• Title/Summary/Keyword: 분배현상

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Does Altai Exist?: Area Studies and the Meaning of "Area" (알타이는 존재하는가: 지역연구와 지역의 의미)

  • Nam, Youngho
    • Journal of International Area Studies (JIAS)
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    • v.14 no.3
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    • pp.135-156
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    • 2010
  • While there are a few ways of giving meanings to the term, "Altai" ranging from a language family to a national residing around the Altai Mountains in Russian Federation, and to the people speaking the language or the whole area where they live, there have been controversial debates whether it is a meaningful categorization. This paper argues that the basic cause lying beneath the controversies is the underdevelopment of the subject that identifies itself as a representative of the whole area where the Altaic language family is spoken. It might be true, as some Korean and Russian scholars insist, that what deserves to be called Altaic culture (or civilization) has provided a common culture and mutual interactions with the people. However, the Altaic people failed to constitute themselves as a meaningful modern group, that is a nation, and they did not fully develop national consciousness, As a result, although their way of life may be regarded as an origin of various cultures across North-East Asia, Altaic culture is not sufficient to give a momentum to claim for cultural initiative in the region. This comes at least partly from the reconfiguration of ethnic identity through a Soviet type of modernization and its geopolitical situation surrounded by super-powers such as China and Russia, as well as belated import of religions such as Buddhism and Christianity. From a wide perspective, the trouble about delimiting an area is not unique in Altai, but universally found in anywhere, as far as area studies are concerned. The delimitation of an area is not a natural outcome of physical environment but an artificial production of how cultural-political relationships have been distributed. Therefore, while the case of Alai has its own specificities, its implications that a national or regional boundary in area studies should not be taken for granted may be applied to other areas.

Global Fate of Persistent Organic Pollutants: Multimedia Environmental Modelling and Model Improvement (잔류성 유기오염물질의 전 지구적 거동: 다매체 환경모델의 결과해석 및 개선방안)

  • Choi, Sung-Deuk;Chang, Yoon-Seok
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.1
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    • pp.24-31
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    • 2007
  • Global fates of polychlorinated biphenyl(PCB) were investigated with a fugacity based multimedia transport and fate model, Globe-POP(persistent organic pollutant). The accumulation of PCB was directly affected by the emission patterns of PCB into the atmosphere and surface areas of environmental compartments. Partition coefficients and reaction rates also influenced on the accumulation patterns of PCB. The emission patterns of PCB in 10 climate zones were consistent for the past 70 years, while the contribution of PCB in high-latitude zones to the globe has increased by cold condensation. Considering the amounts of emission and accumulation of PCB, the North temperature zone is regarded as an important source and sink of PCB. Meanwhile, in spite of no significant sources, POPs accumulate in Antarctic environments mainly due to extremely low temperature. Finally we suggested that a global water balance accounting for snow/ice should be incorporated into multimedia environmental models for high-latitude zones and polar regions with the seasonal snow pack and/or permanent ice caps. The modified model will be useful to evaluate the influence of climate change on the fate of POPs.

Ecological Risk Assessment of Residual Petroleum Hydrocarbons using a Foodweb Bioaccumulation Model (먹이연쇄 생물축적 모형을 이용한 잔류유류오염물질의 생태위해성평가)

  • Hwang, Sang-Il;Kwon, Jung-Hwan
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.11
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    • pp.947-956
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    • 2009
  • Residual petroleum hydrocarbons after an oil spill may accumulate in the marine benthic ecosystem due to their high hydrophobicity. A lot of monitoring data are required for the estimation of ecosystem exposure to residual petrochemicals in an ecological risk assessment in the affected region. To save time and cost, the environmental exposure to them in the affected ecosystem can also be assessed using a simple food-web bioaccumulation model. In this study, we evaluated residual concentrations of four selected polycyclic aromatic hydrocarbons (phenanthrene, anthracene, pyrene, and benzo[a]pyrene) in a hypothetic benthic ecosystem composed of six species under two exposure scenarios. Body-residue concentration ranged 5~250 mg/kg body depending on trophic positions in an extreme scenario in which the aqueous concentrations of PAHs were assumed to be one-tenth of their aqueous solubility. In addition, bioconcentration factors (BCFs) and bioaccumulation factors (BAFs) were evaluated for model species. The logarithm of bioconcentration factor (log BCF) linearly increased with increasing the logarithm of 1-octanol-water partition coefficient (log $K_{OW}$) until log $K_{OW}$ of 7.0, followed by a gradual decrease with further increase in log $K_{OW}$ without metabolic degradation. Biomagnification became significant when log $K_{OW}$ of a pollutant exceeded 5.0 in the model ecosystem, indicating that investigation of food-web structure should be critical to predict biomagnifications in the affected ecosystem because log $K_{OW}$ values of many petrochemicals are higher than 5.0. Although further research is required for better site-specific evaluation of exposure, the model simulation can be used to estimate the level of the ecosystem exposure to residual oil contaminants at the screening level.

A STUDY ON THE SHEAR BOND STRENGTH AND THE ANTICARIOGENICITY OF GLASS IONOMER CEMENT FOR BRACKET BONDING (브라켓 접착용 글라스 아이어노머 시멘트의 접착강도 및 항우식 효과에 관한 연구)

  • Kang, Yong-Joo;Kim, Yong-Kee
    • Journal of the korean academy of Pediatric Dentistry
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    • v.26 no.3
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    • pp.538-553
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    • 1999
  • The purpose of this study was to compare the shear bond strength and the anticariogenicity of glass ionomer cement with conventional bonding resin and fluoride releasing resin. After the shear bond strength test, scanning electron microscopic observation was performed for the evaluation of the fracture patterns in each group. Under the polarizing light microscope, artificially induced carious lesions were evaluated and the lesion depths of the samples were measured using image analyzing program(Image-Pro $PLUS^{TM}$, USA). 50 sound maxillary premolars were used for the bond strength test and another 30 for the anticariogenic test. Data collected were analyzed statistically using Oneway-ANOVA and Scheffe test. The results were as follows: 1. Glass ionomer groups(G-III, IV, V) generally showed the lower bond strength values than resin groups(G-I, II). 2. Among the two resin groups, G-I showed the higher bond strength than G-II without statistically significant difference between them(p>.05). 3. Within glass ionomer groups, statistical significance was found between G-III and G-V with the superior bond strength in G-V (p<.05). 4. Under the SEM, adhesive failure was the predominant fracture pattern in G-I and II, whereas cohesive failures were mainly observed in G-III. In G-IV and V, mixed type of pattern where the both fracture patterns coexisted within samples could be seen. 5. In evaluation of the depth of artificially developed carious lesion, glass ionomer group showed shallower depth than resin groups with statistical significance between G-III and G-I, II(p<.05). Among resin groups, fluoride releasing resin(G-II) showed the shallower depth than conventional resin(G-I)(p<.05).

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Study of Volcanic Gases and Hot Spring Water to Evaluate the Volcanic Activity of Mt. Baekdu (백두산 화산활동 평가를 위한 화산가스 및 온천수에 대한 연구)

  • Lee, Sangchul;Yun, Sung-Hyo
    • Economic and Environmental Geology
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    • v.50 no.2
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    • pp.171-180
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    • 2017
  • This study performed the analysis on the volcanic gases and hot spring waters from the Julong hot spring at Mt. Baekdu during the period from July 2015 to August 2016. Also, we confirmed the errors that $HCO_3{^-}$ concentrations of hot spring waters in the previous study (Lee et al. 2014) and tried to improve the problem. Dissolved $CO_2$ in hot spring waters was analyzed using gas chromatograph in Lee et al. (2014). Improving this, from 2015, we used TOC-IC to analysis dissolved $CO_2$. Also, we analyzed the $Na_2CO_3$ standard solutions of different concentrations using GC, and confirmed the correlation between the analytical concentrations and the real concentrations. However, because the analytical results of Julong hot spring water were in discord with the estimated values based on this correlation, we can't estimate the $HCO_3{^-}$ concentrations of 2014 samples. During the period of study, $CO_2/CH_4$ in volcanic gases are gradually decreased, and this can be interpreted in two different ways. The first interpretation is that the conditions inside the volcanic edifice are changing into more reduction conditions, and carbon in volcanic gases become more favorable to distribute into $CH_4$ or CO than $CO_2$. The second interpretation is that the interaction between volcanic gases and water becomes greater than past, and the concentrations of $CO_2$ which have much higher solubility in water decreased, relatively. In general, the effect of scrubbing of volcanic gas is strengthened during the quiet periods of volcanic activity rather than active periods. Meanwhile, the analysis of hot spring waters was done on the anion of acidic gases species, the major cation, and some trace elements (As, Cd, Re).

Sorption of PAHs by Soil Humins and Effect of Soil Inorganic Matrixs (PAHs의 토양휴민과의 흡착특성 및 토양 무기물의 영향 해석)

  • Lim, Dong-Min;Lee, Seung-Sik;Shin, Hyun-Sang
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.12
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    • pp.1337-1346
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    • 2006
  • Soil humin is the insoluble fraction of humic materials and play an important roles in the irreversible sorption of hydrophobic organic contaminants onto soil particles. However, there have been limited knowledge about the sorption and chemical properties of humin due to the difficulties in its separation from the inorganic matrix(mainly clays and oxides). In this study, de-ashed soil humins($Hu_1-Hu_6$) were isolated from a soil residues(Crude Hu) after removing alkali-soluble organic fractions followed by consecutive dissolution of the mineral matrix with 2%-HF for 2 hr. The humin samples were characterized by elemental analysis and $^{13}C$ NMR spectroscopic method and their sorption-desorption behavior for 1-naphthol were investigated from aqueous solution. The results were compared one another and that with peat humin. $^{13}C$ NMR spectra features indicate that the soil humin molecules are mainly made up of aliphatic carbons(>80% in total carbon) including carbohydrate, methylene chain. Freundlich sorption parameter, n was increased from 0.538 to 0.697 and organic carbon-normalized sorption coefficient(log $K_{OC}$) values also increased from 2.43 to 2.74 as inorganic matrix of the soil humin removed by HF de-ashing. The results suggest that inorganic phase in humin plays an important, indirect role in 1-naphthol sorption and the effects on the sorption non-linearity and intensity are analyzed by comparison between the results of soil humin and peat humin. Sorption-desorption hysteresis were also observed in all the humin samples and hysteresis index(HI) at low solute concentration($C_e$=0.1 mg/L) are in order of Peat humin(2.67)>De-ashed humin(0.74)>Crude Hu(0.59).

Evaluation of 1,1,2-trichloroethylene Removal Efficiency Using Composites of Nano-ZnO Photocatalyst and Various Organic Supports (다양한 유기계 지지체와 광촉매 Nano-ZnO 복합체를 활용한 1,1,2-trichloroethylene 제거 효율 평가)

  • Jang, Dae Gyu;Ahn, Hosang;Kim, Jeong Yeon;Ahn, Chang Hyuk;Lee, Saeromi;Kim, Jong Kyu;Joo, Jin Chul
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.11
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    • pp.771-780
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    • 2014
  • In this study, the various organic supports (i.e., silicone, acrylonitrile-butadiene-styrene, epoxy, and, butadiene rubber) with great sorption capacity of organic contaminants were chosen to develop nano-ZnO/organic composites (NZOCs) and to prevent the detachment of nano-ZnO particles. The water resistance of the developed NZOCs were evaluated, and the feasibility of the developed NZOCs were investigated by evaluating the removal efficiency of 1,1,2-trichloroethylene (TCE) in the aqueous phase. Based on the results from water-resistance experiments, long-term water treatment usage of all NZOCs was found to be feasible. According to the FE-SEM, EDX, and imaging analysis, nano-ZnO/butadiene rubber composite (NZBC) with various sizes and types of porosity and crack was measured to be coated with relatively homogeneously-distributed nano-ZnO particles whereas nano-ZnO/silicone composite (NZSC), nano-ZnO/ABS composite (NZAC), and nano-ZnO/epoxy composite (NZEC) with poorly-developed porosity and crack were measured to be coated with relatively heterogeneously-distributed nano-ZnO particles. The sorption capacity of NZBC was close to 60% relative to the initial concentration, and this result was mainly attributed to the amorphous structure of NZBC, hence the hydrophobic partitioning of TCE to the amorphous structure of NZBC intensively occurred. The removal efficiency of TCE in aqueous phase using NZBC was close to 99% relative to the initial concentration, and the removal efficiency of TCE was improved as the amount of NZBC increased. These results stemmed from the synergistic mechanisms with great sorption capability of butadiene rubber and superior photocatalytic activities of nano-ZnO. Finally, the removal efficiency of TCE in aqueous phase using NZBC was well represented by linear model ($R^2{\geq}0.936$), and the $K_{app}$ values of NZBC were from 2.64 to 3.85 times greater than those of $K_{photolysis}$, indicating that butadiene rubber was found to be the suitable organic supporting materials with enhanced sorption capacity and without inhibition of photocatalytic activities of nano-ZnO.

A Study on the Correlations between Molecular Structures of Soil Humins and Sorption Properties of Phenanthrene (토양 휴민(Humin)의 분자구조 특성과 Phenanthrene 흡착상수와의 상관관계에 대한 연구)

  • Lee, Doo-Hee;Eom, Won-Suk;Shin, Hyun-Sang
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.12
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    • pp.897-905
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    • 2013
  • In this study, sorption coefficients (${\log}K_{OC}$, n) for the binding of phenanthrene (PHE) to soil humins, insoluble fraction of soil humc substances (HS), were determined and relationship between the sorption coefficients and structural characteristics of the soil humins were investigated. The soil humins used in the present study were isolated from 7 different soils including 5 domestic soils, an IHSS standard and a peat soil, and characterized by elemental analysis and CPMAS $^{13}C$ NMR method. $^{13}C$ NMR spectral features indicate that the soil humins are mainly made up of aliphatic carbons (57.1~72.3% in total carbon) with high alkyl-C moiety, and the alkyl-C contents ($C_{Al-H,C}$, %) was in order of granite soil Hu (26~42%) > volcanic ash soil, HL Hu (23.9%) > Peat Hu (14.0%). The results of correlation study show that a positive relationship ($r^2$ = 0.77, p < 0.05) between organic carbon normalized-sorption coefficients ($K_{OC}$, mL/g) and alkyl-C contents($C_{Al-H,C}$, %), while negative relationship ($r^2$ = (-)0.74, p < 0.05) between Freundlich sorption parameter (n) and H,C-substituted aromatic carbon contents ($C_{Ar-H,C}$, %). The magnitude of $K_{OC}$ values are also negatively well correlated with polarity index (e.g., PI, N + O)/C) ($r^2$ = (-)0.74, p < 0.1). These results suggest that the binding capacity (e.g., $K_{OC}$) for PHE is increased in soil humin molecules having high contents of alkyl-C or lower polarity, and nonlinear sorption for PHE increased as the H,C-substituted aromatic carbon contents ($C_{Ar-H,C}$, %) in the soil humins increased. The PHE sorption characteristics on soil humins are discussed based on the dual reactive mode of sorption model.

Ion-Exchange Chromatography of Some Toxic Heavy Metal Ions (인체유해 중금속이온의 이온교환 크로마토그라피)

  • Lee, Dai Woon;Yu, Euy Kyung
    • 한국해양학회지
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    • v.10 no.1
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    • pp.33-40
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    • 1975
  • The ion exchange sorption and elution behavior of toxic heavy metal ions, such as Hg(II) and Zn(II), have been studied in aqueous and methanolic media of MCl (M: K, Na and NH$\_$4/). The ion exchange resins studied are Dowex 1-X8, Cl$\^$-/ (50-100 or 200-400 mesh) and Dowex 50W-X8, M$\^$+/ form (M: K, Na, NH$\_$4/ and H). the sorption and elution of metal ion on the resin is largely due to the formation of the anionic chlororocomplex of metal ion. The addition of methanol in the medium contributes markedly to the distribution data. In order to apply this work for the treatment of polluted sea water with toxic heavy metal ions, removal experiment of the metal ions from the synthetic sample solution was investigated.

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Alteration Zoning, Mineral Assemblage and Geochemistry of the Hydrothermal Clay Deposits Related to Cretaceous Felsic Magmatism in the Haenam Area, Southwest Korea (한국 서남부, 해남지역에서 백악기 산성마그마티즘에 관련된 열수점토광상의 누대분배, 광물조합의 지구화학적 연구)

  • Kim, In Joon
    • Economic and Environmental Geology
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    • v.25 no.4
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    • pp.397-416
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    • 1992
  • In the present study, three clay deposits, named the Seongsan, Ogmaesan and Haenam deposits, were investigated. The altered zones are recognized in the hydrothermally altered rocks of the clay deposits from the center of the alteration to the margin: Kaolin, Kaolin-Quartz, Quartz, Sericite and Chlorite zones in the Seongsan deposits; Quartz zone, Alunite zone, Kaolin zone, Sericite zone and Chlorite zone in the Ogmaesan deposits; Quartz zone, Pyrophyllite zone, Sericite zone and Chlorite zone in the Haenam deposits. These zones can be grouped into two types of alteration: Acidic alteration such as Pyrophyllite zone, Alunite zone, Quartz zone, Kaolin zone, Kaolin-Quartz zone and a part of Sericite zone; Propylitic alteration such as Chlorite zone and a part of Sericite zone. All clay deposits belong to high-sulfidation (acid-sulfate) system. The rocks of the acidic alterations are composed of pyrophyllite, alunite, kaolin minerals, sericite, quartz and pyrite. On the basis of bulk chemical compositions, it was found that some components such as $SiO_2$, $TiO_2$, $Fe_2O_3$, FeO, MgO, CaO, $K_2O$ and $Na_2O$ were mobilized considerably from the original rocks. The mobility of these major elements is related to, and controls, mineral assemblages in each altered zone. Polytypes of sericite are determined as $2M_1$ and 1M by X-ray diffraction method. The amount of $2M_1$ is nearly equal to that of 1M in the Seongsan deposits whereas $2M_1$ is less and higher than that of 1M in the Ogmaesan and the Haenam deposits. These facts indicate that formation temperature of sericite is relatively high in the Haenam deposits, moderate in the Seongsan deposits, and low in the Ogmaesan deposits. The ratios of Na/(K+Na) for alunite in the Ogmaesan deposits determined by electron microprobe analyzer (EPMA) are higher than those in the Seongsan deposits. Thus, the alunite of the Ogmaesan deposits must have been formed from the solutions with relatively high aqueous Na/(K+Na) ratios and low pH at a high temperature rather than that of the Seongsan deposits. From all data, it is clarified that alunite is hypogene in origin, and has been formed by oxidation of hydrogen sulfide in the steam-heated environment, and that alunite has been produced by the spectacular solfataric alteration observed at the surface of some present-day hydrothermal systems.

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