• 한국재료학회지
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• 제21권12호
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• pp.703-707
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• 2011

The electrochromic properties of tungsten oxide films grown by RF sputtering were investigated. Among the sputter parameters, first the $Ar:O_2$ ratios were controlled with division into only an $O_2$ environment, 1:1 and 4:1. The structure of each film prepared by these conditions was studied by X-ray diffraction, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. The sputter-deposited tungsten oxide films had an amorphous structure regardless of the $Ar:O_2$ ratios. The chemical compositions, however, were different from each other. The stoichiometric structure and low-density film was obtained at higher $O_2$ contents. Electrochemical tests were performed by cyclic voltammetry and chronoamperometry at 0.05 M $H_2SO_4$ solutions. The current density and charge ratio was estimated during the continuous potential and pulse potential cycling at -0.5 V and 1.8 V, respectively. The film grown in a higher oxygen environment had a higher current density and a reversible charge reaction during intercalation and deintercalation. The in-situ transmittance tests were performed by He-Ne laser (633 nm). At higher oxygen contents, a big transmittance difference was observed but the response speed was too slow. This was likely caused by higher film resistivity. Furthermore, the effect of sputtering pressure was also investigated. The structure and surface morphology of each film was observed by X-ray diffraction and scanning electron microscopy. A rough surface was observed at higher sputtering pressure, and this affected the higher transmittance difference and coloration efficiency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
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• pp.37-40
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• 2002

Superconductor wire fabricated by electrophoresis showed its critical current density depended on parameters such as applied voltage and deposition time. Substrate and suspension solutions. and its properties are also important parameters. When same optimal parameter and condition was used, deposition density of superconductor film affect directly its critical current density. In this study, therefore, electrophoretic deposition technique was utilized for a densification of YBCO superconducting wire, and researches on electrophoretic suspension solutions and additive were experimentally performed for an improvement of the critical current density of fabricated electrophoretically superconducting wire. The samples fabricated in the solution with the additive, 8 vol.% of 1% PEG(1000), showed the highest critical current density.

• 한국자원식물학회지
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• 제24권5호
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• pp.507-513
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• 2011

본 연구는 멀칭재료와 재식방법에 따른 shallot의 생육에 미치는 영향을 조사하였다. 멀칭비닐 종류별 시험에서 투명 PE필름 처리구에서 흑색 PE필름보다 엽수, 초장, 엽초장, 엽초경이 더 좋았고, 상품수량도 21%나 증수되었다. 그러나 구의 크기별 분포에서는 유의적인 차이가 없었다. Shallot의 재식밀도별 수량은 120 cm 5조(10 a당 20,833주)에서 1,332 kg으로 120 cm 2조(10 a당 12,500주)에서보다 1.7배가 증수되어 밀식재배가 유리하였다. 따라서 shallot의 재배는 투명 PE필름 멀칭에 휴폭 120 cm에 5조가 좋을 것으로 사료된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.370-370
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• 2007

The liquid crystal (LC) aligning capabilities treated on the Organic overcoat thin film surfaces by ion beam irradiation and rubbing method was successfully studied for the first time. The Organic overcoat layer was coated by spin-coating. In order to characterize the LC alignment, the microscope, pretilt angle, thermal stress, and atomic force microscopy (AFM) image was used. The good LC aligning capabilities treated on the Organic overcoat thin film surfaces with ion beam exposure of $45^{\circ}$ above ion beam energy density of 1200 eV can be achieved. But, the alignment of defect of NLC on the Organicovercoat surface at low energy density of 600 eV was measured. The pretilt angle of NLC on the Organic overcoat thin film surface with ion beam exposure of $45^{\circ}$ for 1 min at energy density of 1800eV was measured about 1.13 degree. But, low pretilt angles of NLC on the Organic overcoat thin film surface with ion beam exposure at energy density of 600, 1200, 2400, and 3000 eV was measured. Also, the pretilt angle of NLC on the rubbed Organic overcoat thin film surfaces was measured about 0.04 degrees. Finally, the good thermal stability of LC alignment on the Organic overcoat thin film surface with ion beam exposure of $45^{\circ}$ for 1 min can be measured.

• 치과방사선
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• 제22권1호
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• pp.87-94
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• 1992

The purpose of this study was to evaluate the effect of scatter radiation to dental x-ray film with long time-exposure in the different structures of the tooth, by using pinhole camera. For this study, pinhole camera, skull with tooth, and pocket dosimeter were used. The radiation with 70 and 90kVp and exposure time (minimum: 2.5 min., maximum 10 hrs.) was projected to the film in the pinhole camera. And density of the obtained x-ray film was measured with densitometer. In the intra-oral film taking, the amount of exposure of the scatter radiation affecting the thyroid gland area was measured with the dosimeter at the thyroid gland. The density of radiographs was compared in radiation projected with or without the metal cone of dental machine. The effect of the back scatter radiation to the film was also evaluated when the lead foil was removed. The obtained results were as follows: 1. A pinhole camera was a valuable device for locating the source of x-ray. 2. The scatter radiation affected the dental x-ray film when the radiation source was exposed. more than 5 hours'. In that case, the density of the scatter radiation could be observed visually. 3. The scatter radiation caused by short exposure of dental radiation didn't affect the diagnostic quality of the dental x-ray film. 4. The differences of densities between the tooth and the soft tissue according to exposure time showed 0.16 in 5 hours' exposure & 0.17 in 10 hours' exposure at 70 kVp & 0.12 in 5 hours' exposure & 0.13 in 10 hours' exposure at the 90kVp. 5. The differences of densities between the tooth and the soft tissue according to kVp showed no difference between 5 hours' exposure of tooth at 70 kVp and soft tissue at 90 kVp, but showed 0.05 high density in tooth when 10 hours' exposure at 90 kVp. 6. No difference of density was on radiographs taken with or without dental machine cone. 7. Back scatter radiation was recorded image of radiographs for only 3 min. 8. The amounts of the scatter radiation exposed to the thyroid gland in intraoral film taking were 1.12 mr in upper anterior, 0.55 mr in upper posterior, 2.75 mr in lower anterior, and 1.92 mr in lower posterior teeth.

• Progress in Superconductivity
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• 제6권1호
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• pp.13-18
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• 2004

High-.ate in-situ$ YBa_2$Cu$Cu_3$$O_{7-x}$ (YBCO) film growth was demonstrated by means of the electron beam co-evaporation. Even though our oxygen pressure is low, ∼$5 ${\times}$10^{-5}$ Torr, we can synthesize as-grown superconducting YBCO films at a deposition rate of around 10 nm/s. Relatively high temperatures of around 90$0^{\circ}C$ was necessary in this process so far, and it suggests that this temperature at a given oxygen activity allows a Ba-Cu-O liquid formation along with an YBCO epitaxy. Local critical current density shows a clear correlation with local resistivity. Homogeneous transport properties with a large critical current density ($4 ∼ 5 MA/\textrm{cm}^2$ at 77K, 0T) are observed in top faulted region while it is found that the bottom part carries little supercurrent with a large local resistivity. Therefore, it is possible that thickness dependence of critical current density is closely related with a topological variation of good superconducting paths and/or grains in the film bodies. The information derived from it may be useful in the characterization and optimization of superconducting films for electrical power and other applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.271-271
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• 2010

$BaTiO_3$(BT) has high permittivity so that has been applied to dielectric and insulator materials in 3D system-level package integration. In order to achieve excellent performance of device, the BT layer should be highly dense. In this study, BT thick films were prepared by the inkjet printing method. And these films were cured at $280^{\circ}C$ after infiltration of polymer resin. As a result, we have successfully fabricated not only the inkjet-printed hybrid BT film but also metal-insulator-metal(MIM) capacitor without sintering process. Changes in the dielectric constant of BT hybrid film with particle size and packing density were investigated. The dielectric constant was increased with increasing packing density and particle size. Further, the BT hybrid film using two different size particles had even higher packing density and dielectric constant.

• 전기화학회지
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• 제12권3호
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• pp.258-262
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• 2009

The composition and semiconducting properties of the passive films formed on Ni- (15, 30)Cr-5Mo alloys in pH 8.5 buffer solution were examined. The depth concentration profile of passive films formed on Ni-(15, 30)Cr-5Mo in pH 8.5 buffer solution showed that Mo enhances the enrichment of Cr. The Mott-Schottky plot for the passive film on Ni-(15, 30)Cr- 5Mo closely resembled that for the film on Cr, whereas those for the less Cr-enriched film on Mo-free alloys showed similar behavior to that for the film on Ni. The acceptor density was reduced by increasing Cr content in Ni-(15, 30)Cr-(0, 5)Mo alloys, but addition of Mo considerably increased the acceptor density.

• 한국전기전자재료학회논문지
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• 제22권4호
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• pp.297-302
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• 2009

We have successfully fabricated the alumina thick films using inkjet printing processes without a high temperature sintering process. Alumina suspension as dielectric ink was formulated by combining nano-sized alumina powders with an anionic polymer dispersant in formamide/water as co-solvent. The thickness of the printed alumina thick film was measured at around 5 um by field emission scanning electron microscope. The calculated packing density of 68.5 % from the printed alumina thick film was much higher than the same films fabricated by conventional casting or dip coating processes. Q factor of the dielectrics thick film infiltrated with cyanate ester resin was evaluated by impedance analyzer.

• Nuclear Engineering and Technology
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• 제32권6호
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• pp.595-604
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• 2000

Flow-Accelerated Corrosion Behavior of SA106 Gr.C steel in room temperature alkaline solution simulating the CANDU primary water condition was studied using Rotating Cylinder Electrode. Systems of RCE were set up and electrochemical parameters were applied at various rotating speeds. Corrosion current density decreased up to pH 10.4 then it increased rapidly at higher pH. This is due to the increasing tendency of cathodic and anodic exchange half-cell current. Corrosion potential shifted slightly upward with rotating velocity. Passive film was formed from pH 9.8 by the mechanism of step oxidation and the subsequent precipitation of ferrous species into hydroxyl compound. Above pH 10.4, the film formation process was active and the film became stable. Corrosion current density showed increment in pH 6.98 with the rotating velocity, while it soon saturated from 1000 rpm above pH 9.8. This seems that activation process which represents formation of passive film on the bare metal surface controls the entire corrosion process