• 한국입자에어로졸학회지
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• 제11권3호
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• pp.87-92
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• 2015

MCM-41 (Mobil Composition of Matter) and SBA-15 (Santa Barbara Amorphous) were used as a supported catalyst for ethylene polymerization due to their combination of large surface area and wide range of pore size distribution. The morphology of supports was used to control the morphology of the resulting polymer. Different molar ratios of Al/Ti were used for ethylene polymerization at $60^{\circ}C$ under atmospheric pressure. The effect of different mass ratios of MCM-41/SBA-15 and 1-hexene concentration on polymerization activity and polymer properties was investigated. The catalytic activity and the crystallinity reached the highest value at Al/Ti of 480. Upon incorporation of MCM-41 and SBA-15 into $MgCl_2/TiCl_4$ catalyst, the molecular weight and crystallinity of polyethylene were enhanced. The obtained polyethylene showed melting temperature between 130 and $135^{\circ}C$. The polyethylene with replication structure of support and bimodal MWD was expected.

• Korean Chemical Engineering Research
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• 제47권4호
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• pp.410-417
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• 2009

중간세공크기(mesopore)의 MCM41에 Imidazole을 담지시킨 CP-MS41 고체 입자의 촉매를 사용하여 GMA 용액에 $CO_2$를 흡수시켜 $CO_2$의 흡수기구로부터 GMA와 $CO_2$의 반응속도론을 고찰하였다. 대기압에서 회분식 흡수조를 사용하여 임펠러의 교반속도, 50 rpm, 촉매, 2 g, 반응온도, 60, 70, $80^{\circ}C$, GMA의 농도, $0.1{\sim}3.0kmol/m^3$, 용제, DMA, NMP, DMSO에서 측정한 $CO_2$의 흡수속도와 경막설에 의한 물질수지식을 사용하여 반응속도상수를 구하였다.

• 한국자기공명학회논문지
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• 제3권2호
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• pp.109-126
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• 1999

The location of Cu(II) exchanged into measoporous aluminosilicate MCM-41(AlMCM-41) material and its interaction with various adsorbate molecules were investigated by electron spin resonance and electron spin echo modulation spectroscopies. Cu(II) is fully coordinated to adsorbates in a wide open mesopore of AlMCM-41 for the formation of favorable complexes. It was found that in the fresh hydrated material, Cu(II) is octahedrally coordinated to six water molecules as evidenced by an isotropic room temperature ESR signal. This species is located in a cylindrical MCM-41 channel and rotates rapidly at room temperature. Evacuation at room temperature removes some of these water molecules, leaving the Cu(II) coordinated to less water molecules and anchored to oxygens in an MCM-41 channel wall. Dehydration at 450$^{\circ}C$ produces one Cu(II) species located on the internal wall of a channel, which is easily accessible to adsorbates. Adsorption of adsorbate molecules such as water, methanol, ammonia, pyridine, aniline, acetonitrile, benzene, and ethylene on a dehydrated Cu-AlMCM-41 material causes changes in the ESR spectrum of Cu(II), indicating the complex formation with these adsorbates. Cu(II) forms a complex with six molecules of methanol as evidenced by an isotropic room temperature ESR signal and ESEM analysis like upon water adsorption. Cu(II) also forms a square planar complex containing four molecules of N-containing adsorbates such as ammonia, pyridine and aniline based on resolved nitrogen superhyperfine interaction and their ESR parameters. However, Cu(II) forms a complex with six-molecules of acetonitrile based on ESR parameters. Only one molecule of benzene or ethylene is coordinated to Cu(II).

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1507-1510
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• 2011

In this study, mercury vapor adsorption behaviors for some kinds of porous materials having various pore structures were investigated. The specific surface area and pore structures were studied by BET and D-R plot methods from $N_2$/77 K adsorption isotherms. It was found that the micropore materials (activated carbons, ACs) showed the highest mercury adsorption capacity. In a comparative study of mesoporous materials (SBA-15 and MCM-41), the adsorption capacity of the SBA-15 was higher than that of MCM-41. From the pore structure analysis, it was found that SBA-15 has a higher micropore fraction compared to MCM-41. This result indicates that the mercury vapor adsorptions can be determined by two factors. The first factor is the specific surface area of the adsorbent, and the second is the micropore fraction when the specific surface areas of the adsorbent are similar.

• 분석과학
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• 제31권1호
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• pp.1-6
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• 2018

We used differential scanning calorimetry and a thermogravimetric analysis to investigate the effect of being confined in mesoporous MCM-41 on the decomposition of lithium borohydride and magnesium borohydride when heated. The confinement did not cause a phase transition of the metal borohydrides inside MCM-41, but did lower their decomposition temperature. With the exception of a lowering of the temperature, the decomposition reaction mechanism of the metal borohydrides was nearly the same for both the bulk and confined samples.

• 한국자기공명학회논문지
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• 제1권2호
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• pp.126-140
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• 1997

Mesoporous MCM-41 gallosilicate material was synthesized through shifting through shifting gallosilicate polymer equilibrium towards a MCM-41 phase by addition of acid. The location of Cu(II) exchanged into MCM-41 and its interaction with various adsorbate molecules were investigated by electron spin responance and electron spin echo modulation spectroscopies. It was found that in the fresh hydrated material, Cu(II) is octahedrally coordinated to six water molecules. This species is located in a cylindrical channel and rotates rapidly at room temperature. Evacuation at room temperature removes three of these water molecules, leaving the Cu (II) coordinated to three water molecules and anchored to oxygens in the channel wall. Dehydration at 45$0^{\circ}C$ produces one Cu (II) species located in the inner surface of a channel as evidenced by broadening of its ESR lines by oxygen. Adsorption of polar molecules such as water, methanol and ammonia on dehydrated CuNa-MCM-41 gallosilicate material causes changes in the ESR spectrum of Cu (II), indicating the complex formation with these adsorbates. Cu (II) forms a complex with six molecules of methanol as evidenced by an isotropic room temperature ESR signal and ESEM data like upon water adsorption. Cu(II) also forms a complex containing four molecules of ammonia based on resolved nitrogen superhyperfine interaction.

• 한국환경과학회지
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• 제19권6호
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• pp.681-687
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• 2010

Mesoporous silica was prepared from hydrothermal synthesis using gel mixture of tetraethylorthosilcate (TEOS) as silica source and cetyltrimethylammonium bromide (CTMABr) as a surfactant. In the optimum synthesis cause, molar ratio of template and silica changed. The surface and structure properties of mesoporous silica were determined by XRD, SEM, TEM and BET. Also, surface potential of mesoporous silica was measured using zeta potential. $N_2$ adsorption isotherm characteristics, including the specific surface area ($S_{BET}$), total pore volume $V_T$), and average pore diameter ($D_{BJH}$), were determined by BET. As a result, SBET of $100m^2/g{\sim}1500m^2/g$ was determined from the $N_2$ adsorption isotherm. Also, the average pore diameter was 2 nm∼4 nm. Mesoporous silica's surface potential of minus charge was determined from zeta potential.

• 공업화학
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• 제16권3호
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• pp.413-421
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• 2005

저온 플라즈마 반응과 광촉매 반응을 복합적으로 사용하여 휘발성 유기화합물(Volatile Organic Compounds)의 일종인 고농도(1000 ppm) 톨루엔의 분해에 대한 연구를 수행하였다. 사용된 촉매는 균일한 기공크기를 갖는 hexagonal 형태의 Mn-Ti-MCM-41 촉매로서, 수열 합성법으로 합성하였고, XRD, XPS, TEM, BET/ICP, $NH_3$/Toluene-TPD 등의 특성 분석을 통해서 톨루엔의 분해반응에 적절한 촉매임을 확인할 수 있었다. 상온($20^{\circ}C$)에서 반응을 실시하였고, 반응기에 인가된 전압은 9.0 kV로 고정하였다. 실험결과, 플라즈마 단독 시스템에서 톨루엔의 분해반응을 실시하였을 때 광촉매 단독 시스템에서 보다 40% 이상 활성이 향상되었다. 그러나 플라즈마 단독 시스템에서는 페놀, $C_2{\sim}C_4$의 알켄류 등의 부생성물의 발생량이 증가하였다. 한편, 플라즈마-광촉매 복합 시스템에서 톨루엔의 분해를 실시하였을 경우, 부생성물의 발생량이 현저하게 줄어들었다. 한편, 플라즈마-광촉매 복합 시스템에서 톨루엔의 분해를 실시하였을 경우, 부생성물의 발생량이 현저하게 줄어들었다. 특히, Mn5mol%-Ti-MCM-41 촉매를 사용하였을 경우 분해된 톨루엔의 농도 800 ppm 중에서 $CO_2$로의 전환율은 43.9%로 다른 촉매들에 비해 가장 높은 선택도를 보였다. 이는 플라즈마-광촉매 복합 시스템이 톨루엔의 분해 반응에 있어서 광촉매 반응이나 플라즈마 단독 반응에 비해 효과적임을 알 수 있었다.

• 마이크로전자및패키징학회지
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• 제5권2호
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• pp.49-52
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• 1998

이동통신용 핵심 부품인 W-LAN용 RF-Switch를 설계 및 제작하였다. 본 연구에서 는 CAD를 이용한 전송선로 설계기술, 소형화, 다층화 설계기술, 이동통신용 MCM 부품의 패턴설계를 개발하였으며 RF-Switch 설계하는기법 소형화 및 다층화를 위한 MCM공법을 얻을수 있었다. Ant-Rx On시 삽입손실은 0.48dB로 나타났다.

• Carbon letters
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• 제18권
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• pp.62-66
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• 2016