• Journal of the Korean institute of surface engineering
• /
• v.37 no.1
• /
• pp.58-63
• /
• 2004

The oxidation behavior of Ti-Nb alloys was studied in dry atmosphere. After vacuum arc melting and hot rolling treatment, Ti-Nb alloys were oxidized at $450^{\circ}C$∼$750^{\circ}C$. The oxidation behaviors between matrix and oxide scale were analyzed by SEM, XPS and XRD. Ti-Nb alloys had higher oxidation resistance than pure Ti at $750^{\circ}C$. XPS analysis of oxide film revealed that $TiO_2$ oxide was formed on the top of surface. The weight gains during the oxidation increase rapidly at temperature above $600^{\circ}C$ which obey the parabolic law.

• Nuclear Engineering and Technology
• /
• v.53 no.2
• /
• pp.562-571
• /
• 2021

In this work, we propose a new mechanistic model for the treatment of helium behaviour which includes the description of helium solubility in oxide fuel. The proposed model has been implemented in SCIANTIX and validated against annealing helium release experiments performed on small doped fuel samples. The overall agreement of the new model with the experimental data is satisfactory, and given the mechanistic formulation of the proposed model, it can be continuously and easily improved by directly including additional phenomena as related experimental data become available.

• Proceedings of the IEEK Conference
• /
• summer
• /
• pp.209-212
• /
• 2004

In this paper, The stress induced leakage currents of thin silicon oxides is investigated in the nano scale structure implementation for Soc. The stress and transient currents associated with the on and off time of applied voltage were used to measure the distribution of high voltage stress induced traps in thin silicon oxide films. The stress and transient currents were due to the charging and discharging of traps generated by high stress voltage in the silicon oxides. The channel current for the thickness dependence of stress current, transient current, and stress induced leakage currents has been measured in oxides with thicknesses between $41\square\;and\;113.4\square,$ which have the channel width x length 10x1um, respectively. The stress induced leakage currents will affect data retention and the stress current, transient current is used to estimate to fundamental limitations on oxide thicknesses. The weight value of synapse transistor was caused by the bias conditions. Excitatory state and inhitory state according to weighted values affected the channel current. The stress induced leakage currents affected excitatory state and inhitory state.

• Progress in Superconductivity and Cryogenics
• /
• v.20 no.2
• /
• pp.6-10
• /
• 2018

Removal of iron oxide scale from feed-water in thermal power plant can improve power generation efficiency. We have proposed a novel scale removal system utilizing High Gradient Magnetic Separation (HGMS). This system can be applied to high temperature and pressure area. We have conducted the lab-scale model experiments using ${\varphi}50mm$ filters and it demonstrated high removal efficiency in HGMS, but scale-up of the system is required toward practical use. In this study, we conducted a large scale mock-up HGMS experiment. We used the superconducting solenoidal magnet with ${\varphi}400mm$ bore and demonstrated that our HGMS system can achieve sufficient scale removal capacity that is required to introduce into both off-line and on-line system.

• Journal of The Korean Dental Society of Anesthesiology
• /
• v.6 no.2 s.11
• /
• pp.103-112
• /
• 2006

Background: The purpose of this study was to compare the clinical safety and effect with and without additional submucosal midazolam to oral chloral hydrate and hydroxyzine when used for pediatric conscious sedation in a clinical dental environment. Methods: Thirty one cases of pediatric conscious sedations were performed in this study. Selection criteria included good health (ASA I), under 6 years old, 20 kg of body weight, uncooperative behavior and the need for sedation to receive dental treatment including anesthesia and restorative or surgical procedure for at least two teeth. In each visit, patients were randomly assigned into one of two groups; CH group: chloral hydrate (60 mg/kg), hydroxyzine (1 mg/kg), CH-M group: chloral hydrate (60 mg/kg). hydroxyzine (1 mg/kg) and submucoal midazolam (0.1 mg/kg). 50% nitrous oxide-oxygen was maintained during the sedation period Sedations were monitored using a pulse oximeter for estimating pulse rate (PR) and percutaneous oxygen saturation ($SpO_2$). Behavior response rated using Houpt's scale and need of restraint was assessed every 2 minutes through 30 minutes of operative procedure reviewing the videotape recording. Evaluation of overall behavior success was performed using modified overall behavior rate of Houpt's scale. Data was analyzed using t-test. Results: PR and $SpO_2$ for both groups remained within the normal values. The mean scores for sleep and movement of CH-M group were higher than those of CH group (P < 0.05). There were no significant difference in mean score for crying between two groups. The mean scores of overall behavior of CH-M group was higher than those of CH group (P < 0.01). Reinstraint of CH-M group was less required than that of CH group (P < 0.05). Conclusions: Oral chloral hydrate (60 mg/kg) and hydroxyzine (1 mg/kg) combined with submucosal injection of midazolam was safer and showed more improved sedation effect than oral chloral hydrate (60 mg/kg) and hydroxyzine (1 mg/kg) without midazolam for sedation of pediatric dental patients.

• Korean Journal of Materials Research
• /
• v.12 no.11
• /
• pp.845-849
• /
• 2002

Alloys of $Fe_3$Al, $Fe_3$Al-6Cr, $Fe_3$Al-4Cr-1Mo, $Ni_3$Al, and $Ni_3$Al-2.8Cr were oxidized at $1000^{\circ}C$ in air, and the oxide scales formed were studied using XRD. SEM, EPMA, and TEM. The oxide scales that formed on $Fe_3$Al-based alloys consisted primarily of $\alpha$-$Al_2$$O_3$ containing a small amount of dissolved Fe and Cr ions, whereas those that formed on $Ni_3$Al-based alloys consisted primarily of $\alpha$-$Al_2$$O_3$, together with a small amount of $NiAl_2$$O_4$, NiO and dissolved Cr ions. For the entire alloys tested, nonadherent oxide scales formed, and voids were inevitably existed at the scale-matrix interface.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.365-368
• /
• 2002

We investigated the influence of RTP annealing of multi-layered metal films deposited on oxides layer. Two types of oxides, BPSG and P-7205, were used as a bottom layer under multi-layered metal film. The bonding was not good in metal/BPSG/Si samples because adhesion between metal layer and BPSG oxide layer was poor by interfacial reaction during RTP annealing above 650$^{\circ}C$. On the other hand bonding was always good in metal/ P-TEOS /Si samples regardless of annealing temperature. We observed the interface between oxide and metal layers using AES and TEM. The phosphorus and oxygen profile in interface between metal and oxide layers were different in metal/BPSG/Si and metal/P-TEOS/Si samples. We have known that the properties of interface was improved in metal/BPSG/Si samples when the sample was annealed below 650$^{\circ}C$.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.4
• /
• pp.719-724
• /
• 2003

In this paper, we have presented the simulation results about threshold voltage of nano scale lightly doped drain (LDD) MOSFET with halo doping profile. Device size is scaled down from 100nm to 40nm using generalized scaling. We have investigated the threshold voltage for constant field scaling and constant voltage scaling using the Van Dort Quantum Correction Model (QM) and direct tunneling current for each gate oxide thickness. We know that threshold voltage is decreasing in the constant field scaling and increasing in the constant voltage scaling when gate length is reducing, and direct tunneling current is increasing when gate oxide thickness is reducing. To minimize the roll off characteristics for threshold voltage of MOSFET with decreasing channel length, we know $\alpha$ value must be nearly 1 in the generalized scaling.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.922-925
• /
• 2003

The interest of self-organization materials that have uniform and regular structure in nano scale has been grown due to their utilization in various fields of nanotechnology. An attractive candidate among these materials is anodic aluminum oxide film, which are formed by anodization of aluminum in an appropriate acid solution. The anodic aluminum oxide film has a highly ordered porous structure with very uniform and nearly parallel pores that can be organized in an almost precise close-packed hexagonal structure. In this study, we attempt to make Au dot arrays, which were fabricated using anodic aluminum oxide film as an evaporation mask. The Au dot arrays have a uniform sized dots and spacing to its neighbors and the average diameter of Au dots is about 60 nm corresponding to them of the mask.

• Carbon letters
• /
• v.14 no.4
• /
• pp.247-250
• /
• 2013

In this study, we present a facile method of fabricating graphene oxide (GO) films on the surface of polyimide (PI) via layer-by-layer (LBL) assembly of charged GO. The positively charged amino-phenyl functionalized GO (APGO) is alternatively complexed with the negatively charged GO through an electrostatic LBL assembly process. Furthermore, we investigated the water vapor transmission rate and oxygen transmission rate of the prepared (reduced GO $[rGO]/rAPGO)_{10}$ deposited PI film (rGO/rAPGO/PI) and pure PI film. The water vapor transmission rate of the GO and APGO-coated PI composite film was increased due to the intrinsically hydrophilic property of the charged composite films. However, the oxygen transmission rate was decreased from 220 to 78 $cm^3/m^2{\cdot}day{\cdot}atm$, due to the barrier effect of the graphene films on the PI surface. Since the proposed method allows for large-scale production of graphene films, it is considered to have potential for utilization in various applications.