• 기술사
• /
• 제35권4호
• /
• pp.29-33
• /
• 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
• /
• 제26권11호
• /
• pp.1761-1766
• /
• 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.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 추계학술대회 논문집
• /
• pp.617-620
• /
• 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
• /
• 제19권2호
• /
• pp.165-178
• /
• 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.

• 한국가스학회지
• /
• 제8권3호
• /
• pp.24-30
• /
• 2004

본 연구에서는 개선된 view cell 실험 장치를 통하여 가스 하이드레이트 생성 과정을 관찰하고 이의 동특성을 고찰하였다. 순수한 물과 촉진제로 음이온계 계면활성제를 미량 첨가한 물에 천연가스를 넣어 가스 하이드레이트를 생성 과정을 관찰하였다. 본 실험에서 사용한 276.65 K, 6 MPa 조건 상태에서는 충분한 지체 지연 시간이후 물에 순간 교반을 줌으로써 형성자 생성을 쉽게 유도할 수 있었다. 가스 하이드레이트 필름의 생성은 정적상태에서 가스와 접촉된 물의 표면에 생성되었다. 이는 육안으로 구분하기 어려운 매우 얇은 막이 수초 안에 물의 표면 전체를 덮는 선행과정과 이후 다시 육안관찰이 쉬운 필름층이 재생성되었다. 순수한 물에는 짧고 굵은 섬유 다발의 형태로 끝 부분이 둥글게 말려서 결정이 형성된 모습인 반면 촉진제를 넣은 경우 작은 섬유 다발 형태로 길게 생성되었고 다른 다발과 접촉되어 엉킨 결정 상상을 보였다.

• 상하수도학회지
• /
• 제13권4호
• /
• pp.27-34
• /
• 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.

• 멤브레인
• /
• 제24권5호
• /
• pp.393-399
• /
• 2014

본 연구에서는 디스크 링 형태에 패터닝된 박막을 적층시킨 모듈의 분리특성을 규명하고자 투과실험을 수행하였다. 먼저, 본 연구에서 자체 제작한 5가지 형태의 디스크 필터의 순수 투과도를 측정하였으며 그 값은 0.25 내지 $2.24L/m^2{\cdot}hr{\cdot}bar$이었다. 0.1 wt% 카올린 수용액을 투과시키면 순수 투과율이 가장 높은 모듈의 투과유속이 가장 높았고, 순수 투과율이 가장 낮았던 모듈의 카올린 투과유속이 가장 낮게 나타났다. 그러나 모든 모듈의 카올린 투과유속이 순수 투과율에 비례하지는 않았다. 또한 0.1 wt% 수용액으로 장시간 운전하기 위하여 디스크 필터 모듈 1에 주기적으로 역세척을 실시하였으며 가장 효율적인 운전조건은 투과시간 8분, 역세척 2분 주기임을 확인하였다.

• 대한기계학회논문집B
• /
• 제41권9호
• /
• pp.597-603
• /
• 2017

다양한 온도 조건의 계면활성제 수용액 내에서 급속 냉각되는 고온 수직 금속봉의 최소막비등점에 대한 실험을 수행하였다. 액체로는 Triton X-100 수용액(100 wppm)과 순수(pure water)를 이용하였고, 액체의 온도는 $77^{\circ}C{\sim}100^{\circ}C$ 영역이었다. 고체 시편으로는 시편 중심의 초기 온도가 $500^{\circ}C$인 스테인레스 스틸(stainless steel) 수직봉을 이용하였다. Triton X-100 수용액과 순수에서, 액체의 온도가 감소함에 따라 최소막비등점의 도달시간은 감소하였고, 온도 및 열유속은 증가하였다. 한편, 본 실험 온도 영역에서, Triton X-100 수용액의 경우가 순수의 경우보다 최소막비등점의 도달시간은 길었고, 온도 및 열유속은 감소하는 경향을 나타냈다. 본 실험데이터를 토대로 고온 수직 금속봉에 대해서 Triton X-100 수용액과 순수에서의 최소막비등 온도에 대한 실험식을 제안하였다.

• 멤브레인
• /
• 제24권4호
• /
• pp.276-284
• /
• 2014

본 연구에서는 소수성 PVDF막 표면에 중성 친수성 고분자인 Poly(vinyl alcohol) (PVA)를 코팅한 후 순수 투과도를 측정하고 대표적인 단백질 오염물질인 bovin serum albumin (BSA)에 대하여 파울링 실험을 수행하였다. BSA 용액 20 ppm 조건에서 파울링 실험을 수행한 결과, 코팅 전 막에 비하여 순수 투과도는 감소하였지만 내오염성은 현저히 증가됨을 알 수 있었다. 코팅된 PVA의 분자량이 커질수록 순수 투과도는 감소하였으나, 내오염성이 증가하는 경향을 보였다. 또한, 코팅된 PVA의 농도가 높아질수록 순수 투과도는 감소하였고, 내오염성이 증가하였다. 이는 접촉각과 AFM 측정 결과와 관련하여 코팅 후 막 표면에 친수성의 증가와 거칠기가 감소했기 때문으로 여겨진다.

• 상하수도학회지
• /
• 제24권6호
• /
• pp.763-773
• /
• 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.