• Analytical Science and Technology
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• v.14 no.2
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• pp.180-190
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• 2001

Oder-active compounds are complex in a sample. These compounds are usually analyzed by GC or GC/MSD while such analytical measurement can quantify specific volatile organic compounds, it has limitations in identifying odor-active compounds. To resolve this problem, GC-Sniffing or GC-Olfactometry method has been attempted. In this study, GC/FID/Olfactometry system was developed. This system can simultaneously sniff and detect GC effluents by traditional GC combined with human olfactory system. The time gap between FID and ODP response was dependent on the kinds and concentrations of chemicals and panels, with more volatile, stronger and shorten breath cycle panel showing narrow time gap. Thus, clear relationship between FID and ODP should be considered to identify the odor-active compounds.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.557-566
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• 2019

Paldang is a river reservoir in the Midwest of Korea, which is a drinking water source for the metropolitan area. Since the Paldang Reservoir is shallow, and has a short hydraulic residence time, its water quality is directly impacted by two incoming rivers, the north Han River (NHR) and the south Han River (SHR). The NHR has different seasonal patterns of water temperature from the SHR because the NHR is greatly impacted by the discharge water from upstream dams. The electrical conductivity (EC) and other material concentrations of the SHR are usually higher than those of the NHR because its basin is limestone-based. The difference in water temperature in the two rivers causes density flow, and the distribution of the EC within the reservoir can be an indicator for monitoring density flow. From the vertical gradient of the EC at the dam site, from spring to fall, it was confirmed that the SHR flowed into the upper layer, and the NHR flowed into the lower layer, and vice versa at other times. The relative difference (RD) of the EC between the upper layer and the lower layer at the dam site was used as an indicator for density flow. The RD of the EC showed a very significant correlation with the RD of total organic carbon (r = 0.70, p < 0.001) and the RD of total nitrogen (r = 0.58, p < 0.01). This relationship is based on the assumption that the difference in electrical conductivity and water quality between the SHR and the NHR is constant. However, in many cases this assumption is inconsistent. Thus, further study is needed on more suitable indicators to evaluate the impact of density flow on water quality.

• International Journal of Advanced Culture Technology
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• v.5 no.4
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• pp.1-9
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• 2017

This study of Cho Ji - Hoon's Poem "Falling Flowers" was attempted to find the mechanism of poetic healing and utilize it for literary therapy. In this study, I examined how Cho Ji-Hoon's poem "Falling Flowers" encoded crying. Especially, we focused on the organic relationship of each layer represented by poem and put emotional codes on the layer of functor and argument. The results are as follow. It represents the Separation Layer of 1-3strophes, 4-6strophes constitute the Time Layer, and 7-9strophes the Sadness Layer. This poem proceeds the encoding of the sentence in which the crying of cuckoo in the 1-3strophes transforms into the crying of the poetic narrator in the last 9strophe. The relation of emotional layers in this poem is in the same function relations as "(1-3strophes) ${\subset}$ (4-6strophes) ${\subset}$ (7-9strophes)". Since these functional relations consist of the encoding of sadness, encrypts emotion signals of sadness as "U+U+U" becomes "UUU". 1-3strophes' U is the cry of the cuckoo, and U of the 4-6strophes is blood cry. Therefore, "UUU" is the blood cry of poetic narrator. This Cho Ji-Hoon's poem has a Han(恨) at its base. So, as Cho Ji-Hoon's poem "Falling Flowers" is uttered, the poetic mechanism of U, the code of sadness, is amplified. Then we get caught up in the emotions we want to cry. The poetic catharsis of "crying" is providing the effect of literary therapy. In the future, it will be possible to develop a more effective literary therapy technique by developing a literary therapy program like this poetic structure.

• Composites Research
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• v.30 no.5
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• pp.261-266
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• 2017

Polymer composites are materials in which various fillers are uniformly dispersed on the basis of organic resin. They have excellent processability and diversity for industrial products. Recently, as carbon nanomaterials are developed, there is a great deal of effort to use them as reinforcing fillers to fabricate high performance composite materials. In order to transfer the inherent properties of fillers into composite materials as much as possible, the good dispersion and orientation of fillers, and favorable interfacial interaction between fillers and matrix are considered to be very important. In this review article, we intent to derive and explain the relationship between surface chemical structure of fillers and physical properties of composites as a strategy of high strength and toughness of graphenebased polyimide composites.

• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.63-74
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• 2015

The purpose of this study is to provide the basis information for ecological conservation and restoration of Jangdo wetland conservation area through the survey of vegetation diversity and spatial distribution characteristics. Syntaxonomic account of plant communities were carried out field survey by Z.-M. school method at 14 sites and relationship analysis between plant community and environment variables with Principal Coordinate Analysis (PCoA). Based on the floristic composition, all the plots were classified into xeric and hydric type and arranged in seven plant communities. Spatial distribution of plant communities is determined primarily by the soil moisture condition and amount of organic matter. Hydric vegetation is around 8% ($7,337m^2$) of the protected area and distributed swamp forest of dominating willows under 18 years. Proliferation of willows are recognised extended from edge to centre after in 1990's caused by fallow and control of livestock grazing on wetland. Jangdo wetland will have to readjust the protection boundary because wet meadow zone and swamp forest have been distributed outside the protection area.

• Analytical Science and Technology
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• v.12 no.5
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• pp.387-396
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• 1999

The retention behavior of Cot(II)-dithiocarbamate(DTC) chelates in reversed phase high performance liquid chromatography was investigated. Enthalpy and entropy of chelates transfer from the mobile phase to the stationary phase were calculated from retention data using van't Hoff plots. The dependence of In k' on enthalpy was decreased with increasing organic solvent ratio on the mobile phase. The compensation temperatures(${\beta}$) calculated from the slope of $-{\Delta}H^0$ vs In k' were in the range of 756.3-888.5 K. From these results. it was found that the retention mechanism of DTC chelates was invariant under the various temperatures and was largely affected by the solvophobie effect. Liniear relationship between S index and log k' in emprical retention equation, $log\;k^{\prime}=log\;{k_w}^{\prime}-S_{\varphi}$ showed that S index was influenced mainly by the interaction between DTC chelates and the mobile phase.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.819-825
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• 2000

The physico-chemical characteristics and the combustion activities of a waste automotive catalyst were carried out in this study. The physico-chemical characteristics of waste automotive catalyst was examined by EA(Elemental analysis), ICP-AES (Inductively coupled plasma-atomic emission spectrophotometer), and XRD(X-ray diffraction) analysis. Carbon deposit amount was higher in front brick than rear brick of catalyst, and increased with mileage. The content of Pt. Pd and Rh in waste automotive catalyst was different from the car manufacturing company. The combustion activities of waste automotive catalyst were investigated for acetaldehyde as a model VOC in a fixed bed reactor at atmospheric pressure. The catalytic activity of rear brick for acetaldehyde combustion was better than front brick of waste automotive catalyst. The catalytic activity of waste automotive catalyst for acetaldehyde combustion decreased with mileage. The linear relationship between catalytic activity and mileage was negative and has a very excellent correlation. Finally, the waste automotive catalyst has a good catalytic activity for acetaldehyde combustion. and can be used to control of small emission source.

• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.70-79
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• 2015

A sample of soil humic acid (HA) was divided by ultrafiltration (UF) into five fractions of different molecular size (UF₁: > 300, UF₂: 100~300, UF₃: 30~100, UF₄: 10~30, UF₅: 1~10 kilodaltons). Apparent average molecular weight (M_w) of the HA fractions were measured using high performance size exclusion chromatography (HPSEC), and the chemical and structural properties of the five HA fractions were characterized by elemental compositions (H/C, O/C and w ((2O + 3NH)/ C)) and ultraviolet-visible absorption ratios (SUVA, A_4/6). The organic carbon normalized-sorption coefficients (Koc) for the binding of phenanthrene to the HA fractions were determined by fluorescence quenching and relationship between the sorption coefficients and structural characteristics of the HA fractions were investigated. The elemental analysis and UV-vis spectral data indicated that the HA fractions with higher molecular weights have grater aliphatic character and lower contents of oxygen, while the HA fractions with lower molecular size have greater aromatic character and molecular polarity that correspond to greater SUVA and internal oxidation values (w). The log Koc values (L/kg C) were gradual increased from 4.45 for UF₅ to 4.87 for UF1. The correlation study between the structural descriptors of the HA fractions and log Koc values of phenanthrene show that the magnitude of Koc values positively correlated with $M_w$ and H/C, while negatively correlated with the independent descriptors of the O/C, w, SUVA and A_4/6.

• Journal of Preventive Medicine and Public Health
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• v.43 no.1
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• pp.1-8
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• 2010

Objectives: This study was performed to investigate if organochlorine pesticides (OCPs) were associated with metabolic syndrome and insulin resistance among non-diabetes. Methods: Among subjects who participated in a community-based health survey, 50 non-diabetic subjects with metabolic syndrome and 50 normal controls were selected. Insulin resistance was measured by the homeostasis model assessment (HOMA-IR). Eight OCPs were selected. Results: After adjusting for confounders except for body mass index (BMI), beta-hexachlorocyclohexane ($\beta$-HCH) and heptachlor epoxide were positively associated with metabolic syndrome. Odds ratios across tertiles of $\beta$-HCH and heptachlor epoxide were 1.0, 3.2 and 4.4, and 1.0, 4.0 and 6.0, respectively (p for trend = 0.01 and <0.01). After additional adjustment for body mass index (BMI), heptachlor epoxide still showed an increasing trend with adjusted odds ratios of 1.0, 4.1, and 4.6 (p for trend = 0.10). When the five components of metabolic syndrome (with the definition of high fasting glucose ($\geq$ 100 mg/dL) were separately analyzed, all components were positively, but not significantly, associated with heptachlor epoxide. As the serum concentration of heptachlor epoxide increased, HOMA-IR increased significantly in subjects with metabolic syndrome even after adjusting for BMI (p value <0.05 and <0.01). Conclusions: Despite the small sample size, this study suggests that the background exposure to some OCPs may be associated with metabolic syndrome.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.2
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• pp.111-115
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• 2000

$BaTIO_3$ thin films were prepared on (100) $BaTIO_3$ substrates by coating- pyrolysis process using metal-organic compounds of Ba and Ti. The amorphous films prefired at $450^{\circ}C$were crystallized above $700^{\circ}C$ under oxygen partial pressure of $2\times 10^{-4}$. The lattice parameters of the perpendicular axis for the $BaTIO_3$ thin films heat-treated below $800^{\circ}C$ were closer to a value of cubic $BaTIO_3$, whereas those above $800^{\circ}C$ were closer to a value of tetragonal BaTiG. The results of XRD P scan and pole-figure analyses indicated that BaTiO, thin films have an epitaxial relationship with the $SrTiO_3$ substrates. The $BaTIO_3$thin films annealed at$800^{\circ}C$ showed the surface with island-like grains about 0.4$mu \textrm{m}$ and the cross section of 0.8 $mu \textrm{m}$ thickness with granular grains.