• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.96-98
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• 2009

This report summarizes our recent efforts to produce large-grained CIGS materials from porous nanoparticle thin films. In our approach, a $Cu_xSe$ nanoparticle colloid were first prepared by reacting a mixture of CuI in pyridine with $Na_2Se$ in methanol at reduced temperature. purified colloid was sprayed onto heated molybdenum-coated sodalime glass substrates to form thin film. After thermal processing of the thin film under a selenium ambient. $Cu_xSe$ colloid and thin film were characterized by scanning electron microscopy, x-ray diffraction. The optical(direct) band gap energy of $Cu_xSe$ thin films is 1.5 eV.

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.133-140
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• 1998

The food wastes from a refectory and an eating house were heated in domestic microwave oven(700W) equipped with a fan and the drying rates and destruction of microorganisms were investigated. The drying rate was decreased with the size of food waste and the food wastes in polypropylene basket were dried faster than that on glass dish. The rate was increased with lower initial moisture content. Death rate of microorganisms was also decreased with the size of food waste. Ninety eight percent of reduction in viable cell numbers for the 400g of food waste could be achieved in 240sec of microwave irradiation. The growth of microorganisms in food wastes after microwave irradiated was observed at $32^{\circ}C$ and 95% relative humidity after 7days and the cell numbers in microwave irradiated food wastes were found to be 1/2 ~ 1/20 of the numbers in untreated wastes in accordance with the mass and the length of exposed time to microwave. To minimize the moisture and microorganisms in food wastes, the use of microwave oven are recommended.

• Journal of Information Display
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• v.9 no.1
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• pp.14-19
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• 2008

We demonstrated the capillary force lithography (CFL) method for controlling the azimuthal anchoring energy of a liquid crystal (LC) alignment layer. When a thermoplastic polymer film is heated to over the glass transition temperature, the melted polymer is filled into the mold structure by the capillary action and the aspect ratio of the pattern is determined by the dewetting time of the CFL process. Here, the proposed method showed that the azimuthal anchoring energy of the LC alignment layer could be simply controlled by the surface relief patterns which were determined by the dewetting times during the CFL patterning.

• Structural Engineering and Mechanics
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• v.53 no.6
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• pp.1253-1269
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• 2015

The present paper investigates the post heating behavior of concrete beams reinforced with fiber reinforced polymer (FRP) bars, namely carbon fiber reinforced polymer (CFRP) bars and glass fiber reinforced polymer (GFRP) bars. Thirty rectangular concrete beams were prepared and cured for 28 days. Then, beams were either subjected (in duplicates) to elevated temperatures in the range (100 to $500^{\circ}C$) or left at room temperature before tested under four point loading for flexural response. Experimental results showed that beams, reinforced with CFRP and GFRP bars and subjected to temperatures below $300^{\circ}C$, showed better mechanical performance than that of corresponding ones with conventional reinforcing steel bars. The results also revealed that ultimate load capacity and stiffness pertaining to beams with FRP reinforcement decreased, yet their ultimate deflection and toughness increased with higher temperatures. All beams reinforced with FRP materials, except those post-heated to $500^{\circ}C$, failed by concrete crushing followed by tension failure of FRP bars.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.574-579
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• 1995

Saturated boiling heat transfer experiment in a hemispherical narrow space is conducted using Freon-113 to investigate an additional heat removal capability through a hypothetical gap between lower head and degraded core. The narrow space of 1mm consists of a 124mm diameter heated stainless steel hemisphere and a glass outer vessel. Within the hemispherical narrow space large coalesced bubbles are produced and these bubbles rise in random direction, causing liquid flow in from the opposite side to fill the region. Such flow in random direction makes the flow field in the narrow space very chaotic and thus enhance heat transfer. The heat transfer coefficient is higher at lower angle and at higher heat flux. The present study shows that the liquid from upper region can effectively penetrate into the gap and augment the heat removal capability through tile gap.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.481-485
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• 1987

The fabrication of a micro mass flow sensor on a silicon chip by means of micro-machining technology is described on this paper. The operation of micro mass flow sensor is based on the heat transfer from a heated chip to a fluid. The temperature differences on the chip is a measure for the flow velocity in a plane parallel with the chip surface. An anisotropic etching technigue was used for the formation of the V-type groove in this fabrication. The micro mass flow sensor is made up of two main parts ; A thin glass plate embodying the connecting parts and mass flow sensor parts in silicon chip. This sensor have a very small size and a neglible dead space. Micro mass flow sensor can fabricate on silicon chip by micro machining technology too.

• Elastomers and Composites
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• v.57 no.3
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• pp.114-120
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• 2022

The tensile properties of the extruded PC film were measured in the extrusion direction and perpendicular to the extrusion direction. The measured properties were the elastic modulus and Poisson's ratio at the glass transition temperature of PC. The measured orthotropic properties of the film were used for the computer simulation of vacuum forming. In this simulation, three mold shapes were tested: dome, trapezoid, and cubic, and the vacuum was applied between the mold surface and the heated film. The stress, strain, thickness, and stretch ratio distributions of the film in different mold shapes were observed and compared. The thermoforming simulation method used in this study and the obtained results, considering the determined orthotropic properties, can be applied to the thermoforming of various three-dimensional shapes.

• Food Science of Animal Resources
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• v.22 no.1
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• pp.50-54
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• 2002

The aim of this work to determine the formation of lactulose during heat treatment process as a contribution to the estabilishment of limits of chemical indicators for different types of heat processed milk and analyze of lactulose for the reconstituted milk added samples. The HTST(75$\^{C}$/15s) and UHT(130$\^{C}$/2∼3s) treatment realized with a pilot plant and heat-treated samples were stroed at 4, 10, 30$\^{C}$ for 4 weeks. Changes in lactulose was evaluated at 7 days intervals. The other heat treatment was sealed in glass tube and heated at 75$\^{C}$ for 10 to 120s and heated at 130$\^{C}$ for 2 to 60s in a thermostatically controlled constant temperature bath of glycerol. The reconstituted milk was made with full fat dry milk that reconstituted with deionized water to 10% total solid, and was added to milk at 10, 20, 30% respectively. The samples processed with a HTST pilot plant showed that lactulose was contained at 1.47∼1.52mg/10()ml and 8.19 ∼8.32mg/100ml for UHT-treated samples. Changes in the lactulose content of heat-treated samples during storage at 4 and 10$\^{C}$ for 4 weeks caused a slight increase, however a noticeable increase was observed at 30$\^{C}$ for 4 week. The glass tube samples showed that high correlations between relative increase in content of lactulose and increasing processing times(75$\^{C}$ : r = 0.986, 130$\^{C}$ : r = 0.987, respectively). Added with reconstituted milk would cause a increase of the lactulose content linear with increasing addition amount(r = 0.982). This results observed for lactulose in commercial milk samples would applied to the detection of chemical changes during heat treatment and illegal use of reconstituted milk.

• Journal of the Mineralogical Society of Korea
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• v.20 no.1 s.51
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• pp.1-6
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• 2007

Hectorite was synthesized by a two-step hydrothermal process from $Mg(OH)_{2}$, water glass (${\sim}30\;wt%\;SiO_{2}$) and Li-compound at $90{\pm}5^{\circ}C$. The product shows excellent dispersion and swelling properties. The mixture of the starting materials was heated in a glass vessel for the first reaction with continuous stirring and the pH of the solution was adjusted to $6{\sim}8$, resulting in the formation of a precursor of hectorite. The excess salt components were washed out from the resulting slurry and then was matured in the glass vessel for the 2nd reaction. Li compound was added during the reaction. After a 10 h retention, the gel of hectorite was formed. The XRD pattern of the synthesized one was coincided with that of natural hectorite and SEM study revealed uniform grains 50 m in diameter. The d001 basal spacing of the product moved from 12 to $17.4\;{\AA}$ after glycolation treatment. The measured value of CEC and the swelling capacity was 90 cmol/kg and $60{\sim}70\;mL/2\;g$, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.186-193
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• 2009

In this paper, we adopted E-MOLD patent technology in order to fabricate Prismless LGP(Light Guide Panel) fur cellular phone and estimate the transcription of injection-molded parts. Then, we manufactured the Ni stamper fur Prismless LGP using MEMS process. And the stamper was installed in the movable heated core which is the key part of a patented mold. Using this mold, we manufactured injection-molded plastic LGP parts with different mold temperatures so that we investigate effect of the temperature on the transcription of the parts. The CAE analysis was also conducted in order to compare with the experimental results. The transcription of LGP parts with various mold temperature displayed $100^{\circ}C$(25.0nm), $140^{\circ}C$(48.4nm), $180^{\circ}C$(52.1nm) and when compared with stamper(521Inm), transcription was superior at $180^{\circ}C$. According to the CAE results, moldability was improved as mold temperature ($50^{\circ}C{\sim}180^{\circ}C$) increased, but when filling time($1{\sim}2sec$) increases, it decreased at $160^{\circ}C$. And transcription and moldability were improved markedly at glass transition temperature($140^{\circ}C$).