• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2000년도 추계학술대회 논문집(Proceeding of the KOSME 2000 Autumn Annual Meeting)
• /
• pp.1-6
• /
• 2000

This paper was studied on the crevice corrosion behavior of SS 400 in marine environment. In 0%, 2%, 3.5%, 5% NaCl solution, the aspect of the crevice corrosion and polarization behavior under the crevice corrosion was investigated. And Weight loss rate of SS 400 with crevice and non-crevice was measured according to the NaCl concentration. The main results obtained are as follows : 1) Under crevice corrosion, the corrosion potential become less noble as the concentration of NaCl solution increased. 2) The current density under open circuit potential was high drained as concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, the current density was low drained. 3) The weight loss rate of SS400 was increased as concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, that of SS400 was decreased.

• 공업화학
• /
• 제34권1호
• /
• pp.64-68
• /
• 2023

전기투석에서 농축 공정은 전기 에너지를 이용하여 전해질 수용액 상의 이온의 농도를 증가시키는 기술로, 이온교환막에서 일어나는 이온과 물 분자의 전달 현상에 대해 많은 연구들이 진행되고 있다. 본 연구에서는 전기투석 시스템에서 고농도 전해질 수용액의 전기 삼투에 의한 농축 현상에 대한 실험을 통해 한계 농축 현상에 대한 변수를 분석한다. 두 가지 전해질 수용액(NaCl 2M / 4M)에 대해 이온과 물 분자의 투과량을 측정해 전기 삼투 현상을 분석하였고, 농축조 대비 탈염조의 부피 비에 따른 한계 농축 현상을 관찰하였다. 실험 결과, 전해질 수용액의 농도가 높을수록 전기 삼투가 감소하였고, 부피 비가 클수록 탈염수의 농도가 높게 유지되기 때문에 한계 농축 농도가 증가하고 비에너지 소모가 감소됨을 확인하였다.

• 한국재료학회지
• /
• 제32권4호
• /
• pp.230-236
• /
• 2022

The formation behavior of a passive state film on the surface of STS304 in electrolytic solution was analyzed to determine its metallic ion composition. The properties of passive state films vary depending on the Fe and Cr ions in the electrolytic solution. It was observed that the passive state film surface became flat and glossy as the concentration of Fe and Cr ions in the electrolytic solution increased. The corrosion resistance property of the passive state film was proportional to the amount of Fe and Cr in the electrolytic solution. An initial passive state film with high Fe concentration was formed on the surface of STS304 during early electrolytic polishing. Osmotic pressure of Fe ions occurs between the passive state film and electrolytic solution due to the Fe ion concentration gradient. The Fe in the passive state film is dissolved into the electrolyte, and Cr fills up the Fe ion vacancies. As a result, a good corrosion-resistant floating film was formed. The more Fe ions in the electrolytic solution, the faster the film is formed, and as a result, a flat passive state film containing a large amount of Cr can be formed.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
• /
• pp.131-136
• /
• 1997

It is well known that concrete is typical porous material. We pay attention to Hansen's idea that concrete may be expected to act as semi-permeable membrane, and report the effect of concentration of solution and temperature on water flux in forward osmosis. In order to measuring volume of water flux from distilled water to solution of sodium chloride through hardened cement paste, specially designed apparatus was constructed, and the following result were obtained: (1) hardened cement paste acts as semi-permeable membrane, consequently, water flux in forward osmosis may occur. (2) Rate of water flux is proportion to concentration of dilute solution, and this suggests hardened cement paste is agreeable to the theory of membrane. (3) Effect of temperature on water flux is agreeable to Arrehenius equation and is great.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제5권1호
• /
• pp.65-70
• /
• 2000

An approximated analytical solution of mathematical model for the three phase fluidized bed bioreactor (TFBBR) was proposed using the linearization technique to describe oxygen utilization rate in wastewater treatment. The validation of the model was done in comparison with the experimental results. Satisfactory agreement was obtained in the comparison of approximated analytical solution and numerical solution in the oxygen concentration profile of a TFBBR. The approximated solutions for three modes of the liquid phase flow were compared. The proposed model was able to predict the biomass concentration, dissolved oxygen concentration the height of efficient column, and the removal efficiency.

• 한국항해항만학회지
• /
• 제27권6호
• /
• pp.669-675
• /
• 2003

Using a SQUID magnetometer, the diamagnetic susceptibility of NaCl aqueous solution was measured with high accuracy in a magnetic field of up to 6 Tat 25$\pm0.05^{\circ}C$. The NaCl concentrations adopted in this experiment were 0 (water), 7.5, 15, 23, 26.2, 26.6 and 100% (crystal) with the concentration error of $\pm$0.04%. Experimental data was compared with the calculated value of susceptibility derived from dependence of the vapor pressure on NaCl concentration As a result, our measured value was almost in accordance with the calculated value. It was found that the diamagnetic susceptibility shows a decrease of approximately 10% within the saturated concentration (26.2%) and that the susceptibility is one of the effective cause for the concentration dependence in the gas-liquid interface deformation of the NaCl solution.

• Journal of Oral Medicine and Pain
• /
• 제5권1호
• /
• pp.1-4
• /
• 1980

Caries free anterior teeth were rinsed for 10 minutes with 1%, 5% sodium fluoride and 1% stannous fluoride solution three times a day for the period of experiment. And the author measured the concentration of enamel fluoride by means of Mc Cann's Technique. And the results were as follows : 1. There were little difference of enamel fluoride concentration between the teeth treated with 5% sodium fluoride solution. 2. The enamel fluoride concentration shows a tendency of direct proportion in lower concentration of fluoride solution for the period of 10 days. 3. The Enamel fluoride concentration in the group treated with stannous fluoride solution reveals acute elevation in the 5th day of experiment but the trend was not direct proportional in the 10th day of experiment.

• 생물환경조절학회지
• /
• 제15권1호
• /
• pp.53-68
• /
• 2006

This experiment was conducted to investigate the effects of diurnal alternation of nutrient solution salinity on growth and fruit quality of tomatoes (Lycoperisicon esculentum cv. 'House momotaro') hydroponically grown in root intercept bag-NFT (RIB-NFT) system. Plant height was the lowest in the high concentration during daytime (6/1 $dS\;m^{-1}$, day/night). Yield was very high in the concentration of 1/1 $dS\;m^{-1}$, it decreased with increasing the concentration of nutrient Yield was higher at low concentration (4/1 $dS\;m^{-1}$) at nighttime compared to the same concentration (4/4 $dS m^{-1}$) at daytime and nighttime, and the reverse (1/4 $dS\;m^{-1}$) was similar to the control (perlite culture). Yield was greatly reduced by higher concentration at daytime than nighttime, and the decrease was alleviated by lower concentration at nighttime. With increasing the concentration of nutrient solution during daytime, sugar content of tomato fruit was increased, but yield was decreased. In the other experiment, tomato plants were hydropoically cultured in NFT system diurnally alternated between Aichi's solution and $Ca(NO_3)_2$ solution. $Ca(NO_3)_2$ solution was supplied for 4 hours from 10:00 to 14:00 at daytime and from 22:00 to 2:00 at nighttime, respectively, and Aichi's solution was supplied for the time except the 4 hours. Ca content of leaves and sugar content of fruit were increased by supplying $Ca(NO_3)_2$ solution at daytime compared to nighttime, but plant growth was greatly suppressed by supplying $Ca(NO_3)_2$ solution with the concentration of 4 $dS\;m^{-1}(4/4^{Ca}\;dS\;m^{-1})$ at nighttime.

• KSBB Journal
• /
• 제11권6호
• /
• pp.630-635
• /
• 1996

IgG와 알부민이 고스트 적혈구의 분산하에서 적 혈구의 세포막에 흡착되었다. 용액중 IgG의 농도가 0 O.1mg/mL일 때, 고스트 적혈구의 부피비가 5% 에 서 45%로 증가함에 따라 흡착으로 인한 용액중의 IgG의 농도감소는 14%에서 45%로 증가하였고, h hardened 고스트 척혈구 분산시가 고스트 적혈구 분산시보다 더 많은 단백질이 흡착되었다. 용액중 알부민의 농도가 0.075mg/mL일 때, 고스트 적헐구 의 부피가 5%에셔 70%로 증가함에 따라 용액중의 얄부민의 농도감소는 12% 에서 47%로 증가하였다. 흡착시간에 대한 IgG의 농도변화를 측정한 결과 단 백질의 흡착은 빠른 속도로 일어남을 알 수 있었고, 적혈구당 흡착된 단백질 분자수를 계산한 결과 용액 내 적혈구의 수가 증가할수록 적혈구당 흡착된 분자 수는 감소하였다.

• Journal of the Korean Wood Science and Technology
• /
• 제44권5호
• /
• pp.743-749
• /
• 2016

균일한 품질의 방부처리 목재 생산을 위해서는 방부약액의 농도관리가 필요하다. 아직까지 목재방부처리 현장에서 농도관리를 위하여 간편하게 방부약액의 농도를 측정할 수 있는 방법은 개발되어 있지 않다. 본 연구에서는 ACQ 목재방부제를 대상으로 비교적 손쉽게 측정할 수 있는 탁도를 이용하여 농도를 예측할 수 있는 방법을 검토하였다. 탁도가 현저하게 작은 알칼리성의 ACQ 약액에 20%의 인산 용액을 첨가하면 백색의 현탁 물질이 생성되며 탁도가 증가한다. 인산 용액의 최적 첨가량은 약액의 탁도가 최고치에 도달하는 pH 7 수준이며, 첨가량이 많아지면 약액의 산성화와 함께 탁도가 급격하게 떨어지고 약액은 투명해진다. ACQ 약액의 농도와 탁도 간에는 정(正)의 상관을 가지며 고도의 유의성이 인정되었다. 농도와 탁도로부터 유도된 회귀방정식을 사용하여 산출한 현장 채취 약액의 예측 농도 값과 적정법으로 측정한 실측 농도 값 간의 농도 차이에는 t 검정 결과, 유의성이 인정되지 않았다. 따라서 탁도와 회귀방정식을 이용하여 ACQ 현장 약액의 농도 관리가 가능할 것으로 예상된다.