• 생물환경조절학회지
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• 제7권1호
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• pp.55-61
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• 1998

본 실험은 배양액 내의 황산이온이 참쑥(Artemisia mongolica var. tenuifolia)의 생육에 미치는 영향을 알아보고자 수행되었다. 황산이온은 0, 0.5, 1, 2, 3mM의 농도로 처리되었는데 양액은 벨기에의 채소연구소에서 허브용양액으로 개발된 양액조성을 변형하여 이용하였다. 참쑥의 생육은 일반적으로 3mM 처리에서 좋았으며 건물률 또한 3mM 처리에서 가장 좋았다. 배양액내의 황산이온 농도가 증가할수록 참쑥의 엽록소 함량은 증가하였는데 특히 엽록소 a의 함량이 b함량에 비해 증가의 폭이 컸다. 참쑥의 무기물 함량은 배양액내의 황산이온 농도와 유의성을 보이지 않았으나 조직내 Ca의 함량은 3mM 처리에서 급격히 감소하였다. 식물에 의한 황산이온의 흡수는 배양액내의 농도가 증가할수록 증가하였는데 2mM까지는 서서히 증가 하다가 3mM에서 현저하게 증가하였다. 1mM 황산이온 처리에서 정유의 함량은 가장 높았으나 그 이상으로 농도가 증가할 경우 정유의 함량은 오히려 감소하였다.

• 대한가정학회지
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• 제42권8호
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• pp.113-121
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• 2004

This study used cupric sulfate as a bum-out agent. The concentration of cupric sulfate, temperature and time were varied with glycerin included or excluded on the properties of polyester ground fabrics. The results are as follows. The effect of carbonization with glycerin included was decreased, but removal of carbide with glycerin included was easier than that with glycerin excluded. The white index and tensile strength of polyester ground fabrics were decreased as the processing concentration, temperature and time increased. The shrinkage was increased as the processing concentration, temperature and time increased. The optimum conditions with cupric sulfate as the bum-out agent was 5％ concentration, 140$^{\circ}C$, 3min., and 3kgf/cm$^2$ and with cupric sulfate added to glycerin was 5％ concentration, 150$^{\circ}C$, 5min., and 3kgf/cm$^2$.

• Computers and Concrete
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• 제10권1호
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• pp.79-93
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• 2012

This paper estimates theoretically the diffusion-reaction behaviour of sulfate ion in concrete caused by environmental sulfate attack. Based on Fick's second law and chemical reaction kinetics, a nonlinear and nonsteady diffusion-reaction equation of sulfate ion in concrete, in which the variable diffusion coefficient and the chemical reactions depleting sulfate ion concentration in concrete are considered, is proposed. The finite difference method is utilized to solve the diffusion-reaction equation of sulfate ion in concrete, and then it is used to simulate the diffusion-reaction process and the concentration distribution of sulfate ion in concrete. Afterwards, the experiments for measuring the sulfate ion concentration in concrete are carried out by using EDTA method to verify the proposal model, and results show that the proposed model is basically in agreement with the experimental results. Finally, Numerical example has been completed to investigate the diffusion-reaction behavior of sulfate ion in the concrete plate specimen immersed into sulfate solution.

• Journal of Microbiology
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• 제43권2호
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• pp.166-171
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• 2005

In order to determine the effects of sulfate concentration on the anaerobic dechlorination of polychlorinated biphenyls, sediments spiked with Aroclor 1242 were made into slurries using media which had various sulfate concentrations ranging from 3 to 23 mM. The time course of dechlorination clearly demonstrated that dechlorination was inhibited at high concentration of sulfate due to less dechlori-nation of meta-substituted congeners. When the dechlorination patterns were analyzed by the calculation of Euclidean distance, the dechlorination pathway in the 3 mM sulfate samples was found to be different from that observed in the 13 mM samples, although the extent of dechlorination in these two samples was similar. It is possible that the dechlorination in the high sulfate concentration samples is inhibited by the suppression of growth of methanogen, which have been shown to be meta-dechlorinating microorganisms.

• 한국환경보건학회지
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• 제22권3호
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• pp.64-71
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• 1996

Measurement of concentration and size distribution of TSP, ammonium, nitrate and sulfate were made from Mar., 1991. to June., 1992 in Seoul. The seasonal variation of concentration and size distribution of aerosols has been investiated. Aerosol were collected and size frationated by Andersen air sampler. Size classified samples were extrated with deionized water and analyzed for ammonium, nitrate and sulfate by ion chromatography. As the results of measurement, the average of concentration and MMAD(mass median aerodynamic diameter) were $118.58 \mu g/m^3$, and $2.77 \mu m$ for TSP, $1.92 \mu g/m^3$ and $1.35 \mu m$ for ammonium, $1.34 \mu g/m^3$ and $1.58 \mu m$ for nitrate, $8.52 \mu g/m^3$ and $2.15 \mu m$ for sulfate. The Seasonal variation of concentration and size distribution was observed for ammonium, nitrate and sulfate. The concentration peak of TSP was observed in coarse particles in spring and observed in fine particles in winter. The concentration's distribution of TSP, ammonium, nitrate and sulfate was observed bimodal type during all season.

• Computers and Concrete
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• 제33권1호
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• pp.1-11
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• 2024

Aggressive environmental conditions, and especially the acidic effects of sulfate ion penetration, have reduced the lifetime of concrete structures in some areas, especially coastal and marine areas. In this research, at first, samples made of type II and V cement were kept in a solution of magnesium sulfate (MgSO₄) for a period of 90 and 180 days, the change of appearance. Field Emission Scanning Electron Microscopy (FE-SEM) and X-Ray Diffraction (XRD), were used to analyze the microstructure and the complex mineral composition of the concrete after exposure to corrosive environments. Then solving the differential equation governing the sulfate ion penetration, which is based on the second Fick law, it has been tried to determine the concentration of sulfate ions inside the concrete. In the following, an attempt has been made to improve the prediction of sulfate ion concentration in concrete by using Crank's penetration equation. At the same time, the coefficient in the Crank's solution have been optimized by using the Particle Swarm Optimization (PSO algorithm). The comparison between the results shows that the values obtained from Crank's relation are closer to the experimental results than the equation obtained from Fick's second law and shows a more accurate prediction.

• 대한치과교정학회지
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• 제28권5호
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• pp.877-891
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• 1998

교정장치의 직접부착을 위하여 일반적으로 사용되고 있는 산부식법의 대체가능 방법중 하나는 결정형성법이며, 폴리아크릴산과 황산이온은 결정형성액의 주요 물질로 알려져 왔다. 이 연구는 황산이온농도와 폴리아크릴산의 농도변화가 결정형성에 미치는 영향을 관찰하여 결정형성용액에 관한 기초자료를 획득하기 위하여 시행되었다. 분자량 5,000의 폴리아크릴산을 $10\%,\;20\%,\;30\%$ 및 $40\%$ 용액으로 만들고, 각각의 용액에 황산이온 농도가 0.1M, 0.2M, 0.3M, 0.5M 및 1.0M이 포함되는 총 20가지의 실험용 결정형성용액을 제조하고, 이들을 법랑표면에 60초간 반응시킨 후, 주사전자현미경 사진을 촬영하여 결정 피복도, 결정 길이 및 결정형태 분포의 균일성을 평가하여 다음과 같은 결론을 얻었다. 1. 폴리아크릴산 용액은 법랑질 표면을 경미하게 부식시켰으며, 농도에 따른 부식효과의 차이는 없었다. 2. 폴리아크릴산의 농도는 결정형성에 적은 영향을 미쳤다. 특히 $20\%-40\%$사이의 폴리아크릴산 용액은 결정형성에 영향을 미치지 않았다. 3. 황산이온 농도는 결정형성의 주요인자이다. 0.2M이상의 황산이온이 포함된 폴리아크릴산 용액에서 결정이 형성되었다. 4. $20\%\~40\%$ 폴리아크릴산 용액에 포함된 황산이온농도가 결정 피복도에 미치는 영향은 황산이온 농도가 어느한도까지 증가하면 결정 피복도도 증가하나 그 이상에서는 감소하는 경향으로 나타났다. 이 실험에서는 0.5M황산이온이 포함된 실험용액이 가장 높은 결정 피복도를 나타냈으며, 최대의 결정 피복도를 나타내는 황산이온 농도는 0.5M, 혹은 0.5M에서 1.0M사이에 있을 것으로 추정되었다. 5. 폴리이크릴산 용액내의 황산이온 농도가 증가할수록 결정길이는 작아지는 경향을 보였다. 6. 폴리아크릴산 용액내의 황산이온 농도는 결정 형태의 분포에 영향을 미친다. 황산이온의 농도가 낮을수록 spherulitic형 배열의 결정형성이 증가하고, 황산이온농도가 증가하면 무정형 배열의 결정형성이 증가하는 경향을 보였다. 7 이 연구에서 가장 양호한 실험용 결정형성용액은 0.5M 황산이온이 포함된 $30\%$ 폴리아크릴산 용액이었다.

• 한국염색가공학회지
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• 제22권3호
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• pp.220-228
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• 2010

This study examines the scouring effect of pectinase on ramie fabric and influence of sodium sulfate as an activator for pectinase. The scouring effects were measured by the weight loss and pectin contents. SEM, weight loss, stiffness, moisture regain and dye ability of ramie fabric teated with pectinase/sodium sulfate were also measured. When ramie fabrics were desized with $\alpha$-amylase, the optimum conditions were pH 6.5 at $60^{\circ}C$ for 80 min with 1%(o.w.f) $\alpha$-amylase concentration. When ramie fabrics were scoured with pectinase, the optimum conditions were pH 8.5 at $55^{\circ}C$ for 30 min with 10%(o.w.f) pectinase concentration. Addition of sodium sulfate improved enzyme activity significantly, which increased proportionally with increasing sodium sulfate concentration. When 50 g/l of sodium sulfate was added, the surface became cleaner compared to the enzyme treatment without salt: weight and tensile loss, moisture regain and dyeability of the treated fabrics increased, while pectin contents and stiffness decreased. Therfore, sodium sulfate was effective activator for the pectinase treatment of flax fiber.

• Geomechanics and Engineering
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• 제10권6호
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• pp.807-826
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• 2016

In this study, aiming to investigate the effects of sulfate attack on cement stabilized highly plastic clay; an experimental study was carried out considering the effects of cement type, sulfate type and its concentration, cement content and curing period. Unconfined compressive strength and chloride-ion penetration tests were performed to obtain strength and permeability characteristics of specimens cured under different conditions. Test results were evaluated along with microstructural investigations including SEM and EDS analyses. Results revealed that use of sulfate resistance cement instead of normal portland cement is more plausible for soils under the threat of sulfate attack. Besides, it was verified that sulfate concentration is responsible for strength loss and permeability increase in cement stabilized montmorillonite. Finally, empirical equations were proposed to estimate the unconfined compressive strength of cement stabilized montmorillonite, which was exposed to sulfate attack for 28 days.

• 한국의류학회지
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• 제28권1호
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• pp.131-142
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• 2004

When the cotton/polyester fiber mixed fabrics were treated with ferrous sulfate and oxalic acid for burn out finishing, it was examined how the effects of process conditions as concentration of burn out agents, temperature, time and pressure act onto the properties of polyester ground fabrics. The results are as follows. The effect of burn out finishing by pressure was greated in 3 kgf/$\textrm{cm}^2$. The properties as white index and tensile strength of polyester ground fabrics were decreased according as processing concentration, temperature time increases. The shrinkage was increased according as processing concentration, temperature time increases. The optimum condition of burn out agents to ferrous sulfate was 30% concentration, 150$^{\circ}C$, 1 min, 3 kgf/$\textrm{cm}^2$ and to oxalic acid was 10% concentration, 110$^{\circ}C$, 1min, 3 kgf/$\textrm{cm}^2$. And the optimum of ferrous sulfate and oxalic acid used in combination was 10% ferrous sulfate and 7% oxalic acid, 110$^{\circ}C$, 1 min., 3 kgf/$\textrm{cm}^2$.