• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.77-85
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• 1991

A series of samples having different $SiO_2/Al_2O_3$ ratio were prepared by treating hydrogen mordenites with boiling hydrochloric acid and with hydrofluoric acid. The acidities of these samples were measured by TPD of $NH_3$ and by pyridine adsorption using IR, and the catalytic activities and selectivities of isomerization were measured for the reaction of ortho-xylene. For the samples treated by boiling hydrochloric acid, the acidities decreased with the increasing $SiO_2/Al_2O_3$ ratio caused by the extraction of framework aluminum. The sample having the $SiO_2/Al_2O_3$ ratio or 22 showed better activity than the others. For the samples treated by hydrofluoric acid, the content of chemically binding fluorine increased with the increasing contact time of hydrofluoric acid solution. The catalytic activities decreased with the hydrofluoric acid treatment due to the decreased acid sites resulted from the extraction of aluminum and silicon as well as the hydroxyl group replacement by the fluoride ion. The slightly increasing catalytic activities, however, came from the newly created acid sites, due to the removal of surface silicon, having enhanced by the inductive effect of binding fluorin with further acid treatment.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.49-55
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• 2016

The effects of post-annealing and temperature/humidity conditions on the interfacial adhesion energies of atomic layer deposited RuAlO diffusion barrier layer for Cu interconnects were systematically investigated. The initial interfacial adhesion energy measured by four-point bending test was $7.60J/m^2$. The interfacial adhesion energy decreased to $5.65J/m^2$ after 500 hrs at $85^{\circ}C$/85% T/H condition, while it increased to $24.05J/m^2$ after annealing at $200^{\circ}C$ for 500 hrs. The X-ray photoemission spectroscopy (XPS) analysis showed that delaminated interface was RuAlO/$SiO_2$ for as-bonded and T/H conditions, while it was Cu/RuAlO for post-annealing condition. XPS O1s peak separation results revealed that the effective generation of strong Al-O-Si bonds between $AlO_x$ and $SiO_2$ interface at optimum post-annealing conditions is responsible for enhanced interfacial adhesion energies between RuAlO/$SiO_2$ interface, which would lead to good electrical and mechanical reliabilities of atomic layer deposited RuAlO diffusion barrier for advanced Cu interconnects.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.389-390
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• 2010

this study is preliminary experimental research for develop methods to utilize the natural Hwangtoh as replacement materials for the cement in concrete, via alkali activation at $60^{\circ}C$ using NaOH solution and liquefied $Na_2SiO_3$ in a manufacture process of Hwangtoh concrete binder.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.101-104
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• 2006

유기물 박막에서 누설전류의 크기는 트랜지스터의 성능과 관련된 중요한 요소이다. 일반적으로 사용되고 있는 반도체 소자에서의 절연 막으로서 $SiO_2$ 표면을 유기물로 처리하여 $SiO_2$ 박막 표면의 화학적 반응에 대하여 FTIR 분석법을 이용하여 조사하였다. $1100cm^{-1}$에서 $1570cm^{-1}$까지의 주픽에 대하여 분석한 결과, OTS처리함량에 따라서 샘플의 $Si-CH_3$ 픽의 함량이 증가하는 것을 알 수 있었으며, 0.7%의 샘플에서 급격한 변화가 일어나고 있다는 것을 확인하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.169-178
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• 1998

The crystal phases precipitated in various compositions glass of CaO-$SiO_2-P_2O_5$ system, were identified by XRD. E composition (CaO 49.4, $SiO_2\;36.8,\;P_2O_5$ 8.8 wt%) glass in which both apatite(($Ca_{10}(PO_4)_6O$ and $\beta$-wollastonite($CaSiO_3$) crystals would precipitate by heating, was selected as an experimental composition to prepare the glass ceramics with high bending strength and good bioactivity to the living bone. Glass powders of E composition were unidirectionally crystallized at $1050^{\circ}$C in the temperature-gadient furnace and the resultant glass ceramics were characterized. Bending strength of the glass ceramics was also measured. To investigate the bond forming ability between the glass ceramics and living bone tissue, soaking test of glass ceramics in simulated body fluid was carried out. Densed glass ceramics composed of apatite and $\beta$-wollastonite crystal were prepared by unidirectional crystallization under the optimum conditions. (2 0 2) plane of $\beta$-wollastonite crystals tended to grow perpendicularly to the crystallization direction. Average bending strength of this glass ceramics was 186.9 MPa, higher than that of the glass ceramics prepared by isothermal (not directional) crystallization In soaking test, a thin layer of apatite crystallite was formed on surface of the glass ceramics in 3 days. Apatite crystals formed on the glass ceramics could be act a role to make the chemical bond between the glass ceramics and living bone tissue.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.96-96
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• 2013

그래핀과 금속 결합에서 발생하는 접촉 저항을 줄이기 위한 목적으로, 소자 제작에 사용되는 $SiO_2$ 기판의 표면을 플라즈마를 사용하여 에칭하는 최적의 조건에 대해 연구하였다. 기존에 발표된 연구 결과에 따라 $SF_6$와 $O_2$를 섞어 플라즈마 처리를 하였고, 플라즈마 방전에 사용 된 두 가스의 혼합 비율을 조절함으로써 소자 제작에 적합한 조건을 찾고자 하였다. 플라즈마 처리 전후의 $SiO_2$ 기판의 표면 측정은 AFM (Atomic Force Microscope)을 사용하였고, 단면은 SEM(Scanning Electron Microscope)을 통해 확인하였다.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.878-883
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• 1998

The methane combustion reaction was conducted over Pb-ZSM-5 catalysts. ZSM-5 synthesized at low temperature and atomospheric pressure was used as a support. The change of methane conversion with $SiO_2/Al_2O_3$ molar ratio was tested. The methane conversions of the synthesized Pb-ZSM-5 catalyst was compared with those of a commercial Pd-ZSM-5(PQ Co.) and $PdO/{\gamma}-Al_2O_3$. The methane conversion increased with the decrease in $SiO_2/Al_2O_3$ molar ratio. The combustion rate of methane also increased with the decrease in $SiO_2/Al_2O_3$ molar ratio. The synthesized Pb-ZSM-5 showed better methane conversion than that of the commercial one. It is found that a crucial factor in methane combustion reaction is oxygen adsorption strength on the catalysts.

• Journal of the Mineralogical Society of Korea
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• v.27 no.1
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• pp.1-15
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• 2014

Probing the electronic structures of crystalline Mg-silicates at high pressure is essential for understanding the various macroscopic properties of mantle materials in Earth's interior. Quantum chemical calculations based on the density functional theory are used to explore the atomic configuration and electronic structures of Earth materials at high pressure. Here, we calculate the partial density of states (PDOS) and O K-edge energy-loss near-edge structure (ELNES) spectra for $MgSiO_3$ perovskite at 25 GPa and 120 GPa using the WIEN2k program based on the full-potential linearized projected augmented wave (FP-LPAW) method. The calculated PDOS and O K-edge ELNES spectra for $MgSiO_3$ Pv show significant pressure-induced changes in their characteristic spectral features and relative peak intensity. These changes in spectral features of $MgSiO_3$ Pv indicate that the pressure-induced changes in local atomic configuration around O atoms such as Si-O, O-O, and Mg-O length can induce the significant changes on the local electronic structures around O atoms. The result also indicates that the significant changes in O K-edge features can results from the topological densification at constant Si coordination number. This study can provide a unique opportunity to understand the atomistic origins of pressure-induced changes in local electronic structures of crystalline and amorphous $MgSiO_3$ at high pressure more systematically.

• Korean Journal of Materials Research
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• v.5 no.6
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• pp.709-709
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• 1995

원거리 플라즈마 화학증착법을 이용하여 저온에서 이산화규소박막을 제조하였다. 본 연구 에서는 공정변수인 기판의 온도, 반응기체의 조성 및 분압과 플라즈마 전력에 따른 산화막의 재료적인 물성을 평가하였다. XPS결과에서 산화막은 양론비(O/Si=2)보다 약간 적어 실리콘이 많이 함유된 막으로 나타났다. 이 경우 굴절율과 ESR분석에 의해 미결합된 실리콘의 양이 증가함을 알 수 있었다. SIMS분석에 의해 미량의 질소성분이 계면에 존재하는 것과 실리콘 미결함을 관찰하였다. FT-IR로부터 막내 수소량을 정량화하였으며 결합각 분포는 200℃이상에서 열산화막과 비슷한 값을 얻었다. 하지만 열산화막에 비해 높은 식각율을 보여 계면 스트레스에 의해 막내의 결합력이 약해진 것으로 생각된다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.778-783
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• 1998

Film characteristics of thin ONO dielectric layers for MONOS(metal-oxide-nitride-oxide-semiconductor) EEPROM was investigated by TEM, AES and AFM. Seocnd derivative spectra of Auger Si LVV overlapping peak provide useful information fot chemical state analysis of superthin film. The ONO film with dimension of tunnel oxide 23$\AA$, nitride 33$\AA$, and blocking oxide 40$\AA$ was fabricated. During deposition of the LPCVD nitride film on tunnel oxide, this thin oxide was nitrized. When the blocking oxide was deposited on the nitride film, the oxygen not only oxidized the nitride surface, but diffused through the nitride. The results of ONO film analysis exhibits that it is made up of $SiO_2$ (blocking oxide)/O-rich SiON(interface)/N-rich SiON(nitride)/ O-rich SiON(tunnel oxide)