• Polymer(Korea)
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• v.29 no.2
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• pp.122-126
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• 2005

The effect of Al-MCM-41 preparation methods on the catalytic degradation of linear low density polyethylene (LLDPE) was investigated. Al-MCM-41 catalysts were synthesized by direct method (Al-MCM-41-D) and post treatment method (Al-MCM-41-P) and their characteristics were elucidated by XRD, BET, $NH_3\;TPD,\;^{27}Al$ MAS NMR. TGA kinetic analysis showed that the catalytic activation energies of Al-MCM-41-D and Al-MCM-41-P were 191.54 and 114.26 kJ/mol, respectively. The higher catalytic activity of Al-MCM-41-P would be attributed to its smaller pore size as well as higher number of acid sites that are accessible.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.215-218
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• 2007

The aim of this study is to test the feasibility of Pt/Al-MCM-41 for the dioxin decomposition reaction. For model reaction, 1,2-dichlorobenzene was decomposed instead of dioxin. $Pt/{\gamma}-Al_2O_3$ was compared with Pt/Al-MCM-41. Al-MCM-41 catlaysts were prepared by post grafting method and the Pt/Al-MCM-41 catalysts with Si/Al = 15, 30 showed higher catalytic activity than $Pt/{\gamma}-Al_2O_3$. Their higher catalytic activities were related with acid amounts. Especially Al-MCM-41 with ion exchanged with $H^+$ enhanced catalytic activity.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.674-678
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• 2023

The effect of Pt was investigated to the catalytic methane decomposition of CH₄ to H₂ over Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 using a fixed bed flow reactor under atmosphere. The Fe₂O₃ and Pt crystal phase behavior of fresh Pt(1)-Fe(30)/MCM-41 were obtained via XRD analysis. SEM, EDS analysis, and mapping were performed to show the uniformed distribution of nano particles such as Fe, Pt, Si, O on the catalyst surface. XPS results showed O^2-, O^- species and metal ions such as Pt⁰, Pt²⁺, Pt⁴⁺, Ft⁰, Fe²⁺, Fe³⁺ etc. When 1 wt% of Pt was added to Fe(30)/MCM-41, automic percentage of Fe2p increased from 13.39% to 16.14%, and Pt4f was 1.51%. The yield of hydrogen over Pt(1)-Fe(30)/MCM-41 was 3.2 times higher than Fe(30)/MCM-41. The spillover effect of H₂ from Pt to Fe increased the reduction of Fe particles and moderate interaction of Fe, Pt and MCM-41 increased the uniform dispersion of fine nanoparticles on the catalyst surface, and improved hydrogen yield.

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.291-296
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• 1999

The immobilization of APTMS(3-(2-aminoethylamino)propyltrimethoxysilane) and AAPTMS(3-(2-(2-aminoethyl)aminoethylanino)propyltrimethoxysilane) on the surface of high quality mesoporous molecular sieves MCM-41 and MCM-48 have been confirmed by F.T.-IR spectroscopy, Raman spectroscopy, 29Si solid state NMR, and a surface polarity measurement using Reichardt's dye. The formation of metal (Co(Ⅱ), Ni(Ⅱ), and Cu(Ⅱ)) complexes by immobilized aminosilanes have been investigated by photoacoustic spectroscopy(PAS). The assignment of UV-Vis. PAS bands makes it possible to identify the structure of metal complexes within mesoporous molecular sieves. Co(Ⅱ) ion may be coordinated mainly in a tetrahedral symmetry by two APTMS onto MCM-41, and in an octahedral one by two AAPTMS. Both Ni(Ⅱ) and Cu(Ⅱ) coordinated by aminosilanes within MCM-41 form possibly the octahedral complexes such as [Ni(APTMS)2(H20)2]2+, [Ni(AAPTMS)2]2+, [Cu(APTMS)2(H2O)2]2+, and [Cu(AAPTMS)(H2O)3]2+, respectively. The PAS band shapes of complexes onto MCM-48 are similar to those of corresponding MCM-41 with the variation of PAS intensity. Most of metal ion(Ⅱ) within MCM-41 and MCM-48 are coordinated by aminosilanes without the impregnation on the surface.

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.715-719
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• 1999

The incorporation of cobalt into mesoporous molecular sieves MCM-41 and MCM-48 was carried out. Co-PO/MCM41 and Co-PO/MCM48 were prepared using Co(II) acetate solution adjusted to pH = 3.0 with phosphoric acid by the incipient wetness method. Photoacoustic spectroscopy (PAS) was used to study the local environments of Co(II) incorporated into mesopores. The band around 500 nm in PAS of as-prepared Co-PO/MCM41 and Co-PO/MCM48 with Co(II) acetate solution was changed to triplet bands around 600 nm. This could be assigned to the 4 A2(F)-> 4T1(P) transition of Co(II) surrounded tetrahedrally by oxygen ions after calcination. It may be attributable to that the octahedral cobalt species containing phosphate ligands in coordination sphere reacting with framework's silanol groups to be dispersed atomically onto the surface of mesoporous molecular sieves as a tetrahedral species. This is unlike that the Co in Co-Cl/MCM41 and direct-synthesized Co-MCM41 transforms to Co oxide phase upon calcination. Co-PO/MCM41 and Co-PO/MCM48 were stable while treated with water.

• Membrane and Water Treatment
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• v.7 no.6
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• pp.495-505
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• 2016

Mesoporous MCM-41 was deposited on an inexpensive disk shaped ceramic support through hydrothermal technique for ultrafiltration of $Fe^{3+}$ from aqueous solution. The ceramic support was fabricated using uni-axial compaction technique followed by sintering at $950^{\circ}C$. The characteristics of MCM-41 powder as well as the composite membrane were examined by X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), porosity and pure water permeation test. The XRD result revealed the good crystallinity and well-resolved hexagonally arranged pore geometry of MCM-41. TGA profile of synthesized MCM-41 zeolite displayed the three different stepwise mechanisms for the removal of organic template. The formation of MCM-41 on the porous support was verified by FESEM analysis. The characterization results clearly indicated that the accumulation of MCM-41 by repeated coating on the ceramic disk directs to reduce the porosity and pore size from 47% to 23% and 1.0 to $0.173{\mu}m$, respectively. Moreover, the potential of the fabricated MCM-41 membrane was investigated by ultrafiltration of $Fe^{3+}$ from aqueous stream at various influencing parameters such as applied pressure, initial feed concentration and pH of solution. The maximum rejection 85% was obtained at applied pressure of 276 kPa and the initial feed concentration of 250 ppm at pH 2.

• Analytical Science and Technology
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• v.19 no.3
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• pp.211-217
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• 2006

Diphenyl amine (DPA) was polymerized inside the channels of the mesoporous silica (MCM-41). MCM-41 (C) and MCM-41 (D) were prepared with cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), respectively and used as hosts. Initially, the self assembly of DPA inside the pores of MCM-41 was made in ${\beta}$-naphthalene sulfonic acid (NSA) medium and subsequently poly (diphenylamine), PDPA was formed by oxidative polymerization. $N_2$ adsorption-desorption measurements of PDPA loaded MCM-41 (C) and MCM-41 (D) show variations in pore volume and surface area between them. A tubular form of poly (diphenylamine), PDPA was envisaged to form in the pores of MCM-41 and supported by high resolution transmission microscopy. The presence of PDPA inside the channel of MCM-41 was further confirmed by FTIR spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.3
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• pp.31-36
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• 2000

We developed embedded inductors in MCM-D substrate for RF applications. The increasing demand for high density packaging was the driving forces to the development of MCM-D technology. Most of these development efforts have been focused on high performance digital circuits. However, recently there is a great need fur mixed mode circuits with a combination of digital, analog and microwave devices. Mixed mode modules often have a large number of passive components that are connected to a small number of active devices. Integration of passive components into the high density MCM substrate becomes desirable to further reduce cost, size, and weight of electronic systems while improving their performance and reliability. The proposed MCM-D substrate was based on Cu/photosensitive BCB multilayer and Ti/Cu is used to form the interconnect layer. Seed metal was formed with 1000 $\AA$ Ti/3000 $\AA$ Cu by sputtering method and main metal was formed with 3 $\mu\textrm{m}$ Cu by electrical plating method. The multi-turn sprial inductors were designed in coplanar fashion. This paper describe the manufacturing process of integrated inductors in MCM-D substrate and the results of electrical performance test.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3479-3482
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• 2013

Background: Proliferation markers widely have been used to diagnose and determine the behaviour and prognosis of benign and malignant tumours. Minichromosome maintenance 3 (MCM3) is a novel proliferation marker. The aim of this study was to evaluate and compare MCM3 with Ki-67 in diagnosis of salivary gland tumours. Materials and Methods: In this retrospective study, immunohistochemical expression of MCM3 and Ki-67 was evaluated in 15 pleomorphic adenomas (PA), 17 mucoepidermoid carcinomas (MEC) and 18 adenoid cystic carcinomas (ADCC). Labeling indices (LIs) for the two markers were calculated and compared. Results: MCM3 and Ki-67 LIs were significantly higher in MEC and ADCC compared to PA. The LI of MCM3 was significantly higher than that of Ki-67 in MEC and PA. There was no significant difference between the two markers in ADCC. A cut-off point of 8% with 74.3% sensitivity and 93.3% specificity for MCM3 was obtained to discern between benign and malignant tumors. Conclusions: These results suggest that MCM3 might be a useful proliferation marker for differential diagnosis and recognition of clinical behavior of salivary gland tumors.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1020-1027
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• 1999

Heteropoly acid(HPW) catalysts supported on three different carriers, an amorphous silica, MCM-41 and MCM-48, with different loadings and calcination temperatures have been prepared and characterized by X-ray diffraction, nitrogen physorption, infrared spectroscopy, and $^{31}P$ magic angle spinning NMR. From the result of IR and NMR, it was shown that HPW retains the Keggin structure on the supported catalysts. No HPW crystal phase was developed even at HPW loadings as high as 35 wt % on the MCM-41 and 65 wt % MCM-48. Thus, HPW appeared to form finely dispersed species. In the hydrolysis reaction of di, bis, tri-pentaerythritol, HPW/MCM-41, 48 exhibited higher catalytic activity than $HPW/SiO_2$ or HPW.