• Bulletin of the Korean Chemical Society
• /
• v.14 no.4
• /
• pp.425-427
• /
• 1993

• Bulletin of the Korean Chemical Society
• /
• v.11 no.5
• /
• pp.362-364
• /
• 1990

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.11a
• /
• pp.48.1-48.1
• /
• 2009

Performance of organic field-effect transistors (OFETs) with various temperature-cured polyacrylate(PA) copolymer as a gate insulator was studied. The PA thin film, which was cured at an optimized temperature, showed high dielectric strength (>7 MV/cm), low leakage current density ($5{\times}10^{-9}\;A/cm^2$ at 1 MV/cm) and enabled negligible hysteresis in MIS capacitor and OFET. A field-effect mobility of ${\sim}0.6\;cm^2/V\;s$, on/off current ratio (Ion/Ioff) of ${\sim}10^5$ and inverse subthreshold slope (SS) as low as 1.22 V/decwere achieved. The high dielectric strength made it possible to scale down the thickness of dielectric, and low-voltage operation of -5 V was successfully realized. The chemical changes were monitored by FT-IR. The morphology and microstructure of the pentacene layer grown on PA dielectrics were also investigated and correlated with OFET device performance.

• Macromolecular Research
• /
• v.17 no.6
• /
• pp.436-440
• /
• 2009

We improved the performance of pentacene-based thin film transistors by changing the curing environment of poly(4-vinylphenol) (PVP) gate dielectrics, while keeping the dielectric constant the same. The field-effect mobility of the pentacene TFTs constructed using the vacuum cured PVP was higher than that of the device based on the Ar flow cured gate dielectric, possibly due to the higher crystalline perfection of the pentacene films. The present results demonstrated that the curing conditions used can markedly affect the surface energy of polymer gate dielectrics, thereby affecting the field-effect mobility of TFTs based on those dielectrics.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2005.05a
• /
• pp.1-14
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• v.35 no.4
• /
• pp.1057-1060
• /
• 2014

In our previous articles, an approach has been proposed for the evaluation of the uncertainty of overall result from multiple measurements. In the approach, uncertainty sources were classified into two groups: the first including those giving same 'systematic' effect on each individual measurement and the second including the others giving 'random' effect on each individual measurement and causing a variation among individual measurement results. The arithmetic mean of the replicated measurements is usually assigned as the value for the overall result. Uncertainty of the overall result is determined by separately evaluating and combining an overall uncertainty from sources of the 'systematic' effect and another overall uncertainty from sources of the 'random' effect. This conceptual approach has been widely adopted in chemical metrology society. In this study, further logical proof with more detailed mathematical expressions is provided on the approach.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.3
• /
• pp.166-173
• /
• 2007

A numerical study was conducted to have the effect of $CO_2$ addition to fuel on the chemical reaction mechanism with the change of the initial concentration of $CO_2$ and the axial velocity gradient. From this study, it was found that there were two serious effects of $CO_2$ addition on a non-premixed flame ; a diluent effect by the reactive species reduction and chemical effect of the breakdown of $CO_2$ by the third-body collision and thermal dissociation. Especially, the chemical effect was serious at the lower velocity gradient of the axial flow. It was certain that the mole fraction profile of $CO_2$ was deflected and CO was increased with the initial concentration of $CO_2$. It was also ascertained that the breakdown of $CO_2$ would cause the increasing of CO mole fraction at the reaction region. It was also found that the addition of $CO_2$ did not alter the basic skeleton of $H_2-O_2$ reaction mechanism, but contributed to the formation and destruction of hydrocarbon products such as HCO. The conversion of CO was also suppressed and $CO_2$ played a role of a dilution in the reaction zone at the higher axial velocity gradient.

• Geomechanics and Engineering
• /
• v.11 no.3
• /
• pp.373-383
• /
• 2016

As one natural material, the physical and mechanical properties of rock will be affected very largely by chemical erosion environment. Under chemical environment, the strength of rock will be reduced. Considering the effect of the chemical erosion, fracture factor of rock is reduced. The damage variable is applied to express the change of fracture stress. Therefore, the fracture criterion of rock under chemical environment is constructed. By one experiment of rock fracture under chemical erosion environment, the proposed fracture criterion is verified. The results show that, the fracture path by theory is agree with the testing one well.

• Transactions on Electrical and Electronic Materials
• /
• v.4 no.3
• /
• pp.25-28
• /
• 2003

Radiation technology is an effective way for regulating polymeric materials to physicochemical and mechanical properties. New polymeric hydrogels based on vinyl ethers have been synthesized by the $\gamma$-initiated polymerization method. In this paper, we have studied the effect of radiation on mechanical and electrochemical properties of new rubber-like polymeric composite materials based on polyvinylether of ethyleneglycol (PVEEG).

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.147-148
• /
• 2005

We report on high-performance organic field-effect transistors by promoting surface-mediated two-dimensional molecular ordering in organic semiconductor. To achieve this goal, we have controlled the intermolecular interaction at the interface between organic semiconductor and the insulator substrate.