• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.603-609
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• 2013

In this paper, we describe the analysis of inkjet-printed silver (Ag) patterns on epoxy-coated substrates according to several reliability evaluation test method guidelines for conventional printed circuit boards (PCB). To prepare patterns for the reliability analysis, various regular test patterns were created by Ag inkjet printing on flame retardant 4 (FR4) and polyimide (PI) substrates coated with epoxy for each test method. We coated the substrates with an epoxy primer layer to control the surface energy during printing of the patterns. The contact angle of the ink to the coated epoxy primer was $69^{\circ}$, and its surface energy was 18.6 $mJ/m^2$. Also, the substrate temperature was set at $70^{\circ}C$. We were able to obtain continuous line patterns by inkjet printing with a droplet spacing of $60{\mu}m$. The reliability evaluation tests included the dielectric withstanding voltage, adhesive strength, thermal shock, pressure cooker, bending, uniformity of line-width and spacing, and high-frequency transmission loss tests.

• Environmental Engineering Research
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• 제16권2호
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• pp.91-96
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• 2011

Limited information is available on the degradation of volatile hydrocarbons determined via the use of plate-inserted photocatalytic reactors. This has led to the evaluation of surface areas of cylindrical continuous-flow photocatalytic reactors for the degradation of three selected aromatic hydrocarbons. Three types of reactors were prepared: a double cylinder-type, a single cylindrical-type without plates and a single cylindrical-type with inserted glass tubes. According to diffuse reflectance, FTIR and X-ray diffraction (XRD) spectroscopy, the surface characteristics of a coated photocatalyst were very similar to those of raw $TiO_2$, thereby suggesting that the coated photocatalyst exhibited the same photocatalytic activity as the raw $TiO_2$. The photocatalytic degradation efficiencies were significantly or slightly higher for the single cylinder-type reactor than for the double cylinder-type reactor which had a greater catalytic surface area. However, for all target compounds, the degradation efficiencies increased gradually when the number of plates was increased. Accordingly, it was suggested that the surface area being enhanced for the plate-inserted reactor would elevate the photocatalytic degradation efficiency effectively. In addition, this study confirmed that both initial concentrations of target compounds and flow rates were important parameters for the photocatalytic removal mechanism of these plate-inserted photocatalytic reactors.

• 한국응용과학기술학회지
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• 제31권2호
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• pp.183-189
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• 2014

내화성 및 내화학성이 우수한 현무암사의 표면에 회분식 방법에 의한 테프론 코팅 연구의 결과를 토대로 연속식 코팅 공정 인자를 도출하기 위한 연구를 수행하였다. 현무암사를 7,5 wt% 트리에톡시트리플루오로실란(TMTFPS)으로 연속적으로 전처리 한 후, 침투제로 0.25 wt% bis(2-ethylhexyl)sulfo succinate (DOS-Na)가 함유된 20 wt% 테프론 수분산액으로 딥 코팅한 후 2 m의 $120^{\circ}C$ 건조 챔버에서 12 m/mim의 속도로 건조한 후 2 m의 $380^{\circ}C$ 소성 챔버에서 40초간 소성하여 최종 $3.4g_f/D$의 인장 강도와 $2.3g_f/D$의 루프강도를 가지는 테프론이 코팅된 고내열 재봉사용 현무암사를 제조하였다.

• 한국결정성장학회지
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• 제33권5호
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• pp.191-195
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• 2023

핸드폰 Backcover에 적용한 3층 나노코팅 필름을 롤투롤(roll-to-roll) 연속 공정을 통하여 제조하였다. 세라믹/금속/세라믹 3층 구조의 코팅층을 도입함으로써 금속 고유의 반사 특성을 유지하면서 전기적으로는 절연 특성을 유지하였다. 길이와 폭이 각각 1500 nm, 500 nm인 대면적 PET 필름 위에 도입된 복합 코팅층의 두께는 60 nm 이하를 보였고 모든 영역에서 균일한 두께를 유지하고 있음을 확인하였다. 나노코팅 필름의 파장대(240~1600 nm)에 따른 투과율은 파장이 증가함에 따라 투과율 역시 점차 증가하고 있으며, 적외선 영역인 1,000 nm에서 약 48 %, 가시광선 영역에 해당하는 550 nm에서는 약 35.5 %의 투과율을 보였다. 이는 코팅된 Backcover의 요구 수준(< 40 %)에 부합한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.329-332
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• 2006

$Conform^{TM}$, a continuous extrusion forming process can produce a variety of very long extruded products such as aluminum alloyed wires, strips and profiles, hollow sectioned tubes, coated wires used in the current forming industry. This process has some advantages like as superiority of pre-heating free, availability of high extrusion ratio and continuous forming without stroke limit. But it is still difficult to analyze the realistic model of the process. In this study the analysis using two-dimensional model of $Conform^{TM}$ process together with several parametric investigations on the heat transfer are carried out by FEA code DEFORM $^{TM}2D$. In spite of simple model the results of analysis shows a good guidance to design the real process.

• 한국재료학회지
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• 제20권4호
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• pp.187-193
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• 2010

Chromium nitride (CrN) samples with two different layer structures (multilayer and single layer) were coated on bipolar plates of polymer electrolyte membrane fuel cells (PEMFC) using the reactive sputtering method. The effects with respect to layer structure on corrosion resistance and overall cell performance were investigated. A continuous and thin chromium nitride layer ($Cr_{0.48}\;N_{0.52}$) was formed on the surface of the SUS 316L when the nitrogen flow rate was 10 sccm. The electrochemical stability of the coated layers was examined using the potentiodynamic and potentiostatic methods in the simulated corrosive circumstances of the PEMFC under $80^{\circ}C$. Interfacial contact resistance (ICR) between the CrN coated sample and the gas diffusion layer was measured by using Wang's method. A single cell performance test was also conducted. The test results showed that CrN coated SUS316L with multilayer structure had excellent corrosion resistance compared to single layer structures and single cell performance results with $25\;cm^2$ in effective area also showed the same tendency. The difference of the electrochemical properties between the single and multilayer samples was attributed to the Cr interlayer layer, which improved the corrosion resistance. Because the coating layer was damaged by pinholes, the Cr layer prevented the penetration of corrosive media into the substrate. Therefore, the CrN with a multilayer structure is an effective coating method to increase the corrosion resistance and to decrease the ICR for metallic bipolar plates in PEMFC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.22-23
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• 2005

In order to increase the critical current of coated conductor, highly Bi-axially textured substrates are required. Texture uniformity of substrate is also important to fabricate high quality superconducting coated conductor because the amount of current flow along the coated conductor is limited by the defects such as bad textured area. Therefore, we need to evaluate the distribution of texture of Ni substrate along the length before buffer layer deposition on Ni tape. R2R(reel-to-reel) XRD system was used to measure the texture of long Ni substrate continuously. $\theta-2\theta$ scan of 10 m long Ni tape was measured and indicates that some of Ni(111) planes equally remain on Ni(002) textured substrate. The results of continuous Ni(220) $\Phi$-scan indicate that average FWHM is 9$^{\circ}$ within $\pm$1.

• Environmental Engineering Research
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• 제18권4호
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• pp.229-234
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• 2013

This study aimed to develop a new dust collecting system equipped with an activated carbon (A.C.) coated electrode. Before fabrication, pre-treatment of A.C. was performed to remove metal ions within the A.C. to enlarge its specific surface area. Then, pre-treated A.C., black carbon, polyvinyl acetate (PVAc), and methanol were mixed to make a gel compound, which was coated onto aluminum plates to fabricate electrodes. The optimal mixing ratio of A.C., black carbon, PVAc, and methanol was found to be 10 g: 2 g: 3 g: 20 mL. After fabrication, the electrodes were used in the batch-type experiment for $NH_3$ and $H_2S$ removal. The reduction rates of the gases were high at the beginning and slowly reduced with time. Dust collection experiments were conducted in continuous flow, with various voltages applied. Compared to 5 kV, dust removal efficiency was 1.5 times higher when 10 kV was applied. Increasing the number of electrodes applied also increased the collecting efficiency. The correlation coefficient between actual collecting efficiency and trend line was higher than 99%. Consequently, the novel dust collection system equipped with A.C. coated electrode appears to be a promising substitute for existing dust-control devices.

• 한국재료학회지
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• 제24권11호
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• pp.617-624
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• 2014

To elucidate the effects of a pretreatment process on the uniformity of Ag electroless plating on Cu flakes, pretreatment time was mainly considered with a mixed solution of 0.15 M ammonium hydroxide and 0.0375 M ammonium sulphate. Optical inspection of Ag-coated Cu flakes determined that the optimal pretreatment time is 120 s. Repetition of the sequence in which Ag plating was done immediately after the pretreatment of 120 s clearly enhanced the plating uniformity. Scanning electron microscopy revealed that holes were formed irregularly on some Cu flakes during the period from the asdropping of an Ag precursor solution to 5 min. The hole formation was judged to be due to continuous removal of Cu on the local surfaces by the repetitive formation and elimination of $Cu_2O$ or $Cu(OH)_2$ layers. However, the increase of the amount of Ag coating suppressed the hole creation and increasingly enhanced the antioxidant property.

• 한국대기환경학회지
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• 제16권4호
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• pp.381-388
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• 2000

Ceramic foam prepared with cordierite as a starting material by foam method was tested to evaluate the feasibility as a filter for the dust collection in hot gas. Two different types of agents Benzethonium chloride (BZTC, C27H42NO2Cl) and Sodium Lauryl Sulfate(SLS, CH3(CH2)11OSO3Na) were used as foaming agents in foaming process. Porosityof ceramic foam was about 80% and mean pore size were 100${\mu}{\textrm}{m}$ for SLS agent and 200 ${\mu}{\textrm}{m}$ for BZTC. It was observed that ceramic foam was composed of continuous macro-pore structure with opening windows interconnecting macro-pores. The surface of ceramic foam support of was coated with cordierite particles ranged from 20${\mu}{\textrm}{m}$ to 50${\mu}{\textrm}{m}$ Meso-pore size in the coating layer on ceramic foam was below 10${\mu}{\textrm}{m}$. While air permeability of the support increased with increasing macro-pore size coated ceramic filters showed a constant permeability without regard to the macro-pore size of the support. The permeabuilities of support varied in the range of 600$\times$10-13m2 to 1000$\times$10-13m2. For the case of coated ceramic filter it was about 200$\times$10-13m2. As a result of particle trapping test by using fly ash the particle removal efficiency was over the 99.9%.