• Archives of Pharmacal Research
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• 제4권1호
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• pp.33-41
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• 1981

The prepared dextran sulfates were characterized by measuring the reduced viscosisty at five different concentrations to obtain an intrinsic viscosity in both phosphate and tris buffers, pH 7.4, ionic strength of 0.1 Dextran sulfates having 0.81, 1.06 sulfate groups per hexose unit have reduced viscosity value below 40 ml/g whereas dextran sulfates having 1.21, 1.43, 1.69 sulfate groups per hexose unit have reduced viscosity value over 40 ml/g. Dextran sulfate having 1.21 sulfate groups per hexose unit had highest value of reduced viscosity. The reduced viscosity of dextran sulfate in tris buffer was always higher than that in phosphate buffer regardless of the sulfate content of dextran sulfate. The influence of the sulfation of the dextran sulfate. The influence of the sulfation of the dextran sulfate molecule on the dextran sulfate-LDL interaction was studied with three different dextran sulfate molecules. Dextran sulfate molecules having more than one sulfate group per hexose unit. The dextran sulfate having 0.81 sulfate groups per hexose unit showed considerably different precipitation curves in phosphate and tris buffers. This peculiar behavior of dextran sulfate having 0.81 sulfate groups per hexose unit in the two buffer systems was not noticed with dextran sulfate having more than one noticed with dextran sulfate having more than one sulfate group per hexose unit.

• Computers and Concrete
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• 제16권6호
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• pp.847-864
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• 2015

This study aimed to develop models of sulfate diffusion and ettringite content profile in cement paste for the predication of the damage behavior in cement paste subject to external sulfate. In the models, multiphase reaction equilibrium between ions in pore solution and solid calcium aluminates phases and the microstructure changes in different positions of cement paste were taken into account. The distributions of expansive volume strain and expansion stress in cement paste were calculated based on the ettringite content profile model. In addition, more sulfate diffusion tests and SEM analyses were determined to verify the reliability and veracity of the models. As the results shown, there was a good correlation between the numerical simulation results and experimental evidences. The results indicated that the water to cement ratio (w/c) had a significant influence on the diffusion of sulfate ions, ettringite concentration profile and expansion properties in cement paste specimens. The cracking points caused by ettringite growth in cement paste specimens were predicted through numerical methods. According to the simulation results, the fracture of cement paste would be accelerated when the specimens were prepared with higher w/c or when they were exposed to sulfate solution with higher concentration.

• 한국세라믹학회지
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• 제11권1호
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• pp.29-35
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• 1974

Effect of calcium sulfate and barium sulfate on the formation of portland cement clinker was studied by means of chemical analysis. DTA and X-ray diffraction analysis. In the presence of liquid phase, effect of the additives on the formation of tricalcium silicate was examined according to the reaction, 2CaO.$SiO_3$＋CaO$\longrightarrow$3CaO.$SiO_3$, which is the principal reaction in portland cement clinkerization, and optimum conditions in firing clinker concerning amount of additive, firing time and temperature were determined, and its kinetics was referred to. The experimental results are summerized as follow: (1) Appropriate burning temperature range of cement clinker is more limited as the content of calcium sulfate in clinker is increased. Amount of calcium sulfate, firing time and temperature in proper condition of clinkerization is related to each others. Being added suitable quantity of calcium sulfate, firing temperature of clinker can be lowered about $100^{\circ}C$. (2) When 3-5 mole% of calcium sulfate is added, firing time of 15-30 minutes at about $1380^{\circ}C$ is reasonable, and if the content is over7 mole %, firing for 1 hr. or more at $1350^{\circ}C$ is anticipated to be optimum condition. (3) In the reaction of tricalcium silicate formation, the role of barium sulfate as a mineralizer is similar to that of calcium sulfate, but the optimum firing temperature of cement clinker containing barium sulfate tends to be 20-$30^{\circ}C$ higher than that of clinker containing calcium sulfate. (4) When barium sulfate is used as mineralizer, 2-3 mole % of it to tricalcium silicate is recommended and if it is added more than this amount, free CaO is increased rapidly in clinker and alite formation is inhibited.

• 한국환경과학회지
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• 제25권5호
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• pp.645-654
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• 2016

For the purpose of reuse the wasted by-products from the skate process to the health functional food or medicinal material, chondroitin sulfate was extracted from the skate cartilage with the method of hydrolysis with protease enzyme, and the contents of chondroitin sulfate and hydrolyzed protein were measured qualitatively and quantitatively. The effects of chondroitin sulfate on body weight or liver weight changes, hepatotoxicity elimination and anti-inflammatory actions were measured from in vivo test with feed-treated mice. From the hydrolytic extraction of skate cartilage with the mixture of 1% alcalase and 1% protease for 4 hours, the extraction yield of chondroitin sulfate was about 32.55%. The content and molecular weight of chondroitin sulfate was 26.63% and $2.85{\times}10^5Da$., respectively and the content ratio of chondroitin sulfate to protein was measured to 1 to 2.76 with gel permeation chromatography. For the odor component, trimethylamine decreased about 30% but almost not ammonia from chondroitin sulfate with the treatment of activated carbon. From the feeding chondroitin sulfate to mice, the control effect of body and liver weights decrease was measured, anti-inflammatory action and hepatotoxicity elimination action were also measured. From these results, process operation conditions for manufacturing of chondroitin sulfate were suggested.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.213-218
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• 1992

Sisomicin 발효중에 magnesium sulfate의 첨가에 의해 일어나는 발효양상의 변화와 항생물질의 수율의 증가에 미치는 영향을 분석하였다. 균체증식을 DNA함량으로 나타낼 때 trophophase와 idiophase가 서로 분리되었으나, 건조중량으로 나타낼 때 구별되지 않았다. 발효중에 magnesium sulfate의 첨가는 균체내에 축적되는 항생물질을 균체외로 유리시키며, 이러한 효과는 균체의 비생산성을 높히게 되어 항생물질의 수율을 증가시키는 것으로 사료된다. 한편, magnesium sulfate의 최적 첨가조건은 배양시작 1일 후에 100mM을 첨가할 때 얻어지며, 첨가하지 않은 경우에 비교하여 최종 발효수율이 3배 이상 증가되었다.

• 한국토양비료학회지
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• 제31권3호
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• pp.271-276
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• 1998

양파의 연작재배시(連作栽培時) 질소비종(窒素肥種)(요소, 유안)과 가리비종(加里肥種)(염화가리, 황산가리), 그리고 토양개량제(土壤改良劑)(석회)시용시 양분흡수량(養分吸收量)과 생육 그리고 수량성을 검토하고자 전남 무안군의 용계통(龍溪統)에서 천주황을 공시품종으로 하여 시험한 결과를 요약하면 다음과 같다. 식물체중(植物體中) N P K 흡수량(及收量)은 요소 및 염화가리시용구보다 토양진단시비(土壤診斷施肥)에 의해 유안과 황산가리 혼합시용(混合施用)으로 흡수량이 높았다. 토양중(土壤中) 황함량(黃含量)은 수확기(收穫期)보다는 생육중기(生育中期)에, 식물체중(植物體中) 황함량(黃含量)은 수확기(收穫期)에 가장 높았으며 구중(球中)보다는 경엽(莖葉)에서 높았다. 양파구중(球中) 당도(糖度)는 7.43~8.23 Brix로 차이가 있었으며 구(球)의 크기별로는 소구(小球)보다는 대구(大球)에서 높았다. 토양진단시비(土壤診斷施肥)에 의한 유안과 황산가리 혼용시용(混用施用)으로 건물중(乾物重)의 증가 및 구(球)의 상품율(上品率)이 높아 관행에 비해 2~6% 증수되었다.

• 한국약용작물학회지
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• 제6권1호
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• pp.1-5
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• 1998

강원도 평창에서 송어 양식후 배출되는 냉수를 이용하여 고추냉이를 재배하면서 계절 및 생육기간에 따른 근경의 allyINCS 함량 변화를 조사하고 화학비료의 엽면시비에 따른 allyINCS의 함량증가를 꾀하여 품질을 높이고자 시험한 결과는 다음과 같다. 1. 생육초기부터 생육후기인 이듬해 3월 개화기까지 생육기간의 경과에 따라 근경의 allyINCS 함량은 증가되는 경향이었으나 개화말기인 5월경에는 급격히 저하되었다. 2. 요소 1% 수용액 엽면시비는 대체로 생육을 촉진시켜 근경중을 증가시키거나 allyINCS 함량 증가에는 효과가 없었다. 3. 황산염을 함유한 비료(황산암모늄, 황산칼륨)의 엽면시비는 근경중과 근경의 allyINCS함량을 증가시켰는데 , 황산암모늄보다 황산칼륨 처리가 근경중 및 근경의 allyINCS 함량 증가에 더 효과적이었으며 황산 칼륨처리로 근경중이 44%, allyINCS 함량이 38% 증가 되었다. 4. 요소 1%와 황산암모늄 1% 수용액의 혼합처리는 고농도로 인하여 생육장애를 보여 근경중은 대조구와 비슷하였으나 근경의 allyINCS 함량은 47% 증가되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.953-956
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• 2006

Sulfate resistance of mortar specimens with or without alkali-free accelerator exposed to sulfate solutions for 360 days was investigated. Test results confirms a negative effect of alkali-free accelerator on the sulfate deterioration, irrespective of attacking sources. Based on the ASTM C1012 expansion test, the experimental findings demonstrated that higher $C_3A$ content in cement led to the higher expansion, especially in the mortar specimens with alkali-free accelerator.

• 콘크리트학회논문집
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• 제12권5호
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• pp.141-151
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• 2000

Compressive strength, sulfate deterioration factor(SDF) and length change of 5 types of mortars immersed in sodium sulfate solution were observed. As the results of tests, it was found that the sulfate resistance of blended cement mortars were superior to that of portland cement mortars. Pore volume with diameter larger than 0.1 $\mu\textrm{m}$ of 5 types of pastes indicated that the micro-structures of blended cement pastes were denser, due to pozzolan reaction and latent hydraulic properties, than those of portland cement pastes. The XRD, ESEM, EDS and TG analyses demonstrated that the reactants such as ettringite and gypsum were significantly formed in portland cement pastes. Besides, compared with the $Ca(OH)_2$ content of ordinary portland cement pastes immersed in water and sodium sulfate solution, the $Ca(OH)_2$ contents of fly ash blended cement and ground granulated blast-furnace slag cement paste were about 58% and 28% in water, and 55% and 20% in sodium sulfate solution, respectively.

• 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.