• Journal of Powder Materials
• /
• v.20 no.1
• /
• pp.53-59
• /
• 2013

Fe-TiC composite powder was fabricated via two steps. The first step was a high-energy milling of FeO and carbon powders followed by heat treatment for reduction to obtain a (Fe+C) powder mixture. The optimal condition for high-energy milling was 500 rpm for 1h, which had been determined by a series of preliminary experiment. Reduction heat-treatment was carried out at $900^{\circ}C$ for 1h in flowing argon gas atmosphere. Reduced powder mixture was investigated by X-ray Diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM) and Laser Particle Size Analyser (LPSA). The second step was a high-energy milling of (Fe+C) powder mixture and additional $TiH_2$ powder, and subsequent in-situ synthesis of TiC particulate in Fe matrix through a reaction of carbon and Ti. High-energy milling was carried out at 500 rpm for 1 h. Heat treatment for reaction synthesis was carried out at $1000{\sim}1200^{\circ}C$ for 1 h in flowing argon gas atmosphere. X-ray diffraction (XRD) results of the fabricated Fe-TiC composite powder showed that only TiC and Fe phases exist. Results from FE-SEM observation and Energy-Dispersive X-ray Spectros-copy (EDS) revealed that TiC phase exists uniformly dispersed in the Fe matrix in a form of particulate with a size of submicron.

• Aerospace Engineering and Technology
• /
• v.7 no.2
• /
• pp.110-116
• /
• 2008

This paper gives a brief summary of the TVC battery design description, specifications and test results. The TVC battery for KSLV-I upper stage contains 168 Sony l8650VT high power lithium-ion cells. It configured as 2 strings in parallel, with each string containing 84 series connected cells. This allows to meet nominal 270V voltage and capacity requirements specified for the mission of the Thrust Vector Control(TVC) system. The loads profile of the TVC system has short duration, high current pulse. To power such a system with minimal mass, the battery employed l8650VT Cells. This cell is specifically designed for high rate applications and is capable of a 10C continuous discharge.

• 한국초전도학회:학술대회논문집
• /
• 2009.07a
• /
• pp.76-76
• /
• 2009

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.2
• /
• pp.399-404
• /
• 2004

This study was conducted to investigate the effect of monosodium glutamate (MSG) and fermentation methods (C-I; fermented for 5 days at 1$0^{\circ}C$ after 2$0^{\circ}C$ fermentation for 2 days, C-II; fermented for 7 days at 1$0^{\circ}C$, M-I; kimchi with MSG fermented for 5 days at 1$0^{\circ}C$ after 2$0^{\circ}C$ fermentation for 2 days, M-II; kimchi with MSG fermented for 7 days at 1$0^{\circ}C$ on fermentation and free amino acid content. Fermentation of M-I and M-II was slightly delayed compared to C-I and C-II. Total microbe of C-I and C-IIwere lower than those of M-I and M-II, and lactic acid bacteria of C-I and C-II were lower than those of M-I and M-II respectively. The major free amino acids were alanine, asparagine, homocystine and valine in C-I, especially, glutamic acid and ornithine were high in C-II. Homocystine, alanine, asparagine and valine in M-I, glutamic acid, alanine, hydroxyproline, asparagine, homocystine, ornithine and valine were the major free amino acid in M-II, respectively. The sour taste of M-I and M-II was lower than those of C-I and C-II, respectively, and the effect of delaying fermentation at 1$0^{\circ}C$ did not showed in the C-I and M-I. The crispy taste of the M-I and M-II was higher than those of C-I and C-II, which was the opposite results of sour taste. Palatable and overall taste of M-I and M-II were higher than those of C-I and C-II, respectively These results suggest that the MSG in kimchi affect not only increment of free amino acid content but also shelf-life and taste improvement, and continuous fermentation at 1$0^{\circ}C$ also enhance the content of free amino acid and shelf-life of kimchi.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.4 no.4
• /
• pp.61-68
• /
• 1995

TiC-Al2O3 composite ceramics has high hardness, high strength, high wear and corrosion resistance. Therefore, composite ceramics have been concerned significantly with some excellent properties and many functions as new industrial materials to the industry at large. In present research, experiments are carried out to obtain the machinability and machining properties by EDM. As a result, the most suitable machining conditions of TiC-Al2O3 composite ceramics was that the pulse duration is 10-60$mutextrm{s}$, the peak current is 10-16A. The machining speed and the wear of the tool electrode increased with the increase in peak current.

• Journal of Life Science
• /
• v.27 no.8
• /
• pp.879-887
• /
• 2017

It is well established that brain-derived neurotrophic factor (BDNF) is expressed not only in the brain but also in skeletal muscle, and is required for normal neuromuscular system function. Histone deacetylases (HDACs) and insulin-like growth factor-I (IGF-I) are potent regulators of skeletal muscle myogenesis and muscle gene expression, but the mechanisms of HDAC and IGF-I in skeletal muscle-derived BDNF expression have not been examined. In this study, we examined the effect of IGF-I and suberoylanilide hydroxamic acid (SAHA), a pan-HDAC inhibitor, on BDNF induction. Proliferating or differentiating C2C12 skeletal muscle cells were treated with increasing concentrations (0-50 ng/ml) of IGF-I in the absence or presence of $5{\mu}M$ SAHA for various time periods (3-24 hr). Treatment of C2C12 cells with IGF-I resulted in a dose- and time-dependent decrease in BDNF mRNA expression. However, inhibition of HDAC led to a significant increase in the expression of BDNF mRNA levels. In addition, immunocytochemistry revealed high BDNF protein levels in undifferentiated C2C12 skeletal muscle cells, whether untreated, IGF-I-treated, or exposed to SAHA. These results represent the first evidence that IGF-I can suppress the mRNA and protein expression of BDNF; conversely, SAHA attenuates the effects of IGF-I. Consequently, SAHA upregulates BDNF expression in C2C12 skeletal muscle cells.

• Nuclear Medicine and Molecular Imaging
• /
• v.41 no.2
• /
• pp.118-131
• /
• 2007

Neurotransmitter imaging with radiopharmaceuticals plays major role for understanding of neurological and psychiatric disorders such as Parkinson's disease and depression. Radiopharmaceuticals for neurotransmitter imaging can be divided to dopamine transporter imaging radiopharmaceuticals and serotonin trnasporter imaging radiopharmaceuticals. Many kinds of new dopamine transporter imaging radiopharmcaeuticals has a tropane ring and they showed different biological properties according to the substituted functional group on tropane ring. After the first clinical trials with $[^{123}I]{\beta}-CIT$, alkyl chain substituent introduced to tropane ring amine to decrease time for imaging acquisition and to increase selectivity. From these results, $[^{123}I]PE2I$, [18F]FE-CNT, $[^{123}I]FP-CIT$ and $[^{18}F]FP-CIT$ were developed and they showed high uptake on the dopamine transporter rich regions and fast peak uptake equilibrium time within 4 hours after injection. $[^{11}C]McN$ 5652 was developed for serotonin trnasporter imaging but this compound showed slow kinetics and high background radioactivity. To overcome these problems, new diarylsulfide backbone derivatives such as ADAM, ODAM, AFM, and DASB were developed. In these candidates, $[^{11}C]AFM$ and $[^{11}C]DASB$ showed high binding affinity to serotonin transporter and fast in vivo kinetics. This paper gives an overview of current status on dopamine and serotonin transporter imaging radiopharmaceuitcals and the development of new lead compounds as potential radiopharmaceuticals by medicinal chemistry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.05a
• /
• pp.1-2
• /
• 2009

The high critical current ($I_c$, A) of SmBCO coated conductor in a magnetic field, the high production rate and the high material yield are promising for applications. The inhomogeneity of Ie at the long length coated conduct is very important problem for electric application. So we researched the reason of inhomogeneity of $I_c$ at long length tape prepared by batch type co-evaporation system called by EDDC. The long length SmBCO coated conductors were developed on $LaMnO_3/IBAD-MgO/Y_2O_3/Al_2O_3$/Hastelloy C276 template. The distribution of $I_c$ are from 0 to 397 A/cm at 77 K and self field. We have studied the microstructures of these films by using SEM, EDS and X-ray diffraction. The XRD and composition by EDS results of SmBCO film reveals subtle difference. But, the microscopic observation by SEM show the microcrack at the sample with low $I_c$.

• Progress in Superconductivity and Cryogenics
• /
• v.24 no.3
• /
• pp.57-61
• /
• 2022

One of the major applications of REBCO coated conductor (CC) tapes is in superconducting magnets or coils that are designed for high magnet fields. For such applications, the CC tapes were exposed to a high level of stresses which includes uniaxial tensile or transverse compressive stresses resulting from a large magnetic field. Thus, CC tapes should endure such mechanical load or deformation that can influence their electromechanical performance during manufacturing, cool-down, and operation. It has been reported that the main cause of critical current (I_c) degradation in CC tapes utilized in coil windings for superconducting magnets was the delamination due to transversely applied stresses. In most high-magnetic-field applications, the operating limits of the CC tapes will likely be imposed by the electromechanical properties together with its I_c dependence on temperature and magnetic field. In this study, we examined the influence of the transverse compressive stress on the I_c degradation behaviors in various commercially available CC tapes which is important for magnet design Four differently processed REBCO CC tapes were adopted to examine their I_c degradation behaviors under transverse compression using an anvil test method and a newly developed instantaneous I_c measurement system. As a result, all REBCO CC tapes adopted showed robustness against transverse compressive stresses for REBCO coils, notably at transverse compressive stresses until 250 MPa. When the applied stress further increased, different Ic degradation behaviors were observed depending on the sample. Among them, the one that was fabricated by the IBAD/MOCVD process showed the highest compressive stress tolerance.

• Journal of Sensor Science and Technology
• /
• v.8 no.6
• /
• pp.448-453
• /
• 1999

A Pd-SiC Schottky diode for detection of hydrogen gas operating at high temperature was explored. Hydrogen-sensing behaviors of Pd-SiC Schottky diode were analyzed as a function of hydrogen concentration and temperature by I-V and ${\Delta}I$-t methods under steady-state and transient conditions. The effect of hydrogen adsorption on the barrier height was investigated. Analysis of the steady-state kinetics using I-V method confirmed that the atomistic hydrogen adsorption process is responsible for the barrier height change in the diode.