• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.801-804
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• 2006

Polycarboxylate type superplasticizers(PC) have got widely used for making not only high performance concrete but low grade concrete as well. It is known that fluidity of cement with PC is affected by the characteristics of cement especially sulphate ion concentration and hydration activity. But the characteristics of PC also affect the fluidity. The fluidity of cement mortar with various types of PC was measured and critical dosage(CD) and dispersing ability(DA) was calculated. CD and DA is strongly dependent on the type of PC. And the variation of fluidity on time was affected by the type of PC also. So, it is advisable to investigate the property of PC before production of concrete and adjust it to meet the requirements of concrete depending on the materials, the time of transport and so on.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.148-149
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• 2022

The use of high-strength grout applied for facility foundations and bridges has recently been expanding in offshore wind farm. Wind farm in offshore require bearing capacity for horizontal loads such as wind, waves, and earthquakes. In order to improve the bearing force of the base part, sufficient fluidity and a certain strength should be ensured so that the high-strength grout is densely charged in the narrow space of the connection part. Therefore, in this study, changes in fluidity and strength according to the ratio of PC-based superplasticizer mixed in high-strength grout were measured. As a result, as the ratio of the superplasticizer increased, fluidity increased and strength decreased. However, the strength did not decrease when the ratio of superplasticizer was above a 0.005. Therefore, it was confirmed that the fluidity change was remarkable when a 0.005 ratio of PC-based superplasticizer were added.

• Journal of Photoscience
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• v.12 no.2
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• pp.67-73
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• 2005

Fluorescent probe techniques were used to evaluate the effect of dibucaine.HCl on the physical properties (transbilayer asymmetric lateral mobility, annular lipid fluidity and protein distribution) of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex. An experimental procedure was used based on selective quenching of 1,3-di(l-pyrenyl)propane (Py-3-Py) by trinitrophenyl groups, and radiationless energy transfer from the tryptophans of membrane proteins to Py-3-Py. Dibucaine.HCl increased the bulk lateral mobility, and annular lipid fluidity in SPMV lipid bilayers, and had a greater fluidizing effect on the inner monolayer than the outer monolayer. The magnitude of increasing effect on annular lipid fluidity in SPMV lipid bilayer induced by dibucaine.HCl was significantly far greater than magnitude of increasing effect of the drug on the lateral mobility of bulk SPMV lipid bilayer. It also caused membrane proteins to cluster. These effects of dibucaine.HCl on neuronal membranes may be responsible for some, though not all, of the local anesthetic actions of dibucaine.HCl.

• Journal of Korea Foundry Society
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• v.24 no.1
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• pp.34-39
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• 2004

The effects of casting condition and hot melt glue during Lost Foam Casting were investigated on the fluidity of Al alloy melt. The fluidity increased linearly with increasing pouring temperature in thick castings but non-linearly in thin casting due to the difference in main heat flow direction. The metal flow velocity was in range of $0.5{\sim}2.7$ cm/s in no evacuation condition and the minimum value of it was measured after the melt flow through the hot melt barrier. The mold evacuation improved the metal flow velocity by around $0.5{\sim}1$ cm/s. And the reaction zone layer thickness was about 1 cm in no-evacuation conditions but about 0.6 cm in mold evacuation condition of 710 torr due to the easier removal of pyrolsis product of EPS. And hot melt barrier thickness of 0.6 mm increased the reaction zone layer thickness up to about 2.5 cm. The fluidity decreased remarkably with an enlarged thickness of hot melt due to a lot of pyrolysis products.

• Korean Journal of Metals and Materials
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• v.50 no.7
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• pp.531-538
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• 2012

In this study, we evaluated the fluidity of the Al-Zn based alloys which exhibit excellent mechanical properties. We conducted computer simulations of fluid flow using the results of DSC, DTA analysis and Java-based Materials Properties software (J. Mat. Pro). Such computer simulations were then compared with the results obtained from experimental observations. The computer simulation results and the experimental results were very similar in fluidity length. It was found that the fluidity length of Al-Zn alloys is improved by increasing the Zn content while decreasing the solidus temperature of an alloy. In addition, we elucidate the effect of Zn addition on variations in different mechanical properties and the microstructure characteristics of (Al-xZn3Cu0.4Si0.3Fe) x=20, 30, 40, and 45 wt% alloys fabricated by gravity casting.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.162-173
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• 2015

The cellular fatty acid composition is important for metabolic plasticity in Rhodobacter sphaeroides. We explored the effects of changing the cellular ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) in R. sphaeroides by overexpressing several key fatty acid biosynthetic enzymes through the use of expression plasmid pRK415. Bacteria containing the plasmid pRKfabI₁ with the fabI₁ gene that encodes enoyl-acyl carrier protein (ACP) reductase showed a reduction in the cellular UFA to SFA ratio from 4 (80% UFA) to 2 (65% UFA) and had decreased membrane fluidity and reduced cell growth. Additionally, the ratio of UFA to SFA of the chromatophore vesicles from pRKfabI₁-containing cells was similarly lowered, and the cell had decreased levels of light-harvesting complexes, but no change in intracytoplasmic membrane (ICM) content or photosynthetic (PS) gene expression. Both inhibition of enoyl-ACP reductase with diazaborine and addition of exogenous UFA restored membrane fluidity, cell growth, and the UFA to SFA ratio to wild-type levels in this strain. R. sphaeroides containing the pRKfabB plasmid with the fabB gene that encodes the enzyme β-ketoacyl-ACP synthase I exhibited an increased UFA to SFA ratio from 4 (80% UFA) to 9 (90% UFA), but showed no change in membrane fluidity or growth rate relative to control cells. Thus, membrane fluidity in R. sphaeroides remains fairly unchanged when membrane UFA levels are between 80% and 90%, whereas membrane fluidity, cell growth, and cellular composition are affected when UFA levels are below 80%.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.26-33
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• 2014

The study investigates the effects of the type, replacement ratio and method of use of mineral admixtures on the fluidity, bleeding ratio, volumetric change and compressive strength of the grout in order to provide basic data for the development of high-quality grout for PSC bridges. In view of the results relative to the type and replacement ratio of the mineral admixtures, it appears that fly ash has practically no effect on the improvement of the fluidity nor on the reduction of bleeding and shrinkage of the grout. On the contrary, blast furnace slag and silica fume appear to have significant effect on the improvement of the fluidity or on the reduction of bleeding and shrinkage of the grout. With regard to the combined use of mineral admixtures, the combination of fly ash and blast furnace slag provides satisfactory fluidity but with significant increase of bleeding and shrinkage, whereas the combination of blast furnace slag and silica fume reduces bleeding and shrinkage but with large loss of the fluidity. On the other hand, the combination of fly ash and silica fume results in satisfactory fluidity accompanied with fair reduction of bleeding and shrinkage of the grout. In view of these results, the type, replacement ratio and method of use of the mineral admixtures are seen to influence the fluidity, bleeding and volumetric change of the grout. Accordingly, it is necessary to select the mineral admixtures considering these effects for their exploitation in the grout of PSC bridges.

• Journal of the Korean Ceramic Society
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• v.51 no.6
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• pp.584-590
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• 2014

Air-cooled slag showed grindability approximately twice as good as that of water-cooled slag. While the studied water-cooled slag was composed of glass as constituent mineral, the air-cooled slag was mainly composed of melilite. It is assumed that the sulfur in air-cooled slag is mainly in the form of CaS, which is oxidized into $CaS_2O_3$ when in contact with air. $CaS_2O_3$, then, is released mainly as $S_2O{_3}^{2-}$ion when in contact with water. However, the sulfur in water-cooled slag functioned as a constituent of the glass structure, so the$S_2O{_3}^{2-}$ ion was not released even when in contact with water. When no chemical admixture was added, the blended cement of air-cooled slag showed higher fluidity and retention effect than those of the blended cement of the water-cooled slag. It seems that these discrepancies are caused by the initial hydration inhibition effect of cement by the $S_2O{_3}^{2-}$ ion of air-cooled slag. When a superplasticizer is added, the air-cooled slag used more superplasticizer than did the blast furnace slag for the same flow because the air-cooled slag had higher specific surface area due to the presence of micro-pores. Meanwhile, the blended cement of the air-cooled slag showed a greater fluidity retention effect than that of the blended cement of the water-cooled slag. This may be a combined effect of the increased use of superplasticizer and the presence of released $S_2O{_3}^{2-}$ ion; however, further, more detailed studies will need to be conducted.

• Preventive Nutrition and Food Science
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• v.3 no.1
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• pp.56-61
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• 1998

This study was conducted to investigate the effect of dietary supplementation of vitamin A on the membrane property and ultrastructure in ethanol-administered rat livers. Male Sprague-Dawley rats weighing of 130 ~150g were fed with experimental diets for 7 weeks. The diets contained different types of vitamin A which were $\beta$-carotene, retinyl acetate and retinoic acid. After feeding theexperimental diets for 7 weeks, a dose of 3.0g ethanol (30%, W/V)/kg B.W was injected to rats intraperitoneally. Control rats received 0.9% saline containing isocaloric sucrose instead of ethanol. Plasma membrane fluidity of liver decreased in rats fed with vitamin a -Deficient diet with ethanol as compared to that of control rats. Fluidity change of liver plasma membrane that ethanol had induced was influenced by dietary supplementation of vitamin A, but not influenced by the type of supplemented vitamin. A . The ultrastructural changed of hepatic mitrochondria were observed in some rats such as vitamin A-deficient rats with ethanol. Inadequate consumptionof vitamin A contributed to ultrastructural changes such as swelled mitochondria occurred by ethanol-induced hepatotoxicity. Although accurate mechanism involved in the plasma membrane-stabilizing effect of vitamin A is still unclear, dietary supplementation of vitamin A such as retinyl acetate is neede to modulate this change. The direct involvement of membrane property on the cell damage caused by ethanol treatment remains to be established.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.81-82
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• 2011

This paper is to compare and analyze WOE created by emulsifying waste oil & WOES added by stimulant with the existing SR in order to solve the problem of strength and reduction in fluidity occurring in time of the use of waste oil to reduce the autogenous shrinkage of high strength mortar. As experimental results, in case of WOE, there almost never happened a drop in fluidity at 1% replacement and compressive strength also showed the strength value similar to Plain. On the other hand, the effect of strength improvement consequent upon the use of stimulant was found to be insufficient. The change of autogenous shrinkage generally showed a better reduction effect in shrinkage comparing to Plain. In case of WOE1, reduction effect in autogenous shrinkage was found to be more excellent than the existing SR. Accordingly, WOE1 is analyzed to be desirable if reduction in autogenous shrinkage, strength & up to the aspect of fluidity are taken into consideration.