• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.1
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• pp.1-7
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• 2001

The immediate purposes of this study is to establish the surface chemical principles associated with the flotation process of waste papers and to verify them by practical flotation experiments. To achieve this AKD sized hydrophobic microcrystallince cellulose (MCC) with different levels of hydrophobicity, and hydrophilic MCC dyed with black were prepared as model substances. The effects of surface characteristics on flotation efficiency were evaluated by measuing the brightness of the flotation rejects obtained after the flotation experiments carried out using MCC mixtures prepared with different ratios of hydrophobic and hydrophilic MCCs. Results showed that more than 90% of the flotation rejects consisted of hydrophobic MCC indicating the critical importance of the hydrophobicity of the materials in the flotation process. The proportions of hydrophobic materials in the reject remained constant when highly sized MCC was used as a model of hydrophobic substance.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.66-66
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• 2003

실리콘 박막 태양전지는 저가, 대면적 생산이 가능해 최근 주택용, 발전용의 차세대 태양전지로써 부각되고 있다. 그러나, 단결정, 다결정 태양전지에 비해 상대적으로 낮은 효율특성 때문에 그 특성을 향상시키고자 하는 다양한 연구가 진행되고 있다. 비정질/마이크로결정질 실리콘 박막 태양전지에서 광흡수층으로 사용되는 i층은 광흡수를 최대화하기 위해 암전류($\sigma$$_{d}$)가 낮고 광전류($\sigma$$_{ph}$ )가 높은, 즉, 광민감도($\sigma$$_{ph}$ /$\sigma$$_{d}$)가 높은 박막을 적용해야 한다. 한편, 도핑된 윈도우층의 경우에는 넓은 밴드갭을 갖도록 하여 윈도우층에서의 광흡수가 최소화되도록 박막을 형성해야 한다.

• Journal of Powder Materials
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• v.6 no.4
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• pp.320-324
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• 1999

The formation, microstructure and properties of novel ceramic composite materials manufactured by active-filler-controlled polymer pyrolysis were investigated. In the presence of active filler particles such as transition metals, bulk components of various geometry could be fabricated from siliconorganic polymer. Molybdenum- and tungsten-filled polymer suspensions were prepared and their conversion to ceramic composites by annealing in $CH_4$ atmosphere were studied. Dimensional change. porosity and phase distribution (filler network) were analyzed and correlated to the resulting hardness values. Molybdenum and tungsten as active filler were carburized completely to $Mo_2C$, $W_2C$ and WC in $CH_4$ atmosphere. Consequently, microcrystalline composites with the filler reaction products embedded in a silicon oxycarbide glass matrix were formed. Hardness was increased with increasing carburization and reached 8.6-9.5 GPa in the specimen pyrolyzed in $CH_4$ atmosphere.

• Carbon letters
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• v.20
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• pp.32-38
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• 2016

In this study, cellulose nanoplates (CNPs) were fabricated using cellulose nanocrystals obtained from commercial microcrystalline cellulose (MCC). Their pyrolysis behavior and the characteristics of the product carbonaceous materials were investigated. CNPs showed a relatively high char yield when compared with MCC due to sulfate functional groups introduced during the manufacturing process. In addition, pyrolyzed CNPs (CCNPs) showed more effective chemical activation behavior compared with MCC-induced carbonaceous materials. The activated CCNPs exhibited a microporous carbon structure with a high surface area of 1310.6 m²/g and numerous oxygen heteroatoms. The results of this study show the effects of morphology and the surface properties of cellulose-based nanomaterials on pyrolysis and the activation process.

• Journal of Information Display
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• v.9 no.2
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• pp.5-8
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• 2008

Bottom gate thin film transistors (TFTs) with microcrystalline and amorphous Si (a-Si) double active layers (DAL) were fabricated. Since the process of DAL TFTs can use that of conventional a-Si TFTs, these DAL TFT process has advantages, such as low cost, large substrate, and mass production capacity. In order to analyze the degradation characteristics in saturation region for driving TFTs of active matrix organic light emitting diode, three different dynamic stresses were applied to DAL TFTs and a-Si TFTs. The threshold voltage shift of DAL TFTs and a-Si TFTs during 10,000 second stress is 0.3V and 2V, respectively. DAL TFTs were more reliable than a-Si TFTs.

• Journal of the Korean Ceramic Society
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• v.47 no.1
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• pp.71-74
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• 2010

We have investigated protonic conduction in highly dense (>98%) polycrystalline Y-doepd $BaZrO_3$ (BYZ) ceramic with an average grain size of ~85 nm. It is observed that the protonic conductivity across the grain boundaries in this nano-crystallilne BYZ (n-BYZ) is significantly higher than the microcrystalline counterpart. Such a remarkable enhancement in grain boundary conductivity results in high overall conductivity that may allow this chemically stable protonic conductor to serve as a solid electrolyte for low-temperature solid oxide fuel cell applications.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1113-1116
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• 2003

This review article gives a comprehensive compilation of recent developments in low temperature deposited poly Si flms, also known as microcrystalline silicon. The development of various ion energy suppression techniques for plasma enhanced chemical vapour deposition and ionless depositions such as HWCVD and expanding thermal plasma, and their effect on the material and solar cell efficiencies are described. A correlation between ef.ciency and the two most important process parameters, i.e., growth rate and process temperature is carried out. Finally, the application of these poly Si cells in multijunction cell structures and the best efficiencies worldwide by various deposition techniques are discussed.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.609-612
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• 2011

Amphiphilic (porphyrin)Sn$(OH)_2$ molecular building block can directly translate into well-defined solid-state microcrystalline structures. The crystalline diamond plates are obtained from ethanol and crystalline square plates are grown from methanol solution. With a simple synthetic manipulation during the microcrystal growth, the morphologies can be controlled by adopting different molecular packing. Consequently, morphologies of microcrystals have been diversified. Furthermore, the macroscopic crystals were obtained in the presence of cetyltrimethylammonium bromide (CTAB).

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.873-876
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• 1999

Aspergillus sp. CX-l strain grown on microcrystalline cellulose resulted in the accumulation of high levels of cellulase and xylanase activities that were higher by two to four folds than those from the conventional commercial producer, Trichoderma reesei QM9414. Aspergillus sp. CX-1 demonstrated greater thermo stability and better catalytic characteristics of total cellulase activity (FPase) as compared to T. reesei and Aspergillus niger F-2039.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.237.2-237.2
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• 2014

이번 연구는 system-on-panel에 적용하기 위한 비휘발성 메모리의 전하보유시간 및 메모리 윈도우 특성 향상에 관한 연구이다. 이를 위해 SiO2/SiOX/SiOXNY의 메모리 구조를 이용하였으며, 채널층으로 결정화 온도에 따른 수소화된 미세결정 실리콘-게르마늄을 이용하였다. 채널 층으로 사용된 수소화된 미세결정 실리콘-게르마늄은 비정질 실리콘-게르마늄보다 더 낮은 bandgap과 더 적은 defect density로 인하여 더 향상된 전하보유시간 및 메모리 윈도우를 얻을 수 있었다. 결정화가 거의 이루어지지 않은 실리콘-게르마늄 비휘발성 메모리의 경우 약 4.9V의 메모리 윈도우를 얻을 수 있었다. 반면 300oC에서 약 43.4%의 결정화가 이루어진 실리콘-게르마늄의 메모리 윈도우는 약 5.9V로 약 17%의 향상이 있으며, 10년 후 74.5%의 높은 전하보유시간을 가졌다.