• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.10
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• pp.25-30
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• 2009

We have developed recycling technology of ethylen carbonate to use in photoresist stripping and cleaning process, which will be core processing technology for high performance and low price semiconductor and LCD fabrication. Using this technology, it is possible for semiconductor wafer and LCD planer to process more rapid and chip, and productivity will be improved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.977-982
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• 2007

The realization of the photoresist(PR) removal method with vaporized water and ozone gas mixture has been studied for the LCD TFT array manufacturing. The developed PR stripper uses the water boundary layer control method based on the high concentration ozone production technology. We develop the prototype of PR stripper and experiment to find the optimal process parameter condition like as the ozone gas flow/concentration, process reaction time and thin boundary layer formation. As a results, we realize the LCD PR strip rate over the 0.4 ${\mu}m/min$ and this PR removal rate is more than 5 times higher than the conventional immersion type ozonized water process.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2525-2531
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• 2012

Al-Cu alloy has been used as a circuit material for its low resistance and ease to process for long years at CMOS technology. However, basically metal is very susceptible to corrosion and which has been a long pending trouble in various fields using metal. The defect causes the reliability concerns, so improved methods are necessary to reduce the defect. In the various corrosion parameters, PR strip process conditions after metal etch and optimal cleaning solutions are controllable and increase the process margin to prevent the metal corrosion. This study proposes that chlorine residue after metal etch as the source of metal corrosion, and charges should be removed by optimizing PR strip process condition and cleaning condition.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.113-116
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• 2008

As the integration in semiconductor display develops, semiconductor process becomes multilayer. In order to form several layer patterns, etching process which uses photoresistor (PR) must be performed in multilayer process. Repeated etching processes which take long time and PR residue cause mortal problems in semiconductor. To overcome such problems, we studied about the solution which eliminates PR effectively by using normal dry and wet etching method using plasma activated PR strip solvent in liquid condition. At first, we simulate the device which activates the plasma and make sure whether gas flow in device is uniform or not. Under activated plasma, etching effect is elevated. This improvement reduces etching time as well as display production time of semiconductor process. Generally, increasing etching process increases environmental hazards. Reducing etching process can save the etchant and protect environment as well.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.669-675
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• 2000

This study investigated the effect of Puerariae Flos (PF; flower of Puerariae plant) and Puerariae Radix (PR; root of Puerariae plant) water extracts on the activities on the activities of ethanol-metabolizing enzymes and free radical generating/scavenging enzymes of brain in ethanol-treated rats. Five groups of male Sprague-Dawley rats were orally administered ethanol (25%, v/v) 5 g/kg body weight/day, and sacrificed 5 weeks post treatment. PF and PR water extracts were supplemented in a diet based on 1.2g (I) or 2.4 g (II) raw PF or PR/kg body weight/day. Alcohol dehydrogenase activity of brain was significantly lowered in PF of PR groups, whereas aldehyde dehydrogenase activity was significantly higher in PR groups than those of control and PF groups. Cytochrome P-450 content, aminopyrine D-methylase and aniline hydroxylase activities were decreased in both PF and PR groups compared to control group. Aldehyde oxidase and xanthine oxidase activities tended to decrease by Puerariae plant extract supplemented goups and degree of decrease predominated in PRI. Superoxide dismutase and glutathione S-transferase activities were increased in PF or PR groups, whereas glutathione peroxidase and catalase activities were significantly decrased by Puerariae plant extracts supplement. These results indicated that supplementation of PF or PR lowers free radical generating enzymes activities. It was suggested that the activities of ethanol metabolizing emzymes and antioxidant enzymes in brain can be enhanced by PF or PR supplement in ethanol-treated rats.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.54-60
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• 1999

Three different types of lab-scale anaerobic bioreactors, AF and two-stage ASBF-PR and ASBF-SP, were evaluated in treating swine wastewater by operating at $1{\sim}2$ days of hydraulic retention time with increasing organic loading rate upto 6.3 $kg-COD/m^3{\cdot}d$ at $35^{\circ}C$. Seeding the anaerobic bioreactors with waste anaerobic digester sludge from a municipal wastewater treatment plant was effective and a 40-day acclimation period was required for steady-state operation. Three anaerobic bioreactors were effective in treating swine wastewater with COD removal efficiency of $66.4{\sim}84.9$% and biogas production rate of $0.333{\sim}0.796m^3/kg-COD_{removed}{\cdot}d$. Increases of organic loading rate by increasing influent COD concentration and/or decreasing hydraulic retention time caused decreases in COD removal efficiency and increases in biogas production rate. At relatively high organic loading rate employed in this study, the treatment efficiency of AF and ASBF-PR were similar but superior than that of ASBF-SP, indicating that porosity and pore size of the media packed in the bioreactors are more important factors contributing the performance of to bioreactors than specific surface area of the media. TKN in swine wastewater must be removed prior to the anaerobic processes when anaerobic process is considered as a major treatment process since influent TKN concentration of $1,540{\sim}1,870mg/L$ to the bioreactors adversely affect the activity of methanogenic bacteria, resulting in decreases of treatment efficiency and biogas production rate by 50%.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1089-1092
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• 2003

This paper has been studied on wafer cleaning and photoresist striping in semiconductor fabrication processes using ozone solved deionized water. In this work, we have developed high concentration ozone generating system and high contact ratio ozone solving system to get high efficiency DIO$_3$. Through this study, we obtained 11% ozone gas concentration, 99.5% of ozone efficiency and 51% of solubility in deionized water.

• Journal of the Korean Magnetics Society
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• v.2 no.1
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• pp.37-43
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• 1992

Minor phases in cast and hot-pressed R(R=Pr, Nd)-Fe-B magnet were investigated through thermomagnetic analysis. The relationship between minor phases and coercivities of R-Fe-B magnets was studied. ${\alpha}-Fe$ and $Nd_{2}Fe_{17}$ were precipitated in as-cast Pr-Fe-B and Nd-Fe-B alloys respectively. These phases were considered to deteriorate the magnetic properties of R-Fe-B magnets. During the heat treatment, ${\alpha}-Fe$ and $Nd_{2}Fe_{17}$ were annihilated and the magnetic properties of cast R-Fe-B magnet were improved. Hot-pressed Nd-Fe-B magnet showed better thermal stability than sintered magnet.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2968-2974
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• 2010

Nowadays, the PV systems have been focused on the grid connection between the power source and the grid. The PV inverter can be considered as the core of the whole system because of an important role in the grid-interfacing operation. An important issue in the inverter control is the load current regulation. In the literature, Proportional Integral (PI) controller, which is normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an AC system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. Compared with conventional PI controller, Proportional Resonant (PR) controller can introduce an infinite gain at the fundamental frequency of the AC source; hence it can achieve the zero steady-state error without requiring the complex transformation and the de-coupling technique. Theoretical analyses of both PI and PR controller are presented and verified by simulation and experiment. Both controller are implemented in a 32-bit fixed-point TMS320F2812 DSP processor and evaluated on a 3kW experimental prototype PV Power Conditioning System (PCS). Simulation and experimental results are shown to verify the controller performances.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.22-23
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• 2006

A process for removal of photoresist(PR) m semiconductor manufacturing using water vapor with ozone is presented. For the realization of the ozone/vapor mixture process, high concentration ozone generator and process facilities have developed. As a result of the silicon wafer PR strip test, we confirmed the high efficiency PR strip rates of 400nm/mm or more at the ozone concentration of 16wt%/$O_2$. The ozone/vapor mixture process is more effective than the ozonized water Immersion process.