• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.35-44
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• 2000

It was numerically studied that NOx emission characteristics of confined $CH_{4}$ jet flames with the variation of the diameter of inner fuel nozzle, the flow rate of $CH_{4}$ and equivalence ratio. Parabolic type equations were adopted in the calculation and GRI-2.1I mechanism was used for the chemical reaction. NOx emission index (EINOx) was introduced to evaluate NOx emission quantitatively in parametrically varied flames and the contribution of Thermal and Prompt NO mechanism was discussed. The results showed that Total EINOx varied sensitively with the variation of the flow rate of$CH_{4}$ but it was not sensitive to the variation of the diameter of inner fuel nozzle. Thermal EINOx showed the similar tendency to total EINOx and Prompt EINOx showed insensitivity to the variation of the diameter of inner fuel nozzle and the flow rate of $CH_{4}$.

• Economic and Environmental Geology
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• v.6 no.2
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• pp.115-122
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• 1973

The writer intended to observe the relative mobility of elements in weathering process of granite, on the outskirts of IRI city at Jeollabukdo KOREA. He analysed fresh granites and weathered ones of Hwang-Dung granite mass and had following conclusions by the triangular diagrams and the oxidized variation diagrams of the analysis. 1) The increasing phenomena of $H_2O$ observed clearly in early and late stage of weathering processes. 2) Granites was weathered by physical weathering in early stage, and it was weathered by chemical weathering in late stage. 3) The ratio of $FeO/Fe_2O_3$, FeO/MgO, and $SiO_2/Al_2O_3$ decreased uniformly from early to late stage of weathering processes. 4) It was proved that weathering potential of granite was larger than that of basaltic rock. 5) The order of mobility in major elements was Ca, Na, K>Si>Mg>Fe, Al.

• Journal of Environmental Science International
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• v.11 no.6
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• pp.529-535
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• 2002

Efffcts of physico-chemical factors on the zonation and vertical distribution of benthic microalgal communities in the tidal flats of Youngkwang and Canaiin, Korea, were studied. Concentrations of nutrients were low throughout the study period. A 38 species of benthic microaigae was identified. Most of the algae were pennate diatoms with small size. Cell numbers at silty sediments were higher than sandy sediments, and showed high patchy distribution. Zonal distributions of benthic microalgae showed higher variation from silty sediment than sandy sediments. Benthic microalgae showed vertical migration within the upper few mm of sediment with periodicity closely related to tidal cycles. Maximum cells were observed from 0 mm depth both sandy and silty sediments. Cells of benthic microalgae in the 1 - 2 mm depth decreased after desiccation of sediments. The variation of cells was higher at sandy sediments than silty sediments. Cell numbers of benthic microalgae showed no positive relationships with pH and nutrinets except NH$_4$-N.

• Journal of the Korean Chemical Society
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• v.22 no.2
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• pp.62-66
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• 1978

The polarizability tensor components for $NH_3,\;BH_3,\;HCN,\;C_2H_4,\;PO,\;PO^-$ and CO molecules are calculated by the variation method. The parallel components of the polarizability are closer to the experimental values than those of CNDO/2, MINDO/1 and MINDO/2, but the perpendicuar components of the polarizability are not closer to the experimental values than those of the other methods.

• Journal of the Semiconductor & Display Technology
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• v.4 no.3 s.12
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• pp.1-4
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• 2005

Silicon oxynitride films were deposited using ammonia as a nitrogen source via PECVD (plasma enhanced chemical vapor deposition) to study the physical properties of the films. Silane and nitrous oxide were used as silicon and oxygen sources, respectively. The composition of the silicon oxynitride films was well controlled by changing the ratios of the sources and confirmed by XPS. The silicon oxynitride films with high oxygen content showed bigger compressive stress and less refractive index, while the values of surface roughness were around 1 nm, irrespective of the variation of the source ratios.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.1
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• pp.11-17
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• 1997

The treatment performances of anaerobic-aerobic activated sludge process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal efficiency of nitrogen and phosphorus compounds under experimental conditions. The average removal efficiency of total nitrogen gradually decreased as the influent total nitrogen concentration was increased. High C/N ratio of the wastewater was required for the complete removal of nitrogen. Glucose as a carbon source was more efficient than starch and the removal ability for all components become higher with the increase of the fraction of glucose.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.503-508
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• 2015

The adsorption characteristics of ammonia on MSWI bottom ash were investigated. The effect of the variation of the landfill environmental parameters including pH, anions and organic matter on the adsorption process was discussed. Results showed that the adsorption could be well described by pseudo-second-order kinetics and Langmuir model, with a maximum adsorption capacity of 156.2 mg/g. The optimum adsorption of ammonia was observed when the pH was 6.0. High level of ion and organic matter could restrict the adsorption to a low level. The above results suggested that MSWI bottom ash could affect the migration of ammonia in the landfill, which is related to the variation of the landfill circumstance.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1153-1163
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• 2005

Crown ether-based HPLC chiral stationary phases (CSPs) have been successfully utilized in the resolution of various racemic compounds containing a primary amino group. Especially, CSPs based on chiral crown ethers incorporating chiral binaphthyl unit or tartaric acid unit and based on phenolic pseudo chiral crown ethers have shown high chiral recognition efficiency. In this account paper, a review on the development of crown etherbased HPLC CSPs, their structural characteristics and applications to the resolution of racemic compounds including chiral drugs containing a primary or secondary amino group with the variation of the type and the content of mobile phase components and with the variation of the column temperature is presented.

• Journal of the Korean Chemical Society
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• v.13 no.3
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• pp.199-204
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• 1969

The distribution rate of 4f and 5f series elements in chelate and ion association extraction system was studied. Clear difference between lighter and heavier part of 4f series are observed. Trivalent Am and Cm were appeared to be grouped into the lighter part of 4f series. And also the variation of distribution ratio according to the varied temperature was studied. The variation modes of distribution ratio are different according to the extraction system. Atomic number dependence in the chelate extraction system was observed.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.11-17
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• 1992

The treatment performances of anaerobic-aerobic activated sludge Process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal efficiency of nitrogen and phosphorus compounds under experimental conditions. The average removal efficiency of total nitrogen gradually decreased as the influent total nitrogen concentration was increased. High C/N ratio of the wastewater was required for the complete removal of nitrogen. Glucose as a carbon source was more efficient than starch and the removal ability for all components become hither with the increase of the fraction of glucose.