• Applied Science and Convergence Technology
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• v.23 no.6
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• pp.366-370
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• 2014

ZnO:Al transparent conductive films were deposited on glass substrates by RF magnetron sputtering technique and annealed by rapid thermal annealing system. The influence of annealing time on the structural, electrical, and optical properties of ZnO:Al thin films was investigated by atomic force microscopy, X-ray diffraction, Hall method and optical transmission spectroscopy. As the annealing time increases from 0 to 5 min, the crystallinity is improved, the root main square surface roughness is decreased and the sheet resistance is decreased. The lowest sheet resistance of ZnO:Al thin film is 90 ohm/sq. The reduction of sheet resistance is caused by increasing carrier concentration due to substituent Al ion. All films are transparent up to 80% in the visible wavelength range and the adsorption edge is a blue-shift due to Burstein-Moss effect with increasing annealing time.

• Textile Coloration and Finishing
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• v.30 no.1
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• pp.1-8
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• 2018

In the present study, three morpholine substituted crystal violet lactone (CVL) have been synthesized to monitor the thermochromic property. This work is explaining the role of substituent on the lactone ring. The methyl substituents induced greater chromic effects than the chloro substituents. Furthermore, the three-component mixtures that contained CVL, bisphenol-A, and methyl stearate were used to analyse the thermochromic effect of the CVLs as bulk samples with various temperature. The thermochromic properties of the CVLs were evaluated using solid-state UV-Vis and FT-IR spectroscopic techniques. Finally, one of the synthesized CVL has been successfully converted into the form of a test paper similar to pH paper for use as thermal indicators.

• Macromolecular Research
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• v.11 no.2
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• pp.92-97
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• 2003

Model compounds and polymers having N-substituted 1,2-diphenylmaleimide moieties were synthesized and characterized by NMR, IR, UV, and fluorescence spectroscopy. The fluorescence intensity could be controlled by N-substituents of model compounds and polymers. As the structure of an N-substituent of them was bulkier, or the electron density of an N-substituent was denser, the photoluminescence intensity was increased. All the compounds showed greenish yellow photoluminescence with the maximum intensity between 510 and 537 nm. From quantum efficiency data of the model compounds and the polymers, the fluorescence intensity of the polymer 11 was higher than that of the model compound 4.

• Journal of the Korean Society of Safety
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• v.3 no.2
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• pp.49-53
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• 1988

The perovskite-type compounds $La_{1-x}Ca_xCoO_3$ were synthesized, their thermochemical properties and the gaseous sensitivity were investigated in ethanol vapor. The maximum response for detecting gas corresponded with the exothermic peak of DTA experiment. In any case the substituent was increased, the responsive ratio for detecting gas was grown upon. However, the needed time for response was later, and the operating temperature was elevated. The mechanism of this electrical conductivity was explained by the oxygen ionic diffusion through oxygen vacancy produced by the substituent.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.295-301
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• 1991

The nucleophilic substitution reactions of p-substituted benzenesulfonyl chlorides wiht p-substituted anilines were carried out in 1,1,1,3,3,3-hexafluoro-2-propanol and 2-propanol mixtures. The salt effect was observed to be inhibited by the reaction of 1,1,1,3,3,3-hexafluoro-2-propanol with nucleophiles. To investigate the effectiveness of the salt for the nucleophilic substitution reaction the relative salt effect was determined. According to the comparison with the inhibitive salt effect and the substituent effects for the substrates and nucleophiles, the reactions were predicted to be controlled by the salt effect more than substituent effect in HFP-PrOH mixtures.

• Journal of the Korean Chemical Society
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• v.24 no.6
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• pp.469-472
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• 1980

• Journal of the Korean Chemical Society
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• v.52 no.4
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• pp.369-379
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• 2008

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2005.05a
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• pp.136-138
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• 2005

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.891-895
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• 2000

Transmission of substituent effects through 5-membered heteroaromaticrings isinvestigated theoretically at the RHF/6-31+G* and B3LYP/6-31+G* levelsusing the deprotonation equilibria of phenol analogues with heteroatoms Y = NH, O, PHand S. The incr ease in the resonance delocalization of the $\pilone-pair$ on the phe-nolic oxygen atom, $n\pi(O)$, accompanied with the deprotonation depends on the heteroatom Y,in the order NH < O < PH < S. This represents the $\pielectron$ accepting ability, or conversely reverse order of the $\pielectron$ donating ability of the $\pilone-pair$ on Y, $n\pi(Y).$ The transmission efficiency of substituenteffects is, however,in the reverse order NH > O > S, which represents the order of delocalizability of $n\pi(Y).$ A better correlation is obtained with ${\sigma}p$ - than with ${\sigma}p$ for the Hammett type plots with the positive slope, $\rho-$ > 0, of the magnitude in the same order as that for the delocalizability of $n\pi(Y).$ Thedeprotonation energy, ΔG = [G(PA) + G(H+)] -G(P), decreases with the increasein the extence delocalization in the order NH > O > PH > S.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.839-844
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• 1995

The kinetics and mechanism of the reactions of phenyl benzoates with benzylamines and pyrrolidine are investigated in acetonitrile. The variations of ρX (ρXY>0) and ρZ (ρYZ<0) with respect to the substituent in the substrate (σY) indicate that the reactions proceed through a tetrahedral intermediate, T±, with its breakdown in the rate determining step. The large magnitudes of ρZ, ρXY and ρYZ as well as the effects of secondary kinetic isotope effects involving deuterated nucleophiles are also in line with the proposed mechanism.