• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.26-29
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• 1992

In this study, We made use of interelectrode capacitively coupled type plasma polymerization apparatus in order to make th organic optical thin films. We adopted in Benzen. Styrene, which have optical function in the organic world. It is manufactured polymerization thin films and examined optics properties by it respectively. We have known that the refractive index decreased as discharging power increased. At the middle wave length as 550[nm], the refractive index of Styrene is smaller than one of Benzen. Then, it is known that measured results are valid because the extinction coefficient(K) is about 10$\^$-4/ for variation of refractive index.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1544-1546
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• 2003

In this study, composite materials were put to dry interfacial treatment by use of plasma technology. It has been presented that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system Pressure, 100 W of discharge power, and 3 minutes of discharge time. The decrease in surface potential of charged samples by corona discharge indicates that the amount of accumulated electrical charges reduces and the charges that have been injected lessen rapidly when the duration of UV irradiation increases. The surface resistivity and the tensile strength of plasma treated samples, a longer UV irradiation time resulted in decreased insulation.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.798-806
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• 1993

In this study we developed the synthesis of high purity tungsten oxide from tungsten chlorides obtained by the chlorination of scheelite in a fluidized bed reactor. Within a minute of dissolution time, tungsten chlorides were almost dissolved in $H_2O_2$ solution. The proper dissolution conditions for the tungsten chlorides were as follows : $H_2O_2$ concentration 0.5%, dissolution temperature $15^{\circ}C$ and $H_2O_2$ amount to 0.5g tungsten chlorides 30ml. Under above conditions, the tungsten oxide prepared from dissolved product was identified as $WO_3$ and the purity of $WO_3$ was 99.53%.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.133-136
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• 2004

Since the residential load is an AC load and the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.293-294
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• 2018

Yangia sp. TSBP01, isolated from tidal flat sediment contaminated by the oil spill, is known to convert indole to indigo via an intermediate called indoxyl. Our analysis revealed that Yangia sp. TSBP01 contained the genome of 5,165,974 bp (G + C content: 66.5%) being composed of two chromosomes and five plasmids. This strain had genes encoding several oxygenases such as indole oxygenase directly involved in the conversion of indole to indoxyl.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.1
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• pp.15-21
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• 2017

In the present work, the synergistic effect of seaweed addition on organic acid production from sludge was investigated. The batch experiment was conducted at various mixing ratios of sewage sludge and seaweed (100:0, 75:25, 50:50, 25:75, 0:100 on a COD basis) under the substrate concentration of 20 g COD/L. The fermentation temperature was conducted under mesophilic condition ($35^{\circ}C$) and a heat-treated ($90^{\circ}C$ for 20 min) anaerobic digester sludge was used as a seeding source to suppress the methanogenic activity, The results showed that the amount of organic acid production increased as the content of seaweed increased: organic acids were 1.45, 3.22, 4.28, 5.24 and 4.82 g COD/L for the mixing ratio of 100:0, 75:25, 50:50, 25:75 and 0:100 respectively. The synergistic effect was calculated based on the organic acid production of individual sludge and seaweed, and was found to be 0.92, 1.14, 1.26 g COD/L at the mixing ratio of 75:25, 50:50 and 25:75, which indicates that 40% of synergy was obtained when 25% of seaweed was added. The synergistic effect could be ascribed to the high C/N ratio and biodegradability of seaweed.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.609-615
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• 1994

Partial oxidation of ethylene over 10wt% $Ag/{\alpha}-Al_2O_3$ catalyst was studied with a pulse reactor which was connected directly to a G. C. When ethylene was injected after oxygen injection at the temperature where molecular adsorption of oxygen is difficult ethylene oxide was evolved. From the results, it is suggested that adsorbed atomic oxygen is related with the evolution of ethylene oxide. The selectivity to ethylene oxide decreased with the decrease of the amounts of adsorbed oxygen and bulk oxygen. Ethylene oxide was either decomposed to ethylene and adsorbed oxygen or isomerized to acetaldehyde. However, the isomerization of ethylene oxide to acetaldehyde was strongly suppressed by the preadsorbed oxygen.

• Journal of Powder Materials
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• v.16 no.6
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• pp.389-395
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• 2009

A Si-CuO-graphite composite was prepared by a mechanical alloying (MA) method. The Si-CuO composite has a mixture structure, where CuO is homogeneously dispersed in Si. Also, $Cu_2O$ and $Cu_3Si$ phases were formed during MA and heat treatment. Graphite with the Si-CuO composite was mixed in the same mill for 30 minutes with weight ratio of Si-CuO composite and graphite as 1:1. The Si-CuO composite was homogeneously covered with graphite. SiC phase was not formed. Electrochemical tests of the composite have been investigated, and the first charge and discharge capacities of the material were about 870mAh/g and 660mAh/g, respectively. Those values are about 76% of the first cycle efficiency. The cycle life of the composite showed that the initial discharge capacity of 660 mAh/g could be maintained up to 92% after 20 cycles.

• Fashion & Textile Research Journal
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• v.5 no.4
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• pp.408-412
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• 2003

The micro structure of POY was modified and a wool-like touch yarn of composite fibers with different shrinkage was made. With this yarn 12 different fabrics with wool like touch were prepared. The characteristic physical property changes of the fabrics examined are as follows: 1. In all cases, the initial high shrinkage stages were observed in hot water treatment and the 3D images of complex multilayer of typical doubling fibers with different shrinkage were also observed in hot air treatment of 170C. 2. The tensile strength changes of satin and plain fabrics with the change of twist count showed similar behavior. However, WT's were slightly higher and RT's was lower in twill and satin fabrics than those in plain fabric. 3. Since a slight decrease of B's of twill fabric found with increasing twist count under given experimental condition, it could be influenced on the anti-drape stiffness was decreased and flexibility was increased. 4. A significant decrease of G values was observed in the twist count 800-1000 T.P.M However, in the twist count higher than 1000 T.P.M G values observed were kept nearly constant. 5. MIU of plain and twill fabrics showed a drastic decrease at the twist count higher than 1000 T.P.M.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1004-1005
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• 2006

This paper investigates a speed sensorless control of induction motor. The control strategy is based on MRAS (Model Reference Adaptive System) using load-torque observer as a reference model for flux estimation. The speed response of conventional MRAS controller characteristics is affected by variations of load torque disturbance. In the proposed system, the speed control characteristics using a load-torque observer control isn't affected by a load torque disturbance. Simulation results are presented to prove the effectiveness of the adaptive sliding mode controller for the drive variable load of induction motor.