• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.11
• /
• pp.987-991
• /
• 2009

We report growth of vertically well-aligned zinc oxide (ZnO) nanorods on indium-tin oxide (ITO)/glass substrates using a simple aqueous solution method at low temperature via control of the ZnO seed layer morphology. ZnO nanoparticles acting as seeds are pre-coated on ITO-coated glass substrates. by spin coating to control distribution and density of the ZnO seed nanoparticles. ZnO nanorods were synthesized on the seed-coated substrates in a dipping process into a main growth solution. It was found that the alignment of ZnO nanorods can be effectively manipulated by the spin-coating speed of the seed layer. A grazing incidence X-ray diffraction pattern shows that the ZnO seed layer prepared using the higher spin-coating speed is of uniform seed distribution and a flat surface, resulting in the vertical growth of ZnO nanorods aligned toward the [0001] direction in the main growth process.

• Journal of the Korean Magnetics Society
• /
• v.1 no.2
• /
• pp.55-59
• /
• 1991

The temperature-dependent magnetization curves of amorphous Fe-Co-(Nd, Sm, Gd, Tb)-B alloys were measured using a vibrating sample magnetometer from 77 K up to 900 K. The spin wave stiffness constants and the range of the exchange interaction were calculated from the saturation magnetization values at 0 K. Curie temperatures and the Bloch coefficients estimated from the saturation magnetization curves. The low temperature dependence of magnetization is in good agreement with Bloch relation, $M_{s}(T)=M_{s}(O)(1-BT^{3/2}-CT^{5/2})$. The spin wave stiffness constant and the range of exchange interaction are decreased by substitution of heavy rare earth (Tb, Gd).

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.12 no.4
• /
• pp.66-75
• /
• 2013

The spin modulation is proposed with modulating frequency and amplitude simultaeously, and realized with the array sturcture easily located due to the nanometer size of the spintronics oscillator. In this paper, the dual-channel receiver is deisgned for detecting the spin modulated signal. Resultly, we confirmed the dual-channel recevier well detected the data sent through the spintronics oscillator array, and processed up to 200 kbps on each channel. Distance is limited up to 1 cm due to the low level signal under -60 dBm. The realized dual-channel receiver has the size of $56{\times}33mm^2$.

• Korean Journal of Materials Research
• /
• v.25 no.4
• /
• pp.171-176
• /
• 2015

We present the detection characteristics of nitrogen monoxide(NO) gas using p-type copper oxide(CuO) thin film gas sensors. The CuO thin films were fabricated on glass substrates by a sol-gel spin coating method using copper acetate hydrate and diethanolamine as precursors. Structural characterizations revealed that we prepared the pure CuO thin films having a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the NO gas sensing measurements that the p-type CuO thin film gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as $100^{\circ}C$. Additionally, these CuO thin film gas sensors were found to show reversible and reliable electrical response to NO gas in a range of operating temperatures from $60^{\circ}C$ to $200^{\circ}C$. It is supposed from these results that the p-type oxide semiconductor CuO thin film could have significant potential for use in future gas sensors and other oxide electronics applications using oxide p-n heterojunction structures.

• Journal of Ginseng Research
• /
• v.22 no.2
• /
• pp.96-101
• /
• 1998

This paper describes the determination of bulk density and the discrimination of internal structure of red ginseng by nuclear magnetic resonance (NMR). The 102 red ginseng roots were tested for bulk density. The NMR properties measured by NMR parameters such as spin-lattice relaxation time ($T_1$) and spin-spin relaxation time ($T_2$) were determined using the low field proton NMR analyzer. Bulk density of red ginseng root showed a highly negative significant correlation (r=-0.8934) with the value of $T_1$, but a highly positive significant correlation (r=0.7672 and 0.5909) with the value of T21 (short T2) and T22 (long T2), respectively. Multiple regression equation, Y=-0.0069.$T_1$+0.3044.$T_{21}$-0.0156.$T_{22}$-0.6368, using the MNR parameter values of 80 red ginseng roots can effectively predict the bulk density of 22 red ginseng roots with the correlation coefficient of 0.9396 and the standard error of 0.086. The differences in the internal structure of normal and inside white part of red ginseng were easily found by the signal intensity of NMR image based on magnetic properties of proton nucleus.

• Journal of the Korean Magnetics Society
• /
• v.22 no.3
• /
• pp.73-78
• /
• 2012

We calculated the electron spin resonance (ESR) line-profile function. The line-width of single-walled carbon nanotube (SWNT) was studied as a function of the temperature at a frequency of 9.5 GHz in the presence of external electromagnetic radiation. The temperature dependence of the line-widths is obtained with the projection operator method (POM) proposed by Argyres and Sigel. The scattering is little affected in the low-temperature region (T < 200 K). We conclude that the calculation process presented in this method is useful for optical transitions in SWNT.

• BMB Reports
• /
• v.46 no.3
• /
• pp.151-156
• /
• 2013

Phylogenetic and amino acid sequence analysis indicated that rice allene oxide synthase-1 (OsAOS1) is CYP74, and is clearly distinct from CYP74B, C and D subfamilies. Regio- and stereo-chemical analysis revealed the dual substrate specificity of OsAOS1 for (cis,trans)-configurational isomers of 13(S)- and 9(S)-hydroperoxyoctadecadienoic acid. GC-MS analysis showed that OsAOS1 converts 13(S)- and 9(S)-hydroperoxyoctadecadi(tri)enoic acid into their corresponding allene oxide. UV-Visible spectral analysis of native OsAOS1 revealed a Soret maximum at 393 nm, which shifted to 424 nm with several clean isobestic points upon binding of OsAOS1 to imidazole. The spectral shift induced by imidazole correlated with inhibition of OsAOS1 activity, implying that imidazole may coordinate to ferric heme iron, triggering a heme-iron transition from high spin state to low spin state. The implications and significance of a putative type II ligand-induced spin state transition in OsAOS1 are discussed.

• Journal of the Korean Ceramic Society
• /
• v.40 no.11
• /
• pp.1102-1105
• /
• 2003

The fiber drawing process induced defects in silica fiber have been investigated. This study has focused on the Oxygen Deficient Centers (ODCs) and E' centers induced by the fiberization process in low-OH silica fibers. To investigate those defects induced by the fiberization process, the optical absorption spectrum and Electron Spin Resonance (ESR) have both been employed. The concentration of Oxygen Deficient Centers (ODCs) and E' centers are increased by the fiber drawing process. The population of defects in the neck-down region has also been investigated. The most significant generation of defects during fiber drawing process has been shown to occur in this region of silica preform. The population of defects is higher on the edge region than in the center of neck-down region.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.11
• /
• pp.2214-2218
• /
• 2009

Dye-sensitized solar cell (DSC) has been considered as a possible alternative to current silicon based p-n junction photovoltaic devices due to its advantages of high efficiency, simple fabrication process and low production cost. Numerous researches for high efficient DSC in the various fields are under way even now. Among them, the compact layer, which prevents the back electron transfer between transparent conductive oxides and the redox electrolyte, is fabricated by various methods such as a ZnO dip-coating, $TiCl_4$ dip-coating, and Ti sputtering. In this study, we tried to fabricate the $TiO_2$ compact layer by the spin-coating method using aqueous $TiCl_4$ solution. The effect of the spin-coating method was checked as compared with conventional dip-coating method. As a result, DSC with a spin-coated compact layer had 33.4% and 6% better efficiency than standard DSC and DSC with a dip-coated compact layer.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2003.06a
• /
• pp.24-24
• /
• 2003

Metallic magnetoelectronic devices have studied intensively and extensively for last decade because of the scientific interest as well as great technological importance. Recently, the scientific activity in spintronics field is extending to the hybrid devices using ferromagnetic/semiconductor heterostructures and to new ferromagnetic semiconductor materials for future devices. In case of the hybrid device, conductivity mismatch problem for metal/semiconductor interface will be able to circumvent when the device operates in ballistic regime. In this respect, spin-valve transistor, first reported by Monsma, is based on spin dependent transport of hot electrons rather than electron near the Fermi energy. Although the spin-valve transistor showed large magnetocurrent ratio more than 300%, but low transfer ratio of the order of 10$\^$-5/ prevents the potential applications. In order to enhance the collector current, we have prepared magnetic tunneling transistor (MTT) with single ferromagnetic base on Si(100) collector by magnetron sputtering process. We have changed the resistance of tunneling emitter and the thickness of baser layer in the MTT structure to increase collector current. The high transfer ratio of 10$\^$-4/ range at bias voltage of more than 1.8 V, collector current of near l ${\mu}$A, and magnetocurrent ratio or 55% in Si-based MTT are obtained at 77K. These results suggest a promising candidate for future spintronic applications.