• 대한화학회지
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• 제64권2호
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• pp.61-66
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• 2020

In this study, we investigate the structural and electronic properties of copper oxide clusters, Cu_nO_n (n = 9 - 15). To find the lowest energy structures of copper oxide clusters, we use ReaxFF and density functional theory calculations. We calculate many initial copper oxide clusters using ReaxFF quickly. Then we calculate the lowest energy structures of copper oxide clusters using B3LYP/LANL2DZ model chemistry. We examine the atomization energies per atom, average bond angles, Bader charges, ionization potentials, and electronic affinities of copper oxide clusters. In addition, the second difference in energies is investigated for relative energies of copper oxide clusters.

• Advances in nano research
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• 제4권2호
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• pp.113-128
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• 2016

Luminescent metallic clusters have attracted great interest due to their unique optical, electronic and chemical features. Comparing with intensively studied Au and Ag Clusters, Cu clusters are superior in the aspects of cost and wide industrial demanding. However, tiny copper clusters are extremely prone to aggregate and undergo susceptibility of oxidation, thereby the synthesis of fluorescent zero valent copper clusters is rather challenging. In this review, synthetic strategies towards luminescent copper clusters, including macromolecule-protection and micro molecule-capping, have been systematically surveyed. Both "bottom-up" and "top-down" synthetic routes are found to be effective in fabricating luminescent copper clusters, some of which are quite stable and possess decent luminescence quantum yields. In general, the synthesis of fluorescent copper clusters remains at its infant stage. A great deal of effort on developing novel and economic synthetic routes to produce bright and stable copper clusters is highly expected in future.

• Transactions on Electrical and Electronic Materials
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• 제4권1호
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• pp.1-6
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• 2003

We have studied the size confinement effect on the properties of melting-like transition of small icosahedral copper clusters using a classical molecular dynamics simulation based on a well fitted empirical potential. We investigated the caloric curves of icosahedron nanoclusters and the significant depression in the melting temperatures of the copper nanoclusters was compared with that of the bulk copper. A structural transitions from decahedral to icosahedral shapes were shown. As the cluster size increased, the melting temperature increased, and the latent heat increased but seem to be saturated. However, the specific heat was unrelated to the cluster size.

• Advances in materials Research
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• 제1권2호
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• pp.109-113
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• 2012

Electromigration-induced void evolutions in typical upper and lower layer dual-inlaid Copper (Cu) interconnect structures were simulated by applying a phenomenological model resorting to Monte Carlo based simulations, which considers redistribution of heterogeneously nucleated voids and/or pre-existing vacancy clusters at the Copper/dielectric cap interface during electromigration. The results indicate that this model can qualitatively explain the electromigration-induced void evolutions observations in many studies reported by several researchers heretofore. These findings warrant need to re-investigate technologically important electromigration mechanisms by developing rigorous models based on similar concepts.

• 대한화학회지
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• 제60권4호
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• pp.239-244
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• 2016

안정된 구조로 알려진 산화구리 클러스터(Cu_nO_n, n = 1 - 8)를 이용하여 구리 원자를 규소 원자로 치환하여 Cu_mSiO_m+1 (m = 0 - 7)의 안정된 구조를 최적화하였다. B3LYP/LANL2DZ의 이론수준에서 계산하였으며 중성과 하전된 안정된 구조를 계산하였다. 구리원자를 규소 원자로 치환으로 인한 구조적 변화를 위해 결합길이, 결합각, 그리고 Mulliken 전하를 계산하였다. 클러스터의 상대적 안정성을 구하기 위해 second differences in energy를 계산하였고 전기적 특성을 연구하기 위해 이온화 에너지와 전자친화도 계산을 수행하였다.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3843-3846
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• 2013

• Journal of Magnetics
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• 제19권1호
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• pp.68-71
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• 2014

Copper doped Zinc Oxide nanofilms were prepared using a simple and low cost wet chemical method. The microstructures, phase structure, Raman shift and optical absorption spectrum as well as magnetization were investigated for the nanofilms. Room temperature ferromagnetism has been observed for the nanofilms. Structural analyses indicated that the films possess wurtzite structure and there are no segregated clusters of impurity phase appreciating. The results show that the ferromagnetism in Copper doped Zinc Oxide nanofilms is driven either by a carrier or defect-mediated mechanism. The present work provides an evidence for the origin of ferromagnetism on Copper doped Zinc Oxide nanofilms.

• Bulletin of the Korean Chemical Society
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• 제29권12호
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• pp.2540-2542
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• 2008

• Mycobiology
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• 제42권4호
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• pp.427-431
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• 2014

Mitochondrial protein Nfu1 plays an important role in the assembly of mitochondrial Fe-S clusters and intracellular iron homeostasis in the model yeast Saccharomyces cerevisiae. In this study, we identified the Nfu1 ortholog in the human fungal pathogen Cryptococcus neoformans. Our data showed that C. neoformans Nfu1 localized in the mitochondria and influenced homeostasis of essential metals such as iron, copper and manganese. Marked growth defects were observed in the mutant lacking NFU1, which suggests a critical role of Nfu1 in Fe-S cluster biosynthesis and intracellular metal homeostasis in C. neoformans.

• 한국진공학회지
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• 제7권2호
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• pp.118-126
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• 1998

반도체 접촉구를 메우기 위하여 소오스의 직진성을 향상시키기 위한 연구를 수행하 였다. 이온화클러스터빔 증착법을 이용하는 동시에 셀의 구조를 개선하여 직진성 향상을 도 모하였다. 중성클러스터 만으로 구리를 증착할 경우 직진성은 매우 우수하였으나 소오스의 표면 이동이 적어 박막은 주상형으로 성장하며 측벽에의 증착은 거의 일어나지 않았으며 성 장에 따라 그림자효과로 인한 단차에서의 벽개가 관찰되었다. 그러나, 가속전압을 인가하여 전하를 띤 클러스터를 형성시켜 증착하였을 때 주상형 성장 모드는 사라졌으며, 직경 0.5$\mu$ m, aspect ratio 2의 접촉구에서 완벽한 바닥면의 도포성을 나타내었고, 측벽에의 증착성도 향상되어 막의 연결성이 개선되었다. 이로써 이온화 클러스터빔 증착법이 직진성을 향상시 켜 작은 접촉구의 메움을 향상시킬수 있는 물리적 증착 방법임을 확인하였다.