• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.149-156
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• 1997

In order to improve compressive strength of cement mortar, powder admixture(FAS) was mmufactured by mixing fly ash. Il-anhydite and silica hume, and superplasticizer was used for the control of fluidity reduction with the use of this admixture. Cement was substituted by 10, 20wt% of FAS respectively. At W/S = 0.40, the fluidity of' cement paste substituted by PAS was decreased. NSF and NT-2 were very effective fbr the control of fluidity reduction. As the particle size of U -anhydrite was fine, the fluidity of cement mortar was increased. The fluidity reduction of cement mortar substituted by 10wt% of FAS was controlled. The compressive strength of cement mortar substituted by 10wt% of FAS showed higher. value than that of 20wt%, expecially specimen(C1) substituted by 10wt% of $\gamma$ had the highest compressive strength value.

• YAKHAK HOEJI
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• v.46 no.3
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• pp.155-160
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• 2002

Through a modification of allicin structure a disagreeable odor and chemical instability of allicin can be improved. 3-Alkoxy-6-allylthiopyridazine derivatives exhibit a superior effect for prevention and treatment of hepatic diseases induced by carbon tetrachloride and aflatoxin B1 and for prevention of human tissues from radiation. These compounds inhibit also efficiently SK-Hep-1 cell proliferation through induction of apoptosis. So another 4,5-mono- or di-substituted 3-alkyloxy-6-allylthiopyridazine derivatives were synthesized on purpose to find out SAR of allylthiopyridazine in hepatoprotective and hepatotherapeutic acitivitis and to develop more effective drug candidate.

• Archives of Pharmacal Research
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• v.22 no.4
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• pp.391-397
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• 1999

The quaternary ammonium cephalosporin derivatives were prepared with various pyridines substituted at the 3 or/and 4 position. Their in vitro antibacterial activities were determined and substituent effect on pyridine nucleus was studied. Preparation of substituted pyridines are also described.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.238.2-238.2
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• 2003

The synthesis of a new series of 1${\beta}$-methylcarbapenems having the substituted aminoethyl-carbamoylpyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituent on the pyrrolidine ring was investigated. In particular. the compound 11 g having piperazinyl urea moiety showed the most potent antibacterial activity.

• Membrane Journal
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• v.11 no.3
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• pp.133-139
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• 2001

The hydorgen ions in PVA/SSA membranes were substituted with monovalent metal ions, $Li^{+}$, $Na^{+}$, $K^{+}$, divalent metal ion forms, $Mg^{2+}$, $Ca^{2+}$, $Ba^{2+}$, trivalent metal ion forms, $Al^{+}$. The effect of exchange with metal ions was investigated through the swelling measurement and pervaporative experiments for water-ethanol and water-methanol mixtures at various operating conditions. In addition, ESCA analysis was carried out to study the substitution of the metal ions in membranes. The swelling ratio decerased in the sequence of $Li^{+}$, $Na^{+}$, $K^{+}$ and this might be due to the 'salting-out` effect while the swelling ratios for divalnet and trivalent ion-substituted membranes were affected by the combined effect of salting-out, electrostatic crosslinking and extent of metal ion substitution. For the pervaporation performance, PVA/SSA-$H^{+}$membrane showed the lowest flux and highest separation factor for all aqueous ethanol solutions. The typical results of the flux, 59 g/$m^{2}$hr and the separation factor, 44 were obtained at $50^{\circ}C$ for 90% ethanol aqueous mixture. For water-methanol solutions, the PVA/SSA membranes substituted with monovalent PVA/SSA membranes substituted with divalent and tribalent metal ions, both `salting-out` and electrostatic effects affected the pervaporative results.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.562-569
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• 1994

The retention data of twenty one monosubstituted phenols in the eluent systems containing 30∼70% of methanol or acetonitrile as organic modifiers, on $ C_{18}$ and Phenyl columns were collected to investigate the effect of the substituted groups on the retention of phenols. The capacity factors of the solutes except amino phenols are greater on $ C_{18}$ than on Phenyl column. And all the solutes have shown greater capacity factors in methanol-water than that in acetonitrile-water as a mobile phase. Generally the elution order between meta and para isomers of monosubstituted phenols in consistent (p < m) regardless of the polarity of the substituted group. But the elution order between ortho and meta isomers of phenol varies with regard to the polarity of the substituted group. The retention of the monosubstituted phenols has been influenced by the interaction between the solute and unreacted silanol of columns as well as the interaction between the solute and $ C_{18}$ or phenyl group of columns. And then, the effect of unreacted silanol on the retention of the monosubstituted phenols is greater on $ C_{18}$ than on Phenyl column. And the greater hydrogen bonding acceptor basicity(${\beta}$) of the substituted group is, the greater this effect is. The relationship between the retention of the monosubstituted phenols and their parameters such as van der Waals volume(VWV) and hydrogen bonding acceptor basicity(${\beta}$) has been investigated. The good linearity has been observed in the plot log k' vs. (1.01VWV/100-1.84${\beta}$). In consequence, the retention of the monosubstituted phenols on $ C_{18}$ and Phenyl columns can be easily predicted by the parameter (1.01VWV/100-1.84${\beta}$).

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.204-205
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• 1989

• Journal of the Korean Chemical Society
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• v.30 no.2
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• pp.172-180
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• 1986

The Hammett's substituent constants were analyzed for the substituted-benzoic acid, -benzene and -naphthalene by LCAO MO method. Hammett's ${\sigma}$-values have been theoretically proved to treat as the sum of independent contribution of inductive effect and resonance effect. That is, Is (static inductive effect) and Id (dynamic inductive effect) corresponding to inductive effect are chosen as net charge and approximate self atom polarizability indices respectively, and ${\Delta}E^{HOMO}$ which is the difference in HOMO energy level between substituted molecule and unsubstituted molecule as resonance effect. In conclusion, it has been found that the observed ${\sigma}$-values depend on the sum of Id, Is and ${\Delta}E^{HOMO}$.

• Archives of Pharmacal Research
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• v.26 no.7
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• pp.511-515
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• 2003

Quinazolinones, 2-substituted and 3-substituted, mainly synthesized by microwave irradiation, were subjected to anti-platelet aggregation and inhibition of superoxide anion generation assays. Interestingly, 2-phenyl-4-quinazolinone (4) exhibited significant inhibitory activities toward platelet aggregation and neutrophil activation, and it might therefore serve as a prototype lead compound.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1135-1142
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• 2010

A series of N(2)-benzothiazolyl substituted tetrahydroindazoles has been synthesized via cyclic ${\beta}$ keto esters. Optimum reaction condition was found as acidic toluene and effect of higher acidity towards substituted hydrazines in situ was described. Synthesized compounds have been achieved as single isomer and characterized by using 1D and 2D NMR spectral reports. Antimicrobial screening was carried out for the synthesized compounds along with a series of N(2)-pyridyl tetrahydroindazoles.1 The results of the in vitro antimicrobial screening studies revealed that compounds 13, 16 against Staphylococcus aureus, 11 against Escherichia coli, 10-12, 16 against Pseudomonas aeruginosa and 12 against Klebsiella pneumoniae recorded almost two-fold better activity compared to the standard drug used.