• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.105-113
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• 2006

This paper presents the results of an experimental investigation carried out to evaluate the mechanical properties of concrete mixtures in which fine(S) and coarse(G) aggregate was fully replaced with fly ash(FA). And flowability reduction problem in a large amount of fly ash concrete settled addition water($W_f$) in concrete mixture. In the test, water-cement ratio($W_c/C$) was 0.35, 0.45, and water-fly ash ratio($W_f/FA$) was 0.35, 0.45. The fly ash replacement is two different method of P and Q. The P method is mix property that the fly ash and addition water($W_f$) weight is equal to the aggregate weight [ $FA+W_f$ = G (or S)]. The Q method is mix property that fly ash is equal to aggregate weight, and added addition water($W_f$) [$FA+W_f$ > G (or S)]. Test were performed for properties of fresh concrete and compressive strength were determined at 3, 7, 28 and 91 days. The result, compressive strength was improvement that $W_c/C=0.35$, $W_f/FA=0.35$ and fine aggregate replacement in P method series than others. The flowability at Q method was improvement result than P method, but compressive strength was not. Test results indicate significant improvement in the strength properties and flowability of plain concrete by the inclusion of fly ash as fully replacement of fine and coarse aggregate, and can be effectively the fly ash replacement method.

• 어항어장
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• s.28
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• pp.26-31
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• 1994

• 레미콘
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• s.85
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• pp.22-33
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• 2005

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.282-290
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• 2013

In this study, the adjustment range of mixture factor with replacement mineral admixture was reviewed to secure the mixture change data of high volume concrete compared to general concrete. When changing the concrete mix to high volume concrete within the universal concrete mixing, the adjustment range of mixture to ensure optimum quality is as follows. Unit-water content is $20{\sim}30kg/m^3$ downward. Fine aggregate ratio dropped by approximately 1% when W/B was reduced by 5%, and it is reduced by approximately 0.12% when there is a 5% increase in the total replacement rate. When the FA replacement rate was increased by 5%, the AE agent was approximately 20% to 30% higher compared with the conventional one. When the FA and BS replacement rate rose by 5%, W/B was reduced by about 1 to 4%.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.89-96
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• 2011

In this study, increasing the range of replacement rate of FA with concrete properties were analyzed to provide basic data of FA replacement 0-40 % and curing temperature $5-35^{\circ}C$ range. As a result of the increased fluidity in proportion to the increase in FA, but decreased air. Setting time delayed at replacement rate increases and low temperature, simple insulation temperature history of the FA up to 40 % replacement rate increases the maximum temperature was low $8^{\circ}C$, the highest temperature reaching time delay of 13 hours. FA replacement up stream of the curing temperature, compressive strength compared to the higher plane, it was found that improved strength development. In carbonation tests with increasing the replacement ratio of FA carbonation depth was increased. Therefore, continued research on carbonation measures was to be necessary.

• Applied Biological Chemistry
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• v.42 no.3
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• pp.252-255
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• 1999

Inhibition activities$(pI_{50})$ of chalcone derivatives as substrate with farnesyl protein transferase(FPTase) were determined in vitro. The structure activity relationships(SAR) between the activity and physicochemical parameters of X & Y-substituents on the phenyl groups were analyzed by Free-Wilson and Hansch method. X-substituents on the benzoyl group have the more important role to inhibition activity than Y-substituents on the styryl group. Among them, none substituent, 8 showed the highest FPTase inhibition activity$(pI_{50}=4.30)$. Particularly, the SAR equation could be formulated, showing a parabolic relationship between the activity and hydrophobicity(logP) where the optimal value$({\Sigma}logP)_{opt}$ was 3.915. And also the activity depends on the steric effect(Es > 0) with X-substituent and the resonance effect(R < 0) with electron donating Y-substituents. Based on the results of SAR analyses, the interactions between substrates and receptor, FPTase, could be assumed.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.597-600
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• 2008

Correspond in chloride content increase by sea sand uses of bad quality using recycled fine aggregate in this research. together, examined basic properties of matter for activation of been using recycled fine aggregate use definitely. Also, super fundamental principles that is shortcoming that blast furnace slag differential speech has prevents problem of decline and change of countenance limestone power differential speech by purpose to contribute in early age strength as Filler role special quality examine. As experiment result, compressive strength at recycled fine aggregate 10%, limestone power 20% metathesis the highest compressive strength value appear, According to recycled fine aggregate metathesis rate increase, the chloride content reduced by 0.127 ㎏/m$^3$s(metathesis rate 0%), 0.119 ㎏/m$^3$s (metathesis rate 10%), 0.112 ㎏/m$^3$s (metathesis rate l20%), 0.097 ㎏/m$^3$s (metathesis rate 30%).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.4
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• pp.329-335
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• 2013

Three-dimensional quantitative structure-activity relationships (3D-QSARs) models between the substituents with changing groups ($R_1$ & $R_2$) of 4-hydroxybenzyl alcohol (4-HBA) derivatives as substrate molecule and their inhibitory activities against tyrosinase were derived and discussed quantitatively. The optimized CoMSIA FF model showed the best predictability and fitness ($r^2$ = 0.858 & $q^2$ = 0.951). The contour maps of the optimized CoMSIA FF model showed that, the inhibitory activities of the analogues against tyrosinase were expected to increase when hydrophobic (Hy) favor, negative charge (E) favor, steric (S) disfavor and hydrogen bond donor (HD) disfavor groups were substituted at the $R_2$ position. When the hydrogen bond donor (HD) favor groups were substituted at the $R_1$ position, it is predicted that the substituents will be able to increase the inhibitory activity.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.417-420
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• 2008

In this study, the characteristics of strength development and hydration heat on high volume fly ash concrete(HVFAC) was experimentally investigated. Two levels of W/B were selected. Seven levels of fly ash replacement ratios and two levels of silica fume replacement ratios were adopted. In the concrete mix, the water content of $125kg/m^3$ was used, which is less than that of usual water content. As a result, it appeared that the compressive strength gradually decreased with increasing fly ash replacement ratio at the early age, but the difference of strength up to replacement ratio of 50% was little at the age of 91 days because of the pozzolanic reaction of fly ash. The effect of hydration heat reduction on the concrete was affected by the fly ash replacement ratio. When the replacement ratio was over 30%, the reduction efficiency of hydration heat was large.

• Journal of the Korean Geotechnical Society
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• v.27 no.11
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• pp.17-25
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• 2011

In this study, we considered the bearing capacity of strip footing over clay layers partially replaced by sand. The FEM analysis is performed to calculate the ultimate bearing capacity. Partial replacement is defined by multiples of footing width(B) and inclination of sides. The cases(B'=inf.) of sand layers equal to clay layers are preferentially conducted. The baring capacity of B'=inf. is comparative value for bearing capacity of partial replacement layers. ${\beta}$ is the ratio of ultimate bearing capacity of B'=inf and partial ultimate bearing capacity replacement. ${\beta}$ is used to analyze the characteristic of bearing capacity of clay layers partially replaced by sand. Each of the three undrained shear strengths of clay and friction angles of sand is considered. The result of this analysis shows that ${\beta}$ depends on sand depth.