• Journal of the Korean Electrochemical Society
• /
• v.8 no.3
• /
• pp.125-129
• /
• 2005

We have investigated the electrochemical factors affecting the magnetic properties of hard magnetic CoP nanowires and soft magnetic CoFe nanowires fabricated by ac electrodeposition into self-made AAO(anodic aluminum oxide) nano-templates. AAO template having nano scale pores of high aspect ratio has been prepared through 2-step anodizing of aluminum foil in sulfuric acid. Hard Magnetic properties of CoP nanowires were highly conditional on the applied ac potential which could be a decisive factor to make CoP nanowires made up of either pure hcp crystals or a mixture of hop crystals and fcc crystals. On the contrary to CoFe films, there was no anomalous codeposition in the electrodeposition of soft magnetic CoFe nanowires which exhibited their best saturation magnetization of 238 emu/g at the composition of $Co_{30}Fe_{70}$.

• Journal of the Korean Ceramic Society
• /
• v.49 no.6
• /
• pp.648-653
• /
• 2012

Hybridization of dense ceramic membranes for hydrogen separation with an electronically conductive metallic phase is normally utilized to enhance the hydrogen permeation flux and thereby to increase the production efficiency of hydrogen. In this study, we developed a nickel and proton conducting oxide ($BaCe_{0.9}Y_{0.1}O_{3-{\delta}}$: BCY) based cermet (ceramic-metal composites) membrane. Focused on the general criteria in that the hydrogen permeation properties of a cermet membrane depend on its microstructural features, such as the grain size and the homogeneity of the mix, we tried to optimize the microstructure of Ni-BCY cermets by controlling the fabrication condition. The Ni-BCY composite powder was synthesized via a solid-state reaction using $2NiCO_3{\cdot}3Ni(OH)_2{\cdot}4H_2O$, $BaCeO_3$, $CeO_2$ and $Y_2O_3$ as a starting material. To optimize the mixing scale and homogeneity of the composite powder, we employed a high-energy milling process. With this high-energy milled composite powder, we could fabricate a fine-grained dense membrane with an excellent level of mixing homogeneity. This controlled Ni-BCY cermet membrane showed higher hydrogen permeability compared to uncontrolled Ni-BCY cermets created with a conventionally ball-milled composite powder.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.881-883
• /
• 2005

In case is below length 100nm of gate, various kinds problem can be happened with by threshold voltage change of device, occurrence of leakage current by tunneling because thickness of oxide by 1.5nm low scaling is done and doping concentration is increased. SiO$_2$ dielectric substance can not be used for gate insulator because is expected that tunneling current become 1A/cm$^2$ in 1.5nm thickness low. In this paper, devised double gate MOSFET(DGMOSFET) to decrease effect of leakage current by this tunneling. Therefore, could decrease effect of these leakage current in thickness 1nm low of SiO$_2$ dielectric substance. But, very big gate insulator of permittivity should be developed for develop device of nano scale.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.11
• /
• pp.1241-1245
• /
• 2004

Continuous physical vapor deposition (PVD) method is one of many processes to fabricate long length coated conductor which is required for successful large-scale application of superconducting power devices. Three film deposition systems (pulsed laser deposition, sputtering, and evaporation) equipped with reel-to-reel(R2R) metal tape moving apparatus were installed and used to deposit multi-layer oxide thin films. Both RABiTS and IBAD texture templates are used. IBAD template consists of CeO$_2$(PLD)/YSZ(IBAD) on stainless steel(SS) metal tape, and RABiTS template has the structure of CeO$_2$/YSZ/Y$_2$O$_3$ which was continuously deposited on Ni-alloy tape using R$_2$R evaporation and DC reactive sputtering in a deposition system designed to do both processes. 0.4 m-long coated conductor with Ic(77 K) of 34 A/cm was fabricated using RABiTS template. 0.5 m and 1.1 m-long coated conductor with Ic(77 K) of 41 A/cm and 26 A/cm were fabricated using IBAD template.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.240.2-240.2
• /
• 2013

The device scale of flash memory was confronted with quantum mechanical limitation. The next generation memory device will be required a break-through for the device scaling problem. Especially, graphene is one of important materials to overcome scaling and operation problem for the memory device, because ofthe high carrier mobility, the mechanicalflexibility, the one atomic layer thick and versatile chemistry. We demonstrate the hybrid memory consisted with the metal-oxide quantum dots and the mono-layered graphene which was transferred to $SiO_2$ (5 nm)/Si substrate. The 5-nm thick secondary $SiO_2$ layer was deposited on the mono-layered graphene by using ultra-high vacuum sputtering system which base pressure is about $1{\times}10^{-10}$ Torr. The $In_2O_3$ quantum dots were distributed on the secondary $SiO_2$2 layer after chemical reaction between deposited In layer and polyamic acid layer through soft baking at $125^{\circ}C$ for 30 min and curing process at $400^{\circ}C$ for 1 hr by using the furnace in $N_2$ ambient. The memory devices with the $In_2O_3$ quantum dots on graphene monolayer between $SiO_2$ thin films have demonstrated and evaluated for the application of next generation nonvolatile memory device. We will discuss the electrical properties to understating memory effect related with quantum mechanical transport between the $In_2O_3$ quantum dots and the Fermi level of graphene layer.

• Journal of Life Science
• /
• v.12 no.1
• /
• pp.61-66
• /
• 2002

This study were constructed to investigate effects of duck's egg oil on antitumor agent or a new natural immunomodulator. To obtained the aboved objectives, Duck's egg oil was purified the large scale from Duck. Duck's egg oil was accelerated the increasing reaction of mouse spleen cells, while inhibited to increase the YAC-cells. However, there is no significance the rate of CD4'/CD8'cell. The normal rate of CD4'-T and CD8'-T cells were accelerated the higher rate than that normal mouse group, and Duck's egg oil feeding mice showed a significant enhancement of expression of IL-2 receptors, an increase of numbers of CD4+ T cells, CD8+ T cells. Otherwise, Duck's egg oil stimulated the production of NO from peritoneal macrophages and the production of TNF-a and also significantly accelerated in the spleen mice. On the other hands, lung localization of B16F10 melanoma cells inhibited by Duck's egg oil. These results found that Duck's egg oil is useful new functional materials as antitumor agent or immunomodulator.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.255-255
• /
• 2010

Recently, nonvolatile memories (NVM) of various types have been researched to improve the electrical performance such as program/erase voltages, speed and retention times. Also, the charge trap memory is a strong candidate to realize the ultra dense 20-nm scale NVM. Furthermore, the high charge efficiency and the thermal stability of SiC nanocrystals NVM with single $SiO_2$ tunnel barrier have been reported. [1-2] In this study, the SiC charge trap NVM was fabricated and electrical properties were characterized. The 100-nm thick Poly-Si layer was deposited to confined source/drain region by using low-pressure chemical vapor deposition (LP-CVD). After etching and lithography process for fabricate the gate region, the $Si_3N_4/SiO_2/Si_3N_4$ (NON) and $SiO_2/Si_3N_4/SiO_2$ (ONO) barrier engineered tunnel layer were deposited by using LP-CVD. The equivalent oxide thickness of NON and ONO tunnel layer are 5.2 nm and 5.6 nm, respectively. By using ultra-high vacuum magnetron sputtering with base pressure 3x10-10 Torr, the 2-nm SiC and 20-nm $SiO_2$ were successively deposited on ONO and NON tunnel layers. Finally, after deposited 200-nm thick Al layer, the source, drain and gate areas were defined by using reactive-ion etching and photolithography. The lengths of squire gate are $2\;{\mu}m$, $5\;{\mu}m$ and $10\;{\mu}m$. The electrical properties of devices were measured by using a HP 4156A precision semiconductor parameter analyzer, E4980A LCR capacitor meter and an Agilent 81104A pulse pattern generator system. The electrical characteristics such as the memory effect, program/erase speeds, operation voltages, and retention time of SiC charge trap memory device with barrier engineered tunnel layer will be discussed.

• Korean Journal of Metals and Materials
• /
• v.46 no.7
• /
• pp.458-463
• /
• 2008

High purity Fe thin films were prepared by the ion beam deposition method with $^{56}Fe^{+}$ions on the Si substrate at the room temperature. The Fe thin films were deposited at the ion energy of 50 eV and 100 eV. Microstructural properties were investigated on the atomic scale using high-resolution transmission electron microscopy (HRTEM). It was found that the Fe thin film obtained with the energy of 50 eV having an excellent corrosion resistance consists of the amorphous layer of ~15 nm in thickness and the bcc crystalline layer of about 30 nm in grain size, while the thin film obtained with the energy of 100 eV having a poor corrosion resistance consists of little amorphous layer and the defective crystalline layer. Furthermore the crystal structures and arrangements of the oxide layers formed on the Fe thin films were analyzed by processing of the HRTEM images. It was concluded that the corrosion behavior of Fe thin films relates to the surface morphology and the crystalline structure as well as the degree of purification.

• Clean Technology
• /
• v.24 no.4
• /
• pp.357-364
• /
• 2018

Studies on the production of biogas from third generation biomass, such as micro- and macroalgae, have been conducted through experiments of various scales. In this paper, we investigated the feasibility of commercialization of integrated combined heat and power (CHP) production using biogas derived from macroalgae, i.e., seaweed biomass. For this purpose, an integrated CHP plant of industrial scale, consisting of solid oxide fuel cells, gas turbine and organic Rankine cycle, was designed and simulated using a commercial process simulator. The cost of each equipment in the plant was estimated through the calculated heat and mass balances from simulation and then the techno-economic analysis was performed. The designed integrated CHP process produces 68.4 MW of power using $36ton\;h^{-1}$ of biogas from $62.5ton\;h^{-1}$ (dry basis) of brown algae. Based on these results, various scenarios were evaluated economically and the levelized electricity cost (LEC) was calculated. When the lifetime of SOFC is 5 years and its stack price is $$225kW^{-1}$, the LEC was 12.26 ¢ $kWh^{-1}$, which is comparable to the conventional fixed power generation.

• Korean Journal of Metals and Materials
• /
• v.46 no.10
• /
• pp.646-651
• /
• 2008

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical structural materials. It is essential to choose the optimum material for the process equipment handling molten salt. IN713LC is one of the candidate materials proposed for application in electrolytic reduction process. In this study, yttria-stabilized zirconia (YSZ) top coat was applied to a surface of IN713LC with an aluminized metallic bond coat by an optimized plasma spray process, and were investigated the corrosion behavior at $675^{\circ}C$ for 216 hours in the molten salt $LiCl-Li_2O$ under an oxidizing atmosphere. The as-coated and tested specimens were examined by OM, SEM/EDS and XRD, respectively. The bare superalloy reveals obvious weight loss, and the corrosion layer formed on the surface of the bare superalloy was spalled due to the rapid scale growth and thermal stress. The top coatings showed a much better hot-corrosion resistance in the presence of $LiCl-Li_2O$ molten salt when compared to those of the uncoated superalloy and the aluminized bond coatings. These coatings have been found to be beneficial for increasing to the hot-corrosion resistance of the structural materials for handling high temperature lithium molten salts.