• Korean Membrane Journal
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• 제4권1호
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• pp.20-24
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• 2002

The surface of polysulfone membranes has been modified using the fluorine chemicals, ITFE (2-iodo-1,1,1-trifluoro-ethane F.W.=209.94) and PFPI (1H,1H-pentafluoro-n-propyl iodide F.W.=259.95), and PFI (1H,1H,2H,2H-perfluorohexyl iodide, F.W.=373.99) based on Friedel-Crafts reaction mechanism with varying reaction temperatures, reaction time, and catalysis types. The resulting membranes were characterized through mainly the contact angle measurement and pure water permeability. The smaller reactant shows the larger contact angles. FeBr$_3$ catalyst is more effective than AlCl$_3$. Typically, the PS film treated with ITFE at $25^{\circ}C$ under FeBr$_3$ catalyst showed the contact angle 78.5$^{\circ}C$ which indicated 10% over the value of unreacted PS films. More than 50% of pure water flux 8.0 g/$m^2$hr, reduced at reaction time 10 min relative to the original flux, 3.49 g/$m^2$hr.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.90-93
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• 1997

고주파 반응성 스퍼터링 방법을 사용하여 희토류가 첨가된 SiO$_2$ 박막을 제작하여 특성을 조사하여, 양질의 희토류 원소가 첨가된 SiO$_2$ 박막의 최적의 제작조건을 도출하고 Er-Al:SiO$_2$ 박막의 소자웅용 가능성에 대하여 조사하였다 열처리전의 Er의 농도는 EDS(Energy dispersing x-ray spectrometer)로 측정한 결과 0.77% 로 농도를 나타내었고 코아층 첨가된 Er은 균일하게 분포되었다 크레드층의 굴절률은 633nm의 파장에서 측정하였을때 1.458이였고 코아층의 굴절률은 동일 파장에서 1.757이였다. 굴절률 분포도 (Refractive Index Profile)는 계단형 굴절률 분포로 코아층/클래드 굴절률 차 $\Delta$n$_{ESI}$ = 0.1였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.287-290
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• 2000

We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 20[mN/m]. LB layers of Arac. acid deposited by LB method were deposited onto y-type silicon wafer as x, y, z-type film. In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/arachidic acid/Al, the number of accumulated layers. Also, we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from 0 to +2[V].

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1865-1867
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• 2005

Film bulk acoustic resonator (FBAR) devices which adopt an air-gap type (metai/AlN/metal/air/substrate) configuration are fabricated by a novel process. The newly fabricated resonator doesn't employ any supporting layer below it. FBAR devices with the air-gap type are also fabricated using the conventional method. The frequency response characteristics of all the devices fabricated are measured and compared, in terms of the kinds of top and bottom electrode materials. The results show that the better device performance of FBAR devices can be achieved by employing the proposed process.

• 한국전기전자재료학회논문지
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• 제14권11호
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• pp.922-927
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• 2001

Single-layer green ELs was fabricated with using molecularly-dispersed Bu-PBD into poly-N-vinylcarbazole(PVK) which has low operating voltage and high quantum efficiency. A EL cell structure of glass substrate/indium-tin-oxide/PVK:Bu-PBD:C6(∼ 100nm)/Ca(20nm)/Al(20nm) was employed with variable doping concentration. The keys to obtain high quantum efficiency was excellent film forming capability of molecularly dispersed into PVK and appropriate combination of cathode for avoiding exciplex. We obtained the turn-on voltage of 4.2V and quantum efficiency of 0.52% at 0.lmol% of C6 concentration which has been improved about a factor of 50 in comparison with the undoped cell. The PL peak wavelengths wouldn\`t be turned by changing the concentration of the C6 dopant. Green EL emission peak and FWHM were 520nm and 70nm respectively. PL emission peak was obtained at 495nm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.831-834
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• 2000

Characteristics of organic light-emitting diodes(OLEDs) were studied with devices made by PECCP[poly(3,6-N-2-ethylhexyl carbazolyl cyanoterephthalidene)] Langmuir-Blodget(LB) films. The emissive organic material was synthesized and named PECCP, which has a strong electron donor group and an electron accepter group in main chain repeated unit. The LB technique was employed to investigate the identification of the recombination zone in the ITO/PECCP LB films/Alq$_3$/Al structure by varying the LB film thickness. PECCP was considered as an emissive layer and Alq$_3$was used as an electron-transport layer. We measured current-voltage(I-V) characteristics, UV/visible absorption, PL spectrum, and EL spectrum of those devises.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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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.

• 열처리공학회지
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• 제34권6호
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• pp.281-286
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• 2021

Arc ion plating (AIP), laser cladding, and nitriding are methods that can prevent mold damage or repair and create cracks and breakages on the die surface. The dissolution and soldering behavior of coated SKD61 by using arc ion plating, laser cladding, and nitriding was investigated. The structure of the coating was investigated as a function of deposition conditions by X-ray diffraction and the crystallographic orientation was determined using the texture factor. The TiAlN film deposited with AIP showed excellent corrosion resistance in the molten aluminum alloy at 680℃. In this paper, we have detailed the corrosion and mass loss phenomena associated with these steel-cast metal interactions.

• Journal of Periodontal and Implant Science
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• 제30권1호
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• pp.187-203
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• 2000

The precipitation of calcium phosphate on implant surface has been known to accelerate osseointegration and to enhance osseous adaptation. The present study was performed to examine whether the precipitation of calcium phosphate on Ti-6Al-4V alloy could be affected by the immersion in NaOH solution and heat treatment. Ti-6Al-4V alloy plates of $15{\times}3.5{\times}1mm$ in dimension were polished sequentially from #240 to #2,000 emery paper and one surface of each specimen was additionally polished with $0.1{\mu}m$ alumina paste. Polished specimens were soaked in various concentrations of NaOH solution(0.1, 1.0, 3.0, 5.0, 7.0, 10.0 M) at $60^{\circ}C$ for 24 hours for alkali treatment, and 5.0 M NaOH treated specimens were heated for 1 hour at each temperature of 400, 500, 600, 700, $800^{\circ}C$. After the alkali and heat treatments, specimens were soaked in the Hank's solution with pH 7.4 at $36.5^{\circ}C$ for 30days.The surface ingredient change of Ti-6Al-4V alloy was evaluated by thin-film X-ray diffractometer(TF-XRD) and the surface microstructure was observed by scanning electron microscope(SEM), and the elements of surface were analyzed by X-ray photoelectron spectroscopy(XPS). The results were obtained as follows ; 1. The precipitation of calcium phosphate on Ti-6Al-4V alloy was accelerated by the immersion in NaOH solution and heat treatment. 2. In Alkali treatment for the precipitation of calcium phosphate on Ti-6Al-4V alloy, the optimal concentration of NaOH solution was 5.0 M. 3. In heat treatment after alkali treatment in 5.0 M NaOH solution, the crystal formation on alloy surface was enhanced by increasing temperature. In heat treated alloys at $600^{\circ}C$, latticed structure and prominences of calcium phosphate layer were most dense. On heat treated alloy surface at the higher temperature(${\geq}700^{\circ}C$), main crystal form was titanium oxide rather than apatite. The above results suggested that the precipitation of calcium phosphate on the surface of Ti-6Al-4V alloy could be induced by alkali treatment in 5.0 M-NaOH solution and by heat treatment at $600^{\circ}C$.

• Progress in Superconductivity
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• 제14권1호
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• pp.30-33
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• 2012

We have grown $MgB_2$ superconducting thin films on the SiC buffer layers by means of hybrid physical-chemical vapor deposition (HPCVD) technique. Prior to that, SiC was first deposited on $Al_2O_3$ substrates at various temperatures from room temperature to $600^{\circ}C$ by using the pulsed laser deposition (PLD) method in a vacuum atmosphere of ${\sim}10^{-6}$ Torr pressure. All samples showed a high transition temperature of ~40 K. The grain boundaries of $MgB_2$ samples with SiC layer are greater in amount, compare to that of the pure $MgB_2$ samples. $MgB_2$ with SiC buffer layer samples show interesting change in the critical current density ($J_c$) values. Generally, at both 5 K and 20 K measurements, at lower magnetic field, all $MgB_2$ films deposited on SiC buffer layers have low $J_c$ values, but when they reach higher magnetic fields of nearly 3.5 Tesla, $J_c$ values are enhanced. $MgB_2$ film with SiC grown at $600^{\circ}C$ has the highest $J_c$ enhancement at higher magnetic fields, while all SiC buffer layer samples exhibit higher $J_c$ values than that of the pure $MgB_2$ films. A change in the grain boundary morphologies of $MgB_2$ films due to SiC buffer layer seems to be responsible for $J_c$ enhancements at high magnetic fields.