• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.637-639
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• 2010

최근 IPTV 시스템에서 다양한 서비스 제공을 위해 IPTV 컨텐츠 메타데이터의 효과적인 전송과 처리에 관심이 모아지고 있다. 이를 위해 TV-Anytime forum 에서는 대용량 IPTV 메타데이터의 전송을 위해 필수적인 바이너리 인코딩 기법으로서 MPEG-7 에 포함된 인코딩 방식인 BiM 을 권장하고 있다. 이에 본 논문에서는 상용 기술로서 사용시 로열티가 부과되는 BiM 을 대신하여 XML 문서의 인코딩을 위한 W3C 의 개방형 표준인 EXI 를 기반으로 TV-Anytime 메타데이터 전송 시스템을 설계하고 BiM 기반의 시스템과 성능을 비교하였다.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.3
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• pp.71-76
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• 2012

A chip interconnection technology for smart fabrics was investigated by using flip-chip bonding of SnBi low-temperature solder. A fabric substrate with a Cu leadframe could be successfully fabricated with transferring a Cu leadframe from a carrier film to a fabric by hot-pressing at $130^{\circ}C$. A chip specimen with SnBi solder bumps was formed by screen printing of SnBi solder paste and was connected to the Cu leadframe of the fabric substrate by flip-chip bonding at $180^{\circ}C$ for 60 sec. The average contact resistance of the SnBi flip-chip joint of the smart fabric was measured as $9m{\Omega}$.

• Journal of the Korean Chemical Society
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• v.40 no.7
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• pp.492-500
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• 1996

The solvent extraction of trace Bi, Cd and In in seawater samples using ammonium pyrrolidine dithiocarbamate(APDC) as a complexing agent was studied. The pH of sample solution, the amount of APDC, the type of solvent and the shaking time were investigated together with back-extraction conditions. After the pH of 200 mL seawater was adjusted to 4.0 and 5.0 mL of 1% APDC was added, analytes were extracted with 10.0 mL of MIBK by shaking for 35 minutes. The organic phase seperated was washed with a 0.05 M NaOH 10.0 mL to remove HPDC. The analytes were stripped by the back-extraction of 5 minute shaking with 5 mL of 4 M HNO3 containing 150 ㎍/mL Pd(Ⅱ). Detection limits of Bi, Cd and In were 0.038, 0.0057 and 0.023 ng/mL, respectively. Both of Bi(Ⅲ) and In(Ⅲ) were not detected in two kinds of water samples of the East Sea and the contents of Cd(Ⅱ) were 0.018 and 0.016 ng/mL. The recoveries of over 90% showed that this procedure was applicable to the determination of such trace elements in seawater samples.

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.79-79
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• 2010

Semimetallic bismuth (Bi) has been extensively investigated over the last decade since it exhibits very intriguing transport properties due to their highly anisotropic Fermi surface, low carrier concentration, long carrier mean free path l, and small effective carrier mass $m^*$. In particular, the great interest in Bi nanowires lies in the development of nanowire fabrication methods and the opportunity for exploring novel low-dimensional phenomena as well as practical application such as thermoelectricity[1]. In this work, we introduce a self-assembled interconnection of nanostructures produced by an on-film formation of nanowires (OFF-ON) method in order to form a highly ohmic Bi nanobridge. A Bi thin film was first deposited on a thermally oxidized Si (100) substrate at a rate of $40\;{\AA}/s$ by radio frequency (RF) sputtering at 300 K. The sputter system was kept in an ultra high vacuum (UHV) of $10^{-6}$ Torr before deposition, and sputtering was performed under an Ar gas pressure of 2m Torr for 180s. For the lateral growth of Bi nanowires, we sputtered a thin Cr (or $SiO_2$) layer on top of the Bi film. The Bi thin films were subsequently put into a custom-made vacuum furnace for thermal annealing to grow Bi nanowires by the OFF-ON method. After thermal annealing, the Bi nanowires cannot be pushed out from the topside of the Bi films due to the Cr (or $SiO_2$) layer. Instead, Bi nanowires grow laterally as a mean s of releasing the compressive stress. We fabricated a self-assembled Bi nanobridge (d=192 nm) device in-situ using OFF-ON through annealing at $250^{\circ}C$ for 10hours. From I-V measurements taken on the Bi nanobridge device, contacts to the nanobridge were found highly ohmic. The quality of the Bi nanobridge was also proved by the high MR of 123% obtained from transverse MR measurements. These results manifest the possibility of self-assembled nanowire interconnection between various nanostructures for a variety of applications and provide a simple device fabrication method to investigate transport properties on nanowires without complex patterning and etching processes.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.152-161
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• 2006

In order to test the capacity of Si(5 5 12) as a potential template for nanowire fabrication, Bi/Si(5 5 12) system has been studied by STM. With Bi deposition, Si(5 5 12) has been transformed to Si(3 3 7) terrace. Initially Bi atoms selectively replace Si-dimers and Si-adatoms with Bi-dimers and Bi-adatoms, respectively. With extended Bi adsorption, Bi-dimers adsorb on the pre-adsorbed Bi-dimers and Bi-atoms. These dimers in the second layer form Bi-dimer pairs having relatively stable $p^3$ bonding, Finally, the Bi-dimer adsorbs on the Bi-dimers in the second layer and saturates. It can be deduced that both surface transformation to (3 3 7) and site-selective Bi adsorption are possible due to substrate-strain relaxation through inserting Bi atoms into subsurface of Si substrate.

• Progress in Superconductivity and Cryogenics
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• v.6 no.1
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• pp.1-5
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• 2004

Long length of Bi-2223/Ag superconducting wives were fabricated by stacking and drawing process with advanced heat-treatment schedules. Intermediate annealing was carried out to increase the homogeneity and uniformity of the superconducting filaments embedded in the silver matrix. Phase modification from tetragonal to orthorhombic Bi-2212 by pre heat treatment(PHT) was executed to improve the texture and phase transformation of Bi-2223. Drawing stress was measured to predict the sausaging and stress limit. Rolling Parameters such as thickness. width and winding tension were investigated to roll the tape with uniformity. 1 km length of Bi-2223/Ag superconducting wires were fabricated without any breakage. Critical current (Je) of 270 m length of superconducting tapes was measured over than $70 A/cm^2$ continuously after final sintering.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.77-79
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• 1999

Bi$_2$Sr$_2$CaCu$_2$O(Bi-2212) thick films were fabricated on Y211 substrate by screen printing method. The aim of the study was to fabricate superconducting thick films on Y211 substrate by MPMG process. For this study, patterned samples by screen printing method were heated with MPMG process. The thickness of Bi2212 on substrate was about 20 ${\mu}{\textrm}{m}$ and these samples showed many Bi- 2212 phases.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.203-209
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• 2004

Compliant bi-stable mechanism allows two stable states within its operation range staying at one of the local minimum states of the potential energy. Energy storage characteristics of the bi-stable mechanism offer two distinct and repeatable stable states, which require no power input to maintain it at each stable state. This paper suggests an equivalent model of the chevron-type bi-stable microactuator using the equivalent spring stiffness in the rectilinear and the rotational directions. From this model the range of spring stiffness where the bi-stable mechanism can be operated is analyzed and compared with the results of the FEA (Finite Element Analysis) using ANSYS for the buckling analysis, both of which show a good agreement. Based on the analysis, a newly designed chevron-type bi-stable MEMS actuator using hinges is suggested for the latch-up operation. It is found that the experimental response characteristics of around 36V for the bi-stable actuation for the 60$mu extrm{m}$ stroke correspond very well to the results of the equivalent model analysis after the change in cross-sectional area by the fabrication process is taken into account. Together with the resonance frequency experiment where 1760Hz is measured, it is shown that the chevron-type bi-stable MEMS actuator using hinges is applicable to the optical switch as an actuator.

• Journal of Welding and Joining
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• v.20 no.2
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• pp.77-81
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• 2002

Many kinds of Pb-free solder have been investigated because of the environmental concerns. Sn-Ag-Cu system is well blown as most competitive Pb-free solder. However, since Sn-Ag-Cu system has relatively high melting point compared to Sn-Pb eutectic, it may a limitation, the some application. In this study, Bi and In contained solder of $Sn_3Ag_8Bi_5In$ which has relatively lower melting point, $188~204^{\circ}C$, was investigated. $Sn_3Ag_8Bi_5In$ solder ball of $500\mu\textrm{m}$ diameter was set on the Ni/Cu/Cr-UBM and reflow soldered in the range of $220~240^{\circ}C$ for 5~15s. The maximum shear strength of the solder ball was around 170mN by reflowing at $240^{\circ}C$ for 10s. Intermetallic compound formed on the UBM of Si-wafer was analysed by SEM(scanning electron microscope) and XRD(X-ray diffractometer).

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.43-47
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• 2001

Sn-3Ag-8Bi-5In was developed for the intermediate melting point solder. Although In-contained solder is expensive, its melting point is lower than these of Sn-Ag-Cu alloys. Sn-3Ag-8Bi-5In solder used for this research has a melting range of 188~$204^{\circ}C$. On this study wetting characteristics of Sn-3Ag-8Bi-5In were evaluated in order to investigate its availability as a Pb-free solder. Wettabilities of Sn-37Pb and Sn-3.5Ag solders were also studied to compare these of the Sn-3Ag-8Bi-5In. Experimental results showed that the zero-cross-time and wetting time at $240^{\circ}C$ for the Sn-3Ag-8Bi-5In were 1.1 and 2.2 second respectively. These values are a little better than these of Sn-37Pb and Sn-3.5Ag solders. The equilibrium wetting farce of the Sn-3Ag-8Bi-5In was 5.8 mN at $240^{\circ}C$, and it was tuned out to be a little higher than that of Sn-3.5Ag and lower than that of Sn-37Pb.