• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.468-474
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• 2003

Activated carbon fibers were prepared from stabilized PAN fibers by physical and chemical activation to compare their characteristics. In this study, stabilized PAN fibers were activated by physical activation with steam and CO$_2$, and by chemical activation with KOH. The fabricated activated carbon fibers were evaluated and compared such as specific surface area, pore size distribution, pore volume, and amount of iodine adsorption. In the steam activation, a specific surface area of 1635 m$^2$/g was obtained after heat treatment at 990$^{\circ}C$. Otherwise, in the CO$_2$ activation, produced activated carbon fibers had been a specific surface area of 671 m$^2$/g after heat treatment at 990$^{\circ}C$. In chemical activation using KOH, a specific surface area of 3179 m$^2$/g was obtained with a KOH/ stabilized PAN fiber ratio of 1.5 : 1 at 900$^{\circ}C$. Nitrogen adsorption isotherms for fabricated activated carbon fibers showed type I and transformation from type I and II in the Brunauer-Deming-Deming-Teller (B.D.D.T) classification. Increasing specific surface area Increased the amount of iodine adsorption in both activation methods. Because the ionic radius of iodine was smaller than the interior micropore size of activated carbon fibers.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.820-826
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• 1988

The freezing point$(t_f)$, latent heat of freezing$({\triangle}\;H_f)$ and kinetic constant of fleering$(k_f)$ were determined from DSC thermogram at cooling rate $-2.5^{\circ}C/min{\sim}-10.0^{\circ}C/min$. The freezing point of various starches was decreased with an increase in cooling rate, and that of whole starches were lower than defatted starches. Changes of the latent heat of freezing was not observed at above cooling rate $-2.5^{\circ}C/min$. The latent heat of freezing$({\triangle}\;H_f)$ could be deduced as a function of water content(W) as follows: ${\triangle}\;H_f=0.700W-13.048$, (Kcal/kg) $(35%{\leqq}W{\leqq}70%)\;{\triangle}\;H_f=1.569W-73.861,\;(Kcal/kg)\;(W{\geqq}70%$) In the water content range $35{\sim}90$(wt %), the activation energy of various starches in freezing process was determined $126{\sim}270$ Kcal/mol.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.131-140
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• 1993

The activation energy for high temperature creep is associated with stresses, temperatures, straians And the creep strain appears to be a function of a temperature, compensated time, namely $te^{-}$.DELTA.H/RT/, and the stress. In fact this functional relation appears to be isomorphic to material structure by x-ray analyses. Applying this functional relation, the dependance of activation energy for A17075 creep was investigated. The activation energy for creep is insensitive to stress, temperature, structure, and strain. And phenomenological model agrees with experimental creep data.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.374-374
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• 2012

반도체 소자의 크기가 100 nm 이하로 감소되면 통상적인 이온 주입 조건인 이온 에너지, 조사량 및 이온 주입 각도뿐만 아니라 Dose Rate 및 모재 온도가 Dopant Profile을 조절하는 데에 있어서 매우 중요한 인자로 작용한다. 본 연구에서는 Ribbon-beam 및 Spot-beam을 사용하여 활성화 열처리 후 Dopant Profile을 분석하였다. 이온 주입은 모든 시편에서 $BF_2$를 가속 에너지 10 keV 및 조사량 $2{\times}10^{15}/cm^2$로 고정하였다. 이온 주입 후 도펀트 활성화는 100% 질소 분위기 하에서 $850^{\circ}C$-30s 조건으로 RTA 열처리를 수행하였다. Boron 및 Fluorine의 Profile은 SIMS 분석을 통하여 구하였다. Spot-beam은 Ribbon-Beam에 비하여 Dose Rate 및 Cooling Efficiency가 높기 때문에 이온 주입 후 더욱 많은 양의 Primary-defect를 발생시키고 이에 따라 두꺼운 비정질 충을 형성한다. $BF_2$ 이온 주입 된 시편에서 B 및 F의 농도 Peak-height는 a/c 계면에 위치하는 것을 관찰하였다. 또한 B 및 F의 농도 Peak-height는 Silicon 모재의 온도가 증가할수록 증가하는 것을 관찰하였다. Silicon 모재의 온도가 증가함에 따라 Active-area의 면저항이 변화하지 않는 상태에서 Vt (Threshold Voltage)가 급격히 감소함을 관찰 하였다. 비정칠 층의 두께가 증가할수록 a/c 계면 하단에 잔존하는 Residual-defect의 양이 감소하고 이는 측면확산을 감소시키는 역할을 한다는 것이 관찰되었다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.83-90
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• 1998

The effects of dopant activation anneal on GOI (Gate Oxide Integrity) of MOS capacitor with amorphous silicon gate electrode were investigated. It was found that the amorphous silicon gate electrode was crystallized and the dopant atoms were sufficiently activated by activation anneal. The mechanical stress of gate electrode that reveals large compressive stress in amorphous state, was released with increase of anneal temperature from $700^{\circ}C$ to 90$0^{\circ}C$. The resistivity of gate electrode polycrystalline silicon film is decreased by the increase of anneal temperature. The reliability of thin gate oxide and interface properties between oxide and silicon substrate greatly depends on the activation anneal temperature. The charge trapping characteristics as well as oxide reliability are improved by the anneal of 90$0^{\circ}C$ compare to that of $700^{\circ}C$ or 80$0^{\circ}C$. Especially, the lifetimes of the thin gate oxide estimated by TDDB method is 3$\times$10$^{10}$ for the case of $700^{\circ}C$ anneal, is significantly increased to 2$\times$10$^{12}$ for the case of 90$0^{\circ}C$ anneal. Finally, the interface trap density is reduced with relaxation of mechanical stress of gate electrode.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.45-50
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• 2008

In this work, stainless steel mesh-supported activated carbons were prepared using phenolic resin and cellulose fiber. $ZnCl_2$ was used as a activation reagent in this work. $ZnCl_2$-chemical activation method has been proposed to produce highly porous activated carbons. The objectives of this work were to develop an optimal condition for manufacturing activated carbon assemblies screen from stainless steel mesh and phenolic resin. The iodine number was more increased over activation temperature of $450^{\circ}C$. Iodine number was 657 mg/g at activation temperature of $550^{\circ}C$, penolic resin concentration 20% and $ZnCl_2$ concentration 15%. Iodine number was 1359.4 mg/g when 10% cellulose added to these conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.184-184
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• 1999

반도체소자의 고집적, 미세화에 따라 MOSFET 소자에서의 고농도, 미세접합이 요구되고 있다. 이러한 고농도, 미세접합을 형성하기 위하여 기존의 저에너지 이온주입법을 대체 또는 병행할 목적으로 플라즈마 이온주입방법이 활발히 연구되고 있다. 본 연구에서는 플라즈마 이온주입방법을 이용하여 (100) 실리콘 기판에 보론을 주입후 열처리하여 형성된 p+층의 도펀트의 활성화와 이온주입으로 인한 실리콘 기판의 손상을 고찰하였다. 본 실험에서 (100)실리콘 기판에 도핑할 소스 가스로 BF3을 주입하고, D.C. pulse 플라즈마 도핑시스템을 사용하여 플라즈마 내의 보론이온을 웨이퍼 홀더에 -1~-5kV의 인가된 음전압에 의해 가속시키어 실리콘 웨이퍼에 주입하였다. 주입에너지 -1kV, -3kV, -5kV와 1$\times$1015, 3$\times$1515의 dose로 주입된 실리콘 기판을 급속가열방식(RTP)을 사용하여 $600^{\circ}C$~110$0^{\circ}C$의 온도구간에서 10초와 30초로 열처리하여 도펀트의 활성화와 미세접합을 형성한 후 SIMS, four-point probe, Hall 측정, 그리고 FT-IR을 이용하여 플라즈마 이온주입된 도펀트의 거동과 활성화율을 관찰하였고 FT-IR과 TEM의 분석을 통하여 이온주입으로 인한 실리콘 기판의 손상을 고찰하였다. SIMS, four-point probe, Hall 측정, 그리고 FT-IR의 분석으로 열처리 온도의 증가에 따라 도펀트의 활성화율이 증가하였고, 이온주입 에너지와 dose 그리고 열처리 시간의 증가에 따라서 주입된 도펀트의 활성화는 증가하였다. 그리고 주입에너지와 dose 그리고 열처리 시간의 증가에 따라서 주입된 도펀트의 활성화는 증가하였다. 그리고 주입에너지와 dose를 증가시키면 접합깊이가 증가함을 관찰하였다. 이온주입으로 인한 기판손상의 분석을 광학적 방법인 FT-IR과 미세구조를 분석할 수 있는 TEM을 이용하여 분석하였다. 이온주입으로 인한 dislocation이나 EOR(End Of Range)과 같은 extended defect가 없었고, 이온주입으로 인한 비정질층도 없는 p+층을 얻을수 있었다.

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.292-304
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• 2023

Purpose: This study was conducted to obtain experimental data for the establishment of preventive measures against fire, as large and small fire accidents occur at production and storage sites of superabsorbent polymers developed for the convenience of daily life. Method: The sample container was fixed at 0.2m in both length and width, and was shaped into a rectangular cuboid with heights of 3cm, 5cm, 7cm, and 14cm to access an infinite flat plane. The sample container was fixed in the center of a thermostatic bath that was heated to a predetermined temperature according to a preset temperature control program. If the central temperature of the sample rose more than 20℃ above the set temperature, it was determined to have 'ignited', and if it remained similar to the set temperature, it was determined to have 'unignited'. Result: The critical autoignition temperature was calculated to be 212.5℃ for a sample container with a height of 3cm, 202.5℃ for 5cm, 192.5℃ for 7cm, and 177.5℃ for 14cm. The ignition induction time to reach the highest temperature was approximately 42hours for 3cm, 91hours for 5cm, 151hours for 7cm, and 300hours for 14cm. Conclusion:① As the size of the sample container increased, the autoignition temperature decreased and the ignition induction time to reach the highest temperature increased. ② The apparent activation energy was calculated to be 39.30kcal/mol, with a correlation of 99.5%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.174-184
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• 1997

Activated carbons were prepared from palm chars by steam activation. The effect of the activation temperature and time, steam concentration and flux on the n -butane adsorption properties were investigated on the basis of surface area, pore analysis and n-butane adsorption. The amount of n -butane adsorption increased with steam concentration and steam flux at higher activation temperature to the $900^{\circ}C$, however this tendancy on the activated carbons were not observed at the temperature above $900^{\circ}C$, It was shown that surface area was 978 $\textrm{m}^2$/g, average pore size was 9.3 $\AA$ and n-butane adsorption was 5.9 g /100ml in the activated carbons, prepared at $900^{\circ}C$, 185 minutes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.947-953
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• 2012

In this study we investigated the manufacturing method for the activated carbon using the char from the pyrolysis of waste tire. The physical activation method using the steam in the fixed-bed quartz reactor was used for preparation of activated carbon. The primary experiment parameters are the activation temperature, activation time, heating rate, and the injection quantity of active agent. From the results of pore distribution of activated carbon, the micropore which was made in $850^{\circ}C$ of activation temperature, $5^{\circ}C$/min of heating rate, and 3 hours of activation time was developed in biggest quantity, and mesopore and macropore were developed in the biggest quantity too. The optimum conditions for producing the activated carbon using the pyrolysis residue were $850^{\circ}C$ of activation temperature, 3 hours of activation time, $5^{\circ}C$/min of heating rate, and 3 g $H_2O/char-g{\cdot}hr$ of active agent through this study. The produced activated carbon in these conditions showed that the potentiality of utilization as activated carbon because the BET specific surface area was $517.6m^2/g$ and total pore volume was $0.648cm^3/g$.