• Advances in concrete construction
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• 제4권4호
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• pp.305-317
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• 2016

Porous materials such as concrete could be subjected to aggressive ions transport. Durability of cement paste is extremely depended on water and ions penetration into its interior sections. These ions transport could lead different damages depending on reactivity of ions, their concentrations and diffusion coefficients. In this paper, chloride diffusion process in cement hydrates is simulated at atomistic scale using molecular dynamics. Most important phase of cement hydrates is calcium silicate hydrate (C-S-H). Tobermorite, one of the most famous crystal analogues of C-S-H, is used as substrate in the simulation model. To conduct simulation, a nanopore is considered in the middle of simulation cell to place water molecules and aggressive ions. Different chloride salts are considered in models to find out which one is better for calculation of the transport properties. Diffusion coefficients of water molecules and chloride ions are calculated and validated with existing analytical and experimental works. There are relatively good agreements among simulation outputs and experimental results.

• 한국대기환경학회지
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• 제2권3호
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• pp.27-33
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• 1986

Atmospheric particulate matter (A. P. M.) was collected and size-fractionated by an Andersen high-volume air sampler over 15 month period from Jan. 1985 to Feb. 1986 in Seoul. The concentration of chloride, nitrate and sulfate were extracted in an ultrasonic bath and were analyzed by ion chromatography. The annual arithmetical mean of A. P. M. was 128.54 $\mug/m^3$. The concentration of anions were 2.88 $\mug/m^3$ for chloride, 3.86$\mug/m^3$ for nitrate, and 25.44$\mug/m^3$ for sulfate. The content of A. P. M. was lowest in the particle size range 1.1 $\sim 3.3\mum$ and increased as the particle size increased or decreased. And the anions exhibited a seasonal variation in the isize distribution. The contents of anions were higher in winter than summer. Ther ratio of fine particles to the total particles defined by F/T for chloride, nitrate and sulfate. The F\ulcornerT of these anion generally decrease with increasing air temperature. This tendency was prevalent in the chloride and nitrate.

• 공업화학
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• 제9권7호
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• pp.968-973
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• 1998

양이온성 계면활성제인 cetylpyridinium chloride(CPC)와 비이온성 계면활성제인 Triton X-100(TX-100)의 혼합계면활성제에 염(KCl과 $Na_2CO_3$)과 부탄올 이성질체(tert-부탄올, iso-부탄올과 n-부탄올)를 첨가하였을 때 변화되는 임계미셀농도값($CMC^*$)을 UV 분광광도법으로 측정하였다. 이들 $CMC^*$값들로부터 여러 가지 열역학적 함수값들을 유사상태분리모델(pseudo-phase separation model)을 이용한 식에 의해 계산하였으며 그 값들을 상호 비교하였다. 그 결과 염 및 부탄올 이성질체들을 첨가하였을 때 CPC/TX-100 혼합계면활성제의 미셀화는 순수 물에서의 경우보다 열역학적 함수값($X_1$, $\beta$, ${\gamma}i$, $ai^M$, $C_i$ 및 ${\Delta}H_{mix}$)들이 큰 차이를 보였으며, 또한 모두 비이상적 혼합미셀모델에 잘 일치하였으며 이상적 혼합미셀모델과는 음방향으로 크게 벗어남을 보였다.

• 콘크리트학회논문집
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• 제12권5호
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• pp.69-80
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• 2000

This paper presents the prediction of remaining service life of the concrete due to steel corrosion caused by the following three cases; carbonation, using sea sand and using deicing salts. The assessment of initiation period was generalized considering the existing perdiction models in the literature, corrosion experiment and field assessment. To evaluate the prediction equation of rust growth, the corrosion accelerating experiments was performed. The polarization resistance was measured by potentiostat and the conversion coefficient of polarzation resistance to corrosion rate was determined by the measurement of real mass loss. Chloride content, carbonation, cover depth, relative humidity, water-cement ratio(W/C), and the use of deicing salts were taken into account and the resulting prediction equation of rust growth was proposed on the basis of these properties. The proposed equation is to predict the rust growth during any specified period of time and be effective in particular for predicting service life of concrete in the case of using sea sand.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권3호
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• pp.207-211
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• 2004

Predispersed solvent extraction (PDSE) of succinic acid with Tri-n-octylamine (TOA) dissolved in 1-octanol from aqueous solutions of 50 g/L succinic acid was examined. It was found that the equilibrium data in PDSE was equal to that in conventional solvent extraction in spite of the lack of mechanical mixing in PDSE. The influence of salts on succinic acid extraction and the stability of colloidal liquid aphrons (CLAs) were also investigated. Results indicated that in the presence of sodium chloride, less succinic acid was extracted by CLAs and the stability of CLAs decreased. However, the stability of CLAs was sufficient to make PDSE practically applicable to real fermentation broth, considering the concentration range of salts in the fermentation process for succinic acid.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.417-421
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• 2003

The purpose of this paper is to study on the construction of roadbed with environmental friendly soil amendment agent. The special amendment agent used in this study is mainly composed of inorganic metal salts such as sodium chloride, magnesium chloride, potassium chloride, calcium chloride,, thus is friendly to the environment, and has a function of soil-cement-agent solidification. Various components of this agent weaken the negative function of humic acid and decompose humic acid itself. Then, the calcium cation of the cement can now be made contact directly to the soil surface. The project of local road demonstration of roadbed construction with special soil treatment agent was peformed in Northeast Thailand on August 1999 by the sponsor of Highway Department of Thailand. A series of field experiments including unconfined compressive strength were carried out to investigate the physical and mechanical characteristics of solidified roadbed treated by this solidifying agent. The results of this research showed that the roadbed using poor soil could be efficiently constructed by treatment of this amendment agent.

• 한국응용과학기술학회지
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• 제12권1호
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• pp.81-86
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• 1995

Some weight loss accelerating agents, dodecyltrimethylammonium chloride(DTAC), dodecyltrimethylammonium bromide(DTAB), dodecyldimethylammonium chloride(DDBAC), polyoxyethylene(2) dodecylbenzylammonium chloride(PDBAC), and 1-(2-hydroxyethyl)-1-benzyl-2-undecylimidazolinium chloride(AEUIC), were synthesized. As a result of weight loss treatment of the weight loss accelerating agents with NaOH to PET fiber, the increase of weight loss was the order of PDBAC > DDBAC > DTAC > DTAB > AEUIC. Among the weight loss accelerating agents, AEUIC hardly showed weight loss effect, and it was separated into two layer in the NaOH solution at the treatment concentration above 6g/L, but POBAC showed good weight loss effect of 21% that approach almost to a theoretical weight loss, 21.6%, at the concentration above 8g/L.

• Journal of Oral Medicine and Pain
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• 제23권4호
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• pp.343-352
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• 1998

This experiment was performed to investigate effects of zinc containing solution on the major normal flora Staphylococccus aureus, Streptococus mutans and Candida albicans and to observe the variation according to anionic change and concentration difference. Zinc chloride, zinc iodide and zinc acetate solution were added to werially diluted broth culture so that each final concentration might be 0.25%, 0.5%. 1%. After that, 100ul of each aliquot was spreaded on each selective media plate( Mannitol Salts Agar plate for Staphylococcus aureus, Mitis Salivarius Agar plate for Streptococcus mutans and Sabouraud Destrose Agar plate for Candida albicans). The % killing was calculated bu CFU count after incubation under the appropriate condition. 1. zinc iodide, zinc chloride, and zinc acetate solutions showed inhibitory effects on Staphylococcus aureus, Streptococcus mutans and Candida albicans. 2. The inhibitory effects on Staphylococcus aureus were ranked in order of ainc iodide, zinc chloride and zinc actate. 3. The inhibitory effects on Streptococcus mutans were ranked in orfer of zinc iodide, zinc chloride and zinc acetate. 4. the inhibitory effects on Candida albicans showed no difference among zinc iodide, zinc chloride and zinc acetate. 5. The inhibitory effects of zinc chloride and zinc acetate on Staphylococcus aureus and Streptococcus mutnas showed increasing pattern as the concentration increase. But the inhibitory effects of zinc iodide on Staphylococcus aureus and Streptococcus mutans showed no apparent difference according to concentrations and it was the case with the inhibitory effects of zinc iodide, zinc chloride and zinc acetate on Candida albicans.

• 한국수산과학회지
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• 제16권2호
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• pp.68-74
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• 1983

부산 수영만의 조간대 저질에서 moderate halophile인 Listeria denitrificans HB-38을 분리하여 생육에 필요한 NaCl 요구도를 조사한바, 해양환경조건의 배지에서는 $4\%$ NaCl에서 육상환경조건의 배지에서는 $10\%$ NaCl에서 최적농도였으며, 균생육 최적 온도는 $40^{circ}C$였고, 생육최적 pH는 7.5이었다. 그리고 비호염성인 E.coli, KPM 105와 protoplast안정성을 비교해본 결과, 더 높은 stabilizer의 농도를 요구하지는 않았으며, stabilizer로서 NaCl이sorbitol이나 sucrose보다 protoplast에 더 안정성을 주는 것으로 나타났다. HB-38균주의 succinic dehydrogenase 활성에는 NaCl 농도가 증가함에 따라 그 활성 이 증가하다가 $9\%$에서 최대에 달하였다. 반면에 이 호염성효소의 $(NH_4)_2\;SO_4$와 NaCl에 의한 염석은 비호염성인 E.coli 및 bovine liver 세포의 경우보다 더 높은 농도의 염에 의하는 것은 아니였다. 그리고 ethidium bromide에 의한 curing과 agarose gel 전기영동의 결과 HB-38은 extrachromosomal DNA를 가지지 않는 것으로 나타났다.

• 한국잠사곤충학회지
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• 제39권1호
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• pp.44-55
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• 1997

This study was carried out to find out the relationship between qualities and contraction phenomenon of silk fibers by treatment of concentrated neutral salts. The contraction effects of silk fibers showed the critical point on the treatment conditions of concentration, temperature and time, among three kinds of neutral salts such as calcium nitrate, calcium chloride and lithium bromide. But, The silk fibers, pretreated with bromide and/or formaldehyde, did not show the contraction upon treating with calcium nitrate. This indicates that tyrosine and serine can be correlated with the contraction reaction because of coupling these amino acids with bromide and formaldehyde. In conclusion, a mechanism for the contraction of silk fiber with highly concentrated calcium nitrate solution is supposed as follows. At the initial stage of ration, the water was penetrated into the amorphous regions and fibers swollen, therefore, the contraction took place mainly in amorphous regions, which have plenty of functional groups with hydroxyl residues. Then, as the calcium nitrate is penetrated into the microfibril, the gydrogen bonds of tyrosine and serine residues and broken and crystalline regions are more and more influenced by increasing concentration of calcium nitrate solution. Microgibrils of crystalline regions become entangled, contracted to linear direction and rearranged to form new stable hydrogen bonds.