• Journal of Environmental Science International
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• v.14 no.8
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• pp.749-760
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• 2005

This study examines the local ozone photochemistry in the urban air. The photochemical formation and destruction of ozone was modeled using a photochemical box model. For the model prediction of ozone budget, measurements were carried out from an urban monitoring station in Seoul ($37.6^{\circ}N,\;127^{\circ}E$), Korea for intensive sampling time period (Jun. $1\~15$, 2003). Photochemical process is likely to play significant role in higher ozone concentrations during the sampling period. The results of model simulation indicated that photochemical ozone production pathway was the reaction of NO with $HO_2$ while ozone destruction was mainly controlled by a photochemical destruction pathway, a reaction of $H_2O$ with $O(^1D).$ The contribution of NMHCs to formation and destruction of ozone in the urban was significant. This was entirely different from remote marine environment. The rates of net photochemical ozone production ranged from 0.1 to 1.3 ppbv $h^{-1}$ during the study period.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.2
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• pp.77-127
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• 1999

활성 산소종은 노화, 특히 피부노화의 원인 물질로 작용하고 있다. 피부는 자외선에 노출되어 있어 활성 산소종을 만드는 광화학적 반응들이 계속해서 일어나고 있다. 이들 활성 산소종들은 피부 세포 및 조직 손상을 주도한다. 이들은 항산화 효소와 비효소적 항산화제들로 구성된 항산화 방어망을 파괴함으로써 산화제/항산화제 균형을 산화 상태 쪽으로 기울게 한다. 결과적으로 계속된 산화적 스트레스는 지질 과산화, 단백질 산화, 간질 성분을 파괴시키는 단백질분해효소의 활성화, 탄력 섬유인 콜라겐과 엘라스틴의 사슬절단 및 비정상적인 교차결합, 히아루론산 사슬의 절단, 멜라닌 생성반웅 촉진, DNA 산화와 같은 생체 구성 성분들의 손상을 야기시킨다. 결국에는 탄력감수 주름살 및 기미.주근깨 둥으로 특징 지워지는 피부노화가 가속화된다. 따라서 피부노화 방지를 위해서는, 과잉의 활성 산소종 생성을 억제하고 또한 생성된 활성산소를 효율적으로 제거할 수 있는 시스템이 화장품의 처방에 반드시 포함될 필요가 있다. 즉, 산화제/항산화제 밸런스가 유지되는 피부의 항산화 방어 시스템 구축이 필요하다. 피부노화 방지에 있어서 천연물의 역할로 (1) 자외선 흡수제로서의 역할, (2) 항산화제로서의 역할, (3) 주름 개선제로서의 역할, (4) 미백제로서의 역할, (5) 항균\ulcorner항염작용 및면역 조절제로서의 역할에 대하여 살펴 보았다. 21세기는 본격적으로 기능성 화장품 시대가 개막될 것으로 예측하고 있다. 이에 맞춰 천연물들은 피부노화를 방지하는데 주도적인 역할을 할 것으로 기대된다.

• Economic and Environmental Geology
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• v.22 no.3
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• pp.221-235
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• 1989

Gold-silver mineralization of the Goryeong-Waegwan area was deposited in three stages of quartz and calcite veins which fill fissures in Cretaceous sedimentary rocks of the Sindong Group. Radiometric dating indicates that mineralization is Late Cretaceous age(98 Ma) likely associated genetically with intrusion of a small biotite granite stock. Fluid inclusion and stable isotope data indicate that Au-Ag ore was deposited at temperatures between $280^{\circ}C$ and $230^{\circ}C$ from fluids with salinities between 1.7 and 8.7 equiv.wt.% NaCl. Evidence of boiling indicates pressures of <100 bars, corresponding to depths of 425 and 1,150m, respectively, assuming lithostatic and hydrostatic loads. Within ore stage I there is an apparent decrease in ${\delta}^{34}S$ values of $H_2S$ with paragenetic time, from +1.4 to -2.5 per mil. This pattern was likely achieved through progressive increases in pH and activity of oxygen accompanying boiling. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids(${\delta}D$ = -90 to -100 per mil; ${\delta}^{18}O$ = +3.9 to -11.4 per mil) indicate meteoric water dominance, approaching unex-changed meteoric water values. Au-Ag deposition is thought to be the result of cooling and dilution of a boiling fluid through mixing with less evolved meteoric waters.

• Resources Recycling
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• v.27 no.1
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• pp.64-73
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• 2018

This study aims to analysis the environmental impact on waste catalyst recycling technology using entire life cycle assessment. Environmental impacts consist of the five categories of impacts: global warming, resource depletion, acidification, eutrophication, and photochemical oxide production. The waste catalyst recycling presently have a GWP 3.53 ton $CO_2$ equivalent/ton, a ADP 0.017 ton Sb equivalent/ton, a AP 0.051 $SO_2$ equivalent/ton, a EP 0.0092 $PO{_4}^{3-}$ equivalent/ton, a 0.0019 ton $C_2H_4$ equivalent/ton. The smelting reduction process is the greatest contributor to all categories of environmental impacts in waste catalyst recycling. Electricity used in the smelting reduction process is the major contributor of all impact categories.

• The Korean Journal of Mycology
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• v.17 no.4
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• pp.202-208
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• 1989

The photochemical reaction of harmaline and N-methylmaleimide has been investigated by spectroscopic methods. A photoproduct was isolated from the irradiation mixture of harmaline and N-methylmaleimide. Spectroscopic results suggested that the amine group of harmaline was added photochemically to the double C=C bond of N-methylmaleimide. This synthesized harmaline derivative has a biological toxicity, because it inhibits the growth of some yeasts and photosynthetic bacteria.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.53-71
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• 1986

Detailed studies of regional geology and geochemistry of the tungsten mineralisation of Ogbang mine were carried out; in particular geochemical trends of major and trace elements of different lithological units, in comparison with those of the Sangdong area, together with igneous plutons in the area. The Ogbang deposit is in a pegmatitic association localised only in amphibolites whilst pegmatites in adjacent schists and gneisses are barren. The tungsten is geochemically accompanied by increase of $K_2O$, $Na_2O$ and Rb, and depletion of Sr. The trend of Rb/Sr ratio to the type of mineralisation, in commonly seen in the mineralised granites of the world, suggests that the tungsten in the Ogbang pegmatites was supplied by hydrothermal processes which at the same time caused Rb enrichment and Sr depletion. These trend could be of use in the search for new ore bodies in common with those of mineralised granitic or pegmatitic host rocks. There is no evidence that the granites in the area have any genetic influence spacially and temporarily on the initial scheelite formation.

• Economic and Environmental Geology
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• v.55 no.4
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• pp.339-352
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• 2022

As environmental criteria items are increased or strengthened, cases of heavy metal contamination by geogenic origin are increasing, and the need to distinguish between natural and anthropogenic origins in soil or groundwater exceeding the standard is increasing. In this study, geochemical occurrences of geogenic heavy metals were identified through statistical processing of the national geochemical map data and evaluation of geochemical characteristics of regions with high geoaccumulation indices. Cobalt, Cr, Cu, Ni, Pb, V, and Zn were targeted for which the national geochemical maps were prepared, and Co, Cr, Ni, and V derived from ultrabasic or ultramafic rocks were classified as factor 1. Copper, Pb and Zn of non-ferrous sulfide origin were classified as factor 2. In particular, enrichment of heavy metals by factor 1 occurs mainly in the serpentine distribution areas of the Chungcheong region, and there is a risk of contamination in neighboring areas. In the case of factor 2, geogenic occurrence is concerned not only in non-ferrous metal mineralization areas such as Taebacksan and Gyeongnam mineralization zones, but also in Au-Ag mineralization areas distributed nationwide.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.22-29
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• 2011

Rhodopsin is a membrane protein with seven transmembrane region which contains a retinal as its chromophore. Although there have been recently reports on various photo-biochemical features of rhodopsins by a wide range of purifying and measurement methods, there was no actual comparison related to the difference of biochemical characteristics according to their physical environment of rhodopsins. First, proteorhodopsin (PR) was found in marine proteobacteria whose function is known for pumping proton using light energy. Second one is Anabaena sensory rhodopsin (Nostoc sp.) PCC7120 (ASR) which belongs to eubacteria acts as sensory regulator since it is co-expressed with transducer 14 kDa in an operon. In this study, we applied two types of rhodopsins (PR and ASR) to various environmental conditions such as in Escherichia coli membranes, membrane in acrylamide gel, in DDM (n-dodecyl-${\beta}$-D-maltopyranoside), OG (octyl-${\beta}$-D-glucopyranoside), and reconstituted with DOPC (1,2-didecanoyl-sn-glycero-3-phosphocholine). According to the light-induced difference spectroscopy, rhodopsins in 0.02% DDM clearly showed photointermediates like M, and O states which respond to the different wavelengths, respectively and showed the best signal/noise ratio. The laser-induced difference spectra showed the fast formation and decay rate of photointermediates in the DDM solubilized samples than gel encapsulated rhodopsin. Each of rhodopsins seemed to be adapted to its surrounding environment.

• Journal of the Mineralogical Society of Korea
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• v.31 no.2
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• pp.87-101
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• 2018

The Manjang deposit developed in the Hwajeonri formation of the Okcheon metamorphic belt consists of the Central and Main orebodies of Cu-bearing hydrothermal vein type and the Western orebody of Fe-skarn type. This study focuses on the Cu mineralization of the Central and Main orebodies to compare with the genetic environments of the Western orebody previously studied. The Central orebody produced pyrrhotite and chalcopyrite as major ore minerals with vein texture, while the Main orebody contains pyrite, arsenopyrite, and chalcopyrite as major ore minerals with vein, massive, and brecciated texture. Sphalerite, galena, magnetite, ilmenite, rutile, cassiterite, wolframite, and stannite are also accompanied. Local occurrence of skarn is dominated by grossular and hedenbergite, reflecting the reduced condition of the skarnization. Geothermometries of sphalerite-stannite in the Central orebody and arsenopyrite-pyrite in the Main orebody indicate the formation temperature of $204-263^{\circ}C$ and $383-415^{\circ}C$, respectively. Sulfur fugacity of $10^{-6}-10^{-7}atm$. in the Main orebody decreased toward the Central orebody. Sulfur isotope compositions of sulfide minerals from the Central and Main orebodies are 4.6-7.9‰ and 4.3-7.0‰, respectively, reflecting magmatic origin with slight influence by host rock. Considering ore mineralogy, texture as well as physicochemical conditions, the Main and Central orebodies of hydrothermal Cu mineralization reflect the characteristics of proximal and distal type ore mineralization, respectively, related to hidden igneous rocks, and they were generated under different hydrothermal systems from the Fe-skarn Western orebody.

• Journal of Environmental Policy
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• v.4 no.1
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• pp.1-19
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• 2005

On January 1, 2005, the Special Act on Metropolitan Air Quality Improvement, known as the Blue Sky 21 Program, entered into force. This Special Act is aimed at reducing the annual average concentrations of $PM_{10}$ and $NO_2$ to $40{\mu}g/m^3$ and 22ppb, respectively, from their current levels of $76{\mu}g/m^3$ and 36ppb, within the next 10 years. While the main focus of the Act is to reduce $PM_{10}$ and $NO_2$ emissions, the government also anticipates that these reductions would lessen high ozone occurrences and improve visibility. However, reducing local PM emissions would not decrease $PM_{10}$ concentrations as much as expected since other significant sources, such as continental inflow and/or secondary formation from photochemical reactions, exist. This is corroborated by the fact that $PM_{10}$ in the greater Seoul Metropolitan area during the ozone season is mostly in the form of $PM_{2.5}$, which is secondarily formed on a regional scale. Furthermore, many modeling results indicate so-called '$NO_x$ disbenefits,' referring to the fostering of an increase in ozone concentrations from a decrease in $NO_x$ emissions, over an extensive area. In this paper, the current status of air quality in the Seoul Metropolitan area is reviewed, and several other issues, including the effect of long-range transport, photochemical characteristics, and tasks for successful implementation of the Special Act are discussed.