• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.79-83
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• 2006

The first quantitative structure determination has been obtained for Cu(100)/glycine $(NH_2CH_3COOH)$. The molecule is adsorbed on the surface via two functional groups: the nitrogen of the amino group and one or both two oxygen atoms of the carboxylate group are bonded in near atop site. The Cu-N is tilted $5^{\circ}\pm4^{\circ}C$, away from the surface normal whilst the Cu-O is tilted by $9^{\circ}\pm2^{\circ}C$. The chemical bonding lengths are determined with $2.05\pm0.02\;{\AA}$ for both Cu-N and Cu-O. This bonding geometry is similar to that of glycine on Cu(110). A reanalysis of O Is from the Cu(110)$(2\times3)$pg-glycine show two oxygen atoms are inequivalent, with one being offset $0.29\;{\AA}$ more than the other.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.280-285
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• 2006

Adsorption characteristics of $H_{2}S$ on KOH impregnated activated carbon were evaluated using dynamic adsorption method in a fixed bed. The pore properties, including BET's specific surface area, pore volume, pore size distribution, and mean pore diameter of these KOH impregnated activated carbons, were characterized from $N_{2}$ adsorption/desorption isotherms. Adsorption equilibrium data were correlated with Langmuir and Freundlich isotherms. The adsorption of $H_{2}S$ onto the KOH impregnated activated carbon is better fitted by the Langmuir isotherm. An increase in the content of oxygen affects the performance of KOH impregnated activated carbon to the greatest extent.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.467-474
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• 2007

The palladium and gold nanoparticles containing PAN-based active carbon fiber (ACF) with a high specific surface area were prepared. Using the BET, TEM, FE-SEM, and XPS, their specific surface area and pore volume, pore structure, and the change in surface oxygen groups with time were analyzed and $SO_2$ adsorption performances were investigated. Because of the impregnating process, the micropore volume was mostly decreased from 95.5% to 30.5~43.7% compared with the total pore volume. And the change in surface oxygen groups with time was higher for the metal salt than the nanoparticles. Also, $SO_2$ breakthrough time of PAN-ACFs impregnated with Au nanoparticles and metal salts did not change compared with that of the non-impregnated PAN-ACF. But the PAN-ACF impregnated with Pd nanoparticles (100 ppm) showed good $SO_2$ adsorption performance as the breakthrough time of 880 sec. These results indicated that the $SO_2$ adsorption performance depended on the change in surface oxygen groups with time and the moderate impregnation of Pd nanoparticles on the PAN-ACF caused the increase in the $SO_2$ adsorption performance by a catalytic action.

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.23-28
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• 2024

Cesium is a potential toxic contaminant due to its high solubility, which allows it to easily penetrate the human body and potentially induce cancer or DNA mutations. In this study, oxygen functional groups were introduced on activated carbons (ACs) by ozone treatment to enhance the cesium adsorption capacity. As the ozone treatment time increased, the oxygen content on the ACs surface increased. Subsequently, the electrostatic interaction between ACs and cesium enhanced, resulting in higher cesium ion adsorption efficiency across all samples. In particular, the sample treated with ozone for 7 minutes at an internal ozone concentration of 50000 ppm had roughly 12% greater oxygen functional group content and the highest cesium removal effectiveness (97.6%). Meanwhile, samples treated for 5 minutes showed a 0.3% cesium removal rate difference compared to those treated for 7 minutes, which was caused by the surface chemical similarity of the two samples due to the reactive characteristics of ozone gas. However, the cesium adsorption performance of ozonated activated carbon seems to be mainly influenced by the amount of oxygen functional groups introduced to the surface, although the specific surface area and pore structure of the activated carbon are also important.

• Electrical & Electronic Materials
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• v.4 no.1
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• pp.65-72
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• 1991

본 논문은 전극의 표면상태가 기체방전의 전리성장과 특성에 미치는 영향에 관한 것으로 질소-산소 혼합가스중의 순수전극과 오손전극의 상태에서 전압-전류 특성과 글로우방전 개시전압을 측정하였다. 순수전극의 경우, 압력과 전극간의 거리의 곱이 8(Torr-cm)이하이고 산소의 혼입량이 0.005(%)이하일 때의 전리성장은 암류로부터 안정타운젠트방전을 거쳐 글로우방전으로 이행되었으며 글로우방전 개시전압은 거의 일정하였다. 동일의 전극표면상태에서 조차 방전개시전압은 산소혼입비에 의존하며 방전횟수에 따른 이의 변화는 산소의 함량이 0.1(%)부근에서 크게 나타났다. 방전횟수와 산소혼입량의 증가에 따른 방전개시전압의 상승은 주로 전극표면에서의 산소흡착층의 형성과 부착작용에 의한 NO, $O_{2}$, NO$_{2}$, $O_{3}$와 간은 부이온의 생성에 기인된 것으로 여겨진다.

• Journal of the Korean Chemical Society
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• v.46 no.2
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• pp.117-124
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• 2002

Counterflow oxidation was developed and evaluated for treatment of organics that adsorbed in/on granular activated carbon(GAC). This reaction is a method that destructs and removes organics adsorbed, at the same time, regenerates waste carbon, uti lizing a self-sustained flame which propagates itself ina direction counter to the oxygen flow. The results showed that the mass loss of carbon and flam temperature were strongly dependent on the flow rate of oxyen, adsorptive capability of regenerated carbon completely was recovered, as well as destrution and removal efficiency of thermally stable PCBs was achieved with the value of better than 99.99%.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.96-99
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• 1992

The microanalysics by the direct observation of 180 (P, a)'" nuclear reactions on tungsten (110) surfaceare investigated using a 2MeV Van de Graaff accelerator. This method allows the determination of very smallquantities of nuclei near the surface of samples. The yields increase with oxygen exposure. The oxygen coverage, 0, is 0.5 at 5 Langmuir and 1.0 at 15 Langmuir.5 Langmuir.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.250-252
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• 2006

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.167-167
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• 2008

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.36.2-36.2
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• 2011

최근 나노기술의 비약적인 발전을 바탕으로 그 동안 구현이 쉽지 않았던 마이크로-나노 단위의 생체모사(biomimetics) 기술이 큰 각광을 받고 있다. 그 중에서도 특히 연잎 효과(lotus-effect)로 대표되는 접촉각 $150^{\circ}$ 이상의 초소수성(superhydrophobicity) 표면 구현은 생물, 화학, 물질 등의 다양한 분야에 있어 큰 사용가치를 가지기 때문에 연구가 전세계적으로 활발히 진행되고 있다. 초소수성을 가지는 표면을 구현하기 위해서는 표면의 화학적인 조성을 변화시켜 표면의 거칠기를 증대시키는 방법과 표면에너지를 낮추는 방법으로 구분될 수 있으며, 이를 위해 표면에 나노구조체를 형성시켜 표면 거칠기를 증대시키는 방법과 silane 계열의 자가-형성 단일막(Self-assembled monolayer)을 코팅하여 표면에너지를 낮추는 방법이 사용되어 왔다. 그러나 표면에 나노구조체를 형성시키는 과정에서 비싼 공정 비용이 발생하며, 대면적 구현이 쉽지 않다는 단점이 있으며, silane 계열의 자가-형성 단일막의 경우에는 제거가 쉽지 않아 추후 다양한 소자에의 적용이 어렵다는 단점을 가지고 있다. 본 연구에서는 무전해 식각법(Aqueous Electroless Etching)을 이용하여 대면적으로 합성시킨 실리콘 나노와이어의 표면 산소 흡착 처리를 통해 $156^{\circ}$ 이상의 초소수성 표면을 구현하였다. 액상 기반으로 형성된 실리콘 나노와이어의 표면은 열처리 공정을 통해 OH-기에서 O-기로 치환되어 낮은 표면에너지를 가지게 되며, 낮아진 표면에너지와 산화과정에서 증대된 표면 거칠기를 통해 Wenzel-state의 초소수성 표면 성질을 보였다. 변화된 나노와이어의 표면 거칠기는 주사전자현미경 (FE-SEM)과 주사투과현미경 (HR-TEM)을 통해 관찰되었다. 또한, 나노와이어의 길이와 열처리 공정 조건에 따라 나노와이어의 표면을 접촉각 $0^{\circ}$의 초친수성(superhydrophilicity) 특성부터 접촉각 $150^{\circ}$ 이상의 초소수성 특성까지 변화시킬 수 있었으며, 나노와이어의 길이에 따라 표면 난반사율을 조절하여 90% 이상의 매우 높은 흡수율을 가지는 나노와이어 표면을 구현할 수 있었다. 이러한 산소 흡착법을 이용한 초소수성 표면 구현은 기존 자가-형성 단일막 코팅을 이용한 방법에 비해 소자 제작 및 활용에 있어 매우 유리하며, 바이오칩, 수광소자 등의 다양한 응용 분야에 적용 가능할 것으로 예상된다.