• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.77-80
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• 2007

To increase the capacity of hydrogen adsorption, transition metals were adopted as catalyst. The PAN-based CNFs involving transition metal were obtained by electrospinning method and heat treatment. To study the surface of carbon fibers, SEM analysis was conducted. The mass of transition metals were spreaded or covered among CNFs. XRD and EDX analysis were used to confirm transition metals on the surface of carbon fibers. Volumetric method was used for studying the capacity of hydrogen adsorption on the carbon fibers involving transition metals. In this study. vanadium has the best characteristics among chromium, titanium, and copper for hydrogen adsorption.

• 통합자연과학논문집
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• 제1권3호
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• pp.189-191
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• 2008

Alkylation, carbonylation and cyclization reaction using transition metal(or inner-) complexes as reducing agents or catalysts were investigated.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1996년도 재료학회 추계학술발표회
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• pp.44-44
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• 1996

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2028-2030
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• 2005

The electrical conductivity of manganese oxide and complex manganese oxide produced by anodic deposition method was measured. The additive transition metal is Cu, Co and Fe. The transition metals like as Cu, Co and Fe improved electrical conductivity of complex manganese oxide compared with manganese oxide. This is coincide with the results of molecular orbital calculation by DV-Xa.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.82.1-82.1
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• 2008

• 대한화학회지
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• 제35권6호
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• pp.645-652
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• 1991

몇 가지 전이금속이온(Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ)) 및 후전이금속이온(Cd(Ⅱ), Hg(Ⅱ), Pb(Ⅱ))과 $N_2O_3$계 거대고리 리간드인 1,15-diaza-3,4 : 12,13-dibenzo-5,8,11-trioxacyclooctadecane 사이에 형성되는 착물의 안정도 상수를 수용액에서 전위차 적정법으로 결정하였다. 각 착물의 안정도 상수$(logK_f)$는 $25^{\circ}$C에서 Co(Ⅱ): 3.83, Ni(Ⅱ) : 4.56, Cu(Ⅱ) : 7.74, Zn(Ⅱ) : 4.98, Cd(Ⅱ) : 3.91, Hg(II) : 14.87, Pb(Ⅱ) : 6.65이었다. 전이금속착물의 안정도 순위는 Williams-Irving 서열인 Co(Ⅱ) < Ni(Ⅱ) < Cu(Ⅱ) < Zn(Ⅱ)와 일치하였고, 후전이금속착물의 안정도는 Cd(Ⅱ) < Pb(Ⅱ) < Hg(Ⅱ)이 순위이었다. 한편 메탄올 용액에서 자외-가시선이온과 리간드가 1:1인 조성을 가졌으나, Ni(Ⅱ), 착물은 1:1과 1:2 두 가지 조성을 가질 수 있음을 알았으며, 또 디메틸술폭시드 용액에서 $^1H-$와 $^{13}C-$핵자기공명스펙트럼을 분석하여 후전이금속이온 착물은 주로 리간드의 질소원자가 결합에 기여함을 알았다. Cu(Ⅱ)와 Zn(Ⅱ)이 고체착물은 원소분석, 전기전도도, 자화율 측정, 자외-가시선 및 적외선 스펙트럼분석 등으로 Cu(Ⅱ) 착물은 일그러진 팔면체, 그리고 Zn(Ⅱ) 착물은 사면체 구조를 이루고 있는 것으로 예측되었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.19.2-19.2
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• 2011

The $(Sr_{0.75},\;La_{0.25})TiO_3$ (SLTO) ultra-thin films with various thicknesses have been grown on Ti-O terminated $SrTiO_3$(100) substrate using Laser-Molecular Beam Epitaxy (Laser MBE). By monitoring the in-situ specular spot intensity oscillation of reflection high energy electron diffraction (RHEED), we controlled the layer-by-layer film growth. The film structure and topography were verified by atomic force microscopy (AFM) and high resolution thin film x-ray diffraction by the synchrotron x-ray radiation. We have also investigated the electronic band structure using x-ray absorption spectroscopy (XAS). The ultra thin SLTO film exhibits thickness driven metal-insulator transition around 8 unit cell thickness when the film thickness progressively reduced to 2 unit cell. The SLTO thin films with an insulating character showed band splitting in Ti $L_3-L_2$ edge XAS spectrum which is attributed to Ti 3d band splitting. This narrow d band splitting could drive the metal-insulator transition along with Anderson Localization. In optical conductivity, we have found the spectral weight transfer from coherent part to incoherent part when the film thickness was reduced. This result indicates the possibility of enhanced electron correlation in ultra thin films.

• Applied Science and Convergence Technology
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• 제23권6호
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• pp.317-327
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• 2014

In order to develop nano-devices with much lower power consumption for beyond-CMOS applications, the fundamental understanding and precise control of the electronic properties of ultrathin transition metal oxide (TMO) films are strongly required. The metal-insulator transition (MIT) is not only an important issue in solid state physics, but also a useful phenomenon for device applications like switching or memory devices. For potential use in such application, the electronic structures of MIT, observed for TMO nano-structures, have been investigated using a synchrotron radiation angle-resolved photoelectron spectroscopy system combined with a laser molecular beam epitaxy chamber and a scanning photoelectron microscopy system with 70 nm spatial resolution. In this review article, electronic structures revealed by soft X-ray nano-spectroscopy are presented for i) polarity-dependent MIT and thickness-dependent MIT of TMO ultrathin films of $LaAlO_3/SrTiO_3$ and $SrVO_3/SrTiO_3$, respectively, and ii) electric field-induced MIT of TMO nano-structures showing resistance switching behaviors due to interfacial redox reactions and/or filamentary path formation. These electronic structures have been successfully correlated with the electrical properties of nano-structured films and nano-devices.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2002년도 추계국제학술대회
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• pp.155-155
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• 2002

Ambient urban particulate matters contain various transition metals. When the particulate matters are inhaled into the lung, not all but some part of metals from the particles might be mobilized to participate in a reaction that can damage various biomolecules, such as DNA and proteins. The dust particle size as well as organic acids may influence the metal mobilization. Thus, the mobilization of the metal from SRM1648 (NIST, USA) and urban particulate matters (PM2.5 and PM10) was measured in the presence of artificial or biological chelator with or without reductant. The degree of the mobilization was higher with the artificial or biological chelator than the control with saline. In some cases, a reductant increased the mobilization as much as about 5 times the control without the reductant. Especially, the mobilization of Fe was greatly influenced by the presence of reductants. In general, the degree of the mobilization of the transition metal was higher with PM2.5 than with PM10. Therefore, it is expected that, considering the previously known toxicities of the transition metals, the PM2.5 is more damaging to various biomolecules than PM10. The results also suggest that not the total amount but the mobilizable fraction of the metal in the dust particles should be considered with regard to the toxicity of the urban particulate matters.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.573-573
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• 2012

High quality $VO_2$ thin films were successfully grown on GaN substrate by optimizing oxygen partial pressure during the growth using RF sputtering technique. The $VO_2$ thin film grown on GaN substrate exhibited an unusual metal insulator transition behavior, which was known to be observed only either in doped sample or under uniaxial stress. Raman spectra also confirmed that metal insulator transition occurred from monoclinic M1 to rutile R phase via monoclinic M2 phase with increasing temperature. We believe that large lattice mismatch between $VO_2$ and GaN substrate may cause M2 phase to be thermodynamically stable. Optical transmittance and its electrical switching behavior were carefully investigated to elucidate the underlying physics of its metal insulator transition behavior. This study may lead to a unique opportunity to better understand the growth mechanism of M2 phase dominant $VO_2$ thin films.