• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.12
• /
• pp.2263-2273
• /
• 2000

Catalytic wet air oxidation of acetic acid over Mn-Ce based catalysts deposited on various supports ($SiO_2$, $TiO_2$, $ZrO_2$), $ZrSiO_4$, $ZrO_2(10wt%)/TiO_2$) have been carried out in high pressure microreactors. Also, promotional effects by small addition(O.5~1.0 wt%) of p-type semiconductors (CoO, $Ag_2O$, SnO) have been investigated. From the screening tests for initial activity ranking, both Mn(2.8)-Ce(7.2 wt%) and Ru(O.4)Mn(2.7)-Ce(6.9 wt%) supported on $TiO_2$ were selected as the promising reference candidates. In $Mn-Ce/TiO_2$ reference catalyst, addition of small amount of each p-type semiconductor (Co, Sn and Ag) resulted in activity promotional effect and the degree of the increase was in the following order: Co> Ag > Sn. Especially, $Mn-Ce/TiO_2$ promoted with 0.5 wt% Co gave the 2.6 folds activity increase compared to the reference case attributing to the surface area increase as well as synergy effect. In $Ru-Mn-Ce/TiO_2$ reference catalyst, only Co(1.0 wt%) promoted case showed a little reaction rate increase.

• Journal of the Microelectronics and Packaging Society
• /
• v.18 no.3
• /
• pp.67-74
• /
• 2011

Keys to high wiring density semiconductor packages include flip-chip bonding and build-up substrate technologies. The current issues are the establishment of a fine pitch flip-chip bonding technology and a low coefficient of thermal expansion (CTE) substrate technology. In particular, electromigration and thermomigration in fine pitch flipchip joints have been recognized as a major reliability issue. In this paper, electromigration and thermomigration in Cu/Sn-3Ag-0.5Cu (SAC305)/Cu flip-chip joints and electromigration in Cu/In/Cu flip chip joints are investigated. In the electromigration test, a large electromigration void nucleation at the cathode, large growth of intermetallic compounds (IMCs) at the anode, a unique solder bump deformation towards the cathode, and the significantly prolonged electromigration lifetime with the underfill were observed in both types of joints. In addition, the effects of crystallographic orientation of Sn on electromigration were observed in the Cu/SAC305/Cu joints. In the thermomigration test, Cu dissolution was accelerated on the hot side, and formation of IMCs was enhanced on the cold side at a thermal gradient of about $60^{\circ}C$/cm, which was lower than previously reported. The rate of Cu atom migration was found comparable to that of electromigration under current conditions.

• Transactions of Materials Processing
• /
• v.7 no.5
• /
• pp.465-473
• /
• 1998

The effect of alloying elements of Ag-Cu-Zr-X brazing alloy on the microstructure and the bond strength of $Al_2O_3/Ni-Cr$ brazed steel joint was investigated. The reaction layer, $ZrO_2$ (a=5.146 ${\AA}$ , b=5.213 ${\AA}$ , c=5.311 ${\AA}$ )was formed at the interface of $Al_2O_3/Ni-Cr$ steel joint by the redox reaction between alumina and Zr. The addition of An and Al to the Ag-Cu-Zr brazing alloy gave rise to changes in the thickness of the reaction product layer and the morphology of the brazement. Sn caused the segregation of Zr was decreased b Al the $ZrO_2$ layer formed at the Ag-Cu-Zr-Al alloy was thinner than that of $ZrO_2$ formed at the Ag-Cu-Zr-An alloy. The fracture shear strength was strongly dependent on the microstructure of the brazement. Brazing with Ag-Cu-Zr-Sn alloy resulted in a better bond strength than with Ag-Cu-Zr or Ag-Cu-Zr-Al alloy.

• IE interfaces
• /
• v.22 no.1
• /
• pp.95-103
• /
• 2009

During the past few years, design of experiments (DOE) has been gaining acceptance in the telecommunications research community as a mean for designing and analyzing experiments economically and efficiently. In addition, the need for introducing a systematic robust design methodology (i.e., one of the most popular DOE methodologies) to network simulations has been increasing. In this paper, we present an architecture of voice over IP (VoIP) application and the E-Model for calculating the perceived quality of service (QoS). Then, we apply the Taguchi robust design methodology to optimize the perceived QoS of VoIP application, and describe the detailed step-by-step procedures. We have used ns-2 simulator to collect experimental data in which the SN ratio, a robustness measure, is analyzed to determine an optimal design condition. The analysis shows that "initial delay time in playout buffer" is a major control factor for ensuring robust behaviors of the perceived QoS of VoIP. Finally, we verify the proposed optimal design condition using a confirmation experiment.

• Journal of Korean Society for Quality Management
• /
• v.45 no.2
• /
• pp.293-306
• /
• 2017

Purpose: In this study, an optimal design level of influencing factors on semiconductor polishing process was determined to minimize flexion of both sides on wafers. Methods: First, significant interactions are determined by the stepwise regression method. ANOVA analysis on SN ratio and mean of dependent variable are performed to draw mean adjustment factors. In addition, the optimal levels of mean adjustment factors are decided by comparing means of each level of mean adjustment factors. Results: As a result of ANOVA, a mean adjustment factor was determined as a width of formed flexion on the plate. The mean of the difference has the nearest to 0 in the case when the width of formed flexion has level 2 (4mm). Conclusion: Optimal design levels of semiconductor polishing process are determined as follows; (i) load applied to the wafer carrier has a level 1 (3psi), (ii) load applied to the wafer has a level 1(3psi), (iii) the amount of slurry supplied during polishing has a level 3 (300 co/min), (iv) the width of formed flexion on the plate has level 2 (4mm).

• The Journal of Korean Academy of Prosthodontics
• /
• v.21 no.1
• /
• pp.9-26
• /
• 1983

In order to investigate the biocompatibility of silver-palladium alloys, gingival fibroblast was obtained from a healthy human gingival and cultured in MEM medium with the addition of silverpalladium alloys. Four different mixture of silver-palladium alloys comprising of Ag-Pd-Au, Ag-Pd-In and Ag-Sn were tested. Results were assessed by calculating the cell multiplication rate per millimeter of medium and morphological changes in cells were also observed and noted.The obtained results were as follows; 1. Ag-Pd-Au alloy was indicated to be most biocompatible with gingival fibroblast. Also there was a decrease in cytotoxicity of the alloy as the concentration of gold increased. 2. Ag-Pd alloy showed a decrease in cell multiplication rate as compared to Ag-Pd~Au alloy. 3. Silver-palladium alloy supplemented with Indium increased the cell multiplication rate. 4. Among the alloys tested, Ag-Sn alloy was indicated to be the most cytotoxic and the least biocompatible with human gingival fibroblast.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.6
• /
• pp.133-138
• /
• 2019

Recently, SNS is one of the most prominent areas and AR is a technology in the spotlight. In this paper, AR technology is applied to SNS to provide community functions and we develop the related technologies. The system developed in this paper provides differentiated communication among users by providing community functions applying location information and AR such as displaying AR message and finding a path using AR in current location. In addition, this paper presents a method of using the existing map APIs considering their characteristics as a method to obtain map information essential for the implementation of location-based AR.

• Journal of Sensor Science and Technology
• /
• v.1 no.2
• /
• pp.165-172
• /
• 1992

To determine the effect of additions of trivalent and pentavalent ions on the electrical conductivity and sensing behaviour, indium and antimony were incorporated in tin oxide by the coprecipitation method. Antimony may be considered to enter the cassiterite structure as pentavalent ions, thermal energy could excite electrons from these ions into the conduction band. Similarly the indium ions would enter the lattice as $In^{3+}$ but could accept electrons from the valence band, thereby becoming monovalent or divalent. These phenomena, however, how the potential barrier existing $SnO_{2}$ by addition of two kinds of ions could influence on the sensing behaviour in comparison with their influence on the resistivity were observed.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.2
• /
• pp.419-428
• /
• 2020

SNS media is gaining its media share with the benefits of digital technology, such as the convenience of physical access and the entertainment and interactivity of contents, and are becoming a part of users' lives. As media contents consumers move from traditional media to SNS, marketing communication activities are rapidly adapting to leading SNS platforms such as Facebook. This study compares how users perceive four advertisement attributes in each SNS, focusing on Facebook, Instagram, Kakao Story, and Twitter, where the media content creation and consumption systems are relatively similar to each other. The impact on eWOM intention was identified. In addition, we discussed effective SNS operation.

• Transactions on Electrical and Electronic Materials
• /
• v.10 no.3
• /
• pp.71-74
• /
• 2009

Electroplated Cu is a cost efficient metallization method in microelectronic packaging applications. Typically in 3-D chip staking technology, utilizing through silicon via (TSV), electroplated Cu metallization is inevitable for the throughput as well as reducing the cost of ownership (COO).To achieve a comparable film quality to sputtering or CVD, a pre-cleaning process as well as plating process is crucial. In this research, atmospheric plasma is employed to reduce the usage of chemicals, such as trichloroethylene (TCE) and sodium hydroxide (NaHO), by substituting the chemical assisted organic cleaning process with plasma surface treatment for Cu electroplating. By employing atmospheric plasma treatment, marginally acceptable electroplating and cleaning results are achieved without the use of hazardous chemicals. The experimental results show that the substitution of the chemical process with plasma treatment is plausible from an environmentally friendly aspect. In addition, plasma treatment on immersion Sn/Cu was also performed to find out the solderability of plasma treated Sn/Cu for practical industrial applications.