• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.116-119
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• 1997

In this paper A double-layer organic electroluminescent(EL) device was fabricated using a TPD(N,N'-dipheny] -N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4.4'-diamine: aromatic diamine), as a hole-transport material and tris (8-hydroxy quinolinate) aluminum(Alq$_3$) as a an emiting material and its performance characteristics were investigated. structure of devices is ITO/TPD/Alq$_3$/Al. we have fabricated hole transport layer of two types. Doping material of Hole Transport material is Poly(methyl methacrylate)(PMMA) and PEI(Poly-Ether-Imide). Carrier injection from the electrodes to the doped PMMA and PEI layer through the dopants and concomitant electroluminescence from Alq$_3$were observed. Green emission with luminance of 40cd/m$^2$was achieved at a drive voltage of 30V

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.103-107
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• 1994

An experimental study was carried out to investigate the fabrication process and electrical breakdown of electrodeposted polyimide film from nonaqueous emulsion onto metal electrode surface. The thickness of imide film control led by the deposition voltage and time are proportional to the voltage or time. From the results, yeilds is proportional to the total elctrical charge flow through the electrode. When electrophoretic deposition voltage is 30 [V] deposition time is 30 sec, 40 sec, 50 sec, then the thickness of the films are 2.13 $\mu\textrm{m}$, 2.69 $\mu\textrm{m}$, 3.16 $\mu\textrm{m}$, 3.94 $\mu\textrm{m}$, respectively Electrical breakdown voltage of polyimide thin film shows very high. As film thicknes increase, the breakdown voltage are increased, but are net directly proprotional to thickness of the film.

• Textile Coloration and Finishing
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• v.16 no.5
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• pp.35-41
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• 2004

Poly(ethylene terephthalate), polyimide(Kapton), and polypropylene surfaces were modified with argon low temperature plasma by RF glow discharge at 240m Torr, 40W to investigate the surface morphological changes due to the plasma treatment using atomic force microscopy(AFM). Analysis of the AFM images and Ra(average roughness) revealed that the plasma treatment resulted in significant ablation on the surfaces. The morphological changes and surface roughness, however, were different depending on material characteristics such as heat stability, presence of amorphous region, swelling phenomenon, and molecular structure of repeating unit. It was assumed that polypropylene due to its tertiary hydrogen was ablated easily compared to poly(ethylene terephthalate), and that polyimide was more resistant to the ablation than PET due to rigid skeleton of imide and stable phenyl ring structure.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.166-168
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• 2007

스퍼터링법으로 제작된 FCCL은 PI필름(Poly-imide film)과 Cu layer사이에 Tie-coating layer로 Ni-Cr을 많이 사용한다. 하지만 완성된 FCCL에서 페터닝을 실시할 때 Cr성분이 소멸되지 않고 잔존하는 현상으로 누설전류가 발생 한다. 또한 Cr으로 인해 Eatching액의 오염으로 재사용의 어려움도 발생된다. 이러한 원인들은 제품의 특성들을 저하 시키므로 이를 개선할 필요가 있다. 따라서 본 연구에서는 기존의 Tie-coating layer를 대체할 물질로 Acrylic acid를 이용하여 FCCL을 제작하여 표면특성 평가를 위해 Contact angle측정과 부착력을 위한 Peel test측정과 조직분석 및 성분분석을 위해 SEM-EDS를 측정을 통하여 Polymerization을 이용한 Ti-coating layer 개발의 가능성을 확인하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.169-172
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• 2005

공정시 플라스틱 기판의 변형을 방지하기 위해 PC(Polycarbonate) 기판을 약 12시간 동안 pre-annealing시킨 다음 SiN(silicon nitride)와 PI(Poly-imide)를 각각 Sputter와 Spin-Coater를 이용하여 Coating하였다. 완성된 PC 기판위에 Themal Evaporation으로 Calsium을 증착한 뒤 Al을 올렸다. Calsium 증착 된면에 삼성 코닝의 글래스를 UV resin으로 부착 시킨 다음 상온에서 투습률을 측정하였다. 측정 간격은 12시간으로 하였으며 Calsium Test 의 정확도 향상을 위해 CCD Camera로 측정하여 컴퓨터로 분석하였다. 그래픽 저장 파일은 저장시 이미지 손실을 방지하기 위해 Bitmap방식을 그대로 사용 하였으며 정확도 향상을 위한 분석 프로그램은 MicroSoft 사의 Visual C++로 작성하였다. 화상 처리 면적은 컴퓨터 시스템의 처리 속도를 감안하여 70*70 으로 하였다.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.493-498
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• 1995

Ultrathin networks of itaconic acid copolymers and poly(allylamine) were produced by a Langmuir-Blodgett (LB) technique employing a double-chain amine as a monolayer template which was subsequently removed by extraction after thermal crosslinking. Itaconic acid copolymers used were copoly (itaconic acid-ethyl vinyl ether) and copoly (itaconic acid-n-butyl vinyl ether). The polyion-complexed monolayers of three components consisting of template amine, itaconic acid copolymer and poly (allylamine) were formed at the air-water interface. The Langmuir film properties have been studied by the surface pressure-area isotherm and fluorescence microscopy. The monolayers were transferred on solid substrates and were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). Two-dimensional polymer networks were formed through imide or amide linkages by heat treatment under vacuum. The heat-treated films were extracted with chloroform after immersion in aq. sodium chloride to remove the template amines. SEM observation of a LB film on a porous fluorocarbon membrane filter with pore diameter of 0.1 μm showed covering of the pores by six layers in the polyion complex state.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.457-464
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• 2020

In this study, extraction of uranium(VI) from an aqueous nitric acid solution was investigated using tri-n-butyl phosphate (TBP) as an extractant in an ionic liquid, 1-alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([Cnmim][Tf2N]). The distribution ratio of U(VI) in 1.1 M TBP/[Cnmim][Tf2N] was significantly high when the concentration of nitric acid was low. The value of the distribution ratio decreased as the concentration of the nitric acid increased at lower acidities, and then increased with a nitric acid concentration of up to 8 M. This can be attributed to the different extraction mechanisms of U(VI) based on nitric acid concentrations. Thus, a cation exchange at low acidity levels and an ion-pair extraction at high acidity levels were suggested as the extraction mechanism of U(VI) in the TBP/[Cnmim][Tf2N] system.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.171-176
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• 2009

Purpose : To investigate the effect of coating material in RF coil, which is one of main parts in MRI machine, on the Q-factor and SNR(signal-to-noise ratio) in MR images. Materials and Methods : RF coils with inner diameter of 1.7 mm were made by using copper wires coated with polyester, polyurethane, polyimide, polyamideimide, and polyester-imide, and by using copper wires in which coating materials had been removed. Q-factors of the RF coils were measured by network analyzer, and SNR values in the spin-echo MR images obtained by 600 MHz (14.1 T, Bruker DMX600) micro-imaging system for the coated and uncoated cases. Results : The measured SNRs were almost same for the RF coils with coat-removed copper wires, however SNRs and Q-factors were different for the coated cases depending on the coating material. They were maximized in the polyurethane-coated case in which the SNR was > 30% greater than polyester-coated case. Conclusion : We made solenoid-type RF coils which were easily used for MR micro-imaging in Bruker MRI probe. There was a significant coating-material dependence in the measured Q values and SNRs for the home-made RF coils. The study demonstrated that the choice of coating material of RF coil may be a critical factor in the MRI sensitivity based on SNR value.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.3
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• pp.347-357
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• 2018

The applicability of room temperature ionic liquids (RTILs), 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([$C_nmim$] [$Tf_2N$]), was investigated for the extraction of Am(III) and Eu(III) from nitric acid using n-octyl(phenyl)-N,N-diisobutyl carbamoylmethyl phosphine oxide (CMPO) and tri-n-butylphosphate (TBP) as extractants. The distribution ratios of Am(III) and Eu(III) in CMPO-TBP/[$C_nmim$][$Tf_2N$] were measured as a function of various parameters such as the concentrations of nitric acid, CMPO, and TBP. The results were compared with those obtained in CMPO-TBP/n-dodecane (n-DD). With comparable concentrations of the extractants, the distribution ratios obtained with RTILs were much higher than those obtained with n-DD. It was observed that the extraction efficiency was less for Eu(III) than for Am(III). The extraction of Am(III) and Eu(III) decreased with increases in the feed acidity for all three RTILs. The results suggest that the extraction of Am(III) and Eu(III) by CMPO in RTILs from nitric acid proceeds through the cation-exchange mechanism. The distribution ratios of Am(III) and Eu(III) increased with increases in the concentration of CMPO for all three RTILs. A linear regression analysis of the extraction data resulted in a straight line with a slope of about 3, suggesting the involvement of 3 molecules of CMPO during the extraction process.

• Membrane Journal
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• v.23 no.5
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• pp.332-342
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• 2013

In the present study, carbon molecular sieve (CMS) hollow fiber membranes were prepared by carbonizing a methyl imide hollow fiber precursor, which was spun by non-solvent induced phase separation process. And effects of carbonization parameters such as pre-oxidation, pyrolysis, and post-oxidation on the gas permeation were systematically investigated. CMS membrane having the highest gas flux was obtained by carbonizing the precursor through a combined process of air pre-oxidation at $250^{\circ}C$ for 2h, nitrogen pyrolysis at $550^{\circ}C$ for 2h, and oxygen post-oxidation at $250^{\circ}C$ for 2h. The optimized membrane showed a considerable gas permeance : the $H_2$, He, $CO_2$ permeances were 69.72, 35.61, 31.01 GPU, respectively, and the $O_2$ and $N_2$ permeances were ignorable. Therefore, it was clear that the prepared CMS hollow fiber membrane was a promising membrane for recovering small gases such as hydrogen and hellium and carbon dioxide.