• Corrosion Science and Technology
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• 제18권4호
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• pp.129-137
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• 2019

CFRP (Carbon Fiber Reinforced Plastics) is composed of carbon fiber and plastic resin, and is approximately 20 - 50% lighter than metallic materials. CFRP has a low density, higher specific stiffness, specific strength, and high corrosion resistance. Because of these excellent properties, which meet various regulation conditions needed in the industrial fields, CFRP has been widely used in many industries including aviation and ship building. However, CFRP reveals water absorption in water immersion or high humidity environments, and water absorption occurs in an epoxy not carbon fiber, and can be facilitated by higher temperature. Since these properties can induce volume expansion inside CFRP and change the internal stress state and degrade the chemical bond between the fiber and the matrix, the mechanical properties including bond strength may be lowered. This study focused on the effects of NaCl concentration (0.01 - 1% NaCl) and solution temperature ($30-75^{\circ}C$) on the galvanic corrosion between CFRP and A516Gr.55 carbon steel. When NaCl concentration increases 10 times, corrosion rate of a specimen was not affected, but that of galvanic coupled carbon steel increased by 46.9% average. However, when solution temperature increases $10^{\circ}C$, average corrosion rate increased approximately 22%, regardless of single or galvanic coupled specimen.

• 한국염색가공학회지
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• 제3권2호
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• pp.34-42
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• 1991

The effects of electrolyte on dyeing properties of cotton fiber with Congo Red have been studied at 90, 70 and $40^{\circ}C$. Each dyeing carried into an infinite bath with $1\times10^{-4}$ mol/l of Congo Red and with various concentration of electrolytes. The results obtained from this study were as follow; 1. The equilibrium adsorption of dye $(C_\infty)$ values decreased with increasing dyeing temperature, $C_\infty$ values increased in the order KCl>NaCl>LiCl. 2. The values of apparent diffusion coefficients $(D_a)$ increased with increasing dyeing temperature, but $D_a$ values decreased in the order KCl$D_a$ values decreased with increasing electrolyte concentration. 4. Effect of electrolytes decreased with increasing dyeing temperature. 5. The values of standard affinities of dyeing $(-\triangle\mu^{\circ})$, the standard heats of dyeing $(-\triangleH^{\circ})$, and the standard entropies $(-\triangleS^{\circ})$, increased in the order KCl>NaCl>LiCl. 6. Equilibrium adsorption isotherm curve were Freundlich type, and in the Equation y=a.x$^{n}$ , the values of a and n increased in the order KCl>NaCl>LiCl. 7. The value of $-\triangle\mu^{\circ}$, $-\triangleH^{\circ}$, and $-\triangleS^{\circ}$, decreased with increasing electrolyte concentration.

• 한국식품과학회지
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• 제34권2호
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• pp.283-289
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• 2002

속성 발효 및 기능성 멸치액젓의 제조에 사용할 수 있는 미생물 starter의 개발을 목적으로 1, 3 그리고 5년 숙성한 멸치액젓으로부터 단백질 분해활성 및 혈전 용해 활성 우수한 균주를 분리, 동정하였고, 분리균주들 중 단백질 분해활성과 혈전 용해 활성 가장 강하였던 B. subtilis JM-3의 최적 성장 조건과 단백질 분해효소 및 혈전 용해효소 최적 생산조건들을 조사하였으며, 그 결과를 요약하면 다음과 같다. 1, 3 그리고 5년 숙성한 멸치액젓으로부터 단백질 분해활성과 혈전 용해 활성 가지는 3균주를 분리하였으며, 분리균주 JM-1, JM-2 그리고 JM-3는 모두 Bacillus subtilis로 동정되었다. 분리균주들 중 가장 강력한 단백질 분해활성과 혈전 용해 활성 나타낸 B. subtilis JM-3의 최적 성장조건은 $40^{\circ}C$, pH 5.0 그리고 NaCl를 첨가하지 않았을 때 성장이 가장 좋은 것으로 나타났다. B. subtilis JM-3의 단백질 분해효소 및 혈전 용해효소 최적 생산 조건은 최적 성장 조건과 일치하는 것으로 나타났다. 또한 멸치액젓의 일반적인 염농도인 NaCl 20% 첨가구에서도 식염 무첨가구의 약 60%의 활성을 나타내어 B. subtilis JM-3의 멸치액젓의 starter로서의 충분한 이용 가능성을 나타내었다.

• 한국환경과학회지
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• 제25권7호
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• pp.905-916
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• 2016

The characteristics of phenol removal and $UV_{254}$ matters variance were investigated and compared by the variation of operating factors (NaCl concentration, air flow rate, initial phenol concentration) in electrochemical reaction (ER) and dielectric barrier discharge plasma reaction (DBDPR), respectively. The phenol removal rate was shown as $1^{st}$ order both in ER and DBDPR. Also, the absorbance of $UV_{254}$ matters which means aromatic intermediates was analyzed to investigate the complete phenol degradation process. In ER, the phenol degradation and aromatic intermediates production rates increased by the increase of NaCl concentration. However, in DBDPR, the variation of NaCl concentration had no effect on the degradation of phenol and $UV_{254}$ matters. Air flow rate had a little effect on the removal of phenol and the variation of $UV_{254}$ matters in ER. The phenol removal rate in ER was a little higher than that in DBDPR. The produced $H_2O_2$ and $O_3$ amounts in ER were 2 times and 10 times higher than those in DBDPR. The chlorine intermediates ($ClO_2$ and free chlorine) were produced in ER, however, they were not produced in DBDPR.

• 대한화학회지
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• 제43권1호
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• pp.36-41
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• 1999

Mercaptoacetic acid를 이용하여 흡착벗김 전압전류법으로 미량의 게르마늄을 정량하는 방법을 연구하였다. 이때 지지전해질은 0.25 M NaCl 용액(pH 6.0)을 사용하였고, mercaptoacetic acid의 농도는 $5.0{\times}10^{-6}M$이 되도록 조절하여 실험하였다. Ge(IV)-Mercaptoacetic acid 착물의 봉우리 전위는 -1.402V vs. Ag/AgCl에서 나타났다. 착물의 봉우리 전위에 미치는 NaCl의 농도, mercaptoacetic acid의 농도, 축적 시간등에 대하여 조사하였다. 또한, Amberlite IRC-718 킬레이트 수지를 다른 이온들로 부터 Ge(IV)을 분리하는데 적용하였다.

• Preventive Nutrition and Food Science
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• 제2권1호
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• pp.1-5
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• 1997

Solution Properties of polyelectrolytic biopolymers such as chitosen, pectin, alginate and etc. are significantly influenced by molecular weight and salt concentrations. The effect of NaCI concentration on the hydrodynamic properties of chitosan in dilute region was investigated for chitosans of varying molecular weight. Intrinsic vicosity([η]) of citosans with 5 different molecular weight was determined by glass capillary viscometer, and the viscosity average molecular weight was calculated using Mark-Houwink equation. Intrinsic viscosity decreased with increasing NaCI concentration for all chitosan samples, and it was proportional to the logarithmic NaCI concentration, i.e.,[η]∝log{TEX}$(C_{NaCl})^{$\alpha$}${/TEX}. Decreasing trend of[η] with NaCI concentration became more pronounced with increasing molecular weight. It was also found that the a values, indicating {TEX}$C_{NaCl}${/TEX} dependence of[η], were linearly correlated with the logarithmic molecular weight({TEX}$R^{2}${/TEX}=0.980). The chain stiffness parameters(B) were calculated by B=S./{TEX}$([η]_{0.1})^{1.32}${/TEX}, in which S was obtained from slope of [η] va {TEX}$I^{-1/2}${/TEX}. The B values of chitosan samples were determined to be 0.113~0071 with a average of 0.09.

• 한국환경과학회지
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• 제26권5호
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• pp.563-572
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• 2017

The Electrocoagulation-Flotation (ECF) process has great potential in wastewater treatment. ECF technology is effective in the removal of colloidal particles, oil-water emulsion, organic pollutants such as microalgae, and heavy metals. Numerous studies have been conducted on ECF; however, many of them used a conventional plate-type aluminum anode. In this study, we determined the effect of changing operational parameters such as power supply time, applied current, NaCl concentration, and pH on the turbidity removal efficiency of kaoline. We also determined the effects of different electrolyte types (NaCl, $MgSO_4$, $CaCl_2$, $Na_2SO_4$, and tap water), as well as the differences caused by using a plate-type and mesh-type aluminum anode, on the turbidity removal efficiency. The results showed that the optimal values of ECF time, applied current, NaCl concentration, and pH were 5 min, 0.35 A, 0.4 g/L NaCl in distilled water, and pH 7, respectively. The results also revealed that the turbidity removal efficiency of kaoline in different electrolytes decreased in the following sequence, given the same conductivity: tap water > $CaCl_2$ > $MgSO_4$ > NaCl > $Na_2SO_4$. The turbidity removal efficiency of the mesh-type aluminum anode was significantly greater than the plate-type aluminum anode.

• 한국수정란이식학회지
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• 제15권2호
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• pp.191-196
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• 2000

the present study was carried out to develop a completely defined culture system and determine if high NaCl concentrations in defined (PVA added) or semi-defined (BSA added) medium is toxic to bovine embryos. Oocytes from slaughterhouse ovaries were matured and fertilized in vitro. After 30 h of insemination, only 2-cell stage embryos were selected and cultured for this experiment. The culture media used were as follows : TLP(114 mM of NaCl) + BSA (3 mg/ml), TLP + PVA (1 mg/ml), mTLP(96 mM of NaCl) + BSA, mTLP + PVA. Six to ten embryos were placed into a 30$\mu$1 drop of each medium and the embryos were examined at 10 day post-insemination without medium renewal. The experiment was replicated 4 times. All data were analyzed by chi-square. There were no significant differences among TLP-BSA, mTLP-BSA and mTLP-PVA in blastocyst development (21.6, 17.2 and 20.2%), respectively. Also, no differences were obtained in hatching rates (11.7, 9.9 and 12.2%), respecitively. However, there were significant differences between TLP-PVA (1.7% and 0.6%) and other group in blastocyst formation and hatching rates, respectively (p<0.01). Development of in vitro produced embryos cultured in BSA containing medium was not affected by high NaCl concentration, but in the completely defined medium, embryonic development was highly affected by NaCl. This study shows that reduced NaCl concentration in completely defined medium is beneficial for development of bovine pre-implantation embryos in vitro.

• 농약과학회지
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• 제12권4호
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• pp.368-374
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• 2008

길항력이 있는 그람음성균들의 생물적 방제제로 성공적인 개발은 균의 건조와 저장시의 낮은 생존을 때문에 건조제형으로 만드는 것은 제한되어있다. 그람음성균의 배양시 높은 염(NaCl)의 첨가는 삼투압 조절제인 osmolyte의 생성을 유도하여 건조 시 생존율을 높인다고 알려져 있다. 그람음성의 길항력을 내는 비병원성 Erwinia carotovora subsp. carotovora(Ecc) 9-3의 건조와 저장시의 염의 영향에 관해 연구하였다. Ecc 9-3의 생장률은 0.5 M의 염이 첨가되어 있는 배지에서 큰 차이가 없었지만 0.7 M의 염이 첨가된 배지에서는 급격하게 낮아진 것을 확인하였다. 건조와 저장시의 생존율은 0.5 M의 염을 넣은 배지가 염을 넣지 않은 배지보다 상온건조와 동결건조에서 각각 2배 그리고 3배의 높은 생존율을 얻었다. 건조 후 저장에서도 역시 염이 높을수록 Ecc 9-3의 생존율이 더 높았다. 그리고 상온건조와 동결건조 모두 $4^{\circ}C$에 저장하였을 때 생존율에 큰 차이가 없었다. 그러나 생존율은 $27^{\circ}C$, $37^{\circ}C$에 저장하였을 때 염의 농도가 높을수록 생존율이 증가하였다. 첨가제 실험에서는 lactose가 동결건조와 상온건조 모두에 영향을 주었고 dextrin은 상온건조에 큰 영향을 주었다.

• 자원환경지질
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• 제46권1호
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• pp.21-28
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• 2013

저항성 황화광물 정광으로부터 금 용출을 최적화시키기 위하여 HCl-NaClO-$FeCl_3$ 용액과 다양한 변수를 유일광산 소성정광에 적용하였다. 유일광산의 gold는 용출시키기 어려운 비가시성 gold로 산출되었다. 다양한 변수를 이용하여 용출실험을 수행한 결과, 소성온도 $550^{\circ}C$, 첨가량 2.0 M, 광액농도 1.0% 그리고 용출온도 $70^{\circ}C$에서 최대의 gold 용출율을 얻었다. HCl-NaClO-$FeCl_3$ 용액은 황화광물 정광으로부터 금과 은을 친환경적으로 용출시킬 수 있는 시안 대체 용매제 일 것으로 사료된다.