• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1093-1096
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• 2003

본 논문에서는, CMOS APS Image Sensor 내에 포함되어 회로의 면적을 줄인 새롭게 제안된 CMOS Bandgap Reference Bias Generator (BGR)를 온도 및 방사능에 대한 응답을 실험하였다. 제안된 BGR 회로의 설계 목표는 V/sub DD/는 2.5V이상이고, V/sub ref/는 0.75V ± 0.5mV 마진을 가지게 하는 것이다. 제안된 BGR회로는 Level Shifter를 갖는 Differential OP-amp단과 Feedback-Loop를 가지는 Cascode Current Mirror를 사용하여 저전압에서도 동작을 가능하게 하였으며, 높은 출력저항 특성을 가지도록 하였다. 제안된 BGR회로는 하이닉스 0.18㎛ ( triple well two-poly five-metal ) CMOS 공정을 이용하여 Test Chip을 제작하였다. 온도의 변화와 Co-60 노출조건 하에서 Total ionization dose (TID) effect된 BGR회로의 V/sub ref/를 측정하여, 이를 평가하였다. 온도에 대한 반응은, 25℃ 일 때의 V/sub ref/에 대해, 각각 45 ℃에서 0.128%. 70℃에서 0.768% 변화하였다. 그리고 온도가 25℃일 때 50krad와 100krad의 방사능을 조사 하였을 경우, V/sub ref/는 각각 2.466%, 그리고 4.612% 변화하였다.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.893-899
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• 2024

In a secondary cooling system of a sodium-cooled fast reactor (SFR), rapid detection of hydrogen due to sodium-water reaction (SWR) caused by water leakage from a heat exchanger tube of a steam generator (SG) is important in terms of safety and property protection of the SFR. For hydrogen detection, the hydrogen detectors using atomic transmission phenomenon of hydrogen within Ni-membrane were used in Japanese proto-type SFR "Monju". However, during the plant operation, detection signals of water leakage were observed even in the situation without SWR concerning temperature up and down in the cooling system. For this reason, the study of a new hydrogen detector has been carried out to improve stability, accuracy and reliability. In this research, the authors focus on the difference in composition of hydrogen and the difference between the background hydrogen under normal plant operation and the one generated by SWR and theoretically estimate the hydrogen behavior in liquid sodium by using ultra-accelerated quantum chemical molecular dynamics (UA-QCMD). Based on the estimation, dissolved H or NaH, rather than molecular hydrogen (H₂), is the predominant form of the background hydrogen in liquid sodium in terms of energetical stability. On the other hand, it was found that hydrogen molecules produced by the sodium-water reaction can exist stably as a form of a fine bubble concerning some confinement mechanism such as a NaH layer on their surface. At the same time, we observed experimentally that the fine H₂ bubbles exist stably in the liquid sodium, longer than previously expected. This paper describes the comparison between the theoretical estimation and experimental results based on hydrogen form in sodium in the development of the new hydrogen detector in Japan.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.270-274
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• 2015

We develop advanced oxidation processes for the treatment of spent electroless nickel plating solution. Apart form recovering nickel by leaching and enrichment, more emphasis is placed on rendering the waste water recyclable via oxidizing phosphite and hypophosphite into phosphate which can then be precipitated easily. $UV/H_2O_2$ process is employed and the conversion efficiency of COD and $PO_4-P$, and $H_2O_2$ consumption are analyzed. Furthermore, the $UV/H_2O_2/O_3$ process in conjunction with $O_3$ generator enables us to not only save the treatment time by 6 hours but also reduce $H_2O_2$ consumption by 30%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.329-334
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• 2005

The rocket grade hydrogen peroxide has been widely used as a monopropellant in propulsion systems. Conventional decomposition of hydrogen peroxide, however, requires preheating before feeding into the reactor. In the present paper, we described an experimental study of a catalytic reactor bed that employs multiple catalysts to enhance the low temperature response in the vicinity of the reactor inlet. $K_2MnO_4$ is experimentally chose as the inlet catalyst from the candidates of silver, platinum, $La_{0.8}Sr_{0.2}CoO_3(LSC),\;and\;K_2MnO_4$. We developed new synthesis and coating method using modified alumina sol-gel method to strengthen the adhesion of $K_2MnO_4$ catalyst. from the vaporizer experiment with hydrogen peroxide at room temperature, satisfactory vaporizing performance was measured.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.552-556
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• 2006

An advanced oxidation process catalyzed by iron ions in the presence of hydrogen peroxide, the so-called Fenton's reaction, has been applied to the treatment of steam generator chemical cleaning waste containing highly concentrated iron(III)- ethyl-enediaminetetraaceticacid (Fe(III)-EDTA) of 70000 mg/L. The experiments for the degradation of Fe(III)-EDTA were carried out not only with a simulated waste, but also with the real one. The effect of pH and the amount of hydrogen peroxide added to the waste on the degradation was examined, and the results were discussed in several aspects. The optimal pH to maximize the degradation efficiency was dependent on the amount of hydrogen peroxide added to the waste. i.e., when the amount of hydrogen peroxide was different, maximum degradation efficiency was obtained at different pH's. The optimal amount of hydrogen peroxide relative to that of Fe(III)-EDTA was found to be 24.7 mol ($H_{2}O_{2}$)/mol (Fe(III)-EDTA) at pH around 9.

• Journal of the Semiconductor & Display Technology
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• v.4 no.4 s.13
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• pp.19-26
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• 2005

The process optimization of ozone concentration and half life time was investigated in ultra pure water and alkaline solutions for the wet cleaning of silicon wafer surface at room temperature. In the ultra pure water,. the maximum concentration (35 ppm) of ozone was measured at oxygen flow rate of 3 liters/min and ozone generator power over 60%. The half life time of ozone increased at lower power of ozone generator. Additive gases such as $N_2$ and $CO_2$ were added to increase the concentration and half life time of ozone. Although the maximum ozone concentration was higher with the addition of $N_2$ gas, a longer half life time was observed with the addition of $CO_2$. When $NH_4OH$ of 0.05 or 0.10 vol% was added in DI water, the pH of the solution was around 10. The addition of ozone resulted in the half life time less than 1 min. In order to maintain high pH and ozone concentration, ozone was continuously supplied in 0.05 vol% ammonia solutions. 3 ppm of ozone was dissolved in ammonia solutions. The static contact angle of silicon wafer surface became hydrophilic. The particle removal was possible alkaline ozone solutions. The organic contamination can be removed by ozonated ultra pure water and then alkaline solution containing ozone can remove the particles on silicon surface at room temperature.

• Carbon letters
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• v.3 no.4
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• pp.205-209
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• 2002

In the reaction of gas-solid phases, the microwave energy plays a role as a catalyst, because it causes friction between adjacent molecules and enables an unique characteristics of interior heating of the materials. When the dipole gases are adsorbed inside of the pore of carbon materials, the gases are decomposed by the microwave energy and reacted with the carbon atoms. Using this principle, we could make the activated carbon from coconut shell within 20 minute, and this residence time for activation is about 1/16 of rotary kiln. The BET surface area of activated carbon made by microwave is about $1,100m^2/g$ similar to conventional method of rotary kiln. In this study, the power of microwave generator was 400~1000W, and the gas for activation was steam mainly.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.77-80
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• 2003

As rapid growth of energy demand in line with modern society's industrialization led to environmental pollution by fossil fuels, there are more and more interest and international research on energization of water, which is clean energy and comprising $70\%$ of earth. In offshore countries, the water is commercially used already and water has very attractive characteristics in terms of economy and efficiency compared to the existing gas welder. Brown Gas welder does not produce $CO_2$ from combustion of Hydrogen-Oxygen-Gas, which was gained by electrolysis of water, In this paper, the result from operating characteristic improvement of Gas Generator and Current-Controlled converter is to be considered into design in electrode, source/ controller, standized into level of whole system design base.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1083-1087
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• 1997

Every effort is now being exerted in industrialized and developing countries to reduce emission of greenhouse gases from electric power sector. In this paper, we provide supply-side resource mix strategies in the long-term generation expansion planning under the expected greenhouse gas regulations. Under the environmental regulations, we explore the least-cost generation expansion plan of Korea and determine the composition of future resource mixes. Our analysis is performed on the basis of the revised WASP package which can evaluate emission of carbon dioxide from each power plant. The evaluation process of carbon dioxide emissions, which can consider the efficiency and operating conditions of each generator simultaneously, has been incorporated into the probabilistic production cost simulation module of WASP.

• Macromolecular Research
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• v.17 no.9
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• pp.651-657
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• 2009

This study examined the optimum compositions of binder, photo-acid generator (PAG) and sensitizer for the cationic ring opening polymerization of 1,3-bis[2-(3-{7-oxabicyclo-[4.1.0]heptyl})]-tetramethyldisiloxane in the presence of polydimethylsiloxane with four epoxide moieties as a co-monomer. When diffractive efficiency (DE) values were compared quantitatively to analyze the effect of the binder on holographic photopolymerization, DE was affected by the viscosity of the binders and miscibility with the monomer mixture. Extremely low DE values were observed when the immiscible dimethyl silicone was used as a binder. Therefore, methylphenyl silicone, which is miscible with the monomer mixture, was used as the binder for further studies. The optimal conditions were a binder viscosity between 250 to 390 cP, and contents of the binder, PAG, and sensitizer were 75-125 wt%, > 6 wt% and 0.05 wt% to the total monomer mixture, respectively.