• Journal of the Korean Chemical Society
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• v.53 no.2
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• pp.202-206
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• 2009

• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.864-872
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• 1994

Absorption spectra of thermochromic spiropyran and spirooxazine derivatives were investigated. The effects of solvent polarity on the absorption spectra indicate that the merocyanine-like form of non-substituted spiro compound is likely to the quinoid type. However, the merocyanine-like form of electron-withdrawing substituted spiro compound is likely to the zwitter-ion type. The enthalpy changes between the closed and merocyanine-like forms were measured. The enthalpy change of spiro compound decreases as the solvent polarity increases. The UV-Vis spectrum of merocyanine-like form was resolved into three Lorentzian-Gaussian product bands. The solvent dependence of the amount of the three band was also examined.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.500-505
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• 2010

Two different dyes containing the same molecular weight but different chemical structure have been utilized for the study of thermodynamic parameters. In this study, {3-(4-(diethylamino)phenyl)-3-(1-ethyl-2-methyl-1H-indol-3-yl)isobenzofuran-1(3H)-one} (Blue 502) and {3-(4-(diethylamino)-2-methylphenyl)-3-(1,2-dimethyl-1H-indol-3-yl)isobenzofuran-1(3H)-one} (Blue 402) were used. It has been performed by measuring UV spectra of the two dyes. In general, the blue shift has been observed from both dyes in higher carbon number alcohol solvents. Interestingly, Blue 502 showed higher stability than Blue 402 in the same conditions used in this study. And, the equilibrium constants (0.9~1.0) of the dyes depending upon temperature change were also calculated using UV absorbance. The standard enthalpy calculated from equilibrium constants and molar absorptivity($\varepsilon$) are 10.94 kJ/mol in Blue 402 and 9.010 kJ/mol in Blue 502, respectively.

• Archives of design research
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• v.21
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• pp.99-106
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• 1997

There were the changes of shapes and color tones when the soil materials e.g. Blue-Porcelain, White-Porcelain, Bunchong, mixed A and B, mullite, Sanchong and Ongki - used by most domestic ceramic artists - were glazed at $ 950^{\circ}C,; 1200^{\circ}C,; 1250^{\circ}C,; 1280^{\circ}C,;1300^{\circ}C$ After the materials were dried out at 120t: in an electric oven, they were mixed with water, keeping the percentage of moisture content 25% and kneaded specimens which are hexahedron by $$ 250{\times}30{\times}8mm$$were produced and dried after calibrated at 200mm interval with a vernier caliper. After the materials were dried and glazed, they showed few shape-changes at $950^{\circ}C$ but began to changed at $1200^{\circ}C$,especially Bunchong and Ongki made rapid changes. In the case of color-change, White-Porcelain changed very little. The color of Blue-Porcelain, mixed A and B, Sanchong, Mullite changed to ]aune brilliant as temperature went up but Bunchong and Ongki changed to dark brown or dark chocolate under the same conditions. This study aims at suggestion of the basic data which minimize failure rates by recognizing the property of the materials on the basis of this study and regulating shape-change phenomena and sensitive changes of color when ceramic artists work.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.141-148
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• 2019

Electronic substrates used in a mobile device is composed of various materials, and when the temperature is changed during manufacturing or operating, thermal deformation and stress concentration occur due to the difference in thermal expansion coefficient of each material. The shadow moiré technique is a non-contact optical method that measures shape or out-of-plane displacement over the entire area, but it is necessary to overcome the Talbot effect for high sensitivity applications. In this paper, LED light sources of various wavelengths was used to overcome the Talbot effect caused in the shadow moiré technique. By using the phase shift method, an experimental method to retain the measurement sensitivity within 10 ㎛/fringe was proposed and evaluated, and this method is applied to the thermal deformation measurement of the mobile electronic substrate. In the case of using white light, there were several areas that could not be measured due to the Talbot effect, but in the case of using blue LED light, it was shown that a precise moiré pattern with a sensitivity of 6.25 ㎛/fringe could be obtained in most areas.

• Analytical Science and Technology
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• v.22 no.2
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• pp.159-165
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• 2009

The thermochromism of fluoran has been examined. The DCF exists as a colorless lactone in aprotic solvents. However, the DCF exists in the form of an equilibrium mixture of a colored zwitter-ion and a colorless lactone in protic solvents. When an acid is added to the solution, the DCF exists an equilibrium mixture as a colorless lactone and a colored cation even in aprotic solvents. In order to understand the interaction between the DCF and the solvent, absorption spectra of the DCF in various solvents were measured. The thermodynamic parameters of the DCF have also been investigated. From the variation of absorbance with temperature, the standard enthalpy changes ${\Delta}H^0$ of the equilibrium between the lactone and the zwitter-ion in various solvents have been determined. The standard enthalpy change ${\Delta}H^0$ is approximately -2.0 kJ/mol in protic solvents. In acidic solution, the standard enthalpy change is measured to be to zero in protic solvents within the experimental error. When the carboxylic group is protonated in acidic solution, a poor interaction between the dye and the solvent is expected.