• Proceedings of the KWS Conference
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• 2002.05a
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• pp.81-82
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• 2002

• Journal of Welding and Joining
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• v.20 no.5
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• pp.55-62
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• 2002

• Journal of the Korean Ceramic Society
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• v.41 no.2
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• pp.136-142
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• 2004

A homogeneous and stable ZnO sol was prepared by dissolving the zinc acetate dihydrate(Zn(CH$_3$COO)$_2$$.$2H$_2$O) in solution of isopropanol((CH$_3$)$_2$$.$CHOH) and monoethanolamine(MEA:H$_2$NCH$_2$CH$_2$OH). ZnO thin films were prepared by sol-gel spin-coating method and investigated for c-axis preferred orientation and physical properties with preheating temperature. The c-axis growth had a difference as increaing preheating temperature. ZnO thin film preheated at 275$^{\circ}C$ and post-heated at 650$^{\circ}C$ was highly oriented along the (002) plane. After preheating at 200∼300$^{\circ}C$ and post-heating at 650$^{\circ}C$, the transmittance of ZnO thin films by UV-vis. measurement was over 85% in visible range and exhibited absorption edges at about 370 nm. The optical band gap energy was obtained about 3.22 eV, The photoluminescence emission characteristics of ZnO thin film preheated at 275$^{\circ}C$ and post-heated at 650$^{\circ}C$ was found to orange emission(620 nm, 2.0 eV) by PL measurement, which revealed the possibility for application of inorganic photoluminescence device.

• Resources Recycling
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• v.6 no.4
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• pp.24-30
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• 1997

The recent trend of recycle of mold scrap is to make high quality secondary ingot which can be used as raw malerial undcr intensive control of scrap. In this study, recycle of aluminum chlp generated atter machinmg process of castings was performed by vortex melting melhod Vortex melting technique was adopted for chip mclting process. The condition far optimal vortcx depth was decided using water mndellng experiment varying the shape, location, rotating speed of stlircr and watcr levcl. Before melting, chips were preheated at room temperame, 200, 300, $ 400^{\circ}C$and then submerged in the mirldle of vortex. The lecovery rale depending on the temperature was examined. As a result vortex depth was influenccd only by shape and rotating speed of stirrer, and the hlghest recovery rate oI 97% was obta~nedw hcn the submerged chip was preheated at $300^{\circ}C.$

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.15-25
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• 2022

In this study, the efficiency of treatment of moisture and organic matter in food waste was analyzed according to the air blast volume and preheating using the bio-drying method. Te mount of air blast volume and preheating were determined by the evaluation of temperature and CO2 during food waste treatment using the bio-drying method. As a results, the increase in the air blast volume increased the moisture removal efficiency and removal rate, but, lowered the temperature inside the bio-drying by the decease in microbial activity. In order to maintain the activity of microorganisms, it was estimated that it was necessary to inject an appropriate air blast rate according th the properties of the food waste. In this study, the injection of air blast volume at 15L/min was optimal. It was evaluated that the organic matter and water removal rates according to the presence or absence of air preheating, the organic matter removal rate and water removal rate increased by 3-5% when air preheating was not performed. Also, there was no internal aggregation caused by the generation of condensate inside the bio-drying. Therefore, for effective bio-drying of food waste, it is necessary to maintain an appropriate air blast volume to maintain microbial activity, and it is considered that injection through preheating of air is required.

• Food Engineering Progress
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• v.14 no.3
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• pp.193-201
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• 2010

The aim of this study was to analyse the quality of Yukwa puffed by using a vacuum puffing machine and compare to deep-fried Yukwa. The effect of vacuum puffing condition including heating temperature(100-${160^{\circ}C}$), preheating time(0-8 min) and vacuum puffing time(5-20 min) on physical and microstructure characteristics of the Yukwa was investigated. Vacuum puffed Yukwa at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 10 min puffing time had highest value in volumetric expansion ratio(10.04) and lowest value in bulk density(0.15 g/$cm^{3}$). The breaking strength showed the lowest value of 140 g/$cm^{3}$ in vacuum puffing Yukwa at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 15 min puffing time. The Yukwa puffed with the vacuum puffing machine at ${100^{\circ}C}$ heating temperature, 6 min preheating time and 15 min puffing time had the higher value of bulk density and the lower value of volumetric expansion ratio than those of deep-fried Yukwa. Increasing preheating time and vacuum puffing time caused an increase in white and an decrease in yellowness. The vacuum-puffed Yukwa exhibited smaller and uniform cell structure, while deep-fried Yukwa exhibited apparently in larger pores inside and smaller pores near the surface layer. The optimum condition of vacuum puffing machine for the production of vacuum-puffing Yukwa was ${120^{\circ}C}$ heating temperature, 4 min preheating time and 5 min puffing time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.267-267
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• 2006

전력에 큰 손실을 초래하는 고장전류를 차단하기 위한 한류기(FCL) 소재로서 고온 초전도체인 BSCCO 2212가 사용된다. 고온에서 용융된 BSCCO 2212 분말은 원심성형법에 의해 한류기용 튜브로 제조되었다. BSCCO 튜브의 기계적 특성을 높이고 용융온도를 낮추기 위해 $SrSO_4$(10wt-%)를 첨가하였다. 용탕은 $1200^{\circ}C$에서 완전히 용융되어 금속 몰드로 주입되었고 원심성형에 사용되는 금속 몰드는 $550^{\circ}C$ 온도로 2시간 예열 후 1020 ~ 2520 RPM으로 회전시켰다. 원심력에 의해 성형된 BSCCO 튜브는 약 48시간 동안 로에서 서냉 후 금속 몰드로부터 분리하였다. 튜브의 용이한 분리를 위해 이형제로서 BSCCO 2212 powder를 사용하였고 임계전류측정을 고려하여 Ag tape 단자를 튜브 끝단에 부착하였다. BSCCO 제조 공정에 있어서 몰드의 예열온도, 용융온도, 몰드 회전속도 등의 변수를 조절하여 최적의 조건을 확립하였다. 제조한 BSCCO 튜브의 임계전류($I_c$)와 임계전류밀도($J_c$)는 77K에서 536A와 $205A/cm^2$ 이었다. 본 연구에서는 BSCCO 2212 튜브를 제조하는 공정조건 변화와 각 조건에서 제조된 BSCCO 2212 튜브의 전기적 특성 및 그에 따른 분석에 대해 기술하였다.

• Journal of Welding and Joining
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• v.15 no.3
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• pp.56-64
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• 1997

Macrostructural characteristic of the transverse cracks and fatigue behavior were studied for EH 32 TMCP 50mm thick plate welded with FACW under the variation in preheat and interpass temperatures. Transverse cracks were detected in specimen welded with preheat and interpass temperature below $30^{\circ}C$, but cracks were not detected in the specimens welded with preheat and interpass temperatures at the range of $100~120^{\circ}C$.C. The location of crack formation was found to strongly depend upon the thickness of weld layers as regard to the plate thickness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.143-146
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• 2003

열증착법을 이용하여 copper(II) phthalocyane (CuPc)의 박막을 제작하였다. 기판의 예열 온도를 달리하여 제작된 CuPc의 박막을 x-ray diffraction, SEM, UV visible absorption spectra의 변화를 통해 관찰한 결과 결정의 구조에 따라 ${\alpha}$-phase와 ${\beta}$-phase로 구분할 수 있었다. 이러한 결정 구조의 변화는 CuPc 박막의 전기전도 특성에 영향을 달리하여 유기발광 소자에 응용이 가능할 것으로 예상된다.

• Resources Recycling
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• v.4 no.4
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• pp.37-58
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• 1995

Whole tues were put uto cement kiln inlet where the tempmalures or gas and cemcnt-raw-materials were 1050 and 800- 850.C. respcclrvely. Tl~ck iln consisls of \ulcorner-stage suspension preheatel- and air quenching coolers The amount of wusle tlrcs added in lhc normal encrgy in lhc ce~ncnlk iln was 3, 5, 7% by volume Welght and steel contents of tiles. ulti~~iaalcn d elemental analysis, ash contents. ash hsion temperature. etc, wete detcnutned to inveshgate thc prnpcrlics a1 tires and ilreir ashes. Flucluat~ons of cement kiln placess, cement quality and an pollulton were invesligalerl during lhc burning tins. When the Ieeding ralio ol wasle lires to normal cncrgy was 50'0, there was nn wlde d~ffereilces m the cemmt quctlity and air pollutcon between operation with tiles and withoul tires. Tl~ch cal iccovcry was uhout 50% w~th5 % add~tionI n the nonndl energy. There was a little lxt fluctuation of cement quultty ncld an pollution at olher feeding ralios.