• 한국전기전자재료학회논문지
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• 제11권3호
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• pp.208-213
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• 1998

Microwave dielectric properties of $BiNbO_4$ containing CuO and $V_2O_5$(BN ceramics). BN ceramic with 0.07wt% $V_2O_5$ and 0.03wt% CuO (BNC3V7) was sintered at $900^{\circ}C$ where it is possible for these to be co-fired with Ag electrode. The dielectric constant of 44.3, TCF (Temperature Coefficient of resonance Frequency) of 2 ppm/$^{\circ}$ and Q${\times}f_o$ value (product of Quality value and resonance Frequency) of 22,000GHz could be obtained from those ceramics. It is observed that orthorhombic structure was stable $1000^{\circ}C$. As sintering temperature increases, the dielectric properties decreased. The main reasons were abnormal grain growth and the main peak of triclinic moved from the main peak of orthorhombic.

• Journal of Welding and Joining
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• 제21권6호
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• pp.20-25
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• 2003

Various welding methods such as Gas Tungsten Arc Welding(GTAW), magnetic force electrical resistance welding and Laser Beam Welding(LBW) are now available for end cap closure of nuclear fuel rods. Even though the resistance and GTA welding processes are widely used in manufacturing commercial fuel rods, they can not be recommended for the remote seal welding of fuel rods in the hot cell Facility due to the complexity of the electrode alignment, the difficulty in replacing parts in a remote manner and the large heat input for the thin sheath. Therefore, the Nd:YAG laser system using optical fiber transmission was selected for the end cap welding of irradiation fuel rods in the hot cell. The remote laser welding apparatus in the hot cell Facility was developed using a pulsed Nd:YAG laser of 500 watt average power with an optical fiber transmission. The weldment quality such as microstructure and mechanical strength was satisfactory. The optimum conditions of laser welding for encapsulating irradiation fuel rods in the hot cell were obtained.

• 한국분말재료학회지
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• 제6권2호
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• pp.152-162
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• 1999

The present study is concerned with the effect of PM process variables on the microstructure by using atomized superalloy powders. It is suggested that the inhomogeneity of composition is strongly dependent on the process variables. The contents of segregation elements of plasma rotating electrode process (PREP) powders are larger than those of Ar atomization (AA) powders. As HIP treatment temperature in-increases, the secondary phases on the prior particle boundaries (PPB) have continuous,uniform distribution and high density, but the amount of PPB decreases suddenly at 1150$^{\circ}$C. Segregated phases on the PPB are identified to be MC type carbide. Brittle MC type carbides on the PPB provide fracture initiation sites and preferred fracture path, thereby leading to intergranular type brittle fracture.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.232-233
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• 2015

The effects of various bath conditions such as surfactant concentration, bath pH, bath temperature, agitation of bath; as well as pulse parameters such as cathodic current density, pulse duty cycle and frequency, on the grain size, surface finish, and appearance of the tin plated coatings have been investigated. The plating bath under investigation is an aqueous acidic solution composed of a mixture of $SnSO_4$, $H_2SO_4$, and a surfactant. The bath conductivity and pH are measured by a glass pH electrode. The microstructure of the coatings produced is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and surface profilometry. XRD analysis shows that the deposits consist of tetragonal ${\beta}$-Sn crystal structure irrespective of plating conditions. The mechanism involved in the morphology evolution in response to various parameters and conditions has also been discussed.

• 동굴
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• 제76호
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• pp.1-13
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• 2006

Electrophoretic deposition (EPD) of alcohol YBCO suspensions on the Ag wire electrode is studied. Poly(ethylene glycol) was coordinated to a structure formed by the EPD process with YBCO particles. The suspension is characterized in terms of zeta potential and conductivity. The d.c electric fields of 200-300 V/cm are applied for 1-10 min. The optimal condition for the EPD allows modifying the properties and microstructure of the deposited films. Superconducting coatings with nanometer-sized pores and a preferred orientation along the c-axis were prepared from the result with chemically modified precursor solution. In contrast, YBCO coatings of submicrometer-sized pores and randomly orientated grains were prepared from the solution without PEG.

• 한국재료학회지
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• 제14권4호
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• pp.276-280
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• 2004

Carbon nanotubes(CNT) were synthesized by arc-discharge method. To fabricate CNT sensor, CNT powder was dispersed in $\alpha$-Terpinol($C_{10}$ $H_{17}$OH) solution. The CNT films were fabricated by screen printing on the interdigitated Pt/Pd alloy electrode. The microstructure of CNT film were observed by scanning electron microscopy (SEM). In order to investigate the gas sensing characteristics of the film, the CNT film was experimented to measure NH$_3$ response and recovery time. And this sensor shows better reproductibility and faster recovery time than another CNT sensors. We suggest the possibility to utilize a CNT as new sensing materials for environmental monitoring.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.295-299
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• 1999

The (S $r_{1-x}$C $a_{x}$)Ti $O_3$(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/ $SiO_2$/ Si) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained by substitution of Ca at 15[mol%]. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mo1%]. The dielectric constant changes almost linearly in temperature ranges of -80~ +90[$^{\circ}C$]. The temperature properties of the dielectric loss have a stable value within 0.02 independent of the substitutional contents of Ca. All SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency is observed above 200(kHz).)..

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권12호
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• pp.576-580
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• 2006

The $(Sr_{0.85}Ca_{0.15})TiO_3(SCT)$ thin films were deposited on Pt-coated electrode $(Pt/TiN/SiO_2/Si)$ using RF sputtering method according to the deposition condition. The crystallinity of SCT thin films were increased with increase of deposition temperature in the temperature range of $100{\sim}500[^{\circ}C]$. The optimum conditions of RF power and $Ar/O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin films was about $18.75[{\AA}/min]$ at the optimum condition. The composition of SCT thin films deposited on Si substrate is close to stoichiometry (1.102 in A/B ratio). The maximum dielectric constant of SCT thin film as obtained by annealing at $600^{\circ}C$.

• Journal of information and communication convergence engineering
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• 제1권1호
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• pp.27-30
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• 2003

Electrophoretic deposition (EPD) of alcohol YBCO suspensions on the Ag wire electrode is studied. Poly(ethylene glycol) was coordinated to a structure formed by the EPD process with YBCO particles. The suspension is characterized in terms of zeta potential and conductivity. The d.c electric fields of 200-300 V/cm are applied for 1-10 min. The optimal condition for the EPD allows modifying the properties and microstructure of the deposited films. Superconducting coatings with nanometer-sized pores and a preferred orientation along the c-axis were prepared from the result with chemically modified precursor solution. In contrast, YBCO coatings of submicrometer-sized pores and randomly orientated grains were prepared from the solution without PEG.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.189-193
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• 1997

(S $r_{0.85}$/C $a_{0.15}$)Ti $O_3$(SCT) thin films at various deposition temperature and rf power were grown by rf magnetron sputtering method on optimized Pt-based electrodes (Pt/TiN/ $SiO_2$/Si). The crystallinity of the films increases with increasing deposition temperature. SCT thin film is depend on the surface morphology and crystallinity of Pt films for bottom electrode. Dielectric constant of (S $r_{0.85}$C $a_{0.15}$)Ti $O_3$ thin films deposited on Si wafer substrate are larger with the increase of deposition temperature and gain size.in size.