• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.6 s.336
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• pp.23-30
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• 2005

In this paper, OPPS(oxidized porous poly-silicon) field emitters were fabricated by using various emitter-electrode metal and these electron emission characteristics were investigated for different thermal annealing effects. The addressed OPPS field emitter with Pt/Ti emitter electrode annealed at $300^{\circ}C$-1hr showed the efficiency of $2.98\%$ at $V_{ps}$=12 V and one annealed at $350^{\circ}C$-1hr showed the highest efficiency of $3.37\%$at $V_{ps}$=16V. They are resulted from the improvement of interfacial contact characteristics of thin emitter metal to an oxidized porous poly-silicon and the decrease of electrical resistance of emitter metal. The brightness of the OPPS field emitter increases linearly in $V_{ps}$ and after oxidation process for $900^{\circ}C$-50min, the brightness of the OPPS field emitter with the as-deposited Pt/Ti emitter electrode was 3600 cd/$m^2$ at the $V_{ps}$=15 V, 6260 cd/$m^2$ at the $V_{ps}$=20 V. Thermal treatment improved the adhesion between the Ti buffer layer and the oxidized porous poly-silicon and also played an important role in the uniform distribution of electric field to the emitter electrode.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.1-7
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• 2020

As of 2018, Steel slag was generated approximately 24.23 million tons. Howeve, except blast furnace slag, steel slag is a typical by-product which does not have a clearly defined purpose in recycling. Thus, countries around the world are putting great efforts into developing a purpose for the recycling of steel slag. The vast habitat foundation of marine life has been destroyed due to recent reckless marine development and environment pollution, resulting in intensification of the decline of marine resources, and a solution to this issue is imperative. In order to propose a method to recycle large amounts of by-product slag into a material that can serve as an alternative to natural aggregate, the engineering properties and applicability for each mixing factor of environment friendly porous concrete as a material for the composition of seawater purification were in this study. Regarding the nutrient elution properties, it was clear that the nutrients continuously flowed out up to an immersion time by 8 months in natural seawater; the nitrogenous fertilizer displayed excellent elution properties in this regard.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.269-269
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• 2009

염료감응형 태양전지는 다공질 $TiO_2$ 전극막, 광감응형 염료, 전해질로 구성된 전기화학적 원리를 이용한 태양전지이다. 전해질은 전자가 빠져나간 염료에 전자를 공급하고 $PtCl_4$로부터 전자를 공급받아 산화/환원 반응을 한다. $PtCl_4$는 하부 기판에서 전자를 전해질에 제공한다. 본 연구에서는 Sealant를 이용하여 전해질의 면적이 효율에 어떤 영향을 미치는지 관찰하였다. AM 1.5 (100 $mW/cm^2$)하에서의 광 에너지로 측정한 효율은 전해질 면적이 1 $cm^2$ 일 때 가장 높은 4.46%의 효율이 나타났다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.45-45
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• 2009

This paper describes the formation of porous 3C-SiC by anodization. 3C-SiC thin films were deposited on p-type Si(100) substrates by APCVD using HMDS (Hexamethyildisilane: $Si_2(CH_3)_6$). UV-LED(380 nm) was used as a light source. The surface morphology was observed by SEM and the pore size was increased with increase of current density. Pore diameter of 70 ~ 90 nm was achieved at 7.1 $mA/cm^2$ current density and 90 sec anodization time. FT-IR was conducted for chemical bonding of thin film and porous 3C-SiC. The Si-H bonding was observed in porous 3C-SiC around wavenumber 2100 $cm^{-1}$. PL shows the band gap enegry of thin film (2.5 eV) and porous 3C-SiC (2.7 eV).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.429-429
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• 2009

Nanoporous anodic alumina membranes (NAAM) with high-density through-hole pores fabricated by hard anodization of aluminum in 0.3 M oxalic acid under the applied voltage of 40 (mild anodization), 80, 100, 120 and 140 V were investigated. The current-time responses monitored using a PC-controlled anodization cell and the corresponding pore structures attainable from field-enhanced scanning electron microscopy (FE-SEM) were analyzed in order to establish the optimum fabrication process. The nanoporous structure can be produced for all the voltage conditions, while the stabilized through-hole pore formation seems to occur at 40, 80 and 140 V. The growth rate under 140 V hard anodization was over 30 times higher than under 40 V mild anodization (1.5 um/hr).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.192-195
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• 1995

PZT powders were prepared by the molten salt synthesis method. The porous PZT was prepared from a mixture of PZT an polyvinylacohol(PVA) powders by BURPS(Burnout Plastic Sphere) technique. The piezolectirc and acoustic properties with various PVA wt% were studied, Piezoelectric coefficient d$\sub$33/ of porous PZT ceramics was almost same to that of single phase PZT ceramics, The thickness mode coupling factor k$\sub$t/ was 0.53~0.59 in comparable with the single phase PZT ceramics(k$\sub$t/=0.7)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.792-796
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• 2002

In this work, porous silicon(PS) layer is used as a sensing material to detect organic gases. To do this, PS sensors with membrane structure are fabricated. The sensors were made by applying the technologies of membrane formation by anisotropic etching of silicon, and PS layer formation by anodization in HF solution. From fabricated sensors, current-voltage (I-V) curves were measured against ethanol (called alcohol), methanol and acetone gases evaporated from 0.1 to 0.5% solution concentrations at $36^{\circ}C$. As the result, all curves showed rectifying behavior due to a diode structure between Si and PS, and the conductance of sensor devices increased largely with the organic solution concentration at high voltage of 5V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.963-968
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• 2002

In this work, porous silicon (PS) layer is investigated as a sensing material to detect organic vapors such as ethanol (called alcohol), methanol, and acetone in low concentrations. To do this, PS sensors were fabricated. They have a membrane structure and comb-type electrodes were used to detect the change of electrical resistance effectively. PS layer on Si substrates was formed by anodization in HF solution of 25%. From fabricated sensors, current-voltage (Ⅰ-Ⅴ) curves were measured for gases evaporated from 0.1 to 0.5% organic solution concentrations at 36$\^{C}$. As the result, all curves showed rectifying behavior due to a diode structure between Si and the PS layer. The conductance of most sensors increased largely at high voltage of 5V, but the built-in potential on the measured Ⅰ-Ⅴ curve was lowered inversely by the adsorption effect of the organic vapors with high dipole moment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.691-694
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• 2004

염료감응형 태양전지는 다공질 $TiO_2$ 전극막, 광감응형 염료, 전해질, 상대전극으로 구성된, 전기화학적 원리를 응용한 신형태양전지이다. 염료감응형 태양전지의 상대전극으로 주로 Pt가 사용되고 있는데 본 연구에서는 탄소나노튜브를 사용하여 상대전극으로서의 가능성을 조사하였다. 제조된 탄소나노튜브 상대전극은 cyclic voltammetry와 Impedance spectroscopy을 이용하여 전기화학적 특성을 측정하였다. 또한 탄소 나노튜브 상대 전극이 태양전지의 효율 및 그 특성에 미치는 영향을 알아보기 위하여 단위 셀 태양전지를 제조하여 단파장 하에서의 광전특성을 측정하고, 이를 바탕으로 탄소나노튜브의 상대전극으로서의 가능성을 제시하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.183-186
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• 1994

Porous piezoelectric ceramics of P7T have been newly developed to apply for transducers in an echo sounder PZT powders were prepared by the molten salt synthesis method. The porous PZT was prepared from a mixture of PZT and polyvinylalcohol(PVA) powders by BURPS(Burnout Plastic Sphere) technique. The piezoelectric and acoustic properties with various PVA wt.% have studied. The density of porous PZT ceramics was decreased linearly with increasing the PVA sphere wt.%. Piezoelectric coefficient d$\_$33/ of porous PZT ceramics was almost same to that of single phase PZT ceramics. The thickness mode coupling factor k$\_$t/ was ranged over 0.53∼0.59 comparable with the single phase PZT ceramics(k$\_$t/=0.7).