil of Citrus auranifolia also was phytochemically examined by GC-MS analysis, its main constituents were identified as limonene, ${\gamma}$-terpinene and terpinolene. It can be concluded that essential oils of Citrus auranifolia may have interesting applications to control fungal-derived diseases.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.233-237
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• 2008

The essential oil was obtained from the aerial part of Rhododendon mucronulatum Turcz. var. ciliatum Nakai by steam distillation, samples were collected by headspace (HS) and solid-phase microextraction (SPME) methods, and the compositions of the oil were analyzed by gas chromatography-mass spectrometry (GC-MS). Nineteen constituents were identified from the essential oil: 15 carbohydrates, 3 alcohols, and 1 acetates. Major constituents were 2-${\beta}$-pinene (16.1%), camphene (11.9%), ${\delta}$-3-carene (11.4%), d,l-limonene (9.5%), and ${\gamma}$-terpinene (9.5%). By SPME extraction, seventeen constituents were identified: 13 hydrocarbons, 1 alcohol, 1 nitrogen-containing compound, 1 acetate, and 1 amine. Major constituents of the SPME-extracted sample were cam phene (19.6%), 2-${\beta}$-pinene (18.0%), ${\delta}$-3-carene (17.4%), trimethyl hydrazine (9.7%), ${\gamma}$-terpinene (8.5%), and d,l-limonene (5.5%). By HS extraction, thirteen constituents were identified: 11 hydrocarbons, 1 alcohol, and 1 nitrogen-containing compound. Major constituents of the HS-extracted sample were camphene (25.8%), ${\delta}$-3-carene (24.8%), 2-${\beta}$-pinene (20.2%), d,l-limonene (5.4%), tricyclene (5.1%) and trimethyl hydrazine (4.6%). The fragrance of the essential oil was coniferous, balsamic, and woody, and the $IC_{50}$ value of the essential oil was 0.030 ${\mu}g/mg$ in MTT assay using UaCaT keratinocyte cell line.

• Journal of the Korean Chemical Society
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• v.18 no.1
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• pp.40-46
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• 1974

The fission neutron reactions of $^{47}Ti(n.p)^{47}Sc$ and $^{93}Nb(n,{\alpha})^{90m}Y$, along with epicadmium neutron reaction of $^{96}Zr(n,{\gamma})^{97}Zr$ were used for the simultaneous determination of Ti, Nb and Zr in synthetic mixture. Prior to neutron irradiation, Ti, Zr and Nb in the mixture were separated together in one group through the cation exchange column of Dowex $50{\times}8$ resin using 0.5 M ${\alpha}$-hydroxy-iso-butyric acid as the eluent. After irradiation of the eluate the product nuclides, $^{97}Zr$, ^{47}Sc$ and ^{90m}Y$, were eluted sequentially through the same column with 0.5 M ${\alpha}$-HIBA, 0.5 M ${\alpha}$-HIBA-1 N HNO_3 and 0.5 M ${\alpha}$-HIBA-2 N HNO_3$ solution, respectively. The gamma-ray spectrometry was used for the measurement of the gamma-ray activities of the eluted nuclides. The detection limits of Nb, Ti and Zr were found to be 0.2 %, 0.01 % and 0.002 %, respectively.

• Korean Journal of Medicinal Crop Science
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• v.22 no.3
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• pp.188-195
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• 2014

This study was carried to investigate the effect of illite addition on the growth, bioactive components and volatile compounds of leaf on Saururus chinensis Baill cultivation in greenhouse. Illite addition on Saururus chinensis Baill cultivation resulted no significant effects on the aerial part. However, the root part was highest in 5% illite addition group. Crude oil and ash amount increased as illite additives was increased. Ca of inorganics and free sugars contents were highest in 5% and 20% illite addition, respectively. Hyperoside and isoquercetin of available component on leaf were highest in 5% illite addition group, 4.02mg/g and 4.31mg/g, respectively. The volatile compounds in Saururus chinensis Baill leaf cultured with illite addition amounts were isolated by solid-phase microextraction fiber (polydimethysiloxane $65{\mu}m$) and identifed by gas chromatogtaphy mass spectrometry. As the results, the 22 volatile compounds were identified from in Saururus chinensis Baill leaf and major volatile compounds were the ${\alpha}$-cadinol (18.50%), myristicin (16.46%), methyl-9-methyl-tetradecanoate (10.22%), and ${\gamma}$-muurolene (9.75%). Especially, the content of ${\alpha}$-cadinol was highest in 5% illite addition group and ${\gamma}$-muurolene on overall illite addition group was lower than no addition group.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.31-36
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• 2013

The radioactive gas radon ($^{222}Rn$), which is generated from the decay process of uranium ($^{238}U$) originating from the soil of more than 85 percent higher the porosity of the soil, the soil can radiate out the possibility that many isotopes. In order to protect the human body from radon, above all, the development of accurate measurement techniques to formulate appropriate measures should be followed. This study Gamma-ray spectrometry using a high purity germanium (HPGe) detector, if you want to measure radon unstable the nature radiation of the background problems can be reduced, radium and radon daughter nuclides after radioactive equilibrium leads to Radon concentration was measured, the soil samples from the Gamma-ray emitting nuclides, and the energy spectrum is analyzed.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.55-63
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• 1999

For understanding the radiation environment in the land of Korea and acquiring baseline data to be referred to at the time of a nuclear accident, cultivated soils in the $0{\sim}15cm$ layer were sampled at 33 sites scattered all over the country and $^{137}Cs$ concentrations were measured by $\gamma$-spectrometry. The soil $^{137}Cs$ concentrations were in the range of $0.7{\sim}17.7$ Bq/kg-dry in the paddy field and $1.2{\sim}27.8$ Bq/kg-dry in the upland field, The means were 6.9 Bq/kg-dry and 9.9 Bq/kg-dry, respectively. In the paddy field, the soil $^{137}Cs$ concentration was positively correlated to the organic matter content and negatively correlated to the clay content. In the upland field, it was positively correlated to the cation exchange capacity. It was revealed that soil organic matter play an important role in the change of soil $^{137}Cs$ concentration.

• Journal of Radiation Protection and Research
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• v.12 no.1
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• pp.48-53
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• 1987

The manganous sulphate bath method is widely used for measurements of neutron source strength. In this study, the analytical chemistry method based on the argon supported inductively coupled plasmas emission spectrometry was used for examining the impurity contents of domestic $MnSO_4{\cdot}H_2O$ the product of Chemical Industry, to induce $^{55}Mn(n,{\gamma})^{56}$ Mn reactions. From the analytical results, mainly potassium, cobalt, and zinc as well as trace amounts of cadmium, lithium, etc. have turned out to be the relevant impurities absorbing the neutrons, and the fraction of neutrons absorbed by the total impurities was calculated. The value obtained was about 1.37% of the neutrons captured by manganese.

• Korean Journal of Materials Research
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• v.15 no.8
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• pp.508-513
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• 2005

[ $TiO_2-Fe_2O_3$ ] nanocomposite powders for magnetic photocatalyst were synthesized by sol-gel process, in which $TiO_2$ photocatalytic layer was formed on the surface of $\gamma-Fe_2O_3$ magnetic core. Transmission electron microscopy (TEM) observation and X-ray diffractometry (XRD) analysis revealed that$\gamma-Fe_2O_3$ nanoparticles, $10\~20nm$ in diameter, were coated by $TiO_2$ shell of 5nm in thickness and $TiO_2$ was anatase phase. Also hydroxyl group (-OH) used to decompose organic compounds was detected by Fourier transformation infrared spectrometry(FT-IR) analysis. UV-Visible spectrophotometry results showed that light absorption occurred in the wavelength range of $400\~700 nm$, and the band gap energy $(E_g)$ of powder was 1.8 eV. Finally it was found that the coercivity $(H({ci})$ and saturation magnetization $(M_s)$ of the powder were 79 Oe and 14.8 emu/g, respectively as experimental vibrating sample magnetometer (VSM) measurements.