• Journal of Integrative Natural Science
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• v.6 no.4
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• pp.211-214
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• 2013

In this study, in order to investigate how consecutive treatments of glass surface with HF acid and water vapor/Ar plasma affect the quality of 3-aminopropyltriethoxysilane self-assembled monolayer (APS-SAM), poly(3,4-ethylenedioxythiophene) (PEDOT) thin films were vapor phase-polymerized immediately after spin coating of FeCl3 and poly-urethane diol-mixed oxidant solution on the monolayer surfaces prepared at various treatment conditions. For the film characterization, various poweful tools were used, e.g., FE-SEM, an optical microscope, four point probe, and a contact angle analyzer. The characterization revealed that HF treatment is not desirable for the synthesis of a high quality PEDOT thin film via vapor phase polymerization method. Rather, sole treatment with plasma noticeably improved the quality of APS-SAM on glass surface. As a result, a highly dense and smooth PEDOT thin film was grown on uniform oxidant film-coated APS monolayer surface.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.967-972
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• 2004

The role of transfer films formed during sliding of polymer composites against steel counterfaces was studied in terms of the tribological behaviors of composites. Four kinds of composites were included in this study: (1) unfilled PPS, (2) PPS+2%CuO, (3) PPS+2%CuO+5% carbon fiber (CF), and (4) PPS+2%CuO+15%Kevlar. The filler material CuO was in nanoscale particulate form and the reinforcing material was in the form of short fibers. The composites were prepared by compression molding at $310^{\circ}C$ and sliding tests were run in the pin-on-disk sliding configuration. The counterface was made of tool steel hardened to 55-60 HRC and finished to a surface roughness of 0.09-0.10 ${\mu}m$ Ra. Wear tests were run for 6 hrs at the sliding speed of 1 m/s and contact pressure of 0.65 MPa. Transfer films formed on the counterfaces during sliding were investigated using AFM and SEM. The results showed that as the transfer film became smooth and uniform, wear rate decreased. PPS+2%CuO+15%Kevlar composite showed the lowest steady state wear rate in this study and its transfer film showed the smoothest and the most uniform characteristics. The examination of worn surfaces of PPS+2%CuO composite using X-ray area scanning (dot mapping) showed back-transfer of steel counterface material to the polymer pin surface. This behavior is believed to strengthen the polymer pin surface during sliding thereby contributing to the decrease in wear rate.

• Journal of radiological science and technology
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• v.4 no.1
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• pp.45-53
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• 1981

In examinations of the stomach roentgenography, it is imperative to obtain adequate film density throughout all its different regions. Therefore, it is necessary to use more sophiscated exposure techniques. In order to achieve these purpose, the radiologic technologists must be measured abdominal thickness in variations with patient positions. In consideration of these problem, the author was made an experiment on correction method of kVp and mAs by abdominal thickness in roentgenography of the stomach. The results were summarized as follws: 1. When the patient in erect position, abdominal thickness was the most thickened at the level of 3cm inferior to umbilicus without regard to body habitus and it was the most thickened at the level of 3cm superior to umbilicus in prone and supine position. 2. As a result of measuring film density for stomach, the adequate film density was represented from 0.70 to 2.49 in erect position and $0.28{\sim}1.18$ in supine position, $0.5{\sim}2.45$ in prone position. 3. In order to obtain uniform film density in 1.25, the correction factor for kVp by abdominal thickness was represented average ${\pm}4.5kVp\;per\;{\pm}1cm$ in a fixed 50 mAs, and average ${\pm}3.9kVp\;per\;{\pm}1cm$ in a fixed 100mAs. 4. In order to obtain uniform film density in 1.25, the correction factor for mAs by abdominal thickness was represented average ${\pm}30.9%\;per\;{\pm}1cm$ in a fixed 80 kvp and ${\pm}26.9%\;per\;{\pm}1cm$ in a fixed 100kVp.

• Nuclear Engineering and Technology
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• v.42 no.6
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• pp.670-679
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• 2010

In this paper, a new approach using a pixel-based correction method was developed to fix the non-uniform responses of flat-bed type scanners used for radiochromic film dosimetry. In order to validate the method's performance, two cases were tested: the first consisted of simple dose distributions delivered by a single port; the second was a complicated dose distribution composed of multiple beams. In the case of the simple individual dose condition, ten different doses, from 8.3 cGy to 307.1 cGy, were measured, horizontal profiles were analyzed using the pixel-based correcton method and compared with results measured by an ionization chamber and results corrected using the existing correction method. A complicated inverse pyramid dose distribution was made by piling up four different field shapes, which were measured with GAFCHROMIC$^{(R)}$EBT film and compared with the Monte Carlo calculation; as well as the dose distribution corrected using a conventional method. The results showed that a pixel-based correction method reduced dose difference from the reference measurement down to 1% in the flat dose distribution region or 2 mm in a steep dose gradient region compared to the reference data, which were ionization chamber measurement data for simple cases and the MC computed data for the complicated case, with an exception for very low doses of less than about 10 cGy in the simple case. Therefore, the pixel-based scanner correction method is expected to enhance the accuracy of GAFCHROMIC$^{(R)}$EBT film dosimetry, which is a widely used tool for two-dimensional dosimetry.

• KSBB Journal
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• v.31 no.4
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• pp.291-299
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• 2016

In this study, Indomethacin, the poorly water soluble drug, was selected and prepared dispersing oral disintegrating films according to the molecular weight of polyethylene glycol (PEG) which are sort of dispersing agents. Also the molecular weight and content of PEG were evaluated effect on the degree of dispersion, physical property and dissolution when making oral dispersing film containing indomethacin to find appropriate condition and suggested guidelines of making oral dispersing film. The appropriate dispersing ratio of the amount of surfactants and dispersing agent were 1% and 4%, also the stability dropped in the PEG molecular weight of 4000 or more. Drying time of oral dispersing film was $90^{\circ}C$ for 10 minutes to 12 minutes that dispersing film's property about flexibility, detachability were very good. The oral dispersion film's content used PEG 400 was $98.6{\pm}0.5%$ and the most uniform. As the molecular weight of PEG increased, dissolution time also increased. On the basis of evaluation parameter, PEG with 400~600 of molecular weight was selected as good dispersing agent in oral dispersing film. Therefore, it can be suggested guideline of preparation application study in oral dispersing film.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.709-714
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• 1997

$TiO_2$ hydrate coating on mica in an aqueous solution of $TiOSO_4$ by the hydrolysis using ammonia water studied with emphasis on coating conditions for a uniform coating. For the uniform coating of $TiO_2$ film on mica surface, it was found that smaller mica particles were coated more uniformly compared to larger particles. It was necessary to suppress the rate of formation of hydrated $TiO_2$ particles in solution, which were deposited on mica and generate irregular coating. It was also necessary to control precipitation yield by varying the reaction temperature to obtain uniform coating. More uniform coating was obtained with higher precipitation yield. A uniform dense film was formed when mica particles of average size of $14.7{\mu}m$ is used for mica slurry solution, of which pH is 2.5, and the factor of acidity of $TiOSO_4$ solution is 291, and the solution was kept at $80^{\circ}C$ for 3 hours. The morphology of $TiO_2$ film formed on mica was little affected by firing at $900^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1463-1465
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• 2008

We report all-ink-jet printed inorganic/organic hybrid TFTs on plastic substrates. We have investigated the optimal printing conditions to make uniform patterned layers of gate electrode, dielectrics, source/drain electrodes, and semiconductor as a coplanar type TFT in a successive manner. All ink-jet printed devices have good mechanical flexibility and current modulation characteristic even when bent.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.819-820
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• 2008

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.437-443
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• 1999

This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate subjected to uniform temperature change. The viscoelastic film has been assumed to be thermorheologically simple. The time-domain boundary element method(BEM) has been employed to investigate the behavior of interface stresses. The order of the free-edge singularity has been obtained numerically for a given viscoelastic model. It is shown that the free-edge stress intensity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.274-277
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• 2007

In this study, liquid crystal(LC) aligning capabilities for homeotropic alignment on the $SiO_x$ thin film by electron beam evaporation method were investigated. Also, the control of pretilt angles and thermal stabilities of the nematic liquid crystal(NLC) treated on $SiO_x$ thin film were investigated. A high pretilt angle of about $86.5^{\circ}$ was obtained, and also the suitable pretilt angle of the NLC on the $SiO_x$ thin film at $10{\sim}50nm$ thickness with e-beam evaporation can be achieved. The uniform LC alignment and good thermal stabilities on the $SiO_x$ thin film surfaces with electron beam evaporation can be achieved. It is considered that the LC alignment on the $SiO_x$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_x$ thin film surface created by evaporation.