• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.424-430
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• 2011

A novel T-type polyurethane 7 containing 1-(2,5-dioxyphenyl)-2-(5-(1,2,2-tricyanovinyl)-2-thienyl)ethenes as NLO chromophores, which constitute part of the polymer backbone, was prepared. Polyurethane 7 is soluble in common organic solvents such as DMF and DMSO. It shows a thermal stability up to $270^{\circ}C$ from TGA thermogram with $T_g$ value obtained from DSC thermogram near $155^{\circ}C$. The second harmonic generation (SHG) coefficient ($d_{33}$) of poled polymer film at 1560 nm fundamental wavelength is $3.56{\times}10^{-9}$ esu. Polymer 7 exhibits a thermal stability even at $5^{\circ}C$ higher than $T_g$, and no significant SHG decay is observed below $160^{\circ}C$, which is acceptable for nonlinear optical device applications.

• Journal of the Korean Home Economics Association
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• v.19 no.2
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• pp.213-221
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• 1981

This theiss deals with the effects of addition of silicone oil to the polymerization and oxidation of frying oil in the practical deep fat frying process. The measurement of frying oil stability was carried out under various silicone oil content and compared with controlled frying process. In controlled frying process A.V., C.O.V., TBA, and contents of petroleumether insoluble fatty acids were increased as time was increased. It means thermal oxidized polymerization and hydrolysis of frying oil was occurred. When silicone oil was added to frying oil, it's thermal stability was better than that of the controlled oil and the degree of thermal stability was changed according to the contents of silicone oil. We obtained the highest degree of thermal stability when silicone oil was added 1ppm.

• Textile Coloration and Finishing
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• v.33 no.4
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• pp.169-181
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• 2021

Five dyes based on phthalocyanine, a dye on azo, and a dye on anhraquinone were prepared from corresponding starting material to investigate the effects of substituent on thermal-stability of dyes which is essentially required to apply to the color filters. Synthesized dyes were confirmed their chemical structure using by 1H-NMR, MASS and Elemental analysis. The thermal-stability was evaluated by the weight reductions measured by TGA analysis comparing to that of conventional C.I. Pigment Blue 15:6. The absorption maxima were measured by UV-VIS spectrophotometer then the effects of substituent on absorption maximum was also investigated.

• Wind and Structures
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• v.32 no.1
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• pp.31-46
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• 2021

The current research deals with, stability/instability and cylindrical composite nano-scaled shell's resonance frequency filled by graphene nanoplatelets (GPLs) under various thermal conditions (linear and nonlinear thermal loadings). The piece-wise GPL-reinforced composites' material properties change through the orientation of cylindrical nano-sized shell's thickness as the temperature changes. Moreover, in order to model all layers' efficient material properties, nanomechanical model of Halpin-Tsai has been applied. A functionally modified couple stress model (FMCS) has been employed to simulate GPLRC nano-sized shell's size dependency. It is firstly investigated that reaching the relative frequency's percentage to 30% would lead to thermal buckling. The current study's originality is in considering the multifarious influences of GPLRC and thermal loading along with FMCS on GPLRC nano-scaled shell's resonance frequencies, relative frequency, dynamic deflection, and thermal buckling. Furthermore, Hamilton's principle is applied to achieve boundary conditions (BCs) and governing motion equations, while the mentioned equations are solved using an analytical approach. The outcomes reveal that a range of distributions in temperature and other mechanical and configurational characteristics have an essential contribution in GPLRC cylindrical nano-scaled shell's relative frequency change, resonance frequency, stability/instability, and dynamic deflection. The current study's outcomes are practical assumptions for materials science designing, nano-mechanical, and micromechanical systems such as micro-sized sensors and actuators.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.439-442
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• 2004

In this study, we investigated about electrooptics characteristic of three kinds of TN cell on the polyimide surface. Monodomain alignments of thermal stressed TN cell over temperature of liquid crystal isotropic phase were almost the same as that of no thermal stressed TN cells. However, the thermal stressed TN cells have many defects. Also, threshold voltage and response time of thermal stressed TN cells show the same performances as no thermal stressed TN cells. There were little changes of value in these TN cells. However, transmittances of TN cells on the polyimide surface decrease with increasing thermal stress time. Finally, the residual DC voltage of the thermal stressed TN cell on the polyimide surface shows decrease of characteristics as increasing thermal stress time. Therefore, the thermal stability of TN cell was decreased by high thermal stress for the long times.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.205-208
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• 2002

Thermal design is required with considering thermal stability to verify the reliability of electric power device with using IGBT. Numerical analysis is performed to analyzed the change in thermal resistance with respect to the various thermal density of heating element. Correlations between thermal resistance and heat generation density are established. With using these correlations, performance curve is composed with respect to the change in thermal resistance of cooling conditions for natural convection and forced convection. Thermal fatigue is occurred at the Inside and outside of IGBT by repeated heat load. The crack is occurred between base plate and ceramic substrate for the inside. When the crack length is 4mm, the failure is occurred. Therefore, Thermal design method considering thermal density, thermal fatigue resistance is presented on this study and it is expected to thermal design with considering life prediction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.287-288
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• 2005

In this study, we have investigated electro-optical characteristics of thermal and UV stressed TN cells on the rubbed polyimide surface. Mono-domain alignments of thermal stressed TN cells over temperature of liquid crystal isotropic phase were almost same that of no thermal stressed TN cells. Also, threshold voltage and response time of thermal stressed TN cells were same that of no thermal stressed TN cells. Finally, the residual DC voltage of the thermal stressed TN cell on the polyimide surface show decrease of characteristics as increasing thermal stress time. Therefore, thermal stability of TN cell was decreased by high thermal stress for the long times.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1033-1036
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• 2006

We have investigated electro-optical characteristics in three kinds of twisted nematic (TN) cells on the polyimide surface. The threshold voltage and the response time of thermal stressed TN cells were same that of no thermal stressed TN cells. There were little change of value in these TN cells. On the other hand, transmittance of no thermal stressed TN cells were better than that of thermal stressed TN cells. Transmittances of TN cells on the polyimide surface decreased by increasing thermal stress time. Moreover, the residual DC of the thermal stressed TN cells increased as increasing thermal stress temperature and time. Therefore, thermal stability of TN cells were decreased gradually by giving high thermal stress for a long time.

• Journal of Adhesion and Interface
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• v.8 no.4
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• pp.14-22
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• 2007

In the present study, the effect of milled glass powder and liquid-type nitrile rubber (NBR) on the thermal stability of phenolic resin and the dynamic mechanical properties of glass braid/phenolic composites has been investigated by means of thermogravimetric analysis and dynamical mechanical analysis. It was found that both milled glass power and NBR filled in the waterborne phenolic resin significantly influenced the thermal stability of phenolic resins and the storage modulus and tan delta of the composites. The presence of glass powder increased the thermal stability of the phenolic resin, whereas the presence of NBR resulted in the weight loss in the specific temperature range. The thermal stability of the phenolic resins without and with the fillers was dependent not only on the cure temperature but also on the cure time. The variation of the storage modulus and tan ${\delta}$ of strip-type glass braid/phenolic composites was also influenced with the introduction of glass powder and NBR to the phenolic matrix as well as by the cure conditions given.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.12
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• pp.1130-1134
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• 2008

Thermal and electrochemical properties were discussed with tris(2,4,6-trimethoxyphenyl)Phosphine (TTMPP) as a flame retradant additive for Li-ion battery. TTMPP showed excellent thermal stability with charged cathodes. Addition of 1 wt.% of the additive to the electrolyte improved the thermal stability without damaging the performance of the battery. The oxygne evolution reaction delayed nearly by $60^{\circ}C$. The capacity retention ratio in cycle life tests of the battery with 1 wt.% TTMPP was slightly improved comparing to the no additive cells.