• Journal of the Korean Professional Engineers Association
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• v.35 no.4
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• pp.29-33
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• 2002

WATER, the best known and most abundant of all chemical compounds occurring in relatively pure form on the earth"s surface . And life, the material of which organisms are made by water and protoplasm. Especially, between human life and water must be joined by human"s protoplasm, proteins, nucleic acids cells energy exchange and anothers. Therefore. health of mankind is In according to drink enough clean water and to use good water environment.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1761-1766
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• 2005

Solvolysis rates of isopropenyl chloroformate (3) in water, $D_2O$, $CH_3OD$ and in aqueous methanol, ethanol, 2,2,2-trifluoroethanol (TFE), acetone, 1,4-dioxane as well as TFE-ethanol at 10 ${^{\circ}C}$ are reported. Additional kinetic data for pure water, pure ethanol and 80%(w/w) 2,2,2-trifuoroethanol (T)-water (W) at various temperatures are also reported. These rates show the phenomena of maximum rates in specific solvents (30% (v/v) methanol-water and 20% (v/v) ethanol-water) and, variations in relative rates are small in aqueous alcohols. The kinetic data are analyzed in terms of GW correlations, steric effect, kinetic solvent isotope effects (KSIE), and a third order model based on general base catalysis (GBC). Solvolyses based on predominately stoichiometric solvation effect relative to medium solvation are proceeding in 3 and the results are remarkably similar to those for p-nitrobenzoyl chloride (4) in mechanism and reactivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.617-620
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• 1999

To reduce the consumption of chemicals and ultra pure water(UPW) in cleaning process used in device manufacturing, we proposed wet processes that use electrolytic ionized water(EIW), which is generated by electrolysis of a diluted electrolyte solution or UPW and systemically investicate the EIW\`s characteristics. EIW\`s pH values are increased in cathode chamber and decreased in anode chamber according to the electrolysis time and its varied ratio is reduced with time increasement. The variation of pH and ORP is increased accordin to the applied voltage until critical voltage. But more than that voltage, the variation is decreased because of ion\`s scattering effect. When electrolyte is added, the effects of electrolysis is increased because electrolyte acts as catalyst. But when the density of electrolyte is increased more than critical value, ion\`s flowage is obstructed and the effects of electrolysis is decreased.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.165-178
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• 1996

We investigated the role of competition in adaptation to varying water availability levels for two ecotypically-differentiated populations of Impatiens pallida found naturally in low- vs. high-water environments. In a greenhouse experiment, seedlings were grown in pure cultures at two densities (n=1 and 2 plants per pot) and in mixed cultures (n=2) under low-, medium- and high-water treatments. The two populations were shown to be genetically distinct across the range of environmental conditions in the greenhouse experiment, confirming previous findings. The two populations had similar morphological responses to density and water availability in pure cultures and mixtures, but the population from the high-water environment showed a greater growth response to high water availability than did the population from the low-water environment and the difference in growth between the two populations decreased from the high-water to low-water treatment. Relative competitive ability of two populations were compared under three different water treatments and two densities. Differential response to watering treatment and density were not reflected in a difference in relative competitive ability. Relative yield totals were significantly greater than 1 overall. The niche differentiation suggested by RYTs>1 may be responsible for the lack of differential competitive effects observed for populations in the three vatering treatments.

• Journal of the Korean Institute of Gas
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• v.8 no.3 s.24
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• pp.24-30
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• 2004

Gas hydrate formation process is studied in this paper. Natural gas was introduced into both pure water and water added anionic surfactant(promotor) at 276.65 K and 6 MPa. Gas hydrate nuclei was easily generated by instantaneous agitation. Gas hydrate film was formed on the interface of water and gas. The very thin film which was instantly covered the surface of the water, followed by generation of the clear film layer. Whiskery crystal of gas hydrate was created more actively in the water added naionic surfactant than in the pure water. Whiskery hydrate formed in the pure water looks like short and thick thread colony while the one shoes long and thin thread colony in the water added promoter.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.4
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• pp.27-34
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• 1999

An experimental study on improvement of the paper-mill wastewater treatment using the pure oxygen activated sludge process was conducted. The effects of hydraulic retention time(HRT) and BOD loading on organic removal efficiency were investigated. The BOD removal efficiencies were above 90% under all examined HRTs except for HRT of 3 hours. The increase of HRT from 3 hours to 6 hours, and to 12 hours significantly improved BOD and COD removal efficiencies, respectively. However, additional increase of HRT did not affect organic removal efficiency. F/M ratio change at fixed HRT did not affect organic removal efficiency. However, F/M ratio investigated in this study(0.11~1.98kgBOD/kgMLVSS/day) was 5 times greater in maximum than that of conventional activated sludge process, which implies that pure oxygen activated sludge process can treat wastewater with high organic strength. Under the same HRT, the volumetric BOD loading change cause no effect on organic removal efficiency also.

• Membrane Journal
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• v.24 no.5
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• pp.393-399
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• 2014

The permeation experiments were carried out to examine the separation characteristics of the modules which were piled up the disc-ring shape patterned membranes in this study. First of all, permeability of the pure water was measured for the self-made 5 shape disc filters, and varied from 0.25 to $2.24L/m^2{\cdot}hr{\cdot}bar$. The module showed the maximum pure water permeability was the maximum permeation flux, and the module showed the minimum pure water permeability was the minimum permeation flux for 0.1 wt% kaolin solution. However, all of the modules were not proportioned to the pure water permeability. Also, the backwashing was performed periodically for the module 1 in order to operate with 0.1 wt% kaolin solution for a long time. The most efficient operating condition was the 8 minute permeation and 2 minute backwashing cycle.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.9
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• pp.597-603
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• 2017

In this study, experiments were conducted on the MFB(minimum film boiling) point of highly heated vertical metal rod quenched in aqueous surfactant solution at various temperature conditions. The aqueous Triton X-100 solution(100 wppm) and pure water were used as the liquid pool. Their temperatures ranged from $77^{\circ}C$ to $100^{\circ}C$. A stainless steel vertical rod of initial center temperature of $500^{\circ}C$ was used as a test specimen. In both liquid pools, as the liquid temperature decreased, the time to reach the MFB point decreased with a parallel increase in the temperature and heat flux of the MFB point. However, over the whole present temperature range, in the aqueous Triton X-100 solution, the time to reach the MFB point was longer, while the temperature and heat flux of the MFB point were reduced when compared with pure water. Based on the present experimental data, this study proposed the empirical correlations to predict the MFB temperature of a high temperature vertical metal rod in pure water and in aqueous Triton X-100 solution.

• Membrane Journal
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• v.24 no.4
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• pp.276-284
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• 2014

In this study, a hydrophobic polyvinylidene fluoride (PVDF) membrane was modified by coating neutral hydrophilic poly(vinyl alcohol). The flux of pure water was measured and then fouling test was conducted with bovin serum albumin (BSA) as model protein foulant. As a result, the experiments showed that pure water flux was decreased but anti-fouling property was significantly enhanced. Pure water flux with increasing molecular weights of the polymer was decreased and fouling resistance was enhanced. Also, Pure water flux with increasing solution concentration was decreased and fouling resistance was enhanced. It is probably due to the increase in hydrophilicity and decrease in roughness of the membrane surface, as revealed by contact angle and AFM analysis.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.763-773
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• 2010

The removal efficiencies and a total oxygen transfer coefficient for food waste leachate(FWL) were estimated by using Jet Loop Reactor(JLR). Pure oxygen was used instead of air to improve oxygen concentration in the JLR for high total chemical oxygen demamd(TCOD) in FWL. In JLB, in order to examining the oxygen transfer characteristic, the circulation flowrate and oxygen flowrate were controlled with 7~10 L/min(1.5 L/min interval) and 0.2~0.5 L/min (0.1 L/min interval) and we experimented according to the each condition. As a result, Oxygen uptake rate(OUR) and oxygen transfer rate could be maximized than the oxygen flowrate to increase the circulation flowrate. In addition, it determined that JLR using the pure oxygen which can obtain the greatest oxygen transfer rate as it was the high-concentration organic wastewater like the food waste leachate through the continuous experiment was appropriate.