• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.261-263
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• 2007

본 연구는 광전자 촉매시스템을 이용해 $TiO_{2}$ 졸이 코팅된 구형 비드의 광분해 효율에 대해 고찰한 것이다. $TiO_{2}$ 졸이 코팅된 구형 비드인 알루미늄비드, 유리비드, 실리카비드 화이트젤 ($1{\cdot}2{\cdot}3$형) 다섯 가지 비드를 사용하였고 실험은 산화환원지시 약인 메틸렌블루 수용액이 광촉매의 산화환원반웅을 통해 색상 및 홉광도 변화를 통해 환원 청도를 고찰할 목적으로 실행되었다. 소재별 실험 결과, 실험에 사용한 소재 중 실리카비드 화이트첼($1{\cdot}2{\cdot}3$형)만이 반응성을 나타냈다. 이들 $1{\cdot}2{\cdot}3$형은 $TiO_{2}$의 함량을 달리한 비드들이며 1형이 가장 적은 함량을 가지며 3형이 가장 많은 함량을 가지고 있다. 실험 결과 3형이 반응성이 가장 좋은 것을 알 수 있으며, 이 실험에서는 코팅물의 함량과 고정물의 상태가 광촉매 반응에 영향을 주는 것을 알 수 있다.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.341-347
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• 2010

The off-screen space openness of the movies converted a unilateral communication, which films have made audiences understand with, into an interactive communication. When the spectators see a movie, the off-screen space will be able to take out their positivity and induce their deep thinking. They won't accept information of the screen by manual operation but will participate in the narrative stories of the cinemas, thinking about the reality. In the paper, it shows that the motion pictures, which Jean Renoir and Michelangelo Antonioni produced, consist of the expressive forms of the off-screen space as well as a human has the ability sense, feeling, perception and memory associated with interacting between the off-screen space and audiences.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2696-2698
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• 2005

기존 형광램프의 조도 조절이 가능한 조광가변 전자식 안정기의 경우 조광 설정 스위치와 조광가변 전자식 안정기와의 상호 연계 동작을 위해 안정기와 스위치 사이에 전원선 이외에 별도의 통신선로를 포설해야 하고, 이에 따른 비용 증가와 시공상의 어려움이 있다. 이런 단점을 극복하기 위한 방법 중의 하나로 전력선 통신을 사용할 경우 기축 건물에도 보다 쉽게 시공할 수 있으며, 별도의 통신 선로 포설에 의한 비용 부담도 줄일 수 있다. 본 연구에서는 (주)젤라인에서 개발된 ARM9 코어를 내장한 전력선 통신 칩(XPLC30)을 이용하여 기존 조광가변 전자식 안정기에 전력선 통신 기능을 추가하여 조광설정 스위치와 안정기간의 통신이 전력선을 통하여 이루어질 수 있도록 하고, XPLC30의 여분의 프로세싱 능력을 활용하여 기존의 조광가변 전자식 안정기에서 사용하던 조광 제어 칩의 여러 기능을 XPLC30 칩이 대신 할 수 있도록 하는 전력선 기반의 조광 체어 칩의 구현에 대한 연구를 하고자 한다.

• Journal of the Korean Vacuum Society
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• v.8 no.4A
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• pp.425-431
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• 1999

$Pb(Zr_{0.52}, Ti_{0.48})O_3$ (PZT) thick films as an actuating material with conducting oxides, $(La_{0.5}Sr_{0.5}) CoO_3$ (LSCO), have been fabricated by sol-gel method for Optical Micro-Electro-Mechanical System (MEMS) devices, in which PZT/LSCO/SiO2 structures were used. In order to improve the adhesion to LSCO solution in order to enhance the wetting behavior of a water-based LSCO precursor solution and further to improve the adhesion between LSCO and $SiO_2$ layers. PZT films were made using 1-3 propanediol based precursor solution which has a high viscosity and a boiling point appropriate for thick film fabrication. In the precursor solution, Ti-propoxied and Zr-propoxied are partially substituted with acetylacetone to achieve the solution stability while maintaining reactivity. Crack free PZT films (0.8~1$\mu\textrm{m}$) have been successfully fabricated at crystallization temperatures above $700^{\circ}C$. Dielectric constants and dielectric losses of the PZT films were 900~1200and 2~5%, respectively. Piezoelectric constant $d_{33}$ of the PZT films constrained by a substrate were 200pm/V at 100kV/cm.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.365-368
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• 2009

A new concept of a small thruster for altitude control of a micro/nano class satellite is developed, which utilizes the pulsed laser energy. As the laser-based thruster does not require burning of any fuel, it gives promise of small satellite design criteria, namely light weight and cost effectiveness. In this paper, we develop gel-type material for generating strong plasma plume for enhancing thrust for propulsion. Moreover, we quantify the level of thrust via the momentum coupling coefficient measured by the pendulum system. We discover that the driving force is significantly improved via the gel-typed propellant for laser ablation.

• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.795-803
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• 1994

Ferroelectric BaTiO3 thin film was produced using BaTi-ethoxide sol. This sol was prepared from BaTi-ethoxide by a partial hydrolysis with ammonia as a basic catalyst and ethylene glycol as a chelating agent. BaTiO3 thin film was prepared from three continuous spin-coating layers of the sol on bare Si(100) wafer at 2500 rpm followed by pyrolysis at $700^{\circ}C$ for 30 min. After the heat treatment, the film was 0.200$\pm$0.010 ${\mu}{\textrm}{m}$ thick and its grain size was 0.059 ${\mu}{\textrm}{m}$. On the other hand, electrical properties were measured for BaTiO3 thin film separately prepared on Au-deposited silicon wafer. The dielectric constant and loss of the BaTiO3 thin film at room temperature was 150~160 and 0.04 respectively, which was measured at 10 kHz and oscillation level of 0.1 V. In the measurements of the dielectric properties at high temperatures, it was observed that the capacitance of the thin film increases steeply, while the dielectric loss reaches maximum around 1$25^{\circ}C$, which corresponds a phase transition from tetragonal to cubic BaTiO3.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.3
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• pp.241-247
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• 2006

The catalytic performances for CO preferential oxidation in hydrogen-rich fuels were investigated by varying the types of alumina supports, additives excluding platinum, and synthetic methods of impregnation and sol-gel synthesis. The reactions were conducted in the range of $25{\sim}300^{\circ}C$ over Pt, Co, and/or Na impregnated catalysts supported on commercial gamma-alumina, pseudoboehmite, or sol-gel derived xerogels. Catalytic activities were enhanced by cobalt addition due to strong Pt-Co interactions in the bimetallic phase. Additional sodium promoted not only the formation of the Pt-Co bimetallic interphase but also oxygen adsorption capability, giving rise to increase in the CO oxidation rate at lower temperatures. Moreover, chemical interaction between Pt and Co was considerably enhanced by sol-gel synthesis.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.3
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• pp.331-337
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• 2006

높은 이온전도도와 충분한 기계적 강도, 전해질 누수가 적은 새로운 형태의 고분자 전해질막(pore-gel SPE)을 연구 개발하였다. 다공성 PVDF-HFP 고분자막의 기공 내에 전해질 용액을 흡수시킨 후 막 내에서 젤화를 진행시켰다. 전해질 용액은 2:2:1의 비를 갖는 PC/EC/DMA에 1M SA(Salicylic acid)를 용해하고 여기에 고분자막을 용해시킬 수 있는 아세톤을 첨가하였다. 초음파를 이용함으로써 고분자막의 용액 흡수율을 증가시키고 또 고분자막에서 젤화를 촉진 시킬 수 있었다. 이렇게 젤화한 막의 이온전도도는 젤화 전 막보다 $1{\sim}2.2$ 배 향상되었고, 인장강도는 gel-type SPE 보다 40 배 증가하였으며, 전해질 누수실험결과 hybrid-type SPE는 13%의 누수를 보였으나 본 연구의 막(pore-gel SPE)은 6%로 감소함을 보였다.

• KSBB Journal
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• v.10 no.2
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• pp.166-169
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• 1995

Spores of Trichoderma harzianum TCC 52445 for control of Rhlzocronia stem canker on potato were immobilized in various natural matrix, and germination rate and some rheological properties of the spore-matrix complex were Investigated. Germination rate of gelatin gel-spore complex and potato starch gel-spore complex were 2.8% and 2.9%, respectively, but hardness and cohesiveness of the gelstin gel-spoke complex were better than those of potato starch-spore complex. The hardness and cohesiveness were increased when the spores were immobilized in hybrid gelatin gel made by mixing several different types of natural matrix, but decreased their germination rate. Addition of corn steep liquor (1%) as spore nutrient in gelatin gel-spore complex was helpful for increasing the germination rate.

• KSBB Journal
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• v.29 no.6
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• pp.437-442
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• 2014

In vitro biological activities of Aloe vera gel and skin extracts were evaluated. Total polyphenol contents of Aloe vera skin were measured 41.12 mg/g. DPPH radical scavenging activity of Aloe vera skin-70% EtOH extract, Aloe vera skin-water extract, Aloe vera gel-70% EtOH extract and Aloe vera gel-water extract were 55%, 38%, 11% and 10%, respectively. In addition, 70% EtOH extract and water extract were compared with respect to SOD-like antioxidant activity of Aloe vera-70% EtOH extract has higher activity than Aloe vera water extract. Tyrosinase inhibition rate of Aloe vera gel extract was higher than Aloe vera skin extract. Alcohol dehydrogenase (ADH) and Acetaldehyde dehydrogenase (ALDH) relative percentage activity of Aloe vera gel extract were 126% and 216%, respectively. It was suggested that Aloe vera gel and skin extracts could be used as a functional biomaterial for functional food and cosmetics.